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Novak JK, Gardner JG. Current models in bacterial hemicellulase-encoding gene regulation. Appl Microbiol Biotechnol 2024; 108:39. [PMID: 38175245 PMCID: PMC10766802 DOI: 10.1007/s00253-023-12977-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The discovery and characterization of bacterial carbohydrate-active enzymes is a fundamental component of biotechnology innovation, particularly for renewable fuels and chemicals; however, these studies have increasingly transitioned to exploring the complex regulation required for recalcitrant polysaccharide utilization. This pivot is largely due to the current need to engineer and optimize enzymes for maximal degradation in industrial or biomedical applications. Given the structural simplicity of a single cellulose polymer, and the relatively few enzyme classes required for complete bioconversion, the regulation of cellulases in bacteria has been thoroughly discussed in the literature. However, the diversity of hemicelluloses found in plant biomass and the multitude of carbohydrate-active enzymes required for their deconstruction has resulted in a less comprehensive understanding of bacterial hemicellulase-encoding gene regulation. Here we review the mechanisms of this process and common themes found in the transcriptomic response during plant biomass utilization. By comparing regulatory systems from both Gram-negative and Gram-positive bacteria, as well as drawing parallels to cellulase regulation, our goals are to highlight the shared and distinct features of bacterial hemicellulase-encoding gene regulation and provide a set of guiding questions to improve our understanding of bacterial lignocellulose utilization. KEY POINTS: • Canonical regulatory mechanisms for bacterial hemicellulase-encoding gene expression include hybrid two-component systems (HTCS), extracytoplasmic function (ECF)-σ/anti-σ systems, and carbon catabolite repression (CCR). • Current transcriptomic approaches are increasingly being used to identify hemicellulase-encoding gene regulatory patterns coupled with computational predictions for transcriptional regulators. • Future work should emphasize genetic approaches to improve systems biology tools available for model bacterial systems and emerging microbes with biotechnology potential. Specifically, optimization of Gram-positive systems will require integration of degradative and fermentative capabilities, while optimization of Gram-negative systems will require bolstering the potency of lignocellulolytic capabilities.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA.
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2
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Novak JK, Kennedy PG, Gardner JG. Transcriptomic analyses of bacterial growth on fungal necromass reveal different microbial community niches during degradation. Appl Environ Microbiol 2024:e0106224. [PMID: 39264205 DOI: 10.1128/aem.01062-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 08/28/2024] [Indexed: 09/13/2024] Open
Abstract
Bacteria are major drivers of organic matter decomposition and play crucial roles in global nutrient cycling. Although the degradation of dead fungal biomass (necromass) is increasingly recognized as an important contributor to soil carbon (C) and nitrogen (N) cycling, the genes and metabolic pathways involved in necromass degradation are less characterized. In particular, how bacteria degrade necromass containing different quantities of melanin, which largely control rates of necromass decomposition in situ, is largely unknown. To address this gap, we conducted a multi-timepoint transcriptomic analysis using three Gram-negative, bacterial species grown on low or high melanin necromass of Hyaloscypha bicolor. The bacterial species, Cellvibrio japonicus, Chitinophaga pinensis, and Serratia marcescens, belong to genera known to degrade necromass in situ. We found that while bacterial growth was consistently higher on low than high melanin necromass, the CAZyme-encoding gene expression response of the three species was similar between the two necromass types. Interestingly, this trend was not shared for genes encoding nitrogen utilization, which varied in C. pinensis and S. marcescens during growth on high vs low melanin necromass. Additionally, this study tested the metabolic capabilities of these bacterial species to grow on a diversity of C and N sources and found that the three bacteria have substantially different utilization patterns. Collectively, our data suggest that as necromass changes chemically over the course of degradation, certain bacterial species are favored based on their differential metabolic capacities.IMPORTANCEFungal necromass is a major component of the carbon (C) in soils as well as an important source of nitrogen (N) for plant and microbial growth. Bacteria associated with necromass represent a distinct subset of the soil microbiome and characterizing their functional capacities is the critical next step toward understanding how they influence necromass turnover. This is particularly important for necromass varying in melanin content, which has been observed to control the rate of necromass decomposition across a variety of ecosystems. Here we assessed the gene expression of three necromass-degrading bacteria grown on low or high melanin necromass and characterized their metabolic capacities to grow on different C and N substrates. These transcriptomic and metabolic studies provide the first steps toward assessing the physiological relevance of up-regulated CAZyme-encoding genes in necromass decomposition and provide foundational data for generating a predictive model of the molecular mechanisms underpinning necromass decomposition by soil bacteria.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland-Baltimore County, Baltimore, Maryland, USA
| | - Peter G Kennedy
- Department of Plant and Microbial Biology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland-Baltimore County, Baltimore, Maryland, USA
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3
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Li S, Yin Y, Zhang R, Wang C. The Impacts of Cellulose on Volatile Fatty Acid Production and the Microbial Community in Anaerobic Fermentation of Sludge at High and Medium Temperatures. Appl Biochem Biotechnol 2024:10.1007/s12010-024-05052-9. [PMID: 39212899 DOI: 10.1007/s12010-024-05052-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2024] [Indexed: 09/04/2024]
Abstract
During large-scale sewage treatment, a large amount of excessive sludge is produced, which will cause serious pollution in the environment. In recent years, anaerobic digestion technology has been widely promoted because it can achieve better sludge reduction, and the products and byproducts after anaerobic digestion can be fully utilized as resources. In this study, cellulose was added as the co-fermentation substrate during the fermentation process at 30 ℃ and 50 ℃ to enhance the production of VFAs. The result indicated that cellulose could significantly increase the yield of VFAs in both 30 ℃ and 50 ℃. Meanwhile, COD and reducing sugar generation in the fermentation process were also measure. Analysis of the microbial community structure at the class and genus levels revealed that the proportion of several genus closely related with cellulose degradation such as Cellvibrio, Fibrobacter, and Sporocytophaga were significantly increased with the addition of cellulose. Co-fermentation was recognized as an economic and environmental friendly strategy for sludge and other solid waste treatment. The analysis of the effect of cellulose as a substrate on the production of VFAs at high and medium temperatures is highly important for exploring ways to increase the production of VFAs in anaerobic fermentation.
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Affiliation(s)
- Suyu Li
- Miami College, Henan University, Henan Province, Kaifeng, 475000, China
| | - Yilong Yin
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Ruyan Zhang
- Miami College, Henan University, Henan Province, Kaifeng, 475000, China
| | - Chongyang Wang
- Miami College, Henan University, Henan Province, Kaifeng, 475000, China.
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4
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Liu J, Shi J, Gao J, Shi R, Zhu J, Jensen MS, Li C, Yang J, Zhao S, Sun A, Sun D, Zhang Y, Liu C, Liu W. Functional studies on tandem carbohydrate-binding modules of a multimodular enzyme possessing two catalytic domains. Appl Environ Microbiol 2024; 90:e0088824. [PMID: 38940565 PMCID: PMC11267928 DOI: 10.1128/aem.00888-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 06/09/2024] [Indexed: 06/29/2024] Open
Abstract
Although functional studies on carbohydrate-binding module (CBM) have been carried out extensively, the role of tandem CBMs in the enzyme containing multiple catalytic domains (CDs) is unclear. Here, we identified a multidomain enzyme (Lc25986) with a novel modular structure from lignocellulolytic bacterial consortium. It consists of a mannanase domain, two CBM65 domains (LcCBM65-1/LcCBM65-2), and an esterase domain. To investigate CBM function and domain interactions, full-length Lc25986 and its variants were constructed and used for enzymatic activity, binding, and bioinformatic analyses. The results showed that LcCBM65-1 and LcCBM65-2 both bind mannan and xyloglucan but not cellulose or β-1,3-1,4-glucan, which differs from the ligand specificity of reported CBM65s. Compared to LcCBM65-2, LcCBM65-1 showed a stronger ligand affinity and a preference for acetylation sites. Both CBM65s stimulated the enzymatic activities of their respective neighboring CDs against acetylated mannan, but did not contribute to the activities of the distal CDs. The time course of mannan hydrolysis indicated that the full-length Lc25986 was more effective in the complete degradation of mixed acetyl/non-acetyl substrates than the mixture of single-CD mutants. When acting on complex substrates, LcCBM65-1 not only improved the enzymatic activity of the mannanase domain, but also directed the esterase domain to the acetylated polysaccharides. LcCBM65-2 adopted a low affinity to reduce interference with the catalysis of the mannanase domain. These results demonstrate the importance of CBMs for the synergism between the two CDs of a multidomain enzyme and suggest that they contribute to the adequate degradation of complex substrates such as plant cell walls. IMPORTANCE Lignocellulolytic enzymes, particularly those of bacterial origin, often harbor multiple carbohydrate-binding modules (CBMs). However, the function of CBM multivalency remains poorly understood. This is especially true for enzymes that contain more than one catalytic domain (CD), as the interactions between CDs, CBMs, and CDs and CBMs can be complex. Our research demonstrates that homogeneous CBMs can have distinct functions in a multimodular enzyme. The tandem CBMs coordinate the CDs in catalytic conflict through their differences in binding affinity, ligand preference, and arrangement within the full-length enzyme. Additionally, although the synergism between mannanase and esterase is widely acknowledged, our study highlights the benefits of integrating the two enzymes into a single entity for the degradation of complex substrates. In summary, these findings enhance our understanding of the intra-synergism of a multimodular enzyme and emphasize the significance of multiple CBMs in this context.
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Affiliation(s)
- Jiawen Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jiani Shi
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jiahui Gao
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Rui Shi
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jingrong Zhu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Marcus Sepo Jensen
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Chenchen Li
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jing Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Siyi Zhao
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Aofei Sun
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Di Sun
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Ying Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Cong Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Weijie Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
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Gardner JG. Microbe Profile: Cellvibrio japonicus: living the sweet life via biomass break-down. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001450. [PMID: 38568197 PMCID: PMC11084541 DOI: 10.1099/mic.0.001450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/09/2024] [Indexed: 04/05/2024]
Abstract
Cellvibrio japonicus is a saprophytic bacterium proficient at environmental polysaccharide degradation for carbon and energy acquisition. Genetic, enzymatic, and structural characterization of C. japonicus carbohydrate active enzymes, specifically those that degrade plant and animal-derived polysaccharides, demonstrated that this bacterium is a carbohydrate-bioconversion specialist. Structural analyses of these enzymes identified highly specialized carbohydrate binding modules that facilitate activity. Steady progress has been made in developing genetic tools for C. japonicus to better understand the function and regulation of the polysaccharide-degrading enzymes it possesses, as well as to develop it as a biotechnology platform to produce renewable fuels and chemicals.
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Affiliation(s)
- Jeffrey G. Gardner
- Department of Biological Sciences, University of Maryland – Baltimore County Baltimore, Maryland, USA
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Zhu Y, Ke M, Yu Z, Lei C, Liu M, Yang Y, Lu T, Zhou NY, Peijnenburg WJGM, Tang T, Qian H. Combined effects of azoxystrobin and oxytetracycline on rhizosphere microbiota of Arabidopsis thaliana. ENVIRONMENT INTERNATIONAL 2024; 186:108655. [PMID: 38626494 DOI: 10.1016/j.envint.2024.108655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/10/2024] [Accepted: 04/10/2024] [Indexed: 04/18/2024]
Abstract
The rhizosphere is one of the key determinants of plant health and productivity. Mixtures of pesticides are commonly used in intensified agriculture. However, the combined mechanisms underlying their impacts on soil microbiota remain unknown. The present study revealed that the rhizosphere microbiota was more sensitive to azoxystrobin and oxytetracycline, two commonly used pesticides, than was the microbiota present in bulk soil. Moreover, the rhizosphere microbiota enhanced network complexity and stability and increased carbohydrate metabolism and xenobiotic biodegradation as well as the expression of metabolic genes involved in defence against pesticide stress. Co-exposure to azoxystrobin and oxytetracycline had antagonistic effects on Arabidopsis thaliana growth and soil microbial variation by recruiting organic-degrading bacteria and regulating ABC transporters to reduce pesticide uptake. Our study explored the composition and function of soil microorganisms through amplicon sequencing and metagenomic approaches, providing comprehensive insights into the synergistic effect of plants and rhizosphere microbiota on pesticides and contributing to our understanding of the ecological risks associated with pesticide use.
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Affiliation(s)
- Yuke Zhu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Mingjing Ke
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Zhitao Yu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Chaotang Lei
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Meng Liu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Yaohui Yang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Ning-Yi Zhou
- State Key Laboratory of Microbial Metabolism, and School of Life Science & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - W J G M Peijnenburg
- Institute of Environmental Sciences (CML), Leiden University, Leiden 2300, RA, the Netherlands; National Institute of Public Health and the Environment (RIVM), Center for Safety of Substances and Products, P.O. Box 1, Bilthoven, the Netherlands
| | - Tao Tang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture and Rural Affairs, Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, PR China.
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China.
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7
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Saikh SR, Mushtaque MA, Pramanick A, Prasad JK, Roy D, Saha S, Das SK. Fog caused distinct diversity of airborne bacterial communities enriched with pathogens over central Indo-Gangetic plain in India. Heliyon 2024; 10:e26370. [PMID: 38420377 PMCID: PMC10901028 DOI: 10.1016/j.heliyon.2024.e26370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/30/2023] [Accepted: 02/12/2024] [Indexed: 03/02/2024] Open
Abstract
Fog causes enhancement of bacterial loading in the atmosphere. Current study represents the impact of occurrences of fog on the alteration of diversity of airborne bacteria and their network computed from metagenomic data of airborne samples collected at Arthauli (25.95°N, 85.10°E) situated at central Indo-Gangetic Plain (IGP) during 1-14 January 2021. A distinct bacterial diversity with a complex network is identified in foggy condition due to the enrichment of unique types of bacteria. Present investigation highlights a statistically significant enrichment of airborne pathogenic bacteria found in a unique ecosystem within air evolved due to the occurrences of fog over central IGP. In the foggy network, Cutibacterium, an opportunistic pathogen, is identified to be interacting maximum (21 edges) with other bacteria with statistically significant copresence relation, which are responsible for various infections for human beings. A 40-60% increase (p < 0.01) in the abundance of pathogenic bacteria for respiratory and skin diseases is noticed in fog period. Among the fog-enriched bacteria, Cutibacterium, Herbaspirillum, Paenibacillus, and Tsukamurella are examples of opportunistic bacteria causing various respiratory diseases, while Paenibacillus can even cause skin cancer and acute lymphoblastic leukemia.
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Affiliation(s)
- Shahina Raushan Saikh
- Department of Physical Sciences, Bose Institute, Kolkata, India
- Department of Life Science & Bio-technology, Jadavpur University, Kolkata, India
| | | | | | | | - Dibakar Roy
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | - Sudipto Saha
- Department of Biological Sciences, Bose Institute, Kolkata, India
| | - Sanat Kumar Das
- Department of Physical Sciences, Bose Institute, Kolkata, India
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Mascelli GM, Garcia CA, Gardner JG. Genetic and enzymatic characterization of Amy13E from Cellvibrio japonicus reclassifies it as a cyclodextrinase also capable of α-diglucoside degradation. Appl Environ Microbiol 2024; 90:e0152123. [PMID: 38084944 PMCID: PMC10807414 DOI: 10.1128/aem.01521-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/31/2023] [Indexed: 01/25/2024] Open
Abstract
Cyclodextrinases are carbohydrate-active enzymes involved in the linearization of circular amylose oligosaccharides. Primarily thought to function as part of starch metabolism, there have been previous reports of bacterial cyclodextrinases also having additional enzymatic activities on linear malto-oligosaccharides. This substrate class also includes environmentally rare α-diglucosides such as kojibiose (α-1,2), nigerose (α-1,3), and isomaltose (α-1,6), all of which have valuable properties as prebiotics or low-glycemic index sweeteners. Previous genome sequencing of three Cellvibrio japonicus strains adapted to utilize these α-diglucosides identified multiple, but uncharacterized, mutations in each strain. One of the mutations identified was in the amy13E gene, which was annotated to encode a neopullulanase. In this report, we functionally characterized this gene and determined that it in fact encodes a cyclodextrinase with additional activities on α-diglucosides. Deletion analysis of amy13E found that this gene was essential for kojibiose and isomaltose metabolism in C. japonicus. Interestingly, a Δamy13E mutant was not deficient for cyclodextrin or pullulan utilization in C. japonicus; however, heterologous expression of the gene in E. coli was sufficient for cyclodextrin-dependent growth. Biochemical analyses found that CjAmy13E cleaved multiple substrates but preferred cyclodextrins and maltose, but had no activity on pullulan. Our characterization of the CjAmy13E cyclodextrinase is useful for refining functional enzyme predictions in related bacteria and for engineering enzymes for biotechnology or biomedical applications.IMPORTANCEUnderstanding the bacterial metabolism of cyclodextrins and rare α-diglucosides is increasingly important, as these sugars are becoming prevalent in the foods, supplements, and medicines humans consume that subsequently feed the human gut microbiome. Our analysis of a cyclomaltodextrinase with an expanded substrate range is significant because it broadens the potential applications of the GH13 family of carbohydrate active enzymes (CAZymes) in biotechnology and biomedicine. Specifically, this study provides a workflow for the discovery and characterization of novel activities in bacteria that possess a high number of CAZymes that otherwise would be missed due to complications with functional redundancy. Furthermore, this study provides a model from which predictions can be made why certain bacteria in crowded niches are able to robustly utilize rare carbon sources, possibly to gain a competitive growth advantage.
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Affiliation(s)
- Giulia M. Mascelli
- Department of Biological Sciences, University of Maryland, Baltimore, USA
| | - Cecelia A. Garcia
- Department of Biological Sciences, University of Maryland, Baltimore, USA
| | - Jeffrey G. Gardner
- Department of Biological Sciences, University of Maryland, Baltimore, USA
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9
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McGregor NS, de Boer C, Foucart QPO, Beenakker T, Offen WA, Codée JDC, Willems LI, Overkleeft HS, Davies GJ. A Multiplexing Activity-Based Protein-Profiling Platform for Dissection of a Native Bacterial Xyloglucan-Degrading System. ACS CENTRAL SCIENCE 2023; 9:2306-2314. [PMID: 38161374 PMCID: PMC10755729 DOI: 10.1021/acscentsci.3c00831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/26/2023] [Accepted: 11/06/2023] [Indexed: 01/03/2024]
Abstract
Bacteria and yeasts grow on biomass polysaccharides by expressing and excreting a complex array of glycoside hydrolase (GH) enzymes. Identification and annotation of such GH pools, which are valuable commodities for sustainable energy and chemistries, by conventional means (genomics, proteomics) are complicated, as primary sequence or secondary structure alignment with known active enzymes is not always predictive for new ones. Here we report a "low-tech", easy-to-use, and sensitive multiplexing activity-based protein-profiling platform to characterize the xyloglucan-degrading GH system excreted by the soil saprophyte, Cellvibrio japonicus, when grown on xyloglucan. A suite of activity-based probes bearing orthogonal fluorophores allows for the visualization of accessory exo-acting glycosidases, which are then identified using biotin-bearing probes. Substrate specificity of xyloglucanases is directly revealed by imbuing xyloglucan structural elements into bespoke activity-based probes. Our ABPP platform provides a highly useful tool to dissect xyloglucan-degrading systems from various sources and to rapidly select potentially useful ones. The observed specificity of the probes moreover bodes well for the study of other biomass polysaccharide-degrading systems, by modeling probe structures to those of desired substrates.
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Affiliation(s)
| | - Casper de Boer
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands
| | - Quentin P. O. Foucart
- Department
of Chemistry, The University of York, Heslington, York YO10 5DD, United
Kingdom
| | - Thomas Beenakker
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands
| | - Wendy A. Offen
- Department
of Chemistry, The University of York, Heslington, York YO10 5DD, United
Kingdom
| | - Jeroen D. C. Codée
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands
| | - Lianne I. Willems
- York
Structural Biology Laboratory and York Biomedical Research Institute,
Department of Chemistry, University of York, Heslington, York YO10 5DD, United
Kingdom
| | - Herman S. Overkleeft
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands
| | - Gideon J. Davies
- Department
of Chemistry, The University of York, Heslington, York YO10 5DD, United
Kingdom
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10
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Garcia CA, Gardner JG. RNAseq analysis of Cellvibrio japonicus during starch utilization differentiates between genes encoding carbohydrate active enzymes controlled by substrate detection or growth rate. Microbiol Spectr 2023; 11:e0245723. [PMID: 37800973 PMCID: PMC10714805 DOI: 10.1128/spectrum.02457-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/22/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE Understanding the bacterial metabolism of starch is important as this polysaccharide is a ubiquitous ingredient in foods, supplements, and medicines, all of which influence gut microbiome composition and health. Our RNAseq and growth data set provides a valuable resource to those who want to better understand the regulation of starch utilization in Gram-negative bacteria. These data are also useful as they provide an example of how to approach studying a starch-utilizing bacterium that has many putative amylases by coupling transcriptomic data with growth assays to overcome the potential challenges of functional redundancy. The RNAseq data can also be used as a part of larger meta-analyses to compare how C. japonicus regulates carbohydrate active enzymes, or how this bacterium compares to gut microbiome constituents in terms of starch utilization potential.
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Affiliation(s)
- Cecelia A. Garcia
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
| | - Jeffrey G. Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
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11
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Joyce GE, Kagan IA, Flythe MD, Davis BE, Schendel RR. Profiling of cool-season forage arabinoxylans via a validated HPAEC-PAD method. FRONTIERS IN PLANT SCIENCE 2023; 14:1116995. [PMID: 36993841 PMCID: PMC10040848 DOI: 10.3389/fpls.2023.1116995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 02/27/2023] [Indexed: 06/19/2023]
Abstract
Cool-season pasture grasses contain arabinoxylans (AX) as their major cell wall hemicellulosic polysaccharide. AX structural differences may influence enzymatic degradability, but this relationship has not been fully explored in the AX from the vegetative tissues of cool-season forages, primarily because only limited AX structural characterization has been performed in pasture grasses. Structural profiling of forage AX is a necessary foundation for future work assessing enzymatic degradability and may also be useful for assessing forage quality and suitability for ruminant feed. The main objective of this study was to optimize and validate a high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) method for the simultaneous quantification of 10 endoxylanase-released xylooligosaccharides (XOS) and arabinoxylan oligosaccharides (AXOS) in cool-season forage cell wall material. The following analytical parameters were determined or optimized: chromatographic separation and retention time (RT), internal standard suitability, working concentration range (CR), limit of detection (LOD), limit of quantification (LOQ), relative response factor (RRF), and quadratic calibration curves. The developed method was used to profile the AX structure of four cool-season grasses commonly grown in pastures (timothy, Phleum pratense L.; perennial ryegrass, Lolium perenne L.; tall fescue, Schedonorus arundinaceus (Schreb.) Dumort.; and Kentucky bluegrass, Poa pratensis L.). In addition, the cell wall monosaccharide and ester-linked hydroxycinnamic acid contents were determined for each grass. The developed method revealed unique structural aspects of the AX structure of these forage grass samples that complemented the results of the cell wall monosaccharide analysis. For example, xylotriose, representing an unsubstituted portion of the AX polysaccharide backbone, was the most abundantly-released oligosaccharide in all the species. Perennial rye samples tended to have greater amounts of released oligosaccharides compared to the other species. This method is ideally suited to monitor structural changes of AX in forages as a result of plant breeding, pasture management, and fermentation of plant material.
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Affiliation(s)
- Glenna E. Joyce
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY, United States
| | - Isabelle A. Kagan
- Forage-Animal Production Research Unit, U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Lexington, KY, United States
| | - Michael D. Flythe
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY, United States
- Forage-Animal Production Research Unit, U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Lexington, KY, United States
| | - Brittany E. Davis
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY, United States
- Forage-Animal Production Research Unit, U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Lexington, KY, United States
| | - Rachel R. Schendel
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY, United States
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12
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Tsudome M, Tachioka M, Miyazaki M, Tsuda M, Takaki Y, Deguchi S. Marinagarivorans cellulosilyticus sp. nov., a cellulolytic bacterium isolated from the deep-sea off Noma-misaki, Japan. Int J Syst Evol Microbiol 2023; 73. [PMID: 36862579 DOI: 10.1099/ijsem.0.005748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
Cells from strain GE09T, isolated from an artificially immersed nanofibrous cellulose plate in the deep sea, were Gram-stain-negative, motile, aerobic cells that could grow with cellulose as their only nutrient. Strain GE09T was placed among members of Cellvibrionaceae, in the Gammaproteobacteria, with Marinagarivorans algicola Z1T, a marine degrader of agar, as the closest relative (97.4 % similarity). The average nucleotide identity and digital DNA-DNA hybridization values between GE09T and M. algicola Z1T were 72.5 and 21.2 %, respectively. Strain GE09T degraded cellulose, xylan and pectin, but not starch, chitin and agar. The different carbohydrate-active enzymes encoded in the genomes of strain GE09T and M. algicola Z1T highlights their differences in terms of target energy sources and reflects their isolation environments. The major cellular fatty acids of strain GE09T were C18 : 1 ω7c, C16 : 0 and C16 : 1 ω7c. The polar lipid profile showed phosphatidylglycerol and phosphatidylethanolamine. The major respiratory quinone was Q-8. Based on these distinct taxonomic characteristics, strain GE09T represents a new species in the genus Marinagarivorans, for which we propose the name Marinagarivorans cellulosilyticus sp. nov. (type strain GE09T=DSM 113420T=JCM 35003T).
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Affiliation(s)
- Mikiko Tsudome
- Research Center for Bioscience and Nanoscience, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
| | - Mikako Tachioka
- Research Center for Bioscience and Nanoscience, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
| | - Masayuki Miyazaki
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, JAMSTEC, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
| | - Miwako Tsuda
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, JAMSTEC, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
| | - Yoshihiro Takaki
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, JAMSTEC, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
| | - Shigeru Deguchi
- Research Center for Bioscience and Nanoscience, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
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13
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Novak JK, Gardner JG. Galactomannan utilization by Cellvibrio japonicus relies on a single essential α-galactosidase encoded by the aga27A gene. Mol Microbiol 2023; 119:312-325. [PMID: 36604822 DOI: 10.1111/mmi.15024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/22/2022] [Accepted: 12/30/2022] [Indexed: 01/07/2023]
Abstract
Plant mannans are a component of lignocellulose that can have diverse compositions in terms of its backbone and side-chain substitutions. Consequently, the degradation of mannan substrates requires a cadre of enzymes for complete reduction to substituent monosaccharides that can include mannose, galactose, and/or glucose. One bacterium that possesses this suite of enzymes is the Gram-negative saprophyte Cellvibrio japonicus, which has 10 predicted mannanases from the Glycoside Hydrolase (GH) families 5, 26, and 27. Here we describe a systems biology approach to identify and characterize the essential mannan-degrading components in this bacterium. The transcriptomic analysis uncovered significant changes in gene expression for most mannanases, as well as many genes that encode carbohydrate active enzymes (CAZymes) when mannan was actively being degraded. A comprehensive mutational analysis characterized 54 CAZyme-encoding genes in the context of mannan utilization. Growth analysis of the mutant strains found that the man26C, aga27A, and man5D genes, which encode a mannobiohydrolase, α-galactosidase, and mannosidase, respectively, were important for the deconstruction of galactomannan, with Aga27A being essential. Our updated model of mannan degradation in C. japonicus proposes that the removal of galactose sidechains from substituted mannans constitutes a crucial step for the complete degradation of this hemicellulose.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, Maryland, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, Maryland, USA
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14
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Astafyeva Y, Gurschke M, Streit WR, Krohn I. Interplay between the microalgae Micrasterias radians and its symbiont Dyadobacter sp. HH091. Front Microbiol 2022; 13:1006609. [PMID: 36312980 PMCID: PMC9606717 DOI: 10.3389/fmicb.2022.1006609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Based on previous research, related to detailed insight into mutualistic collaboration of microalga and its microbiome, we established an artificial plant-bacteria system of the microalga Micrasterias radians MZCH 672 and the bacterial isolate Dyadobacter sp. HH091. The bacteria, affiliated with the phylum Bacteroidota, strongly stimulated growth of the microalga when it was added to axenic algal cultures. For further advances, we studied the isolate HH091 and its interaction with the microalga M. radians using transcriptome and extensive genome analyses. The genome of HH091 contains predicted polysaccharide utilizing gene clusters co-working with the type IX secretion system (T9SS) and conceivably involved in the algae-bacteria liaison. Here, we focus on characterizing the mechanism of T9SS, implementing the attachment and invasion of microalga by Dyadobacter sp. HH091. Omics analysis exposed T9SS genes: gldK, gldL, gldM, gldN, sprA, sprE, sprF, sprT, porU and porV. Besides, gld genes not considered as the T9SS components but required for gliding motility and protein secretion (gldA, gldB, gldD, gldF, gldG, gldH, gldI, gldJ), were also identified at this analysis. A first model of T9SS apparatus of Dyadobacter was proposed in a course of this research. Using the combination of fluorescence labeling of Dyadobacter sp. HH091, we examined the bacterial colonisation and penetration into the cell wall of the algal host M. radians MZCH 672.
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15
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Zhang Y, Zhang J, Yan C, Fang M, Wang L, Huang Y, Wang F. Metabolome and Microbiome Signatures in the Leaves of Wild Tea Plant Resources Resistant to Pestalotiopsis theae. Front Microbiol 2022; 13:907962. [PMID: 35910661 PMCID: PMC9335280 DOI: 10.3389/fmicb.2022.907962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/23/2022] [Indexed: 11/28/2022] Open
Abstract
Tea (Camellia sinensis) is an important crop that is mainly used in the food industry. This study using the metabolome and microbiome investigates the resistance factors of wild tea plant resources against tea gray blight disease, which is caused by Pestalotiopsis theae (Sawada) Steyaert. According to the interaction analysis of tea leaves and pathogenic fungus, the resistance of wild tea plant resource “R1” (Resistance 1) to tea gray blight disease was significantly higher than that of wild tea plant resource “S1” (Susceptibility 1). The difference between “R1” and “S1” in the metabolome was obvious. There were 145 metabolites that significantly changed. The phenolic acids and flavonoids were the major increased categories in “R1,” and it included 4-O-glucosyl-sinapate and petunidin-3-o-(6”-o-p-coumaroyl) rutinoside. Six metabolic pathways were significantly enriched, including aminoacyl-tRNA biosynthesis, flavone, and flavonol biosynthesis. In terms of bacteria, there was no significant difference between “S1” and “R1” in the principal component analysis (PCA). Pseudomonas was the major bacterial genus in “S1” and “R1.” In addition, each of the two resources had its own predominant genus: Cellvibirio was a predominant bacterial genus in “S1” and Candidatus_competibacter was a predominant bacterial genus in “R1.” In terms of fungi, the fungal diversity and the abundance of the two tea plant resource samples could be distinguished clearly. The fungal component of “S1” was more abundant than that of “R1” at the genus level. Toxicocladosporium was the predominant fungal genus of “S1,” and Filobasidium was the predominant fungal genus of “R1.” The relative abundance of unclassified-norank-norank-Chloroplast and Penicillium were significantly different between “S1” and “R1.” Penicillium was identified as a potential biomarker. They correlated with some metabolites enriched in “S1” or “R1,” such as L-arginine and quercetin-3-o-(2”-o-rhamnosyl) rutinoside-7-o-glucoside. Overall, phenolic acids, flavonoids, and Penicillium could be functional metabolites or microorganisms that contributed to improving the resistance of wild tea plant resources to tea gray blight disease.
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Affiliation(s)
- Yuqian Zhang
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Jie Zhang
- Henan Key Laboratory of Tea Plant Comprehensive Utilization in South Henan, College of Tea Science, Xinyang Agriculture and Forestry University, Xinyang, China
| | - Changyu Yan
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Meishan Fang
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Lijie Wang
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yahui Huang
- College of Horticulture, South China Agricultural University, Guangzhou, China
- Yahui Huang
| | - Feiyan Wang
- College of Horticulture, South China Agricultural University, Guangzhou, China
- *Correspondence: Feiyan Wang
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16
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Li X, Kouzounis D, Kabel MA, de Vries RP. GH10 and GH11 endoxylanases in Penicillium subrubescens: comparative characterization and synergy with GH51, GH54, GH62 α-L-arabinofuranosidases from the same fungus. N Biotechnol 2022; 70:84-92. [PMID: 35597447 DOI: 10.1016/j.nbt.2022.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 11/25/2022]
Abstract
Penicillium subrubescens has an expanded set of genes encoding putative endoxylanases (PsXLNs) compared to most other Penicillia and other fungi. In this study, all GH10 and GH11 PsXLNs were produced heterologously in Pichia pastoris and characterized. They were active towards beech wood xylan (BWX) and wheat flour arabinoxylan (WAX), and showed stability over a wide pH range. Additionally, PsXLNs released distinct oligosaccharides from WAX, and showed significant cooperative action with P. subrubescens α-L-arabinofuranosidases (PsABFs) from GH51 or GH54 for WAX degradation, giving insight into a more diverse XLN and ABF system for the efficient degradation of complex hemicelluloses. Homology modelling analysis pointed out differences in the catalytic center of PsXLNs, which are discussed in view of the different modes of action observed. These findings facilitate understanding of structural requirements for substrate recognition to contribute to recombinant XLN engineering for biotechnological applications.
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Affiliation(s)
- Xinxin Li
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Dimitrios Kouzounis
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Mirjam A Kabel
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
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17
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Spatiotemporal Heterogeneity and Intragenus Variability in Rhizobacterial Associations with
Brassica rapa
Growth. mSystems 2022; 7:e0006022. [PMID: 35575562 PMCID: PMC9239066 DOI: 10.1128/msystems.00060-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial communities in the rhizosphere are distinct from those in soils and are influenced by stochastic and deterministic processes during plant development. These communities contain bacteria capable of promoting growth in host plants through various strategies. While some interactions are characterized in mechanistic detail using model systems, others can be inferred from culture-independent methods, such as 16S amplicon sequencing, using machine learning methods that account for this compositional data type. To characterize assembly processes and identify community members associated with plant growth amid the spatiotemporal variability of the rhizosphere, we grew Brassica rapa in a greenhouse time series with amended and reduced microbial treatments. Inoculation with a native soil community increased plant leaf area throughout the time series by up to 28%. Despite identifying spatially and temporally variable amplicon sequence variants (ASVs) in both treatments, inoculated communities were more highly connected and assembled more deterministically overall. Using a generalized linear modeling approach controlling for spatial variability, we identified 43 unique ASVs that were positively or negatively associated with leaf area, biomass, or growth rates across treatments and time stages. ASVs of the genus Flavobacterium dominated rhizosphere communities and showed some of the strongest positive and negative correlations with plant growth. Members of this genus, and growth-associated ASVs more broadly, exhibited variable connectivity in networks independent of growth association (positive or negative). These findings suggest host-rhizobacterial interactions vary temporally at narrow taxonomic scales and present a framework for identifying rhizobacteria that may work independently or in concert to improve agricultural yields. IMPORTANCE The rhizosphere, the zone of soil surrounding plant roots, is a hot spot for microbial activity, hosting bacteria capable of promoting plant growth in ways like increasing nutrient availability or fighting plant pathogens. This microbial system is highly diverse and most bacteria are unculturable, so to identify specific bacteria associated with plant growth, we used culture-independent community DNA sequencing combined with machine learning techniques. We identified 43 specific bacterial sequences associated with the growth of the plant Brassica rapa in different soil microbial treatments and at different stages of plant development. Most associations between bacterial abundances and plant growth were positive, although similar bacterial groups sometimes had different effects on growth. Why this happens will require more research, but overall, this study provides a way to identify native bacteria from plant roots that might be isolated and applied to boost agricultural yields.
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18
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Kojima K, Sunagawa N, Yoshimi Y, Tryfona T, Samejima M, Dupree P, Igarashi K. Acetylated xylan degradation by glycoside hydrolase family 10 and 11 xylanases from the white-rot fungus <i>Phanerochaete chrysosporium</i>. J Appl Glycosci (1999) 2022; 69:35-43. [PMID: 35891899 PMCID: PMC9276525 DOI: 10.5458/jag.jag.jag-2021_0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/28/2022] [Indexed: 11/22/2022] Open
Abstract
Endo-type xylanases are key enzymes in microbial xylanolytic systems, and xylanases belonging to glycoside hydrolase (GH) families 10 or 11 are the major enzymes degrading xylan in nature. These enzymes have typically been characterized using xylan prepared by alkaline extraction, which removes acetyl sidechains from the substrate, and thus the effect of acetyl groups on xylan degradation remains unclear. Here, we compare the ability of GH10 and 11 xylanases, PcXyn10A and PcXyn11B, from the white-rot basidiomycete Phanerochaete chrysosporium to degrade acetylated and deacetylated xylan from various plants. Product quantification revealed that PcXyn10A effectively degraded both acetylated xylan extracted from Arabidopsis thaliana and the deacetylated xylan obtained by alkaline treatment, generating xylooligosaccharides. In contrast, PcXyn11B showed limited activity towards acetyl xylan, but showed significantly increased activity after deacetylation of the xylan. Polysaccharide analysis using carbohydrate gel electrophoresis showed that PcXyn11B generated a broad range of products from native acetylated xylans extracted from birch wood and rice straw, including large residual xylooligosaccharides, while non-acetylated xylan from Japanese cedar was readily degraded into xylooligosaccharides. These results suggest that the degradability of native xylan by GH11 xylanases is highly dependent on the extent of acetyl group substitution. Analysis of 31 fungal genomes in the Carbohydrate-Active enZymes database indicated that the presence of GH11 xylanases is correlated to that of carbohydrate esterase (CE) family 1 acetyl xylan esterases (AXEs), while this is not the case for GH10 xylanases. These findings may imply co-evolution of GH11 xylanases and CE1 AXEs.
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Affiliation(s)
- Keisuke Kojima
- Department of Biomaterial Sciences, The University of Tokyo
| | - Naoki Sunagawa
- Department of Biomaterial Sciences, The University of Tokyo
| | | | | | | | - Paul Dupree
- Department of Biochemistry, University of Cambridge
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Sagarika MS, Parameswaran C, Senapati A, Barala J, Mitra D, Prabhukarthikeyan SR, Kumar A, Nayak AK, Panneerselvam P. Lytic polysaccharide monooxygenases (LPMOs) producing microbes: A novel approach for rapid recycling of agricultural wastes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150451. [PMID: 34607097 DOI: 10.1016/j.scitotenv.2021.150451] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/12/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Out of the huge quantity of agricultural wastes produced globally, rice straw is one of the most abundant ligno-cellulosic waste. For efficient utilization of these wastes, several cost-effective biological processes are available. The practice of field level in-situ or ex-situ decomposition of rice straw is having less degree of adoption due to its poor decomposition ability within a short time span between rice harvest and sowing of the next crop. Agricultural wastes including rice straw are in general utilized by using lignocellulose degrading microbes for industrial metabolite or compost production. However, bioconversion of crystalline cellulose and lignin present in the waste, into simple molecules is a challenging task. To resolve this issue, researchers have identified a novel new generation microbial enzyme i.e., lytic polysaccharide monooxygenases (LPMOs) and reported that the combination of LPMOs with other glycolytic enzymes are found efficient. This review explains the progress made in LPMOs and their role in lignocellulose bioconversion and the possibility of exploring LPMOs producers for rapid decomposition of agricultural wastes. Also, it provides insights to identify the knowledge gaps in improving the potential of the existing ligno-cellulolytic microbial consortium for efficient utilization of agricultural wastes at industrial and field levels.
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Affiliation(s)
- Mahapatra Smruthi Sagarika
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India; Indira Gandhi Agricultural University, Raipur, Chhattisgarh 492012, India
| | | | - Ansuman Senapati
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
| | - Jatiprasad Barala
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
| | - Debasis Mitra
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
| | | | - Anjani Kumar
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
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Characterization of an extracellular α-xylosidase involved in xyloglucan degradation in Aspergillus oryzae. Appl Microbiol Biotechnol 2021; 106:675-687. [PMID: 34971412 DOI: 10.1007/s00253-021-11744-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/08/2021] [Accepted: 12/12/2021] [Indexed: 10/19/2022]
Abstract
α-Xylosidases release the α-D-xylopyranosyl side chain from di- and oligosaccharides derived from xyloglucans and are involved in xyloglucan degradation. In this study, an extracellular α-xylosidase, named AxyB, is identified and characterized in Aspergillus oryzae. AxyB belongs to the glycoside hydrolase family 31 and releases D-xylose from isoprimeverose (α-D-xylopyranosyl-(1 → 6)-D-glucopyranose) and xyloglucan oligosaccharides. In the hydrolysis of xyloglucan oligosaccharides (XLLG, Glc4Xyl3Gal2 nonasaccharide; XLXG/XXLG, Glc4Xyl3Gal1 octasaccharide; and XXXG, Glc4Xyl3 heptasaccharide), AxyB releases one molecule of the xylopyranosyl side chain attached to the non-reducing end of the β-1,4-glucan main chain of these xyloglucan oligosaccharides to yield GLLG (Glc4Xyl2Gal2), GLXG/GXLG (Glc4Xyl2Gal1), and GXXG (Glc4Xyl2). A. oryzae has both extracellular and intracellular α-xylosidase, suggesting that xyloglucan oligosaccharides are degraded by a combination of isoprimeverose-producing oligoxyloglucan hydrolase and intracellular α-xylosidase and a combination of extracellular α-xylosidase and β-glucosidase(s) in A. oryzae. KEY POINTS: • An extracellular α-xylosidase, AxyB, is identified in Aspergillus oryzae. • AxyB releases the xylopyranosyl side chain from xyloglucan oligosaccharides. • Different sets of glycosidases degrade xyloglucan oligosaccharides in A. oryzae.
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21
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Identification and characterization of a novel endo-β-1,4-glucanase from a soil metagenomic library. Carbohydr Res 2021; 510:108460. [PMID: 34700218 DOI: 10.1016/j.carres.2021.108460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 10/08/2021] [Accepted: 10/17/2021] [Indexed: 11/23/2022]
Abstract
A cosmid clone cZFYN1413 with CMCase activity was identified from a soil metagenomic library. The sequence analysis of a subclone of cZFYN1413 revealed an endo-β-1,4-glucanase gene ZFYN1413 belonging to glycoside hydrolase family 6 and a transmembrane region in the N-terminal of ZFYN1413. Expression of ZFYN1413 in Escherichia coli BL21 (DE3) resulted in ZFYN1413-87, which was a truncated protein cleaved in transmembrane region of ZFYN1413. ZFYN1413-87 was expressed and its enzyme properties were studied. ZFYN1413-87 possessed strong endo-β-1,4-glucanase activity, and 52% of the activity could be retained after the protein was treated in buffer of pH 3.0 for 2 h. The study provided a special example of endo-β-1,4-glucanase in GH6 family.
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22
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Ruen-Pham K, Graham LE, Satjarak A. Spatial Variation of Cladophora Epiphytes in the Nan River, Thailand. PLANTS (BASEL, SWITZERLAND) 2021; 10:2266. [PMID: 34834629 PMCID: PMC8622721 DOI: 10.3390/plants10112266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
Cladophora is an algal genus known to be ecologically important. It provides habitats for microorganisms known to provide ecological services such as biosynthesis of cobalamin (vitamin B12) and nutrient cycling. Most knowledge of microbiomes was obtained from studies of lacustrine Cladophora species. However, whether lotic freshwater Cladophora microbiomes are as complex as the lentic ones or provide similar ecological services is not known. To illuminate these issues, we used amplicons of 16S rDNA, 18S rDNA, and ITS to investigate the taxonomy and diversity of the microorganisms associated with replicate Cladophora samples from three sites along the Nan River, Thailand. Results showed that the diversity of prokaryotic and eukaryotic members of Cladophora microbiomes collected from different sampling sites was statistically different. Fifty percent of the identifiable taxa were shared across sampling sites: these included organisms belonging to different trophic levels, decomposers, and heterotrophic bacteria. These heterogeneous assemblages of bacteria, by functional inference, have the potential to perform various ecological functions, i.e., cellulose degradation, cobalamin biosynthesis, fermentative hydrogen production, ammonium oxidation, amino acid fermentation, dissimilatory reduction of nitrate to ammonium, nitrite reduction, nitrate reduction, sulfur reduction, polyphosphate accumulation, denitrifying phosphorus-accumulation, and degradation of aromatic compounds. Results suggested that river populations of Cladophora provide ecologically important habitat for microorganisms that are key to nutrient cycling in lotic ecosystems.
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Affiliation(s)
- Karnjana Ruen-Pham
- Plants of Thailand Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand;
| | - Linda E. Graham
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA;
| | - Anchittha Satjarak
- Plants of Thailand Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand;
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23
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Gardner JG, Schreier HJ. Unifying themes and distinct features of carbon and nitrogen assimilation by polysaccharide-degrading bacteria: a summary of four model systems. Appl Microbiol Biotechnol 2021; 105:8109-8127. [PMID: 34611726 DOI: 10.1007/s00253-021-11614-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/24/2022]
Abstract
Our current understanding of enzymatic polysaccharide degradation has come from a huge number of in vitro studies with purified enzymes. While this vast body of work has been invaluable in identifying and characterizing novel mechanisms of action and engineering desirable traits into these enzymes, a comprehensive picture of how these enzymes work as part of a native in vivo system is less clear. Recently, several model bacteria have emerged with genetic systems that allow for a more nuanced study of carbohydrate active enzymes (CAZymes) and how their activity affects bacterial carbon metabolism. With these bacterial model systems, it is now possible to not only study a single nutrient system in isolation (i.e., carbohydrate degradation and carbon metabolism), but also how multiple systems are integrated. Given that most environmental polysaccharides are carbon rich but nitrogen poor (e.g., lignocellulose), the interplay between carbon and nitrogen metabolism in polysaccharide-degrading bacteria can now be studied in a physiologically relevant manner. Therefore, in this review, we have summarized what has been experimentally determined for CAZyme regulation, production, and export in relation to nitrogen metabolism for two Gram-positive (Caldicellulosiruptor bescii and Clostridium thermocellum) and two Gram-negative (Bacteroides thetaiotaomicron and Cellvibrio japonicus) polysaccharide-degrading bacteria. By comparing and contrasting these four bacteria, we have highlighted the shared and unique features of each, with a focus on in vivo studies, in regard to carbon and nitrogen assimilation. We conclude with what we believe are two important questions that can act as guideposts for future work to better understand the integration of carbon and nitrogen metabolism in polysaccharide-degrading bacteria. KEY POINTS: • Regardless of CAZyme deployment system, the generation of a local pool of oligosaccharides is a common strategy among Gram-negative and Gram-positive polysaccharide degraders as a means to maximally recoup the energy expenditure of CAZyme production and export. • Due to the nitrogen deficiency of insoluble polysaccharide-containing substrates, Gram-negative and Gram-positive polysaccharide degraders have a diverse set of strategies for supplementation and assimilation. • Future work needs to precisely characterize the energetic expenditures of CAZyme deployment and bolster our understanding of how carbon and nitrogen metabolism are integrated in both Gram-negative and Gram-positive polysaccharide-degrading bacteria, as both of these will significantly influence a given bacterium's suitability for biotechnology applications.
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Affiliation(s)
- Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.
| | - Harold J Schreier
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.,Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
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24
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Clocchiatti A, Hannula SE, Rizaludin MS, Hundscheid MPJ, klein Gunnewiek PJA, Schilder MT, Postma J, de Boer W. Impact of Cellulose-Rich Organic Soil Amendments on Growth Dynamics and Pathogenicity of Rhizoctonia solani. Microorganisms 2021; 9:microorganisms9061285. [PMID: 34204724 PMCID: PMC8231496 DOI: 10.3390/microorganisms9061285] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/25/2021] [Accepted: 06/03/2021] [Indexed: 01/04/2023] Open
Abstract
Cellulose-rich amendments stimulate saprotrophic fungi in arable soils. This may increase competitive and antagonistic interactions with root-infecting pathogenic fungi, resulting in lower disease incidence. However, cellulose-rich amendments may also stimulate pathogenic fungi with saprotrophic abilities, thereby increasing plant disease severity. The current study explores these scenarios, with a focus on the pathogenic fungus Rhizoctonia solani. Saprotrophic growth of R. solani on cellulose-rich materials was tested in vitro. This confirmed paper pulp as a highly suitable substrate for R. solani, whereas its performance on wood sawdusts varied with tree species. In two pot experiments, the effects of amendment of R. solani-infected soil with cellulose-rich materials on performance of beetroot seedlings were tested. All deciduous sawdusts and paper pulp stimulated soil fungal biomass, but only oak, elder and beech sawdusts reduced damping-off of beetroot. Oak sawdust amendment gave a consistent stimulation of saprotrophic Sordariomycetes fungi and of seedling performance, independently of the time between amendment and sowing. In contrast, paper pulp caused a short-term increase in R. solani abundance, coinciding with increased disease severity for beet seedlings sown immediately after amendment. However, damping-off of beetroot was reduced if plants were sown two or four weeks after paper pulp amendment. Cellulolytic bacteria, including Cytophagaceae, responded to paper pulp during the first two weeks and may have counteracted further spread of R. solani. The results showed that fungus-stimulating, cellulose-rich amendments have potential to be used for suppression of R. solani. However, such amendments require a careful consideration of material choice and application strategy.
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Affiliation(s)
- Anna Clocchiatti
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; (M.S.R.); (M.P.J.H.); (P.J.A.k.G.)
- Correspondence: (A.C.); (W.d.B.)
| | - Silja Emilia Hannula
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands;
| | - Muhammad Syamsu Rizaludin
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; (M.S.R.); (M.P.J.H.); (P.J.A.k.G.)
| | - Maria P. J. Hundscheid
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; (M.S.R.); (M.P.J.H.); (P.J.A.k.G.)
| | - Paulien J. A. klein Gunnewiek
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; (M.S.R.); (M.P.J.H.); (P.J.A.k.G.)
| | - Mirjam T. Schilder
- Biointeractions and Plant Health, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; (M.T.S.); (J.P.)
| | - Joeke Postma
- Biointeractions and Plant Health, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; (M.T.S.); (J.P.)
| | - Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; (M.S.R.); (M.P.J.H.); (P.J.A.k.G.)
- Soil Biology Group, Wageningen University, 6708 PB Wageningen, The Netherlands
- Correspondence: (A.C.); (W.d.B.)
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25
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Tóth Á, Máté R, Kutasi J, Bata-Vidács I, Tóth E, Táncsics A, Kovács G, Nagy I, Kukolya J. Cellvibrio polysaccharolyticus sp. nov., a cellulolytic bacterium isolated from agricultural soil. Int J Syst Evol Microbiol 2021; 71. [PMID: 33999790 DOI: 10.1099/ijsem.0.004805] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel Gram-reaction-negative bacterial strain, designated Ka43T, was isolated from agricultural soil and characterised using a polyphasic approach to determine its taxonomic position. On the basis of 16S rRNA gene sequence analysis, the strain shows highest similarity (97.1 %) to Cellvibrio diazotrophicus E50T. Cells of strain Ka43T are aerobic, motile, short rods. The major fatty acids are summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH), C18 : 1 ω7c and C16 : 0. The only isoprenoid quinone is Q-8. The polar lipid profile includes phosphatidylethanolamine, phosphatidylglycerol, four phospholipids, two lipids and an aminolipid. The assembled genome of strain Ka43T has a total length of 4.2 Mb and the DNA G+C content is 51.6 mol%. Based on phenotypic data, including chemotaxonomic characteristics and analysis of the 16S rRNA gene sequences, it was concluded that strain Ka43T represents a novel species in the genus Cellvibrio, for which the name Cellvibrio polysaccharolyticus sp. nov. is proposed. The type strain of the species is strain Ka43T (=LMG 31577T=NCAIM B.02637T).
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Affiliation(s)
- Ákos Tóth
- Research Group for Food Biotechnology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Budapest, Hungary
| | - Rózsa Máté
- BioFil Microbiological, Biotechnological and Biochemical Ltd, Budapest, Hungary
| | - József Kutasi
- BioFil Microbiological, Biotechnological and Biochemical Ltd, Budapest, Hungary
| | - Ildikó Bata-Vidács
- Research Group for Food Biotechnology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Budapest, Hungary
| | - Erika Tóth
- Department of Microbiology, Eötvös Loránd University, Budapest, Hungary
| | - András Táncsics
- Department of Molecular Ecology, Institute of Aquaculture and Environmental Safety, Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
| | - Gábor Kovács
- University of Sopron, Sopron, Hungary.,SeqOmics Biotechnology Ltd, Szeged, Hungary
| | - István Nagy
- Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary.,SeqOmics Biotechnology Ltd, Szeged, Hungary
| | - József Kukolya
- Research Group for Food Biotechnology, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Budapest, Hungary
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26
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Monge EC, Gardner JG. Efficient chito-oligosaccharide utilization requires two TonB-dependent transporters and one hexosaminidase in Cellvibrio japonicus. Mol Microbiol 2021; 116:366-380. [PMID: 33735458 DOI: 10.1111/mmi.14717] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/13/2021] [Accepted: 03/14/2021] [Indexed: 11/29/2022]
Abstract
Chitin utilization by microbes plays a significant role in biosphere carbon and nitrogen cycling, and studying the microbial approaches used to degrade chitin will facilitate our understanding of bacterial strategies to degrade a broad range of recalcitrant polysaccharides. The early stages of chitin depolymerization by the bacterium Cellvibrio japonicus have been characterized and are dependent on one chitin-specific lytic polysaccharide monooxygenase and nonredundant glycoside hydrolases from the family GH18 to generate chito-oligosaccharides for entry into metabolism. Here, we describe the mechanisms for the latter stages of chitin utilization by C. japonicus with an emphasis on the fate of chito-oligosaccharides. Our systems biology approach combined transcriptomics and bacterial genetics using ecologically relevant substrates to determine the essential mechanisms for chito-oligosaccharide transport and catabolism in C. japonicus. Using RNAseq analysis we found a coordinated expression of genes that encode polysaccharide-degrading enzymes. Mutational analysis determined that the hex20B gene product, predicted to encode a hexosaminidase, was required for efficient utilization of chito-oligosaccharides. Furthermore, two gene loci (CJA_0353 and CJA_1157), which encode putative TonB-dependent transporters, were also essential for chito-oligosaccharides utilization. This study further develops our model of C. japonicus chitin metabolism and may be predictive for other environmentally or industrially important bacteria.
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Affiliation(s)
- Estela C Monge
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA
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27
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Manus MB, Kuthyar S, Perroni-Marañón AG, de la Mora AN, Amato KR. Comparing different sample collection and storage methods for field-based skin microbiome research. Am J Hum Biol 2021; 34:e23584. [PMID: 33644952 DOI: 10.1002/ajhb.23584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES The skin, as well as its microbial communities, serves as the primary interface between the human body and the surrounding environment. In order to implement the skin microbiome into human biology research, there is a need to explore the effects of different sample collection and storage methodologies, including the feasibility of conducting skin microbiome studies in field settings. METHODS We collected 99 skin microbiome samples from nine infants living in Veracruz, Mexico using a dual-tipped "dry" swab on the right armpit, palm, and forehead and a "wet" swab (0.15 M NaCl and 0.1% Tween 20) on the same body parts on the left side of the body. One swab from each collection method was stored in 95% ethanol while the other was frozen at -20°C. 16S rRNA amplicon sequencing generated data on bacterial diversity and community composition, which were analyzed using PERMANOVA, linear mixed effects models, and an algorithm-based classifier. RESULTS Treatment (wet_ethanol, wet_freezer, dry_ethanol, and dry_freezer) had an effect (~10% explanatory power) on the bacterial community diversity and composition of skin samples, although body site exhibited a stronger effect (~20% explanatory power). Within treatments, the collection method (wet vs. dry) affected measures of bacterial diversity to a greater degree than did the storage method (ethanol vs. freezer). CONCLUSIONS Our study provides novel information on skin microbiome sample collection and storage methods, suggesting that ethanol storage is suitable for research in resource-limited settings. Our results highlight the need for future study design to account for interbody site microbial variation.
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Affiliation(s)
- Melissa B Manus
- Department of Anthropology, Northwestern University, Evanston, Illinois, USA
| | - Sahana Kuthyar
- Department of Anthropology, Northwestern University, Evanston, Illinois, USA.,Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | | | | | - Katherine R Amato
- Department of Anthropology, Northwestern University, Evanston, Illinois, USA
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28
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New Family of Carbohydrate-Binding Modules Defined by a Galactosyl-Binding Protein Module from a Cellvibrio japonicus Endo-Xyloglucanase. Appl Environ Microbiol 2021; 87:e0263420. [PMID: 33355108 DOI: 10.1128/aem.02634-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Carbohydrate-binding modules (CBMs) are usually appended to carbohydrate-active enzymes (CAZymes) and serve to potentiate catalytic activity, for example, by increasing substrate affinity. The Gram-negative soil saprophyte Cellvibrio japonicus is a valuable source for CAZyme and CBM discovery and characterization due to its innate ability to degrade a wide array of plant polysaccharides. Bioinformatic analysis of the CJA_2959 gene product from C. japonicus revealed a modular architecture consisting of a fibronectin type III (Fn3) module, a cryptic module of unknown function (X181), and a glycoside hydrolase family 5 subfamily 4 (GH5_4) catalytic module. We previously demonstrated that the last of these, CjGH5F, is an efficient and specific endo-xyloglucanase (M. A. Attia, C. E. Nelson, W. A. Offen, N. Jain, et al., Biotechnol Biofuels 11:45, 2018, https://doi.org/10.1186/s13068-018-1039-6). In the present study, C-terminal fusion of superfolder green fluorescent protein in tandem with the Fn3-X181 modules enabled recombinant production and purification from Escherichia coli. Native affinity gel electrophoresis revealed binding specificity for the terminal galactose-containing plant polysaccharides galactoxyloglucan and galactomannan. Isothermal titration calorimetry further evidenced a preference for galactoxyloglucan polysaccharide over short oligosaccharides comprising the limit-digest products of CjGH5F. Thus, our results identify the X181 module as the defining member of a new CBM family, CBM88. In addition to directly revealing the function of this CBM in the context of xyloglucan metabolism by C. japonicus, this study will guide future bioinformatic and functional analyses across microbial (meta)genomes. IMPORTANCE This study reveals carbohydrate-binding module family 88 (CBM88) as a new family of galactose-binding protein modules, which are found in series with diverse microbial glycoside hydrolases, polysaccharide lyases, and carbohydrate esterases. The definition of CBM88 in the carbohydrate-active enzymes classification (http://www.cazy.org/CBM88.html) will significantly enable future microbial (meta)genome analysis and functional studies.
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29
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Morais MAB, Coines J, Domingues MN, Pirolla RAS, Tonoli CCC, Santos CR, Correa JBL, Gozzo FC, Rovira C, Murakami MT. Two distinct catalytic pathways for GH43 xylanolytic enzymes unveiled by X-ray and QM/MM simulations. Nat Commun 2021; 12:367. [PMID: 33446650 PMCID: PMC7809346 DOI: 10.1038/s41467-020-20620-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 12/10/2020] [Indexed: 02/07/2023] Open
Abstract
Xylanolytic enzymes from glycoside hydrolase family 43 (GH43) are involved in the breakdown of hemicellulose, the second most abundant carbohydrate in plants. Here, we kinetically and mechanistically describe the non-reducing-end xylose-releasing exo-oligoxylanase activity and report the crystal structure of a native GH43 Michaelis complex with its substrate prior to hydrolysis. Two distinct calcium-stabilized conformations of the active site xylosyl unit are found, suggesting two alternative catalytic routes. These results are confirmed by QM/MM simulations that unveil the complete hydrolysis mechanism and identify two possible reaction pathways, involving different transition state conformations for the cleavage of xylooligosaccharides. Such catalytic conformational promiscuity in glycosidases is related to the open architecture of the active site and thus might be extended to other exo-acting enzymes. These findings expand the current general model of catalytic mechanism of glycosidases, a main reaction in nature, and impact on our understanding about their interaction with substrates and inhibitors.
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Affiliation(s)
- Mariana A B Morais
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil
- Departament de Química Inorgànica i Orgànica & Institut de Química Teórica i Computacional (IQTCUB), Universitat de Barcelona, Barcelona, 08028, Spain
| | - Joan Coines
- Departament de Química Inorgànica i Orgànica & Institut de Química Teórica i Computacional (IQTCUB), Universitat de Barcelona, Barcelona, 08028, Spain
| | - Mariane N Domingues
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil
| | - Renan A S Pirolla
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil
| | - Celisa C C Tonoli
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil
| | - Camila R Santos
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil
| | - Jessica B L Correa
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil
| | - Fabio C Gozzo
- Dalton Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, Campinas, 13083-970, Brazil
| | - Carme Rovira
- Departament de Química Inorgànica i Orgànica & Institut de Química Teórica i Computacional (IQTCUB), Universitat de Barcelona, Barcelona, 08028, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, 08010, Spain.
| | - Mario T Murakami
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-100, Brazil.
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30
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Ai M, Zhu Y, Jia X. Recent advances in constructing artificial microbial consortia for the production of medium-chain-length polyhydroxyalkanoates. World J Microbiol Biotechnol 2021; 37:2. [PMID: 33392870 DOI: 10.1007/s11274-020-02986-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/20/2020] [Indexed: 11/29/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are a class of high-molecular-weight polyesters made from hydroxy fatty acid monomers. PHAs produced by microorganisms have diverse structures, variable physical properties, and good biodegradability. They exhibit similar physical properties to petroleum-based plastics but are much more environmentally friendly. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs), in particular, have attracted much interest because of their low crystallinity, low glass transition temperature, low tensile strength, high elongation at break, and customizable structure. Nevertheless, high production costs have hindered their practical application. The use of genetically modified organisms can reduce production costs by expanding the scope of substrate utilization, improving the conversion efficiency of substrate to product, and increasing the yield of mcl-PHAs. The yield of mcl-PHAs produced by a pure culture of an engineered microorganism was not high enough because of the limitations of the metabolic capacity of a single microorganism. The construction of artificial microbial consortia and the optimization of microbial co-cultivation have been studied. This type of approach avoids the addition of precursor substances and helps synthesize mcl-PHAs more efficiently. In this paper, we reviewed the design and construction principles and optimized control strategies for artificial microbial consortia that produce mcl-PHAs. We described the metabolic advantages of co-cultivating artificial microbial consortia using low-value substrates and discussed future perspectives on the production of mcl-PHAs using artificial microbial consortia.
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Affiliation(s)
- Mingmei Ai
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yinzhuang Zhu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Xiaoqiang Jia
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China.
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China.
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31
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Trehalose Degradation by Cellvibrio japonicus Exhibits No Functional Redundancy and Is Solely Dependent on the Tre37A Enzyme. Appl Environ Microbiol 2020; 86:AEM.01639-20. [PMID: 32917758 DOI: 10.1128/aem.01639-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/08/2020] [Indexed: 12/12/2022] Open
Abstract
The α-diglucoside trehalose has historically been known as a component of the bacterial stress response, though it more recently has been studied for its relevance in human gut health and biotechnology development. The utilization of trehalose as a nutrient source by bacteria relies on carbohydrate-active enzymes, specifically those of the glycoside hydrolase family 37 (GH37), to degrade the disaccharide into substituent glucose moieties for entry into metabolism. Environmental bacteria using oligosaccharides for nutrients often possess multiple carbohydrate-active enzymes predicted to have the same biochemical activity and therefore are thought to be functionally redundant. In this study, we characterized trehalose degradation by the biotechnologically important saprophytic bacterium Cellvibrio japonicus This bacterium possesses two predicted α-α-trehalase genes, tre37A and tre37B, and our investigation using mutational analysis found that only the former is essential for trehalose utilization by C. japonicus Heterologous expression experiments found that only the expression of the C. japonicus tre37A gene in an Escherichia coli treA mutant strain allowed for full utilization of trehalose. Biochemical characterization of C. japonicus GH37 activity determined that the tre37A gene product is solely responsible for cleaving trehalose and is an acidic α-α-trehalase. Bioinformatic and mutational analyses indicate that Tre37A directly cleaves trehalose to glucose in the periplasm, as C. japonicus does not possess a phosphotransferase system. This study facilitates the development of a comprehensive metabolic model for α-linked disaccharides in C. japonicus and more broadly expands our understanding of the strategies that saprophytic bacteria employ to capture diverse carbohydrates from the environment.IMPORTANCE The metabolism of trehalose is becoming increasingly important due to the inclusion of this α-diglucoside in a number of foods and its prevalence in the environment. Bacteria able to utilize trehalose in the human gut possess a competitive advantage, as do saprophytic microbes in terrestrial environments. While the biochemical mechanism of trehalose degradation is well understood, what is less clear is how bacteria acquire this metabolite from the environment. The significance of this report is that by using the model saprophyte Cellvibrio japonicus, we were able to functionally characterize the two predicted trehalase enzymes that the bacterium possesses and determined that the two enzymes are not equivalent and are not functionally redundant. The results and approaches used to understand the complex physiology of α-diglucoside metabolism from this study can be applied broadly to other polysaccharide-degrading bacteria.
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32
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Kaira GS, Kapoor M. Molecular advancements on over-expression, stability and catalytic aspects of endo-β-mannanases. Crit Rev Biotechnol 2020; 41:1-15. [PMID: 33032458 DOI: 10.1080/07388551.2020.1825320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The hydrolysis of mannans by endo-β-mannanases continues to gather significance as exemplified by its commercial applications in food, feed, and a rekindled interest in biorefineries. The present review provides a comprehensive account of fundamental research and fascinating insights in the field of endo-β-mannanase engineering in order to improve over-expression and to decipher molecular determinants governing activity-stability during harsh conditions, substrate recognition, polysaccharide specificity, endo/exo mode of action and multi-functional activities in the modular polypeptide. In-depth analysis of the available literature has also been made on rational and directed evolution approaches, which have translated native endo-β-mannanases into superior biocatalysts for satisfying industrial requirements.
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Affiliation(s)
- Gaurav Singh Kaira
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Mukesh Kapoor
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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33
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Li RK, Hu YJ, He YJ, Ng TB, Zhou ZM, Ye XY. A thermophilic chitinase 1602 from the marine bacterium Microbulbifer sp. BN3 and its high-level expression in Pichia pastoris. Biotechnol Appl Biochem 2020; 68:1076-1085. [PMID: 32924196 DOI: 10.1002/bab.2027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 09/07/2020] [Indexed: 11/12/2022]
Abstract
Chitinases play an important role in many industrial processes, including the preparation of oligosaccharides with potential applications. In the present study, a 1,713 bp gene of Chi1602, derived from a marine bacterium Microbulbifer sp. BN3, encoding a GH18 family chitinase, was expressed at high levels in Pichia pastoris. Distinct from most of the marine chitinases, the recombinant chitinase 1602 exhibited maximal activity at 60 °C and over a broad pH range between 5.0 and 9.0, and was stable at 50 °C and over the pH range 4.0-9.0. The hydrolytic products derived from colloidal chitins comprised mainly (GlcNAc)2 and GlcNAc, indicating that rChi1602 is a GH18 processive chitinase in conformity with its hypothetical structure. However, rChi1602 showed traces of β-N-acetylglucosaminidase activity on substrates such as powder chitin, chitosan, and ethylene glycol chitin. The thermophilic rChi1602, which manifests adaptation to a wide pH range and can be expressed at a high level in P. pastoris, is advantageous for applications in industrial processes.
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Affiliation(s)
- Ren Kuan Li
- The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fuzhou, Fujian, People's Republic of China.,National Engineering Laboratory for High-efficient Enzyme Expression, Fuzhou, Fujian, People's Republic of China
| | - Ya Juan Hu
- The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fuzhou, Fujian, People's Republic of China
| | - Yu Jie He
- The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fuzhou, Fujian, People's Republic of China
| | - Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People's Republic of China
| | - Zhi Min Zhou
- The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fuzhou, Fujian, People's Republic of China
| | - Xiu Yun Ye
- The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fuzhou, Fujian, People's Republic of China.,National Engineering Laboratory for High-efficient Enzyme Expression, Fuzhou, Fujian, People's Republic of China
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34
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Hwang J, Hari A, Cheng R, Gardner JG, Lobo D. Kinetic modeling of microbial growth, enzyme activity, and gene deletions: An integrated model of β-glucosidase function in Cellvibrio japonicus. Biotechnol Bioeng 2020; 117:3876-3890. [PMID: 32833226 DOI: 10.1002/bit.27544] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 07/11/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022]
Abstract
Understanding the complex growth and metabolic dynamics in microorganisms requires advanced kinetic models containing both metabolic reactions and enzymatic regulation to predict phenotypic behaviors under different conditions and perturbations. Most current kinetic models lack gene expression dynamics and are separately calibrated to distinct media, which consequently makes them unable to account for genetic perturbations or multiple substrates. This challenge limits our ability to gain a comprehensive understanding of microbial processes towards advanced metabolic optimizations that are desired for many biotechnology applications. Here, we present an integrated computational and experimental approach for the development and optimization of mechanistic kinetic models for microbial growth and metabolic and enzymatic dynamics. Our approach integrates growth dynamics, gene expression, protein secretion, and gene-deletion phenotypes. We applied this methodology to build a dynamic model of the growth kinetics in batch culture of the bacterium Cellvibrio japonicus grown using either cellobiose or glucose media. The model parameters were inferred from an experimental data set using an evolutionary computation method. The resulting model was able to explain the growth dynamics of C. japonicus using either cellobiose or glucose media and was also able to accurately predict the metabolite concentrations in the wild-type strain as well as in β-glucosidase gene deletion mutant strains. We validated the model by correctly predicting the non-diauxic growth and metabolite consumptions of the wild-type strain in a mixed medium containing both cellobiose and glucose, made further predictions of mutant strains growth phenotypes when using cellobiose and glucose media, and demonstrated the utility of the model for designing industrially-useful strains. Importantly, the model is able to explain the role of the different β-glucosidases and their behavior under genetic perturbations. This integrated approach can be extended to other metabolic pathways to produce mechanistic models for the comprehensive understanding of enzymatic functions in multiple substrates.
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Affiliation(s)
- Jeanice Hwang
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
| | - Archana Hari
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
| | - Raymond Cheng
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
| | - Daniel Lobo
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland, USA
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Bacterial Community Structure Dynamics in Meloidogyne incognita-Infected Roots and Its Role in Worm-Microbiome Interactions. mSphere 2020; 5:5/4/e00306-20. [PMID: 32669465 PMCID: PMC7364209 DOI: 10.1128/msphere.00306-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Plant parasitic nematodes such as Meloidogyne incognita have a complex life cycle, occurring sequentially in various niches of the root and rhizosphere. They are known to form a range of interactions with bacteria and other microorganisms that can affect their densities and virulence. High-throughput sequencing can reveal these interactions in high temporal and geographic resolutions, although thus far we have only scratched the surface. In this study, we have carried out a longitudinal sampling scheme, repeatedly collecting rhizosphere soil, roots, galls, and second-stage juveniles from 20 plants to provide a high-resolution view of bacterial succession in these niches, using 16S rRNA metabarcoding. Our findings indicate that a structured community develops in the root, in which gall communities diverge from root segments lacking a gall, and that this structure is maintained throughout the crop season. We describe the successional process leading toward this structure, which is driven by interactions with the nematode and later by an increase in bacteria often found in hypoxic and anaerobic environments. We present evidence that this structure may play a role in the nematode's chemotaxis toward uninfected root segments. Finally, we describe the J2 epibiotic microenvironment as ecologically deterministic, in part, due to the active bacterial attraction of second-stage juveniles.IMPORTANCE The study of high-resolution successional processes within tightly linked microniches is rare. Using the power and relatively low cost of metabarcoding, we describe the bacterial succession and community structure in roots infected with root-knot nematodes and in the nematodes themselves. We reveal separate successional processes in galls and adjacent non-gall root sections, which are driven by the nematode's life cycle and the progression of the crop season. With their relatively low genetic diversity, large geographic range, spatially complex life cycle, and the simplified agricultural ecosystems they occupy, root-knot nematodes can serve as a model organism for terrestrial holobiont ecology. This perspective can improve our understanding of the temporal and spatial aspects of biological control efficacy.
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Cruz Barrera M, Jakobs-Schoenwandt D, Gómez MI, Serrato J, Ruppel S, Patel AV. Formulating bacterial endophyte: Pre-conditioning of cells and the encapsulation in amidated pectin beads. ACTA ACUST UNITED AC 2020; 26:e00463. [PMID: 32405468 PMCID: PMC7210509 DOI: 10.1016/j.btre.2020.e00463] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/14/2020] [Accepted: 04/23/2020] [Indexed: 11/15/2022]
Abstract
Endophytic activity of pre-conditioned and encapsulated cells in amidated pectin beads Hydroxyectoine-added cells within pectin amidated beads increase endophytismus Radish yields increased through the application of encapsulated K. radicincitans cells Entrapped cells chemoattraction towards radish visualized by multispectral imaging
Despite the benefits of bacterial endophytes, recent studies on the mostly Gram-negative bacteria lack of regard for formulation strategies. The encapsulation into biopolymeric materials such as amidated pectins hydrogels is a suitable alternative. Here, this research aimed at supporting the capability of the plant growth-promoting bacteria Kosakonia radicincitans DSM16656T to endophytically colonize plant seedlings. In this approach, the pre-conditioned cells through osmoadaptation and hydroxyectoine accumulation were used. In general, pre-osmoadapted and hydroxyectoine-supplemented bacteria cells formulated in amidated pectin dried beads increased the endophytic activity by 10-fold. Moreover, plant promotion in radish plants enhanced by 18.9% and 20.7% for a dry matter of tuber and leaves. Confocal microscopy studies with GFP-tagged bacteria revealed that bacterial aggregates formed during the activation of beads play an essential role in early colonization stages. This research encourages the integration of fermentation and formulation strategies in a bioprocess engineering approach for exploiting endophytic bacteria.
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Affiliation(s)
- Mauricio Cruz Barrera
- Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA), Mosquera, Km 14 Bogotá-Mosquera, Colombia
| | - Desiree Jakobs-Schoenwandt
- WG Fermentation and Formulation of Biologicals and Chemicals, Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, Germany
| | - Martha Isabel Gómez
- Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA), Mosquera, Km 14 Bogotá-Mosquera, Colombia
| | - Juan Serrato
- National University, Chemical Engineering, Bogotá, Colombia
| | - Silke Ruppel
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany
| | - Anant V Patel
- WG Fermentation and Formulation of Biologicals and Chemicals, Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, Germany
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Zhang Y, Xu J, Wang E, Wang N. Mechanisms Underlying the Rhizosphere-To-Rhizoplane Enrichment of Cellvibrio Unveiled by Genome-Centric Metagenomics and Metatranscriptomics. Microorganisms 2020; 8:microorganisms8040583. [PMID: 32316533 PMCID: PMC7232360 DOI: 10.3390/microorganisms8040583] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 11/17/2022] Open
Abstract
Maintaining integrity of the plant cell walls is critical for plant health, however, our previous study showed that Cellvibrio, which is recognized by its robust ability to degrade plant cell walls, was enriched from the citrus rhizosphere to the rhizoplane (i.e., the root surface). Here we investigated the mechanisms underlying the rhizosphere-to-rhizoplane enrichment of Cellvibrio through genome-centric metagenomics and metatranscriptomics analyses. We recovered a near-complete metagenome-assembled genome representing a potentially novel species of Cellvibrio, herein designated Bin79, with genome size of 5.71 Mb across 11 scaffolds. Differential gene expression analysis demonstrated that plant cell wall degradation genes were repressed, whereas genes encoding chitin-degrading enzymes were induced in the rhizoplane compared with the rhizosphere. Enhanced expression of multi-drug efflux genes and iron acquisition- and storage-associated genes in the rhizoplane indicated mechanisms by which Bin79 competes with other microbes. In addition, genes involved in repelling plant immune responses were significantly activated in the rhizoplane. Comparative genomics analyses with five related Cellvibrio strains showed the importance of gene gain events for the rhizoplane adaptation of Bin79. Overall, this study characterizes a novel Cellvibrio strain and indicates the mechanisms involved in its adaptation to the rhizoplane from meta-omics data without cultivation.
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Affiliation(s)
- Yunzeng Zhang
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL 33850, USA;
- Correspondence: (Y.Z.); (N.W.); Tel.: +86-(514)-87971136 (Y.Z.); +1-(863)-9568829 (N.W.)
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL 33850, USA;
| | - Entao Wang
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, C. D. Mexico 11340, Mexico;
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL 33850, USA;
- Correspondence: (Y.Z.); (N.W.); Tel.: +86-(514)-87971136 (Y.Z.); +1-(863)-9568829 (N.W.)
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Wang Q, Gu J, Wang X, Ma J, Hu T, Peng H, Bao J, Zhang R. Effects of nano-zerovalent iron on antibiotic resistance genes and mobile genetic elements during swine manure composting. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113654. [PMID: 31806457 DOI: 10.1016/j.envpol.2019.113654] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 10/12/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Livestock manure is a reservoir for antibiotic resistance genes (ARGs), and aerobic composting is used widely for recycling animal manure. This study investigated the effects of adding nano-zerovalent iron (nZVI) at 0, 100, and 1000 mg/kg on the fates of ARGs and mobile genetic elements (MGEs) during swine manure composting. Under nZVI at 100 mg/kg, the relative abundances of sul1, sul2, dfrA7, ermF, and ermX decreased by 33.26-99.31% after composting, and the relative abundances of intI2 and Tn916/1545 decreased by 95.59% and 97.65%, respectively. Most of the ARGs and MGEs co-occurred and they had strong correlations with each other. The bacterial community structure was significantly separated by the composting periods, and they clustered together under different treatments in the same phase. Network analysis showed that Solibacillus, Clostridium_sensu_stricto_1, Terrisporobacter, Romboutsia, Turicibacter, Lactobacillus, Planococcus, Dietzia, and Corynebacterium_1 were common potential hosts of ARGs and MGEs. Redundancy analysis suggested that MGEs had key effects on the variations in the relative abundances of ARGs. Adding 100 mg/kg nZVI could reduce the environmental risk of ARGs by decreasing the abundances of MGEs.
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Affiliation(s)
- Qianzhi Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jie Gu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| | - Xiaojuan Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jiyue Ma
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ting Hu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Huiling Peng
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jianfeng Bao
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ranran Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
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High-throughput screening of environmental polysaccharide-degrading bacteria using biomass containment and complex insoluble substrates. Appl Microbiol Biotechnol 2020; 104:3379-3389. [PMID: 32114675 PMCID: PMC7089899 DOI: 10.1007/s00253-020-10469-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/12/2019] [Accepted: 02/12/2020] [Indexed: 11/08/2022]
Abstract
Carbohydrate degradation by microbes plays an important role in global nutrient cycling, human nutrition, and biotechnological applications. Studies that focus on the degradation of complex recalcitrant polysaccharides are challenging because of the insolubility of these substrates as found in their natural contexts. Specifically, current methods to examine carbohydrate-based biomass degradation using bacterial strains or purified enzymes are not compatible with high-throughput screening using complex insoluble materials. In this report, we developed a small 3D printed filter device that fits inside a microplate well that allows for the free movement of bacterial cells, media, and enzymes while containing insoluble biomass. These devices do not interfere with standard microplate readers and can be used for both short- (24–48 h) and long-duration (> 100 h) experiments using complex insoluble substrates. These devices were used to quantitatively screen in a high-throughput manner environmental isolates for their ability to grow using lignocellulose or rice grains as a sole nutrient source. Additionally, we determined that the microplate-based containment devices are compatible with existing enzymatic assays to measure activity against insoluble biomass. Overall, these microplate containment devices provide a platform to study the degradation of complex insoluble materials in a high-throughput manner and have the potential to help uncover ecologically important aspects of bacterial metabolism as well as to accelerate biotechnological innovation.
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López-Mondéjar R, Algora C, Baldrian P. Lignocellulolytic systems of soil bacteria: A vast and diverse toolbox for biotechnological conversion processes. Biotechnol Adv 2019; 37:107374. [DOI: 10.1016/j.biotechadv.2019.03.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/06/2019] [Accepted: 03/21/2019] [Indexed: 12/12/2022]
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Complete Genome Sequences of Cellvibrio japonicus Strains with Improved Growth When Using α-Diglucosides. Microbiol Resour Announc 2019; 8:8/44/e01077-19. [PMID: 31672746 PMCID: PMC6953504 DOI: 10.1128/mra.01077-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cellvibrio japonicus is a saprophytic bacterium that has been studied for its substantial carbohydrate degradation capability. We announce the genome sequences of three strains with improved growth characteristics when utilizing α-diglucosides. These data provide additional insight into the metabolic flexibility of a biotechnologically relevant bacterium. Cellvibrio japonicus is a saprophytic bacterium that has been studied for its substantial carbohydrate degradation capability. We announce the genome sequences of three strains with improved growth characteristics when utilizing α-diglucosides. These data provide additional insight into the metabolic flexibility of a biotechnologically relevant bacterium.
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Lillington SP, Leggieri PA, Heom KA, O'Malley MA. Nature's recyclers: anaerobic microbial communities drive crude biomass deconstruction. Curr Opin Biotechnol 2019; 62:38-47. [PMID: 31593910 DOI: 10.1016/j.copbio.2019.08.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/25/2019] [Accepted: 08/29/2019] [Indexed: 12/13/2022]
Abstract
Microbial communities within anaerobic ecosystems have evolved to degrade and recycle carbon throughout the earth. A number of strains have been isolated from anaerobic microbial communities, which are rich in carbohydrate active enzymes (CAZymes) to liberate fermentable sugars from crude plant biomass (lignocellulose). However, natural anaerobic communities host a wealth of microbial diversity that has yet to be harnessed for biotechnological applications to hydrolyze crude biomass into sugars and value-added products. This review highlights recent advances in 'omics' techniques to sequence anaerobic microbial genomes, decipher microbial membership, and characterize CAZyme diversity in anaerobic microbiomes. With a focus on the herbivore rumen, we further discuss methods to discover new CAZymes, including those found within multi-enzyme fungal cellulosomes. Emerging techniques to characterize the interwoven metabolism and spatial interactions between anaerobes are also reviewed, which will prove critical to developing a predictive understanding of anaerobic communities to guide in microbiome engineering.
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Affiliation(s)
- Stephen P Lillington
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, United States
| | - Patrick A Leggieri
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, United States
| | - Kellie A Heom
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, United States
| | - Michelle A O'Malley
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, United States.
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De novo genome assembly and comparative annotation reveals metabolic versatility in cellulolytic bacteria from cropland and forest soils. Funct Integr Genomics 2019; 20:89-101. [PMID: 31378834 DOI: 10.1007/s10142-019-00704-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 07/09/2019] [Accepted: 07/24/2019] [Indexed: 10/26/2022]
Abstract
Cellulose, the most abundant polysaccharide in nature, is a rich source of renewable energy and sustains soil nutrients. Among the microorganisms known to degrade cellulose, bacteria are less studied compared to fungi. In the present work, we have investigated the culturable bacteria actively involved in cellulose degradation in forest and crop field soils. Based on clear zone formation and enzyme activity assay, we identified 7 bacterial strains positive for cellulose degradation. Of these, two most efficient strains (Bacillus cereus strains BHU1 and BHU2) were selected for whole genome sequencing, annotation, and information regarding GC content, number of genes, total subsystems, starch, and cellulose degradation pathways. Average nucleotide identity (ANI) showed more than 90% similarity between both the strains (BHU1 and BHU2) and with B. cereus ATCC 14579. Both the strains have genes and enzyme families like endoglucanase and β-glucosidase as evident from whole genome sequence. Cellulase containing gene families (GH5, GH8, GH1), and many other carbohydrate-degrading enzymes, were present in both the bacterial strains. Taken together, the results suggest that the strains were efficient in cellulose degradation, and can be used for energy generation and production of value-added product.
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Arnal G, Stogios PJ, Asohan J, Attia MA, Skarina T, Viborg AH, Henrissat B, Savchenko A, Brumer H. Substrate specificity, regiospecificity, and processivity in glycoside hydrolase family 74. J Biol Chem 2019; 294:13233-13247. [PMID: 31324716 DOI: 10.1074/jbc.ra119.009861] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/16/2019] [Indexed: 12/11/2022] Open
Abstract
Glycoside hydrolase family 74 (GH74) is a historically important family of endo-β-glucanases. On the basis of early reports of detectable activity on cellulose and soluble cellulose derivatives, GH74 was originally considered to be a "cellulase" family, although more recent studies have generally indicated a high specificity toward the ubiquitous plant cell wall matrix glycan xyloglucan. Previous studies have indicated that GH74 xyloglucanases differ in backbone cleavage regiospecificities and can adopt three distinct hydrolytic modes of action: exo, endo-dissociative, and endo-processive. To improve functional predictions within GH74, here we coupled in-depth biochemical characterization of 17 recombinant proteins with structural biology-based investigations in the context of a comprehensive molecular phylogeny, including all previously characterized family members. Elucidation of four new GH74 tertiary structures, as well as one distantly related dual seven-bladed β-propeller protein from a marine bacterium, highlighted key structure-function relationships along protein evolutionary trajectories. We could define five phylogenetic groups, which delineated the mode of action and the regiospecificity of GH74 members. At the extremes, a major group of enzymes diverged to hydrolyze the backbone of xyloglucan nonspecifically with a dissociative mode of action and relaxed backbone regiospecificity. In contrast, a sister group of GH74 enzymes has evolved a large hydrophobic platform comprising 10 subsites, which facilitates processivity. Overall, the findings of our study refine our understanding of catalysis in GH74, providing a framework for future experimentation as well as for bioinformatics predictions of sequences emerging from (meta)genomic studies.
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Affiliation(s)
- Gregory Arnal
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Jathavan Asohan
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Mohamed A Attia
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Alexander Holm Viborg
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille University, 13007 Marseille, France; INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques (AFMB), 13007 Marseille, France
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta T2N 4N1, Canada.
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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Busch A, Danchin EGJ, Pauchet Y. Functional diversification of horizontally acquired glycoside hydrolase family 45 (GH45) proteins in Phytophaga beetles. BMC Evol Biol 2019; 19:100. [PMID: 31077129 PMCID: PMC6509783 DOI: 10.1186/s12862-019-1429-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/26/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cellulose, a major polysaccharide of the plant cell wall, consists of β-1,4-linked glucose moieties forming a molecular network recalcitrant to enzymatic breakdown. Although cellulose is potentially a rich source of energy, the ability to degrade it is rare in animals and was believed to be present only in cellulolytic microbes. Recently, it has become clear that some animals encode endogenous cellulases belonging to several glycoside hydrolase families (GHs), including GH45. GH45s are distributed patchily among the Metazoa and, in insects, are encoded only by the genomes of Phytophaga beetles. This study aims to understand both the enzymatic functions and the evolutionary history of GH45s in these beetles. RESULTS To this end, we biochemically assessed the enzymatic activities of 37 GH45s derived from five species of Phytophaga beetles and discovered that beetle-derived GH45s degrade three different substrates: amorphous cellulose, xyloglucan and glucomannan. Our phylogenetic and gene structure analyses indicate that at least one gene encoding a putative cellulolytic GH45 was present in the last common ancestor of the Phytophaga, and that GH45 xyloglucanases evolved several times independently in these beetles. The most closely related clade to Phytophaga GH45s was composed of fungal sequences, suggesting this GH family was acquired by horizontal gene transfer from fungi. Besides the insects, other arthropod GH45s do not share a common origin and appear to have emerged at least three times independently. CONCLUSION The rise of functional innovation from gene duplication events has been a fundamental process in the evolution of GH45s in Phytophaga beetles. Both, enzymatic activity and ancestral origin suggest that GH45s were likely an essential prerequisite for the adaptation allowing Phytophaga beetles to feed on plants.
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Affiliation(s)
- André Busch
- Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | | | - Yannick Pauchet
- Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany.
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Polysaccharide fractions from Fortunella margarita affect proliferation of Bifidobacterium adolescentis ATCC 15703 and undergo structural changes following fermentation. Int J Biol Macromol 2019; 123:1070-1078. [DOI: 10.1016/j.ijbiomac.2018.11.163] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/14/2018] [Accepted: 11/17/2018] [Indexed: 12/21/2022]
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Guo H, Gu J, Wang X, Tuo X, Yu J, Zhang R. Key role of cyromazine in the distribution of antibiotic resistance genes and bacterial community variation in aerobic composting. BIORESOURCE TECHNOLOGY 2019; 274:418-424. [PMID: 30553081 DOI: 10.1016/j.biortech.2018.12.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 11/25/2018] [Accepted: 12/01/2018] [Indexed: 06/09/2023]
Abstract
The risks that have not been noted so far have come from the use of non-antibiotics. In this study, non-antibiotic drug (cyromazine) was used in composting to investigate its possible effects on the distribution of ARGs and changes of bacterial community. Results showed that cyromazine increased the abundances of highly-risky ARGs (blaCTX-M and blaVIM), and heavy metal resistance genes (MRGs). Low and high concentrations of cyromazine increased the abundance of Tn916/1545 by 18.27% and 64.26%, respectively, compared with the control treatment. Mobile genetic elements (MGEs) and MRGs were not the major cause of the dynamic changes in ARGs, but instead the bacterial community succession changed according to the moisture content, pH, and bio-Cu. Network analysis showed that Proteobacteria and Actinobacteria were the major hosts for ARGs, and there was a significant correlation between tcrB, sul1 and Tn916/1545.
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Affiliation(s)
- Honghong Guo
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jie Gu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Xiaojuan Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaxia Tuo
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jing Yu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ranran Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
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Zhang H, Dong S, Lou T, Wang S. Complete genome sequence unveiled cellulose degradation enzymes and secondary metabolic potentials in Streptomyces sp. CC0208. J Basic Microbiol 2018; 59:267-276. [PMID: 30589093 DOI: 10.1002/jobm.201800563] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/19/2018] [Accepted: 11/30/2018] [Indexed: 11/10/2022]
Abstract
Marine Streptomyces sp. CC0208 isolated from the Bohai Bay showed high efficiency of cellulose degradation under optimized fermentation parameters. Also, as one of the bioinformatics-based approaches for the discovery of novel natural product and enzyme effectively, genome mining has been developed and applied widely. Herein, we reported the complete genome sequence of Streptomyces sp. CC0208.Whole-genome sequencing analysis revealed a genome size of 9,325,981 bp with a linear chromosome, GC content of 70.59% and 8487 protein-coding genes. Abundant genes have predicted functions in antibiotic metabolism and enzymes. A 20 enzymes closely associated with cellulose degradation were discovered. A total of 25 biosynthetic gene clusters (BGCs) of secondary metabolites were identified, including diverse classes of natural products. The availability of genome sequence of Streptomyces sp. CC0208 not only will assist in cracking the mechanism of cellulose degradation but also will provide the insights into the significant secondary metabolic potentials for the production of diverse compound classes based on rational strategies.
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Affiliation(s)
- Hongyu Zhang
- Tianjin Key Laboratory of Food Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China.,State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shirui Dong
- Tianjin Key Laboratory of Food Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Tingting Lou
- Tianjin Entry and Exit Inspection and Quarantine Bureau, Tianjin, China
| | - Suying Wang
- Tianjin Key Laboratory of Food Biotechnology, College of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
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Boncan DAT, David AME, Lluisma AO. A CAZyme-Rich Genome of a Taxonomically Novel Rhodophyte-Associated Carrageenolytic Marine Bacterium. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2018; 20:685-705. [PMID: 29936557 DOI: 10.1007/s10126-018-9840-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
Carbohydrate-active enzymes (CAZymes) have significant biotechnological potential as agents for degradation or modification of polysaccharides/glycans. As marine macroalgae are known to be rich in various types of polysaccharides, seaweed-associated bacteria are likely to be a good source of these CAZymes. A genomics approach can be used to explore CAZyme abundance and diversity, but it can also provide deep insights into the biology of CAZyme producers and, in particular, into molecular mechanisms that mediate their interaction with their hosts. In this study, a Gram-negative, aerobic, rod-shaped, carrageenolytic, and culturable marine bacterium designated as AOL6 was isolated from a diseased thallus of a carrageenan-producing farmed rhodophyte, Kappaphycus alvarezii (Gigartinales, Rhodophyta). The whole genome of this bacterium was sequenced and characterized. Sequence reads were assembled producing a high-quality genome assembly. The estimated genome size of the bacterium is 4.4 Mb and a G+C content of 52%. Molecular phylogenetic analysis based on a complete sequence of 16S rRNA, rpoB, and a set of 38 single-copy genes suggests that the bacterium is an unknown species and represents a novel genus in the family Cellvibrionaceae that is most closely related to the genera Teredinibacter and Saccharophagus. Genome comparison with T. turnerae T7901 and S. degradans 2-40 reveals several features shared by the three species, including a large number of CAZymes that comprised > 5% of the total number of protein-coding genes. The high proportion of CAZymes found in the AOL6 genome exceeds that of other known carbohydrate degraders, suggesting a significant capacity to degrade a range of polysaccharides including κ-carrageenan; 34% of these CAZymes have signal peptide sequences for secretion. Three putative κ-carrageenase-encoding genes were identified from the genome of the bacterium via in silico analysis, consistent with the results of the zymography assay (with κ-carrageenan as substrate). Genome analysis also indicated that AOL6 relies exclusively on type 2 secretion system (T2SS) for secreting proteins (possibly including glycoside hydrolases). In relation to T2SS, the product of the pilZ gene was predicted to be highly expressed, suggesting specialization for cell adhesion and secretion of virulence factors. The assignment of proteins to clusters of orthologous groups (COGs) revealed a pattern characteristic of r-strategists. Majority of two-component system proteins identified in the AOL6 genome were also predicted to be involved in chemotaxis and surface colonization. These genomic features suggest that AOL6 is an opportunistic pathogen, adapted to colonizing polysaccharide-rich hosts, including carrageenophytes.
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Affiliation(s)
- Delbert Almerick T Boncan
- Marine Science Institute, College of Science, University of the Philippines Diliman, 1101, Quezon City, Philippines
- National Institute of Molecular Biology and Biotechnology, College of Science, University of the Philippines Diliman, 1101, Quezon City, Philippines
| | - Anne Marjorie E David
- Marine Science Institute, College of Science, University of the Philippines Diliman, 1101, Quezon City, Philippines
- Institute of Biology, College of Science, University of the Philippines Diliman, 1101, Quezon City, Philippines
| | - Arturo O Lluisma
- Marine Science Institute, College of Science, University of the Philippines Diliman, 1101, Quezon City, Philippines.
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Cai L, Gong X, Sun X, Li S, Yu X. Comparison of chemical and microbiological changes during the aerobic composting and vermicomposting of green waste. PLoS One 2018; 13:e0207494. [PMID: 30475832 PMCID: PMC6261053 DOI: 10.1371/journal.pone.0207494] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/30/2018] [Indexed: 01/01/2023] Open
Abstract
This research was conducted to compare chemical and microbiological properties during aerobic composting (AC) and vermicomposting (VC) of green waste. Relative to AC, VC significantly decreased the pH and lignin and cellulose contents, and significantly increased the electrical conductivity and total N and available P contents. For AC, BIrii41_norank (order Myxococcales) was the major bacterial genus at 30 d and again became dominant genus from 90–150 d, with relative abundances of 2.88% and 4.77–5.19%, respectively; at 45 d and 60 d, the dominant bacterial genus was Nitrosomonadaceae_uncultured (order Nitrosomonadales) with relative abundances of 2.83–7.17%. For VC, the dominant bacterial genus was BIrii41_norank (except at 45 d), which accounted for 2.11–7.96% of the total reads. The dominant fungal class was Sordariomycetes in AC (relative abundances 39.2–80.6%) and VC (relative abundances 42.1–69.5%). The abundances of microbial taxa and therefore the bacterial and fungal community structures differed between VC and AC. The quality of the green waste compost product was higher with VC than with AC. These results will also help to achieve further composting technology breakthroughs in reducing the composting time and improving compost quality.
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Affiliation(s)
- Linlin Cai
- College of Forestry, Beijing Forestry University, Beijing, P.R. China
| | - Xiaoqiang Gong
- College of Forestry, Beijing Forestry University, Beijing, P.R. China
| | - Xiangyang Sun
- College of Forestry, Beijing Forestry University, Beijing, P.R. China
| | - Suyan Li
- College of Forestry, Beijing Forestry University, Beijing, P.R. China
| | - Xin Yu
- College of Forestry, Beijing Forestry University, Beijing, P.R. China
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