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Yan J, Guo X, Li Q, Yuan X, Zhang Z, Tremblay LA, Li Z. Biochar derivation at low temperature: A novel strategy for harmful resource usage of antibiotic mycelial dreg. ENVIRONMENTAL RESEARCH 2024; 250:118376. [PMID: 38354891 DOI: 10.1016/j.envres.2024.118376] [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: 10/30/2023] [Revised: 01/14/2024] [Accepted: 01/29/2024] [Indexed: 02/16/2024]
Abstract
Antibiotic mycelial dreg (AMD) has been categorized as hazardous waste due to the high residual hazardous contaminants. Inappropriate management and disposal of AMD can cause potential environmental and ecological risks. In this study, the potential of pleuromutilin mycelial dreg (PMD) as a novel feedstock for preparing tetracycline hydrochloride (TC) adsorbent was explored to achieve safe management of PMD. The results suggested that residual hazardous contaminants were completely eliminated after pyrolysis. With the increase of pyrolysis temperature, the yields, H/C, O/C, (O + N)/C, and pore size in PMD-derived biochars (PMD-BCs) decreased, while BET surface area and pore volume increased, resulting in the higher stability of the PMD-BCs prepared from higher temperatures. The TC adsorption of the PMD-BCs increased from 27.3 to 46.9 mg/g with the increase of the pyrolysis temperature. Surprisingly, pH value had a strong impact on the TC adsorption, the adsorption capacity of BC-450 increased from 6.5 to 71.1 mg/g when the solution pH value increased from 2 to 10. Lewis acid-base interaction, pore filling, π-π interaction, hydrophobic interaction, and charge-assisted hydrogen bond (CAHB) are considered to drive the adsorption. This work provides a novel pathway for the concurrent detoxification and reutilization of AMD.
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Affiliation(s)
- Jing Yan
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, The Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xueqi Guo
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, The Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Qingjie Li
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, The Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xufeng Yuan
- College of Agronomy and Biotechnology, China Agriculture University, Beijing, 100193, China
| | - Zhenghai Zhang
- Shandong Shengli Bioengineering Co., LTD., Jining, 272000, Shandong, China
| | - Louis A Tremblay
- Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand; School of Biological Sciences, University of Auckland, PO Box 92019, Auckland, 1142, New Zealand
| | - Zhaojun Li
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, The Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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Yang Z, Chen X, Yu M, Jing R, Bao L, Zhao X, Pan K, Chao B, Qu M. Metagenomic sequencing identified microbial species in the rumen and cecum microbiome responsible for niacin treatment and related to intramuscular fat content in finishing cattle. Front Microbiol 2024; 15:1334068. [PMID: 38529181 PMCID: PMC10961399 DOI: 10.3389/fmicb.2024.1334068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/27/2024] [Indexed: 03/27/2024] Open
Abstract
Introduction Niacin is one of the essential vitamins for mammals. It plays important roles in maintaining rumen microecological homeostasis. Our previous study indicated that dietary niacin significantly elevated intramuscular fat content (IMF) in castrated finishing steers. Whether niacin affects fat deposition by regulating the microbial composition and functional capacities of gastrointestinal microbiome has been unknown yet. Methods In this study, 16 castrated Xiangzhong Black cattle were randomly assigned into either control group fed with a basal concentrate diet (n = 8) or niacin group fed with a basal concentrate diet added 1000 mg/kg niacin (n = 8). Seven rumen samples and five cecum content samples were randomly collected from each of control and niacin groups for metagenomic sequencing analysis. Results A total of 2,981,786 non-redundant microbial genes were obtained from all tested samples. Based on this, the phylogenetic compositions of the rumen and cecum microbiome were characterized. We found that bacteria dominated the rumen and cecum microbiome. Prevotella ruminicola and Ruminococcus flavefaciens were the most abundant bacterial species in the rumen microbiome, while Clostridiales bacterium and Eubacterium rectale were predominant bacterial species in the cecum microbiome. Rumen microbiome had significantly higher abundances of GHs, GTs, and PLs, while cecum microbiome was enriched by CBMs and AAs. We found a significant effect of dietary niacin on rumen microbiome, but not on cecum microbiome. Dietary niacin up-regulated the abundances of bacterial species producing lactic acid and butyrate, fermenting lactic acid, and participating in lipid hydrolysis, and degradation and assimilation of nitrogen-containing compounds, but down-regulated the abundances of several pathogens and bacterial species involved in the metabolism of proteins and peptides, and methane emissions. From the correlation analysis, we suggested that niacin improved nutrient digestion and absorption, but reduced energy loss, and Valine, leucine and isoleucine degradation of rumen microbiome, which resulted in the increased host IMF. Conclusion The results suggested that dietary manipulation, such as the supplementation of niacin, should be regarded as the effective and convenient way to improve IMF of castrated finishing steers by regulating rumen microbiome.
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Affiliation(s)
- Zhuqing Yang
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, China
| | - Xiao Chen
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Mingjin Yu
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Ruixue Jing
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Linbin Bao
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, China
- Animal Husbandry and Veterinary Bureau of Guangchang County, Fuzhou, China
| | - Xianghui Zhao
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, China
| | - Ke Pan
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, China
| | - Bihui Chao
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Mingren Qu
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, China
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Silale A, Zhu Y, Witwinowski J, Smith RE, Newman KE, Bhamidimarri SP, Baslé A, Khalid S, Beloin C, Gribaldo S, van den Berg B. Dual function of OmpM as outer membrane tether and nutrient uptake channel in diderm Firmicutes. Nat Commun 2023; 14:7152. [PMID: 37932269 PMCID: PMC10628300 DOI: 10.1038/s41467-023-42601-y] [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: 02/10/2023] [Accepted: 10/16/2023] [Indexed: 11/08/2023] Open
Abstract
The outer membrane (OM) in diderm, or Gram-negative, bacteria must be tethered to peptidoglycan for mechanical stability and to maintain cell morphology. Most diderm phyla from the Terrabacteria group have recently been shown to lack well-characterised OM attachment systems, but instead have OmpM, which could represent an ancestral tethering system in bacteria. Here, we have determined the structure of the most abundant OmpM protein from Veillonella parvula (diderm Firmicutes) by single particle cryogenic electron microscopy. We also characterised the channel properties of the transmembrane β-barrel of OmpM and investigated the structure and PG-binding properties of its periplasmic stalk region. Our results show that OM tethering and nutrient acquisition are genetically linked in V. parvula, and probably other diderm Terrabacteria. This dual function of OmpM may have played a role in the loss of the OM in ancestral bacteria and the emergence of monoderm bacterial lineages.
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Affiliation(s)
- Augustinas Silale
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, NE2 4HH, Newcastle upon Tyne, UK
| | - Yiling Zhu
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, NE2 4HH, Newcastle upon Tyne, UK
| | - Jerzy Witwinowski
- Institut Pasteur, Université de Paris Cité, Unit Evolutionary Biology of the Microbial Cell, Paris, France
| | - Robert E Smith
- Institut Pasteur, Université de Paris Cité, Unit Evolutionary Biology of the Microbial Cell, Paris, France
| | - Kahlan E Newman
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Satya P Bhamidimarri
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, NE2 4HH, Newcastle upon Tyne, UK
| | - Arnaud Baslé
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, NE2 4HH, Newcastle upon Tyne, UK
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Christophe Beloin
- Institut Pasteur, Université de Paris Cité, Genetics of Biofilms Laboratory, Paris, France.
| | - Simonetta Gribaldo
- Institut Pasteur, Université de Paris Cité, Unit Evolutionary Biology of the Microbial Cell, Paris, France.
| | - Bert van den Berg
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, NE2 4HH, Newcastle upon Tyne, UK.
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4
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von Kügelgen A, van Dorst S, Alva V, Bharat TAM. A multidomain connector links the outer membrane and cell wall in phylogenetically deep-branching bacteria. Proc Natl Acad Sci U S A 2022; 119:e2203156119. [PMID: 35943982 PMCID: PMC9388160 DOI: 10.1073/pnas.2203156119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 06/24/2022] [Indexed: 01/30/2023] Open
Abstract
Deinococcus radiodurans is a phylogenetically deep-branching extremophilic bacterium that is remarkably tolerant to numerous environmental stresses, including large doses of ultraviolet (UV) radiation and extreme temperatures. It can even survive in outer space for several years. This endurance of D. radiodurans has been partly ascribed to its atypical cell envelope comprising an inner membrane, a large periplasmic space with a thick peptidoglycan (PG) layer, and an outer membrane (OM) covered by a surface layer (S-layer). Despite intense research, molecular principles governing envelope organization and OM stabilization are unclear in D. radiodurans and related bacteria. Here, we report a electron cryomicroscopy (cryo-EM) structure of the abundant D. radiodurans OM protein SlpA, showing how its C-terminal segment forms homotrimers of 30-stranded β-barrels in the OM, whereas its N-terminal segment forms long, homotrimeric coiled coils linking the OM to the PG layer via S-layer homology (SLH) domains. Furthermore, using protein structure prediction and sequence-based bioinformatic analysis, we show that SlpA-like putative OM-PG connector proteins are widespread in phylogenetically deep-branching Gram-negative bacteria. Finally, combining our atomic structures with fluorescence and electron microscopy of cell envelopes of wild-type and mutant bacterial strains, we report a model for the cell surface of D. radiodurans. Our results will have important implications for understanding the cell surface organization and hyperstability of D. radiodurans and related bacteria and the evolutionary transition between Gram-negative and Gram-positive bacteria.
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Affiliation(s)
- Andriko von Kügelgen
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Sofie van Dorst
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen 72076, Germany
| | - Tanmay A. M. Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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5
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An ancient divide in outer membrane tethering systems in bacteria suggests a mechanism for the diderm-to-monoderm transition. Nat Microbiol 2022; 7:411-422. [PMID: 35246664 DOI: 10.1038/s41564-022-01066-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 01/24/2022] [Indexed: 11/08/2022]
Abstract
Recent data support the hypothesis that Gram-positive bacteria (monoderms) arose from Gram-negative ones (diderms) through loss of the outer membrane (OM), but how this happened remains unknown. As tethering of the OM is essential for cell envelope stability in diderm bacteria, its destabilization may have been involved in this transition. In the present study, we present an in-depth analysis of the four known main OM-tethering systems across the Tree of Bacteria (ToB). We show that the presence of such systems follows the ToB with a bimodal distribution matching the deepest phylogenetic divergence between Terrabacteria and Gracilicutes. Whereas the lipoprotein peptidoglycan-associated lipoprotein (Pal) is restricted to the Gracilicutes, along with a more sporadic occurrence of OmpA, and Braun's lipoprotein is present only in a subclade of Gammaproteobacteria, diderm Terrabacteria display, as the main system, the OmpM protein. We propose an evolutionary scenario whereby OmpM represents a simple, ancestral OM-tethering system that was later replaced by one based on Pal after the emergence of the Lol machinery to deliver lipoproteins to the OM, with OmpA as a possible transition state. We speculate that the existence of only one main OM-tethering system in the Terrabacteria would have allowed the multiple OM losses specifically inferred in this clade through OmpM perturbation, and we provide experimental support for this hypothesis by inactivating all four ompM gene copies in the genetically tractable diderm Firmicute Veillonella parvula. High-resolution imaging and tomogram reconstructions reveal a non-lethal phenotype in which vast portions of the OM detach from the cells, forming huge vesicles with an inflated periplasm shared by multiple dividing cells. Together, our results highlight an ancient shift of OM-tethering systems in bacterial evolution and suggest a mechanism for OM loss and the multiple emergences of the monoderm phenotype from diderm ancestors.
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Maki JJ, Looft T. Megasphaera stantonii sp. nov., a butyrate-producing bacterium isolated from the cecum of a healthy chicken. Int J Syst Evol Microbiol 2018; 68:3409-3415. [PMID: 30281016 DOI: 10.1099/ijsem.0.002991] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A novel mesophilic, anaerobic, Gram-stain-negative bacterium was isolated from the cecum of a healthy white leghorn chicken, and designated AJH120T. Cells were coccoid or diplococcoid with an average size of 0.8-1.8 µm and were non-motile with no evidence of spores. Phylogenetic analysis of 16S rRNA gene sequences revealed this organism to be a member of the genus Megasphaera, with the closest relatives being Megasphaera elsdenii (95 % sequence identity) and Megasphaera cerevisiae (95 % sequence identity). Growth was observed between 30 and 50 °C and between pH 5.0 and 9.0. AJH120T utilized a variety of carbon sources, including succinate, gluconate, fructose, ribose and pyruvate, as well as many individual amino acids. The DNA G+C content for the genome sequence of AJH120T was 52.1 mol%. Digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI) and average amino acid identity (AAI) between AJH120T and close taxonomic relatives, indicated divergence consistent with the strain representing a novel species. The major fatty acid methyl esters of the organism were C12 : 0, C14 : 0 3-OH, C18 : 1ω9c, C16 : 0 and C16 : 1ω9c. AJH120T was able to produce several short chain fatty acids, including butyrate, acetate, propionate and isovalerate. Together, these data indicate that AJH120T represents a novel species within the genus Megasphaera. We propose the name Megasphaerastantonii sp. nov. for the species. The type strain of this species is AJH120T (=DSM 106750T=CCUG 71842T).
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Affiliation(s)
- Joel J Maki
- 1United States Department of Agriculture, Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, 1920 Dayton Ave Ames IA 50010, USA.,2Interdepartmental Microbiology Graduate Program, Iowa State University, Ames IA 50011, USA
| | - Torey Looft
- 1United States Department of Agriculture, Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, 1920 Dayton Ave Ames IA 50010, USA
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7
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Antunes LC, Poppleton D, Klingl A, Criscuolo A, Dupuy B, Brochier-Armanet C, Beloin C, Gribaldo S. Phylogenomic analysis supports the ancestral presence of LPS-outer membranes in the Firmicutes. eLife 2016; 5. [PMID: 27580370 PMCID: PMC5007114 DOI: 10.7554/elife.14589] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 07/21/2016] [Indexed: 12/22/2022] Open
Abstract
One of the major unanswered questions in evolutionary biology is when and how the transition between diderm (two membranes) and monoderm (one membrane) cell envelopes occurred in Bacteria. The Negativicutes and the Halanaerobiales belong to the classically monoderm Firmicutes, but possess outer membranes with lipopolysaccharide (LPS-OM). Here, we show that they form two phylogenetically distinct lineages, each close to different monoderm relatives. In contrast, their core LPS biosynthesis enzymes were inherited vertically, as in the majority of bacterial phyla. Finally, annotation of key OM systems in the Halanaerobiales and the Negativicutes shows a puzzling combination of monoderm and diderm features. Together, these results support the hypothesis that the LPS-OMs of Negativicutes and Halanaerobiales are remnants of an ancient diderm cell envelope that was present in the ancestor of the Firmicutes, and that the monoderm phenotype in this phylum is a derived character that arose multiple times independently through OM loss. DOI:http://dx.doi.org/10.7554/eLife.14589.001 The cell envelope is one of the evolutionarily oldest parts of a bacterium. This structure – made up of a cell wall and either one or two cell membranes – surrounds the bacterial cell, maintaining the cell’s structure and providing an interface through which bacteria can sense their environment and communicate. Bacteria can be broadly classed based on the number of cell membranes that their envelope consists of. Bacteria that have a single cell membrane are known as “monoderm”, whereas those with two membranes are termed “diderm”. The number of membranes that bacteria have can affect how well they resist antibacterial compounds. When, how and why bacteria switched between monoderm and diderm cell envelopes are some of the major unanswered questions in evolutionary biology. The textbook example of a monoderm cell envelope can be found in bacteria called Firmicutes. This group includes some notoriously harmful bacteria such as Staphylococcus, which can cause conditions ranging from abscesses to pneumonia. However, some Firmicutes possess two cell membranes. It was unclear how these unusual diderm Firmicutes developed a second membrane, and how they are related to their monoderm relatives. Antunes, Poppleton et al. set out to answer these questions by analyzing the information contained in the thousands of bacterial genomes that have already been described. The results indicate that Firmicutes originally had diderm envelopes, and that species with monoderm envelopes arose independently several times through the loss of their outermost membrane. Future work is needed to investigate the driving forces and the precise mechanism that led most Firmicutes to lose their outer membrane. Also, further characterization of diderm Firmicutes will provide key information about the biology of these poorly understood bacteria. DOI:http://dx.doi.org/10.7554/eLife.14589.002
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Affiliation(s)
- Luisa Cs Antunes
- Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France
| | - Daniel Poppleton
- Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France
| | - Andreas Klingl
- Plant Development and Electron Microscopy, Department of Biology I, Biocenter LMU, Munich, Germany
| | - Alexis Criscuolo
- Bioinformatics and Biostatistics Hub, Institut Pasteur, Paris, France
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, Département de Microbiologie, Institut Pasteur, Paris
| | | | - Christophe Beloin
- Unité de Génétique des Biofilms, Département de Microbiologie, Institut Pasteur, Paris, France
| | - Simonetta Gribaldo
- Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France
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Kojima S, Hayashi K, Tochigi S, Kusano T, Kaneko J, Kamio Y. Peptidoglycan-associated outer membrane protein Mep45 of rumen anaerobe Selenomonas ruminantium forms a non-specific diffusion pore via its C-terminal transmembrane domain. Biosci Biotechnol Biochem 2016; 80:1954-9. [PMID: 27310312 PMCID: PMC5020339 DOI: 10.1080/09168451.2016.1194185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The major outer membrane protein Mep45 of Selenomonas ruminantium, an anaerobic Gram-negative bacterium, comprises two distinct domains: the N-terminal S-layer homologous (SLH) domain that protrudes into the periplasm and binds to peptidoglycan, and the remaining C-terminal transmembrane domain, whose function has been unknown. Here, we solubilized and purified Mep45 and characterized its function using proteoliposomes reconstituted with Mep45. We found that Mep45 forms a nonspecific diffusion channel via its C-terminal region. The channel was permeable to solutes smaller than a molecular weight of roughly 600, and the estimated pore radius was 0.58 nm. Truncation of the SLH domain did not affect the channel property. On the basis of the fact that Mep45 is the most abundant outer membrane protein in S. ruminantium, we conclude that Mep45 serves as a main pathway through which small solutes diffuse across the outer membrane of this bacterium.
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Affiliation(s)
- Seiji Kojima
- a Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , Sendai , Japan.,b Graduate School of Life Sciences , Tohoku University , Sendai , Japan
| | - Kanako Hayashi
- c Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Saeko Tochigi
- b Graduate School of Life Sciences , Tohoku University , Sendai , Japan
| | - Tomonobu Kusano
- b Graduate School of Life Sciences , Tohoku University , Sendai , Japan
| | - Jun Kaneko
- c Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Yoshiyuki Kamio
- c Graduate School of Agricultural Science , Tohoku University , Sendai , Japan.,d Graduate School of Comprehensive Human Sciences , Shokei-Gakuin University , Natori , Japan
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9
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Reddy BL, Saier MH. Properties and Phylogeny of 76 Families of Bacterial and Eukaryotic Organellar Outer Membrane Pore-Forming Proteins. PLoS One 2016; 11:e0152733. [PMID: 27064789 PMCID: PMC4827864 DOI: 10.1371/journal.pone.0152733] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/18/2016] [Indexed: 12/11/2022] Open
Abstract
We here report statistical analyses of 76 families of integral outer membrane pore-forming proteins (OMPPs) found in bacteria and eukaryotic organelles. 47 of these families fall into one superfamily (SFI) which segregate into fifteen phylogenetic clusters. Families with members of the same protein size, topology and substrate specificities often cluster together. Virtually all OMPP families include only proteins that form transmembrane pores. Nine such families, all of which cluster together in the SFI phylogenetic tree, contain both α- and β-structures, are multi domain, multi subunit systems, and transport macromolecules. Most other SFI OMPPs transport small molecules. SFII and SFV homologues derive from Actinobacteria while SFIII and SFIV proteins derive from chloroplasts. Three families of actinobacterial OMPPs and two families of eukaryotic OMPPs apparently consist primarily of α-helices (α-TMSs). Of the 71 families of (putative) β-barrel OMPPs, only twenty could not be assigned to a superfamily, and these derived primarily from Actinobacteria (1), chloroplasts (1), spirochaetes (8), and proteobacteria (10). Proteins were identified in which two or three full length OMPPs are fused together. Family characteristic are described and evidence agrees with a previous proposal suggesting that many arose by adjacent β-hairpin structural unit duplications.
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Affiliation(s)
- Bhaskara L. Reddy
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California, United States of America
| | - Milton H. Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California, United States of America
- * E-mail:
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10
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Gorman-Lewis D, Martens-Habbena W, Stahl DA. Thermodynamic characterization of proton-ionizable functional groups on the cell surfaces of ammonia-oxidizing bacteria and archaea. GEOBIOLOGY 2014; 12:157-171. [PMID: 24589203 DOI: 10.1111/gbi.12075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 12/16/2013] [Indexed: 06/03/2023]
Abstract
The ammonia-oxidizing archaeon Nitrosopumilus maritimus strain SCM1 (strain SCM1), a representative of the Thaumarchaeota archaeal phylum, can sustain high specific rates of ammonia oxidation at ammonia concentrations too low to sustain metabolism by ammonia-oxidizing bacteria (AOB). One structural and biochemical difference between N. maritimus and AOB that might be related to the oligotrophic adaptation of strain SCM1 is the cell surface. A proteinaceous surface layer (S-layer) comprises the outermost boundary of the strain SCM1 cell envelope, as opposed to the lipopolysaccharide coat of Gram-negative AOB. In this work, we compared the surface reactivities of two archaea having an S-layer (strain SCM1 and Sulfolobus acidocaldarius) with those of four representative AOB (Nitrosospira briensis, Nitrosomonas europaea, Nitrosolobus multiformis, and Nitrosococcus oceani) using potentiometric and calorimetric titrations to evaluate differences in proton-ionizable surface sites. Strain SCM1 and S. acidocaldarius have a wider range of proton buffering (approximately pH 10-3.5) than the AOB (approximately pH 10-4), under the conditions investigated. Thermodynamic parameters describing proton-ionizable sites (acidity constants, enthalpies, and entropies of protonation) are consistent with these archaea having proton-ionizable amino acid side chains containing carboxyl, imidazole, thiol, hydroxyl, and amine functional groups. Phosphorous-bearing acidic functional groups, which might also be present, could be masked by imidazole and thiol functional groups. Parameters for the AOB are consistent with surface structures containing anionic oxygen ligands (carboxyl- and phosphorous-bearing acidic functional groups), thiols, and amines. In addition, our results showed that strain SCM1 has more reactive surface sites than the AOB and a high concentration of sites consistent with aspartic and/or glutamic acid. Because these alternative boundary layers mediate interaction with the local external environment, these data provide the basis for further comparisons of the thermodynamic behavior of surface reactivity toward essential nutrients.
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Affiliation(s)
- D Gorman-Lewis
- University of Washington, Department of Earth and Space Sciences, Seattle, WA, USA
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11
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Hypothetical Proteins Present During Recovery Phase of Radiation Resistant Bacterium Deinococcus radiodurans are Under Purifying Selection. J Mol Evol 2013; 77:31-42. [DOI: 10.1007/s00239-013-9577-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/26/2013] [Indexed: 01/15/2023]
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First report of mefA and msrA/msrB multidrug efflux pumps associated with blaTEM-1 β-lactamase in Enterococcus faecalis. Int J Infect Dis 2011; 16:e104-9. [PMID: 22137270 DOI: 10.1016/j.ijid.2011.09.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 09/22/2011] [Accepted: 09/30/2011] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES Enterococcus faecalis is thought to possess a great deal of intrinsic resistance to several antimicrobial agents. In this study we identified ampicillin- and erythromycin-resistant clinical isolates of E. faecalis and sought to identify the resistance mechanisms among these isolates. METHODS Twelve isolates of E. faecalis were collected from 12 different patients. Identification of the isolates and their susceptibility patterns were determined using the Phoenix automated phenotypic identification criteria. PCR amplification and sequencing were used to detect β-lactamase production. Colony blotting was performed in order to screen for multidrug efflux pump production. Extraction and N-terminal sequencing of the multidrug efflux pumps was carried out. RESULTS The E. faecalis isolates showed high resistance to erythromycin and ampicillin, with minimum inhibitory concentrations of >16 μg/ml. PCR amplification and sequencing showed that isolates produced TEM-1 β-lactamase. Colony blotting showed that these isolates harbored multidrug efflux pump genes. Multidrug efflux pump extraction, purification, and sequencing showed the distribution of mefA and msrA/msrB efflux pumps. CONCLUSION Two resistance mechanisms among E. faecalis are described - the production of TEM β-lactamase and mefA and msrA/msrB efflux pumps. These results are of great interest because this is the first report of the co-existence of these resistance mechanisms among E. faecalis strains.
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Cadaverine covalently linked to peptidoglycan is required for interaction between the peptidoglycan and the periplasm-exposed S-layer-homologous domain of major outer membrane protein Mep45 in Selenomonas ruminantium. J Bacteriol 2010; 192:5953-61. [PMID: 20851903 DOI: 10.1128/jb.00417-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The peptidoglycan of Selenomonas ruminantium is covalently bound to cadaverine (PG-cadaverine), which likely plays a significant role in maintaining the integrity of the cell surface structure. The outer membrane of this bacterium contains a 45-kDa major protein (Mep45) that is a putative peptidoglycan-associated protein. In this report, we determined the nucleotide sequence of the mep45 gene and investigated the relationship between PG-cadaverine, Mep45, and the cell surface structure. Amino acid sequence analysis showed that Mep45 is comprised of an N-terminal S-layer-homologous (SLH) domain followed by α-helical coiled-coil region and a C-terminal β-strand-rich region. The N-terminal SLH domain was found to be protruding into the periplasmic space and was responsible for binding to peptidoglycan. It was determined that Mep45 binds to the peptidoglycan in a manner dependent on the presence of PG-cadaverine. Electron microscopy revealed that defective PG-cadaverine decreased the structural interactions between peptidoglycan and the outer membrane, consistent with the proposed role for PG-cadaverine. The C-terminal β-strand-rich region of Mep45 was predicted to be a membrane-bound unit of the 14-stranded β-barrel structure. Here we propose that PG-cadaverine possesses functional importance to facilitate the structural linkage between peptidoglycan and the outer membrane via specific interaction with the SLH domain of Mep45.
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