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Hung YH, Lai HH, Lin HC, Sun KS, Chen CY. Investigating Factors of False-Positive Results of Aspergillus Galactomannan Assay: A Case-Control Study in Intensive Care Units. Front Pharmacol 2021; 12:747280. [PMID: 34987388 PMCID: PMC8721279 DOI: 10.3389/fphar.2021.747280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/08/2021] [Indexed: 12/12/2022] Open
Abstract
Background: Studies on false-positive galactomannan (GM) enzyme immunoassay (EIA) results and treatment for critically ill patients are scarce. Objectives: The study aimed to determine the false-positive rate of GM-EIA and to probe the risk factors of false positivity among patients in the intensive care units (ICUs). Methods: A case-control approach was conducted to review adult patients who had at least one GM-EIA result and were admitted to the ICU. Those who had no fungal culture were excluded. The clinical characteristics and critical care between patients with false-positive and true-negative GM index (GMI) were compared. Results: Of 206 patients enrolled and with GM-EIA results, 20 (9.7%) were considered to have false-positive antigenemia, including 9 in bronchoalveolar lavages (BAL) and 11 in serum. A total of 148 (71.8%) were true-negatives. After paired grouping of 1:4, factors researched in the previous studies showed no significant difference. However, compared with the true-negatives, patients with positive GM test results but were incompatible with the diagnosis of invasive aspergillosis were more prone to the risk of false positivity due to the use of colistin inhalation. It seemed to be the only factor that significantly increased the risk of false positivity after multivariate analysis (adjusted odds ratio, 35.68; 95% CI, 3.77-337.51, p = 0.002). Conclusions: Colistin inhalation treatment may contribute to false-positive GM-EIA results. The positive GMI among patients receiving colistin nebulization should be interpreted with caution.
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Affiliation(s)
- Yu-Hsuan Hung
- Department of Pharmacy, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
- School of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hui-Hsiung Lai
- Department of Pharmacy, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
| | - Hui-Chuan Lin
- Department of Pharmacy, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
| | - Kuo-Shao Sun
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, St. Martin De Porres Hospital, Chiayi, Taiwan
- Chung-Jen Junior College of Nursing, Health Sciences and Management, Chiayi, Taiwan
| | - Chung-Yu Chen
- School of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan
- Chung-Jen Junior College of Nursing, Health Sciences and Management, Chiayi, Taiwan
- Department of Pharmacy, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Center for Big Data Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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Metabolic capabilities mute positive response to direct and indirect impacts of warming throughout the soil profile. Nat Commun 2021; 12:2089. [PMID: 33828081 PMCID: PMC8027381 DOI: 10.1038/s41467-021-22408-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 03/10/2021] [Indexed: 02/01/2023] Open
Abstract
Increasing global temperatures are predicted to stimulate soil microbial respiration. The direct and indirect impacts of warming on soil microbes, nevertheless, remain unclear. This is particularly true for understudied subsoil microbes. Here, we show that 4.5 years of whole-profile soil warming in a temperate mixed forest results in altered microbial community composition and metabolism in surface soils, partly due to carbon limitation. However, microbial communities in the subsoil responded differently to warming than in the surface. Throughout the soil profile-but to a greater extent in the subsoil-physiologic and genomic measurements show that phylogenetically different microbes could utilize complex organic compounds, dampening the effect of altered resource availability induced by warming. We find subsoil microbes had 20% lower carbon use efficiencies and 47% lower growth rates compared to surface soils, which constrain microbial communities. Collectively, our results show that unlike in surface soils, elevated microbial respiration in subsoils may continue without microbial community change in the near-term.
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Lupinus albus γ-Conglutin, a Protein Structurally Related to GH12 Xyloglucan-Specific Endo-Glucanase Inhibitor Proteins (XEGIPs), Shows Inhibitory Activity against GH2 β-Mannosidase. Int J Mol Sci 2020; 21:ijms21197305. [PMID: 33022933 PMCID: PMC7583008 DOI: 10.3390/ijms21197305] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022] Open
Abstract
γ-conglutin (γC) is a major protein of Lupinus albus seeds, but its function is still unknown. It shares high structural similarity with xyloglucan-specific endo-glucanase inhibitor proteins (XEGIPs) and, to a lesser extent, with Triticum aestivum endoxylanase inhibitors (TAXI-I), active against fungal glycoside hydrolases GH12 and GH11, respectively. However, γC lacks both these inhibitory activities. Since β-galactomannans are major components of the cell walls of endosperm in several legume plants, we tested the inhibitory activity of γC against a GH2 β-mannosidase (EC 3.2.1.25). γC was actually able to inhibit the enzyme, and this effect was enhanced by the presence of zinc ions. The stoichiometry of the γC/enzyme interaction was 1:1, and the calculated Ki was 1.55 μM. To obtain further insights into the interaction between γC and β-mannosidase, an in silico structural bioinformatic approach was followed, including some docking analyses. By and large, this work describes experimental findings that highlight new scenarios for understanding the natural role of γC. Although structural predictions can leave space for speculative interpretations, the full complexity of the data reported in this work allows one to hypothesize mechanisms of action for the basis of inhibition. At least two mechanisms seem plausible, both involving lupin-γC-peculiar structures.
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Costa DAL, Filho EXF. Microbial β-mannosidases and their industrial applications. Appl Microbiol Biotechnol 2018; 103:535-547. [PMID: 30426153 DOI: 10.1007/s00253-018-9500-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 12/18/2022]
Abstract
Heteropolymers of mannan are polysaccharide components of the plant cell wall of gymnosperms and some angiosperms, including palm trees (Arecales and Monocot). Degradation of the complex structure of these polysaccharides requires the synergistic action of enzymes that disrupt the internal carbon skeleton of mannan and accessory enzymes that remove side chain substituents. However, complete degradation of these polysaccharides is carried out by an exo-hydrolase termed β-mannosidase. Microbial β-mannosidases belong to families 1, 2, and 5 of glycosyl hydrolases, and catalyze the hydrolysis of non-reducing ends of mannose oligomers. Besides, these enzymes are also involved in transglycosylation reactions. Because of their activity at different temperatures and pH values, these enzymes are used in a variety of industrial applications and the pharmaceutical, food, and biofuel industries.
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Pozzo T, Higdon SM, Pattathil S, Hahn MG, Bennett AB. Characterization of novel glycosyl hydrolases discovered by cell wall glycan directed monoclonal antibody screening and metagenome analysis of maize aerial root mucilage. PLoS One 2018; 13:e0204525. [PMID: 30256843 PMCID: PMC6157868 DOI: 10.1371/journal.pone.0204525] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/10/2018] [Indexed: 11/19/2022] Open
Abstract
An indigenous maize landrace from the Sierra Mixe region of Oaxaca, Mexico exhibits extensive formation of aerial roots which exude large volumes of a polysaccharide-rich gel matrix or "mucilage" that harbors diazotrophic microbiota. We hypothesize that the mucilage associated microbial community carries out multiple functions, including disassembly of the mucilage polysaccharide. In situ, hydrolytic assay of the mucilage revealed endogenous arabinofuranosidase, galactosidase, fucosidase, mannosidase and xylanase activities. Screening the mucilage against plant cell wall glycan-specific monoclonal antibodies recognized the presence of carbohydrate epitopes of hemicellulosic polysaccharides like xyloglucan (both non-fucosylated and fucosylated), xylan (both substituted and unsubstituted xylan domains) and pectic-arabinogalactans, all of which are potential carbon sources for mucilage microbial residents. Mucilage metagenome annotation using MG-RAST identified the members forming the microbial community, and gene fragments with predicted functions associated with carbohydrate disassembly. Data from the in situ hydrolytic activity and monoclonal antibody screening assays were used to guide the selection of five full length genes with predicted glycosyl hydrolase function from the GenBank database that were similar to gene fragments of high relative abundance in the mucilage metagenomes. These five genes were then synthesized for recombinant production in Escherichia coli. Here we report the characterization of an α-N-arabinofuranosidase (GH51) and an oligosaccharide reducing-end xylanase (GH8) from Flavobacterium johnsoniae; an α-L-fucosidase (GH29) and a xylan β-1,4 xylosidase (GH39) from Spirosoma linguale, and a β-mannosidase (GH2) from Agrobacterium fabrum. Biochemical characterization of these enzymes revealed a β-Mannosidase that also exhibits a secondary activity towards the cleavage of galactosyl residues. We also describe two xylanases (GH8 and GH39) from underexplored glycosyl hydrolase families, one thermostable α-L-Fucosidase (GH29) and a thermostable α-N-Arabinofuranosidase (GH51).
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Affiliation(s)
- Tania Pozzo
- Department of Plant Sciences, University of California, Davis, CA, United States of America
| | - Shawn M. Higdon
- Department of Plant Sciences, University of California, Davis, CA, United States of America
| | - Sivakumar Pattathil
- Mascoma LLC (Lallemand Inc.), Lebanon, NH, United States of America
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Michael G. Hahn
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States of America
| | - Alan B. Bennett
- Department of Plant Sciences, University of California, Davis, CA, United States of America
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Ladevèze S, Laville E, Despres J, Mosoni P, Potocki-Véronèse G. Mannoside recognition and degradation by bacteria. Biol Rev Camb Philos Soc 2016; 92:1969-1990. [PMID: 27995767 DOI: 10.1111/brv.12316] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/01/2016] [Accepted: 11/11/2016] [Indexed: 11/29/2022]
Abstract
Mannosides constitute a vast group of glycans widely distributed in nature. Produced by almost all organisms, these carbohydrates are involved in numerous cellular processes, such as cell structuration, protein maturation and signalling, mediation of protein-protein interactions and cell recognition. The ubiquitous presence of mannosides in the environment means they are a reliable source of carbon and energy for bacteria, which have developed complex strategies to harvest them. This review focuses on the various mannosides that can be found in nature and details their structure. It underlines their involvement in cellular interactions and finally describes the latest discoveries regarding the catalytic machinery and metabolic pathways that bacteria have developed to metabolize them.
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Affiliation(s)
- Simon Ladevèze
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077, Toulouse, France
| | - Elisabeth Laville
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077, Toulouse, France
| | - Jordane Despres
- INRA, UR454 Microbiologie, F-63122, Saint-Genès Champanelle, France
| | - Pascale Mosoni
- INRA, UR454 Microbiologie, F-63122, Saint-Genès Champanelle, France
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Affiliation(s)
- Prakram Singh Chauhan
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, SAS Nagar, Mohali, India and
| | - Naveen Gupta
- Department of Microbiology, Panjab University, Chandigarh, India
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Li YX, Liu Y, Yan QJ, Yang SQ, Jiang ZQ. Characterization of a novel glycoside hydrolase family 5 β-mannosidase from Absidia corymbifera with high transglycosylation activity. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.09.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Lin J, Zou Y, Ma C, She Q, Liang Y, Chen Z, Ge X. Heterologous Expression of Mannanase and Developing a New Reporter Gene System in Lactobacillus casei and Escherichia coli. PLoS One 2015; 10:e0142886. [PMID: 26562012 PMCID: PMC4643024 DOI: 10.1371/journal.pone.0142886] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 10/28/2015] [Indexed: 12/04/2022] Open
Abstract
Reporter gene systems are useful for studying bacterial molecular biology, including the regulation of gene expression and the histochemical analysis of protein products. Here, two genes, β-1,4-mannanase (manB) from Bacillus pumilus and β-glucuronidase (gusA) from Escherichia coli K12, were cloned into the expression vector pELX1. The expression patterns of these reporter genes in Lactobacillus casei were investigated by measuring their enzymatic activities and estimating their recombinant protein yields using western blot analysis. Whereas mannanase activity was positively correlated with the accumulation of ManB during growth, GusA activity was not; western blot analysis indicated that while the amount of GusA protein increased during later growth stages, GusA activity gradually decreased, indicating that the enzyme was inactive during cell growth. A similar trend was observed in E. coli JM109. We chose to use the more stable mannanase gene as the reporter to test secretion expression in L. casei. Two pELX1-based secretion vectors were constructed: one carried the signal peptide of the unknown secretion protein Usp45 from Lactococcus lactis (pELSH), and the other contained the full-length SlpA protein from the S-layer of L. acidophilus (pELWH). The secretion of ManB was detected in the supernatant of the pELSH-ManB transformants and in the S-layer of the cell surface of the pELWH-ManB transformants. This is the first report demonstrating that the B. pumilus manB gene is a useful reporter gene in L. casei and E.coli.
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Affiliation(s)
- Jinzhong Lin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Dairy Biotechnology, Technology Center of Bright Dairy & Food Co., Ltd., 1518 Jiangchang Road (W), Shanghai, 200436, China
| | - Yexia Zou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Chengjie Ma
- State Key Laboratory of Dairy Biotechnology, Technology Center of Bright Dairy & Food Co., Ltd., 1518 Jiangchang Road (W), Shanghai, 200436, China
| | - Qunxin She
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Department of Biology, University of Copenhagen, Biocenter, Ole Maaloes Vej 5, DK-2200, Copenhagen N, Denmark
| | - Yunxiang Liang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zhengjun Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- * E-mail: (ZC); (XG)
| | - Xiangyang Ge
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- * E-mail: (ZC); (XG)
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