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The Second-Generation Biomethane from Mandarin Orange Peel under Cocultivation with Methanogens and the Armed Clostridium cellulovorans. FERMENTATION-BASEL 2019. [DOI: 10.3390/fermentation5040095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study demonstrates that the consortium, which consists of the microbial flora of methane production (MFMP) and Clostridium cellulovorans grown with cellulose, can perform the direct conversion of cellulosic biomass to methane. The MFMP was taken from a commercial methane fermentation tank and was extremely complicated. Therefore, C. cellulovorans grown with cellobiose could not perform high degradation ability on cellulosic biomass due to competition by various microorganisms in MFMP. Focusing on the fact that C. cellulovorans was cultivated with cellulose, which is armed with cellulosome, so that it is now armed C. cellulovorans; the direct conversion was carried out by the consortium which consisted of MFMP and the armed C. cellulovorans. As a result, the consortium of C. cellulovorans grown with cellobiose and MFMP (CCeM) could not degrade the purified cellulose and mandarin orange peel. However, MFMP and the armed C. cellulovorans reduced 78.4% of the total sugar of the purified cellulose such as MN301, and produced 6.89 mL of methane simultaneously. Furthermore, the consortium consisted of MFMP and the armed C. cellulovorans degraded mandarin orange peel without any pretreatments and produced methane that was accounting for 66.2% of the total produced gas.
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Ferdinand PH, Borne R, Trotter V, Pagès S, Tardif C, Fierobe HP, Perret S. Are cellulosome scaffolding protein CipC and CBM3-containing protein HycP, involved in adherence of Clostridium cellulolyticum to cellulose? PLoS One 2013; 8:e69360. [PMID: 23935995 PMCID: PMC3723904 DOI: 10.1371/journal.pone.0069360] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/07/2013] [Indexed: 01/09/2023] Open
Abstract
Clostridium cellulolyticum, a mesophilic anaerobic bacterium, produces highly active enzymatic complexes called cellulosomes. This strain was already shown to bind to cellulose, however the molecular mechanism(s) involved is not known. In this context we focused on the gene named hycP, encoding a 250-kDa protein of unknown function, containing a Family-3 Carbohydrate Binding Module (CBM3) along with 23 hyaline repeat modules (HYR modules). In the microbial kingdom the gene hycP is only found in C. cellulolyticum and the very close strain recently sequenced Clostridium sp BNL1100. Its presence in C. cellulolyticum guided us to analyze its function and its putative role in adhesion of the cells to cellulose. The CBM3 of HycP was shown to bind to crystalline cellulose and was assigned to the CBM3b subfamily. No hydrolytic activity on cellulose was found with a mini-protein displaying representative domains of HycP. A C. cellulolyticum inactivated hycP mutant strain was constructed, and we found that HycP is neither involved in binding of the cells to cellulose nor that the protein has an obvious role in cell growth on cellulose. We also characterized the role of the cellulosome scaffolding protein CipC in adhesion of C. cellulolyticum to cellulose, since cellulosome scaffolding protein has been proposed to mediate binding of other cellulolytic bacteria to cellulose. A second mutant was constructed, where cipC was inactivated. We unexpectedly found that CipC is only partly involved in binding of C. cellulolyticum to cellulose. Other mechanisms for cellulose adhesion may therefore exist in C. cellulolyticum. In addition, no cellulosomal protuberances were observed at the cellular surface of C. cellulolyticum, what is in contrast to reports from several other cellulosomes producing strains. These findings may suggest that C. cellulolyticum has no dedicated molecular mechanism to aggregate the cellulosomes at the cellular surface.
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Tamaru Y, Miyake H, Kuroda K, Nakanishi A, Matsushima C, Doi RH, Ueda M. Comparison of the mesophilic cellulosome-producing Clostridium cellulovorans genome with other cellulosome-related clostridial genomes. Microb Biotechnol 2012; 4:64-73. [PMID: 21255373 PMCID: PMC3815796 DOI: 10.1111/j.1751-7915.2010.00210.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Clostridium cellulovorans, an anaerobic and mesophilic bacterium, degrades native substrates in soft biomass such as corn fibre and rice straw efficiently by producing an extracellular enzyme complex called the cellulosome. Recently, we have reported the whole‐genome sequence of C. cellulovorans comprising 4220 predicted genes in 5.10 Mbp [Y. Tamaru et al., (2010) J. Bacteriol., 192: 901–902]. As a result, the genome size of C. cellulovorans was about 1 Mbp larger than that of other cellulosome‐producing clostridia, mesophilic C. cellulolyticum and thermophilic C. thermocellum. A total of 57 cellulosomal genes were found in the C. cellulovorans genome, and they coded for not only carbohydrate‐degrading enzymes but also a lipase, peptidases and proteinase inhibitors. Interestingly, two novel genes encoding scaffolding proteins were found in the genome. According to KEGG metabolic pathways and their comparison with 11 Clostridial genomes, gene expansion in the C. cellulovorans genome indicated mainly non‐cellulosomal genes encoding hemicellulases and pectin‐degrading enzymes. Thus, by examining genome sequences from multiple Clostridium species, comparative genomics offers new insight into genome evolution and the way natural selection moulds functional DNA sequence evolution. Our analysis, coupled with the genome sequence data, provides a roadmap for constructing enhanced cellulosome‐producing Clostridium strains for industrial applications such as biofuel production.
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Affiliation(s)
- Yutaka Tamaru
- Department of Life Science, Mie University Graduate School of Bioresources, 1577 Kurimamachiya, Tsu, Mie 514-8507, Japan.
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Cellulase Production by Pink Pigmented Facultative Methylotrophic Strains (PPFMs). Appl Biochem Biotechnol 2011; 164:666-80. [DOI: 10.1007/s12010-011-9166-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
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Tamaru Y, Miyake H, Kuroda K, Ueda M, Doi RH. Comparative genomics of the mesophilic cellulosome-producing Clostridium cellulovorans and its application to biofuel production via consolidated bioprocessing. ENVIRONMENTAL TECHNOLOGY 2010; 31:889-903. [PMID: 20662379 DOI: 10.1080/09593330.2010.490856] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Clostridium cellulovorans is an anaerobic, mesophilic bacterium that efficiently degrades native substrates in soft biomass such as corn fibre and rice straw by producing an extracellular enzyme complex called the cellulosomes. By examining genome sequences from multiple Clostridium species, comparative genomics offers new insight into genome evolution and the way natural selection moulds functional DNA sequence evolution. Recently, we reported the whole genome sequence of C. cellulovorans. A total of 57 cellulosomal genes were found in the C. cellulovorans genome and coded for not only carbohydrate-active enzymes but also lipase, peptidase and proteinase inhibitors, in addition to two novel genes encoding scaffolding proteins CbpB and CbpC. Interestingly, the genome size of C. cellulovorans was about 1 Mbp larger than that of other cellulosome-producing clostridia: mesophilic C. cellulolyticum and thermophilic C. thermocellum. Since the C. cellulovorans genome included not only cellulosomal genes but also a large number of genes encoding non-cellulosomal enzymes, the genome expansion of C. cellulovorans included genes more related to degradation of polysaccharides, such as hemicelluloses and pectins, than to cellulose. In this review, we propose a strategy for industrial applications such as biofuel production using enhanced mesophilic cellulosome- and solvent-producing clostridia.
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Affiliation(s)
- Yutaka Tamaru
- Department of Life Science, Mie University Graduate School of Bioresourses, 1577 Kurimamachiya, Tsu, Mie 514-8507, Japan.
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Genome sequence of the cellulosome-producing mesophilic organism Clostridium cellulovorans 743B. J Bacteriol 2009; 192:901-2. [PMID: 19948806 DOI: 10.1128/jb.01450-09] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium cellulovorans 743B was isolated from a wood chip pile and is an anaerobic and mesophilic spore-forming bacterium. This organism degrades native substrates in soft biomass such as corn fiber and rice straw efficiently by producing an extracellular enzyme complex called the cellulosome. Here we report the genome sequence of C. cellulovorans 743B.
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Co-metabolic degradation of dimethoate by Raoultella sp. X1. Biodegradation 2008; 20:363-73. [DOI: 10.1007/s10532-008-9227-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022]
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Doi RH. Cellulases of mesophilic microorganisms: cellulosome and noncellulosome producers. Ann N Y Acad Sci 2007; 1125:267-79. [PMID: 18096849 DOI: 10.1196/annals.1419.002] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The cellulolytic activity of mesophilic bacteria and fungi is described, with special emphasis on the large extracellular enzyme complex called the cellulosome. The cellulosome is composed of a scaffolding protein, which is attached to various cellulolytic and hemicellulolytic enzymes, and this complex allows the organisms to degrade plant cell walls very efficently. The enzymes include a variety of cellulases, hemicellulases, and pectinases that work synergistically to degrade complex cell-wall molecules.
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Affiliation(s)
- Roy H Doi
- Section of Molecular and Cellular Biology, University of California, One Shields Avenue, Davis, CA 95616, USA.
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Desvaux M. Clostridium cellulolyticum: model organism of mesophilic cellulolytic clostridia. FEMS Microbiol Rev 2004; 29:741-64. [PMID: 16102601 DOI: 10.1016/j.femsre.2004.11.003] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 04/27/2004] [Accepted: 11/01/2004] [Indexed: 11/22/2022] Open
Abstract
Clostridium cellulolyticum ATCC 35319 is a non-ruminal mesophilic cellulolytic bacterium originally isolated from decayed grass. As with most truly cellulolytic clostridia, C. cellulolyticum possesses an extracellular multi-enzymatic complex, the cellulosome. The catalytic components of the cellulosome release soluble cello-oligosaccharides from cellulose providing the primary carbon substrates to support bacterial growth. As most cellulolytic bacteria, C. cellulolyticum was initially characterised by limited carbon consumption and subsequent limited growth in comparison to other saccharolytic clostridia. The first metabolic studies performed in batch cultures suggested nutrient(s) limitation and/or by-product(s) inhibition as the reasons for this limited growth. In most recent investigations using chemostat cultures, metabolic flux analysis suggests a self-intoxication of bacterial metabolism resulting from an inefficiently regulated carbon flow. The investigation of C. cellulolyticum physiology with cellobiose, as a model of soluble cellodextrin, and with pure cellulose, as a carbon source more closely related to lignocellulosic compounds, strengthen the idea of a bacterium particularly well adapted, and even restricted, to a cellulolytic lifestyle. The metabolic flux analysis from continuous cultures revealed that (i) in comparison to cellobiose, the cellulose hydrolysis by the cellulosome introduces an extra regulation of entering carbon flow resulting in globally lower metabolic fluxes on cellulose than on cellobiose, (ii) the glucose 1-phosphate/glucose 6-phosphate branch point controls the carbon flow directed towards glycolysis and dissipates carbon excess towards the formation of cellodextrins, glycogen and exopolysaccharides, (iii) the pyruvate/acetyl-CoA metabolic node is essential to the regulation of electronic and energetic fluxes. This in-depth analysis of C. cellulolyticum metabolism has permitted the first attempt to engineer metabolically a cellulolytic microorganism.
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Affiliation(s)
- Mickaël Desvaux
- Institute for Biomedical Research, The University of Birmingham - The Medical School, Edgbaston, UK.
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Ye Q, Roh Y, Carroll SL, Blair B, Zhou J, Zhang CL, Fields MW. Alkaline anaerobic respiration: isolation and characterization of a novel alkaliphilic and metal-reducing bacterium. Appl Environ Microbiol 2004; 70:5595-602. [PMID: 15345448 PMCID: PMC520920 DOI: 10.1128/aem.70.9.5595-5602.2004] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Iron-reducing enrichments were obtained from leachate ponds at the U.S. Borax Company in Boron, Calif. Based on partial small-subunit (SSU) rRNA gene sequences (approximately 500 nucleotides), six isolates shared 98.9% nucleotide identity. As a representative, the isolate QYMF was selected for further analysis. QYMF could be grown with Fe(III)-citrate, Fe(III)-EDTA, Co(III)-EDTA, or Cr(VI) as electron acceptors, and yeast extract and lactate could serve as electron donors. Growth during iron reduction occurred over the pH range of 7.5 to 11.0 (optimum, pH 9.5), a sodium chloride range of 0 to 80 g/liter (optimum, 20 g/liter), and a temperature range of 4 to 45 degrees C (optimum, approximately 35 degrees C), and iron precipitates were formed. QYMF was a strict anaerobe that could be grown in the presence of borax, and the cells were straight rods that produced endospores. Sodium chloride and yeast extract stimulated growth. Phylogenetic analysis of the SSU rRNA gene indicated that the bacterium was a low-G+C gram-positive microorganism and had 96 and 92% nucleotide identity with Alkaliphilus transvaalensis and Alkaliphilus crotonatoxidans, respectively. The major phospholipid fatty acids were 14:1, 16:1omega7c, and 16:0, which were different from those of other alkaliphiles but similar to those of reported iron-reducing bacteria. The results demonstrated that the isolate might represent a novel metal-reducing alkaliphilic species. The name Alkaliphilus metalliredigens sp. nov. is proposed. The isolation and activity of metal-reducing bacteria from borax-contaminated leachate ponds suggest that bioremediation of metal-contaminated alkaline environments may be feasible and have implications for alkaline anaerobic respiration.
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Affiliation(s)
- Qi Ye
- Department of Geology, University of Missouri, Columbia, MO, USA
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Krause DO, Denman SE, Mackie RI, Morrison M, Rae AL, Attwood GT, McSweeney CS. Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics. FEMS Microbiol Rev 2003; 27:663-93. [PMID: 14638418 DOI: 10.1016/s0168-6445(03)00072-x] [Citation(s) in RCA: 275] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The degradation of plant cell walls by ruminants is of major economic importance in the developed as well as developing world. Rumen fermentation is unique in that efficient plant cell wall degradation relies on the cooperation between microorganisms that produce fibrolytic enzymes and the host animal that provides an anaerobic fermentation chamber. Increasing the efficiency with which the rumen microbiota degrades fiber has been the subject of extensive research for at least the last 100 years. Fiber digestion in the rumen is not optimal, as is supported by the fact that fiber recovered from feces is fermentable. This view is confirmed by the knowledge that mechanical and chemical pretreatments improve fiber degradation, as well as more recent research, which has demonstrated increased fiber digestion by rumen microorganisms when plant lignin composition is modified by genetic manipulation. Rumen microbiologists have sought to improve fiber digestion by genetic and ecological manipulation of rumen fermentation. This has been difficult and a number of constraints have limited progress, including: (a) a lack of reliable transformation systems for major fibrolytic rumen bacteria, (b) a poor understanding of ecological factors that govern persistence of fibrolytic bacteria and fungi in the rumen, (c) a poor understanding of which glycolyl hydrolases need to be manipulated, and (d) a lack of knowledge of the functional genomic framework within which fiber degradation operates. In this review the major fibrolytic organisms are briefly discussed. A more extensive discussion of the enzymes involved in fiber degradation is included. We also discuss the use of plant genetic manipulation, application of free-living lignolytic fungi and the use of exogenous enzymes. Lastly, we will discuss how newer technologies such as genomic and metagenomic approaches can be used to improve our knowledge of the functional genomic framework of plant cell wall degradation in the rumen.
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Affiliation(s)
- Denis O Krause
- CSIRO Australia, Queensland Bioscience Precinct, St. Lucia, Qld 4067, Australia.
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Abstract
Cellulose comprises a major portion of biomass on the earth, and the turnover of this material contributes to the CO2 cycle. Cellulases, which play a major role in the turnover of cellulosic materials, have been found either as free enzymes that work synergistically, or as an enzyme complex called the cellulosome. This review summarizes some of the general properties of cellulosomes, and more specifically, the properties of the Clostridium cellulovorans cellulosome. The C cellulovorans cellulosome is an extracellular enzyme complex with a molecular weight of about 1 x 10(6), and is comprised of at least ten subunits. The major subunit is the scaffolding protein CbpA, with a molecular weight of 189,000. This nonenzymatic subunit contains a cellulose binding domain (CBD) that binds the cellulosome to the substrate, nine conserved cohesins or enzyme binding domains, and four conserved surface layer homologous (SLH) domains. It is postulated that the SLH domains help to bind the cellulosome to the cell surface. The cellulosomal enzymes include cellulases (family 5 and 9 endoglucanases and a family 48 exoglucanase), a mannanase, a xylanase, and a pectate lyase. The cellulosome is capable of converting Arabidopsis and tobacco plant cells to protoplasts. One of the endoglucanases, EngE, contains three tandemly repeated SLHs at its N-terminus, and therefore appears capable of binding to the scaffolding protein CbpA as well as to the cell surface. Cellulosomes can attack crystalline cellulose, but the free cellulosomal enzymes can attack only soluble and amorphous celluloses. Nine genes for the cellulosome are found in a gene cluster cbpA-exgS-engH-engK-hbpA-engL-manA-engM-engN. Other cellulosomal genes such as engB, engE, and engY are not linked to the major gene cluster or to each other. By determining the structure and function of the cellulosome, we hope to increase the efficiency of the cellulosome by genetic engineering techniques.
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Affiliation(s)
- R H Doi
- Section of Molecular & Cellular Biology, Division of Biological Sciences, University of California, Davis 95616, USA.
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Abstract
We divided the adhesion process of the predominant cellulolytic rumen bacteria Fibrobacter succinogenes, Ruminococcus flavefaciens, and Ruminococcus albus into four phases: 1) transport of the nonmotile bacteria to the substrate; 2) initial nonspecific adhesion of bacteria to unprotected sites of the substrate that is dominated by constitutive elements of bacterial glycocalyx; 3) specific adhesion via adhesins or ligands formation with the substrate, which can be dominated by several bacterial organelles including cellulosome complexes, fimbriae connections, glycosylated epitopes of cellulose-binding protein (CBP) or glycocalyx, and cellulose-binding domain (CBD) of enzymes; 4) proliferation of the attached bacteria on potentially digestible tissues of the substrate. Each of the phases and its significance in the adhesion process are described. Factors affecting bacterial adhesion are described including: 1) factors related to bacterial age, glycocalyx condition, and microbial competition; 2) factors related to the nature of substrate including, cuticle protection, surface area, hydration, and ionic charge; and 3) environmental factors including pH, temperature, and presence of cations and soluble carbohydrate. Based on the information available from the literature, it appears that each of the predominant rumen bacteria--F. succinogenes, R. flavefaciens, and R. albus--has a specific mechanism of adhesion to cellulose. In F. succinogenes, both the glycosidic residues of the outer membrane CBP and especially of the 180-kDa CBP, and the distinct CBD of EG2 EGF and Cl-stimulated cellobiosidase, may play a role in the adhesion to cellulose. No direct evidence, except scanning electron microscopy observations, yet supports the existence of either cellulosome complex or fimbriae structures involved in the adhesion mechanism of F. succinogenes. At least two mechanisms, cellulosome-like complexes and carbohydrate epitopes of the glycocalyx layer are involved in the specific adhesion of R. flavefaciens to cellulose. Ruminococcus albus possesses at least two mechanisms for specific adhesion to cellulose: a cellulosomal-like mechanism, and a CbpC (Pil)-protein mechanism that probably involves the production of fimbrial-like structures. Indirect and direct studies suggested that carbohydrate epitopes of CBPs and CBD epitope of cellulases may also be involved mostly in the nonspecific phase of adhesion of R. albus.
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Affiliation(s)
- J Miron
- Metabolic Unit, Agricultural Research Organization, The Volcani Center, Bet-Dagan, Israel.
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Cellulose-inducible Ultrastructural Protuberances and Cellulose-affinity Proteins of Eubacterium cellulosolvens. Anaerobe 1999. [DOI: 10.1006/anae.1999.0302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Blair BG, Anderson KL. Regulation of cellulose-inducible structures of Clostridium cellulovorans. Can J Microbiol 1999; 45:242-9. [PMID: 10408097 DOI: 10.1139/w99-004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Scanning electron microscopy was used to detect ultrastructural protuberances on the cellulolytic anaerobe Clostridium cellulovorans. Numerous ultrastructural protuberances were observed on cellulose-grown cells, but few were detected on glucose-, fructose-, cellobiose-, or carboxymethylcellulose (CMC)-grown cells. Formation of these protuberances was detected within 2 h of incubation in cellulose medium, but 4 h incubation was required before numerous structures were observed on the cells. When a soluble carbohydrate or CMC was mixed with cellulose-grown cells, the ultrastructural protuberances could no longer be detected. In fact, no protuberances were observed within 5 min following the addition of glucose, cellobiose, or methylglucose to cellulose-grown cells. The presence of these protuberances corresponded with the binding of the Bandeiraea simplicifolia BSI-B4 isolectin to the cell. Cellulose-grown cells had a greater level of observable lectin binding than cellobiose-grown cells, and lectin binding was not detected on glucose- or fructose-grown cells. In addition, lectin binding ability was lost by cellulose-grown cells following the addition of glucose, fructose, or methylglucose to the cellulose medium. A cellulose-affinity protein fraction expressing cellulase activity was also detected in cell extracts of cellobiose- or cellulose-grown cultures. However, this protein fraction was not detected in extracts of glucose-grown cultures, and was rapidly lost (within 5 min) following the addition of glucose to cellulose-grown cultures. The ability of C. cellulovorans to adhere to cellulose was also affected by the energy substrate, but not in the same manner as the protuberance formation or the cellulase-containing protein fraction. Rather, cellobiose-, cellulose-, and CMC-grown cultures adhered to cellulose, but this adherence was not affected by addition of glucose to the medium. This is the first report that soluble carbohydrates caused the rapid loss of some cellulose-inducible systems of C. cellulovorans.
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Affiliation(s)
- B G Blair
- Department of Biological Sciences, Mississippi State University 39762, USA
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Pagès S, Bélaïch A, Fierobe HP, Tardif C, Gaudin C, Bélaïch JP. Sequence analysis of scaffolding protein CipC and ORFXp, a new cohesin-containing protein in Clostridium cellulolyticum: comparison of various cohesin domains and subcellular localization of ORFXp. J Bacteriol 1999; 181:1801-10. [PMID: 10074072 PMCID: PMC93578 DOI: 10.1128/jb.181.6.1801-1810.1999] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene encoding the scaffolding protein of the cellulosome from Clostridium cellulolyticum, whose partial sequence was published earlier (S. Pagès, A. Bélaïch, C. Tardif, C. Reverbel-Leroy, C. Gaudin, and J.-P. Bélaïch, J. Bacteriol. 178:2279-2286, 1996; C. Reverbel-Leroy, A. Bélaïch, A. Bernadac, C. Gaudin, J. P. Bélaïch, and C. Tardif, Microbiology 142:1013-1023, 1996), was completely sequenced. The corresponding protein, CipC, is composed of a cellulose binding domain at the N terminus followed by one hydrophilic domain (HD1), seven highly homologous cohesin domains (cohesin domains 1 to 7), a second hydrophilic domain, and a final cohesin domain (cohesin domain 8) which is only 57 to 60% identical to the seven other cohesin domains. In addition, a second gene located 8.89 kb downstream of cipC was found to encode a three-domain protein, called ORFXp, which includes a cohesin domain. By using antiserum raised against the latter, it was observed that ORFXp is associated with the membrane of C. cellulolyticum and is not detected in the cellulosome fraction. Western blot and BIAcore experiments indicate that cohesin domains 1 and 8 from CipC recognize the same dockerins and have similar affinity for CelA (Ka = 4.8 x 10(9) M-1) whereas the cohesin from ORFXp, although it is also able to bind all cellulosome components containing a dockerin, has a 19-fold lower Ka for CelA (2.6 x 10(8) M-1). Taken together, these data suggest that ORFXp may play a role in cellulosome assembly.
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Affiliation(s)
- S Pagès
- Bioénergétique et Ingéniérie des Protéines, Centre National de la Recherche Scientifique, Marseilles, France
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Anderson KL. Cationized ferritin as a stain for electron microscopic observation of bacterial ultrastructure. Biotech Histochem 1998; 73:278-88. [PMID: 9829420 DOI: 10.3109/10520299809141121] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The electron microscope has proven very effective for visualization of various morphological features of bacteria. Cationized ferritin (CF) is a stain commonly used to increase the electron microscopic resolution of bacterial cells, thereby enabling detailed analysis of their morphological and structural features. CF has been useful for microscopic examination of the bacterial capsule, cell wall, S-layer, and various unique morphological structures. In addition, as a cation, CF binds only to negatively charged molecules. Thus, CF has been used to identify sites of anionic charge on the bacterial cell surface, which has led to insights concerning the formation and turnover of bacterial peptidoglycan and the S-layer proteins. As a cation, however, CF may also interact with certain cellular components, causing erroneous interpretation of microscopic results. This review provides a discussion of both the strengths and weaknesses of CF when used as a stain for electron microscopy.
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Affiliation(s)
- K L Anderson
- Department of Biological Sciences, Mississippi State University, Mississippi State 39762, USA.
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