The Experts below are selected from a list of 9756 Experts worldwide ranked by ideXlab platform
D.m. Broda - One of the best experts on this subject based on the ideXlab platform.
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sources of psychrophilic and psychrotolerant Clostridia causing spoilage of vacuum packed chilled meats as determined by pcr amplification procedure
Journal of Applied Microbiology, 2009Co-Authors: D.m. Broda, J.a. Boerema, Gale BrightwellAbstract:Aims: To determine possible preslaughter and processing sources of psychrophilic and psychrotolerant Clostridia causing spoilage of vacuum-packed chilled meats. Methods and Results: Molecular methods based on the polymerase chain reaction (PCR) amplification of specific 16S rDNA fragments were used to detect the presence of Clostridium gasigenes, Clostridium estertheticum, Clostridium algidicarnis and Clostridium putrefaciens in a total of 357 samples collected from ten slaughter stock supply farms, slaughter stock, two lamb-processing plants, their environments, dressed carcasses and final vacuum-packed meat stored at –0·5°C for 5½ weeks. Clostridium gasigenes, C. estertheticum and C. algidicarnis/C. putrefaciens were commonly detected in farm, faeces, fleece and processing environmental samples collected at the slaughter floor operations prior to fleece removal, but all these micro-organisms were detected in only 4 out of 26 cooling floor and chiller environmental samples. One out of 42 boning room environmental samples tested positive for the presence of C. gasigenes and C. estertheticum, but 25 out of 42 of these samples were positive for C. algidicarnis/C. putrefaciens. Nearly all of the 31 faecal samples tested positive for the presence of C. gasigenes and C. estertheticum; however, only two of these samples were positive for C. algidicarnis and/or C. putrefaciens. Clostridial species that were subject to this investigation were frequently detected on chilled dressed carcasses. Conclusions: The major qualitative and quantitative differences between the results of PCR detection obtained with the primers specific for ‘blown pack’ -causing Clostridia (C. gasigenes and C. estertheticum) and those obtained with primers specific for C. algidicarnis and C. putrefaciens suggest that the control of meat spoilage caused by different groups of meat Clostridia is best approached individually for each group. Significance and Impact of the Study: This paper provides information significant for controlling meat spoilage-causing Clostridia in the meat-processing plants.
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pcr detection of psychrophilic clostridium spp causing blown pack spoilage of vacuum packed chilled meats
Journal of Applied Microbiology, 2003Co-Authors: D.m. Broda, J.a. Boerema, R.g. BellAbstract:Aims: To develop a practical molecular procedure that directly, without isolation, and specifically detects the presence of Clostridia which cause ‘blown pack’ spoilage of vacuum-packed meat. Methods and Results: Primer sets and PCR amplification procedures were developed that detect the presence of 16S rDNA gene and/or 16S-23S rDNA internal transcribed spacer fragments of ‘blown pack’ causing Clostridia in meat. The specificity of the developed procedures was evaluated with DNA obtained from close phylogenetic neighbours of ‘blown pack’ causing Clostridia, food Clostridia and common meat spoilage microorganisms. The sensitivity of detection was assessed in non-enriched and low-temperature-enriched beef mince inoculated with serially diluted pure cultures of Clostridium estertheticum DSMZ 8809T and Cl. gasigenes DB1AT . The efficacy of detection procedures was evaluated for naturally contaminated vacuum-packed meat samples. Three primer sets, 16SE, 16SDB and EISR, produced amplicons of the expected size with DNA templates from target Clostridia, but failed to yield PCR products with DNAs from any other microorganisms tested. With 16SE and 16SDB primers, minimum levels of detection were 104 CFU g−1 for non-enriched, and 102 CFU g−1 for enriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, Cl. gasigenes was confirmed as the causative agent of ‘blown pack’ spoilage in two packs, and Cl. estertheticum as the causative agent in the third. Conclusions: The developed method can be used for rapid detection of ‘blown pack’ causing Clostridia in commercial blown packs, or following low temperature enrichment, for detection of these microorganisms in meat containing as few as 100 Clostridial cells per gram. Significance and Impact of the Study: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of Clostridial ‘blown pack’ spoilage in commercial spoiled packs, or for detection of psychrophilic Clostridia in epidemiological trace back of ‘blown pack’ spoilage incidents in meat processing plants.
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the abattoir source of culturable psychrophilic clostridium spp causing blown pack spoilage of vacuum packed chilled venison
Journal of Applied Microbiology, 2002Co-Authors: D.m. Broda, J.a. Boerema, R.g. Bell, D R MusgraveAbstract:Aims: To identify the abattoir source(s) of culturable psychrophilic Clostridia causing ‘blown pack’ spoilage of vacuum-packed chilled meats. Methods and Results: Psychrophilic and psychrotolerant Clostridia were isolated from hides, faeces and tonsils of deer slaughter stock, and from a meat plant environment. The isolates were differentiated using restriction fragment length polymorphism analysis of the 16S rDNA gene (PCR–RFLP) and 16S-23S rDNA internal transcribed spacer (ITS) analysis. PCR–RFLP group I Clostridia were found to have restriction patterns indistinguishable from the patterns of ‘blown pack’-causing Clostridium gasigenes DB1AT and R26. Gas production in packs inoculated with vegetative cells of PCR–RFLP group I Clostridia was first evident after 14 days at 2 °C. The prevalence of these Clostridia was similar in hide and faecal samples from slaughter animals, but these micro-organisms were absent from tonsils and the meat plant environment. Banding patterns of PCR–RFLP group II Clostridia showed some cross-similarity with patterns of the ‘blown pack’-causing micro-organism Cl. estertheticum DSM 8809T and Cl. estertheticum-like meat strains. The majority of Clostridia in PCR–RFLP group II were found in the faeces of slaughter animals. Isolates representing PCR–RFLP group II did not, however, produce gas in vacuum packs stored at 2 °C for 84 days. Conclusions: The data suggest that soil particles attached to hide or present in faeces are the most probable primary reservoir from which ‘blown pack’ Clostridia are introduced onto carcasses. Therefore, dressing procedure hygiene remains paramount in order to control the spread of psychrophilic Clostridium spp. in a meat plant. Significance and Impact of the Study: The paper provides information critical for controlling ‘blown pack’ spoilage in meat processing plants. It reports on the use of molecular techniques for determination of abattoir sources of ‘blown pack’-causing Clostridia.
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PCR detection of psychrotolerant Clostridia associated with deep tissue spoilage of vacuum-packed chilled meats.
Letters in applied microbiology, 2002Co-Authors: J.a. Boerema, D.m. Broda, R.g. BellAbstract:Aims: To develop a practical molecular procedure that directly (without isolation) and specifically detects the presence of Clostridia, which cause the deep tissue spoilage condition . Methods and Results: A primer set was designed and a PCR amplification procedure developed to detect the presence of Clostridium algidicarnis and Cl. putrefaciens 16S rDNA gene fragments in meat. The procedure yielded amplicons of the expected size with homologous DNA templates, but failed to give PCR products with DNAs from 47 food Clostridia and common meat spoilage micro-organisms. The minimum level of detection was 104 cfu g−1 for nonenriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, the presence of Cl. algidicarnis and/or Cl. putrefaciens was confirmed in a swab sample taken from the cartilage of an ovine stifle joint, which on opening exhibited strong offensive odours. Conclusions: The developed method can be used for rapid detection of Clostridia causing deep tissue spoilage in commercial vacuum packs. Significance and Impact of the Study: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of deep tissue Clostridial spoilage in commercial vacuum-packed chilled meats.
R.g. Bell - One of the best experts on this subject based on the ideXlab platform.
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molecular differentiation of Clostridia associated with blown pack spoilage of vacuum packed meats using internal transcribed spacer polymorphism analysis
International Journal of Food Microbiology, 2003Co-Authors: Dorota M Broda, D R Musgrave, R.g. BellAbstract:Abstract The 16S–23S rDNA internal transcribed spacer (ITS) polymorphism analysis was assessed for its suitability in rapid discrimination between species of psychrophilic and psychrotolerant Clostridia associated with ‘blown pack’ spoilage of vacuum-packed meats. DNA isolated from 10 reference and 20 meat strains of psychrophilic and psychrotolerant Clostridia were used as templates in PCR amplification with primers complementary to conserved regions of the 3′ end of the 16S rRNA and 5′ end of the 23S rRNA genes directly flanking the spacer. The majority of strains showed multi-band ITS patterns when products of spacer amplification were visualised on an agarose gel. With the majority of meat strains, PCR amplification generated single banding pattern for a single Clostridial species. However, meat strains of Cl. algidicarnis produced four different ITS banding patterns. With reference strains of psychrophilic and psychrotolerant Clostridia, variation in spacer length was also observed between nonproteolytic Cl. botulinum type B (17B), E (Beluga) and F (202F). On the other hand, the number and size of the ITS amplification products could not be used for a differentiation of Cl. laramiense ATCC 51254T from Cl. estertheticum DSM 8809T, Cl. putrefaciens DSM 1291T from Cl. algidicarnis NCFB 2931T, or Cl. frigidicarnis strains from nonproteolytic Cl. botulinum type B (17B). The presence of interstrain, and lack of interspecies, ITS polymorphism observed in the present study with some Clostridial species may preclude the use of 16S–23S rDNA spacer amplification for species-level discrimination and identification, respectively, of psychrophilic and psychrotolerant Clostridia associated with meat spoilage. However, where interstrain, intraspecies heterogeneity of ITS amplification products exists, ITS analysis could be useful for tracing back psychrophilic and psychrotolerant Clostridia responsible for meat spoilage to their meat plant sources.
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pcr detection of psychrophilic clostridium spp causing blown pack spoilage of vacuum packed chilled meats
Journal of Applied Microbiology, 2003Co-Authors: D.m. Broda, J.a. Boerema, R.g. BellAbstract:Aims: To develop a practical molecular procedure that directly, without isolation, and specifically detects the presence of Clostridia which cause ‘blown pack’ spoilage of vacuum-packed meat. Methods and Results: Primer sets and PCR amplification procedures were developed that detect the presence of 16S rDNA gene and/or 16S-23S rDNA internal transcribed spacer fragments of ‘blown pack’ causing Clostridia in meat. The specificity of the developed procedures was evaluated with DNA obtained from close phylogenetic neighbours of ‘blown pack’ causing Clostridia, food Clostridia and common meat spoilage microorganisms. The sensitivity of detection was assessed in non-enriched and low-temperature-enriched beef mince inoculated with serially diluted pure cultures of Clostridium estertheticum DSMZ 8809T and Cl. gasigenes DB1AT . The efficacy of detection procedures was evaluated for naturally contaminated vacuum-packed meat samples. Three primer sets, 16SE, 16SDB and EISR, produced amplicons of the expected size with DNA templates from target Clostridia, but failed to yield PCR products with DNAs from any other microorganisms tested. With 16SE and 16SDB primers, minimum levels of detection were 104 CFU g−1 for non-enriched, and 102 CFU g−1 for enriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, Cl. gasigenes was confirmed as the causative agent of ‘blown pack’ spoilage in two packs, and Cl. estertheticum as the causative agent in the third. Conclusions: The developed method can be used for rapid detection of ‘blown pack’ causing Clostridia in commercial blown packs, or following low temperature enrichment, for detection of these microorganisms in meat containing as few as 100 Clostridial cells per gram. Significance and Impact of the Study: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of Clostridial ‘blown pack’ spoilage in commercial spoiled packs, or for detection of psychrophilic Clostridia in epidemiological trace back of ‘blown pack’ spoilage incidents in meat processing plants.
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the abattoir source of culturable psychrophilic clostridium spp causing blown pack spoilage of vacuum packed chilled venison
Journal of Applied Microbiology, 2002Co-Authors: D.m. Broda, J.a. Boerema, R.g. Bell, D R MusgraveAbstract:Aims: To identify the abattoir source(s) of culturable psychrophilic Clostridia causing ‘blown pack’ spoilage of vacuum-packed chilled meats. Methods and Results: Psychrophilic and psychrotolerant Clostridia were isolated from hides, faeces and tonsils of deer slaughter stock, and from a meat plant environment. The isolates were differentiated using restriction fragment length polymorphism analysis of the 16S rDNA gene (PCR–RFLP) and 16S-23S rDNA internal transcribed spacer (ITS) analysis. PCR–RFLP group I Clostridia were found to have restriction patterns indistinguishable from the patterns of ‘blown pack’-causing Clostridium gasigenes DB1AT and R26. Gas production in packs inoculated with vegetative cells of PCR–RFLP group I Clostridia was first evident after 14 days at 2 °C. The prevalence of these Clostridia was similar in hide and faecal samples from slaughter animals, but these micro-organisms were absent from tonsils and the meat plant environment. Banding patterns of PCR–RFLP group II Clostridia showed some cross-similarity with patterns of the ‘blown pack’-causing micro-organism Cl. estertheticum DSM 8809T and Cl. estertheticum-like meat strains. The majority of Clostridia in PCR–RFLP group II were found in the faeces of slaughter animals. Isolates representing PCR–RFLP group II did not, however, produce gas in vacuum packs stored at 2 °C for 84 days. Conclusions: The data suggest that soil particles attached to hide or present in faeces are the most probable primary reservoir from which ‘blown pack’ Clostridia are introduced onto carcasses. Therefore, dressing procedure hygiene remains paramount in order to control the spread of psychrophilic Clostridium spp. in a meat plant. Significance and Impact of the Study: The paper provides information critical for controlling ‘blown pack’ spoilage in meat processing plants. It reports on the use of molecular techniques for determination of abattoir sources of ‘blown pack’-causing Clostridia.
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PCR detection of psychrotolerant Clostridia associated with deep tissue spoilage of vacuum-packed chilled meats.
Letters in applied microbiology, 2002Co-Authors: J.a. Boerema, D.m. Broda, R.g. BellAbstract:Aims: To develop a practical molecular procedure that directly (without isolation) and specifically detects the presence of Clostridia, which cause the deep tissue spoilage condition . Methods and Results: A primer set was designed and a PCR amplification procedure developed to detect the presence of Clostridium algidicarnis and Cl. putrefaciens 16S rDNA gene fragments in meat. The procedure yielded amplicons of the expected size with homologous DNA templates, but failed to give PCR products with DNAs from 47 food Clostridia and common meat spoilage micro-organisms. The minimum level of detection was 104 cfu g−1 for nonenriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, the presence of Cl. algidicarnis and/or Cl. putrefaciens was confirmed in a swab sample taken from the cartilage of an ovine stifle joint, which on opening exhibited strong offensive odours. Conclusions: The developed method can be used for rapid detection of Clostridia causing deep tissue spoilage in commercial vacuum packs. Significance and Impact of the Study: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of deep tissue Clostridial spoilage in commercial vacuum-packed chilled meats.
J.a. Boerema - One of the best experts on this subject based on the ideXlab platform.
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sources of psychrophilic and psychrotolerant Clostridia causing spoilage of vacuum packed chilled meats as determined by pcr amplification procedure
Journal of Applied Microbiology, 2009Co-Authors: D.m. Broda, J.a. Boerema, Gale BrightwellAbstract:Aims: To determine possible preslaughter and processing sources of psychrophilic and psychrotolerant Clostridia causing spoilage of vacuum-packed chilled meats. Methods and Results: Molecular methods based on the polymerase chain reaction (PCR) amplification of specific 16S rDNA fragments were used to detect the presence of Clostridium gasigenes, Clostridium estertheticum, Clostridium algidicarnis and Clostridium putrefaciens in a total of 357 samples collected from ten slaughter stock supply farms, slaughter stock, two lamb-processing plants, their environments, dressed carcasses and final vacuum-packed meat stored at –0·5°C for 5½ weeks. Clostridium gasigenes, C. estertheticum and C. algidicarnis/C. putrefaciens were commonly detected in farm, faeces, fleece and processing environmental samples collected at the slaughter floor operations prior to fleece removal, but all these micro-organisms were detected in only 4 out of 26 cooling floor and chiller environmental samples. One out of 42 boning room environmental samples tested positive for the presence of C. gasigenes and C. estertheticum, but 25 out of 42 of these samples were positive for C. algidicarnis/C. putrefaciens. Nearly all of the 31 faecal samples tested positive for the presence of C. gasigenes and C. estertheticum; however, only two of these samples were positive for C. algidicarnis and/or C. putrefaciens. Clostridial species that were subject to this investigation were frequently detected on chilled dressed carcasses. Conclusions: The major qualitative and quantitative differences between the results of PCR detection obtained with the primers specific for ‘blown pack’ -causing Clostridia (C. gasigenes and C. estertheticum) and those obtained with primers specific for C. algidicarnis and C. putrefaciens suggest that the control of meat spoilage caused by different groups of meat Clostridia is best approached individually for each group. Significance and Impact of the Study: This paper provides information significant for controlling meat spoilage-causing Clostridia in the meat-processing plants.
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pcr detection of psychrophilic clostridium spp causing blown pack spoilage of vacuum packed chilled meats
Journal of Applied Microbiology, 2003Co-Authors: D.m. Broda, J.a. Boerema, R.g. BellAbstract:Aims: To develop a practical molecular procedure that directly, without isolation, and specifically detects the presence of Clostridia which cause ‘blown pack’ spoilage of vacuum-packed meat. Methods and Results: Primer sets and PCR amplification procedures were developed that detect the presence of 16S rDNA gene and/or 16S-23S rDNA internal transcribed spacer fragments of ‘blown pack’ causing Clostridia in meat. The specificity of the developed procedures was evaluated with DNA obtained from close phylogenetic neighbours of ‘blown pack’ causing Clostridia, food Clostridia and common meat spoilage microorganisms. The sensitivity of detection was assessed in non-enriched and low-temperature-enriched beef mince inoculated with serially diluted pure cultures of Clostridium estertheticum DSMZ 8809T and Cl. gasigenes DB1AT . The efficacy of detection procedures was evaluated for naturally contaminated vacuum-packed meat samples. Three primer sets, 16SE, 16SDB and EISR, produced amplicons of the expected size with DNA templates from target Clostridia, but failed to yield PCR products with DNAs from any other microorganisms tested. With 16SE and 16SDB primers, minimum levels of detection were 104 CFU g−1 for non-enriched, and 102 CFU g−1 for enriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, Cl. gasigenes was confirmed as the causative agent of ‘blown pack’ spoilage in two packs, and Cl. estertheticum as the causative agent in the third. Conclusions: The developed method can be used for rapid detection of ‘blown pack’ causing Clostridia in commercial blown packs, or following low temperature enrichment, for detection of these microorganisms in meat containing as few as 100 Clostridial cells per gram. Significance and Impact of the Study: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of Clostridial ‘blown pack’ spoilage in commercial spoiled packs, or for detection of psychrophilic Clostridia in epidemiological trace back of ‘blown pack’ spoilage incidents in meat processing plants.
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the abattoir source of culturable psychrophilic clostridium spp causing blown pack spoilage of vacuum packed chilled venison
Journal of Applied Microbiology, 2002Co-Authors: D.m. Broda, J.a. Boerema, R.g. Bell, D R MusgraveAbstract:Aims: To identify the abattoir source(s) of culturable psychrophilic Clostridia causing ‘blown pack’ spoilage of vacuum-packed chilled meats. Methods and Results: Psychrophilic and psychrotolerant Clostridia were isolated from hides, faeces and tonsils of deer slaughter stock, and from a meat plant environment. The isolates were differentiated using restriction fragment length polymorphism analysis of the 16S rDNA gene (PCR–RFLP) and 16S-23S rDNA internal transcribed spacer (ITS) analysis. PCR–RFLP group I Clostridia were found to have restriction patterns indistinguishable from the patterns of ‘blown pack’-causing Clostridium gasigenes DB1AT and R26. Gas production in packs inoculated with vegetative cells of PCR–RFLP group I Clostridia was first evident after 14 days at 2 °C. The prevalence of these Clostridia was similar in hide and faecal samples from slaughter animals, but these micro-organisms were absent from tonsils and the meat plant environment. Banding patterns of PCR–RFLP group II Clostridia showed some cross-similarity with patterns of the ‘blown pack’-causing micro-organism Cl. estertheticum DSM 8809T and Cl. estertheticum-like meat strains. The majority of Clostridia in PCR–RFLP group II were found in the faeces of slaughter animals. Isolates representing PCR–RFLP group II did not, however, produce gas in vacuum packs stored at 2 °C for 84 days. Conclusions: The data suggest that soil particles attached to hide or present in faeces are the most probable primary reservoir from which ‘blown pack’ Clostridia are introduced onto carcasses. Therefore, dressing procedure hygiene remains paramount in order to control the spread of psychrophilic Clostridium spp. in a meat plant. Significance and Impact of the Study: The paper provides information critical for controlling ‘blown pack’ spoilage in meat processing plants. It reports on the use of molecular techniques for determination of abattoir sources of ‘blown pack’-causing Clostridia.
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PCR detection of psychrotolerant Clostridia associated with deep tissue spoilage of vacuum-packed chilled meats.
Letters in applied microbiology, 2002Co-Authors: J.a. Boerema, D.m. Broda, R.g. BellAbstract:Aims: To develop a practical molecular procedure that directly (without isolation) and specifically detects the presence of Clostridia, which cause the deep tissue spoilage condition . Methods and Results: A primer set was designed and a PCR amplification procedure developed to detect the presence of Clostridium algidicarnis and Cl. putrefaciens 16S rDNA gene fragments in meat. The procedure yielded amplicons of the expected size with homologous DNA templates, but failed to give PCR products with DNAs from 47 food Clostridia and common meat spoilage micro-organisms. The minimum level of detection was 104 cfu g−1 for nonenriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, the presence of Cl. algidicarnis and/or Cl. putrefaciens was confirmed in a swab sample taken from the cartilage of an ovine stifle joint, which on opening exhibited strong offensive odours. Conclusions: The developed method can be used for rapid detection of Clostridia causing deep tissue spoilage in commercial vacuum packs. Significance and Impact of the Study: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of deep tissue Clostridial spoilage in commercial vacuum-packed chilled meats.
Weihong Jiang - One of the best experts on this subject based on the ideXlab platform.
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the small rna sr8384 is a crucial regulator of cell growth in solventogenic Clostridia
Applied and Environmental Microbiology, 2020Co-Authors: Yunpeng Yang, Nannan Lang, Huan Zhang, Lu Zhang, Changsheng Chai, Weihong JiangAbstract:Small RNAs (sRNAs) are crucial regulatory molecules in organisms and are well-known not only for their roles in the control of diverse crucial biological processes but also for their value in regulation rewiring. However, to date, in Gram-positive anaerobic solventogenic Clostridia (a group of important industrial bacteria with exceptional substrate and product diversity), sRNAs remain minimally explored, and thus there is a lack of detailed understanding regarding these important molecules and their use as targets for genetic improvement. Here, we performed large-scale phenotypic screens of a transposon-mediated mutant library of Clostridium acetobutylicum, a typical solventogenic Clostridial species, and discovered a novel sRNA (sr8384) that functions as a crucial regulator of cell growth. Comparative transcriptomic data combined with genetic and biochemical analyses revealed that sr8384 acts as a pleiotropic regulator and controls multiple targets that are associated with crucial biological processes through direct or indirect interactions. Notably, the in vivo expression level of sr8384 determined the cell growth rate, thereby affecting the solvent titer and productivity. These findings indicate the importance of the sr8384-mediated regulatory network in C. acetobutylicum Furthermore, a homolog of sr8384 was discovered and proven to be functional in another important Clostridium species, C. beijerinckii, suggesting the potential broad role of this sRNA in Clostridia. Our work showcases a previously unknown potent and complex role of sRNAs in Clostridia, providing new opportunities for understanding and engineering these anaerobes.IMPORTANCE The uses of sRNAs as new resources for functional studies and strain modifications are promising strategies in microorganisms. However, these crucial regulatory molecules have hardly been explored in industrially important solventogenic Clostridia. Here, we identified sr8384 as a novel determinant sRNA controlling the cell growth of solventogenic Clostridium acetobutylicum Based on a detailed functional analysis, we further reveal the pleiotropic function of sr8384 and its multiple direct and indirect crucial targets, which represents a valuable source for understanding and optimizing this anaerobe. Of note, manipulation of this sRNA achieves improved cell growth and solvent synthesis. Our findings provide a new perspective for future studies on regulatory sRNAs in Clostridia.
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a novel regulatory pathway consisting of a two component system and an abc type transporter contributes to butanol tolerance in clostridium acetobutylicum
Applied Microbiology and Biotechnology, 2020Co-Authors: Yunpeng Yang, Nannan Lang, L Zhang, Weihong JiangAbstract:Despite the long-term interest in solventogenic Clostridia-based ABE (acetone-butanol-ethanol) fermentation, Clostridial butanol tolerance and its underlying mechanism remain poorly understood, which is a major obstacle hindering further improvements of this important fermentative process. In this study, a two-component system (TCS), BtrK/BtrR, was identified and demonstrated to positively regulate butanol tolerance and ABE solvent formation in Clostridium acetobutylicum, a representative species of solventogenic Clostridia. The transcriptomic analysis results showed that BtrK/BtrR has a pleiotropic regulatory function, affecting a large number of crucial genes and metabolic pathways. Of the differentially expressed genes, btrTM, encoding a putative ABC-type transporter (named BtrTM), was shown to be under the direct control of BtrR, the response regulator of the BtrK/BtrR TCS. Furthermore, BtrTM was shown to contribute to more butanol tolerance (46.5% increase) by overexpression, revealing a novel regulatory mechanism consisting of the BtrK/BtrR TCS and the BtrTM transporter in C. acetobutylicum. Based on these findings, we achieved faster growth and solvent production of C. acetobutylicum by overexpressing BtrK/BtrR or its direct target BtrTM, although no significant improvement in the final butanol titer and yield. These results further confirm the importance of BtrK/BtrR and BtrTM in this organism. Also, of significance, a specific number of btrR-btrT-btrM-btrK-like gene clusters were identified in other Clostridium species, including the pathogens Clostridium perfringens and Clostridium botulinum, indicating a broad role for this regulatory module in the class Clostridia.
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the small noncoding rna sr8384 determines solvent synthesis and cell growth in industrial solventogenic Clostridia
bioRxiv, 2019Co-Authors: Yunpeng Yang, Weihong Jiang, Nannan Lang, Huan Zhang, Lu Zhang, Changsheng ChaiAbstract:ABSTRACT Small noncoding RNAs (sncRNAs) are crucial regulatory molecules in organisms and are well known not only for their roles in the control of diverse essential biological processes but also for their value in genetic modification. However, to date, in gram-positive anaerobic solventogenic Clostridia (which are a group of important industrial bacteria with exceptional substrate and product diversity), sncRNAs remain minimally explored, leading to a lack of detailed understanding regarding these important molecules and their use as targets for genetic improvement. Here, we performed large-scale phenotypic screens of a transposon-mediated mutant library of Clostridium acetobutylicum, a typical solventogenic Clostridial species, and discovered a novel sncRNA (sr8384) that functions as a determinant positive regulator of growth and solvent synthesis. Comparative transcriptomic data combined with genetic and biochemical analyses revealed that sr8384 acts as a pleiotropic regulator and controls multiple targets that are associated with crucial biological processes, through direct or indirect interactions. Notably, modulation of the expression level of either sr8384 or its core target genes significantly increased the growth rate, solvent titer and productivity of the cells, indicating the importance of sr8384-mediated regulatory network in C. acetobutylicum. Furthermore, a homolog of sr8384 was discovered and proven to be functional in another important Clostridium species, C. beijerinckii, suggesting the potential broad role of this sncRNA in Clostridia. Our work showcases a previously unknown potent and complex role of sncRNAs in Clostridia, providing new opportunities for understanding and engineering these anaerobes, including pathogenic Clostridium species. IMPORTANCE The discovery of sncRNAs as new resources for functional studies and strain modifications are promising strategies in microorganisms. However, these crucial regulatory molecules have hardly been explored in industrially important solventogenic Clostridia. Here, we identified sr8384 as a novel determinant sncRNA controlling cellular performance of solventogenic Clostridium acetobutylicum and performed detailed functional analysis, which is the most in-depth study of sncRNAs in Clostridia to date. We reveal the pleiotropic function of sr8384 and its multiple direct and indirect crucial targets, which represents a valuable source for understanding and optimizing this anaerobe. Of note, manipulation of these targets leads to improved cell growth and solvent synthesis. Our findings provide a new perspective for future studies on regulatory sncRNAs in Clostridia.
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metabolic regulation in solventogenic Clostridia regulators mechanisms and engineering
Biotechnology Advances, 2018Co-Authors: Yunpeng Yang, Xiaoqun Nie, Weihong Jiang, Chen Yang, Yuqian JiangAbstract:Solventogenic Clostridia, a group of important industrial microorganisms, have exceptional substrate and product diversity, capable of producing a series of two-carbon and even long-chain chemicals and fuels by using various substrates, including sugars, cellulose and hemicellulose, and C1 gases. For the sake of in-depth understanding and engineering these anaerobic microorganisms for broader applications, studies on metabolic regulation of solventogenic Clostridia had been extensively carried out during the past ten years, based on the rapid development of various genetic tools. To date, a number of regulators that are essential for cell physiological and metabolic processes have been identified in Clostridia, and the relevant mechanisms have also been dissected, providing a wealth of valuable information for metabolic engineering. Here, we reviewed the latest research progresses on the metabolic regulation for chemical production and substrate utilization in solventogenic Clostridia, by focusing on three typical Clostridium species, the saccharolytic C. acetobutylicum and C. beijerinckii, as well as the gas-fermenting C. ljungdahlii. On this basis, future directions in the study and remodeling of Clostridial regulation systems, were proposed for effective modification of these industrially important anaerobes.
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Clostridia a flexible microbial platform for the production of alcohols
Current Opinion in Chemical Biology, 2016Co-Authors: Cong Ren, Weihong Jiang, Zhiqiang WenAbstract:Solventogenic Clostridia are native producers of ethanol and many higher alcohols employing a broad range of cheap renewable substrates, such as lignocellulosic materials and C1 gases (CO and CO2). These characteristics enable solventogenic Clostridia to act as flexible microbial platforms for the production of liquid biofuels. With the rapid development of genetic tools in recent years, the intrinsic intractability of Clostridia has been largely overcome, thus, engineering Clostridia for production of chemicals and fuels has attracted increasing interests. Here, we provide an overview of recent progress in the production of alcohols based on solventogenic Clostridia. Saccharolytic, cellulolytic and gas-fermenting Clostridia are discussed, with a special focus on strategies for metabolic engineering to enable and to improve Clostridia for the production of higher alcohols.
Gale Brightwell - One of the best experts on this subject based on the ideXlab platform.
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psychrophilic and psychrotrophic Clostridia sporulation and germination processes and their role in the spoilage of chilled vacuum packaged beef lamb and venison
International Journal of Food Science and Technology, 2010Co-Authors: Katharine H Adam, Steve Flint, Gale BrightwellAbstract:Summary Spoilage of beef, lamb and venison by psychrophilic and psychrotrophic Clostridial species renders meat unacceptable resulting in financial losses and reduced consumer confidence. A number of Clostridial strains, including Clostridium algidicarnis, Clostridium algidixylanolyticum, Clostridium estertheticum, Clostridium frigidicarnis and Clostridium gasigenes, have been implicated in red meat spoilage. Unlike other spoilers, these Clostridia are able to grow in anaerobic conditions and at chilled temperatures (some at −1.5 °C the optimal storage temperature for chilled red meat). The spoilage they cause is characterised by softening of the meat, production of large amounts of drip (exudates), offensive odours and in the case of C. estertheticum and C. gasigenes production of gas. Spoilage occurs following the introduction of Clostridial spores into vacuum packages during processing. Germination of spores is necessary for the growth of vegetative cells, which cause spoilage. Current mitigation strategies focus on good management practice within meat processing plants. However, this is not always sufficient to prevent spoilage. This review summarises the issues associated with meat spoilage because of psychrotolerant Clostridia and discusses areas that require further study.
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sources of psychrophilic and psychrotolerant Clostridia causing spoilage of vacuum packed chilled meats as determined by pcr amplification procedure
Journal of Applied Microbiology, 2009Co-Authors: D.m. Broda, J.a. Boerema, Gale BrightwellAbstract:Aims: To determine possible preslaughter and processing sources of psychrophilic and psychrotolerant Clostridia causing spoilage of vacuum-packed chilled meats. Methods and Results: Molecular methods based on the polymerase chain reaction (PCR) amplification of specific 16S rDNA fragments were used to detect the presence of Clostridium gasigenes, Clostridium estertheticum, Clostridium algidicarnis and Clostridium putrefaciens in a total of 357 samples collected from ten slaughter stock supply farms, slaughter stock, two lamb-processing plants, their environments, dressed carcasses and final vacuum-packed meat stored at –0·5°C for 5½ weeks. Clostridium gasigenes, C. estertheticum and C. algidicarnis/C. putrefaciens were commonly detected in farm, faeces, fleece and processing environmental samples collected at the slaughter floor operations prior to fleece removal, but all these micro-organisms were detected in only 4 out of 26 cooling floor and chiller environmental samples. One out of 42 boning room environmental samples tested positive for the presence of C. gasigenes and C. estertheticum, but 25 out of 42 of these samples were positive for C. algidicarnis/C. putrefaciens. Nearly all of the 31 faecal samples tested positive for the presence of C. gasigenes and C. estertheticum; however, only two of these samples were positive for C. algidicarnis and/or C. putrefaciens. Clostridial species that were subject to this investigation were frequently detected on chilled dressed carcasses. Conclusions: The major qualitative and quantitative differences between the results of PCR detection obtained with the primers specific for ‘blown pack’ -causing Clostridia (C. gasigenes and C. estertheticum) and those obtained with primers specific for C. algidicarnis and C. putrefaciens suggest that the control of meat spoilage caused by different groups of meat Clostridia is best approached individually for each group. Significance and Impact of the Study: This paper provides information significant for controlling meat spoilage-causing Clostridia in the meat-processing plants.