Quorum sensing(QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell s...Quorum sensing(QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell signalling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminally fistulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers(AI) both in vivo and in vitro and to clone the lux S gene that encoded autoinducer-2(AI-2) synthase of microbial samples that were collected from the rumen of goats. Neutral detergent fiber(NDF) and soluble starch were the two types of substrates that were used for in vitro fermentation. The fermented fluid samples were collected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones(AHLs) activity was determined using gas chromatography-mass spectrometer(GC-MS) analysis. However, none of the rumen fluid extracts that were collected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using a Vibrio harveyi BB170 bioassay, was negative in all samples that were collected from the goat rumen and from in vitro fermentation fluids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal fluids obtained from in vitro fermentation at different sampling time-points. However, the homologues of lux S in Prevotella ruminicola were cloned from in vivo and in vitro ruminal fluids. We concluded that AHLs and AI-2 could not be detected in in vivo and in vitro ruminal fluids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each other via AI-2-mediated QS because of the presence of lux S.展开更多
This study investigated if the addition of urea (U), molasses (M) or their 1:1 (v/v) mixture during ensiling increases the nutritional value of forage from four fodder trees (Prunus persica, Leucaena esculenta, Acacia...This study investigated if the addition of urea (U), molasses (M) or their 1:1 (v/v) mixture during ensiling increases the nutritional value of forage from four fodder trees (Prunus persica, Leucaena esculenta, Acacia farnesiana, and Prunus domestica). Forage samples of fodder trees were collected in triplicate (three individual samples of each species) and subjected to an in vitro gas production (GP) procedure. Fermentation at 24 h (GP 24), short-chain volatile fatty acids (SCFA), and microbial crude protein production (MCP), in vitro organic matter digestibility (OMD), metabolizable energy (ME) and dry matter degradability (DMD) were estimated. Forage samples were incubated for 72 h in an incubator at 39oC and the volume of GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48, and 72 h of incubation using the reading pressure technique. The rumen fermentation profiles were highest for P. persica, which showed the highest (P<0.0001) DMD, ME, OMD, SCFA, GP 24 and MCP. On the other hand L. esculenta had the lowest (P<0.0001) DMD, SCFA, MCP; P. domestica had the lowest (P<0.0001) OMD. The addition of M to silage increased (P<0.0001) ME and OMD, as well as GP. However, the addition of U and the mixture of U and M reduced (P<0.0001) DMD, ME, OMD, SCFA, GY 24 and MCP. These results show that P. persica has the highest nutritive value and L. esculenta the lowest for ruminants. Additionally, the addition of M to forage from fodder trees increases rumen GP and fermentation, which may improve nutrient utilization in ruminants.展开更多
基金financially support of the Chinese Academy of Sciences (KZCX2-YW-455)the CAS/SAFEA International Partnership Program for Creative Research Teams,China (KZCX2-YW-T07) and K C Wong Education, Hong Kong
文摘Quorum sensing(QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell signalling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminally fistulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers(AI) both in vivo and in vitro and to clone the lux S gene that encoded autoinducer-2(AI-2) synthase of microbial samples that were collected from the rumen of goats. Neutral detergent fiber(NDF) and soluble starch were the two types of substrates that were used for in vitro fermentation. The fermented fluid samples were collected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones(AHLs) activity was determined using gas chromatography-mass spectrometer(GC-MS) analysis. However, none of the rumen fluid extracts that were collected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using a Vibrio harveyi BB170 bioassay, was negative in all samples that were collected from the goat rumen and from in vitro fermentation fluids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal fluids obtained from in vitro fermentation at different sampling time-points. However, the homologues of lux S in Prevotella ruminicola were cloned from in vivo and in vitro ruminal fluids. We concluded that AHLs and AI-2 could not be detected in in vivo and in vitro ruminal fluids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each other via AI-2-mediated QS because of the presence of lux S.
基金supported by the SEP (PROMEP), Mexico(PROMEP 103.5/09/4195)
文摘This study investigated if the addition of urea (U), molasses (M) or their 1:1 (v/v) mixture during ensiling increases the nutritional value of forage from four fodder trees (Prunus persica, Leucaena esculenta, Acacia farnesiana, and Prunus domestica). Forage samples of fodder trees were collected in triplicate (three individual samples of each species) and subjected to an in vitro gas production (GP) procedure. Fermentation at 24 h (GP 24), short-chain volatile fatty acids (SCFA), and microbial crude protein production (MCP), in vitro organic matter digestibility (OMD), metabolizable energy (ME) and dry matter degradability (DMD) were estimated. Forage samples were incubated for 72 h in an incubator at 39oC and the volume of GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48, and 72 h of incubation using the reading pressure technique. The rumen fermentation profiles were highest for P. persica, which showed the highest (P<0.0001) DMD, ME, OMD, SCFA, GP 24 and MCP. On the other hand L. esculenta had the lowest (P<0.0001) DMD, SCFA, MCP; P. domestica had the lowest (P<0.0001) OMD. The addition of M to silage increased (P<0.0001) ME and OMD, as well as GP. However, the addition of U and the mixture of U and M reduced (P<0.0001) DMD, ME, OMD, SCFA, GY 24 and MCP. These results show that P. persica has the highest nutritive value and L. esculenta the lowest for ruminants. Additionally, the addition of M to forage from fodder trees increases rumen GP and fermentation, which may improve nutrient utilization in ruminants.
