Freshwater harmful algal blooms are often dominated by Microcystis,a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity.We have previously shown that this genetic ...Freshwater harmful algal blooms are often dominated by Microcystis,a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity.We have previously shown that this genetic diversity and the presence of a microbiome of heterotrophic bacteria influences competitive interactions with eukaryotic phytoplankton.In this study,we sought to explain these observations by characterizing Monod equation parameters for resource usage(maximum growth rateμmax,half-saturation value for growth Ks,and quota)as a function of N and P levels for four strains(NIES-843,PCC 9701,PCC 7806[WT],and PCC 7806ΔmcyB)in presence and absence of a microbiome derived from Microcystis isolated from Lake Erie.Results indicated limited differences in maximum growth rates but more pronounced differences in half-saturation values among Microcystis strains.The largest impact of the microbiome was reducing the minimal nitrogen concentration sustaining growth and reducing half saturation values,with variable results depending on the Microcystis strain.Microcystis strains also differed from each other in their N and P quotas and the extent to which microbiome presence affected them.Our data highlight the importance of the microbiome in altering Microcystis-intrinsic traits,strain competitive hierarchies,and thus bloom dynamics.As quota,μmax,and Ks are commonly used in models for harmful algal blooms,our data suggest that model improvement may be possible by incorporating genotype dependencies of resource-use parameters.展开更多
The intestinal tract is inhabited by a tremendous number of microorganisms,termed the gut microbiota.These microorganisms live in a mutualistic relationship with their host and assist in the degradation of complex car...The intestinal tract is inhabited by a tremendous number of microorganisms,termed the gut microbiota.These microorganisms live in a mutualistic relationship with their host and assist in the degradation of complex carbohydrates.Although the gut microbiota is generally considered beneficial,the vast number of microbial cells also form a permanent threat to the host.Thus,the intestinal epithelium is covered with a dense layer of mucus to prevent translocation of the gut microbiota into underlying tissues.Intestinal mucus is an organized glycoprotein network with a host-specific glycan structure.While the mucus layer has long been considered a passive,host-designed barrier,recent studies showed that maturation and function of the mucus layer are strongly influenced by the gut microbiota.In return,the glycan repertoire of mucins can select for distinct mucosa-associated bacteria that are able to bind or degrade specific mucin glycans as a nutrient source.Because the intestinal mucus layer is at the crucial interface between host and microbes,its breakdown leads to gut bacterial encroachment that can eventually cause inflammation and infection.Accordingly,a dysfunctional mucus layer has been observed in colitis in mice and humans.Moreover,the increased consumption of a low-fiber Western-style diet in our modern society has recently been demonstrated to cause bacteria-mediated defects of the intestinal mucus layer.Here,I will review current knowledge on the interaction between gut bacteria and the intestinal mucus layer in health and disease.Understanding the molecular details of this host–microbe interaction may contribute to the development of novel treatment options for diseases involving a dysfunctional mucus layer,such as ulcerative colitis.展开更多
The brown planthopper,Nilaparvata lugens,is one of the main insect pests of rice.The N.lugens gene NICYP4CE1 encodes cytochrome P450 monooxygenase(P450),which is a key enzyme in the metabolism of the insecticide imida...The brown planthopper,Nilaparvata lugens,is one of the main insect pests of rice.The N.lugens gene NICYP4CE1 encodes cytochrome P450 monooxygenase(P450),which is a key enzyme in the metabolism of the insecticide imidacloprid.Previous research has suggested that the expression of NICYP4CEI is induced by imidacloprid stress,but the effect of bacterial symbionts on its expression has not been determined.The results of this study show that exposure to subtoxic imidacloprid changed the structure of the bacterial symbiont community in N.lugens.Specifically,the total bacterial content increased but the bacterial species diversity significantly decreased.Wolbachia accounted for the largest proportion of bacteria in N.lugens;its abundance significantly increased after subtoxic imidacloprid exposure.The transcript level of NICYP4CEI was significantly increased by imidacloprid,but this effect was significantly weakened after Wolbachia was cleared with tetracycline.This result suggests that Wolbachia enhances the expression of N1CYP4CE1 to promote the detoxification metabolic response to imidacloprid stress.Understanding the effect of bacterial symbionts on gene expression in the host provides a new perspective on interactions between insecticides and their target insect pests,and highlights that subtoxic imidacloprid exposure may raise the risk of insecticide resistance by altering the structure of bacterial symbiont communities.展开更多
Recent research often lauds the services and beneficial effects of host-associated microbes on animals.However,hosting these microbes may come at a cost.For example,germ-free and antibiotic-treated birds generally gro...Recent research often lauds the services and beneficial effects of host-associated microbes on animals.However,hosting these microbes may come at a cost.For example,germ-free and antibiotic-treated birds generally grow faster than their conventional counterparts.In the wild,juvenile body size is correlated with survival,so hosting a microbiota may incur a fitness cost.Avian altricial nestlings represent an interesting study system in which to investigate these interactions,given that they exhibit the fastest growth rates among vertebrates,and growth is limited by their digestive capacity.We investigated whether reduction and restructuring of the microbiota by antibiotic treatment would:(i)increase growth and food conversion efficiency in nestling house sparrows(Passer domesticus);(ii)alter aspects of gut anatomy or function(particularly activities of digestive carbohydrases and their regulation in response to dietary change);and(iii)whether there were correlations between relative abundances of microbial taxa,digestive function and nestling growth.Antibiotic treatment significantly increased growth and food conversion efficiency in nestlings.Antibiotics did not alter aspects of gut anatomy that we considered but depressed intestinal maltase activity.There were no significant correlations between abundances of microbial taxa and aspects of host physiology.Overall,we conclude that microbial-induced growth limitation in developing birds is not driven by interactions with digestive capacity.Rather,decreased energetic and material costs of immune function or beneficial effects from microbes enriched under antibiotic treatment may underlie these effects.Understanding the costs and tradeoffs of hosting gut microbial communities represents an avenue of future research.展开更多
During infections,bacteria stimulate host cells to produce and release histamine,which is a key mediator of vital cellular processes in animals.However,the mechanisms underlying the bacterial cell’s ability to sense ...During infections,bacteria stimulate host cells to produce and release histamine,which is a key mediator of vital cellular processes in animals.However,the mechanisms underlying the bacterial cell’s ability to sense and respond to histamine are poorly understood.Herein,we show that HinK,a Lys R-type transcriptional regulator,is required to evoke responses to histamine in Pseudomonas aeruginosa,an important human pathogen.HinK directly binds to and activates the promoter of genes involved in histamine uptake and metabolism,iron acquisition,and Pseudomonas quinolone signal(PQS)biosynthesis.The transcriptional regulatory activity of HinK is induced when histamine is present,and it occurs when HinK binds with imidazole-4-acetic acid(Im AA),a histamine metabolite whose production in P.aeruginosa depends on the HinK-activated histamine uptake and utilization operon hin DAC-pa0222.Importantly,the inactivation of HinK inhibits diverse pathogenic phenotypes of P.aeruginosa.These results suggest that histamine acts as an interkingdom signal and provide insights into the mechanism used by pathogenic bacteria to exploit host regulatory signals to promote virulence.展开更多
Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspect...Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspects of morphology,autonomy,physiology,behavior,and life cycle.The social bee gut bacteria exhibit host specificity that is likely a result of long-term co-evolution.The unique life cycle of bumblebees is key for the acquisition and development of their gut microbiota,and affects the strain-level diversity of the core bacterial species.Studies on bumblebee gut bacteria show that they retain less functional capacity for carbohydrate metabolism compared with that of the honeybee.We discuss the potential roles of the bumblebee gut microbiota against pathogenic threats and the application of host-specific probiotics for bumblebees.Given the advantages of the bumblebee microbiome,including the simple structure and host specificity,and the ease of manipulating bumblebee colonies,we propose that bumblebees may provide a valuable system for understanding the general principles of host-microbe interactions,gut-brain axis,and vertical transmission.展开更多
基金supported by funding from the NOAA Great Lakes Omics program distributed through the NOAA Cooperative Agreement with the Cooperative Institute for Great Lakes Research (CIGLR)at the University of Michigan (NA17OAR4320152 and NA22OAR4320150 to VJD,GJD,and CG)the National Science Foundation (Division of Environmental Biology-1737680)to VJD.
文摘Freshwater harmful algal blooms are often dominated by Microcystis,a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity.We have previously shown that this genetic diversity and the presence of a microbiome of heterotrophic bacteria influences competitive interactions with eukaryotic phytoplankton.In this study,we sought to explain these observations by characterizing Monod equation parameters for resource usage(maximum growth rateμmax,half-saturation value for growth Ks,and quota)as a function of N and P levels for four strains(NIES-843,PCC 9701,PCC 7806[WT],and PCC 7806ΔmcyB)in presence and absence of a microbiome derived from Microcystis isolated from Lake Erie.Results indicated limited differences in maximum growth rates but more pronounced differences in half-saturation values among Microcystis strains.The largest impact of the microbiome was reducing the minimal nitrogen concentration sustaining growth and reducing half saturation values,with variable results depending on the Microcystis strain.Microcystis strains also differed from each other in their N and P quotas and the extent to which microbiome presence affected them.Our data highlight the importance of the microbiome in altering Microcystis-intrinsic traits,strain competitive hierarchies,and thus bloom dynamics.As quota,μmax,and Ks are commonly used in models for harmful algal blooms,our data suggest that model improvement may be possible by incorporating genotype dependencies of resource-use parameters.
基金B.O.S.is supported by a Long-Term Fellowship from the Human Frontier Science Program(LT000109/2014).
文摘The intestinal tract is inhabited by a tremendous number of microorganisms,termed the gut microbiota.These microorganisms live in a mutualistic relationship with their host and assist in the degradation of complex carbohydrates.Although the gut microbiota is generally considered beneficial,the vast number of microbial cells also form a permanent threat to the host.Thus,the intestinal epithelium is covered with a dense layer of mucus to prevent translocation of the gut microbiota into underlying tissues.Intestinal mucus is an organized glycoprotein network with a host-specific glycan structure.While the mucus layer has long been considered a passive,host-designed barrier,recent studies showed that maturation and function of the mucus layer are strongly influenced by the gut microbiota.In return,the glycan repertoire of mucins can select for distinct mucosa-associated bacteria that are able to bind or degrade specific mucin glycans as a nutrient source.Because the intestinal mucus layer is at the crucial interface between host and microbes,its breakdown leads to gut bacterial encroachment that can eventually cause inflammation and infection.Accordingly,a dysfunctional mucus layer has been observed in colitis in mice and humans.Moreover,the increased consumption of a low-fiber Western-style diet in our modern society has recently been demonstrated to cause bacteria-mediated defects of the intestinal mucus layer.Here,I will review current knowledge on the interaction between gut bacteria and the intestinal mucus layer in health and disease.Understanding the molecular details of this host–microbe interaction may contribute to the development of novel treatment options for diseases involving a dysfunctional mucus layer,such as ulcerative colitis.
基金This work was supported by the National Natural Science Foundation of China(31871991)the Natural Science Foundation of Hubei Province(2019CFB471)the Fundamental Research Funds for the Central Universities(2662018JC049).
文摘The brown planthopper,Nilaparvata lugens,is one of the main insect pests of rice.The N.lugens gene NICYP4CE1 encodes cytochrome P450 monooxygenase(P450),which is a key enzyme in the metabolism of the insecticide imidacloprid.Previous research has suggested that the expression of NICYP4CEI is induced by imidacloprid stress,but the effect of bacterial symbionts on its expression has not been determined.The results of this study show that exposure to subtoxic imidacloprid changed the structure of the bacterial symbiont community in N.lugens.Specifically,the total bacterial content increased but the bacterial species diversity significantly decreased.Wolbachia accounted for the largest proportion of bacteria in N.lugens;its abundance significantly increased after subtoxic imidacloprid exposure.The transcript level of NICYP4CEI was significantly increased by imidacloprid,but this effect was significantly weakened after Wolbachia was cleared with tetracycline.This result suggests that Wolbachia enhances the expression of N1CYP4CE1 to promote the detoxification metabolic response to imidacloprid stress.Understanding the effect of bacterial symbionts on gene expression in the host provides a new perspective on interactions between insecticides and their target insect pests,and highlights that subtoxic imidacloprid exposure may raise the risk of insecticide resistance by altering the structure of bacterial symbiont communities.
基金Funding was provided by the National Science Foundation(IOS1354893 to W.H.K.)the National Institutes of Health(T32DK007673 Training Grant to K.D.K.)grants from Consejo Nacional de Investigaciones Científicas y Técnicas PIP 834 and UNSL CyT 9502 to E.C.V.
文摘Recent research often lauds the services and beneficial effects of host-associated microbes on animals.However,hosting these microbes may come at a cost.For example,germ-free and antibiotic-treated birds generally grow faster than their conventional counterparts.In the wild,juvenile body size is correlated with survival,so hosting a microbiota may incur a fitness cost.Avian altricial nestlings represent an interesting study system in which to investigate these interactions,given that they exhibit the fastest growth rates among vertebrates,and growth is limited by their digestive capacity.We investigated whether reduction and restructuring of the microbiota by antibiotic treatment would:(i)increase growth and food conversion efficiency in nestling house sparrows(Passer domesticus);(ii)alter aspects of gut anatomy or function(particularly activities of digestive carbohydrases and their regulation in response to dietary change);and(iii)whether there were correlations between relative abundances of microbial taxa,digestive function and nestling growth.Antibiotic treatment significantly increased growth and food conversion efficiency in nestlings.Antibiotics did not alter aspects of gut anatomy that we considered but depressed intestinal maltase activity.There were no significant correlations between abundances of microbial taxa and aspects of host physiology.Overall,we conclude that microbial-induced growth limitation in developing birds is not driven by interactions with digestive capacity.Rather,decreased energetic and material costs of immune function or beneficial effects from microbes enriched under antibiotic treatment may underlie these effects.Understanding the costs and tradeoffs of hosting gut microbial communities represents an avenue of future research.
基金supported by the Ministry of Science and Technology(MOST)of China(2016YFA0501503 and 2019ZX09721001-004-003)the National Natural Science Foundation of China(31670136,31870127,and 81861138047)+1 种基金the Science and Technology Commission of Shanghai Municipality(19JC1416400)the State Key Laboratory of Drug Research(SIMM2003ZZ-03)。
文摘During infections,bacteria stimulate host cells to produce and release histamine,which is a key mediator of vital cellular processes in animals.However,the mechanisms underlying the bacterial cell’s ability to sense and respond to histamine are poorly understood.Herein,we show that HinK,a Lys R-type transcriptional regulator,is required to evoke responses to histamine in Pseudomonas aeruginosa,an important human pathogen.HinK directly binds to and activates the promoter of genes involved in histamine uptake and metabolism,iron acquisition,and Pseudomonas quinolone signal(PQS)biosynthesis.The transcriptional regulatory activity of HinK is induced when histamine is present,and it occurs when HinK binds with imidazole-4-acetic acid(Im AA),a histamine metabolite whose production in P.aeruginosa depends on the HinK-activated histamine uptake and utilization operon hin DAC-pa0222.Importantly,the inactivation of HinK inhibits diverse pathogenic phenotypes of P.aeruginosa.These results suggest that histamine acts as an interkingdom signal and provide insights into the mechanism used by pathogenic bacteria to exploit host regulatory signals to promote virulence.
基金This work was supported by the National Key R&D Pro-gram of China(Grant No.2019YFA0906500)National Natural Science Foundation of China Project 32170495.
文摘Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspects of morphology,autonomy,physiology,behavior,and life cycle.The social bee gut bacteria exhibit host specificity that is likely a result of long-term co-evolution.The unique life cycle of bumblebees is key for the acquisition and development of their gut microbiota,and affects the strain-level diversity of the core bacterial species.Studies on bumblebee gut bacteria show that they retain less functional capacity for carbohydrate metabolism compared with that of the honeybee.We discuss the potential roles of the bumblebee gut microbiota against pathogenic threats and the application of host-specific probiotics for bumblebees.Given the advantages of the bumblebee microbiome,including the simple structure and host specificity,and the ease of manipulating bumblebee colonies,we propose that bumblebees may provide a valuable system for understanding the general principles of host-microbe interactions,gut-brain axis,and vertical transmission.
