Mineral–microbe interactions indirectly affect the geochemical fluxes and biogeochemical cycling of a large number of elements. Among them are toxic heavy metals (e.g. chromium), radionuclides (uranium and technetium...Mineral–microbe interactions indirectly affect the geochemical fluxes and biogeochemical cycling of a large number of elements. Among them are toxic heavy metals (e.g. chromium), radionuclides (uranium and technetium), and nitrogen. Heavy metals and radionuclides enter the environment from various sources such as mining activity, nuclear weapons production, metallurgical and chemical industries. Other metals, such as lead, arsenic, antimony, and cadmium, are enriched in certain environments by either natural or anthropogenic processes. Because many of these metals and radionuclides are carcinogens, their release into the environment and their fate cause intense scientific and public concern and are the subject of substantial research. Nitrate enters the environment largely through agricultural activity. Human health risks from nitrate uptake from drinking water supplies run the gamut from increased cancer risk to birth defects.展开更多
The Maochang bauxite in Guizhou Province is one of the important aluminum ore deposits in southwestern China. Ferruginous spherules, measuring about a few microns across, were found in the transitional layer of the de...The Maochang bauxite in Guizhou Province is one of the important aluminum ore deposits in southwestern China. Ferruginous spherules, measuring about a few microns across, were found in the transitional layer of the deposit. The EDS and XRD results show that the microspherules are composed mostly of iron （hydr）oxide minerals （goethite） with only weak presence of aluminum and silicon. Occasionally, some pyrite micrograins with dissolved surface are found associated with goethite within the spherules. It is thus suggested that microspherules are linked to pyrite oxidization. It is also thought that microbial activities contribute not only to pyrite oxidization, but also to ball-like assemblage of the iron （hydr）oxides. The mechanism of the formation of ferruginous microspherules is also believed to be important in studying geomicrobiology of bauxite.展开更多
Tuberculosis(TB)is one of the deadliest infectious diseases in the world.The meta-bolic disease type 2 diabetes(T2D)significantly increases the risk of developing ac-tive TB.Effective new TB vaccine candidates and nov...Tuberculosis(TB)is one of the deadliest infectious diseases in the world.The meta-bolic disease type 2 diabetes(T2D)significantly increases the risk of developing ac-tive TB.Effective new TB vaccine candidates and novel therapeutic interventions are required to meet the challenges of global TB eradication.Recent evidence suggests that the microbiota plays a significant role in how the host responds to infection,in-jury and neoplastic changes.Animal models that closely reflect human physiology are crucial in assessing new treatments and to decipher the underlying immunological defects responsible for increased TB susceptibility in comorbid patients.In this study,using a diet-induced murine T2D model that reflects the etiopathogenesis of clinical T2D and increased TB susceptibility,we investigated how the intestinal microbiota may impact the development of T2D,and how the gut microbial composition changes following a very low-dose aerosol infection with Mycobacterium tuberculosis(Mtb).Our data revealed a substantial intestinal microbiota dysbiosis in T2D mice compared to non-diabetic animals.The observed differences were comparable to previous clini-cal reports in TB patients,in which it was shown that Mtb infection causes rapid loss of microbial diversity.Furthermore,diversity index and principle component analyses demonstrated distinct clustering of Mtb-infected non-diabetic mice vs.Mtb-infected T2D mice.Our findings support a broad applicability of T2D mice as a tractable small animal model for studying distinct immune parameters,microbiota and the immune-metabolome of TB/T2D comorbidity.This model may also enable answers to be found to critical outstanding questions about targeted interventions of the gut mi-crobiota and the gut-lung axis.展开更多
Carbon catabolite repression(CCR)plays a key role in many physiological and adaptive responses in a broad range of microorganisms that are commonly associated with eukaryotic hosts.When a mixture of different carbon s...Carbon catabolite repression(CCR)plays a key role in many physiological and adaptive responses in a broad range of microorganisms that are commonly associated with eukaryotic hosts.When a mixture of different carbon sources is available,CCR,a global regulatory mechanism,inhibits the expression and activity of cellular processes associated with utilization of secondary carbon sources in the presence of the preferred carbon source.CCR is known to be executed by completely different mechanisms in different bacteria,yeast,and fungi.In addition to regulating catabolic genes,CCR also appears to play a key role in the expression of genes involved in plant–microbe interactions.Here,we present a detailed overview of CCR mechanisms in various bacteria.We highlight the role of CCR in beneficial as well as deleterious plant–microbe interactions based on the available literature.In addition,we explore the global distribution of known regulatory mechanisms within bacterial genomes retrieved from public repositories and within metatranscriptomes obtained from different plant rhizospheres.By integrating the available literature and performing targeted meta-analyses,we argue that CCR-regulated substrate use preferences of microorganisms should be considered an important trait involved in prevailing plant–microbe interactions.展开更多
Plasma membrane （PM） H＋-ATPases are the primary pumps responsible for the establishment of cellular mem- brane potential in plants. In addition to regulating basic aspects of plant cell function, these enzymes cont...Plasma membrane （PM） H＋-ATPases are the primary pumps responsible for the establishment of cellular mem- brane potential in plants. In addition to regulating basic aspects of plant cell function, these enzymes contribute to sig- naling events in response to diverse environmental stimuli. Here, we focus on the roles of the PM H＋-ATPase during plant- pathogen interactions. PM H＋-ATPases are dynamically regulated during plant immune responses and recent quantitative proteomics studies suggest complex spatial and temporal modulation of PM H＋-ATPase activity during early pathogen recognition events. Additional data indicate that PM H＋-ATPases cooperate with the plant immune signaling protein RIN4 to regulate stomatal apertures during bacterial invasion of leaf tissue. Furthermore, pathogens have evolved mechanisms to manipulate PM H＋-ATPase activity during infection. Thus, these ubiquitous plant enzymes contribute to plant immune responses and are targeted by pathogens to increase plant susceptibility.展开更多
文摘Mineral–microbe interactions indirectly affect the geochemical fluxes and biogeochemical cycling of a large number of elements. Among them are toxic heavy metals (e.g. chromium), radionuclides (uranium and technetium), and nitrogen. Heavy metals and radionuclides enter the environment from various sources such as mining activity, nuclear weapons production, metallurgical and chemical industries. Other metals, such as lead, arsenic, antimony, and cadmium, are enriched in certain environments by either natural or anthropogenic processes. Because many of these metals and radionuclides are carcinogens, their release into the environment and their fate cause intense scientific and public concern and are the subject of substantial research. Nitrate enters the environment largely through agricultural activity. Human health risks from nitrate uptake from drinking water supplies run the gamut from increased cancer risk to birth defects.
文摘The Maochang bauxite in Guizhou Province is one of the important aluminum ore deposits in southwestern China. Ferruginous spherules, measuring about a few microns across, were found in the transitional layer of the deposit. The EDS and XRD results show that the microspherules are composed mostly of iron （hydr）oxide minerals （goethite） with only weak presence of aluminum and silicon. Occasionally, some pyrite micrograins with dissolved surface are found associated with goethite within the spherules. It is thus suggested that microspherules are linked to pyrite oxidization. It is also thought that microbial activities contribute not only to pyrite oxidization, but also to ball-like assemblage of the iron （hydr）oxides. The mechanism of the formation of ferruginous microspherules is also believed to be important in studying geomicrobiology of bauxite.
基金the National Health and Medical Research Council(NHMRC)through a CJ Martin Biomedical Early Career Fellowship(grant number APP1052764)a Career Development Fellowship(grant number APP1140709)+2 种基金a New Investigator Project Grant(grant num-ber APP1120808)an Australian Institute of Tropical Health and Medicine(AITHM)Capacity Building Grant(grant number 15031)to A.K&NKHDS was supported by an AITHM scholarship.
文摘Tuberculosis(TB)is one of the deadliest infectious diseases in the world.The meta-bolic disease type 2 diabetes(T2D)significantly increases the risk of developing ac-tive TB.Effective new TB vaccine candidates and novel therapeutic interventions are required to meet the challenges of global TB eradication.Recent evidence suggests that the microbiota plays a significant role in how the host responds to infection,in-jury and neoplastic changes.Animal models that closely reflect human physiology are crucial in assessing new treatments and to decipher the underlying immunological defects responsible for increased TB susceptibility in comorbid patients.In this study,using a diet-induced murine T2D model that reflects the etiopathogenesis of clinical T2D and increased TB susceptibility,we investigated how the intestinal microbiota may impact the development of T2D,and how the gut microbial composition changes following a very low-dose aerosol infection with Mycobacterium tuberculosis(Mtb).Our data revealed a substantial intestinal microbiota dysbiosis in T2D mice compared to non-diabetic animals.The observed differences were comparable to previous clini-cal reports in TB patients,in which it was shown that Mtb infection causes rapid loss of microbial diversity.Furthermore,diversity index and principle component analyses demonstrated distinct clustering of Mtb-infected non-diabetic mice vs.Mtb-infected T2D mice.Our findings support a broad applicability of T2D mice as a tractable small animal model for studying distinct immune parameters,microbiota and the immune-metabolome of TB/T2D comorbidity.This model may also enable answers to be found to critical outstanding questions about targeted interventions of the gut mi-crobiota and the gut-lung axis.
基金This work was supported by the French National Research Agency(ANR-18-CE32-0005,DIORE).
文摘Carbon catabolite repression(CCR)plays a key role in many physiological and adaptive responses in a broad range of microorganisms that are commonly associated with eukaryotic hosts.When a mixture of different carbon sources is available,CCR,a global regulatory mechanism,inhibits the expression and activity of cellular processes associated with utilization of secondary carbon sources in the presence of the preferred carbon source.CCR is known to be executed by completely different mechanisms in different bacteria,yeast,and fungi.In addition to regulating catabolic genes,CCR also appears to play a key role in the expression of genes involved in plant–microbe interactions.Here,we present a detailed overview of CCR mechanisms in various bacteria.We highlight the role of CCR in beneficial as well as deleterious plant–microbe interactions based on the available literature.In addition,we explore the global distribution of known regulatory mechanisms within bacterial genomes retrieved from public repositories and within metatranscriptomes obtained from different plant rhizospheres.By integrating the available literature and performing targeted meta-analyses,we argue that CCR-regulated substrate use preferences of microorganisms should be considered an important trait involved in prevailing plant–microbe interactions.
文摘Plasma membrane （PM） H＋-ATPases are the primary pumps responsible for the establishment of cellular mem- brane potential in plants. In addition to regulating basic aspects of plant cell function, these enzymes contribute to sig- naling events in response to diverse environmental stimuli. Here, we focus on the roles of the PM H＋-ATPase during plant- pathogen interactions. PM H＋-ATPases are dynamically regulated during plant immune responses and recent quantitative proteomics studies suggest complex spatial and temporal modulation of PM H＋-ATPase activity during early pathogen recognition events. Additional data indicate that PM H＋-ATPases cooperate with the plant immune signaling protein RIN4 to regulate stomatal apertures during bacterial invasion of leaf tissue. Furthermore, pathogens have evolved mechanisms to manipulate PM H＋-ATPase activity during infection. Thus, these ubiquitous plant enzymes contribute to plant immune responses and are targeted by pathogens to increase plant susceptibility.
