[Objective]This study aimed to determine the number of microorganisms of cotton rhizosphere in a soil at various amounts of applied nitrogen fertilizer in a red date-cotton intercropping system. [Method] In the field ...[Objective]This study aimed to determine the number of microorganisms of cotton rhizosphere in a soil at various amounts of applied nitrogen fertilizer in a red date-cotton intercropping system. [Method] In the field experiment, nitrogen fer-tilizer was applied at 0, 150, 300, 450, 600, and 750 kg/hm2, respectively. The dy-namic changes of the populations of bacteria, fungi and actinomycetes at the rhizo-sphere of cotton intercropped with red date were investigated. [Result] Microbial populations significantly increased at nitrogen fertilizer of 300 and 450 kg/hm2 during bud, flowering and bol opening periods. The numbers of bacteria and actinomycetes were higher during flowering and bol opening stages than at bud stage. The num-ber of fungi slightly changed during the entire growth period. Appropriate amount of nitrogen fertilizer （300 to 600 kg/hm2） was favorable to the survival of the microor-ganisms in the soil under the intercropping system. [Conclusion] The study provides a guideline for screening and determining the optimum amount of applied nitrogen fertilizer.展开更多
[Objective] The aim was to investigate the changes in microbial population and soil enzyme activities in rhizosphere soil of two cultivars of Allium sativum L.at different growth stages.[Method]By using white garlic a...[Objective] The aim was to investigate the changes in microbial population and soil enzyme activities in rhizosphere soil of two cultivars of Allium sativum L.at different growth stages.[Method]By using white garlic and purple garlic as the experimental materials,the microbial population,and the activities of urease,acid phosphatase and catalase in their rhizosphere soil at different growth stages were measured.[Result]The root exudates of the two garlic cultivars could promote the growth of bacteria,fungi and actinomycetes,and indirectly increase the urease,acid phosphatase and catalase activities in the rhizosphere soil,thereby improving the turnover and circulation of the soil nutrition elements such as nitrogen and phosphorus,and providing a better micro-ecological environment for the later crop.[Conclusion]The study had provided theoretical basis for the ecological research on garlic used as a preceding crop.展开更多
The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios rangin...The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200（m/m）.Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/（mg MLVSS.hr）,respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.展开更多
A field experiment was conducted to study the combined effect of nutrient andpest managements on soil biomass phospholipid contents, functional biodiversity and substrateutilization patterns of soil microbial populati...A field experiment was conducted to study the combined effect of nutrient andpest managements on soil biomass phospholipid contents, functional biodiversity and substrateutilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N, Pand K fertilizers (as urea, calcium superphosphate and KCl respectively) were incorporated at 100,25, and 100 kg ha^(-1), respectively, and the various pesticides were applied at the recommendedrates. The results of the experiment demonstrated a decline in the microbial abundance and soilmicrobial biomass phospholipid contents with the advancement of crop growth, and significant changesin substrate utilization pattern of soil microbial population studied were observed with differentmanagement practices and at different growth stages. The principal component analysis (PCA) usingall 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicatingthat they have different patterns of carbon utilization under different habitats. The data showedthat diversity in microbial community continuously changed with the progression in crop stage,particularly at physiological maturity (PM) stage that was evident from the utilization of differentcarbon sources at various crop stages.展开更多
In order to investigate the effects of microorganisms and their urease activities in macrophytic root zones on pollutant removal, four small-scale plots (SSPs) of vertical/reverse-vertical flow wetlands were set up to...In order to investigate the effects of microorganisms and their urease activities in macrophytic root zones on pollutant removal, four small-scale plots (SSPs) of vertical/reverse-vertical flow wetlands were set up to determine: a) the relationship between the abundance of microorganisms in the root zones and water purification efficiency; and b) the relationship between urease activities in the root zones and pollutant removal in a constructed wetland system. Total numbers of the microbial population (bacteria, fungi, and actinomyces) along with urease activities in the macrophytic root zones were determined. In addition, the relationships between microbial populations and urease activities as well as the wastewater purification efficiencies of total phosphorus (TP), total Kjeldahl nitrogen (TKN), biochemical oxygen demand in 5 days (BOD5), and chemical oxygen demand (COD) were also analyzed. The results showed that there was a highly significant positive correlation (r = 0.9772, P ＜ 0.01) between the number of bacteria in the root zones and BOD5 removal efficiency and a significant negative correlation (r = -0.9092, P ＜ 0.05) between the number of fungi and the removal efficiency of TKN. Meanwhile, there was a significant positive correlation (r -- 0.8830, P ＜ 0.05) between urease activities in the root zones and the removal efficiency of TKN. Thus, during wastewater treatment in a constructed wetland system,microorganism and urease activities in the root zones were very important factors.展开更多
This study evaluated the impact of pig manure acidification on anaerobic treatment and composition of the fecal microbial community. According to the different chemical oxygen demand （COD） in the anaerobic treatment...This study evaluated the impact of pig manure acidification on anaerobic treatment and composition of the fecal microbial community. According to the different chemical oxygen demand （COD） in the anaerobic treatment processes, pig manure was diluted 4 times （×4）, 16 times （×16）, or 64 times （×64） and subjected to acidification. During the acidification process, pH, soluble chemical oxygen demand （SCOD）, volatile fatty acids （VFAs）, nitrogen （N）, phosphorus （P） and potassium （K） were determined along with microbial population dynamics. The pH of the three dilutions first declined, and then slowly increased. The total VFAs of x4 and xl6 dilutions peaked on day 15 and 20, respectively. The content of acetic acid, propanoic acid, butanoic acid and valeric acid of the × 4 dilution were 23.6, 11.4, 8.8 and 0.6 g/L respectively, and that of the xl6 dilution was 5.6, 2.3, 0.9 and 0.2 g/L respectively. Only acetic acid was detected in the ×64 dilution, and its level peaked on day 10. The results showed that the liquid pig manure was more suitable to enter the anaerobic methanogenic hioreactors after two weeks of acidification. During the acidification process, total P concentration increased during the first ten days, then dropped sharply, and rose again to a relatively high final concentration, while total N concentration rose initially and then declined. Based on the analysis of denaturing gradient gel electrophoresis （DGGE） and 16S rRNA gene clone library, we concluded that the acidification process reduced the number of pathogenic bacteria species in pig manure.展开更多
Food waste(FW)has been recognized as essential reservoir for resource recovery via anaerobic fermentation,which could also bring the potential risk of antibiotic resistance genes(ARGs)dissemination.Although the struct...Food waste(FW)has been recognized as essential reservoir for resource recovery via anaerobic fermentation,which could also bring the potential risk of antibiotic resistance genes(ARGs)dissemination.Although the structural deficiency of FW could be stimulated by enzymatic pretreatment to enhance fermentation efficiency,the influences of enzymatic pretreatment on ARGs fate and microbial metabolic pathways involved in ARGs dissemination have rarely been reported.This work proved that enzymatic pretreatment could effectively decrease the total abundance of ARGs(reduced by 13.8%-24.5%)during long-term FW fermentation.It was found that enzymatic pretreatment significantly reduced the ARGs belonging to the efflux pump,which might be ascribed to its ability to increase membrane permeability.Furthermore,enzymatic pretreatment was in favor of reducing microbial diversity and various potential ARGs host(e.g.,Methanosarcina,Clostridium,Prevotella,Parabacteroides).Also,this pretreatment remarkably up-regulated the genetic expressions involved in ABC transporter(e.g.,eryF and mntA)and down-regulated the genetic expressions that participated in DNA replication,two-component systems(e.g.,uphA and cckA),and quorum sensing(e.g.,rpfF and lsrG),thereby decreasing ARGs transmission.This study would expand the insight of the influences of pretreatment method on ARGs fate during FW fermentation,and offer practical guidance on the sustainable management of FW.展开更多
The study of soil microbial populations and diversity is an important way to understanding the soil energy process.In this study we analyzed the characteristics of soil microbial populations of the Tarim Desert Highwa...The study of soil microbial populations and diversity is an important way to understanding the soil energy process.In this study we analyzed the characteristics of soil microbial populations of the Tarim Desert Highway shelter-forest,by identifying microbial fatty acids and using methods of conventional cul-tivation.The results illustrated that the amount of soil microbial activity and the diversity of soil microbial fatty acid increased significantly with the plantation age of the shelter-forest;the soil microbial population was dominated by bacteria.The fatty acids of C14︰0,C15︰0,C16︰0,C17︰0,C18︰1ω9,C18︰0,C18︰2ω6 and C21︰0 were found to be dominant soil microbial fatty acids in the shelter-forest soil.Prin-cipal analysis and regression analysis showed that(1) concentrations of fatty acids of C14︰0,C16︰0 and C18︰0 could be used as indicators of total soil microbial population;(2) soil bacteria and actinomycetes populations were closely correlated with the amount of fatty acids of C15︰0 and C17︰0;and(3) soil fungi were closely correlated with the amount of fatty acids of C18︰1ω9 and C18︰2ω6.展开更多
This study was conducted to investigate the effect of Soybean Peptides(SPs) on ruminal fermentation and microbial diversity in vitro. Four levels of SPs supplements(0, 0.25%, 0.50% and 0.75% dry matter basis) were tes...This study was conducted to investigate the effect of Soybean Peptides(SPs) on ruminal fermentation and microbial diversity in vitro. Four levels of SPs supplements(0, 0.25%, 0.50% and 0.75% dry matter basis) were tested. p H, NH3-N, Neutral Detergent Fiber(NDF), Acid Detergent Fiber(ADF), Dry Matter Digestibility(DMD) and the Total Volatile Fatty Acid(TVFA) were measured at 6, 24, 48 h of in vitro mixed incubation the fluids. Microbial populations were determined at 24 h and Microbial Proteins(MCP) were determined at 24 and 48 h. The gas production after 48 h in vitro incubation presented linear growth(p<0.05) and the highest content was the level of 0.5% SPs(dry matter basis). NH3-N concentration reached the highest concentration with 0.75%(dry matter basis) at 48 h. p H linearly increased(linear, p<0.05) from 6 to 48 h. The digestion of DMD increased with increasing doses of SPs at 24 h. NDF and ADF linearly(p<0.01) decreased by adding SPs. The concentration of TVFA linearly increased(p<0.05) at 6, 24 and 48 h, and reached the highest concentration at the level of 0.75%(dry matter basis). SPs decreased(p<0.05) the molar proportion of acetate and propionate, respectively at 24 and 48 h. Acetat to Propionate ratio(A/P; linear, p<0.05) increased at 48 h, and reached the greatest value at the level of 0.75%(dry matter basis) at 48 h. The populations of rumen Ruminococcus flavefaciens(R. flavefaciens), Ruminococcusalbus(R. albus), Fibrobacter succinogenes(F. succinogenes), Butyrivibrio fibrisolvens(B. fibrisolvens), Streptococcus bovis(S.bovis), Ruminobacter amylophilus(R. amylophilus) and Succinimonas amylolytica(S. amylolytica) were analyzed based on the total rumen bacterial 16 S ribosomal deoxyribonucleic acid(r DNA). The relative abundance of R. flavefaciens and R. albus increased at 24 h, but the relative abundance of F. succinogenes decreased at this time. The incubation of SPs had no effect on the abundance of S. bovis and R. amylophilus. The relative abundance of B. fibrisolvens and S. amylolytica reached the greatest value(p<0.05) at middle doses of SPs inclusion at 24 h. The value of MCPs linearly increased(p<0.05) at 24 and 48 h. These results showed that SPs could improve in vitro fermentation and nutrient digestion of feed substrates, and had the ability to modulate the ruminal fermentation pattern by regulating the composition of functional rumen microbes. Hence, SPs might be a potential feed additive applied in the diets of ruminants.展开更多
Pure culture and pot culture experiments were carried out to study the effect of lanthanum (La) on bacteria, actinomyces and fungus, and some microbial physiological groups , nitrifier, azotobacter and phos- phobacter...Pure culture and pot culture experiments were carried out to study the effect of lanthanum (La) on bacteria, actinomyces and fungus, and some microbial physiological groups , nitrifier, azotobacter and phos- phobacteria, in a red soil taken form the Ecological Experimental Station of Red Soil, the Chinese Academy of Sciences, Jiangxi Province. LaCl3 was added into media at levels of 0, 25, 50, 100, 150, 200, 250 and 500 mg L-1 in the pure culture experiment, and into soil samples in porcelain pots before rice growing at levels of 0, 6, 30, 150, 300, 600 and 900 mg kg-1 dry soil in the pot culture experiment. The populations of the three soil microbes in the pure culture experiment decreased with the addition level of La, indicating that La was toxic to the soil microbes in pure culture, and the sensitivity of the 3 major microbial types to La was in a decreasing order of actinomyces > bacteria > fungus. In the pot experiment, La had slightly stimulative effect on soil bacteria and actinomyces when applied at low concentrations while had inhibitory effect on soil bacteria, actinomyces and fungus at high concentrations. When the concentration of La was low, soil azotobacter was stimulated slightly while soil nitrifier was stimulated strongly and the maximum increase was up to 50%. When the concentration of La was high, both soil azotobacter and nitrifier were inhibited, and the inhibition of La to the nitrifier increased with La concentration. La added at all the levels had stimulative effect on soil inorganic and organic phosphobatteria. Among the 4 physiological groups, soil nitrifier was most sensitive to La, so , it might be reasonable to assume that soil nitrifier was a sensitive indicator for evaluating the biological and environmental effects of rare earths.展开更多
The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cu...The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cubes（PUFC）, on which thermophilic desulfurization bacteria were attached. The thermophilic biofilter effectively reduced SO2 within 10 months of operation time, with a maximum elimination capacity of 48.29 g/m^3/hr.Temporal shifts in the microbial population in the thermophilic biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and deoxyribonucleic acid（DNA） sequence analysis. The substrate species and environmental conditions in the biofilter influenced the microbial population. Oxygen distribution in the PUFC was analyzed using a microelectrode. When the water-containing rate in PUFC was over 98%, the oxygen distribution presented aerobic–anoxic–aerobic states along the test route on the PUFC. The appearance of sulfate-reducing bacteria was caused by the anaerobic conditions and sulfate formation after 4 months of operation.展开更多
The experiment was conducted using a total of 1392 one-day-old, Cobb commercial male broilers to investigate the effects of a commercial probiotic addition in diet on growth, the development of the small intestine and...The experiment was conducted using a total of 1392 one-day-old, Cobb commercial male broilers to investigate the effects of a commercial probiotic addition in diet on growth, the development of the small intestine and microbial populations of broilers. Broilers were randomly allotted by BW to 1 of 6 replicate cages （29 chicks per cage） for each of 8 treatments in a randomized block design involving one factorial arrangement of treatments. Dietary treatments included the basal diet （including corn, soybean, rapeseed, cottonseed meal） added with 100 mg/kg antibiotic, 0%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%. The experiment last 42 d and divided into the starter period （1-21 d） and the finisher period （22-42 d）. The results showed that there were significant differences in broiler body weight （BW） （P〈0.001）, average daily feed intake （ADFI） （P=0.033）, relative length of the duodenum （P〈0.001）, jejunum （P=0.008）, ileum （P〈0.001） and the populations of lactobacillus （P〈0.001） and coliform （P〈0.001） in the rectum between the probiotics treatments and the control treatment only in the starter period of the trails. No significant differences were observed in intestinal morphology parameters in two periods of the experiment. Our results indicated that the probiotic was able to improve the performance of broiler chickens, and it was better in the starter period to be used than in the finisher period.展开更多
The objective of the present study was to evaluate the effect of feeding different levels of whole linseed,as a source of n-3 polyunsaturated fatty acids(PUFA), on ruminal fatty acid composition and microbial populati...The objective of the present study was to evaluate the effect of feeding different levels of whole linseed,as a source of n-3 polyunsaturated fatty acids(PUFA), on ruminal fatty acid composition and microbial population in the goat. Twenty-four crossbred Boer goats were assigned to 3 dietary treatments: LO(control), L10 and L20 containing 0,10%, or 20% whole linseed, respectively. The ruminal pH and concentration of total volatile fatty acids(VFA) were not affected by dietary treatments. The feeding of L10 and L20 diets produced higher(P < 0.05) molar proportions of acetate and lower(P < 0.05) molar proportions of butyrate and valerate than the LO diet. Molar proportions of myristic acid(C14:0) and palmitic acid(C16:0) were lower(P < 0.05) in the rumen of goats offered L10 and L20 diets than the control diet. However, stearic acid(C18:0), vaccenic acid(C18:1 trans-11), conjugated linoleic acid(CLA,C18:2 trans-10, cis-12) and a-lenolenic acid(C18:3 n-3) were higher(P < 0.05) in the rumen of goats fed L10 and L20 than L0. Both inclusion levels of linseed in the diet(L10 and L20) reduced the ruminal total bacteria, methanogens, and protozoa compared with LO(P < 0.05). The effect of the dietary treatments on cellulolytic bacteria, varied between the individual species. Both inclusion levels of linseed resulted in a significant decrease(P < 0.05) in the population of Fibrobacter succinogenes, and Rumunococus flavefaciens compared with LO, with no significant difference between the groups fed linseed diets. The population of Rumunococus albus was not affected by the different dietary treatments. It was concluded that inclusion of whole linseed in the diet of goats could increase the concentration of PUFA in the rumen, and decrease the population of F. succinogenes, R. flavefaciens, methanogens and protozoa in rumen liquid of goats.展开更多
Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed...Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed high concentrations of heavy metals in the order of Cr〉Fe〉Zn〉Ni〉Co〉Mn while ground water did not show any heavy metal contamination except Fe. Physico-chemical parameters of mine water samples showed deviation from those of normal water. Mine water harboured low microbial populations of bacteria, fungi and actinomycetes in comparison with mine adjacent water samples. The correlation of data between metals with physico-chemical parameters showed both positive and negative responses while that of metal and microbial population exhibited negative correlation. Bacterial strains isolated from chromite mine water exhibited high tolerance towards chromium and other heavy metals as well as antibiotics which could be used as an indicator of heavy metal pollution.展开更多
Plant growth-promoting rhizobacteria （PGPR） have been widely recognized as an important agent, especially as a biofertilizer, in agricultural systems. The objectives of this study were to select effective PGPR for C...Plant growth-promoting rhizobacteria （PGPR） have been widely recognized as an important agent, especially as a biofertilizer, in agricultural systems. The objectives of this study were to select effective PGPR for Chinese kale （Brassica oleracea var. alboglabra） cultivation and to investigate the effect of their inoculation on indigenous microbial community structure. The Bacillus sp. SUT1 and Pseudomonas sp. SUT19 were selected for determining the efficiency in promoting Chinese kale growth in both pot and field experiments. In the field experiment, PGPR amended with compost gave the highest yields among all treatments. The Chinese kale growth promotion may be directly affected by PGPR inoculation. The changes of microbial community structure in the rhizosphere of Chinese kale following PGPR inoculation were examined by denaturing gradient gel electrophoresis （DGGE） and principal coordinate analysis. The DGGE fingerprints of 16S rDNA amplified from total community DNA in the rhizosphere confirmed that our isolates were established in the rhizosphere throughout this study. The microbial community structures were slightly different among all the treatments, and the major changes depended on stages of plant growth. DNA sequencing of excised DGGE bands showed that the dominant species in microbial community structure in the rhizosphere were not mainly interfered by PGPR, but strongly influenced by plant development. The microbial diversity as revealed by diversity indices was not different between the PGPR-inoculated and uninoculated treatments. In addition, the rhizosphere soil had more influence on eubacterial diversity, whereas it did not affect archaebacterial and fungal diversities.展开更多
The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O_2 and H_2O. In present study, a microelectrode was applied to analyze O_2 in polyurethane foam cubes（PUFCs...The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O_2 and H_2O. In present study, a microelectrode was applied to analyze O_2 in polyurethane foam cubes（PUFCs） packed in a biofilter for SO_2 removal. The O_2 distribution varied with the density and water-containing rate（WCR） of PUFCs. The O_2 concentration dropped sharply from 10.2 to 0.8 mg/L from the surface to the center of a PUFC with 97.20%of WCR. The PUFCs with high WCR presented aerobic–anoxic–aerobic areas.Three-dimensional simulated images demonstrated that the structure of PUFCs with high WCR consisted of an aerobic ＂shell＂ and an anoxic ＂core＂, with high-density PUFCs featuring a larger anoxic area than low-density PUFCs. Moreover, the H_2O distribution in the PUFC was uneven and affected the O_2 concentration. Whereas aerobic bacteria were observed in the PUFC surface, facultative anaerobic microorganisms were found at the PUFC core, where the O_2 concentration was relatively low. O_2 and H_2O distributions differed in the PUFCs, and the distribution of microorganisms varied accordingly.展开更多
Recent advancements in single-cell genomic and transcriptomic sequencing,in situ sequencing,and molecular imaging-based technologies have facilitated the examination of heterogeneity within microbial communities at th...Recent advancements in single-cell genomic and transcriptomic sequencing,in situ sequencing,and molecular imaging-based technologies have facilitated the examination of heterogeneity within microbial communities at the single-cell level.These cutting-edge methodologies permit the capture of phenotypic and genotypic heterogeneity,as well as the spatial organization within microbial communities.This enables in-depth investigation into microbial dark matter,the evaluation of microbial responses to perturbations,and a comprehensive exploration of spatial functions involved in community assembly and social interactions within microbial communities.These interactions include inter-microbial relationships,bacteria-phage interactions,and host-microbe interactions.Here,we highlight the key technological breakthroughs achieved,elucidating the perspectives from which these technologies enable us to interpret microbial heterogeneity at the single-cell level.Additionally,we critically examine the limitations associated with these technologies.Furthermore,we explore how these methods could be combined and also their applications in future studies.The integration of these approaches holds great promise for increasing our understanding of the organization and function of microbes in complex ecosystems.展开更多
Soil ecosystem is experiencing stresses due to climate change,and soil inhabitants try to demonstrate their inherent resistance and resilience against those stresses.Application of nanomaterials as agricultural inputs...Soil ecosystem is experiencing stresses due to climate change,and soil inhabitants try to demonstrate their inherent resistance and resilience against those stresses.Application of nanomaterials as agricultural inputs could bring shifts in resistance and resilience patterns of soil microbes and associated enzymes,especially under short-term heat stress.With this background,the impacts of multi-walled carbon nanotube(MWCNT)on the resistance and resilience of soil biological indicators were evaluated.An incubation experiment was conducted with varied MWCNT concentrations(0,50,100,250,and 500 mg kg-1soil)for 90 d after 24-h heat stress at 48±2?C to assess the impacts of MWCNT on soil enzyme activities and microbial populations vis-à-vis their resistance and resilience indices under short-term exposure to heat stress.Enzyme activities were reduced after exposure to heat stress.Resistance indices of enzyme activities were enhanced by MWCNT application on day 1 after heat stress,whereas there was no recovery of enzyme activities after 90-d incubation.Like soil enzyme activities,resistance index values of soil microbial populations followed the similar trend and were improved by MWCNT application.Multi-walled carbon nanotube has the potential to improve resistance indices of soil enzyme activities and microbial populations under heat stress,although they could not recover to their original state during periodical incubation after heat stress.This study helps to understand the relative changes of biological indicators under MWCNT and their ability to withstand heat stress.展开更多
[Objective] The paper was to study the bioactive characteristics of soil microorganisms in different-aged orange plantations. [Method] Taking 010 cm deep soil in 3 orange plantations with different planting years in s...[Objective] The paper was to study the bioactive characteristics of soil microorganisms in different-aged orange plantations. [Method] Taking 010 cm deep soil in 3 orange plantations with different planting years in suburb of Yichang City as the test object, the variation rule of total organic carbon, total nitrogen, soil pH value, microbial biomass carbon, microbial biomass nitrogen, number of 3 main types of soil microbial flora, basal respiration, microbial entropy and metabolic entropy in differentaged orange plantations was studied. [Result] With the increase of planting years, the soil acidification of different-aged orange plantations was aggravating; total organic carbon and total nitrogen content increased first and then decreased; the total number of soil microorganism showed a downtrend, of which the number of bacteria decreased significantly, the number of actinomycetes had small changes, the number of fungi increased significantly, and the ratio of bacteria and fungi in soil （B/F） showed a decreasing trend. Soil microbial biomass carbon was fluctuated within a small range, whereas soil microbial biomass nitrogen decreased significantly; soil microbial entropy decreased significantly, and metabolic entropy showed an increasing trend. This indicated that the decrease of soil pH value affected the changes of soil microbial flora, microbial activity, microbial biomass carbon and nitrogen and soil major nutrients, and further affected the normal exertion of soil function. [Conclusion] The study explores soil nutrient characteristics and changes of microbial flora in test area, which will provide scientific basis for further study on orchard soil and orchard management.展开更多
Different kinds of mineral nutrients(NO_3-N, NH_4-N and PO_4-P) were applied in the simulated oil-polluted seawater for enhancing oil biodegradation in the N/P ratio 10∶1 and 20:1 Although indigenous microorganisms...Different kinds of mineral nutrients(NO_3-N, NH_4-N and PO_4-P) were applied in the simulated oil-polluted seawater for enhancing oil biodegradation in the N/P ratio 10∶1 and 20:1 Although indigenous microorganisms have the ability to degrade oil, adding nutrients accelerated biodegradation rates significantly. For the group amended with NO_3-N and PO_4-P in the ratio 10∶1, the reaction rate coefficient was 4 times higher than the natural biodegradation. Chemical and microbiological analysis showed that the optimal N/P ratio in the system is 10∶1, and microorganisms tend to utilize nitrate rather than ammonium as N source.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201003043-07)Scientific Research Program of Higher Education Institutions ofXinjiang Uygur Autonomous Region(XJEDU2012S14)+1 种基金National UndergraduateInnovative Training Project(201210758002)Fund for the Excellent Youth Scholars ofXinjiang Academy of Agricultural Sciences(xjnky-2012-009)~~
文摘[Objective]This study aimed to determine the number of microorganisms of cotton rhizosphere in a soil at various amounts of applied nitrogen fertilizer in a red date-cotton intercropping system. [Method] In the field experiment, nitrogen fer-tilizer was applied at 0, 150, 300, 450, 600, and 750 kg/hm2, respectively. The dy-namic changes of the populations of bacteria, fungi and actinomycetes at the rhizo-sphere of cotton intercropped with red date were investigated. [Result] Microbial populations significantly increased at nitrogen fertilizer of 300 and 450 kg/hm2 during bud, flowering and bol opening periods. The numbers of bacteria and actinomycetes were higher during flowering and bol opening stages than at bud stage. The num-ber of fungi slightly changed during the entire growth period. Appropriate amount of nitrogen fertilizer （300 to 600 kg/hm2） was favorable to the survival of the microor-ganisms in the soil under the intercropping system. [Conclusion] The study provides a guideline for screening and determining the optimum amount of applied nitrogen fertilizer.
基金Supported by Startup Foundation for Doctors of Jilin Agricultural University(2007021)~~
文摘[Objective] The aim was to investigate the changes in microbial population and soil enzyme activities in rhizosphere soil of two cultivars of Allium sativum L.at different growth stages.[Method]By using white garlic and purple garlic as the experimental materials,the microbial population,and the activities of urease,acid phosphatase and catalase in their rhizosphere soil at different growth stages were measured.[Result]The root exudates of the two garlic cultivars could promote the growth of bacteria,fungi and actinomycetes,and indirectly increase the urease,acid phosphatase and catalase activities in the rhizosphere soil,thereby improving the turnover and circulation of the soil nutrition elements such as nitrogen and phosphorus,and providing a better micro-ecological environment for the later crop.[Conclusion]The study had provided theoretical basis for the ecological research on garlic used as a preceding crop.
基金supported by the National Key Technologies R&D Program of China during the Eleventh Five-year Plan Period (No. 2009BAC57B01)the State Key Laboratory of Urban Water Resource and Environment(HIT) (No. QAK201006)
文摘The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200（m/m）.Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/（mg MLVSS.hr）,respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.
基金the National Natural Science Foundation of China.
文摘A field experiment was conducted to study the combined effect of nutrient andpest managements on soil biomass phospholipid contents, functional biodiversity and substrateutilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N, Pand K fertilizers (as urea, calcium superphosphate and KCl respectively) were incorporated at 100,25, and 100 kg ha^(-1), respectively, and the various pesticides were applied at the recommendedrates. The results of the experiment demonstrated a decline in the microbial abundance and soilmicrobial biomass phospholipid contents with the advancement of crop growth, and significant changesin substrate utilization pattern of soil microbial population studied were observed with differentmanagement practices and at different growth stages. The principal component analysis (PCA) usingall 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicatingthat they have different patterns of carbon utilization under different habitats. The data showedthat diversity in microbial community continuously changed with the progression in crop stage,particularly at physiological maturity (PM) stage that was evident from the utilization of differentcarbon sources at various crop stages.
基金Project supported by the National Science Fund for Distinguished Young Scholars of China (No. 39925007)the Biotechnology section of INCO-DC under the 4th Framework Program of the European Commission(No. ERBIC18CT960059).
文摘In order to investigate the effects of microorganisms and their urease activities in macrophytic root zones on pollutant removal, four small-scale plots (SSPs) of vertical/reverse-vertical flow wetlands were set up to determine: a) the relationship between the abundance of microorganisms in the root zones and water purification efficiency; and b) the relationship between urease activities in the root zones and pollutant removal in a constructed wetland system. Total numbers of the microbial population (bacteria, fungi, and actinomyces) along with urease activities in the macrophytic root zones were determined. In addition, the relationships between microbial populations and urease activities as well as the wastewater purification efficiencies of total phosphorus (TP), total Kjeldahl nitrogen (TKN), biochemical oxygen demand in 5 days (BOD5), and chemical oxygen demand (COD) were also analyzed. The results showed that there was a highly significant positive correlation (r = 0.9772, P ＜ 0.01) between the number of bacteria in the root zones and BOD5 removal efficiency and a significant negative correlation (r = -0.9092, P ＜ 0.05) between the number of fungi and the removal efficiency of TKN. Meanwhile, there was a significant positive correlation (r -- 0.8830, P ＜ 0.05) between urease activities in the root zones and the removal efficiency of TKN. Thus, during wastewater treatment in a constructed wetland system,microorganism and urease activities in the root zones were very important factors.
基金supported by the National Key Technology Research and Development Program of China during the 11th Five-Year Plan Period (No. 2008BADC4B01,2008BADC4B17)the National Water Pollution Control and Management Special Project of China (No.2008ZX07209-003)
文摘This study evaluated the impact of pig manure acidification on anaerobic treatment and composition of the fecal microbial community. According to the different chemical oxygen demand （COD） in the anaerobic treatment processes, pig manure was diluted 4 times （×4）, 16 times （×16）, or 64 times （×64） and subjected to acidification. During the acidification process, pH, soluble chemical oxygen demand （SCOD）, volatile fatty acids （VFAs）, nitrogen （N）, phosphorus （P） and potassium （K） were determined along with microbial population dynamics. The pH of the three dilutions first declined, and then slowly increased. The total VFAs of x4 and xl6 dilutions peaked on day 15 and 20, respectively. The content of acetic acid, propanoic acid, butanoic acid and valeric acid of the × 4 dilution were 23.6, 11.4, 8.8 and 0.6 g/L respectively, and that of the xl6 dilution was 5.6, 2.3, 0.9 and 0.2 g/L respectively. Only acetic acid was detected in the ×64 dilution, and its level peaked on day 10. The results showed that the liquid pig manure was more suitable to enter the anaerobic methanogenic hioreactors after two weeks of acidification. During the acidification process, total P concentration increased during the first ten days, then dropped sharply, and rose again to a relatively high final concentration, while total N concentration rose initially and then declined. Based on the analysis of denaturing gradient gel electrophoresis （DGGE） and 16S rRNA gene clone library, we concluded that the acidification process reduced the number of pathogenic bacteria species in pig manure.
基金This work was financially supported by the National Key Research and Development Program of China(No.2019YFC1906302)the Shanghai Natural Science Foundation(No.22ZR1466900)the China Postdoctoral Science Foundation(No.2021M692423).
文摘Food waste(FW)has been recognized as essential reservoir for resource recovery via anaerobic fermentation,which could also bring the potential risk of antibiotic resistance genes(ARGs)dissemination.Although the structural deficiency of FW could be stimulated by enzymatic pretreatment to enhance fermentation efficiency,the influences of enzymatic pretreatment on ARGs fate and microbial metabolic pathways involved in ARGs dissemination have rarely been reported.This work proved that enzymatic pretreatment could effectively decrease the total abundance of ARGs(reduced by 13.8%-24.5%)during long-term FW fermentation.It was found that enzymatic pretreatment significantly reduced the ARGs belonging to the efflux pump,which might be ascribed to its ability to increase membrane permeability.Furthermore,enzymatic pretreatment was in favor of reducing microbial diversity and various potential ARGs host(e.g.,Methanosarcina,Clostridium,Prevotella,Parabacteroides).Also,this pretreatment remarkably up-regulated the genetic expressions involved in ABC transporter(e.g.,eryF and mntA)and down-regulated the genetic expressions that participated in DNA replication,two-component systems(e.g.,uphA and cckA),and quorum sensing(e.g.,rpfF and lsrG),thereby decreasing ARGs transmission.This study would expand the insight of the influences of pretreatment method on ARGs fate during FW fermentation,and offer practical guidance on the sustainable management of FW.
基金funded by Western Doctoral Program of Chinese Academy of Sciences,the Innovation Project of Chinese Academy of Science (KZCX2-XB2-13)the National Natural Science Foundation of Xinjiang Uygur Autonomous Region (200821163), and Natural Science Foundation of China (40701098)
文摘The study of soil microbial populations and diversity is an important way to understanding the soil energy process.In this study we analyzed the characteristics of soil microbial populations of the Tarim Desert Highway shelter-forest,by identifying microbial fatty acids and using methods of conventional cul-tivation.The results illustrated that the amount of soil microbial activity and the diversity of soil microbial fatty acid increased significantly with the plantation age of the shelter-forest;the soil microbial population was dominated by bacteria.The fatty acids of C14︰0,C15︰0,C16︰0,C17︰0,C18︰1ω9,C18︰0,C18︰2ω6 and C21︰0 were found to be dominant soil microbial fatty acids in the shelter-forest soil.Prin-cipal analysis and regression analysis showed that(1) concentrations of fatty acids of C14︰0,C16︰0 and C18︰0 could be used as indicators of total soil microbial population;(2) soil bacteria and actinomycetes populations were closely correlated with the amount of fatty acids of C15︰0 and C17︰0;and(3) soil fungi were closely correlated with the amount of fatty acids of C18︰1ω9 and C18︰2ω6.
基金the China Agricultural Research System for providing facility and funds for experiment
文摘This study was conducted to investigate the effect of Soybean Peptides(SPs) on ruminal fermentation and microbial diversity in vitro. Four levels of SPs supplements(0, 0.25%, 0.50% and 0.75% dry matter basis) were tested. p H, NH3-N, Neutral Detergent Fiber(NDF), Acid Detergent Fiber(ADF), Dry Matter Digestibility(DMD) and the Total Volatile Fatty Acid(TVFA) were measured at 6, 24, 48 h of in vitro mixed incubation the fluids. Microbial populations were determined at 24 h and Microbial Proteins(MCP) were determined at 24 and 48 h. The gas production after 48 h in vitro incubation presented linear growth(p<0.05) and the highest content was the level of 0.5% SPs(dry matter basis). NH3-N concentration reached the highest concentration with 0.75%(dry matter basis) at 48 h. p H linearly increased(linear, p<0.05) from 6 to 48 h. The digestion of DMD increased with increasing doses of SPs at 24 h. NDF and ADF linearly(p<0.01) decreased by adding SPs. The concentration of TVFA linearly increased(p<0.05) at 6, 24 and 48 h, and reached the highest concentration at the level of 0.75%(dry matter basis). SPs decreased(p<0.05) the molar proportion of acetate and propionate, respectively at 24 and 48 h. Acetat to Propionate ratio(A/P; linear, p<0.05) increased at 48 h, and reached the greatest value at the level of 0.75%(dry matter basis) at 48 h. The populations of rumen Ruminococcus flavefaciens(R. flavefaciens), Ruminococcusalbus(R. albus), Fibrobacter succinogenes(F. succinogenes), Butyrivibrio fibrisolvens(B. fibrisolvens), Streptococcus bovis(S.bovis), Ruminobacter amylophilus(R. amylophilus) and Succinimonas amylolytica(S. amylolytica) were analyzed based on the total rumen bacterial 16 S ribosomal deoxyribonucleic acid(r DNA). The relative abundance of R. flavefaciens and R. albus increased at 24 h, but the relative abundance of F. succinogenes decreased at this time. The incubation of SPs had no effect on the abundance of S. bovis and R. amylophilus. The relative abundance of B. fibrisolvens and S. amylolytica reached the greatest value(p<0.05) at middle doses of SPs inclusion at 24 h. The value of MCPs linearly increased(p<0.05) at 24 and 48 h. These results showed that SPs could improve in vitro fermentation and nutrient digestion of feed substrates, and had the ability to modulate the ruminal fermentation pattern by regulating the composition of functional rumen microbes. Hence, SPs might be a potential feed additive applied in the diets of ruminants.
基金Project (No. 29890282) supported by the National Natural Science Foundation of China.
文摘Pure culture and pot culture experiments were carried out to study the effect of lanthanum (La) on bacteria, actinomyces and fungus, and some microbial physiological groups , nitrifier, azotobacter and phos- phobacteria, in a red soil taken form the Ecological Experimental Station of Red Soil, the Chinese Academy of Sciences, Jiangxi Province. LaCl3 was added into media at levels of 0, 25, 50, 100, 150, 200, 250 and 500 mg L-1 in the pure culture experiment, and into soil samples in porcelain pots before rice growing at levels of 0, 6, 30, 150, 300, 600 and 900 mg kg-1 dry soil in the pot culture experiment. The populations of the three soil microbes in the pure culture experiment decreased with the addition level of La, indicating that La was toxic to the soil microbes in pure culture, and the sensitivity of the 3 major microbial types to La was in a decreasing order of actinomyces > bacteria > fungus. In the pot experiment, La had slightly stimulative effect on soil bacteria and actinomyces when applied at low concentrations while had inhibitory effect on soil bacteria, actinomyces and fungus at high concentrations. When the concentration of La was low, soil azotobacter was stimulated slightly while soil nitrifier was stimulated strongly and the maximum increase was up to 50%. When the concentration of La was high, both soil azotobacter and nitrifier were inhibited, and the inhibition of La to the nitrifier increased with La concentration. La added at all the levels had stimulative effect on soil inorganic and organic phosphobatteria. Among the 4 physiological groups, soil nitrifier was most sensitive to La, so , it might be reasonable to assume that soil nitrifier was a sensitive indicator for evaluating the biological and environmental effects of rare earths.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment (No.2010ZX07319-001-03)the National Natural Science Foundation of China (No.51221892)
文摘The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cubes（PUFC）, on which thermophilic desulfurization bacteria were attached. The thermophilic biofilter effectively reduced SO2 within 10 months of operation time, with a maximum elimination capacity of 48.29 g/m^3/hr.Temporal shifts in the microbial population in the thermophilic biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and deoxyribonucleic acid（DNA） sequence analysis. The substrate species and environmental conditions in the biofilter influenced the microbial population. Oxygen distribution in the PUFC was analyzed using a microelectrode. When the water-containing rate in PUFC was over 98%, the oxygen distribution presented aerobic–anoxic–aerobic states along the test route on the PUFC. The appearance of sulfate-reducing bacteria was caused by the anaerobic conditions and sulfate formation after 4 months of operation.
文摘The experiment was conducted using a total of 1392 one-day-old, Cobb commercial male broilers to investigate the effects of a commercial probiotic addition in diet on growth, the development of the small intestine and microbial populations of broilers. Broilers were randomly allotted by BW to 1 of 6 replicate cages （29 chicks per cage） for each of 8 treatments in a randomized block design involving one factorial arrangement of treatments. Dietary treatments included the basal diet （including corn, soybean, rapeseed, cottonseed meal） added with 100 mg/kg antibiotic, 0%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%. The experiment last 42 d and divided into the starter period （1-21 d） and the finisher period （22-42 d）. The results showed that there were significant differences in broiler body weight （BW） （P〈0.001）, average daily feed intake （ADFI） （P=0.033）, relative length of the duodenum （P〈0.001）, jejunum （P=0.008）, ileum （P〈0.001） and the populations of lactobacillus （P〈0.001） and coliform （P〈0.001） in the rectum between the probiotics treatments and the control treatment only in the starter period of the trails. No significant differences were observed in intestinal morphology parameters in two periods of the experiment. Our results indicated that the probiotic was able to improve the performance of broiler chickens, and it was better in the starter period to be used than in the finisher period.
文摘The objective of the present study was to evaluate the effect of feeding different levels of whole linseed,as a source of n-3 polyunsaturated fatty acids(PUFA), on ruminal fatty acid composition and microbial population in the goat. Twenty-four crossbred Boer goats were assigned to 3 dietary treatments: LO(control), L10 and L20 containing 0,10%, or 20% whole linseed, respectively. The ruminal pH and concentration of total volatile fatty acids(VFA) were not affected by dietary treatments. The feeding of L10 and L20 diets produced higher(P < 0.05) molar proportions of acetate and lower(P < 0.05) molar proportions of butyrate and valerate than the LO diet. Molar proportions of myristic acid(C14:0) and palmitic acid(C16:0) were lower(P < 0.05) in the rumen of goats offered L10 and L20 diets than the control diet. However, stearic acid(C18:0), vaccenic acid(C18:1 trans-11), conjugated linoleic acid(CLA,C18:2 trans-10, cis-12) and a-lenolenic acid(C18:3 n-3) were higher(P < 0.05) in the rumen of goats fed L10 and L20 than L0. Both inclusion levels of linseed in the diet(L10 and L20) reduced the ruminal total bacteria, methanogens, and protozoa compared with LO(P < 0.05). The effect of the dietary treatments on cellulolytic bacteria, varied between the individual species. Both inclusion levels of linseed resulted in a significant decrease(P < 0.05) in the population of Fibrobacter succinogenes, and Rumunococus flavefaciens compared with LO, with no significant difference between the groups fed linseed diets. The population of Rumunococus albus was not affected by the different dietary treatments. It was concluded that inclusion of whole linseed in the diet of goats could increase the concentration of PUFA in the rumen, and decrease the population of F. succinogenes, R. flavefaciens, methanogens and protozoa in rumen liquid of goats.
基金Financial support of the UGC-DAE, Center for Scientific Research, Kolkata Centre
文摘Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed high concentrations of heavy metals in the order of Cr〉Fe〉Zn〉Ni〉Co〉Mn while ground water did not show any heavy metal contamination except Fe. Physico-chemical parameters of mine water samples showed deviation from those of normal water. Mine water harboured low microbial populations of bacteria, fungi and actinomycetes in comparison with mine adjacent water samples. The correlation of data between metals with physico-chemical parameters showed both positive and negative responses while that of metal and microbial population exhibited negative correlation. Bacterial strains isolated from chromite mine water exhibited high tolerance towards chromium and other heavy metals as well as antibiotics which could be used as an indicator of heavy metal pollution.
基金Supported by the Suranaree University of Technology and the Higher Education Research Promotionthe National Research University Project of Thailand,Office of the Higher Education Commission
文摘Plant growth-promoting rhizobacteria （PGPR） have been widely recognized as an important agent, especially as a biofertilizer, in agricultural systems. The objectives of this study were to select effective PGPR for Chinese kale （Brassica oleracea var. alboglabra） cultivation and to investigate the effect of their inoculation on indigenous microbial community structure. The Bacillus sp. SUT1 and Pseudomonas sp. SUT19 were selected for determining the efficiency in promoting Chinese kale growth in both pot and field experiments. In the field experiment, PGPR amended with compost gave the highest yields among all treatments. The Chinese kale growth promotion may be directly affected by PGPR inoculation. The changes of microbial community structure in the rhizosphere of Chinese kale following PGPR inoculation were examined by denaturing gradient gel electrophoresis （DGGE） and principal coordinate analysis. The DGGE fingerprints of 16S rDNA amplified from total community DNA in the rhizosphere confirmed that our isolates were established in the rhizosphere throughout this study. The microbial community structures were slightly different among all the treatments, and the major changes depended on stages of plant growth. DNA sequencing of excised DGGE bands showed that the dominant species in microbial community structure in the rhizosphere were not mainly interfered by PGPR, but strongly influenced by plant development. The microbial diversity as revealed by diversity indices was not different between the PGPR-inoculated and uninoculated treatments. In addition, the rhizosphere soil had more influence on eubacterial diversity, whereas it did not affect archaebacterial and fungal diversities.
基金financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No.2010ZX07319-001-03)the National Natural Science Foundation of China(No.51221892)
文摘The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O_2 and H_2O. In present study, a microelectrode was applied to analyze O_2 in polyurethane foam cubes（PUFCs） packed in a biofilter for SO_2 removal. The O_2 distribution varied with the density and water-containing rate（WCR） of PUFCs. The O_2 concentration dropped sharply from 10.2 to 0.8 mg/L from the surface to the center of a PUFC with 97.20%of WCR. The PUFCs with high WCR presented aerobic–anoxic–aerobic areas.Three-dimensional simulated images demonstrated that the structure of PUFCs with high WCR consisted of an aerobic ＂shell＂ and an anoxic ＂core＂, with high-density PUFCs featuring a larger anoxic area than low-density PUFCs. Moreover, the H_2O distribution in the PUFC was uneven and affected the O_2 concentration. Whereas aerobic bacteria were observed in the PUFC surface, facultative anaerobic microorganisms were found at the PUFC core, where the O_2 concentration was relatively low. O_2 and H_2O distributions differed in the PUFCs, and the distribution of microorganisms varied accordingly.
基金L.D.acknowledges support from the Shenzhen Medical Research Fund(B2302036)the National Key R&D Program of China(2019YFA0906700)+3 种基金the Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines(ZDSYS20210623091810032)L.W.acknowledges support from the National Natural Science Foundation of China(32100089)W.L.Z.acknowledges support from the National Natural Science Foundation of China(32471555)the Shenzhen Medical Research Fund(A2403027).
文摘Recent advancements in single-cell genomic and transcriptomic sequencing,in situ sequencing,and molecular imaging-based technologies have facilitated the examination of heterogeneity within microbial communities at the single-cell level.These cutting-edge methodologies permit the capture of phenotypic and genotypic heterogeneity,as well as the spatial organization within microbial communities.This enables in-depth investigation into microbial dark matter,the evaluation of microbial responses to perturbations,and a comprehensive exploration of spatial functions involved in community assembly and social interactions within microbial communities.These interactions include inter-microbial relationships,bacteria-phage interactions,and host-microbe interactions.Here,we highlight the key technological breakthroughs achieved,elucidating the perspectives from which these technologies enable us to interpret microbial heterogeneity at the single-cell level.Additionally,we critically examine the limitations associated with these technologies.Furthermore,we explore how these methods could be combined and also their applications in future studies.The integration of these approaches holds great promise for increasing our understanding of the organization and function of microbes in complex ecosystems.
基金The first author would like to acknowledge the PostGraduate Contingency Grant received from Bihar Agricultural University,India。
文摘Soil ecosystem is experiencing stresses due to climate change,and soil inhabitants try to demonstrate their inherent resistance and resilience against those stresses.Application of nanomaterials as agricultural inputs could bring shifts in resistance and resilience patterns of soil microbes and associated enzymes,especially under short-term heat stress.With this background,the impacts of multi-walled carbon nanotube(MWCNT)on the resistance and resilience of soil biological indicators were evaluated.An incubation experiment was conducted with varied MWCNT concentrations(0,50,100,250,and 500 mg kg-1soil)for 90 d after 24-h heat stress at 48±2?C to assess the impacts of MWCNT on soil enzyme activities and microbial populations vis-à-vis their resistance and resilience indices under short-term exposure to heat stress.Enzyme activities were reduced after exposure to heat stress.Resistance indices of enzyme activities were enhanced by MWCNT application on day 1 after heat stress,whereas there was no recovery of enzyme activities after 90-d incubation.Like soil enzyme activities,resistance index values of soil microbial populations followed the similar trend and were improved by MWCNT application.Multi-walled carbon nanotube has the potential to improve resistance indices of soil enzyme activities and microbial populations under heat stress,although they could not recover to their original state during periodical incubation after heat stress.This study helps to understand the relative changes of biological indicators under MWCNT and their ability to withstand heat stress.
基金Supported by National Natural Science Foundation of China (30900196)Doctoral Scientific Research Fund of Three Gorges University (0620070132)~~
文摘[Objective] The paper was to study the bioactive characteristics of soil microorganisms in different-aged orange plantations. [Method] Taking 010 cm deep soil in 3 orange plantations with different planting years in suburb of Yichang City as the test object, the variation rule of total organic carbon, total nitrogen, soil pH value, microbial biomass carbon, microbial biomass nitrogen, number of 3 main types of soil microbial flora, basal respiration, microbial entropy and metabolic entropy in differentaged orange plantations was studied. [Result] With the increase of planting years, the soil acidification of different-aged orange plantations was aggravating; total organic carbon and total nitrogen content increased first and then decreased; the total number of soil microorganism showed a downtrend, of which the number of bacteria decreased significantly, the number of actinomycetes had small changes, the number of fungi increased significantly, and the ratio of bacteria and fungi in soil （B/F） showed a decreasing trend. Soil microbial biomass carbon was fluctuated within a small range, whereas soil microbial biomass nitrogen decreased significantly; soil microbial entropy decreased significantly, and metabolic entropy showed an increasing trend. This indicated that the decrease of soil pH value affected the changes of soil microbial flora, microbial activity, microbial biomass carbon and nitrogen and soil major nutrients, and further affected the normal exertion of soil function. [Conclusion] The study explores soil nutrient characteristics and changes of microbial flora in test area, which will provide scientific basis for further study on orchard soil and orchard management.
文摘Different kinds of mineral nutrients(NO_3-N, NH_4-N and PO_4-P) were applied in the simulated oil-polluted seawater for enhancing oil biodegradation in the N/P ratio 10∶1 and 20:1 Although indigenous microorganisms have the ability to degrade oil, adding nutrients accelerated biodegradation rates significantly. For the group amended with NO_3-N and PO_4-P in the ratio 10∶1, the reaction rate coefficient was 4 times higher than the natural biodegradation. Chemical and microbiological analysis showed that the optimal N/P ratio in the system is 10∶1, and microorganisms tend to utilize nitrate rather than ammonium as N source.
