Variations of phyllosphere microorganisms in asymptomatic and tobacco brown spot leaves before and after spraying 12% difenoconazole + fluxapyroxad SC

12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,etc.This study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing technology.The results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of A.alternata.Both asymptomatic and symptomatic leaves presented complex microbial communities.Higher fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic leaves.After application,the diversity and abundance of microbial community structures in both types of leaves changed over time.Fungal microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic leaves.Fungal community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of application.Meanwhile,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 days.The abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of Jiangong.However,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-plant pathogen,plant pathogen-undefined saprotroph)was significantly affected by the application of Jiangong,and high variation was found in symptomatic leaves than that of asymptomatic leaves.The application of Jiangong-induced alterations in the community structure of the tobacco phyllosphere microbiome provides a basis for future tobacco brown spot control strategies based on phyllospheric microecology.

Probiotic microorganisms affect the reproductive and nervous systems of male rats treated with acrylamide

Objective:To evaluate the protective effects of probiotic microorganisms on the reproductive and nervous systems of male rats treated with acrylamide.Methods:Thirty-two rats were randomly divided into 4 groups and received normal saline through gavage(control),acrylamide 20 mg/kg body weight,acrylamide plus probiotic microorganisms(Lactobacillus acidophilus,Lactobacillus casei,Lactobacillus bulgaricus,Lactobacillus rhamnosus,Bifidobacterium breve,Bifidobacterium infantis,Streptococcus thermophilus and fructooligosaccharides,all mixed in sachets)20 or 200 mg/kg body weight,respectively.After 30 days,the testis,prostate,seminal vesicle and cerebellum were removed,fixed and stained with hematoxylin-eosin(H&E).The Johnsen score was used to classify spermatogenesis.Cavalieri's principle method was used to evaluate the total volume(in mm3)of the testes.The number of each intratubular cell type as well as intertubular Leydig cells in whole samples was measured using the physical dissector counting techniques.Stereological analysis and the grids were used to determine the volume of cerebellar layers as well as the Purkinje cell number.Results:The testis weight decreased significantly in the acrylamide-treated group compared to the other groups(P<0.001).The number of spermatogonia,spermatocytes,spermatids and Leydig cells in the acrylamide-treated group were significantly less compared to the control group(P<0.05),while they were increased significantly in the acrylamide+200 mg/kg probiotic group(P<0.05;P<0.01).The mean Johnsen score in the acrylamide-treated group was lower than in the control group(P<0.001).Acrylamide-induced changes including congestion,vacuolization in the secretory epithelial cells,and epithelial rupture were observed in the prostate and seminal vesicle.The volumes of cerebellar layers were decreased in the acrylamide group compared to the control group while recovered in both probiotic treated groups.Conclusions:Probiotic microorganisms alleviate acrylamide-induced toxicities against the reproductive and cerebellar tissues in rats.

Responses of plant diversity and soil microorganism diversity to nitrogen addition in the desert steppe,China

Nitrogen(N)deposition is a significant aspect of global change and poses a threat to terrestrial biodiversity.The impact of plant-soil microbe relationships to N deposition has recently attracted considerable attention.Soil microorganisms have been proven to provide nutrients for specific plant growth,especially in nutrient-poor desert steppe ecosystems.However,the effects of N deposition on plant-soil microbial community interactions in such ecosystems remain poorly understood.To investigate these effects,we conducted a 6-year N-addition field experiment in a Stipa breviflora Griseb.desert steppe in Inner Mongolia Autonomous Region,China.Four N treatment levels(N0,N30,N50,and N100,corresponding to 0,30,50,and 100 kg N/(hm2•a),respectively)were applied to simulate atmospheric N deposition.The results showed that N deposition did not significantly affect the aboveground biomass of desert steppe plants.N deposition did not significantly reduce the alfa-diversity of plant and microbial communities in the desert steppe,and low and mediate N additions(N30 and N50)had a promoting effect on them.The variation pattern of plant Shannon index was consistent with that of the soil bacterial Chao1 index.N deposition significantly affected the beta-diversity of plants and soil bacteria,but did not significantly affect fungal communities.In conclusion,N deposition led to co-evolution between desert steppe plants and soil bacterial communities,while fungal communities exhibited strong stability and did not undergo significant changes.These findings help clarify atmospheric N deposition effects on the ecological health and function of the desert steppe.

Effect of salinization on soil properties and mechanisms beneficial to microorganisms in salinized soil remediation-a review

Salinized soil is an important reserved arable land resource in China.The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield.Salt accumulation will lead to the deterioration of soil properties,destroy soil production potential and damage soil ecological functions,which in turn will threaten global water and soil resources and food security,and affect sustainable socio-economic development.Microorganisms are important components of salinized soil.Microbial remediation is an important research tool in improving salinized soil and is key to realizing sustainable development of agriculture and the ecosystem.Knowledge about the impact of salinization on soil properties and measures using microorganisms in remediation of salinized soil has grown over time.However,the mechanisms governing these impacts and the ecological principles for microbial remediation are scarce.Thus,it is imperative to summarize the effects of salinization on soil physical,chemical,and microbial properties,and then review the related mechanisms of halophilic and halotolerant microorganisms in salinized soil remediation via direct and indirect pathways.The stability,persistence,and safety of the microbial remediation effect is also highlighted in this review to further promote the application of microbial remediation in salinized soil.The objective of this review is to provide reference and theoretical support for the improvement and utilization of salinized soil.

The Combination of Achnatherum inebrians Extracts and Soil Microorganisms Inhibited Seed Germination and Seedling Growth in Elymus nutans

In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans.

Functions and Applications of Intestinal Symbiotic Microorganisms in Insects

Insects represent a diverse group of organisms on earth that carry a vast array of symbiotic microorganisms in their intestines.These microorganisms have established a complex and intimate symbiotic relationship with their host insects over an extended period of evolutionary adaptation.The population structure of intestinal symbiotic microorganisms in insects exhibits a high degree of diversity,with notable differences among insect species.Conversely,within the same insect species,the population structure of symbiotic microorganisms in specific intestinal sites demonstrates a certain degree of stability and specificity.These symbiotic microorganisms perform various physiological functions in the host insect.Their biological functions encompass nutrient and material metabolism and immune and protective mechanisms,which have significant effects on host insect longevity,development,and reproductive capacity.These microorganisms have diverse applications,including pest control,bioenergy production,the development of insect resources,etc.Recent advancements in high-throughput sequencing technology have revealed a growing diversity and biological properties of these microorganisms.The application of these techniques has significantly contributed to the advancement of research in the field of insect intestinal microbial research,providing researchers with powerful tools for a deeper understanding and utilization of these symbiotic microorganisms.This study reviewed the research progress of insect intestinal microorganisms in three aspects:diversity,biological functions,and applications.The objective was to provide useful references and insights for further research and applications of insect intestinal microorganisms.

Bibliometric analysis of soil phosphate solubilizing microorganisms research using VOSviewer

Phosphorus-solubilizing microbes play key roles in improving phosphorus availability and in alleviating phosphorus nutrient limitation in soils. However, we did not have a comprehensive understanding of the overall research progress and development trend of phosphorus solubilizing microorganisms. In this study, we obtain documents from the Web of Science (WOS) core collection between 2002 and 2022, and a comprehensive review of the progress of global research on soil phosphate solubilizing microorganisms was conducted by using the VOSviewer bibliometric analysis tool. The results showed an increasing trend in the number of published articles from 2002 to 2022. India, accounting for 28% of the total number of published articles, became the most productive country. However, Canada was the country with the highest average citation frequency of articles. Chinese Academy of Sciences (CAS) was the greatest contributor with the most publications. Among the published journals, Frontiers in Microbiology, Applied Soil Ecology and Plant and Soil were the top three core journals in this field. Based on the keyword analysis, the assessment of the mechanisms between phosphorus solubilizing microbes and the soil carbon cycles with the different management practices became the new research trend among the scientific communities. These findings would provide an important reference value for future in-depth research on soil phosphate solubilizing microorganisms.

Identification of Microorganisms in Poultry Farms in N’djamena and the Border Areas of Hadjer-Lamis and Chari-Baguirmi Chad

Introduction: On the outskirts of Ndjamena, semi-industrial poultry farming and traditional poultry farming are practised informally on almost all poultry farms in Chad. This type of poultry farming is faced with real health problems attributable to a lack of monitoring of the vaccination schedule, inadequate compliance with biosecurity measures and poor application of the Ichikawa rule based on the 5 M’s. Objective: The aim of this article is to identify the microorganisms responsible for contamination of poultry farms in the study area. Method: The study was carried out from 28/04/2022 to 31/01/2023 on the basis of 300 samples taken from feed, drinking water, droppings and scrapings from poultry housing surfaces in the 30 farms that served as a framework for our research. Sampling was of the simple random type, and farms were selected on the basis of the farmers’ consent. The data were recorded on pre-established survey forms. Our study was cross-sectional, descriptive and prospective. Bacteria were isolated using the reference method NF EN ISO 6579 for Salmonella spp. and cultured on the specific medium eosin methylene blue (EMB) for Escherichia coli, Pseudomonas and Citrobacter freundii. Results: The following results emerged from this study: Escherichia coli (5.33%), Pseudomonas (1.33%), Citrobacter freundii (12%) and Salmonella paratyphi (21.68%). Conclusion: Of the 300 samples analysed, 121 (40.33%) were contaminated with pathogens. This high level of contamination is a health problem. The study shows that biosecurity is less satisfactory on the farms visited. Nevertheless, farms with a very satisfactory level of biosafety ensure food safety and variety for the population.

Influence of Microorganisms Effective against Basal Rot and on Agronomic Parameters of Onion [Allium cepa L. (Amaryllidaceae)]

Onions are a horticultural crop of great economic, dietary and medicinal importance, and are highly prized by the Ivorian population. However, production remains low, due to a number of constraints, including parasitic attacks. The most frequent is fusariosis caused by Fusarium sp., a pathogen that causes enormous damage to onion crops. Faced with these attacks, chemical control appears to be ineffective, with consequences for human health and the environment. This is why the search for effective alternative methods that respect the environment and human health is so necessary. It is in this context that this study was carried out, with the general aim of controlling fusarium wilt in onion crops, with a view to improving onion production in Ivory Coast through the use of effective microorganisms. The experimental set-up used for this purpose was a fisher block with complete randomization, comprising three replicates. A fungal spore concentration of 106 spore/mL of Fusarium sp., three doses (1%;2.5% and 5% v/v) of EM and one dose of a chemical fungicide (30 mL/16L) were tested on young onion plants. Each block consisted of nine sub-plots with nine treatments. Health parameters (incidence and severity) and agronomic parameters (growth and yield) were assessed. Microbiological analysis of the EM revealed the presence of nine morphotypes of Trichoderma sp., Aspergillus clavatus, Aspergillus flavus, Aspergillus sp., Penicillium sp., Rhizopus sp., lactic acid bacteria of the Bacillus family and the yeast Saccharomyces cerevisiae. Field experimentation showed that the 5% EM microbial solution reduced the incidence and severity of fusariosis compared with the chemical fungicide, and proved to be the best. This dose reduced yield losses by 7.14%, while improving onion growth and yield by over 5%. The results demonstrated the ability of the EM solution to effectively control the causal agent of basal rot in onion crops.

Causative Microorganisms Isolated from Patients with Intra-Abdominal Infections and Their Drug Resistance Profiles:An 11-Year(2011–2021)Single-Center Retrospective Study

Objective To investigate the distribution and antimicrobial susceptibility of causative microorganisms recovered from patients with intra-abdominal infections(IAIs).Methods A total of 2,926 bacterial and fungal strains were identified in samples collected from 1,679 patients with IAIs at the Peking Union Medical College Hospital between 2011 and 2021.Pathogenic bacteria and fungi were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.Antimicrobial susceptibility testing(AST)was performed using the VITEK 2 compact system and the Kirby–Bauer method.AST results were interpreted based on the M100-Ed31 clinical breakpoints of the Clinical and Laboratory Standards Institute.Results Of the 2,926 strains identified,49.2%,40.8%,and 9.5%were gram-negative bacteria,gram-positive bacteria,and fungi,respectively.Escherichia coli was the most prevalent pathogen in intensive care unit(ICU)and non-ICU patients;however,a significant decrease was observed in the isolation of E.coli between 2011 and 2021.Specifically,significant decreases were observed between 2011 and 2021 in the levels of extended-spectrumβ-lactamase(ESBL)-producing E.coli(from 76.9%to 14.3%)and Klebsiella pneumoniae(from 45.8%to 4.8%).Polymicrobial infections,particularly those involving co-infection with gram-positive and gram-negative bacteria,were commonly observed in IAI patients.Moreover,Candida albicans was more commonly isolated from hospital-associated IAI samples,while Staphylococcus epidermidis had a higher ratio in community-associated IAIs.Additionally,AST results revealed that most antimicrobial agents performed better in non-ESBL-producers than in ESBL-producers,while the overall resistance rates(56.9%–76.8%)of Acinetobacter baumanmii were higher against all antimicrobial agents than those of other common gram-negative bacteria.Indeed,Enterococcus faecium,Enterococcus faecalis,S.epidermidis,and S.aureus were consistently found to be susceptible to vancomycin,teicoplanin,and linezolid.Similarly,C.albicans exhibited high susceptibility to all the tested antifungal drugs.Conclusion The distribution and antimicrobial susceptibility of the causative microorganisms from patients with IAls were altered between 2011 and 2021.This finding is valuable for the implementation of evidence-based antimicrobial therapy and provides guidance for the control of hospital infections.

Impact of microorganism degradation on hydrocarbon generation of source rocks:A case study of the Bozhong Sag,Bohai Bay Basin

The discovery of the Bozhong 19-6 gas field,the largest integrated condensate gas field in the eastern China in 2018,opened up a new field for the natural gas exploration deep strata in the Bohai Bay Basin,demonstrating there is a great potential for natural gas exploration in oil-type basins.The ethane isotope of the Bozhong 19-6 condensate gas is heavy,showing the characteristics of partial humic gas.In this paper,aimed at the source rocks of the Bozhong 19-6 gas field in the Bohai Bay Basin,the characteristics of the source rocks in the Bozhong 19-6 structural belt were clarified and the reason are explained from impact of microorganism degradation on hydrocarbon generation of source rocks why the condensate oil and gas had heavy carbon isotope and why it showed partial humic characteristics was explored based on the research of parent materials.The following conclusions were obtained:The paleontology of the Bozhong 19-6 structural belt and its surrounding sub-sags is dominated by higher plants,such as angiosperm and gymnosperm.During the formation of source rocks,under the intensive transformation of microorganism,the original sedimentary organic matter such as higher plants was degraded and transformed by defunctionalization.Especially,the transformation of anaerobic microorganisms on source rocks causes the degradation and defunctionalization of a large number of humic products such as higher plants and the increase of hydrogen content.The degradation and transformation of microorganism don't transform the terrestrial humic organic matter into newly formed“sapropel”hydrocarbons,the source rocks are mixed partial humic source rocks.As a result,hydrogen content incrased and the quality of source rocks was improved,forming the partial humic source rocks dominated by humic amorphous bodies.The partial humic source rocks are the main source rocks in the Bozhong 19-6 gas field,and it is also the internal reason why the isotope of natural gas is heavy.

Shape Effect of Nanoparticles on Nanofluid Flow Containing Gyrotactic Microorganisms

In this paper,we discussed the effect of nanoparticles shape on bioconvection nanofluid flow over the vertical cone in a permeable medium.The nanofluid contains water,Al2O3 nanoparticles with sphere(spherical)and lamina(non-spherical)shapes and motile microorganisms.The phenomena of heat absorption/generation,Joule heating and thermal radiation with chemical reactions have been incorporated.The similarity transformations technique is used to transform a governing system of partial differential equations into ordinary differential equations.The numerical bvp4c MATLAB program is used to find the solution of ordinary differential equations.The interesting aspects of pertinent parameters on mass transfer,energy,concentration,and density of themotilemicroorganisms’profiles are computed and discussed.Our analysis depicts that the performance of sphere shape nanoparticles in the form of velocity distribution,temperature distribution,skin friction,Sherwood number and Motile density number is better than lamina(non-spherical)shapes nanoparticles.

Revisiting “Non-Thermal” Batch Microwave Oven Inactivation of Microorganisms

Over the last few decades there has been active discussion concerning the mechanisms involved in “non-thermal” microwave-assisted inactivation of microorganisms. This work presents a novel non-invasive acoustic measurement of a domestic microwave oven cavity-magnetron operating at fo = 2.45 ± 0.05 GHz (λo ~ 12.2 cm) that is modulated in the time-domain (0 to 2 minutes). The measurements reveal the cavity-magnetron cathode filament cold-start warm-up period and the pulse width modulation periods (time-on time-off and base-time period, where time-on minus base-time = duty cycle). The waveform information is used to reconstruct historical microwave “non-thermal” homogeneous microorganism inactivation experiments: where tap-water is used to mimic the microorganism suspension;and ice, crushed ice, and ice slurry mixture are used as the cooling media. The experiments are described using text, diagrams, and photographs. Four key experimental parameters are indentified that influence the suspension time-dependent temperature profile. First, where the selected process time > the time-base, the cavity-magnetron continuous wave rated power should be used for each second of microwave illumination. Second, external crushed ice and ice slurry baths induce different cooling profiles due to difference in their heat absorption rates. In addition external baths may shield the suspension resulting in a retarding of the time-dependent heating profile. Third, internal cooling systems dictate that the suspension is directly exposed to microwave illumination due to the absence of surrounding ice volume. Fourth, four separated water dummy-loads isolate and control thermal heat transfer (conduction) to and from the suspension, thereby diverting a portion of the microwave power away from the suspension. Energy phase-space projections were used to compare the “non-thermal” energy densities of 0.03 to 0.1 kJ·m-1 at 800 W with reported thermal microwave-assisted microorganism inactivation energy densities of 0.5 to 5 kJ·m-1 at 1050 ± 50 W. Estimations of the “non-thermal” microwave-assisted root mean square of the electric field strength are found to be in the range of 22 to 41.2 V·m-1 for 800 W.

Bioturbation Effects of Benthic Fish on Soil Microorganism of Paddy Field

[Objective]The research aimed to explore the bioturbation effects of benthic fish Misgurnus anguillicaudatus on soil microorganism（microflora,biomass,and special physiological groups） of paddy field.[Method]The experiments were conducted locally and quantitatively in field,using plate count and MPN methods.[Result]In the microflora of paddy soil tested,the quantity of bacteria is the largest,followed by actinomycetes and fungus.Compared with the control paddy fields,in rice-fish paddy fields the quantities of bacteria,actinomycetes and fungus were higher,at significance level P 〈0.05,P 〈0.01,and P 〈0.01 respectively.The microbial biomass C and N in rice-fish paddy fields is remarkably higher than those in control paddy fields,both at significance level P 〈0.01;the microbial biomass P in rice-fish paddy fields is higher than that in control paddy fields,but at significance level P 〈0.05.Benthic fish promotes the growth of soil azotobacter,cellulolytic bacteria,nitrobacteria,sulfur bacteria,and ammonifying bacteria,restricts the reproduction of nitrate reducing bacteria and sulfate reducing bacteria.[Conclusion]The benthic fish had important effects on microflora,microbial biomass,and special microorganism physiological groups of paddy soil,improves the living conditions of soil microorganisms,promotes the soil fertility and bio-chemical activity,which is beneficial for improving the supply ability of soil nutrients such as N,P,S,as well as the efficiency of nutrient utilization.

Effects of Cr^(6+) Stress Culture on Rhizosphere Microorganism of Aquatic Plants

Using traditional microbiological culture method,under laboratory conditions,different concentrations of Cr6＋ were selected for stress culture on Pistia stratiote,Sagittaria sagittifolia and Myriophyllum spicatum.Through determination of the rhizosphere microorganism and the nitrogen cycle bacteria change of three kinds of aquatic macrophytes,the tolerance of rhizosphere microorganism to Cr6＋ was studied.The results showed that the sensitivity of microorganisms could be summarized as：actinomycete bacteria fungi,it has no obvious regularity about tolerance of 3 microorganisms;while the effects demonstrated their specificity on ammonification bacteria,nitrifying bacteria,nitrosococcus bacteria and denitrifying bacteria.

Biological Characteristics and Rumen Microorganisms of Gayal(Bos frontalis)in Yunnan Province

[Objective]The paper was to provide reference for further study and development of gayal（Bos frontalis）.[Method]According to the research status at home and abroad,the biological characteristics and rumen microorganisms of gayal in Yunnan Province was studied.[Result]Gayal in Yunnan had typical body form and very good meat production performance,its muscle fiber diameter was significantly less than other kinds of cattle;the water holding ratio,muscle tenderness and muscle succulency were significantly higher than others;its amount,shape and structure of chromosome were different from yellow cattle（Bos taurus）and wild cattle（Bos gaurus）,and the amounts of those chromosomes（2n）were 58,60 and 56,respectively.It could create hybrid with yellow cattle;the gayal＇s special diet was bamboo,its in vitro dry matter digestibility（IVDMD）on various crude forage was significantly higher than yellow cattle in Yunnan;the viable bacteria and cellulolytic bacteria in rumen were 4.51×109 and 1.63×109 CFU/ml,which was significantly higher than yellow cattle in Yunnan,its dominant bacteria in rumen mainly was cellulolytic bacteria.[Conclusion]Gayal not only had high academic value,but also had a great development value.

Function of microorganism and reaction pathway for carrollite dissolution during bioleaching

The function of microorganism and dissolution reaction pathway of carrollite in the bioleaching process were investigated. The results showed that both indirect and contact mechanisms influenced the leaching process. The dissolution of carrollite was significantly accelerated when bacteria were adsorbed on the mineral surface, indicating that the contact mechanism significantly affected the dissolution of carrollite. During bioleaching, the sequence of oxidation state of the sulfur moiety of carrollite was as follows： S？2→S0→S＋4→S＋6. Elemental sulfur precipitated on the mineral surface, indicating that the dissolution of carrollite occurred via the polysulfide pathway. The surface of carrollite was selectively corroded by bacteria, and oxidation pits with different sizes were observed at various sites. Elemental sulfur, sulfate and sulfite were present on the surface of carrollite during the leaching process, and may have formed a passivation layer on mineral surface.

Impact of Transgenic Bt+CpTI Cotton on Soil Enzyme Activities and Soil Microorganisms

Due to its strong and effective insecticidal properties, transgenic Bt＋CpTI cotton has witnessed an expanding planting area in recent years, and the impact of its cultivation on soil ecosystem becomes an important part of environmental risk assessment. Using transgenic Bt＋CpTI cotton sGK321 and its parental homologous conventional cotton Shiyuan 321 as the study objects, a comparative analysis was conducted on the changes in enzyme activities （urease, alkaline phosphatase, and catalase） of the rhizosphere soil and changes in the number of culturable microor-ganisms （bacteria, fungi, and actinomycetes） at different growth stages （seedling stage, budding stage, flower and bol stage, and bol opening stage） of sGK321 and Shiyuan 321 under the condition of 13 years field plantings. The results showed that, the populations of bacteria, fungi, and actinomycete and the soil enzyme activi-ties of urease, alkaline phosphatase and catalase had a similar variation trend along with the cotton growing process for transgenic cotton and conventional cotton. Some occasional and inconsistent effects on soil enzyme activities and soil fungi composi-tion in the rhizosphere soil of transgenic Bt＋CpTI cotton were found at the seedling stage, budding stage, flower and bol stage as compared with that of conventional cotton. The amount of bacteria and actinomycetes were not significantly different during a certain stage; however, the activities of urease, catalase, alkaline phos-phatase, also with the number of fungi were significantly different, e.g. the urease activities at seedling stage, the alkaline phosphatase at seedling and budding stages, and the soil culturable fungi at flower and bol stage were less than that of conven-tional cotton, while the soil alkaline phosphatase activities at flower and bol stage were higher. Cluster analysis showed that soil enzyme activities and microbial popu-lation changed mainly along the growth processes, suffering little from the planting of transgenic Bt＋CpTI cotton.

Composition of the Microorganism Community Found in the Soil Cover on the Dried Seabed of the Aral Sea

As a result of the Aral Sea shrinkage, the unique freshwater body has given place to a huge bitter-saline lake with an area 3.5 times less, volume 6 times less and water salinity 10 times larger than in 1960, and the saline desert at the interface between three sand deserts with an area of more than 5 million ha, being unstable ecological zone. The exposed ground is illustrative of arid salt-accumulation, where was created specific type of soil-costal solonchak. The origination of life in the soil of the dried bed starts long before the occurrence of external characteristics. This process can be traced only by studying the microbiological composition of soil. Research in this direction, was conducted in order to determine the microbiological composition of soil for horizons of one typical profile of solonchak. The research objective was to determine microorganism species in the soil on the dried seabed, identify changes in the microorganism community along the soil profile and dependence on duration of the drying process. Additionally, we paid attention to a vegetation effect on the composition of microorganisms. Soil samples were taken along a transect from the sea to the mainland, selected from the different depth of soil profiles taken under or near plant (saxaul). The method Gas chromatography mass-spectrometry was used. Bacteria of the community of microorganisms in different parts of the soil cover on the dried seabed of the Aral Sea and on the mainland belong to five bacterial phyla: Proteobacteria Actinobacteria Firmicutes Bacteroidetes and Deinococcus-Thermus. In general, 59 bacterial species of 43 genera were reconstructed. The total population varied from 105 cells/g to 108 cells/g of the soil. The association Aeromonas hydrophila-Arthrobacter sp. played the key role at the first stages of the soil formation process on the dried seabed of the Aral Sea. This association is followed by salt-resistant Agrobacterium sp. and humus-accumulating Propionibacterium freudenreichii, activity of which is also very important for the formation of the soil cover. The studying properties of the dried seabed cover of both salt composition and microbiological composition made it possible to trace the formation of primary soil on marine sediments with the subsequent formation of desert-type soil.

Influences of Oyster Shell Soil Conditioner on Soil and Plant Rhizospheric Microorganisms

Oyster shell soil conditioner had significant influence on soil and rhizospheric microorganisms in their biomass,respiratory intensity and nutritional requirement. It could stimulate growth of soil and rhizospheric microorganisms, especially nitrogen-fixers, and intensify soil respiration in proportion to the dose and fertilizing time of the conditioner, leading to the increase in the number of nitrogen fixing bacteria and the decrease in the number of bacteria with special nutrition demands.