Hydrocarbon bioremediation potential of an unimpacted Kuwaiti oil-field environment

Seasonal variations in the hydrocarbon-degrading potential of soil samples from an unimpacted site in the Kuwaiti Burgan oil field environment were studied under mesophilic conditions. Hydrocarbon-degrading microorganisms occurred but varied all-year-round, and their numbers ranged from 1.3 x 10(7) to 9.3 x 10(7) CFU g(-1) dry soil, while hydrocarbon-degrading fungi ranged from 3.0 x 10(4) - 3.8 x 10(5) CFU g(-1) dry soil, depending on the sampling period. These hydrocarbon-degraders also comprised variable but generally high proportions of the total aerobic heterotrophic organisms (2 to > 98%) for bacteria and lower levels (7-9%) for fungi. The crude oil-degrading capacity of the oil-degrading populations (bacteria and fungi) ranged from 80-95% of the hexane-extractable fractions. Differential inhibition studies carried out on soil samples showed that bacteria were the greater contributors to hydrocarbon degradation (79-92%) than fungi. Pure hydrocarbon substrates, hexadecane and phenanthrene, were degraded to near completion after a 28-day incubation by both the bacterial and fungal portions of the soil flora.     

医院病房环境真菌监测分析

目的 调查医院各病区环境中真菌含量及分布特点.方法 运用分离培养及DNA测序方法对医院不同病区、不同环境中真菌进行监测分析.结果 医院不同病区真菌含量不同,呼吸科、血液科、小儿科空气中真菌含量较高,分别为400、225和200 CFU/m3,其中以烟曲霉菌( 325 CFU/m3)、黄曲霉菌( 275 CFU/m3)、枝孢霉菌( 125 CFU/m3)、根霉( 125 CFU/m3)为主;老年病科、肿瘤科和血液科空调出气口真菌含量较高,分别为0.559、0.500和0.323 CFU/cm2,以链格孢霉(0.441 CFU/cm2)、根霉(0.412 CFU/cm2)、烟曲霉菌(0.294 CFU/cm2)为主;不同环境中真菌含量不同,其中以空气和空调出气口真菌含量最高,分别为130 CFU/m3、0.173 CFU/cm2.结论 真菌广泛存在于医院环境中,且不同病区、不同环境真菌污染程度不同,因而我们必须制订健全的消毒管理制度,预防医院真菌感染.     

Characterization and Control of the Microbial Community Affiliated with Copper or Aluminum Heat Exchangers of HVAC Systems

Microbial growth in heating ventilation and air-conditioning (HVAC) systems with the subsequent contamination of indoor air is of increasing concern. Microbes and the subsequent biofilms grow easily within heat exchangers. A comparative study where heat exchangers fabricated from antimicrobial copper were evaluated for their ability to limit microbial growth was conducted using a full-scale HVAC system under conditions of normal flow rates using single-pass outside air. Resident bacterial and fungal populations were quantitatively assessed by removing triplicate sets of coupons from each exchanger commencing the fourth week after their installation for the next 30 weeks. The intrinsic biofilm associated with each coupon was extracted and characterized using selective and differential media. The predominant organisms isolated from aluminum exchangers were species of Methylobacterium of which at least three colony morphologies and 11 distinct PFGE patterns we found; of the few bacteria isolated from the copper exchangers, the majority were species of Bacillus. The concentrations and type of bacteria recovered from the control, aluminum, exchangers were found to be dependent on the type of plating media used and were 11,411-47,257 CFU cm(-2) per coupon surface. The concentration of fungi was found to average 378 CFU cm(-2). Significantly lower concentrations of bacteria, 3 CFU cm(-2), and fungi, 1 CFU cm(-2), were recovered from copper exchangers regardless of the plating media used. Commonly used aluminum heat exchangers developed stable, mixed, bacterial/fungal biofilms in excess of 47,000 organisms per cm(2) within 4 weeks of operation, whereas the antimicrobial properties of metallic copper were able to limit the microbial load affiliated with the copper heat exchangers to levels 99.97 % lower during the same time period.     

Characterization of Fungal Biofilms within a Municipal Water Distribution System

Biofilms of a municipal water distribution system were characterized to assess the occurrence of fungi within surface matrixes. Densities of filamentous fungi ranged from 4.0 to 25.2 CFU cm⁻², whereas yeast densities ranged from 0 to 8.9 CFU cm⁻². Observations by scanning electron microscopy further suggested that spores, not hyphae or vegetative cells, comprised the primary source of viable propagules.     

亚高山针叶林土壤动物和土壤微生物对针叶分解的作用（英文）

 通过80片亚高山针叶林土壤有机物层切片的显微观察和统计,并结合微生物（CFU）的培养观察,对亚高山针叶林土壤有机物分解过程中土壤动物和土壤微生物的作用进行了研究。根据可见针叶数目和C/N比率在土壤有机物层的垂直分布变化将分解过程分为3个阶段。真菌数量（CFU）在第一阶段（表层0～2 cm）明显高于第二和第三阶段（深层）;与此相反细菌的数量（CFU）却表层少深层多。具有虫便的针叶在表层（0～2 cm）为最多,而深于2 cm后便急剧减少,至4.5 cm处为零。综合以上结果并结合微形态观察我们认为针叶的分解过程     

Detection and recovery rates achieved using direct plate and enrichment/immunomagnetic separation methods for Escherichia coli O157:H7 in minced beef and on bovine hide

AIMS: To assess the detection and recovery rates achieved with commonly used cultural methods for the enumeration and recovery of Escherichia coli O157:H7 from minced beef and bovine hide. METHODS AND RESULTS: Minced beef and bovine hide were inoculated with varying concentrations (log(10) 1.58-2.58 CFU g(-1) and log(10) 2.42-4.49 CFU 100 cm(2) respectively) of E. coli O157:H7 and recovered using a direct plate method or an enrichment/immunomagnetic separation (IMS) method and then plated onto SMAC or SMAC-CT in both cases. The direct plate method detected the pathogen consistently from minced beef samples with an average recovery of 69.2-91.2%. From faecal material on the bovine hide the recovery of the pathogen ranged from 1.80 to 64.5% with fresh faeces depending on the inocula while from dried faeces on hide the results ranged from no recovery at all to 25.1%. Enrichment/IMS recovered E. coli O157:H7 at all inocula levels tested in minced beef while the pathogen was only detected consistently at an average inocula level of log(10) 2.73 CFU 100 cm(2) from fresh faeces and log(10) 4.49 CFU 100 cm(2) from dried faeces on bovine hide. CONCLUSIONS: The direct count enumeration method for E. coli O157:H7 underestimated the numbers of pathogens present. The enrichment/IMS procedure consistently detected the pathogen from minced beef but did not always detect E. coli O157:H7 from faeces on bovine hide. SIGNIFICANCE AND IMPACT OF THE STUDY: Overall this study highlights that any microbial data, used in either predictive microbiology or risk assessment, must take account of the sensitivity and associated performance of the methods employed, in order to make an accurate reflection of the true microbiology of the examined sample.     

Fungal colonization and biodeterioration of plasticized polyvinyl chloride

Significant substratum damage can occur when plasticized PVC (pPVC) is colonized by microorganisms. We investigated microbial colonization of pPVC in an in situ, longitudinal study. Pieces of pPVC containing the plasticizers dioctyl phthalate and dioctyl adipate (DOA) were exposed to the atmosphere for up to 2 years. Fungal and bacterial populations were quantified, and colonizing fungi were identified by rRNA gene sequencing and morphological characteristics. Aureobasidium pullulans was the principal colonizing fungus, establishing itself on the pPVC between 25 and 40 weeks of exposure. A group of yeasts and yeast-like fungi, including Rhodotorula aurantiaca and Kluyveromyces spp., established themselves on the pPVC much later (after 80 weeks of exposure). Numerically, these organisms dominated A. pullulans after 95 weeks, with a mean viable count +/- standard error of 1,000 +/- 200 yeast CFU cm(-2), compared to 390 +/- 50 A. pullulans CFU cm(-2). No bacterial colonization was observed. We also used in vitro tests to characterize the deteriogenic properties of fungi isolated from the pPVC. All strains of A. pullulans tested could grow with the intact pPVC formulation as the sole source of carbon, degrade the plasticizer DOA, produce extracellular esterase, and cause weight loss of the substratum during growth in vitro. In contrast, several yeast isolates could not grow on pPVC or degrade DOA. These results suggest that microbial succession may occur during the colonization of pPVC and that A. pullulans is critical to the establishment of a microbial community on pPVC.     

Fungal Communities on Rock Surfaces in Demänovská Ice Cave and Demänovská Cave of Liberty (Slovakia)

This paper is the first geomycological report regarding the fungal communities on rock surfaces in the Demänovská Ice Cave and the Demänovská Cave of Liberty, Slovakia. The samples were collected in June 2014 from five locations from inside both the caves by using sterile swabs wetted with physiological saline (0.85% NaCl). The density of epilithic fungi isolated from the Demänovská Ice Cave ranged from 238.7 to 575.1 CFU (colony-forming units) per m² of the rock surface, and from the Demänovská Cave of Liberty ranged from 88.6 to 347 CFU. Seventeen different free-living culturable fungi (15 filamentous fungi, one yeast, and one yeast-like fungus) were isolated from the rock surfaces of both caves. Generally, Cladosporium cladosporioides and Aspergillus flavus were the most frequently cultured species from the Demänovská Ice Cave and the Demänovská Cave of Liberty, respectively. Free-living fungi found on the rock surfaces of both caves can lead to their slow biodegradation.     

Abundance and Diversity of Psychrotolerant Cultivable Mycobiota in Winter of a Former Aluminous Shale Mine

This paper is a speleomycological report from a former aluminous shale mine in Janowiec, Poland. Fungi were identified morphologically and molecularly. Microclimatic conditions differed significantly between locations of the study. However, the external environment around the mine did not directly increase the community composition and concentration of fungi in the mine. The density of fungi isolated from the air outside the mine was 63.1 colony forming units (CFU) per 1 cm³ of air. Inside the mine, fungal density ranged from 287.5 to 655 CFU per 1 m³ from the air, 28.4 to 131.1 CFU per 1 cm² from the rock surfaces and 288.1 to 335.1 CFU per 1 cm³ from the water. Pearson correlation analysis showed that the levels of fungi isolated from the air were correlated positively with temperature, relative humidity and CO₂ concentration. The concentration of fungi isolated from the rock surfaces showed a positive correlation with air flow. Five species of filamentous fungi were isolated from the sampled external air, 10 species from the internal air, six species from the rock surface and 11 species from the water. The fungi most frequently isolated from the air and water of the mine belonged to Penicillium spp., whereas from the rock surface, Geomyces pannorum was most frequently isolated. Some of the fungi present in the mine can be psychrotolerant and pathogenic for humans and animals, and they can also cause degradation of rocks.     

Control of Listeria spp. by competitive-exclusion bacteria in floor drains of a poultry processing plant

In previous studies workers determined that two lactic acid bacterium isolates, Lactococcus lactis subsp. lactis C-1-92 and Enterococcus durans 152 (competitive-exclusion bacteria [CE]), which were originally obtained from biofilms in floor drains, are bactericidal to Listeria monocytogenes or inhibit the growth of L. monocytogenes both in vitro and in biofilms at 4 to 37 degrees C. We evaluated the efficacy of these isolates for reducing Listeria spp. contamination of floor drains of a plant in which fresh poultry is processed. Baseline assays revealed that the mean numbers of Listeria sp. cells in floor drains sampled on six different dates (at approximately biweekly intervals) were 7.5 log(10) CFU/100 cm(2) for drain 8, 4.9 log(10) CFU/100 cm(2) for drain 3, 4.4 log(10) CFU/100 cm(2) for drain 2, 4.1 log(10) CFU/100 cm(2) for drain 4, 3.7 log(10) CFU/100 cm(2) for drain 1, and 3.6 log(10) CFU/100 cm(2) for drain 6. The drains were then treated with 10(7) CE/ml in an enzyme-foam-based cleaning agent four times in 1 week and twice a week for the following 3 weeks. In samples collected 1 week after CE treatments were applied Listeria sp. cells were not detectable (samples were negative as determined by selective enrichment culture) for drains 4 and 6 (reductions of 4.1 and 3.6 log(10) CFU/100 cm(2), respectively), and the mean numbers of Listeria sp. cells were 3.7 log(10) CFU/100 cm(2) for drain 8 (a reduction of 3.8 log(10) CFU/100 cm(2)), <1.7 log(10) CFU/100 cm(2) for drain 1 (detectable only by selective enrichment culture; a reduction of 3.3 log(10) CFU/100 cm(2)), and 2.6 log(10) CFU/100 cm(2) for drain 3 (a reduction of 2.3 log(10) CFU/100 cm(2)). However, the aerobic plate counts for samples collected from floor drains before, during, and after CE treatment remained approximately the same. The results indicate that application of the two CE can greatly reduce the number of Listeria sp. cells in floor drains at 3 to 26 degrees C in a facility in which fresh poultry is processed.     

Micromycetes and actinobacteria under conditions of many years of natural cryopreservation]

Almost all of the investigated samples of the Arctic and Antarctic permafrost sediments of different genesis with ages from 5-10 thousand to 2-3 million years were found to contain viable micromycete and bacterial cells. The maximum amounts of viable cells of fungi (up to 10(4) CFU/g air-dried sample) and bacteria (up to 10(7)-10(9) CFU/g air-dried sample) were present in fine peaty sediment samples taken from different depths. The identified micromycetes belonged to more than 20 genera of the divisions Basidiomycota, Ascomycota, and Zygomycota, and some represented mitosporic fungi. Thawing the samples at 35 and 52 degrees C allowed the number of detected fungal genera to be increased by more than 30%. Aerobic heterotrophic prokaryotes were dominated by coryneform, nocardioform, and spore-forming microorganisms of the order Actinomycetales. Analysis of the isolated fungi and actinomycetes showed that most of them originated from the microbial communities of ancient terrestrial biocenoses.     

Microbiological indoor air quality in healthy buildings

There is a growing interest in indoor air quality for a better quality environment both at home and at work because many people spend at least 80% of their time indoors. The aim of our study was to evaluate the indoor concentration of airborne bacteria and fungi in a University auditorium, in an office of public buildings and in an apartment in the presence and in absence of building's occupants, building materials and furnishings. The concentrations of airborne bacteria and fungi were determined using a Surface Air System (SAS). In presence of people and furnishings the average air concentrations of bacteria (University auditorium: 925-1225 CFU m(-3); office: 493 CFU m(-3); apartment: 92-182 CFU m(-3)) were higher than in absence (respectively: 190-315 CFU m(-3); 126 CFU m(-3); 66-80 CFU m(-3)). The average air concentrations fungal were higher in presence of people and furnishings (University auditorium: 1256-1769 CFU m(-3); office: 858 CFU m(-3); apartment: 147-297 CFU m(-3)) than in absence (respectively: 301-431 CFU m(-3); 224 CFU m(-3); 102-132 CFU m(-3)). The obtained data can be considered as a step to identify acceptable levels for bioaerosols in common indoor environments.     

Enhancement of Population Densities of Pseudomonas putida PpG7 in Agricultural Ecosystems by Selective Feeding with the Carbon Source Salicylate

Sodium salicylate (1,000 μg/ml) was delivered through a drip irrigation system to agricultural field soils planted to tomato and infested with Pseudomonas putida PpG7, the host of the salicylate catabolic plasmid NAH7. In nonfumigated soils infested with approximately 10³ CFU of PpG7 per g in the top 30 cm, population densities were increased up to 112-fold within 14 days of the initial application of salicylate compared with the densities in the respective nonamended soils. Mean season-long population densities of PpG7 in the top 30 cm of soil were significantly increased (P < 0.01) from 216 CFU/g in nonamended soils to 1,370 CFU/g in salicylate-amended soils. In the respective rhizosphere soils, mean population densities of PpG7 were significantly increased (P < 0.01) from 92 to 2,066 CFU/cm of root. Soil fumigation interacted (P < 0.01) with salicylate amendment and further increased the mean population densities of PpG7 in nonrhizosphere soil by an additional 5,689 CFU/g of soil. This fumigation effect was not detected in rhizosphere soils. The effect of salicylate in increasing population densities of PpG7 in soil also was affected by inoculum level, field site, and soil depth. Proportionate differences were greater in soils infested with approximately 10³ CFU of PpG7 per g than in comparable soils infested with 10⁵ CFU/g. In low-inoculum soils, increases from salicylate amendments were 26- and 29-fold in rhizosphere and nonrhizosphere soils, respectively, and in high-inoculum soils, the respective increases were 5.6- and 5-fold. No increases of fungi able to utilize salicylate were detected in soils amended with salicylate. However, soil fumigation with metham-sodium significantly reduced (P < 0.01) population densities of fungal salicylate utilizers in rhizosphere and nonrhizosphere soils.     

Enumeration of Salmonella and Escherichia coli O157:H7 in ground beef, cattle carcass, hide and faecal samples using direct plating methods

AIM: To develop and validate high throughput methods for the direct enumeration of viable and culturable Salmonella and Escherichia coli O157:H7 in ground beef, carcass, hide and faecal (GCHF) samples from cattle. METHODS AND RESULTS: The hydrophobic grid membrane filtration (HGMF) method and the spiral plate count method (SPCM) were evaluated as rapid tools for the estimation of pathogen load using GCHF samples spiked with known levels of Salmonella serotype Typhimurium. Validation studies showed that for a single determination of each sample type the low end of the detection limits were approx. 2.0 x 10(0) CFU g(-1) for ground beef, 5.0 x 10(-1) CFU (100 cm(2))(-1) for Salmonella and 8.0 x 10(-1) CFU (100 cm(2))(-1) for E. coli O157:H7 on carcasses, 4.0 x 10(1) CFU (100 cm(2))(-1) for hide and 2.0 x 10(2) CFU g(-1) for faecal samples. In addition, ground beef (n = 609), carcass (n = 1520) and hide (n = 3038) samples were collected from beef-processing plants and faecal samples (n = 3190) were collected from feed-lot cattle, and these samples were tested for the presence of Salmonella and E. coli O157:H7 by enrichment and enumeration methods. CONCLUSIONS: The direct enumeration methods described here are amenable to high throughput sample processing and were found to be cost-effective alternatives to other enumeration methods for the estimation of Salmonella and E. coli O157:H7, in samples collected during cattle production and beef processing. SIGNIFICANCE AND IMPACT OF THE STUDY: Use of the methods described here would allow for more routine testing and quantification data collection, providing useful information about the effectiveness of beef processing intervention strategies.     

The mycoflora and toxicity of feedstuffs from a production plant in córdoba, Argentina

Feedstuffs used for poultry nutrition in Argentina were analyzed for fungal flora and natural incidence of mycotoxins. Survey of 120 samples of poultry feeds, taken from May 1998 to April 1999, showed the presence of 15 genera of filamentous fungi. The predominant genera wereFusarium spp. andPenicillium ssp., isolated in 67.5 % of the samples, followed byAspergillus spp. (57.5 %). Yeast, were significantly isolated from most of the samples. Species identification was carried down for the toxigenic genera. Fungal total counts of poultry feeds ranged from 2.0 × 10³ to 3.0 × 10⁵ CFU g^-1 The fungal total counts during two months of sampling, were slightly over the limit value of 1 × 105 CFU g^-1, which ensure the hygienic quality of the feed. Potentially toxicogenic species presented moderate mean colony counts. Many of the fungi isolated from poultry feeds are mycotoxin producers. Fumonisins had the highest incidence, and were found in 97 % of the analyzed samples followed by aflatoxin B₁ (46 %), zearalenone (18 %) and deoxynivalenol (6 %). On the co-occurrence of both carcinogenic mycotoxins, all of the FBs contaminated feed samples were co-contaminated with AFB₁. The results show the relevance of the samples screening for viable fungi propagules and the surveillance of their associated mycotoxins in poultry feeds.     

Levels of bacteria, fungi, and endotoxin in bulk and aerosolized corn silage

Three samples of silage taken from the surface of a silo and from depths of 20 and 45 cm in the silo were studied for identification of the potential agents causing symptoms of organic dust toxic syndrome. The samples were examined by dilution plating before and after aerosolization in an acoustical dust generator. Aerosol samples were collected by liquid impinger and filter cassettes. The samples were examined for total aerobic bacteria, anaerobic bacteria, gram-negative bacteria, lactobacilli, listeriae, thermophilic actinomycetes, fungi, and endotoxin. Very high levels of total aerobic bacteria and fungi were found in the surface sample (up to 10(9) CFU/g in the bulk sample and up to 10(9) CFU/m3 after aerosolization), whereas the corresponding values from the deepest site were 100 to 50,000 times lower. Aspergillus fumigatus predominated among the fungi, whereas Bacillus and gram-negative organisms (Pseudomonas, Alcaligenes, Citrobacter, and Klebsiella species) prevailed among bacteria. Thermophilic actinomycetes occurred in numbers up to 10(7) CFU/g in the bulk samples, whereas anaerobic bacteria, lactobacilli, and listeriae were only few or absent. The concentration of endotoxin was high in the surface sample (up to 211.4 Endotoxin Units/mg) and about 200-fold lower in the sample from the deepest site. The results show that contact with dust from the surface of silage carries the risk of exposure to high concentrations of microorganisms, of which A. fumigatus and endotoxin-producing bacteria are the most probable disease agents.     

Levels of bacteria, fungi, and endotoxin in bulk and aerosolized corn silage.

Three samples of silage taken from the surface of a silo and from depths of 20 and 45 cm in the silo were studied for identification of the potential agents causing symptoms of organic dust toxic syndrome. The samples were examined by dilution plating before and after aerosolization in an acoustical dust generator. Aerosol samples were collected by liquid impinger and filter cassettes. The samples were examined for total aerobic bacteria, anaerobic bacteria, gram-negative bacteria, lactobacilli, listeriae, thermophilic actinomycetes, fungi, and endotoxin. Very high levels of total aerobic bacteria and fungi were found in the surface sample (up to 10(9) CFU/g in the bulk sample and up to 10(9) CFU/m3 after aerosolization), whereas the corresponding values from the deepest site were 100 to 50,000 times lower. Aspergillus fumigatus predominated among the fungi, whereas Bacillus and gram-negative organisms (Pseudomonas, Alcaligenes, Citrobacter, and Klebsiella species) prevailed among bacteria. Thermophilic actinomycetes occurred in numbers up to 10(7) CFU/g in the bulk samples, whereas anaerobic bacteria, lactobacilli, and listeriae were only few or absent. The concentration of endotoxin was high in the surface sample (up to 211.4 Endotoxin Units/mg) and about 200-fold lower in the sample from the deepest site. The results show that contact with dust from the surface of silage carries the risk of exposure to high concentrations of microorganisms, of which A. fumigatus and endotoxin-producing bacteria are the most probable disease agents.     

Concentration and distribution characteristics of airborne fungi in indoor and outdoor air of Tehran subway stations

The concentration and distribution characteristics of airborne fungi were investigated in indoor and outdoor air of two metro stations (Imam Khomeini and Sadeghiyeh stations) in Tehran subway. Samples were taken from indoor air at each station from platform and ticket office area also from adjacent outdoor air of each station. Indoor sampling was conducted for two types of trains, old and new. The concentration of airborne fungi ranged from 21 CFU/m³ at the outdoor air of Imam Khomeini station to 1,402 CFU/m³ in the air samples collected from the platform of this station. Results showed that airborne fungi concentrations at indoor air were higher than the outdoor air (p < 0.05), and fungal levels significantly correlated with the number of passengers (p < 0.05; r = 0.68) and RH % (p < 0.05; r = 0.43). Sixteen genera of fungi were isolated in all sampled environments. The predominant genera identified in indoor and outdoor air were Penicillium spp. (34.88 % of total airborne fungi) and Alternaria spp. (29.33 % of total airborne fungi), respectively. The results of this study showed that the indoor air quality in subway is worse than the outdoor air.     

乙草胺和甲胺磷对农田黑土可培养真菌数量及种群结构的影响

应用传统及PCR-DGGE方法(denaturing gradient gel electrophoresis),分别对不同浓度乙草胺、甲胺磷胁迫下黑土中可培养真菌CFU(colony forming units)、种群丰富度(richness)及种群结构动态变化规律进行了研究.结果表明,在实验室微域条件下,乙草胺对黑土可培养真菌CFU的影响随处理浓度的增加而抑制作用增强,表现出由低浓度(50 mg·kg^-1)时的刺激生长到高浓度(250 mg·kg^-1)时的长期抑制效应;250 mg·kg^-1甲胺磷在8周处理过程中对土壤可培养真菌生长具有显著的刺激效应,使可培养真菌CFU比对照增加10倍,但50和150 mg·kg^-1甲胺磷处理对土壤可培养真菌CFU无显著影响.种群丰富度系数分析结果表明,高、中浓度乙草胺处理可使土壤可培养真菌种群丰富度不可逆地降低.土壤真菌rDNA特异PCR-DGGE聚类分析结果表明,不同浓度乙草胺、甲胺磷处理均不同程度地对土壤可培养真菌的种群组成和结构造成影响,其中甲胺磷尤为显著.