Carbon Source Utilization Patterns Research Articles

Analysis and interpretation of community-level physiological profiles in microbial ecology

A rapid, community-level approach for assessing patterns of sole carbon source utilization by mixed microbial samples has been used increasingly to study microbial community dynamics. The method involves direct inoculation of environmental samples into Biolog microtiter plates, and uses color formation from reduction of a tetrazolium dye to assess utilization of 95 separate sole carbon sources during a 2–7 day incubation period. This approach, called community-level physiological profiling, has been effective at distinguishing spatial and temporal changes in microbial communities. Effective analysis of the multivariate profiles of carbon source utilization requires separation of effects caused by differences in inoculum density (i.e. overall rate of color development) from effects caused by differences in the types or activities of organisms present (i.e. relative rates, or pattern, of carbon source utilization). Further experimental studies are required to better define what fraction of the original inoculum responds in the assay, and if the profiles provide structural and/or functional information.

Refining numerical approaches for analyzing soil microbial community catabolic profiles based on carbon source utilization patterns

Despite several limitations, community level catabolic profiles (CLCPs) based on carbon source utilization patterns are extensively used in ecological surveys to study the functional diversity of soil microbial communities. Our paper discusses two ways by which numerical approaches currently applied to CLCP data may be refined. First, we discuss the negative relationship between the sensitivity of a functional diversity index (D f ) and the number of catabolic reactions used to calculate this index. Consequently, we propose that D f be based on specific subsets of substrates to describe the diversity among functional subgroups of the soil microbial community. Secondly, we discuss the current lack of a proper inferential test of significance for testing treatment effects on CLCPs. Permutation multivariate analysis of variance (PMANOVA) is thus proposed as a robust statistical alternative for comparing treatment effects on multiple response variables that are not independent. For illustrative purposes, we have compared the sensitivity of principal component analysis (PCA) with that of PMANOVA, performed on the same CLCP data set.

Microbial Characteristics and Nitrogen Transformation in Planted Soil Filter for Domestic Wastewater Treatment

We studied an experimental horizontal subsurface-flow planted sand filter in Kodijärve, Estonia. We measured the microbial biomass, nitrogen immobilization, potential nitrification, soil respiration, multiple carbon source utilization patterns of the microbial consortia of the soil samples, the carbon, nitrogen, and phosphorus content of the soil samples, the water quality and physicochemical indicators in water sampling wells as well as emissions of CO2, N2, NO2, and CH4 from the two beds (the dry bed and the wet bed) in the wetland. The potential nitrification of the upper layer of the dry bed could not be attributed primarily to autotrophic nitrification, or the nitrifying bacteria in this layer could be facultative heterotrophs, whereas autotrophic nitrification is predominant in the upper layer of the wet bed. It also was found that changing aeration conditions in the lower layer of the dry bed have resulted in a lower diversity of the microbial community and led to a relative depletion of easily degradable soil carbon resources.

Red alder ( Alnus rubra) alters community-level soil microbial function in conifer forests of the Pacific Northwest, USA

Nitrogen-fixing tree species have been shown to improve site fertility and increase N transformation rates, but the influence of N-fixing plants on the soil microbial community as a whole is largely unknown. We used patterns of individual carbon-source utilization and enzyme activities to assess the relative effects of N-fixing red alder on the soil microbial community in three adjacent stands (pure conifer, mixed alder-conifer, and pure alder) of a highly productive coastal Oregon forest where the density of red alder has been experimentally manipulated for over 65 years. Two major patterns were revealed: (1) bacterial and fungal carbon-source utilization patterns in soil from pure conifer stands were significantly different from both pure alder soils and mixed conifer-alder soils, while there was no difference in substrate utilization patterns between soils from the mixed alder-conifer and pure alder stands; and (2) the activities of nine extracellular enzymes involved in ligno-cellulose degradation and the mineralization of organic nitrogen, phosphate, and sulfate compounds were all significantly greater in pure alder soils compared to either pure conifer or mixed conifer-alder soils. Our results show that, in addition to an overall increase in soil fertility, microbial biomass, and microbial activity, the presence of N-fixing red alder significantly alters the physiological profile of the microbial community-even in an ecosystem already of high N status.

Effects of lead and cadmium nitrate on biomass and substrate utilization pattern of soil microbial communities

A study was conducted to evaluate the effects of different concentrations of lead (Pb) and cadmium (Cd) applied as their nitrates on soil microbial biomass carbon (C mic) and nitrogen (N mic), and substrate utilization pattern of soil microbial communities. The C mic and N mic contents were determined at 0, 14, 28, 42 and 56 days after heavy metal application (DAA). The results showed a significant decline in the C mic for all Pb and Cd amended soils from the start to 28 DAA. From 28 to 56 DAA, C mic contents changed non-significantly for all other treatments except for 600 mg kg −1 Pb and 100 mg kg −1 Cd in which it declined significantly from 42 to 56 DAA. The N mic contents also decreased significantly from start to 28 DAA for all other Pb and Cd treatments except for 200 mg kg −1 Pb which did not show significant difference from the control. Control and 200 mg kg −1 Pb had significantly lower soil microbial biomass C:N ratio as compared with other Pb treatments from 14 to 42 DAA, however at 56 DAA, only 1000 mg kg −1 Pb showed significantly higher C:N ratio compared with other treatments. No significant difference in C:N ratio for all Cd treated soils was seen from start to 28 DAA, however from 42 to 56 DAA, 100 mg kg −1 Pb showed significantly higher C:N ratio compared with other treatments. On 56 DAA, substrate utilization pattern of soil microbial communities was determined by inoculating Biolog ECO plates. The results indicated that Pb and Cd addition inhibited the functional activity of soil microbial communities as indicated by the intensity of average well color development (AWCD) during 168 h of incubation. Multivariate analysis of sole carbon source utilization pattern demonstrated that higher levels of heavy metal application had significantly affected soil microbial community structure.

Functional diversity of bacterioplankton assemblages in western Antarctic seawaters during late spring

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 292:13-21 (2005) - doi:10.3354/meps292013 Functional diversity of bacterioplankton assemblages in western Antarctic seawaters during late spring Maria Montserrat Sala*, Laura Arin, Vanessa Balagué, Jordi Felipe, Òscar Guadayol, Dolors Vaqué Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CMIMA (CSIC), P. Marítim de la Barceloneta 37–49, 08003 Barcelona, Spain *Email: msala@icm.csic.es ABSTRACT: Functional diversity and aminopeptidase activity (AMA) in bacterial assemblages were determined in western Antarctic waters during late spring 2002. Functional diversity was assayed by the patterns of sole carbon source utilization in Biolog-ECO MicroplatesTM and AMA with the fluorogenic substrate leucine 7-amido-4-methylcoumarin. n-acetyl-d-glucosamine and d-cellobiose were the most used carbohydrates. This suggested that used dissolved organic carbon (DOC) was mostly of either zoo-or phytoplankton origin. Principal component analysis of the sole carbon source utilization profiles separated the samples according to salinity and temperature. This separation corresponded roughly with the 3 areas of study: Bransfield Strait (BR), Gerlache Strait (GE) and Bellingshausen Sea (BE). AMA was higher in the upper 40 m, probably associated with the higher organic matter load. Phytoplankton biomass was the factor that accounted for the highest variance in AMA, but did not have a clear influence on functional diversity of bacterioplankton. Our findings indicate that differences in functional diversity of bacterioplankton populations in western Antarctic waters are not directly related to phytoplanktonic abundance. This suggests that bacteria could utilize other carbon sources than DOC freshly released by phytoplankton. KEY WORDS: Bacterial activity · Functional diversity · Biolog · Aminopeptidase · Ectoenzyme · Antarctica Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 292. Online publication date: May 12, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 Inter-Research.

Molecular diversity of tannic acid degrading bacteria isolated from tannery soil

The aim of this study was to enrich and isolate bacteria from a tannery soil that were capable of utilizing tannic acid and gallic acid as sole source of carbon aerobically, and to characterize their diversity in order to identify efficient strains that can be used for tannin bioremediation. Bacterial strains were isolated after enrichment in minimal medium with tannic acid or gallic acid as sole carbon source. Polymerase chain reaction (PCR) restricted fragment length polymorphism of 16S rDNA [amplified ribosomal DNA restriction analysis (ARDRA)] and BOX-PCR was used to characterize their diversity. Two strains showing relatively high efficiency in degrading tannic acid and gallic acid were identified on the basis of carbon source utilization pattern (BIOLOG) and 16S rDNA sequence. Bacterial strains capable of degrading tannic acid and gallic acid could be grouped into six and seven clusters on the basis of ARDRA and BOX-PCR, respectively. On the basis of 16S rDNA sequence, the most efficient isolate degrading tannic acid belonged to Pseudomonas citronellolis, whereas the most efficient gallic acid degrader showed maximum phylogenetic relatedness to P. plecoglossicida. Aerobic tannic acid degraders such as the two strains isolated in this study can be used for tannin bioremediation, and in the study of genes involved in the production of tannase, an industrially important enzyme.

Oceanicola granulosus gen. nov., sp. nov. and Oceanicola batsensis sp. nov., poly-beta-hydroxybutyrate-producing marine bacteria in the order 'Rhodobacterales'.

Three Gram-negative, chemoheterotrophic, non-motile, rod-shaped bacterial strains that accumulate poly-beta-hydroxybutyrate granules were isolated from the Bermuda Atlantic Time-series Study site by high-throughput culturing methods and characterized by polyphasic approaches. DNA-DNA hybridization, DNA G+C content and phylogenetic analyses based on 16S rRNA gene sequences divided the three isolates into two distinct genospecies that were clearly differentiated by fatty acid profiles, carbon source utilization patterns, antibiotic susceptibility and biochemical characteristics. The strains utilized a wide range of substrates, including pentoses, hexoses, oligosaccharides, sugar alcohols, organic acids and amino acids. DNA G+C contents were 71.5, 70.9 and 67.3 mol% for strains HTCC2516T, HTCC2523 and HTCC2597T, respectively. The most dominant fatty acid was 18 : 1omega7c in strains HTCC2516T and HTCC2523, and cyclo 19 : 0 in strain HTCC2597T. The type strains HTCC2516T and HTCC2597T were clearly differentiated by the presence or absence of 12 : 0, 12 : 1omega11c, 14 : 0, 15 : 0 and methyl 18 : 1. Phylogenetic analyses indicated that the strains formed a distinct monophyletic lineage within the Roseobacter clade in the order 'Rhodobacterales' of the Alphaproteobacteria, and which did not associate with any of the described genera. Genotypic and phenotypic differences of the isolates from the previously described genera support the description of Oceanicola granulosus gen. nov., sp. nov. with the type strain HTCC2516T (=ATCC BAA-861T=DSM 15982T=KCTC 12143T) and of Oceanicola batsensis sp. nov. with the type strain HTCC2597T (=ATCC BAA-863T=DSM 15984T=KCTC 12145T).

Methylobacterium populi sp. nov., a novel aerobic, pink-pigmented, facultatively methylotrophic, methane-utilizing bacterium isolated from poplar trees (Populus deltoides x nigra DN34).

A pink-pigmented, aerobic, facultatively methylotrophic bacterium, strain BJ001T, was isolated from internal poplar tissues (Populus deltoidesxnigra DN34) and identified as a member of the genus Methylobacterium. Phylogenetic analyses showed that strain BJ001T is related to Methylobacterium thiocyanatum, Methylobacterium extorquens, Methylobacterium zatmanii and Methylobacterium rhodesianum. However, strain BJ001T differed from these species in its carbon-source utilization pattern, particularly its use of methane as the sole source of carbon and energy, an ability that is shared with only one other member of the genus, Methylobacterium organophilum. In addition, strain BJ001T is the only member of the genus Methylobacterium to be described as an endophyte of poplar trees. On the basis of its physiological, genotypic and ecological properties, the isolate is proposed as a member of a novel species of the genus Methylobacterium, Methylobacterium populi sp. nov. (type strain, BJ001T=ATCC BAA-705T=NCIMB 13946T).

Phylogeny based on 16S rDNA and nifH sequences of Ralstonia taiwanensis strains isolated from nitrogen-fixing nodules of Mimosa pudica, in India.

Bacterial symbionts present in the indeterminate-type nitrogen (N)-fixing nodules of Mimosa pudica grown in North and South India showed maximum similarity to Ralstonia taiwanensis on the basis of carbon-source utilization patterns and 16S rDNA sequence. Isolates from the nodules of M. pudica from North India and South India showed identical ARDRA (Amplified Ribosomal DNA Restriction Analysis) patterns with Sau3AI and RsaI, but AluI revealed dimorphy between the North Indian and South Indian isolates. Alignment of 16S rDNA sequences revealed similarity of North Indian isolates with an R. taiwanensis strain isolated from M. pudica in Taiwan, whereas South Indian isolates showed closer relatedness with the isolates from Mimosa diplotricha. Alignment of nifH sequences from both North Indian and South Indian isolates with that of the related isolates revealed their closer affinity to alpha-rhizobia, suggesting that nif genes in the beta-rhizobia might have been acquired from alpha-rhizobia via lateral transfer during co-occupancy of nodules by alpha-rhizobia and progenitors of R. taiwanensis, members of the beta-subclass of Proteobacteria. Immunological cross-reaction of the bacteroid preparation of M. pudica nodules showed strong a positive signal with anti-dinitrogenase reductase antibody, whereas a weak positive cross-reaction was observed with free-living R. taiwanensis grown microaerobically in minimal medium with and without NH4Cl. In spite of the expression of dinitrogenase reductase under free-living conditions, acetylene reduction was not observed under N-free conditions even after prolonged incubation.

Substrate utilization pattern, biomass and activity of microbial communities in a sequence of heavy metal-polluted paddy soils

The microbial biomass, activity and substrate utilization pattern of seven Chinese paddy soils with different heavy metal concentrations in the vicinity of a Cu–Zn smelter was investigated. Microbial biomass and basal respiration were negatively affected by the elevated metal levels. Two important biological parameters, namely, the microbial biomass-C (C mic)/organic C (C org) ratio and metabolic quotient were closely correlated to heavy metal stress. There was a significant decrease in the C mic/C org ratio and an increase in the metabolic quotient with increasing metal concentration. Multivariate analysis of sole carbon source utilization pattern demonstrated that heavy metal pollution had a significant impact on microbial community structure and there was a threshold metal concentration for substrate utilization pattern. However, the average well colour development (AWCD) of the carbon sources in Biolog plates did not vary in a consistent manner with the microbial biomass or heavy metal concentration.

Application of carbon source utilization patterns to measure the metabolic similarity of complex dental plaque biofilm microcosms.

Biolog technology was applied to measure the metabolic similarity of plaque biofilm microcosms, which model the complex properties of dental plaque in vivo. The choice of Biolog plate, incubation time, and incubation conditions strongly influenced utilization profiles. For plaque biofilm microcosms, Biolog GP2 plates incubated anaerobically in an H2-free atmosphere gave the clearest profile. To test the application of the Biolog GP2 assay, plaque microcosms were developed under different nutrient conditions in which the frequency of sucrose application was varied. Cluster analysis of Biolog GP2 data from 10 microcosm biofilms correlated with sucrose frequency. Aciduric bacteria (Streptococcus mutans plus lactobacilli) predominated in the plaques receiving high-frequency sucrose applications. Agreement between the Biolog GP2 groupings with nutrient and compositional changes suggests that Biolog analysis is a valuable technique for analyzing the metabolic similarity of dental plaque biofilm microcosms and other high-nutrient or predominantly anaerobic ecosystems.

Spatial Heterogeneity of Bacterial Assemblages in Marine Sediments: The Influence of Deposit Feeding byBalanoglossus aurantiacus .

Densities and substrate utilization patterns of the bacterial assemblages of three intertidal sandflats were contrasted to investigate spatial heterogeneity. Possible influence of deposit-feeding Balanoglossus aurantiacus (Enteropneusta: Ptychoderidae) was also studied by comparing samples taken from the faecal mounds with surrounding sediments. While there were no significant differences in total bacterial abundance, carbon source utilization patterns, determined using Biolog GN microtitre plates, differed among the sandflats and within the sandflats for samples from grids more than 10m apart. No consistent quantitative or qualitative differences were detected among clusters of ambient sediment samples taken less than 0·5m apart. Qualitative differences in microbial assemblages were found between faecal mounds and ambient (>10cm apart) sediment within a single intertidal flat. These differences were in part due to digestive removal of bacteria, as heterotrophic plate counts and response in Biolog plates (average well colour development, AWCD) were significantly higher for the surrounding sediment. However, when Biolog profiles were normalized to AWCD, it became clear that gut passage resulted in structural shifts in bacterial assemblages. These changes were due to digestion of a subset of ingested bacteria with the concomitant stimulation (or inoculation) of other groups, which were largely unculturable under the conditions employed. These findings illustrate that deposit feeding effects spatial heterogeneity in sedimentary bacterial assemblages. Given the ephemeral nature of these disturbed patches, however, it is not yet clear that deposit feeding is a primary determinant of microbial community structure in this sedimentary landscape.

Characterization of soils based on the response of indigenous bacterial communities to chemical stress : Evaluation of bacterial strains isolated from the soils treated with catechol using patterns of carbon source utilization

Characterization of soils based on the response of indigenous bacterial communities to chemical stress : Evaluation of bacterial strains isolated from the soils treated with catechol using patterns of carbon source utilization

Production of mannitol by a novel strain of Candida magnoliae

A novel microorganism was isolated which is able to produce mannitol when grown in the presence of fructose and glucose as carbon sources. In flask culture in a medium containing 150 g fructose l−1, it yielded 67 g mannitol l−1 after 168 h. In fed-batch culture with 3–12% (w/v) fructose, production reached a maximum of 209 g mannitol l−1 after 200 h, corresponding to an 83% yield and a 1.03 g l−1 h−1 productivity. The isolated strain was identified as Candida magnoliae based on identical sequences in the D1/D2 domain of its 26S rDNA and a similar carbon source utilization pattern with C. magnoliae reference strains.

Ecophysiological Characterization of Rhizosphere Bacterial Communities at Different Root Locations and Plant Developmental Stages of Cucumber Grown on Rockwool.

Bacterial communities from the rhizosphere of cucumber were characterized with respect to growth rates and carbon source utilization, in order to develop a selection strategy for biocontrol agents against Pythium aphanidermatum. Rhizosphere samples were collected from different root regions (root tips, the root base, and the intermediate region where lateral roots emerge) and developmental stages (the seedling, vegetative, and generative stage) from plants cultivated on reused rockwool. By colony counts on 1/10 strength TSA on subsequent days after plating, percentages of fast- and slow-growing isolates (i.e., forming visible colonies within 2 days, or after 3 or more days, respectively) were determined for each rhizosphere sample. At all plant developmental stages, root tips had the highest percentages of fast growing isolates, and root bases the lowest. During plant growth, the relative amounts of slowly growing bacteria increased. Community-level carbon source utilization was determined for the different rhizosphere samples with Biolog GN plates. Principal component analysis showed that rhizosphere samples from different developmental stages and root locations had distinct carbon source utilization patterns. Communities from root tips of seedlings showed the highest utilization of several monosaccharides. Communities from tips and intermediate regions of plants in the vegetative stage utilized relatively many amino acids and several organic acids, and in the generative stage, more di- and polysaccharides were used. Root base samples scored low with respect to carbon source utilization, except for some disaccharides. From the different rhizosphere samples, 826 bacteria, randomly collected from 1/10 strength TSA plates, were screened on the utilization of 9 carbon sources. The 9 selected carbon sources were chosen because they are reported to occur in the rhizosphere, to be used by the zoospores of Pythium in the infection process, or appeared to be discriminant in the analysis of community-level carbon source utilization performed in this study. It appeared that monosaccharides (glucose and fucose), amino acids (alanine and asparagine), and organic acids (galacturonic, succinic, and linoleic acid) were used for growth mainly by bacteria from the root tips, and to a lesser extent from the intermediate region, of young plants. Disaccharides were predominantly utilized by isolates from plants in the vegetative stage. Overall, the results indicated that growth rates and carbon source utilization reflect the adaptation of bacteria to the rhizosphere environment. The possibility of using these characteristics to screen for rhizosphere competent biocontrol agents that compete for substrates with P. aphanidermatum is discussed.

An altered Pseudomonas diversity is recovered from soil by using nutrient-poor Pseudomonas-selective soil extract media.

We designed five Pseudomonas-selective soil extract NAA media containing the selective properties of trimethoprim and sodium lauroyl sarcosine and 0 to 100% of the amount of Casamino Acids used in the classical Pseudomonas-selective Gould's S1 medium. All of the isolates were confirmed to be Pseudomonas by a Pseudomonas-specific OprF antibody and a Pseudomonas-specific PCR targeting 16S ribosomal DNA. The Pseudomonas isolates were characterized by classical physiological tests, repetitive extragenic palindromic-PCR, Fourier transform infrared spectroscopy, and carbon source utilization patterns. Several of these analyses showed that the amount of Casamino Acids significantly influenced the diversity of the recovered Pseudomonas isolates. Furthermore, the data suggested that specific Pseudomonas subpopulations were represented on the nutrient-poor media. The NAA 1:100 medium, containing ca. 15 mg of organic carbon per liter, consistently gave significantly higher Pseudomonas CFU counts than Gould's S1 when tested on four Danish soils. NAA 1:100 may, therefore, be a better medium than Gould's S1 for enumeration and isolation of Pseudomonas from the low-nutrient soil environment.

Attached and unattached microbial communities in a simulated basalt aquifer under fracture- and porous-flow conditions.

Bench scale column studies were used to examine the partitioning of microorganisms between groundwater and a geologic medium and to examine the effect of hydrogeology (i.e., porous- versus fracture-flow) on organism partitioning. Replicated columns were constructed with intact basalt core segments that contained natural fractures and with the same basalt crushed into particles. The columns were perfused with groundwater, and upon reaching a steady state, the columns were sacrificed and the attached and unattached communities were analyzed by multiple approaches. The analyses included the total number of cells, the phylogenetic affiliation of the cells (i.e., the alpha, beta, and gamma subclasses of the class Proteobacteria and gram positives with high G+C DNA content) by fluorescent in situ hybridization (FISH), number and taxonomic affiliation by fatty acid methyl ester profiles of culturable heterotrophs, most-probable-number estimates of methanotrophs and phenol oxidizers, and whole-community sole carbon source utilization patterns from Biolog GN microplates. In the packed columns, about 99% of the total biomass (per cubic centimeter of porous medium) was attached to the geologic medium. Lack of equitable units precluded a comparison of attached and unattached biomasses in the fractured columns where the attached biomass was expressed per unit of surface area. Compositional differences in the attached and unattached communities were evidenced by (i) the recovery of Pseudomonas stutzeri, an Enterococcus sp., and Bacillus psychrophilus from the groundwater and not from the basalt, (ii) differences between community carbon source utilization patterns, and (iii) the relative abundances of different phylogenetic groups estimated by FISH in both column types. In the packed columns, attached communities were depleted of members of the alpha- and beta-Proteobacteria subclasses in comparison to those in the corresponding groundwater. In the fractured columns, attached communities were enriched in gram-positive Bacteria and gamma-Proteobacteria and depleted of beta-Proteobacteria, in comparison to those in the corresponding groundwater. Segregation of populations and their activities, possibly modified by attachment to geologic media, may influence contaminant fate and transport in the subsurface and impact other in situ applications.

Comparative Effects of a Genetically Engineered Insect Virus and a Growth-Regulating Insecticide on Microbial Communities in Aquatic Microcosms

The effects of a genetically engineered insect baculovirus on indigenous aquatic microbial communities were determined in closed, recirculating aquatic microcosms, and compared with the effects of a natural strain of the virus and of a growth-regulating insecticide, Dimilin. The recombinant virus was a nuclear polyhedrosis virus (NPV) of the spruce budworm (Choristoneura fumiferana (Cf)) with a lacZ marker gene inserted into the egt region of the CfNPV. The natural virus was Ireland strain CfNPV. Microbial measurement endpoints included decomposition activity (mass loss of organic material), respiration on two different substrates (O2 consumption), heterotrophic bacterial abundance (plate counts), and microbial community metabolic profiles (carbon source utilization patterns in Biolog GN microplates). Viral DNA of both the natural strain and the recombinant viruses, detected by polymerase chain reaction techniques, settled out of the microcosm water and accumulated on bottom substrates within 3 days of the microcosm inoculations. The viral DNA persisted in bottom substrates for the duration of the 21-day experimental period, although there was some evidence that the recombinant virus was less stable than the natural strain in particulate organic matter. No significant changes in microbial decomposition or respiration activity, bacterial abundance, or average metabolic responses were detected by a time trend analysis in microcosms inoculated with either the lacZ recombinant virus or the natural Ireland strain CfNPV. Significant effects on microbial decomposition and respiration activity were detected in microcosms treated with the growth-regulating insecticide at, and above, the expected environmental concentrations. Despite significant effects on microbial community functional attributes in Dimilin-treated microcosms, there were no detectable changes in community structure in terms of metabolic profiles or bacterial abundance.

A comparison of sole carbon source utilization patterns and phospholipid fatty acid profiles to detect changes in the root microflora of hydroponically grown crops

A comparison of sole carbon source utilization patterns and phospholipid fatty acid profiles to detect changes in the root microflora of hydroponically grown crops