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PubMed2001

Biology of extremophilic and extremotolerant methanotrophs.

This review summarizes recent findings on the biology of obligate methanotrophic bacteria living in various extreme environments. By using molecular ecology techniques, it has become clear that obligate methanotrophs are ubiquitous in nature and well adapted to high or low temperature, pH and salinity. The isolation and characterization of pure cultures has led to the discovery of several new genera and species of extremophilic/tolerant methanotrophs. Their major physiological role is participation in the methane cycle and supplying C(1) intermediates and various metabolites to other members of microbial communities in extreme ecosystems. To survive under extreme conditions, methanotrophs have developed diverse structure-function adaptive mechanisms including cell-surface layer formation, changes in cellular phospholipid composition and de novo synthesis of organic osmolytes such as ectoine, 5-oxoproline and sucrose. However, despite the above advances, basic knowledge of other stress protectants, as well as bioenergetic and genetic aspects of methanotroph adaptation, is still lacking. This information is necessary for better understanding the molecular mechanisms underlying the versatility of methanotrophs and for the development of novel biotechnological processes.

Cold Temperature↗

PubMed2005

Culturable bacterial symbionts isolated from two distinct sponge species (Pseudoceratina clavata and Rhabdastrella globostellata) from the Great Barrier Reef display similar phylogenetic diversity.

The diversity of the culturable microbial communities was examined in two sponge species-Pseudoceratina clavata and Rhabdastrella globostellata. Isolates were characterized by 16S rRNA gene sequencing and phylogenetic analysis. The bacterial community structures represented in both sponges were found to be similar at the phylum level by the same four phyla in this study and also at a finer scale at the species level in both Firmicutes and Alphaproteobacteria. The majority of the Alphaproteobacteria isolates were most closely related to isolates from other sponge species including alpha proteobacterium NW001 sp. and alpha proteobacterium MBIC3368. Members of the low %G + C gram-positive (phylum Firmicutes), high %G + C gram-positive (phylum Actinobacteria), and Cytophaga-Flavobacterium-Bacteroides (phylum Bacteroidetes) phyla of domain Bacteria were also represented in both sponges. In terms of culturable organisms, taxonomic diversity of the microbial community in the two sponge species displays similar structure at phylum level. Within phyla, isolates often belonged to the same genus-level monophyletic group. Community structure and taxonomic composition in the two sponge species P. clavata and Rha. globostellata share significant features with those of other sponge species including those from widely separated geographical and climatic regions of the sea.

Animals↗

PubMed2003

Bioaugmentation as a tool to protect the structure and function of an activated-sludge microbial community against a 3-chloroaniline shock load.

Bioaugmentation of bioreactors focuses on the removal of xenobiotics, with little attention typically paid to the recovery of disrupted reactor functions such as ammonium-nitrogen removal. Chloroanilines are widely used in industry as a precursor to a variety of products and are occasionally released into wastewater streams. This work evaluated the effects on activated-sludge reactor functions of a 3-chloroaniline (3-CA) pulse and bioaugmentation by inoculation with the 3-CA-degrading strain Comamonas testosteroni I2 gfp. Changes in functions such as nitrification, carbon removal, and sludge compaction were studied in relation to the sludge community structure, in particular the nitrifying populations. Denaturing gradient gel electrophoresis (DGGE), real-time PCR, and fluorescent in situ hybridization (FISH) were used to characterize and enumerate the ammonia-oxidizing microbial community immediately after a 3-CA shock load. Two days after the 3-CA shock, ammonium accumulated, and the nitrification activity did not recover over a 12-day period in the nonbioaugmented reactors. In contrast, nitrification in the bioaugmented reactor started to recover on day 4. The DGGE patterns and the FISH and real-time PCR data showed that the ammonia-oxidizing microbial community of the bioaugmented reactor recovered in structure, activity, and abundance, while the number of ribosomes of the ammonia oxidizers in the nonbioaugmented reactor decreased drastically and the community composition changed and did not recover. The settleability of the activated sludge was negatively influenced by the 3-CA addition, with the sludge volume index increasing by a factor of 2.3. Two days after the 3-CA shock in the nonbioaugmented reactor, chemical oxygen demand (COD) removal efficiency decreased by 36% but recovered fully by day 4. In contrast, in the bioaugmented reactor, no decrease of the COD removal efficiency was observed. This study demonstrates that bioaugmentation of wastewater reactors to accelerate the degradation of toxic chlorinated organics such as 3-CA protected the nitrifying bacterial community, thereby allowing faster recovery from toxic shocks.

Ammonia↗

PubMed2005

A persistent, productive, and seasonally dynamic vibriophage population within Pacific oysters (Crassostrea gigas).

In an effort to understand the relationship between Vibrio and vibriophage populations, abundances of Vibrio spp. and viruses infecting Vibrio parahaemolyticus (VpVs) were monitored for a year in Pacific oysters and water collected from Ladysmith Harbor, British Columbia, Canada. Bacterial abundances were highly seasonal, whereas high titers of VpVs (0.5 x 10(4) to 11 x 10(4) viruses cm(-3)) occurred year round in oysters, even when V. parahaemolyticus was undetectable (< 3 cells cm(-3)). Viruses were not detected (<10 ml(-1)) in the water column. Host-range studies demonstrated that 13 VpV strains could infect 62% of the V. parahaemolyticus strains from oysters (91 pairings) and 74% of the strains from sediments (65 pairings) but only 30% of the water-column strains (91 pairings). Ten viruses also infected more than one species among V. alginolyticus, V. natriegens, and V. vulnificus. As winter approached and potential hosts disappeared, the proportion of host strains that the viruses could infect decreased by approximately 50% and, in the middle of winter, only 14% of the VpV community could be plated on summer host strains. Estimates of virus-induced mortality on V. parahaemolyticus indicated that other host species were required to sustain viral production during winter when the putative host species was undetectable. The present study shows that oysters are likely one of the major sources of viruses infecting V. parahaemolyticus in oysters and in the water column. Furthermore, seasonal shifts in patterns of host range provide strong evidence that the composition of the virus community changes during winter.

Animals↗

PubMed2026

Gut microbiome composition and predicted functions relate to growth and behavior in a Japanese preschool cohort.

Early childhood is a period of rapid brain maturation and gut microbiome assembly, when emerging behavioral difficulties can shape later mental health and learning trajectories. Microbiota-gut-brain communication has been implicated in neurodevelopment through microbial metabolites and immune signaling. However, most pediatric evidence comes from high-risk or clinically referred cohorts, and gut microbiome-related correlates of typical behavioral variation in community-based preschool children remain poorly defined. In a cross-sectional sample of typically developing Japanese preschool children, we observed exploratory nominal associations between behavioral variation within normative ranges and gut microbiome composition and predicted functions. Internalizing domains showed candidate links with taxa and predicted pathways related to inflammatory potential and nucleotide biosynthesis, whereas somatic complaints and withdrawn behavior showed nominal associations with lower predicted respiratory and fermentative activity. Sleep-related difficulties showed multiple representative nominal pathway-level associations, including pathways related to methyl-donor and heme biosynthesis, while externalizing domains showed candidate links with predicted cell-envelope and carbohydrate-remodeling pathways. In contrast, age, height, and weight tracked expected maturation-related microbiome features, indicating that behavioral associations were not simple proxies of growth. Together, these findings provide an exploratory profile of microbiome-behavior correlations in a low-risk Japanese preschool cohort and highlight pathway-level candidates that may interface with neurodevelopment.

Humans↗

PubMed2006

Culture-independent analysis of the microbial composition of the African traditional fermented foods poto poto and dégué by using three different DNA extraction methods.

The microbial composition of the traditional fermented foods poto poto (a maize dough from the Rep. of Congo) and dégué (a millet dough from Burkina Faso) was studied by a culture-independent approach using TTGE to separate the amplified target V3 region of the 16S rRNA gene from total microbial community, followed by DNA sequencing and homology search. Three different extraction methods were used. Guanidium thiocyanate-based DNA extraction provided better performance regarding purity and DNA yield, allowing the detection of a higher number of DNA bands by TTGE in poto poto. By contrast, all three methods yielded similar results for dégué samples, indicating that the performance of the DNA extraction method largely depends on the food composition. Sequencing of DNA bands from TTGE gels corresponding to poto poto samples revealed the presence of Lactobacillus gasseri, Enterococcus sp., Escherichia coli, Lactobacillus plantarum/paraplantarum, Lactobacillus acidophilus, Lactobacillus delbrueckii, Bacillus sp., Lactobacillus reuteri and Lactobacillus casei. The following bacteria were identified in dégué: L. gasseri, Enterococcus sp., E. coli, Lactobacillus fermentum, Lactobacillus brevis, and L. casei.

Bacillus↗

PubMed2006

Microbial community structure in polluted Baltic Sea sediments.

Nearly half the seabed of the Baltic Proper is incapable of supporting life of higher organisms as a consequence of oxygen depletion resulting from eutrophication. However, these areas are actually teeming with microbial life. Here we used terminal-restriction fragment length polymorphism (T-RFLP) to investigate the dominant archaeal and bacterial groups, with respect to community structure, in surface layers of bottom sediments of the Baltic Sea along a coastal pollution gradient. Both archaeal and bacterial communities formed distinct clusters along the pollution gradient and the community compositions were different at the polluted sites compared with the relatively clean reference sites. The structures of the bacterial communities were most strongly correlated to water depth, followed by organic carbon, oxygen, salinity and silicate levels. In contrast, the structures of the archaeal communities were most strongly correlated to oxygen, salinity, organic carbon, silicate and nitrate levels. Some members of the microbial communities were identified using a combination of traditional and molecular approaches. Isolates obtained on different culture media were identified by partial sequencing of their 16S rRNA genes and some novel species were found. In addition, we developed a computer program, aplaus, to elucidate the putative identities of the most dominant community members by T-RFLP.

Bacteria↗

PubMed2005

Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest.

Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems.

Ascomycota↗

PubMed2005

Effect of wastewater composition on archaeal population diversity.

Distribution and occurrence of Archaea and methanogenic activity in a laboratory scale, completely mixed anaerobic reactor treating pharmaceutical wastewaters were investigated and associated with reactor performance. The reactor was initially seeded with anaerobic digester sludge from an alcohol distillery wastewater treatment plant and was subjected to a three step feeding strategy. The feeding procedure involved gradual transition from a glucose containing feed to a solvent stripped pharmaceutical wastewater and then raw pharmaceutical wastewater. During the start-up period, over 90% COD removal efficiency at an organic loading rate (OLR) of 6 kg COD m(-3)d(-1) was achieved with glucose feeding, and acetoclastic methanogenic activity was 336 ml CH4 gTVS(-1)d(-1). At the end of the primary loading, when the feed contained solvent stripped pharmaceutical wastewater at full composition, 71% soluble COD removal efficiency was obtained and acetoclastic methanogenic activity decreased to half of the rate under glucose feed (166 ml CH4 gTVS(-1)d(-1)). At the end of secondary loading with 60% (w/v) raw pharmaceutical wastewater, COD removal dropped to zero and acetoclastic methanogenic activity fell to less than 10 ml CH4 gTVS(-1)d(-1). Throughout the course of the experiment, microbial community structure was monitored by DGGE analysis of 16S rRNA gene fragments. Five different archaeal taxa were identified and the predominant archaeal sequences belonged to methanogenic Archaea. Two of these showed greatest sequence identity with Methanobacterium formicicum and Methanosaeta concilii. The types of Archaea present changed little in response to changing feed composition but the relative contribution of different organisms identified in the archaeal DGGE profiles did change.

Archaea↗

PubMed2026

Brucellar spondylitis is associated with disturbance in gut microbiota and histamine metabolism associated inflammation.

BACKGROUND: The pathogenesis of brucellar spondylitis (BLS) has traditionally been considered to be primarily limited to local osteoarticular lesions. With the proposal of the "gut-spine axis" concept, the role of intestinal microecological dysbiosis in inflammatory spinal diseases has attracted in an increase of attention. The overactivated inflammatory cytokine network not only mediates bone destruction and intervertebral disc damage, but also forms a bidirectional interaction with gut microbiota dysbiosis through the "gut-spine axis," collectively driving disease progression. However, the inflammatory mechanism by which gut microbiota participates in the pathological process of BLS remains largely unclear. METHODS: This study recruited 20 BLS patients and 20 healthy donors. Multi-omics analysis including metagenomics, untargeted metabolomics, and targeted short-chain fatty acids (SCFAs) analysis, were used to compare the structural differences in gut microbiota between the two groups and screen for signature differential bacterial species. Plasma levels of histamine and histidine decarboxylase were measured by ELISA to clarify the role of differential histidine metabolic pathway in the disease. Additionally, plasma levels of lipopolysaccharide (LPS) and inflammatory cytokines (IL-1β, IL-6, IL-10, IL-17A, TNF-α) were detected by ELISA. The correlation between gut microbiota and inflammatory indicators was further analyzed. RESULTS: Compared to the healthy control group, the α-diversity of the gut microbiota in BLS patients was significantly reduced, with the microbial community structure exhibiting increased homogeneity. Beta diversity analysis revealed significant differences, suggesting that disease progression is associated with an overall imbalance in the gut microbiota and the deterioration of its specific structural composition. At the phylum level, the abundances of Actinomycetota, unclassified_d_Viruses, and Fusobacteriota were significantly increased in the gut microbiota of BLS patients compared to the control group, while the abundances of Bacillota and Pseudomonadota were significantly decreased. Further analysis revealed that, compared to the control group, the generic abundance of Enterococcus was significantly increased, while the proportions of Blautia, Faecalibacterium, Ruminococcus, Agathobacter, Roseburia, Clostridium, Eubacterium, Alistipes and Anaerobutyricum were significantly decreased. At the species level, the abundances of Enterococcus sp and Enterococcus-faecium were increased, whereas Blautia sp, Ruminococcus sp, Faecalibacterium sp, Faecalibacterium prausnitzii, Agathobacter rectalis, Eubacterium sp, Agathobacter sp, and Roseburia sp were decreased. Furthermore, untargeted metabolomics revealed that metabolites were enriched in the histidine metabolic pathway, and the levels of SCFAs including butyrate, isobutyrate, valerate, and 4-methylvalerate in the intestinal contents were reduced in BLS. Functional KEGG profiling revealed that key KOs involved in butyrate synthesis (e.g., K00074, K00172, K01640) and transport were globally downregulated in the patient group, whereas histidine decarboxylase KOs (K01693, K11755, K19787) that convert histidine to pro-inflammatory histamine were significantly enriched. The loss of butyrate-producing symbionts led to SCFAs deficiency and mucosal barrier disruption, creating ecological niches for facultatively anaerobic Enterococcus, which further exacerbated local inflammation via proteolytic fermentation and histamine production. Compared with the control group, BLS patients showed decreased plasma levels of IL-10, while levels of IL-1β, IL-6, IL-17A, and TNF-α were increased, and LPS levels were elevated. In addition, significantly elevated plasma pro-inflammatory LPS levels in patients with BLS suggest disruption of intestinal integrity and permeability. Correlation analysis indicated a close relationship between gut microbiota and inflammation. CONCLUSION: BLS is associated with gut microbiota dysbiosis and alterations in microbial metabolites, which may be linked to inflammatory responses and histamine metabolism. The differential microbial taxa identified in this study could be developed into a stool-based non-invasive diagnostic panel to facilitate early differentiation of BLS from other spinal disorders. Furthermore, restoring gut microbial balance through probiotic supplementation or dietary modulation may represent a promising adjunctive strategy to enhance the efficacy of standard antibiotic therapy and reduce disease recurrence.

Humans↗

PubMed2026

Metagenomic insights into biogeochemical functional potential and resistome dynamics of PM2.5 microbial communities.

Atmospheric particulate matter harbors diverse microorganisms, yet their functional potential in biogeochemical cycling and the associated risks of resistome remain poorly understood. Here, we performed metagenomic sequencing on PM2.5 samples collected across four months to unravel the microbial genetic repertoire involved in methane, nitrogen, phosphorus, and sulfur cycling, as well as the resistome, and pathogen composition. A broad range of functional genes was detected for each biogeochemical cycle, with more than 65% of gene subtypes shared across all months, indicating conserved functional signatures. In contrast, more than 80% of the resistome showed temporal variation in abundance, with the lowest richness observed in March. Temporal shifts were also observed in resistome composition, with several resistance determinants reaching higher abundances in April and May. Network analysis indicated frequent co-occurrence among several pathogenic and opportunistic taxa. Contig-based profiling identified 51 potential pathogenic taxa, including 32 human- or animal-associated taxa. In addition, both PM10 and PM2.5 concentrations were associated with pathogen abundance and functional gene richness (e.g., antibiotic resistance genes and virulence factors). Together, this metagenomic survey suggests contrasting temporal patterns between conserved biogeochemical functional potential and more variable resistome-related traits in PM2.5 microbial communities. While constrained by limited temporal coverage and sample size, this study provides preliminary insights into the ecological and potential public health relevance of airborne microbial communities in urban environments.

Particulate Matter↗

PubMed1995

Highly active microbial communities in the ice and snow cover of high mountain lakes.

An exploratory study carried out in Pyrenean and Alpine lakes shows that a rich, active microbial community lives in the slush layers of the winter cover of such lakes in spite of the low temperature and the seasonal occurrence of the habitat. Bacteria were very diverse in morphology, with filaments reaching up to 100 (mu)m long; flagellates, both autotrophic (chrysophytes, cryptophytes, dinoflagellates, and volvocales) and heterotrophic, and ciliates were abundant, reaching biovolume values up to 2.7 x 10(sup6) (mu)m(sup3) ml(sup-1). Species composition was very variable, with dominance depending on date and depth. Although many species were typical of lake plankton communities, some were restricted to the slush, for instance the predatory ciliates Dileptus sp. and Lacrymaria sp., and others were restricted to the surface pools, such as the snow algae Chlamydomonas nivalis. Microbial biomasses and usually bacterial and algal activities were greater in the slush layers than in the lake water. Photosynthesis rate in the upper cover layers reached values up to 0.5 (mu)g of C liter(sup-1) h(sup-1), and high bacterial activities up to 226 pmol of leucine incorporated liter(sup-1) h(sup-1) and 25 pmol of thymidine incorporated liter(sup-1) h(sup-1) were measured. For most species, lake water flooding the ice and snow cover could provide an inoculum. Differential growth depending on the environmental conditions (nutrients, organic matter, light) of a particular slush layer could provide dominance of different groups or species. However, there was no obvious colonizing mechanism for those species not appearing either in plankton or in communities on top of the snowpack.

Journal Article↗

PubMed2025

A global survey of taxa-metabolic associations across mouse microbiome communities.

Host-microbiota mutualism is rooted in the exchange of dietary and metabolic molecules. Microbial diversity broadens the metabolite pool, with each taxon contributing distinct compounds in varying proportions. In the human microbiome, high variability in consortial composition is largely compensated by similar metabolic functions across different taxa. However, the extent of compensation in lower diversity mouse models, and whether vivaria are metabolically equivalent, is unknown. We provide a searchable resource of microbiome composition variability across 51 murine vivaria and 12 wild mouse colonies worldwide, with vivarium-specific variants mapped according to predicted 3D structures for each microbial species. Our matched metabolomics data show that realized metabolic potential has relatively low variability, providing functional evidence for metabolic compensation. Additionally, variability is related to taxonomic composition rather than vivarium, revealing taxa-metabolite associations that are potentially relevant to phenotypic differences between vivaria. Collectively, this resource offers tools to strengthen microbiome studies and collaborative science.

Animals↗

PubMed2006

Environmental controls on denitrifying communities and denitrification rates: insights from molecular methods.

The advent of molecular techniques has improved our understanding of the microbial communities responsible for denitrification and is beginning to address their role in controlling denitrification processes. There is a large diversity of bacteria, archaea, and fungi capable of denitrification, and their community composition is structured by long-term environmental drivers. The range of temperature and moisture conditions, substrate availability, competition, and disturbances have long-lasting legacies on denitrifier community structure. These communities may differ in physiology, environmental tolerances to pH and O2, growth rate, and enzyme kinetics. Although factors such as O2, pH, C availability, and NO3- pools affect instantaneous rates, these drivers act through the biotic community. This review summarizes the results of molecular investigations of denitrifier communities in natural environments and provides a framework for developing future research for addressing connections between denitrifier community structure and function.

DNA, Archaeal↗

PubMed2026

Decoding microbial metabolic complementarity from individual traits to community structuring.

A fundamental challenge in microbiome research lies in elucidating the functional capacity of microbial communities through community membership and genomic data. As community structuring and emergent functional traits are determined by bacterial community metabolic networks, it is important to gain insights into the principles that govern bacteria-bacteria interactions. Here, we applied an integrative framework linking individual strain-level traits to community structuring in a simplified synthetic bacterial community (SSC8) that promotes the growth of ungrafted watermelon. By combining mono- and coculture assays with genome-scale metabolic modeling and metabolomic profiling of spent media, we characterized directional interactions and resource dependencies among community members. Our findings show that positive interactions dominated the community network, accounting for 55% of all pairwise combinations, indicating a high prevalence of growth-promoting effects among strains. Genome-scale metabolic modeling showed that functional divergence among strains enhanced the potential for metabolic complementarity as phylogenetic distance increased. Integrating metabolic modeling with metabolomics further suggested that Pseudomonas azotifigens Q6 not only benefited from all other community members, but also exhibited mutualistic interactions with the other three strains, with metabolite exchange involving compounds such as L-lysine and L-cysteine. Pseudomonas azotifigens Q6 acted as an important driver of community composition by affecting the abundance of several other consortium members in vitro. These findings highlight the role of metabolic complementarity in driving community structuring by promoting selective persistence of specific strains. Our work provides mechanistic insights into microbial interaction networks in vitro and offers a conceptual foundation for the rational design of functionally robust and plant-beneficial microbiomes.

Bacteria↗

PubMed1977

Acute respiratory illness in the community: effect of family composition, smoking, and chronic symptoms.

Respiratory illness and infection was studied in the community of Tecumseh, Michigan, USA, during a six-year period. Acute illness was ascertained by making weekly telephone calls, and prevalent agents were identified by microbial isolation. Infection rates were determined serologically using blood specimens collected routinely at six monthly intervals from those reported to be ill. Illness rates were higher in the youngest children of families up to the age of three years than for the oldest children of the same ages. Above the age of three, the pattern was reversed. Among the adults, rates of illness were shown to relate not only to the presence, but also to the age of children in the home. Throughout this comparison, women were more likely to be ill than men in the same groups. Smoking in itself was not related to increased acute respiratory illnesses, but persons with symptoms of chronic bronchitis were found to have higher illness rates independently of whether they smoked.

Adolescent↗

PubMed2001

Effects of community composition and growth rate on aquifer biofilm bacteria and their susceptibility to betadine disinfection.

Biofilm formation and function was studied in mixed culture using 20 bacterial strains isolated from a karst aquifer. When co-cultured in a glucose-limited chemostat, Vogesella indigofera and Pseudomonas putida were the dominant planktonic and biofilm organisms respectively. Biofilm formation and resistance to the iodine disinfectant betadine were then studied with monoculture and binary cultures of V. indigofera and P. putida and a 20-strain community. Biofilm population size [measured as colony-forming units (CFU) cm(-2)] increased with increasing species diversity. Significantly larger populations formed at dilution rates (DRs) of 0.0083 h(-1) than at 0.033 h(-1). P. putida populations were higher and V. indigofera lower in binary than in monoculture biofilms, suggesting that P. putida outcompeted V. indigofera. In binary biofilms, V. indigofera, a betadine-resistant organism, enhanced the survival of P. putida, a betadine-susceptible organism. In the 20-strain biofilms, this protective effect was not observed because of low concentrations of V. indigofera (< 1% of the total population), suggesting that resistant organisms contribute to overall biofilm disinfectant resistance. Growth at 0.033 h(-1) enhanced survival of V. indigofera biofilms against betadine. Although DR did influence survival of the other communities, its effects were neither consistent nor significant. All told, biofilm formation and betadine resistance are complex phenomena, influenced by community composition, growth rate and betadine concentration.

Bacteriological Techniques↗

PubMed2006

Urban aerosols harbor diverse and dynamic bacterial populations.

Considering the importance of its potential implications for human health, agricultural productivity, and ecosystem stability, surprisingly little is known regarding the composition or dynamics of the atmosphere's microbial inhabitants. Using a custom high-density DNA microarray, we detected and monitored bacterial populations in two U.S. cities over 17 weeks. These urban aerosols contained at least 1,800 diverse bacterial types, a richness approaching that of some soil bacterial communities. We also reveal the consistent presence of bacterial families with pathogenic members including environmental relatives of select agents of bioterrorism significance. Finally, using multivariate regression techniques, we demonstrate that temporal and meteorological influences can be stronger factors than location in shaping the biological composition of the air we breathe.

Aerosols↗