[Show abstract][Hide abstract] ABSTRACT: Microorganisms play critical roles in many important biogeochemical processes in the Earth's biosphere. However, understanding and characterizing the functional capacity of microbial communities is still difficult due to the extremely diverse and often uncultivable nature of most microorganisms. In this study, we developed a new functional gene array, GeoChip 4, for analyzing the functional diversity, composition, structure, metabolic potential/activity, and dynamics of microbial communities. GeoChip 4 contained approximately 82,000 probes covering 141,995 coding sequences from 410 functional gene families related to microbial carbon (C), nitrogen (N), sulfur (S), and phosphorus (P) cycling, energy metabolism, antibiotic resistance, metal resistance/reduction, organic remediation, stress responses, bacteriophage, and virulence. A total of 173 archaeal, 4,138 bacterial, 404 eukaryotic and 252 viral strains were targeted, providing the ability to analyze targeted functional gene families of microorganisms included in all four domains. Experimental assessment using different amounts of DNA suggested that as little as 500 ng environmental DNA was required for good hybridization, and the signal intensities detected were well correlated with the DNA amount used. GeoChip 4 was then applied to study the effect of long-term warming on soil microbial communities at a Central Oklahoma site, with results indicating that microbial communities respond to long-term warming by enriching carbon-degradation, nutrient-cycling (nitrogen and phosphorous), and stress response gene families. To the best of our knowledge, GeoChip 4 is the most comprehensive functional gene array for microbial community analysis. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Pathogens present in the environment pose a serious threat to human, plant and animal health as evidenced by recent outbreaks. As many pathogens can survive and proliferate in the environment, it is important to understand their population dynamics and pathogenic potential in the environment. To assess pathogenic potential in diverse habitats, we developed a functional gene array, the PathoChip, constructed with key virulence genes related to major virulence factors, such as adherence, colonization, motility, invasion, toxin, immune evasion and iron uptake. A total of 3715 best probes were selected from 13 virulence factors, covering 7417 coding sequences from 1397 microbial species (2336 strains). The specificity of the PathoChip was computationally verified, and approximately 98% of the probes provided specificity at or below the species level, proving its excellent capability for the detection of target sequences with high discrimination power. We applied this array to community samples from soil, seawater and human saliva to assess the occurrence of virulence genes in natural environments. Both the abundance and diversity of virulence genes increased in stressed conditions compared with their corresponding controls, indicating a possible increase in abundance of pathogenic bacteria under environmental perturbations such as warming or oil spills. Statistical analyses showed that microbial communities harboring virulence genes were responsive to environmental perturbations, which drove changes in abundance and distribution of virulence genes. The PathoChip provides a useful tool to identify virulence genes in microbial populations, examine the dynamics of virulence genes in response to environmental perturbations and determine the pathogenic potential of microbial communities.The ISME Journal advance online publication, 13 June 2013; doi:10.1038/ismej.2013.88.
The ISME Journal 06/2013; 7(10). DOI:10.1038/ismej.2013.88 · 9.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Deepwater Horizon oil spill in the Gulf of Mexico is the deepest and largest offshore spill in the United State history and its impacts on marine ecosystems are largely unknown. Here, we showed that the microbial community functional composition and structure were dramatically altered in a deep-sea oil plume resulting from the spill. A variety of metabolic genes involved in both aerobic and anaerobic hydrocarbon degradation were highly enriched in the plume compared with outside the plume, indicating a great potential for intrinsic bioremediation or natural attenuation in the deep sea. Various other microbial functional genes that are relevant to carbon, nitrogen, phosphorus, sulfur and iron cycling, metal resistance and bacteriophage replication were also enriched in the plume. Together, these results suggest that the indigenous marine microbial communities could have a significant role in biodegradation of oil spills in deep-sea environments.
The ISME Journal 08/2011; 6(2):451-60. DOI:10.1038/ismej.2011.91 · 9.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Modern methods to develop microbe-based biomass conversion processes require a system-level understanding of the microbes
involved. Clostridium species have long been recognized as ideal candidates for processes involving biomass conversion and
production of various biofuels and other industrial products. To expand the knowledge base for clostridial species relevant
to current biofuel production efforts, we have sequenced the genomes of 20 species spanning multiple genera. The majority
of species sequenced fall within the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Species were chosen based on representation in the experimental literature as model organisms, ability to degrade cellulosic
biomass either by free enzymes or by cellulosomes, ability to rapidly ferment hexose and pentose sugars to ethanol, and ability
to ferment synthesis gas to ethanol. The sequenced strains significantly increase the number of noncommensal/nonpathogenic
clostridial species and provide a key foundation for future studies of biomass conversion, cellulosome composition, and clostridial
Journal of bacteriology 10/2010; 192(24):6494-6. DOI:10.1128/JB.01064-10 · 2.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Strain JW/YJL-B18(T), a spore-forming, sulfate-reducing bacterium, was isolated from constructed wetland sediment. Cells were curved rods, 0.7-1.2 mum in diameter and 3-7 mum long. Despite being phylogenetically a member of the Gram-type-positive phylum Firmicutes, cells stained Gram-negative at all growth phases. Strain JW/YJL-B18(T) grew at 8-39 degrees C, with an optimum at 32-35 degrees C and no growth at 4 degrees C or below or at 42 degrees C or above. The pH(25 degrees C) range for growth was 5.7-8.2, with an optimum at pH(25 degrees C) 7.0-7.3, and no growth was detected at or below pH 5.2 or at or above pH 8.4. The salinity range for growth was 0-3 % (NaCl/KCl 9 : 1). Strain JW/YJL-B18(T) utilized as carbon and energy sources beef extract, yeast extract, formate, succinate, lactate, pyruvate, ethanol and toluene. Fumarate, sulfate, sulfite and thiosulfate were reduced in the presence of lactate. Arsenate (V) was not used as an electron acceptor. Strain JW/YJL-B18(T) showed no indication of growth under autotrophic conditions. The predominant cellular fatty acids were C(16 : 1) and C(16 : 0). The genomic DNA G+C content was 36.6 mol% (HPLC). 16S rRNA gene sequence analysis indicated that strain JW/YJL-B18(T) fell into the genus Desulfosporosinus, with Desulfosporosinus auripigmenti OREX-4(T) as its closest neighbour with a validly published name (97.9 % similarity). Based on molecular genetic evidence and physiological and biochemical characters including differences in the DNA G+C content, we propose to place strain JW/YJL-B18(T) (=DSM 17734(T) =ATCC BAA-1261(T)) as the type strain of a novel species, Desulfosporosinus youngiae sp. nov.
International Journal of Systematic and Evolutionary Microbiology 08/2009; 59(Pt 11):2743-6. DOI:10.1099/ijs.0.007336-0 · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An obligately anaerobic, spore-forming, Gram-type-positive but Gram-staining-negative thermophilic bacterium, strain JW/YJL-F3(T), was isolated from a Fijian hot spring sediment sample. Cells of strain JW/YJL-F3(T) were straight to slightly curved rods, 0.5-1.2 microm in diameter and 1.5-19 microm long. The temperature range for growth was between 40 and 67 degrees C, with an optimum at 60-63 degrees C. The pH(25 degrees C) range for growth was 4.5-8.4 with an optimum of 6.8. The salinity range for growth was 0-0.5 %. Strain JW/YJL-F3(T) utilized a range of substrates including arabinose, cellobiose, galactose, glucose, inulin, lactose, maltose, mannose, raffinose, ribose, trehalose, xylose and yeast extract as carbon and energy sources. The major fermentation end products from glucose were ethanol, acetate and formate. Strain JW/YJL-F3(T) converted thiosulfate to elemental sulfur, producing sulfur globules. The DNA G+C content was 37.6 mol% as determined by HPLC. Phylogenetic analysis using the 16S rRNA gene sequence indicated that the isolate is distantly related to the clade of the genus Thermoanaerobacterium. However, Thermoanaerobacterium polysaccharolyticum (96.7 % similarity to the type strain) and Thermoanaerobacterium zeae were the closest relatives, forming a separate, well-supported clade together with the novel isolate. Because Thermoanaerobacterium polysaccharolyticum, Thermoanaerobacterium zeae and strain JW/YJL-F3(T) have different features from other Thermoanaerobacterium species, including a higher G+C content and formate production, and are placed distantly from the remaining species of Thermoanaerobacterium (greater than 10 % distance) in the 16S rRNA gene sequence analysis, we propose to place the new isolate JW/YJL-F3(T) and Thermoanaerobacterium polysaccharolyticum and Thermoanaerobacterium zeae into the novel genus Caldanaerobius gen. nov. as Caldanaerobius fijiensis gen. nov., sp. nov. (the type species), Caldanaerobius polysaccharolyticus comb. nov. and Caldanaerobius zeae comb. nov., respectively. The type strain of Caldanaerobius fijiensis is JW/YJL-F3(T) (=ATCC BAA-1278(T) =DSM 17918(T)).
International Journal of Systematic and Evolutionary Microbiology 04/2008; 58(Pt 3):666-70. DOI:10.1099/ijs.0.65329-0 · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Two anaerobic thermophilic bacteria, designated strains JW/SL824 and JW/SL-NZ826(T), were isolated from an acidic volcanic steam outlet on White Island, New Zealand. Cells were rod-shaped, spore-forming, motile and Gram-stain negative, but contained Gram-type positive cell wall. Strain JW/SL-NZ826(T) utilized various carbohydrates including xylose and glucose. The fermentation end products produced from glucose in the absence of thiosulfate were lactate, ethanol, acetate, CO(2) and H(2). The temperature range for growth was 34-72 degrees C, with an optimum at 63-67 degrees C. The pH(60 degrees C) range for growth was 4.0-8.0, with an optimum at 5.0-6.5. The doubling time of strain JW/SL-NZ826(T) under optimal growth conditions was 2.4 h. The DNA G+C content was 34-35 mol% (HPLC). The two strains reduced up to 1 M thiosulfate to elemental sulfur without sulfide formation, which is a trend typically observed among species belonging to the genus Thermoanaerobacterium. Sulfur globules containing short and long sulfur chains but no S(8)-ring sulfur were produced inside and outside the cells. Up to 90 mM sulfite was tolerated. This tolerance is assumed to be an adaptation to the geochemistry of the environment of White Island. The 16S rRNA gene sequence analysis, however, indicated that the two strains belonged to the genus Thermoanaerobacter, with similarities in the range 95.6-92.7 %. Therefore, strains JW/SL-NZ824 and JW/SL-NZ826(T) represent a novel taxon, for which the name Thermoanaerobacter sulfurigignens sp. nov. is proposed, with strain JW/SL-NZ826(T) (=ATCC 700320(T)=DSM 17917(T)) as the type strain. Based on this and previous studies, an emended description of the genus Thermoanaerobacter is given.
International Journal of Systematic and Evolutionary Microbiology 08/2007; 57(Pt 7):1429-34. DOI:10.1099/ijs.0.64748-0 · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An obligately anaerobic, spore-forming, moderately acid-tolerant bacterium, strain JW/YJL-B3T, was isolated from a sediment sample from a constructed wetland system receiving acid sulfate water. Based on 16S rRNA gene sequence analysis, the isolate belonged to the Firmicutes branch with Clostridium drakei SL1T (96.2 % gene sequence similarity) as its closest relative. The G+C content of the genomic DNA was 30.8 mol% (HPLC). Cells were straight to curved rods, 0.5-1.0 microm in diameter and 3.0-9.0 microm in length. The temperature range for growth was 20-45 degrees C, with an optimum around 35 degrees C. Growth was not detected below 18 degrees C or above 47 degrees C. The pH range for growth was broad, pH(25 degrees C) 3.8-8.9, with an optimum at 7.0-7.5. However at pH 4.5, the strain grew at 52 % of the optimal growth rate. The salinity range was 0-1.5 % NaCl (w/v). Strain JW/YJL-B3T utilized beef extract, Casamino acids, peptone, tryptone, arabinose, cellobiose, fructose, galactose, glucose, lactose, maltose, mannose, raffinose, ribose, sucrose, xylose, pyruvate, glutamate and inulin as a carbon and energy source. There were no indications of growth under aerobic or autotrophic conditions. The isolate produced acetate, butyrate and ethanol as fermentation end products from glucose. Based on these characteristics and other physiological properties, the isolate is placed into the novel taxon, Clostridium aciditolerans sp. nov., with strain JW/YJL-B3T (=DSM 17425T=ATCC BAA-1220T) as the type strain.
International Journal of Systematic and Evolutionary Microbiology 03/2007; 57(Pt 2):311-5. DOI:10.1099/ijs.0.64583-0 · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An obligatorily anaerobic, thermotolerant, asporogenic bacterium, strain JW/YJL-S1(T), was isolated from a sediment sample of a constructed wetland system receiving acid sulfate water (pH 1.6-3.0). Cells of strain JW/YJL-S1(T) were straight to curved rods 0.2-0.4 mum in diameter and 2.0-7.0 mum in length, and stained Gram-negative. Growth of strain JW/YJL-S1(T) was observed at 25-54 degrees C (no growth at or below 20 or at or above 58 degrees C), with an optimum temperature range for growth of 42.5-46.5 degrees C. The pH(25 degrees C) range for growth was 6.0-8.25 (no growth at or below pH 5.7 or at or above pH 8.5), with optimum growth at pH 6.8-7.75. The salinity range for growth was 0-1.5 % (w/v) NaCl, with an optimum at 0-0.5 %. During growth on glucose the isolate produced acetate, lactate and ethanol as main fermentation end products. The fatty acid composition was dominated by branched-chain compounds: i15 : 0, a15 : 0, i16 : 0 and i17 : 0. The G+C content of the genomic DNA was 42.8 mol% (HPLC). Strain JW/YJL-S1(T) showed polymorphism of the 16S rRNA gene. Its closest relative was the thermophilic Clostridium thermosuccinogenes DSM 5807(T) (a member of Clostridium cluster III) (a blastn search revealed Clostridium pascui DSM 10365(T) to have 92.7 % gene sequence similarity, the highest value). The inferred phylogenetic trees placed strain JW/YJL-S1(T) between Clostridium clusters I/II and III. Based on the morphological and phylogenetic data presented, JW/YJL-S1(T) (=DSM 17427(T)=ATCC BAA-1219(T)) is proposed as the type strain of a novel species in a new genus, Gracilibacter thermotolerans gen. nov., sp. nov.
International Journal of Systematic and Evolutionary Microbiology 10/2006; 56(Pt 9):2089-93. · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although the type species of the genus Thermoanaerobium, Thermoanaerobium brockii, was transferred to Thermoanaerobacter, Thermoanaerobium acetigenum was not transferred. Therefore, Thermoanaerobium acetigenum should be reclassified. Based on 16S rRNA gene sequence analysis and re-examination of physiological properties of the type strain, X6B(T) (=DSM 7040(T) = ATCC BAA-1149(T)), we propose that Thermoanaerobium acetigenum should be reclassified as Caldicellulosiruptor acetigenus comb. nov. Strain X6B(T) contains two separate 16S rRNA genes bracketing another species in the phylogenetic 16S rRNA gene-based tree.
International Journal of Systematic and Evolutionary Microbiology 07/2006; 56(Pt 6):1391-5. DOI:10.1099/ijs.0.63723-0 · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A new group of anaerobic thermophilic bacteria was isolated from enrichment cultures obtained from deep sea sediments of Peru Margin collected during Leg 201 of the Ocean Drilling Program. A total of ten isolates were obtained from cores of 1-2 m below seafloor (mbsf) incubated at 60°C: three isolates came from the sediment 426 m below sea level with a surface temperature of 9°C (Site 1227), one from 252 m below sea level with a temperature of 12°C (Site 1228), and six isolates under sulfate-reducing condition from the lower slope of the Peru Trench (Site 1230). Strain JW/IW-1228P from the Site 1228 and strain JW/YJL-1230-7/2 from the Site 1230 were chosen as representatives of the two identified clades. Based on the 16S rDNA sequence analysis, these isolates represent a novel group with Thermovenabulum and Caldanaerobacter as their closest relatives. The temperature range for growth was 52-76°C with an optimum at around 68°C for JW/IW-1228P and 43-76°C with an optimum at around 64°C for JW/YJL-1230-7/2. The pH25C range for growth was from 6.3 to 9.3 with an optimum at 7.5 for JW/IW-1228P and from 5 to 9.5 with an optimum at 7.9-8.4 for JW/YJL-1230-7/2. The salinity range for growth was from 0% to 6% (w/v) for JW/IW-1228P and from 0% to 4.5% (w/v) for JW/YJL-1230-7/2. The G+C content of the DNA was 50 mol% for both JW/IW-1228P and JW/YJL-1230-7/2. DNA-DNA hybridization yielded 52% similarity between the two strains. According to 16S rRNA gene sequence analysis, the isolates are located within the family, Thermoanaerobacteriaceae. Based on their morphological and physiological properties and phylogenetic analysis, it is proposed that strain JW/IW-1228PT is placed into a novel taxa, Thermosediminibacter oceani, gen. nov., sp. nov. (DSM 16646T=ATCC BAA-1034T), and JW/YJL-1230-7/2T into Thermosediminibacter litoriperuensis sp. nov. (DSM 16647T =ATCC BAA-1035T).