Qiang He - Academia.edu (original) (raw)

Papers by Qiang He

Sulphate-reducing microorganisms (SRMs) are a phylogenetically diverse group of anaerobes encompa... more Sulphate-reducing microorganisms (SRMs) are a phylogenetically diverse group of anaerobes encompassing distinct physiologies with a broad ecological distribution. As SRMs have important roles in the biogeochemical cycling of carbon, nitrogen, sulphur and various metals, an understanding of how these organisms respond to environmental stresses is of fundamental and practical importance. In this Review, we highlight recent applications of systems biology tools in studying the stress responses of SRMs, particularly Desulfovibrio spp., at the cell, population, community and ecosystem levels. The syntrophic lifestyle of SRMs is also discussed, with a focus on system-level analyses of adaptive mechanisms. Such information is important for understanding the microbiology of the global sulphur cycle and for developing biotechnological applications of SRMs for environmental remediation, energy production, biocorrosion control, wastewater treatment and mineral recovery.

Ultrasonics sonochemistry, 2018

This study investigated sulfamethazine (SMT) ultrasound degradation, enhanced by iodine radicals,... more This study investigated sulfamethazine (SMT) ultrasound degradation, enhanced by iodine radicals, generated by potassium iodide (KI) and hydrogen peroxide (HO) in situ. The results showed that the ultrasound/HO/KI (US/HO/KI) combination treatment achieved an 85.10 ± 0.45% SMT removal (%) in 60 min under the following conditions: pH = 3.2, ultrasound power of 195 W, initial SMT concentration of 0.04 mmol·L, HO concentration of 120 mmol·L, and KI concentration of 2.4 mmol·L. UV-Vis spectrophotometric monitoring of molecular iodine (I) and triiodide (I) revealed a correlation between the SMT degradation and the iodine change in the solution. Quenching experiments using methanol, t-butanol and thiamazole as radical scavengers indicated that iodine radicals, such as I and I, were more important than hydroxyl radicals (HO) for SMT degradation. SMT degradation under the US/HO/KI treatment followed pseudo-first order reaction kinetics. The activation energy (E) of SMT degradation was 7.75 ±...

The ISME journal, Dec 25, 2017

The ecological concept of the r-K life history strategy is widely applied in macro-ecology to cha... more The ecological concept of the r-K life history strategy is widely applied in macro-ecology to characterize functional traits of taxa. However, its adoption in microbial communities is limited, owing to the lack of a measureable, convenient functional trait for classification. In this study, we performed an experiment of stepwise organic amendments in triplicate anaerobic digesters. We found that high resource availability significantly favored microbial r-strategists such as Bacillus spp. Incremental resource availability heightened average rRNA operon copy number of microbial community, resulting in a strong, positive correlation (r>0.74, P<0.008). This study quantifies how resource availability manipulations influence microbial community composition and supports the idea that rRNA operon copy number is an ecologically meaningful trait which reflects resource availability.The ISME Journal advance online publication, 25 August 2017; doi:10.1038/ismej.2017.135.

Frontiers in Microbiology, 2016

Acidithiobacillus caldus is an extremely acidophilic sulfur-oxidizer with specialized characteris... more Acidithiobacillus caldus is an extremely acidophilic sulfur-oxidizer with specialized characteristics, such as tolerance to low pH and heavy metal resistance. To gain novel insights into its genetic complexity, we chosen six A. caldus strains for comparative survey. All strains analyzed in this study differ in geographic origins as well as in ecological preferences. Based on phylogenomic analysis, we clustered the six A. caldus strains isolated from various ecological niches into two groups: group 1 strains with smaller genomes and group 2 strains with larger genomes. We found no obvious intraspecific divergence with respect to predicted genes that are related to central metabolism and stress management strategies between these two groups. Although numerous highly homogeneous genes were observed, high genetic diversity was also detected. Preliminary inspection provided a first glimpse of the potential correlation between intraspecific diversity at the genome level and environmental variation, especially geochemical conditions. Evolutionary genetic analyses further showed evidence that the difference in environmental conditions might be a crucial factor to drive the divergent evolution of A. caldus species. We identified a diverse pool of mobile genetic elements including insertion sequences and genomic islands, which suggests a high frequency of genetic exchange in these harsh habitats. Comprehensive analysis revealed that gene gains and losses were both dominant evolutionary forces that directed the genomic diversification of A. caldus species. For instance, horizontal gene transfer and gene duplication events in group 2 strains might contribute to an increase in microbial DNA content and novel functions. Moreover, genomes undergo extensive changes in group 1 strains such as removal of potential non-functional DNA, which results in the formation of compact and streamlined genomes. Taken together, the findings presented herein show highly frequent gene turnover of A. caldus species that inhabit extremely acidic environments, and shed new light on the contribution of gene turnover to the evolutionary adaptation of acidophiles.

Applied microbiology and biotechnology, 2017

Acetoclastic methanogenesis is a key metabolic process in anaerobic digestion, a technology with ... more Acetoclastic methanogenesis is a key metabolic process in anaerobic digestion, a technology with broad applications in biogas production and waste treatment. Acetoclastic methanogenesis is known to be performed by two archaeal genera, Methanosaeta and Methanosarcina. The conventional model posits that Methanosaeta populations are more competitive at low acetate levels (<1 mM) than Methanosarcina and vice versa at higher acetate concentrations. While this model is supported by an extensive body of studies, reports of inconsistency have grown that Methanosaeta were observed to outnumber Methanosarcina at elevated acetate levels. In this study, monitoring of anaerobic digesters treating animal wastewater unexpectedly identified Methanosaeta as the dominant acetoclastic methanogen population at both low and high acetate levels during organic overloading. The surprising competitiveness of Methanosaeta at elevated acetate was further supported by the enrichment of Methanosaeta with hig...

Journal of industrial microbiology & biotechnology, Jun 28, 2016

To identify potential linkages between specific bacterial populations and process performance in ... more To identify potential linkages between specific bacterial populations and process performance in anaerobic digestion, the dynamics of bacterial community structure was monitored with high-throughput sequencing in triplicate anaerobic digesters treating animal waste. Firmicutes and Bacteroidetes were found as the two most abundant populations, however, with contrasting population dynamics in response to organic overloading. Firmicutes dominated the bacterial community during stable process performance at low organic loading rate, representing over 50 % of the bacterial abundance. In contrast, the onset of organic overloading raised the relative abundance of Bacteroidetes from 20 ± 2.6 to 44 ± 3.1 %. In addition to the significant negative correlation between the relative abundance of Firmicutes and Bacteroidetes, populations of Firmicutes and Bacteroidetes were found to be linked to process parameters including organic loading rate, volatile fatty acids concentration, and methane pro...

Ecotoxicology (London, England), Jan 25, 2015

Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in proc... more Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free ch...

Biodegradation, 2002

Anaeromyxobacter dehalogenans strain 2CP-C dehalogenates ortho-substituted di- and mono-halogenat... more Anaeromyxobacter dehalogenans strain 2CP-C dehalogenates ortho-substituted di- and mono-halogenated phenols and couples this activity to growth. Reductive dehalogenation activity has been reported to be inducible, however, this process has not been studied extensively. In this study, the induction of reductive dehalogenation activity by strain 2CP-C is characterized. Constitutive 2-chlorophenol dechlorination activity occurs in non-induced fumarate-grown cells, with rates averaging 0.138 micromol of Cl- h(-1) mg of protein(-1). Once induced, these cultures dechlorinate 2- chlorophenol (2-CP) at rates as high as 116 micromol of Cl(-1) h(-1) mg of protein(-1). Dechlorination of 2-CP is induced by phenol, 2-chlorophenol, 2,4-dichlorophenol, 2,5-dichlorophenol, 2,6-dichlorophenol, and 2-bromophenol. Of the substrates tested, 2-bromophenol shows the highest induction potential, yielding double the 2-chlorophenol dechlorination rate when compared to other inducing substrates. No induced d...

The ISME Journal, 2010

Sulfate-reducing bacteria (SRB) have been extensively studied for their potential in heavy metal ... more Sulfate-reducing bacteria (SRB) have been extensively studied for their potential in heavy metal bioremediation. However, the occurrence of elevated nitrate in contaminated environments has been shown to inhibit sulfate reduction activity. While the inhibition has been suggested to result from competition with nitrate-reducing bacteria, the possibility of direct inhibition of sulfate reducers by elevated nitrate needs to be explored. Using Desulfovibrio vulgaris as a model sulfate-reducing bacterium, functional genomics analysis reveals that osmotic stress contributed to growth inhibition by nitrate as demonstrated by the up-regulation of the glycine/betaine transporter genes and the relief of nitrate inhibition by osmoprotectant. The observation that significant growth inhibition was affected by 70 mM NaNO 3 but not 70 mM NaCl suggests the presence of inhibitory mechanisms in addition to osmotic stress. The differential expression of genes characteristic of nitrite stress responses, such as the hybrid cluster protein gene, under nitrate stress condition further indicates that nitrate stress response by D. vulgaris was linked to components of both osmotic and nitrite stress responses. The involvement of the oxidative stress response pathway, however, might be the result of a more general stress response. Given the low similarities between the response profiles to nitrate and other stresses, less defined stress response pathways could also be important in nitrate stress, which might involve the shift in energy metabolism. The involvement of nitrite stress response upon exposure to nitrate may provide detoxification mechanisms for nitrite, which is inhibitory to SRB, produced by microbial nitrate reduction as a metabolic intermediate and enhance the survival of sulfate-reducing bacterial in environments with elevated nitrate level.

Renewable Energy, 2011

Grease trap waste (GTW) presents a challenge to wastewater treatment processes due to its slow bi... more Grease trap waste (GTW) presents a challenge to wastewater treatment processes due to its slow biodegradation kinetics, high oxygen demand, and risks of pipeline blockage. The objective of this work was to evaluate the feasibility of GTW as an organic-rich co-substrate to improve biomethane production in the anaerobic digestion of municipal waste sludge (MWS) from sewage treatment, one of the most abundant feed materials to municipal anaerobic digesters. Waste characterization confirmed the high organic content of GTW at 138 gVS/L, which was 626% higher than that of MWS (19 gVS/L). The methane potential of GTW approximated 145 L Methane /L GTW , which was more than 15 times higher than that of MWS (8.9 L Methane / L MWS). When GTW was added as a co-substrate in addition to MWS, the high methane potential and organic content of GTW resulted in significant improvement in methane production during the anaerobic codigestion of MWS, e.g. a 65% increase at the GTW loading of 5.5 gVS/L, representing a less than 4% (vol/vol) addition of GTW. Thus, the operational feasibility of anaerobic co-digestion using GTW as the co-substrate is enhanced by the insignificant volumetric GTW loading required for significant improvements in methane production. Process inhibition and reduction in biogas production, however, occurred with higher GTW loadings, suggesting the importance of proper GTW loading rates for the implementation of anaerobic codigestion processes effective in improving biomethanation of municipal waste sludge.

Materials, 2014

Over the vast Northwest China, arid desert contains high concentrations of sulfate, chloride, and... more Over the vast Northwest China, arid desert contains high concentrations of sulfate, chloride, and other chemicals in the ground water, which poses serious challenges to infrastructure construction that routinely utilizes portland cement concrete. Rapid industrialization in the region has been generating huge amounts of mineral admixtures, such as fly ash and slags from energy and metallurgical industries. These industrial by-products would turn into waste materials if not utilized in time. The present study evaluated the suitability of utilizing local mineral admixtures in significant quantities for producing quality concrete mixtures that can withstand the harsh chemical environment without compromising the essential mechanical properties. Comprehensive chemical, mechanical, and durability tests were conducted in the laboratory to characterize the properties of the local cementitious mineral admixtures, cement mortar and portland cement concrete mixtures containing these admixtures. The results from this study indicated that the sulfate resistance of concrete was effectively improved by adding local class F fly ash and slag, or by applying sulfate resistance cement to the mixtures. It is noteworthy that concrete containing local mineral admixtures exhibited much lower permeability (in terms of chloride ion penetration) than ordinary portland cement concrete

Journal of the American Water Resources Association, 2002

Vegetated submerged bed wetlands can supplement treatment of onsite wastewater systems. This stud... more Vegetated submerged bed wetlands can supplement treatment of onsite wastewater systems. This study evaluated vegetation, media, and seasonal impacts on system performance in six meso scale rock plant filters with and without narrow leaf cattails (Typha augustifolia). Daily chemical oxygen demand (COD) reductions in planted cells averaged 85 percent and weekly total nitrogen (TN) reductions averaged 50 percent. Planted cells had 17 percent greater COD reduction and 76 percent greater TN reduction than unplanted cells, both significant differences. Media type affected COD reduction, particularly in unplanted cells. COD treatment in planted cells was highest for fine crushed limestone (87±13 percent) and least variable for coarse river gravel (85±11 percent). No significant difference in TN reduction was observed for different media types (48 to 51 percent range). Seasonal influences on treatment included a significant decrease during late fall and early spring and a significant increase with temperature. After a step increase in organic loading, treatment efficiency decreased sharply but returned to prior levels after an adaptation period of about one month. Planted cells not only exhibited higher treatment efficiency but also had a retarded organic matter breakthrough, appearing after three to seven times the period for a bromide tracer. This supports a hypothesis that retardation of contaminant movement through the treatment cells results in enhanced removal. These results support the use of rock plant filters, but demonstrate the need to account for performance variations in system design.

Journal of Bacteriology, 2006

The ability of Desulfovibrio vulgaris Hildenborough to reduce, and therefore contain, toxic and r... more The ability of Desulfovibrio vulgaris Hildenborough to reduce, and therefore contain, toxic and radioactive metal waste has made all factors that affect the physiology of this organism of great interest. Increased salinity is an important and frequent fluctuation faced by D. vulgaris in its natural habitat. In liquid culture, exposure to excess salt resulted in striking elongation of D. vulgaris cells. Using data from transcriptomics, proteomics, metabolite assays, phospholipid fatty acid profiling, and electron microscopy, we used a systems approach to explore the effects of excess NaCl on D. vulgaris. In this study we demonstrated that import of osmoprotectants, such as glycine betaine and ectoine, is the primary mechanism used by D. vulgaris to counter hyperionic stress. Several efflux systems were also highly up-regulated, as was the ATP synthesis pathway. Increases in the levels of both RNA and DNA helicases suggested that salt stress affected the stability of nucleic acid base...

Journal of Bacteriology, 2006

Desulfovibrio vulgaris Hildenborough belongs to a class of sulfate-reducing bacteria (SRB) and is... more Desulfovibrio vulgaris Hildenborough belongs to a class of sulfate-reducing bacteria (SRB) and is found ubiquitously in nature. Given the importance of SRB-mediated reduction for bioremediation of metal ion contaminants, ongoing research on D. vulgaris has been in the direction of elucidating regulatory mechanisms for this organism under a variety of stress conditions. This work presents a global view of this organism's response to elevated growth temperature using whole-cell transcriptomics and proteomics tools. Transcriptional response (1.7-fold change or greater; Z ≥ 1.5) ranged from 1,135 genes at 15 min to 1,463 genes at 120 min for a temperature up-shift of 13°C from a growth temperature of 37°C for this organism and suggested both direct and indirect modes of heat sensing. Clusters of orthologous group categories that were significantly affected included posttranslational modifications; protein turnover and chaperones (up-regulated); energy production and conversion (down...

Journal of Bacteriology, 2007

The response of exponentially growing Desulfovibrio vulgaris Hildenborough to pH 10 stress was st... more The response of exponentially growing Desulfovibrio vulgaris Hildenborough to pH 10 stress was studied using oligonucleotide microarrays and a study set of mutants with genes suggested by microarray data to be involved in the alkaline stress response deleted. The data showed that the response of D. vulgaris to increased pH is generally similar to that of Escherichia coli but is apparently controlled by unique regulatory circuits since the alternative sigma factors (sigma S and sigma E) contributing to this stress response in E. coli appear to be absent in D. vulgaris. Genes previously reported to be up-regulated in E. coli were up-regulated in D. vulgaris; these genes included three ATPase genes and a tryptophan synthase gene. Transcription of chaperone and protease genes (encoding ATP-dependent Clp and La proteases and DnaK) was also elevated in D. vulgaris. As in E. coli, genes involved in flagellum synthesis were down-regulated. The transcriptional data also identified regulators...

Environmental Microbiology, 2000

To understand how sulphate-reducing bacteria respond to oxidative stresses, the responses of Desu... more To understand how sulphate-reducing bacteria respond to oxidative stresses, the responses of Desulfovibrio vulgaris Hildenborough to H 2 O 2-induced stresses were investigated with transcriptomic, proteomic and genetic approaches. H 2 O 2 and induced chemical species (e.g. polysulfide, ROS) and redox potential shift increased the expressions of the genes involved in detoxification, thioredoxin-dependent reduction system, protein and DNA repair, and decreased those involved in sulfate reduction, lactate oxidation and protein synthesis. A gene coexpression network analysis revealed complicated network interactions among differentially expressed genes, and suggested possible importance of several hypothetical genes in H 2 O 2 stress. Also, most of the genes in PerR and Fur regulons were highly induced, and the abundance of a Fur regulon protein increased. Mutant analysis suggested that PerR and Fur are functionally overlapped in response to stresses induced by H 2 O 2 and reaction products, and the upregulation of thioredoxin-dependent reduction genes was independent of PerR or Fur. It appears that induction of those stress response genes could contribute to the increased resistance of deletion mutants to H 2 O 2-induced stresses. In addition, a conceptual cellular model of D. vulgaris responses to H 2 O 2 stress was constructed to illustrate that this bacterium may employ a complicated molecular mechanism to defend against the H 2 O 2-induced stresses.

Bulletin of Environmental Contamination and Toxicology, 2009

Soil pollution by cadmium has been a long standing ecological problem in Zhangshi Irrigation Area... more Soil pollution by cadmium has been a long standing ecological problem in Zhangshi Irrigation Area, Shenyang, China, as a result of the 30-year practice of irrigation with wastewater containing high levels of heavy metals. To evaluate the adverse impact of cadmium contamination on soil ecosystems, the responses of soil microbiota to both long-term and short-term cadmium stress were studied by molecular microbial community profiling with denaturating gradient gel electrophoresis (DGGE) analysis. Our results show that soil characteristics and nutrient conditions were likely more important than cadmium toxicity in shaping the soil bacterial community structure in the long term. In comparison, soil microbial genetic diversity was shown to be more closely correlated to cadmium levels under short-term cadmium stress, with the highest microbial genetic diversity occurring at mild cadmium stress conditions, which might be attributed to the enrichment of metal-resistant microbial populations through mechanisms of competitive selection and genetic adaptation. In contrast, severe cadmium stress likely presented a condition that fewer microbial populations could survive, thus leading to reduced microbial genetic diversity.

BMC Genomics, 2007

Background: Groundwater and subsurface environments contaminated with aromatic compounds can be r... more Background: Groundwater and subsurface environments contaminated with aromatic compounds can be remediated in situ by Geobacter species that couple oxidation of these compounds to reduction of Fe(III)-oxides. Geobacter metallireducens metabolizes many aromatic compounds, but the enzymes involved are not well known. Results: The complete G. metallireducens genome contained a 300 kb island predicted to encode enzymes for the degradation of phenol, p-cresol, 4-hydroxybenzaldehyde, 4-hydroxybenzoate, benzyl alcohol, benzaldehyde, and benzoate. Toluene degradation genes were encoded in a separate region. None of these genes was found in closely related species that cannot degrade aromatic compounds. Abundant transposons and phage-like genes in the island suggest mobility, but nucleotide composition and lack of synteny with other species do not suggest a recent transfer. The inferred degradation pathways are similar to those in species that anaerobically oxidize aromatic compounds with nitrate as an electron acceptor. In these pathways the aromatic compounds are converted to benzoyl-CoA and then to 3-hydroxypimelyl-CoA. However, in G. metallireducens there were no genes for the energetically-expensive dearomatizing enzyme. Whole-genome changes in transcript levels were identified in cells oxidizing benzoate. These supported the predicted pathway, identified induced fatty-acid oxidation genes, and identified an apparent shift in the TCA cycle to a putative ATP-yielding succinyl-CoA synthase. Paralogs to several genes in the pathway were also induced, as were several putative molybdo-proteins. Comparison of the aromatics degradation pathway genes to the genome of an isolate from a contaminated field site showed very similar content, and suggested this strain degrades many of the same compounds. This strain also lacked a classical dearomatizing enzyme, but contained two copies of an eight-gene cluster encoding redox proteins that was 30-fold induced during benzoate oxidation. Conclusion: G. metallireducens appears to convert aromatic compounds to benzoyl-CoA, then to acetyl-CoA via fatty acid oxidation, and then to carbon dioxide via the TCA cycle. The enzyme responsible for dearomatizing the aromatic ring may be novel, and energetic investments at this step may be offset by a change in succinate metabolism. Analysis of a field isolate suggests that the pathways inferred for G. metallireducens may be applicable to modeling in situ bioremediation.

Archives of Microbiology, 2008

Sulfate-reducing bacteria (SRB) are anaerobes readily found in oxic-anoxic interfaces. Multiple d... more Sulfate-reducing bacteria (SRB) are anaerobes readily found in oxic-anoxic interfaces. Multiple defense pathways against oxidative conditions were identiWed in these organisms and proposed to be diVerentially expressed under diVerent concentrations of oxygen, contributing to their ability to survive oxic conditions. In this study, Desulfovibrio vulgaris Hildenborough cells were exposed to the highest concentration of oxygen that SRB are likely to encounter in natural habitats, and the global transcriptomic response was determined. Three hundred and seven genes were responsive, with cellular roles in energy metabolism, protein fate, cell envelope and regulatory functions, including multiple genes encoding heat shock proteins, peptidases and proteins with heat shock promoters. Of the oxygen reducing mechanisms of D. vulgaris only the periplasmic hydrogen-dependent mechanism was up-regulated, involving the [NiFeSe] hydrogenase, formate dehydrogenase(s) and the Hmc membrane complex. The oxidative defense response concentrated on damage repair by metalfree enzymes. These data, together with the down-regulation of the ferric uptake regulator operon, which restricts the availability of iron, and the lack of response of the peroxide-sensing regulator operon, suggest that a major eVect of this oxygen stress is the inactivation and/or degradation of multiple metalloproteins present in D. vulgaris as a consequence of oxidative damage to their metal clusters. Keywords Oxidative stress • Desulfovibrio • Genomics • Metalloproteins • Fur • PerR • Thioredoxin • Hmc Abbreviations D Desulfovibrio PMF Proton motive force ROS Reactive oxygen species SRB Sulfate-reducing bacteria Communicated by Friedrich Widdel. António V. Xavier-deceased May 2006.

Applied and Environmental Microbiology, 2007

Previous experiments examining the transcriptional profile of the anaerobe Desulfovibrio vulgaris... more Previous experiments examining the transcriptional profile of the anaerobe Desulfovibrio vulgaris demonstrated up-regulation of the Fur regulon in response to various environmental stressors. To test the involvement of Fur in the growth response and transcriptional regulation of D. vulgaris, a targeted mutagenesis procedure was used for deleting the fur gene. Growth of the resulting Δfur mutant (JW707) was not affected by iron availability, but the mutant did exhibit increased sensitivity to nitrite and osmotic stresses compared to the wild type. Transcriptional profiling of JW707 indicated that iron-bound Fur acts as a traditional repressor for ferrous iron uptake genes (feoAB) and other genes containing a predicted Fur binding site within their promoter. Despite the apparent lack of siderophore biosynthesis genes within the D. vulgaris genome, a large 12-gene operon encoding orthologs to TonB and TolQR also appeared to be repressed by iron-bound Fur. While other genes predicted to...

Ultrasonics sonochemistry, 2018

The ISME journal, Dec 25, 2017

Frontiers in Microbiology, 2016

Applied microbiology and biotechnology, 2017

Journal of industrial microbiology & biotechnology, Jun 28, 2016

Ecotoxicology (London, England), Jan 25, 2015

Biodegradation, 2002

The ISME Journal, 2010

Renewable Energy, 2011

Materials, 2014

Journal of the American Water Resources Association, 2002

Journal of Bacteriology, 2006

Journal of Bacteriology, 2007

Environmental Microbiology, 2000

Bulletin of Environmental Contamination and Toxicology, 2009

BMC Genomics, 2007

Archives of Microbiology, 2008

Applied and Environmental Microbiology, 2007