N/S element transformation modulating lithospheric microbial communities by single-species manipulation.

BACKGROUND: The lithospheric microbiome plays a vital role in global biogeochemical cycling, yet their mutual modulation mechanisms remain largely uncharted. Petroleum reservoirs are important lithosphere ecosystems that provide desirable resources for understanding microbial roles in element cycling. However, the strategy and mechanism of modulating indigenous microbial communities for the optimization of community structures and functions are underexplored, despite its significance in energy recovery and environmental remediation. RESULTS: Here we proposed a novel selective stimulation of indigenous functional microbes by driving nitrogen and sulfur cycling in petroleum reservoirs using injections of an exogenous heterocycle-degrading strain of Pseudomonas. We defined such bacteria capable of removing and releasing organically bound sulfur and nitrogen from heterocycles as "bioredox triggers". High-throughput 16S rRNA amplicon sequencing, metagenomic, and gene transcription-level analyses of extensive production water and sandstone core samples spanning the whole oil production process clarified the microbiome dynamics following the intervention. These efforts demonstrated the feasibility of in situ N/S element release and electron acceptor generation during heterocycle degradation, shifting microbiome structures and functions and increasing phylogenetic diversity and genera engaged in sulfur and nitrogen cycling, such as Desulfovibrio, Shewanella, and Sulfurospirillum. The metabolic potentials of sulfur- and nitrogen-cycling processes, particularly dissimilatory sulfate reduction and dissimilatory nitrate reduction, were elevated in reservoir microbiomes. The relative expression of genes involved in sulfate reduction (dsrA, dsrB) and nitrate reduction (napA) was upregulated by 85, 28, and 22 folds, respectively. Field trials showed significant improvements in oil properties, with a decline in asphaltenes and aromatics, hetero-element contents, and viscosity, hence facilitating the effective exploitation of heavy oil. CONCLUSIONS: The interactions between microbiomes and element cycling elucidated in this study will contribute to a better understanding of microbial metabolic involvement in, and response to, biogeochemical processes in the lithosphere. The presented findings demonstrated the immense potential of our microbial modulation strategy for green and enhanced heavy oil recovery. Video Abstract.

CO2 improves the anaerobic biodegradation intensity and selectivity of heterocyclic hydrocarbons in heavy oil.

Heterocyclic hydrocarbons pollution generated by oil spills and oilfield wastewater discharges threatens the ecological environment and human health. Here we described a strategy that combines the greenhouse gas CO2 reduction with microbial remediation. In the presence of nitrate, CO2 can improve the biodegradation efficiency of the resins and asphaltenes in heavy oil, particularly the biodegradation selectivity of the polar heterocyclic compounds by the newly isolated Klebsiella michiganensis. This strain encoded 80 genes for the xenobiotic biodegradation and metabolism, and can efficiently utilize CO2 when degrading heavy oil. The total abundance of resins and asphaltenes decreased significantly with CO2, from 40.816% to 26.909%, to 28.873% with O2, and to 36.985% with N2. The transcripts per million (TPM) value of accA gene was 57.81 under CO2 condition, while respectively 8.86 and 21.23 under O2 and N2 conditions. Under CO2 condition, the total relative percentage of N1-type heterocyclic compounds was selectively decreased from 32.25% to 22.78%, resulting in the heavy oil viscosity decreased by 46.29%. These results demonstrated a novel anaerobic degradation mechanism that CO2 can promote the anaerobic biodegradation of heterocyclic hydrocarbons in heavy oil, which provides a promising biotreatment technology for the oil-contaminated water.

Deep mining decreases the microbial taxonomic and functional diversity of subsurface oil reservoirs.

Microbes in subsurface oil reservoirs play important roles in elemental cycles and biogeochemical processes. However, the community assembly pattern of indigenous microbiome and their succession under long-term human activity remain poorly understood. Here we studied the microbial community assembly in underground sandstone cores from 190 to 2050 m in northeast China and their response to long-term oil recovery (10-50 years). Indigenous microbiome in subsurface petroleum reservoirs were dominated by Gammaproteobacteria, Firmicutes, Alphaproteobacteria, Bacteroidetes, and Actinobacteria, which exhibited a higher contribution of homogenizing dispersal assembly and different taxonomy distinct ecological modules when compared with perturbed samples. Specifically, the long-term oil recovery reduced the bacterial taxonomic- and functional-diversity, and increased the community co-occurrence associations in subsurface oil reservoirs. Moreover, distinguished from the perturbed samples, both variation partition analysis and structural equation model revealed that the contents of quartz, NO3- and Cl- significantly structured the α- and ß-diversity in indigenous subsurface bacterial communities. These findings first provide the holistic picture of microbiome in the deep oil reservoirs, which demonstrate the significant impact of human activity on microbiome in deep continental subsurface.

Bacterial and Archaeal Community Distribution in Oilfield Water Re-injection Facilities and the Influences from Microorganisms in Injected Water.

Water flooding is widely employed for oil production worldwide. However, there has never been a systematic investigation of the microbial communities occurring in oilfield water re-injection facilities. Here, we investigated the distribution of bacterial and archaeal communities in water re-injection facilities of an oilfield, and illustrated the combined influences of environmental variation and the microorganisms in injected water on the microbial communities. Bacterial communities from the surface injection facilities were dominated by aerobic or facultative anaerobic Betaproteobacteria, Alphaproteobacteria, and Flavobacteria, whereas Clostridia, Deltaproteobacteria, Anaerolineae, and Synergistia predominated in downhole of the injection wells, and Gammaproteobacteria, Betaproteobacteria, and Epsilonproteobacteria predominated in the production wells. Methanosaeta, Methanobacterium, and Methanolinea were dominant archaea in the injection facilities, while Methanosaeta, Methanomethylovorans, and Methanoculleus predominated in the production wells. This study also demonstrated that the microorganisms in injected water could be easily transferred from injection station to wellheads and downhole of injection wells, and environmental variation and diffusion-limited microbial transfer resulted from formation filtration were the main factors determining microbial community assembly in oil-bearing strata. The results provide novel information on the bacterial and archaeal communities and the underlying mechanisms occurring in oilfield water re-injection facilities, and benefit the development of effective microbiologically enhanced oil recovery and microbiologically prevented reservoir souring programs.

Altered Gut Microbiota is Involved in the Anti-Hypertensive Effects of Vitamin C in Spontaneously Hypertensive Rat.

SCOPE: Gut dysbiosis and dysregulation of the gut-brain-axis contributes to the pathogenesis of hypertension. Vitamin C (VC) is a common dietary supplement that shows the ability to lower the elevated blood pressure in hypertensive animals. Thus, the hypothesis that the gut microbiota is involved in the anti-hypertensive effect of VC is proposed. METHODS AND RESULTS: The changes of the gut microbiota and pathology in a spontaneously hypertensive rat (SHR) model after daily oral intake of VC in dosage of 200 or 1000 mg kg-1 are examined. After 4 weeks, the elevated blood pressure of SHRs in both VC-treated groups is attenuated. Sequencing of the gut microbiota shows improvement in its diversity and abundance. Bioinformatic analysis suggests restored metabolism and biosynthesis-related functions of the gut, which are confirmed by the improvement of gut pathology and integrity. Analysis of the hypothalamus paraventricular nucleus (PVN), the central pivot of blood pressure regulation, also shows reduced inflammatory responses and oxidative stress. CONCLUSIONS: The reduced blood pressure, enriched gut microbiota, improved gut pathology and integrity, and reduced inflammatory responses and oxidative stress in the PVN together suggest that the anti-hypertensive effects of VC involve reshaping of gut microbiota composition and function.

Exercise and food supplement of vitamin C ameliorate hypertension through improvement of gut microflora in the spontaneously hypertensive rats.

AIMS: Exercise and food supplement of vitamin C (VC) are beneficial to human health, especially for those who suffer from hypertension. Here we tend to explore if gut microflora is involved in the anti-hypertensive effects of exercise and VC-supplement therapies. MATERIALS AND METHODS: With the spontaneously hypertensive rat (SHR) model, the small intestine pathology and the fecal microbiota was analyzed along with the pro- and anti-inflammatory cytokines (PICs and AICs) and reactive oxygen species (ROS) in the hypothalamus paraventricular nucleus (PVN) and intestine. KEY FINDINGS: We found that both exercise and VC intake, individually or combined, were able to alleviate the blood pressure in the SHRs comparing to the normotensive control Wistar-kyoto (WKY) rats. The expression level of PICs in the PVN and intestine of the SHRs was down-regulated while the AICs were up-regulated after treatments, together with down-regulation of ROS in the PVN. At meantime, the gut pathology was dramatically improved in the SHRs with exercise training or VC intake. Analysis of the gut microflora revealed significant changes in their composition. Several important micro-organisms that were deficient in the SHRs were found up-regulated by the treatments, including Turicibacter and Romboutsia which are involved in the short-chain fatty acid production. SIGNIFICANCE: Exercise training and VC intake individually can modify the gut microflora composition and improve the inflammatory state in both PVN and intestine, which contribute to their anti-hypertensive function. Combination of the two treatments enhanced their effects and worth to be considered as a non-medical aid for the hypertensive patients.

Oridonin Suppresses Human Gastric Cancer Growth in Vitro and in Vivo via Inhibition of VEGF, Integrin ß3, and PCNA.

The diterpenoid oridonin is an extract from the herb Rabdosia rubescens, commonly used in Traditional Chinese medicine. Oridonin has putative inhibitory activity in many human cancers. This study continued investigations into the therapeutic potential of oridonin against gastric carcinoma, and the underlying mechanism. An in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with BGC823 cells was used to examine the cytotoxicity and apoptosis associated with oridonin treatment. RT-PCR and immunocytochemistry results showed evaluated levels of vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), integrin ß3, and proliferating cell nuclear antigen (PCNA) in BGC823 cells, or BGC823 xenografts nude mice. The inhibitory effect of oridonin was determined in vivo using the xenograft model, comparing tumor weight and volume, and calculating the tumor inhibition rate. The oridonin treatment and control groups were compared for associations between microvessel density and tumor inhibition rate, VEGF mRNA, integrin ß3 mRNA, and PCNA protein. The IC50s of oridonin at 12 and 72 h were 17.08 ± 2.38 and 8.76 ± 0.90 µg/mL, respectively. VEGF protein levels dramatically decreased in a time- and dose-dependent manner with oridonin treatment. BGC823 xenograft growth was notably less in the oridonin treatment groups, responding in a dose-dependent manner. After 14 d of treatment, VEGF, integrin ß3, and PCNA levels were dramatically lower, and positively correlated with CD31 levels. Oridonin was associated with inhibition of BGC823 cell growth and tumor angiogenesis, in vitro and in vivo, in a dose-and-time dependent manner with lower levels of VEGF, integrin ß3, and PCNA. Oridonin is a potential candidate agent for chemotherapy of gastric carcinoma.

Integrative analysis of copy number and transcriptional expression profiles in esophageal cancer to identify a novel driver gene for therapy.

An increasing amount of evidence has highlighted the critical roles that copy number variants play in cancer progression. Here, we systematically analyzed the copy number alterations and differentially transcribed genes. Integrative analysis of the association between copy number variants and differential gene expression suggested that copy number variants will lead to aberrant expression of the corresponding genes. We performed a KEGG pathway and GO analysis, which revealed that cell cycle may have an effective role in the progression of esophageal cancer. FAM60A was then screened out as a potential prognostic factor through survival analysis and correlation analysis with clinical-pathological parameters. We subsequently showed that silencing of FAM60A could inhibit esophageal carcinoma tumor cell growth, migration and invasion in vitro. Through the bioinformatic analysis, we predict that FAM60A may act as a transcriptional factor to regulate genes that are correlated with each cell cycle. In summary, we comprehensively analyzed copy number segments and transcriptional expression profiles, which provided a novel approach to identify clinical biomarkers and therapeutic targets of esophageal carcinoma.

Synthesis, characterization, and oil recovery application of biosurfactant produced by indigenous pseudomonas aeruginosa WJ-1 using waste vegetable oils.

A bacterial strain was isolated and cultured from the oil excavation areas in tropical zone in northern China. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, WJ-1, was identical to those of cultured representatives of the species Pseudomonas aeruginosa. This bacterium was able to produce a type of biosurfactant. Compositional analysis revealed that the extracted biosurfactant was composed of high percentage lipid (∼74%, w/w) and carbohydrate (∼20%, w/w) in addition to a minor fraction of protein (∼6%, w/w). The best production of 50.2 g/l was obtained when the cells were grown on minimal salt medium containing 6.0% (w/v) glucose and 0.75% (w/v) sodium nitrate supplemented with 0.1% (v/v) element solution at 37 °C and 180 rpm after 96 h. The optimum biosurfactant production pH value was found to be 6.0-8.0. The biosurfactant of WJ-1, with the critical micelle concentration of 0.014 g/L, could reduce surface tension to 24.5 mN/m and emulsified kerosene up to EI(24) ≈95. The results obtained from time course study indicated that the surface tension reduction and emulsification potential was increased in the same way to cell growth. However, maximum biosurfactant production occurred and established in the stationary growth phase (after 90 h). Thin layer chromatography, Fourier transform infrared spectrum, and mass spectrum analysis indicate the extracted biosurfactant was affiliated with rhamnolipid. The core holder flooding experiments demonstrated that the oil recovery efficiency of strain and its biosurfactant was 23.02% residual oil.