Project description:We report the isolation of the first bacterial strain, Sphingobium sp. AntQ-1, with the ability to grow on the oxy-PAH anthraquinone as sole carbon and energy source. We combine genomic, transcriptomic and metabolomic analysis to comprehensively elucidate the anthraquinone metabolic pathway and to identify key degradative genes.
Project description:Members of the bacterial phylum Spirochaetes are primarily studied for their commensal and pathogenic roles in animal hosts. However, Spirochaetes are also frequently detected in anoxic hydrocarbon-contaminated environments but their ecological role in such ecosystems has so far remained unclear. Here we provide a functional trait to these frequently detected organisms with an example of a sulfate-reducing, naphthalene-degrading enrichment culture consisting of a sulfate-reducing deltaproteobacterium Desulfobacterium naphthalenivorans and a novel spirochete Rectinema cohabitans. Using a combination of genomic, proteomic, and physiological studies we show that R. cohabitans grows by fermentation of organic compounds derived from biomass from dead cells (necromass). It recycles the derived electrons in the form of H2 to the sulfate-reducing D. naphthalenivorans, thereby supporting naphthalene degradation and forming a simple microbial loop. We provide metagenomic evidence that equivalent associations between Spirochaetes and hydrocarbon-degrading microorganisms are of general importance in hydrocarbon- and organohalide-contaminated ecosystems. We propose that environmental Spirochaetes form a critical component of a microbial loop central to nutrient cycling in subsurface environments. This emphasizes the importance of necromass and H2-cycling in highly toxic contaminated subsurface habitats such as hydrocarbon-polluted aquifers.
Project description:This study examines the transcriptomic response of biofilms of the PAH-degrading Sphingomonas sp. LH128 on solute stress when actively degrading and growing on the PAH compound. To address the effect of solute stress on bacterial physiology and transcriptomic response, NaCl was used as osmolyte. Both acute and chronic solute stress was invoked to assess differences in short-term and long-term responses.
Project description:This study examines the transcriptomic response of biofilms of the PAH-degrading Sphingomonas sp. LH128 on solute stress when actively degrading and growing on the PAH compound. To address the effect of solute stress on bacterial physiology and transcriptomic response, NaCl was used as osmolyte. Both acute and chronic solute stress was invoked to assess differences in short-term and long-term responses. Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 biofilms as a response to short-term and long-term solute (NaCl) stress was studied using genome-wide gene expression analysis. For this purpose, the strain was grown in customized continuous glass flow chambers that contain solid phenanthrene as a sole carbon source and that allow easy recovery of biofilm cells for transcriptomic and physiological analysis. A NaCl stress of 450 mM was imposed on LH128 biofilms growing on phenanthrene crystals coated on glass slides either for 4 hours (acute stress) or for 3 days (chronic stress). RNA was extracted from the biofilm and cDNA was synthesized and labeled with Cy3. Transcriptomic response in the stressed biofilms of three replicates per conditions were analyzed and compared with non-stressed
Project description:The survival, pollutant degradation activity and transcriptome response was monitored in Sphingomonas sp. LH128 inoculated into soil. Cultivable cell numbers were determined by plating, while phenanthrene degradation was monitored by HPLC. The genetic base for the adaptive strategy of LH128 in soil was investigated by using microarray consisting 7,200 gene-coding ORFs. During 4 hours of incubation, 510 genes were differentially expressed (317 increased and 193 reduced expression) while 610 genes were differentially expressed (318 increased and 292 reduced) after 10 days of incubation. Genes with increased expression comprised of gene encoding PAH catabolic enzymes, stress resistance, oxidative stress tolerance, outer membrane proteins/porins and efflux pump proteins while the downregulated genes comprised of genes encoding flagellar biosynthesis, ribosomal proteins and ATPase. Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 inoculated into phenanthrene contaminated soil after 4h and after 10 days of incubation was studied using genome-wide gene expression analysis. For this purpose, the strain was pregrown in minimal medium and inoculated at appropriated celld densitites. RNA was extracted both from soil and and from initial inoculum and cDNA was synthesized and labeled with Cy3. Transcriptomic response in soil of three replicates per conditions after both incubation duration were analyzed and compared with the initial inoculum
Project description:Pregnancy-associated hypertensive (PAH) mice were maintained by mating females carrying the human angiotensinogen (hAGT) gene with males expressing the human renin (hRN) gene, as previously described (Takimoto E., et al., Science, 1996). Angiotensin II (AngII) has critical roles in regulation of blood pressure. In late pregnancy of PAH mice, increased AngII causes acute and severe hypertension with proteinuria. Furthermore, PAH mice show cardiac hypertrophy, fibrosis and apoptosis. It is known that AngII downregulates mRNA of alpha 1a-adrenergic receptor (Adra1a) in neonatal rat cardiac myocytes (Li H.T., et al., Circ. Res., 1997). Interestingly, we found that Adra1a knock out PAH (PAH/aKO) mice display more severe phenotype of cardiac hypertrophy in comparison to PAH mice. In this study, to understand the molecular basis of cardiac hypertrophy via regulation of Adra1a expression with AngII in PAH mice, we performed a comprehensive analysis of gene expression changes in cardiac remodeling of PAH and PAH/aKO mice using the next-generation RNA sequencing (RNA-seq).
Project description:PAH was induced by 60mg/kg MCT and an aorto-caval shunt. At different timepoints of PAH progression (day 14, 21 and 28 after MCT-injection), the left lung with PAH was hemodynamically unloading by unilateral orthotopic transplatation into a syngeneic, healthy recipient. All day 14 and 7/10 day 21 transplanted lungs showed reversal of PAH after LTx. All day 28 and 3/10 day 21 transplanted lungs showed PAH progression after LTx. Lung tissue of Reversible and Irreversible PAH and normal controls, acquired at LTx, was compared using RNA-seq.