Project description:Manufactured nanomaterials (MNMs) are increasingly incorporated into consumer products that are disposed into sewage. In wastewater treatment, MNMs adsorb to activated sludge biomass where they may impact biological wastewater treatment performance, including nutrient removal. Here, we studied MNM effects on bacterial polyhydroxyalkanoate (PHA), specifically polyhydroxybutyrate (PHB), biosynthesis because of its importance to enhanced biological phosphorus (P) removal (EBPR). Activated sludge was sampled from an anoxic selector of a municipal wastewater treatment plant (WWTP), and PHB-containing bacteria were concentrated by density gradient centrifugation. After starvation to decrease intracellular PHB stores, bacteria were nutritionally augmented to promote PHB biosynthesis while being exposed to either MNMs (TiO2 or Ag) or to Ag salts (each at a concentration of 5 mg L-1). Cellular PHB concentration and PhyloChip community composition were analyzed. The final bacterial community composition differed from activated sludge, demonstrating that laboratory enrichment was selective. Still, PHB was synthesized to near-activated sludge levels. Ag salts altered final bacterial communities, although MNMs did not. PHB biosynthesis was diminished with Ag (salt or MNMs), indicating the potential for Ag-MNMs to physiologically impact EBPR through the effects of dissolved Ag ions on PHB producers. 18 samples; Triplicate PHB-enriched bacterial communities recovered from activated sludge were exposed to nanoparticle (TiO2 or Ag) or AgNO3 (as a silver control) or were not exposed to an nanoparticles (control) to determine if the naoparticles affected PHB production.
Project description:Manufactured nanomaterials (MNMs) are increasingly incorporated into consumer products that are disposed into sewage. In wastewater treatment, MNMs adsorb to activated sludge biomass where they may impact biological wastewater treatment performance, including nutrient removal. Here, we studied MNM effects on bacterial polyhydroxyalkanoate (PHA), specifically polyhydroxybutyrate (PHB), biosynthesis because of its importance to enhanced biological phosphorus (P) removal (EBPR). Activated sludge was sampled from an anoxic selector of a municipal wastewater treatment plant (WWTP), and PHB-containing bacteria were concentrated by density gradient centrifugation. After starvation to decrease intracellular PHB stores, bacteria were nutritionally augmented to promote PHB biosynthesis while being exposed to either MNMs (TiO2 or Ag) or to Ag salts (each at a concentration of 5 mg L-1). Cellular PHB concentration and PhyloChip community composition were analyzed. The final bacterial community composition differed from activated sludge, demonstrating that laboratory enrichment was selective. Still, PHB was synthesized to near-activated sludge levels. Ag salts altered final bacterial communities, although MNMs did not. PHB biosynthesis was diminished with Ag (salt or MNMs), indicating the potential for Ag-MNMs to physiologically impact EBPR through the effects of dissolved Ag ions on PHB producers.
Project description:The biodegradable polymer poly-β-hydroxybutyrate (PHB) is a promising carbon source for biological mitigation of nitrogen pollution, a significant problem in aquaculture that physical and chemical methods have not provided a comprehensive solution. Here we investigated the impact of PHB on the zero-water-change largemouth bass culture by 30- and 40-day experiments. PHB loaded into the filter circulation pump at 4g L-1, optimum value determined by the first experiment, significantly reduced the levels of nitrate by 99.65%, nitrite by 95.96%, and total nitrogen by 85.22% compared to the control without PHB. PHB also significantly increased denitrifying bacteria (e.g., Proteobacteria and Fusobacteria) and expression of denitrification genes (e.g., nirK and nirS) in the microbial community, improving growth and health parameters of largemouth bass. While the impact may vary in other culture systems, PHB thus demonstrated its remarkable utility in aquaculture, highlighting ecological assessment and application to larger aquaculture operations as future considerations.
Project description:Dietary lipids can affect metabolic health through gut microbiota-mediated mechanisms, but the influence of lipid-microbiota interaction on liver steatosis is unknown. We investigated the effect of dietary lipid composition on human microbiota in an observational study and combined diet experiments with microbiota transplants to study lipid-microbiota interactions and liver status in mice. In humans, low intake of saturated fatty acids (SFA) was associated with increased microbial diversity independent of fiber intake. In mice, cecum levels of SFA correlated negatively with microbial diversity and were associated with a shift in butyrate and propionate producers. Mice fed poorly absorbed SFA had improved metabolism and liver status. These features were transmitted by microbial transfer. Diets enriched in n-6- and/or n-3-polyunsaturated fatty acids were protective against steatosis but had minor influence on the microbiota. In summary, we find that unabsorbed SFA correlate with microbiota features that may be targeted to decrease liver steatosis.
Project description:Cellular metabolism and chromatin landscape both contribute to cell fate determination. However, their interplay remains poorly understood. Here we show that Prohibitin (PHB), an evolutionarily conserved protein, involves in a histone variant H3.3 chaperon HIRA complex-dependent epigenetic and metabolic circuitry to maintain the identity of human embryonic stem cells (hESCs). We found that silencing of PHB triggers hESC differentiation with concomitant enhancements of histone 3 (H3) lysine (K) methyl modifications as a result of the reduced production of α-ketoglutarate (α-KG), a metabolite required for activities of many dioxygenase and in turn chromatin structure1,2. Mechanistically, PHB acts as a functional member of the HIRA complex3,4. Resembling PHB deficiency, loss of HIRA in hESCs leads to massive differentiation and aberrant histone modifications, although it was previously found not to disrupt the self-renewal in mouse ESCs (mESCs)5. Genome-wide H3.3 ChIP- sequence analyses indicate that reduction of H3.3 deposition caused by PHB knock down is extremely similar to that induced by HIRA knock down. Specifically, silencing either HIRA or PHB leads to repressive chromatin characters at promoters of pluripotency genes and isocitrate dehydrogenases (IDHs), the enzyme responsible for α-KG production, but active chromatin features at promoters of developmental genes, paralleling to transcript levels of these genes. Our results identify PHB as an essential factor not only for hESC self-renewal but also for the proper function of the HIRA complex, linking the HIRA complex-dependent H3.3 deposition to the production of a critical metabolite required for shaping chromatin structure, and demonstrating the importance of the interplay between epigenetic state and metabolic regulation in cell fate determination. Examination of H3.3 deposition in NT, PHB, and HIRA siRNA treated hESCs respectively.
Project description:Prohibitin (PHB) plays a significant role in cancer processes whereas its mechanism in bladder cancer (BC) aggressiveness is not fully understood. This study aimed to investigate the role of PHB in BC aggressiveness. The study employed a range of in vivo and in vitro assays to elucidate the interaction between PHB-NADSYN1 and its underlying function in BC progression. We found that PHB was upregulated in muscle-invasive bladder cancer tissues, and bound to NADSYN1 mRNA in BC tissues more than in adjacent normal tissues. NADSYN1 and PHB were upregulated and positively correlated both in BC tissues and cell lines. We further revealed that deleting NADSYN1 prevented PHB-mediated cell invasiveness of BC in vivo and in vitro. PHB could directly bind to NADSYN1 mRNA, and it was found that the PHB domain was responsible for the PHB-NADSYN1 interaction. Depletion of NADSYN1 expression significantly decreased the protein level of PHB. In addition, Snai2 positively correlated with NADSYN1 and depletion or mutation of Snai2 binding sites inhibited NADSYN1-PHB-mediated BC progression. The study highlights a novel Snai2-NADSYN1-PHB mechanism in BC progression and indicates that PHB and NADSYN1 could serve as a therapeutic target for BC
Project description:To effectively monitor microbial populations in acidic environments and bioleaching systems, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the known genes associated with the acidophiles. This array contained 1,072 probes in which there were 571 related to 16S rRNA and 501 related to functional genes. Acid mine drainage (AMD) presents numerous problems to the aquatic life and surrounding ecosystems. However, little is known about the geographic distribution, diversity, composition, structure and function of AMD microbial communities. In this study, we analyzed the geographic distribution of AMD microbial communities from twenty sites using restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes, and the results showed that AMD microbial communities were geographically distributed and had high variations among different sites. Then an AMD-specific microarray was used to further analyze nine AMD microbial communities, and showed that those nine AMD microbial communities had high variations measured by the number of detected genes, overlapping genes between samples, unique genes, and diversity indices. Statistical analyses indicated that the concentrations of Fe, S, Ca, Mg, Zn, Cu and pH had strong impacts on both phylogenetic and functional diversity, composition, and structure of AMD microbial communities. This study provides insights into our understanding of the geographic distribution, diversity, composition, structure and functional potential of AMD microbial communities and key environmental factors shaping them. This study investigated the geographic distribution of Acid Mine Drainages microbial communities using a 16S rRNA gene-based RFLP method and the diversity, composition and structure of AMD microbial communities phylogenetically and functionally using an AMD-specific microarray which contained 1,072 probes ( 571 related to 16S rRNA and 501 related to functional genes). The functional genes in the microarray were involved in carbon metabolism (158), nitrogen metabolism (72), sulfur metabolism (39), iron metabolism (68), DNA replication and repair (97), metal-resistance (27), membrane-relate gene (16), transposon (13) and IST sequence (11).
Project description:Cellular metabolism and chromatin landscape both contribute to cell fate determination. However, their interplay remains poorly understood. Here we show that Prohibitin (PHB), an evolutionarily conserved protein, involves in a histone variant H3.3 chaperon HIRA complex-dependent epigenetic and metabolic circuitry to maintain the identity of human embryonic stem cells (hESCs). We found that silencing of PHB triggers hESC differentiation with concomitant enhancements of histone 3 (H3) lysine (K) methyl modifications as a result of the reduced production of α-ketoglutarate (α-KG), a metabolite required for activities of many dioxygenase and in turn chromatin structure1,2. Mechanistically, PHB acts as a functional member of the HIRA complex3,4. Resembling PHB deficiency, loss of HIRA in hESCs leads to massive differentiation and aberrant histone modifications, although it was previously found not to disrupt the self-renewal in mouse ESCs (mESCs)5. Genome-wide H3.3 ChIP- sequence analyses indicate that reduction of H3.3 deposition caused by PHB knock down is extremely similar to that induced by HIRA knock down. Specifically, silencing either HIRA or PHB leads to repressive chromatin characters at promoters of pluripotency genes and isocitrate dehydrogenases (IDHs), the enzyme responsible for α-KG production, but active chromatin features at promoters of developmental genes, paralleling to transcript levels of these genes. Our results identify PHB as an essential factor not only for hESC self-renewal but also for the proper function of the HIRA complex, linking the HIRA complex-dependent H3.3 deposition to the production of a critical metabolite required for shaping chromatin structure, and demonstrating the importance of the interplay between epigenetic state and metabolic regulation in cell fate determination.