Authigenic mineralization and detrital clay binding by freshwater biofilms: The Brahmani river,India

This study sought to understand the origin and fate of one of the bitumen mounds found on the bottom of Lake Baikal. These mounds are located at a depth of 900 m beneath oil spots detected on the surface of Lake Baikal (53° 18′24^″, 108° 23′20^″). The two mounds were sampled with a manipulator from a “MIR” deep-water manned submersible. Mature mound No. 8 was subjected to chemical and microbiological studies. Mound No. 3 was subjected only to chemical studies; we failed to perform microbiological analyses of this mound for logistic reasons. Oil spots collected from the water surface, samples of mound No. 3 and No. 8, were subjected to GC/MS analysis. The water contained aliphatic hydrocarbons with chains between C₈ and C₂₃, with the most abundant chain length being C₁₈. Mound No. 3 with the most abundant chain length being C₁₈ actively released oil droplets into the water. It contained 770 mg/g of C₁₃-C₃₂ n-alkanes, with a maximum at C₂₃ (160 mg/g). Mound No. 8 was inactive and contained 148 mg/g of aliphatic C₂₂-C₃₄ n-alkanes, with a maximum at C₂₅. Mound No. 8 also consisted of 3% inorganic matter, 48% unresolved complex mixture (UCM) and less than 1% other compounds (polyaromatic hydrocarbons, isoprenoids, carotenoids, and hopanes). The core of this sample used as inoculate, yielded Rhodococci when cultivated on oil as the only source of carbon. Cultivation of the sample on agar-containing Raymond inorganic medium with crude West Siberian oil as the only source of carbon revealed colonies of these bacteria, which all appeared identical. PCR was performed with DNA isolated from 5 colonies, using primers for 16S rRNA genes. Comparison of the sequences of the 5 PCR products over a length of 714 bp revealed that they were almost identical. Phylogenetic analysis of these homologous sequences showed that they were similar to the corresponding sequences of the genus Rhodococcus. Substrate demands, the morphology of the colonies, and SEM and TEM data confirmed that the isolates obtained could indeed be Rhodococci. All of the isolates could grow in bulk cultures with inorganic medium supplemented with crude oil. Moreover, all of the isolates degraded aliphatic hydrocarbons with lengths between C₁₁ and C₂₉. C₂₃-C₂₉ hydrocarbons were degraded completely. The isolates could grow at 4–37°C. The most unexpected finding was that of the many microorganisms capable of consuming oil, only Rhodococci exhibited this ability in the inactive bitumen mound. The possible mechanisms of how crude oil is transformed into bitumen mounds and mature bitumen are discussed.     

Coarse Architecture of the Transient Receptor Potential Vanilloid 1 (TRPV1) Ion Channel Determined by Fluorescence Resonance Energy Transfer

The transient receptor potential vanilloid 1 ion channel is responsible for the perception of high temperatures and low extracellular pH, and it is also involved in the response to some pungent compounds. Importantly, it is also associated with the perception of pain and noxious stimuli. Here, we attempt to discern the molecular organization and location of the N and C termini of the transient receptor potential vanilloid 1 ion channel by measuring FRET between genetically attached enhanced yellow and cyan fluorescent protein to the N or C terminus of the channel protein, expressed in transfected HEK 293 cells or Xenopus laevis oocytes. The static measurements of the domain organization were mapped into an available cryo-electron microscopy density of the channel with good agreement. These measurements also provide novel insights into the organization of terminal domains and their proximity to the plasma membrane.     

Reciprocal epithelial:endothelial paracrine interactions during thyroid development govern follicular organization and C-cells differentiation

The thyroid is a highly vascularized endocrine gland, displaying a characteristic epithelial organization in closed spheres, called follicles. Here we investigate how endothelial cells are recruited into the developing thyroid and if they control glandular organization as well as thyrocytes and C-cells differentiation. We show that endothelial cells closely surround, and then invade the expanding thyroid epithelial cell mass to become closely associated with nascent polarized follicles. This close and sustained endothelial:epithelial interaction depends on epithelial production of the angiogenic factor, Vascular Endothelial Growth Factor-A (VEGF-A), as its thyroid-specific genetic inactivation reduced the endothelial cell pool of the thyroid by >90%. Vegfa KO also displayed decreased C-cells differentiation and impaired organization of the epithelial cell mass into follicles. We developed an ex vivo model of thyroid explants that faithfully mimicks bilobation of the thyroid anlagen, endothelial and C-cells invasion, folliculogenesis and differentiation. Treatment of thyroid explants at e12.5 with a VEGFR2 inhibitor ablated the endothelial pool and reproduced ex vivo folliculogenesis defects observed in conditional Vegfa KO. In the absence of any blood supply, rescue by embryonic endothelial progenitor cells restored folliculogenesis, accelerated lumen expansion and stimulated calcitonin expression by C-cells. In conclusion, our data demonstrate that, in developing mouse thyroid, epithelial production of VEGF-A is necessary for endothelial cells recruitment and expansion. In turn, endothelial cells control epithelial reorganization in follicles and C-cells differentiation.     

Cathepsin L silencing enhances arsenic trioxide mediated in vitro cytotoxicity and apoptosis in glioblastoma U87MG spheroids

Despite improved treatment options, glioblastoma multiforme (GBM) remains the most aggressive brain tumour with the shortest post-diagnostic survival. Arsenite (As₂O₃) is already being used in the treatment of acute promyelocytic leukaemia (APL), yet its effects on GBM have not been evaluated in detail. In U87MG cell monolayers, we have previously shown that arsenite cytotoxicity significantly increases upon transient inhibition of lysosomal protease Cathepsin L (CatL). As multicellular spheroids more closely represent in vivo tumours, we aimed to evaluate the impact of permanent CatL silencing on arsenite treatment in U87MG spheroids. CatL was stably silenced using shRNA expression plasmid packed lentiviruses. By using metabolic- and cell viability assays, we demonstrated that long-term CatL silencing significantly increased arsenite cytotoxicity in U87MG spheroids. Silenced CatL also increased arsenite-mediated apoptosis in spheroids via elevated p53 expression, Bax/Bcl2 ratio and caspase 3/7 activity, though with lower efficacy than in monolayers. Arsenite cytotoxicity was enhanced by lower CatL activity, since similar cytotoxicity increase was also observed using the novel CatL inhibitor AT094. The results have significant translational impact, since stable CatL silencing would enable the application of lower systemic doses of arsenite to achieve the desired cytotoxic effects on GBMs in vivo.     

Azetidines and spiro azetidines as novel P2 units in hepatitis C virus NS3 protease inhibitors

Herein, we report the synthesis and structure–activity relationship studies of new analogs of boceprevir 1 and telaprevir 2. Introduction of azetidine and spiroazetidines as a P2 substituent that replaced the pyrrolidine moiety of 1 and 2 led to the discovery of a potent hepatitis C protease inhibitor 37c (EC₅₀ = 0.8 μM).     

Discovery of 2,5-diarylnicotinamides as selective orexin-2 receptor antagonists (2-SORAs)

The orexin (or hypocretin) system has been identified as a novel target for the treatment of insomnia due to the wealth of biological and genetic data discovered over the past decade. Recently, clinical proof-of-concept was achieved for the treatment of primary insomnia using dual (OX₁R/OX₂R) orexin receptor antagonists. However, elucidation of the pharmacology associated with selective orexin-2 receptor antagonists (2-SORAs) has been hampered by the lack of orally bioavailable, highly selective small molecule probes. Herein, the discovery and optimization of a novel series of 2,5-diarylnicotinamides as potent and orally bioavailable orexin-2 receptor selective antagonists is described. A compound from this series demonstrated potent sleep promotion when dosed orally to EEG telemetrized rats.     

Synthesis and evaluation of Janus type nucleosides as potential HCV NS5B polymerase inhibitors

The synthesis of new ribo and 2′-β-C-methyl ribo Janus type nucleosides J-AA, J-AG and J-AU is reported along with their ability to block HCV and HIV replication. Their toxicity was also assessed in Huh7, human lymphocytes, CEM and Vero cells.     

TGF-b Superfamily Cytokine MIC-1/GDF15 Is a Physiological Appetite and Body Weight Regulator

The TGF-b superfamily cytokine MIC-1/GDF15 circulates in all humans and when overproduced in cancer leads to anorexia/cachexia, by direct action on brain feeding centres. In these studies we have examined the role of physiologically relevant levels of MIC-1/GDF15 in the regulation of appetite, body weight and basal metabolic rate. MIC-1/GDF15 gene knockout mice (MIC-1^−/−) weighed more and had increased adiposity, which was associated with increased spontaneous food intake. Female MIC-1^−/− mice exhibited some additional alterations in reduced basal energy expenditure and physical activity, possibly owing to the associated decrease in total lean mass. Further, infusion of human recombinant MIC-1/GDF15 sufficient to raise serum levels in MIC-1^−/− mice to within the normal human range reduced body weight and food intake. Taken together, our findings suggest that MIC-1/GDF15 is involved in the physiological regulation of appetite and energy storage.     

Are our actions aligned With our evidence? The skinny on changing the landscape of obesity

Recent debate about the role of food deserts in the United States (i.e., places that lack access to healthy foods) has prompted discussion on policies being enacted, including efforts that encourage the placement of full‐service supermarkets into food deserts. Other initiatives to address obesogenic neighborhood features include land use zoning and parks renovations. Yet, there is little evidence to demonstrate that such policies effect change. While we suspect most researchers and policymakers would agree that effective neighborhood change could be a powerful tool in combating obesity, we desperately need strong and sound evidence to guide decisions about where and how to invest.