Adipogenic cell line TA1: a suitable model to study the effect of beta-adrenergic agonists on lipid metabolism.

The stable adipogenic cell line TA1 was investigated as a potential in vitro system to examine effects of beta-adrenergic agonists on lipid metabolism at the cellular level. Initial experiments were conducted to establish whether dexamethasone, indomethacin, or both in combination induce rapid differentiation of TA1 preadipocytes to adipocytes. Based on activity of fatty acid synthase, dexamethasone and indomethacin, individually and in combination, were observed to induce differentiation in TA1 cells at different rates (dexamethasone/indomethacin greater than indomethacin greater than dexamethasone). Dexamethasone/indomethacin induced complete differentiation in TA1 cells 4 days after confluence, as indicated by increased activity of fatty acid synthase, glycerol-3-phosphate dehydrogenase, and malic enzyme. Finally, mature TA1 adipocytes were treated with various concentrations of isoproterenol and ractopamine to determine the responsiveness of TA1 adipocytes to a beta-adrenergic challenge. Glycerol release was increased and fatty acid synthase activity was decreased in a dose-dependent manner for both isoproterenol and ractopamine. These results indicate that fully differentiated TA1 adipocytes may be useful to study direct cellular effects of lipolytic and lipogenic agents on lipid metabolism.     

Regional Amino Acid Distribution in Relation to Function in Insulin Hypoglycaemia

The amino acids glutamate, aspartate, gamma-aminobutyric acid (GABA), and glutamine were measured as their dansyl derivatives in whole brain and specific brain regions by a sensitive double-labelling technique at various times during the development of hypoglycaemic encephalopathy. Hypoglycaemia was induced by administration of insulin (100 i.u./kg) to 24-h fasted rats. No significant changes in glutamate, GABA, or glutamine were detected in whole brain at any time up to and including the onset of hypoglycaemic convulsions. In cerebral cortex, however, GABA levels were reduced to 65% or normal prior to the appearance of neurological symptoms of hypoglycaemia. Onset of symptoms (severe catalepsy and loss of righting reflex, but before the onset of convulsions) was accompanied by marked decreases of glutamate and glutamine in striatum and hippocampus. These regions, in addition to cerebral cortex, show the greatest vulnerability to hypoglycaemic insult, according to previous anatomical studies. Aspartate levels were significantly increased (p less than 0.01) in the cerebral cortex of convulsing animals, confirming a previous report. No changes were detectable in any of the amino acids studied in medulla-pons at any time during the progression of hypoglycaemia. Cerebral cortex and striatum showed a selective net loss of amino acids (2.2 and 3.5 mumol/g. respectively) prior to the onset of insulin-hypoglycaemic convulsions.     

Effects of Plectin Depletion on Keratin Network Dynamics and Organization

The keratin intermediate filament cytoskeleton protects epithelial cells against various types of stress and is involved in fundamental cellular processes such as signaling, differentiation and organelle trafficking. These functions rely on the cell type-specific arrangement and plasticity of the keratin system. It has been suggested that these properties are regulated by a complex cycle of assembly and disassembly. The exact mechanisms responsible for the underlying molecular processes, however, have not been clarified. Accumulating evidence implicates the cytolinker plectin in various aspects of the keratin cycle, i.e., by acting as a stabilizing anchor at hemidesmosomal adhesion sites and the nucleus, by affecting keratin bundling and branching and by linkage of keratins to actin filament and microtubule dynamics. In the present study we tested these hypotheses. To this end, plectin was downregulated by shRNA in vulvar carcinoma-derived A431 cells. As expected, integrin β4- and BPAG-1-positive hemidesmosomal structures were strongly reduced and cytosolic actin stress fibers were increased. In addition, integrins α3 and β1 were reduced. The experiments furthermore showed that loss of plectin led to a reduction in keratin filament branch length but did not alter overall mechanical properties as assessed by indentation analyses using atomic force microscopy and by displacement analyses of cytoplasmic superparamagnetic beads using magnetic tweezers. An increase in keratin movement was observed in plectin-depleted cells as was the case in control cells lacking hemidesmosome-like structures. Yet, keratin turnover was not significantly affected. We conclude that plectin alone is not needed for keratin assembly and disassembly and that other mechanisms exist to guarantee proper keratin cycling under steady state conditions in cultured single cells.     

Modulation of glycogen metabolism in cerebromicrovascular smooth muscle and endothelial cultures

The separately cultured smooth muscle and endothelial cells derived from dissociated cerebral microvessels are characterized by high content of glycogen. Norepinephrine induces glycogenolysis while 5-hydroxytryptamine stimulates glycogenesis in both cell types. The endogenous glucose of the endothelium but not that of the smooth muscle serves as a direct source for the 5-HT enhancement of glycogen formation. Indomethacin, the known inhibitor of cyclooxygenase modulates the glycogen content in the smooth muscle only. These findings strongly suggest that the carbohydrate metabolism of each cell has a distinct control mechanism compatible with the underlying integral microvascular function.     

Pseudodesulfovibrio alkaliphilus,sp. nov., an alkaliphilic sulfate-reducing bacterium isolated from a terrestrial mud volcano

Antonie van Leeuwenhoek - The diversity of anaerobic microorganisms in terrestrial mud volcanoes is largely unexplored. Here we report the isolation of a novel sulfate-reducing alkaliphilic...     

Erratum to: On the Possibility of Aerobic Methane Production by Pelagic Microbial Communities of the Laptev Sea

Microbiology - An Erratum to this paper has been published: https://doi.org/10.1134/S0026261721110011     

On the Possibility of Aerobic Methane Production by Pelagic Microbial Communities of the Laptev Sea

Microbiology - The taxonomic diversity and metabolic activity of microbial communities in the Laptev Sea water column above and outside the methane seep field were studied. The concentrations of...     

Identification of Aerobic Methane-Oxidizing Bacteria in Coastal Sediments of the Crimean Peninsula

Microbiology - Methane oxidation rates and diversity of methane-oxidizing microorganisms in the upper sediment layers of the Crimean Peninsula coastal regions (Black Sea) were investigated....     

Identification of Small Molecule Inhibitors of Jumonji AT-rich Interactive Domain 1B (JARID1B) Histone Demethylase by a Sensitive High Throughput Screen

JARID1B (also known as KDM5B or PLU1) is a member of the JARID1 family of histone lysine demethylases responsible for the demethylation of trimethylated lysine 27 in histone H3 (H3K4me3), a mark for actively transcribed genes. JARID1B is overexpressed in several cancers, including breast cancer, prostate cancer, and lung cancer. In addition, JARID1B is required for mammary tumor formation in syngeneic or xenograft mouse models. JARID1B-expressing melanoma cells are associated with increased self-renewal character. Therefore, JARID1B represents an attractive target for cancer therapy. Here we characterized JARID1B using a homogeneous luminescence-based demethylase assay. We then conducted a high throughput screen of over 15,000 small molecules to identify inhibitors of JARID1B. From this screen, we identified several known JmjC histone demethylase inhibitors, including 2,4-pyridinedicarboxylic acid and catechols. More importantly, we identified several novel inhibitors, including 2-4(4-methylphenyl)-1,2-benzisothiazol-3(2H)-one (PBIT), which inhibits JARID1B with an IC₅₀ of about 3 μm in vitro. Consistent with this, PBIT treatment inhibited removal of H3K4me3 by JARID1B in cells. Furthermore, this compound inhibited proliferation of cells expressing higher levels of JARID1B. These results suggest that this novel small molecule inhibitor is a lead compound that can be further optimized for cancer therapy.     

Impacts of cage culture on physico-chemical and bacteriological water quality in Lake Volta,Ghana

The effects of cage fish farming on physico-chemical and bacteriological water quality in Lake Volta, Ghana, were investigated in 2013–2014. Farmed and unfarmed (control) areas of the lake were selected for monitoring. Nutrients, temperature, dissolved oxygen, conductivity, turbidity, pH, total coliforms, Pseudomonas and Vibrio spp. in the water were monitored monthly. Analyses of the water samples were carried out according to standard procedures. Physico-chemical quality of the water in both farm and control sites were within ranges typical of minimally impacted water and did not vary significantly between the two contrasting sites. The bacteriological analysis, however, revealed contamination of the lake water by fish farming. The bacterial counts at the farmed sites were significantly higher (p < 0.05) than those of the control sites, with figures at the farmed sites ranging from 132 to 1 708 cfu 100 ml?1 for total coliforms, 514 to 5 170 cfu 100 ml?1 Pseudomonas spp. and 14 to 516 cfu 100 ml?1 for Vibrio spp. The results suggested that cage fish farming has increased bacterial loads in the lake water, but has had minimal impact on its physico-chemical quality.