The mesoionic compound MI-D changes energy metabolism and induces apoptosis in T98G glioma cells

Molecular and Cellular Biochemistry - The mesoionic compound 4-phenyl-5-(4-nitro-cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride (MI-D) impairs mitochondrial oxidative phosphorylation and has...     

Haloarchaeal assimilatory nitrate-reducing communities from a saline alkaline soil

Assimilatory nitrate reduction (ANR) is a pathway wherein NO₃⁻ is reduced to NH₄⁺, an N species that can be incorporated into the biomass. There is little information about the ANR genes in Archaea and most of the known information has been obtained from cultivable species. In this study, the diversity of the haloarchaeal assimilatory nitrate-reducing community was studied in an extreme saline alkaline soil of the former lake Texcoco (Mexico). Genes coding for the assimilatory nitrate reductase ( narB ) and the assimilatory nitrite reductase ( nirA ) were used as functional markers. Primers to amplify and detect partial narB and nirA were designed. The analysis of these amplicons by cloning and sequencing showed that the deduced protein fragments shared >45% identity with other NarB and NirA proteins from Euryarchaeota and <38% identity with other nitrate reductases from Bacteria and Crenarchaeota . Furthermore, these clone sequences were clustered within the class Halobacteria with strong support values in both constructed dendrograms, confirming that desired PCR products were obtained. The metabolic capacity to assimilate nitrate by these haloarchaea seems to be important given that at pH 10 and higher, NH₄⁺ is mostly converted to toxic and volatile NH₃, and NO₃⁻ becomes the preferable N source.     

Conjugated and free sterols from black bean (Phaseolus vulgaris L.) seed coats as cholesterol micelle disruptors and their effect on lipid metabolism and cholesterol transport in rat primary hepatocytes

Phytosterols have been widely studied for their cholesterol-lowering effect. Conjugated phytosterol forms have been found more active than free moieties. There are no reports about the sterol profile of black bean seed coats neither its effects on cholesterol metabolism. The aim of this research was to identify and quantify phytosterols from black bean seed coats and to determine their effects on cholesterol micellar solubility and on mRNA and key protein levels involved in lipid/cholesterol metabolism and cholesterol transport in primary rat hepatocytes. Free phytosterols, acylated steryl glycosides, and steryl glycosides were extracted from black bean seed coats. They were identified through HPLC–MS–TOF and quantified through HPLC equipped with UV–visible and evaporative light-scattering detectors. Free and conjugated phytosterols from the coats significantly increased the inhibitory effect of cholesterol micelle formation compared with stigmasterol, which was used as control (P < 0.05). In addition, phytosterols of black bean seed coat decreased lipogenesis by the downregulation of lipogenic proteins such as sterol regulatory element-binding protein 1 and fatty acid synthesis (FAS) in primary rat hepatocytes. Regarding β-oxidation, phytosterols upregulated the expression of carnitine palmitoyltransferase I and promoted the β-oxidation of long-chain fatty acids. Phytosterols inhibited cholesterol micellar solubility and reduced the activation of the liver X receptor, decreasing hepatic FAS and promoting hepatic β-oxidation of long-chain fatty acids.