Intestinal microsomes: polyunsaturated fatty acid metabolism and regulation of enterocyte transport properties

Recent evidence has suggested that transport of nutrients from the lumen to the interior of the gastrointestinal epithelium and exit of nutrients from the enterocyte to the circulation is governed by physicochemical properties of brush border and basolateral membranes, respectively. The main determinants of membrane properties are phospholipid, cholesterol, and fatty acyl chain composition (chain length and degree of unsaturation). Lipid synthesis occurs in enterocyte microsomes and the fine tuning of lipid composition is done at other subcellular sites by deacylation-reacylation or by changing the polar head group (e.g., by phosphatidylethanolamine methyltransferase). The present paper will focus on the mechanisms by which enterocyte membranes adapt functional properties in response to external stimuli. It is proposed that under the influence of internal or external stress, the enzymes of lipid metabolism in microsomes are modulated. These changes in lipid synthesis are reflected in other subcellular membranes, changing their physicochemical status and thus transport phenomena. One of the initial events appears to be alteration in desaturase enzyme activity. Our results suggest that desaturase activity and the fatty acyl profiles of the intestinal mucosal phospholipid rapidly respond to physiological conditions such as fasting and dietary fat treatment.     

Effect of cultural factors on cellulase activity and protein production by Aspergillus terreus

Protein production by Aspergillus terreus GN1 grown on 1.0% alkali-treated bagasse was studied under various cultural conditions. The maximum biomass protein content of 20.1% and protein recovery of 11.2% was obtained with an initial pH of 4.0, with 1/5 (v/v) inoculum in continuously shaken cultures grown for seven days. Protein content of the alkali-treated bagasse was 3.0%. Highest crude protein percent also corresponded with highest carboxymethyl cellulase and filter paper enzyme activities.     

Exploration of highly selective fluorogenic ‘on–off' chemosensor for H2PO4− ions: ICT‐based sensing and ATPase activity profiling

Abstract In this study, the recognition contour of Chemosensor 1 was investigated using semiaqueous methanol (X_H, mole fraction = 0.31) for a range of anions and bioactive species. Host–receptor signalling based on the internal charge transfer mechanism for Chemosensor 1 was explored and reported. Structure of Chemosensor 1 and its plausible anion coordination based on hydrogen bonding is complemented with density functional theory. Consequently, we investigated the applicability of the synthesized probe in blood plasma, urine, tap water samples, and for monitoring of ATP in lysosomes by apyrase enzyme.     

Metals toxicity and its correlation with the gene expression in Alzheimer's disease

Molecular Biology Reports - Alzheimer's disease is a common neurodegenerative disease in the elderly population and a leading cause of dementia. Genetics and environmental risk factors were...     

Peroxisome Proliferator-Activated Receptor-Gamma (PPAR-ɣ): Molecular Effects and Its Importance as a Novel Therapeutic Target for Cerebral Ischemic Injury

Neurochemical Research - Cerebral ischemic injury is a leading cause of death and long-term disability throughout the world. Peroxisome proliferator-activated receptor gamma (PPAR-?) is a...     

DNA Polymerases that Propagate the Eukaryotic DNA Replication Fork

Abstract

Three DNA polymerases are thought to function at the eukaryotic DNA replication fork. Currently, a coherent model has been derived for the composition and activities of the lagging strand machinery. RNA-DNA primers are initiated by DNA polymerase α -primase. Loading of the proliferating cell nuclear antigen, PCNA, dissociates DNA polymerase α and recruits DNA polymerase δ and the flap endonuclease FEN1 for elongation and in preparation for its requirement during maturation, respectively. Nick translation by the strand displacement action of DNA polymerase δ, coupled with the nuclease action of FEN1, results in processive RNA degradation until a proper DNA nick is reached for closure by DNA ligase I. In the event of excessive strand displacement synthesis, other factors, such as the Dna2 nuclease/helicase, are required to trim excess flaps. Paradoxically, the composition and activity of the much simpler leading strand machinery has not been clearly established. The burden of evidence suggests that DNA polymerase ε normally replicates this strand, but under conditions of dysfunction, DNA polymerase δ may substitute.     

A new subspecies of Pedicularis zeylanica (Scrophulariaceae) from the Western Ghats of south India

Pedicularis zeylanica subsp. anamallyensis T. Husain & A. Garg, a new subspecies of Nilgiri lousewort from the Western Ghats of south India, is described and illustrated.     

Synthesis of a Smart Gold Nano‐vehicle for Liver Specific Drug Delivery

Targeting drug formulations to specific tissues and releasing the bioactive content in response to a certain stimuli remains a significant challenge in the field of biomedical science. We have developed a nanovehicle that can be used to deliver “drugs” to “specific” tissues. For this, we have simultaneously modified the surface of the nanovehicle with “drugs” and “tissue-specific ligands”. The “tissue-specific ligands” will target the nanovehicle to the correct tissue and release the “drug” of interest in response to specific stimuli. We have synthesised a “lactose surface-modified gold nanovehicle” to target liver cells and release the model fluorescent drug (coumarin derivative) in response to the differential glutathione concentration (between blood plasma and liver cells). Lactose is used as the liver-specific targeting ligand given the abundance of l-galactose receptors in hepatic cells. The coumarin derivative is used as a fluorescent tag as well as a linker for the attachment of various biologically relevant molecules. The model delivery system is compatible with a host of different ligands and hence could be used to target other tissues as well in future. The synthesised nanovehicle was found to be non-toxic to cultured human cell lines even at elevated non-physiological concentrations as high as 100 μg/mL. We discover that the synthesised gold-based nanovehicle shows considerable stability at low extracellular glutathione concentrations; however coumarin is selectively released at high hepatic glutathione concentration.