Role of thymine in protein coding frames of mRNA sequences

Distribution of thymine in protein coding mRNA sequences has been studied here. Our study suggest that thymine in protein coding sequences are not randomly distributed but with probability. Frame1 prefers to have definite amount of thymine. It is observed that the thymine content of frame 4 is also involved in protein coding. Frame 3 prefers to have least amount of thymine. However, frame 2 and frame 6 shows a variable degree of thymine content. The mRNA sequences of heterosexual animals, particularly, the human show a different distribution profile (less thymine in frame 1) compared to that of yeast and plants.     

Photophysics of ruthenium(II) complexes carrying amino acids in the ligand 2,2′-bipyridine and intramolecular electron transfer from methionine to photogenerated Ru(III)

New ruthenium(II) complexes carrying methionine and phenylalanine in the bipyridine ligand, [Ru(bpy)₂(4-Me-4′-(CONH-l-methionine methyl ester)-2,2′-bipyridine)](PF₆)₂ (IV) and [Ru(bpy)₂(4-Me-4′-(CONH-l-phenylalanine ethyl ester)-2,2′-bpy)](PF₆)₂(V) have been synthesized and characterized and their photophysical properties studied. Flash photolysis measurements of complex IV, in the presence of an electron acceptor, methyl viologen (MV²⁺) show that an intermolecular electron transfer from the excited state of Ru(II) in complex IV, to MV²⁺ takes place, forming Ru(III) and the methyl viologen cation radical, MV⁺. The formation of MV⁺ in this system is confirmed using time-resolved transient absorption spectroscopy. This intermolecular electron transfer is followed by intramolecular electron transfer from the thioether moiety (methionine) to the photogenerated Ru(III), regenerating Ru(II).     

Wet chemical synthesis of chitosan hydrogel–hydroxyapatite composite membranes for tissue engineering applications

Chitosan, a deacetylated derivative of chitin is a commonly studied biomaterial for tissue-engineering applications due to its biocompatibility, biodegradability, low toxicity, antibacterial activity, wound healing ability and haemostatic properties. However, chitosan has poor mechanical strength due to which its applications in orthopedics are limited. Hydroxyapatite (HAp) is a natural inorganic component of bone and teeth and has mechanical strength and osteoconductive property. In this work, HAp was deposited on the surface of chitosan hydrogel membranes by a wet chemical synthesis method by alternatively soaking the membranes in CaCl₂ (pH 7.4) and Na₂HPO₄ solutions for different time intervals. These chitosan hydrogel–HAp membranes were characterized using SEM, AFM, EDS, FT-IR and XRD analyses. MTT assay was done to evaluate the biocompatibility of these membranes using MG-63 osteosarcoma cells. The biocompatibility studies suggest that chitosan hydrogel–HAp composite membranes can be useful for tissue-engineering applications.     

Solubilized phenyl-pyrazole ureas as potent, selective 5-HT2A inverse-agonists and their application as antiplatelet agents

Potent 5-HT_2A inverse-agonists containing phenyl-pyrazole ureas with an amino side chain were identified. Optimization of this series resulted in selective compounds that proved effective in modulating 5HT-induced amplification of ADP-stimulated human platelet aggregation.     

Regioselective synthesis and biological evaluation of bis(indolyl)methane derivatized 1,4-disubstituted 1,2,3-bistriazoles as anti-infective agents

The regioselective synthesis of 1,4-disubstituted 1,2,3-bistriazoles from a variety of N-propargyl bis(indolyl)methanes with sodium azide using CuI as the catalyst in polyethyleneglycol-400 is reported. This process is of considerable synthetic advantages in terms of high atom economy, low environmental impact, mild reaction condition and good yields. The synthesized compounds have also been screened for their biological activity.     

A microwave-assisted facile regioselective Fischer indole synthesis and antitubercular evaluation of novel 2-aryl-3,4-dihydro-2H-thieno[3,2-b]indoles

A series of novel 2-aryl-3,4-dihydro-2H-thieno[3,2-b]indoles has been synthesised regioselectively in good yields from the reaction of 5-aryldihydro-3(2H)-thiophenones and arylhydrazine hydrochloride. This reaction is found to be assisted by microwaves. The thieno[3,2-b]indoles were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug resistant M. tuberculosis (MDR-TB). Among 22 compounds screened, [2-(2,4-dichlorophenyl)-7-fluoro-3,4-dihydro-2H-thieno[3,2-b]indole] (6t) was found to the most active compound with MIC of 0.4 μg/mL against MTB and MDR-TB.     

Denitrifying Bacterial Community Composition Changes Associated with Stages of Denitrification in Oxygen Minimum Zones

Denitrification in the ocean is a major sink for fixed nitrogen in the global N budget, but the process is geographically restricted to a few oceanic regions, including three oceanic oxygen minimum zones (OMZ) and hemipelagic sediments worldwide. Here, we describe the diversity and community composition of microbes responsible for denitrification in the OMZ using polymerase chain reaction, sequence and fragment analysis of clone libraries of the signature genes (nirK and nirS) that encode the enzyme nitrite reductase, responsible for key denitrification transformation steps. We show that denitrifying assemblages vary in space and time and exhibit striking changes in diversity associated with the progression of denitrification from initial anoxia through nitrate depletion. The initial denitrifying assemblage is highly diverse, but succession on the scale of 3–12 days leads to a much less diverse assemblage and dominance by one or a few phylotypes. This progression occurs in the natural environment as well as in enclosed incubations. The emergence of dominants from a vast reservoir of rare types has implications for the maintenance of diversity of the microbial population and suggests that a small number of microbial dominants may be responsible for the greatest rates of transformations involving nitrous oxide and global fixed nitrogen loss. Denitrifying blooms, driven by a few types responding to episodic environmental changes and distributed unevenly in time and space, are consistent with the sampling effect model of diversity–function relationships. Canonical denitrification thus appears to have important parallels with both primary production and nitrogen fixation, which are typically dominated by regionally and temporally restricted blooms that account for a disproportionate share of these processes worldwide.     

Synthesis and antimalarial activity of new 4-amino-7-chloroquinolyl amides,sulfonamides, ureas and thioureas

We report the synthesis and in vitro antimalarial activities of more than 50 7-chloro-4-aminoquinolyl-derived sulfonamides 3–8 and 11–26, ureas 19–22, thioureas 23–26, and amides 27–54. Many of the CQ analogues prepared for this study showed submicromolar antimalarial activity versus HB3 (chloroquine sensitive) and Dd2 (chloroquine resistant strains of Plasmodium falciparum) and low resistance indices were obtained in most cases. Systematic variation of the side chain length and introduction of fluorinated aliphatic and aromatic termini revealed promising leads that overcome CQ resistance. In particular, sulfonamide 3 exhibiting a short side chain with a terminal dansyl moiety combined high antiplasmodial potency with a low resistance index and showed IC₅₀s of 17.5 and 22.7 nM against HB3 and Dd2 parasites.     

Could adrenal insufficiency serve as a predictor of immune reconstitution inflammatory syndrome (IRIS) in HIV disease?

Immune reconstitution inflammatory syndrome (IRIS) is an inflammatory manifestation that occurs subsequent to initiation of highly active antiretroviral therapy in terminal (HAART) HIV infection, mainly due to the restoration of robust immune responses directed against latent microbial antigens. IRIS is believed to be multifactorial and less studied. Herein, we postulate that hypothalamo-pituitary-adrenal (HPA) dysregulation, a well-documented manifestation in HIV/AIDS, could possibly disturb the balance between pro-inflammatory and anti-inflammatory cytokines leading to clinical IRIS. Drugs, opportunistic infections, stress and numerous intrinsic and extrinsic factors have been described to be the possible causes of IRIS in HIV illness.