Dracunculiasis in South Indian bonnet monkey

Dracunculiasis, popularly known as Guinea worm disease, has been eradicated from Tamil Nadu, India, and there have been no indigenous cases reported since 1981. This report describes a female bonnet monkey with dracunculiasis. She presented with fever and a blister in left hind limb. The blister ruptured on exposure to water and a 7-cm-long worm was extruded. The worm died before it could be histologically examined. The diagnosis was based on the typical clinical course, which was pathognomonic of dracunculiasis. Review of literature did not reveal any previous report of dracunculiasis in South Indian bonnet monkeys (Macaca radiata). This paper raises the question whether wild monkeys might act as reservoirs of human infection and cause resurgence of the disease in South India. Animal experiments were approved by the ethical committee of our institute and animal maintenance was according to the recommendations of the Canadian Council for Experimental Animal Care and the Laboratory Animal Science Association of India.     

Scaffold hybridization in generation of indenoindolones as anticancer agents that induce apoptosis with cell cycle arrest at G2/M phase

Scaffold hybridization of several natural and synthetic anticancer leads led to the consideration of indenoindolones as potential novel anticancer agents. A series of these compounds were prepared by a diversity-feasible synthetic method. They were found to possess anticancer activities with higher potency compared to etoposide and 5-fluorouracil in kidney cancer cells (HEK 293) and low toxicity to corresponding normal cells (Vero). They exerted apoptotic effect with blocking of cell cycle at G2/M phase.     

Site-directed mutagenesis to determine essential residues of ribulose-bisphosphate carboxylase ofRhodospirillum rubrum

Both Lys-166 and His-291 of ribulosebisphosphate carboxylase/oxygenase fromRhodospirillum rubrum have been implicated as the active-site residue that initiates catalysis. To decide between these two candidates, we resorted to site-directed mutagenesis to replace Lys-166 and His-291 with several amino acids. All 7 of the position-166 mutants tested are severely deficient in carboxylase activity, whereas the alanine and serine mutants at position 291 are ∼40% and ∼18% as active as the native carboxylase, essentially ruling out His-291 in theRhodospirillum rubrum carboxylase (and by inference His-298 in the spinach enzyme) as a catalytically essential residue. The ability of some of the mutant proteins to undergo carbamate formation or to bind either ribulosebisphosphate or a transition-state analogue remains largely unimpaired. This implies that Lys-166 is not required for substrate binding; rather, the results corroborate the earlier postulate that Lys-166 functions as an acid-base group in catalysis or in stabilizing a transition state in the reaction pathway.     

High proportions of deleterious polymorphisms in constrained human genes

Previous studies on human mitochondrial genomes showed that the ratio of intra-specific diversities at nonsynonymous-to-synonymous positions was two to ten times higher than the ratio of interspecific divergences at these positions, suggesting an excess of slightly deleterious nonsynonymous polymorphisms. However, such an overabundance of nonsynonymous single nucleotide polymorphisms (SNPs) was not found in human nuclear genomes. Here, genome-wide estimates using >14,000 human-chimp nuclear genes and 1 million SNPs from four human genomes showed a significant proportion of deleterious nonsynonymous SNPs (～ 15%). Importantly, this study reveals a negative correlation between the magnitude of selection pressure and the proportion of deleterious SNPs on human genes. The proportion of deleterious amino acid replacement polymorphisms is 3.5 times higher in genes under high purifying selection compared with that in less constrained genes (28% vs. 8%). These results are explained by differences in the extent of contribution of mildly deleterious mutations to diversity and substitution.     

The deubiquitinase activity of A20 is dispensable for NF‐κB signaling

A20 has been suggested to limit NF‐κB activation by removing regulatory ubiquitin chains from ubiquitinated substrates. A20 is a ubiquitin‐editing enzyme that removes K63‐linked ubiquitin chains from adaptor proteins, such as RIP1, and then conjugates them to K48‐linked polyubiquitin chains to trigger proteasomal degradation. To determine the role of the deubiquitinase function of A20 in downregulating NF‐κB signaling, we have generated a knock‐in mouse that lacks the deubiquitinase function of A20 (A20‐OTU mice). These mice are normal and have no signs of inflammation, have normal proportions of B, T, dendritic, and myeloid cells, respond normally to LPS and TNF, and undergo normal NF‐κB activation. Our results thus indicate that the deubiquitinase activity of A20 is dispensable for normal NF‐κB signaling.     

Polymorphism and nucleotide sequencing of BMPR1B gene in prolific Assam hill goat

Assam hill goat (Capra hircus) is a prolific local goat in India. bone morphogenetic protein receptor (BMPR1B) gene was studied as a candidate gene for the prolificacy of goats. The objective of the present study was to detect the incidence of mutation in the exonic region of BMPR1B gene of Assam hill goat. Total 90 blood samples were collected randomly from different parts of Assam and genomic DNA were extracted using phenol–chloroform method. The quantity and quality of extracted DNA was examined by spectrophotometry and gel electrophoresis, respectively. PCR amplicon showed a product of 140 bp fragment of BMPR1B gene. The purified product upon digestion with AvaII showed monomorphic banding pattern and revealed wild type alleles with AA genotype. Nucleotide sequencing showed one new mutation 773 (G→C) which is found to be unique in Assam hill goat. Construction of tree at nucleotide level generates from the present experiment lies in common cluster which differs from the other breeds of goat. The analysis of polymorphism for BMPR1B in Assam hill goat indicates that the genetic factor responsible for prolificacy or multiple kidding rates is not related to the reported mutated alleles of BMPR1B gene. Therefore, attempts to be made to detect other SNPs for BMPR1B gene or otherwise effort should be made towards other fecundity gene which might be responsible for the prolificacy of Assam hill goat.     

Sphingolipid storage induces accumulation of intracellular cholesterol by stimulating SREBP-1 cleavage

We showed previously that the intracellular transport of sphingolipids (SLs) is altered in SL storage disease fibroblasts, due in part to the secondary accumulation of free cholesterol. In the present study we examined the mechanism of cholesterol elevation in normal human skin fibroblasts induced by treatment with SLs. When cells were incubated with various natural SLs for 44 h, cholesterol levels increased 25-35%, and cholesterol esterification was reduced. Catabolism of the exogenous SLs was not required for elevation of cholesterol because (i) a non-hydrolyzable and a degradable SL analog elevated cellular cholesterol to similar extents, and (ii) incubation of cells with various SL catabolites, including ceramide, had no effect on cholesterol levels. Elevated cholesterol was derived primarily from low density lipoproteins (LDL) and resulted from up-regulation of LDL receptors induced by cleavage of the sterol regulatory element-binding protein-1. Upon SL treatment, cholesterol accumulated with exogenous SLs in late endosomes and lysosomes. These results suggest a model in which excess SLs present in endocytic compartments serve as a "molecular trap" for cholesterol, leading to a reduction in cholesterol at the endoplasmic reticulum, induction of sterol regulatory element-binding protein-1 cleavage, and up-regulation of LDL receptors.