The serine/threonine protein kinase PknI controls the growth of Mycobacterium tuberculosis upon infection

The protein kinase PknI is one of 11 functional serine/threonine protein kinases in Mycobacterium tuberculosis . Specialized transduction was performed to create a null mutant in the pknI gene. The resulting mutant was used to determine the role of PknI in M. tuberculosis growth and infectivity. The pknI mutant grows better under acidic pH and limited oxygen availability. We observed a modest increased growth of pknI mutant within macrophages during an in vitro infection and a hypervirulence phenotype in severe combined immunodeficiency mice. The internal signals used to activate PknI are most likely the host-associated signals such as low pH associated with limited oxygen availability. Thus, we have shown that PknI plays a role in sensing the host macrophage's environment and translating it to slow the growth of M. tuberculosis within the infected host.     

Effect of TDZ and 2, 4-D on peanut somatic embryogenesis and in vitro bud development

Failure of peanut somatic embryos to convert into plantlets is attributed to the abnormal development of the plumule. Thidiazuron (TDZ) was effective in the conversion of peanut somatic embryos to plantlets by triggering morphogenetic activity in the abnormal plumules of the rooted somatic embryos. The present study aimed to induce normal embryo differentiation by culturing the embryogenic masses in embryo development medium containing 2,4-D and various concentrations of TDZ. Although this was not achieved due to restricted somatic embryo development in the presence of TDZ, bud-like projections appeared in the embryogenic masses when these were cultured in media containing combinations of 2,4-D and TDZ. These projections developed into buds, which subsequently formed shoots and plantlets. The response varied with the concentration and exposure of TDZ. At lower concentrations, the buds appeared in a defined row in the equatorial region of the explant, and with extended incubation, more and more buds appeared in rows alongside the initial row. Induction of multiple buds in a defined row in this specific site (equatorial region) suggested the presence of potent cells around this region. At higher concentrations, these projections appeared in large numbers spread over the whole upper part of the embryogenic mass starting from the equatorial region. The ability of embryogenic mass to convert into organogenic mass and to produce large number of organogenic buds provides an excellent system for basic studies and for the genetic transformation of peanut.     

Protective effect of lupeol and lupeol linoleate in hypercholesterolemia associated renal damage

The association between hypercholesterolemia and kidney damage has been well known for last few decades. The oxidative stress and inflammatory responses are involved in renal injury, which is upregulated in hypercholesterolemic condition. The present study is aimed to evaluate the possible effect of lupeol and its ester derivative, lupeol linoleate in renal damage associated with hypercholesterolemic rats. Hypercholesterolemia was induced in male Wistar rats by feeding them with a high cholesterol diet (HCD) comprising normal rat chow supplemented with 4% cholesterol and 1% cholic acid for 30 days. Lupeol and lupeol linoleate were supplemented (50 mg/kg body wt/day) to HCD fed rats during the last 15 days. Increased levels of renal total cholesterol, triglycerides and phospholipids, along with altered serum biochemical parameters of tissue injury indices and elevated activities of renal marker enzymes (lactate dehydrogenase and alkaline phosphatase) were noted in HCD fed rats. Elevated lipid peroxidation levels coupled with decreased antioxidant status (enzymatic and non enzymatic antioxidants) were observed in hypercholesterolemic rats, which indicate the onset of oxidative changes in the renal tissue. Renal lysosomal acid hydrolase activities (ACP, beta-Glu, beta-Gal, NAG and Cat-D) and acute phase proteins like C-Reactive protein and fibrinogen were significantly increased in HCD fed rats, which further indicates the heightening of inflammation. In addition, histopathological findings also confirmed the renal damage in hypercholesterolemic condition. Lupeol and lupeol linoleate effectively reverted the above abnormalities and was comparable with that of the control. These observations highlight the protective effect of lupeol and its ester derivative in ameliorating the renal injury associated with hypercholesterolemia.     

Synthesis and cardiac effects of 3,4-dihydropyrimidin-2(1H)-one-5 carboxylates

A series of 4-(substituted)-3,4-dihydropyrimidinone derivatives have been synthesized by heating 1,3 dicarbonyl compounds, urea, and aromatic aldehydes in acetic acid under microwave irradiation conditions. The cardiovascular effects of 3,4-dihydropyrimidinones were studied on isolated perfused frog heart at different dose levels and compared with the activity of digoxin. The interaction of 3,4-dihydropyrimidinones with beta-blocker and calcium channel blocker was also investigated. Compound 4d emerged as the most interesting compound in this series with potential cardiotonic activity.     

T-h-2 immunity and CD3+CD45RBlow-activated T cells in mice immunized with recombinant bacillus Calmette-Guérin expressing HIV-1 principal neutralizing determinant epitope

The genetic engineering of Mycobacterium bovis-bacillus Calmette-Guérin to express foreign epitopes is an attractive strategy in the field of epitope vaccines. We constructed an 'epitope-trap vector' with Mycobacterium tuberculosis chaperonin-10 as a carrier antigen and used it to express the HIV-1 principal neutralizing determinant epitope. We also identified a new chaperonin-10 promoter that was hyperexpressive compared with the heat shock protein-65 promoter. Splenocytes from recombinant bacillus Calmette-Guérin-immunized mice showed enhanced lymphocyte proliferation and interleukin-4 (but not interferon-gamma) secretion. The recombinant bacillus Calmette-Guérin-immunized group also exhibited mild delayed-type hypersensitivity reaction and a high frequency of CD3+CD45RBlow-activated T cells, together with high titer of antiprincipal neutralizing determinant immunoglobulin G antibodies. Thus, this epitope delivery system induced strong epitope-specific T-h-2 polarization.     

Cytotoxic compounds from the marine actinobacterium Streptomyces corchorusii AUBN1/71

We isolated a bioactive streptomycete from marine sediment samples collected at Bay of Bengal, India, during our systematic study of marine actinobacteria. The taxonomic studies indicated that the isolate is related to Strepomyces corchorusii. However, it differed in certain aspects, and, hence, was designated as S. corchorusii AUBN₁/7. A solvent extraction followed by a chromatographic purification helped obtain from the isolate two cytotoxic compounds, which were identified as resistomycin, a quinone-related antibiotic, and tetracenomycin D, an anthraquinone antibiotic, on the basis of spectral data of pure compounds. They demonstrated in vitro a potent cytotoxic activity against cell lines HMO2 (gastric adenocarcinoma) and HePG2 (hepatic carcinoma) and also exhibited weak antibacterial activities against Gram-positive and Gram-negative bacteria. Published in Russian in Bioorganicheskaya Khimiya, 2006, Vol. 32, No. 3, pp. 328–334. The text was submitted by the authors in English.     

Cytomorphological and molecular diversity in backcross-derived inbred lines of sunflower (Helianthus annuus L.).

A set of 250 distinct, stable, and uniform backcross-derived inbred lines were developed in sunflower through 5 interspecific cross combinations involving 4 wild diploid annual species (Helianthus argophyllus, H. petiolaris, H. annuus, and H. debilis). The presence of the wild-species genome in these inbred lines was confirmed through higher chromosome associations (tri- and quadrivalents) at diakinesis. Maximum structural rearrangements of chromosomes were observed in lines derived from H. petiolaris. Forty morphologically diverse inbred lines along with 2 controls were subjected to measurements of phenotypic and genetic distance using 118 simple sequence repeat (SSR) markers of known map location. A total of 204 alleles were identified and the number of alleles per locus varied between 2 and 5. There were 46 unique alleles and the number of unique alleles was highest in the lines derived from the cross involving H. petiolaris. The polymorphism information content (PIC) values ranged from 0.05 to 0.575. The pair-wise comparison values based on genetic dissimilarity estimates computed using molecular marker data varied between 0.143 and 0.486 among the 42 lines. The results indicate that the sunflower gene pool could benefit from introgression of novel alleles from the latent genetic diversity present in the wild species and particularly through exploitation of the diploid annual H. petiolaris.     

Variants of ST8SIA1 are associated with risk of developing multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system of unknown etiology with both genetic and environmental factors playing a role in susceptibility. To date, the HLA DR15/DQ6 haplotype within the major histocompatibility complex on chromosome 6p, is the strongest genetic risk factor associated with MS susceptibility. Additional alleles of IL7 and IL2 have been identified as risk factors for MS with small effect. Here we present two independent studies supporting an allelic association of MS with polymorphisms in the ST8SIA1 gene, located on chromosome 12p12 and encoding ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1. The initial association was made in a single three-generation family where a single-nucleotide polymorphism (SNP) rs4762896, was segregating together with HLA DR15/DQ6 in MS patients. A study of 274 family trios (affected child and both unaffected parents) from Australia validated the association of ST8SIA1 in individuals with MS, showing transmission disequilibrium of the paternal alleles for three additional SNPs, namely rs704219, rs2041906, and rs1558793, with p = 0.001, p = 0.01 and p = 0.01 respectively. These findings implicate ST8SIA1 as a possible novel susceptibility gene for MS.