Control of annual gonadal cycles in Indian songbirds

Abstract

Reproduction is a part of life cycle with great environmental dependence. In contrast to temperate avian species, which mostly breed during summer, the Indian songbirds have more flexible breeding programs and exhibit a spectrum of reproductive strategies with the breeding season scattered all over the year. Control of breeding cycles in the Indian songbirds, therefore, are broadly viewed in light of two strategies (i) birds showing strong photoperiodic component in regulation of reproductive and post-reproductive events (ii) birds that do not exhibit typical photoperiodic regulation indicating the involvement of an inherent rhythm of reproduction. Both circadian and circannual rhythms have been demonstrated to regulate annual gonadal cycles of Indian songbirds. While photoperiod continues to be a predominant proximate factor for timing of breeding in majority of Indian songbirds investigated so far, some studies reveal the role of non photoperiodic cues such as the food availability, temperature, rainfall, etc. in timing/modulating the timing of breeding. The conversion or non-conversion of thyroxine to triiodothyronine may act as a long or short photoperiod signal and may up or downregulate the synthesis and release of GnRH-I in hypothalamus, FSH and LH in anterior pituitary and gonadal steroids in gonads causing gonadal growth or regression, respectively.     

Role of Se(VI) in counteracting oxidative damage in <Emphasis Type="Italic">Brassica juncea</Emphasis> L. under Cr(VI) stress

Chromium (Cr) is considered to be one of the major environmental hazards and poses a threat to both plant and animal health. Selenium (Se), however, has been recognized as an essential micronutrient in plants. To understand the role of Se(VI) in oxidative stress management and regulation of antioxidative defence mechanism against heavy metal stress, the seedlings of Brassica juncea L. were raised in Petri plates containing nutrient media supplemented with only with Se(VI) and Cr(VI), or their combination. It was observed that of Cr(VI) causes an increase in reactive oxygen species (ROS) in the seedlings leading to oxidative stress. Histological studies using confocal and visible microscopy confirmed the biochemical results. Supplementation of up to 4 µM of Se(VI) to media containing 300 µM of Cr(VI) reduced the contents of ROS and increased enzymatic and non-enzymatic antioxidants in the seedlings. At a concentration of 6 µM, however, Se(VI) was toxic. The results suggested that at appropriate concentrations, the exogenous application of Se(VI) enabled the B. juncea seedlings to counteract the effects of Cr(VI), thereby increasing the resistance of plants.     

Estimation of Mineral and Trace Element Profile in Bubaline Milk Affected with Subclinical Mastitis

The milk samples from buffaloes of Murrah breed at mid lactation stage, reared at an organised dairy farm, were screened for subclinical mastitis based on bacteriological examination and somatic cell count following International Dairy Federation criteria. Milk samples from subclinical mastitis infected and healthy buffaloes were analysed to evaluate physicochemical alterations in terms of protein, fat, pH, electrical conductivity, chloride, minerals (sodium, potassium and calcium) and trace elements (iron, zinc, copper and selenium). In the present study, protein, fat, zinc, iron, calcium and selenium content was significantly lower (P < 0.001), while pH and electrical conductivity were significantly higher in mastitic milk as compared to normal milk. Concentration of electrolytes mainly sodium and chloride significantly increased with higher somatic cell count in mastitic milk and to maintain osmolality; potassium levels decreased proportionately. Correlation matrix revealed significantly positive interdependences of somatic cell count with pH, electrical conductivity, sodium and chloride. However, protein, fat, calcium and potassium were correlated negatively with elevated somatic cell count in mastitic milk. It is concluded that udder infections resulting in elevated somatic cells may alter the mineral and trace element profile of milk, and magnitude of changes may have diagnostic and prognostic value.     

1-Toluene-sulfonyl-3-[(3'-hydroxy-5'-substituted)-gamma-butyrolactone]-indoles: synthesis, COX-2 inhibition and anti-cancer activities

Indoles carrying a cyclic ester (gamma-butyrolactone) at C-3 position have been synthesized by the allylation of 3-indoleglyoxylate followed by iodocyclisation and the nucleophilic replacement of the iodo-group. Screening of these molecules for COX-2 inhibition and anti-cancer activities has identified compounds 10 and 11 as highly potent and selective for COX-2 as well as showing remarkable anti-cancer activities (better than that of indomethacin).     

Foldon-guided self-assembly of ultra-stable protein fibers

A common objective in protein engineering is the enhancement of the thermodynamic properties of recombinant proteins for possible applications in nanobiotechnology. The performance of proteins can be improved by the rational design of chimeras that contain structural elements with the desired properties, thus resulting in a more effective exploitation of protein folds designed by nature. In this paper, we report the design and characterization of an ultra-stable self-refolding protein fiber, which rapidly reassembles in solution after denaturation induced by harsh chemical treatment or high temperature. This engineered protein fiber was constructed on the molecular framework of bacteriophage P22 tail needle gp26, by fusing its helical core to the foldon domain of phage T4 fibritin. Using protein engineering, we rationally permuted the foldon upstream and downstream from the gp26 helical core and characterized gp26-foldon chimeras by biophysical analysis. Our data demonstrate that one specific protein chimera containing the foldon immediately downstream from the gp26 helical core, gp26(1-140)-F, displays the highest thermodynamic and structural stability and refolds spontaneously in solution following denaturation. The gp26-foldon chimeric fiber remains stable in 6.0 M guanidine hydrochloride, or at 80 degrees C, rapidly refolds after denaturation, and has both N and C termini accessible for chemical/biological modification, thereby representing an ideal platform for the design of self-assembling nanoblocks.     

Pygo2 expands mammary progenitor cells by facilitating histone H3 K4 methylation

Recent studies have unequivocally identified multipotent stem/progenitor cells in mammary glands, offering a tractable model system to unravel genetic and epigenetic regulation of epithelial stem/progenitor cell development and homeostasis. In this study, we show that Pygo2, a member of an evolutionarily conserved family of plant homeo domain–containing proteins, is expressed in embryonic and postnatal mammary progenitor cells. Pygo2 deficiency, which is achieved by complete or epithelia-specific gene ablation in mice, results in defective mammary morphogenesis and regeneration accompanied by severely compromised expansive self-renewal of epithelial progenitor cells. Pygo2 converges with Wnt/β-catenin signaling on progenitor cell regulation and cell cycle gene expression, and loss of epithelial Pygo2 completely rescues β-catenin–induced mammary outgrowth. We further describe a novel molecular function of Pygo2 that is required for mammary progenitor cell expansion, which is to facilitate K4 trimethylation of histone H3, both globally and at Wnt/β-catenin target loci, via direct binding to K4-methyl histone H3 and recruiting histone H3 K4 methyltransferase complexes.     

Identification, characterization and utilization of unigene derived microsatellite markers in tea (Camellia sinensis L.)

Background

Despite great advances in genomic technology observed in several crop species, the availability of molecular tools such as microsatellite markers has been limited in tea (Camellia sinensis L.). The development of microsatellite markers will have a major impact on genetic analysis, gene mapping and marker assisted breeding. Unigene derived microsatellite (UGMS) markers identified from publicly available sequence database have the advantage of assaying variation in the expressed component of the genome with unique identity and position. Therefore, they can serve as efficient and cost effective alternative markers in such species.

Results

Considering the multiple advantages of UGMS markers, 1,223 unigenes were predicted from 2,181 expressed sequence tags (ESTs) of tea (Camellia sinensis L.). A total of 109 (8.9%) unigenes containing 120 SSRs were identified. SSR abundance was one in every 3.55 kb of EST sequences. The microsatellites mainly comprised of di (50.8%), tri (30.8%), tetra (6.6%), penta (7.5%) and few hexa (4.1%) nucleotide repeats. Among the dinucleotide repeats, (GA)n.(TC)n were most abundant (83.6%). Ninety six primer pairs could be designed form 83.5% of SSR containing unigenes. Of these, 61 (63.5%) primer pairs were experimentally validated and used to investigate the genetic diversity among the 34 accessions of different Camellia spp. Fifty one primer pairs (83.6%) were successfully cross transferred to the related species at various levels. Functional annotation of the unigenes containing SSRs was done through gene ontology (GO) characterization. Thirty six (60%) of them revealed significant sequence similarity with the known/putative proteins of Arabidopsis thaliana. Polymorphism information content (PIC) ranged from 0.018 to 0.972 with a mean value of 0.497. The average heterozygosity expected (H _E ) and observed (H _o ) obtained was 0.654 and 0.413 respectively, thereby suggesting highly heterogeneous nature of tea. Further, test for IAM and SMM models for the UGMS loci showed excess heterozygosity and did not show any bottleneck operating in the tea population.

Conclusion

UGMS markers identified and characterized in this study provided insight about the abundance and distribution of SSR in the expressed genome of C. sinensis. The identification and validation of 61 new UGMS markers will not only help in intra and inter specific genetic diversity assessment but also be enriching limited microsatellite markers resource in tea. Further, the use of these markers would reduce the cost and facilitate the gene mapping and marker-aided selection in tea. Since, 36 of these UGMS markers correspond to the Arabidopsis protein sequence data with known functions will offer the opportunity to investigate the consequences of SSR polymorphism on gene functions.