Inactivation of guanosine cyclic 3',5'-monophosphate dependent protein kinase from bovine lung by o-phthalaldehyde

Guanosine cyclic 3',5'-monophosphate (cGMP) dependent protein kinase is inactivated by o-phthalaldehyde. The loss of phosphotransferase activity following treatment with o-phthalaldehyde was rapid, and the second-order rate constant at 25 degrees C and pH 7.3 was 35 M-1 s-1. The inactivation reaction did not follow saturation kinetics. The cGMP-dependent protein kinase was protected from inactivation by its substrates, MgATP and Ser-peptide. Fluorescence excitation and emission spectroscopic data showed that an isoindole derivative was formed following the reaction between cGMP-dependent protein kinase and o-phthalaldehyde. Four moles of isoindole per mole of the cGMP-dependent protein kinase dimer was formed following complete inactivation by o-phthalaldehyde. In the absence of cGMP, the protein kinase lost only 50% of its cGMP binding activity while there was almost a complete loss of its phosphotransferase activity. Studies in the presence of 20 microM cGMP, however, showed that about 2 mol of isoindole groups per mole of the protein kinase dimer was formed following complete inactivation by o-phthalaldehyde. The second-order rate constant for inactivation of cGMP-dependent protein kinase by o-phthalaldehyde in the presence of 20 microM cGMP was 40 M-1 s-1. Fluorescence measurements of samples containing inactivated, iodoacetamide-modified, or 5'-[p-(fluorosulfonyl)benzoyl]adenosine-modified, cGMP-dependent protein kinase and o-phthalaldehyde showed that the intensity of fluorescence in each case was about 50% of that obtained from unmodified, active cGMP-dependent protein kinase and o-phthalaldehyde.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification of mirtrons in rice using MirtronPred: a tool for predicting plant mirtrons

Studies from flies and insects have reported the existence of a special class of miRNA, called mirtrons that are produced from spliced-out introns in a DROSHA-independent manner. The spliced-out lariat is debranched and refolded into a stem-loop structure resembling the pre-miRNA, which can then be processed by DICER into mature ~21 nt species. The mirtrons have not been reported from plants. In this study, we present MirtronPred, a web based server to predict mirtrons from intronic sequences. We have used the server to predict 70 mirtrons in rice introns that were put through a stringent selection filter to shortlist 16 best sequences. The prediction accuracy was subsequently validated by northern analysis and RT-PCR of a predicted Os-mirtron-109. The target sequences for this mirtron were also found in the rice degradome database. The possible role of the mirtron in rice regulon is discussed. The MirtronPred web server is available at http://bioinfo.icgeb.res.in/mirtronPred.     

Isolation of auxotrophic mutants in support of ammonia assimilation via glutamine synthetase in Methanobacterium ivanovii

Various enzymes involved in the initial metabolic pathway for ammonia assimilation by Methanobacterium ivanovii were examined. M. ivanovii showed significant activity of glutamine synthetase (GS). Glutamate synthase (GOGAT) and alanine dehydrogenase (ADH) were present, wheras, glutamate dehydrogenase (GDH) was not detected. When M. ivanovii was grown with different levels of NH ₊ ⁴ (i.e. 2, 20 or 200 mM), GS, GOGAT and ADH activities varied in response to NH ₊ ⁴ concentration. ADH was not detected at 2 mM level, but its activity increased with increased levels of NH ₊ ⁴ in the medium. Both GS and GOGAT activities increased with decreasing concentrations of NH ₊ ⁴ and were maximum when ammonia was limiting, suggesting that at low NH ₊ ⁴ levels, GS and GOGAT are responsible for ammonia assimilation and at higher NH ₊ ⁴ levels, ADH might play a role. Metabolic mutants of M. ivanovii that were auxotrophic for glutamine were obtained and analyzed for GS activity. Results indicate two categories of mutants: i) GS-deficient auxotrophic mutants and ii) GS-impaired auxotrophic mutants.Abbreviations GS Glutamine synthetase - GOGAT glutamate synthase - GDH glutamate dehydrogenase - ADH alanine dehydrogenase     

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.     

Androgen receptor status predicts response to chemotherapy, not risk of breast cancer in Indian women

Voltage gated potassium channels have been extensively studied in relation to cancer. In this review, we will focus on the role of two potassium channels, Ether à-go-go (Eag), Human ether à-go-go related gene (HERG), in cancer and their potential therapeutic utility in the treatment of cancer. Eag and HERG are expressed in cancers of various organs and have been implicated in cell cycle progression and proliferation of cancer cells. Inhibition of these channels has been shown to reduce proliferation both in vitro and vivo studies identifying potassium channel modulators as putative inhibitors of tumour progression. Eag channels in view of their restricted expression in normal tissue may emerge as novel tumour biomarkers.     

Synthesis and evaluation of antitubercular activity of glycosyl thio- and sulfonyl acetamide derivatives

A series of glycosyl thioacetamide and glycosyl sulfonyl acetamide derivatives have been prepared following a convenient reaction protocol and evaluated for their antitubercular activity against Mycobacterium tuberculosis H₃₇Rv. Amongst 32 compounds evaluated 3 compounds were effective in inhibiting mycobacterial growth at MIC of 6.25 μg/mL, 6 compounds at MIC of 3.125 μg/mL and 1 compound at MIC of 1.56 μg/mL. All active compounds were found nontoxic in Vero cell lines and mice bone marrow macrophages.     

Flavonoids from Dodonaea viscosa

An investigation of Dodonaea viscosa afforded a new flavonoid having an isoprenoid side chain along with the seven known flavonoids: 5-hydroxy-3,6,     

Cribriform plate of ethmoid, olfactory bulb and olfactory acuity in forty species of bats

Relationships between the cribriform plate of the ethmoid, the olfactory bulb, and olfactory acuity were explored using material from 13 of the 17 bat families. All megachiropteran cribriform plates were entirely perforated. In contrast, microchiropteran plates showed distinct perforated portions dorsally and nonperforated portions ventrally. The plates of frugivorous species had more foramina than those of insectivorous ones. Bats with mixed dietary habits were intermediate. Our data suggest that the Chilonycterinae were originally frugivorous, and have only secondarily reverted to an insectivorous diet. Trend analyses show that wherever dietary preference appears to favor a more acute sense of smell, bulb diameter tends to be larger. In general, frugivorous bats tend to have bulbs exceeding 2 mm in diameter; insectivorous bats tend to have bulb diameters of 2 mm or less. The number of foramina in the plates and total cribriform plate area tends to increase as a function of bulb area, but the plate area the foramina occupied increases as a function of bulb volume. The ratio of the size of the bulb to the size of the cerebral hemisphere does not predict olfactory acuity in bats.     

Reduced dimensionality (4,3)D-hnCOCANH experiment: an efficient backbone assignment tool for NMR studies of proteins

Sequence specific resonance assignment of proteins forms the basis for variety of structural and functional proteomics studies by NMR. In this context, an efficient standalone method for rapid assignment of backbone (¹H, ¹⁵N, ¹³C^α and ¹³C′) resonances of proteins has been presented here. Compared to currently available strategies used for the purpose, the method employs only a single reduced dimensionality experiment—(4,3)D-hnCOCANH and exploits the linear combinations of backbone (¹³C^α and ¹³C′) chemical shifts to achieve a dispersion relatively better compared to those of individual chemical shifts (see the text). The resulted increased dispersion of peaks—which is different in sum (CA + CO) and difference (CA ? CO) frequency regions—greatly facilitates the analysis of the spectrum by resolving the problems (associated with routine assignment strategies) arising because of degenerate amide ¹⁵N and backbone ¹³C chemical shifts. Further, the spectrum provides direct distinction between intra- and inter-residue correlations because of their opposite peak signs. The other beneficial feature of the spectrum is that it provides: (a) multiple unidirectional sequential (i→i + 1) ¹⁵N and ¹³C correlations and (b) facile identification of certain specific triplet sequences which serve as check points for mapping the stretches of sequentially connected HSQC cross peaks on to the primary sequence for assigning the resonances sequence specifically. On top of all this, the F ₂–F ₃ planes of the spectrum corresponding to sum (CA + CO) and difference (CA ? CO) chemical shifts enable rapid and unambiguous identification of sequential HSQC peaks through matching their coordinates in these two planes (see the text). Overall, the experiment presented here will serve as an important backbone assignment tool for variety of structural and functional proteomics and drug discovery research programs by NMR involving well behaved small folded proteins (MW < 15 kDa) or a range of intrinsically disordered proteins.