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81.
Kousik?Chandra Venkatesh?Ramakrishnan Yogendra?Sharma K.?V.?R.?CharyEmail author 《Journal of biological inorganic chemistry》2011,16(1):81-95
Neuronal calcium sensor-1 (NCS-1) interacts with many membranes and cytosolic proteins, both in a Ca2+-dependent and in a Ca2+-independent manner, and its physiological role is governed by its N-terminal myristoylation. To understand the role of myristoylation
in altering Ca2+ response and other basic biophysical properties, we have characterized the Ca2+ filling pathways in both myristoylated (myr) and non-myristoylated (non-myr) forms of NCS-1. We have observed that Ca2+ binds simultaneously to all three active EF-hands in non-myr NCS-1, whereas in the case of myr NCS-1, the process is sequential,
where the second EF-hand is filled first, followed by the third and fourth EF-hands. In the case of myr NCS-1, the observed
sequential Ca2+ binding process becomes more prominent in the presence of Mg2+. Besides, the analysis of 15N-relaxation data reveals that non-myr NCS-1 is more dynamic than myr NCS-1. The overall molecular tumbling correlation time
increases by approximately 20% upon myristoylation. Comparing the apo forms of non-myr NCS-1 and myr NCS-1, we found the possibility
of existence of some substates, which are structurally closer to the holo form of the protein. There are more such substates
in the case of non-myr NCS-1 than in the case of the myr NCS-1, suggesting that the former accesses larger volumes of conformational
substates compared with the latter. Further, the study reveals that the possibility of Ca2+ binding simultaneously to different parts of the protein is more favourable in non-myr NCS-1 than in myr NCS-1. 相似文献
82.
A cytomorphologic diagnosis of tuberculous lymphadenitis by examination of needle aspirates was made in 560 of 1,471 cases of lymphadenopathy studied over two years. Cytologic features were categorized into four groups: epithelioid clusters with or without Langhans's giant cells without necrosis (32.14%), epithelioid clusters with or without Langhans's giant cells with necrosis (50.35%), occasional epithelioid cells without characteristic necrosis/giant cells (2.85%) and necrosis without epithelioid clusters or Langhans's giant cells (14.64%). While a diagnosis of tuberculous lymphadenitis was offered with confidence in the first two groups, constituting about 82.49% cases, aspirates from the third- and fourth-group patients were subjected to Ziehl-Neelsen staining for acid-fast bacilli, which was positive in 12.5% and 75.6% of cases, respectively. 相似文献
83.
84.
Bayer DM Mohan K Jayakumar K Manafi M Pavithra BH 《Journal of applied animal welfare science : JAAWS》2012,15(1):91-100
The objective of the study was to collect repeated, low-stress blood samples from the ulnar vein of chickens required for pharmacokinetic studies or hormonal assays. The study used 5 apparently healthy, unsexed, commercial broiler chickens about 6 weeks old and weighing 1.7-1.9 kg for serial sampling of blood. The study prepared the birds prior to cannulation and penetrated the catheter through the skin and into the lumen of the ulnar vein. The study successfully carried out serial blood samplings in 4 of 5 cannulated birds. Heparin (10%) solution maintained patency and prevented blood clot formation inside the cannula. However, the study found repeated clotting occurring in 1 bird. Cannula failed to maintain patency; the study could not carry out blood sampling properly, which was attributed to air embolism that might have occurred during catheter manipulation or repeated filling of cannula with heparin solution. The study observed no hematoma or inflammation at the site of cannulation. Owing to the advantages and to facilitate compliance with nonhuman animal welfare, this technique seems simple and efficient, allowing adoption for serial blood collection in chickens. 相似文献
85.
Zhu Y Mehta K Li C Xu GY Liu L Colak T Shenoy M Pasricha PJ 《American journal of physiology. Gastrointestinal and liver physiology》2012,302(1):G176-G181
We have previously shown that pancreatic sensory neurons in rats with chronic pancreatitis (CP) display increased excitability associated with a decrease in transient inactivating potassium currents (I(A)), thus accounting in part for the hyperalgesia associated with this condition. Because of its well known role in somatic hyperalgesia, we hypothesized a role for the nerve growth factor (NGF) in driving these changes. CP was induced by intraductal injection of trinitrobenzene sulfonic acid (TNBS) in rats. After 3 wk, anti-NGF antibody or control serum was injected intra-peritoneally daily for 1 wk. This protocol was repeated in another set of experiments in control rats (receiving intraductal PBS instead of TNBS). Pancreatic nociceptors labeled with the dye Dil were identified, and patch-clamp recordings were made from acutely dissociated DRG neurons. Sensory neurons from anti-NGF-treated rats displayed a lower resting membrane potential, increased rheobase, decreased burst discharges in response to stimulatory current, and decreased input resistance compared with those treated with control serum. Under voltage-clamp condition, neuronal I(A) density was increased in anti-NGF-treated rats compared with rats treated with control serum. However, anti-NGF treatment had no effect on electrophysiological parameters in neurons from control rats. The expression of Kv-associated channel or ancillary genes Kv1.4, 4.1, 4.2, 4.3, and DPP6, DPP10, and KCHIPs 1-4 in pancreas-specific nociceptors was examined by laser-capture microdissection and real-time PCR quantification of mRNA levels. No significant differences were seen among those. These findings emphasize a key role for NGF in maintaining neuronal excitability in CP specifically via downregulation of I(A) by as yet unknown mechanisms. 相似文献
86.
Marco Ventura Carlos Canchaya Andreas Tauch Govind Chandra Gerald F Fitzgerald Keith F Chater Douwe van Sinderen 《Microbiology and molecular biology reviews》2007,71(3):495-548
Actinobacteria constitute one of the largest phyla among bacteria and represent gram-positive bacteria with a high G+C content in their DNA. This bacterial group includes microorganisms exhibiting a wide spectrum of morphologies, from coccoid to fragmenting hyphal forms, as well as possessing highly variable physiological and metabolic properties. Furthermore, Actinobacteria members have adopted different lifestyles, and can be pathogens (e.g., Corynebacterium, Mycobacterium, Nocardia, Tropheryma, and Propionibacterium), soil inhabitants (Streptomyces), plant commensals (Leifsonia), or gastrointestinal commensals (Bifidobacterium). The divergence of Actinobacteria from other bacteria is ancient, making it impossible to identify the phylogenetically closest bacterial group to Actinobacteria. Genome sequence analysis has revolutionized every aspect of bacterial biology by enhancing the understanding of the genetics, physiology, and evolutionary development of bacteria. Various actinobacterial genomes have been sequenced, revealing a wide genomic heterogeneity probably as a reflection of their biodiversity. This review provides an account of the recent explosion of actinobacterial genomics data and an attempt to place this in a biological and evolutionary context. 相似文献
87.
Sandeep Dave H. Kitdorlang Dkhar Manvendra Pratap Singh Garima Gupta Vemika Chandra Sahil Mahajan Pawan Gupta 《The international journal of biochemistry & cell biology》2010,42(6):938-947
Stem bromelain is a proteolytic phytoprotein with a variety of therapeutic effects. Understanding its structural properties could provide insight into the mechanisms underlying its clinical utility. Stem bromelain was evaluated for its conformational and folding properties at the pH conditions it encounters when administered orally. It exists as a partially folded intermediate at pH 2.0. The conformational changes to this intermediate state were evaluated using fluorinated alcohols known to induce changes similar to those seen in vivo. Studies using circular dichroism, fluorescence emission spectroscopy, binding of the hydrophobic dye 1-anilino-8-naphthalene sulfonic acid and mass spectrometry indicate that treatment with 10–30% hexafluoroisopropanol induces the partially folded intermediate to adopt much of the native protein's secondary structure, but only a rudimentary tertiary structure, characteristic of the molten globule state. Addition of slightly higher concentrations of hexafluoroisopropanol caused transformation from an α-helix to a β-sheet and induced formation of a compact nonnative structure. This nonnative form was more inhibitory of cell survival than either the native or the partially folded intermediate forms, as measured by enhanced suppression of proliferative cues (e.g., extracellular-signal-regulated kinase) and initiation of apoptotic events. The nonnative form also showed better antitumorigenic properties, as evaluated using an induced two-stage mouse skin papilloma model. In contrast, the nonnative state showed only a fraction of the proteolytic activity of the native form. This study demonstrates that hexafluoroisopropanol can induce a conformational change in stem bromelain to a form with potentially useful therapeutic properties different from those of the native protein. 相似文献
88.
Rishiram Ramanan Krishnamurthi Kannan Nadimuthu Vinayagamoorthy Kunga Mohan Ramkumar Saravana Devi Sivanesan Tapan Chakrabarti 《Biotechnology and Bioprocess Engineering》2009,14(1):32-37
Carbonic anhydrase enzyme, one of the fastest known enzymes, remains largely unexplored in prokaryotes when compared to its
mammalian counterparts despite its ubiquity. In this study, the enzyme has been purified from Bacillus subtilis SA3 using sequential Sephadex G-75 chromatography, DEAE cellulose chromatography, and sepharose-4B-L-tyrosinesulphanilamide
affinity chromatography and characterized to provide additional insights into its properties. The apparent molecular mass
of carbonic anhydrase obtained by SDS-PAGE was found to be approximately 37 kDa. Isoelectric focusing of the purified enzyme
revealed an isoelectric point (pI) of around 6.1 when compared with marker. The presence of metal ions such as Zn2+, Co2+, Cu2+, Fe3+, Mg2+, and anion SO4− increased enzyme activity while strong inhibition was observed in the presence of Hg2+, Cl−, HCO3−, and metal chelator EDTA. The optimum pH and temperature for the enzyme were found to be 8.3 and 37°C, respectively. Enzyme
kinetics with p-nitrophenyl acetate as substrate at pH 8.3 and 37°C determined the Vmax and Km values of the enzyme to be 714.28 μmol/mg protein/min and 9.09 mM, respectively. The Ki value for acetazolamide was 0.22 mM, compared to 0.099 mM for sulphanilamide. The results from N-terminal amino acid sequencing
imply the purified protein is a putative beta-carbonic anhydrase with close similarities to CAs from plants, microorganisms. 相似文献
89.
Krishnendu Chandra Kaushik Ghosh Arnab K. Ojha Syed S. Islam 《Carbohydrate research》2009,344(16):2188-2194
A polysaccharide (PS-I) isolated from the aqueous extract of the unripe (green) tomatoes (Lycopersicon esculentum) consists of d-galactose, d-methyl galacturonate, d-arabinose, l-arabinose, and l-rhamnose. Structural investigation of the polysaccharide was carried out using total acid hydrolysis, methylation analysis, periodate oxidation study, and NMR studies (1H, 13C, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC). On the basis of above-mentioned experiments the structure of the repeating unit of the polysaccharide (PS-I) was established as:
相似文献
Full-size image (8K)
90.
Singh AR Joshi S Arya R Kayastha AM Srivastava KK Tripathi LM Saxena JK 《Parasitology international》2008,57(3):354-361
5' EST from filarial gene database has been subjected to 3' rapid amplification of cDNA ends (RACE), semi-nested PCR and PCR to obtain full-length cDNA of Brugia malayi. Full-length hexokinase gene was obtained from cDNA using gene specific primers. The elicited PCR product was cloned, sequenced and expressed as an active enzyme in Escherichia coli. Sequence analysis of B. malayi hexokinase (BmHk) revealed 59% identity with nematode Caenorhabditis elegans but low similarity with all other available hexokinases including human. BmHk, an apparent tetramer with subunit molecular mass of 72 kDa, was able to phosphorylate glucose, fructose, mannose, maltose and galactose. The Km values for glucose, fructose and ATP were found to be 0.035+/-0.005, 75+/-0.3 and 1.09+/-0.5 mM respectively. BmHk was strongly inhibited by ADP, glucosamine, N-acetyl glucosamine and mannoheptulose. The recombinant enzyme was found to be activated by glucose-6-phosphate. ADP exhibited noncompetitive inhibition with the substrate glucose (Ki=0.55 mM) while, mixed type of inhibition was observed with inorganic pyrophosphate (PPi) when ATP was used as substrate (Ki=9.92 microM). The enzyme activity is highly dependent on maintenance of free sulfhydryl groups. CD analysis indicated that BmHk is composed of 37% alpha-helices and 26% beta-sheets. The observed differences in kinetic properties of BmHk as compared to host enzyme may facilitate designing of specific inhibitors against BmHk. 相似文献