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51.
Gopinath S.C.B. Hilda A. Lakshmi priya T. Annadurai G. Anbu P. 《World journal of microbiology & biotechnology》2003,19(7):681-689
The fungus Geotrichum candidum was selected from isolates of oil-mill waste as a potent lipase producer. Factors affecting lipase production by the fungus G. candidum in yeast-extract-peptone medium have been optimized by using a Box–Behnken design with seven variables to identify the significant correlation between effects of these variables in the production of the enzyme lipase. The experimental values were found to be in accordance with the predicted values, the correlation coefficient is 0.9957. It was observed that the variables days (6), pH (7.0), temperature (30 °C), carbon (1.25%), nitrogen (2.0%), Tween (1.0%) and salt concentrations (0.5 mM) were the optimum conditions for maximum lipase production (87.7 LU/ml). The enzyme was purified to homogeneity with an apparent molecular mass of 32 kDa by SDS-PAGE. The optimum pH at 40 °C was 7.0 and the optimum temperature at pH 7.0 was 40 °C. The enzyme was stable within a pH range of 6.5 to 8.5 at 30 °C for 24 h. The enzyme activity was strongly inhibited by AgNO3, NiCl2, HgCl2, and EDTA. However, the presence of Ca2+ and Ba2+ ions enhanced the activity of the enzyme. 相似文献
52.
Gurusamy Balakrishnan Mohammed Ibrahim Piotr J. Mak Jessica Hata James R. Kincaid Thomas G. Spiro 《Journal of biological inorganic chemistry》2009,14(5):741-750
Time-resolved resonance Raman (RR) spectra are reported for hemoglobin (Hb) tetramers, in which the α and β chains are selectively
substituted with mesoheme. The Soret absorption band shift in mesoheme relative to protoheme permits chain-selective recording
of heme RR spectra. The evolution of these spectra following HbCO photolysis shows that the geminate recombination rates and
the yields are the same for the two chains, consistent with recent results on 15N-heme isotopomer hybrids. The spectra also reveal systematic shifts in the deoxyheme ν
4 and ν
Fe–His RR bands, which are anticorrelated. These shifts are resolved for the successive intermediates in the protein structure,
which have previously been determined from time-resolved UV RR spectra. Both chains show Fe–His bond compression in the immediate
photoproduct, which relaxes during the formation of the first intermediate, Rdeoxy (0.07 μs), in which the proximal F-helix is proposed to move away from the heme. Subsequently, the Fe–His bond weakens, more
so for the α chains than for the β chains. The weakening is gradual for the β chains, but is abrupt for the α chains, coinciding
with completion of the R–T quaternary transition, at 20 μs. Since the transition from fast- to slow-rebinding Hb also occurs
at 20 μs, the drop in the α chain ν
Fe–His supports the localization of ligation restraint to tension in the Fe–His bond, at least in the α chains. The mechanism is
more complex in the β chains. 相似文献
53.
Iszatty Ismail Tana Poorani Gurusamy Hema Ramachandran 《Preparative biochemistry & biotechnology》2017,47(4):388-396
Antibiofilm polymers have the ability to inhibit bacterial biofilm formation, which is known to occur ubiquitously in the environment and pose risks of infection. In this study, production of P(3HB-co-4HB) copolymer and antimicrobial yellow pigment from Cupriavidus sp. USMAHM13 are enhanced through medium optimization. Before the improvement of yellow pigment production, screening for the best additional supplement was performed resulting in high-yield yellow pigmentation using yeast extract with optimum concentration of 2?g/L. Effects of different concentrations of 1,4-butanediol, ammonium acetate, and yeast extract were studied using central composite design. Under optimal conditions, 53?wt% of polyhydroxyalkanoate (PHA) content, 0.35?g/L of pigment concentration, and 5.87?g/L of residual biomass were achieved at 0.56?wt% C of 1,4-butanediol, 1.14?g/L of ammonium acetate, and 2?g/L of yeast extract. Antibiofilm tests revealed that the yellow pigment coated on P(3HB-co-4HB) copolymer had significant effect on the inhibition of bacteria proliferation and colonization from 6?hr onward reaching 100% inhibition by 12?hr, hence effectively inhibiting the biofilm formation. 相似文献
54.
Overexpression of epidermal growth factor receptor (EGFR) is a common phenomenon observed in most cancers. Clinical treatment
of such cancer involves the use of chemotherapeutic agents such as gefitinib and erlotinib which are inhibitors of tyrosine
kinase (TK). These small molecules bind to the ATP-binding sites of the TK domain of EGFR. Our in silico analysis suggests that the TK domains of Drosophila and human EGFR are highly conserved. We therefore employed the Drosophila system to validate the in silico observations made with two important anticancer drugs. Since a large number of mutant flies are available, it was possible
to investigate the various components of the EGFR/Ras/Raf/ MAPK pathways and the phosphorylation status of diphosphorylated
extracellular signal-regulated kinase (dp-ERK1/2). These studies confirm the binding of the anilinoquinazolines to the Drosophila EGFR protein and modulation of its activity. Thus, Drosophila appears to be a robust and simple model system for screening newer anticancer drugs that act as TK inhibitors (TKIs).
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
Supplementary figures and tables pertaining to this article are available on the Journal of Biosciences Website at http://www.ias.ac.in/jbiosci/dec2008/pp731-742-suppl.pdf 相似文献
55.
Gurusamy K 《Biological trace element research》2007,118(3):191-206
Background The incidence of primary liver cancer varies between countries. Many of the etiological factors contributing to the geographical
variations in incidence are unknown. Development of hepatocellular carcinoma has been linked to levels of trace elements.
This review summarizes the evidence associating HCC with trace elements.
Methods MEDLINE, EMBASE, and CENTRAL databases were searched. Various inclusion and exclusion criteria were applied to select the
articles for inclusion. Data extraction was performed using a custom designed data extraction form.
Results A total of 12,344 references were identified. Duplicates, 1,597, were excluded. Clearly irrelevant references, 10,676, were
excluded through reading titles and abstracts. Some references (59) were excluded by applying the exclusion criteria. Twelve
studies including 646 patients and measuring iron content (8), copper content (11), zinc (9), and selenium (2) qualified for
the review. Although a meta-analysis was not possible due to heterogeneity between the studies, a clear pattern of distribution
of the trace elements was discernible.
Conclusion Iron and zinc content are lower in HCC than in surrounding tissues or normal controls. Copper content is lower in HCC than
in surrounding tissues and cirrhotic controls. Epidemiological and physiological reasons for the trace element alterations
should be further investigated. 相似文献
56.
Gurusamy Dhandapani Azhagiyamanavalan Lakshmi Prabha Mogilicherla Kanakachari Mullapudi Lakshmi Venkata Phanindra Narayanasamy Prabhakaran Sellamuthu Gothandapani Kethireddy Venkata Padmalatha Amolkumar U. Solanke Polumetla Ananda Kumar 《Biotechnology letters》2015,37(4):907-919
A novel stress tolerance cDNA fragment encoding GhDRIN1 protein was identified and its regulation was studied in cotton boll tissues and seedlings subjected to various biotic and abiotic stresses. Phylogenetic and conserved domain prediction indicated that GhDRIN1 was annotated with a hypothetical protein of unknown function. Subcellular localization showed that GhDRIN1 is localized in the chloroplasts. The promoter sequence was isolated and subjected to in silico study. Various cis-acting elements responsive to biotic and abiotic stresses and hormones were found. Transgenic tobacco seedlings exhibited better growth on amended MS medium and showed minimal leaf damage in insect bioassays carried out with Helicoverpa armigera larvae. Transgenic tobacco showed better tolerance to water-deficit and fast recovered upon rewatering. Present work demonstrated that GhDRIN1, a novel stress tolerance gene of cotton, positively regulates the response to biotic and abiotic stresses in transgenic tobacco. 相似文献
57.
Transgenic rice expressing a codon-modified synthetic CP4-EPSPS confers tolerance to broad-spectrum herbicide,glyphosate 总被引:3,自引:0,他引:3
58.
Redox activation of Ref-1 potentiates cell survival following myocardial ischemia reperfusion injury
A recent study showed that cardiac adaptation could potentiate translocation of thioredoxin-1 (Trx-1) into the nucleus, which then interacted with Ref-1, resulting in a survival signal. Here, we present evidence that such adaptation also causes nuclear translocation of Ref-1, which is almost completely inhibited when the hearts were pretreated with antisense Ref-1 that also abolished the cardioprotective adaptive response. Significant amounts of NFkappaB and Nrf2 were found to be associated with Ref-1 when the nuclear extract obtained from the left ventricle was immunoprecipitated with Ref-1. Such Ref-1-NFkappaB and Ref-1-Nrf2 interactions were significantly inhibited with antisense Ref-1. However, immunoprecipitation of nuclear extract with NFkappaB showed that the association of Trx-1 with NFkappaB is increased in the adapted heart, which was again significantly blocked by antisense Ref-1. Nrf2 was also associated with NFkappaB; however, such association appeared to be independent of Ref-1. In contrast, myocardial adaptation to ischemia inhibited the ischemia reperfusion-induced loss of Nrf2 from the nucleus, which was inhibited by antisense Ref-1. The nuclear translocation and activation of Ref-1 appeared to generate a survival signal as evidenced by the increased phosphorylation of Akt that was inhibited with antisense Ref-1. Finally, confocal microscopy confirmed the results of immunoblotting, clearly showing the nuclear translocation of Ref-1 and nuclear 3D colocalization of Ref-1 with NFkappaB in the adapted heart and its inhibition with antisense Ref-1. Our results show that PC potentiates a survival signal through the phosphorylation of Akt by causing nuclear translocation and activation of Ref-1, where significant interaction among NFkappaB and Ref-1, Trx-1, and Nrf2 appears to regulate Ref-1-induced survival signal. 相似文献
59.
Pravin Kumar R Manoj MN Kush A Annadurai RS 《Insect biochemistry and molecular biology》2007,37(6):635-640
In silico docking analysis reported here suggests that insect cellular cytoskeletal beta-actin could be the target of Azadirachtin A (Aza-the principle bioactive compound of neem seeds). The best docking energy of -40.09 kcal/mol at 8.73 A RMSD and predicted hydrogen bond between Arg210 and carboxymethyl group of Aza accompanied with seven hydrophobic interactions in the proposed binding site strongly support this hypothesis. This is of specific interest due to the non-affinity of Aza to mammalian beta-actins under the same set of conditions, although beta-actins across the species are highly conserved. Our results show that few scattered amino acid changes have caused significant steric hindrance in the binding pocket for mammalian beta-actin, causing a reverse orientation of Aza. These results suggest a model to support the recently observed biological effects caused by Aza in Drosophila cytoskeletal elements and explain why Aza is highly specific to insects than mammals. 相似文献
60.
MacKenzie SE Gurusamy GS Piórko A Strongman DB Hu T Wright JL 《Canadian journal of microbiology》2004,50(12):1069-1072
Several marine fungi collected from the waters of Prince Edward Island, Canada, were screened for the presence of natural products exhibiting antibacterial activity. Both broths and mycelia of these fungi were studied using the bioassay-guided chromatographic separation. The 4 fractions from the extract of mycelia of Corollospora lacera exhibited weak antibacterial activity and were analyzed further. From these fractions, 2 sterols (5 alpha,8 alpha-epidioxyergosterol and 22E,24R-ergosta-7,22-diene-3beta,5 alpha,6 beta-triol) and a 3:1 mixture of linoleic and oleic acids were isolated. The presence of ergosterol was confirmed in dichloromethane extracts of mycelia of every fungus in this study and this sterol was isolated from the extract of mycelium of Corollospora lacera. Two other known compounds (5-hydroxymethylfuran-2-carbaldehyde and bis(2-ethylhexyl) phthalate), were isolated from the dichloromethane extract of mycelium of Monodictys pelagica. The phthalate was reported in the literature as a metabolite isolated from the fungi, but in our study it was proven to be an artifact of the culturing and (or) extraction procedures rather than a true fungal metabolite. 相似文献