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21.
Decolorization and purification of crude protease from Rhizopus oryzae by activated charcoal and its electrophoretic analysis 总被引:1,自引:0,他引:1
Kaustav Aikat Tapas Kumar Maiti Bimal Chandra Bhattacharyya 《Biotechnology letters》2001,23(4):295-301
Activated charcoal decolorized and partially purified the protease from a crude extract of solid state fermentation of wheat bran by Rhizopus oryzae. Treatment for 5 min was sufficient. Depending on the initial colour intensity of crude, the charcoal to crude extract ratio could be optimized to achieve 90% decolorization, 85% enzyme recovery, and over a 3-fold purification, even up to 20-fold variation in batch size (from 1 ml to 20 ml crude extract). Decolorization followed the Freundlich and the Langmuir models, the Freundlich constant, n, being 2.74. Partial purification was confirmed by native PAGE and the protease band identified by gelatin-PAGE. SDS-PAGE showed the protease consisted of two sub-units (about 22 and 24 kDa).
List of symbols:
c
o, initial solute concentration in liquid before adsorption; c
*, equilibrium solute concentration in liquid after adsorption; k, empirical constant for Freundlich adsorption isotherm; U, unit of protease activity; v, volume of solution per unit weight of adsorbent. 相似文献
22.
Binding affinity and in vitro cytotoxicity of harmaline targeting different motifs of nucleic acids: An ultimate drug designing approach 下载免费PDF全文
Paromita Bhattacharjee Tapas Ghosh Sarita Sarkar Prateek Pandya Kakali Bhadra 《Journal of molecular recognition : JMR》2018,31(4)
The work focuses towards interaction of harmaline, with nucleic acids of different motifs by multispectroscopic and calorimetric techniques. Findings of this study suggest that binding constant varied in the order single‐stranded (ss) poly(A) > double‐stranded calf thymus (CT) DNA > double‐stranded poly(G)·poly(C) > clover leaf tRNAPhe. Prominent structural changes of ss poly(A), CT DNA, and poly(G)· poly(C) with concomitant induction of optical activity in the bound achiral alkaloid molecule was observed, while with tRNAPhe, very weak induced circular dichroism perturbation was seen. The interaction was predominantly exothermic, enthalpy driven, and entropy favored with CT DNA and poly(G)·poly(C), while it was entropy driven with poly(A) and tRNAPhe. Intercalated state of harmaline inside poly(A), CT DNA, and poly(G)·poly(C) was shown by viscometry, ferrocyanide quenching, and molecular docking. All these findings unequivocally pointed out preference of harmaline towards ss poly(A) inducing self‐structure formation. Furthermore, harmaline administration caused a significant decrease in proliferation of HeLa and HepG2 cells with GI50 of 28μM and 11.2μM, respectively. Nucleic acid fragmentation, cellular ultramorphological changes, decreased mitochondrial membrane potential, upregulation of p53 and caspase 3, generation of reactive oxygen species, and a significant increase in the G2/M population made HepG2 more prone to apoptosis than are HeLa cells. 相似文献
23.
Joseph Markowitz Tapas K. Mal Chunhua Yuan Nicholas B. Courtney Mitra Patel Andrew R. Stiff James Blachly Christopher Walker Ann‐Kathrin Eisfeld Albert de la Chapelle William E. Carson III 《Protein science : a publication of the Protein Society》2016,25(5):1069-1074
It was recently discovered that the NRAS isoform 5 (20 amino acids) is expressed in melanoma and results in a more aggressive cell phenotype. This novel isoform is responsible for increased phosphorylation of downstream targets such as AKT, MEK, and ERK as well as increased cellular proliferation. This structure report describes the NMR solution structure of NRAS isoform 5 to be used as a starting point to understand its biophysical interactions. The isoform is highly flexible in aqueous solution, but forms a helix‐turn‐coil structure in the presence of trifluoroethanol as determined by NMR and CD spectroscopy. 相似文献
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Kumar Abhiram Jha Tapas C Nag Shashi Wadhwa Tara Sankar Roy 《Journal of biosciences》2016,41(4):667-676
Light causes damage to the retina, which is one of the supposed factors for age-related macular degeneration in human. Some animal species show drastic retinal changes when exposed to intense light (e.g. albino rats). Although birds have a pigmented retina, few reports indicated its susceptibility to light damage. To know how light influences a cone-dominated retina (as is the case with human), we examined the effects of moderate light intensity on the retina of white Leghorn chicks (Gallus g. domesticus). The newly hatched chicks were initially acclimatized at 500 lux for 7 days in 12 h light: 12 h dark cycles (12L:12D). From posthatch day (PH) 8 until PH 30, they were exposed to 2000 lux at 12L:12D, 18L:6D (prolonged light) and 24L:0D (constant light) conditions. The retinas were processed for transmission electron microscopy and the level of expressions of rhodopsin, S- and L/M cone opsins, and synaptic proteins (Synaptophysin and PSD-95) were determined by immunohistochemistry and Western blotting. Rearing in 24L:0D condition caused disorganization of photoreceptor outer segments. Consequently, there were significantly decreased expressions of opsins and synaptic proteins, compared to those seen in 12L:12D and 18L:6D conditions. Also, there were ultrastructural changes in outer and inner plexiform layer (OPL, IPL) of the retinas exposed to 24L:0D condition. Our data indicate that the cone-dominated chick retina is affected in constant light condition, with changes (decreased) in opsin levels. Also, photoreceptor alterations lead to an overall decrease in synaptic protein expressions in OPL and IPL and death of degenerated axonal processes in IPL. 相似文献
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Johns P Pereira SL Leonard AE Mukerji P Shalwitz RA Dowlati L Phillips RR Bergana MS Holton JD Das T 《Current microbiology》2007,54(2):131-135
Adenosine 5′-diphosphoribose (ADP-ribose) has been identified as a significant contributor to the anti-cytotoxic activity
of Lactobacillus bulgaricus extracts. Although the biological activities associated with the administration of probiotic bacteria and components thereof
are sometimes attributed to the peptidoglycans that comprise a substantial portion of the Gram-positive bacterial cell wall,
we found that the beta-nicotine adenine dinucleotide (NAD) hydrolysis product ADP-ribose was a significant contributor to
the observed anti-cytotoxicity in our L. bulgaricus extracts. The ADP-ribose was isolated, identified, and quantitated by high performance liquid chromatography (HPLC) and by
nuclear magnetic resonance (NMR) spectroscopy. ADP-ribose levels as low as 5 mg/L exhibited a measurable inhibition of tumor
necrosis factor alpha (TNF-α) mediated cytotoxicity in an in vitro cell assay, whereas the ADP-ribose content of the L. bulgaricus extracts often exceeded 5 mg/g dry weight. 相似文献
29.
Beyond host-pathogen interactions: microbial defense strategy in the host environment 总被引:1,自引:0,他引:1
Fialho AM Stevens FJ Das Gupta TK Chakrabarty AM 《Current opinion in biotechnology》2007,18(3):279-286
Many extracellular pathogenic bacteria colonize human or animal bodies through evasion of the host immune system, a process called host-pathogen interaction. What happens when other intruders try to invade the same host and try to establish themselves in the same niche is largely unknown. In one well-studied case, Pseudomonas aeruginosa is known to secrete the protein azurin as a weapon against such invaders as cancers, parasites and viruses. The production of such weapons by pathogenic bacteria could provide important insights into how a pathogen responds in the post-colonization state to impede other intruders for its own survival. Moreover, these molecules might find use in the pharmaceutical industry as next-generation therapeutics. 相似文献
30.
Intermittent cyclic process for enhanced biological nutrient removal treating combined chemical laboratory wastewater 总被引:1,自引:0,他引:1
The aim of this work was to assess the efficacy for simultaneous enhanced removal of nitrogen and phosphorus including organics treating combined wastewater generated from a chemical laboratory using a bench-scale Intermittent Cyclic Process Bio-reactor (ICPBR). The performance efficacy indicated that the ICPBR system with solid retention time of 15 days achieved optimum efficiency with an overall removal of ammonia nitrogen (NH4-N), phosphorus (PO4-P), and chemical oxygen demand (COD) in the range, 83-92%, 74-93%, and 90-96%, respectively. 相似文献