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121.
122.
Distribution of the flavohaemoglobin, HMP, between periplasm and cytoplasm in Escherichia coli 总被引:1,自引:0,他引:1
Subhash G. Vasudevan Pan Tang Nicholas E. Dixon Robert K. Poole 《FEMS microbiology letters》1995,125(2-3):219-224
Abstract The subcellular distribution of the soluble flavohaemoglobin (HMP) of Escherichia coli has been determined. Cells over-expressing HMP from the cloned hmp gene on a multicopy plasmid were fractionated by osmotic shock and lysozyme treatment. Spectral analysis of subcellular fractions showed the CO-binding haemoprotein to be cytoplasmic. However, Western blotting using antibody raised to purified HMP revealed approximately 30% of the protein to be periplasmic in the over-expressing strain. Western analysis also revealed substantial levels of periplasmic HMP in a strain expressing only chromosomally encoded protein but none in an hmp mutant. The results are discussed in relation to protein function and the similar distribution reported for Vitreoscilla globin. 相似文献
123.
Glutamate-Stimulated, Guanine Nucleotide-Mediated Phosphoinositide Turnover in Astrocytes Is Inhibited by Cyclic AMP 总被引:3,自引:3,他引:0
Patricia L. Robertson George R. Bruno Subhash C. Datta 《Journal of neurochemistry》1990,55(5):1727-1733
The potential for cross-talk between the adenyl cyclase and phosphoinositide (PPI) lipid second messenger system was investigated in astrocytes cultured from neonatal rat brain. Glutamate-stimulated PPI turnover, measured by the formation of total inositol phosphates from myo-[3H]inositol-labeled lipids, was inhibited in a concentration-dependent manner by the elevation of intracellular cyclic AMP levels produced either by stimulation of the isoproterenol receptor linked to adenyl cyclase or by its direct activation by forskolin. N6,2'-O-Dibutyryl cyclic AMP, an analogue that can also activate cyclic AMP-dependent kinase, inhibited glutamate-stimulated PPI turnover in a concentration-dependent manner as well, a result suggesting that cyclic AMP-dependent kinase is involved in mediating the inhibition. Inclusion of an inhibitor of cyclic AMP-dependent kinase, 1-(5-isoquinolinesulfonyl)-2 methylpiperazine dihydrochloride or N-(2-guanidinoethyl)-5-isoquinolinesulfonamide hydrochloride, blocked the cyclic AMP-mediated inhibition in a concentration-dependent manner, a finding further supporting this hypothesis. The site of inhibition of the phosphoinositol lipid pathway by cyclic AMP was probed using a digitonin-permeabilized cell system. Guanosine 5'-O-(3-thiotriphosphate), a nonhydrolyzable analogue of GTP, stimulated PPI turnover and potentiated glutamate-stimulated PPI turnover, and guanosine 5'-O-(3-thiodiphosphate) inhibited glutamate-stimulated PPI turnover in these cells, results providing evidence that glutamate receptors are coupled to phospholipase C by a guanine nucleotide binding protein in astrocytes.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
124.
Pigment as well as isozyme variations were observed among aspen (Populus tremuloides Michx.) plants regenerated from callus cultures. Out of more than 600 plantlets, two chimeric plants (one with green base and two albino shoots and the other with an albino shoot) were produced. Callus derived from albino shoots produced albino as well as chimeric plants when transferred to shoot inducing medium. Isozyme patterns of 119 plants were examined by starch gel electrophoresis. Thirty plants showed variation in shikimic dehydrogenase isozyme and 41 in isocitric dehydrogenase. Variation was also observed in malate dehydrogenase and phosphoglucose isomerase. No variation was seen in 6-phosphogluconate dehydrogenase. Pigment variation was not associated with any isozyme changes.Abbreviations BA
6-benzyladenine
- IBA
indole-3-butyric acid
- GD
Gresshoff & Doy medium
- WPM
woody plant medium
- SKD
shikimic dehydrogenase
- IDH
isocitric dehydrogenase
- MDH
malate dehydrogenase
- PGI
phosphoglucose isomerase
- 6-PGD
6-phosphogluconate dehydrogenase 相似文献
125.
Thomas Rausch Subhash C. Minocha Willy Hilgenberg Günter Kahl 《Physiologia plantarum》1985,63(4):335-344
The in vivo metabolism of L-tryptophan in wound-activated and Agrobacterium tumefaciens , strain C 58, transformed tissues of white potato tubers ( Solanum tuberosum L. cv. Saskia) was investigated. The following metabolites of L-tryptophan were identified in both tissues by co-chromatography with authentic standards in several thinlayer chromotography (TLC) and high pressure liquid chromatographic (HPLC) systems: indole-3-acetic acid (IAA), indole-3-acetaldehyde, indole-3-ethanol, indole-3-acetamide and tryptamine. Labelled indole-3-acetaldoxime was only found in transformed tissue. Crown gall tissue generally incorporated [14 C]-L-tryptophan into precursors of IAA at a distinctly higher rate than did wound tissue. Tryptamine and indole-3-ethanol accumulated about ten-fold more label in crown gall cells than in cells from wounded tissue. The incorporation of radioactivity into indole-3-acetamide as determined by 2 consecutive TLC systems followed by HPLC analysis was rather low, though consistently observed in both tissues. An indole-3-acetamide hydrolyzing enzyme, the putative product of gene 2 on the T-DNA, could be extracted from the transformed tissue only. The indole-3-ethanol level was 4.3 nmol (g dry weight)−1 and 41 nmol (g dry weight)−1 for wounded tissue and primary crown gall tissue, respectively, as determined by HPLC with a [14 C]-labelled internal standard. The experiments are critically discussed in relation to recent reports on a T-DNA encoded enzyme of IAA biosynthesis in crown gall tumors. 相似文献
126.
Quantification of photonic localization properties of targeted nuclear mass density variations: Application in cancer‐stage detection 下载免费PDF全文
Peeyush Sahay Aditya Ganju Huda M. Almabadi Hemendra M. Ghimire Murali M. Yallapu Omar Skalli Meena Jaggi Subhash C. Chauhan Prabhakar Pradhan 《Journal of biophotonics》2018,11(5)
Light localization is a phenomenon which arises due to the interference effects of light waves inside a disordered optical medium. Quantification of degree light localization in optical media is widely used for characterizing degree of structural disorder in that media. Recently, this light localization approach was extended to analyze structural changes in biological cell like heterogeneous optical media, with potential application in cancer diagnostics. Confocal fluorescence microscopy was used to construct “optical lattices,” which represents 2‐dimensional refractive index map corresponding to the spatial mass density distribution of a selected molecule inside the cell. The structural disorder properties of the selected molecules were evaluated numerically using light localization strength in these optical lattices, in a single parameter called “disorder strength.” The method showed a promising potential in differentiating cancerous and non‐cancerous cells. In this paper, we show that by quantifying submicron scale disorder strength in the nuclear DNA mass density distribution, a wide range of control and cancerous breast and prostate cells at different hierarchy levels of tumorigenicity were correctly distinguished. We also discuss how this photonic technique can be used in examining tumorigenicity level in unknown prostate cancer cells, and potential to generalize the method to other cancer cells. 相似文献
127.
Hadi Hasan Choudhary Pratik Narain Srivastava Subhash Singh Kota Arun Kumar Satish Mishra 《International journal for parasitology》2018,48(3-4):203-209
In Plasmodium, the shikimate pathway is a potential target for malaria chemotherapy owing to its absence in the mammalian host. Chorismate, the end product of this pathway, serves as a precursor for aromatic amino acids, Para-aminobenzoic acid and ubiquinone, and is synthesised by Chorismate synthase (CS). Therefore, it follows that the Cs locus may be refractory to genetic manipulation. By utilising a conditional mutagenesis system of yeast Flp/FRT, we demonstrate an unexpectedly dispensable role of CS in Plasmodium. Our studies reiterate the need to establish an obligate reliance on Plasmodium metabolic enzymes through genetic approaches before their selection as drug targets. 相似文献
128.
Spatiotemporal dynamics and genome‐wide association analysis of desiccation tolerance in Drosophila melanogaster 下载免费PDF全文
Subhash Rajpurohit Eran Gefen Alan O. Bergland Dmitri A. Petrov Allen G. Gibbs Paul S. Schmidt 《Molecular ecology》2018,27(17):3525-3540
Water availability is a major environmental challenge to a variety of terrestrial organisms. In insects, desiccation tolerance varies predictably over spatial and temporal scales and is an important physiological determinant of fitness in natural populations. Here, we examine the dynamics of desiccation tolerance in North American populations of Drosophila melanogaster using: (a) natural populations sampled across latitudes and seasons; (b) experimental evolution in field mesocosms over seasonal time; (c) genome‐wide associations to identify SNPs/genes associated with variation for desiccation tolerance; and (d) subsequent analysis of patterns of clinal/seasonal enrichment in existing pooled sequencing data of populations sampled in both North America and Australia. A cline in desiccation tolerance was observed, for which tolerance exhibited a positive association with latitude; tolerance also varied predictably with culture temperature, demonstrating a significant degree of thermal plasticity. Desiccation tolerance evolved rapidly in field mesocosms, although only males showed differences in desiccation tolerance between spring and autumn collections from natural populations. Water loss rates did not vary significantly among latitudinal or seasonal populations; however, changes in metabolic rates during prolonged exposure to dry conditions are consistent with increased tolerance in higher latitude populations. Genome‐wide associations in a panel of inbred lines identified twenty‐five SNPs in twenty‐one loci associated with sex‐averaged desiccation tolerance, but there is no robust signal of spatially varying selection on genes associated with desiccation tolerance. Together, our results suggest that desiccation tolerance is a complex and important fitness component that evolves rapidly and predictably in natural populations. 相似文献
129.
Sven Ruf Mahanandeesha Siddappa Hallur Nisha K. Anchan Indu N. Swamy Karthikai Raj Murugesan Sayantani Sarkar Lokesh Kananti Narasimhulu V.P. Rama Kishore Putta Shama Shaik Devaraj Venkatapura Chandrasekar Vishal Subhash Mane Sanjay Venkatachalapathi Kadnur Juluri Suresh Ravi Kanth Bhamidipati Manvi Singh Raghunadha Reddy Burri Rajendra Kristam Herman Schreuder Sridharan Rajagopal 《Bioorganic & medicinal chemistry letters》2018,28(5):922-925
Nicotinamide N-methyltransferase (NNMT) has been linked to obesity and diabetes. We have identified a novel nicotinamide (NA) analog, compound 12 that inhibited NNMT enzymatic activity and reduced the formation of 1-methyl-nicotinamide (MNA), the primary metabolite of NA by ~80% at 2?h when dosed in mice orally at 50?mg/kg. 相似文献
130.
Glutaraldehyde cross‐linking increases the stability of Lumbricus terrestris erythrocruorin 下载免费PDF全文
Athul Rajesh Devon Zimmerman Kyle Spivack Osheiza Abdulmalik Jacob Elmer 《Biotechnology progress》2018,34(2):521-528
Since donated red blood cells must be constantly refrigerated, they are not available in remote areas and battlefields. We have previously shown that the hemoglobin of the earthworm Lumbricus terrestris (LtEc) is an effective and safe substitute for donated blood that is stable enough to be stored for long periods at the relatively high temperatures that may be encountered in remote areas. The goal of this study was to further increase the thermal stability of LtEc by covalently cross‐linking LtEc with glutaraldehyde (gLtEc). Our results show that the melting temperatures of the gLtEc samples steadily increase as the molar ratio of glutaraldehyde to heme increases (from Tm = 57°C for native LtEc up to Tm = 68°C at a ratio of 128:1). In addition, while native LtEc is susceptible to subunit dissociation at alkaline pH (8–10), cross‐linking with glutaraldehyde completely prevents dissociation of gLtEc at pH 10. Increasing the molar ratio of glutaraldehyde:heme also significantly increased the oxygen affinity of gLtEc, but this effect was decreased by cross‐linking gLtEc in the deoxygenated T state. Finally, while gLtEc samples cross‐linked at low G:H ratios (e.g., 2:1) exhibited slight increases in oxidation rate in Tris buffer, no significant difference in oxidation rate was observed between native LtEc and the gLtEc samples in Ringer's Solution, which contains antioxidants. Overall, cross‐linking LtEc with glutaraldehyde significantly increases its thermal and structural stability without any loss of function, making gLtEc an attractive blood substitute for deployment in remote areas and battlefields. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:521–528, 2018 相似文献