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731.
732.
Nitrile metabolizing enzymes are of great industrial interest for the selective bio-transformation of nitriles and surface modification of synthetic polymers under mild reaction conditions. In the present work, isolated strain Amycolatopsis sp. IITR215 was cultivated in the bench top bioreactor for the recovery of maximum biomass of whole cell catalyst. Effect of different lyoprotectants was studied on nitrile metabolizing enzyme from Amycolatopsis sp. IITR215 in which sorbitol proved to be an efficient lyoprotectant. In physical and mechanical methods, only 30% activity was recovered while 85% activity was achieved in the enzymatic method using 2 g/l lysozyme. Very less activity was recovered during stationary phase when cells were grown in mineral base media containing 1 g/l yeast. Therefore, recovery of intracellular enzymes was enhanced by using different concentrations of sodium cholate and deoxycholate. 相似文献
733.
Photosynthetic properties of Cuscuta species, such as chloroplast ultrastructure, contents of chlorophylls, carotenoids, and
plastid proteins, photosystem and CO2 fixation activities, and photosynthetic genes composition are reviewed.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
734.
735.
S R Choudhury 《The journal of histochemistry and cytochemistry》1987,35(2):275-276
Isoelectric focusing (IEF) of soluble nonspecific esterases of rat kidney and testis exhibits an identical array of organophosphate-resistant cathodal isozymes. To ascertain whether such isozymes that focus at the same pI are also kinetically analogous, two isozymes, both focused at pI 7.2, were isolated, one from each organ, by elution from cut-out, unstained gel segments. Although the esterases of the whole soluble fraction of kidney and testis exhibited different kinetic properties and organophosphate susceptibility, no differences were observed with regard to the isozymes. Therefore, because of similar electrophoretic and kinetic behavior, the two isozymes can be regarded as phenotypic expressions of similar genetic products. 相似文献
736.
As the majority of human immunodeficiency virus (HIV) carriers are in asymptomatic stage for a long period of time, it is important to investigate the factors or surrogate markers for conversion from asymptomatic to symptomatic stage. Our study is designed to evaluate the relationship among virus isolation rate, anti-p17 antibody status and progression to AIDS. We studied anti-p17 antibody status along with virus isolation in 56 asymptomatic carriers and 46 AIDS cases. Progression to AIDS was markedly associated with high rate of virus isolation and loss of anti-p17 antibody. In order to know the meaning of loss of anti-p17 antibody during the clinical course, 15 anti-p17 antibody positive and 16 anti-p17 antibody negative cases were followed up prospectively for the development of AIDS. None of the anti-p17 antibody positive cases developed AIDS while 6 out of 16 anti-p17 negative cases developed AIDS during observation period (P < 0.05). Progression to AIDS was associated with loss of anti-p17 antibody. Identification of cases losing anti-p17 antibody in peripheral blood during asymptomatic period may help high-risk group who are in need of chemoprophylaxis. Moreover, study of anti-p17 antibody may be helpful in designing vaccine in future if it works as a neutralizing antibody to HIV in vivo. 相似文献
737.
Mr. Anwaruddin Choudhury 《American journal of primatology》1990,20(1):37-41
Data are presented on group size, composition, and reproduction of several hoolock gibbon groups studied in different areas of Assam, India, between 1986 and 1988. Presence of fewer young than reported in earlier studies signals a grim future for these gibbons unless strict conservation measures are undertaken. 相似文献
738.
Jennifer L. Franks Raquel C. Martinez-Chacin Xianxi Wang Rochelle L. Tiedemann Thomas Bonacci Rajarshi Choudhury Derek L. Bolhuis Taylor P. Enrico Ryan D. Mouery Jeffrey S. Damrauer Feng Yan Joseph S. Harrison M. Ben Major Katherine A. Hoadley Aussie Suzuki Scott B. Rothbart Nicholas G. Brown Michael J. Emanuele 《PLoS biology》2020,18(12)
The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase and critical regulator of cell cycle progression. Despite its vital role, it has remained challenging to globally map APC/C substrates. By combining orthogonal features of known substrates, we predicted APC/C substrates in silico. This analysis identified many known substrates and suggested numerous candidates. Unexpectedly, chromatin regulatory proteins are enriched among putative substrates, and we show experimentally that several chromatin proteins bind APC/C, oscillate during the cell cycle, and are degraded following APC/C activation, consistent with being direct APC/C substrates. Additional analysis revealed detailed mechanisms of ubiquitylation for UHRF1, a key chromatin regulator involved in histone ubiquitylation and DNA methylation maintenance. Disrupting UHRF1 degradation at mitotic exit accelerates G1-phase cell cycle progression and perturbs global DNA methylation patterning in the genome. We conclude that APC/C coordinates crosstalk between cell cycle and chromatin regulatory proteins. This has potential consequences in normal cell physiology, where the chromatin environment changes depending on proliferative state, as well as in disease.This study shows that the cell cycle E3 ubiquitin ligase APC/C is a regulator of several chromatin regulatory proteins, including the multivalent epigenetic reader and writer UHRF1. Perturbing UHRF1 ubiquitylation and degradation alters cell cycle and DNA methylation patterning, pointing to a key role for cell cycle degradation in shaping chromatin environments. 相似文献
739.
Anthony J. Szempruch Rajarshi Choudhury Zefeng Wang Stephen L. Hajduk 《RNA (New York, N.Y.)》2015,21(10):1781-1789
Trypanosomes possess a unique mitochondrial genome called the kinetoplast DNA (kDNA). Many kDNA genes encode pre-mRNAs that must undergo guide RNA-directed editing. In addition, alternative mRNA editing gives rise to diverse mRNAs and several kDNA genes encode open reading frames of unknown function. To better understand the mechanism of RNA editing and the function of mitochondrial RNAs in trypanosomes, we have developed a reverse genetic approach using artificial site-specific RNA endonucleases (ASREs) to directly silence kDNA-encoded genes. The RNA-binding domain of an ASRE can be programmed to recognize unique 8-nucleotide sequences, allowing the design of ASREs to cleave any target RNA. Utilizing an ASRE containing a mitochondrial localization signal, we targeted the extensively edited mitochondrial mRNA for the subunit A6 of the F0F1 ATP synthase (A6) in the procyclic stage of Trypanosoma brucei. This developmental stage, found in the midgut of the insect vector, relies on mitochondrial oxidative phosphorylation for ATP production with A6 forming the critical proton half channel across the inner mitochondrial membrane. Expression of an A6-targeted ASRE in procyclic trypanosomes resulted in a 50% reduction in A6 mRNA levels after 24 h, a time-dependent decrease in mitochondrial membrane potential (ΔΨm), and growth arrest. Expression of the A6-ASRE, lacking the mitochondrial localization signal, showed no significant growth defect. The development of the A6-ASRE allowed the first in vivo functional analysis of an edited mitochondrial mRNA in T. brucei and provides a critical new tool to study mitochondrial RNA biology in trypanosomes. 相似文献
740.
Photocontrol of Chlorophyll Loss in Papaya Leaf Discs 总被引:1,自引:0,他引:1
Both red and blue light pulses are separately shown to retarddark-stimulated chlorophyll loss of papaya leaf discs suggestingparticipation of phytochrome and blue light photoreceptors inregulating the pigment loss. The red light effect is fully reversibleby far-red light. The partial failure of far-red pulses to reversethe action of blue light suggests that blue light effect maynot be entirely through the phytochrome action. The apparentineffectiveness of continuous white light to check the chlorophyllloss is attributed to a balance of photooxidation and photoprotectionof the pigment. The interaction of blue light and kinetin at its different concentrationssuggests that the effect of interactions is additive. The bluelight effect in retarding chlorophyll loss is partly independentof the hormone level. (Received December 10, 1985; Accepted August 25, 1986) 相似文献