Perchloric acid extracts of radiation-induced fibrosarcoma (RIF-1) tumors grown in mice have been analyzed by multinuclear NMR spectroscopy and by various chromatographic methods. This analysis has permitted the unambiguous assignment of the 31P resonances observed in vivo to specific phosphorus-containing metabolites. The region of the in vivo spectra generally assigned to sugar phosphates has been found in RIF-1 tumors to contain primarily phosphorylethanolamine and phosphorylcholine rather than glycolytic intermediates. Phosphocreatine was observed in extracts of these tumor cells grown in culture as well as in the in vivo spectra, indicating that at least some of the phosphocreatine observed in vivo arises from the tumor itself and not from normal tissues. In the 31P-NMR spectra of the perchloric acid extract, resonances originating from purine and pyrimidine nucleoside di- and triphosphate were resolved. HPLC analyses of the nucleotide pool indicate that adenine derivatives were the most abundant components, but other nucleotides were present in significant amounts. The 1H and 13C resonance assignments of the majority of metabolites present in RIF-1 extracts have also been made. Of particular importance is the ability to observe lactate, the levels of which may provide a noninvasive measure of glycolysis in these cells in both the in vivo and in vitro states. In addition, the aminosulfonic acid, taurine, was found in high levels in the tumor extracts. 相似文献
We previously identified Xenopus Pat1a (P100) as a member of the maternal CPEB RNP complex, whose components resemble those of P-(rocessing) bodies, and which is implicated in translational control in Xenopus oocytes. Database searches have identified Pat1a proteins in other vertebrates, as well as paralogous Pat1b proteins. Here we characterize Pat1 proteins, which have no readily discernable sequence features, in Xenopus oocytes, eggs, and early embryos and in human tissue culture cells. xPat1a and 1b have essentially mutually exclusive expression patterns in oogenesis and embryogenesis. xPat1a is degraded during meiotic maturation, via PEST-like regions, while xPat1b mRNA is translationally activated at GVBD by cytoplasmic polyadenylation. Pat1 proteins bind RNA in vitro, via a central domain, with a preference for G-rich sequences, including the NRAS 5′ UTR G-quadruplex-forming sequence. When tethered to reporter mRNA, both Pat proteins repress translation in oocytes. Indeed, both epitope-tagged proteins interact with the same components of the CPEB RNP complex, including CPEB, Xp54, eIF4E1b, Rap55B, and ePAB. However, examining endogenous protein interactions, we find that in oocytes only xPat1a is a bona fide component of the CPEB RNP, and that xPat1b resides in a separate large complex. In tissue culture cells, hPat1b localizes to P-bodies, while mPat1a-GFP is either found weakly in P-bodies or disperses P-bodies in a dominant-negative fashion. Altogether we conclude that Pat1a and Pat1b proteins have distinct functions, mediated in separate complexes. Pat1a is a translational repressor in oocytes in a CPEB-containing complex, and Pat1b is a component of P-bodies in somatic cells. 相似文献
Screening of fifteen nutrients belonging to four categories, viz., carbon, nitrogen, salt and complex organic sources was carried out using Plackett-Burman design for the production of thermostable #-amylase and pullulanase by Clostridium thermosulfurogenes SV2 in solid-state fermentation (SSF). This design involves screening of up to `nу' variables in just `n' number of experiments. Regression co-efficients and t-values were calculated by subjecting the experimental data to statistical analysis. Lactose, diammonium hydrogen phosphate, calcium chloride and casein hydrolysate showed higher regression co-efficients in the biomass formation. Among the fifteen nutrients screened, based on their performance in terms of product promoting ability, availability and cost, magnesium chloride, potato starch, ferrous sulphate, pearl millet flour and corn steep liquor were identified as most effective and, therefore, selected for inclusion in further optimization studies. 相似文献
In the present study the potentials of aqueous extracts of the two plants, neem (Azadirachta indica) and Tulsi (Ocimum sanctum) were examined in alleviating arsenic toxicity in rice (Oryza sativa L.) plants grown in hydroponics. Seedlings of rice grown for 8 days in nutrient solution containing 50 μM sodium arsenite showed decline in growth, reduced biomass, altered membrane permeability and increased production of superoxide anion (O2·−), H2O2 and hydroxyl radicals (·OH). Increased lipid peroxidation marked by elevated TBARS (thiobarbituric acid reactive substances) level, increased protein carbonylation, alterated levels of ascorbate, glutathione and increased activities of enzymes SOD (superoxide dismutase), CAT (catalase), APX (ascorbate peroxidase) and GPX (glutathione peroxidase) were noted in the seedlings on As treatment. Exogenously added leaf aqueous extracts of Azadirachta indica (0.75 mg mL−1, w/v) and Ocimum sanctum (0.87 mg mL−1, w/v) in the growth medium considerably alleviated As toxicity effects in the seedlings, marked by reduced As uptake, restoration of membrane integrity, reduced production of ROS, lowering oxidative damage and restoring the levels of ascorbate, glutathione and activity levels of antioxidative enzymes. Arsenic uptake in the seedlings declined by 72.5% in roots and 72.8% in shoots, when A. indica extract was present in the As treatment medium whereas with O. sanctum extract, the uptake declined by 67.2% in roots and 70.01% in shoots. Results suggest that both A. indica and O. sanctum aqueous extracts have potentials to alleviate arsenic toxicity in rice plants and that A. indica can serve as better As toxicity alleviator compared to O. sanctum. 相似文献
Using agro-morphological characters and microsatellite markers, advance breeding lines of rice were discriminated for their ability to tolerate drought stress at reproductive stage. Experimental materials consisting of 17 advance breeding lines and a check were evaluated in randomized block design with three replications under irrigated condition and drought condition created under rainout shelter during three consecutive years. An analysis of variance revealed significant differences among the genotypes for all the ten agro-morphological characters evaluated under both the conditions across the years. Principal component analysis showed the relative importance of root length, number of tillers per plant, number of grains per panicle, harvest index and grain yield per plant among agro-morphological characters and stress tolerance level, stress susceptibility index, stress tolerance index and drought tolerance efficiency among drought tolerance indices as the important classification variables. Relative mean performance in respect of grain yield as well as drought tolerance indices reflected remarkably greater degree of drought tolerance in 11 advance breeding lines and the check, discriminating them from remaining entries under evaluation. Utilizing a panel of 32 microsatellite primers, selective amplification of targeted genomic regions revealed that the primers RM 72, RM 163, RM 212, RM 225, RM 231, RM 302, RM 327, RM 518, RM 521, RM 555, RM 1349, RM 3549 and RM 5443 were highly informative with greater gene diversity and discrimination ability. Hierarchical cluster analysis based on molecular profiles discriminated the entries into five genotypic groups and drought tolerant entries were accommodated into three distinct groups with remarkably greater efficiency (85.7%). Principal coordinate analysis based two dimensional plots of microsatellites dependent genetic profiles displayed a very close correspondence with the genotypic clustering pattern revealed from a perusal of dendrogram. Sequential exclusion of primers in cluster analysis led to identification of RM 212, RM 231, RM 324, RM 431, RM 521, RM 3549 and RM 6374 as the most useful primers for discrimination of drought tolerant and susceptible lines of rice. Molecular profiling based on these markers can be utilized as efficient tools for discrimination and identification of drought tolerant lines.
Many cellulose degrading and modifying enzymes have distinct parts called carbohydrate binding modules (CBMs). The CBMs have been shown to increase the concentration of enzymes on the insoluble substrate and thereby enhance catalytic activity. It has been suggested that CBMs also have a role in disrupting or dispersing the insoluble cellulose substrate, but dispute remains and explicit evidence of such a mechanism is lacking. We produced the isolated CBMs from two major cellulases (Cel6A and Cel7A) from Trichoderma reesei as recombinant proteins in Escherichia coli. We then studied the viscoelastic properties of native unmodified cellulose nanofibrils (CNF) in combination with the highly purified CBMs to detect possible functional effects of the CBMs on the CNF. The two CBMs showed clearly different effects on the viscoelastic properties of CNF. The difference in effects is noteworthy, yet it was not possible to conclude for example disruptive effects. We discuss here the alternative explanations for viscoelastic effects on CNF caused by CBMs, including the effect of ionic cosolutes. 相似文献
The genus Lactobacillus has been widely used in food industry as starter or adjunct culture due to its probiotic features. Its biotechnological features improve the spectrum of uses of lactobacilli, which can affect its applicability directly. In this sense, this literature review gathers information and discusses the biotechnological potential of technological/probiotic lactobacilli aiming to improve food quality and human health. The primary and secondary metabolism generates specific substances, such as organic acids, carbon dioxide, hydrogen peroxide, diacetyl, fatty acids, and bacteriocins, which are determinant due to their probiotic potential, antimicrobial activity, and the development of new food flavors. In order to become industrially and commercially attractive, it is necessary develop a large-scale process with lower production costs. 相似文献