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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of sulfate and nitrogen concentrations of the rate and stoichiometry of microbial sulfate reduction were investigated for Desulfovibrio desulfuricans grown on lactate and sulfate in a chemostat at pH 7.0. Maximum specific growth rates (micro(max)), half-saturation coefficients (K(sul)), and cell yield (Y(c/Lac)) of 0.344 +/- 0.007 and 0.352 +/- 0.003 h (-1), 1.8 +/- 0.3 and 1.0 +/- 0.2 mg/L, and 0.020 +/- 0.003 and 0.017 +/- 0.003 g cell/g lactate, respectively, were obtained under sulfate-limiting conditions at 35 degrees C and 43 degrees C. Maintenance energy requirements for D. desulfuricans were significant under sulfate-limiting conditions. The extent of extracellular polymeric substance (EPS) produced was related to the carbon: nitrogen ratio in the medium. EPS production rate increased with decreased nitrogen loading rate. Nitrogen starvation also resulted in decreased cell size of D. desulfuricans. The limiting C : N ratio (w/w) for D. desulfuricans was in the range of 45 : 1 to 120 : 1. Effects of sulfide on microbial sulfate reduction, cell size, and biomass production were also investigated at pH 7.0. Fifty percent inhibition of lactate utilization occurred at a total sulfide concentration of approximately 500 mg/L. The cell size of D. desulfuricans decreased with increasing total sulfide concentration. Sulfide inhibition of D. desulfuricans was observed to be a reversible process.
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PMID:Factors affecting microbial sulfate reduction by Desulfovibrio desulfuricans in continuous culture: limiting nutrients and sulfide concentration. 1860 Nov 73

A horizontal biotrickling filter (HBTF) was used to inoculate autotrophic sulfide-oxidizing and ammonia-oxidizing microbial consortiums over H2S-exhausted carbon for co-treating H2S and NH3 waste gas in a long-term operation. In this study, several aspects (i.e., pH change, shock loading and starvation) of the dynamic behavior of the HBTF were investigated. The metabolic products of N and S bearing species in recycling liquid and biological activities of the biofilm were analyzed to explain the observed phenomena and further explore the fundamentals behind. In the pH range of 4-8.5, although the removal efficiencies of H2S and NH3 remained 96-98% and 100%, respectively, the metabolic products demonstrated different removal mechanisms and pathways. NH4-N and NO2/NO3-N were dominated at pH < or = 6 and > or = 7, respectively, indicating the differentiated contributions from physical/chemical adsorption and bio-oxidation. Moreover, the HBTF demonstrated a good dynamic stability to withstand shock loadings by recovering immediately to the original. During shock loading, only 15.4% and 17.9% of captured H2S and NH3 was biodegraded, respectively. After 2, 11, and 48 days of starvation, the HBTF system reached a full performance within reasonable re-startup times (2-80 h), possibly due to the consumption of reduced S and N species in biomass or activated carbon thus converted into SO4-S and NO3-N during starvation period. The results helped to understand the fundamental knowledge by revealing the effects of pH and transient loadings linked with individual removal mechanism for H2S and NH3 co-treatment in different conditions.
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PMID:Transient-state biodegradation behavior of a horizontal biotrickling filter in co-treating gaseous H2S and NH3. 1899 23

THE DEDUCTIONS THAT MAY BE DRAWN FROM THE RESULTS OF THESE EXPERIMENTS ARE AS FOLLOWS: That the normal vital resistance of rabbits to infection by streptococcus pyogenes (erysipelatos) is markedly diminished through the influence of alcohol when given daily to the stage of acute intoxication. That a similar, though by no means so conspicuous, diminution of resistance to infection and intoxication by the bacillus coli communis also occurs in rabbits subjected to the same influences. And that, while in alcoholized rabbits inoculated in various ways with staphylococcus pyogenes aureus, individual instances of lowered resistance are observed, still it is impossible to say from these experiments that in general a marked difference is noticed between alcoholized and non-alcoholized animals as regards infection by this particular organism. It is interesting to note that the results of inoculation of alcoholized rabbits with the erysipelas coccus correspond in a way with clinical observations on human beings addicted to the excessive use of alcohol when infected by this organism. In the course of the work an effort was made to determine if, through the oxidation of alcohol in the tissues to acids of the corresponding chemical group, the increase of susceptibility could be referred to a diminution in the alkalinity of the blood as a result of the presence of such acids. The number of experiments thus far made on this point is too small to justify dogmatic statements, but from what we have gathered there is but little evidence in support of this view. Throughout these experiments, with few exceptions, it will be seen that the alcoholized animals not only showed the effects of the inoculations earlier than did the non-alcoholized rabbits, but in the case of the streptococcus inoculations the lesions produced (formation of miliary abscesses) were much more pronounced than are those that usually follow inoculation with this organism. With regard to the predisposing influence of the alcohol, one is constrained to believe that it is in most cases the result of structural alterations consequent upon its direct action on the tissues, though in a number of the animals no such alteration could be made out by macroscopic examination. I am inclined, however, to the belief, in the light of the work of Berkley and of Friedenwald, done under the direction of Prof. Welch, in the Pathological Laboratory of the Johns Hopkina University, that a closer study of the tissues of these animals would have revealed in all of them structural changes of such a nature as to indicate disturbances of important vital functions of sufficient gravity to fully account for the loss of normal resistance. The conspicuous influence of the alcohol on the gastric mucous membrane in many of these animals, with the consequent disturbance of nutrition, is undoubtedly the explanation of the marked loss in body weight that was observed in many of the animals employed in these experiments. In this light the susceptibility induced by alcohol to excess is somewhat analogous to that induced by starvation, where we see the resistance of animals to particular forms of infection very markedly diminished.
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PMID:THE INFLUENCE OF ACUTE ALCOHOLISM ON THE NORMAL VITAL RESISTANCE OF RABBITS TO INFECTION. 1986 7

Sulfur plays a pivotal role in the cellular metabolism of many organisms. In plants, the uptake and assimilation of sulfate is strongly regulated at the transcriptional level. Regulatory factors are the demand of reduced sulfur in organic or non-organic form and the level of O-acetylserine (OAS), the carbon precursor for cysteine biosynthesis. In plants, cysteine is synthesized by action of the cysteine-synthase complex (CSC) containing serine acetyltransferase (SAT) and O-acetylserine-(thiol)-lyase (OASTL). Both enzymes are located in plastids, mitochondria and the cytosol. The function of the compartmentation of the CSC to regulate sulfate uptake and assimilation is still not clearly resolved. To address this question, we analyzed Arabidopsis thaliana mutants for the plastidic and cytosolic SAT isoenzymes under sulfur starvation conditions. In addition, subcellular metabolite analysis by non-aqueous fractionation revealed distinct changes in subcellular metabolite distribution upon short-term sulfur starvation. Metabolite and transcript analyses of SERAT1.1 and SERAT2.1 mutants [previously analyzed in Krueger et al. (Plant Cell Environ 32:349-367, 2009)] grown under sulfur starvation conditions indicate that both isoenzymes do not contribute directly to the transcriptional regulation of genes involved in sulfate uptake and assimilation. Here, we summarize the current knowledge about the regulation of cysteine biosynthesis and the contribution of the different compartments to this metabolic process. We relate hypotheses and views of the regulation of cysteine biosynthesis with our results of applying sulfur starvation to mutants impaired in compartment-specific cysteine biosynthetic enzymes.
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PMID:Impact of sulfur starvation on cysteine biosynthesis in T-DNA mutants deficient for compartment-specific serine-acetyltransferase. 2037 51

Sulfur is an essential component for the biosynthesis of the sulfur-containing amino acids L-methionine and L-cysteine. Under sulfur-starvation conditions, bacteria are capable of scavenging sulfur from sulfur-containing compounds and transporting it across membranes. Here, the crystal structure of the periplasmic aliphatic sulfonate-binding protein SsuA from Escherichia coli is reported at 1.75 A resolution in the substrate-free state. The overall structure of SsuA resembles the structures of other periplasmic binding proteins and contains two globular domains that form a cleft. Comparison with other periplasmic binding proteins revealed that one of the domains has been displaced by a rigid movement of 17 degrees . Interestingly, the tight crystal packing appears to be mediated by a 13-amino-acid tail from the cloning that folds within the cleft of the next monomer.
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PMID:Structure of the aliphatic sulfonate-binding protein SsuA from Escherichia coli. 2038 6

Sulfur element plays a pivotal role in plant growth and development. Recently, we have demonstrated that miR395 is crucial for the sulfate homeostasis through regulating the sulfate uptake, transport and assimilation in Arabidopsis thaliana. miR395 controls the sulfate concentration in the shoot by targeting three ATP sulfurylase genes (APS), which encode the first enzymes catalyzing sulfate activation in sulfur assimilation pathway. Furthermore, miR395 also regulates the transport of sulfate between leaves. Under sulfate starvation conditions, up-regulated miR395 represses the expression of SULTR2;1, which then confined the transport of sulfate from mature to young leaves. Of note, transcript expression analysis suggested that, unlike APS1 and APS4 mRNA, APS3 and shoot SULTR2;1 is in accordance with miR395 in response to sulfate deprivation. We proposed that the differential regulation of targets by miR395 may be required for adaptation to the sulfate deficiency environment. In addition, our results revealed that there is reciprocal regulation between SULTR2;1 and APS genes through miR395.
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PMID:Reciprocal regulation among miR395, APS and SULTR2;1 in Arabidopsis thaliana. 2093 95

APR2 is the dominant APR (adenosine 5'-phosphosulfate reductase) in the model plant Arabidopsis thaliana, and converts activated sulfate to sulfite, a key reaction in the sulfate reduction pathway. To determine whether APR2 has a role in selenium tolerance and metabolism, a mutant Arabidopsis line (apr2-1) was studied. apr2-1 plants had decreased selenate tolerance and photosynthetic efficiency. Sulfur metabolism was perturbed in apr2-1 plants grown on selenate, as observed by an increase in total sulfur and sulfate, and a 2-fold decrease in glutathione concentration. The altered sulfur metabolism in apr2-1 grown on selenate did not reflect typical sulfate starvation, as cysteine and methionine levels were increased. Knockout of APR2 also increased the accumulation of total selenium and selenate. However, the accumulation of selenite and selenium incorporation in protein was lower in apr2-1 mutants. Decreased incorporation of selenium in protein is typically associated with increased selenium tolerance in plants. However, because the apr2-1 mutant exhibited decreased tolerance to selenate, we propose that selenium toxicity can also be caused by selenate's disruption of glutathione biosynthesis leading to enhanced levels of damaging ROS (reactive oxygen species).
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PMID:Adenosine 5'-phosphosulfate reductase (APR2) mutation in Arabidopsis implicates glutathione deficiency in selenate toxicity. 2158 36

The molecular mode(s)-of-action of the toxic metal chromium has yet to be fully resolved. This Mini review focuses on interactions between chromate and sulfur in biological systems. Cr binds sulfur ligands, with cysteine and glutathione having the capacity to aggravate or ameliorate Cr toxicity. Competition between chromate and sulfate for uptake and in metabolism provokes sulfur starvation, which can be growth limiting. Recent data indicate that sulfur deficiency determines protein damage-related Cr toxicity, due to mRNA mistranslation caused by Cr-induced S limitation. Sulfur deprivation could contribute to additional aspects of Cr toxicity, including oxidative DNA damage and Cr related disease.
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PMID:Chromate toxicity and the role of sulfur. 2180 74

Sulfate and selenate uptake were investigated in both selenium (Se) hyperaccumulators (Astragalus racemosus and Astragalus bisulcatus) and closely related nonaccumulator species (Astragalus glycyphyllos and Astragalus drummondii). Sulfur (S) starvation increased Se accumulation, whereas increased selenate supply increased sulfate accumulation in both root and shoot tissues. cDNAs for homologs of groups 1 to 4 sulfate transporters were cloned from these Astragalus species to investigate patterns of expression and interactions with sulfate and selenate uptake. In contrast to all other previously analyzed plant species, abundant gene expression of putative sulfate transporters was observed for both Se-hyperaccumulating and nonaccumulating Astragalus, regardless of S and Se status. Furthermore, quantitative analysis of expression indicated a transcript level in Se-hyperaccumulating Astragalus comparable with other plant species under S deprivation. The high expression of sulfate transporters in certain Astragalus species may lead to enhanced Se uptake and translocation ability and therefore may contribute to the Se hyperaccumulation trait; however, it is not sufficient to explain S/Se discriminatory mechanisms.
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PMID:A comparison of sulfate and selenium accumulation in relation to the expression of sulfate transporter genes in Astragalus species. 2197 67

By installing a treatment of sulfur starvation, this paper studied the dynamic changes of rice seedling growth, cadmium (Cd) and non-protein thiol (NPT) contents, and glutathione S-transferase (GST) activity under Cd stress. Cd stress inhibited the seedling growth obviously, induced the synthesis of sulfhydryl (-SH) compounds, including non-protein thiol, glutathione, and phytochelatins, and made the GST activity decreased after an initial increase. Sulfur starvation somewhat increased the Cd uptake and translocation, but less affected the impacts of Cd stress. The contents of -SH compounds decreased, and the GST activity in root increased. It was suggested that the roles of -SH compounds and GST in Cd-resistance of rice were complementary, being able to alleviate the Cd toxicity to some extent.
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PMID:[Effects of sulfur starvation on the non-protein thiol content and glutathione S-transferase activity of rice seedlings under cadmium stress]. 2200 57


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