Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
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The complex problems of microbiological degradation of synthetic plastics and a fairly wide variety of 62 testing materials, belonging to 14 major groups of plastics, are described. Adaequate and reliable testing techniques had to be devised. Drawing on the experiences of H. Braun, 1930, and of Bushnell and Haas, 1941, as to the metabolism of bacteria and the utilization of certain hydrocarbons by microorganisms, and previous research work by A. Schwartz in Berlin, 1959-60, on microbial corrosion of plastics, methods of laboratory testing were developed. The bacteriological technique was based on selection of aerobic microorganisms, which were, by starvation, adapted to use the plastic materials as their only carbon source; foreign carbon sources had to be strictly eliminated; emphasis was laid on proper, double control cultures. The test organisms involved included P. aeruginosa and fluorescens strains, also a certain species of Candida, and mixtures of soil, sewage and garbage organisms grown on exposed plastic surfaces. By means of series of passages the selective adaptation and conservation of these organisms was continued up to 4 1/2 years. An anaerobic adaptation method for Desulfovibrio desulfuricans was developed and used successfully. After preliminary experimentation (Soil burial, sewage and garbage exposure tests) in the laboratory as well as in the open, a large scale Field testing programme under realistic and to some extent extreme conditions was implemented: Nine different plastic materials comprising eight plain high polymer plastics and for comparison one synthetic Cellulose derivate, together with glass control samples, were exposed in twelve different sewage, garbage, and soil media over a period of 3 months to 2 years, and subsequently examined. On the basis of the bacteriological results obtained from the adaptation series the test materials were classified into three categories, corresponding to the stimulation of bacterial growth: Group one, which allowed strong proliferation, included certain types of plasticized P.V.C. and Cellulose esters, as expected, and, as a new result, Polyurethane rubber; the latter showed clear signs of surface corrosion. Group two, which induced a clear but moderate growth, comprised a nylon trade type of Polyamide. Gruop three, allowing weak but still recognisable growth, included Formaldehyde pressure resing (Bakelite). This was surprising as it was thought that the formaldehyde and phenol components would exert a bacteriocidic or at least bacteriostatic effect. The results of the long and time consuming adaptation series with Pseudomonas aeruginosa were confirmed by the manometric dissimilation method of O. Warburg by means of the Braun/Melsungen apparatus. With this subtle but elegant procedure results and graphical recordings were obtained within hours and days...
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PMID:[Mutual relations between plastic materials and bacteria (author's transl)]. 82 69

The widespread distribution of enzymes classed as semicarbazide-sensitive amine oxidases (SSAO enzymes) throughout a very wide range of eukaryotic as well as prokaryotic organisms encourages the aspirations of those who wish to demonstrate physiological, pathological or pharmacological importance. Such enzymes are found in several tissues of mammals, both freely soluble, as in blood plasma, and membrane-bound, for example, in smooth muscle and adipose tissue. While they are capable of deaminating many amines with the production of an aldehyde and hydrogen peroxide, doubt still surrounds the identity of the most important endogenous substrates for these enzymes. At present, methylamine and aminoacetone appear to head the list of candidates. The possibility that SSAO enzymes can convert amine substrates to highly toxic metabolites is illustrated by the production of acrolein from the xenobiotic amine, allylamine and formaldehyde and methylglyoxal from methylamine and aminoacetone, respectively. Activities of SSAO enzymes may be influenced by physiological changes, such as pregnancy or pathologically by disease states, including diabetes, tumours and burns. Increased deamination of aminoacetone by tissue and plasma SSAO enzymes as a result of its increased production from L-threonine in conditions such as exhaustion, starvation and diabetes mellitus may be harmful. Such dangers could be mitigated either physiologically by a compensatory reduction in SSAO activity or pharmacologically by treatment with inhibitors of SSAO.
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PMID:Some aspects of the pathophysiology of semicarbazide-sensitive amine oxidase enzymes. 858 67

N-Nitrosodimethylamine (NDMA), a common food contaminant, is a potent liver carcinogen in rodents. A high presystemic intestinal metabolism has been shown for several nitrosamines including environmentally important compounds. We determined the metabolism of 1 micron [14C]-NDMA in isolated perfused mouse intestinal segments. We found NDMA to be equally distributed between the absorbed fluid and the perfusate. During a 2-h perfusion period, 0.13% of the radioactivity was converted to CO2. The formation of CO2 was decreased by pretreatment with diallylsulfide or addition of SKF 525A, and slightly increased by phenobarbital. Hydrophilic metabolites were found in the absorbate (0.9%) and perfusate (3.8%) of untreated mice. The amount of metabolites in the absorbate was increased by treatment with acetone or phenobarbital (8-fold), but not after starvation, with formaldehyde being present only in phenobarbital-treated animals. Treatment with diallylsulfide or addition of SKF 525A reduced the amount of metabolites in acetone-treated animals to control values. In conclusion, intestinal turnover does not significantly reduce the body burden of orally ingested NDMA and thus is not a first-line defense against this carcinogenic nitrosamine. NDMA metabolism has been attributed to the presence of cytochrome P450IIE1, which has not been detected in the intestine of untreated animals. The low turnover of NDMA, the induction by acetone and phenobarbital treatment, and the inhibition by diallylsulfide suggest the presence of low amounts of this or related cytochrome P450 isozyme(s) in mouse intestine.
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PMID:Presystemic intestinal metabolism of N-nitrosodimethylamine in mouse intestine. 1010 91

Ketosis occurs in ketoacidosis or malnourishment. When either is suspected in relation to a death, it may be important to analyze for ketosis at autopsy. We encountered a case where starvation was suspected in a deceased nursing home resident, where the body had been embalmed prior to autopsy. Gas chromatography (GC) was unable to separate acetone from formaldehyde, a component of embalming fluid. The Acetest is a simple test that can detect acetone and acetoacetate in body fluids. We validated the Acetest with GC on vitreous. The Acetest and GC were consistent except at very low levels of acetone or acetoacetate. The sensitivity of the Acetest for acetoacetate in vitreous was 10 mg/dL, consistent with early starvation. Significant interference from embalming fluid did not occur. The Acetest was negative in the described case. The Acetest is a simple and useful test for the detection of ketosis in embalmed autopsies.
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PMID:Detection of ketosis in vitreous at autopsy after embalming. 1206 59

Although starvation is considered one of the most important induces of ciliate encystment, its nature has been unclear. Euplotes is a well-known ciliate genus, but the relationship in Euplotes between encystment and food has not been reported. The encystment of Euplotes elegans is facilitated when it is transferred to Chalkley's solution without bacteria as food. A higher ciliate density also facilitates encystment. Thus, starvation and ciliate density needed to be examined. Ciliates were inoculated into 3 treatments: Chalkley's solution with formaldehyde-fixed bacteria as nutritive particles (FFB group), with polystyrene latex particles as non-nutritive particles (PLP group), and without particles (control group). Cysts appeared fastest and ciliate numbers increased in the FFB group. Although the encystment kinetics of the PLP group was similar to that of the control group, the encystment rate of the PLP group was lower than that of the control group in the earliest phase. This suggests that the ciliates were temporarily deceived into feeding on PLP, because they had food vacuoles containing PLP during the earliest phase of incubation. A cell-free old culture solution from a stationary phase, which probably contained excreted substances from high-density ciliates, also facilitated encystment.
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PMID:Encystment-inducing factors in the ciliate Euplotes elegans. 1214 74

Glutathione (GSH: L-gamma-glutamyl-L-cysteinylglycine) is present in high concentrations up to 10 mM in yeast cells. Its very low redox potential (E'(o)=-240 mV for thiol disulfide exchange) gives this tripeptide the properties of a cellular redox buffer. In Saccharomyces cerevisiae and non-conventional yeasts (NCY), GSH may be involved in basic cellular functions such as the maintenance of mitochondrial and membrane integrity. GSH also assumes pivotal roles in (i) response to sulfur and nitrogen starvation; (ii) detoxification of endogenous toxic metabolites, such as excess formaldehyde produced during the growth of the methylotrophic yeasts Hansenula polymorpha, Candida boidinii and Kloeckera sp.; (iii) protection against oxidative stress provoked by exposure of the cells to reactive oxygen species including peroxides and hydroperoxides; (iv) detoxification of xenobiotics such as halogenated aromatics, alkylating agents and arsenite; (v) resistance to heavy-metal stress exemplified by the responses of S. cerevisiae and Schizosaccharomyces pombe to cadmium salts; (vi) yeast<-->mycelium transition in Candida and Aureobasidium sp.
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PMID:An overview on glutathione in Saccharomyces versus non-conventional yeasts. 1270 79

Glutathione (GSH; gamma-L-glutamyl-L-cysteinyl-glycine), a non-protein thiol with a very low redox potential (E'0 = 240 mV for thiol-disulfide exchange), is present in high concentration up to 10 mM in yeasts and filamentous fungi. GSH is concerned with basic cellular functions as well as the maintenance of mitochondrial structure, membrane integrity, and in cell differentiation and development. GSH plays key roles in the response to several stress situations in fungi. For example, GSH is an important antioxidant molecule, which reacts non-enzymatically with a series of reactive oxygen species. In addition, the response to oxidative stress also involves GSH biosynthesis enzymes, NADPH-dependent GSH-regenerating reductase, glutathione S-transferase along with peroxide-eliminating glutathione peroxidase and glutaredoxins. Some components of the GSH-dependent antioxidative defence system confer resistance against heat shock and osmotic stress. Formation of protein-SSG mixed disulfides results in protection against desiccation-induced oxidative injuries in lichens. Intracellular GSH and GSH-derived phytochelatins hinder the progression of heavy metal-initiated cell injuries by chelating and sequestering the metal ions themselves and/or by eliminating reactive oxygen species. In fungi, GSH is mobilized to ensure cellular maintenance under sulfur or nitrogen starvation. Moreover, adaptation to carbon deprivation stress results in an increased tolerance to oxidative stress, which involves the induction of GSH-dependent elements of the antioxidant defence system. GSH-dependent detoxification processes concern the elimination of toxic endogenous metabolites, such as excess formaldehyde produced during the growth of the methylotrophic yeasts, by formaldehyde dehydrogenase and methylglyoxal, a by-product of glycolysis, by the glyoxalase pathway. Detoxification of xenobiotics, such as halogenated aromatic and alkylating agents, relies on glutathione S-transferases. In yeast, these enzymes may participate in the elimination of toxic intermediates that accumulate in stationary phase and/or act in a similar fashion as heat shock proteins. GSH S-conjugates may also form in a glutathione S-transferases-independent way, e.g. through chemical reaction between GSH and the antifugal agent Thiram. GSH-dependent detoxification of penicillin side-chain precursors was shown in Penicillium sp. GSH controls aging and autolysis in several fungal species, and possesses an anti-apoptotic feature.
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PMID:Glutathione, altruistic metabolite in fungi. 1551 28

The cell fixatives formaldehyde and KMnO4 at low concentrations reversibly inhibit the movement of D. discoideum amoebae without directly interfering with cell viability. This inhibition of cell movement is accompanied by the decreased attachment of cells to substratum. When the tenacity and attachment of immobilized cells are artificially increased by compressing cells between two glass surfaces, the amoebae begin to move even in the presence of the fixatives. Amoebae starved for 24 hours, subjected to fixatives and a mineral salt solution in which they remained motionless, maintained chemotactic responses to folic acid and only after a few hours of active locomotion became reactive to cAMP, in contrast to amoebae that reacted to cAMP after starvation in the absence of fixatives.
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PMID:Reversible inhibition of movement in the amoebae Dictyostelium discoideum and its effect on chemoattractant recognition. 1905 36

Hormone receptors, hormones and signal transduction pathways characteristic of higher vertebrates can be observed also in the unicellular Tetrahymena. Previous work showed that stress conditions (starvation, high temperature, high salt concentration, formaldehyde or alcohol treatment) elevated the intracellular level of four hormones (ACTH, endorphin, serotonin and T(3)). Here, the effect of other stressors (CuSO4 poisoning, tryptophan hydroxylase inhibitor parachlorophenylalanine (PCPA) treatment) on the same and other hormones (epinephrine, insulin, histamine) was studied, using immunocytochemistry and flow cytometric analysis. It was found, that each effect increased the intracellular hormone contents, but some hormones (histamine, T(3)) were less reactive. Insulin--which is a life-saving factor for Tetrahymena--itself provoked elevation of hormone amounts in association with a stressor, further increased the level of hormones. It was concluded that the ancestor of Selye's General Adaptation Syndrome (GAS) can be found already at unicellular level, and this possibly has a life saving function.
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PMID:How applicable is the general adaptation syndrome to the unicellular Tetrahymena? 1910 78

How transcription factors affect chromatin structure to regulate gene expression in response to changes in environmental conditions is poorly understood in the green lineage. To shed light on this issue, we used chromatin immunoprecipitation and formaldehyde-assisted isolation of regulatory elements to investigate the chromatin structure at target genes of HSF1 and CRR1, key transcriptional regulators of the heat shock and copper starvation responses, respectively, in the unicellular green alga Chlamydomonas reinhardtii. Generally, we detected lower nucleosome occupancy, higher levels of histone H3/4 acetylation, and lower levels of histone H3 Lys 4 (H3K4) monomethylation at promoter regions of active genes compared with inactive promoters and transcribed and intergenic regions. Specifically, we find that activated HSF1 and CRR1 transcription factors mediate the acetylation of histones H3/4, nucleosome eviction, remodeling of the H3K4 mono- and dimethylation marks, and transcription initiation/elongation. By this, HSF1 and CRR1 quite individually remodel and activate target promoters that may be inactive and embedded into closed chromatin (HSP22F/CYC6) or weakly active and embedded into partially opened (CPX1) or completely opened chromatin (HSP70A/CRD1). We also observed HSF1-independent histone H3/4 deacetylation at the RBCS2 promoter after heat shock, suggesting interplay of specific and presumably more generally acting factors to adapt gene expression to the new requirements of a changing environment.
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PMID:Transcription factor-dependent chromatin remodeling at heat shock and copper-responsive promoters in Chlamydomonas reinhardtii. 2170 43


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