Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fine-structural changes are induced in Tetrahymena by exposure to 7.5% dimethyl sulfoxide (DMSO) in the presence of growth medium. Some of these changes (nucleolar, mitochondrial, peroxisomal) resemble those seen during starvation, in agreement with the previously reported inhibitory effect of DMSO on food-vacuole formation; however, changes such as helical formations of polyribosomes indicate additional internal actions of the reagent. The effects vary to some extent within the same group of cells, suggesting that sensitivity to the reagent may differ with the stage in the cell cycle. The structural changes induced by a 1-hr exposure to DMSO are reversible, but recovery of the cells after removal of the reagent is slower than that seen after starvation. The observations suggest that the recovery is associated with renewed synthesis.
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PMID:Effects of dimethyl sulfoxide on Tetrahymena pyriformis GL. Fine structural changes and their reversibility. 40 54

beta-D-Xylosides have been used to perturb proteoglycan (PG) synthesis to elucidate the function of PGs in a number of cellular processes, including proliferation, migration, and differentiation. This study was designed to examine whether specific xylosides affect the proliferation of several different cell types and, if so, whether this effect is dependent on altered PG synthesis via the false acceptor pathway. Both methylumbelliferyl beta-D-xylopyranoside and p-nitrophenyl beta-D-xylopyranoside (PNP beta-xyloside) inhibit cell proliferation and modulate PG synthesis; however, the alpha form of PNP xyloside which does not perturb PG synthesis inhibits the proliferation of cultured cells on a molar basis equally as well as the beta form. Conversely, beta-methyl xylopyranoside stimulates the synthesis of free glycosaminoglycan chains equally as well as PNP beta-xyloside and yet has no measurable effect on cell proliferation at comparable doses, indicating that cells can grow normally while experiencing disruption of their proteoglycan metabolism. At doses ranging from 0.5 to 5 mM, PNP beta-xyloside arrests cells in the G1 phase of the cell cycle at the same time point as serum starvation. It also delays the exist of cycling cells from the S phase. This treatment is not cytotoxic and is rapidly reversed by the replacement of PNP beta-xyloside containing medium with control medium. Dimethyl sulfoxide, the most commonly used solvent for beta-xyloside in proteoglycan studies, potentiates the inhibitory effect of PNP beta-xyloside on cell proliferation. These results indicate that the perturbation of PG synthesis via the false acceptor pathway can be uncoupled from control of cell proliferation.
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PMID:Altered proteoglycan synthesis via the false acceptor pathway can be dissociated from beta-D-xyloside inhibition of proliferation. 163 72

Culture of Hep G2 cells in medium containing 2% (v/v) dimethyl sulphoxide (DMSO) resulted in a slowing of growth and a marked change in morphological appearance. By day 6, cultures containing DMSO had one-third the number of cells compared with parallel control cultures. Measurement of 125I-epidermal-growth-factor (EGF) binding to DMSO-treated cells revealed a striking time-dependent elevation in specific EGF binding to their cell surface. Increased binding was detectable within 24 h of the start of DMSO treatment, reaching, by 6 days, levels almost 25 times greater than those for control cells. Addition of EGF to DMSO-treated cells caused a rapid down-regulation of the EGF receptor, but did not alter their proliferation rate. Slowing of growth by other means, such as serum starvation, growth to confluence or culture in the presence of sodium butyrate, did not affect 125I-EGF binding, indicating a specific effect of DMSO on these cells.
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PMID:Dimethyl sulphoxide induces a reduced growth rate, altered cell morphology and increased epidermal-growth-factor binding in Hep G2 cells. 165 2

A novel rice genomic sequence encoding coding segments homologous to other metallothionein-like genes was isolated from Oryza sativa genomic library. This sequence, hereby designated as rgMT (rice genomic metallothionein-like gene), consists of two exons and one intron. From the coding sequence, it is predicted that rgMT encodes one protein of 74 amino acids. Differential expression of rgMT in rice plants was observed as mature transcripts were more abundant in roots than in leaves and sheaths. Under different stress conditions, such as excess heavy metals and heat shock, expression of rgMT was significantly elevated. This was especially noticeable with 250 microM CuCl2 for 16 h, 40 degrees C heat for 2 h and 0.06% DMSO for 1 h. Under sucrose starvation, rgMT transcripts also increased with time up to 72 h. During recovery from sucrose starvation, the transcripts declined slightly within 12 h of recovery. rgMT transcripts were also seen to have increased expression in senescent leaves. These results support the notion that rgMT is a stress-inducible gene in rice heretofore unreported.
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PMID:A novel stress-inducible metallothionein-like gene from rice. 763 10

Myxococcus xanthus is a gram-negative gliding bacterium that exhibits a complex life cycle. Exposure of M. xanthus to chemicals like dimethyl sulfoxide (DMSO) at nondeleterious concentrations or the depletion of nutrients caused several negative responses by the cells. DMSO (> 0.1 M) or nutrient depletion triggered a repellent response: cell swarming was inhibited and FrzCD (a methyl-accepting chemotaxis protein) was demethylated; higher concentrations of DMSO (> 0.3 M) or prolonged starvation induced an additional response which involved cellular morphogenesis: DMSO caused cells to convert from rod-shaped vegetative cells to spherical, environmentally resistant "DMSO spores," and starvation induced myxospore formation in the fruiting bodies. In order to investigate the nature of these responses, we isolated a number of mutants defective in negative chemotaxis and/or sporulation. Characterization of these mutants indicated that negative chemotaxis plays an important role in colony swarming and in developmental aggregation. In addition, the results revealed some of the major interrelationships between the signal transduction pathways which respond to negative stimuli: (i) DMSO exposure and starvation were initially sensed by different systems, the neg system for DMSO and the stv system for starvation; (ii) the repellent response signals triggered by DMSO or starvation were then relayed by the frz signal transduction system; mutants defective in these responses showed altered FrzCD methylation patterns; and (iii) the morphogenesis signals in response to DMSO or starvation utilize a group of genes involved in sporulation (spo).
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PMID:Isolation and phenotypic characterization of Myxococcus xanthus mutants which are defective in sensing negative stimuli. 830 May 25

Myxococcus xanthus is a Gram-negative bacterium that glides on a solid surface and displays a wide range of social behaviour including microbial development. The frz genes are homologues to the chemotaxis genes of Escherichia coli and Salmonella typhimurium and have been shown to be involved in microbial development. However, chemotaxis has never been clearly demonstrated in Myxococcus. In this study, we showed that M. xanthus exhibited tactic movements to many chemicals when they were subjected to steep and stable chemical gradients. M. xanthus was observed to spread into areas with abundant nutrients like yeast extract or Casitone and avoid areas with no nutrients or repellents (short-chain alcohols or DMSO). Responses to attractants and repellents were additive. Movement towards attractants or away from repellents required the frz genes and was correlated with methylation or demethylation of FrzCD, a methyl-accepting taxis protein. Furthermore, the frz genes were found to be required for both fruiting body formation during starvation and swarming in nutrient-rich medium. In wild-type strains, cells near the colony edge were observed to swarm towards the surrounding growth medium and to contain highly methylated FrzCD; cells near the colony centre contained mainly demethylated FrzCD and showed directed movement towards the colony edge. FrzCD was also found to be methylated during the aggregation stage of fruiting body formation on agar but largely demethylated in cells shaken in liquid starvation media. An frzE mutant failed to exhibit directed cell movements and no longer showed modification of FrzCD under these conditions. These observations suggest that M. xanthus does show chemotactic movements, that these movements require the frz genes, and that chemotaxis plays a very important role in the social behaviour of this organism.
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PMID:Chemotaxis plays a role in the social behaviour of Myxococcus xanthus. 841 6

Differentiation of NG108-15 neuroblastoma cells following exposure to either 1.5% dimethyl sulfoxide (DMSO)/0.5% fetal bovine serum (FBS) or serum starvation resulted in significant differences in angiotensin (AT) receptor levels and the AT1/AT2 receptor ratio. When NG108 cells were differentiated for 4 days with DMSO/low serum, the number of AT binding sites increased 30-fold compared with the binding levels on undifferentiated (blast) cells. However, cells differentiated by serum starvation for 4 or 14 days resulted in only a modest 2.5- and fivefold increase in AT receptor levels, respectively, over the levels seen with the undifferentiated cells. KD values for all treatment conditions were not significantly different (0.71 +/- 0.11 nM, p = 0.06). Using the AT1 and AT2 isoform-specific receptor antagonists losartan and PD123319, the relative numbers of AT receptor subtypes on undifferentiated and differentiated cells were determined by competitive inhibition against 125I-[Sar1,Ile8]-angiotensin II (sarile). A majority of the AT receptors on undifferentiated NG108 cells were the AT1 subtype (AT1/AT2 receptor ratio of 8:3). Differentiation by serum starvation and DMSO/low serum treatment resulted in fivefold and 30-fold increases in AT receptor levels, respectively, compared with the levels seen with the undifferentiated cells. Although serum starvation increased the total number of AT1 and AT2 receptors, it did not significantly alter the AT1/AT2 receptor ratio. In contrast, differentiation with DMSO/low serum both increased the total number of AT1 and AT2 receptors and reversed the AT1/AT2 receptor ratio (1:3). The increase in AT receptors following differentiation with DMSO/low serum for 4 days was largely accounted for by an 80-fold increase in the AT2 receptor level. Previous studies by Tallant at al. (1991) and Bryson et al. (1992) reported increased AT2 receptor expression following neuroblastoma differentiation with dibutyryl cyclic AMP and DMSO/low serum, respectively, and suggested a role for the AT2 receptor in neuronal differentiation. In the present study, we have extended these earlier observations by demonstrating that the method of differentiation significantly affects both the AT receptor level and the ratio of AT1 to AT2 receptor expression. Finally, our findings indicate that the AT2 receptor is expressed as a consequence of neuronal maturation and dose not mediate morphological differentiation.
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PMID:Differentiation of NG108-15 neuroblastoma cells by serum starvation or dimethyl sulfoxide results in marked differences in angiotensin II receptor subtype expression. 876 61

We found that when human promyelocytic leukemic cells (HL-60 cells) were induced to differentiate along the granulocytic lineage by two diverse mechanisms (starvation for an essential amino acid or treatment with DMSO), there was a marked decrease in the intracellular guanosine 5'-triphosphate (GTP) concentration with no change in the guanosine 5'-diphosphate (GDP) concentration. Differentiation was prevented by guanine or guanosine in a dose-dependent manner. We showed that: (a) guanine had to be converted to a nucleotide because it did not prevent differentiation of hypoxanthine-guanine phosphoribosyltransferase-deficient HL-60 cells; (b) the effect of guanine correlated with a return of the cytosolic GTP:GDP ratio to normal; and (c) other purine bases were not effective. We hypothesized that the decreased GTP:GDP ratio in differentiating HL-60 cells might decrease the relative amount of GTP bound to Ras, a key regulatory GTP-binding protein important to cell growth and differentiation. Consistent with data showing that HL-60 cells harbor an activating N-Ras mutation, we found that the percentage of Ras molecules in the GTP-bound state was high in proliferating HL-60 cells (27 +/- 3%) compared with other cultured mammalian cells (< 1%); however, we found no change in the activation state of Ras when cells ceased to proliferate and differentiated in response to DMSO, amino acid deprivation, or inhibitors of guanylate synthesis. We conclude that: (a) a decrease in the intracellular GTP concentration is necessary for HL-60 cells to undergo granulocytic differentiation; and (b) although a high degree of Ras activation contributes to the malignant phenotype of the cell, there is no change in the activation state of Ras during granulocytic differentiation.
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PMID:A decrease in the intracellular guanosine 5'-triphosphate concentration is necessary for granulocytic differentiation of HL-60 cells, but growth cessation and differentiation are not associated with a change in the activation state of Ras, the transforming principle of HL-60 cells. 899 34

Myxococcus xanthus is a Gram-negative, soil-dwelling bacterium with a complex life cycle which includes fruiting body formation and sporulation in response to starvation. This developmental process is slow, requiring a minimum of 24-48 h, and requires cells to be at high cell density on a solid surface. It is known that, in the absence of starvation, vegetatively growing cell suspensions can form 'glycerol spores' when exposed to high levels of glycerol, usually 0.5 M. The cells differentiate from rods to resistant spheres rapidly (2-4 h) and synchronously. We have found that the chromosomally encoded beta-lactamase of M. xanthus can be induced by numerous beta-lactam antibiotics as well as by non-specific inducers including glycine and many D-amino acids. In addition, D-cycloserine, phosphomycin, and hen egg-white lysozyme also induce beta-lactamase in this bacterium. Unexpectedly, agents which induce beta-lactamase can induce 'glycerol spores'; all of the agents tested which induce glycerol spores (glycerol, DMSO, ethylene glycol) also induce beta-lactamase. During the induction of sporulation, beta-lactamase activity increases, reaching a peak during the morphological transition from rod-shaped cells to spherical spores. These spores are viable and resistant to many treatments which disrupt vegetatively growing rods but are not as resistant as fruiting body spores. The concomitant induction of beta-lactamase and starvation-independent sporulation suggests that these processes share a common signal-transduction pathway. These results also suggest that starvation-independent sporulation may be an adaptation of cells in order to resist agents that damage peptidoglycan structure and therefore threaten cell survival.
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PMID:Starvation-independent sporulation in Myxococcus xanthus involves the pathway for beta-lactamase induction and provides a mechanism for competitive cell survival. 919 10

The uptake of the aminoacid biosynthesis inhibitor, used as the broad-spectrum herbicide ingredient, glyphosate (N-[phosphonomethyl]-glycine) was investigated in E. coli as a model to study mechanisms of cell resistance to antimetabolites as drugs and pesticides. Unlike the glyphosate-degrading Arthrobacter sp. strain for which the first successful measurement of glyphosate uptake and its inhibition by orthophosphate was reported, E. coli K-12 cannot take up this inhibitor either in the presence of orthophosphate, or after a prolonged starvation for it. However, cells made "competent" after an overnight cold CaCl2 exposure followed by dimethyl sulfoxide (DMSO) treatment could take up this compound (Km for glyphosate uptake, 274 microM). Neither amino acids, belonging to a single transport system, nor orthophosphate gave essential inhibition of glyphosate uptake by these cells.
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PMID:Uptake of the herbicidal glyphosate by Escherichia coli K-12. 1037 6


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