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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hormones may produce long-term effects on excitability by regulating K+ channel gene expression. Previous studies demonstrated that administration of dexamethasone, a glucocorticoid receptor agonist, to adrenalectomized rats, rapidly induces Kv1.5 K+ channel expression in the ventricle of the hear. Here, RNase protection assays and Northern blots are used to examine the cell type specificity of dexamethasone action and to test whether Kv1.5 gene expression can be regulated by a physiological stimulus. We show that Kv1.5 mRNA expression in the central nervous system is highest in the hypothalamus. However, dexamethasone treatment of adrenalectomized rats fails to affect Kv1.5 mRNA levels in hypothalamus or lung. In contrast, dramatic upregulation of Kv1.5 mRNA is seen in skeletal muscle and pituitary. Increased Kv1.5 message also found in isolated ventricular cardiomyocytes following in vivo treatment with dexamethasone. Finally, it is shown that cold stress of intact rats significantly increases cardiac Kv1.5 mRNA expression. We conclude that dexamethasone induction of Kv1.5 gene is tissue-specific. Furthermore, our results suggest that stress may act via glucocorticoids to increase Kv1.5 gene expression in ventricular cardiomyocytes. Hence, K+ channel gene expression can be influenced by physiological and pharmacological stimuli.
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PMID:Dexamethasone and stress upregulate Kv1.5 K+ channel gene expression in rat ventricular myocytes. 893 30

CspA, the major cold-shock protein of Escherichia coli, is dramatically induced during the cold-shock response. The amino acid sequence of CspA shows 43% identity to the "cold-shock domain" of the eukaryotic Y-box protein family, which interacts with RNA and DNA to regulate their functions. Here, we demonstrate that CspA binds to RNA as a chaperone. First, CspA cooperatively binds to heat-denatured single-stranded RNA if it is larger than 74 bases, causing a supershift in gel electrophoresis. A minimal concentration of CspA at 2.7 x 10(-5) M is absolutely required for this cooperative binding, which is sufficiently lower than the estimated cellular concentration of CspA (10(-4) M) in cold-shocked cells. No specific RNA sequences for CspA binding were identified, indicating that it has a broad sequence specificity for its binding. When the 142-base 5'-untranslated region of the cspA mRNA was used as a substrate for ribonucleases A and T1, the addition of CspA significantly stimulated RNA hydrolysis by preventing the formation of RNase-resistant bands due to stable secondary structures in the 5'-untranslated region. These results indicate that binding of CspA to RNA destabilizes RNA secondary structures to make them susceptible to ribonucleases. We propose that CspA functions as an RNA chaperone to prevent the formation of secondary structures in RNA molecules at low temperature. Such a function may be crucial for efficient translation of mRNAs at low temperatures and may also have an effect on transcription.
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PMID:CspA, the major cold-shock protein of Escherichia coli, is an RNA chaperone. 899 47

Low-temperature-induced nonculturable cells of the human pathogenic bacterium Vibrio vulnificus retained significant amounts of nucleic acids for more than 5 months. Upon permeabilization of fixed cells, however, an increasing number of cold-incubated cells released the nucleic acids. This indicates substantial degradation of DNA and RNA in nonculturable cells prior to fixation. Treatment of permeabilized cells with DNase and RNase allowed differential staining of DNA and RNA with the nucleic acid dye 4',6-diamidino-2-phenylindole (DAPI). Epifluorescence microscopy revealed that the could-induced nonculturable populations of V. vulnificus are highly heterogeneous with regard to their nucleic acid content. The fraction of nonculturable cells which maintained DNA and RNA structures decreased gradually during cold incubation. After 5 months at 5 degrees C, less than 0.05% of the cells could be observed to retain DNA and RNA. In parallel with the loss of nucleic acids, an increase in the concentrations of UV-absorbing material in the culture supernatants was observed in nonculturable-cell suspensions. It is hypothesized that there are two phases of the formation of nonculturable cells of V. vulnificus: the first involves a loss of culturability with maintenance of cellular integrity and intact RNA and DNA (and thus possibly viability), and the second is typified by a gradual degradation of nucleic acids, the products of which partly remain inside the cells and partly diffuse into the extracellular space. A small number of nonculturable cells, however, retain DNA and RNA, and thus may be viable despite having reduced culturability.
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PMID:In situ analysis of nucleic acids in cold-induced nonculturable Vibrio vulnificus. 921 22

Different preparations of human rhinovirus serotype 2 (HRV2), a common cold virus, were analyzed by capillary zone electrophoresis (CZE) in untreated fused-silica capillaries using borate buffer (100 mmol/L, pH 8.3) and sodium dodecyl sulfate (10 mmol/L) as additive to prevent wall adsorption. The electropherograms showed one major peak at 205- and 254-nm detection wavelengths. The identity of the peak as originating from native virus was confirmed by several indirect methods. Heating to 56 degrees C is known to lead to release of the genomic RNA from the viral capsid; this treatment resulted in the disappearance of the major peak and the emergence of a new predominant peak that was identified as RNA by enzymatic digestion. As expected, RNase treatment of the unheated sample remained without effect as the viral genome is inaccessible in the native viral shell. A monoclonal, virus-aggregating antibody was used for immunodepletion of native virus; again, the major peak disappeared upon removal of viral aggregates by centrifugation prior to CZE analysis. In combination, these results allowed for the unambiguous identification of the main peak as native HRV2 and of the minor peaks as contaminants present in various amounts in the different viral preparations. It is demonstrated that CZE allows for an extremely easy and rapid assessment of conformational state and purity of virions in a given viral preparation.
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PMID:Analysis of common cold virus (human rhinovirus serotype 2) by capillary zone electrophoresis: the problem of peak identification. 1036 2

In response to stress, adrenocorticotropin (ACTH) is secreted from anterior pituitary corticotropes. Corticotropin-releasing hormone (CRH) is a potent stimulator of ACTH secretion. The CRH stimulation of secretion is mediated by cAMP and is largely dependent on Ca(2+) influx through voltage-gated L-type Ca(2+) channels. This study was designed to investigate whether the expression of L-type Ca(2+) channels in the rat anterior pituitary and in corticotropes is regulated by acute stress and CRH. RNase protection assays were used to quantify alpha(1C) mRNA of the L-type Ca(2+) channel. The alpha(1C) mRNA levels from stressed rats increased by 31% in anterior pituitaries of rats after 30 min of exposure to cold stress. Neither 60 min cold stress nor 30 min restraint stress had an effect on alpha(1C) mRNA levels. When alpha(1C) mRNA was detected by in situ hybridization in a population of corticotropes enriched to 90%, 0.5 nM CRH (3 h) stimulated a 36% increase in the average area of label/cell and a 10% increase in the average density of label. Our results suggest that (1) the expression of alpha(1C) subunit mRNA of L-type Ca(2+) channels is increased in the rat anterior pituitary with a stress-specific response that might reflect an increase both in thyrotropes and corticotropes (both are known to be stimulated by cold stress), and (2) the CRH-mediated increase in alpha(1C) mRNA expression in individual rat corticotropes, in vitro, supports the hypothesis that some of the increase in vivo is due to changes in corticotropes.
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PMID:Cold stress and corticotropin-releasing hormone induced changes in messenger ribonucleic acid for the alpha(1)-subunit of the L-type Ca(2+) channel in the rat anterior pituitary and enriched populations of corticotropes. 1042 89

Localization of bicoid (bcd) mRNA to the anterior and oskar (osk) mRNA to the posterior of the Drosophila oocyte is critical for embryonic patterning. Previous genetic studies implicated exuperantia (exu) in bcd mRNA localization, but its role in this process is not understood. We have biochemically isolated Exu and show that it is part of a large RNase-sensitive complex that contains at least seven other proteins. One of these proteins was identified as the cold shock domain RNA-binding protein Ypsilon Schachtel (Yps), which we show binds directly to Exu and colocalizes with Exu in both the oocyte and nurse cells of the Drosophila egg chamber. Surprisingly, the Exu-Yps complex contains osk mRNA. This biochemical result led us to reexamine the role of Exu in the localization of osk mRNA. We discovered that exu-null mutants are defective in osk mRNA localization in both nurse cells and the oocyte. Furthermore, both Exu/Yps particles and osk mRNA follow a similar temporal pattern of localization in which they transiently accumulate at the oocyte anterior and subsequently localize to the posterior pole. We propose that Exu is a core component of a large protein complex involved in localizing mRNAs both within nurse cells and the developing oocyte.
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PMID:Isolation of a ribonucleoprotein complex involved in mRNA localization in Drosophila oocytes. 1066 70

Treatment of Drosophila melanogaster adults with an inhibitor of protein synthesis led to a decrease in intrinsic cold-shock tolerance, but no difference in the rapid cold hardening response, which is apparent only if a period at 4 degrees C precedes the cold stress. Increases in energy reserves, including proline, were found in lines of flies selected for resistance to chilling injury. Since an increase in proline levels has been associated with overwintering in insects, and for salt and cold tolerance in plants, an RNase protection assay was developed to assess changes in transcript abundance for two genes encoding enzymes important for proline metabolism, pyrroline 5-carboxylate reductase and proline oxidase. The mRNA levels did not change in response to low temperature, but the high level of pyrroline 5-carboxylate reductase transcript is consistent with the interpretation that a large proline pool is important for Drosophila metabolism and survival during cold stress.
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PMID:Cold tolerance and proline metabolic gene expression in Drosophila melanogaster. 1116 4

The standard practice of tissue fixation in 10% formalin followed by embedding in paraffin wax preserves cellular morphology at the expense of availability and quality of DNA and RNA. The negative effect on cellular constituents results from a combination of extensive cross-linking and strand scission of DNA, RNA, and proteins induced by formaldehyde as well as RNA loss secondary to ubiquitous RNase activity and negative effects of high temperature exposure during paraffin melting, microscopic section collection, and tissue adherence to glass slides. An effective strategy to correlate cellular phenotype with molecular genotype involves microdissection of tissue sections based on specific histopathological features followed by genotyping of minute representative samples for specific underlying molecular alterations. Currently, this approach is limited to short-length polymerase chain reaction amplification (<250 bp) of DNA, due to the negative effects of standard tissue fixation and processing. To overcome this obstacle and permit both cellular morphology and nucleic acid content to be preserved to the fullest extent, we instituted a system of cold-temperature plastic resin embedding based on the use of the water-miscible methyl methacrylate polymer known as Immunobed (Polysciences, Warminster, PA). The system is simple, easy to adapt to clinical practice, and cost-effective. Immunobed tissue sections demonstrate a cellular appearance equivalent or even superior to that of standard tissue sections. Moreover, thin sectioning (0.5-1.0 microm thickness) renders ultrastructural evaluation feasible on plastic-embedded blocks. Tissue microdissection is readily performed, yielding high levels of long DNA and RNA for genomic and transcription-based correlative molecular analysis. We recommend the use of Immunobed or similar products for use in molecular anatomical pathology.
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PMID:Cold-temperature plastic resin embedding of liver for DNA- and RNA-based genotyping. 1127 4

Clinical and experimental data suggest a low thyroid hormone synthesis in cold thyroid nodules (CTN). Therefore, the Na(+)/I(-)-symporter (NIS) as the first step in the thyroid hormone synthesis could be a possible candidate gene in the pathogenesis of CTNs. A reduction of NIS transcripts in CTNs compared to samples of normal thyroid tissues with large inter-individual variations ranging from 2- to 700-fold reductions was observed with real-time RT-PCR. Therefore, the aim of our investigations was to perform an intra-individual comparison of NIS expression in CTNs. Moreover, we used direct detection of NIS mRNA by RNase protection assay (RPA). We investigated 14 patients with one CTN for NIS mRNA expression. NIS mRNA transcripts from nodule and surrounding tissue were examined by RPA. A significantly reduced NIS expression was detected in 86% of the CTNs compared to their corresponding surrounding tissue. The level of NIS expression was decreased to more than 65% in 10 CTNs (72% of the nodules). Two of the 14 nodules showed a decrease of NIS mRNA expression of 42%, and 32%, while no significant differences could be detected in 2 cold nodules. Compared to other studies the intra-individual comparison of NIS mRNA expression revealed a much lower variation of reduced NIS expression in CTNs. Further studies should try to identify molecular factors like post-transcriptional modifications or alterations in iodide organification which are likely to be involved in the pathogenesis of CTNs.
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PMID:Sodium/iodide symporter mRNA expression in cold thyroid nodules. 1157 39

During the past few years, our knowledge of gene regulation by RNA-binding proteins has greatly increased. RNA-binding proteins are involved in processes such as protection of RNAs from RNase degradation, prevention of ribosome binding to mRNA, control of formation of secondary structures of the mRNA that permit or prevent translation initiation, and termination/antitermination of transcription in response to external signals. Modulation of transcription termination by RNA-binding proteins involves the formation of alternative structures. One of the structures can act as a transcriptional terminator, while adoption of the alternative structure prevents formation of the terminator and does thus result in transcript elongation. Which of the two structures prevails under a given condition depends on two factors: the intrinsic stability of the alternative structures and the stabilization of one of both by an RNA-binding regulatory protein. Binding of a protein to the nascent mRNA may result in transcript elongation, as is the case for cold-shock proteins or in several catabolic operons. The RNA-binding ability of the RNA-binding proteins is modulated by direct interaction with the inducer, by protein-protein interactions with sensor proteins or by protein phosphorylation. In contrast, in the pyrimidine or tryptophan biosynthetic operons of Bacillus subtilis, the transcriptional terminators are stabilized by RNA-binding proteins resulting in the absence of expression of these operons.
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PMID:Control of transcription termination in bacteria by RNA-binding proteins that modulate RNA structures. 1202 88


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