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Rhinovirus detection: comparison of real-time and conventional PCR.

Rhinoviruses are important human respiratory viruses and the major causative agents of the common cold. Historically, detection of rhinovirus has been by virus culture and this was significantly improved by the use of PCR assays. Recently real-time PCR was developed but to date there have been no reported comparisons of conventional and real-time PCR assays for detection of rhinovirus. In this study, we first compared real-time PCR (SYBR Green I) to conventional PCR for the detection of rhinovirus in serially diluted standard DNA and rhinovirus stock to determine the limits of detection. Next, assays were compared for sensitivity to detect rhinovirus in cell culture with a known number of infected cells. Finally, the assays were compared using clinical samples known to contain rhinovirus. Real-time PCR was 10-fold more sensitive than conventional PCR to detect rhinovirus in standard DNA and in virus stock and >10-fold more sensitive to detect rhinovirus in cultured cells. Real-time PCR was significantly superior for detection of rhinovirus in patients' nasal aspirates (sensitivity 72% versus 39%, P < 0.05). In summary, we found that real-time PCR was more sensitive than conventional PCR and reduced post-PCR processing. Hence, real-time PCR is suitable for both research and clinical purposes.

Common Cold↗

Expression of the catalytic subunit associated with telomerase gene in human urinary bladder cancer.

PURPOSE: Telomerase is the ribonucleoprotein enzyme associated with the immortalization and oncogenesis of cancer cells. To examine the expression of two major components of the telomerase associated gene, hEST2/hTRT and TLP1/TP1, in urinary bladder carcinogenesis, we studied 27 human urinary bladder cancers using the reverse transcriptase-polymerase chain reaction (RT-PCR) method. MATERIALS AND METHODS: Total RNAs were obtained from 27 urinary bladder cancer and 23 normal bladder tissues using surgical removal or the cold cup bioptical method. The cDNA was then synthesized from these total RNAs, and hTRT and TP1 mRNA were amplified using the RT-PCR method. RESULTS: hEST2/hTRT expression was detected in all 27 (100%) cases. However, TLP1/TP1 was detected in 25 of 27 (93%) cases. The correlation between these expressions and clinicopathological characteristics such as tumor grade, clinical stage, and histological type showed no statistical significance. Twenty-three cases of normal bladder tissues showed no expression of hEST2/hTRT, but 18 of 23 (78%) cases showed TLP1/TP1 expression. CONCLUSIONS: These findings indicate that the up-regulation of hEST2/hTRT gene expression may play a critical role in carcinogenesis of human urinary bladder cancers. RT-PCR for detecting expression of hEST2/hTRT gene is a powerful method for the screening and diagnosis of urinary bladder cancer.

Adult↗

Microbial diversity in smoked salmon examined by a culture-independent molecular approach--a preliminary study.

Microbial biodiversity in sliced vacuum-packed cold smoked salmon was investigated using culture-independent molecular biology techniques. Sliced smoked salmon was stored for 25 days after being packed at 4 degrees C. DNA was extracted from sliced vacuum-packed cold smoked salmon. PCR DNA amplification were carried out using universal eubacterial primers corresponding to Escherichia coli 16S rRNA gene. 16S rRNA genes were amplified, cloned in E. coli and compared using Amplification Ribosomal DNA Restriction Analysis (ARDRA). 106 clones were studied and classified into 13 Operational Taxonomic Units (OTUs). Sequences obtained to describe those 13 OTUs were compared to GenBank data. They indicated the presence of Vibrio species. Enterobacteraceae and also marine psychrophilic clones related to Alteromonas macleodii, which were not encountered within cultures, but no Gram-positive species have been obtained. Those results indicate that bias in description of microbial diversity may be encountred in both molecular and cultural techniques.

Bacteria↗

Abattoir sources of psychrophilic clostridia causing blown pack spoilage of vacuum-packed chilled meats determined by culture-based and molecular detection procedures.

AIMS: To identify the abattoir source(s) of psychrophilic clostridia causing 'blown pack' spoilage of vacuum-packed chilled meats. METHODS AND RESULTS: Molecular procedures were used to detect the presence of specific 16S rRNA gene fragments of blown pack-causing clostridia in samples collected from a commercial abattoir and its environs. Blown pack-causing clostridia were consistently detected in hide, soil and faecal samples, as well as in samples collected at slaughter plant locations associated with handling of animals and animal carcasses prior to pelt removal. CONCLUSIONS: The data indicate that pelts per se or soil particles/faecal material attached thereto are the most probable primary reservoir of blown pack clostridia in the abattoir. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper provides information critical for controlling blown pack spoilage in commercial meat-processing plants.

Abattoirs↗

Comparison of the stress response to cryopreservation in monolayer and three-dimensional human fibroblast cultures: stress proteins, MAP kinases, and growth factor gene expression.

Stress responses induced in fibroblasts by cryopreservation were compared in suspension or three-dimensional cultures at various times up to 5 days of recovery. Cryopreservation caused an 86% inhibition in [(35)S]methionine incorporation, with recovery over 2 days to 45% &plusmn: 14% of its original value. Stress proteins, including heat shock protein (hsp) and glucose-regulated proteins (GRP), detected by immunoblotting, responded with transient increases in cellular content (hsp27 and hsp90 in suspension and three-dimensional culture, and hsp70 only in three-dimensional culture), decreases at 24 h (hsp56, hsp70, hsp90, and GRP78 in three-dimensional culture and hsp90 in suspension), or little change (hsp70 in suspension). Polyacrylamide gel electrophoresis of [(35)S]methionine-labeled proteins showed transient induction of hsp47 within 4 h, and increased synthesis of hsp90 and GRP78 and other unidentified proteins at 24 h, but no change in hsp70. The mitogen-activated protein (MAP) kinase, p38, showed a transient increase after thawing, followed by a peak in extracellular signal-regulated kinase at 24 h. The stress-activated protein kinase (JNK) was not activated. In both stress protein and MAP kinase responses, the three-dimensional cultures showed a more intense response than fibroblasts in suspension. Although some responses were related to osmotic and cold stress during freezing, others were unique. Cryopreservation induced mRNA for selected growth factors, including vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) A chain, which increased 5- to 20- fold at 48 h returning to basal levels by 120 h. Our results indicate the novel finding that cryopreservation of fibroblasts grown in three-dimensional culture induced a specific cellular stress response including growth factors.

Cell Culture Techniques↗

A cold-sensitive Listeria monocytogenes mutant has a transposon insertion in a gene encoding a putative membrane protein and shows altered (p)ppGpp levels.

A cold-sensitive Listeria monocytogenes mutant designated cld-14 was obtained by transposon Tn917 mutagenesis. The gene interrupted by Tn917 in cld-14 was the L. monocytogenes LMOf2365_1485 homolog, which exhibits 45.7% homology to the Bacillus subtilis yqfF locus. LMOf2365_1485, here designated pgpH, encodes a putative integral membrane protein with a predicted molecular mass of 81 kDa. PgpH is predicted to contain a conserved N-terminal signal peptide sequence, seven transmembrane helices, and a hydrophilic C terminus, which likely extends into the cytosol. The Tn917 insertion in pgpH is predicted to result in production of a premature polypeptide truncated at the fifth transmembrane domain. The C terminus of PgpH, which is probably absent in cld-14, contains a highly conserved HD domain that belongs to a metal-dependent phosphohydrolase family. Strain cld-14 accumulated higher levels of (p)ppGpp than the wild type accumulated, indicating that the function of PgpH may be to adjust cellular (p)ppGpp levels during low-temperature growth. The cld-14pgpH(+) complemented strain was able to grow at a low temperature, like the parent strain, providing direct evidence that the activity of PgpH is important in low-temperature adaptation. Because of its predicted membrane location, PgpH may play a critical role in sensing the environmental temperature and altering cellular (p)ppGpp levels to allow the organism to adapt to low temperatures.

Bacterial Proteins↗

Detection of rhinovirus infection of the nasal mucosa by oligonucleotide in situ hybridization.

Human rhinoviruses (HRVs) cause the common cold and often induce lower airway symptoms such as cough and wheezing. Although HRV infection is presumed to involve primarily ciliated epithelial cells, this has not been confirmed in vivo, and the cellular distribution and spread of infection as well as the pathogenesis of cold related nasal and chest symptoms remain speculative. We have developed in situ hybridization (ISH) to explore localization of the virus to airway tissues, employing HRV 16-derived oligonucleotide probes after sequencing part of the genome of this serotype. A reverse transcription-polymerase chain reaction was used to generate DNA from HRV 16 for sequencing; this yielded 305 nucleotide bases that showed considerable homology to other HRVs. The HRV 16 sequence was used to design oligonucleotides functioning as antisense and sense probes. These probes as well as random sequence and pathogen control oligonucleotides were applied to HRV-infected cell-clot complexes and finally to sections from six paired nasal biopsies obtained before, during, or after HRV-proven colds. Specificity of hybrids was established by the absence of signal in uninfected tissue, in cells infected with other viruses, after RNase pretreatment, and with application of control probes. Hybridization signals were observed in epithelial cells in three of six biopsies obtained during a cold, using probes to viral (+) strand; intermediate (-) strand, implying viral replication, was present in one biopsy. Evidence for infection of nonepithelial cells was inconclusive. HRVs cause productive infection of nasal epithelium during a cold and their intracellular localization may produce perturbation of inflammatory mediators and cytokine profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

Validity of function tests on the upper extremities in establishing a prognosis in vibration syndrome.

The validity of function tests on the upper extremities as prognostic tools in vibration syndrome was evaluated over a sequence of observation periods. The subjects examined were 672 forest workers using chain saws who had had some complaints and who had shown abnormal findings in the function tests. The function tests consisted of peripheral circulatory and sensory tests, including cold provocation and motor tests of functional capacity in the upper extremities. From the results of testing, 23 variables were selected and examined by multivariate analysis. The four principal components were extracted by principal component analysis, and the factor score of the peripheral circulatory disturbances component was found to be highly correlated with the severity of VWF (Vibration-induced White Finger). The course of VWF and the nail compression test had high standard regression coefficients with the severity of vibration syndrome. The course of finger numbness, pinching power, pain threshold, skin temperature and X-ray findings in the elbow joints had high discriminant function values for the evaluation of the severity of vibration syndrome.

Discriminant Analysis↗

Plasticity of myosin heavy chain expression with temperature acclimation is gradually acquired during ontogeny in the common carp (Cyprinus carpio L.).

Common carp (Cyprinus carpio L.) were reared from hatching until 61 mm total length (TL) at 21 degrees C. At 14 weeks and 20 weeks post-hatch, corresponding to initial lengths of 30 mm and 44 mm respectively, fish were acclimated to 10 degrees C using a rate of cooling of 1 degrees C per day. A statistical model was used to compare the time course in the change of white muscle myofibrillar ATPase activity with temperature acclimation. The myosin heavy chain (MHC) composition of white muscle myofibrils was investigated using peptide mapping. A significant increase in myofibrillar ATPase activity was observed after 2-3 weeks in the 44 mm group, but not until 4-5 weeks in the 30 mm group. when they had reached 37 mm TL. The MHC banding pattern of 120 mm TL fish acclimated to 10 degrees C or 21 degrees C for a minimum of 6 weeks were distinct from each other. The MHC peptide map characteristic of 10-degrees C-acclimated fish was not observed in individuals less than 37 mm length. We therefore conclude that the capacity to alter the composition and properties of myofibrils with cold acclimation is acquired in juvenile carp at around 37 mm TL.

Acclimatization↗

[Lipids, depression and suicide].

Polyunsatured fatty acids are made out of a hydrocarbonated chain of variable length with several double bonds. The position of the first double bond (omega) differentiates polyunsatured omega 3 fatty acids (for example: alpha-linolenic acid or alpha-LNA) and polyunsatured omega 6 fatty acids (for example: linoleic acid or LA). These two classes of fatty acids are said to be essential because they cannot be synthetised by the organism and have to be taken from alimentation. The omega 3 are present in linseed oil, nuts, soya beans, wheat and cold water fish whereas omega 6 are present in maize, sunflower and sesame oil. Fatty acids are part of phospholipids and, consequently, of all biological membranes. The membrane fluidity, of crucial importance for its functioning, depends on its lipidic components. Phospholipids composed of chains of polyunsatured fatty acids increase the membrane fluidity because, by bending some chains, double bonds prevent them from compacting themselves perfectly. Membrane fluidity is also determined by the phospholipids/free cholesterol ratio, as cholesterol increases membrane viscosity. A diet based on a high proportion of essential polyunsatured fatty acids (fluid) would allow a higher incorporation of cholesterol (rigid) in the membranes to balance their fluidity, which would contribute to lower blood cholesterol levels. Brain membranes have a very high content in essential polyunsatured fatty acids for which they depend on alimentation. Any dietary lack of essential polyunsatured fatty acids has consequences on cerebral development, modifying the activity of enzymes of the cerebral membranes and decreasing efficiency in learning tasks. EPIDEMIOLOGICAL DATA: The prevalence of depression seems to increase continuously since the beginning of the century. Though different factors most probably contribute to this evolution, it has been suggested that it could be related to an evolution of alimentary patterns in the Western world, in which polyunsatured omega 3 fatty acids contained in fish, game and vegetables have been largely replaced by polyunsatured omega 6 fatty acids of cereal oils. Some epidemiological data support the hypothesis of a relation between lower depression and/or suicide rates and a higher consumption of fish. These data do not however prove a relation of causality. CHOLESTEROL AND DEPRESSION: Several cohort studies (on nondepressed subjects) have assessed the relationship between plasma cholesterol and depressive symptoms with contradictory results. Though some results found a significant relationship between a decrease of total cholesterol and high scores of depression, some other did not. Studies among patients suffering from major depression signalled more constantly an association between low cholesterol and major depression. Besides, some trials showed that clinical recovery may be associated with a significant increase of total cholesterol. CHOLESTEROL AND SUICIDAL BEHAVIOR: The hypothesis that a low cholesterol level may represent a suicidal risk factor was discovered accidentally following a series of epidemiological studies which revealed an increase of the suicidal risk among subjects with a low cholesterol level. Though some contradictory studies do exist, this relationship has been confirmed by several subsequent cohort studies. These findings have challenged the vast public health programs aimed at promoting the decrease of cholesterol, and even suggested to suspend the administration of lipid lowering drugs. Recent clinical studies on populations treated with lipid lowering drugs showed nevertheless a lack of significant increase of mortality, either by suicide or accident. In addition, several controlled studies among psychiatric patients revealed a decrease of the concentrations of plasma cholesterol among patients who had attempted suicide in comparison with other patients. POLYUNSATURATED FATTY ACID AND DEPRESSION: In major depression, all studies revealed a significant decrease of the polyunsaturated omega 3 fatty acids and/or an increase of the omega 6/omega 3 ratio in plasma and/or in the membranes of the red cells. In addition, two studies found a higher severity of depression when the level of polyunsaturated omega 3 fatty acids or the ratio omega 3/omega 6 was low. Parallel to these modifications, other biochemical perturbations have been reported in major depression, particularly an activation of the inflammatory response system, resulting in an increase of the pro-inflammatory cytokines (interleukins: IL-1b, IL-6 and interferon g) and eicosanoids (among others, prostaglandin E2) in the blood and the CSF of depressed patients. These substances cause a peroxidation and, consequently a catabolism of membrane phospholipids, among others those containing polyunsaturated fatty acids. The cytokines and eicosanoids derive from polyunsaturated fatty acids and have opposite physiological functions according to their omega 3 or omega 6 precursor. Arachidonic acid (omega 6) is, among others, precursor of pro-inflammatory prostaglandin E2 (PGE2), whereas polyunsaturated omega 3 fatty acids inhibit the formation of PGE2. It has been shown that a dietary increase of polyunsaturated omega 3 fatty acids reduced strongly the production of IL-1 beta, IL-2, IL-6 and TNF-alpha (tumor necrosis factor-alpha). In contrast, diets with a higher supply of linoleic acid (omega 6) increased significantly the production of pro-inflammatory cytokines, like TNF-alpha. Therefore, polyunsaturated omega 3 fatty acids could be associated at different levels in the pathophysiology of major depression, on the one hand through their role in the membrane fluidity which influences diverse steps of neurotransmission and, on the other hand, through their function as precursor of pro-inflammatory cytokines and eicosanoids disturbing neurotransmission. In addition, antidepressants could exhibit an immunoregulating effect by reducing the release of pro-inflammatory cytokines, by increasing the release of endogenous antagonists of pro-inflammatory cytokines like IL-10 and, finally, by acting like inhibitors of cyclo-oxygenase. THERAPEUTIC USE OF FATTY ACIDS: Data available concerning the administration of supplements of DHA (docosahexanoic acid) or other polyunsaturated fatty acids omega 3 are limited. In a double blind placebo-controlled study on 30 patients with bipolar disorder, the addition of polyunsaturated omega 3 fatty acids was associated with a longer period of remission. Moreover, nearly all the other prognosis measures were better in the omega 3 group. Very recently, a controlled trial showed the benefits of adding an omega 3 fatty acid, eicosopentanoic acid, among depressed patients. After 4 weeks, six of the 10 patients receiving the fatty acid were considered as responders in comparison with only one of the ten patients receiving placebo. CONCLUSIONS: Some epidemiological, experimental and clinical data favour the hypothesis that polyunsaturated fatty acids could play a role in the pathogenesis and/or the treatment of depression. More studies however are needed in order to better precise the actual implication of those biochemical factors among the various aspects of depressive illness.

Adolescent↗

Regulation of coronary myoplasmic Ca(2+)-myosin light chain phosphorylation pathway and vasomotor tone: hyperpolarizing versus depolarizing cardioplegia.

BACKGROUND: This study was designed to compare the effects of hyperpolarizing versus depolarizing cardioplegic solutions on the coronary vasomotor regulation, specifically focusing on coronary myoplasmic Ca2+-myosin light chain (MLC) phosphorylation pathway and beta-adrenergic signal transduction. METHODS: With the use of an in vitro cardioplegic model, rat coronary microvessels loaded with fura-2 were subjected to simulated cold (20 degrees C) cardioplegia and reperfused with Krebs solution for 60 minutes at 37 degrees C. Cardioplegia consisted of either (1) Krebs solution alone (control), (2) Krebs plus adenosine triphosphate-sensitive potassium channel opener (100 micromol/L pinacidil [PCO-CP]), (3) hyperkalemic cardioplegia (K(+) = 25 mmol/L [K-CP]), or (4) K-CP plus magnesium (Mg(2+) = 25 mmol/L; [K/Mg-CP]). RESULTS: At the endpoint of the cardioplegic period, K-CP resulted in a significant increase both in [Ca(2+)](i) and in MLC phosphorylation compared with control (both P <.05). In contrast, PCO-CP did not make any significant difference in these indices compared with control. After reperfusion, the relaxation responses to isoproterenol and forskolin after K-CP were significantly reduced (both P <.05 vs control) but were preserved after PCO-CP. K/Mg-CP provided comparable effects to PCO-CP. CONCLUSIONS: These results suggest that neither an activation of the coronary myoplasmic Ca(2+)-MLC phosphorylation pathway nor beta-adrenergic desensitization seen after exposure to depolarizing cardioplegia occurs with exposure to hyperpolarizing cardioplegia and magnesium-supplemented depolarizing hyperkalemic cardioplegia.

Animals↗

Circulating immunoglobulin complexes in Wegener's granulomatosis.

Two cases of Wegener's granulomatosis are reported in which circulating immunoglobulin complexes detected during the active phase of the disease disappeared during induction of remissions of active pulmonary and renal disease by immunosuppressive agents. Elevated antiglobulin activity, urinary immunoglobulin L-chain concentration and evidence of activated coagulation mechanisms were also present during active disease, and returned toward normal with treatment. Studies showed that the serum complexes did not contain deoxyribonucleic acid (DNA) and demonstrated their immunoglobulin nature. Serum complement concentrations were normal, and no cryoglobulins were present. Immunofluorescent staining and electron microscopy of the kidney biopsy specimen of one patient showed marked fibrin deposition but no immunoglobulin or antigen-antibody deposits. Although the role of circulating immunoglobulin complexes in the pathogenesis of Wegener's granulomatosis remains uncertain, serial changes in the described parameters may provide an objective guide to activity of the disease and its response to treatment.

Adult↗

[Cold deformation elements for attaching an implantable hearing aid transducer to ear ossicles or perilymph].

Development and short-term implantation results of the Tübingen implantable hearing aid (TI = Tübingen implant) have been presented. The TI is designed for patients with sensorineural hearing loss due to a malfunction of the cochlear amplifier. This can be identified by the presence of positive recruitment and the absence of TEOAE (transitory evoked otoacoustic emissions). The Tübingen implant functions in two ways: it allows electronic amplification of the auditory signal and electromechanical signal transduction into a micromechanical vibratory stimulus. There are two paths by which vibratory stimulus reaches the cochlea: (1) directly through a perforation in the stapes foot plate into the perilymph or (2) via the ossicular chain. Made of pure titanium, the casing of the helium-tight welded transducer includes the piezoelectric actuator. An implantable manipulator device is designed for transducer positioning and anchoring in the mastoid cavity. Usually, the transducer probe tip is directly coupled to the body of the incus. This functions without a special coupling device by utilization of an Erbium-YAG laser. Special anatomical situations or the loss of incus and/or stapes suprastructure, however, requires coupling of the vibratory signal to other points of the ossicular chain or to the perilymph. A major problem, however, was an intraoperative, irreversible link between the titanium probe tip and coupling elements. To overcome this problem, the coupling elements were made of gold. A crimp technique was developed, allowing the surgeon to induce cold deformation of the gold. The cold deformation technique (crimp) results in an irreversible coupling between the titanium probe tip and the golden coupling element.

Cochlear Implantation↗

Sensitivities of the alternative respiratory components of potato tuber mitochondria to thiol reagents and Ca2+.

Plant mitochondria differ from those of mammals, since they incorporate an alternative electron transport pathway, which branches at ubiquinol to an alternative oxidase (AOX), characteristically inhibited by salicylhydroxamic acid (SHAM). Another feature of plant mitochondria is that besides complex I (EC 1.6.5.3) they possess alternative NAD(P)H-dehydrogenases insensitive to rotenone. Many stress conditions are known to alter the expression of the alternative electron transport pathway in plant mitochondria. In the present study we investigated the effects of some thiol reagents and Ca(2+) on potato mitochondrial respiratory chain presenting different activities of the alternative respiratory components AOX and external NADH dehydrogenase, a condition induced by previous treatment of potato tubers (Solanum tuberosum L., cv. Bintje) to cold stress. The results showed that Ca(2+) presented an inhibitory effect on AOX pathway in potato mitochondria energized with NADH or succinate, which was only now observed when the cytochrome pathway was inhibited by cyanide. When the cytochrome pathway was functional, Ca(2+) stimulated the external NADH dehydrogenase. Diamide was a potent AOX inhibitor and this effect was only now observed when the cytochrome pathway was inactive, as was the case for the calcium ion. Mersalyl inhibited the externally located NADH dehydrogenase and had no effect on AOX activity. The results may represent an important function of Ca(2+) on the alternative mitochondrial enzymes NADH-DH(ext) and AOX.

Calcium↗

Magnesium deficiency in human subjects--a personal historical perspective.

Over the past 30 years human magnesium (Mg) deficiency has become an accepted fact in most medical circles. Our index patient had striking neurological manifestations including generalized tremulousness, grimaces and fibrillary twitches of facial muscles, athetoid and choreiform movements of upper extremities, dysphagia, inability to speak, repeated convulsions, and confusion. She had received glucose in water and saline intravenously for several months. A patient with chronic alcoholism was noted to have almost identical symptoms and signs as the index patient. He also responded dramatically to MgSO4 injections. This resulted in a series of studies on patients with chronic alcoholism. The evidence of Mg deficiency in alcoholism includes the following: significant hypomagnesemia, strongly positive Mg balance during recovery, significant decrease in muscle Mg, a deficit of total exchangeable 28Mg quantitatively similar to deficit by balance studies, often a dramatic response of symptoms to therapy with Mg, and diuresis of Mg produced by ingestion of alcohol. Lipolysis with high levels of long-chain free fatty acids (FFA) occurs in withdrawal of alcohol in chronic alcoholism, withdrawal of certain addictive drugs, after trauma, surgery, administration of adrenergic compounds or theophylline, exposure to cold, and an adverse environment as in grass staggers. Concentrations of Mg fall when FFA increase in all of the above circumstances. This phenomenon has wide implications in health and disease. Better awareness of Mg deficiency in a wide variety of clinical conditions will result in life-saving treatment and less morbidity of other patients.

Adolescent↗

Solution NMR structure of the cold-shock protein from the hyperthermophilic bacterium Thermotoga maritima.

Cold-shock proteins (Csps) are a subgroup of the cold-induced proteins preferentially expressed in bacteria and other organisms on reduction of the growth temperature below the physiological temperature. They are related to the cold-shock domain found in eukaryotes and are some of the most conserved proteins known. Their exact function is still not known, but translational regulation, possibly via RNA chaperoning, has been discussed. Here we present the structure of a hyperthermophilic member of the Csp family. The NMR solution structure of TmCsp from Thermotoga maritima, the hyperthermophilic member of this class of proteins, was solved on the basis of 1015 conformational constraints. It contains five beta strands combined in two antiparallel beta sheets making up a beta barrel structure, in which beta strands 1-4 are arranged in a Greek-key topology. The side chain of R2, which is exclusively found in thermophilic members of the Csp family, probably participates in a peripheral ion cluster involving residues D20, R2, E47 and K63, suggesting that the thermostability of TmCsp is based on the peripheral ion cluster around the side chain of R2.

Amino Acid Sequence↗

Influence of cytoskeletal agents on the respiratory electron transport pathways in the cells of winter wheat leaves.

The effects of actin and tubulin polymerization inhibitors on the respiratory electron transport pathway activities were investigated using abscisic acid (ABA)- and cold-treated winter wheat seedling leaves. In unstressed control plants, cytochalasin B (15 microm) decreased the capacity of the cytochrome pathway, but stimulated the cyanide-resistant pathway, whereas oryzalin (15 microm) produced the opposite effects. Cold hardening (3 degrees C for 7 days) and ABA treatment 30 microm changed the respiratory pattern in a similar manner to cytochalasin B but to lesser effects. This points to cold- and ABA-induced reduction in microfilament sensitivity to these drugs and hence stabilization of actin-dependent processes. In contrast, oryzalin had only weak effects on control samples and its effects were strengthened in the presence of the cytoskeleton-modifying factors. The data suggest that the potential targets for the agent either increase and/or the degree of involvement of microtubules in the respiratory chain regulation, and therefore that the cytoskeleton can modify the functioning of the respiratory electron transport pathways in winter wheat cells.

Abscisic Acid↗