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PubMed2000

Cold acclimation or grapeseed oil feeding affects phospholipid composition and mitochondrial function in duckling skeletal muscle.

The phospholipid fatty acid (FA) composition and functional properties of skeletal muscle and liver mitochondria were examined in cold-acclimated (CA, 4 degrees C) ducklings. Phospholipid FA of isolated muscle mitochondria from CA birds were longer and more unsaturated than those from thermoneutral (TN, 25 degrees C) reared ducklings. The rise in long-chain and polyunsaturated FA (PUFA, mainly 20:4n-6) was associated with a higher State 4 respiration rate and a lower respiratory control ratio (RCR). Hepatic mitochondria, by contrast, were much less affected by cold acclimation. The cold-induced changes in phospholipid FA profile and functional properties of muscle mitochondria were reproduced by giving TN ducklings a diet enriched in grapeseed oil (GO, rich in n-6 FA), suggesting a causal relationship between the membrane structure and mitochondrial functional parameters. However, hepatic mitochondria from ducklings fed the GO diet also showed an enrichment in long-chain PUFA but opposite changes in their biochemical characteristics (lower State 4, higher RCR). It is suggested that the differential modulation of mitochondrial functional properties by membrane lipid composition between skeletal muscle and liver may depend on muscle-specific factors possibly interacting with long-chain PUFA and affecting the proton leakiness of mitochondrial membranes.

Animals↗
PubMedDate not supplied

[Effect of a culturing method and growth phase on composition of lipopolysaccharides in Yersinia pseudotuberculosis].

The effects of the culturing method (suspension cultures in a liquid nutrient broth or colonies on a solid agarized medium) and the growth phase on the lypopolysaccharide (LPS) composition of Yersinia pseudotuberculosis (O:Ib serovar, strain KS 3058) grown in cold (5 degrees C) were studied. The amount the LPS synthesized by cells depended on the bacteria growth phase for both media. The LPS acylation degree was constant, whereas the length of the O-specific polysaccharide chain varied with the culture age and achieved maximum in the stationary growth phase for both media. The bacteria culturing on the nutrient agar stimulated more intensive synthesis of LPS, which were extracted more easily, had longer polysaccharide O-chains, and were more toxic than LPS of the bacteria cultured in the liquid medium. It was proposed that the culturing of Yersinia pseudotuberculosis in cold as colonies on the agar surface causes an increase in the bacterial virulence.

Agar↗
PubMed1992

The amino acid sequence and oxygen-binding properties of the single hemoglobin of the cold-adapted Antarctic teleost Gymnodraco acuticeps.

The complete amino acid sequence of the single hemoglobin of the Antarctic teleost Gymnodraco acuticeps has been determined. The alpha chain contains 142 amino acid residues; an acetylated seryl residue is at the amino terminal. The beta chain contains 146 residues. A very high degree of sequence identity has been found with hemoglobins of other Antarctic fishes. Oxygen binding is not modulated by pH and allosteric effectors. The Bohr and Root effects are absent, although specific amino acid residues, considered responsible of most of these functions, are conserved in the sequence, thus posing new questions about the molecular basis of these mechanisms. The low heat of oxygenation may be interpreted as one of the mechanisms involved in the process of cold adaptation.

Adaptation, Physiological↗
PubMed1987

Avian sebokeratocytes and marine mammal lipokeratinocytes: structural, lipid biochemical, and functional considerations.

In terrestrial mammals, stratum corneum lipids derive from two sources: deposition of lamellar body lipids in stratum corneum interstices and excretion of sebaceous lipids onto the skin surface, resulting in a two-compartment ("bricks and mortar") system of lipid-depleted cells surrounded by lipid-enriched intercellular spaces. In contrast, intracellular lipid droplets, normally not present in the epidermis of terrestrial mammals, are prominent in avian and marine mammal epidermis (cetaceans, manatees). We compared the transepidermal water loss, ultrastructure, and lipid biochemistry of the viable epidermis and stratum corneum of pigeon apterium, fledgling (featherless) zebra finches, painted storks, cetaceans, and manatees to those of humans and mice. Marine mammals possess an even more extensive lamellar-body secretory system than do terrestrial mammals; and lamellar-body contents, as in terrestrials, are secreted into the stratum corneum interstices. In cetaceans, however, glycolipids, but not ceramides, persist into the stratum corneum; whereas in manatees, glycolipids are replaced by ceramides, as in terrestrial mammals. Acylglucosylceramides, thought to be critical for lamellar-body deposition and barrier function in terrestrial mammals, are present in manatees but virtually absent in cetaceans, a finding that indicates that they are not obligate constituents of lamellar-body-derived membrane structures. Moreover, cetaceans do not elaborate the very long-chain, saturated N-acyl fatty acids that abound in terrestrial mammalian acylglucosylceramides. Furthermore, cold-water marine mammals generate large, intracellular neutral lipid droplets not found in terrestrial and warm-water marine mammals; these lipid droplets persist into the stratum corneum, suggesting thermogenesis, flotation, and/or cryoprotectant functions. Avians generate distinctive multigranular bodies that may be secreted into the intercellular spaces under xerotic conditions, as in zebra fledglings; ordinarily, however, the internal lamellae and limiting membranes deteriorate, generating intracellular neutral lipid droplets. The sphingolipid composition of avian stratum corneum is intermediate between terrestrials and cetaceans (approximately equal to 50% glycolipids), with triglycerides present in abundance. In the midstratum corneum of avians, neutral lipid droplets are released into the interstices, forming a large extracellular, lipid-enriched compartment, surrounding wafer-thin corneocytes, with a paucity of both lipid and keratin ("plates-and-mortar" rather than the "bricks-and-mortar" of mammals).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2003

Cloning, heterologous expression, renaturation, and characterization of a cold-adapted esterase with unique primary structure from a psychrotroph Pseudomonas sp. strain B11-1.

A gene coding for an esterase (PsEst1, 1911bp in length) of the psychrotrophic bacterium Pseudomonas sp. B11-1 isolated from Alaskan soil was cloned and sequenced. The deduced amino acid sequence revealed a protein of 637 amino acid residues with a molecular mass of 69 kDa. Although the expression product, PsEst1, showed no appreciable sequence similarity (less than 15% identity) to any known proteins with the established biochemical functions, it is expected to be related to the alpha/beta hydrolase superfamily because it shared sequence motifs that have been identified with this superfamily. For example, a unique 'nucleophilic elbow' motif, -Gly(36)-Asp-Ser-Leu-Asn(40)-, was identified, and Ser(38) was predicted to constitute a catalytic triad with Asp(162) and His(303). PsEst1 was overexpressed using a T7 RNA polymerase transcription (pET21a) system in the Escherichia coli BL21(DE3) cells as an inclusion body. A soluble denatured form of the enzyme was purified to homogeneity in the presence of 8M urea, and the catalytically active form of the enzyme could be obtained by subsequent removal of urea by dialysis, where the addition of 0.1% Triton X-100 was essential for the efficient renaturation of the enzyme. To our knowledge, this was the first example of the successful renaturation of the recombinant cold-adapted enzyme. The enzyme efficiently hydrolyzed vinyl and aryl esters with the C4-C6 acyl chain. The activation energy of the enzymatic p-nitrophenyl butyrate hydrolysis (20.1 kcal/mol at 10 degrees C) was significantly lower than the value (79.9 kcal/mol) of the mesophilic lipase. It was observed that the K(m) values for p-nitrophenyl butyrate in the growth temperature range of strain B11-1 (5-15 degrees C) were lower than those at higher temperatures.

Adaptation, Physiological↗
PubMed1999

Percutaneous penetration of local anesthetic bases: pharmacodynamic measurements.

Local anesthetics do not penetrate readily through human skin if applied in their salt form; however, if applied in their base form various effects may be observed, such as a decrease in pricking pain and a change in burning, itch, and thermal sensations. These effects occur after skin penetration and may be attributed to the action of the anesthetics on nociceptors and thermoreceptors, i.e., on C and Adelta nerve fiber respectively. As there is little known about the time course of the pharmacodynamic response of cutaneously applied local anesthetic bases, this study was conducted to characterize various local anesthetics pharmacodynamically by measuring thermal thresholds over time with a thermal sensory analyzer. The results show that the investigated local anesthetics affect thermal thresholds to a different extent, with tetracaine and lidocaine being most efficient. From the response versus time profiles of all eight study subjects various response parameters were obtained: only the cold sensation parameters proved suitable for characterization of the local anesthetics, possibly because cold receptors are located in the epidermis and can easily be reached. Lag times of onset are short and the maximum anesthetic effect is reached within 2-3 h. Cold sensation parameters correlate linearly with the solubility of the local anesthetic bases in medium chain triglycerides and with the drug flux of 50% saturation, indicating that medium chain triglycerides may have similar properties with regard to the local anesthetics solubility as the stratum corneum lipids.

Anesthetics, Local↗
PubMed2005

Effects of cold-water immersion on VEGF mRNA and protein expression in heart and skeletal muscles of rats.

AIM: The effects of cold exposure on gene and protein expression of vascular endothelial growth factor (VEGF), in heart and skeletal muscles, were studied in male adult Wistar rats. METHODS: Cold immersion was accomplished by submerging the rats in shoulder-deep water maintained at approximately 18 degrees C, either acutely (1 h) or chronically (1 h day(-1), 5 days week(-1) for 20 weeks). The expressions of VEGF mRNA and protein in heart, gastrocnemius, and soleus muscles were examined by Northern and Western blotting and competitive-polymerase chain reaction techniques. RESULTS: The expressions of VEGF mRNA and protein were markedly increased in cardiac muscle of the cold-immersed group, particularly in the 1-hour exposure group, whereas VEGF mRNA and protein in gastrocnemius were decreased significantly after an acute exposure. Although the protein level in gastrocnemius remained low in the chronically exposed group, the expression of mRNA of VEGF(165) with chronic exposure in this group returned to the control level and that of VEGF(206) was 15% greater than that in controls. The expression of mRNA for VEGF(165) in soleus was also lowered by acute cold exposure, although that for VEGF(206) was stable. However, VEGF protein was increased by 50%. After 20 weeks, all of these parameters were increased over the levels found in the controls. CONCLUSION: These results suggest that the VEGF gene may be a major regulatory factor in cardiac and skeletal muscle adaptation to the cold environment stimulating angiogenesis and thermogenesis.

Actins↗
PubMed1975

Renal pathologic findings associated with monoclonal gammopathies.

The myeloma kidney is characterized by casts in the distal and collecting tubules. The glomeruli are hardly affected unless amyloidosis is present. When the glomeruli are involved, the proteinuria is nonselective and, in some cases, the whole paraprotein is excreted in the urine. Nephrocalcinosis may be present and focal myeloma cell infiltration in the interstitium is a characteristic, but inconstant, finding. The nephrotic syndrome is extremely rare; if it exists, amyloidosis should be suspected. In contrast to multiple myeloma, the glomeruli are frequently involved in macroglobulinemia of Waldenstrom. Hyaline intracapillary deposits consisting of pure IgM are a characteristic finding as is infiltration of the kidney with lymphoid cells. No characteristic lesion of the kidney has been described in the heavy-chain diseases. Mixed cryoglobulinemia associated with an IgM paraprotein can produce glomerulonephritis that is due to the deposition in the glomeruli of an immune complex consisting of IgG, IgM, and complement.

Animals↗
PubMed1992

Expression of the interleukin-2 receptor on human fibroblasts and its biological significance.

In this study, we have investigated the expression of the alpha and beta chains of the IL-2 receptor (IL-2R alpha, IL-2R beta) both at the membrane and at transcriptional levels during the lifespan of human embryonic fibroblasts. Here we show that the mAbs IOT14 and MIK beta 1 directed against the IL-2 binding sites of the IL-2R alpha and IL-2R beta respectively, stain human embryonic fibroblasts early in their life span. Data from [125I]rIL2 cross-linking experiments show the simultaneous expression of two IL-2 binding peptides of 70 and 55 kDa respectively on embryonic young fibroblasts as on lymphoid activated cells. The p55 and the p70 IL-2 binding peptides are shown to be specific for the IL-2R alpha and to the IL-2R beta by the finding that these bands are abolished by excess amounts of cold IL-2 and mAbs directed against the IL-2 binding sites of the alpha and beta chains. Scatchard analysis after [125I]IL-2 labelling shows the presence of both high affinity (150 sites with a Kd of 147 pM) and low affinity (1100 sites with a Kd of 4 nM) IL-2 binding sites. Northern blot and dot blot analysis show the presence of specific transcripts for the IL-2R alpha and IL-2R beta genes in early passaged fibroblasts. By contrast, in senescent cultures, only the IL-2R beta transcript were detected. Finally, IL-2 at low concentrations (36 pM) down modulates the level of the intercellular adhesion molecule ICAM-1 in young but not in senescent cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Adhesion Molecules↗
PubMed1997

Conformation of P22 tailspike folding and aggregation intermediates probed by monoclonal antibodies.

The partitioning of partially folded polypeptide chains between correctly folded native states and off-pathway inclusion bodies is a critical reaction in biotechnology. Multimeric partially folded intermediates, representing early stages of the aggregation pathway for the P22 tailspike protein, have been trapped in the cold and isolated by nondenaturing polyacrylamide gel electrophoresis (PAGE) (speed MA, Wang DIC, King J. 1995. Protein Sci 4:900-908). Monoclonal antibodies against tailspike chains discriminate between folding intermediates and native states (Friguet B, Djavadi-Ohaniance L, King J, Goldberg ME. 1994. J Biol Chem 269:15945-15949). Here we describe a nondenaturing Western blot procedure to probe the conformation of productive folding intermediates and off-pathway aggregation intermediates. The aggregation intermediates displayed epitopes in common with productive folding intermediates but were not recognized by antibodies against native epitopes. The nonnative epitope on the folding and aggregation intermediates was located on the partially folded N-terminus, indicating that the N-terminus remained accessible and nonnative in the aggregated state. Antibodies against native epitopes blocked folding, but the monoclonal directed against the N-terminal epitope did not, indicating that the conformation of the N-terminus is not a key determinant of the productive folding and chain association pathway.

Antibodies, Monoclonal↗
PubMed1994

Raynaud's phenomenon of fingers and toes among vibration-exposed patients.

Eleven patients with Raynaud's phenomenon of the toes as well as the fingers were encountered among about 1,000 vibration-exposed patients. They consisted composed of four chain-saw operators, five rock drillers, a stone quarrier and a welder in a shipyard. All the cases were examined carefully for differential diagnosis, but there were no particular abnormalities in hematological, immunological and homodynamic examinations. The rock drillers, quarrier and welder had direct vibration exposure of the foot, which was considered to be responsible for their Raynaud's phenomenon of the toe. Four chain-saw operators, who had been little exposed to vibration of the foot directly, were examined further on skin temperature of fingers and toes every three hours except at night and in a 30-min cold provocation test at 5 degrees C. The skin temperature of both their fingers and toes was lower than in age-matched healthy controls. The chain-saw operators started to work in the 1960's and early in the 1970's, when the chain saw vibration level was high. It is, hence, considered that they were exposed to strong vibration of the hand from chain saws, and then suffered severe Raynaud's phenomenon of both fingers and toes.

Aged↗
PubMed1988

Correlation between vibration-induced white finger and symptoms of upper and lower extremities in vibration syndrome.

The correlation was investigated between the frequency of attacks of vibration-induced white finger (VWF) and numbness or coldness of the fingers and legs in patients with vibration syndrome. Some 1687 patients with vibration syndrome were examined and of these 342 chain-saw operators and 277 rock-drill operators had no disease other than vibration syndrome. Then subjects were matched by age and period of treatment within three years. In the last analysis, 20 in the VWF "almost everyday" group or in the "never" group, and 40 in the "occasionally" group were selected from the chain-saw operators, and from the rock-drill operators 32 in the VWF "everyday" or the "never" group and 64 in the "occasionally" group. The present study showed that, with the frequency of VWF attacks, patients had a higher prevalence of coldness not only in the fingers but also in the legs. These findings suggest a correlation between the severity of circulatory disturbances of the upper extremities and that of the lower ones in patients with vibration syndrome. Further studies on circulatory disturbances in the leg are required.

Fingers↗
PubMed1995

Two genes that encode ribosomal-protein S6 kinase homologs are induced by cold or salinity stress in Arabidopsis thaliana.

We have isolated two closely related cDNA clones (cATPK19 and cATPK6) with homology to protein-serine/threonine kinases from Arabidopsis thaliana using the polymerase chain reaction (PCR). The deduced amino acid sequences of the ATPK19 and ATPK6 contain all 11 conserved regions of the catalytic domain of protein kinases, and have homology to p70 ribosomal S6 kinases (52%). ATPK19 and ATPK6 have putative PEST regions in their N- and C-terminal regions, and these regions also contain putative phosphorylation sites that are recognized by casein kinases or proline-directed protein kinases such as cdc2, MAP kinase, and p54 MAP-2 kinase (SAPK). The transcription levels of the ATPK19 and ATPK6 genes rapidly and markedly increased when plants were subjected to cold or high-salt stresses. These observations suggest that ATPK19 and ATPK6 may function in the adaptation of plant cells to cold or high-salt conditions, providing an understanding of the role of protein phosphorylation in plant responses to environmental stresses.

Adaptation, Physiological↗
PubMed1981

Photosynthetic apparatus of chilling-sensitive plants. IX. The involvement of alpha-tocopherol in the electron transport chain and the anti-oxidizing system in chloroplasts of tomato leaves.

1. The role of tocopherols in tomato chloroplasts from fresh, cold and dark-stored as well as stored and illuminated leaves was studied. 2. The cold and dark storage of leaves results in a loss of chloroplast alpha- and gamma-tocopherols of about 30-40% accompanied by an increase in chloroplast delta-tocopherol of about 40%. On illumination of stored leaves, an elevation of alpha- and gamma-tocopherol level to about 110 and 95% of the control, respectively, occurs, whilst delta-tocopherol content is not affected. 3. Experiments performed with 2,2-diphenyl-1-picrylhydrazyl-treated chloroplasts show that only about 70% of total alpha-tocopherol is functionally active in the electron transport of Photosystem II between the diphenylcarbazide (DPC) donation site and the inhibition site of DBMIB. 4. A small amount of alpha-tocopherol quinone (about 10% of alpha-tocopherol content) is found in chloroplasts from fresh, fresh and illuminated as well as cold and dark-stored tomato leaves, whereas the illumination of the latter increases the chloroplast alpha-tocopherol quinone content 3-fold. Moreover, following the illumination of chloroplasts from cold and dark-stored as well as stored and illuminated leaves, the oxidation of exogenous alpha-tocopherol to alpha-tocopherol quinone is 2-fold faster then in chloroplasts from fresh leaves. 5. The primary product ('alpha-tocopheroxide') formed during the alpha-tocopherol oxidation by illuminated chloroplasts was identified as 8a-hydroxy-alpha-tocopheron. 6. Exogenous alpha-tocopherol inhibits the lipid photoperoxidation by about 40-50% in chloroplasts from all three kinds of tomato leaf. 7. The results seem to suggest that chloroplast alpha-tocopherol is involved in both electron transport of PS II and antioxidizing system of chloroplasts.

2,6-Dichloroindophenol↗
PubMed2001

Cholesterol depletion induces large scale domain segregation in living cell membranes.

Local inhomogeneities in lipid composition play a crucial role in regulation of signal transduction and membrane traffic. Nevertheless, most evidence for microdomains in cells remains indirect, and the nature of membrane inhomogeneities has been difficult to characterize. We used lipid analogs and lipid-anchored proteins with varying fluidity preferences to examine the effect of modulating cellular cholesterol on domain formation. We show that lowering cholesterol levels induces formation of visible micrometer-scale domains in the plasma membrane of several mammalian cell types with complementary distributions of fluorescent lipid analogs with preferences for fluid or ordered domains. A uniform distribution is restored by cholesterol repletion. Unexpectedly, cholesterol depletion does not visibly alter the distribution of a crosslinked or uncrosslinked glycosylphosphatidylinositol-anchored protein (the folate receptor). We also examined the effect of varying cholesterol content on the cold Triton X-100 solubility of several membrane constituents. Although a cholesterol analog, dehydroergosterol, and a glycosylphosphatidylinositol-anchored protein are largely retained after extraction, a lipid analog with saturated 16-carbon acyl chains is largely removed when the cellular cholesterol level is lowered. This result indicates that after cholesterol depletion molecules in the more ordered domains can be extracted differentially by cold nonionic detergents.

Animals↗
PubMed1987

Atypical glycosylation of an IgG monoclonal cryoimmunoglobulin.

The NH2-terminal amino acid sequence of the heavy chain of the IgG monoclonal cryoimmunoglobulin Ger was determined. Evidence for the glycosylation of the first heavy chain hypervariable region of this protein was found. The inability of the deglycosylated Fab fragment of Ger to inhibit cryoprecipitation provides direct evidence that the presence of an additional sialic acid residue in a heavy chain's first hypervariable region can account for the cryo properties of this protein. This is the first convincing description of a molecular defect that explains the atypical low temperature solubility of a monoclonal cryoimmunoglobulin.

Amino Acid Sequence↗
PubMed2002

Level of galactosylation determines cryoglobulin activity of murine IgG3 monoclonal rheumatoid factor.

Autoantibodies of the cryoprecipitating IgG3 isotype have been shown to play a significant role in the development of murine lupus-like autoimmune syndrome. At present, the structural basis of IgG3 cryoprecipitation and its role in autoantibody pathogenicity remain to be defined. Using molecular variants of an IgG3 monoclonal rheumatoid factor, 6-19, derived from an autoimmune MRL-Fas(lpr) mouse, we have investigated the implication of charged residues in the heavy-chain variable (VH) region, potential CH3-linked oligosaccharides, and galactosylation of CH2-linked oligosaccharides in its cryoglobulin activity. The cryoglobulin activity of the IgG3 6-19 mutant bearing more negatively charged residues at VH 6 and 23 was found to be reduced but still highly significant, whereas that of the mutant lacking a potential CH3 glycosylation site remained unchanged. In marked contrast, IgG3 6-19 variants obtained from 6-19 heavy-chain transgenic mice displayed barely detectable cryoglobulin activity associated with an increased level of galactosylation in the CH2 oligosaccharide side chains. Thus, our data strongly suggest that the cryoglobulin activity of IgG3 6-19 autoantibody is critically determined by levels of galactosylation in the CH2 oligosaccharide side chains, whereas VH residues play a secondary role in 6-19 IgG3 cryoglobulin activity.

Animals↗