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PubMed2002

Photoperiodic regulation of the phospholipid molecular species composition in thoracic muscles and fat body of Pyrrhocoris apterus (Heteroptera) via an endocrine gland, corpus allatum.

In the conventional view, the winter adaptation of membrane lipids is induced by temperature decrease. We propose that winter remodelling of membranes in Pyrrhocoris apterus is triggered by short-day photoperiod before the temperature decrease and changes caused by cold temperature represent the later phase of adaptation. The induction of diapause by short-day photoperiod results in an accumulation of phosphatidylethanolamine (PE) molecular species with C(16:0)/C(18:2) acyl chains esterified to sn-1/sn-2 positions of glycerol at the expense of C(18:0)/C(18:2). Proportions of C(16:0)/C(18:2)-PE are enhanced in short-day compared to long-day insects in both thoracic muscles (TM, 15.0 vs. 8.2%) and fat bodies (FB, 24.9 vs. 13.6 %). Proportions of C(16:0)/C(18:2)-PE are further enhanced during cold acclimation (to 26.5% in TM, 33.6 % in FB) at the expense of a more saturated species, C(18:0)/C(18:1)-PE. These changes are less prominent in phosphatidylcholines (PC). The effect of photoperiod seems to be mediated via the corpus allatum. Long-day non-diapause females deprived of their corpus allatum have the phospholipid molecular species profile similar to that found in short-day diapausing females. While the acyl chain remodelling is regulated by both photoperiod and temperature, the head group composition is regulated by temperature only. Similar to most other organisms, the level of PE is higher (50.3 vs. 43.5% in TM, 44.3 vs. 37.8% in FB) and that of PC is lower (35.9 vs. 40.2% in TM, 41.6 vs. 46.1 % in FB) at cold temperatures (</=1 degrees C) compared to warm temperatures (>/=16 degrees C). In contrast to a general rule, the PE is less unsaturated than PC. In both TM and FB, proportions of unsaturated/unsaturated molecular species are consistently high in PC (56.3-67.5% in TM, 59.2-66.6% in FB), while they are consistently low in PE (19.1-26.7% in TM, 12.1-15.1% in FB). An adaptive significance of changes in the phospholipid composition for the low temperature and/or dehydration stress is discussed in relation to known physical properties of phospholipids.

Journal Article↗

PubMed2006

Facial cold-induced vasodilation and skin temperature during exposure to cold wind.

One purpose of this study was to characterize the facial skin temperature and cold-induced vasodilation (CIVD) response of 12 subjects (six males and six females) during exposure to cold wind (i.e., -10 to 10 degrees C; 2, 5, and 8 m/s wind speed). This study found that at each wind speed, facial skin temperature decreased as ambient temperature decreased. The percentage of subjects showing facial CIVD decreased significantly at an ambient temperature above -10 degrees C. A similar CIVD percentage was observed between 0 degrees C dry and 10 degrees C wet (face sprayed with fine water mist) at each wind speed. No CIVDs were observed during the 10 degrees C dry condition at any wind speed. The incidence of CIVD response was more uniform across facial sites when there was a greater cold stress (i.e., -10 degrees C and 8 m/s wind). Another objective of the study was to examine the effect of the thermal state of the body (as reflected by core temperature) on the facial skin temperature response during rest and exercise. This study found that nose skin temperature was significantly higher in exercising subjects with an elevated core temperature even though there was no significant difference in face skin temperature between the two conditions. Therefore, this finding suggests that acral regions of the face, such as the nose, are more sensitive to changes in the thermal state of the body, and hence will stay warmer relative to other parts of the face during exercise in the cold.

Adult↗

PubMedDate not supplied

Bottled water: how safe is it?

Sales of bottled water have increased dramatically in recent years, with worldwide sales of more than dollars 35 billion, largely because of the public perception of purity and safety and public concern about the quality of tap water. Presently, there are no Food and Drug Administration (Washington, D.C.) recommendations regarding temperature and duration of storage for bottled water once it is opened and used. The objectives of this study were to examine the effects of time and storage temperature on bacterial growth and characterize the types of microorganisms contaminating bottled water after drinking once from the bottle. Bottled and tap water were tested using standard microbiology culture techniques. The bacterial count in bottled water increased dramatically, from less than 1 colony per milliliter (col/mL) to 38,000 col/mL over 48 hours of storage at 37 degrees C. Bacterial growth was markedly reduced at cold temperatures (refrigeration) compared with room temperature, with 50% fewer bacterial colonies in 24 hours and 84% fewer colonies in 48 hours. Interestingly, tap water resulted in only minimal growth, especially at cold temperatures (< 100 col/mL at 48 hours). These findings may be useful to increase public awareness and development of guidelines on storage temperature and expiration time for bottled water once it is opened and used.

Bacteria↗

PubMed1986

Sterol manipulation that modulates the alteration in membrane fluidity of Tetrahymena pyriformis during temperature acclimation.

Our previous results [Umeki and Nozawa (1983) Biochem. Biophys. Res. Commun. 113, 96-101] suggested that ergosterol-replaced Tetrahymena cells (ergosterol-cells) accomplish an adaptive modification of fatty-acid composition by a preferential increase in palmitoyl-CoA desaturase activity, which is principally due to the increased content of the terminal component (cyanide-sensitive factor) of the desaturase system. The present study was designed to obtain information as to how the membrane fluidity of ergosterol-cells is changed during cold temperature acclimation. The order parameter (S) of liposomes prepared from ergosterol-cell lipids was reduced more rapidly after a temperature shift-down than that of control liposomes prepared from native cells containing tetrahymanol. These results indicate that, unlike native cells containing tetrahymanol, ergosterol-cells strive to accomplish cold temperature acclimation by undergoing a great modification of membrane fluidity because of the altered microsomal desaturase activity.

Acclimatization↗

PubMed1997

The wheat protein kinase gene, TaPK3, of the PKABA1 subfamily is differentially regulated in greening wheat seedlings.

We have identified a new wheat PKABA1-like protein kinase gene, TaPK3, that is expressed in greening wheat seedlings. TaPK3 has high sequence homology (97% similarity with some sequence diversity at the 3' end) to the wheat PKABA1 protein kinase mRNA, which is upregulated by cold-temperature treatment, dehydration and abscisic acid (ABA). Use of a TaPK3 gene-specific probe has revealed that TaPK3 is differentially expressed with respect to PKABA1. TaPK3 mRNA accumulates in greening shoot tissue of wheat, but is not affected by dehydration, cold-temperature treatment or ABA. Based on sequence and expression differences, we conclude that expression of the PKABA1-like protein kinases is not limited to stress responses.

Amino Acid Sequence↗

PubMed2005

Effect of environmental temperature on shock absorption properties of running shoes.

OBJECTIVE: To determine the effect of temperature changes on the shock attenuation of 4 running shoe shock absorption systems. DESIGN: Prospective. SETTING: Motion analysis laboratory. INTERVENTIONS: The shock attenuation of 4 different running shoes representing common shock absorption systems (Nike Air Triax, Asics Gel Nimbus IV, Adidas a3 cushioning, Adidas Supernova cushion) was measured at ambient temperatures of -20 degrees C, -10 degrees C, 0 degrees C, +10 degrees C, +20 degrees C, +30 degrees C, +40 degrees C, and +50 degrees C. Repeated-measures analysis of variance was used to determine differences between shoes. OUTCOME MEASURES: Shock attenuation as indicated by peak deceleration (g) measured by a mechanical impactor following ASTM Standard F1614-99. RESULTS: Shock attenuation decreased significantly with reduced temperature for each shoe tested. The Adidas a3 shoe exhibited significantly higher peak decelerations (lower shock attenuation) at cold temperatures compared with the other shoes. CONCLUSIONS: Cold ambient temperatures significantly reduce the shock attenuation of commonly used running shoes. These findings have important clinical implications for individuals training in extreme weather environments, particularly those with a history of lower limb overuse injuries.

Athletic Injuries↗

PubMed1984

Manual performance in the cold with gloves and bare hands.

Previous research aimed at quantifying and reducing the decrements encountered in performing manual tasks in cold weather has not described the relationships between task characteristics and cold-induced impairments. The amount of decrement and, often times, the optimal means for reducing the decrement, appear to be task-specific. The research reported here is one in a series of studies formulated to explore those relationships. The strategy is to use tasks from the battery developed by Fleishman (1967) to measure the factorially 'pure' abilities needed to perform all manual tasks. 24 U.S. Marines performed this battery of nine tasks across a range of cold temperatures. To determine if the decrement due to wearing gloves might be less than the decrement due to cold hands as the air temperature decreased, performance on the battery of tasks was measured with and without gloves. Only three of the tasks (abilities) were affected by cold temperatures, and the amount of decrement increased as the air temperature decreased. Three tasks deteriorated due to wearing of gloves, two of those affected by cold and one other. Temperature affected performance independently of the glove effect. Half of the subjects did not complete bare-handed testing at -18 degrees C (approximately 20 min.), indicating this is the lower end of the temperature range in which bare-handed performance for more than a few minutes is practical.

Adolescent↗

PubMed2001

RNA anchoring in the vegetal cortex of the Xenopus oocyte.

The body plan of the embryo is established by a polarized source of developmental information in the oocyte. The Xenopus laevis oocyte creates polarity by anchoring mRNAs in the vegetal cortex, including Vg1 and Xwnt-11, which might function in body plan specification, and Xcat-2, which might function in germ cell development. To identify components of the RNA anchoring mechanism, we used the manually isolated vegetal cortex (IVC) to assay loss or change in spatial arrangement of mRNAs caused by disruption of cortical elements. The role of cytoskeleton in mRNA anchoring was tested by treating oocytes with inhibitors that selectively disrupted actin microfilaments and cytokeratin filaments. Treatment of oocytes with cytochalasin B caused clumping of Vg1 and Xwnt-11 as revealed by in situ hybridization of the IVC, but did not cause their release, as confirmed by RT-PCR analysis. These mRNA clumps did not match the distribution of actin microfilament clumps, but were distributed similarly to the remnant cytokeratin filaments. Treatment of oocytes with monoclonal anti-cytokeratin antibody C11 released these mRNAs from the cortex. C11 altered the texture of the cytokeratin network, but did not affect the actin meshwork. These results show that Vg1 and Xwnt-11 are retained by a cytokeratin filament-dependent mechanism, and that organization of the cytokeratin network depend on an intact actin meshwork. Colcemid did not disrupt Vg1 and Xwnt-11 retention in the IVC, so anchoring of these mRNAs are independent of microtubules. Membrane disruption in the IVC by Triton X-100 decreased Vg1 and Xwnt-11. Loss of these mRNAs was due mainly to ribonuclease activity released from membrane components. However, when ribonuclease activity was suppressed under cold temperature, a higher amount of Vg1 and Xwnt-11 was recovered in the supernatant. This result suggested that a fraction of these mRNAs required membranes to be retained in the cortex. By contrast, Xcat-2 mRNA was neither released nor degraded following treatments with cytochalasin B, C11, colcemid and Triton X-100 under cold temperature, so no cortical element could be implicated in its anchoring.

Actins↗

PubMed2006

DNA degradation in nuclei of muscle cells followed by ischemic injury in a rabbit amputation model.

This study evaluated DNA degradation in nuclei of muscle cells during ischemia in a rabbit limb amputation model. Seven New Zealand rabbits were used. The left rear limb of the animal was amputated. The quadriceps femoris muscle was biopsied, as well as the rabbit carotid arteries. Half of the tissue samples were preserved at a cold temperature (2-4 degrees C), and the other half were kept at room temperature (25 degrees C, global ischemia). Immediately and 4, 8, 12, 16, and 24 h after amputation, muscle tissue samples were stained with the Feulgen reaction and analyzed by an image-analysis system to detect DNA contents in muscle cell nuclei. Samples from carotid arteries were examined with a transmission electron microscope. The results showed that the DNA content in muscle cell nuclei was slightly decreased at 4 and 8 h of global ischemia. At 12 h after global ischemia, the DNA content was found to be significantly decreased (80.03% of baseline). The DNA content dropped to 53.93% of baseline at 16 h of global ischemia. However, in the muscle that was preserved at cold temperature, the DNA contents were only slightly changed along with the ischemia time at 24 h. The DNA changes were confirmed by transmission electron microscopic observations. The present findings could provide evidence for the study of revascularization of ischemic muscle.

Amputation, Surgical↗

PubMed1999

Sensation recovery on innervated radial forearm flap for hemiglossectomy reconstruction by using different recipient nerves.

The objectives of this study were (1) to determine the extent of sensory recovery on hemitongues reconstructed with innervated radial forearm flaps and (2) to assess the influence of various clinical and surgical factors over the return of sensation, including the use of different recipient nerves for neurorrhaphy. Twenty-eight patients with tongue cancer who underwent hemiglossectomy and primary reconstruction with innervated radial forearm flaps over a 3-year period were studied. Mean postoperative follow-up was 18.2 months (range 6 to 32 months). Sensory recovery was assessed in a blind manner by two examiners that used (1) static two-point discrimination, (2) light touch sensation, (3) pain perception, and (4) hot and cold temperature perception. Different surfaces were assessed with each method on the reconstructed hemitongue and on the intact contralateral hemitongue (used as control). The following factors and their relationship with flap sensory recovery were analyzed: age, smoking history, size of the reconstructed defect, administration of postoperative radiation therapy, recipient nerve, and neurorrhaphy technique. Comparative statistical analysis (p < 0.05) between both hemitongues was performed using paired t test followed by Bonferroni correction for static two-point discrimination and light touch sensation. Fisher exact test analysis was used for pinprick and hot and cold temperature perception. The control side was ignored in analyzing the effects of the risk factors. The tip, dorsal aspect, ventral surface, and floor of mouth on the reconstructed hemitongue had comparable static two-point discrimination when compared with the intact hemitongue. Light touch sensation was also similar in the tip and dorsal aspect of both hemitongues; however, a statistically significant difference (p < 0.05) was observed on the ventral surface and floor of mouth of the reconstructed hemitongues. Likewise, pain perception was significantly decreased in the floor of the mouth, compared with other surfaces. No clearly dependent association was established between return of flap sensation and age, tobacco use, and size of the reconstructed defect. Light touch sensation, pain, and temperature perception were significantly decreased when the patients had received postoperative radiation therapy. In addition, all four sensory tests were significantly diminished (p < 0.05) when the recipient nerve used for neurorrhaphy was a nerve other than the lingual or the inferior alveolar nerve, and also when an end-to-side nerve repair was used. Sensation recovery of the innervated radial forearm flap after hemitongue reconstruction approaches normal compared with the contralateral intact hemitongue. Lower return of sensation may be anticipated in patients who receive postoperative radiotherapy. Good recovery of sensation is predictable when either the lingual or inferior alveolar nerve is used for neurorrhaphy, in contrast to using other recipient nerves.

Adult↗

PubMed1983

Determination of the rate of rRNA synthesis in Xenopus laevis triploid embryos produced by low-temperature treatment.

Triploid embryos of Xenopus laevis were obtained by cold-temperature shocking of the fertilized eggs, and the rate of the ribosomal RNA (rRNA) synthesis was determined for comparison with that in diploid embryos. For this purpose, both triploid and diploid embryos were dissociated into cells at the neurula stage, and then labeled with (3H)uridine for varying lengths of time. The rate of rRNA synthesis, as estimated after determination of (3H)UTP specific radioactivity and the total label incorporation into the purified rRNA, was about 0.1 pg/cell/hr for both diploid and triploid embryo cells. Nuclei of triploid embryo cells contained three nucleoli of apparently similar sizes--an indication of the functioning of all the three rRNA gene clusters to a more or less similar extent. Also, rates of synthesis of 4S RNA and 5S RNA were determined: Both rates did not change appreciably between triploid and diploid embryo cells. Based on these results, it appears that transcription of these redundant genes occurs at a constant rate on a per cell basis irrespective of the presence of 1.5 times as many genes as the control.

Animals↗

PubMed1995

[Sensitivity of the anal canal: study techniques and results in normal subjects].

AIM: To describe a technique for the study of the anal canal sensitivity to electric and thermal stimulation, and to investigate it prospectively in normal subjects. EXPERIMENTAL DESIGN: Mucosal electrosensitivity and thermal sensation of the anal canal is correlated with motor parameters: perineometry, manometry and electrophysiology. PATIENTS: 41 control subjects (20M & 21F) with normal anorectal anatomophysiology. RESULTS: In the middle anal canal minimum electrosensibility thresholds were present, and they were similar to the thermal profile. A significant impairment in electrosensitivity was observed as a function of age, but no differences between the sexes were found. Lower thresholds were obtained than cold temperatures (p < 0.001). Both tests of sensitivity correlated with pudendal motor parameters. The maximal thermal difference in the anal canal was 0.28 degree C, while the minimal detectable temperature change was 0.46 +/- 0.1 degrees C. CONCLUSIONS: The sensitivity of the anal canal is greatest in the zone of the anal valves and better in response to hot than cold stimulus. As the minimum detectable temperature change has been greater than the difference of temperature between the low and high anal canal, we suggest that discrimination is not possible on the basis of thermal differences.

Adolescent↗

PubMed2007

Orphan nuclear receptor estrogen-related receptor alpha is essential for adaptive thermogenesis.

Survival of organisms requires the ability to adapt to changes in the environment. Adaptation of oxidative metabolism is essential for meeting increased energy demands in response to stressors, such as exposure to cold temperatures or increased physical activity. Adaptive changes in metabolism are often achieved at the level of gene expression, and nuclear receptors have prevalent roles in mediating such responses. Estrogen-related receptor alpha (ERRalpha) was the first orphan nuclear receptor to be identified, and yet its physiologic function remains unknown. Here, we show that mice lacking ERRalpha are unable to maintain body temperature when exposed to cold. Surprisingly, the inability to adapt to cold is not due to defects in the acute transcriptional induction of genes important for thermogenesis. Rather, we show that ERRalpha is needed for the high levels of mitochondrial biogenesis and oxidative capacity characteristic of brown adipose tissue (BAT), and thus for providing the energy necessary for thermogenesis. ERRalpha fulfills this role by acting directly at genes important for mitochondrial function, parallel to other factors controlling mitochondrial gene expression, such as NRF1 and NRF2/GABPA. Our findings demonstrate that ERRalpha is a key regulator of mitochondrial biogenesis and oxidative metabolism, and essential for adaptive thermogenesis.

Adaptation, Physiological↗

PubMed2000

A comparison of myocardial beta-adrenoreceptor density and ligand binding affinity among selected teleost fishes.

This study quantified the cell surface beta-adrenoreceptor density and ligand binding affinity in the ventricular tissue of seven teleost species; skipjack tuna (Katsowonus pelamis), yellowfin tuna (Thunnus albacares), Pacific mackerel (Scomber japonicus), mahimahi (dolphin fish; Coryphaena hippurus), sockeye salmon (Oncorhynchus nerka), rainbow trout (Oncorhynchus mykiss) and an Antarctic nototheniid (Trematomus bernacchii). Beta-Adrenoreceptor density varied by almost fourfold among these species, being highest for the athletic fish: sockeye salmon among the salmonids and skipjack tuna among the scombrids. Beta-Adrenoreceptor density was lowest for the Antarctic icefish. Beta-Adrenoreceptor binding affinity varied by almost threefold. We conclude that there is a significant species-specific variability in myocardial beta-adrenoreceptor density and binding affinity and these interspecific differences cannot be attributed to temperature even though intraspecifically cold temperature can stimulate an increase in myocardial beta-adrenoreceptor density. Instead, we suggest that interspecifically myocardial beta-adrenoreceptor density is highest in fish that inhabit tropical water.

Animals↗

PubMed1980