升温诱发高血压大鼠脑梗塞发病的神经内分泌机制

目的：研究气温骤升导致高血压大鼠发生脑梗塞的神经内分泌机制。方法：采用易卒中型肾血管性高血压（RHRSP）模型,放置于人工模拟气温骤升的高温环境中诱发脑梗塞,检测高温刺激前后大鼠ACTH、CORT、TSH、T3、T4的变化。结果：突然升温使生理组大鼠ACTH和CORT水平表现升高的趋势。模型组高血压大鼠CORT、TSH、T3、T4水平在升温中均呈现升高趋势,但是ACTH水平却明显降低（P〈0.05）。升温后发生脑梗塞大鼠的ACTH和T4水平与升温前比明显下降（P〈0.01）,而TSH水平明显高于升温前水平（P〈0.05）,T3水平不变。结论：高血压机体应激反应系统紊乱,甲状腺刺激素和肾上腺皮质激素的异常波动,是突然高温促发高血压机体脑梗塞发病的重要神经内分泌机制。     

Influence of temperature on activity of the isolated whole bladder preparation of neonatal and adult rats

The temperature sensitivity of in vitro whole bladder preparations from neonatal and adult rats with or without chronic partial urethral obstruction was investigated. After the bladder was filled to a volume eliciting isovolumetric contractions, temperature was changed between 19 and 38 degrees C. In all preparations, higher temperatures were associated with higher frequencies of spontaneous intravesical pressure waves (IVPW). In 1- to 2-wk-old neonates, IVPW amplitude increased as the temperature increased; however, in older neonates and normal adults, the opposite occurred. The transition period was at 3 wk of age when bladder volume also markedly increased. At this age as well as in adult rats with outlet obstruction, changing temperature had little influence on the amplitude of IVPW. Thus obstructed outlet bladders and 3-wk-old bladders had similar properties. It is concluded that the properties of bladder muscle are changed during postnatal maturation and that in 3-wk-old rats, when brain control of voiding is emerging, micturition is abnormal, leading to obstructive changes in bladder muscle.     

Changes in lipid peroxidation, superoxide dismutase activity, ascorbic acid and phospholipid content in liver of freshwater catfish Heteropneustes fossilis exposed to elevated temperature

1. 1. Lipid peroxidation, superoxide dismutase (SOD) activity, ascorbic acid (AsA) and individual phospholipid contents in liver of fresh water cat fish Heteropneustes fossilis were measured after exposure to different temperatures (25, 27, 32, 37°C) at various times (1–4 h).

2. 2. Lipid peroxidation and superoxide dismutase activity were significantly increased with increases in temperature at various times.

3. 3. Ascorbic acid content was depleted when temperature was increased.

4. 4. After temperature exposure, phosphatidyl inositol was increased while phosphatidyl choline, phosphatidyl serine and phosphatidyl ethanolamine were depleted. Phosphatidic acid level did not change.

5. 5. The findings indicated an increased oxidative stress in liver following increases in temperature at various times. Concurrent with the increase in lipid peroxidation, superoxide dismutase activity and ascorbic acid from the liver of fish varied. It is suggested that depletion of major individual phospholipids following temperature exposure could be due to superoxide created oxidative stress in the liver.

     

西北干旱区不同海拔高度地区气温变化对春小麦生长的影响

基于1981—2006年西北干旱区高海拔地（民乐站）和低海拔地（张掖站）农业气象观测站的观测资料,对民乐站和张掖站的气温变化及其对春小麦生长发育和产量的影响进行了研究.结果表明：研究期间,民乐站、张掖站的气温均呈增加趋势,且高海拔地区的增温幅度大于低海拔地区;民乐站春小麦对气温变暖的响〖JP2〗应表现为生育期缩短、产量增加,张掖站春小麦对气温变暖的响应表现为生育期缩短、产量下降;春小麦生育期内日均气温每升高1 ℃,民乐站和张掖站春小麦生育期分别缩短8.3 d和3.8 d.民乐站春小麦生育期内最高气温低于30.4 ℃时,春小麦生育期和产量均小幅增加,当超过30.4 ℃时,春小麦生育期缩短、产量下降.     

The effects of temperature- and oxygen-acclimation on phospholipids of goldfish (Carassius auratus L.) brain microsomes

Brain microsome phospholipids and their acyl groups, from temperature and oxygen acclimated goldfish, were investigated. At the lower acclimation temperature (5C) the proportion of ethanolamine- to choline-glycerophosphatides (GPE/GPC) was increased, and the proportion of phosphatidal ethanolamine value decreased. A rise in the n-6/n-3 fatty acyl group also occurred in cold acclimation. Irrespective of acclimation temperature, 25 degrees C or 5 degrees C, a partial replacement of GPC by GPE occurred when the concentration of oxygen was increased; conversely the GPE/GPC ratio decreased at the hypoxic level. The plasmalogen GPE content increased as the oxygen concentration was raised. A rise in the n-6/n-3 ratio, for ethanolamine glycerophosphatides and phosphatidyl choline, occurred when the oxygen concentration was increased (hypoxia to hyperoxia). It is concluded that the lipid alterations associated with thermal acclimation are, in part, attributable to the concomitant change in oxygen concentration.     

Structural perturbation of alphaB-crystallin by zinc and temperature related to its chaperone-like activity

alphaB-crystallin is a small heat shock protein that shows chaperone-like activity, as it protects the aggregation of denatured proteins. In this work, the possible relationships between structural characteristics and the biological activity of alphaB-crystallin were investigated on the native protein and on the protein undergoing the separate effects of metal ligation and temperature. The chaperone-like activity of alphaB-crystallin increased in the presence of zinc and when temperature was increased. By using fluorescent probes to monitor hydrophobic surfaces on alphaB-crystallin, it was found that exposed hydrophobic patches on the protein surface increased significantly both in the presence of zinc and when the temperature was raised from 25 to 37 degrees C. The zinc-induced increased exposure of lipophilic residues is in agreement with theoretical calculations performed on 3D-models of monomeric alphaB-crystallin, and may be significant to its increased biological activity.     

Survival of T3 Coliphage in Varied Extracellular Environments. I. Viability of the Coliphage During Storage and in Aerosols

The objective of this study was to determine the feasibility of using airborne T3 coliphage as a viral tracer in microbial aerosols. Although T3 coliphage was relatively stable when stored either at temperatures ranging from 21 to 37 C or in the frozen state at -20 C, there was a 2-log loss in infectivity when stored for 72 days at 4 C. Either agitation of stored coliphage suspensions held at 31 C or wide fluctuations in storage temperature produced an increased loss of infectivity. In the airborne state, freshly prepared coliphage and stored coliphage behaved similarly, with survival diminishing as the relative humidity (RH) was lowered. The greatest loss occurred during the first five min following aerosolization. The results showed that only under certain conditions of temperature and relative humidity can T3 coliphage be used as a satisfactory aerosol tracer.     

Effects of a 4 °C increase in temperature on partitioning of leaf area and dry mass, root respiration and carbohydrates

1. Plants of Bellis perennis, Dactylis glomerata and Poa annua were grown from seed in controlled-environment cabinets at either 16 or 20 °C; at the higher temperature all three species had increased total dry mass and leaf area when assessed on the basis of chronological time. On the basis of thermal time (summation of degree-days above 0 °C; days °C) temperature decreased the dry mass in P. annua.
2. Partitioning was assessed as a change in the allometric coefficients relating shoot and root dry mass, leaf and plant mass, leaf area and plant mass, and leaf area and leaf mass. Of the 12 relationships examined only three were affected by temperature: there was increased partitioning towards the shoot relative to the root in D. glomerata and increased partitioning towards leaf area rather than leaf mass in D. glomerata and B.perennis .
3. Root respiration was unaffected by temperature of growth in D. glomerata and P.annua but was lower in B. perennis grown at elevated temperature.
4. Root respiration acclimated to temperature in P. annua and B. perennis (i.e. when measured at the same temperature, respiration was higher in plants grown at 16 °C).
5. Root soluble carbohydrate concentration was unaffected by temperature of growth in any of the species. Feeding sucrose to the roots for a short period had no effect on the rate of respiration of B. perennis or D. glomerata but increased root respiration of P. annua .     

Thermotolerance of brown trout,Salmo trutta,gametes and embryos to increased water temperatures

The present study investigated the effect of increased water temperature on sperm motility when activated in water, on egg water hardening, on the fertilization process and on embryonic development in brown trout, Salmo trutta. Brown trout gametes had a broad temperature optimum ranging from 3 to 15°C. In this temperature range the processes of egg water hardening and fertilization were unaffected. Motility duration was also not affected. The percentages of initial sperm motility and swimming velocity were lower at 9–15°C than at 3–7°C, while the percentage of locally motile spermatozoa was higher. Exposure of brown trout embryos to ≥11°C resulted in reduced percentages of hatched larvae and in increased percentages of malformed larvae. More advanced ontogenetic stages (stages ≥9 according to Ballard [1973]) showed higher tolerance to increased temperature than did less advanced stages (stages <9) when the percentage of eyed stage embryos was used as the evaluation end point. However, when the percentages of hatched larvae and normal shaped larvae were used as evaluation end points, no differences in thermotolerance could be found between the different otogenetic stages.     

Cytochrome abnormalities and cyanide-resistant respiration in extranuclear mutants of Aspergillus nidulans.

The cytochrome spectra of two extranuclear mutants of Aspergillus nidulans and the double-mutant recombinant formed from them have been examined both at room temperature and at the temperature of liquid N2 and compared with those of the wild-type strain. The oligomycin-resistant, slow growing mutant contained an increased amount of cytochrome c without any loss of cytochromes b and a,a3. The cold-sensitive mutant, apparently normal when grown at 37 C, showed an increased amount of cytochrome c and a partial loss of cytochromes b and a,a3 when grown at 20 C. A combination of these effects was observed in the double-mutant recombinant. Cyanide-resistant respiration was present in both mutant strains and in the recombinant at much higher levels than in the wild-type strain. In the oligomycin-resistant mutant, this was usually present together with cyanide-sensitive respiration, whereas in the cold-sensitive mutant and recombinant grown at 20 C cyanide-resistant approached 100%. Inhibitor and growth yield studies indicated that the cyanide-resistant pathway was not used by the cold-sensitive mutant during growth at 20 C.     

Effects of temperature on sound production and auditory abilities in the Striped Raphael catfish Platydoras armatulus (Family Doradidae)

Background

Sound production and hearing sensitivity of ectothermic animals are affected by the ambient temperature. This is the first study investigating the influence of temperature on both sound production and on hearing abilities in a fish species, namely the neotropical Striped Raphael catfish Platydoras armatulus.

Methodology/Principal Findings

Doradid catfishes produce stridulation sounds by rubbing the pectoral spines in the shoulder girdle and drumming sounds by an elastic spring mechanism which vibrates the swimbladder. Eight fish were acclimated for at least three weeks to 22°, then to 30° and again to 22°C. Sounds were recorded in distress situations when fish were hand-held. The stridulation sounds became shorter at the higher temperature, whereas pulse number, maximum pulse period and sound pressure level did not change with temperature. The dominant frequency increased when the temperature was raised to 30°C and the minimum pulse period became longer when the temperature decreased again. The fundamental frequency of drumming sounds increased at the higher temperature. Using the auditory evoked potential (AEP) recording technique, the hearing thresholds were tested at six different frequencies from 0.1 to 4 kHz. The temporal resolution was determined by analyzing the minimum resolvable click period (0.3–5 ms). The hearing sensitivity was higher at the higher temperature and differences were more pronounced at higher frequencies. In general, latencies of AEPs in response to single clicks became shorter at the higher temperature, whereas temporal resolution in response to double-clicks did not change.

Conclusions/Significance

These data indicate that sound characteristics as well as hearing abilities are affected by temperatures in fishes. Constraints imposed on hearing sensitivity at different temperatures cannot be compensated even by longer acclimation periods. These changes in sound production and detection suggest that acoustic orientation and communication are affected by temperature changes in the neotropical catfish P. armatulus.     

Modulation of plasma biotin in the fowl (Gallus domesticus) by oestrogen and ambient temperature.

1. Exposure of laying hens to elevated ambient temperatures (30-40 degrees C) resulted in a significant increase in the biotin concentrations in plasma and egg yolk. 2. Exogenous oestrogen administration to immature pullets increased plasma biotin three-fold. The increase was six-fold when the birds were simultaneously exposed to an ambient temperature of 35 degrees C. 3. It is proposed that ambient temperature affects the balance between thyroid and ovarian hormones resulting in increased circulating levels of biotin and deposition of the vitamin in egg yolk.     

Global change‐type drought‐induced tree mortality: vapor pressure deficit is more important than temperature per se in causing decline in tree health

Drought‐induced tree mortality is occurring across all forested continents and is expected to increase worldwide during the coming century. Regional‐scale forest die‐off influences terrestrial albedo, carbon and water budgets, and land‐surface energy partitioning. Although increased temperatures during drought are widely identified as a critical contributor to exacerbated tree mortality associated with “global‐change‐type drought”, corresponding changes in vapor pressure deficit (D) have rarely been considered explicitly and have not been disaggregated from that of temperature per se. Here, we apply a detailed mechanistic soil–plant–atmosphere model to examine the impacts of drought, increased air temperature (+2°C or +5°C), and increased vapor pressure deficit (D; +1 kPa or +2.5 kPa), singly and in combination, on net primary productivity (NPP) and transpiration and forest responses, especially soil moisture content, leaf water potential, and stomatal conductance. We show that increased D exerts a larger detrimental effect on transpiration and NPP, than increased temperature alone, with or without the imposition of a 3‐month drought. Combined with drought, the effect of increased D on NPP was substantially larger than that of drought plus increased temperature. Thus, the number of days when NPP was zero across the 2‐year simulation was 13 or 14 days in the control and increased temperature scenarios, but increased to approximately 200 days when D was increased. Drought alone increased the number of days of zero NPP to 88, but drought plus increased temperature did not increase the number of days. In contrast, drought and increased D resulted in the number of days when NPP = 0 increasing to 235 (+1 kPa) or 304 days (+2.5 kPa). We conclude that correct identification of the causes of global change‐type mortality events requires explicit consideration of the influence of D as well as its interaction with drought and temperature.     

Limits to productivity of the alga Pleurochrysis carterae (Haptophyta) grown in outdoor raceway ponds

This study examined the effects of oxygen concentration, pond temperature and irradiance on productivity and CaCO(3) formation of the coccolith-forming alga, Pleurochrysis carterae CCMP647 grown in semi-continuous culture in outdoor raceway ponds. During the day the oxygen content of the pond increases markedly and P. carterae photosynthesis is inhibited by these high O(2) concentrations with the inhibition increasing with increasing temperature. The high irradiance outdoors presents less of a problem to photosynthesis and productivity as the algae can acclimate well to high irradiances over a period of several weeks. Pond depth also effects productivity and this effect varies with season. During autumn, productivities were highest at depths of 13 to 16 cm, and decreased when the depth was increased. During summer productivity was much lower at 13 cm pond depth and increased when the depth was increased to 16, 18 and 21 cm. Heating the ponds in the morning by approximately 3 to 5 degrees C improves productivity by 11%-21%, presumably because this allows the algae to photosynthesise faster in the conditions of low [O(2)] which occur in the early morning.     

Gibberellin, daylength and temperature effects on floral and vegetative development in white clover

The effects of gibberellin A₃ (GA₃) application on five white clover populations was assessed in both glasshouse and controlled environments. Daylength, temperature and GA₃ interactions were also examined. Gibberellin A₃ did not induce vegetative plants to flower when daylength and temperature requirements were not met. In flowering plants, GA₃ increased the number of reproductive buds per stolon and peduncle length, but did not affect other floral characters. Gibberellin A₃ depressed total stolon numbers, but increased the number of nodes per stolon, internode length, leaf area and petiole length.     

Ammonia Flux between Oilseed Rape Plants and the Atmosphere in Response to Changes in Leaf Temperature,Light Intensity,and Air Humidity (Interactions with Leaf Conductance and Apoplastic NH4+ and H+ Concentrations)

NH3 exchange between oilseed rape (Brassica napus) plants and the atmosphere was examined at realistic ambient NH3 levels under controlled environmental conditions. Different leaf conductances to NH3 diffusion were obtained by changing leaf temperature (10 to 40[deg]C), light intensity (0 to 600 [mu]mol m-2 s-1), and air humidity (20 to 80%), respectively. NH3 adsorption to the cuticle with subsequent NH3 transport through the epidermis had no significant effect on the uptake of atmospheric NH3, even at 80% relative air humidity. NH3 fluxes increased linearly with leaf conductance when light intensities were increased from 0 to 600 [mu]mol m-2 s-1. Increasing leaf temperatures from 10 to 35[deg]C caused an exponential increase in NH3 emission from plants exposed to low ambient NH3 concentrations, indicating that leaf conductance was not the only factor responding to the temperature increase. The exponential relationship between NH3 emission and temperature was closely matched by the temperature dependence of the mole fraction of gaseous NH3 above the leaf apoplast (NH3 compensation point), as calculated on the basis of NH4+ and H+ concentrations in the leaf apoplast at the different leaf temperatures. NH3 fumigation experiments showed that an increase in leaf temperature may cause a plant to switch from being a strong sink for atmospheric NH3 to being a significant NH3 source. In addition to leaf temperature, the size of the NH3 compensation point depended on plant N status and was related to plant ontogeny.     

铃期增温对棉花产量、品质的影响及其生理机制

以泗棉3号棉花品种为材料,于2010和2011年在南京农业大学牌楼试验站设置铃期(7月13日-8月24日)增温试验,模拟全球增温条件下棉花产量、品质的变化趋势及其生理机制.结果表明: 在铃期增温2～3 ℃(日均温31.1～35.2 ℃)条件下,植株总生物量下降约10%,单株皮棉及籽棉产量降低30%～40%.棉纤维品质变化显著,且不同纤维品质指标对增温的响应程度存在较大差异:马克隆值和断裂比强度显著升高,纤维长度下降,而整齐度指数和伸长率无显著变化.棉株光合能力、干物质累积能力和光合产物输出能力显著下降;可溶性氨基酸、可溶性糖、蔗糖含量及碳氮比均显著下降,而淀粉含量显著上升;增温条件下营养器官干物质分配比例增多,生殖器官干物质分配比例相对减少,经济系数随之降低.棉株下部果枝受增温影响较小,中、上及顶部果枝受增温影响较大.表明在增温2～3 ℃条件下,棉株大部分时间处于热胁迫状态,不仅光合能力下降,而且光合产物向“库”端的转运能力下降,最终导致其减产.     

短期物理应激对云芝菌丝体SOD活性的影响

选取高低温分别胁迫、协同胁迫以及超声波处理等方式研究了短期物理应激对云芝菌丝体超氧化物歧化酶（SOD）活性的影响。与未作胁迫处理的对照相比,在低温处理中,10℃较之15℃处理SOD活性整体水平有明显提高,10℃处理2h可使SOD活性提高36.2%,延长处理时间导致SOD活性下降;高温协迫中30℃处理效果优于40℃、50℃和60℃,30℃处理4h,SOD相对酶活可提高至26.8%,延长处理时间和提高处理温度均导致SOD活性下降。高低温协同作用L16(2×42)正交试验结果分析表明,30℃处理2h后10℃处理     

The action of urocortins on body temperature in rats

The actions of individual urocortins on colon temperature were studied in rats. Urocortin 1, urocortin 2 or urocortin 3 was injected into the lateral brain ventricle in conscious rats and the colon temperature was measured at different times following injection, for up to 6 h. In order to study the possible role of prostaglandins, the animals were treated with either a urocortin together with the pyrazolone derivative noraminophenazone to inhibit the action of cyclooxygenase in initiating hyperthermia, or with noraminophenazone 30 min following urocortin administration to act on existing hyperthermia. Noraminophenazone was administered intramuscularly in a dose of 50 mg/kg. Urocortin 1 caused a dose-related increase in colon temperature, maximal action being observed at a dose of 2 microg with the maximal increase in body temperature at 4 h. Noraminophenazone prevented the urocortin-induced increase in colon temperature and attenuated the already existing elevated body temperature. Somewhat similar action was observed with urocortin 2. However, following treatment with 0.5 or 1.0 microg urocortin 2, the action was already over at 2 h, whereas 2 microg increased the colon temperature steadily, with a maximum at 4 h. Noraminophenazone blocked or diminished the action of urocortin 2. Urocortin 3 in a dose of 1 microg was the most effective in increasing the colon temperature; the maximal effect was observed at 2 h. Noraminophenazone blocked the development of urocortin 3-induced hyperthermia, or attenuated it when the hyperthermia was already present. The results demonstrated that urocortin 1, 2 or 3 caused increases in body temperature when injected into the lateral brain ventricle, though the optimal dose and the duration of hyperthermia differed for the individual urocortins. The cyclooxygenase inhibitor blocked or diminished the action of these urocortins, indicating the involvement of prostaglandins in urocortin-induced hyperthermia.     

Evidence for altered polar and lateral auxin transport in the gravity persistent signal (gps) mutants of Arabidopsis

Plant shoots do not respond when they are reoriented relative to gravity at 4 degrees C. However, when returned to vertical at room temperature, these organs bend in response to the previous cold gravistimulation. The inflorescence stem of the Arabidopsis thaliana gravity persistent signal (gps) mutants respond abnormally after the cold gravistimulation: gps1 does not bend when returned to room temperature, gps2 bends the wrong way and gps3 over-responds, curving past the predicted angle. In wild type and the mutants, basipetal auxin transport in the inflorescence stem was abolished at 4 degrees C but restored when plants were returned to room temperature. In gps1, auxin transport was increased; in both gps2 and gps3, no significant difference was found when compared to wild type. Expression of the auxin-inducible P(IAA2)::GUS reporter gene, indicated that auxin-induced gene expression was redistributed to the lower side of the inflorescence stem in wild type after gravistimulation at 4 degrees C. In gps1, no asymmetries in P(IAA2)::GUS expression were seen. In gps2, P(IAA2)::GUS expression was localized to the upper side of the stem and in gps3, asymmetric P(IAA2):GUS expression was extended throughout the elongation zone of the inflorescence stem. These results are consistent with altered lateral Indole-3-acetic-acid (IAA) gradients being responsible for the phenotype of each mutant.