Global whole-cell FTICR mass spectrometric proteomics analysis of the heat shock response in the radioresistant bacterium Deinococcus radiodurans

The results of previous studies indicated that D. radiodurans mounts a regulated protective response to heat shock, and that expression of more than 130 genes, including classical chaperones such as the groESL and dnaKJ operons and proteases such as clpB are induced in response to elevated temperature. In addition, previous qualitative whole-cell mass spectrometric studies conducted under heat shock conditions indicated global changes in the D. radiodurans proteome. To enable the discovery of novel heat shock inducible proteins as well as gain greater biological insight into the classical heat shock response at the protein level, we undertook the global whole-cell FTICR mass spectrometric proteomics study reported here. We have greatly increased the power of this approach by conducting a large number of replicate experiments in addition to taking a semiquantitative approach to data analysis, finding good reproducibility between replicates. Through this analysis, we have identified with high confidence a core set of classical heat shock proteins whose expression increases dramatically and reproducibly in response to elevated temperature. In addition, we have found that the heat shock proteome includes a large number of induced proteins that have not been identified previously as heat responsive, and have therefore been designated as candidate responders. Finally, our results are consistent with the hypothesis that elevated temperature stress could lead to cross-protection against other related stresses.     

Effects of heat shock and ambient temperature on female soldier production in a polyembryonic parasitic wasp

Larval castes are well known in both sexes of polyembryonic parasitic wasps, in which sterile soldier larvae are clonally produced from a single egg and thousands of reproductive larvae develop into adults. The proportion of soldier larvae in Copidosoma floridanum is first determined genetically in both sexes but subsequently increases in females as a result of environmental disturbances, such as the presence of competitive parasitoids. Because temperature is the most influential environmental factor affecting ectotherms, we hypothesize that an increase in ambient temperature also affects the production of female soldier larvae. Conversely, we hypothesize that there would be no effect of temperature on the production of male soldier larvae. In the present study, we show that heat stress experienced by C. floridanum at an early stage in host development increases the number of female soldier larvae produced during the last instar stage of the host. We also show that rearing at extreme (high and low) temperatures induces an increase in the number of female soldiers produced. The effect of heat stress and ambient temperature on soldier production is found only in females, as is the response to heterospecific competitors. By contrast, no responses are detected in males for either heat stress or ambient temperature. The adaptive effect of these phenomena is not known, although the results of the present study imply the existence of a common physiological cascade that causes an increase in the number of soldier larvae in females.     

温度刺激对斑马鱼仔鱼基因转录表达的影响

许多优良鱼类养殖品种不耐低温或高温的特点给水产养殖业带来诸多限制和困难,这些鱼类在胚胎和仔鱼等早期阶段的抗寒和抗热能力比成体更差,育苗过程中很容易受到温度突然变化的影响。虽然目前利用基因芯片技术已研究了温度刺激对几种鱼类成体组织中基因表达的影响,但温度刺激对仔鱼基因转录表达的影响还未见报道。研究以斑马鱼受精后96h的出膜仔鱼为实验材料,分别在低温(16℃)和高温(34℃)条件下处理12h和24h,用基因芯片技术检测温度刺激对其基因表达的影响。与培养在28℃的对照相比,低温和高温处理后共有3633个基因发生差异表达,其中低温处理后差异表达基因数目多于高温处理,而且低温抑制基因数目多于诱导表达基因的数目。生物信息学分析结果表明,低温诱导基因主要参与RNA加工和核糖体生物发生等生物学过程,高温诱导基因则主要参与应激反应和未折叠蛋白结合。低温抑制基因主要参与蛋白质水解、视觉感知以及铁离子结合等生物学功能,高温抑制基因参与的生物学功能包括DNA复制、神经系统过程和类固醇激素生物合成等。除了已报道的温度刺激响应基因外,研究鉴定出了大量尚未报道与温度刺激相关的基因,如参与RNA加工的rnmtl1a和pus3基因,以及参与转录调控的twistnb和aebp2基因等。研究结果为进一步揭示鱼类冷或热适应的分子机理和培养耐寒或耐热的养殖新品种提供理论基础。     

Rice yield formation under high day and night temperatures—A prerequisite to ensure future food security

Increasing temperatures resulting from climate change dramatically impact rice crop production in Asia. Depending on the specific stage of rice development, heat stress reduces tiller/panicle number, decreases grain number per plant and lower grain weight, thus negatively impacting yield formation. Hence improving rice crop tolerance to heat stress in terms of sustaining yield stability under high day temperature (HDT), high night temperature (HNT), or combined high day and night temperature (HDNT) will bolster future food security. In this review article, we highlight the phenological alterations caused by heat and the underlying molecular-physiological and genetic mechanisms operating under different types of heat conditions (HDT, HNT, and HDNT) to understand heat tolerance. Based on our synthesis of HDT, HNT, and HDNT effects on rice yield components, we outline future breeding strategies to contribute to sustained food security under climate change.     

MHD Free Convective Boundary Layer Flow of a Nanofluid past a Flat Vertical Plate with Newtonian Heating Boundary Condition

Steady two dimensional MHD laminar free convective boundary layer flows of an electrically conducting Newtonian nanofluid over a solid stationary vertical plate in a quiescent fluid taking into account the Newtonian heating boundary condition is investigated numerically. A magnetic field can be used to control the motion of an electrically conducting fluid in micro/nano scale systems used for transportation of fluid. The transport equations along with the boundary conditions are first converted into dimensionless form and then using linear group of transformations, the similarity governing equations are developed. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order method with shooting technique. The effects of different controlling parameters, namely, Lewis number, Prandtl number, buoyancy ratio, thermophoresis, Brownian motion, magnetic field and Newtonian heating on the flow and heat transfer are investigated. The numerical results for the dimensionless axial velocity, temperature and nanoparticle volume fraction as well as the reduced Nusselt and Sherwood number have been presented graphically and discussed. It is found that the rate of heat and mass transfer increase as Newtonian heating parameter increases. The dimensionless velocity and temperature distributions increase with the increase of Newtonian heating parameter. The results of the reduced heat transfer rate is compared for convective heating boundary condition and found an excellent agreement.     

Effect of Joule Heating and Thermal Radiation in Flow of Third Grade Fluid over Radiative Surface

This article addresses the boundary layer flow and heat transfer in third grade fluid over an unsteady permeable stretching sheet. The transverse magnetic and electric fields in the momentum equations are considered. Thermal boundary layer equation includes both viscous and Ohmic dissipations. The related nonlinear partial differential system is reduced first into ordinary differential system and then solved for the series solutions. The dependence of velocity and temperature profiles on the various parameters are shown and discussed by sketching graphs. Expressions of skin friction coefficient and local Nusselt number are calculated and analyzed. Numerical values of skin friction coefficient and Nusselt number are tabulated and examined. It is observed that both velocity and temperature increases in presence of electric field. Further the temperature is increased due to the radiation parameter. Thermal boundary layer thickness increases by increasing Eckert number.     

Physiological factors limit fruit set of tomato (Lycopersicon esculentum Mill.) under chronic, mild heat stress

The effects of chronic, mild heat stress on fruit set, fruit production, release of pollen grains, photosynthesis, night respiration and anther dehiscence were examined in tomatoes (Lycopersicon esculentum Mill.) differing in high‐temperature sensitivity. Plants were grown under three temperature regimes: (1) 28/22 or 26/22 °C (optimal temperature); (2) 32/26 °C (high temperature); and (3) 32/26 °C day/night temperatures relieved at 28/22 °C for 10 d before anthesis, then returned to 32/26 °C (relieving treatment). FLA 7156 was the only cultivar with fruit set at 32/26 °C. All five cultivars, however, had fruit set under the relieving treatment (RT). The longer the relief, the higher the percentage of fruit set. Longer periods of relief also increased the number of pollen grains released, and linear regression analysis showed a significant relationship between the number of pollen grains released and the percentage of fruit set. Germination of pollen grains was also lowered in high‐temperature‐grown plants. The number of pollen grains produced, photosynthesis and night respiration did not limit fruit set under chronic, mild heat stress, however. This suggested that cultivar differences in pollen release and germination under heat stress are the most important factors determining their ability to set fruit.     

地方稻资源D43的开花期耐热特性研究

水稻在抽穗开花期对高温胁迫非常敏感,通过挖掘耐热资源,培育耐热水稻品种是应对高温热害最有效的方式。前期研究发现,地方稻资源D43在花期连续高温条件下能保持较高的结实率。本研究在大田和人工气候室不同高温处理下,分析了D43的开花时间与耐热性之间的相互关系。结果表明,高温能够使水稻的开花时间提前,D43表现出稳定的早花时特性,高温胁迫下的开花时间集中在8∶30~10∶00;在开花时间段恒定高温胁迫下,D43的结实率较低;但在大田高温和人工气候室模拟高温胁迫下,D43的开花时间避开了日高温段,从而表现出较高的结实率;花器官形态性状包括花药开裂率、柱头上的花粉附着数、花粉萌发数与结实率之间呈显著正相关,因此可用于评价水稻的花期耐热性。     

Double Diffusive Magnetohydrodynamic (MHD) Mixed Convective Slip Flow along a Radiating Moving Vertical Flat Plate with Convective Boundary Condition

In this study combined heat and mass transfer by mixed convective flow along a moving vertical flat plate with hydrodynamic slip and thermal convective boundary condition is investigated. Using similarity variables, the governing nonlinear partial differential equations are converted into a system of coupled nonlinear ordinary differential equations. The transformed equations are then solved using a semi-numerical/analytical method called the differential transform method and results are compared with numerical results. Close agreement is found between the present method and the numerical method. Effects of the controlling parameters, including convective heat transfer, magnetic field, buoyancy ratio, hydrodynamic slip, mixed convective, Prandtl number and Schmidt number are investigated on the dimensionless velocity, temperature and concentration profiles. In addition effects of different parameters on the skin friction factor, , local Nusselt number, , and local Sherwood number are shown and explained through tables.     

Thermal chip fabrication with arrays of sensors and heaters for micro-scale impingement cooling heat transfer analysis and measurements

The design and fabrication for a thermal chip with an array of temperature sensors and heaters for study of micro-jet impingement cooling heat transfer process are presented. This thermal chip can minimize the heat loss from the system to the ambient and provide a uniform heat flux along the wall, thus local heat transfer processes along the wall can be measured and obtained. The fabrication procedure presented can reach a chip yield of 100%, and every one of the sensors and heaters on the chip is in good condition. In addition, micro-jet impingement cooling experiments are performed to obtain the micro-scale local heat transfer Nusselt number along the wall. Flow visualization for the micro-impinging jet is also made. The experimental results indicate that both the micro-scale impinging jet flow structure and the heat transfer process along the wall is significantly different from the case of large-scale jet impingement cooling process.     

Heat shock proteins: functions and role in adaptation to hyperthermia

The results are generalized of many-year studies into the adaptive role of heat shock proteins in different animals, including the representatives of cold- and warm-blooded species that inhabit regions with different thermal conditions. Adaptive evolution of the response to hyperthermia can lead to different results depending on the species. The thermal threshold of induction of the heat shock proteins in desert thermophylic species is, as a rule, higher than in the moderate climate species. In addition, thermoresistant species are often characterized by a certain level of heat shock proteins in cells even at a physiologically normal temperature. Although adaptation to hyperthermia is achieved in most cases without changes in the number of heat shock genes, they can be amplified in some cases in termophylic species. The role of mobile elements in evolution of the heat shock genes was shown and approach was developed for directional introduction of mutations in the promoter regions of these genes.     

A sporulation medium for strict anaerobes

The production of spores, and spore position and shape, are taxonomic criteria in a number of genera of bacteria. The heat resistance of spores is also of interest taxonomically and with respect to the survival of bacteria, particularly pathogens, in a number of habitats. The demonstration of spore formation by growth of bacteria in various standard media and under different conditions (e.g. at sub-optimum temperature) is often not easy. Thus, a number of media designed to encourage spore formation and to produce spores with maximum heat resistance have been introduced, for instance for Clostridium perfringens (Ellner 1956; Angelotti et al. 1962; Kim et al. 1967; Duncan & Strong 1968) and Sporolactobacillus inulinus (Kitahara & Lai 1967).     

Thermal energy conduction in a honey bee comb due to cell-heating bees

Theoretical analysis and numerical calculations are performed to characterize the unsteady two-dimensional conduction of thermal energy in an idealized honey bee comb. The situation explored corresponds to a comb containing a number of brood cells occupied by pupae. These cells are surrounded by other cells containing pollen which, in turn, are surrounded (above) by cells containing honey and (below) by vacant cells containing air. Up to five vacant cells in the brood region can be occupied by cell-heating bees which, through the isometrical contraction of their flight muscles, can generate sufficient energy to raise their body temperatures by a few degrees. In this way, the cell-heating bees alter the heat flux and temperature distributions in the brood region so as to maintain conditions that benefit the pupae. The calculations show that the number of cell-heating bees significantly affects the magnitude, time rate of change, and spatial distribution of temperature throughout the comb. They also reveal a vertically aligned asymmetry in the spatial distribution of temperature that is due to the large heat capacity and thermal conductivity of honey relative to air, whereby air-filled cells experience larger temperature increases than honey-filled cells. Analysis shows that convection and radiation represent negligible modes of thermal energy transfer at all levels in the problem considered. Also, because of its small thickness, the wax wall of a comb cell simultaneously presents negligible resistance to conduction heat transfer normal to it and very large resistance along it. As a consequence the walls of a cell play no thermal role, but simply serve as mechanical supports for the materials they contain.     

The association of extreme temperatures and the incidence of tuberculosis in Japan

Seasonal variation in the incidence of tuberculosis (TB) has been widely assumed. However, few studies have investigated the association between extreme temperatures and the incidence of TB. We collected data on cases of TB and mean temperature in Fukuoka, Japan for 2008–2012 and used time-series analyses to assess the possible relationship of extreme temperatures with TB incident cases, adjusting for seasonal and interannual variation. Our analysis revealed that the occurrence of extreme heat temperature events resulted in a significant increase in the number of TB cases (relative risk (RR) 1.20, 95 % confidence interval (CI) 1.01–1.43). We also found that the occurrence of extreme cold temperature events resulted in a significant increase in the number of TB cases (RR 1.23, 95 % CI 1.05–1.45). Sex and age did not modify the effect of either heat or cold extremes. Our study provides quantitative evidence that the number of TB cases increased significantly with extreme heat and cold temperatures. The results may help public health officials predict extreme temperature-related TB incidence and prepare for the implementation of preventive public health interventions.     

Air movement and heat loss from sheep. I. Boundary layer insulation of a model sheep, with and without fleece

A model sheep, made from metal cylinders and hemispheres, was heated electrically. Heat loss by forced convection in a wind tunnel was analysed in terms of the dependence of the Nusselt number (Nu) on Reynolds number (Re). For a bare trunk Nu = 0.095 Re0.684, but with fleece covering the trunk to a depth of 3.5 cm, Nu = 0.0112 Re0.875 when the mean radiative temperature of the the coat was taken as the surface temperature. Heat transfer by convection from the whole body, including legs, was described by Nu = 0.029 Re0.80. However, a bulk Nesselt number should not be used to estimate heat loss from a live sheep in a hot environment if the windspeed is below about 4 m s-1 because the relation between mean surface temperature, Nusselt number and convective heat flux is not unique.     

An overview of heat stress in tomato (Solanum lycopersicum L.)

Heat stress has been defined as the rise of temperature for a period of time higher than a threshold level, thereby permanently affecting the plant growth and development. Day or night temperature is considered as the major limiting factor for plant growth. Earlier studies reported that night temperature is an important factor in the heat reaction of the plants. Tomato cultivars capable of setting viable fruits under night temperatures above 21 °C are considered as heat-tolerant cultivars. The development of breeding objectives is generally summarized in four points: (a) cultivars with higher yield, (b) disease resistant varieties in the 1970s, (c) long shelf-life in 1980s, and (d) nutritive and taste quality during 1990s. Some unique varieties like the dwarf “Micro-Tom”, and the first transgenic tomato (FlavrSavr) were developed through breeding; they were distributed late in the 1980s.High temperature significantly affects seed, pollen viability and root expansion. Researchers have employed different parameters to evaluate the tolerance to heat stress, including membrane thermo stability, floral characteristics (Stigma exertion and antheridia cone splitting), flower number, and fruit yield per plant. Reports on pollen viability and fruit set/plant under heat stress by comparing the pollen growth and tube development in heat-treated and non-heat-stressed conditions are available in literature. The electrical conductivity (EC) have been used to evaluate the tolerance of some tomato cultivars in vitro under heat stress conditions as an indication of cell damage due to electrolyte leakage; they classified the cultivars into three groups: (a) heat tolerant, (b) moderately heat tolerant, and (c) heat sensitive.It is important to determine the range in genetic diversity for heat tolerance in tomatoes. Heat stress experiments under field conditions offer breeders information to identify the potentially heat tolerant germplasm.     

Moderate heat stress of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> leaves causes chloroplast swelling and plastoglobule formation

Photosynthesis is inhibited by heat stress. This inhibition is rapidly reversible when heat stress is moderate but irreversible at higher temperature. Absorbance changes can be used to detect a variety of biophysical parameters in intact leaves. We found that moderate heat stress caused a large reduction of the apparent absorbance of green light in light-adapted, intact Arabidopsis thaliana leaves. Three mechanisms that can affect green light absorbance of leaves, namely, zeaxanthin accumulation (absorbance peak at 505 nm), the electrochromic shift (ECS) of carotenoid absorption spectra (peak at 518 nm), and light scattering (peak at 535 nm) were investigated. The change of green light absorbance caused by heat treatment was not caused by changes of zeaxanthin content nor by the ECS. The formation of non-photochemical quenching (NPQ), chloroplast movements, and chloroplast swelling and shrinkage can all affect light scattering inside leaves. The formation of NPQ under high temperature was not well correlated with the heat-induced absorbance change, and light microscopy revealed no appreciable changes of chloroplast location because of heat treatment. Transmission electron microscopy results showed swollen chloroplasts and increased number of plastoglobules in heat-treated leaves, indicating that the structural changes of chloroplasts and thylakoids are significant results of moderate heat stress and may explain the reduced apparent absorbance of green light under moderately high temperature.     

Effect of the post-dry heat treatment temperature on the recovery of ascospores of Neosartorya fischeri

Neosartorya fischeri ascospores were subjected to a dry heat treatment at 95°C, 50% relative humidity for 30 and 60 min. The effect of the temperature of the recovery buffer (0–02% v/v Tween 80 in Butterfield's Buffer) was evaluated. As the temperature of the buffer increased, there was an exponential increase in the number of survivors, followed by a levelling off and, in some cases, a decrease. This behaviour may indicate temperature activation of dormant ascospores or reactivation of ascospores rendered dormant by the dry heat treatment. The results also suggest that the rehydration process is affected by temperature.     

Circular dichroism of DNA: temperature and salt dependence

The temperature dependence of the circular dichroism and ultraviolet absorbance of calf thymus DNA and poly dAT were measured in aqueous solutions of various 1–1 electrolytes. Although there was very little change in absorbance, the circular dichroism changed dramatically as a function of both temperature and solvent. There is a correlation of the heat of hydration of the cation and the magnitude of the temperature dependence of the circular dichroism. Our results are interpreted in terms of a large number (possibly a continuum) of intermediate secondary structures.