降水对日本菊花螺胚胎发育和幼体孵化的影响

作为常见的肺螺亚纲生物,日本菊花螺Siphonaria japonica(Donovan,1824)会将卵带产于潮间带岩石上,因此会经常遭受降水的影响。为阐明降水对日本菊花螺胚胎发育和幼体孵化的影响,本研究通过实验室模拟和野外原位取样相结合的方式分析了降水对卵带内胚胎发育状态、幼体累积孵化数、单位时间幼体孵化最高值和最高值出现时间的影响。结果表明:实验室模拟降水会显著影响卵带胚胎发育和幼体孵化(P0.05),但会显著加快幼体孵化速率(P<0.05)。国家自然科学基金资助项目(41476115)；福建省杰出青年基金项目滚动项目(2017J07003)~~

Temperature adaptation of cytosolic malate dehydrogenases of limpets (genus Lottia): differences in stability and function due to minor changes in sequence correlate with biogeographic and vertical distributions

We characterized functional and structural properties of cytoplasmic malate dehydrogenases (cMDHs) from six limpets of the genus Lottia that have different vertical and latitudinal distributions. Particular attention was given to the cryptic species pair Lottia digitalis (northern occurring) and L. austrodigitalis (southern occurring) because of recent contraction in the southern range of L. digitalis and a northward range extension of L. austrodigitalis. As an index of adaptation of function, we measured the effects of temperature on the apparent Michaelis-Menten constant (K(m)) of the cofactor NADH (K(m)(NADH)). K(m)(NADH) values of cMDHs from the mid- to high-intertidal, low-latitude species L. scabra and L. gigantea were less sensitive to high temperature than those of cMDHs from the low- and mid-intertidal, high-latitude species L. scutum and L. pelta. cMDH of L. digitalis was more sensitive to high temperatures than the cMDH ortholog of L. austrodigitalis. Thermal stability (rate of loss of activity at 42.5 degrees C) showed a similar pattern of interspecific variation. Comparison of the deduced amino acid sequences showed that interspecific differences ranged from one to as many as 17 residues. Differences in K(m)(NADH) and thermal stability between orthologs of L. digitalis and L. austrodigitalis result from a single amino acid substitution. At position 291, the glycine residue in cMDH of L. digitalis is replaced by a serine in cMDH of L. austrodigitalis, a change that favors additional hydrogen bonding and reduced conformational entropy. This difference between closely related congeners demonstrates the role of minor alterations in protein sequence in temperature adaptation and suggests that such variation is important in governing shifts in biogeographic range in response to climate change

THE EFFECT of HIGH AMMONIA CONCENTRATION ON GILL STRUCTURE ALTERNATION AND EXPRESSION of SOD AND HSP90 GENES IN GRASS CARP,CTENOPHARYNGODON IDELLA

实验通过测定草鱼的24H半致死浓度,鳃的细胞结构以及SOd和HSP90的表达模式研究了草鱼在组织学和分子生物学水平上对高浓度氨氮暴露的响应。经过半致死实验确定的氨氮24H lC50为243 Mg/l试验中草鱼被置于5个浓度的处理组中(50、72、104、151、220 Mg/l),之后取鳃组织进行组织切片分析,取肝脏、肠和鳃来测定SOd和HSP90的表达情况。经过高浓度的氨氮暴露处理,鳃组织的细胞排列和结构产生了明显的变化,并且SOd和HSP90的表达受到了显著的上调。这些结果表明,高浓度的氨氮能够损害鳃部的细胞结构并且诱导应激蛋白的表达。这个结果同样显示出,SOd和HSP90可以作为评估草鱼氨氮暴露水平的良好指标。Histological and molecular responses of grass carp Ctenopharyngodon idella to high concentration ammonia exposure were studied in this study by determining the lethal concentration,gill cellular structure,and expression patterns of sod and hsp90 genes.Grass carps were treated at five ammonia concentrations(50,72,104,151 and 220 mg/L) for 24h,and then the gill tissues were collected for histological analysis.In addition,three tissues(gill,intestine and liver) were collected to measure the expression of sod and hsp90 genes.After exposure to high concentration of ammonia,the arrangement and structures of gill cells changed dramatically.Edema and fusion of secondary lamellae were observed,and the edge of cell and nucleus could not be clearly defined.Meanwhile,the two genes(sod and hsp90) in different tissues were unregulated significantly,indicating that high concentration of ammonia could impair the cellular structures and induce the expression of stress proteins.These results also suggested that sod and hsp90 were suitable biomarkers for ammonia exposure assessment in grass carp.FoundsoftheNationalProgramonKeyBasicResearchProject(2009CB118706

Growth and oxygen consumption of the juvenile sea cucumber Apostichopus japonicus (Selenka) at constant and fluctuating water temperatures

The effects of thermal amplitudes of diel fluctuating temperature on growth and oxygen consumption of the juvenile sea cucumber Apostichopus japonicus (Selenka) were studied at the average temperatures of 15 and 18 degrees C with three diel different fluctuating amplitudes of +/- 2, +/- 4 and +/- 6 degrees C. The optimum thermal amplitudes for growth of the juvenile sea cucumber at the sizes of this experiment, at average temperatures of 15 and 18 degrees C, were estimated to be +/- 1.38 and +/- 1.67 degrees C respectively. In the constant temperature regimes, the growth rate at 15 degrees C was higher than that at 18 degrees C. However, the growth rate at 18 +/- 2 degrees C was higher than that at 15 +/- 2 degrees C. The results from this study suggested that fluctuating temperatures enhanced the optimum temperature for the growth of sea cucumbers compared with that at constant temperatures. Therefore, accurate predictions of the optimum temperature of sea cucumbers in the natural environment, in which water temperatures fluctuate daily and seasonally, should be made from data obtained at fluctuating temperatures

Growth and physiological responses in the sea cucumber, Apostichopus japonicus Selenka: Aestivation and temperature

Aestivation is an adaptation of the sea cucumber Apostichopus japonicus Selenka to high temperature, however, the causations and physiological responses of aestivation are not well understood. This study deals with the relationship between temperature and aestivation. Sea cucumbers were allocated into four treatments. In two treatments of temperature elevation, the ambient temperature gradually was increased from 16 degrees C to 26 degrees C linearly (treatment FA) or by a fluctuating temperature profile (treatment FB). Two control treatments maintained constant temperatures of 16 degrees C and 26 degrees C, and were designated as optimum temperature of growth and threshold of aestivation, respectively. During the 40-day experiment, body weight, oxygen consumption, daily food intake, catalase (CAT) and superoxide dimutase (SOD) activities and heat shock protein 70 (Hsp70) levels were determined periodically. When the temperature gradually increased from 16 degrees C to 26 degrees C, the body weight of the tested sea cucumbers decreased gradually. After the ambient temperature reached 26 degrees C, the tested sea cucumbers in treatments of FA and F13 were reared at 26 degrees C for an additional twenty days. During this period, symptoms of aestivation appeared in the tested sea cucumbers. Activities of antioxidases and Hsp70 levels increased when the ambient temperature increased from 16 degrees C to 26 degrees C, and decreased when the temperature was kept at 26 degrees C. These results indicate that aestivation in A. japonicurs is an adaptive strategy to reduce the production of reactive oxygen species (ROS) and denatured proteins which were induced at high temperature. (C) 2008 Elsevier B.V. All rights reserved

Heat-Shock Protein 70 (Hsp70) Expression in Four Limpets of the Genus \u3cem\u3eLottia\u3c/em\u3e: Interspecific Variation in Constitutive and Inducible Synthesis Correlates With \u3cem\u3ein situ\u3c/em\u3e Exposure to Heat Stress

Limpets of the genus Lottia occupy a broad vertical distribution on wave-exposed rocky shores, a range that encompasses gradients in the frequency and severity of thermal and desiccation stress brought on by aerial emersion. Using western blot analysis of levels of heat-shock protein 70 (Hsp70), we examined the heat-shock responses of four Lottia congeners: Lottia scabra and L. austrodigitalis, which occur in the high-intertidal zone, and L. pelta and L. scutum, which are restricted to the low- and mid-intertidal zones. Our results suggest distinct strategies of Hsp70 expression in limpets occupying different heights and orientations in the rocky intertidal zone. In freshly field-collected animals and in specimens acclimated at ambient temperature (≈14 °C) for 14 days, the two high-intertidal species had higher constitutive levels of Hsp70 than the low- and mid-intertidal species. During aerial exposure to high temperatures, the two low-shore species and L. austrodigitalis exhibited an onset of Hsp70 expression at 28 °C; no induction of Hsp70 occurred in L. scabra. Our findings suggest that high-intertidal congeners of Lottia employ a “preparative defense” strategy involving maintenance of high constitutive levels of Hsp70 in their cells as a mechanism for protection against periods of extreme and unpredictable heat stress

Effects of parent acclimation and heat-shock at gastrula on growth and development of sea cucumber larvae

文章探讨了刺参(APOSTICHOPuS JAPOnICuS)亲本南方驯化和囊胚期幼体热应激对浮游幼体生长、发育的影响。刺参亲本分为未度夏(dA)组和已度夏(XP)组,每组设置对照组(C)和热应激组(H),在囊胚期对H组进行45MIn、26℃的高温应激,然后分别在18℃和23℃下培育至变态。结果表明,培育温度对H组和C组幼体的生长有显著影响,C组幼体在23℃下的特定生长率高于18℃,而H组正好相反。从耳状幼体第2天开始,dA组和XP组幼体的最大体长开始出现在H组,这与幼体对饵料的摄取有关。H组幼体的变态率要显著低于C组,这归因于高温应激导致的高畸形率。dA组和XP组幼体的生长、成活以及附着变态率之间差异不显著。鉴于之前研究结果,可通过下述途径获取耐高温刺参苗种:首先在囊胚期进行高温应激获取耐高温幼参,然后在南方进行幼体培育和中间养成,性成熟后进行苗种繁育,最后经过累代选育固定耐高温性状。This study investigated the effects of parent-acclimation and heat-shock at gastrula stage on growth and development of sea cucumber( Apostichopus japonicus) larvae.The adult sea cucumbers were split into two groups: DA group and XP group,each with two treatments: control( C) and heat-shock( H).Gastrula larvae of H were heated at 26 ℃ for 45 min and then reared at 18 ℃ and23 ℃ separately until metamorphosis.Results show that the specific growth rate at 23 ℃ was higher than that at 18 ℃ in the control,but the trend was opposite in heat-shock treatment.Since the 2ndday of auricularia,the maximum body length had been observed in heat-shock treatment for both DA and XP group,which was due to the ingestion of food.The setting rate of heat-shock treatment was significantly lower than that of the control due to the high rate of deformed individuals caused by heat-shock.Thus,high temperatureresistant sea cucumbers can be acquired via the following steps: first,obtain a certain number of high temperature-resistant juveniles by heat-shock at gastrula stage; then,culture these individuals in southern China until sexual maturity; finally,fix the high temperature-resistant properties by generation selection.中国博士后科学基金(2013M541862); 福建省杰出青年基金(2011J06017

Physiological Responses in a Variable Environment: Relationships between Metabolism, Hsp and Thermotolerance in an Intertidal-Subtidal Species

Physiological responses to temperature reflect the evolutionary adaptations of organisms to their thermal environment and the capability of animals to tolerate thermal stress. Contrary to conventional metabolism theory, increasing environmental temperatures have been shown to reduce metabolic rate in rocky–eulittoral-fringe species inhabiting highly variable environments, possibly as a strategy for energy conservation. To study the physiological adaptations of an intertidal-subtidal species to the extreme and unpredictable heat stress of the intertidal zone, oxygen consumption rate and heat shock protein expression were quantified in the sea cucumber Apostichopus japonicus. Using simulate natural temperatures, the relationship between temperature, physiological performance (oxygen consumption and heat shock proteins) and thermotolerance were assessed. Depression of oxygen consumption rate and upregulation of heat shock protein genes (hsps) occurred in sequence when ambient temperature was increased from 24 to 30°C. Large-scale mortality of the sea cucumber occurred when temperatures rose beyond 30°C, suggesting that the upregulation of heat shock proteins and mortality are closely related to the depression of aerobic metabolism, a phenomenon that is in line with the concept of oxygen- and capacity-limited thermal tolerance (OCLTT). The physiologically-related thermotolerance of this sea cucumber should be an adaptation to its local environment

不同气氛下热处理对CO甲烷化催化剂性能的影响

采用液相包裹法制备了Ni/Al2O3耐高温甲烷化催化剂,并分别在静态空气、动态氮气及动态空气气氛条件下程序升温到550oC,恒温煅烧,得到不同气氛下热处理的三种催化剂。通过BET,H2-TPR,XPS等一系列的表征分析结果显示,经过动态气氛下煅烧的催化剂在高温和低温都具备良好的活性,其具有较大的比表面积,且流动性的气体可以有效的降低催化剂中镍与载体的结合力,主要表现在氧化镍的化学位能降低0.5eV,镍更易于还原

Thermal adaptation of enzymes

董云伟团队在潮间带生物生化适应机制的研究过程中，结合分子动力学模拟和实验调控手段，发现极端高温下，耐热滨螺能够通过增强代谢关键酶的作用，避免蛋白质的解链，保持微结构完整和功能维持；通过对原位体温跨度达60℃的12种软体动物的研究，定量了cMDH结构柔性的温度适应性变化程度，揭示了氨基酸温度适应性进化的关键位点，阐述了蛋白质结构稳定性与生物地理分布的内在联系。将海洋软体动物生化适应研究从单一的定性实验，拓展到了基于计算生物学的定量研究，揭示了海洋软体动物细胞质苹果酸脱氢酶（cMDH）结构稳定性和功能适应性的趋同进化模式，建立了基于代谢关键酶的“酶促动力学—蛋白合成—模拟计算”的生化适应机制的创新性研究模式。基于上述基础，课题组进一步拓展研究的深度与广度，比较分析了从南极洲半致死温度仅为4℃的扇贝，到中国沿海可耐受60℃以上高温的滨螺等26种海洋软体动物 cMDH 的温度耐受性，提出了蛋白质不同区域氨基酸的温度适应性变化模式，通过分子动力学分析揭示了具有重要功能的区域及其作用机制。这一系列研究成果加深了对海洋生物蛋白质温度适应机制的认识，为该领域提供了新的研究模式与思路，对于查明环境温度对生物分布的影响及其机制，预测气候变暖的生态学效应具有重要意义。董云伟团队致力于潮间带生态学研究，重点研究潮间带生物对复杂环境条件的响应特征和时空规律，及其适应机制。近年来研究主要集中在潮间带生物生化适应机制、生理调节策略及地理格局变化等方面。【Abstract】Comparative studies of orthologous proteins of species evolved at different temperatures have revealed consistent patterns of temperature-related variation in thermal stabilities of structure and function. However, the precise mechanisms by which interspecific variations in sequence foster these adaptive changes remain largely unknown. Here, we compare orthologs of cytosolic malate dehydrogenase (cMDH) from marine molluscs adapted to temperatures ranging from -1.9℃ (Antarctica) to～55℃ (South China coast) and show how amino acid usage in different regions of the enzyme (surface, intermediate depth, and protein core) varies with adaptation temperature. This eukaryotic enzyme follows some, but not all of the rules established in comparisons of archaeal and bacterial proteins. To link the effects of specific amino acid substitutions with adaptive variations in enzyme thermal stability we combined site-directed mutagenesis (SDM) and in vitro protein experimentation with in silico mutagenesis using molecular dynamics simulation (MDS) techniques. SDM and MDS methods generally, but not invariably yielded common effects on protein stability. MDS analysis is shown to provide insights into how specific amino acid substitutions affect the conformational flexibilities of mobile regions (MRs) of the enzyme that are essential for binding and catalysis. Whereas these substitutions invariably lie outside of the MRs, they effectively transmit their flexibility-modulating effects to the MRs through linked interactions among surface residues. This discovery illustrates that regions of the protein surface lying outside of the site of catalysis can help establish an enzyme’s thermal responses and foster evolutionary adaptation of function.This work was supported by National Natural Science Foundation of China Grants 41776135 and 41476115 (to Y.-w.D.) and Nature Science Funds for Distin-guished Young Scholars of Fujian Province, China Grant 2017J07003 (to Y.-w.D.). Work in the collection of the Antarctic specimens was supported by National Science Foundation Grant 1245703 (to Donal Manahan, co-PI).该成果得到国家自然科学基金项目（项目编号：41776135、41476115）和福建省杰出青年基金（2017J07003）资助