Effect of thermal stress on Hsp70 gene expression and female reproductive performance of giant freshwater prawn,Macrobrachium rosenbergii

Using Hsp70 as a biomarker, thermal stress impinges on reproductive organs, ovary and hepatopancreas were being analyzed by determining the expression of Hsp70 mRNA inside the organs after the adult inter‐molt females were subjected to thermal treatment at 35, 30 and 28°C (Control). Results showed the expression of Hsp70 mRNA under thermal treatment of 35°C after 2 hr recovery in ovary were upregulated at 2, 4, 6, 12, 24 hr and 30 days compared to control whereas in hepatopancreas under similar treatment, the expression of Hsp70 mRNA were significantly higher than control at 6, 24 hr and 30 days. Frequency of reproductive molt at 35°C showed the ovary of females were failed to develop and only entered common molt along three consecutive molt cycles. For 30°C thermal treatment, the expression of Hsp70 mRNA was significantly higher than control after 2 hr recovery but returned to normal afterwards until 30 days’ thermal treatment. Maternal heat shock for 2 hr at 35°C were found to give significantly lower frequency of reproductive molt and longer duration of ovarian development and incubation period whereas maternal heat shock for 2 hr at 30°C gave lower frequency of reproductive molt, slower development of embryo and lower hatching success compared to untreated control. This study suggests that short and long‐term thermal stress at 30 and 35°C were found to affect the induction of Hsp70 mRNA in reproductive organs of Macrobrachium rosenbergii and also influence their reproductive performance.     

斑马鱼雄核发育技术研究

为探索人工诱导斑马鱼雄核发育二倍体克隆鱼的途径和方法,运用紫外线照射卵子使其遗传物质失活,利用斑马鱼体表花纹形态作为遗传标记,使用热休克技术阻止受精卵的第一次卵裂加倍染色体。试验结果表明总辐射剂量为120mJ cm2紫外线照射斑马鱼卵可以使雌核遗传物质完全失活;体表花纹为豹斑花纹被证实是由纯合隐性基因控制的性状,可以作为雄核发育遗传标记;遗传失活卵受精后经2min,(41 5±0 5)℃的热休克后出现两个染色体加倍的高峰期,分别为受精后的11min和23min,且后一时期效果优于前一时期,最高二倍体诱导率达46 15%;经遗传分析,共获得正常存活的雄核发育二倍体克隆鱼19尾,说明经过优化的紫外线结合热休克等染色体操作技术,可以成为诱导雄核发育二倍体克隆鱼的有效手段。     

Heat shock protein 70 expression in different tissues of Cirrhinus mrigala (Ham.) following heat stress

Members of heat shock protein 70 (HSP70) are highly conserved proteins of about 70 kDa and play important roles in protein folding. Levels of these proteins increase when cells are under stress. Environmental temperature influences both the basal and induced levels of HSPs. However, studies on HSPs in fishes from a tropical country such as India are lacking. In the present study, Indian major carp (IMC) Cirrhinus mrigala (Ham.) acclimatized at 25±2°C had high levels of HSP70, viz., 1.2–1.3 ng μg^?1 total protein in kidney and gill and 4.2–5.3 ng μg^?1 total protein in liver and brain tissues, indicating the presence of biochemically significant levels of stress. However, maintenance of acclimatized fish at 17°C for up to 48 h did not lead to a significant decrease in stress protein levels. A heat shock at 37°C for up to 48 h resulted in only two to threefold increase in HSP70 levels in these organs. Although the increase in HSP70 levels was apparent from the first hour of heat stress in all these tissues, the increase was significant from the second hour in the brain, the sixth hour in liver and kidney and the 20th hour in the gills.     

双斑东方鲀三倍体育苗生产性研究

采用温度休克方法诱导双斑东方鲀三倍体,在水温18-20℃条件下,卵受精后5分钟用40℃的水处理双斑东方鲀受精卵10分钟,三倍体诱导率100％,孵化率相对诱导量达25％;育苗采用前期室内工厂化培育与后期土池培育相结合方法,培育出全为三倍体(体长3 cm以上)苗种5．8万尾,对应孵出苗量,成活率为34．6％。     

异源精子诱导犬齿牙鲆的雌核发育

用冷冻保存的花鲈精子作为异源精子,采用紫外线(UV)对精子进行照射使其遗传物质失活,然后与卵子进行"授精",可以刺激犬齿牙鲆鱼卵进行雌核发育,在受精后一定时间采用冷休克处理"授精"卵,抑制第二极体排出成功获得了犬齿牙鲆雌核发育二倍体鱼苗.实验表明:犬齿牙鲆同源精子经80 mJ/cm2的紫外线照射可以完全失活,冻存花鲈精子经紫外线照射后也同样具有诱导犬齿牙鲆雌核发育的能力.无论同源精子还是异源精子,最佳诱导条件为在18℃条件下,精子经80 mJ/cm2的紫外线照射,受精后4～5 min将受精卵放在3℃海水中进行冷休克处理,持续时间为45 min,同源精子和异源精子二倍体诱导分别为32.66%±7.03%和28.00%±6.48%.采用形态学、流式细胞仪DNA含量分析和微卫星标记技术对雌核发育鱼苗进行了分析,证明了雌核发育鱼苗为雌核发育二倍体.     

冷、热休克法诱导黄颡鱼三倍体的比较研究

分别采用冷、热休克抑制第二极体释放的方法诱导黄颡鱼三倍体。结果表明,在卵受精后2min,5℃处理20min,胚胎时期的三倍体率达70%左右,孵化率50%左右,幼鱼时期三倍体(含嵌合体)的检出率为25%,此条件为冷休克处理的优化参数;在卵受精后2min,40℃处理2min,胚胎时期的三倍体诱导率达58%,孵化率为39%,幼鱼时期三倍体(含嵌合体)的检出率为40%,此条件为热休克处理的优化参数。正交分析得出,冷休克条件下起始休克时间是原肠期三倍化率和孵化率的重要影响因子,温度对畸形个体的产生有重要影响;热休克条件下,参考三倍体率、畸形率、孵化期相对存活率三者而言,休克温度均是重要因素。比较观察到冷休克处理组的胚胎受损情况严重,后期的成活率较热休克处理组要低,总体诱导效果逊于热休克处理组。     

茄子离体叶片光系统Ⅱ的冷激胁迫效应及热力学分析

 以耐冷性较强的短把黑圆茄和耐热性较强的黑帅圆茄为试材,经冷激胁迫后采用植物效率仪PEA,进行快速叶绿素荧光参数测定,并利用最大光化学效率Fv/F m和活性中心RC/CSo的标准状态变性自由能变△GD进行PSⅡ冷稳定性的热力学分析。随着冷激胁迫温度的降低和时间的延长,PSⅡ的Fv/Fm、实际光化学效率ΔF/Fm′、RC/CSo呈"S"型下降趋势;单位反应中心DIo/RC和非光化学猝灭qN呈"S"型上升趋势;综合分析反映出冷激胁迫下PSⅡ反应中心的可逆失活和依赖于叶黄素循环的热耗散的双重机制在保护PSⅡ防止光抑制中起到重要作用。另外,通过两品种间PSⅡ行为差异,引入了两组新的参数作为便于直观比较冷胁迫的评价指标。黑帅圆茄Fv/Fm、ΔF/Fm＇的半衰温度T1/2和t1/2值分别高于短把黑圆茄1.4 ℃和0.8 ℃。茄子叶片Fv/Fm和RC/CSo的△GD随着冷激胁迫温度的降低而减少呈瀑布型的下降趋势。黑帅圆茄的△GD值和变性中点温度Tm都低于短把黑圆茄。它们均反映出黑帅圆茄的耐冷性低于短把黑圆茄。     

Initiation and development of microspore embryogenesis in recalcitrant purple flowering stalk (Brassica campestris ssp. chinensis var. purpurea Hort.) genotypes

Purple flowering stalk (Brassica campestris ssp. chinensis var.purpurea Hort.) was generally regarded as a recalcitrant species for microspore culture in Brassica crops. Conditions for reliable induction of microspore embryogenesis were studied in 12 genotypes of purple flowering stalk. A treatment of short heat shock to microspore by incubating at 32 °C for 18 h was suitable for the survival of microspores, sustained cell divisions, and further induced embryogenesis. Subsequently, the reduced concentration of macro salts (1/2 NLN) provided an optimal condition for the development of embryoids. Under the optimized conditions for microspore embryoid development, 10 genotypes responded to microspore culture with the frequencies ranging from 2.7 to 70.5 embryoids per dish. However, regenerated plants were obtained from 9 genotypes, and more than 75% these regenerated plants were double haploid. This report establishes an efficient protocol for microspore culture and offers great potential for DH breeding in purple flowering stalk.     

不同贮前热处理对青种枇杷果实贮藏效应的研究

通过采用不同的贮前热处理温度和时间组合,研究白沙枇杷青种在低温条件下的贮藏的内外品质的变化.结果表明:3种贮前热处理中,B处理(45℃热水处理10 min+低温(6±1℃))的效果最好,不仅青种枇杷果实的失重率和腐烂率低;而且贮藏到30 d时,枇杷果实的固酸比最高,较好保持了果实的风味.     

汽车悬架阻尼匹配研究及减振器设计

为了使车辆满足平顺性要求,对车辆悬架系统阻尼匹配进行了研究,建立了最佳阻尼比设计方法及减振器速度特性分段线性数学模型.以此模型为基础,建立了减振器阎系参数设计数学模型,并对阀系参数进行优化设计.对设计减振器进行了特性试验和整车振动试验,并与原车裁减振器性能进行了对比.结果表明,车辆悬架系统阻尼匹配合理,减振器阀系参数设计方法正确,设计参数值准确、可靠.