The use of image analysis to study developmental variation in micropropagated potato (Solanum tuberosum L.) plants

Summary Potato leaf morphology changes during plant development with the phase shift from vegetative growth to flowering. Image analysis can detect differences in leaf morphology and has been used here to distinguish differences in leaf morphology between potato crops derived from seed tubers and minitubers and between crops derived from different micropropagation protocols. Further, leaf shape parameters can be used to determine the relative maturity of crops. This finding is of economic importance since differences in plant development, for example delayed flowering, are associated with yield parameters. It is hypothesised that image analysis of established microplants can be used as an early evaluation of micropropagation protocols for potato.     

Mutation breeding for yield andPhytophthora infestans (Mont.) de Bary foliar resistance in potato (Solanum tuberosum L. cv. Golden Wonder) using computerized image analysis in selection

Summary Using visual selection for off-types and image analysis to select against maturation mutants, a line combining improved late blight resistance and yield was isolated in an in vitro mutagenesis programme from a population of 2101 putative mutants. The adventitious regenerants from mutagenesis treatment, including spontaneous mutants (somaclonal variants), were subjected to serial subculture of the apical bud in vitro and two cycles of apical cuttings in vivo to breakdown chimeras. The selected line was stable in trials over five years; others were unstable or failed to combine improvement in late blight resistance with high yield. Leaf and tuber image analysis was used to characterize selected lines. Lines that differed most from cv. Golden Wonder in yield and late blight resistance were more easily distinguished from the control by image analysis. The role of image analysis in negative selection and in determination of the relatedness of mutants to the control is discussed.     

紫陀螺菌菌株的分离及鉴定

采用5种培养基配方,对紫陀螺菌子实体不同生长期的不同部位及菌根、菌索进行组织分离,结果从子实体得到的菌丝生长缓慢,菌丝致密,从菌根和菌索得到的菌丝生长快,絮状不致密。以紫陀螺菌干子实体DNA为参照样品,对得到的相关分离纯培养物进行亲菌鉴定。供试的26条随机引物中,有8条对所有供试样品可扩增出清晰、稳定的DNA指纹图谱,且从子实体分离得到的菌丝体DNA指纹与干子实体的基本一致。聚类分析结果表明,从子实体不同生长期得到的2个菌株相似系数0.979,它们与干子实体间的相似系数为0.884,从菌根和菌索得到的分离物与干子实体间的相似系数为0.389。结果表明,从子实体分离得到的2个菌株与对照物相似度最高,可以认定是紫陀螺菌的纯培养物。     

凡纳滨对虾ARMC8基因的克隆及表达

为了研究含Armadillo重复蛋白8在凡纳滨对虾抗病感染过程中所起的免疫作用,本实验采用RACE-PCR技术首次克隆得到凡纳滨对虾ARMC8基因(LvARMC8,Gen Bank注册号:KX058562)的c DNA序列全长,并利用在线软件进行生物信息学分析;采用实时荧光定量PCR(Rt-PCR)技术对LvARMC8基因在凡纳滨对虾不同组织及感染白斑综合征病毒和副溶血弧菌过程中的表达变化特征进行分析。结果显示,LvARMC8基因全长为2917bp,其中开放阅读框长2046 bp,编码681个氨基酸,5′非编码区长49 bp,3′非编码区长822 bp。预测分析显示LvARMC8编码的蛋白质含有6个ARM结构域。同源性分析发现,LvARMC8基因与内华达古白蚁ARMC8基因的相似度最高,为71%。系统进化分析结果显示,LvARMC8和多种无脊椎动物ARMC8聚为一支,其中与昆虫类动物赤拟谷盗、致倦库蚊和柑橘凤蝶的亲缘关系最近。Rt-PCR分析发现,LvARMC8基因在凡纳滨对虾多个组织中均能检测出,在表皮中表达量最高,眼柄中表达量最低。WSSV感染后12 h,LvARMC8基因在凡纳滨对虾血液中的表达量显著降低,但48 h后显著升高,72 h达到最高水平。除副溶血弧菌感染后24 h外的时间点,LvARMC8基因在凡纳滨对虾血液中的表达量均显著升高。研究表明,LvARMC8基因可能参与凡纳滨对虾抗病免疫应答途径。     

大黄鱼冷诱导结合蛋白(CIRP)基因cDNA克隆及低温胁迫对其时空表达的影响

为研究冷诱导结合蛋白(CIRP)在大黄鱼低温适应过程中的作用,采用同源克隆技术获得了大黄鱼CIRP基因,并通过实时荧光定量PCR(qRT-PCR)技术检测了低温胁迫下大黄鱼各组织中CIRP基因的表达变化。结果显示,大黄鱼CIRP基因cDNA序列全长1211 bp,推测编码一个由182个氨基酸组成、分子量为19 ku的蛋白。序列比对显示硬骨鱼类CIRP基因序列较为保守,特别是N端的RNA识别基序(RRM)高度保守。系统进化树分析显示大黄鱼CIRP与银鳕相似性最高(81.5%),所有硬骨鱼类聚为一个大支。慢性低温胁迫中(12℃缓降至6℃),皮肤和肌肉中CIRP基因的表达量呈随温度降低而升高的趋势,6℃时表达量分别为12℃时的11.56倍和9.03倍;鳃、脑和心脏中CIRP基因表达量均呈先显著上升后显著下降的趋势,其峰值均出现在8℃时,表达量分别为12℃时的5.07、7.69和2.83倍;肠、肾脏、肝脏和脾脏中的表达量随温度降低而下降,6℃时的表达量最低,与12℃时相比降幅分别为80.0%、65.6%、91.2%、55.6%。急性低温胁迫(由12℃骤降至8℃并胁迫4 h)条件下,鳃、皮肤、脑、肝脏、心脏中CIRP基因表达量均呈先升高后降低的变化,反映了机体对低温胁迫的应激、适应过程;肌肉和肠中的表达量则始终显著低于胁迫前。慢性和急性低温胁迫中各组织CIRP表达量变化的差异提示,大黄鱼机体在低温胁迫响应和适应中有着多种调节机制。研究表明,CIRP基因参与了大黄鱼应对低温胁迫的过程。     

银鲳不同组织中4种同工酶的表达差异

采用聚丙烯酰胺凝胶电泳技术,分析了银鲳(Pampus argenteus)脾脏、肝脏、肌肉、心脏、肾脏等5种组织中酯酶(EST)、乳酸脱氢酶(LDH)、谷氨酸脱氢酶(GDH)、乙醇脱氢酶(ADH)等4种同工酶的表达模式,并对各种同工酶的酶谱进行了分析。结果表明:这4种同工酶在银鲳5种组织中的分布均存在一定的组织特异性,其与各组织的生理机能密切相关。银鲳4种同工酶共记录出61条酶带,其中EST被检测出的酶带数量最多也较复杂,ADH同工酶酶带数量最少,只有6条酶带被检测到,LDH和GDH分别检测到16条和9条酶带;组织特异性主要表现在位点表达和酶活性强弱不同这两个方面,GDH1和ADH2只在肝脏中表达。     

养殖大鳞鲃发病死亡F_3个体的微卫星标记分析

采用24个已报道的多态微卫星标记对天津市天祥水产有限责任公司养殖的大鳞鲃Barbus capito F_2亲本及F_3成活和病发死亡个体进行基因分型,结果有8个标记无多态,13个标记用以分析本研究群体的遗传多样性、亲缘关系及遗传结构。遗传参数分析显示,13个标记在87个大鳞鲃个体中分别检测到2~7个等位基因,平均等位基因数(4.27~4.53)极显著高于平均有效等位基因数(3.09~3.22)(P0.01);观察杂合度(0.58~0.64)整体低于期望杂合度(0.64~0.65),多态位点比例明显下降(8/24),表明大鳞鲃F2及F_3个体的纯合度增加,遗传多样性下降。聚类分析显示,F2亲本与成活子代亲缘关系更近,聚在一起;而死亡子代单独聚为1支。遗传结构分析显示,亲本与子代清晰地划分成两大类群,多数亲本与多数成活个体归为第一类群(划分概率为51.8%~97.7%),少数亲本与多数死亡个体归为第二类群(划分概率为52.9%~98.4%),这与亲缘关系分析的结果一致,表明少数亲本是F_3死亡个体遗传组成的直接贡献者。本研究初步认定,由于几个亲本的近亲交配,子代基因组纯合度增加,遗传多样性下降,抗逆性下降,这可能是F_3出现不明缘由病发死亡的主要原因之一。     

Liver histology and histomorphometry in hybrid sorubim (Pseudoplatystoma reticulatum × Pseudoplatystoma corruscans) reared on intensive fish farming

This study aimed to characterize the liver histology and histomorphometry in sorubim hybrid of different categories (nursery, growth and grow‐out) reared on fish farming. The categories were defined considering body weight (BW): nursery category (n = 5): BW = 37.06 ± 6.00 g (31.6–45.3 g); growth category (n = 5): BW = 310.40 ± 53.80 g (242.1–376.4 g) and grow‐out category (n = 5): BW = 874.28 ± 27.59 g (846.2–913.1 g). Liver fragments were processed to paraffin inclusion, and sections were stained by haematoxylin and eosin (H&E), PAS (Periodic Acid Schiff) and Perl's staining to histology, histomorphometry and density volumetric of liver structures; glycogen analysis and to detect ferric irons (Fe³⁺) respectively. The hepatosomatic index decreased between the categories (P < 0.01). The percentage of PAS‐positive hepatocytes in the nursery category was higher (P < 0.05) in relation to the growth and grow‐out categories. The hepatocytes from all fish were positive to Perl's staining. The density volumetric of liver structures did not differ among categories except to blood vessels were higher (P < 0.01) in the nursery and growth. The area (μm²) and perimeter (μm) of hepatocytes, and the area (μm²), perimeter (μm) and volume (μm³) of the nuclei from grow‐out fish were lower (P < 0.01) than those from the nursery and growth categories. Changes in morphometric characteristics of hepatocytes may result from metabolic changes associated with body growth surubins; therefore, these morphometric characteristics of liver tissue can be used as functional biomarkers for the assessment of fish health and nutrition status.     

急性操作胁迫对四指马鲅幼鱼肝脏组织结构和氧化应激的影响

为探究急性操作胁迫对四指马鲅(Eleutheronema tetradactylum)幼鱼肝脏组织结构以及氧化应激的影响,该研究在离水操作胁迫后不同时间取样,观察肝脏显微结构的变化,并检测相关抗氧化酶活性。结果显示,随着离水胁迫时间的延长,肝脏组织损伤程度呈现先上升后下降的趋势,胁迫第24小时肝脏基本结构与对照组相似。超氧化物歧化酶(SOD)和过氧化氢酶(CAT)有相同的变化趋势,胁迫后第2小时显著增加(P0.05)并达到最高值,然后开始下降,最后其值显著低于对照组(P0.05);丙二醛(MDA)含量在胁迫第2~第12小时呈现先升高后下降的变化趋势,第12小时后又有所上升;还原型谷胱甘肽(GSH)含量胁迫2 h没有显著变化(P0.05),之后呈先下降后上升的趋势,但其含量仍显著低于对照组(P0.05);总抗氧化能力(T-AOC)胁迫第2小时显著上升(P0.05),之后下降,实验结束时显著低于对照组(P0.05)。结果表明离水操作胁迫对四指马鲅幼鱼肝脏组织结构以及抗氧化酶产生一定的影响,但随着胁迫时间的延长,其组织结构以及抗氧化能力都有一定的恢复趋势。     

硼中毒对固始鸡生长性能及胸腺发育的影响

120只 1日龄固始鸡随机分为 2组, 试验组在饮水中添加 400mg·L-1硼。每周每组取鸡 10只, 颈静脉放血致死,取胸腺, 称重, 制作石蜡切片, 光镜观察。实验结果表明: (1 ) 试验组胸腺重及胸腺 /体重比显著低于同周龄对照组(P<0 05), 3、5、6周龄胸腺重及 1、2、3、5周龄胸腺 /体重比极显著低于对照组 (P<0 01); (2) 试验组 1、2周龄鸡胸腺明显萎缩, 间质显著增多, 实质急剧退化, 胸腺细胞急剧减少或空竭, 胸腺小体增多、增大; (3) 3周龄起, 试验组大多鸡胸腺发育呈恢复状态, 6周龄, 胸腺组织结构基本恢复。以上结果提示, 添加 400mg·L-1硼的饮水对固始鸡的生长与胸腺的发育, 尤其是胸腺早期发育, 有明显抑制和毒性作用。