Simultaneous estimation of instantaneous mortality coefficients and rate of effective survivors to number of released fish using multiple sets of tagging experiments

ABSTRACT:   A method is proposed for estimating two instantaneous mortality coefficients, and rate of effective survivors to number of tagged fish released, using exact times at liberty from multiple sets of tagging experiments. Effective survivors are defined here by the product of survivors immediately after releasing and reporting rate of recaptures. A least-squares method was applied to estimate the parameters using statistical models expressing the numbers of effective survivors, which were calculated by a principle similar to virtual population analysis. In order to investigate the statistical performance of the method, simulation trials using operating models were carried out. The method was applied to data of tagging experiments for alfonsino Beryx splendens from 1957 to 1969, off Kanagawa Prefecture. In most of the results of simulation trials, the method yielded estimates of natural mortality coefficient of which expected values were within ± 12% of true values. Estimates of natural mortality coefficient, fishing coefficient and the rate of effective survivors for alfonsino are 0.57 (per year, 95% confidence limits [CL] 0.40–0.69), 0.094 (per year, 0.03–0.25) and 0.39 (0.12–1.00), respectively. Modifications for the generalization of the method and notes on its applications are discussed.     

Molecular tagging of a gene for resistance to brown planthopper in rice (Oryza sativa L.)

An introgression line derived from an interspecific cross between Oryzasativa and Oryza officinalis, IR54741-3-21-22 was found to beresistant to an Indian biotype of brown planthopper (BPH). Genetic analysisof 95 F₃ progeny rows of a cross between the resistant lineIR54741-3-21-22 and a BPH susceptible line revealed that resistance wascontrolled by a single dominant gene. A comprehensive RAPD analysisusing 275 decamer primers revealed a low level of (7.1%) polymorphismbetween the parents.RAPD polymorphisms were either co-dominant (6.9%), dominant forresistant parental fragments (9.1%) or dominant for susceptible parentalfragments (11.6%). Of the 19 co-dominant markers, one primer,OPA16, amplified a resistant parental band in the resistant bulk and asusceptible parental band in the susceptible bulk by bulked segregantanalysis. RAPD analysis of individual F₂ plants with the primerOPA16 showed marker-phenotype co-segregation for all, with only onerecombinant being identified. The linkage between the RAPD markerOPA16₉₃₈ and the BPH resistance gene was 0.52 cM in couplingphase. The 938 bp RAPD amplicon was cloned and used as a probe on122 Cla I digested doubled haploid (DH) plants from aIR64xAzucena mapping population for RFLP inheritance analysis and wasmapped onto rice chromosome 11. The OPA16₉₃₈ RAPD markercould be used in a cost effective way for marker-assisted selection of BPHresistant rice genotypes in rice breeding programs.     

猕猴桃溃疡病菌不致病菌株G230的鉴定及形成原因分析

为探索田间猕猴桃溃疡病菌Pseudomonas syringae pv. actinidiae(Psa)致病力丧失的分子机制,针对从猕猴桃果园中分离获得的1株不致病菌株G230,通过特异性引物检测和多基因序列分析明确其分类地位,并设计引物检测其是否由已知遗传变异引起,通过比较基因组学、基因表达、超敏反应和荧光素酶报告菌株检测确定引起菌株G230致病力丧失的原因。结果表明,不致病菌株G230为Psa生物型3(Psa3),其致病缺陷不是由已报道的遗传变异引起;基于基因组比较分析发现菌株G230中的hrpS基因被转座子ISPsy36插入破坏,导致Ⅲ型分泌系统（type Ⅲ secretion system,T3SS）不能正常表达;而在不致病菌株G230中表达hrpS基因后能恢复其T3SS功能,使其具备致病能力及激发非寄主超敏反应的能力。表明转座子ISPsy36插入hrpS基因内部可以破坏Psa的T3SS功能进而使其丧失致病力,这是自然条件下Psa3丧失致病力的一种新型机制。     

基因克隆技术

综述了基因克隆常用技术包括图位克隆法、转座子或T－DNA标签法、同源序列法、表达序列标签（EST）法和差异表达基因分离方法的原理、应用、应用的潜力和限制因素。     

玉米Mutator转座子

Mutator转座子因其拷贝数高、正向突变频率高、倾向于插入低拷贝的DNA序列等独特的遗传特性,已成为基因组学研究中重要的诱变剂之一。本文对Mutator转座子的发现、Mutator家族的分类、Mutator转座子的特性、Mutator元件的表观调控、Mutator转座子标签在植物基因组学研究中的应用作了综述。对Mutator系统的研究进行了展望。     

睡美人转座子真核表达载体的构建及在猪胎儿成纤维细胞系中的表达验证

睡美人(sleeping beauty,SB)是Tc1/mariner转座子超家族的一员,为探索睡美人转座子与不同的转座酶搭配使用及与同种转座酶不同比例搭配使用时的转座效率,本实验构建了SB真核表达重组载体PT2-SV40-EGFP,通过荧光显微镜和实时荧光定量PCR(qRT-PCR)检测进行了猪胎儿成纤维细胞系(PEFs)转染条件优化研究.研究结果表明,不同转座酶与转座子按10∶1混合后细胞转染效率相似,但报告基因表达水平有较大差异,其中SB 100X转座酶与转座子混合后细胞的表达水平最高;转座子PT2-SV40-EGFP质粒和SB 100X转座酶质粒按不同比例混合转染细胞研究表明,细胞转染效率相似,但表达水平存在显著差异,其中1∶1组最高,约是5∶1组和10∶1组的50倍.本实验优化了睡美人转座子的转座条件为制备转基因动物深入研究提供参考.     

Biology of Larks (Aves: Alaudidae) in the Central Namib Desert

1. The biology of six species of larks in the Namib Desert near Walvis Bay, South West Africa, was studied in 1964, 1965 and 1966.

2. All species reproduced following rainfall in summer and autumn months, with the appearance of green grass and abundant insects on which the birds fed.

3. The primarily insectivorous species, Certhilauda albofasciata, shows no seasonality in moulting and testicular development, and reproduces whenever local rainfall results in favourable feeding and nesting circumstances, while the primarily granivorous Spizoeorys starki and Eremopterix verticalis have markedly seasonal testicular and moulting cycles timed so that reproduction occurs only during the late summer and autumn months. Ammomanes grayi is intermediate in food habits and in timing of moulting and reproduction, and C. albescens and Mirafra naevia may also be intermediate in this respect.

4. S. starki and E. verticalis are the only larks that normally drink, but flocks of both species were observed that were independent of drinking water.

5. Larks avoid heat stress during daytime by keeping to the shade of stones, tufts of vegetation and mouths of rodent burrows; and nests are nearly always placed on the shady side of a stone' or tuft of grass.

6. It is suggested that larks may be successful desert occupants because they have not become highly specialized and therefore can tolerate rapidly and severely changing environ-mental conditions associated with drought and irregular rainfall.     

鸡源沙门氏菌对β-内酰胺类抗生素耐药相关基因的筛选及鉴定

[目的]从沙门氏菌全基因组范围筛选和鉴定其与β-内酰胺类抗生素耐药性相关的基因.[方法]对临床分离的10株沙门氏菌进行药敏试验,选择耐药性最广泛的菌株作为研究对象,利用mariner转座子对其基因组进行随机突变,获得转座子突变株文库,筛选文库中对β-内酰胺类抗生素敏感的突变体,通过套式PCR、核苷酸测序及序列比对确定突变体中转座子的插入位点及其破坏的基因.[结果]从突变株文库中筛选得到15株分别对青霉素G、氨苄西林和头孢哌酮敏感的突变株,其中3株对三种抗生素都敏感.转座子破坏基因为STM4216 (inner membrane protein)和STM4150 (50S ribosomal protein L1).[结论]筛选出的基因有望成为控制或扭转沙门氏菌耐药性的作用靶点.     

利用与su1紧密连锁的Ac转座子构建玉米插入突变体库

以位于玉米第4号染色体短臂与su1紧密连锁的Ac转座子作为Ac供体,结合w22报道系,创建1 507个Ac远距离转座事件。利用基于Southern Blot的IPCR和基于酶切连接的Genome-Walking PCR方法,分离到其中56个独立的可遗传Ac/Ds(transposed Ac/Ds,tr-Ac/Ds)侧翼序列标签,补充了Ac/Ds转座插入突变体的数量。利用玉米B73的基因组序列,通过BLAST比对分析将trAc/Ds定位到了玉米基因组上,并分析了Ac/Ds插入位点附近DNA序列,其中51个tr-Ac/Ds插入序列为单拷贝序列,鉴定到39个trAc/Ds插入到了基因内部,12个Ac/Ds插入到基因间区域,进一步证明了Ac/Ds倾向于插入基因内部和低拷贝的基因组富集区。     

Tracking bluefin tuna reproductive migration into the Mediterranean Sea with electronic pop‐up satellite archival tags using two tagging procedures

Thirteen adult bluefin tuna were tracked with electronic pop‐up satellite tags during their reproductive migration towards Mediterranean spawning grounds as they entered the Strait of Gibraltar. Fish were caught in tuna traps and tagged either underwater, with the aid of a modified spear gun, or on the deck of the boat. Fish tagged on board initially showed a shallower behavior than those tagged in the water. The pattern of horizontal movements was also different between both groups. Shortly after tagging, the eight fish tagged in the water entered the Mediterranean Sea. Six of these fish reached the spawning ground located southwest of the Balearic archipelago before heading back for the Atlantic, whereas the other two traveled farther east, reaching its easternmost longitudes between Formentera and Sardinia and the South Tyrrhenian Sea, respectively. In contrast, two out of the five fish tagged on board never entered the Mediterranean Sea, and another one did enter the Mediterranean when the reproductive season was already over. These results suggest an impact of the tagging procedure on the post‐release behavior of bluefin tuna. Excluding the tags that popped‐off east of the Strait of Gibraltar, bluefin tuna stayed in the Mediterranean Sea for 22–28 days. Analysis of the median depth indicated a shallow behavior during both day and nighttime throughout the return phase of the fish from the Mediterranean Sea to the Atlantic Ocean with the exception of the area around the Strait of Gibraltar, where they showed a deeper behavior that coincided with a marked vertical gradient in the currents.