Application of bioelectrical impedance analysis as a method for estimating composition and metabolic condition of southern bluefin tuna (Thunnus maccoyii) during conventional tagging

Tagging fish without gathering physiological information may be a wasted opportunity. We tested bioelectrical impedance analysis (BIA) for measurement of relative condition of southern bluefin tuna (Thunnus maccoyii) during conventional tagging at sea. We refined the equipment and method by measurement of 360 fish during conventional and acoustic tagging. Our results demonstrate that BIA is an accurate measure of condition for southern bluefin tuna in the same way it has been shown to be for metabolic condition and composition in other vertebrates including humans. Further, there is sufficient variation in BIA measures of the natural population to give meaningful measures of both metabolic condition and composition between groups at different times and developmental stages. Condition of tuna in this study may be related to the ocean environment just prior to measurement. BIA meets the necessary objectives for measuring fish condition during tagging as it is shown to be harmless, reliable, quick, and effective and does not disrupt conventional tagging operations. In the light of these results this type of condition measurement should be taken wherever possible in future tagging operations for this and other similar species, which will generate new insight into the ecological challenges faced by pelagic fishes. The ability to relate recent ocean environments and subsequent patterns in fish survival may lead to changes in the way tagging data is interpreted.     

Development of a large population of activation-tagged mutants in an elite indica rice variety

In this study, we have generated more than 12,000 activation-tagged mutants in a high-yielding indica rice variety, 'BPT 5204', employing maize Ac/Ds system. Different transgenic plants obtained were analysed based on expression patterns of green fluorescence protein (GFP), red fluorescence protein (RFP), herbicide (Basta) tolerance and molecular analyses. T₁ seeds of pSQ5 and pSQ5-bar transgenics, when germinated separately on hygromycin (50 mg/L) and phosphinothricin (5 mg/L) containing medium, revealed a segregation of 3 tolerant : 1 susceptible plants. The germinal transposition frequency of Ds element in different T₂ progeny of rice plants was found to be about 18.0%. Different stable tagged mutants exhibited marked increases in plant height, number of tillers, leaf size, panicle size, seed size and number of grains per plant. The overall results indicate that the genes associated with these traits are upregulated by the enhancer element in activation-tagged mutants. As such, the various tagged mutant lines appear promising and serve as a valuable genetic resource for identification of key genes determining different agronomic traits of rice.     

Mu转座子介导的玉米插入突变体的鉴定

选取5个对干旱胁迫响应的玉米蛋白磷酸酶基因,从Mu突变体库中定向筛选到这些基因共92个Mu转座子插入的候选突变体.在田间种植这些候选突变体的后代,每个12粒.利用巢式PCR对这些后代植株的目标插入位点进行鉴定,选择阳性植株与B73杂交或回交.在92个候选突变体中,有21个为可遗传的Mu转座子插入突变体;其中8个突变体的...     

Biosurfactants produced by Pseudomonas fluorescens and soft-rotting of harvested florets of broccoli and cauliflower

Mini-Tn5 transposon mutagenesis of a soft-rotting isolate of Pseudomonas fluorescens strain 123 produced six mutant phenotypes with altered pathogenicity and inability to produce a biosurfactant involved in dispersing P. fluorescens cells in a surface aqueous environment. The mutants isolated showed in vivo growth characteristics identical to those of the wild type, but variations in their ability to reduce surface tension of water and to grow in liquid medium containing hexadecane. One of these mutants (EG3) with reduced pathogenicity on broccoli and cauliflower exhibited a restored pathogenic phenotype when complemented with a 7·1-kb segment of P . fluorescens genomic DNA. The loss of aqueous-surface-tension activity in mutants suggests that a biosurfactant may contribute to pathogenicity and enhance pathogen invasion of host tissues.     

Deformity of agglutinated pelvic fin membrane in hatchery-reared black rockfish Sebastes inermis and its application for stock separation study

ABSTRACT:   This study is the first to report on the high occurrence of agglutinated pelvic fin membrane deformities in hatchery-reared black rockfish Sebastes inermis . For 5 years, this symptom was marked in hatchery-reared fish, with 58.7% of fish deformed on average (varying between 46.7 and 72.0%). The deformity was a peculiarity in hatchery-reared fish, but is negated in wild fish, and was not related to whether the fish broodstock originated from the wild or from a hatchery. Mark–release experiments showed that deformed fish were almost the same as normal hatchery-reared fish in growth and survival rates, and, theoretically, the recapture numbers of hatchery-stocked fish, estimated by deformity, almost coincided with actual recapture numbers, confirmed by otolith tagging. The results of the present study indicate that deformity in hatchery-reared black rockfish is useful as a stock separation tool.     

小麦赤霉病抗源望水白的QTL定位

236对SSR引物中共有74对在小麦（Tritium aestivum）抗、感亲本之间有多态性,多态性频率达31.7%.对小麦望水白/安农8455群体的SSR分析表明,在2年资料中都出现的与抗小麦赤霉病（Fusarium head blight）连锁的SSR标记有14个,主要分布在染色体3B和2A上.利用Map Manager QTX软件构建连锁图和QTL定位,有38个标记主要分布于5条染色体上（3B、2A、5A、6B和7B）;根据3年的抗性资料分析,3B上的QTL分别位于XBarc133～Xgwm389、XBarc133～Xgwm389和Xg-wm533.1～Xgwm493之间,LOD为2.58、6.49和2.45,分别能解释10%、23%和9%的表型变异.2001年和2003年的抗性资料分析表明,2A上存在2个抗性QTL,都位于Xgwm95～Xgwm372之间,LOD分别为2.82和2.93,均能解释11%的表型变异.     

Nodulation and competitiveness of gusA-marked Bradyrhizobium japonicum A1017 in soybean

Attempts to improve the symbiotic nitrogen fixation with effective (Brady) rhizobium strains do not always succeed under field conditions due to the lower nodulation competitiveness of the introduced strains than that of the indigenous rhizobia (Triplett and Sadowsky 1992). An introduced strain needs to be marked for monitoring its nodule occupancy under competitive nodulation conditions.     

Towards the isolation of resistance genes by transposon targeting in potato

A general strategy for the isolation of disease resistance genes is presented, employing a two-step approach of transposon targeting near genes of interest followed by transposon tagging. A library of transposon (Ac/Ds) transformants in a self fertile potato diploid are being mapped by deriving genomic DNA probes flanking the transposon containing T-DNA insertions with the inverse polymerase chain reaction and using these probes for RFLP analysis. We have produced a large number of transposon (Ac/Ds) transformants in a self fertile potato diploid. Genomic DNA probes, flanking the transposon containing T-DNA insertions, are produced by the inverse polymerase chain reaction (IPCR) and mapped by restriction fragment length polymorphism (RFLP) analysis in a segragating potato location. A transposon mapped close to a resistance gene can be recombined cis to the gene and used for efficient transposon targeting due to preferential transposition to linked sites.     

应用DNA标记定位水稻的抗稻瘟病基因

 从水稻分子遗传图谱选取177个RFLP标记,比较以红脚占为抗源,感病品种IR24为轮回亲本所构建的近等基因对K80R和K79S之间的多态性表现。发现了一些可能与稻瘟病抗性基因连锁的阳性标记。在(K80R×K79S)的F₂群体中,经稻瘟病菌ZB₁小种接种,110株为抗病,33株为感病,用总共10个阳性标记与F₂群体中每个单株的DNA杂交,发现抗病基因与第12染色体上的标记RG81、RG869和RZ397共分离;检测F₃株系的抗病性分离情况,确定F₂植株的抗病性基因型,计算出抗病基因与分子标记的遗传距离,将该基因定位在第12连锁群上。应用近等基因池DNA和随机引物,经PCR扩增和共分离分析,建立了二个RAPD片段与抗病基因紧密连锁。     

Isolation and Characterization of a New Virulence Gene (abvA) of Agrobacterium tumefaciens

A mutant (M-1) was isolated by transposon (Tn5) insertion mutagenesis of Agrobacterium tumefaciens (strain A-208, C58 chromosome, nopaline type T37 pTi, virulent). The M-1 mutant exhibited a complete avirulent phenotype on Kalanchoe daigremontiana leaf and Kalanchoe pinnata stem but a very attenuated virulent phenotype on root of Daucus carota. The mutant had one insertion of Tn5 in pTi. A wild-type target segment (2.3 kb) that included the site of Tn5 insertion in M-1 mutant was cloned. Introducing the 2.3 kb segment into M-1 complemented completely the avirulent phenotype, producing galls as big as strain A-208. The 2.3 kb segment was sequenced, identifying three open reading frames, ORF 1 (354 bp), ORF 2 (261 bp) and ORF 3 (801 bp) in the segment. A Tn5 was inserted between the third and fourth nucleotide of ORF 1 in M-1. The ORF 1 had no homology to any reported genes and thus was named the abvA gene. The ORF 3 had the high homology (identities 44%, positive 68%) to the gene of the sarcosine oxidase β subunit (accession no. sp/P40875). Introduction of the DNA segment (743 bp) containing the abvA gene and its promoter region into M-1 partially complemented the avirulent phenotype of the mutant, producing galls smaller than strain A-208. The abvA gene was distributed not only on nopaline-type pTi (T37) but also on octopine-type pTi (A6NC) and chromosome (C58) of A. tumefaciens. M-1, being avirulent on K. daigremontiana and K. pinnata, had a Tn5 insertion only in the abvA gene on pTi but not in the abvA gene on the chromosome, implying that the abvA gene on the chromosome in strain A-208 is not functional. A binary vector, pIG121-Hm, containing the β -glucuronidase (GUS) gene with an intron was introduced into M-1, which was then applied to leaves of K. daigremontiana to assay GUS activity for monitoring T-DNA transfer to the host nucleus. High GUS activity comparable to that in strain A-208 was detected in M-1 in spite of its inability to induce galls, suggesting that M-1 can transfer T-DNA into the host nucleus, but cannot integrate it into the chromosome. Received 25 October 2000/ Accepted in revised form 28 December 2000