Microsatellite primers for the Atlantic coastal killifish,Fundulus heteroclitus,with applicability to related Fundulus species

The mummichog (Fundulus heteroclitus), a common Atlantic coastal killifish, is a model vertebrate species for the study of molecular genetic variation in natural populations and of environmental toxicology. We report the development of a set of 20 microsatellite loci in this species. Average expected heterozygosity across all loci was 0.84 (range: 0.60–0.97), revealing a high level of variability at most loci. A survey of seven additional Fundulus species yielded one or two robust amplification products in over half (63%) of the species–primer combinations tested. Therefore, many of these loci will also prove useful in studies of other members of the genus Fundulus.     

THE CYTOSKELETON OF THE NAKED GREEN FLAGELLATE SPERMATOZOPSZS SIMILIS (CHLOROPHYTA): ANALYSIS OF ISOLATED BASAL APPARATUSES IN THE PARALLEL CONFIGURATION1,2

The biflagellate green alga Spermatozopsis similis is demonstrated to be a model organism for the biochemical and functional analysis of the basal apparatus. Basal apparatuses were isolated in the presence of 10⁻⁶ M Ca²⁺, which induces the reorientation of the basal bodies into the parallel state. Serial thin sectioning of enriched basal apparatuses stained with tannic acid reveals several novel details of the structure of the basal bodies, the distal connecting fiber, and the striated microtubule-associated fibers. We observed a pronounced difference in size of a striated fiber connecting the basal bodies to the five-stranded microtubular roots depending on its association with the developmentally older or younger basal body. Instead of a proximal connecting fiber, the proximal end of each basal body is associated with a striated triangular plate; these plates appear to serve as spacers for the basal bodies in the parallel and antiparallel configurations. We suggest that the plates play a role in maintaining basal body orientation during forward and backward swimming. The results are summarized in representative drawings of the basal apparatus.     

A review of the genus Malakichthys Döderlein (Perciformes: Acropomatidae) with the description of a new species

Malakichthys Döderlein, 1883, comprises seven species: type species Malakichthys griseus Döderlein 1883, from southern Japan to north‐western Australia; Malakichthys barbatus Yamanoue & Yoseda, 2001 , from southern Japan, the South China Sea, north‐western Australia and the Coral Sea; Malakichthys elegans Matsubara & Yamaguti, 1943 , from southern Japan south to the Arafura Sea; Malakichthys levis Yamanoue & Matsuura, 2001 , from northern Australia; Malakichthys mochizuki Yamanoue & Matsuura, 2001 , from the Coral Sea; Malakichthys similis sp. nov. from the Bohol Sea, Philippines; Malakichthys wakiyae Jordan & Hubbs, 1925 , from southern Japan and Taiwan. Species of Malakichthys are very similar to each other in general appearance but are distinguishable by spination on the lower jaw, features of the proximal‐middle radial of the first anal‐fin pterygiophore, the number of anal‐fin soft rays and body depth.     

似士维螨对西洋参根的取食量及其繁殖潜势

【目的】作为西洋参Panax quinquefolium L.的新害虫,似士维螨Schwiebea similis Manson蛀食参根,造成较大的经济损失。本研究旨在测定它对参根的取食量,进而为估算其经济阈值提供参数。【方法】本实验将似士维螨活雌螨接种于含湿沙和西洋参根粉的培养皿中塑料环内,在7级雌螨接种量N_0(每环1,2,3,4,5,6和7♀)和5个温阶T(15.6,18.5,21.2,24.5和27.2℃)条件下培养其实验种群,记载并分析了5类变量:安居期D、峰螨数N_p、雌均殖数PCR、成虫当量AE和均食量FA。【结果】变量D随T升高而快速下降,也因N_0增加而缓慢下降;N_p随N_0增加而显著上升,其回归式为N_p=21.8+17.2N_0;PCR随N_0增加而显著下降,PCR=63.4-28.1N_0+6.2N_0~2-0.4N_0~3,其曲线变化趋势与N_p相反;同时发现了螨虫拥挤效应;AE随N_0增加而显著上升,AE=16.2+12.7N_0;FA=0.25±0.13 mg/头。【结论】这5类变量较为全面地反映了似士维螨实验种群的食量范围和繁殖潜势。上述估算值将为探索其经济阈值提供依据;所用实验方法将为同类研究提供参考。     

Influence of Mycorrhizal Fungus, Phosphorus,and Burrowing Nematode Interactions on Growth of Rough Lemon Citrus Seedlings

Rough lemon seedlings were grown in mycorrhizal-infested or phosphorus-amended soil (25 and 300 mg P/kg) in greenhouse experiments. Plants Were inoculated with the citrus burrowing nematode, Radopholus citrophilus (0, 50, 100, or 200 nematodes per pot). Six months later, mycorrhizal plants and nonmycorrhizal, high-P plants had larger shoot and root weights than did non-mycorrhizal, low-P plants. Burrowing nematode population densities were lower in roots of mycorrhizal or nonmycorrhizal, high-P plants than in roots of nonmycorrhizal, low-P plants; however, differences in plant growth between mycorrhizal and nonmycorrhizal plants were not significant with respect to initial nematode inoculum densities. Phosphorus content in leaf tissue was significantly greater in mycorrhizal and nonmycorrhizal, high-P plants compared with nonmycorrhizal, low-P plants. Nutrient concentrations of K, Mg, and Zn were unaffected by nematode parasitism, whereas P, Ca, Fe, and Mn were less in nematode-infected plants. Enhanced growth associated with root colonization by the mycorrhizal fungus appeared to result from improved P nutrition and not antagonism between the fungus and the nematode.     

Characterization of a New Burrowing Nematode Population,Radopholus citrophilus,from Hawaii

Karyotype, host preference, isozyzme patterns, morphometrics, and mating behavior of two burrowing nematode populations from Hawaii, one infecting Anthurium sp. and the second infecting Musa sp., were compared with Radopholus similis and R. citrophilus populations from Florida. The population from Anthurium sp. had five chromosomes (n = 5), and that from Musa sp. had four (n = 4). Neither of the Hawaiian nematode populations persisted in roots of Citrus limon or C. aurantium. Anthurium clarinerivum and A. hookeri were hosts of the burrowing nematode population from anthurium in Hawaii and of R. citrophilus from Florida, whereas the two anthurium species were poor hosts of the population from Musa sp. in Hawaii and R. similis from Florida. The isozyme pattern of the population isolated from anthurium was identical to that of R. citrophigus, whereas the pattern of the population from banana in Hawaii was identical to that of R. similis. Mating behavior between the burrowing nematode population isolated from Anthurium sp. and a Florida population of R. citrophilus supports their close taxonomic relationship. Mating was observed between the population from Anthurium sp. and the Florida population of R. citrophilus but not between the Hawaiian burrowing nematode population isolated from Musa sp. and a Florida population of R. citrophilus. These findings indicate that a previously unidentified population of R. citrophilus which does not parasitize citrus occurs in Hawaii.     

Nematicidal Effects of Oxamyl Applied to Leaves of Banana Seedlings

Foliar applications of oxamyl prevented nematodes from invading roots of diploid bananas. One spray with 1,250 μg/ml was more effective than 1, 2, or 3 sprays with 625 μg/ml applied at 5-day intervals. After 3 sprays with 1,250 μg/ml, invasion may be prevented for up to 4 weeks and possibly longer. Washing roots after oxamyl treatments prevented nematicidal control. When applied to nematode-infected plants, three sprays of oxamyl decreased nematode populations in the roots.     

Relationships between nematodes, weevils, banana and plantain cultivars and damage

Infestation of banana and plantain suckers by nematodes (Pratylenchus good-eyi, Radopholus similis and Helicotylenchus multicinctus) and weevils (Cosmopolites sordidus) increased with time from establishment in a field of eight different cultivars. There was a strong association between nematode and weevil infestation; suckers infested with nematodes were more than four times more likely to be infected by weevil than suckers without nematodes. Weevil damage, measured by percentage coefficient of infestation (PCI) at harvest of the bunch, was higher on a plantain (cv. Gonja) and on an east African highland cooking banana (cv. Lusumba) than on the sweet and multi-purpose cultivars. There was a correlation between numbers of male weevils caught in a plot and the mean PCI measured in the plot, but no correlation with female numbers.     

五种线虫头端顶面的扫描电镜观察

应用扫描电镜观察了弗氏旷口线虫、似血矛线虫、辐射食道口线虫、粗纹食道口线虫、哥伦比亚食道口线虫的头端顶面。对弗氏旷口线虫和似血矛线虫口囊内齿或口矛的形态,三种食道口线虫的叶冠、化感器和感觉乳突进行了描述。