Reassessment of the isopod crustacean Aega deshaysiana (Milne Edwards, 1840) (Cymothoida: Aegidae): a world-wide complex of 21 species

Aega deshaysiana (Milne Edwards, 1840) and A. antillensis Schioedte & Meinert, 1879, have long been confounded, with all records eventually becoming regarded as belonging to one globally distributed species, namely A. deshaysiana. These two species are redescribed and differentiated, with A. schioedteana Bovallius, 1885 remaining in synonymy with A. deshaysiana. Aega deshaysiana occurs only in the eastern North Atlantic and Mediterranean, while A. antillensis is known only from the Caribbean and Gulf of Mexico. A further two named species are redescribed: A. excisa Richardson, 1910, previously placed in synonymy with A. deshaysiana, and A. magnifica (Dana, 1852). A neotype is designated for A. magnifica. This ‘complex’ or group of Aega species is distinguished from the others by their large eyes, which are usually medially united and occupy most of the head, their large adult size (20–60 mm), a posteriorly acute and defined pleotelson apex, and the uropod rami not extending posteriorly beyond the pleotelson, with exopod held at an oblique angle to the endopod and deeply notched endopod lateral margin. The group is not necessarily monophyletic, as there is a gradation in the depth of the uropod notch from deep to scarcely evident, and in eye size from entirely occupying the head to just separate (though the eyes are always large). Twelve new species in the group are described. All species are considered to be micropredators of fishes and elasmobranches, although prey records are few and unreliable owing to the readiness of these isopods to detach. Species of the group have been recorded from depths varying between 10 m and 600 m and occasionally deeper. Several have extensive distributions ranging from the Southern Ocean to tropical waters. The group is represented in all oceans. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142 , 135–232.     

Characterization of Mycoplasmatales Virus <Emphasis Type="Italic">laidlawii</Emphasis> 1

A recent report¹ described for the first time the isolation of a virus that infects a species of mycoplasma. This agent, now designated MVL1, has been purified, examined in the electron microscope and its nucleic acid type determined. Cultures of M. laidlawii strain BN1 (ref. 1), grown in glucose serum broth or agar², were inoculated with virus during their log phase and incubated at 37° C for 18–24 h. On solid medium, plaques were observed in the mycoplasmal lawn from which virus was harvested by flooding the plate with phosphate buffered saline (PBS), pH 7.3, for 3–5 h. The titre of the virus was estimated as previously reported¹.     

GoPipe: 批量序列的Gene Ontology 注释和统计分析

随着后基因组时代的到来,批量的测序,特别是 EST 的测序,逐渐成为普通实验室的日常工作 . 这些新的序列往往需要进行批量的 Gene Ontology (GO) 的注释及随后的统计分析 . 但是目前除了 Goblet 以外,并没有软件适合对未知序列进行批量的 GO 注释,而 GoBlet 因为具有上载量的限制,以及仅仅利用 BLAST 作为预测工具,所以仍有许多不足之处 . 开发了一个软件包 GoPipe ,通过整合 BLAST 和 InterProScan 的结果来进行序列注释,并提供了进一步作统计比较的工具 . 主程序接收任意个 BLAST 和 InterProScan 的结果文件,并依次进行文本分析、数据整合、去除冗余、统计分析和显示等工作 . 还提供了统计的工具来比较不同输入对 GO 的分布来挖掘生物学意义 . 另外,在交集工作模式下,程序取 InterProScan 和 BLAST 结果的交集, 在测试数据集中,其精确度达到 99.1% ,这大大超过了 InterProScan 本身对 GO 预测的精确度,而敏感度只是稍微下降 . 较高的精确度、较快的速度和较大的灵活性使它成为对未知序列进行批量 Gene Ontology 注释的理想的工具 . 上述软件包可以在网站 (http://gopipe.fishgenome.org/ ) 免费获得或者与作者联系获取 .     

Elevated CO2 and nutrient addition after soil N cycling and N trace gas fluxes with early season wet-up in a California annual grassland

We examined the effects of growth carbon dioxide (CO₂)concentration and soil nutrient availability on nitrogen (N)transformations and N trace gas fluxes in California grasslandmicrocosms during early-season wet-up, a time when rates of Ntransformation and N trace gas flux are high. After plant senescenceand summer drought, we simulated the first fall rains and examined Ncycling. Growth at elevated CO₂ increased root productionand root carbon:nitrogen ratio. Under nutrient enrichment, elevatedCO₂ increased microbial N immobilization during wet-up,leading to a 43% reduction in gross nitrification anda 55% reduction in NO emission from soil. ElevatedCO₂ increased microbial N immobilization at ambientnutrients, but did not alter nitrification or NO emission. ElevatedCO₂ did not alter soil emission of N₂O ateither nutrient level. Addition of NPK fertilizer (1:1:1) stimulatedN mineralization and nitrification, leading to increased N₂Oand NO emission from soil. The results of our study support a mechanisticmodel in which elevated CO₂ alters soil N cycling and NOemission: increased root production and increased C:N ratio in elevatedCO₂ stimulate N immobilization, thereby decreasingnitrification and associated NO emission when nutrients are abundant.This model is consistent with our basic understanding of how C availabilityinfluences soil N cycling and thus may apply to many terrestrial ecosystems.     

Responses by four seabird species to a fluctuating availability of Cape Anchovy Engraulis capensis off South Africa

In recent years, Cape Anchovy Engraulis capensis has been the most important food for four seabirds breeding in South Africa–African Penguin Spheniscus demersus, Cape Gannet Morus capensis, Cape Cormorant Phalacrocorax capensis and Swift Tern Sterna bergii. Between 1984 and 1992, biomass of spawning anchovy fluctuated between about 0.5 and 1.75 million tons. Abundance of anchovy was significantly related to numbers of chicks fledged by African Penguins, occurrence of anchovy in the diet of Cape Gannets and numbers of Cape Cormorants and Swift Terns that attempted to breed. Numbers of African Penguins and Cape Gannets that attempted breeding probably also were influenced by abundance of anchovy. African Penguins and Cape Cormorants abandoned nests when anchovy were scarce and deferred breeding until anchovy became more plentiful. Survival of immature African Penguins in a period of anchovy scarcity was enhanced by availability of South African Sardine Sardinops sagax as an alternative food. When anchovy abundance was low, Cape Gannets fed on sardine.