The effect of trematode infection on amphibian limb development and survivorship

The causes of amphibian deformities and their role in widespread amphibian declines remain conjectural. Severe limb abnormalities were induced at high frequencies in Pacific treefrogs (Hyla regilla) exposed to cercariae of a trematode parasite (Ribeiroia sp.). The abnormalities closely matched those observed at field sites, and an increase in parasite density caused an increase in abnormality frequency and a decline in tadpole survivorship. These findings call for further investigation of parasite infection as a cause of amphibian deformities in other sites and species.     

COLOR POLYMORPHISM IN PACIFIC TREE FROGS

Crosses between green and non-green Hyla regilla suggest that green color is determined by genes at two loci; each loci must have a dominant gene. Red is the result of a recessive gene and brown a dominant gene. The frequency of frogs with each color varies in different populations.     

Immunological resolution of a diploid-tetraploid species complex of tree frogs

Micro-complement fixation studies of eastern and western populations of the North American tree frog Hyla chrysoscelis reveal they have been genetically isolated for about 4 million years. Immunological comparisons of populations of the cryptic tetraploid Hyla versicolor indicate a recent origin, from hybridization between eastern and western H. chrysoscelis.     

几种鲶形目鱼类血清蛋白的比较研究

长吻鮠(Leiocassis longirostris Giinther)、大鳍鳠(Hemiba-grus macropterus Bleeker)、南方大口鲶(Silurus soldatorvi meridionalisChen).鲶鱼(Silurus asotus Linnaeus)的血清蛋白,经盘状电泳分离,从负极到正极可分为脂蛋白、球蛋白、运铁蛋白、清蛋白和前清蛋白5个组分。电泳图谱具种间差异,亲缘关系越远差异越大。同种鱼雌、雄间的电泳图谱基本相似,但不完全相同,鲶鱼具有雌性特异蛋白。     

Hybrid tree frogs: vocalizations of males and selective phonotaxis of females

Male hybrids of reciprocal crosses between gray and pinewoods tree frogs (Hyla chtysoscelis x H. femoralis) that were raised to sexual maturity in the laboratory produced distinctive vocalizations. Hybrid females preferred the calls of hybrids to calls of gray tree frogs and also chose synthetic calls with a pulse repetition rate typical of the hybrids in preference to calls with a rate typical of pinewoods tree frogs.     

Polyploidy in the common tree toad Hyla versicolor Le Conte

A karyotype of the first known naturally occurring anuran polyploid in North America is described. Hyla versicolor, the common tree toad, is tetraploid (2n-->4n=48). Individual chromosmes representing, each set of four of the Hyla versicolor karyotype correspond closely with those of the diploid (2n = 24) Hyla andersonii karyotype.     

玉簪新品种在山东滨州的引种试验

[目的]筛选适宜在山东滨州市种植的玉簪新品种。[方法]以引自北京、上海的13个玉簪新品种为试材,观察记录其在滨州的物候期、适应性,并对其观赏特性进行分析。[结果]引进的13个玉簪品种在滨州的生长表现不一,物候期差异较大。"冰与火""巨无霸""爱国者""首霜""神枪手"等9个品种,适应性较好,观赏性状优良,适合在滨州进行栽培和园林应用;"大父""威严"等4个品种,在滨州地区整体表现不良,不适合进行大规模园林应用。[结论]该研究可为玉簪品种在滨州市的推广应用提供依据。     

安徽省小麦孢囊线虫的发生分布与鉴定

为了解小麦孢囊线虫(Cereal cyst nematode,CCN)在安徽省的分布和主要麦区CCN的种类,以及群体间关系,调查了淮北等麦区小麦根系白雌虫,用"Zig-Zag"法在怀远等地采集土样,用Fenwick&Oostenbrink法分离土样中的孢囊并孵化得2龄幼虫,利用孢囊阴门锥形态及de-man法鉴定CCN种类,扩增ITS特征片段,用MEGA5.05构建系统发育树。结果表明,安徽省52%采样点检出CCN,淮河以北采样点均检出CCN,江淮麦区7%的采样点检出CCN,长江以南麦区采样点未检出CCN。发生在怀远、凤台、灵璧、界首和颍上麦区小麦根际CCN鉴定为禾谷孢囊线虫(Heterodera avenae),淮河以北发生H.avenae麦区占淮北小麦种植面积的41.6%,另外,怀远H.avenae群体和其他群体亲缘关系较远,群体间形态有一定差异,但和亲缘关系差异无一致性。     

Erratum

In reference 5 of "Eastern equine encephalomyelitis virus isolated from three species of Diptera from Georgia," by L. H. Karstad et al. [Science 125, 396 (1 Mar. 1957)], the name of J. E. McCroan is incorrectly spelled as Croan.     

八种中国原产鼠尾草属植物耐热性比较

以上海辰山植物园引种驯化的8种中国原产鼠尾草属(Salvia L.)植物为材料,测定了其高温半致死温度(LT50)和叶绿素相对含量(SAPD值),比较这8种植物的耐热性差异,从而对其在引种地的高温适应性做出分析与评价。结果表明,8种鼠尾草属植物的LT50值在50~57℃,且均呈"S"型曲线上升。8种植物的耐热性从强到弱依次排序为:贵州鼠尾草(Salvia cavaleriei Lévl.)红根草(S.prionitis Hance)南川鼠尾草(S.nanchuanensis H.T.Sun)血盆草(S.cavaleriei Lévl.var.simplicifolia Stib.)云南鼠尾草(S.yunnanensis C.H.Wright)美丽鼠尾草(S.meiliensis S.W.Su)南丹参(S.bowleyana Dunn)佛光草(S.substolonifera E.Peter)。利用Spearman秩相关性分析比较,结果表明,各植物的LT50值与SAPD值大小排序呈显著正相关,可以作为评价鼠尾草属植物耐热性的指标。     

Bayesian inference towards the resolution of molecular evolution:application to the "Trichoderma harzianum sensu lato" clade

The Hypocrea lixii/Trichoderma harzianum species aggregate contains a group of taxa (H. lixii /T. harzianum, T. aggressivum, T. tomentosum, T. cerinum, T. velutinum, H. tawa) of which some (e.g. T. harzianum) are important for biocontrol of plant pathogenic fungi in agriculture, whereas others are aggressive pathogens of Agaricus spp. and Pleurotus spp. in mushroom farms (T. aggressivum), or opportunistic pathogens of immunocompromised mammals including humans (T. harzianum). We ch…     

禽流感与人类健康

禽流感(avian influenza,AI)是由A型流感病毒(avian influenza virus)引起的一种禽类感染征或疾病综合症,高致病性禽流感(highly pathogenic avian influenza,HPAI)可引起禽类100％的死亡。由于抗原转变和抗原漂移,禽流感病毒是高度可变的。人禽流感是指高致病性禽流感病毒跨越物种界限,引起人类感染的一种新发传染病。目前,全球已发现H5N1、H7N7、H9N2等亚型禽流感病毒可感染人类。但目前还没有发现禽流感病毒具有在人群中相互传播的能力。对禽流感必须采用积极的预防策略。在加强监测的基础上,对家禽采用扑杀和免疫相结合的措施,可以有效地控制禽流感的流行。研制人类流感疫苗,是预防新的流感病毒株的流行的可靠保证。     

SPECTROPHOTOMETRIC TITRATIONS OF HUMAN SERUM ALBUMIN AND REDUCED CARBOXYMETHYLATED ALBUMIN

The tyrosyl groups of reduced and carboxymethylated human serum albumin, in which all disulfide bonds are broken, ionize at lower pH than those of native albumin, in spite of the greater negative charge on the protein produced by the S-carboxy-methyl groups. The heat and entropy of ionization of these groups in the reduced albumin are also "normal," in contrast to native albumin. Spectro-photometric titrations at 244 and 295 mmicro give equivalent results. The more open structure of the reduced albumin, as compared with the native protein, presumably allows the tyrosine groups to come freely into contact with solvent. In acid solutions the heights of the two peaks at 236 and 287 mmicro in the difference spectrum (albumin at pH 7 against albumin at a lower pH) are strictly proportional over the whole course of the titration. Both peaks apparently arise from changes in the environment of tyrosyl residues, rather than from more general conformational changes.     

Albumin and Australian frogs: molecular data a challenge to speciation model

Vertebrate speciation in the southwest of Australia has long been viewed as resulting from multiple invasions of eastern source stocks during the Pleistocene. Microcomplement fixation studies of serum albumin evolution in frogs of the genus Heleioporus provide the first hard data on age and phylogenetic relationships among species in this genus and lead to rejection of the multiple invasion model in favor of speciation occurring in Western Australia. The albumin molecular clock was used to estimate that the species divergences in this genus occurred between 4 million to 12 million years ago in the late Tertiary (Pliocene-Miocene), rather than in the Quaternary (the last 2 million years).     

一种高效提取虎耳草科植物基因组DNA的方法

[目的]探索从虎耳草科植物中提取DNA的有效方法。[方法]采用改进的CTAB法,从11种虎耳草科植物中提取DNA。以提取的DNA为模板,利用通用引物"psbAF"和"trnHR"对虎耳草科植物叶绿体DNApsbA-trnH片段进行PCR扩增。[结果]通过该方法提取的DNA纯度较高,质量较好。用所得DNA进行psbA-trnH扩增的产量高,可用于后续的测序等分析。对山地虎耳草的PCR产物纯化后进行测序,得到262 bp的序列。将其与GenBank中的虎耳草属其他植物的psbA-trnH序列进行比对分析,证实该序列为目标psbA-trnH片段的区域。[结论]该方法可有效去除次生物质对DNA的干扰,提取的基因组DNA可用于叶绿体psbA-trnH测序分析和其他遗传学分析。     

Chloramphenicol-specific antibody

Antibody to the antibiotic chloramphenicol was obtained by immunizing rabbits with a chloramphenicol derivative coupled to bovine gamma globulin. Production of antibody was demonstrated by the precipitin and complement fixation reactions with "reduced chloramphenicol" coupled to rabbit serum albumin as the test antigen. Specificity of the antibody was confirmed in that crystalline chloramphenicol completely inhibited complement fixation and precipitin reactions. "reduced chloramphenicol" coupled to human serum albumin provides an antigen for the detection of antibody to chloramphenicol, if it occurs in human serum in dyscrasias. With quantitative complement fixation, as little as 10(-5) microg (4 x 10(-14) mole) of chloramphenicol was detectable by the inhibition assay.     

金沙江峡谷退耕经济林地昆虫多样性分析

调查滇西北金沙江峡谷不同退耕经济林地和对照样地的昆虫组成,以喜地表活动的蚁科、植食性的蝗总科和捕食性瓢虫种类为对象,分析Margalef丰富度指数(R)、Shannon-W ie-ner多样性指数(H)和Pielou均匀度指数(J).结果显示:样地A昆虫共10目33科,样地B有6目26科,样地C为6目23科,样地D是7目26科.步甲科、瓢甲科、叶甲科、蝽科、长蝽科、土蝽科和斑腿蝗科等种类在较晚退耕的林地里常见.昆虫物种Margalef丰富度指数以2001年退耕木亡果林地最高,R=3.413 4;Shannon-W iener多样性指数则以2000年退耕还林的青梅林地为最大,H=2.090 1;Pielou均匀度指数值最高的是2001年退耕的撂荒坡地,J=0.999 6.从昆虫多样性来看,退耕还林有利于促进金沙江峡谷的生态恢复.     

Helicoplacoidea: A New Class of Echinoderms

A fusiform, spirally coiled and pleated, free-living, heavily placate echinoderm with an expansible test has been discovered in the Lower Cambrian Olenellus zone of California. It is characterized by 10 "interambulacral" areas, a single principal endothecal ambulacrum with a short branch, and oral and apical regions at opposite poles. A new class, the Helicoplacoidea is proposed for the new genus Helicoplacus, with two new species, H. gilberti (type species) and H. curtisi.     

红尾荷马条鳅形态差异及其分类地位的研究

为探讨红尾荷马条鳅(Homatula variegata)不同地理居群之间的形态差异,对采自黄河上游、长江中游、长江上游和珠江上游的78尾标本的18个可量性状进行主成分分析。依据分析结果,结合对其鳞片覆盖状况、肠型、体色等形态型的检视,重新评价了该物种的分类地位。研究结果显示,珠江上游居群应该由亚种提升为一个独立的种;长江上游嘉陵江和雅砻江标本的差异明显,分别代表了两个不同的物种,即贝氏荷马条鳅(H.berezowskii)和红尾荷马条鳅;而此次检视的长江中游汉江水系标本比较少,分类地位尚无法确定,需要进一步研究;黄河上游的标本不同于红尾荷马条鳅和贝氏荷马条鳅,为一个未命名的物种。     

福建稻田潜根线虫(Hirschmanniella spp.)七个种鉴定初报

本文记述了1982～1985年采自福建稻田的潜根线虫属(Hirschmanniella Lue & Goodey,1963)7个种:H.oryzea、H.microtyla,H.caudacrena、H.gracilis、H.mucronata、H.belii和H.imamuri。H.oryzea和H.microtyla为福建的常见种。在福建水稻田中往往同时栖居着两个或两个种以上的潜根线虫群体。除H.oryzea外,其余6个种均为福建省首次记录。