Modern turtle origins: the oldest known cryptodire

The discovery of a turtle in the Early Jurassic(185 million years before present) Kayenta Formation of northeastern Arizona provides significant evidence about the origin of modern turtles. This new taxon possesses many of the primitive features expected in the hypothetical common ancestor of pleurodires and cryptodires, the two groups of modern turtles. It is identified as the oldest known cryptodire because of the presence of a distinctive cryptodiran jaw mechanism consisting of a trochlea over the otic chamber that redirects the line of action of the adductor muscle. Aquatic habits appear to have developed very early in turtle evolution. Kayentachelys extends the known record of cryptodires back at least 45 million years and documents a very early stage in the evolution of modern turtles.     

茶子属中的茶子亚属和单性花亚属的核型研究

对茶子属中的两个最大亚属——茶子亚属和单性花亚属中部分种类的核型做了研究。结果表明，茶子亚属的８个种中有６个为二倍体（２ｎ＝２ｘ＝１６），１个为单倍体（２ｎ＝１ｘ＝８），１个为四倍体（２ｎ＝４ｘ＝３２），平均核型不对称系数为５９．４４％；单性花亚属的４个种均为二倍体（２ｎ＝２ｘ＝１６），平均核型不对称系数为６３．６％，由此可以看出，茶子属的进化是从染色体倍性和核型不对称性这两个方面进行的。     

四种紫花苜蓿的核型分析

为研究我国引进和本国育成的适于我国北方不同地区种植的四个紫花苜蓿(Medicago sativa)品种遗传基质的结构特征,对它们进行了细胞染色体的核型分析。试验利用植物压片法对四个品种:阿尔冈金(加拿大)、WL-323ML(美国)、WL-232HQ(美国)、中苜1号(中国农科院畜牧所用中外品种混合选育而成)进行了核型分析,结果表明:四个品种的染色体数目均相同(2n=32),统属于大染色体,但在核型组成上存在有一定的差异。四个品种中多数染色体为中部着丝点,核型多为对称型。但阿尔冈金、WL-232HQ及中苜1号同为2A型,它们相邻间染色体长度变化不大,进化程度相当,而WL-323ML为2C核型。第1,2对及第15,16对相邻间染色体长度变化大,余者变化小。它比前三个品种表现出更为进化的特点。阿尔冈金没有随体,WL-232HQ有1对随体,WL-323ML、中苜1号各有2对随体。     

The origin of the turtle body plan: bridging a famous morphological gap

A restudy of pareiasaurs reveals that these primitive reptiles are the nearest relatives of turtles. The two groups share numerous derived characters, such as a reduced presacral count, an acromion process, and a trochanter major, which are absent in other basal amniotes. Many traits long thought specific to chelonians also occur in pareiasaurs and must have evolved before the distinctive turtle shell appeared. Evidence uniting captorhinid or procolophonoids with turtles is shown to be weak. The phylogeny proposed here also suggests that certain features of the earliest turtle (Proganochelys) that have been interpreted as specializations, such as the large supratemporal and robust metacarpals, are primitive for turtles. In pareiasaurs, the osteoderms represent the precursors of the chelonian shell and the morphology of the anterior region is consistent with the idea that the shoulder girdle in turtles has migrated posteriorly into the rib cage.     

不同养殖模式对中华鳖营养品质的影响

[目的]研究不同养殖模式对中华鳖（Trionyz sinensis）营养品质的影响,为深入探讨提高原生态养殖鳖营养、保健功能的途径和方法提供理论依据.[方法]对原生态、池塘和温室养殖模式下中华鳖肌肉和裙边的基本营养成分及肌肉氨基酸、脂肪酸组成的差异进行比较分析.[结果]与池塘养殖鳖和温室养殖鳖相比,原生态养殖鳖的肌肉蛋白质、脂肪和胶原蛋白含量最高,水分含量最低;裙边水分、蛋白和胶原蛋白含量显著高于池塘养殖鳖和温室养殖鳖（P＜0.05,下同）,但脂肪含量最低.从3种鳖的肌肉中能检测出16种氨基酸,且肌肉氨基酸总量、必需氨基酸和鲜味氨基酸总量均以原生态养殖鳖最高.从中华鳖肌肉中共检测到21种脂肪酸,包括7种饱和脂肪酸、6种单不饱和脂肪酸、8种多不饱和脂肪酸;原生态养殖鳖的单不饱和脂肪酸总量显著高于池塘养殖鳖和温室养殖鳖,温室养殖鳖的不饱和脂肪酸总量最高,但除C18∶2n-6外,其他多不饱和脂肪酸含量均以原生态养殖鳖最高.[结论]原生态养殖鳖的品质优于池塘养殖鳖和温室养殖鳖.     

鳖的人工繁殖技术

鳖人工繁殖有关技术及影响鳖卵受精率、孵化率及稚鳖越冬成活率的研究表明,2a供试亲鳖8100只,产卵172229粒,受精率88.83％,孵化稚鳖141852只,孵化率为92.72％,其中利用自制亲鳖促性腺发育配合饲料投喂比天然饲料投喂的雌亲鳖产卵量提高23.32％;利用LRH-A对亲鳖进行人工催产的受精率为91.82％,比自然产卵受精率(85.13％)提高6.69％;保温越冬稚鳖4800只,成活率95.3％,比常温越冬成活率(81.75％)提高13.55％;平均饲养稚鳖229d,增重倍数为5.14,饲养幼鳖3400只,成活率97.01％,增重倍数为7.63。     

Olfactory-based orientation in artificially imprinted sea turtles

Sea turtles (Lepidochelys kempi) are being artificially imprinted to Padre Island, Texas, in an effort to establish a new nesting population. These turtles spent more time per exposure in solutions made of Padre Island sand and seawater than in control solutions in a multiple-choice test. This is evidence that sea turtles may detect differences in natural water samples and remember olfactory cues to which they were exposed neonatally and that these differences may affect their orientation behavior. This suggests that imprinting could be used as a conservation technique for establishing new breeding populations of endangered sea turtles.     

墨西哥辣椒的核型研究

本文对四川农业大学引种栽培的墨西哥辣椒（C.annuumvar.peperchiliJaiepeno)的核型进行了分析；其核型公式为：2n=2x=24=22m＋2sm，2A核型，平均臂比1．24，染色体长度比1．40。与国产的7个辣椒品种的核型进行了比较，发现其核型与国产辣椒有较大差异，似为亲缘关系较远的另一变种。并根据核型对其起源作了讨论。     

Winter dormancy in sea turtles: independent discovery and exploitation in the gulf of california by two local cultures

Documentation is reported for sea turtles overwintering on the sea bottom. Seri Indians have traditionally hunted nonmigrating dormant green turtles (Chelonia mydas) along the bottom of the Infiernillo Channel in the Gulf of California. Mexican fishermen independently discovered dormant turtles during winter 1972-1973, and with new hunting technologies are rapidly decimating these unusual stocks.     

食盐浸泡法消毒幼鳖的最适条件研究

[目的]探讨浸泡幼鳖的适宜食盐溶液浓度和正确的处理方法。[方法]将在清水中和离水条件下暂养24 h的中华鳖幼鳖分别浸入不同浓度的食盐溶液中,测定其体重和不同时间段的死亡数。[结果]清水组每组幼鳖的体重减少0.76~0.96 g,占始重的5.60%~6.00% 在食盐溶液中浸泡3 h后,其体重减少0.04~0.53 g,占浸泡前体重的0.26%~4.02% 当食盐浓度低于3%时,随食盐浓度的增大,其减重率增大。离水组每组幼鳖的体重减少2.11~6.18 g,占始重的3.90%~20.65% 体重为10.22~16.30 g的幼鳖的减重率为始重的13.74%~20.65%,体重为119.93~158.03 g的幼鳖的减重率为始重的3.90%~4.91% 0.5%食盐溶液组,其体重增加了0.18g,占浸泡前体重的1.74% 其余各组每组体重减少0.08~1.54 g,占浸泡前体重的0.58%~3.23%。食盐浓度在2.0%以下和6.0%以上时,幼鳖死亡率较高。[结论]食盐溶液的最适浓度为3.0%,浸泡时间不超过30 min。     

绿海龟健康幼体心肝肾功能血液生化指标参考值研究

采集了39只人工养殖的健康幼体绿海龟(1.5~2.5龄)、6只健康成体绿海龟(10~20龄)和3只野生成体绿海龟,用Beckman AU5800和TNI BECKMAN Access 2测定和分析了反映绿海龟心肝肾功能的17项血液生化指标,结果发现野生个体的生化指标与人工养殖的绿海龟差异较大,谷草转氨酶(P=0.002)、白蛋白(P=0.015)、碱性磷酸酶(P=0.010)、谷丙转氨酶(P=0.010)等均有明显差异,人工养殖绿海龟除碱性磷酸酶与年龄呈负相关外没有明显差异,不同性别的个体在生化指标上差异不显著。本实验结果与野生绿海龟各研究结果对比发现,野生个体的指标差异非常显著,难以作为健康指标的参考。本研究建立了人工绿海龟的心肝肾功能血液生化指标参考值,为野生绿海龟血液生化研究提供参考,为指导绿海龟养殖过程中的疾病早期诊断和预防提供依据。     

野生鳖与养殖鳖肌肉营养、保健价值的比较研究

分析了中华鳖（Ｔｔｒｏｎｙｘ ｓｉｎｅｎｓｉｓ）肌肉中蛋白质及氨基酸、脂肪及脂肪酸等营养成分的含量,并与野生鳖肌肉营养成分作对照。结果表明：养殖鳖肌肉中蛋白质及赖氨酸、谷氨酸和丙氨酸的含量明显降低,而缬氨酸、甘氨酸和丝氨酸的含量显著提高;脂肪及二十碳五烯酸和二十二碳六烯酸的含量显著增加,但亚麻酸和花生四烯酸的含量明显降低;胆固醇的含量显著增高,此外发现,缬氨酸为鳖肉食用营养的第一限制性氨基酸,在此     

温度对广西拟水龟生长的影响

为探明温度与幼龟的生长关系,为幼龟饲养提供依据,对不同温度下幼龟的重量、增重量、背甲长、背甲宽和体厚等生产性能进行测定。结果表明:各处理幼龟的日增重量随饲养时间增加而增加,且呈不断增大趋势;40d后,在(28±0.5)℃、(30±0.5)℃和(32±0.5)℃下,平均体重增加6.48g/只、7.68g/只和6.69g/只,与对照(5.02g/只)相比有显著差异;背甲长、背甲宽和体厚增加分别为11.78 mm、10.26mm、3.25mm,16.34 mm、13.58 mm、4.77 mm,11.24 mm、9.89 mm、3.12 mm,明显优于对照(8.26mm、7.07mm、1.45mm)。当水温为(30±0.5)℃时,广西拟水龟幼龟体重、背甲长、背甲宽、体厚增加最快,为饲养广西拟水龟的最佳温度。     

池塘鳖与温室鳖体组成和生化=组成的比较研究

比较分析了池塘养中华鳖（Trionyx sinensis）与温室养中华鳖体组成和生化组成的差异。结果表明，与池塘鳖相比，温室鳖四肢沉积较多的脂肪，肝脏质量显著地增加。此外还发现，温室鳖的肌肉脂肪、胆固醇的含量、脂肪的碘值和裙边的胶原蛋白可溶率都显著地提高，但肌肉和脂肪的感官色泽、肌肉的蛋白质及其谷氨酸和丙氨酸的含量、裙边的食用粘度及其相关的总胶原蛋白和可溶性胶原蛋白含量却明显地降低。     

Late triassic turtles from South america

The discovery of Triassic (Norian) turtles from the northwest part of Argentina extends the South American record of turtles by 60 million years. Two skeletons, one almost complete, represent a new genus and species of a basal turtle, Palaeochersis talampayensis. This turtle is a member of the family Australochelidae that was recently erected for Australochelys africanus from the Lower Jurassic of South Africa. Here, it is proposed that Australochelidae is the sister group of Proterochersis plus Casichelydia, that turtles were diverse by the Late Triassic, and that Casichelydia probably originated during the Jurassic.     

岷江柏木和西藏柏木的核型及亲缘关系研究

本文首次报导了岷江柏木（Ｃｕｒｐｒｅｓｓｕｓｃｈｅｎｇｉａｎａ）和西藏柏木（Ｃｕｐｒｅｓｓｕｓｔｏｒｕｌｏｓａ）的体细胞核型。两种有相同的核型公式Ｋ（２ｎ）＝２２＝２０ｍ＋２ｓｍ，同属１Ａ核型，其它核型数据相近。岷江柏木为中国特有种，西藏柏木主产我国，结合生态、地理分布特征及生化分析资料，讨论了两者的亲缘关系及生态同群种的一致性趋势。     

基于两个核基因序列研究龟鳖类的系统进化特征

为从核基因的角度探讨龟鳖类的系统发育特征,采用PCR扩增和测序的方法,获得两种龟的R35内含子部分序列以及6种龟的RAG2基因部分序列,结合NCBI其它龟鳖的同源序列一并进行分析。结果表明：将R35序列比对后得到941 bp的一致序列,将RAG2比对后得到620 bp的一致序列,二者合并后,比对排序后得到1561 bp的一致序列,其中共有505个可变核苷酸位点,总变异率为32.35%;简约信息位点为239个,插入/缺失为139个,转换/颠换比率为1.64。碱基A、T、G、C的平均含量分别为29.5%、28.5%、22.8%、19.2%。海龟科和鳄龟科之间Kimura双参数（K-2-P）遗传距离最小（0.025）,鳖科和南美侧颈龟科之间的遗传距离最大（0.182）。分子系统树结果显示：1）陆龟科与潮龟科先聚在一起,再与龟科聚在一起,陆龟科与潮龟科构成一个单系类群;2）支持陆龟总科与鳄龟科＋海龟总科构成姐妹群;3）鳄龟科和海龟总科是姐妹群的关系。     

鳖疖疮病病原的分离与鉴定

1988年冬到1989年春,我院从某特种水产科研所引进的稚鳘发生了一种新的传染病,病鳖体表形成疖状病灶,暂名为鳖疖疮病。从病鳖的病灶和脏器内分离到两株细菌,经腹腔注射和伤口涂抹能使健康鳖表现出与自然发病相同的病症。两菌株的特性基本一致,被鉴定为点状产气单胞菌点状亚种。     

Hybrid speciation in experimental populations of yeast

Most models of speciation require gradual change and geographic or ecological isolation for new species to arise. Homoploid hybrid speciation occurred readily between Saccharomyces cerevisiae and Saccharomyces paradoxus. Hybrids had high self-fertility (about 82%), low fertility when backcrossed to either parental species (about 7.5%), and vigorous growth under different thermal environments that favored one or the other of the parental species. Extensive karyotypic changes (tetrasomy) were observed in the hybrids, although genic incompatibilities accounted for 50% of the variation in self-fertility.     

4种薯蓣属植物的核型分析

 采用染色体压片技术对薯蓣属(Dioscorea)4种植物进行核型研究。结果显示小花盾叶薯蓣(Dparviflora CTTing)的染色体数目为2n=2x=20,核型公式K(2n)=20=8m+12sm;盾叶薯蓣(野生种)(Dzingiberensis CH Wright)的染色体数目为2n=2x=20,核型公式K(2n)=20=14m+6sm;盾叶薯蓣(Dzingiberensis CH Wright)栽培株系A-02-6的染色体数目为2n=4x=40,核型公式K(2n)=40=20m+18sm+2st;黄独(Dbulbifera L)的染色体数目为2n=8x=80,核型公式K(2n）=80=34m +46sm;山药(薯蓣Dopposita Thunb)的染色体数目为2n=14x+4=144,核型公式K（2n）=144=57m+84sm+3st。结果表明：薯蓣属是染色体数目和倍性复杂并且存在许多多倍体的植物群,核型上也存在一定差异。