共查询到20条相似文献,搜索用时 140 毫秒
1.
野生麋鹿(Elaphurus davidianus Milne-Edwards(1866)是一种近代才绝灭于我国的哺乳动物,也是第四纪我国的一个土著分子,曾发现过大量的化石。这就为我们利用这个物种的材料研究动物的绝灭和它们的体型增大或缩小的关系提供了可能性。麋鹿化石标本与它的现生标本在尺寸上有一定的差异。角枝尺寸,最大数据的项目多为化石的标本,而不是现生的标本。例如:节部最大径,化石的最大值100.5(单位:mm,下同)大于现生的73、67、64、68、76;主干长,化石的最大值207,大于现在的170、142、150、148、155、152;后枝长,化石的最大值820,大于现生的700、715… 相似文献
2.
野生麋鹿绝灭原因的探讨 总被引:3,自引:0,他引:3
糜鹿(Elaphurus davidianus Milne-Edwards)是我国特产的珍兽。野生者已不复存在。现存者以目前英国驯养的鹿群为最有名。国内仅个别大的动物园才有少数饲养。 我们曾推断过我国野生糜鹿绝灭的时间(曹克清,1978)和地区(曹克清,1982)。本文拟就它们绝灭的主要原因试作专题探讨。我们认为它们的绝灭与自然的人为的和动物本身的因素有关,特别是人为因素。 相似文献
3.
早在1937年,杨钟健曾研究过磁县西部的一些零碎化石,提出河北平原有中新世地层的存在。胡长康(1959)研究了磁县九龙口一种曾在内蒙古通古尔动物群中发现过的巨爪兽,进一步确认磁县九龙口含化石地层的时代为中新世晚期。1970年九龙口村群众报告又有化石发现,中国科学院古脊椎动物与古人类研究所派翟人杰和吴新智同志前往调查。化石大部分产自黄色砂岩中的红色粘土结核内,个别产自砂岩。采集的标本数量和代表的种类都较丰富,对我国中新世地层和动物群的研究具有重要意义。这里记述的绝大部分标本是这次采集的(少数为过去收集的同一地点的材料)。总计有3个目、13个种和若干未定种属: 相似文献
4.
<正>1962年在我国广东南雄盆地首次发现了阶齿兽类化石(周明镇等,1973;郑家坚等, 1973),随后在安徽潜山、湖南茶陵、陕西石门、江西大余等地的中古新世地层中相继发现该类动物的化石材料,尤其是在广东南雄、江西大余和湖南茶陵三个地点,有大量的阶齿兽类化石产出。阶齿兽类在中古新世时在亚洲南部是广泛分布的。本文记述的阶齿兽材料是2003年在江西池江盆地发掘到的,此标本与已知的阶齿兽属中各种均有明显差别, 故建立一新种——丁氏阶齿兽(Bemalambda dingae sp.nov.)。 相似文献
5.
野生麋鹿绝灭时间初探 总被引:3,自引:0,他引:3
麋鹿或称四不象(Elaphurus davidianus),是与大熊猫(Ailuropoda mdanoleuca)齐名媲美的我国另一种特产的世界珍兽。不久前,我们曾经报道它的8个化石地点,并且总结我国东部(大约东经111°以东)北起东北辽宁省康平,南止华东浙江省余姚(北纬30—43°左右)已发现的第四纪的27个化石地点(曹克清,1975)。迄今不到2年又发现了39个新的地点,短时间内化石地点增加一倍以上(表1)。新的发现扩大了更新世中期的分布范围,增加了河北省的化石层位,具体化了山东省的化石地点,填补了江苏省某些地区的空白,大大丰富了我国这种动物的地史地理分布,同时,也帮助了我们对野生麋鹿绝灭时间试行探讨。这些丰富的地史地理分布资料(图1)表明:第四纪麋鹿以更新世晚期一全新世发现 相似文献
6.
滇东路南盆地的下第三系,一般统称为“路南群”,包括下渐新统和上始新统两组地层,是我国南方早第三纪地层对比的一个重要剖面。路南盆地过去发现的哺乳类化石,奇蹄类的种类最多。由于化石材料大都比较零散,或产地不肯定,因而引起对于该区早第三纪地层划分及动物群性质认识上的意见分歧。“只有感觉的材料十分丰富(不是零碎不全)和合于实际(不是错觉),才能根据这样的材料造出正确的概念和论理来。”我们这里记述的化石,包括一些新的资料,多数有确实的地点记录,对过去的材料作了一些补充和修订。虽然材料还不十分丰富,但对了解地层时代,和某些奇蹄类性质,仍有一定帮助。本文内容主要包括四个方面:(1)“路南雷兽”的性质和时代的讨论;(2)摸类和原始犀类三个新种的记述;(3)几种獏和犀类形态方面的补充,包括原跑犀和特氏獏的下颊齿列,方齿始爪兽的前臼齿的性质,都是过去不知道的;(4)我国始新世几种奇蹄类的属、种的性质和分类位置的讨论。本文中记述的标本,全部是北京地质陈列馆胡承志同志在1957年采集的。标本照片是王哲夫同志摄制的。 相似文献
7.
河南卢氏盆地的中兽化石 总被引:1,自引:1,他引:0
记述了河南卢氏盆地的中兽科化石材料,命名了强中兽属一新种———李氏强中兽(Harpagolestesleeisp.nov.)。该种P4后附尖非常发育、向颊侧突出;M2的原尖长,前端偏于舌侧、后端偏于颊侧,冠面轮廓近于长方形。报道了东方强中兽(Harpagolestesorientalis)的第一件下颌标本,并对该种的特征进行了补充和修订。描述的一个厚中兽未定种(Pachyaenasp.)可能是该属已知最晚的代表。还鉴定出两件Mongolestes属的标本及一件属种未定的中兽科化石。 相似文献
8.
湖北宜昌冠齿兽化石的新材料 总被引:1,自引:0,他引:1
本文记述了产于湖北宜昌梅子溪的冠齿兽类化石的一新种:杨氏方齿兽 Manteodon you-ngi sp.nov.1936年德日进和杨钟健曾记述了一种产自同一地区的冠齿兽类化石(Eudinoce-ras cf.kholobochiensis)。它的大小和性状与杨氏方齿冠齿兽十分相近,因此被归列到杨氏方齿冠齿兽这个种。宜昌地区含冠齿兽化石的两个地点(梅子溪和洋溪)的地层,其时代与湖北玉皇顶组的时代应相当或稍晚,但不会晚于中始新世。 相似文献
9.
现生的四不像鹿(Elaphurus davidianus)是鹿亚科(Cervinae)中独特的一种,我国的特产动物,世界的珍兽。由于旧中国沦为半殖民地,因而过去这些科学材料多为外国人研究,1866年由米尔恩-爱德华兹(Milne-Edwards)根据帝国主义御用学者法国传教士达维德(David)从北京南苑搞回法国巴黎博物馆的标本研究建立。1930年,德日进和皮韦托(Teilhard and Piveteau)在研究中国河北泥河湾维拉方期哺乳动物群时,又发现一类新的化石鹿角,分叉性质相类似,前枝和后枝都有分叉,便在该属下建立一新种,叫四不像鹿双叉种(E.bifurcatus)。但这个种分布面积不广,且基本上只有更新世初期才有,从未发现于此后地层(包括E.of.bifurcatus)。1933年,索尔比(Sowerby)根据安阳殷墟的发现,在真鹿属(Cervus)的名下记述了一个新种,谓真鹿属梅氏种[Cervus(Rucervus)men- 相似文献
10.
<正> 1975年夏,我们在广南盆地的莲峰十三队及小广南两个地点采集到一批哺乳类化石。初步观察,这批化石属于老第三纪的哺乳类。莲峰的标本产于一套红色地层的石膏夹层中,可能归于巨犀(Indricotherium cf.intermedium),时代为渐新世。小广南的标本亦是出自红色地层里的石膏层,化石种类有原蹄犀(Prohyracodon sp.),标本有带右上第二至第四前臼齿的颌骨和两件残颌骨;新脊犀(Caenolophus sp.),材料有带牙齿的下颌骨前部一段,时代为始新世。由此可见,广南盆地存在两个层位的化石层。广南化石点的发现,扩大了我们对于省区内 相似文献
11.
Molecular diversity of the 5S nuclear ribosomal DNA in Campeiostachys with StHY haplome constitution
Cai‐Rong Yang Bernard R. Baum Douglas A. Johnson Hai‐Qin Zhang Yong‐Hong Zhou 《植物分类学报:英文版》2020,58(1):69-76
To detect the genomic constitutions and investigate the evolutionary relationships between Campeiostachys Drobov and Elymus L. species, we have cloned and analyzed 271 5S nuclear ribosomal DNA sequences from 27 accessions of these species, mostly of Chinese origin. We identified Long H1, Short S1, and Long Y1 unit classes in nine Campeiostachys or Elymus species. The identification of the three orthologous unit classes was confirmed by the neighbor‐joining tree of each unit class from PAUP and the phylogeny tree of three unit classes from MrBayes. The results suggested that these Elymus species comprise StYH haplomes and should be included in Campeiostachys. The phylogeny tree showed a clear separation between the S1 unit class and Y1 unit class. However, Y1 unit class sequences formed a sister clade to the S1 unit class, implying that although the St and Y haplomes might have some affinity, they are distinct from one another. The phylogeny tree also indicated that the five species in sect. Turczaninovia (C. dahurica var. cylindrica, C. dahurica var. dahurica, C. dahurica var. tangutorum, E. purpuraristatus, and E. dahuricus Turcz. ex Griseb. var. violeus C. P. Wang & H. L. Yang) might share a more recent common ancestor, whereas the four species in sect. Elymus (C. nutans, E. breviaristatus (Keng) Keng ex Keng f., E. sinosubmuticus (Keng) Keng f., and E. atratus (Nevski) Hand.‐Mazz.) share a close relationship. By identifying only one type of unit class for each haplome, we propose that the 5S nuclear ribosomal DNA sequences of species within Campeiostachys might have undergone haplome‐specific concerted evolution. 相似文献
12.
13.
粗糠树是紫草科厚壳村亚科厚壳树属植物,广布于我国长江以南及台湾,在西藏、青海、甘肃及陕西也有少量分布。学名通常采用E.dicksoniHance (1862),标式标本采自湖北。 相似文献
14.
Chao Fang Jun Liu Ting Zhang Tong Su Shichen Li Qun Cheng Lingping Kong Xiaoming Li Tiantian Bu Haiyang Li Lidong Dong Sijia Lu Fanjiang Kong Baohui Liu 《植物学报(英文版)》2021,63(6):995-1003
Soybean (Glycine max) is an important legume crop that was domesticated in temperate regions. Soybean varieties from these regions generally mature early and exhibit extremely low yield when grown under inductive short-day (SD) conditions at low latitudes. The long-juvenile (LJ) trait, which is characterized by delayed flowering and maturity, and improved yield under SD conditions, allowed the cultivation of soybean to expand to lower latitudes. Two major loci control the LJ trait: J and E6. In the current study, positional cloning, sequence analysis, and transgenic complementation confirmed that E6 is a novel allele of J, the ortholog of Arabidopsis thaliana EARLY FLOWERING 3 (ELF3). The mutant allele e6PG, which carries a Ty1/Copia-like retrotransposon insertion, does not suppress the legume-specific flowering repressor E1, allowing E1 to inhibit Flowering Locus T (FT) expression and thus delaying flowering and increasing yields under SD conditions. The e6PG allele is a rare allele that has not been incorporated into modern breeding programs. The dysfunction of J might have greatly facilitated the adaptation of soybean to low latitudes. Our findings increase our understanding of the molecular mechanisms underlying the LJ trait and provide valuable resources for soybean breeding. 相似文献
15.
Twelve species of the harpacticoid genus Elaphoidella, most of them exclusively groundwater species, have been recorded in Slovenia (SE Europe). Their distribution and ecology are reviewed with the aim of evaluating distribution patterns, species preferences for groundwater habitats, ecological preferences and interactions with other copepod species at regional scale. Data on Elaphoidella species were obtained partly from the existing literature and partly from the author's (AB) own sampling campaigns carried out together with his co-workers. During the rich history of collecting copepods in Slovenia (from the 1920s to present), Elaphoidella species were recorded at 78 sampling sites altogether. The majority of collecting was conducted in the southern (Dinaric region) and north-western (Alpine region) Slovenia. The most intensively sampled habitats were porous aquifers of alluvial plains, springs in the karstic unsaturated zone and percolation water in caves. The highest species richness of Elaphoidella was recorded in the southern Slovenia, where 10 species were found. The strictly “Dinaric” species are E. charon, E. franci, E. karstica, E. stammeri, E. sp. 1 and E. sp. 2, while E. phreatica and E. bidens were found exclusively in the north-western Slovenia. From the latest data on the copepod distributions (2002–2004), where the environmental characteristics of sampling sites were also measured, the relationship between selected environmental characteristics of the habitats and the presence of Elaphoidella species was analysed. The distribution of Elaphoidella species in Slovenia was found to be related with the region, habitat type, altitude, conductivity and pH of the water. 相似文献
16.
Kaiming Ye Sha Jin Kelly Bratic Jerome S. Schultz 《Journal of Molecular Catalysis .B, Enzymatic》2004,28(4-6):201-206
Glucose binding protein (GBP) from Escherichia coli has been widely used to develop minimally invasive glucose biosensors for diabetics. To develop a cell-based glucose biosensor, it is essential to functionally display GBP on the cell surface. In this study, we designed a molecular structure to display GBP on the outer membrane of E. coli. We fused GBP with the first nine N-terminal residues of Lpp (major E. coli lipoprotein) and the 46–150 residues of OmpA (an outer membrane protein of E. coli). With this molecular design, we have successfully displayed GBP on the surface of E. coli. Using FITC-conjugated Dextran, we demonstrated that glucose’s binding sites of surface-displayed GBP were accessible to glucose. Furthermore, we showed that glucose transport in a GBP-deficient E. coli NM303 could be restored by displaying GBP on the surface of NM303. 0.51 h−1 of specific growth rate was attained for NM303/pESDG grown in M9 minimal medium supplemented with 2 g/l glucose, whereas no growth was observed for NM303 in the same medium. Both NM303 and NM303/pESDG grew in M9 medium supplemented with 1 mM of fucose. Because cell surface is an interface between intracellular and extracellular molecular events, this technique paves a way to develop cell-based glucose biosensors. 相似文献
17.
胡颓子属5种植物果实主要类胡萝卜素成分及含量 总被引:1,自引:0,他引:1
利用高效液相色谱法对华东地区常见的胡颓子属(Elaeagnus) 4种生态型的胡颓子(E. pungens)、2个变种的大叶胡颓子(E. macrophylla)、蔓胡颓子(E. glabra)、银果胡颓子(E. magna)和佘山胡颓子(E. argyi) 9个样品成熟果实所含主要类胡萝卜素成分及含量进行了检测。结果表明, 5种胡颓子属植物成熟果实中的主要类胡萝卜素成分为番茄红素, 且在不同种间含量差异显著, 含量最高的是浙江嵊州的胡颓子, 其值为(259.89±26.22) µg·g-1FW, 最低的是佘山胡颓子, 其含量为(91.19±7.74) µg·g-1FW; 其中4种生态型的胡颓子的番茄红素含量都较高。研究表明这5种胡颓子属植物果实富含番茄红素, 是一类珍贵的天然番茄红素资源, 具有较大的市场开发应用价值。研究结果为揭示果实高积累番茄红素的机理提供了理想的研究材料。 相似文献
18.
To investigate the molecular basis of zymodeme analysis in the enteric protozoan parasite Entamoeba histolytica, genes encoding glucose phosphate isomerase (GPI) were isolated from four representative E. histolytica strains belonging to zymodeme II, II-, XIV, or XIX. Two alleles were obtained from each strain; six alleles with eight polymorphic nucleotide positions were identified among the four strains. Two of these eight polymorphic nucleotides resulted in non-conserved amino acid substitutions. Three GPI isoenzymes with distinct predicted isoelectric points were identified, which agrees well with the observed electrophoretic patterns of GPI from these strains. Amino acid comparisons of GPI from E. histolytica and other organisms revealed that all amino acid residues implicated for substrate binding and catalysis were conserved. Biochemical characterization of recombinant E. histolytica GPI confirmed that it possessed kinetic parameters similar to GPI from other organisms. The electrophoretic mobility of three GPI isoenzymes was examined by starch gel electrophoresis. Thus, we have established the molecular basis of the classical isoenzymes patterns that have been used for grouping E. histolytica isolates and for differentiation of E. histolytica from non-pathogenic Entamoeba dispar. 相似文献
19.
尾巨桉愈伤组织的生长分化受内源激素影响,而miRNA396是一个调控植物叶片与根系生长发育的小RNA,与细胞分裂素的合成相关,CKX是负责调控细胞分裂素的氧化酶基因。为探讨miRNA396与CKX基因对尾巨桉愈伤组织生长发育的调控作用,以尾巨桉基因组为模板,进行PCR扩增及测序分析尾巨桉基因中的miRNA396序列,用不同PBU细胞分裂素浓度培养下的尾巨桉愈伤组织RNA逆转录的cDNA为模板,通过荧光定量PCR,测定不同PBU浓度处理的尾巨桉愈伤组织中miRNA396及CKX的表达差异。结果表明,相对于0.5 mg·L(-1)PBU处理的桉树愈伤组织,1 mg·L(-1)PBU处理的桉树愈伤组织miRNA396及CKXA、CKXB和CKXF表达量显著下调,差异达到极显著水平,CKXC、CKXD和CKXE均上调,但只有CKXC相对表达量达到极显著水平;2 mg·L(-1)PBU处理的尾巨桉愈伤组织miRNA396A、CKXD、CKXE和CKXF表达量均下调,差异达到极显著水平,其他CKX表达量均上调,CKXA相对表达量差异... 相似文献
20.
Steven L. Goldberg Venkata B. Nanduri Linda Chu Robert M. Johnston Ramesh N. Patel 《Enzyme and microbial technology》2006,39(7):1441-1450
The enantioselective microbial reduction of 6-oxo-8-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-8-azaspiro[4.5]decane-7,9-dione (1) to either of the corresponding (S)- and (R)-6-hydroxy-8-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-8-azaspiro[4.5]decane-7,9-diones (2 and 3, respectively) is described. The NADP+-dependent (R)-reductase (RHBR) which catalyzes the reduction of 6-ketobuspirone (1) to (R)-6-hydroxybuspirone (3) was purified to homogeneity from cell extracts of Hansenula polymorpha SC 13845. The subunit molecular weight of the enzyme is 35,000 kDa based on sodium dodecyl sulfate gel electrophoresis and the molecular weight of the enzyme is 37,000 kDa as estimated by gel filtration chromatography. (R)-reductase from H. polymorpha was cloned and expressed in Escherichia coli. To regenerate the cofactor NADPH required for reduction we have cloned and expressed the glucose-6-phosphate dehydrogenase gene from Saccharomyces cerevisiae in E. coli. The NAD+-dependent (S)-reductase (SHBR) which catalyzes the reduction of 6-ketobuspirone (1) to (S)-6-hydroxybuspirone (2) was purified to homogeneity from cell extracts of Pseudomonas putida SC 16269. The subunit molecular weight of the enzyme is 25,000 kDa based on sodium dodecyl sulfate gel electrophoresis. The (S)-reductase from P. putida was cloned and expressed in E. coli. To regenerate the cofactor NADH required for reduction we have cloned and expressed the formate dehydrogenase gene from Pichia pastoris in E. coli. Recombinant E. coli expressing (S)-reductase and (R)-reductase catalyzed the reduction of 1 to (S)-6-hyroxybuspirone (2) and (R)-6-hyroxybuspirone (3), respectively, in >98% yield and >99.9% e.e. 相似文献