A MORPHOLOGICAL AND TAXONOMIC CONSIDERATION OF TABELLARIA (BACILLARIOPHYCEAE) FROM THE NORTHCENTRAL UNITED STATES1,2

The taxonomy, distribution, and ecology of the diatom genus Tabellaria Ehr. from a portion of the northcentral United States were studied from collections made from August 1968 to October 1971. Using the transmission electron microscope with carbon replicas of the frustule surfaces, taxonomically significant characters were identified and related to those visible with the light microscope, four morphologically distinguishable taxa were recognized. The frustular morphology of T. fenestrata (Lyngbye) kütz. em. Knudson var. fenestrata was confirmed by both light and electron microscopy. T. flocculosa (Roth) Kütz. var. flocculosa is composed of 3 morphologically distinguishable strains. One of which is sufficiently different from the nominate variety to be described as T. flocculosa var. linearis var. nov. Also, a planktonic ecotype of one of the strains was identified.     

MORPHOMETRIC ANALYSIS OF POLLEN FROM FOUR SPECIES OF AMBROSIA (COMPOSITAE)

A morphometric approach proved useful for characterizing pollen from the Ambrosia species that are responsible for most ragweed hayfever and for correctly identifying individual pollen grains. Pollen was harvested from 4 species (A. trifida, A. artemisiifolia, A. bidentata, A. psilostachya) grown in Champaign County, Illinois, and observed with a scanning electron microscope. Quantitative measurements of 6 different exine characters were made on micrographs of 96 pollen grains from each species. Discriminant analysis based on these characters was used to obtain a population centroid for each species and indicated that these centroids were distinctly different. This analysis also included a species classification for individual pollen grains and indicated probability of species membership. About 86% of all individuals were correctly classified when the 4 species were included, with a range from 80% (A. artemisiifolia) to 95% (A. psilostachya). When three species (A. trifida, A. artemisiifolia, A. bidentata) were analyzed, about 87% of the individuals were correctly classified, and almost all individuals (97%) were classified correctly when only A. trifida and A. artemisiifolia were included. The validity of the derived discriminant functions was also tested by treating herbarium specimens as unknowns. The species and percentages of these individuals correctly classified were A. trifida (100%), A. artemisiifolia (58%), A. bidentata (100%), and A. psilostachya (31%). The classification results using three species were A. trifida (100%), A. artemisiifolia (75%), and A. bidentata (100%); and using two species were A. trifida (100%) and A. artemisiifolia (92%). Hence, the disciminant functions do seem valid for 3 species, but further investigation of A. psilostachya is needed. This type of approach may be useful in pollen analysis, especially where these species significantly contributed to aeroallergens.     

麂属动物陈旧皮张标本的DNA提取及PCR扩增

本实验用改进的方法从保存于标本馆的动物皮张标本中提取ＤＮＡ,所得ＤＮＡ片段的分子量从１００ｂｐ到１ｋｂ以上。利用线粒体ＤＮＡ细胞色素ｂ通用引物和ＰＣＲ技术,从小麂、印度麂、贡山麂、费氏麂、黑麂ＤＮＡ中扩增出３０７ｂｐ的细胞色素ｂ特异片段。用２８种限制性内切酶对从新鲜血样和从陈旧皮张标本中所得扩增片段进行酶切分析,发现只有４个酶在这个片段上有切点,其中ＨａｅⅢ和ＨａｐⅡ的识别位点在各种麂中有所不同。     

ADDITIONAL SPECIMENS OF SUDAMERICID (GONDWANATHERIA) MAMMALS FROM THE EARLY PALEOCENE OF ARGENTINA

Abstract: The extinct, Cretaceous–Paleogene Gondwanatherians have previously been considered to be early xenarthrans, multituberculates and more recently Mammalia incertae sedis. However, the phylogenetic relationships of Gondwanatheria have yet to be resolved. In this paper, additional dental specimens of the gondwanatherian Sudamerica ameghinoi from the Early Paleocene Salamanca Formation of Argentina are described. These specimens provide additional information on Gondwanatheria affinities, sudamericid morphology and help support earlier hypotheses on Sudamerica dental formula and tooth categories. Sudamericid dental functional morphology and body mass estimates, based on measurements of isolated teeth, are inferred. Dental morphology such as hypsodonty, enamel microstructure and crown features do support a robust clade for Sudamericidae.     

RIMOPORTULAE IN EUPODISCUS RADIATUS (BACILLARIOPHYCEAE) FROM THE NORTHEASTERN GULF OF MEXICO1

Specimens of Eupodiscus radiatus Bailey from the northeastern Gulf of Mexico were examined with light and scanning electron microscopy. In contrast to previous studies of this taxon, we report the presence of two, rarely one, rimoportulae (labiate processes) between consecutive ocelli. This finding changes our understanding of the phylogenetic relationships in the family Eupodiscaceae.     

银鲳分类鉴别及新模标本指定

银鲳为我国重要海洋渔业资源之一,被认为广泛分布于中国沿海以及印度-西太平洋海域.1788年,Euphrasen 基于在中国广东虎门采集的1尾标本首次对银鲳进行描述,后来被世界众多学者报道.由于Euphrasen当初描述银鲳时缺乏重要的形态鉴别特征,加之其模式标本存放地点至今不详,因此导致银鲳的分类鉴定和命名出现许多错误和混乱,有必要对其澄清.2011年4月至2012年5月,作者在银鲳模式标本产地广东虎门和珠海共采到19尾鲳属鱼类标本,经鉴定与Euphrasen在1788年对银鲳的描述及附图十分吻合.因此,本文对银鲳进行重新描述,并指定其中1尾标本为新模标本.     

FLOW CYTOMETRIC ANALYSIS OF SPERMATOGENESIS IN THE DIATOM THALASSIOSIRA WEISSFLOGII (BACILLARIOPHYCEAE)1

Flow cytometry was used to detect and quantify sexual differentiation in the centric diatom Thalassiosira weissflogii (Grun.). Size (light scatter), chlorophyll, protein and DNA contents were measured for each cell throughout the process of differentiation. Male gametes were small round cells characterized by one complement of DNA and a lower protein and chlorophyll content than vegetative cells. Male gamete formation was induced by a long period of darkness (2 days) followed by a transfer to continuous light. Up to 30% of the initial cell population produced male gametes which appeared in the culture 14 h after release from darkness. Male gamete production was also detected in exponentially growing cultures in continuous light, but to a much smaller degree.     

FLOW CYTOMETRIC ANALYSIS OF SPERMATOGENESIS IN THE DIATOM THALASSIOSIRA WEISSFLOGII (BACILLARIOPHYCEAE)1

Flow cytometry was used to detect and quantify sexual differentiation in the centric diatom Thalassiosira weissflogii (Grun.). Size (light scatter), chlorophyll, protein and DNA contents were measured for each cell throughout the process of differentiation. Male gametes were small round cells characterized by one complement of DNA and a lower protein and chlorophyll content than vegetative cells. Male gamete formation was induced by a long period of darkness (2 days) followed by a transfer to continuous light. Up to 30% of the initial cell population produced male gametes which appeared in the culture 14 h after release from darkness. Male gamete production was also detected in exponentially growing cultures in continuous light, but to a much smaller degree.     

CHARACTERIZATION OF A cDNA ENCODING GLUTAMINE SYNTHETASE FROM THE MARINE DIATOM SKELETONEMA COSTATUM (BACILLARIOPHYCEAE)

A cDNA-encoding glutamine synthetase (GS) was isolated from the marine diatom Skeletonema costatum (Greville) Cleve by PCR amplification. Nucleic acid and deduced amino acid sequences of the diatom GS were greater than 50% identical to GS from green algae and vascular plants, and phylogenetic analysis established the diatom GS as a member of the GSII gene family. The presence of an N-terminus signal sequence, identified on the basis of sequence similarity with other chloroplast-localized proteins from diatoms, suggests that the encoded GS isoenzyme is localized to the chloroplast. The GS mRNA was present in log-phase cells grown with either nitrate or ammonium as the sole added nitrogen source. Results from Southern blot analysis of genomic DNA suggested that the cDNA isolated in this study was either a member of a small, highly conserved gene family or that there was allelic variation within the region examined. Phylogenetic analyses further indicated that genes encoding GS from the diatom and two species of green algae diverged prior to the gene duplication, to the isoenzymes in vascular plants, supporting the hypothesis that GS isoenzymes in diatoms, green algae, and vascular plants arose through independent evolutionary events.     

ULTRASTRUCTURE OF THE FRUSTULE OF TRICERATIUM FAVUS (BACILLARIOPHYCEAE)1,2

New structural details of the frustules of the diatom Triceratium favus Ehrenberg seen in the scanning electron microscope are reported. Significant new observations concern the pores of the hexagonal chambers, accessory structures (spines, dendritic processes) on the outer surfaces of the hexagonal chambers, the value margins and girdle structure.     

膜翅目昆虫干标本的基因组DNA提取

提出了膜翅目昆虫干标本基因组DNA的提取方法,通过对实验结果和所测得的基因片段（28S D2 rDNA)的分析,表明该方法可行。     

副沙鳅属的多变量形态分析

采用多变量分析方法对副沙鳅属Parabotia的外部形态进行了主成分分析,在27个测量性状的第1、第2主成分散布图上显示,副沙鳅属的外部形态存在着3个具有明显差异的种组:即点面副沙鳅,双斑副沙鳅、武昌副沙鳅和花斑副沙鳅,漓江副沙鳅和小副沙鳅3个种组.主成分负荷值还进一步表明,6种副沙鳅属外部度量性状的差异有多元化的倾向.结合定性特征的观察确定了副沙鳅属6个种的有效性.     

肝细胞癌及相关病变的计算机图像定量分析

为研究肝炎、肝硬变与肝细胞癌的关系,利用自动图像分析仪对６４例肝炎、肝硬变、癌旁肝硬变、肝细胞癌和正常肝组织进行了十三项参数的形态定量研究。结果：大多数参数随病变的发展而呈规律性变化,癌旁肝硬变的多数参数介于不伴肝癌的肝硬变与肝细胞癌之间。提示：（１）慢活肝、肝硬变与肝细胞癌密切相关;（２）癌旁肝硬变不同于不伴肝癌的肝硬变,与肝细胞癌的关系更密切。利用逐步判别分析选择出六项参数建立判别函数方程,回代正确率为９８．２％。     

THE GLUCOSE TRANSPORT SYSTEM OF AMPHORA COFFEAEFORMIS (BACILLARIOPHYCEAE)1

Amphora coffeaeformis (Ag.) Kütz. var. perpusilla (Grun.) Cleve took up glucose by an inducible transport system. The system was induced by d -fructose, d -mannose, as well as glucose. Some d -pentoses also induced a glucose uptake system but it may not be the same one as that induced by hexose. d -fructose, d -mannose and 2-deoxy-d -glucose inhibited 2 mM glucose uptake at equimolar concentration, but d -pentoses did not. The uptake system decayed in ca. 5 h in the absence of glucose. The half-saturation constant for uptake, K₈ was ca. 0.1 mM glucose with a maximum uptake rate, V_max= 0.4 nmol/10⁶ cells-min^?1.