Growth and Grazing Rates of the Marine Planktonic Ciliate Strombidinopsis sp. on Red-Tide and Toxic Dinoflagellates

ABSTRACT We investigated growth and grazing rates of Strombidinopsis sp. when feeding on several species of red-tide and/or toxic dinoflagellates. Strombidinopsis sp. one of the largest aloricate choreotrichs so far reported, grew well on Lingulodinium polyedrum, Gymnodinium sanguineum, Scrippsiella trochoidea, Cochlodinium polykrikoides , and Prorocentrum minimum , but failed to grow on Amphidinium carterae. Specific growth rates of Strombidinopsis sp. increased rapidly with increasing prey density up to ca. 100 ng C ml^-1, but were saturated or increased slightly at higher concentrations. Maximum specific growth rates of Strombidinopsis sp. on various prey species were 1.38 day^-1 for C. polykrikoides , 1.27 for G. sanguineum , 1.06 for P. minimum , 0.83 for L. polyedrum , and 0.67 for S. trochoidea. Threshold prey concentrations (where net growth = 0) were 12–38 ng C ml^-1. Maximum ingestion and clearance rates of Strombidinopsis sp. were 353 ng C grazer^-1 day^-1 and 110 μ, l grazer^-1 h^-1, respectively. Strombidinopsis sp. exhibited higher maximum growth, ingestion, and clearance rates than the mixotrophic dinoflagellate Fragilidium cf. mexicanum or the heterotrophic dinoflagellates Protoperidinium cf. divergens and P. crassipes , when grown on the same prey species. In addition, the sequence of prey species arranged according to growth response of Strombidinopsis sp. differed considerably from those of Fragilidium cf. mexicanum, Protoperidinium cf. divergens , and P. crassipes.     

血管生成系及其相关蛋白的研究进展

对血管生成素及其相关蛋白的研究进展和分子生物学特性进行了综述,迄今,已经发现了4种血管生成素及某些血管生成素的同工蛋白或变异体。这些蛋白质具有共同的结构,即氨基端与分泌相关的信号肽,介导同源寡聚体形成的螺旋样结构域,和羧基末端介导配体活性的纤维蛋白原样结构域。血管生成素均可与Tie-2受体结合,但只有血管生成素1和4可激活Tie-2受体。血管生成素1和4为效应剂而血管生成素2和3为拮抗剂。对于血管生成素是否可与Tie-1结合尚不清楚。血管生成素相关蛋白具有公认的血管生成素的特征性结构,对其功能及其作用途径还不十分了解,有待于进一步研究。Tie-1和Tie-2的其他配体以及血管生成素相关蛋白类似物的特异受体有可能在今后得到阐明。     

Isolation of 15 polymorphic microsatellite loci in Acacia hybrid (Acacia mangium×Acacia auriculiformis)

This study reports the isolation of 15 microsatellites in Acacia hybrid (Acacia mangium×Acacia auriculiformis) based on the 5′ anchored polymerase chain reaction technique. Polymorphism of these loci was evaluated in a sample of 24 hybrid individuals. The level of polymorphism ranged from two to eight alleles with an observed heterozygosity ranging from 0.083 to 0.875. These loci were also characterized in both the parental species. The number of alleles ranged from two to six for both A. mangium and A. auriculiformis with the observed heterozygosity values ranging from 0.167 to 0.625 and 0.042 to 0.458 respectively. Five of these loci demonstrated Mendelian inheritance in a segregating F₁ population; four presented a distorted ratio and the remaining six did not segregate in progenies as they were homozygous in both parents.