恶性疟原虫abstrakt同源基因的克隆及DEAD盒家族蛋白的序列分析

DEAD盒蛋白家族的ATP依赖性的RNA解旋酶类参与细胞内几乎所有的RNA代谢过程 ,在几乎所有生物的细胞生长发育过程中扮演着众多不可或缺的角色。在本实验中 ,通过PCR和探针杂交相结合的筛选方法 ,筛选恶性疟原虫 (Plasmodiumfalciparum)的基因组文库 ,克隆了FH1F———abstrakt同源基因的完整序列。通过搜索已经完成测序的恶性疟原虫基因组数据库 ,推测FH1F序列定位在第 5条染色体上。FH1F全长2 80 4bp,包含一个 1 1 6 1bp的完整阅读框 ,编码一个由 386个氨基酸组成的蛋白。对FH1F蛋白序列用BlastP进行搜索和分析以及用DNAStar与许多典型的DEAD盒蛋白序列进行比对分析 ,结果均提示FH1F蛋白应该是DEAD盒家族的一个Abstrakt蛋白。另一方面 ,用DNAStar对已知所有完整的DEAD盒蛋白进行详细的序列分析以及用Mega对这些序列进行系统发育研究的结果都显示 :DEAD盒家族的蛋白聚类成为若干不同的亚群 ;与DEAD盒蛋白的一般保守序列相比 ,Abstrakt,eIF 4A ,Vasa ,P6 8等不同亚群的DEAD盒蛋白在保守区具有各自不同的结构特征。本文对不同的DEAD盒蛋白的结构特征进行了总结并试图给出不同亚群分类上的结构标准 ,对Abstrakt蛋白在本应高度保守的位点上异常于其它DEAD盒蛋白的氨基酸残基的取代也进行了相关的初步分析     

Understanding Animal Companion Surplus in the United States: Relinquishment of Nonadoptables to Animal Shelters for Euthanasia

Relinquishing a nonhuman animal to a shelter is a complex decision that, it is often believed, ultimately may represent a breakdown of the human-animal bond. The result of such a breakdown is an animal companion surplus in the United States, which is no better evidenced than by the statistics documenting the millions of animals euthanized at shelters every year. This research examined the companion animals who are relinquished by their owners to shelters for adoption and compared them specifically to those relinquished for euthanasia. The study also compared the owner characteristics of the animals in these two groups. Although the majority of dogs and cats relinquished are clearly adoptable, a sizable number of these pets presented to shelters for euthanasia have problems precluding their adoptability: old age, illness, and refractory behavior.     

The genus Neurosema (Psocoptera, Calopsocidae) from New Guinea

Abstract Three species of Neurosema are recognized: N.apicalis McLachlan (redescribed, lectotype designated), N. sp. ( N.apicalis sensu Enderlein – mis-identification) and N.pulchra sp.n., and a key to these is given. Separation of genera in the Calopsocidae is briefly discussed.     

Inductive interactions in early embryonic development.

This is an update of a previous review (Current Opinion in Cell Biology 2:969-974) in which we discussed recent work attempting to understand the sequence of inductive interactions responsible for establishing the body plan of the early embryo. As before, we concentrate on inductive interactions in amphibian embryos, where significant progress has been made in the past two years. In this update, however, we also consider recent embryological data obtained with amniote embryos such as the chick, together with complementary data provided by genetic analyses of mouse and Drosophila development.     

Medullary electrosensory processing in the little skate

1. Previous studies have demonstrated that the resting activity of electrosensory ALLN fibers is modulated by the animal's own respiratory activity and that all fibers innervating a single ampullary cluster are modulated with the same amplitude and phase relationship to ventilation. We demonstrate that ALLN fibers in the skate are modulated in this common-mode manner bilaterally, regardless of receptor group, orientation, or position of the receptor pore on the body surface (Fig. 2). 2. Ascending efferent neurons (AENs), which project to the electrosensory midbrain from the DON, are modulated through a much smaller portion of their dynamic range. AENs give larger responses to an extrinsic local electric field than to the respiratory driving, indicating that a mechanism exists for suppressing ventilatory electrosensory reafference. 3. In paralyzed animals no modulation of resting activity or of responses of extrinsic electric fields could be observed with respect to the animal's respiratory motor commands in the absence of electrosensory reafference. 4. Cells of the dorsal granular ridge (DGR) project to medullary AENs via the DON molecular layer. A majority of proprioceptive DGR neurons are modulated by ventilatory activity, however, in a given fish the modulation is not in the same phase relationship to ventilation among DGR units. 5. The modulation of AENs during respiration was increased following transection of the contralateral ALLN (Fig. 9). Resting activity and responses to excitatory stimuli were inhibited by simultaneous stimulation of the transected contralateral ALLN indicating that a common-mode rejection mechanism is mediated via the commissural interconnections of the DONs.