Synaptic integration mediated by striatal cholinergic interneurons in basal ganglia function

The physiological role of striatal cholinergic interneurons was investigated with immunotoxin-mediated cell targeting (IMCT). Unilateral cholinergic cell ablation caused an acute abnormal turning behavior. These mice showed gradual recovery but displayed abnormal turning by both excess stimulation and inhibition of dopamine actions. In the acute phase, basal ganglia function was shifted to a hyperactive state by stimulation and suppression of striatonigral and striatopallidal neurons, respectively. D1 and D2 dopamine receptors were then down-regulated, relieving dopamine-predominant synaptic perturbation but leaving a defect in controlling dopamine responses. The acetylcholine-dopamine interaction is concertedly and adaptively regulated for basal ganglia synaptic integration.     

MRI诊断双侧基底节区对称性分水岭脑梗死

目的：探讨双侧基底节区对称性分水岭性脑梗死(CWI)的病因与机理、MRI特征。方法：回顾性分析12例经MRI及临床证实的双侧基底节区对称性CWI的临床资料及MRI表现。结果：12例的病因中以严重低血压及低血容量为主，MRI表现为双侧基底节区对称性T1WI为低，T2WI为高信号，信号均匀，占位不明显，加强扫描无强化。结论：双侧基底节区对称性CWI病因主要为严重低血压及低血容量。MRI能较早及敏感地显示其变化，其与一些好发于基底节区病变的MRI表现相似，鉴别时须结合临床资料。     

Hydra viridis: inhibition by the basal disk of basal disk differentiation

When the basal dist of Hydra viridis is excised, a new disk is regenerated. A basal disk grafted on an animal regenerating its own disk can suppress this regeneration. The effect is reversed if the grafted basal disk is subsequently excised. For inhibition to occur, the grafted disk must be present for at least 3 hours, beginning no later than 2 hours after amputation. The results indicate that the basal disk participated in the control of its own differentiation.     

Isolation and propagation of a human enteric coronavirus

Coronavirus-like particles were found by electron microscopy in stools from infants with necrotizing enterocolitis. Stool samples from these infants as well as control specimens were passaged in cultures of human fetal intestinal organs. Two samples yielded virus-like particles and these have now been passaged 14 times (HEC 14). Gradient-purified HEC 14 strains had typical coronavirus morphology on electron microscopy and contained five major proteins with molecular sizes ranging from 190 to 23 kilodaltons. Infants with necrotizing enterocolitis developed specific antibody to the viral antigens between the acute and convalescent stages of the disease, as shown by examining serum specimens by single radial hemolysis, immunoenzymatic assay, and Western immunoblotting. No cross-reactivity was shown with other coronavirus strains tested, or with the newly isolated viruses of the Breda-Berne group, responsible for calf or horse diarrhea.     

Preganglionic stimulation increases calcium uptake by sympathetic ganglia

Isolated superior cervical ganglia of rats accumulate more calcium during preganglionic stimulation than do unstimulated controls; uptake of calcium-45 is approximately doubled by stimulation of 12 impulses per second. The extra uptake is markedly reduced by a high concentration of magnesium, but not by mecamylamine hydrochloride or tetraethylammonium chloride, although all three agents eliminate the postsynaptic action potential. Uptake of calcium-45 is also greatly increased by a high external concentration of potassium.     

The Genome sequence of the SARS-associated coronavirus

We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)-associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.     

Archaefructaceae, a new basal angiosperm family

Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants. This family consists of the fossils Archaefructus liaoningensis and A. sinensis sp. nov. Complete plants from roots to fertile shoots are known. Their age is a minimum of 124.6 million years from the Yixian Formation, Liaoning, China. They are a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis. Their reproductive axes lack petals and sepals and bear stamens in pairs below conduplicate carpels.     

Characterization of a novel coronavirus associated with severe acute respiratory syndrome

In March 2003, a novel coronavirus (SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS). The sequence of the complete genome of SARS-CoV was determined, and the initial characterization of the viral genome is presented in this report. The genome of SARS-CoV is 29,727 nucleotides in length and has 11 open reading frames, and its genome organization is similar to that of other coronaviruses. Phylogenetic analyses and sequence comparisons showed that SARS-CoV is not closely related to any of the previously characterized coronaviruses.     

Parasympathetic ganglia: activation of an adrenergic inhibitory mechanism by cholinomimetic agents

Electrical stimulation of the sympathetic nerves to the urinary bladder or the intraarterial administration of the cholinomimetic substances acetylcholine or methacholine produced adrenergic inhibition in parasympathetic ganglia on the surface of the bladder. The inhibition appeared to be mediated, at least in part, via adrenergic inhibitory neurons located in the pelvic plexus. Atropine blocked the inhibitory response to injected cholinomimetic agents but did not alter the response to stimulation of the sympathetic nerves. Thus, the inhibitory neurons can be activated via both muscarinic and nonmuscarinic receptors, the latter being of primary physiological importance.     

Correction of murine beta-thalassemia by gene transfer into the germ line

A murine beta-thalassemia was corrected by the transfer of cloned beta-globin genes into the mouse germ line. The cloned mouse beta maj-globin gene or the cloned human beta-globin gene was introduced into mice deficient in beta-globin synthesis because of a deletion of the beta maj-globin gene. Both introduced genes produced functional beta-globin chains, leading to a reduction in one case, and elimination in another case, of the anemia and associated abnormalities of the red blood cells.     

利用小鼠模型的脲酶免疫刺激物效果评价

建立小鼠模型对制备的脲酶免疫刺激物进行免疫效果及其安全性评价。利用IPTG诱导脲酶基因克隆菌,大量表达脲酶UreB蛋白,用SDS-PAGE及Bradford方法对表达产物进行定性和定量分析;将脲酶UreB蛋白与弗氏(不)完全佐剂混合并乳化,制备成脲酶免疫刺激物。选择健康昆明小白鼠40只,随机分为4组,分别注射脲酶免疫刺激物、弗氏(不)完全佐剂和生理盐水,同时设置非注射为空白对照。利用间接ELISA测定特异性抗体效价,利用血常规分析仪和流式细胞仪测定小鼠血常规。结果表明:构建克隆菌株可以大量表达脲酶B蛋白,质量浓度为0.39 mg/mL。小鼠血清中特异性IgG抗体效价能达到1∶10 000以上,显著高于其他3个对照组(P<0.05),而特异性抗体IgA和IgM效价与对照组比较差异不显著(P>0.05)。脲酶免疫刺激物能显著提高小鼠血中白细胞、淋巴细胞和中间细胞数及比例(P<0.05),而对血液其他指标没有显著影响(P>0.05)。本试验成功制备脲酶免疫刺激物,并能有效刺激机体免疫应答,为后期奶牛免疫试验打下基础。     

细胞自噬在冠状病毒感染中作用机制的研究进展

细胞自噬在病毒感染和致病过程中具有重要作用。针对目前冠状病毒在全世界传播尤其是严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)引发的新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)危害人类健康的现状,综述了冠状病毒和细胞自噬的研究进展,分析了细胞自噬与病毒感染之间的关系,包括细胞自噬抑制及促进病毒感染的作用,重点探讨了冠状病毒诱导细胞发生自噬、细胞自噬影响冠状病毒的复制以及冠状病毒调控细胞自噬的分子作用机制3个方面,最后对靶向细胞自噬防控冠状病毒的感染与传播进行了展望,不仅有助于了解冠状病毒的致病机制,而且为抗病毒药物和疫苗的研发提供理论基础,从而为冠状病毒的防控提供新思路。     

Ouabain resistance conferred by expression of the cDNA for a murine Na+, K+-ATPase alpha subunit

The molecular basis for the marked difference between primate and rodent cells in sensitivity to the cardiac glycoside ouabain has been established by genetic techniques. A complementary DNA encoding the entire alpha 1 subunit of the mouse Na+- and K+-dependent adenosine triphosphatase (ATPase) was inserted into the expression vector pSV2. This engineered DNA molecule confers resistance against 10(-4) M ouabain to monkey CV-1 cells. Deletion of sequences encoding the carboxyl terminus of the alpha 1 subunit abolish the activity of the complementary DNA. The ability to assay the biological activity of this ATPase in a transfection protocol permits the application of molecular genetic techniques to the analysis of structure-function relationships for the enzyme that establishes the internal Na+/K+ environment of most animal cells. The full-length alpha 1 subunit complementary DNA will also be useful as a dominant selectable marker for somatic cell genetic studies utilizing ouabain-sensitive cells.     

Substance P: a putative sensory transmitter in mammalian autonomic ganglia

Repetitive presynaptic stimulation elicited slow membrane depolarization in neurons of inferior mesenteric ganglia from guinea pigs. This response was not blocked by cholinergic antagonists but was specifically and reversibly inhibited by a substance P analog, (D-Pro2, D-Phe7, D-Trp9)-substance P, which also depressed the depolarization induced by exogenously applied substance P. The atropine-sensitive slow excitatory and slow inhibitory postsynaptic potentials evoked in neurons of rabbit superior cervical ganglia were not affected by the substance P analog. These and previous results provide strong support for the hypothesis that substance P or a closely related peptide is the transmitter mediating the slow depolarization. The latter may represent a sensory input from the gastrointestinal tract to neurons of the prevertebral ganglia.     

IBV感染鸡气管黏膜上皮基底细胞特性研究

【目的】研究IBV感染鸡气管黏膜上皮细胞(Chicken trachea epithelium cells,CTECs)中基底细胞的特性,以进一步揭示IBV感染与α-2,3-唾液酸受体之间的关系。【方法】利用光学显微镜观察、电子显微镜技术、RTPCR方法,对接种IBV的细胞进行观察和检测,研究IBV对基底细胞的感染特征。【结果】与CTECs感染IBV结果相反,单独培养的基底细胞接种IBV后,无明显的形态学损伤和亚细胞结构(溶酶体、细胞核)的损伤,细胞中也检测不到IBV的增殖。【结论】气管黏膜上皮细胞可以被IBV感染,单独的基底细胞不能被IBV感染,提示α-2,3-唾液酸受体是否存在与IBV感染具有重要的关系。