利用恒河婴猴模型对肠道病毒71型传播感染特征的生物学分析

本文在前期工作基础上,进一步对肠道病毒71型(EV71)从恒河婴猴的感染个体向其他未感染个体传播的可能性及相关生物学特性做了初步分析.通过喷雾形式经呼吸道感染1~2月龄恒河婴猴(A组);在观察临床症状同时,于感染后第7天,取该组动物粪便处理后,将上清液以喷雾形式经呼吸道感染新的婴猴个体(B组),随后对该次代感染个体进行...     

基于Voronoi图的丹顶鹤巢址空间格局分析

依据1996年、2003—2007年扎龙保护区丹顶鹤巢址数据,利用Voronoi图理论,分析了巢址的空间分布特征,计算了其拓扑指数—Voronoi图面积。结果表明,丹顶鹤巢址空间分布具有明显的空间聚类特征。以扎龙保护区的2006年巢址、居民点、国道和铁路为对象,构成其Voronoi图,较好地说明了人类活动对丹顶鹤巢址的空间格局的影响,研究结果对丹顶鹤栖息地的保护将起到重要作用。     

Anti-Apoptotic Protein Bcl-xL Expression in the Midbrain Raphe Region Is Sensitive to Stress and Glucocorticoids

Anti-apoptotic proteins are suggested to be important for the normal health of neurons and synapses as well as for resilience to stress. In order to determine whether stressful events may influence the expression of anti-apoptotic protein Bcl-xL in the midbrain and specifically in the midbrain serotonergic (5-HT) neurons involved in neurobehavioral responses to adverse stimuli, adult male rats were subjected to short-term or chronic forced swim stress. A short-term stress rapidly increased the midbrain bcl-xl mRNA levels and significantly elevated Bcl-xL immunoreactivity in the midbrain 5-HT cells. Stress-induced increase in glucocorticoid secretion was implicated in the observed effect. The levels of bcl-xl mRNA were decreased after stress when glucocorticoid elevation was inhibited by metyrapone (MET, 150 mg/kg), and this decrease was attenuated by glucocorticoid replacement with dexamethasone (DEX; 0.2 mg/kg). Both short-term stress and acute DEX administration, in parallel with Bcl-xL, caused a significant increase in tph2 mRNA levels and slightly enhanced tryptophan hydroxylase immunoreactivity in the midbrain. The increasing effect on the bcl-xl expression was specific to the short-term stress. Forced swim repeated daily for 2 weeks led to a decrease in bcl-xl mRNA in the midbrain without any effects on the Bcl-xL protein expression in the 5-HT neurons. In chronically stressed animals, an increase in tph2 gene expression was not associated with any changes in tryptophan hydroxylase protein levels. Our findings are the first to demonstrate that both short-term stress and acute glucocorticoid exposures induce Bcl-xL protein expression in the midbrain 5-HT neurons concomitantly with the activation of the 5-HT synthesis pathway in these neurons.     

Involvement of 5-HT1 and 5-HT5A Receptors in Modulation of Synaptic Transmission and Intrinsic Membrane Properties of Spinal Motoneurons of the Frog (Rana ridibunda)

Journal of Evolutionary Biochemistry and Physiology - The endogenous monoamine serotonin (5-HT) is involved in the modulation of motor output in vertebrates by interacting with different types of...     

Asymmetry in structure of in termediate and large neurons of frog retinal ganglion layer

We have carried out a morphometric investigation of the symmetry of intermediate (type II) and large (types III and V) ganglion cells on silver-impregnated retinal wholemounts of frog retina. We selected the nucleolus of theneuron and the axis passing through the nucleolus in the direction of the optic disk (central and bilateral symmetry) as elements of symmetry. We have shown that the dendritic ramification angles of all cell types are smaller than 360° and those of type II cells smaller than 180°; the cell somata do not lie in the center of the dendritic field and consequently the ganglion cells do not possess radial symmetry. In the vast majority of ganglion cells the directions of the start of the axon and dendrites are opposite to each other, the dendrites being oriented in the direction from the retinal center towards the periphery in all quadrants of the retinal map. For the estimation of the bilateral symmetry we measured the distance from the most remote dendritic terminals to the axis on the left and right of the axis, and counted the number of ramification knots and basal dendrites. We established that the majority of ganglion cells are asymmetrical as regards two or three of the characteristics mentioned. Consequently the asymmetrical structure of ganglion cells of the frog is a normal characteristic rather than an exception. The correlation between the asymmetry of the structure of ganglion cells and the functional asymmetry of their receptive fields is discussed.N. I. Lobachevskii Research Institute of Applied Mathematics and Cybernetics, University of Gorki. Translated from Neirofiziologiya, Vol. 17, No. 4, pp. 456–462, July–August, 1985.     

Complementary Transformations of Buried Organic Residues and the Ambient Sediment: Results of Long-Term Taphonomic Experiments

Long-term (18 month) experiments were conducted, burying soft bodied organisms (Artemia salina, Crustacea) in marine sediment. For the first time in experimental taphonomy, the mineralogical transformation of the sediment that accompanied the process of decomposition was correlated with the degree of preservation. To obtain different quantitative characteristics of preservation, we used four dilutions of marine water (marine water: to fresh water as 1: 0; 1: 1, 1: 4, 1: 9).It was shown that higher dilutions corresponded to lower degrees of preservation. The proportion of kaolinite decreased in the marine sediment and, accordingly, the amorphous phase increased; in the diluted variants, the opposite pattern was revealed: the crystalline kaolinite phase increased and the amorphous phase decreased. Since no differences in the chemical composition of the residues from different dilutions were identified, the effect of sea salt concentration on preservation was considered to be negligible. A plausible hypothesis suggested that dissolving of kaolinite slows of organic decomposition and the beginnings of mineralization. Due to the acidic hydrolysis of kaolinite, Al cations appear in the solution; subsequently proteins are converted into insoluble forms, and thus escape from bacterial degradation. These taphonomic experiments reveal some overlooked physicochemical aspects important for the mechanisms of exceptional preservation.     

Increment of hFIX expression with endogenous intron 1 in Vitro

This paper probes into the feasibility of increasing expression level of hFIX gene with endogenous intron 1 sequence.hFIX minigene was obtained with middle sequence truncated intron 1 inserted into the relative site of hFIX cDNA,and plasmid vector pKG5i‘IX,retroviral vector G1NaCi‘IX were constructed.These vectors were transduced into target cells of PA317,C2C12,primary rabbit skin fibroblasts (RSF) and primary human skin fibroblasts (HSF).The expression level of mixed colonies are PA317/pKG5i‘IX,151 ng/10^6 cells/24h;PA317/G1NaCi‘IX,308 ng/10^6 cells/24 h;C2C12/G1NaCi‘IX,186 ng/10^6 cells/24 h;RSF/G1NaCi‘IX,1929 ng/10^6 cells/24 h;HSF/G1NaCi‘IX,1646 ng/10^6 cells/24 h.These results indicated that hFIX minigene with intron l is able to increase the expression level to about 3 times of that of hFIX cDNA.Meanwhile,in order to study the application of hFIX minigene in the retroviral-mediated gene transfer system and refrain from intron splicing during viral production,a retroviral vector G1NaCi‘IXR with reversely inserted hFIX minigene expression cassette was constructed.The expression level of reverse constructor in PA317 cells was 390 ng/10^6 cells/24 h with 79% of bioactivity.PCR detection of HT/G1NaCi‘IXR cells infected with PA317/G1NaCi‘IXR supernatant confirmed the existence of intron 1 sequence.These results suggested that expression vector with forward-inserted intronl-carrying hFIX expression cassette can be used in directed gene transfer,but when using the retroviral-mediated gene transfer system,reversely-inserted intronl-carrying hFIX expression cassette should be considered.     

Structural properties of potexvirus coat proteins detected by optical methods

It has been shown by X-ray analysis that cores of coat proteins (CPs) from three potexviruses, flexible helical RNA-containing plant viruses, have similar α-helical structure. However, this similarity cannot explain structural lability of potexvirus virions, which is believed to determine their biological activity. Here, we used circular dichroism (CD) spectroscopy in the far UV region to compare optical properties of CPs from three potexviruses with the same morphology and similar structure. CPs from Alternanthera mosaic virus (AltMV), potato aucuba mosaic virus (PAMV), and potato virus X (PVX) have been studied in a free state and in virions. The CD spectrum of AltMV virions was similar to the previously obtained CD spectrum of papaya mosaic virus (PapMV) virions, but differed significantly from the CD spectrum of PAMV virions. The CD spectrum of PAMV virions resembled in its basic characteristics the CD spectrum of PVX virions characterized by molar ellipticity that is abnormally low for α-helical proteins. Homology modeling of the CP structures in AltMV, PAMV, and PVX virions was based on the known high-resolution structures of CPs from papaya mosaic virus and bamboo mosaic virus and confirmed that the structures of the CP cores in all three viruses were nearly identical. Comparison of amino acid sequences of different potexvirus CPs and prediction of unstructured regions in these proteins revealed a possible correlation between specific features in the virion CD spectra and the presence of disordered N-terminal segments in the CPs.