SNARE Proteins Synaptobrevin,SNAP-25, and Syntaxin Are Involved in Rapid and Slow Endocytosis at Synapses

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Sphingolipids with neuritogenic activity from Euphorbia sororia

Two groups of sphingolipids 1 and 2 were isolated from the aerial parts of Euphorbia sororia. On the basis of spectroscopic data, chemical methods and GC-MS analysis, the structures of 1 and 2 were characterized as 1-O-beta-D-glucopyranosyl-(2S,3S,4R,8Z)-2-[(2'R)-2'-hydroxydocosanoyl approximately hexacosanoyl, octacosanoyl amino]-1,3,4-octadecanetriol-8-ene and (2S,3S,4R,8E)-2-[(2'R)-2'-hydroxyeicosanoyl approximately hexacosanoyl amino]-1,3,4-octadecanetriol-8-ene, respectively. Both of them exhibited marked neuritogenic activity on the rat pheochromocytoma PC12 cell line.     

A light and electron microscopic study of glutamate receptors in the monkey subthalamic nucleus

The distribution of glutamate receptors in the monkey subthalamic nucleus was studied using affinity purified polyclonal antibodies to GluR1, phosphorylated GluR1, GluR2/3, NMDAR1, mGluR1a and mGluR5. Intense staining for both the unphosphorylated and the phosphorylated forms of the AMPA receptor subunit GluR1 was observed in the cell bodies and proximal dendrites of neurons in this nucleus. In comparison to GluR1, less intense staining for GluR2/3 was observed in the cell bodies and processes. NMDAR1 immunoreactivity was present in cell bodies and large numbers of small diameter dendrites. Light staining was observed in cell bodies with mGluR1a and no staining was observed on cell bodies with mGluR5. The neuropil, however, contained many processes that were labeled for mGluR1a or mGluR5. Electron microscopy showed that label was present in cytoplasmic locations in cell bodies and dendrites, in addition to components of the synaptic region, in sections stained for GluR1, GluR2/3 and NMDAR1. In contrast, very lightly labeled or unlabeled cell bodies but labeled dendrites and axon terminals, was observed in sections stained for mGluR1a and mGluR5. In addition to neural processes, occasional astrocytic processes were also labeled for mGluR5. Of the immunogold particles that were associated with components of the synaptic region, label for ionotropic glutamate receptors was mostly present on postsynaptic densities, whilst that for metabotropic glutamate receptors was mostly present in a perisynaptic location. The ratio of GluR1/GluR2 messenger RNAs has been reported to increase in the aged hippocampus (PAGLIUSI, S. R., GERRARD, P., ABDALLAH, M., TALABOT, D. & CATSICAS, S. (1994) Neuroscience 61, 429–433.), and it is possible that a similar change in the ratio of GluR1 and GluR2 may occur in neurons of the subthalamic nucleus with age. It is postulated that this could result an increase in calcium permeability via AMPA receptors, and an enhancement of excitatory transmission in this nucleus.     

A general framework for marker-assisted selection

Early simulation studies have showed that the inclusion of epistatic components (especially the additive-by-additive effects) into marker-assisted selection (MAS) can improve selection efficiency for a short-term breeding program. In this study I extend Lande and Thompson's theory to incorporate both additive and non-additive effects into MAS with reference to the mass selection case. Four different indices are analytically examined in terms of the type of genetic components involved in the marker scores: phenotype-, general combining ability (GCA)-, and GCA and reciprocal effects-based marker scores. The phenotype-based marker index is applicable to any population of non-random mating, while the other three indices are applicable to the synthetic population derived from diallel crosses. All these indices may have higher selection efficiencies than the index with solely additive effects-associated markers as long as the detectable transient non-additive effects are present. The improvement in selection efficiency depends on the magnitude of non-additive variances and the proportion of them explained by markers. The index with the phenotype-based marker scores operates on the whole of the additive and non-additive effects, and has the largest selection efficiency. The indices with the GCA-based marker scores operate only on additive and additive-by-additive genetic variation and have relatively small selection efficiencies. Inclusion of the markers from organelle genomes can also increase selection efficiency, depending upon the proportion of the total genetic variation attributable to organelle genomes and the proportion of them explained by organelle genomic markers. Sharing of markers among different marker scores does not facilitate the improvement of selection efficiency.     

Description of male Takydromus sylvaticus (Squamata: Lacertidae) from China, with notes on sexual dimorphism and a revision of the morphological diagnosis of the species

The Chungan ground lizard, Takydromus sylvaticus, long known only from five females collected in Fujian Province of China, was recently found in Anhui Province of the country. The newly collected specimens included the first male specimens (n=7), in which the tail bases were stouter than in conspecific females. Ventral scales in these males were invariably keeled, whereas in females those forming the four median rows were smooth. Females had more dorsal scales (47-48) than males (42-43) in the median longitudinal row between axilla and groin. Takydromus sylvaticus differed from the closely related T. dorsalis in having more dorsal scales in the median longitudinal row between axilla and groin (42-48 versus 32-40, respectively), more rows of large dorsal scales between the hind legs (10 versus 7-8, respectively), shorter hind legs, two distinct white longitudinal stripes on each side of the body, and no black stripe in the preocular and postocular regions. The number of transverse rows of ventral scales between collar and femoral pores in T. sylvaticus (26-28) was larger, but with a slight overlap, than that in T. dorsalis (22-26). Ecological observations on T. sylvaticus were also documented.     

Amperometric glucose biosensor based on self-assembly hydrophobin with high efficiency of enzyme utilization

Hydrophobins are a family of natural self-assembling proteins with high biocompability, which are apt to form strong and ordered assembly onto many kinds of surfaces. These physical-chemical and biological properties make hydrophobins suitable for surface modification and biomolecule immobilization purposes. A class II hydrophobin HFBI was used as enzyme immobilization matrix on platinum electrode to construct amperometric glucose biosensor. Permeability of HFBI self-assembling film was optimized by selecting the proper HFBI concentration for electrode modification, in order to allow H₂O₂ permeating while prevent interfering compounds accessing. HFBI self-assembly and glucose oxidase (GOx) immobilization was monitored by quartz crystal microbalance (QCM), and characterization of the modified electrode surface was obtained by scanning electron microscope (SEM). The resulting glucose biosensors showed rapid response time within 6 s, limits of detection of 0.09 mM glucose (signal-to-noise ratio = 3), wide linear range from 0.5 to 20 mM, high sensitivity of 4.214 × 10⁻³ A M⁻¹ cm⁻², also well selectivity, reproducibility and lifetime. The all-protein modified biosensor exhibited especially high efficiency of enzyme utilization, producing at most 712 μA responsive current for per unit activity of GOx. This work provided a promising new immobilization matrix with high biocompatibility and adequate electroactivity for further research in biosensing and other surface functionalizing.     

Secondary structure and 3D homology modeling of grass carp (Ctenopharyngodon idellus) major histocompatibility complex class I molecules

No information to date is available on the structure of fish major histocompatibility complex (MHC) class I and beta2-microglobulin (beta2m) proteins. In the present study, grass carp (Ctenopharyngodon idellus) MHC class I (Ctid-MHC I) and beta(2)-microglobulin (Ctid-beta2m) genes were expressed as soluble maltose binding protein (MBP)-proteins and purified in a pMAL-p2X/Escherichia coli TB1 system. The expressed proteins were purified on amylase affinity columns followed by DEAE-Sepharose. The purified products were identified by Western blotting with anti-MBP polyclonal antibodies. The MBP-Ctid-MHC I and MBP-Ctid-beta2m were cleaved separately with Factor Xa, mixed together and purified on DEAE-Sepharose. The secondary structures were analyzed by circular dichroism (CD) spectrophotometry. The three-dimensional (3D) structure of their peptide-binding domain (PBD) was modeled based sequence homology. The sequence lengths of the alpha-helix, beta-sheet, turn, and random coil in the Ctid-MHC I protein were 79aa, 75aa, 20aa, and 99aa, respectively. In the 97aa of Ctid-beta2m, the contents of the alpha-helix, beta-sheet, turn, and random coil were 0aa, 41aa, 12aa, and 44aa, respectively. The Ctid-beta2m protein displayed a typical beta-sheet. Homology modeling of the Ctid-MHC I and Ctid-beta2m proteins demonstrated similarities with the structure of human MHC class I proteins.     

Genetic model of selective COX2 inhibition reveals novel heterodimer signaling

Selective inhibitors of cyclooxygenase-2 (COX2) have attracted widespread media attention because of evidence of an elevated risk of cardiovascular complications in placebo-controlled trials, resulting in the market withdrawal of some members of this class. These drugs block the cyclooxygenase activity of prostaglandin H synthase-2 (PGHS2), but do not affect the associated peroxidase function. They were developed with the rationale of conserving the anti-inflammatory and analgesic actions of traditional nonsteroidal anti-inflammatory drugs (tNSAIDs) while sparing the ability of PGHS1-derived prostaglandins to afford gastric cytoprotection. PGHS1 and PGHS2 coexist in the vasculature and in macrophages, and are upregulated together in inflammatory tissues such as rheumatoid synovia and atherosclerotic plaque. They are each believed to function as homodimers. Here, we developed a new genetic mouse model of selective COX2 inhibition using a gene-targeted point mutation, resulting in a Y385F substitution. Structural modeling and biochemical assays showed the ability of PGHS1 and PGHS2 to heterodimerize and form prostaglandins. The heterodimerization of PGHS1-PGHS2 may explain how the ductus arteriosus closes normally at birth in mice expressing PGHS2 Y385F, but not in PGHS2-null mice.     

Hubbell's fundamental biodiversity parameter and the Simpson diversity index

Central to Hubbell's neutral theory of biodiversity is a universal, dimensionless fundamental biodiversity parameter that is the product of community size and speciation rate. One of the most important discoveries of Hubbell's theory is that the species‐abundance distribution and the species–area relationship of the neutral metacommunity is completely determined by this fundamental biodiversity parameter, although the diversity patterns of the local community are collectively determined by the biodiversity parameter and migration. Using the relative abundance of species and following the concept of heterozygosity of population genetics, here we developed an analytical relationship between this biodiversity parameter and the well‐known Simpson diversity index. This relationship helps bridge the evolutionary aspect of biodiversity to the ecological and statistical aspect of the diversity. The relationship between these two parameters suggests that diversity patterns of the metacommunity can also be equally described by the Simpson index. This relationship provides an alternative approach to interpret and estimate the fundamental biodiversity parameter for the metacommunity.     

一例12号染色体臂间倒位的细胞遗传学研究

小麦主要经济性状大多属数量性状,是受 微效多基因控制的。为了探索小麦常用亲本配 制组合时各主要经济性状的遗传变异规律,于 1980年选用了江苏、浙江两省普遍采用的UP 301、泰山1号、908、早白、白壳早、短秆早6 个品种作为杂交亲本,研究并分析了主要经济 性状的遗传参数,为有效地选配亲本,提高育种 成效,提供一些理论依据。