H102对APP转基因小鼠脑内淀粉样蛋白和淀粉样蛋白前体蛋白表达的影响

目的:研究H102对APP695转基因模型小鼠脑内淀粉样蛋白和淀粉样蛋白前体蛋白表达的影响方法:9月龄转基因小鼠随机分为模型组和药物注射组,正常对照组采用月龄和性别与之相匹配的C57BL/6J小鼠。药物注射组给予侧脑室注射H102,每只每次3μl,连续10d;模型组和正常对照组给予等体积NS。应用免疫组织化学结合刚果红组织学染色,普通光学显微镜观察海马和颞叶皮层蛋白表达的变化。免疫印迹法检测小鼠大脑皮层APP蛋白的表达。结果:Aβ和APP免疫组化染色结果显示对照组海马CA1区神经元胞浆着色呈阴性或弱阳性,模型组较对照组阳性细胞增多,表达增强,胞浆着色明显加深。药物注射组同模型组相比,胞浆着色变淡,表达减弱。刚果红染色观察转基因小鼠模型组和H102注射组大脑颞叶皮层和海马的淀粉样斑块,可见H102注射组淀粉样斑块数较模型组明显减少。正常对照组未见阳性淀粉样斑块。免疫印迹检测显示模型组APP蛋白表达明显增加,给药组与模型组相比具有统计学意义。结论:APP695转基因小鼠大脑CA1区Aβ蛋白和APP蛋白表达增加,H102能够明显抑制该转基因小鼠Aβ蛋白和APP蛋白表达。     

A Simple Genetic Architecture Underlies Morphological Variation in Dogs

Domestic dogs exhibit tremendous phenotypic diversity, including a greater variation in body size than any other terrestrial mammal. Here, we generate a high density map of canine genetic variation by genotyping 915 dogs from 80 domestic dog breeds, 83 wild canids, and 10 outbred African shelter dogs across 60,968 single-nucleotide polymorphisms (SNPs). Coupling this genomic resource with external measurements from breed standards and individuals as well as skeletal measurements from museum specimens, we identify 51 regions of the dog genome associated with phenotypic variation among breeds in 57 traits. The complex traits include average breed body size and external body dimensions and cranial, dental, and long bone shape and size with and without allometric scaling. In contrast to the results from association mapping of quantitative traits in humans and domesticated plants, we find that across dog breeds, a small number of quantitative trait loci (≤3) explain the majority of phenotypic variation for most of the traits we studied. In addition, many genomic regions show signatures of recent selection, with most of the highly differentiated regions being associated with breed-defining traits such as body size, coat characteristics, and ear floppiness. Our results demonstrate the efficacy of mapping multiple traits in the domestic dog using a database of genotyped individuals and highlight the important role human-directed selection has played in altering the genetic architecture of key traits in this important species.     

Successful low dose insemination of flow cytometrically sorted Sika (Cervus nippon) sperm in Wapiti (Cervus elaphus)

The purpose of this study was to determine a practical method in Wapiti (Cervus elaphus) of using predetermined sexed Sika (Cervus nippon) semen. Semen was collected by electro-ejaculation from one stag of proven fertility and transported to the laboratory where it was retained as unsorted (control) or was separated into X- and Y-chromosome-bearing sperm using a modified high-speed cell sorter. Wapiti hinds (n = 81) were inseminated into the uterus by rectum manipulation with 1 × 10⁶ (X1 and Y1 group, respectively) or 2 × 10⁶ (X2 and Y2 group, respectively) of sorted frozen-thawed and 1 × 10⁷ non-sorted frozen-thawed (a commercial dose control) Sika motile sperm 60–66 h after removal of intra-vaginal progesterone-impregnated CIDR devices and administration of 700 IU of PMSG at the time of CIDR removal. The percentage of hinds calving after insemination was similar for X1 (38.5%), X2 (41.7%), Y1 (44.4%), Y2 (38.9%) groups (P > 0.05), but higher for control (75%) treatment (P < 0.05). Ultimately 15 out of the 16 Sika and Wapiti-hybrid calves produced by Wapiti hinds inseminated with Y-sorted sperm were male (93.7%) and 10/10 (100%) Sika and Wapiti-hybrid calves from hinds inseminated with X-sorted sperm were female. The sex ratio of the Sika and Wapiti-hybrid calves born to hinds inseminated with sex-sorted sperm deviated significantly (P < 0.05) from 50% and 50.0% in the control group. All Sika and Wapiti-hybrid calves were born between 237 and 250 d of gestation. Male and female calves in the control group had similar birth weights and weaning weights as calves from hinds inseminated with X- or Y-sorted sperm. In conclusion it can be said that normal Sika and Wapiti-hybrid calves of predicted sex can be produced after artificial insemination of Wapiti does with low numbers of sex-sorted cryopreserved Sika sperm.     

Synthesis and SAR of GlyT1 inhibitors derived from a series of N-((4-(morpholine-4-carbonyl)-1-(propylsulfonyl)piperidin-4-yl)methyl)benzamides

This Letter describes the synthesis and SAR, developed through an iterative analog library approach, of potent and selective non-sarcosine-derived GlyT1 inhibitors.     

Kinetics of the Competitive Degradation of Deoxyribose and Other Molecules by Hydroxyl Radicals Produced by the Fenton Reaction in the Presence of Ascorbic Acid

The competition method in which the Fenton reaction is employed as an OH radical generator and deoxyribose as a detecting molecule, has been used to determine the rate constants for reactions of the OH radical with its scavengers. Nonlinear competition plots were obtained for those scavengers which reacted with the Fenton reagents (Fe²⁺ or H₂O₂). Ascorbic acid is believed to overcome this problem. We have investigated the kinetics of deoxyribose degradation by -OH radicals generated by the Fenton reaction in the presence of ascorbic acid, and observed that the inclusion of ascorbic acid in the Fenton system greatly increased the rate of OH radical generation. As a result, the interaction between some scavengers and the Fenton reagents became negligeable and linear competition plots of A7A vs scavenger concentrations were obtained. The effects of experimental conditions such as, the concentrations of ascorbic acid, deoxyribose, H₂O₂ and Fe²⁺-EDTA, the EDTA/Fe²⁺ ratio as well as the incubation time, on the deoxyribose degradation and the determination of the rate constant for mercaptoethanol chosen as a reference compound were studied. The small standard error, (6.76± 0.21) ±' 10⁹M^-1s^-1 observed for the rate constant values for mercaptoethanol determined under 13 different experimental conditions, indicates the latter did not influence the rate constant determination. This is in fact assured by introducing a term, k_x, into the kinetic equation. This term represents the rate of-OH reactions with other reagents such as ascorbic acid, Fe²⁺-EDTA, H₂O₂ etc. The agreement of the rate constants obtained in this work with that determined by pulse radiolysis techniques for cysteine, thiourea and many other scavengers, suggests that this simple competition method is applicable to a wide range of compounds, including those which react with the Fenton reagents and those whose solubility in water is low.     

Effect of linker segments on the stability of epithelial cadherin Domain 2

Epithelial cadherin is a transmembrane protein that is essential in calcium-dependent cell-cell recognition and adhesion. It contains five independently folded globular domains in its extracellular region. Each domain has a seven-strand beta-sheet immunoglobulin fold. Short seven-residue peptide segments connect the globular domains and provide oxygens to chelate calcium ions at the interface between the domains (Nagar et al., Nature 1995;380:360-364). Recently, stability studies of ECAD2 (Prasad et al., Biochemistry 2004;43:8055-8066) were undertaken with the motivation that Domain 2 is a representative domain for this family of proteins. The definition of a domain boundary is somewhat arbitrary; hence, it was important to examine the effect of the adjoining linker regions that connect Domain 2 to the adjacent domains. Present studies employ temperature-denaturation and proteolytic susceptibility to provide insight into the impact of these linkers on Domain 2. The significant findings of our present study are threefold. First, the linker segments destabilize the core domain in the absence of calcium. Second, the destabilization due to addition of the linker segments can be partially reversed by the addition of calcium. Third, sodium chloride stabilizes all constructs. This result implies that electrostatic repulsion is a contributor to destabilization of the core domain by addition of the linkers. Thus, the context of Domain 2 within the whole molecule affects its thermodynamic characteristics.     

Synergistic Impact of Solvent and Polymer Additives on the Film Formation of Small Molecule Blend Films for Bulk Heterojunction Solar Cells

The addition of polystyrene (PS), a typical insulator, is empirically shown to increase the power conversion efficiencies (PCEs) of a solution‐deposited bulk heterojunction (BHJ) molecular blend film used in solar cell fabrication: p‐DTS(FBTTh₂)₂/PC₇₁BM. The performance is further improved by small quantities of diiodooctane (DIO), an established solvent additive. In this study, how the addition of PS and DIO affects the film formation of this bulk heterojunction blend film are probed via in situ monitoring of absorbance, thickness, and crystallinity. PS and DIO additives are shown to promote donor crystallite formation on different time scales and through different mechanisms. PS‐containing films retain chlorobenzene solvent, extending evaporation time and promoting phase separation earlier in the casting process. This extended time is insufficient to attain the morphology for optimal PCE results before the film sets. Here is where the presence of DIO comes into play: its low vapor pressure further extends the time scale of film evolution and allows for crystalline rearrangement of the donor phase long after casting, ultimately leading to the best BHJ organization.     

Vitamin A Deficiency Impairs Mucin Expression and Suppresses the Mucosal Immune Function of the Respiratory Tract in Chicks

The chicken immune system is immature at the time of hatching. The development of the respiratory immune system after hatching is vital to young chicks. The aim of this study was to investigate the effect of dietary vitamin A supplement levels on respiratory mucin and IgA production in chicks. In this study, 120 one-day-old broiler chicks were randomly divided into 4 groups consisting of three replicates of 10 broilers and subjected to dietary vitamin A supplement levels of 0, 1,500, 6,000, or 12,000 IU/kg for seven days. Compared with control birds, vitamin A supplementation significantly increased the mucin and IgA levels in the bronchoalveolar lavage fluid (BALF) as well as the IgA level in serum. In the lungs, vitamin A supplementation downregulated TNF-α and EGFR mRNA expression. The TGF-β and MUC5AC mRNA expression levels were upregulated by vitamin A supplementation at a dose of 6,000 IU/kg, and the IL-13 mRNA expression level was increased at the 12,000 IU/kg supplement level. Vitamin A deficiency (control) significantly decreased the mRNA expression levels of MUC2, IgA, EGFR, IL-13 and TGF-β in trachea tissue. Histological section analysis revealed that the number of goblet cells in the tracheal epithelium was less in the 0 and 12,000 IU/kg vitamin A supplement groups than in the other groups. In conclusion, vitamin A deficiency suppressed the immunity of the airway by decreasing the IgA and mucin concentrations in neonatal chicks. This study suggested that a suitable level of vitamin A is essential for the secretion of IgA and mucin in the respiratory tract by regulating the gene expression of cytokines and epithelial growth factors.     

Isolation and characterization of 12 microsatellite loci for Michelia coriacea (Magnoliaceae), a critically endangered endemic to Southeast Yunnan, China

By using a modified biotin–streptavidin capture method, a total of 12 microsatellite loci were developed and characterized for Michelia coriacea (Magnoliaceae), a critically endangered endemic to Southeast Yunnan, China. The number of alleles (A) ranged from two to six in 30 samples of this species. The ranges of observed (H _O ) and expected (H _E ) heterozygosities were 0.033–0.8000 and 0.033–0.7910, respectively. Cross-species amplification in M. yunnanensis showed that a subset of these markers holds promise for congeneric species. These polymorphic SSR markers would be useful tools for population genetics studies on M. coriacea and other congeneric species.     

Diversity and activity of methanotrophs in alkaline soil from a Chinese coal mine

Culture-independent molecular biological techniques, including 16S rRNA gene and functional gene clone libraries and microarray analyses using pmoA (encoding a key subunit of particulate methane monooxygenase), were applied to investigate the methanotroph community structure in alkaline soil from a Chinese coal mine. This environment contained a high diversity of methanotrophs, including the type II methanotrophs Methylosinus / Methylocystis , type I methanotrophs related to Methylobacter / Methylosoma and Methylococcus , and a number of as yet uncultivated methanotrophs. In order to identify the metabolically active methane-oxidizing bacteria from this alkaline environment, DNA stable isotope probing (DNA-SIP) experiments using ¹³CH₄ were carried out. This showed that both type I and type II methanotrophs were active, together with methanotrophs related to Methylocella , which had previously been found only in acidic environments. Methylotrophs, including Methylopila and Hyphomicrobium , were also detected in soil DNA and after DNA-SIP experiments. DNA sequence information on the most abundant, active methanotrophs in this alkaline soil will facilitate the design of oligonucleotide probes to monitor enrichment cultures when isolating key alkaliphilic methanotrophs from such environments.