β-蝮蛇毒素对蟾蜍交感神经节突触传递的影响

β-蝮蛇毒素(β-agkistrodotoxin简写β-AgTX)对骨胳肌神经肌肉接头的作用已有实验分析,本文则观察了β-AgTX对蟾蜍交感神经节胆碱能性和非胆碱能性突触电位的作用。结果表明,β-AgTX对胆碱能性快兴奋性突触后电位(f-EPSP)和由压力微量注射ACh产生的ACh电位快成分有可逆性抑制作用,且对f-EPSP的幅值抑制率明显大于对ACh电位的抑制率,方差分析显示β-AgTX对f-EPSP和对ACh电位的抑制之间的差异显著(P<0.01)。β-AgTX对非胆碱能性迟慢兴奋性突触后电位(1s-EPSP)无明显作用。本结果提示β-AgTX可能是通过抑制节前神经末梢释放AGh的突触前机制和占据突触后N型胆碱能受体影响ACh的作用之突触后机制,抑制蟾蜍交感神经节的胆碱能性传递过程。     

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

Sleep and Biological Rhythms - The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously...     

KIR Gene Content in Amerindians Indicates Influence of Demographic Factors

Although the KIR gene content polymorphism has been studied worldwide, only a few isolated or Amerindian populations have been analyzed. This extremely diverse gene family codifies receptors that are expressed mainly in NK cells and bind HLA class I molecules. KIR-HLA combinations have been associated to several diseases and population studies are important to comprehend their evolution and their role in immunity. Here we analyzed, by PCR-SSP (specific sequencing priming), 327 individuals from four isolated groups of two of the most important Brazilian Amerindian populations: Kaingang and Guarani. The pattern of KIR diversity among these and other ten Amerindian populations disclosed a wide range of variation for both KIR haplotypes and gene frequencies, indicating that demographic factors, such as bottleneck and founder effects, were the most important evolutionary factors in shaping the KIR polymorphism in these populations.     

大菜粉蝶颗粒体病毒的研究:包含体结合的碱性蛋白酶

本文报道从新疆分离的一株大菜粉蝶(Pieris brassicae)颗粒体病毒(PbGV)包含体上结合有碱性蛋白酶.提取含酶的包含体蛋白,以酪蛋白为底物鉴定表明此酶在pH9.4有最大的酶活力,并定位于“包裹”在病毒粒子套膜外的包含体蛋白中.在高pH时分子皿为26,500的包含体蛋白被酶降解为19,500和15,600道尔顿的两个组分.Hg⁺⁺、Cu⁺⁺仅部分抑制酶活力,可被二异丙基氟磷酸(DFP)完全抑制.75℃以上加热处理可使酶失活,并大大降低病毒包含体的解离.推测此酶是影响PbGV对寄主感染率的因子之一.     

Regulation of tyrosinase processing and trafficking by organellar pH and by proteasome activity

Pigmentation of the hair, skin, and eyes of mammals results from a number of melanocyte-specific proteins that are required for the biosynthesis of melanin. Those proteins comprise the structural and enzymatic components of melanosomes, the membrane-bound organelles in which melanin is synthesized and deposited. Tyrosinase (TYR) is absolutely required for melanogenesis, but other melanosomal proteins, such as TYRP1, DCT, and gp100, also play important roles in regulating mammalian pigmentation. However, pigmentation does not always correlate with the expression of TYR mRNA/protein, and thus its function is also regulated at the post-translational level. Thus, TYR does not necessarily exist in a catalytically active state, and its post-translational activation could be an important control point for regulating melanin synthesis. In this study, we used a multidisciplinary approach to examine the processing and sorting of TYR through the endoplasmic reticulum (ER), Golgi apparatus, coated vesicles, endosomes and early melanosomes because those organelles hold the key to understanding the trafficking of TYR to melanosomes and thus the regulation of melanogenesis. In pigmented cells, TYR is trafficked through those organelles rapidly, but in amelanotic cells, TYR is retained within the ER and is eventually degraded by proteasomes. We now show that TYR can be released from the ER in the presence of protonophore or proton pump inhibitors which increase the pH of intracellular organelles, after which TYR is transported correctly to the Golgi, and then to melanosomes via the endosomal sorting system. The expression of TYRP1, which facilitates TYR processing in the ER, is down-regulated in the amelanotic cells; this is analogous to a hypopigmentary disease known as oculocutaneous albinism type 3 and further impairs melanin production. The sum of these results shows that organellar pH, proteasome activity, and down-regulation of TYRP1 expression all contribute to the lack of pigmentation in TYR-positive amelanotic melanoma cells.     

Y-chromosome evidence for differing ancient demographic histories in the Americas

To scrutinize the male ancestry of extant Native American populations, we examined eight biallelic and six microsatellite polymorphisms from the nonrecombining portion of the Y chromosome, in 438 individuals from 24 Native American populations (1 Na Dené and 23 South Amerinds) and in 404 Mongolians. One of the biallelic markers typed is a recently identified mutation (M242) characterizing a novel founder Native American haplogroup. The distribution, relatedness, and diversity of Y lineages in Native Americans indicate a differentiated male ancestry for populations from North and South America, strongly supporting a diverse demographic history for populations from these areas. These data are consistent with the occurrence of two major male migrations from southern/central Siberia to the Americas (with the second migration being restricted to North America) and a shared ancestry in central Asia for some of the initial migrants to Europe and the Americas. The microsatellite diversity and distribution of a Y lineage specific to South America (Q-M19) indicates that certain Amerind populations have been isolated since the initial colonization of the region, suggesting an early onset for tribalization of Native Americans. Age estimates based on Y-chromosome microsatellite diversity place the initial settlement of the American continent at approximately 14,000 years ago, in relative agreement with the age of well-established archaeological evidence.     

Development and standardization of multiplexed antibody microarrays for use in quantitative proteomics

BACKGROUND: Quantitative proteomics is an emerging field that encompasses multiplexed measurement of many known proteins in groups of experimental samples in order to identify differences between groups. Antibody arrays are a novel technology that is increasingly being used for quantitative proteomics studies due to highly multiplexed content, scalability, matrix flexibility and economy of sample consumption. Key applications of antibody arrays in quantitative proteomics studies are identification of novel diagnostic assays, biomarker discovery in trials of new drugs, and validation of qualitative proteomics discoveries. These applications require performance benchmarking, standardization and specification. RESULTS: Six dual-antibody, sandwich immunoassay arrays that measure 170 serum or plasma proteins were developed and experimental procedures refined in more than thirty quantitative proteomics studies. This report provides detailed information and specification for manufacture, qualification, assay automation, performance, assay validation and data processing for antibody arrays in large scale quantitative proteomics studies. CONCLUSION: The present report describes development of first generation standards for antibody arrays in quantitative proteomics. Specifically, it describes the requirements of a comprehensive validation program to identify and minimize antibody cross reaction under highly multiplexed conditions; provides the rationale for the application of standardized statistical approaches to manage the data output of highly replicated assays; defines design requirements for controls to normalize sample replicate measurements; emphasizes the importance of stringent quality control testing of reagents and antibody microarrays; recommends the use of real-time monitors to evaluate sensitivity, dynamic range and platform precision; and presents survey procedures to reveal the significance of biomarker findings.     

Induction of apoptosis by Centaurea nerimaniae extract in HeLa and MDA-MB-231 cells by a caspase-3 pathway

We investigated the cytotoxic and apoptotic effects of a methanol extract of Centaurea nerimaniae, a plant endemic in Turkey, on HeLa and MDA-MB-231 cells. Eight concentrations of C. nerimaniae extract were applied to cells, and cytotoxic effects were measured using the xCELLigence system. The TUNEL assay was used to assess apoptotic cell death and immunohistochemistry was used to determine active caspase-3 using the effective cytotoxic doses of the extract. Doses of 1.42 mg/ml C. nerimaniae inhibited the growth of HeLa cells and 3.67 mg/ml C. nerimaniae inhibited the growth of MDA-MB-231 cells in a dose- and time-dependent manner. The apoptotic indexes for HeLa and MDA-MB-231 cells were increased significantly compared to control groups. Immunohistochemistry showed that the number of caspase-3 immunostained cells increased in the extract treatment groups for both HeLa and MDA-MB-231 cells. In the MDA-MB-231 cell line, caspase-3 immunostaining was observed in nuclei and/or cytoplasm in the extract treated group. Caspase-3 activation was greater in HeLa cells than in MDA-MB-231 cells. We found that the extract of C. nerimaniae had a strong antiproliferative effect and induced apoptosis via caspase-3; MDA-MB-231 cancer cells were more resistant than HeLa cells.     

Features of wild-type human SOD1 limit interactions with misfolded aggregates of mouse G86R Sod1

Mutations in the gene encoding superoxide dismutase 1 (SOD1) account for about 20% of the cases of familial amyotrophic lateral sclerosis (fALS). It is well established that mutations in SOD1, associated with fALS, heighten the propensity of the protein to misfold and aggregate. Although aggregation appears to be a factor in the toxicity of mutant SOD1s, the precise nature of this toxicity has not been elucidated. A number of other studies have now firmly established that raising the levels of wild-type (WT) human SOD1 (hSOD1) proteins can in some manner augment the toxicity of mutant hSOD1 proteins. However, a recent study demonstrated that raising the levels of WT-hSOD1 did not affect disease in mice that harbor a mouse Sod1 gene (mSod1) encoding a well characterized fALS mutation (G86R). In the present study, we sought a potential explanation for the differing effects with WT-hSOD1 on the toxicity of mutant hSOD1 versus mutant mSod1. In the cell culture models used here, we observe poor interactions between WT-hSOD1 and misfolded G86R-mSod1, possibly explaining why over-expression of WT-hSOD1 does not synergize with mutant mSod1 to accelerate the course of the disease in mice.