α-Synuclein modulation of Ca2+ signaling in human neuroblastoma (SH-SY5Y) cells

Parkinson's disease (PD) is characterized in part by the presence of α-synuclein (α-syn) rich intracellular inclusions (Lewy bodies). Mutations and multiplication of the α-synuclein gene ( SNCA ) are associated with familial PD. Since Ca²⁺ dyshomeostasis may play an important role in the pathogenesis of PD, we used fluorimetry in fura-2 loaded SH-SY5Y cells to monitor Ca²⁺ homeostasis in cells stably transfected with either wild-type α-syn, the A53T mutant form, the S129D phosphomimetic mutant or with empty vector (which served as control). Voltage-gated Ca²⁺ influx evoked by exposure of cells to 50 mM K⁺ was enhanced in cells expressing all three forms of α-syn, an effect which was due specifically to increased Ca²⁺ entry via L-type Ca²⁺ channels. Mobilization of Ca²⁺ by muscarine was not strikingly modified by any of the α-syn forms, but they all reduced capacitative Ca²⁺ entry following store depletion caused either by muscarine or thapsigargin. Emptying of stores with cyclopiazonic acid caused similar rises of [Ca²⁺]_i in all cells tested (with the exception of the S129D mutant), and mitochondrial Ca²⁺ content was unaffected by any form of α-synuclein. However, only WT α-syn transfected cells displayed significantly impaired viability. Our findings suggest that α-syn regulates Ca²⁺ entry pathways and, consequently, that abnormal α-syn levels may promote neuronal damage through dysregulation of Ca²⁺ homeostasis.     

石蝴蝶属一新种——黄斑石蝴蝶

描述了苦苣苔科（Gesneriaceae）石蝴蝶属(Petrocosmea Oliv.)一新种——黄斑石蝴蝶(P.xanthomaculata G.Q.Gou et X.Y.Wang)。新种与贵州石蝴蝶（P.cavaleriei Lévl.）相近,但叶多数,20～40枚,叶基心形,花冠白色,在裂片之间具明显黄色斑纹,苞片小,长约1 mm,花柱除上部外密被开展的白色长柔毛而不同。     

The impact of mating systems and dispersal on fine‐scale genetic structure at maternally,paternally and biparentally inherited markers

For decades, studies have focused on how dispersal and mating systems influence genetic structure across populations or social groups. However, we still lack a thorough understanding of how these processes and their interaction shape spatial genetic patterns over a finer scale (tens—hundreds of metres). Using uniparentally inherited markers may help answer these questions, yet their potential has not been fully explored. Here, we use individual‐level simulations to investigate the effects of dispersal and mating system on fine‐scale genetic structure at autosomal, mitochondrial and Y chromosome markers. Using genetic spatial autocorrelation analysis, we found that dispersal was the major driver of fine‐scale genetic structure across maternally, paternally and biparentally inherited markers. However, when dispersal was restricted (mean distance = 100 m), variation in mating behaviour created strong differences in the comparative level of structure detected at maternally and paternally inherited markers. Promiscuity reduced spatial genetic structure at Y chromosome loci (relative to monogamy), whereas structure increased under polygyny. In contrast, mitochondrial and autosomal markers were robust to differences in the specific mating system, although genetic structure increased across all markers when reproductive success was skewed towards fewer individuals. Comparing males and females at Y chromosome vs. mitochondrial markers, respectively, revealed that some mating systems can generate similar patterns to those expected under sex‐biased dispersal. This demonstrates the need for caution when inferring ecological and behavioural processes from genetic results. Comparing patterns between the sexes, across a range of marker types, may help us tease apart the processes shaping fine‐scale genetic structure.     

微生物分析方法测定保健食品中维生素B6的含量

称取保健强化食品样品,以0.22 mol/L H2SO4、121 ℃高压蒸汽锅水解、吸取合适浓度的检测样品到吡哆醇Y培养基中,接种卡尔斯伯(Saccharomyces Carlsberyensis)酵母菌,于(30±0.5) ℃恒温箱中培养18～22 h,用分光光度计在550 nm波长下测定酵母菌的生长,对应标准生长曲线求得样品中维生素B6(VB6)的含量,同时以同样的方法检测加标回收量.实验结果表明,该方法准确、回收率高、重复性好,便于实验室开展.     

二化螟盘绒茧蜂及稻虱缨小蜂对挥发物的嗅觉反应

【目的】揭示二化螟盘绒茧蜂Apanteles chilonis Munakata与稻虱缨小蜂Anagrus nilaparvatae对单一水稻挥发物组分的选择行为,了解水稻挥发物在其寄主搜寻过程中的作用,为水稻害虫寄生蜂引诱剂的研发提供技术基础。【方法】利用Y型嗅觉仪测定了二化螟盘绒茧蜂与稻虱缨小蜂对11种水稻挥发物组分(反-2-己烯醛、α-蒎烯、乙酸叶醇酯、芳樟醇、β-石竹烯、反-3-己烯醛、水杨酸甲酯、罗勒烯、苯甲醛、2-壬酮、柠檬烯)的嗅觉行为反应。【结果】β-石竹烯(10、50μg/kg)、罗勒烯(0.1、1、10μg/kg)、2-壬酮(10μg/kg)及反-2-己烯醛(50μg/kg)对二化螟盘绒茧蜂行为具有显著影响;稻虱缨小蜂对反-2-己烯醛(50μg/kg)、反-3-己烯醛(1、10、50μg/kg)、芳樟醇(0.1、1、10μg/kg)、β-石竹烯(0.1、50μg/kg)、罗勒烯(1μg/kg)、α-蒎烯(1μg/kg)和水杨酸甲酯(0.1、1、10、50μg/kg)有显著的嗅觉反应。【结论】寄生蜂对水稻挥发性气味的识别与挥发物的种类和浓度有很大关系,研发水稻害虫寄生蜂的引诱剂时需考虑挥发物的种类与浓度。     

Activation of the PDGF β Receptor by a Persistent Artificial Signal Peptide

Most eukaryotic transmembrane and secreted proteins contain N-terminal signal peptides that mediate insertion of the nascent translation products into the membrane of the endoplasmic reticulum. After membrane insertion, signal peptides typically are cleaved from the mature protein and degraded. Here, we tested whether a small hydrophobic protein selected for growth promoting activity in mammalian cells retained transforming activity while also acting as a signal peptide. We replaced the signal peptide of the PDGF β receptor (PDGFβR) with a previously described 29-residue artificial transmembrane protein named 9C3 that can activate the PDGFβR in trans. We showed that a modified version of 9C3 at the N-terminus of the PDGFβR can function as a signal peptide, as assessed by its ability to support high level expression, glycosylation, and cell surface localization of the PDGFβR. The 9C3 signal peptide retains its ability to interact with the transmembrane domain of the PDGFβR and cause receptor activation and cell proliferation. Cleavage of the 9C3 signal peptide from the mature receptor is not required for these activities. However, signal peptide cleavage does occur in some molecules, and the cleaved signal peptide can persist in cells and activate a co-expressed PDGFβR in trans. Our finding that a hydrophobic sequence can display signal peptide and transforming activity suggest that some naturally occurring signal peptides may also display additional biological activities by interacting with the transmembrane domains of target proteins.     

A Y‐chromosomal comparison of the Madjars (Kazakhstan) and the Magyars (Hungary)

The Madjars are a previously unstudied population from Kazakhstan who practice a form of local exogamy in which wives are brought in from neighboring tribes, but husbands are not, so the paternal lineages remain genetically isolated within the population. Their name bears a striking resemblance to the Magyars who have inhabited Hungary for over a millennium, but whose previous history is poorly understood. We have now carried out a genetic analysis of the population structure and relationships of the Madjars, and in particular have sought to test whether or not they show a genetic link with the Magyars. We concentrated on paternal lineages because of their isolation within the Madjars and sampled males representing all extant male lineages unrelated for more than eight generations (n = 45) in the Torgay area of Kazakhstan. The Madjars show evidence of extensive genetic drift, with 24/45 carrying the same 12‐STR haplotype within haplogroup G. Genetic distances based on haplogroup frequencies were used to compare the Madjars with 37 other populations and showed that they were closest to the Hungarian population rather than their geographical neighbors. Although this finding could result from chance, it is striking and suggests that there could have been genetic contact between the ancestors of the Madjars and Magyars, and thus that modern Hungarians may trace their ancestry to Central Asia, instead of the Eastern Uralic region as previously thought. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

版纳省藤的组织培养

以版纳省藤的萌蘖芽为试材,从取材、材料的处理、外植体的诱导分化、芽的增殖、生根以及影响试管苗形成几个重要因素等方面探讨了版纳省藤组织培养和快速繁殖的技术和方法,获得了生长素与细胞分裂素对芽的诱导分化及芽的增殖最佳配比浓度。以改良MS为基本培养基,在增殖培养基中添加0.5mg·L-1NAA、0.5mg·L-1KT和0.1mg·L-1BA,产生的有效苗最多;在生根培养基中添加1.5～2.0mg·L-1IBA生长素有利于版纳省藤组培苗生根。     

Y-chromosomal diversity in Haiti and Jamaica: contrasting levels of sex-biased gene flow

Although previous studies have characterized the genetic structure of populations from Haiti and Jamaica using classical and autosomal STR polymorphisms, the patrilineal influences that are present in these countries have yet to be explored. To address this lacuna, the current study aims to investigate, for the first time, the potential impact of different ancestral sources, unique colonial histories, and distinct family structures on the paternal profile of both groups. According to previous reports examining populations from the Americas, island-specific demographic histories can greatly impact population structure, including various patterns of sex-biased gene flow. Also, given the contrasting autosomal profiles provided in our earlier study (Simms et al.: Am J Phys Anthropol 142 (2010) 49-66), we hypothesize that the degree and directionality of gene flow from Europeans, Africans, Amerindians, and East Asians are dissimilar in the two countries. To test this premise, 177 high-resolution Y-chromosome binary markers and 17 Y-STR loci were typed in Haiti (n = 123) and Jamaica (n = 159) and subsequently utilized for phylogenetic comparisons to available reference collections encompassing Africa, Europe, Asia (East and South), and the New World. Our results reveal that both studied populations exhibit a predominantly South-Saharan paternal component, with haplogroups A1b-V152, A3-M32, B2-M182, E1a-M33, E1b1a-M2, E2b-M98, and R1b2-V88 comprising 77.2% and 66.7% of the Haitian and Jamaican paternal gene pools, respectively. Yet, European derived chromosomes (i.e., haplogroups G2a*-P15, I-M258, R1b1b-M269, and T-M184) were detected at commensurate levels in Haiti (20.3%) and Jamaica (18.9%), whereas Y-haplogroups indicative of Chinese [O-M175 (3.8%)] and Indian [H-M69 (0.6%) and L-M20 (0.6%)] ancestry were restricted to Jamaica.