Strong Genetic Differentiation of Primula sikkimensis in the East Himalaya–Hengduan Mountains

The East Himalaya-Hengduan Mountains region is the center of diversity of the genus Primula, and P. sikkimensis is one of the most common members of the genus in the region. In this study, the genetic diversity and structure of P. sikkimensis populations in China were assessed using inter-simple sequence repeat (ISSR) and chloroplast microsatellite markers. The 254 individuals analyzed represented 13 populations. High levels of genetic diversity were revealed by ISSR markers. At the species level, the expected heterozygosity and Shannon’s index were 0.4032 and 0.5576, respectively. AMOVA analysis showed that 50.3% of the total genetic diversity was partitioned among populations. Three pairs of chloroplast microsatellite primers tested yielded a total of 12 size variants and 15 chloroplast haplotypes. Strong cpDNA genetic differentiation (G _ST = 0.697) and evidence for phylogeographic structure were detected (N _ST = 0.788, significantly higher than G _ST). Estimated rates of pollen-mediated gene flow are approximately 27% greater than estimated rates of seed-mediated gene flow in P. sikkimensis. Both seed and pollen dispersal, however, are limited, and gene flow among populations appears to be hindered by the patchiness of the species’ habitats and their geographic isolation. These features may have played important roles in shaping the genetic structure of P. sikkimensis. A minimum-spanning tree of chloroplast DNA haplotypes was constructed, and possible glacial refugia of P. sikkimensis were identified.     

Drumstick is a zinc finger protein that antagonizes Lines to control patterning and morphogenesis of the Drosophila hindgut

Elongation of the Drosophila embryonic hindgut epithelium occurs by a process of oriented cell rearrangement requiring the genes drumstick (drm) and lines (lin). The elongating hindgut becomes subdivided into domains -- small intestine, large intestine and rectum -- each characterized by a specific pattern of gene expression dependent upon normal drm and lin function. We show that drm encodes an 81 amino acid (10 kDa) zinc finger protein that is a member of the Odd-skipped family. drm expression is localized to the developing midgut-hindgut junction and is required to establish the small intestine, while lin is broadly expressed throughout the gut primordium and represses small intestine fate. lin is epistatic to drm, suggesting a model in which localized expression of drm blocks lin activity, thereby allowing small intestine fate to be established. Further supporting this model, ectopic expression of Drm throughout the hindgut produces a lin phenotype. Biochemical and genetic data indicate that the first conserved zinc finger of Drm is essential for its function. We have thus defined a pathway in which a spatially localized zinc finger protein antagonizes a globally expressed protein, thereby leading to specification of a domain (the small intestine) necessary for oriented cell rearrangement.     

双七瓢虫对蚜虫捕食作用

【目的】研究双七瓢虫Coccinula quatuordecimpustulata(Linnaeus)对蚜虫的捕食习性,为其保护利用提供依据。【方法】采用13种蚜虫分别饲喂双七瓢虫1~4龄幼虫及成虫,观察记录24 h的捕食数量;选取大豆蚜Aphis glycines Matsumura、豌豆蚜Acyrthosiphon pisum(Harris)和白杨毛蚜Chaitophrus populeti(Panzer)分别对双七瓢虫进行饲养,记录瓢虫发育历期。【结果】双七瓢虫对供试的13种蚜虫捕食数量存在显著差异,其嗜食程度依照对蚜虫的日捕食生物量依次为:大豆蚜、菊小长管蚜Macrosiphoniella sanborni(Gillette)、月季长管蚜Sitobion rosivorum(Zhang)、豌豆蚜、甘蓝蚜Brevicoryne brassicae(Linnaeus)等;用大豆蚜和豌豆蚜饲养,双七瓢虫各虫态发育历期较短,用白杨毛蚜饲养则发育历期较长,3种蚜虫饲养的双七瓢虫,蛹均能正常羽化。【结论】双七瓢虫对供试蚜虫均有捕食行为,但捕食量存在明显差异;不同蚜虫对双七瓢虫的发育历期具有一定影响。     

Study of selective feeding in the marine cladoceran Penilia avirostris by HPLC pigment analysis

Food selection by the marine cladoceran Penilia avirostris was studied in the field by HPLC analysis of phytoplankton marker pigments and in the laboratory by microscopic measurement of cell removal. Comparison between pigment composition in natural phytoplankton and in P. avirostris showed that P. avirostris preferred diatoms, cryptophytes and chlorophytes, and ignored prymnesiophytes and dinoflagellates. Peridinin, the marker pigment for dinoflagellates was found in P. avirostris only when the dinoflagellate populations were dominated by Prorocentrum. Pigment degradation rates ranged from 13.73% for alloxanthin to 36.62% for chlorophyll a. Clearance rates measured in the laboratory provided further evidence of strong preference for diatoms and cryptophytes, and avoidance of dinoflagellates. Microscopic counts suggested that P. avirostris was feeding on prymnesiophytes, although ingestion of prymnesiophytes could not be confirmed by pigment analysis.     

Detection of local polarity of alpha-lactalbumin by N-terminal specific labeling with a new tailor-made fluorescent probe

To detect the local polarity such as the N-terminal domain of a protein molecule, 3-(4-chloro-6-hydrazino-1,3,5-triazinylamino)-7-(dimethylamino)-2-methylphenazine has been designed and synthesized as a polarity-sensitive fluorescent probe by using an s-triazine ring as a backbone, neutral red and hydrazine as a polarity-sensitive fluorophore, and a labeling group, respectively. The fluorescence properties of the probe have been characterized. The probe has the following features: (1) stable in various solvents; (2) the long-wavelength emission of >550 nm that can avoid the interferences of the background fluorescence shorter than 500 nm from common biomacromolecules; and (3) the maximum emission wavelength (lambda(em)) sensitive to solvent polarity only but not to pH and temperature. The hydrazino group in such a probe reacts readily with an active carbonyl produced by transamination of a protein molecule, leading to N-terminal specific attachment of the fluorophore and thereby allowing the monitoring of local polarity. With this probe, the polarity of the N-terminal domain in both native and heat-denatured alpha-lactalbumin has been first determined, which corresponds to that with a dielectric constant of about 16, and the hydrophobic core near the N-terminus is found to be conservative for heating. The present strategy may provide a general method to study the local environmental changes of a protein molecule under different denaturation conditions.     

Spinal Microglia and Astrocytes: Two Key Players in Chronic Visceral Pain Pathogenesis

Neurochemical Research - Chronic visceral pain (CVP) is one of the common symptoms of many diseases triggered by underlying diseases of the internal organs of the human body. Its causes include...     

注射和口服GnRH对小黄鱼人工催产效果的评估

为评估促性腺激素释放激素(Gonadotrophin releasing hormone, GnRH)作为外源激素对小黄鱼(Larimichthys polyactis)的人工催产繁殖效果, 以生理盐水注射组为对照, 设计促黄体素释放激素(LHRH-A2, 2.4 μg/kg)注射组、促性腺激素释放激素(GnRH, 75 μg/kg)注射组、促性腺激素释放激素(6 mg/kg)口服组, 通过繁殖生理学等方法比较其产卵情况、卵巢组织生理学变化和血清激素水平综合分析催产效果。结果显示, GnRH注射组在效应时间、产卵持续时间及受精率和孵化率与LHRH-A2注射组无显著差异, 但总产卵量和上浮卵重显著升高(P＜0.05); GnRH口服组总产卵量和上浮卵重则显著低于LHRH-A2注射组, 但受精率和孵化率无显著差异。进一步通过组织生理学分析小黄鱼产卵过程, 对照组卵巢发育以Ⅲ期卵巢为主, LHRH-A2注射组、GnRH注射和口服组均可诱导卵巢由Ⅲ期发育至Ⅴ期, 促进卵母细胞由Ⅲ和Ⅳ时相发育成熟并排出体外。各实验组经催产激素处理后, 血清中促黄体生成素(LH)、卵泡刺激素(FSH)和GnRH迅速上升, 至产卵后期仍维持较高水平, 各处理组的激素水平变化趋势一致。综上, 注射GnRH可有效诱导小黄鱼产卵, 且催产效果与注射LHRH-A2无显著差异; 口服GnRH也可以诱导小黄鱼产卵, 但产卵量和上浮卵重显著低于激素注射组, 对其给药方法和剂量需要进一步优化。