Population structure,diversity, and phylogeography in the near‐threatened Eurasian black vultures Aegypius monachus (Falconiformes; Accipitridae) in Europe: insights from microsatellite and mitochondrial DNA variation

The Eurasian black vulture (Aegypius monachus) has experienced a severe decline during the last two centuries and is globally classified as near‐threatened. This has led to the extinction of many traditional breeding areas in Europe and resulted in the present patchy distribution (Iberian and Balkan peninsulas) in the Western Palearctic. In the present study, we describe the current genetic status of the European populations using both mitochondrial cytochrome b sequences and nuclear microsatellite markers, comparing with those found in Asia (Mongolia and Caucasus region). Although, mitochondrial (mt)DNA revealed a relatively low genetic variability (haplotype diversity), no evidence of genome‐wide genetic erosion exists because nuclear diversity exhibits normal levels and strong differentiation. A highly philopatric dispersal behaviour must be invoked to explain the existence of a clear pattern that revealed by the phylogeographic analysis, which indicates a sharp East–West clinal distribution and an allopatric differentiation. The distribution of mtDNA haplotypes one in the Iberian population and two in Balkan population and the significance divergence at nuclear loci fulfill the definitions of those populations as evolutionary significant units. We discuss how management strategies should aim at the maintenance (or increase) of current genetic variability levels, suggesting that independent conservation plans are urgently required to protect these two breeding European populations from extinction. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 859–872.     

栀子水提取物对实验性2型糖尿病大鼠血糖及同型半胱氨酸水平的影响

观察栀子提取物对实验性2型糖尿病大鼠血糖、血脂及同型半胱氨酸水平的影响.采用Wistar雄性大鼠70只,随机抽取10只作为正常对照组,喂以普通维持饲料,其余60只高糖高脂饲料喂养4周后,ip链脲佐菌素(STZ)30 mg/kg建立2型糖尿病模型,7d后选取成模大鼠50只随机分为模型对照组(生理盐水)、盐酸二甲双胍对照组、栀子提取物低、中、高剂量组(0.2、0.4、0.6 g/kg),每组10只.连续ig给药4周后,观察各组大鼠血糖、血脂及同型半胱氨酸水平等变化.栀子提取物ig能降低糖尿病大鼠的血糖、甘油三酯(TG)、胆固醇(TC)、低密度脂蛋白(LDLC),同时能升高高密度脂蛋白(HDLC),降低同型半胱氨酸水平.     

枯草芽孢杆菌C-D6对辣椒炭疽菌附着胞形成的抑制作用研究

【目的】研究枯草芽孢杆菌(Bacillus subtilis) C-D6菌株对辣椒炭疽菌(Colletotrichum capsici)附着胞形成的抑制作用,探索炭疽病生物防治的新途径。【方法】通过对峙培养测定C-D6菌株的抗菌活性,应用摇瓶培养结合生物测定筛选产生抗菌活性成分的最适培养基,采用硫酸铵分级沉淀、Sephadex G-75凝胶柱层析和阴离子交换层析对抗菌蛋白进行分离纯化,应用聚丙烯酰胺凝胶电泳测定蛋白分子量。【结果】C-D6菌株在PDA平板上对辣椒炭疽菌显示明显的抑制作用,其YPD培养液能完全抑制该菌的附着胞形成。摇瓶培养的结果显示C-D6菌株产生抗菌活性物质的最适培养基为YPD培养基。C-D6菌株在该培养基中培养14 h后,所形成的活性物质可完全抑制辣椒炭疽菌的附着胞形成。从该菌的YPD培养液中分离获得一个分子量为32 kD,能明显抑制辣椒炭疽菌附着胞形成的抗菌蛋白。【结论】C-D6菌株的生防特征显示该菌株对防治辣椒炭疽菌引起的炭疽病具有潜在的应用价值。     

Long- and short-term effects of decreased sink demand on carbohydrate levels and photosynthesis in wheat leaves

Wheat (Triticum aestivum L.) ears were removed to investigate long-term regulation of photosynthesis by sink demand at ambient CO₂ and 22 °C. The CO₂ level was also increased to 660 μmol mol^?1 and temperature was lowered to 5 °C to examine short-term responses of photosynthesis to low sink demand. Sink removal inhibited photosynthesis and increased leaf levels of glucose, fructose and ribulose-1, 5-bisphosphate (RuBP), and the glucose-6-phosphate (G6P)/fructose-6-phosphate (F6P) and RuBP/3-phosphoglycerate (PGA) ratios under growth conditions, but had no effect on the activity and activation state of ribulose-1, 5-bisphosphate carboxylase oxygenase (Rubisco) either under growth or short-term conditions, suggesting an inhibition of photosynthesis by decreased in vivo catalysis of Rubisco. Photosynthesis increased similarly in eared and earless shoots after a rise in CO₂ concentration, and the ratio of triose-phosphates (glyceraldehyde 3-phosphate and dihydroxyacetone phosphate, TP) to PGA was similar or higher for removed than intact ears, suggesting that feedback inhibition of photosynthesis was not caused by a limitation of ATP synthesis in chloroplasts. Under short-term conditions (660 μmol mol^?1 CO₂, 5 °C), TP and RuBP levels and the TP/PGA and TP/RuBP ratios were increased by sink removal, indicating an additional limitation of photosynthesis by the rate of RuBP regeneration.     

Functional analysis of the Alternaria brassicicola non-ribosomal peptide synthetase gene AbNPS2 reveals a role in conidial cell wall construction

Alternaria brassicicola is a necrotrophic pathogen causing black spot disease on virtually all cultivated Brassica crops worldwide. In many plant pathosystems fungal secondary metabolites derived from non-ribosomal peptide synthetases (NPSs) are phytotoxic virulence factors or are antibiotics thought to be important for niche competition with other micro-organisms. However, many of the functions of NPS genes and their products are largely unknown. In this study, we investigated the function of one of the A. brassicicola NPS genes, AbNPS2 . The predicted amino acid sequence of AbNPS2 showed high sequence similarity with A. brassicae , AbrePsy1, Cochliobolus heterostrophus , NPS4 and a Stagonospora nodorum NPS. The AbNPS2 open reading frame was predicted to be 22 kb in length and encodes a large protein (7195 amino acids) showing typical NPS modular organization. Gene expression analysis of AbNPS2 in wild-type fungus indicated that it is expressed almost exclusively in conidia and conidiophores, broadly in the reproductive developmental phase. AbNPS2 gene disruption mutants showed abnormal spore cell wall morphology and a decreased hydrophobicity phenotype. Conidia of abnps2 mutants displayed an aberrantly inflated cell wall and an increase in lipid bodies compared with wild-type. Further phenotypic analyses of abnps2 mutants showed decreased spore germination rates both in vitro and in vivo , and a marked reduction in sporulation in vivo compared with wild-type fungus. Moreover, virulence tests on Brassicas with abnps2 mutants revealed a significant reduction in lesion size compared with wild-type but only when aged spores were used in experiments. Collectively, these results indicate that AbNPS2 plays an important role in development and virulence.     

根据外部形态特征试论披碱草属3组植物间的系统关系

通过对披碱草属中小颖组、宽颖组和长颖组种类外部形态的观察,总结了3组植物外部形态特征的异同,探讨了形态学特征的分类学意义。同时,根据3组植物外部形态性状—花序、小穗、小花、以及内稃的演化趋势,分析了各组的演化关系和系统位置。结果表明：小颖组最原始,宽颖组较进化,长颖组最高级;小颖组可能直接派生了较进化的宽颖组,并在宽颖组的基础上进而产生了最高级的长颖组。此外,本文对披碱草属参试种的系统关系也作了一定程度的探讨,结果显示圆锥披碱草最原始,墨西哥披碱草最进化,其余参试种居于两者之间。上述研究工作为整个披碱草属系统与进化方面的探讨提供了形态学方面的理论证据。     

Spectral properties of a long-wavelength absorbing form of protochlorophyll in seeds of Cyclanthera explodens

The in vivo absorbance spectrum of the inner seed coat of Cyclanthera explodens Naud. showed a main peak in the red region at 671 nm and a weak shoulder at about 640 nm. The pigments were extracted with acetone. separated by paper chromatography and analysed spectrophotometrically. The only detectable pigment was protochlorophyll. The in vivo fluorsecence emission spectra had two main peaks, one at 632 and one at 691 nm. The relation between the two peaks was changed when the exvcitation wavelength was altered from 440 to 460 nm. Excitation at 420 nm gave an additional fluorescence emission peak at 595 nm. These data indicate the presence of at least three forms of protochlorophyll in the Cyclantera seed coat. The spectrum of circular dichroism had a very intence and characteristic signal in the red region with a negative asymmetrical Cotton effect (664 (+), 669 (0) and 687 (?) nm). This indicates that at least one of the protochlorophyll forms is present in a more or less crystalline form.