Microsatellite diversity of the agriculturally important alpine grass Poa alpina in relation to land use and natural environment

BACKGROUND AND AIMS: The Alpine Meadow Grass Poa alpina is common in subalpine and alpine natural sites and agriculturally used land, where it is an important fodder grass. Natural factors and human land use are supposed to have been shaping its genetic diversity for hundreds of years. The species comprises sexually and vegetatively reproducing plants. The aim of this study was to investigate the effects of agricultural land use, environmental factors and the mode of reproduction on the distribution of its microsatellite diversity within and among populations and to analyse whether its genetic diversity is correlated with plant species diversity in grassland parcels. METHODS: Genetic diversity of P. alpina was assessed with five microsatellite markers for 569 plants originating from 20 natural sites and from 54 grassland parcels of different cultural tradition, land use and altitude in the Swiss Alps. Due to polyploidy and frequent aneuploidy of the species, data analyses were based on the presence of microsatellite bands. KEY RESULTS: A low but significant differentiation was found in microsatellite bands among natural sites and agriculturally used parcels, while their microsatellite band diversity within populations did not differ. An increased differentiation was found in microsatellite bands with increasing geographic distance among parcels, and a differentiation among grazed and mown parcels, and among sexually and vegetatively reproducing populations. Band richness of sampled plants per village was higher for villages where parcels represented more different land-use types. Within populations, microsatellite band diversity was higher in grazed than in mown parcels. CONCLUSIONS: The diversity of human land use in the Alps was associated with genetic diversity of P. alpina. Therefore, the ongoing socio-economically motivated land-use changes, which reduce the number of different land-use types, will affect the genetic diversity of P. alpina negatively.     

Antioxidant and Antimelanogenic Activities of Compounds Isolated from the Aerial Parts of Achillea alpina L.

Achillea alpina is widely distributed in Korea and is often used as a folk medicine for stomach disorders. Although a previous study isolated antioxidant compounds (flavonoid O‐glucoside, sesquiterpene) from this plant, no systematic study of its chemical constituents had been reported. The present study aimed to identify the phytochemicals present in a methanol extract of A. alpina, assess their potential antioxidant activities in vitro, and determine their effects on melanogenesis in B16F10 melanoma cells. Column chromatographic separation of aqueous fractions of A. alpina led to the isolation of 17 compounds. The chemical structures of these compounds were determined using spectroscopic data from electrospray ionization‐mass spectrometry and nuclear magnetic resonance. To the best of our knowledge, the present study is the first to identify compounds 2 – 10 and 12 – 17 in A. alpina. Furthermore, compound 6 possessed powerful antioxidant activity, while compound 15 suppressed intracellular tyrosinase activity and thus reduced melanogenesis in B16F10 cells. Therefore, our research suggested that these naturally occurring compounds have the potential to reduce oxidative stress and promote skin whitening. Further investigations will be required to elucidate the mechanisms underlying the antioxidant and antityrosinase activities of these compounds.     

YAG激光照射对高山被孢霉花生四烯酸产量的影响

花生四烯酸产生菌高山被孢霉的孢子在时间为8min,距离为10cm的YAG激光剂量照射下,其致死率为75％－80％,以该剂量反复进行照射及菌种筛选,得到其最高生物量28.6g/L,油脂11.04g/L,3.10g/L的突变株T105,比对照菌株的AA产量及油脂量分别提高了2．95倍和1．71倍。通过对突变株T105的形态,代谢情况以及继代稳定性进行分析,认为YAG激光诱变育种是获得茶花生四烯酸高产菌株的有效方法。     

Age-related plumage differences of Dunlins along the East Asian-Australasian Flyway

ABSTRACT.   For some populations of Dunlins ( Calidris alpina ), determining the age of individuals on the nonbreeding grounds can be difficult. This difficulty arises in part because some populations undergo their primary molt during the boreal summer, leaving adult and first-year Dunlins with similar amounts of abrasion on their primaries. Ageing Dunlins is further complicated by the presence of adults with buff-fringed, inner median coverts in some populations, a feature often used to age juvenile Dunlins. We examined a number of characteristics helpful in the ageing Dunlins at nonbreeding areas along the East Asian-Australasian Flyway, including: (1) the pattern of white fringes on the inner primary coverts, (2) the color of fringes on the inner median wing coverts, (3) the color of the tip on the carpal covert, (4) the presence or absence of a dark subterminal band on tertial or tertial coverts, and (5) remnants of alternate or juvenile plumage on the belly. Our results demonstrate that the pattern of white fringes on the inner primary coverts is an important character for ageing Dunlin along the East Asian-Australasian Flyway. In addition, we found that all characteristics used for ageing fade with time, and that breeding adults along the East Asian-Australasian Flyway are more difficult to age than adults elsewhere, in part due to the presence of "adult buff" coverts (ABCs) and in part because of the early timing of primary molt. Finally, we suggest that the presence of ABCs might be useful for differentiating the two Dunlin subspecies ( C. a. arcticola and C. a. pacifica ) occurring in Alaska.     

Evolution of floral scent in relation to self-incompatibility and capacity for autonomous self-pollination in the perennial herb Arabis alpina

Background and AimsThe transition from outcrossing to selfing is a frequent evolutionary shift in flowering plants and is predicted to result in reduced allocation to pollinator attraction if plants can self-pollinate autonomously. The evolution of selfing is associated with reduced visual floral signalling in many systems, but effects on floral scent have received less attention. We compared multiple populations of the arctic–alpine herb Arabis alpina (Brassicaceae), and asked whether the transition from self-incompatibility to self-compatibility has been associated with reduced visual and chemical floral signalling. We further examined whether floral signalling differ between self-compatible populations with low and high capacity for autonomous self-pollination, as would be expected if benefits of signalling decrease with reduced dependence on pollinators for pollen transfer.MethodsIn a common garden we documented flower size and floral scent emission rate and composition in eight self-compatible and nine self-incompatible A. alpina populations. These included self-compatible Scandinavian populations with high capacity for autonomous self-pollination, self-compatible populations with low capacity for autonomous self-pollination from France and Spain, and self-incompatible populations from Italy and Greece.Key ResultsThe self-compatible populations produced smaller and less scented flowers than the self-incompatible populations. However, flower size and scent emission rate did not differ between self-compatible populations with high and low capacity for autonomous self-pollination. Floral scent composition differed between self-compatible and self-incompatible populations, but also varied substantially among populations within the two categories.ConclusionsOur study demonstrates extensive variation in floral scent among populations of a geographically widespread species. Contrary to expectation, floral signalling did not differ between self-compatible populations with high and low capacity for autonomous self-pollination, indicating that dependence on pollinator attraction can only partly explain variation in floral signalling. Additional variation may reflect adaptation to other aspects of local environments, genetic drift, or a combination of these processes.     

利用甘蔗糖蜜发酵生产花生四烯酸的研究

通过培养高山被孢霉利用糖蜜来发酵生产花生四烯酸(ARA),研究了不同甘蔗糖蜜预处理方法对ARA发酵生产的影响。研究表明:H2SO4法是最利于ARA发酵生产的糖蜜预处理方法。利用预处理的甘蔗糖蜜发酵生产ARA,通过单因素实验设计,确定了最优的培养条件,包括初始还原糖80 g/L,N源6 g/L,接种量20%,初始pH6.0和培养温度25℃,在此条件下发酵,干细胞质量、油脂含量、ARA产量和糖利用率分别达到28.5 g/L、11.7g/L、3.68 g/L和94.5%。     

Changes in reciprocal herkogamy during the tristyly-distyly transition in Oxalis alpina increase efficiency in pollen transfer

Although the spatial separation of sexual organs within a flower (herkogamy) has been interpreted as a mechanism that promotes efficient pollen transfer, there have been few attempts to relate variation in herkogamy to probabilities of pollen flow. Here, we used a heterostylous species with variation in reciprocal herkogamy to test this hypothesis. We measured legitimate and illegitimate pollen flow with fluorescent dyes in four selected populations of Oxalis alpina corresponding to the extremes of a previously reported evolutionary gradient from tristyly to distyly. After the breakdown of tristyly, the observed increment in reciprocal herkogamy between the long and short morphs was associated with a 30% increase in the proportion of dye received from compatible illegitimate pollinations. In all populations, the most likely effective pollen vectors were two Heterosarus bee species. Our results support the adaptive value of reciprocal herkogamy in promoting efficient pollen transfer in heterostylous species.     

高山被孢霉亚甲基四氢叶酸脱氢酶的克隆、表达和功能鉴定

叶酸代谢途径中的亚甲基四氢叶酸脱氢酶（MTHFD）可将5,10-亚甲基四氢叶酸氧化为5,10-甲炔基四氢叶酸,此过程会生成NADH或NADPH。对高山被孢霉中的MTHFD基因进行克隆、表达和功能鉴定,可进一步阐明脂质合成所需还原力NADPH的来源。首先对MTHFD序列进行分析,并以pET28a（+）质粒为载体构建了MTHFD的表达载体,然后转化至大肠杆菌BL21中进行诱导表达。进一步利用Ni金属螯合层析纯化目的蛋白,采用比色法分析酶反应产物,表明纯化蛋白质具有MTHFD活性。高山被孢霉MTHFD对NAD⁺和NADP⁺均具有催化能力,但更偏好于将NADP⁺转化为NADPH。最后对高山被孢霉进行发酵培养,发现MTHFD的转录水平在脂质开始积累后发生了明显的上调,表明MTHFD在高山被孢霉脂质合成过程中发挥重要作用,很可能是脂质合成所需NADPH的关键来源。这为对高山被孢霉进行分子改造,使之成为高产各种多不饱和脂肪酸的细胞工程提供了理论依据。     

花生四烯酸高产菌M6的鉴定

为鉴定花生四烯酸高产菌M6考查了M6的形态、生理特征及其核糖体18S rDNA序列。M6菌落为白色,菌落初期很薄,圆形,然后一层层扩展,形成花瓣状,并长出棉花状菌丝。显微镜下观察,菌丝体内有较多的油脂颗粒。菌株M6在4℃低温下和25℃温度下都可以生长,M6菌体油脂的脂肪酸气相色谱分析显示M6可以产生花生四烯酸。M6的18S rDNA的部分序列分析表明其与高山被孢霉同源性最高,达99%。根据M6的形态、生理特征及其核糖体18S rDNA的序列的分析鉴定M6是高山被孢霉。