More than multiple introductions: Multiple taxa contribute to the genesis of the invasive California’s wild artichoke thistle

The history of some invasive species is so complex that their origins can be difficult to determine. One example of such invasive species is the California invasive known as “wild artichoke thistle” (Cynara cardunculus var. sylvestris), found in natural and disturbed ecosystems. Wild artichoke thistle is a Mediterranean native and the progenitor of two domesticated horticultural taxa, artichoke and cardoon. Different hypotheses regarding the origins of California plants have included introductions by 19th century Italian immigrants and the de-domestication (evolutionary reversion to wild-type morphology) of feral (escaped, free-living) cultivars. Using microsatellite markers, we compared the genetic constitutions of 12 artichoke thistle populations in California with possible progenitor populations: 17 Spanish and Italian wild populations and eight different artichoke and cardoon cultivars. Each California population was compared with its putative progenitors using STRUCTURE analysis. Our results suggest that California's artichoke thistle populations are polyphyletic. Surprisingly, two-thirds of California's populations closely matched populations from the Iberian Peninsula. Three populations matched domesticated artichoke. One population appears to have wild and cultivar hybrid ancestry. Alleles specific to Italian populations were found at low frequencies in some California plants, suggesting that Italian wild plants may have been in California, but have left a trivial genetic legacy. Given that the de-domesticated plants in this study appear to be as invasive as the wild taxon, we conclude with a discussion of the role that ferality and de-domestication may have in plant invasions.     

Partitioning of Nitrogen Derived from N2 Fixation and Reserves in Nodulated Medicago sativa L. During Regrowth

Nodul{macron}ted alfalfa plants were grown hydroponically. Inorder to quantify N₂ fixation and remobilization of N reservesduring regrowth the plants were pulse-chase-labelled with ¹⁵N.Starch and ethanol-soluble sugar contents were analysed to examinechanges associated with those of N compounds. Shoot removalcaused a severe decline in N₂ fixation and starch reserves within6 d after cutting. The tap root was the major storage site formetabolizable carbohydrate compounds used for regrowth; initiallyits starch content decreased and after 14 d started to recoverreaching 50% of the initial value on day 24. Recovery of N₂fixation followed the same pattern as shoot regrowth. Afteran initial decline during the first 10 d following shoot removal,the N₂ fixation, leaf area and shoot dry weight increased sorapidly that their levels on day 24 exceeded initial values.Distribution of ¹⁵N within the plant clearly showed that a significantamount of endogenous nitrogen in the roots was used by regrowingshoots. The greatest use of N reserves (about 80% of N incrementin the regrowing shoot) occurred during the first 10 d and thencompensated for the low N₂ fixation. The distribution of N derivedeither from fixation or from reserves of source organs (taproots and lateral roots) clearly showed that shoots are thestronger sink for nitrogen during regrowth. In non-defoliatedplants, the tap roots and stems were weak sinks for N from reserves.By contrast, relative distribution within the plant of N assimilatedin nodules was unaffected by defoliation treatment. Key words: Medicago sativa L., N₂ fixation, N remobilization, N₂ partitioning, regrowth     

大麝鼩韩国种群与俄罗斯远东种群之间的遗传分化:基于线粒体Cyt b 基因的分析

为重新分析韩国大麝鼩种群与相邻的俄罗斯远东种群之间的遗传分化情况,我们获得9 条来自韩国4 个地点和俄罗斯3 个地点的大麝鼩线粒体细胞色素b 基因(Cyt b)全序列,并将其与来自GenBank 的4 条Cyt b 全序列和4 条Cyt b 部分序列进行比较。结果发现韩国的大麝鼩并非只有一种基因型,因此,在利用Cyt b 部分序列进行种群遗传学分析时需格外注意。基于Cyt b 全序列分析,发现韩国的大麝鼩与俄罗斯远东地区的大麝鼩之间存在1.08% 的平均JC 距离和7 个位点的差异,推测韩国的大麝鼩与俄罗斯远东地区的大麝鼩在包括末次冰盛期在内的很长时期都没有进行过遗传交流。目前的测序结果不支持当前认为大麝鼩为单系群的亚种分类理论,支持韩国大麝鼩是C. l. thomasi 亚种的分类理论,但还需进一步对中国东北地区的样品进行测序分析后才能最终确认。     

用RFLP方法研究陕西省主要小麦品种遗传多样性及其演变

研究用ＲＦＬＰ方法,对我国主要小麦产区,陕西省４０年代以来广为种植的小麦品种的遗传多样性进行了研究,结果表明,占总带数２６．２％的ＨＩＮＤＩＩＩ酶的ＲＦＬＰ带具有遗传多态性。２４个小麦品种平均遗传相似系数为０．９４８。５３．８％的探针显示了多态性。平均多态性信息含量指数为０．２５２。陕西省小麦品种遗传多样性以７０年代为最高,之后开始降低。     

Molecular cloning and expression pattern of 14-3-3ζ from the malaria vector, Anopheles sinensis

14-3-3 proteins are known to play a pivotal role in cell survival, apoptosis and signal transduction. The 14-3-3ζ isoform has been cloned and characterized from many eukaryotic organisms, including the fruit fly and silkworm. However, no study on mosquito 14-3-3 has been reported to date. In an attempt to investigate the function of 14-3-3 in midgut epithelial cells undergoing apoptosis, a cDNA library was generated from the malaria vector, Anopheles sinensis , which was treated with apoptosis-inducing Actinomycin-D. We were able to identify and obtain A. sinensis 14-3-3ζ cDNA ( Ansi14-3-3ζ ) from expressed sequence tags (EST) analysis after conducting massive sequencing of the A. sinensis cDNA library. Ansi14-3-3ζ has very high homology to 14-3-3 homologs of various insects, such as Anopheles gambiae (100%), Aedes aegypti (100%), Drosophila melanogaster (96%), Bombyx mori (93%), Apis mellifera (93%) and Mus musculus (81%), indicating that mosquito 14-3-3ζ is a highly conserved gene in diverse organisms. Analysis of temporal expression patterns showed that Ansi14-3-3ζ mRNA is highly expressed in egg, early pupae and adult stages and is also expressed, although at low levels, in fourth instar larvae and late pupae. In response to two immune elicitors (lipopolysaccharide and laminarin), no striking induction of 14-3-3ζ mRNA was observed in A. sinensis . Further studies of the precise biological function, inducibility and subcellular distribution of 14-3-3ζ are required in Plasmodium invasion-induced apoptotic midgut cells in A. sinensis in the context of the Time Bomb model.     

Effects of Cricket Extract on Lipid Metabolism and Body Fat Content in High- Fat Diet Fed Rats

The effect of cricket extract on high‐fat diet fed rat was observed. It was shown that cricket extract prevented the increment of body weight by high‐fat diet. The extract also decreased the value of AST in liver. The most significant effect of the extract was shown on lipid metabolism. The contents of total lipid and total cholesterol in liver and feces were reduced by the extract on dose‐dependent. These statistically significant results were clear in 3% extract treated group (HFD3) while were slight in 1% extract treated group (HFD1). The same result was also shown in body fat content.