基于地统计学和GIS的苜蓿斑蚜种群空间结构分析和分布模拟

运用地理信息系统(GIS)和地统计学方法对宁夏南部固原市原州区不同时期苜蓿斑蚜(Therioaphis trifolii)种群的空间结构进行了分析,并采用普通克立格插值法模拟了苜蓿斑蚜种群空间分布.结果表明:不同时期苜蓿斑蚜种群存在空间相关性,其半变异函数曲线均为指数型,空间格局呈聚集分布,空间变异成分的变化范围为34.13%~48.77%,空间相关范围为8.751~12.049km,聚集程度和方向有从西南向东北方向聚集的趋势.空间分布模拟图能较好地从时间、空间两个角度直观地分析不同时期苜蓿斑蚜种群的动态变化,易于确定同一时期苜蓿斑蚜的发生位置和发生程度.     

Rapid development of molecular markers by next-generation sequencing linked to a gene conferring phomopsis stem blight disease resistance for marker-assisted selection in lupin (Lupinus angustifolius L.) breeding

Selection for phomopsis stem blight disease (PSB) resistance is one of the key objectives in lupin (Lupinus angustifolius L.) breeding programs. A cross was made between cultivar Tanjil (resistant to PSB) and Unicrop (susceptible). The progeny was advanced into F₈ recombinant inbred lines (RILs). The RIL population was phenotyped for PSB disease resistance. Twenty plants from the RIL population representing disease resistance and susceptibility was subjected to next-generation sequencing (NGS)-based restriction site-associated DNA sequencing on the NGS platform Solexa HiSeq2000, which generated 7,241 single nucleotide polymorphisms (SNPs). Thirty-three SNP markers showed the correlation between the marker genotypes and the PSB disease phenotype on the 20 representative plants, which were considered as candidate markers linked to a putative R gene for PSB resistance. Seven candidate markers were converted into sequence-specific PCR markers, which were designated as PhtjM1, PhtjM2, PhtjM3, PhtjM4, PhtjM5, PhtjM6 and PhtjM7. Linkage analysis of the disease phenotyping data and marker genotyping data on a F₈ population containing 187 RILs confirmed that all the seven converted markers were associated with the putative R gene within the genetic distance of 2.1 CentiMorgan (cM). One of the PCR markers, PhtjM3, co-segregated with the R gene. The seven established PCR markers were tested in the 26 historical and current commercial cultivars released in Australia. The numbers of “false positives” (showing the resistance marker allele band but lack of the putative R gene) for each of the seven PCR markers ranged from nil to eight. Markers PhtjM4 and PhtjM7 are recommended in marker-assisted selection for PSB resistance in the Australian national lupin breeding program due to its wide applicability on breeding germplasm and close linkage to the putative R gene. The results demonstrated that application of NGS technology is a rapid and cost-effective approach in development of markers for molecular plant breeding.     

Concepts and analysis of mass extinction with the late Ordovician event as an example

Twelve groups of fossils, including graptolites, brachiopods, nautiloids, trilobites, corals, crinoids, bryozoans, conodonts, ostracods, gastropods, chitinozoans, and acritarchs expired in different but substantial magnitude and global extent during the late Caradoc to latest Ashgill. It indicates a multiple‐episodic mass extinction containing the possible Prologue (late Caradoc), Climax episode (Rawtheyan) and Epilogue (late Hirnantian). The main causes of this mass extinction are recognized as a global sea‐level lowering in the climax and remarkable rapid rise at the final, and global cooling. The Chinese data, especially from the South China Paleoplate, are evaluated first. They are significant for explaining this global bioevent.     

Label-Free Enrichment of Adrenal Cortical Progenitor Cells Using Inertial Microfluidics

Passive and label-free isolation of viable target cells based on intrinsic biophysical cellular properties would allow for cost savings in applications where molecular biomarkers are known as well as potentially enable the separation of cells with little-to-no known molecular biomarkers. We have demonstrated the purification of adrenal cortical progenitor cells from digestions of murine adrenal glands utilizing hydrodynamic inertial lift forces that single cells and multicellular clusters differentially experience as they flow through a microchannel. Fluorescence staining, along with gene expression measurements, confirmed that populations of cells collected in different outlets were distinct from one another. Furthermore, primary murine cells processed through the device remained highly viable and could be cultured for 10 days in vitro. The proposed target cell isolation technique can provide a practical means to collect significant quantities of viable intact cells required to translate stem cell biology to regenerative medicine in a simple label-free manner.     

A physiological dose of estradiol with progesterone affects striatum biogenic amines

The acute effect of estradiol and progesterone on dopamine and serotonin metabolism in rat striatum was studied. One subcutaneous injection of 17 beta-estradiol (300 ng) and progesterone (150 micrograms) into intact male rats increased plasma levels of these steroids, while testosterone, corticosterone, and estrone remained unchanged. Dehydroepiandrosterone, androstane-3 beta, 17 beta-diol and dihydrotestosterone remained undetectably low. Prolactin decreased and androstane-3 alpha, 17 beta-diol, and 17-OH progesterone increased, but less than estradiol and progesterone. Peak levels of striatal dopamine, dihydroxyphenylacetic acid, and homovanillic acid were observed 15-45 min after steroid injection with a return to control values after 45-60 min, while serotonin and 5-hydroxyindoleacetic acid levels were slightly decreased. An injection of estradiol (70 ng) with progesterone (70 micrograms) to ovariectomized female rats left plasma prolactin levels unchanged, while striatum dopamine and serotonin as well as their metabolite concentrations peaked 15-60 min after steroid injection and returned to control values after 45-75 min. To allow for a better comparison of the action of these steroids, the effect of estradiol or progesterone alone and in combination on the brain of ovariectomized rats was compared in the same experiment. A similar increase in metabolites of dopamine levels was observed after these steroids alone or in combination, while dopamine levels were increased only after progesterone alone or in combination with estradiol. An injection of estradiol or progesterone to ovariectomized rats led to peak steroid concentrations at approximately the same time in the brain and plasma. In addition, plasma and brain steroid levels were significantly correlated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reversibility and "pH-T phase diagrams" of Rapana venosa hemocyanin and its structural subunits

We have studied the stability and reassociation behaviour of native molecules of Rapana venosa hemocyanin and its two subunits, termed RvH1 and RvH2. In the presence of different concentrations of Ca(2+) and Mg(2+) ions and pH values, the subunits differ not only in their reassociation behaviour, but also in their formation of helical tubules and multidecamers. RvH1 revealed a greater stability at higher pH values compared to RvH2. Overall, the stability of reassociated RvH and its structural subunits was found to be pH-dependent. The increasing stability of native Hc and its subunits, shown by pH-induced CD transitions (acid and alkaline denaturation), can be explained with the formation of quaternary structure. The absence of a Cotton effect at temperatures 20-40 degrees C in the pH-transition curves of RvH2 indicates that this subunit is stabilized by additional "factors", e.g.: non-ionic/hydrophobic stabilization and interactions of carbohydrate moieties. A similar behaviour was observed for the T-transition curves in a wide pH interval for RvH and its structural subunits. At higher temperatures, many of the secondary structural elements are preserved especially at neutral pH, even at extreme high temperatures above 90 degrees C the protein structures resemble a "globule state".     

Oviposition of the Colorado potato beetle (Leptinotarsa decemlineata) and natural predation on its egg masses in Bt-expressing fields

Generalist predators are relevant natural enemies of the Colorado potato beetle (CPB) in Europe. In fields of insect resistant genetically modified plants (GMPs), predators could be exposed to toxins either directly (e.g., via pollen), or indirectly through feeding on herbivorous prey. Hence, they represent an important functional group to consider when studying environmental impacts of GMPs. CPB females show a ‘bet-hedging’ strategy in spatial and temporal distribution of eggs, through which the species tries to minimize the risks of progeny loss due to adverse conditions. Experimental fields of GM eggplants expressing Cry3Bb toxin and potatoes expressing Cry1Ab toxin were set up. CPB egg masses were counted on naturally infested plants at four time points during the field season of each crop. To assess predation, newly deposited egg masses were marked at the same dates. Daily visual observations were conducted recording the numbers of intact or preyed eggs and neonate larvae. In both cases, oviposition was similar between GM and control plots, as the number of egg masses per plant and the number of eggs per mass did not differ significantly between treatments. A statistical analysis of the spatial distribution of egg masses revealed a similar aggregation in the potato field, whereas in the eggplant field, the variance of the number of egg masses per plant was smaller than expected in GMP plots. The predation rate was similar between treatments. These results suggest that the ecological function of natural predation on CPB eggs in GM plots was not impaired.     

Construction of recombinant plasmids containing rat thyroglobulin mRNA sequences

Two plasmids containing rat thyroglobulin cDNA sequences have been constructed and characterized. A plasmid with a 500-bp insert (pRT6) was isolated and identified as thyroglobulin-specific on the basis of the tissue specificity of the inserted sequence and of its ability to retain thyroglobulin mRNA on a nitrocellulose filter. The cDNA insert in pRT6 was subsequently used to screen a rat thyroid cDNA library constructed with large cDNA. A plasmid was found containing a 1700-bp insert. The polarity and the fidelity of the insert is demonstrated by S1 mapping.