棉花耐盐相关种质资源遗传多样性分析

为了解我国棉花耐盐相关种质资源的遗传变异,利用88对SSR引物对23份棉花耐盐材料和24份盐敏感材料进行遗传多样性分析。88个SSR位点在47份材料中共检测出338个等位基因变异,平均每个位点有3.841个;其中耐盐材料中检测出333个,盐敏感材料中检测出312个。耐盐材料的位点多态信息含量(PIC)、每个位点的有效等位基因数(Ne)、基因型多样性(H′)分别为0.613、2.929和1.083,盐敏感材料的PIC、Ne、H′分别为0.605、2.883和1.071。耐盐材料和盐敏感材料的Jaccard相似性系数分别在0.530–0.979和0.525–0.878之间,遗传相似性系数总体平均值接近,但耐盐材料的变化幅度更大。用类平均法(UPGMA)聚类将47份材料分成3个类群。总体而言,大多数材料之间的遗传相似性系数较高,表明我国陆地棉耐盐相关种质资源遗传基础狭窄。本结果为棉花耐盐育种中亲本的选配和优势组合的预测以及耐盐资源的合理利用等提供了基础资料。     

Toxicological Evaluation of Lactase Derived from Recombinant Pichia pastoris

A recombinant lactase was expressed in Pichia pastoris, resulting in enzymatic activity of 3600 U/mL in a 5 L fermenter. The lactase product was subjected to a series of toxicological tests to determine its safety for use as an enzyme preparation in the dairy industry. This recombinant lactase had the highest activity of all recombinant strains reported thus far. Acute oral toxicity, mutagenicity, genotoxic, and subchronic toxicity tests performed in rats and mice showed no death in any groups. The lethal dose 50% (LD₅₀) based on the acute oral toxicity study is greater than 30 mL/kg body weight, which is in accordance with the 1500 L milk consumption of a 50 kg human daily. The lactase showed no mutagenic activity in the Ames test or a mouse sperm abnormality test at levels of up to 5 mg/plate and 1250 mg/kg body weight, respectively. It also showed no genetic toxicology in a bone marrow cell micronucleus test at levels of up to 1250 mg/kg body weight. A 90-day subchronic repeated toxicity study via the diet with lactase levels up to 1646 mg/kg (1000-fold greater than the mean human exposure) did not show any treatment-related significant toxicological effects on body weight, food consumption, organ weights, hematological and clinical chemistry, or histopathology compared to the control groups. This toxicological evaluation system is comprehensive and can be used in the safety evaluation of other enzyme preparations. The lactase showed no acute, mutagenic, genetic, or subchronic toxicity under our evaluation system.     

Draft genome sequence of strain HIMB100, a cultured representative of the SAR116 clade of marine Alphaproteobacteria

Strain HIMB100 is a planktonic marine bacterium in the class Alphaproteobacteria. This strain is of interest because it is one of the first known isolates from a globally ubiquitous clade of marine bacteria known as SAR116 within the family Rhodospirillaceae. Here we describe preliminary features of the organism, together with the draft genome sequence and annotation. This is the second genome sequence of a member of the SAR116 clade. The 2,458,945 bp genome contains 2,334 protein-coding and 42 RNA genes.     

Sickle cell disease in mice is associated with sensitization of sensory nerve fibers

The pain phenotype in sickle cell disease (SCD) patients is highly variable. A small percentage of SCD patients experience many vaso-occlusive crises/year, 5% of patients account for over 30% of pain episodes, while 39% report few episodes of severe pain. Clearly, a better understanding of the pathobiology of SCD is needed to improve its therapy. Humanized sickle cell mice recapitulate several phenotypes of SCD patients and provide a model for the study of SCD pain. Researchers have shown that one strain of humanized SCD mice, the BERK strain, has abnormal pain phenotype. However, the nociception phenotype of another humanized SCD mouse strain, the Townes strain, has not been described. In a large cross-sectional study of BERK and Townes SCD mice, we examined thermosensory response and sensory nerve fiber function using sine-wave electrical stimulation at 2000, 250, and 5 Hz to stimulate preferentially Aβ, Aδ, and C sensory nerve fibers, respectively. We found that BERK and Townes mice, compared to respective controls, had decreases in 2000, 250, and 5 Hz current vocalization thresholds in patterns that suggest sensitization of a broad spectrum of sensory nerve fibers. In addition, the pattern of sensitization of sensory fibers varied according to strain, sex, age, and mouse genotype. In a similarly variable pattern, Townes and BERKs also had significantly altered sensitivity to noxious thermal stimuli in agreement with what has been shown by others. In summary, the analysis of somatosensory function using sine-wave electrical stimulation in humanized sickle cell mice suggests that in SCD, both myelinated and unmyelinated, fibers are sensitized. The pattern of sensory fiber sensitization is distinct from that observed in pain models of neuropathic and inflammatory pain. These findings raise the possibility that sensitization of a broad spectrum of sensory fibers might contribute to the altered and variable nociception phenotype in SCD.     

干旱胁迫下不同抗旱水平陆地棉的叶片蛋白质组学比较研究

为了探讨陆地棉品种抗旱机理,以陆地棉抗旱品种‘中H177’和不抗旱品种‘中S9612’为材料,运用双向电泳结合质谱技术,分析干旱胁迫下不同陆地棉三叶期叶片蛋白质组分差异变化。结果表明:干旱胁迫下,不同陆地棉叶片蛋白表达差异较大;‘中H177’出现30个差异表达蛋白质点,‘中S9612’出现47个差异表达蛋白质点,只在‘中H177’表达差异的蛋白点11个,只在‘中S9612’表达差异的蛋白点28个,差异表达一致蛋白点8个,表达不一致蛋白点11个。质谱共鉴定出43个差异表达蛋白;功能分类分析表明,干旱胁迫蛋白参与光合作用、物质与能量代谢、抗逆相关蛋白、物质运输和活性氧清除;Rubisco活化酶和能量代谢相关蛋白ATP合成酶类表达差异最大。研究结果可以初步为陆地棉抗旱机理的探讨提供一定的理论基础。     

Monitoring ungulates in steep non-forest habitat: a comparison of faecal pellet and helicopter counts

Faecal pellet counts have been widely used to monitor the abundances of introduced ungulates in New Zealand, but ground-based sampling cannot be conducted safely in the steep non-forest habitats that are common in New Zealand's Southern Alps. Helicopter counts may be an effective technique for monitoring ungulates in steep non-forest habitat. We evaluated the relationship between faecal pellet and helicopter counts of ungulates (primarily feral goat Capra hircus) at 12 non-forest sites in the Southern Alps. Within each site we counted the numbers of ungulates from a helicopter on three occasions and the number of intact faecal pellets along 30 transects. Mean observed densities of feral goats derived from helicopter counts ranged from 0.0 to 20.2 km^?2. There was a positive curvilinear (concave down) relationship between faecal pellet and helicopter counts. Compared with faecal pellet counts, helicopter counts were cheaper, could identify ungulate species and provided estimates of absolute density. Helicopter counts are a cost-effective method for monitoring ungulates in the steep non-forest habitats of New Zealand's Southern Alps.     

First-line treatment for chronic myeloid leukemia: dasatinib, nilotinib, or imatinib

Prognostic markers, such as NPM1, Flt3-ITD, and cytogenetic abnormalities have made it possible to formulate aggressive treatment plans for unfavorable acute myeloid leukemia (AML). However, the long-term survival of AML with unfavorable factors remains unsatisfactory. The latest data indicate that the standard dose of daunorubicin (DNR) at 45 mg/m² is inferior to high dose 90 mg/m² for induction therapy. The rates of complete remission and overall survival are significantly better in the high dose induction regimen. New regimens exploring the new liposomal encapsulation of Ara-C and DNR as well as addition of gemtuzumab ozogamicin monoclonal antibody have been studied. New agents, including the nucleoside analogues (clofarabine, sapacitabine, elacytarabine), FLT3 inhibitor (sorafenib), farnesyl-transferase inhibitor (tipifarnib), histone deacetylase inhibitor (vorinostat), lenalidomide, as well as DNA methyltransferase inhibitors (decitabine, azacitidine), were recently reported for AML treatment in the 2009 ASH annual meeting. This review also summarizes the updates of the clinical trials on novel agents including voreloxin, AS1413, behenoylara-C, ARRY520, ribavirin, AZD1152, AZD6244, and terameprocol (EM-1421) from the 2009 ASH annual meeting.     

What determines "suitable habitat" for metapopulation studies? An analysis of environmental gradients and species assemblages in xeric forest openings

? Premise of the study: For metapopulation and metacommunity studies, "suitable habitat" is an area within an otherwise inhospitable matrix in which a species can potentially or does occur. When examining aquatic habitats, for example, this habitat is much easier to define than in terrestrial regions. We tested the assumption that suitable habitat can be delimited in terrestrial ecosystems. ? Methods: We surveyed vascular plant species found in 38 forest openings (open suitable habitats) within a matrix of dry forest (an inhospitable habitat) at three sites in southern Illinois over two growing seasons. We compared species composition and environmental variables between these two habitats at three sites using non-metric multidimensional scaling (NMDS) and analysis of similarity (ANOSIM). ? Key results: Distinctions such as high canopy openness and high soil temperature were common to all forest openings compared with the forest matrix. Differences in canopy openness and soil temperature were correlated with significantly different vegetation between forest openings and forest matrix at each of the three sites. Among the three sites, 9.3-18.9% were forest opening specialists, consisting of 44 taxa, of which the majority were herbaceous forbs. ? Conclusions: The distinction between suitable and unsuitable habitat for some plant species may depend on a few variables, which may not be consistent between sites. This distinction means that there are potentially more situations than previously thought that metapopulation and metacommunity theory may be capable of explaining, meaning that more systems can be studied using a metapopulation context than previously thought.     

Label-free imaging of lipid-droplet intracellular motion in early Drosophila embryos using femtosecond-stimulated Raman loss microscopy

Lipid droplets are complex organelles that exhibit highly dynamic behavior in early Drosophila embryo development. Imaging lipid droplet motion provides a robust platform for the investigation of shuttling by kinesin and dynein motors, but methods for imaging are either destructive or deficient in resolution and penetration to study large populations of droplets in an individual embryo. Here we report real-time imaging and quantification of droplet motion in live embryos using a recently developed technique termed "femtosecond-stimulated Raman loss" microscopy. We captured long-duration time-lapse images of the developing embryo, tracked single droplet motion within large populations of droplets, and measured the velocity and turning frequency of each particle at different apical-to-basal depths and stages of development. To determine whether the quantities for speed and turning rate measured for individual droplets are sufficient to predict the population distributions of droplet density, we simulated droplet motion using a velocity-jump model. This model yielded droplet density distributions that agreed well with experimental observations without any model optimization or unknown parameter estimation, demonstrating the sufficiency of a velocity-jump process for droplet trafficking dynamics in blastoderm embryos.     

Modeling spring habitat requirements of the endangered brown eared pheasant Crossoptilon mantchuricum in the Huanglong Mountains, Shaanxi Province, China

A detailed understanding of the habitat needs of brown eared pheasants (Crossoptilon mantchuricum) is essential for conserving the species. We carried out field surveys in the Huanglong Mountains of Shaanxi Province, China, from March to June in 2007 and 2008. We arrayed a total of 206 grid plots (200 × 200 m) along transects in 2007 and 2008 and quantified a suite of environmental variables for each one. In the optimal logistic regression model, the most important variables for brown eared pheasants were slope degree, tree cover, distance to nearest water, cover and depth of fallen leaves. Hosmer and Leweshow goodness-of-fit tests explained that logistic models for the species were good fits. The model suggested that spring habitat selection of the brown eared pheasant was negatively related to distance to nearest water and slope degree, and positively to cover of trees and cover and depth of fallen leaves. In addition, the observed detected and undetected grids in 2007 did not show significant differences with predictions based on the model. These results showed that the model could well predict the habitat selection of brown eared pheasants. Based on these predictive models, we suggest that habitat management plans incorporating this new information can now focus more effectively on restrictions on the number of tourists entering the nature reserve, prohibition of firewood collection, livestock grazing, and medicinal plant harvesting by local residents in the core areas, protection of mixed forest and sources of the permanent water in the reserve, and use of alternatives to firewood.