Pedigree,marker recruitment,and genetic diversity of modern sugarcane cultivars in China and the United States

Sugarcane (Saccharum spp) is an important crop for both sugar and biofuel production. However, the sugarcane breeding process has resulted in modern sugarcane cultivars with a narrow genetic basis. To broaden the genetic basis and promote international collaborations in sugarcane cultivar development, we documented the peidgrees of representative sugarcane culativars widely used in China and the United States of America (USA), recruited more than six thousand simple sequence repeat (SSR) markers for sugarcane, and assessed the genetic diversity and relationships beween representative sugarcane cultivars and their potential ancestry accessions. The SSR gentoyping results indicated that both the USA and Chiniese cultivars had low genetic diversity, specifically the Chinese cultivars. The USA sugarcane cultivars experienced high presure of selection for sugar content as they had the closest relationship with S. officinarum, followed by Chinese cultivars, S. robustum, and S. spontaneum. The sugarcane accessions assessed could be divided into five and four groups through cluster and principal component analysis, respectively. S. spontaneum as a potential ancestor contributing to the stress tolerance of sugarcane cultivars was grouped into distinct clusters, and S. officinarum was grouped with sugarcane cultivars in both countries. S. robustum did not seem to contribute to the sugarcane cultivar development in China, but may have contributed to the USA cultivar development. This study not only provided a collection of easy to use SSR markers, but also detailed genetic diversity and relationship among the cultivars in the two counties, which will be referable to promote international collaboration and broaden the genetic basis of sugarcane cultivars.     

柑桔黄斑落叶病病原菌鉴定

正柑桔(Citrus reticulata Blanco)是著名的热带、亚热带水果。位于我国南疆的广西,属于亚热带季风气候,是种植柑桔最适宜区或适宜区,柑桔也是广西一大优势水果产业,是广西出口东盟的主要农产品。柑桔黄斑落叶病是近年来在我国广西地区发生的一种新病害。该病害主要危害秋梢和春梢叶片,形成不规则黄斑,严重的可造成整个叶片脱     

16个苹果品种非浓缩还原汁的理化特征分析

【目的】通过研究16种苹果非浓缩还原汁（not from concentrate,NFC）果汁的8项理化指标,利用相关性分析明确指标间的关系,以简化NFC果汁品质的评价指标。此外,利用多元数据处理对不同品种苹果NFC果汁进行归类,以找到NFC果汁生产中制汁和智能复配的替代品种,为NFC果汁产业发展提供理论参考。【方法】以16个苹果品种为试材,经榨汁、灭酶、巴杀、热灌装等单元操作制备NFC果汁。通过测定16种果汁的可溶性固形物含量、pH、可滴定酸含量、固酸比、表观黏度、浊度、总酚含量及色泽品质（L^*、a^*、b^*、C^*、h°）指标,采用单因素方差分析与相关性分析对测定结果进行显著性和相关性分析。此外,利用主成分分析（PCA）、线性判别分析（LDA）、聚类分析（CA）多元数据处理方法,对16种果汁的理化指标数据矩阵进行分析,获得16个苹果品种的综合品质分类。【结果】16种苹果汁的各项理化指标均存在显著差异,其中,‘新世界’的可溶性固形物含量和浊度最高,分别为15.7 °Brix和3 720 NTU;‘澳洲青苹’的pH最低,为2.74;‘红玉’的可滴定酸含量最高,为9.6 g·L^-1（苹果酸当量）;‘秦艳’的固酸比最高,为39.24;‘元帅’‘恩派’‘桔苹’都表现出最高的表观黏度,均为3.75 mPa·s;‘富士’的总酚含量最高,为775.94 mg·L^-1（没食子酸当量）。果汁pH与固酸比（R²=0.844）、浊度与L^*值（R²=0.967）均呈极显著正相关关系（P<0.01）,pH与可滴定酸含量（R²=-0.896）、固酸比与可滴定酸含量（R²=-0.918）均呈极显著负相关关系（P<0.01）。PCA、LDA和CA的分类结果完全一致,16个品种的NFC苹果汁可分为3大类,同一大类中各品种之间不同理化指标差异较小,品质、色泽十分接近,可作为NFC果汁生产和智能复配的可替代品种。【结论】可溶性固形物含量、可滴定酸含量、色值、表观黏度、总酚含量5项理化指标,可全面反映NFC果汁的品质。在果汁品质分类中,‘玉华早富’和‘乔纳金’归为一类,‘新世界’和‘秦冠’归为一类,‘新红星’‘富士’‘桔苹’‘自由’‘秦艳’‘澳洲青苹’、‘秋香’‘粉红女士’‘元帅’‘恩派’‘凉香’‘红玉’归为一类,同一类别中NFC果汁品质接近,可作为制汁和智能复配的替代品种。     

Characterization and expression of <Emphasis Type="Italic">lin-28a</Emphasis> involved in <Emphasis Type="Italic">lin28/let-7</Emphasis>signal pathway during early development of <Emphasis Type="Italic">P. olivaceus</Emphasis>

Heterochronic lin-28 is a conserved RNA-binding protein that plays a key role in the timing of developmental events in organisms. As a crucial heterochronic gene, the protein controls developmental events of the second of four larval stages in Caenorhabditi elegans. Heterochronic let-7 miRNAs are often present in various species and highly conserved in sequence and biological function and are required for various biological processes. Previous studies showed that ten let-7 miRNAs were identified in the Japanese flounder (Paralichthys olivaceus) and that they were primarily expressed during metamorphosis. In this study, we clone and characterize the lin-28a gene from P. olivaceus and exhibit its dynamic expression pattern at different developmental stages and various adult tissues. The results show that the P. olivaceus lin-28a gene has high sequence similarity with other species and is highly expressed in the embryonic stage but weakly expressed in the larval stage. In addition, lin-28a overexpression causes cell proliferation and significantly promotes the levels of pre-let-7a and pre-let-7d while markedly depressing let-7a and let-7d expression in FEC (Flounder Embryonic Cell), which indicate that lin-28 possibly blocks the maturation of let-7 miRNAs. Additionally, lin-28a is identified as a target gene of let-7 miRNAs, and let-7 miRNAs directly regulate lin-28a expression by targeting its 3′ UTR. Taken together, lin-28a along with let-7 miRNA participates in a lin-28/let-7 axis pathway that regulates cell division and timing of embryonic and metamorphic events in P. olivaceus.     

滴灌夏玉米土壤水分与蒸散量SIMDualKc模型估算

为研究西北半干旱地区作物蒸腾和土壤蒸发规律,以及土壤蒸发量占蒸散量的比例(简称蒸发占比),开展2 a夏玉米滴灌控水试验,设置正常灌水(W1)、适度水分亏缺(W2)和中度水分亏缺(W3)3个灌水水平.采用W2实测土壤水分数据对SIMDualKc模型进行参数率定,并采用W1和W3实测土壤水分数据对模型进行验证;进一步基于SIMDualKc模型对不同水分供应的土壤水分胁迫系数、土壤蒸发量、植株蒸腾和蒸散量进行定量模拟分析.结果表明,SIMDualKc模型可以较好地模拟西北半干旱区滴灌夏玉米不同水分供应条件下的土壤水分动态变化过程,实测值与模型预测值有较好的一致性(R2＞0.88,RMSE＜5％);夏玉米生长期,模型能较好地估算不同水分供应的土壤水分胁迫系数、土壤蒸发量和植株蒸腾.土壤蒸发主要集中在生育前期,而生育中期较低,后期略微升高.植物蒸腾主要集中在快速生长期和生长中期,整个生育期呈先增大后减小的趋势.蒸散量随着土壤蒸发和植物蒸腾的变化而变化,前期主要受土壤蒸发的影响,快速生长期、生长中期和后期主要受植物蒸腾的影响.Wl～W3处理土壤蒸发量为78.1～100.2 mm,植株蒸腾为221.8～293.3 mm,蒸散量为299.3～383.0 mm,蒸发占比为24.1％～28.7％.研究可为西北半干旱地区制定合理的夏玉米滴灌制度和灌溉决策提供理论依据.     

Evaluation of anti-stabbing performance of fabric layers woven with various hybrid yarns under different fabric conditions

Various types of special fibers are used for human body protection, mostly in the form of fiber-reinforced composites. These composites are made of special fibers and matrix resin; however, they are often not comfortable for the wearer due to the lack of flexibility and air permeability. This study focuses on an evaluation of human body protective performance against stabbing for various special fibers such as aramid, basalt, and steel fibers, being utilized in cotton hybrid forms. These hybrid forms are designed to improve wearer comfort, while maintaining adequate anti-stab resistance. Specimens prepared with various fabric densities are tested in terms of anti-stabbing performance, according to the NIJ standard. In addition, we investigate the influence of factors such as fiber type, the number of fabric layers, fabric weight, and fabric density on anti-stabbing performance. Results show that the penetration depth of the impactor, which punctures and protrudes through the specimens, decreases with the number of layers, the thickness, and the mass of the armor sample; however, these factors have different relationships according to the material type. Consequently an objective evaluation of anti-stabbing performance is needed. We suggest an anti-stabbing index that can be applied as a criterion to evaluate the antistabbing performance of various specimens woven with special fibers under different fabric conditions. Using the new index, anti-stabbing performances of various specimens can be compared and raw material and fabric conditions that offer the most efficient anti-stabbing performance can be selected.     

全球禽病概览

伴随国内家禽养殖业的快速发展,各种禽病层出不穷,其危害也越来越严重。保守估计,每年我国家禽因各类疾病引起的死亡率在15%～20%,造成了很大的经济损失。同时,一些新的禽病和病原的出现更是给养禽业的健康发展带来了挑战。让我们重新审视这些全球范围内最常见的禽病及其对世界贸易的影响和防治进展,了解美国蛋鸡业面临的主要的疾病困扰以及采取的应对措施,希望能在国内禽病控制方面给业界提供一点参考和启发。     

新旧《动物检疫管理办法》对照解读

<正>2010年3月1日起,农业部颁布了新的《动物检疫管理办法》(以下简称《办法》(新)),取代了2002年的版本(以下简称《办法》(旧))。《办法》(新)是农业部依据2007年新修订的《动物防疫法》有关条款的变更、适应国家兽医体制改革的趋势、联系当下     

Contact Toxicity and Repellency of the Main Components From the Essential Oil of Clausena anisum-olens Against Two Stored Product Insects

The essential oil of Clausena anisum-olens (Blanco) Merr. showed strong contact toxicity and repellency against Lasioderma serricorne and Liposcelis bostrychophila adults. The components of the essential oil obtained by hydrodistillation were determined by gas chromatography-mass spectrometry. It was found that the main components were myristicin (36.87%), terpinolene (13.26%), p-cymene-8-ol (12.38%), and 3-carene (3.88%). Myristicin and p-cymene-8-ol were separated by silica gel column chromatography, and their molecular structures were confirmed by means of physicochemical and spectrometric analysis. Myristicin and p-cymene-8-ol showed strong contact toxicity against L. serricorne (LD₅₀ = 18.96 and 39.68 μg per adult) and Li. bostrychophila (LD₅₀ = 20.41 and 35.66 μg per adult). The essential oil acting against the two grain storage insects showed LD₅₀ values of 12.44 and 74.46 μg per adult, respectively. Myristicin and p-cymene-8-ol have strong repellent toxicity to Li. bostrychophila.     

壳寡糖季铵盐衍生物纳米银的合成及其诱导烟株抗烟草花叶病毒活性

为开发符合高效、低毒且环境友好的新型烟草花叶病毒(TMV)抑制剂,以具有季铵盐结构的新型壳寡糖季铵盐衍生物为还原剂和稳定剂,合成了壳寡糖季铵盐衍生物纳米银溶液,并研究了不同浓度该纳米银溶液诱导烟株产生抗TMV的活性。结果表明:所合成的壳寡糖季铵盐衍生物纳米银溶液在透射电镜(TEM)下显示分布较均匀,粒径主要集中在7~12 nm。在珊西烟上以25μg/m L的壳寡糖季铵盐衍生物纳米银溶液对枯斑的抑制效果最好,抑制率为74.0%,比50μg/m L壳寡糖溶液和2%宁南霉素水剂分别高41.5%和24.4%;对于普通烟K326,壳寡糖季铵盐衍生物纳米银溶液可缓解被病毒侵染的烟草叶绿素含量的下降幅度,提高叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(PPO)的活性,降低丙二醛(MDA)的含量,提高可溶性蛋白含量。表明壳寡糖季铵盐纳米银溶液可提高烟株对TMV的抗病性。