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991.
Natalia V. Krylova Anna O. Kravchenko Olga V. Iunikhina Anastasia B. Pott Galina N. Likhatskaya Aleksandra V. Volodko Tatyana S. Zaporozhets Mikhail Y. Shchelkanov Irina M. Yermak 《Marine drugs》2022,20(1)
The structural diversity and unique physicochemical properties of sulphated polysaccharides of red algae carrageenans (CRGs), to a great extent, determine the wide range of their antiviral properties. This work aimed to compare the antiviral activities of different structural types of CRGs: against herpes simplex virus type 1 (HSV-1) and enterovirus (ECHO-1). We found that CRGs significantly increased the resistance of Vero cells to virus infection (preventive effect), directly affected virus particles (virucidal effect), inhibited the attachment and penetration of virus to cells, and were more effective against HSV-1. CRG1 showed the highest virucidal effect on HSV-1 particles with a selective index (SI) of 100. CRG2 exhibited the highest antiviral activity by inhibiting HSV-1 and ECHO-1 plaque formation, with a SI of 110 and 59, respectively, when it was added before virus infection. CRG2 also significantly reduced the attachment of HSV-1 and ECHO-1 to cells compared to other CRGs. It was shown by molecular docking that tetrasaccharides—CRGs are able to bind with the HSV-1 surface glycoprotein, gD, to prevent virus–cell interactions. The revealed differences in the effect of CRGs on different stages of the lifecycle of the viruses are apparently related to the structural features of the investigated compounds. 相似文献
992.
[目的]探讨高湿胁迫下热带和温带玉米种质在植株形态和生理水平上的应答差异,为玉米耐湿种质的筛选及耐湿品种的培育提供理论依据.[方法]以10份来自热带和温带玉米种质的自交系为材料,采用随机区组设计,以田间正常生长的玉米自交系为对照(CK),在人工气候室进行高湿胁迫处理,胁迫处理10 d后取样测定不同处理玉米自交系的形态指标、生理指标及叶绿素荧光参数.[结果]高湿胁迫下,玉米自交系的株高、可见叶数、总叶面积、茎粗、植株鲜重和根体积均有不同程度的降低,耐湿指数范围分别为0.49~0.99、0.65~1.00、0.56~0.98、0.54~0.96、0.58~0.97和0.60~0.96.叶绿素、可溶性糖和可溶性蛋白质含量较CK也有所降低,其中,叶绿素、可溶性糖和可溶性蛋白质含量的耐湿指数均以自交系SC-3的最大,分别为0.95、0.90和0.95;以自交系TY-36的最小,分别为0.52、0.62和0.72.过氧化物酶(POD)活性、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量呈上升趋势,其中POD和SOD活性的耐湿指数以自交系TY-11的最大,分别为1.67和1.73;MDA含量的耐湿指数以TY-36的最大,为1.71;POD活性、SOD活性和MDA含量的耐湿指数均以自交系SC-3的最小,分别为1.03、1.04和1.03.高湿胁迫下玉米自交系的PSII潜在活性(Fv/Fo)、PSII最大光化学量子产量(Fv/Fm)、PSII有效光化学量子产量(ΦPSII)和光化学荧光淬灭系数(QP)均较CK有所下降.[结论]不同种质来源的玉米自交系对高湿胁迫存在形态生理应答差异,热带玉米种质的耐湿性高于温带玉米种质,可在热带种质中筛选耐湿玉米种质,培育耐湿玉米品种. 相似文献
993.
David M. Jaramillo José C. B. Dubeux Jr Joao M. B. Vendramini Luana M. D. Queiroz Erick R. S. Santos Martin Ruiz-Moreno Liza Garcia Daciele Sousa de Abreu Lucas Ramos de Miranda Michelle Cristina Fernando de Siqueira 《Grass and Forage Science》2020,75(2):153-158
Nitrogen fertilization is a common practice for sustaining forage production in forage systems in southeastern United States. Warm-season annual legumes may be an alternative forage to warm-season perennial grasses that do not require N fertilization. Sunn hemp (Crotalaria juncea L.) is a fast-growing, warm-season annual legume native to India and Pakistan. The objective of this 2-year study was to assess the herbage accumulation (HA), atmospheric N2 fixation (ANF) and nutritive value of sunn hemp. Treatments were the factorial arrangement of two sunn hemp cultivars (“Crescent Sun” and “Blue Leaf”), three seeding rates (17, 28 and 39 kg seed/ha) and seed inoculation (inoculated or non-inoculated seeds), distributed in a randomized complete block design with four replicates. Crescent sun had greater HA (3,218 vs. 1764 kg DM/ha) and ANF (41 vs. 25 kg N/ha). Blue leaf had greater crude protein (CP) (188 vs. 176 g/kg) and in vitro digestible organic matter (IVDOM) concentrations (564 vs. 531 g/kg) than crescent sun. Non-inoculated seed had greater CP than inoculated seed, 188 and 177 g/kg, respectively, and inoculation did not affect HA. Intermediate seeding rate (28 kg/ha) decreased HA (2002 kg DM/ha), while HA from high and low seeding rates (17 and 39 kg/ha, respectively) did not differ (2,863 and 2,615 kg DM/ha respectively). Planting non-inoculated crescent sun at 17 kg/ha seeding rate is a feasible management practice to produce sunn hemp in subtropical regions; however, inoculation should always be recommended for proper establishment. 相似文献
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Robson B de LIMA 《干旱区科学》2020,12(6):1046-1055
The volumetric variability of dry tropical forests in Brazil and the scarcity of studies on the subject show the need for the development of techniques that make it possible to obtain adequate and accurate wood volume estimates. In this study, we analyzed a database of thinning trees from a forest management plan in the Contendas de Sincorá National Forest, southwestern Bahia State, Brazil. The data set included a total of 300 trees with a trunk diameter ranging from 5 to 52 cm. Adjustments, validation and statistical selection of four volumetric models were performed. Due to the difference in height values for the same diameter and the low correlation between both variables, we do not suggest models which only use the diameter at breast height (DBH) variable as a predictor because they accommodate the largest estimation errors. In comparing the best single entry model (Hohenald-Krenn) with the Spurr model (best fit model), it is noted that the exclusion of height as a predictor causes the values of 136.44 and 0.93 for Akaike information criterion (AIC) and adjusted determination coefficient (R2 adj), which are poorer than the second best model (Schumacher-Hall). Regarding the minimum sample size, errors in estimation (root mean square error (RMSE) and bias) of the best model decrease as the sample size increases, especially when a larger number of trees with DBH≥15.0 cm are randomly sampled. Stratified sampling by diameter class produces smaller volume prediction errors than random sampling, especially when considering all trees. In summary, the Spurr and Schumacher-Hall models perform better. These models suggest that the total variance explained in the estimates is not less than 95%, producing reliable forecasts of the total volume with shell. Our estimates indicate that the bias around the average is not greater than 7%. Our results support the decision to use regression methods to build models and estimate their parameters, seeking stratification strategies in diameter classes for the sample trees. Volume estimates with valid confidence intervals can be obtained using the Spurr model for the studied dry forest. Stratified sampling of the data set for model adjustment and selection is necessary, since we find significant results with mean error square root values and bias of up to 70% of the total database. 相似文献