Antimicrobial Compounds from Eukaryotic Microalgae against Human Pathogens and Diseases in Aquaculture

The search for novel compounds of marine origin has increased in the last decades for their application in various areas such as pharmaceutical, human or animal nutrition, cosmetics or bioenergy. In this context of blue technology development, microalgae are of particular interest due to their immense biodiversity and their relatively simple growth needs. In this review, we discuss about the promising use of microalgae and microalgal compounds as sources of natural antibiotics against human pathogens but also about their potential to limit microbial infections in aquaculture. An alternative to conventional antibiotics is needed as the microbial resistance to these drugs is increasing in humans and animals. Furthermore, using natural antibiotics for livestock could meet the consumer demand to avoid chemicals in food, would support a sustainable aquaculture and present the advantage of being environmentally friendly. Using natural and renewable microalgal compounds is still in its early days, but considering the important research development and rapid improvement in culture, extraction and purification processes, the valorization of microalgae will surely extend in the future.     

竹农参与技术创新过程中科技资源配置的帕累托效应

以解决竹业技术推广态势下造成的竹农和科研机构双方在时间、空间上的技术供需“断层”为出发点,提出竹农参与技术创新来改变科技资源在时间和空间上重新配置,认为从竹农角度看,这种重新配置是一种市场配置行为,而从科研机构角度看,却是一种半市场配置行为。在比较科研机构与竹农科技资源的优劣势的基础上,认为竹农参与技术创新不仅可以带来整个社会财富福利的增加,而且使竹农和科研机构双方的福利有所提升,从而使科技资源配置在假设前提下获得帕累托改进。     

Antioxidant Bioactivity of Extracts from Beach Cast Leaves of Posidonia oceanica (L.) Delile

The marine environment is a generous source of biologically active compounds useful for human health. In 50 years, about 25,000 bioactive marine compounds have been identified, with an increase of 5% per year. Peculiar feature of algae and plants is the production of secondary metabolites, such as polyphenols, synthesized as a form of adaptation to environmental stress. Posidonia oceanica is a Mediterranean endemic and dominant seagrass and represents a biologically, ecologically and geologically important marine ecosystem. Within this study, methanolic and ethanolic extracts were generated from fresh and dried Posidonia oceanica leaves, with the aim to employ and valorize the beach cast leaves. The best yield and antioxidant activity (polyphenols content equal to 19.712 ± 0.496 mg GAE/g and DPPH IC50 of 0.090 µg/µL.) were recorded in 70% ethanol extracts (Gd-E4) obtained from leaves dried for two days at 60 °C and ground four times. HPLC analyses revealed the presence of polyphenols compounds (the most abundant of which was chicoric acid) with antioxidant and beneficial properties. Bioactive properties of the Gd-E4 extracts were evaluated in vitro using fibroblast cells line (HS-68), subjected to UV induced oxidative stress. Pre-treatment of cells with Gd-E4 extracts led to significant protection against oxidative stress and mortality associated with UV exposure, thus highlighting the beneficial properties of antioxidants compounds produced by these marine plants against photo damage, free radicals and associated negative cellular effects. Beach cast leaves selection, processing and extraction procedures, and the in vitro assay results suggested the potentiality of a sustainable approach for the biotechnological exploitation of this resource and could serve a model for other marine resources.     

Novel Wx alleles induced by chemical mutagens in rice,Oryza sativa L.

From mutant pools of two Taiwanese elite japonica cultivars, Tainung 67 and Taikeng 8, we identified 13 mutant lines possessing opaque endosperm with relatively low amylose contents (AC) ranging from 1.5% to 7.1%. Because of different AC, paste viscosities of these 13 mutant lines differed, as revealed by palatability and physicochemical properties. The mutated gene conferring opaque endosperm was isolated from the F₂ population of one mutant line, WY1× indica cv. ‘Taichung Sen 17’, by positional cloning, revealing a G3018→A3018 substitution at exon 9 of Waxy leading to a non‐synonymous mutation from alanine to valine. Two additional alleles were identified from the other 12 mutant lines, for which single‐nucleotide substitutions G2708 → A2708 and G3029 → A3029 occurred in exons 8 and 9, leading to non‐synonymous mutations from arginine to histidine and glutamic acid to lysine, respectively. The three novel wx alleles had different effects on grain quality, specifically on eating and cooking quality, and could be applied in rice breeding programmes to develop new low AC varieties by marker‐assisted selection.     

常熟市农业生态环境质量的可变模糊评价

对农业生态环境质量进行评价,是制定农业及社会可持续发展政策的依据。农业生态环境质量的评价属于模糊概念。采用可变模糊集模型进行评价,以级别特征值方法量化评价结果,可有效解决最大隶属原则的不适应性。本文运用该模型对江苏省常熟市农业生态环境质量进行了评价。对比文献[14],体现了该模型适用性,能更客观地评价该市农业生态环境质量状况。根据评价结果,该文对常熟市生态环境的维护提出了建议。     

Influence of mitochondria origin on fruit quality in a citrus cybrid

Sugar, organic acid, and carotenoid are the most important indicators of fruit taste and nutritional and organoleptic quality. These components were studied on fruit pulp of the cybrid between Willow leaf mandarin ( Citrus deliciosa Ten.) and Eureka lemon [ Citrus limon (L.) Burm.] and the two parents. The cybrid possessed nuclear and chloroplast genomes of Eureka lemon plus mitochondria from Willow leaf mandarin. The impact of new mitochondria on fruit quality was studied during the mature period. Levels of organic acids were slightly higher in the cybrid fruit pulp than in Eureka lemon. No significant difference in sugar and carotenoid content was observed between the cybrid and the lemon. Results confirm that the main genetic information for the biosynthesis of sugars, organic acids, and carotenoids is contained in the nucleus. In Citrus, cybridization can be used as a strategy to breed specific traits associated with mitochondrial genomes, such as male sterility, without affecting the main organoleptic and nutritional qualities.     

土耳其斯坦叶螨对杀螨剂的抗性选育及解毒酶活力变化

为探索土耳其斯坦叶螨的抗药性及其生化机理,在室内对敏感系土耳其斯坦叶螨分别用螺螨酯、甲氰菊酯和阿维菌素逐代处理,选育出抗性种群。结果表明,选育至15代,土耳其斯坦叶螨对螺螨酯、甲氰菊酯和阿维菌素的抗性指数分别达到268.63、37.98和112.68倍。分别测定敏感品系(SS)、抗螺螨酯(RS)、抗甲氰菊酯(RF)、抗阿维菌素(RA)品系的解毒酶活性显示,3种不同抗性品系相对SS品系的羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GSTs)和多功能氧化酶(MFO)的比活力均有不同程度的提高,差异均达到显著水平(P0.05)。其中,RF品系的MFO比活力上升最快,是SS品系的12.7倍;RA品系的MFO比活力次之,是SS品系的5.76倍;RS品系的3种解毒酶比活力均增长较慢,其中CarE比活力上升最慢,是SS品系的1.31倍。由此表明,CarE、GSTs、MFO的活性增大可促进土耳其斯坦叶螨对3种杀虫剂的抗性形成;螺螨酯的抗性增强可能与CarE关系甚微;MFO活性的增加可能与甲氰菊酯抗性升高密切相关;GSTs、MFO的活性升高可能是土耳其斯坦叶螨对阿维菌素产生抗性的主要原因。     

傅里叶变换红外光谱技术评估玉米器官含氮量的可行性研究

探究傅里叶红外光谱（FTIR）技术评估作物器官含氮量的可行性,对快速掌握作物氮素状况、优化氮肥管理具有重要意义。利用低分子量较少的腐植酸（HA1）和低分子量较多的腐植酸（HA2）开展玉米水培试验,通过设置不同的腐植酸浓度短期内获得了器官氮素含量差异较大的植物样品;在测定/采集玉米各器官含氮量与FTIR光谱数据的基础上,利用主成分分析方法探究了玉米各器官含氮量与FTIR特定波数吸光度的相关性,以明确可用于评价玉米样品含氮量的FTIR特征参数。结果显示：（1）不同浓度HA1与HA2对玉米各器官含氮量产生了差异化影响,表现为2.5 mg·L^-1 HA1显著提高了叶片、茎秆及根系的含氮量（P < 0.05）,含氮量较对照分别提高20.8%,19.9%以及64.2%,但各器官含氮量随HA1浓度的提高呈降低趋势,当HA1浓度达到25 mg·L^-1时,各器官含氮量均低于对照;HA2整体上提高了各器官的含氮量,其中显著提高了根系含氮量,提高幅度达到了35.0%～45.4%。（2）不同浓度HA1与HA2对玉米各器官在1 051.0、1 159.0、1 247.7、1 635.3、1 650.8、1 731.8以及2 919.7 cm^-1处FTIR吸光度的影响与含氮量相似,即各浓度HA2与低浓度HA1可提高玉米器官蛋白质、脂类、糖类等有机组分的含量。（3）主成分分析结果表明,与叶片含氮量高度相关的3个特征波数分别为1 635.3、1 247.7以及1 159.0 cm^-1;茎秆为1 650.8和1 159.0以及 1247.7 cm^-1;根系为1 635.3、1 650.8以及1 159.0 cm^-1,即比较玉米各器官上述波数处FTIR的吸光度可用于评估玉米样品的含氮量,吸光度越高,含氮量越高。通过比较玉米各器官FTIR特定波数处的吸光度可以初步评估不同农艺措施对玉米各器官含氮量的影响,这为将来FTIR在植物氮素营养诊断方面的应用提供了重要参考。     

Mapping ethnic groups in Lao Cai Province,Vietnam

This research note offers a brief summary of recent cartographic work in the province of Lao Cai in northern Vietnam, with a specific focus on the districts of Sa Pa and Bac Ha. By providing a representation of topography in digital format, which enables a connection between demographic and physical variables, the long term aim is to illustrate the relationship between ethnicity and topography.     

滴灌条件下枯草芽胞杆菌S37和S44对棉花黄萎病的防治效果

采用拌种和随水滴施2次的方法测定了2株芽胞杆菌对棉花黄萎病的防治效果。结果表明,在滴灌条件下2株枯草芽胞杆菌对棉花黄萎病均表现出较好的防治作用,在小区试验中,S37和S44对棉花黄萎病的防治效果分别为29.86%和42.81%,产量分别增加了25.22%和34.73%。在田间试验中,S37在143团和147团的防病效果分别为51.3%和55.1%,增产效果分别达到7.43%和17.62%,S44在143团和147团的防病效果分别为35.2%和39.3%,增产效果分别达到5.56%和15.51%。