Aeromonas salmonicida infects Atlantic salmon (Salmo salar) erythrocytes

Aeromonas salmonicida subsp. salmonicida (hereafter A. salmonicida) is the aetiological agent of furunculosis in marine and freshwater fish. Once A. salmonicida invade the fish host through skin, gut or gills, it spreads and colonizes the head kidney, liver, spleen and brain. A. salmonicida infects leucocytes and exhibits an extracellular phase in the blood of the host; however, it is unknown whether A. salmonicida have an intraerythrocytic phase. Here, we evaluate whether A. salmonicida infects Atlantic salmon (Salmo salar) erythrocytes in vitro and in vivo. A. salmonicida did not kill primary S. salar erythrocytes, even in the presence of high bacterial loads, but A. salmonicida invaded the S. salar erythrocytes in the absence of evident haemolysis. Naïve Atlantic salmon smolts intraperitoneally infected with A. salmonicida showed bacteraemia 5 days post‐infection and the presence of intraerythrocytic A. salmonicida. Our results reveal a novel intraerythrocytic phase during A. salmonicida infection.     

ZF850型全液压自走式生物有机制肥设备

该设备是山东省农业机械科学研究所在充吸收国外先进技术的基础上自行开发设计的型绿色农业制肥设备。生化技术制造有机肥是当前处理秸秆的最途径,利用现代化设备和手段控制生产过程,秸秆或畜禽粪便制造成优质生物有机肥,其原是:用高新技术进行菌种的培养和生产,将粉的秸秆或其它农业废弃物与畜禽粪便按一定例混合后,经机械翻抛、高温堆腐、生物发酵等程,转换成优质有机肥。该设备配置82kW四缸涡轮增压式柴油机,功大、油耗低,行走和工作系统采用世界先进的闭式液压传动,匹配动力强劲,操纵灵活方便,其行走速度和整机高度无级可调,并具有完备…     

喷洒作业下四旋翼植保无人机的轨迹跟踪控制

针对所搭载药箱内药液变化导致四旋翼植保无人机喷洒作业品质下降的问题,为实现喷洒作业下四旋翼植保无人机的轨迹跟踪控制,提出一种喷洒作业下四旋翼植保无人机的轨迹跟踪控制方法.在考虑喷洒作业下药液变化影响的前提下,建立了四旋翼植保无人机的非线性动力学模型.在原有PD控制的基础上,引入模糊控制器对控制参数进行在线自适应整定,从...     

Mining of favorable marker alleles for flag leaf inclination in some rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) accessions by association mapping

Flag leaf angle (FLA) in rice (Oryza sativa L.) is one of the important traits affecting F₁ seed production by mechanization. To elucidate the genetic mechanism of FLA and mine favorable marker alleles for F₁ seed production in rice, we performed a genome-wide association study using phenotypic data over 2 years and genotypic data of 262 pairs of simple sequence repeat (SSR) markers collected from 441 rice accessions. We detected seven SSR marker loci associated with FLA and four loci were novel. The four newly found loci were RM6266 on chromosome 3, RM348 on chromosome 4, RM258 on chromosome 10 and RM7303 on chromosome 11. We found a total of 27 favorable alleles, of which four, i.e., RM348-130 bp, RM7303-90 bp, RM258-180 bp, and RM4835-230 bp, had phenotypic effects larger than 10°. Nine combinations, which increased FLA by 45.7°–94.7° through pyramiding the favorable alleles contained in seven typical accessions, were predicted.     

Aboveground biomass increment and stand dynamics in tropical evergreen broadleaved forest

Forest ecosystems can modify the atmospheric CO₂ through biomass accumulation mostly in tree stems with diameter at breast height (DBH) ≥ 10 cm. Aboveground biomass increment (ΔAGB), and changes in stand AGB, no. stems and basal area (BA) were calculated from mortality, recruitment, and growth data of tree stems in tropical evergreen broadleaved forest, Central Highland Vietnam. Data were derived from ten 1-ha permanent plots established in 2004, where all stems with DBH ≥ 10 cm were tagged, identified to species, and measured for DBH in 2004 and 2012. In an 8-year duration, the increment was 53 ± 10 stems ha^–1, 7.8 ± 0.3 m² ha^–1 for BA and 86.0 ± 4.6 Mg ha^–1 for AGB. The stem mortality rate was 0.9% year^–1 and the stem recruitment rate was 2.2% year^–1. Annual ΔAGB was 10.8 Mg ha^–1 year^–1, equaling to 5.4 Mg C ha^–1 year^–1. Of which, tree stems of 35–80 cm DBH classes accounted for 65%. The results indicated that the forest is in stage of carbon sequestration. Any disturbances causing death of 35–80 cm DBH tree stems will much reduce carbon sequestration capacity and it will take a long time for AGB to return to pre-disturbance stage.     

利用微生物防除根寄生杂草列当

根寄生杂草列当(Orobanche spp.)已经严重制约全球许多地区的农业发展,寻找有效防除措施迫在眉睫。由于列当具有特殊生活史且与寄主关系密切,常规防除杂草措施难以达到理想防效。目前,尚无既能有效防除列当又不对寄主造成危害且便于大规模推广应用的列当防除措施。在众多列当防除措施中,微生物防除越来越引起关注和重视。本文对微生物防除列当的国内外研究进展及防除机理进行了综述。目前,列当生防微生物的研究主要集中在镰刀菌(Fusarium spp.)等列当病原菌和根瘤菌(Rhizobium spp.)等列当寄主植物共生菌上。微生物防除列当的机制主要包括两方面:一是通过产生代谢产物直接影响列当的萌发和生长,或通过降解列当种子萌发诱导物质间接影响列当的萌发;二是通过提高寄主植物自身对列当的抗性间接影响列当的寄生和生长。此外,本文还重点介绍了植物土传病害的土壤拮抗微生物防除列当杂草的可行性及研究进展。植物土传病害病原菌和列当均首先通过在地下侵染作物的根系进而危害作物正常生长,而作物抗土传病害的机理也与抗列当的机理类似。因此,存在于土壤中具有防治植物土传病害能力的微生物可能也具有防除根寄生杂草列当的功能。本团队前期试验从植物土传病害的土壤拮抗微生物中筛选到在盆栽试验中能够有效防除向日葵列当(O.cumana Wallr.)和瓜列当(O.aegyptiaca Pers.)的放线菌各1株,分别为淡紫褐链霉菌(Streptomyces enissocaesilis Sveshnikova)和密旋链霉菌(Streptomyces pactum Bhuyan B.K)。其中,密旋链霉菌的菌剂在田间试验中既降低了瓜列当的出土数量又增加了番茄的产量。总之,微生物是防除根寄生杂草列当的一条有效途径。     

The potential of informal institutions for marine fisheries management—A case study of a coastal commune in Vietnam

The potential of informal institutions for sustainable management of marine fisheries was examined. The study is based on both primary data collected through two group discussions and interviews and secondary information, including material related to fishing gear operation and whale worship. It shows that informal institutions, including fisher groups, fishing community norms, fisher's knowledge and whale worship have potential to strengthen institutional, ecological, social and community aspects of sustainable fisheries development. Although these informal institutions are not able to fix completely all the problems faced by formal institutions, they are able to complement and consolidate formal institutions to manage marine fisheries effectively. The findings of this study suggest it is imperative that formal institutions should be improved simultaneously with informal institutions to enhance current management for sustainable marine fisheries development.