无机营养N,P,Ca和K对黑斑病菌侵染甘蓝幼苗的影响

将甘蓝幼苗分别培养在缺N(oN)、缺P(oP)、缺Ca(oCa)或缺K(oK)的不完全营养液中,培养56 d后分别于离体(Seg)和非离体(Int)叶片上接种黑斑病菌,以N,P,Ca和K营养素齐全的全营养液为对照,通过调查不同营养液处理后甘蓝叶片黑斑病的病斑大小,探讨N,P,Ca和K等无机营养素对黑斑病菌侵染甘蓝幼苗的影响。试验分2部分完成:第1部分缺N,缺P和缺Ca 3个处理同时进行,试验结果表明,不同营养液培养的甘蓝叶片黑斑病病斑大小有显著差异,顺序为对照>缺P>缺Ca>缺N处理;而在对照、缺P和缺Ca处理中,同一处理的非离体叶片病斑明显大于离体叶片病斑,缺N处理情况则相反。第2部分缺K处理的试验中,接种后5 d的病斑明显小于对照,非离体叶片与离体叶片接种后的病斑分别比对照小53%和14%;而缺K处理的离体叶片病斑显著比非离体叶片大(37%),并且病情随着接种后时间的延长而加重,在接种22 d后植株叶片和离体叶片的病斑大小趋于平衡。相关性分析表明,接种后5 d甘蓝幼苗活体组织和衰老组织的症状表达没有明显的相关性,但从试验2接种后22 d以及整个试验所有数据的结果分析,两者之间存在一定的相关性,相关系数达r=0.61。     

氨基酸添加方式和营养液杀菌方式对生菜产量与品质的影响

研究了生菜水培过程中,用混合氨基酸替代20％硝态氮时,不同的氨基酸添加方式和营养液的杀菌方式对生菜产量和品质的影响。试验于生菜采收前12 d开始进行,试验设置4个处理:A．替代氨基酸1次全部加入;B．每3 d添加氨基酸替代总量的1／4,共添加4次;C．氨基酸分次添加(添加方式同B处理),每次添加前营养液通臭氧0．5 h杀菌; D．氨基酸分次添加(添加方式同B处理),每次添加前把营养液加热到60-70℃保持10 min进行杀菌,然后迅速把营养液温度降低到常温。结果表明,在不杀菌的情况下,1次添加的产量和品质优于分次添加,但在降低硝酸盐含量方面,分次添加优于1次添加;在分次添加的情况下,杀菌与不杀菌相比,杀菌可以明显提高生菜的产量和品质,加热杀菌对生菜产量和品质的影响优于臭氧杀菌,臭氧杀菌处理的生菜根系活力、叶绿素等指标高于加热杀菌,但2种杀菌方式之间差异不大。     

Novel Alkaloids from Marine Actinobacteria: Discovery and Characterization

The marine environment is an excellent resource for natural products with therapeutic potential. Its microbial inhabitants, often associated with other marine organisms, are specialized in the synthesis of bioactive secondary metabolites. Similar to their terrestrial counterparts, marine Actinobacteria are a prevalent source of these natural products. Here, we discuss 77 newly discovered alkaloids produced by such marine Actinobacteria between 2017 and mid-2021, as well as the strategies employed in their elucidation. While 12 different classes of alkaloids were unraveled, indoles, diketopiperazines, glutarimides, indolizidines, and pyrroles were most dominant. Discoveries were mainly based on experimental approaches where microbial extracts were analyzed in relation to novel compounds. Although such experimental procedures have proven useful in the past, the methodologies need adaptations to limit the chance of compound rediscovery. On the other hand, genome mining provides a different angle for natural product discovery. While the technology is still relatively young compared to experimental screening, significant improvement has been made in recent years. Together with synthetic biology tools, both genome mining and extract screening provide excellent opportunities for continued drug discovery from marine Actinobacteria.     

Metal contamination from open-cast copper and sulphur mining in southeast Ireland

The metal content was determined in soil and vegetation around the eastern zone of the disused sulphur and copper mines at Avoca (southeast Ireland). A 250 m × 250 m grid survey was conducted covering a total area of 4 km². The mining belt was in the centre of the investigated site and was sampled separately. Iron, Zn, Cu and Cd concentrations in soil and plant material were determined, in addition to soil organic matter content and soil pH. Soil samples taken from the spoil showed elevated Cu and Cd concentrations, and low soil pH and organic matter content. At least 50 per cent of the agricultural sites examined around the East Avoca Mine showed elevated soil Cu and Cd concentrations, whereas Zn and Fe soil concentrations were within the range for unpolluted soils. None of the vegetation analysed had elevated Zn, Cd, Fe or Cu concentrations. Overall there was no indication of serious metal contamination in either soils or vegetation surrounding the mine in spite of extensive dust deposition during open-pit mining activity 15–30 years ago. However, a plume of elevated Cu in the soil was identified, which originated from a large spoil heap and had been spread for some 2·0 km by the prevailing wind.     

树木提取液抑制白蚁的效能试验

通过26种树木的不同提取液室内制剂筛选试验,从中筛选出灭蚁活性较强的树木提取液,分别配制9种单剂,在小型试验基础上优选配方,结合植物资源等因素,研制成环保型灭白蚁粉剂。用该粉剂在厦门、福州的公园中进行防治树木白蚁的药效试验,结果表明:处理后10 d的防效为76%~100%,处理后20 d的防效为81%~100%,处理后30 d的防效为100%,并且施药9个月后检查仍能持效。     

Long-term consequences of topsoil mining on select biological and physical characteristics of two New Zealand loessial soils under grazed pasture

Soil chemical, biochemical, biological and structural properties were measured in two New Zealand loessial soils that were topsoil-mined 10 and 25 years ago respectively. Measurements at the 10-year site were compared to some earlier measurements made at this site and the data combined in a chronological sequence for analysis. Topsoil mining had a large, detrimental impact on the soil microbial biomass, the earthworm populations, easily mineralizable N and soil enzyme activities. However, most of these properties substantially recovered, to 80-90 per cent of the levels in unmined soils, within 10-25 years of restoration under pasture. In contrast, while total soil C and N were less affected by topsoil mining, their recovery was much slower. Stabilities of macro-aggregates of soil had fully recovered within 10-25 years after topsoil mining. The apparent changes in all the measured properties between 10 and 25 years of restoration were small in comparison with changes between 0-10 years of restoration after topsoil mining. The total C content of both soils under pasture appeared unlikely to attain the levels present in unmined soils. In soils undergoing restoration, the ratio of microbial C/total soil C may be a useful index of soil ‘biological stability’. Sulphatase activity may reflect the recovery of pasture production.     

三类病毒感染下的手足口病模型的动力学分析

建立了CA16病毒、 EV71病毒及其他病毒株感染下周期性发病的手足口病模型.得到了模型的基本再生数并用它证明了模型无病平衡点的全局渐近稳定性.另外,分析了单一病毒株周期解的稳定性.最后,发现基本再生数最大的病毒株会持续生存下来,其他两种病毒株会被竞争排斥掉.     

罗汉果花提取液对亚硝酸盐清除效果研究

探索罗汉果花提取液对亚硝酸盐的清除效果,为罗汉果花的开发利用提供相关理论依据。以罗汉果花提取液对亚硝酸盐的清除率为考察指标,分别研究不同提取方法和提取溶剂所获得的提取液对亚硝酸盐的清除效果,在确定最佳提取方法和提取溶剂的基础上,通过单因素试验和正交试验对提取工艺进行优化。结果表明,采用蒸馏水作为溶剂,利用微波辅助浸提法效果较好,最佳提取工艺为：微波功率490 W,提取时间2 min,料液比1∶15（g/mL）。在此条件下,罗汉果花提取液对亚硝酸盐清除率达到56.83%。     

杨庄煤矿区农田塌陷水域多介质OCPs污染特征及生态风险研究

为研究采煤活动影响下农田塌陷水域有机氯农药(OCPs)的污染特征及潜在生态风险,使用GC-MS对淮南潘一矿的杨庄农田塌陷区水体和底泥中的OCPs特征污染物六六六(HCHs)及滴滴涕(DDTs)进行质量浓度测定,利用ArcGIS进行OCPs分布特征及来源研究,并选择共识沉积物质量基准法(CB-SQGs)对潜在生态风险进行分析。结果表明:杨庄沉陷区溶解态ΣOCPs质量浓度范围为72.06～218.89 ng·L~(-1),均值为167.32 ng·L~(-1);悬浮态和沉积态ΣOCPs范围为199.35～405.04 ng·g~(-1)dw和24.34～1 247.32ng·g~(-1)dw,均值为277.07 ng·g~(-1)dw和238.78 ng·g~(-1)dw;悬浮态和沉积态OCPs质量浓度自上游向下游方向随水流呈削减趋势;杨庄塌陷水体中HCHs主要来自于林丹,DDTs主要来自于农业三氯杀螨醇;溶解态OCPs低于国家Ⅲ类水质标准限额,处于低生态风险水平;悬浮态和沉积态OCPs处于中高生态风险水平,其中沉积态OCPs毒性发生率略低于悬浮态OCPs毒性发生率。     

南方某矿区土壤镉污染及作物健康风险研究

为了评估南方某县土壤镉污染情况、量化当地不同作物镉含量并对不同人群健康风险进行评估,从该县3个镇采集135份土壤样本,入户采集128份自产大米样本,种植区采集7份脐橙样本,对其中镉含量进行测定。结果表明,3镇采集土壤样品镉超标率分别为41.67%、28.81%和21.62%,地累积指数计算得到该县68.9%的土壤样本受到不同程度的镉污染,大米镉含量超标率分别为48.57%、34.48%、8.82%。而脐橙果肉样品中镉含量较低,远低于0.05 mg·kg^-1。计算不同作物的危害商数（HQ）可得,食用自产大米的危害商数（HQ）值普遍大于1,风险较高,而食用脐橙果肉产生的健康风险低。种植脐橙具有一定的经济效益,且当地具有脐橙适宜的生长条件,故考虑在重污染区种植脐橙取代种植水稻。