Aging of colloidal contaminants and pathogens in the soil environment: Implications for nanoplastic and COVID-19 risk mitigation

Colloidal contaminants and pathogens are widely distributed in soil, whose tiny sizes and distinct surface properties render unique environmental behaviours. Because of aging, colloids can undergo dramatic changes in their physicochemical properties once in the soil environment, thus leading to diverse or even unpredictable environmental behaviour and fate. Herein, we provide a state-of-art review of colloid aging mechanisms and characteristics and implications for risk mitigation. First, we review aging-induced formation of colloidal contaminants and aging-associated changes. We place a special focus on emerging nanoplastic (NP) contaminants and associated physical, chemical, and biological aging processes in soil environments. Second, we assess aging and survival features of colloidal pathogens, especially viruses. Viruses in soils may survive from several days to months, or even several years in groundwater, depending on their rates of inactivation and the reversibility of attachment. Furthermore, we identify implications for risk mitigation based on aging mechanisms. Hotspots of (photo)chemical aging of NPs, including plastic gauzes at construction sites and randomly discarded plastic waste in rural areas, are identified as area requiring greater research attention. For COVID-19, we suggest taking greater care in regions where viruses are persist for long periods, such as cold climate regions. Soil amendment with quicklime (CaO) may act as an effective means for pathogen disinfection. Future risk mitigation of colloidal contaminants and pathogens relies on a better understanding of aging mechanisms and more sophisticated models accurately depicting processes in real soil environments.     

Applying molecular docking to pesticides

Pesticide creation is related to the development of sustainable agricultural and ecological safety, and molecular docking technology can effectively help in pesticide innovation. This paper introduces the basic theory behind molecular docking, pesticide databases, and docking software. It also summarizes the application of molecular docking in the pesticide field, including the virtual screening of lead compounds, detection of pesticides and their metabolites in the environment, reverse screening of pesticide targets, and the study of resistance mechanisms. Finally, problems with the use of molecular docking technology in pesticide creation are discussed, and prospects for the future use of molecular docking technology in new pesticide development are discussed. © 2023 Society of Chemical Industry.     

肉牛长途运输诱发应激综合征的诊治

为确诊引起新疆某基层团场长途调运西门塔尔后备母牛发病死亡的病因,通过临床剖解,结合常规细菌分离鉴定、PCR检测,对发病肉牛进行现场诊断和实验室检测确诊,证实引起此次西门塔尔肉牛发病死亡的主要原因是长途运输诱发的应激综合征,主要致病菌为巴氏杆菌和支原体,并伴有附红细胞体混合感染。针对病因和药敏试验结果,采取了抗菌消炎和对症治疗等措施,发病死亡情况由此得到有效控制。此病例的诊治为新疆地区长途调运牛只时,降低类似事件的发生提供了一定的理论基础和实践指导。     

草原补奖政策下牧户是否超载？谁在超载及影响因素——以内蒙古为例

本文以内蒙古自治区草甸草原、典型草原、荒漠草原、沙地草原、草原化荒漠草地的15个旗县791户牧户为调查样本,以可持续生计资本为视角,通过建立二元Logit模型和多元线性回归模型,分析第一轮草原生态补奖政策实施期结束后,牧民草场是否超载?超载牧户的特征是什么?超载的程度如何?调查结果表明：内蒙古自治区第一轮草原生态补奖政策实施结束后牧户草场超载率平均值为44.70%;牧户草场超载率与草场经营规模呈负向相关关系,其超载率由高到低依次为小牧户 > 中牧户 > 大牧户;牧户草场超载率与畜牧业生产依赖程度呈负向相关关系,其超载率由高到低依次为纯牧户 > 兼牧户 > 非牧户;草场经营面积、冬季牲畜和固定资产数量成为影响牧户草场超载行为的关键生计指标,牧户草场经营面积对其呈显著负向影响,冬季家畜和固定资产数量对其呈显著正向影响。综上,第一轮草原生态补奖政策实施结束后牧户草场超载现象依然存在,超载率与草场资源占有率呈负向关系,与其对草原的依赖程度呈正向关系。     

不同日照时长对玫瑰茄主要农艺性状的影响

以玫瑰茄MG1501-1和MG1502-2为试验材料,以自然光为对照（CK）,分别设置日照时长8.0、9.5和11.0h处理,探讨不同日照时长对玫瑰茄主要农艺性状的影响。结果表明,自然光照条件下,植株粗壮,叶片浓绿,长势好;日照11.0h处理,植株粗壮,叶片浓绿,花蕾正常且着色均匀;日照8.0h处理植株徒长,茎细长,叶片淡绿,变态花蕾多且着色不均匀,呈现红绿相间条纹,花蕾基部为橘红色;群体长势强弱依次为CK>11.0h>9.5h>8.0h处理;现蕾期、始花期以及成花逆转出现期早晚依次均为11.0、9.5、8.0h处理;植株株高依次为CK>8.0h>9.5h>11.0h处理,处理间差异不显著;光照11.0h处理分枝数、鲜果数最多;鲜果重、鲜萼片和干萼片产量最高,均显著高于其他处理。综合各项指标,日照时长11.0h处理主要产量性状优于8.0、9.5h以及CK处理,且成功诱导玫瑰茄开花结果,促使玫瑰茄于长日环境下开花结果,实现了玫瑰茄反季节栽培、增加了复种指数和经济效益。     

覆盖生态木屑对‘染井吉野’樱花根系分布特征的影响

树木的根系分布是影响灌溉效果的重要因素,为实现园林树木的科学灌溉,对‘染井吉野’樱花的根系分布特征和覆盖生态木屑对根系分布特征的影响开展研究。采用根钻法对玉渊潭公园内大面积种植的‘染井吉野’樱花根系进行定点逐层取样,利用Win-RHIZO Pro根系分析系统分析根的总长度、直径小于1 mm的根的总长度、根的投影面积、根的表面积和根尖计数等指标。结果表明：‘染井吉野’樱花的吸收根水平方向可以伸展长达6 m,垂直方向上则主要集中在0~20 cm的土层内;铺设生态木屑对土壤表层樱花根系具有明显的促进作用,铺设不同厚度生态木屑对樱花根系分布特征影响不同,覆盖5~10 cm厚生态木屑后樱花根系总长度达到(782.98±401.29) cm,是不铺生态木屑的樱花根系总长度的10倍,是其他试验组的2倍以上。樱花属于浅根系树种,城市公园环境使‘染井吉野’樱花根系主要分布于土壤表层,但分布范围甚广,能够达到树干投影面积的2倍;铺设生态木屑促使樱花根系向土壤表层集中,铺设5~10 cm厚的生态木屑可以有效促进土壤表层樱花根系生长,但对土壤深度20 cm以下的樱花根系影响较小。     

小菜蛾三类主要化感受体基因的虫态、组织和性别表达特异性分析

为明确小菜蛾Plutella xylostella体内主要化感受体的表达分布特性,通过对特定组织转录组数据分析并结合半定量RT-PCR测定,研究小菜蛾气味受体（odorant receptor,OR）、离子型受体（ionotropic receptor,IR）和味觉受体（gustatory receptor,GR）3类化感受体基因在不同虫态、组织及性别中的表达特异性。转录组数据分析结果显示,共有48个OR、8个IR和15个GR基因在被测组织中表达,不同基因呈现不同的组织表达特异性。通过整合基因组和转录组数据分析共获得62个GR基因,其中48个为全长序列;系统进化树分析结果表明,48个全长GR中3个属于CO₂受体,10个属于糖受体,35个属于苦味受体;成虫头（去除触角后）、触角、足、翅、雌成虫产卵器及4龄幼虫头部分别表达19、22、27、21、24和21个GR基因;成虫性别间比较发现,PxylGR2、PxylGR20、PxylGR61基因在雌成虫头部中表达量较高,PxylGR5、PxylGR23、PxylGR34、PxylGR37基因在雌成虫触角中表达量较高,PxylGR37、PxylGR53、PxylGR54基因在雌成虫足中表达量较高,而PxylGR17、PxylGR21和PxylGR22基因在雄性翅中表达量较高。     

不同磷肥用量及施用方式对土壤有效磷分布和冬小麦产量的影响

为了最大程度提高磷肥的增产潜力,实现冀中南施肥减量增效,通过田间试验和室内检测的方法,研究了以固体磷肥全部底施为对照,不同施磷处理对土壤有效磷分布和冬小麦产量及产量因素的影响。结果表明：（1）与习惯施磷肥方式相比,水肥一体化喷施液磷肥可使20~60 cm土层有效磷含量提高明显;（2）减少基施固体磷肥,改为春季水肥一体化喷施液态磷肥,可增加穗粒数和千粒重,提高冬小麦产量;（3）磷肥施用宜底施固体(P₂O₅) 90 kg/hm²的基础上,春季喷施液态(P₂O₅) 30 kg/hm²小麦产量效果为佳。底施固体磷肥,并在春季分2次平均水肥一体化追施液体磷肥,可实现磷肥施用“下移增效”。