基于高分辨率卫星图像的株洲市绿地景观结构特征分析

城市绿地系统是城市生态系统的重要组成部分,对改善城市生态环境质量、提高人居生活水平、创造生态宜居型城市起着十分重要的作用(刘滨谊等,2002).为在有限的空间内合理规划布局城市绿地系统,需要在景观水平上研究城市绿地系统的结构特征,遥感和地理信息系统技术为该领域提供了有力的技术支持(肖笃宁等,2004).     

培养料C／N和含N量对毛木耳生长发育的影响

试验结果表明,商业化栽培毛木耳的培养料不需添加有机氮源,采用高C/N(60～100:1)和低含N量(0.4％～0.8％)的配方,干耳生物学效率(ABE％)为20％～24％,出耳后污染少,耳片商品率高。干耳产量(y_1=ABE％)、单袋经济效益(y_2,元/袋)、培养料C/N(x_1)及N％(x_2)的回归方程分别为: y_1=-15.1746 20.4322 lgx_1,r=0.9630,P>0.01; y_2=-3.5729 2.8329 lgx_1,r=0.9815,P>0.01; y_1=20.9942-20.7741 lgx_2,r=-0.9474,P>0.01; y_2=1.4202-2.4361 lgx_2,r=-0.8061,P>0.05。     

Inhibitory activities of semicarbazide-sensitive amine oxidase and angiotensin converting enzyme of pectin hydroxamic acid

Solutions of 100 mL of 1% commercial pectin each with a different degree of esterification (DE), DE94, DE65, and DE25, were reacted with 100 mL of 2 M alkaline hydroxylamine (pH 12.0) at room temperature for 4 or 18 h. These pectin hydroxamic acids (PHAs; DE94T4, DE94T18, DE65T4, and DE25T4) were used to test the inhibitory activities against semicarbazide-sensitive amine oxidase (SSAO) and angiotensin-converting enzyme (ACE). Compared to different DE pectins (DE94, DE65, and DE25), the PHAs of DE94T4, DE94T18, DE65T4, and DE25T4 showed different inhibition activities against SSAO or ACE. Commercial pectins with different DE values showed negligible SSAO or ACE inhibitions. The order of SSAO inhibition was DE65T4 > DE94T18 approximately DE25T4 > DE94T4. However, the order of ACE inhibition was DE94T4 > DE94T18 > DE65T4 > DE25T4. The SSAO activity staining or ACE-hydrolyzed products on TLC chromatogram also confirmed the inhibitory activities of PHAs against SSAO or ACE.     

SNP检测方法的研究进展

作为近年来最有发展潜力的第三代分子标记,单核苷酸多态性(single nucleotide polymorphism,SNP)在遗传分析中得到了广泛应用。目前SNP的检测方法大致可以分为两大类:一大类是以单链构象多态性(SSCP)、变性梯度凝胶电泳(DDGE)、酶切扩增多态性序列(CAPS)、等位基因特异性PCR(allele-specific PCR,AS-PCR)等为代表的以凝胶电泳为基础的传统经典的检测方法。另一大类是以直接测序、DNA芯片、变性高效液相色谱(DHPLC)、质谱检测技术、高分辨率溶解曲线(HRM)等为代表的高通量、自动化程度较高的检测方法。本文综述了两大类SNP检测方法中主要检测技术的原理和应用,并分析在实际应用中各种检测技术的优缺点。     

基于X-ray μCT技术的玉米籽粒结构特征的粒位效应分析

玉米籽粒因其在果穗上着生位置不同存在较大差异,明确籽粒结构特征的粒位效应为玉米的消费、加工和播种质量等玉米产量和品质性状的评价提供参考。该研究以3个不同籽粒类型的玉米品种登海618（DH618）、KX3564和先玉335（XY335）为材料,利用X射线计算机断层（X-ray micro-computed tomography,X-ray μCT）技术扫描测试样本,通过图像滤波、阈值分割等图像分析方法重建籽粒3维结构,获取玉米果穗不同粒位籽粒的胚、胚乳、皮下空腔、胚空腔、硬质胚乳、粉质胚乳、胚乳空腔等结构参数。数据分析表明,籽粒不同结构指标在果穗上呈现不同的变化规律,从基部到顶部（不考虑果穗两端的极端籽粒）,胚、胚乳及硬质胚乳体积线性下降,各指标在果穗上的变化范围分别为15.82～33.36、180.15～296.50及87.13～166.00 mm3;胚乳空腔>皮下空腔>胚空腔,果穗中部籽粒的空腔较小且稳定,3个品种表现一致;胚与胚乳的比值在粒位间基本稳定,粉质胚乳体积、硬质胚乳与粉质胚乳的比值从基部至顶部逐渐减小,但不同指标的变化斜率存在差异。3个供试品种的籽粒结构参数不同：DH618果穗不同部位籽粒胚与胚乳的比值大于KX3564和XY335,XY335籽粒硬质胚乳与粉质胚乳的比值大于DH618和KX3564。在籽粒空腔方面,KX3564皮下空腔的比例较高,而XY335胚乳空腔的比例较高。3个品种胚、胚乳、皮下空腔体积在玉米籽粒中的比例平均分别为9.27%、89.87%、0.86%。X-ray μCT扫描技术为玉米籽粒性状的研究提供新的方法与思路,明确果穗籽粒结构的粒位效应有利于全面地掌握玉米果穗上籽粒的性状特征,为玉米的生产、加工及品种改良等提供借鉴。     

Methionine deficiency and its hydroxy analogue influence chicken intestinal 3-dimensional organoid development

Methionine and its hydroxy analogue(MHA)have been shown to benefit mouse intestinal regeneration.The intestinal organoid is a good model that directly reflects the impact of certain nutrients or chemicals on intestinal development.Here,we aimed to establish a chicken intestinal organoid culture method first and then use the model to explore the influence of methionine deficiency and MHA on intestinal organoid development.The results showed that 125-mm cell strainer exhibited the highest efficiency for chicken embryo crypt harvesting.We found that transforming growth factor-b inhibitor(A8301)supplementation promoted enterocyte differentiation at the expense of the proliferation of intestinal stem cells(ISC).The mitogen-activated protein kinase p38 inhibitor(SB202190)promoted intestinal organoid formation and enterocyte differentiation but suppressed the differentiation of enteroendocrine cells,goblet cells and Paneth cells.However,the suppression of enteroendocrine cell and Paneth cell differentiation by SB202190 was alleviated at the presence of A8301.The glycogen synthase kinase 3 inhibitor(CHIR99021),valproic acid(VPA)alone and their combination promoted chicken intestinal organoid formation and enterocyte differentiation at the expense of the expression of Paneth cells and goblet cells.Chicken serum significantly improved organoid formation,especially in the presence of A8301,SB202190,CHIR99021,and VPA,but inhibited the differentiation of Paneth cells and enteroendocrine cells.Chicken serum at a concentration of 0.25%meets the requirement of chicken intestinal organoid development,and the beneficial effect of chicken serum on chicken intestinal organoid culture could not be replaced by fetal bovine serum and insulin-like growth factor-1.Moreover,commercial mouse organoid culture medium supplemented with A8301,SB202190,CHIR99021,VPA,and chicken serum promotes chicken organoid budding.Based on the chicken intestinal organoid model,we found that methionine deficiency mimicked by cycloleucine suppressed organoid formation and organoid size,and this effect was reinforced with increased cycloleucine concentrations.Methionine hydroxy analogue promoted regeneration of ISC but decreased cell differentiation compared with the results obtained with L-methionine.In conclusion,our results provide a potentially excellent guideline for chicken intestinal organoid culture and insights into methionine function in crypt development.     

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.     

Acanthopanax senticosus extract as a dietary additive enhances the apparent ileal digestibility of amino acids in weaned piglets

The present study was conducted to determine the effects of Acanthopanax senticosus (AS) extract as a dietary additive on serum contents and apparent ileal digestibility (AID) of amino acids (AA) in weaned piglets. In Exp. 1, 60 piglets with an average body weight (BW) of 5.64 kg were randomly assigned into 3 treatment groups who received maize-soybean-based diets supplemented with 0 or 1 g/kg of AS extract or 0.2 g/kg of colistin (n = 20 in each group). Blood samples were randomly collected from 5 piglets per group on days 7, 14 and 28 after the initiation of supplementation to determine the serum contents of free AA. In Exp. 2, 12 barrows with an average initial BW of 7.64 kg were also randomly assigned into 3 dietary treatment groups after being surgically fitted with a simple T-cannula at the terminal ileum. Samples of terminal ileal digesta were collected on day 7 for analysis of the AID of AA. The data showed that the serum contents and AID of most AA in the AS extract-supplemented group gradually increased by 15.3–80.8% and 4.1–30.8%, respectively, as the experiment proceeded in comparison with the colistin-supplemented group and/or control group. In conclusion, these findings indicated that AS extract could enhance the digestion and absorption of AA, which may be a potential mechanism of growth promotion.     

Plasmid containing CpG motifs enhances the efficacy of porcine reproductive and respiratory syndrome live attenuated vaccine

Porcine reproductive and respiratory syndrome (PRRS) is now among the most important swine diseases that affect the Chinese swine industry. Both killed and live attenuated vaccines are currently used against the disease, but neither of them could provide full protection after vaccination. In the present study, the adjuvanticity of a plasmid containing CpG motifs (pUC18-CpG) was introduced to enhance the efficacy of a commercial PRRS live attenuated vaccine. After vaccination, PRRSV-specific antibodies, PRRSV-specific cytokines, and clinical parameters were studied and compared between different vaccinated groups. During a following challenge study, co-administration of pUC18-CpG with the vaccine could confer higher protection rate. Our results have shown that co-administration of pUC18-CpG with the vaccine could elicit more potent adaptive immune response and provide better protection.     

河北省农业经济数据管理与服务平台建设

为了更好地为农业科学研究、管理决策服务,搭建了河北省农业经济数据管理与服务平台.通过该平台,可以实现河北省农业经济数据的自定义分区查询和汇总,多条件组合查询和汇总;查询结果可以打印、下载、图形分析与统计分析.具有界面友好、易扩展、易维护等特点.