Abstract:目的 明确广东地区鸭疫里默杆菌Riemerella anatipestifer的血清型、耐药状况及遗传进化关系。方法 从规模化鸭场分离鉴定鸭疫里默氏杆菌，通过玻片凝集试验鉴定血清型；利用试管两倍稀释法测试抗菌药物的最低抑菌浓度，分析药物的敏感性；采用全基因组测序技术分析序列特征并构建核心基因组遗传进化树。结果 共分离鉴定鸭疫里默氏杆菌168株，血清1、2、3、5、6、7、8、10型均有流行，血清1型的菌株高达54.17% (91/168)，其次为2型，占27.97%(47/168)。48株代表性菌株对庆大霉素、卡那霉素、盐酸环丙沙星表现高度耐药，耐药率均超过80%；对土霉素、盐酸四环素、盐酸金霉素、氧氟沙星、诺氟沙星、磺胺二甲嘧啶、磺胺对甲氧嘧啶的耐药率均在60%以上；对阿莫西林、头孢噻肟和大观霉素的耐药率低于30%。受试菌株对5~12种药物耐药，共有44种耐药谱型。成功获得46株菌株全基因组序列，共检出6种耐药基因，其中，耐药基因erm(F)和tet(X)的检出率较高，分别为73.91%(34/46)和82.60%(38/46)，同时携带2种以上耐药基因的菌株占95.65%(44/46)。18株(39.13%，18/46)菌株ST分型成功，分属11个ST型。所有测序菌株与数据库中来自中国的菌株在遗传进化关系上最接近，主要存在于优势克隆群系Clade 1和Clade 3中。结论 本研究鸭疫里默氏杆菌分离株的优势血清型为1型，耐药性严重，所携带的耐药基因与耐药表型具有一定相关性，ST型呈多样性，与多位点序列分型(Multi-locus sequence typing, MLST)数据库中来自我国菌株的遗传背景相近。研究结果可为鸭疫里默氏杆菌病疫苗免疫预防与药物治疗提供依据，有助于掌握鸭疫里默氏杆菌遗传进化特征。

Abstract:Objective To investigate the epidemic characteristics, drug resistance, multi-locus sequence typing (MLST) and genetic evolution background of Pseudomonas aeruginosa in Guangdong Province, and provide a reference for clinical rational drug use. Method Samples from dead embryos of pheasant and their surrounding environment were collected for separation and identification of P. aeruginosa. The K-B paper disk diffusion method was used to analyze P. aeruginosa sensitivity to 22 kinds of antimicrobials. The MLST method was applied to analyze the molecular epidemiology of P. aeruginosa strains. Seven house-keeping genes of each ST type were spliced sequentially, and we used MEGA7 software to conduct genetic evolution analysis to the spliced sequence. Result A total of 145 P. aeruginosa strains (isolation rate 28.2%) were isolated from the collected 514 samples (405 dead embryo samples and 109 environment samples), including 24 strains from environmental samples (isolation rate 22.0%, 24/109) and 121 strains from dead embryos (isolation rate 29.9%, 121/405). Antibiotic drug sensitivity test showed that 145 strains of P. aeruginosa were naturally resistant to ampicillin, kanamycin and nalidixic acid, strongly resistant to complex sulfamethoxazole, chloramphenicol, tetracycline, followed by cefotaxime, with the drug resistance rates of 100%, 80.0%, 77.2% and 23.4% respectively. Except the natural drug resistance, the proportion of multiple drug resistant P. aeruginosa was up to 73.1% (106/145), and a certain proportion of P. aeruginosa strains which were resistant to imipenem appeared. MLST analysis showed that 89 P. aeruginosa strains with a broad spectrum of resistance were divided into 18 ST types, presenting high diversity. Among them, six ST types were the new types discovered in this study. The dead embryo isolates of P. aeruginosa were mainly ST-260, and the environmental sample isolates were mainly ST-2100 and ST-3202. Genetic evolution analysis showed that P. aeruginosa strains in environment were closely related to those in dead embryos. Conclusion There are different degrees of P. aeruginosa infection or contamination in dead embryos and surrounding environment of three pheasant farms, and the isolates have strong drug resistance. Therefore, it is recommended that we should not only strengthen the breeding management and raise the awareness of bio-safety in the process of breeding, but also use antibacterial drugs reasonably according to the results of the drug sensitivity test.

Abstract:Objective A molecularly imprinted polymer adsorbent with specific recognition for mycophenolic acid was synthesized for purification, enrichment and analysis of mycophenolic acid in silage.Method Using silica gel modified by γ-methacryloxy propyl trimethoxy silane (γ-MPS) as the carrier, mycophenolate mofetil as the virtual template, the surface molecularly imprinted polymers were prepared on silica gel. The prepared materials were characterized by scanning electron microscopy, and the adsorption characteristics were evaluated by equilibrium adsorption test. The solid phase extraction-high performance liquid chromatography (HPLC) method based on the synthesized molecularly imprinted polymer was established to detect the mycophenolic acid in silage.Result The modified silica gel surface was successfully wrapped with a layer of molecularly imprinted polymer. The static adsorption test showed that the saturated adsorption capacity of the imprinted material was 4.5 mg/g, and the dynamic adsorption test showed that the adsorption rate of the material was fast, and the adsorption equilibrium was reached within 60 min. The HPLC method was established using the imprinted material as the solid phase extraction adsorbent. The recovery rates of mycopholanolic acid were in the range of 76.0% to 81.2%, the relative standard deviation was less than 7%, and the detection limit was 60 μg/kg.Conclusion The prepared mycophenolic acid molecularly imprinted polymer on the surface of silica gel can specifically adsorb mycophenolic acid. The established molecularly imprinted polymer solid phase extraction-HPLC method can be used for daily determination of mycophenolic acid in silage to know the situation of mycotoxin contamination in feed. The results can provide guidance for quality safety control of silage.

Abstract:Objective Compared with the wild type mice, the homozygous ETV5 knockout mice prepared by CRISPR/Cas9 technology showed significant weakness in body size and body weight along with endogenous spermatogonial stem cell ablation. The purpose of this study was to explore the effect of ETV5 knockout on the muscle expression profile of mice.Method The muscle tissues of three wild-type male mice and three ETV5 homozygous knockout male mice aged six weeks were collected and total RNA was extracted for transcriptome sequencing. We analyzed the sequencing results using bioinformatic method. Cluster analysis, GO and KEGG enrichment analyses were performed on the differentially expressed genes in the muscle samples of two groups of mice.Result A total of 574 differentially expressed genes were screened out from the muscle tissues of two groups, including 292 up-regulated genes and 282 down-regulated genes. Several genes were found to affect the growth and development of ETV5 knockout mice. These genes included Amd1 affecting muscle development of mice, and Chrna2 affecting fat accumulation. Most of the pathways enriched by GO and KEGG analyses were related to fat metabolism and growth and development.Conclusion These results provide an explanation for the molecular mechanism of abnormal development of ETV5 knockout mice, and provide references for further study of in vivo function of ETV5 gene.

Abstract:目的 研究高、低温诱导家蚕Bombyx mori滞育发生时蚕卵蛋白质修饰的差异，为后续深入探究昆虫滞育诱导的分子机制提供参考。方法 饲养二化性家蚕品种，筛选出稳定的受高、低温诱导滞育发生的家蚕品系。以此为材料，分别于25和15 ℃孵化蚕卵，敏感期和点青期取样进行表观遗传学研究，通过SDS-PAGE电泳和Western blot检测蛋白修饰的差异。结果 高温(25 ℃)组蚕卵蛋白的甲基化修饰水平始终高于低温(15 ℃)组，点青期有显著差异；高、低温处理组之间的乙酰化修饰水平一直差异显著，在点青期高温组显著低于低温组；低温组的泛素化修饰水平始终高于高温组，尤其是发育前期；磷酸化修饰水平整体较高，但高、低温处理组之间差异不显著；丙二酰化在高、低温处理组之间没有明显差异；琥珀酰化的修饰水平始终较低，在发育后期有明显的差异修饰蛋白出现。结论 蚕卵在25 ℃催青过程中蛋白质泛素化和乙酰化修饰水平与15 ℃低温组在全时期都存在显著差异，甲基化修饰水平在点青期存在显著差异，表明甲基化、泛素化和乙酰化修饰在家蚕早期滞育诱导过程中起作用。

Abstract:Object To explore the promoting action of photothermal conversion effect of submicron Prussian blue (smPB) on its photo-Fenton catalytic degradation of methylene blue (MB) pollutants.Method Using sodium ferrocyanide and polyethylenimine (PEI) as main materials, smPB with photothermal and photo-Fenton-catalytic degradation was prepared by hydrothermal slow crystallization method using amino groups on PEI chain to control the process of PB crystallization. The structure and morphology of smPB were characterized by SEM, TEM, FTIR, UV-vis and XRD. The photothermal conversion effect of smPB in aqueous solution was tested by sunlight from the solar simulator. The catalytic degradation efficiencies of smPB Fenton, photo-Fenton and photothermal-Fenton were tested under different catalytic conditions.Result The results showed that the photothermal conversion rate of smPB was about 90%. The temperature of 100 mL aqueous solution containing 20 mg smPB increased by about 8.8 ℃ at the condition of sunlight power irradiation for 1 h. Under the photothermal condition, the degradation rate was more than 99% within 40 min when 100 mL MB(ρ=20 mg/L) was degraded by 20 mg smPB in photothermal-Fenton catalysis.Conclusion The preparation method of smPB is simple and has many functions such as photothermal conversion, photo-Fenton and Fenton. The catalytic degradation efficiency of smPB photothermal-Fenton is greatly improved compared with Fenton or photo-Fenton, and the photothermal effect has a promoting effect on photo-Fenton.

Abstract:Objective Xylaria has valuable medicinal value and high economic value. Xylaria species collected from abandoned nest of termites were identified, and its liquid fermentation and solid culture conditions were optimized. The antibacterial and antioxidant activities of liquid fermentation product were determined. The study aimed at providing reference for exploitation and application of Xylaria escharoidea.Method The morphology observation and ITS sequencing were used to identify Xylaria species. The effects of adding different carbon sources, nitrogen sources and metal ions in liquid fermentation on mycelial growth were investigated. The effects of adding amino acids in solid medium on stromata growth were also analyzed. Furthermore, the antibacterial and antioxidant activities of liquid fermentation product were determined through plate bacteriostatic method and DPPH method.Result The collected strains were identified as X. escharoidea based on morphology and molecular data. The optimum carbon source in liquid fermentation was soluble starch, the optimum nitrogen source was silkworm pupa powder, and the optimum inorganic salt was MgSO₄. The optimum liquid medium component screened by orthogonal test was soluble starch 4% (w), silkworm pupa powder 0.6% (w) and MgSO₄ 0.06% (w). All valine, isoleucine and threonine could significantly promote the growth of stromata in solid medium. The antibacterial effect of liquid fermentation product was significantly better than that of potassium sorbate, and the antioxidant activity to DPPH was (75.19±2.08)%, significantly superior than that of vitamin E.Conclusion The optimized liquid fermentation and solid culture conditions can increase mycelial yield and promote stromata growth. The liquid fermentation product of X. escharoidea has excellent antibacterial and antioxidant activities, and possesses high exploitation and utilization value.

Abstract:Objective To explore the effects of different coupling modes of water-fertilizer on root zone soil quality and water use of Coffea arabica under shade.Method C. arabica was chosen as test material, under 30% shading degree, three irrigation levels (W_H: 1.2 Ep, W_M: 1.0 Ep, W_L: 0.8 Ep) and three fertilization levels (F_H: 530.00 kg·hm^-2, F_M: 353.33 kg·hm^-2, F_L: 176.67 kg·hm^-2) were completely designed with a total of nine treatments. The response laws of soil nutrient, microbial quantity, enzyme activities, dry mass and irrigation water use efficiency in root zone of C. arabica to water-fertilizer regulation were analyzed, and soil quality was comprehensively evaluated by combining membership function with factor analysis, and then the optimal water-fertilizer coupling mode of C. arabica was found by TOPSIS comprehensive analysis.Result Irrigation level and fertilization level had significant effects on soil nutrient, microbial quantity, enzyme activities (except catalase in autumn), root dry mass, stem dry mass, total dry mass and irrigation water use efficiency of C. arabica root zone. The average seasonal values of nitrate nitrogen, available phosphorus and available potassium contents in F_HW_L treatment were the highest. The average seasonal values of soil microorganism quantity and enzyme activities were the highest in F_MW_H treatment. Compared with F_LW_L treatment, F_HW_L treatment increased the average seasonal values of soil nitrate-nitrogen, available phosphorus and available potassium contents by 72.61%, 154.01% and 7.37%, respectively; F_MW_H treatment increased the average seasonal values of soil bacteria, fungi and actinomycetes number by 121.81%, 61.73% and 41.43%, respectively, and increased the average seasonal values of urease, catalase and phosphatase activities by 46.67%, 42.74% and 22.55%, respectively. There was a significant positive correlation between soil nitrate nitrogen content and catalase activity. The number of soil bacteria, fungi and actinomycetes were significantly positively correlated with the activities of urease, catalase and phosphatase, respectively. The combination of membership function and factor analysis showed that soil quality index of F_MW_H treatment was the highest (0.75). The total dry mass (38 011.50 kg·hm^-2) of F_MW_H treatment was the highest, and the irrigation water use efficiency (7.88 kg·m^-3) of F_MW_L treatment was the highest. However, TOPSIS method showed that the comprehensive benefit (soil quality, dry matter and irrigation water use efficiency) of F_MW_M treatment ranked the first, followed by F_MW_H treatment.Conclusion Under 30% shading degree, F_MW_M treatment was the best coupling mode of water-fertilizer for improving soil quality and promoting efficient production of C. arabica .

Abstract:Objective To explore the impacts of biotic and abiotic factors on the growth-defense physiological traits of invasive plant Alternanthera philoxeroides at large spatial scales, and provide a theoretical basis for dynamic prediction of invaded communities and bio-control under the global environmental change.Method We totally set up 72 plots invaded by A. philoxeroides with the area of 10 m×10 m per plot across 21°N-37°N in mainland China (36 terrestrial and 36 aquatic), and measured the nitrogen balance index (NBI), chlorophyll index (Chla), flavonoid index (Flav) and anthocyanin index (Anth) of A. philoxeroides in each plot. We then used the methods of regression analysis and canonical correspondence analysis (CCA) for examining the impacts of geography, climate, nitrogen nutrition, plant diversity and insect occurrence on these four physiological indexes.Result Regression analysis and CCA all showed that the Flav had significant positive relationship with latitude and significant negative relationship with rainfall. In regression analysis, the Chla for terrestrial and aquatic A. philoxeroides had significant positive relationship with longitude and nitrate nitrogen content, respectively, while the Anth for aquatic A. philoxeroides had significant negative relationship with latitude but positive relationship with annual mean air temperature. In CCA, the NBI for aquatic A. philoxeroides had strong negative relationships with Pielou evenness index, insect richness and the abundance of Agasicles hygrophila, but had strong positive relationships with Patrick richness index and Shannon-Wiener diversity index, while the Flav for aquatic A. philoxeroides showed the opposite distribution pattern with NBI in CCA ordination chart.Conclusion The longitude and nitrogen nutrition mainly affect the physiological growth traits of A. philoxeroides, while the latitude, climate and plant diversity mainly affect its chemical defense traits. Plant diversity and insect occurrence promot the ‘growth-defense’ tradeoff of aquatic A. philoxeroides.

Abstract:Objective The preparation of Grapholitha molesta sex pheromone microcapsule was investigated, and the sustained release effect of the microcapsule under indoor conditions was evaluated. Method Adopting G. molesta sex pheromone (E8-dodecenyl acetate) as core material, octenylsuccinate starch sodium, emulsifying starch-809, maltodextrin, ß-cyclodextrin and gelatin as wall materials, G. molesta sex pheromone microcapsule emulsion was prepared. The factors that affect the particle size distribution and encapsulation rate of the microcapsule emulsion, including the different proportions of the core material and the wall material, the sustained release ratio under indoor conditions and the mating disruption under field conditions were studied. Result The optimum wall material formula (mass ratio) of microcapsule emulsion was octenylsuccinate starch sodium∶ emulsifyingstarch-809∶gelatin∶maltodextrin∶β-cyclodextrin=5∶15∶0∶3∶2. The optimum preparation conditions were as follows: The mass ratio of wall material and core material was 10∶1, the shear velocity was 10 000 r/min, the shearing time was 2 min, the high pressure homogenization pressure was 20 MPa, the homogeneous time was 2 min; During the second homogeneous, 10 g liquid paraffin was added, the homogenization pressure was 20 MPa and the second homogeneous time was 4 min. The indoor sustained release experiments were conducted under 30, 40 and 50 ℃. The sex pheromones released from the microcapsules could be detected on the 91st day, whereas the unencapsulated sex pheromone was no longer detectable after 5 h. Field mating disruption study showed that microcapsule emulsion efficacy could last for 80 d and the effects of four sex pheromone dosages of 45, 75, 120 g/hm² and 75 g/hm² (refrigerating for one year) had no significant difference. Conclusion The G. molesta sex pheromones microcapsule emulsion significantly prolongs the duration period, and can be applied for the large-scale mating disruption control of G. molesta.

Abstract:Objective The purpose of this article is to monitor cotton pest in field based on Logistic algorithms and multi-spectral remote sensing images.Method The cotton areas with insect pests were selected as the research object. The multi-spectral remote sensing images of cotton field were acquired by UAV, and then pre-processed. Based on the spectral characteristics of cotton pests, the Logistic regression model was constructed by the reflectivity of pest-sensitive band and vegetation index to identify and monitor cotton pests.Result The cotton aphid, cotton red spider mite, and cotton bollworm identification models constructed by the soil adjusted vegetation index (SAVI) model and the normalized vegetation index (NDVI) model were the optimal models, and their accuracy for training sample and test sample reached 93.7% and 90.5% respectively the recall rate and F1 value were 96.6% and 93.5% respectively and the determination coeffecients of recognition models for three types of pests were 0.942, 0.851 and 0.663 respectively.Conclusion This model can identify the occurrence area of cotton aphid, cotton red spider mite and cotton bollworm, which can basically meet the requirements of precision plant protection operation in cotton field.

Abstract:目的 针对野外环境下断蕾机器人对多特征的变量目标快速识别难题，以及目标受到树叶、遮挡及光照影响精度的问题，提出多特征目标的快速识别方法。方法 提出对香蕉果实、果轴和花蕾这3个目标进行多尺度特征提取及模型分类，融合聚类算法设计新的目标候选框参数，提出改进YOLOv3模型及网络结构参数的YOLO-Banana模型；为了平衡速度和准确度，用YOLO-Banana和Faster R-CNN分别对变化尺寸的香蕉多目标进行试验，研究算法对识别精度与速度的影响。结果 YOLO-Banana和Faster R-CNN这2种算法识别香蕉、花蕾和果轴的总平均精度分别为91.03%和95.16%，平均每张图像识别所需时间分别为0.237和0.434 s。2种算法精度均高于90%，YOLO-Banana的速度相对快1.83倍，更符合实时作业的需求。结论 野外蕉园环境下，采用YOLO-Banana模型进行香蕉多目标识别，可满足断蕾机器人视觉识别的速度及精度要求。

Abstract:Objective In order to measure the number of tomato fruits at different ripening stages in greenhouse, a method based on color point cloud images was proposed.Method The image information of tomato in greenhouse was collected by KinectV2.0 on the mobile platform to synthesize the tomato plant point cloud, then the tomato plant point clouds from two perspectives were synthesized into a point cloud, and the point cloud of nearby tomato plant was obtained by depth information interception. The labeled point cloud data were input into the PointRCNN object detection network to train the prediction model and recognize tomato fruit in the tomato plant point cloud. Finally, support vector machine(SVM) classifier based on feature matrix training was used to classify ripeness of the identified fruits, and the number of tomato fruits at different ripening stages was obtained.Result The precision rate of the method based on PointRCNN object detection network for identifying the number of tomato fruits was 86.19% and the recall rate was 83.39%. The accuracy of SVM classifier based on feature matrix training for predicting the ripeness of tomato fruits was 94.27% in the training set and 96.09% in the test set.Conclusion The measurement method based on color point cloud images can accurately identify the number of tomato fruits at different ripening stages, and provide data supports for evaluating the yield of tomato fruits in greenhouse.

Abstract:Objective In order to accurately and effectively detect data anomalies from agricultural internet of things, one detection method of abnormal agricultural data based on broad convolution neural network (BCNN) was proposed for providing a reference for achieving high-quality data collection in agricultural internet of things.Method Firstly, the standardized agricultural data were encoded as polar coordinates, and then they were divided into subsets by sliding window mechanism. Subsequently, the data were reconstructed as matrix format. Finally, the BCNN was designed and trained for conducting anomaly detection. The experiment was conducted using the data monitored in the culturing farm environment. Result The sliding window mechanism could improve the detection ability and reduce the time consumption. The accuracy and F1 score of the designed BCNN in the datasets of air temperature and humidity, soil temperature and humidity were more than 97.5% and 0.985 respectively, which on average outperformed SVM, RF and CNN with the increase of 1.69%, 2.76%, 3.05% and 0.009 3, 0.0149, 0.0163, respectively. In particular, while handling the air and soil temperature and humidity data with high fluctuation , the gain in accuracy and F1 score ranged 3.61%–5.98% and 0.018 8–0.031 0, respectively. In addition, the proposed BCNN model has less time consumption of anomaly detection, only 1/6 to 1/7 of classical CNN model, and as well as with less hyperparameter.Conclusion The proposed data preprocessing (data coding, subset partition and reconstruction) method and BCNN model exhibit better performance on abnormal agricultural data.

Abstract:Objective Aiming at the special agronomy of small row spacing and shallow sowing depth of slot type Panax notoginseng seedling, a compact soil covering and compacting device for seed ditch was designed to improve the quality of P. notoginseng seedlings. Method On the basis of the field experiment to determine the range of matrix compactness with high emergence rate and the best seedling grade of P. notoginseng, the dynamic analysis of the contact between roller and soil was carried out to determine the relevant parameters of the soil covering and compacting device. The process of soil covering and compacting was simulated and analyzed using discrete element method. Taking ditching depth and forward speed of the planter as test factors, the covering soil thickness and consistency as the test indexes, soil trough test was carried out to verify whether the relevant structural parameters of soil covering and compacting device met the requirements.Result The results of field experiment showed that the range of substrate compactness was 200 to 400 kPa. The structural parameters of the soil covering and compacting device were as follows: The diameter of the pressing wheel was 150 mm, and the maximum spring stiffness was 140.5 N/mm. The simulation results showed that the soil covering thickness was 9.77 to 11.40 mm, the offset of grain spacing was 0.07 to 6.23 mm, and the offset of row spacing was 0.03 to 1.43 mm.The results of soil trough test showed that the optimal working parameters were as following: The trench depth was 25 mm, the forward speed of planter was 0.16 m/s, the average covering thickness was 11 mm, the consistency of soil covering thickness was 85.15%, and the compactness of substrate after compaction was 300 to 360 kPa.Conclusion According to the simulation analysis and soil trough test, the design of the soil covering and compacting device can meet the agronomic requirements of substrate compactness and covering soil thickness for P. notoginseng seedlings. The research results can provide references for the design of soil covering and compacting device of P. notoginseng.