To clarify serotype, drug resistance and genetic evolution of Rimerella anatipestifer in Guangdong.

The isolates of R. anatipestifer were isolated and identified from samples of the large-scale duck farms. Serotype was identified by glass agglutination test. The minimum inhibitory concentration was tested by double dilution method in test tube, and the drug sensitivity was analyzed. Whole genome sequencing technology was used to analyze the sequence characteristices and construct the genetic evolution tree of the core genome.

A total of 168 isolates of R. anatipestifer were isolated and identified. All serotype 1, 2, 3, 5, 6, 7, 8 and 10 were prevalent. Serotype 1 was dominant, reaching 54.17%(91/168), followed by serotype 2 (27.97%, 47/168). The 48 representative isolates were used for drug sensitivty test and sequence analysis. The isolates showed high drug resistance to gentamicin, kanamycin and ciprofloxacin hydrochloride, and the drug resistance rates were all more than 80%. The drug resistance rates to oxytetracycline, tetracycline hydrochloride, chlortetracycline hydrochloride, ofloxacin, norfloxacin, sulfadimidine and sulfamethoxydiazine were all more than 60%, and the drug resistance rates to amoxicillin, cefotaxime and spectinomycin were all less than 30%. The 48 representative isolates were resistant to 5−12 kinds of drugs, and there were 44 types of drug resistance spectrum. The whole genome sequences of 46 isolates were obtained successfully, and six drug-resistant genes were detected. The detection rates of drug-resistant geneserm(F) and tet(X) were 73.91% (34/46) and 82.60% (38/46), respectively. In addition, 95.65% (44/46) of the isolates carried more than two drug-resistant genes at the same time. Total 18 isolates (39.13%, 18/46) were typed successfully with 11 kinds of ST. Further genetic tree construction based on the core genome showed that all the sequenced isolates had a high similarity with the isolates from China in the multi-locus sequence typing (MLST) database, and mainly existed in the dominant clones of Clade 1 and Clade 3.

Serotype 1 is superior in the investigated R. anatipestifer isolates, and the drug resistance is serious. The drug-resistant genes and resistant phenotype have certain relevance. ST type has a high diversity. The genetic background of tested strains was similar with Chinese strains in MLST database. The results of this study can provide a basis for vaccine immunity prevention and drug therapy of R. anatipestife disease as well as for understanding the genetic evolution characteristics of R. anatipestife.

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.

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.

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.

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.

A molecularly imprinted polymer adsorbent with specific recognition for mycophenolic acid was synthesized for purification, enrichment and analysis of mycophenolic acid in silage.

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.

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.

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.

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.

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.

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.

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.

To study the difference of protein modification of silkworm(Bombyx mori) eggs during diapause induced by high or low temperature, and provide references for further exploration of molecular mechanism of insect diapause induction.

The stable diapause silkworm strains induced by high or low temperature were screened out by raising the bivoltine silkworm varieties. Using the selected strains as materials, the eggs were incubated at 25 and 15 ℃ respectively. Samples were taken at the sensitive stage and the head pigmentation phase for epigenetic studies. The differences of protein modification were detected by SDS-PAGE electrophoresis and Western blot.

The methylation level of protein in silkworm eggs in high temperature (25 ℃) group was always higher than that of low temperature (15 ℃) group, and there was significant difference at the head pigmentation phase. The levels of acetylation modification had always been significantly different between high and low temperature groups, and the high temperature group had significantly lower level compared with the low temperature group at the head pigmentation phase. The ubiquitination level of the low temperature group was always higher than that of the high temperature group, especially in the early stage of development. The levels of phosphorylation modification of both groups were high overall, and there was no significant difference between high and low temperature groups. The malonylation levels of protein in silkworm eggs did not change significantly between high and low temperature groups. The levels of succinylation modification of high and low temperature groups were always low, and there were obvious differential modification proteins in late developmental stage.

There are significant differences in the protein ubiquitination and acetylation modification level of silkworm eggs incubated at 25 ℃ compared with those at 15 ℃ throughout development, and the levels of methylation are significantly different at the head pigmentation phase, suggesting that methylation, ubiquitination and acetylation play important roles in early diapause induction process of silkworm.

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.

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.

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.

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.

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.

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.

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.

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.

To explore the effects of different coupling modes of water-fertilizer on root zone soil quality and water use of Coffea arabica under shade.

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.

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.

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 .

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.

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.

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.

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.

The preparation ofGrapholitha molesta sex pheromone microcapsule was investigated, and the sustained release effect of the microcapsule under indoor conditions was evaluated.

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.

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.

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.

The purpose of this article is to monitor cotton pest in field based on Logistic algorithms and multi-spectral remote sensing images.

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.

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.

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.

Aiming at fast recognition of multi-feature variable target by robot vision in field environment, and considering the problem that the accuracy of target is affected by leaves, shade and light, a fast recognition method of multi-feature target was proposed.

A multi-scale feature extraction and classification model was proposed for three targets including banana fruit, fruit axis and flower bud. New target candidate box parameters were designed using clustering algorithm. The network structure parameters of YOLOv3 model were optimized and the YOLO-Banana model was proposed. In order to balance the speed and accuracy, YOLO-Banana and Faster R-CNN were used to conduct experiments on banana multi-targets with varying sizes. The effects of algorithms on recognition accuracy and speed were analyzed.

The average accuracies of YOLO-Banana and Faster R-CNN algorithms on banana fruit, fruit axis and flower bud were 91.03% and 95.16% respectively, average recognition time per photo was 0.237 and 0.434 s respectively. Therefore the accuracies of two algorithms were both above 90%. YOLO-Banana had relatively 1.83 times faster speed than Faster R-CNN, better satisfying the requirement of real-time operation.

In the wild environment, utilization of YOLO-Banana model for banana multi-target recognition can meet the speed and accuracy requirements for visual recognition by the bud-breaking robots.

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.

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.

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.

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.

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.

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.

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.

The proposed data preprocessing (data coding, subset partition and reconstruction) method and BCNN model exhibit better performance on abnormal agricultural data.

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.

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.

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.

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.