Exploration of ecological restoration of saline-alkali land based on NbS--Study on the salt resistance and desalination performance of three cash crops.

Soil salinization is one of the current global environmental problems. Current research on crops in saline-alkali land focuses on salt tolerance, but less on its ecological benefits. However, plants and the environment can interact and influence each other, which is the theory used to carry out Nature-based Solutions (NbS). Therefore, the research on crop plants with both ecological and economic benefits is novel and valuable work. Then three widely planted cash crops (Solanum melongena, Momordica charantia, Capsicum annuum) were selected for salt stress treatment (NaCl, 150mmol/L), some physiological indicators (chlorophyll, soluble protein, Proline (Pro), malondialdehyde (MDA)) of plant and the soil properties (electrical conductivity, pH, the soil salt content) were measured. The results showed that the salinity content of the three plant cultivation soils was significantly different (P<0.05) after the salt stress; all three crops had some desalination capacity, but Capsicum annuum had the strongest salt resistance and desalination capacity.

Isolation, identification, and pathogenicity of a ALV-K strain from Chinese indigenous chicken breed.

Subgroup K avian leukosis virus (ALV-K) is a new subgroup of avian leukosis virus (ALV) first identified in Chinese indigenous chickens in recent years. In this study, an ALV-K strain was isolated from Luhua chicken in Shandong province, China, and designated SD20LH01. The full-length genomic sequence of SD20LH01 was 7491 bp, which had the highest homology with ALV-K reference strains GDFX0601, GDFX0602 and GDFX0603. The nucleotide homology of env gene of SD20LH01 with reference strains of subgroup A, B, C, D, E, and J was ranged from 57.1 to 93.2%, while 94.1 to 99.4% with other ALV-K reference strains. The nucleotide difference of SD20LH01 mainly clustered with gp85 gene and U3 sequence when compared with the reference strain of ALV-K. In order to investigate the pathogenicity of SD20LH01, SPF chicken embryos were infected by yolk sac inoculation, and 1-day-old chickens were infected by intraperitoneal inoculation of SD20LH01. The results showed that yolk sac inoculation of SD20LH01 could induce persistent viremia, growth retardation and reduce the immune response to NDV and AIV-H9 vaccines. However, intraperitoneal inoculation in 1-day-old chickens could only induce a low level of viremia. In addition, no tumors were found in infected chickens during the animal experiments. This study enriched the genomic sequence data of ALV-K isolated in Chinese indigenous chickens, and laid a foundation for further study on the pathogenesis and prevention of ALV-K.

Pathogenicity of fowl adenovirus (FAdV) serotype 4 strain SDJN in Taizhou geese.

Hydropericardium hepatitis syndrome (HHS) is a fatal disease in chickens, mainly caused by fowl adenovirus serotype 4 (FAdV-4). Since June 2015, HHS has appeared in many provinces in China. The disease has spread from broilers to laying hens, breeders and Cherry Valley ducks, seriously endangering the health of the poultry industry in China. In July 2016, an infectious disease was noticed in a goose farm in Jinan, Shandong Province, China, and hydropericardium was the main finding in post mortem investigations. In the actual study, we isolated a FAdV-4 strain from the livers of naturally-infected goslings and designated it as SDJN. We first evaluated its pathogenicity by inoculating Taizhou geese at 10, 20, and 30 days of age with 10-7.15EID50/0.2 ml doses of the SDJN strain in 1 ml allantoic fluid via subcutaneous injection or oral infection. Clinical signs and pericardial effusion appeared in geese infected subcutaneously at 10 days of age, whereas 20- and 30-day-old geese were not susceptible to FAdV-4. The results of real-time PCR showed that the replication ability of FAdV-4 in geese correlated with the age. Furthermore, results from clinical chemistry showed that FAdV-4 damaged the liver and kidney in geese and the results paralleled viral load and gross lesions. Consequently, FAdV-4 was pathogenic in geese, and the pathogenicity was related to age and mode of infection. This study is the first experimental infection of FAdV-4 in geese, which will provide a basis for further understanding of the disease. RESEARCH HIGHLIGHTS Pathogenicity tests with a FAdV-4 were conducted in geese, which included data on clinical signs, gross pathology, histopathology, clinical chemistry and viral load. FAdV-4 could replicate in geese and HHS was successfully induced. Pathogenicity of FAdV-4 in geese was related to the age and routes of infection.

Duck viral infection escalated the incidence of avian pathogenic Escherichia coli in China.

Avian pathogenic Escherichia coli (APEC) causes high mortality in poultry flocks and often is complicated with viral infections, leading to large economic losses; however, little information is available on the epidemiological characteristics of this pathogen in ducks. Therefore, a systemic epidemiological investigation was performed on 325 duck farms from 13 provinces in China during the period of 1 April 2016 until 31 March 2018, covering 2 years. A total of 26 APEC strains were isolated from different farms in this study, and analysis showed that all of those isolates carried multiple virulence-associated genes and drug-resistance genes, which led to high pathogenicity (15/26), strong or moderate biofilm formation (24/26) and multidrug-resistant abilities (26/26). On the other hand, coinfection with APEC, H9 avian influenza virus (AIV) and Tembusu virus (TMUV) was very common on those farms (11/26), with APEC and TMUV sharing a similar morbidity peak (from May to September) and susceptibility (60% infections occurred in ducklings); thus, we speculated that the emerging TMUV infection escalated the APEC incidence in ducks. Finally, the data presented in this report enhance the current understanding of the epidemiology of APEC and different viral infections in ducks and provide additional insight into the critical factors that determine their pathogenicity. Meanwhile, the emergence of multidrug-resistant APEC strains and their coinfection with different viruses emphasize that preventive measures against such infections on poultry farms should be implemented immediately.

Global transcriptional profiles of Trichophyton rubrum in response to Flucytosine.

Trichophyton rubrum (T.rubrum) is one of the most common human fungal pathogens that cause chronic infections of the skin and nails. To identify antifungal responsive genes, cDNA microarray analysis was performed for T. rubrum to reveal global transcriptional profiles of drug-specific responses to 5-Flucytosine (5-FC). cDNA microarray was constructed from the T. rubrum expressed sequence tag (ESTs) database, the minimum inhibitory concentration (MIC) of 5-FC was determined, and microarray hybridization and data analysis were applied. The expression pattern of 7 genes observed by microarray was confirmed by the quantitative real-time reverser transcription polymerase chain reaction (RT-PCR). Data analysis indicated that a total of 474 genes were found differentially expressed, 196 showed an increase in expression and 278 showed a decrease in expression. Marked down-regulation of genes involved in nucleotide metabolism (such as CDC21), transcription (such as E2F1), and RNA processing (such as SGN1, RIM4 and NOP1) was observed. Other genes involved in signal transduction, chaperones, inorganic ion transport, secondary metabolite biosynthesis, amino acid transport, lipid transport and potential drug resistance mechanism were also affected by 5-FC. Quantitative real-time RT-PCR of the selected genes confirmed the reliability of the microarray results. This is the first analysis of transcriptional profiles in response to 5-FC for T. rubrum. The findings may be valuable for the identification of genes involved in mechanisms of action and mechanisms of antifungal drug resistance of 5-FC.

Transcriptional profiles of Trichophyton rubrum in response to itraconazole.

Trichophyton rubrum is the predominant causative agent for superficial dermatomycosis. In order to understand how triazole antifungal agents interact with dermatophytes, the gene expression response of T. rubrum to itraconazole was studied by large-scale gene expression profiling. A total of 670 genes were found to be responsive to itraconazole, including 305 that were up-regulated and 365 down-regulated. Most genes involved in lipid metabolism and especially in ergosterol biosynthesis were up-regulated in response to itraconazole, including ERG6, ERG7, ERG11, ERG24, ERG25 and ERG26. In addition, transcription of some genes involved in cell stress response, drug efflux, and small molecule transport was also affected by itraconazole. Differential expression of selected genes was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR). This is the first microarray hybridization analysis of T. rubrum exposed to a triazole antifungal agent.

Mutant-prevention concentrations of enrofloxacin for Escherichia coli isolates from chickens.

OBJECTIVE: To investigate the development of enrofloxacin resistance among Escherichia coli isolates obtained from chickens by determining mutant-prevention concentrations (MPCs) and sequence the quinolone resistance-determining regions (QRDRs) of gyrA and parC genes in selected isolates. SAMPLE POPULATION: 15 chicken-derived E coli isolates. PROCEDURES: For all isolates, MPC and minimal inhibition concentration (MIC) of enrofloxacin were determined. The MPCs and maximum serum drug concentrations attained with enrofloxacin doses recommended for treatment of E coli infections in chickens were compared. Mutation frequencies and QRDR sequence changes in gyrA and parC were also determined. RESULTS: In 2 of 15 E coli strains, MPCs were low (0.016 and 0.062 microg/mL), MPC:MIC ratios were 2 and 4, and the GyrA and ParC proteins had no mutations. In 9 susceptible isolates with a GyrA point mutation, MPCs ranged from 2 to 16 microg/mL. For isolates with double mutations in GyrA and a single mutation in ParC, MPCs were > 32 microg/mL (several fold greater than the maximal plasma concentration of enrofloxacin in chickens); mutation frequencies were also much lower, compared with frequencies for single-mutation isolates. CONCLUSIONS AND CLINICAL RELEVANCE: For E coli infections of chickens, MPC appears to be useful for determining enrofloxacin-dosing strategies. The high MPC:MIC ratio may result in enrofloxacin-treatment failure in chickens infected with some wild-type gyrA E coli isolates despite the isolates' enrofloxacin susceptibility (MICs 0.125 to 1 microg/mL). For infections involving isolates with high MPCs, especially those containing mutations in gyrA and parC genes, treatment with combinations of antimicrobials should be adopted.