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Although the spread of plasmid-mediated antibiotic-resistant bacteria is a public health concern, food contamination with plasmid-mediated antibiotic-resistant Escherichia coli in Vietnam has not been well investigated. This study aimed to describe the prevalence of colistin-resistant, carbapenem-resistant, and endemic blaCTX-M in extended-spectrum β-lactamase (ESBL) producing E. coli isolates. Colistin and carbapenem-resistant ESBL-producing E. coli were isolated from chickens in Vietnam and Japan. Colistin-resistant and AmpC/ESBL-producing E. coli (52% and 93%, respectively) were detected in chickens from Vietnam, in comparison to 52.7%, AmpC/ESBL-producing E. coli found in chicken from Japan. Carbapenem-resistant E. coli has not been isolated in Vietnam and Japan. Genotyping revealed that colistin-resistant E. coli harboured mcr-1, and most of the AmpC/ESBL-related genes were blaCTX-M-55 and blaCTX-M-65 together with blaTEM in Vietnamese chickens and blaCMY-2 in Japanese chickens. Multi-drug resistance analysis showed that ESBL-producing E. coli isolates had greater resistance to quinolones, streptomycin, and chloramphenicol than colistin-resistant E. coli isolates from Vietnam, suggesting the selection of multiple antibiotic resistance genes in ESBL-producing E. coli. In conclusion, colistin-resistant E. coli was detected in approximately half of the chicken samples, the majority of which harboured mcr-1. The high prevalence of ESBL-producing E. coli has remained constant in the last 5 years. The predominant blaCTX-M in ESBL-producing E. coli was blaCTX-M-55 or blaCTX-M-65, with the coexistence of blaTEM in Vietnam. These results can be implemented in monitoring systems to overcome the development of antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Chemical control has become less effective for the invasive weed species horseweed (Conyza canadensis) found in tangerine (Citrus reticulate) orchards of Korea. The dose–response assays of the biotypes of C. canadensis collected in 2017 from the Jeju province of Korea demonstrated that the amount of glyphosate needed for 50% growth reduction (GR50) in the glyphosate-resistant (GR) biotype was up to 100 times greater than that in the glyphosate-susceptible (GS) biotype (0.328 kg a.e. ha−1). However, the mechanism of resistance in the GR populations of C. canadensis in Korea is unknown. Therefore, this study aimed to determine the mechanism of resistance to glyphosate in the Korean C. canadensis populations. Shikimic acid accumulation and 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS) gene expression were analyzed in a GR and a GS biotype of C. canadensis. The GR biotype showed less shikimic acid accumulation than the GS biotype. A target point mutation in the sequence encoding the Pro 106 of EPSPS1 was not found after sequencing the GR biotype. Moreover, the expression level of EPSPS1 was not altered significantly following application of glyphosate to the GS and GR biotypes, whereas the levels of M10 and M11 ABC transporter genes which play an important role in plant growth and nutrition, and the interaction of the plant with its environment were found to be slightly higher in the glyphosate-treated GS and GR biotypes than the untreated control plants. Our results show that M10 and M11 are likely to be involved in the glyphosate resistance mechanism in C. canadensis. Consequently, non-chemical control methods should be implemented to manage or slow the spread of glyphosate resistance in C. canadensis. [ABSTRACT FROM AUTHOR]

Aims: The objective of this study was to analyze the responses of the soil fungal community to the afforestation of cropland with single and mixed tree species. Methods: We investigated changes in soil fungal community composition, diversity, structure and functional groups in the topsoil (0–20 cm) following afforestation. Six forest types were analyzed in this study: Robinia pseudoacacia (RP), Platycladus orientalis (PO), Pinus tabuliformis (PT), Robinia pseudoacacia + Platycladus orientalis (RPPO), Robinia pseudoacacia + Pinus tabuliformis (RPPT), and Platycladus orientalis + Pinus tabuliformis (POPT). Results: Soil fungal community composition and diversity significantly varied among cropland and forestland samples. Afforestation generally reduced soil fungal diversity and altered functional groups, and these variations were mainly mediated by tree species. Rare genera play an important role in the soil fungal network among cropland and forestland samples. Soil available phosphorus (AP) explained the largest portion of the variance in the soil fungal community. Soil available nutrients and microclimate were significantly associated with soil fungal diversity and richness. Conclusions: Our observations indicate that afforestation of cropland fundamentally restructures soil fungal community composition, structure, diversity and functional groups. Nutrient availability was a principal factor regulating fungal community composition following afforestation. [ABSTRACT FROM AUTHOR]

Background: Between 2016 and 2019, 265 cases of Zika virus (ZIKV) infection were reported in Vietnam, predominantly in southern Vietnam. In 2016, a case of ZIKV-associated microcephaly was confirmed in the Central Highlands, and several members of the infant's family were confirmed to be infected with ZIKV. The study aims to determine the level of immunity to ZIKV in the general population of the ZIKV epidemic region.Methods: A total of 879 serum samples were collected from 801 participants between January 2017 and July 2018, during and after the ZIKV epidemic in Vietnam. The samples were tested for anti-ZIKV immunoglobulin M (IgM) and immunoglobulin G (IgG), and anti-dengue virus (DENV) IgG antibodies using enzyme-linked immunosorbent assays (ELISA). Plaque-reduction neutralization test (PRNT) for ZIKV was performed on all samples, and for DENV on the samples that ZIKV neutralizing antibody positive.Results: A total of 83 (10.3%) participants had anti-ZIKV IgM. Of the 83, 6 were confirmed to be ZIKV antibodies positive using PRNT and anti-ZIKV IgG ELISA. Of the 718 participants who were anti-ZIKV IgM negative, a further 3 cases were confirmed as positive for antibodies against ZIKV. Of the 9 participants with ZIKV infection, 5 lived in the same village as the infant with ZIKV-associated microcephaly and the other 4 lived in 2 neighboring communes. Repeat samples were collected from the 83 ZIKV IgM positive participants 1.5 years after the first collection. No new cases of ZIKV infection were detected. In addition, 2 of 3 participants with anti-ZIKV NS1 IgG demonstrated a 4- to 8-fold increase in ZIKV neutralizing antibody titer.Conclusions: ZIKV was present in the area around Krong Buk, with the rate of ZIKV-specific antibodies was 1.1% in the community since at least 2016. While the low levels of circulation together with low seroprevalence suggests a limited outbreak in the region, the results also reflect on low levels of protective immunity to Zika within the population. These results provide a better understanding of the current ZIKV epidemic status in the region and demonstrate a need for implementation of more effective ZIKV infection control measures. [ABSTRACT FROM AUTHOR]

This study was conducted to examine total phenolic contents of Sorghum bicolor (L.) Moench shoot extracts in different cultivars andunder different extraction methods by HPLC analysis. In the first experiment, five cultivars of sorghum (Milyang-1ho, Milyang-5ho, Donganme, Hwanggumchal and Nampungchal) were extracted by soaking in distilled water for 24h at room temperature and boiling for 2 h, followed by filtering and evaporating. For the second experiment, focus was given to a known allelochemical, the phenolic compound 4-hydroxybenzoic acid. Hwanggumchal, the cultivar with the highest 4-hydroxybenzoic acid content from the first experiment, was chosen for optimizing phenolic compound extraction under different conditions such as solvent (distilled water or ethanol), temperature (4o, 25o and 40°C), and time (24, 48 and 72 h). An HPLC system was used to quantitatively determine total phenolic contents of extracts. Results showed that, between the five cultivars, Donganme had the highest total phenolic compounds (402.6 mg/l), while Hwanggumchal had the highest amount of 4-hydroxybenzoic acid (96.0 mg/l). In the second experiment, the highest amount of total phenolic compounds was obtained when the sorghum samples were extracted in ethanol by soaking for 72 h at 40°C, while the lowest amount was obtained by soaking 72 h at 4oC in distilled water. The study and application of the allelopathy phenomenon in weed control is essential for the protection of the environment. If adopted successfully, it could lead to significant accomplishments for sustainable agriculture. [ABSTRACT FROM AUTHOR]

To investigate the dissemination of ESBL/pAmpC-producing E. coli within the food distribution system of Ho Chi Minh City (HCMC), Vietnam, the prevalence of ESBL/pAmpC-producing E. coli strains in chicken meat, pork, beef, and fish/shrimp samples obtained from slaughterhouses, a wholesale market, and supermarkets was examined. Among the total of 330 collected food samples, ESBL/pAmpC-producing E. coli was detected in 150 samples (45.5%). The highest prevalence of these isolates was in chicken meat (76/82, 92.7%), followed by pork (32/92, 34.8%), beef (18/74, 34.3%), and fish/shrimp (24/82, 29.3%). A total of 342 strains of ESBL/pAmpC-producing E. coli were isolated from 150 positive food samples. The most prevalent genes responsible for ESBL or pAmpC activity belonged to the CTX-M-9 (110/342, 31.2%), CTX-M-1 (102/342, 29.8%), and CIT (118/342, 34.5%) groups. To our knowledge, this is the first report of the high occurrence of pAmpC (37.1%) in animal-based food in Vietnam. Among the 342 total ESBL/pAmpC-producing E. coli isolates, 276 (80.7%) were resistant to at least 6 antibiotic agents. Notably, high percentages of resistance to ciprofloxacin and fosfomycin were found in isolates from chicken (80.5% and 50.8%, resp.). These findings demonstrate that animal-based food products in HCMC represent a major reservoir of ESBL/pAmpC-producing E. coli. [ABSTRACT FROM AUTHOR]

The agricultural industry has tried to develop effective herbicides, especially biological herbicides, with less impact on our agricultural environment. Recently, allelopathy has emerged as a potential alternative to chemical herbicides for weed management. Allelopathy is defined as "any direct or indirect, harmful or beneficial effects of one plant on another through the production of chemical compounds that are released into the environment." Sorghum bicolor (L.) Moench, a species that originates from Africa and is widely cultivated in both tropical and sub-tropical regions, is considered as a rich source of allelochemicals with biological weed control ability. Chemical constituents of sorghum include tannins, phenolic acids, anthocyanins, phytosterols and policosanols. Investigations on underground parts of sorghum indicate that sorgoleone is in charge of the weed control activity, while phenolic compounds play a vital role in its herbicidal activity on aerial parts of weeds. This review aims at providing up-to-date and comprehensive information about allelopathy in sorghum and further application of sorghum extract in weed control. [ABSTRACT FROM AUTHOR]

For many applications it would be desirable to be able to control the activity of proteins by using an external signal. In the present study, we have explored the possibility of modulating the activity of a restriction enzyme with light. By cross-linking two suitably located cysteine residues with a bifunctional azobenzene derivative, which can adopt a cisor trans-configuration when illuminated by UV or blue light, respectively, enzymatic activity can be controlled in a reversible manner. To determine which residues when crosslinked show the largest "photoswitch effect," i.e., difference in activity when illuminated with UV vs. blue light, >30 variants of a single-chain version of the restriction endonuclease Pvull were produced, modified with azobenzene, and tested for DNA cleavage activity. In general, introducing single cross-links in the enzyme leads to only small effects, whereas with multiple cross-links and additional mutations larger effects are observed. Some of the modified variants, which carry the cross-links close to the catalytic center, can be modulated in their DNA cleavage activity by a factor of up to 16 by illumination with UV (azobenzene in cis) and blue light (azobenzene in trans), respectively. The change in activity is achieved in seconds, is fully reversible, and, in the case analyzed, is due to a change in Vmax rather than Km. [ABSTRACT FROM AUTHOR]