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ϕRS138, a bacteriophage of the family Siphoviridae that lyses Ralstonia solanacearum, was isolated. The genomic DNA of ϕRS138 was 41,941 bp long with a GC content of 65.1 % and contained 56 putative open reading frames. The ϕRS138 genome could be divided into three regions based on similarities to other genomes: (1) a region containing genes encoding a putative transcriptional regulator and an integrase, similar to the prophage genes in Ralstonia solanacearum K60-1; (2) a region encoding proteins related to structural modules and virion morphogenesis, similar to genes in the Pseudomonas phages of the family Siphoviridae; and (3) a region highly similar to the genomes of other Ralstonia solanacearum strains.

The flowers of M. velutina were extracted with ethanol to obtain a crude extract that was consecutively extracted using n-hexane, dichloromethane, ethyl acetate and water. The crude extract and fractions were studied for the chemical composition and antioxidant and antidiabetic activities. The extracts had various phytoconstituents, namely steroids, flavonoids, tannins, saponins, alkaloids and glycosides. The aqueous extract had the highest total polyphenol (12.6 mg GAE/g extract) and total flavonoid (205.6 mg QE/g extract) content. The aqueous extract exhibited the strongest antioxidant activities in the ferric reducing antioxidant power assay (EC50 = 4.0 µg/mL), reducing power assay (EC50 = 78.1 µg/mL), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation assay (EC50 = 48.2 µg/mL), total antioxidant capacity assay (EC50 = 8.7 µg/mL) and 1,1-diphenyl-2-picrylhydrazyl assay (EC50 = 9.3 µg/mL). The aqueous extract showed the strongest inhibitory effect on the activity of α-amylase (IC50 = 376.6 μg/mL) and α-glucosidase (IC50 = 69.7 μg/mL). The results showed that the aqueous extract of M. velutina flowers can be a promising candidate for the control of diabetes and oxidative stress. This is the first report about the chemical components and antioxidant and antidiabetic activities of M. velutina flower extracts.

Though recently considered a therapeutic treatment for commercial broilers, little is known about the effects of bacteriophages on native, slow-growing birds. This study evaluated their efficacy against Salmonella enterica subsp. enterica serovar Typhimurium infected Noi chicken, a native Vietnamese broiler breed. In total, 420 birds were used in a completely randomized design consisting of seven treatments and four replicates of 15 birds. The treatments were NC (negative control), PC (positive control, S. Typhimurium challenged); NC+B1 and NC+B2 (negative control plus B1 or B2 bacteriophage, respectively); PC+B1, PC+B2 (positive control plus B1 or B2 bacteriophage, respectively) and PC+B1B2 (positive control plus both B1 and B2 bacteriophages). After four weeks of infection, the mortality rate in the PC group was 51.1% compared with 11.1% in the PC+B1B2 treatment. Bacteriophage administration had resulted in increased weight gain and decreased feed conversion ratio, particularly when both phages were included in the treatment (p<0.001). Moreover, the relative percentage of carcass weight was lowest in the PC treatment (66.9%) (p<0.001), whereas the other treatments registered similar carcass weight values. Regarding the internal organs, liver weight percentage was higher in the non-treated Salmonella group, and enlarged spleens were also noted in infected chickens even when treated with bacteriophages. The correlation between phage administration and blood parameters was unclear. Although the use of two bacteriophages for therapy was determined to be preferable for the majority of the criteria examined, further genetic characterization of the phages will be required before they can be widely used in chicken farms.

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