Overgrowth of Agrobacterium tumefaciens has frequently been found in Agrobacterium-mediated plant transformation. This overgrowth can reduce transformation efficiency and even lead to explant death. Therefore, this research investigates an alternative way to mitigate or eliminate Agrobacterium after transformation using a bacteriophage. To develop this alternative method, we conducted effectiveness studies of two lytic bacteriophages (ΦK2 and ΦK4) and performed an application test to control Agrobacterium growth after transformation. According to plaque morphological characterization and molecular analysis, the two bacteriophages used in this experiment were distinct. Moreover, some stability physicochemical and growth kinetics, such as adsorption time and susceptibility test, also showed that both bacteriophages differed. On the other hand, the optimum temperature and pH of both phages were the same at 28–30 °C and pH 7. Further investigation showed that both ΦK2 and ΦK4 were able to reduce the overgrowth of A. tumefaciens post transformation. Moreover, applying the cocktail (mixture of ΦK2 and ΦK4) with antibiotic application eradicated A. tumefaciens (0% overgrowth percentage). This result indicates that the application of bacteriophage could be used as an alternative way to eradicate the overgrowth of A. tumefaciens subsequent to transformation.

Objective: The present study aimed to isolate and examine the characteristics of endophytic bacteria from kenikir (Cosmos caudatus Kunth.) leaves, to determine the endophytic bacteria capable of producing flavonoids, and to test their potency as anticancer and antimicrobial.Methods: The isolation of endophytic bacteria from C. caudatus Kunth. leaf was conducted by technical surface sterilization. Each of these isolates was produced from the insulation and then cultured on a liquid medium of 0.1% soluble starch, 0.5% peptone, and 0.15% yeast extract with a pH of 7 which have been incubated in room temperature for 5 days with agitation of 120 rpm and extracted with ethyl acetate solvent. The extract was then tested for flavonoid content using thin-layer chromatography method. The anticancer ability of flavonoids was tested by brine shrimp lethality test (BSLT) method, while that for antimicrobial, the test used paper disc method.Results: A total of 15 isolates of endophytic bacteria were successfully isolated from the kenikir leaves, but only 4 isolates produced flavonoids, among others PKM 1 (Serratia sp.), PKM 2 (Neisseria sp.), PKM 17 (Acinetobacter sp.), and PKM 19 (Yersinia sp.). BSLT test results showed that the flavonoids cause mortality in Artemia salina leach with LC50 as much as 16.736 in PKM 17, 17.267 in PKM 2, 18.672 in PKM 1, and 23.411 in PKM 19. The flavonoids also inhibited the growth of pathogens in human-based antimicrobial test results.Conclusion: Flavonoids produced by four endophytic bacterial isolates from kenikir leaves have great potential as anticancer and antimicrobial.

Salmonella sp. resistance against various antibiotics is one of the current health problems. An alternative to dealing with Salmonella sp. is using a bacteriophage-based biocontrol. In this study, the isolation of bacteriophages originated from Kencong and Puger areas in Jember Regency East Java, which was prone to food poisoning cases. Eleven bacteriophages were isolated from washing-water samples (φSC1, φSC2, φSC3, φSC4, φSC5), food samples (φSM1, φSM2, φSM3), and fish-waste samples (φSUT, φSP1, φSP2). The result showed that φSC3, φSC4, φSC5, and φSM1 have broad infection capabilities to the genera of Salmonella, Escherichia, and Staphylococcus. All isolates were classified as bacteriophages with DNA nucleic acids. The TEM morphological observations indicated that φSC4 isolates belong to the Podoviridae while φSP1 isolates belong to the Myoviridae. These results suggest that the phages could potentially be used for biocontrol purposes. However, further characterization, viability measurement and activity are needed before their use in food applications against foodborne pathogens.