Biocontrol science最新文献

The fungal biocontrol agents, Cladosporium sp. have great economic importance on account of their beneficial effects on the integrated pest management (IPM) program. The different species of this genus can control different arthropod pests like sweetpotato whitefly, sugarcane woolly aphid, two-spotted mite, cotton aphid, cotton leaf worm, red spider mite, armyworm; and different plant diseases like- rice blast, wheat stripe rust, chrysanthemum white rust, etc. Chemical pesticides are a common practice by the user to protect their crops from these pests. But the intensive use of chemical pesticides has harmful impacts on human health and ecosystem functioning, and they also reduce plant protection sustainability. Sustainable plant protection could be achieved through the reduction of chemical pesticides, resulting in minimal impact on the environment without compromising crop yields. This review was written based on biocontrol methods using Cladosporium sp. which is an alternative option for pest management. Continued research concerning the commercialization of these biocontrol agents as biopesticides may contribute to sustainable plant protection.

A specific DMPO-OH adduct signal (1:2:2:1)related to hydroxyl radical generation in a longterm stored improved iodide formulation, tentatively designated as the distilled KMT reagent which prepared from a pH 0.3 solution containing FeCl₃, EDTA, KI and ethanol termed the KMT reagent, was detected by electron spin resonance (ESR) spectroscopy.Although the color intensities of N,N,N,N-tetramethyl-p-phenylenediamine (TMPD) and N,N-diethyl-p-phenylenediamine (DPD) differ, the mixture of the long-term stored distilled KMT reagent and TMPD exhibited a purple color similar to Wurster's blue, and the mixture of the long-term stored distilled KMT reagent and DPD exhibited a pink color similar to Wurster's red. There is a possibility that the long-term stored distilled KMT reagent may possess with the ability to generate a hydroxyl radical.

This study determined the prevalence of Staphylococcus aureus in food of animal origin, investigated its antimicrobial susceptibility profiles and antimicrobial-resistant genes encoding resistance to methicillin (mecA), penicillin (blaZ), and vancomycin (vanA). Two hundred and sixty food samples, including raw retail milk, meat, and meat products, were obtained from local retail shops in Mansoura city, Egypt. The overall prevalence of S. aureus in the total examined food samples was 32.69% (85/260). Methicillin-resistant S. aureus (MRSA) was identified in 11.15% (29/260) of the tested food samples. S. aureus indicated a high resistance to nalidixic acid, penicillin, ampicillin, cefuroxime, trimethoprim/sulfamethoxazole, and azithromycin. The multiple antibiotic resistance (MAR) rate was 89.4% of the total S. aureus isolates, and MARindex ranges from 0.05-0.64. Genotypically, mecA and blaZ genes were identified in a percentage of 34.11% and 82.35%, respectively, while no isolates harbored the vanA gene. The presence of MAR S. aureus particularly, MRSA in food samples, is of great concern and represents a possible threat to the community. Therefore, the study's findings highlight the importance of establishing vigilant food safety practices for food handlers to inhibit the transmission of S. aureus through the food chain to reduce public health risks.

It is necessary to know the appropriate bacterial culture temperature and stock temperature to carry out high-precision preservative efficacy tests. In this study, we investigated whether the temperature conditions within the culture or stock affect the survivability or growth activity of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. We found that the cold stocking condition affected the survivability of P. aeruginosa, but not that of E. coli and S. aureus. Furthermore, stocking temperature affects the growth activity of E. coli, P. aeruginosa and S. aureus, and the effect on P. aeruginosa was greater than that on the others. However, the attenuating effect on P. aeruginosa was reversed by culturing into fresh medium for up to six weeks after stocking. These results suggest that cold stress during stocking may affect the growth activity of P. aeruginosa. The results of this study should provide knowledge for the precise evaluation of preservative efficacy in cosmetics.

Acanthamoeba castellanii is a ubiquitous organism found in environmental water. The amoeba is pathogenic to toward humans and is also a reservoir of bacteria of the genus Legionella, a causative agent of legionellosis. Oakmoss, a source of natural fragrance ingredients, and its components are antibacterial agents that are specifically active against the genus Legionella. In the present study, oakmoss and its components were investigated for their inhibitory effects on total (extra- and intracellular) Legionella pneumophila within A. castellanii and on L. pneumophila within A. castellanii. Among the oakmoss components, 3-hydroxy-5-methylphenyl 2,4-dihydroxy-6-methylbenzoate (1), 3-methoxy-5-methylphenyl 2,4-dihydroxy-6-methylbenzoate (2), and 8-(2,4-dihydroxy-6-(2-oxoheptyl)phenoxy)-6-hydroxy-3-pentyl-1H-isochromen-1-one (8) reduced the number of total bacteria (extra- and intracellular) in a test culture and also exhibited high amoebicidal activity against L. pneumophila within A. castellanii at concentrations lower than their IC₅₀ values for A. castellanii. In contrast, 6,8-dihydroxy-3-pentyl-1H-isochromen-1-one (5) reduced the total number of L. pneumophila and, also that of total bacteria after 24 h of treatment (P < 0.05), whereas the compound did not exhibit amoebicidal activity against L. pneumophila within A. castellanii at concentrations lower than its IC₅₀ value against A. castellanii. Thus, it is suggested that these oakmoss components could be good candidates for disinfectants to protect from Legionella infection.

There are various purification methods have been developed and applied to industrial wastewater with contaminated microorganisms. We previously reported that high-voltage pulsed discharge plasma with cavitation effectively kills Escherichia coli cells. We attempted to expand the application of this disinfection method by using microorganisms such as Bacillus subtilis, Deinococcus radiodurans, and Schizosaccharomyces pombe. These microbial cells were treated with the discharge plasma, and the cell viability, DNA damage, and morphological changes were analyzed to evaluate the bactericidal effect. Interestingly, D. radiodurans, a radio-resistant bacterium showed relatively high sensitivity to the discharge plasma. On the other hand, B. subtilis and S. pombe showed the resistance, showing both sporogenesis. The amount of DNA damage in the treated cells corresponded to the cell viability, but most of the treated cells did not show any morphological changes.

The statistical correlation between the number of oral streptococci and the results of ATP bioluminescence assay was examined and compared with the results from Streptococcus plate counts and an oral bacteria quantification system. Because a significant correlation was found between ATP (RLU) and the number of bacteria in the oral bacteria quantification system for all seven types of oral streptococci examined, ATP would reflect a conditions of oral hygiene. However, using this assay, it was observed it may be difficult to correctly evaluate bacteria that form aggregates. Furthermore, even a small number of bacteria (below 10⁵ CFU/mL) , which cannot be measured by the oral bacteria quantification system, could be estimated by using ATP bioluminescence assay. It was suggested that this assay could be used for quantitative evaluation of the effect of oral cleaning.

A kind of citrus fruit with special flavor, Citrus sudachi harvested in Japan, are exported to various countries. However, the Citrus sudachi needs to be sterilized using aqueous solution of sodium hypochlorite because there is a possibility of the adhesion of citrus bacterial canker (CBC) which is not found in Europe. Due to the sterilization with time-consuming work, a more effective decontamination technique is required. A decontamination method using ultraviolet (UV) light irradiation is thus anticipated. Especially, the use of light emitting diodes (LEDs) wi UV light has many advantages in terms of energy consumption, lifetime, and compactness； although an appropriate method is yet to be established. In this study, we evaluate the fundamental effectiveness of UV-LED decontamination on the basis of the bactericidal ability on CBC in petri dishes, using six kinds of UV-LEDs (265, 280, 285, 300, 310, and 365 nm) . For each irradiation, the resultant bactericidal abilities (BAs) were evaluated precisely taking into account the differences in their optical absorptions. In addition, BAs per unit photon number were also estimated, as a fundamental wavelength-dependence of BA. As a result, the effectiveness of UV-LED irradiation with relatively short wavelengths was demonstrated clearly.

The remote bactericidal effect of TiO₂ photocatalyst, i.e., the bactericidal effect away from the photocatalyst, was successfully achieved using a humidified airflow. The TiO₂ photocatalyst used was anatase-type TiO₂ nanoparticles (NPs) annealed with a low-temperature O₂ plasma. For comparison, anatase-type TiO₂ NPs annealed in the air were used. The bacteria, Bacillus subtilis, were placed away from the TiO₂ NPs. The plasma-assisted-annealed TiO₂ NPs significantly inactivated 99% of the bacterial cells in 5 h, whereas the pristine and air-annealed TiO₂ NPs inactivated 88-90% of the bacterial cells. The remote bactericidal effect of plasmaassisted-annealed TiO₂ NPs would be attributed to a larger amount of H₂O₂ molecules traveled by the airflow from the TiO₂ NPs. The molecules were generated by chemically reacting more photoexcited carriers on the TiO₂ surface with H₂O and O₂ in the airflow. These photoexcited carriers originated from more oxygen-based species adsorbed and more oxygen vacancies introduced on the TiO₂ surface by the plasma-assisted-annealing.