RESUMEN
A 2-step microtiter plate assay was developed to simultaneously check wide values of MOIs of bacteriophages, ranging between MOI-0.0001 and MOI-10000 in the first step and optimize the most suitable MOI (lowest quantity of phage) for inhibiting the growth of the target bacteria in the second step. The results of the first step revealed that the effective MOI of coliphage-ɸ5 for controlling the growth of antimicrobial resistant (AMR) E. coli was between 4.36 and 43.6 for E.coli-EC-3; between 38.2 and 382 for E.coli-EC-7 and between 81.5 and 815 for E.coli-EC-11. The optimum MOI of coliphage-ɸ5 determined in the second step was 17.44, 191 and 326 for controlling the growth of E.coli-EC-3; E.coli-EC-7 and E.coli-EC-11, respectively. The effective MOI of vibriophage-ɸLV6 for controlling luminescent Vibrio harveyi in the first step was found to be between 18.3 and 183 and the optimum MOI as determined in the second step was 79. The sequential 2-step microtiter plate method yielded faster optimization of MOI and was economical compared to the conventional flask method. The measurement of OD values at 550â¯nm and 600â¯nm showed similar trend and replicate data from 5-wells and 3-wells yielded identical pattern indicating that the measuring absorbance data in 3-replicate wells at either OD550 or OD600 is sufficient to generate quantifiable phage lysis data. The 2-step microtiter plate assay finds application in phage therapy in human health care, agriculture and animal agriculture for determining the optimum MOIs for selected bacteriophages.
Asunto(s)
Bacteriófagos , Terapia de Fagos , Animales , Colifagos , Escherichia coli , Humanos , VibrioRESUMEN
Newcastle disease vaccines hitherto in vogue are produced from embryonated chicken eggs. Egg-adapted mesogenic vaccines possess several drawbacks such as paralysis and mortality in 2-week-old chicks and reduced egg production in the egg-laying flock. Owing to these possible drawbacks, we attempted to reduce the vaccine virulence for safe vaccination by adapting the virus in a chicken embryo fibroblast cell culture (CEFCC) system. Eighteen passages were carried out by CEFCC, and the pathogenicity was assessed on the basis of the mean death time, intracerebral pathogenicity index, and intravenous pathogenicity index, at equal passage intervals. Although the reduction in virulence demonstrated with increasing passage levels in CEFCC was encouraging, 20% of the 2-week-old birds showed paralytic symptoms with the virus vaccine from the 18(th)(final) passage. Thus, a tissue-culture-adapted vaccine would demand a few more passages by CEFCC in order to achieve a complete reduction in virulence for use as a safe and effective vaccine, especially among younger chicks. Moreover, it can be safely administered even to unprimed 8-week-old birds.
Asunto(s)
Pollos/virología , Virus de la Enfermedad de Newcastle/patogenicidad , Enfermedades de las Aves de Corral/prevención & control , Vacunas Atenuadas/uso terapéutico , Vacunas Virales/uso terapéutico , Animales , Técnicas de Cultivo de Célula , Células Cultivadas , Embrión de Pollo , Pollos/inmunología , Virus de la Enfermedad de Newcastle/clasificación , Virus de la Enfermedad de Newcastle/crecimiento & desarrollo , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/virología , Cultivo Primario de Células , Vacunación , Vacunas Atenuadas/efectos adversos , Vacunas Atenuadas/inmunología , Vacunas Virales/efectos adversos , Vacunas Virales/inmunologíaRESUMEN
Efficacy of mint (Mentha arvensis) leaf and citrus (Citrus aurantium) peel extracts in retarding the quality changes in Indian mackerel during chilled storage was investigated. Mint leaf extract showed higher quantity of phenolics and superior in-vitro antioxidant activities than citrus peel extract. Gutted mackerel were given a dip treatment in mint extract (0.5 %, w/v) and citrus extract (1 % w/v), packed in LDPE pouches and stored at 0-2 °C. The biochemical quality indices viz. total volatile base nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), free fattyacids (FFA) were significantly (p < 0.05) lower in mint extract (ME) treated fishes compared to citrus extract (CE) treated and control fishes (C) without any treatment. Plant extract treatment significantly inhibited lipid oxidation in mackerel as indicated by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Aerobic plate count (APC) was markedly higher in C group followed by CE group throughout the storage period. As per sensory evaluation, shelf life of Indian mackerel was determined to be 11-13 days for C group, 13-15 days for CE group and 16-17 days for ME group, during storage at 0-2 °C.
RESUMEN
Newcastle disease vaccines