Complete genome sequence of a novel lytic phage infecting Aeromonas hydrophila, an infectious agent in striped catfish (Pangasianodon hypophthalmus).

The bacteriophage vB_AhM_PVN02 (PVN02), infecting Aeromonas hydrophila, was isolated from a striped catfish pond water sample in Can Tho City, Vietnam. The phage had high lytic activity with a latent period and burst size of approximately 20 min and 105 plaque-forming units per cell, respectively. Observation of the phage by transmission electron microscopy indicated that PVN02 belongs to the family Myoviridae. The genome of PVN02 is a double-stranded linear DNA with a length in 51,668 bp and a content of 52% GC. Among the 64 genes, 16 were predicted to encode proteins with predicted functions. No virulence or antibiotic resistance genes were found in the genome, suggesting it would be a useful biocontrol agent. Classification of the phage based on sequence comparisons, phylogenetic analysis, and gene-sharing networks was carried out, and it was found to be the first representative of a new species within a previously undefined genus in the family Myoviridae. This study confirmed that PVN02 is a novel lytic phage that could potentially be used as an agent to control Aeromonas hydrophila in striped catfish in the Mekong Delta, Vietnam.

Effects of maturity on physicochemical properties of Gac fruit (Momordica cochinchinensis Spreng.).

The aril around the seeds of Gac fruit is rich in fatty acids and carotenoids (lycopene and ß-carotene). Understanding how these qualities are affected by fruit maturity at harvest may identify indices for quality assessment. Some physical and chemical properties of Gac fruit were determined for fruit harvested between 8 and 16 weeks after pollination (WAP). Fruit respiration rates and ethylene production rates were assessed after harvest and up to 20 days in storage at 20°C. Fruit harvested at 14 WAP had the highest oil (0.27 ± 0.02 g/g DW), lycopene content (0.45 ± 0.09 mg/g FW), and ß-carotene content (0.33 ± 0.05 mg/g FW) which declined by 16 WAP. External skin color and aril TSS were indicative of oil and carotenoid contents in aril. Skin color, TSS and potentially firmness were good indices of fruit quality. Harvesting less mature fruit at 12 WAP would be practical as the fruit were firmer and more capable of transport; however, quality during postharvest ripening may be limited. Fruits continued to ripen after they were harvested and an ethylene peak in the least mature fruit may reflect a climacteric behavior but this needs further investigation.

Allergenicity suppression in natural latex surgical gloves.

By a revised manufacturing process we aimed to obtain latex surgical gloves without immediate allergenicity, and also to determine a simple physical technique by which to estimate this allergenicity. Five glove samples were evaluated for allergenicity by physical and biochemical methods and by skin tests at the University Allergy Centre. Three groups of allergic patients with documented anaphylaxis to surgical gloves, positive skin tests to latex extract and specific IgE to latex (RAST Pharmacia greater than or equal to class II), volunteered for the study. The protein content, the in vitro allergenic potency of glove supernatants (RAST inhibition) and the skin test results with glove supernatants were lower in washed gloves than in non-washed samples (P less than 0.02 to P less than 0.009). The supplementary effect of glove sterilization at 120 degrees C (for 1 h in saturated steam) was obvious. The protein content became undetectable in four of the five glove supernatants, and skin tests results with sample supernatants were decreased (M +/- SEM = 0.68 +/- 0.29 mm vs 3.06 +/- 0.61 mm with non-sterilized gloves), P less than 0.009 by Wilcoxon test. With the Spearman test there was a significant correlation (P = 0.029) between the mean wheal size, obtained with supernatants (Groups 1 and 2) and electrical conductivity. Skin tests through pieces of gloves randomly distributed and coded were decreased by sterilization: 0.66 +/- 0.25 mm vs 2.86 +/- 0.45 mm, P less than 0.0001. Thus, it is possible to decrease glove allergenicity by washing them after mould forming and then sterilizing with steam. Electrical conductivity may be a simple parameter for revealing allergenicity.