During 2003 and during late September of 2004, more than 1230 cases of gastroenteritis were reported in the south of Sinaloa State, north-western Mexico. All cases were attributed to the consumption of raw or undercooked shrimp collected at the Huizache-Caimanero lagunary system. Vibrio parahaemolyticus was identified by standard biochemical methods, and many strains were positive for PCR amplifications of the tlh and tdh genes and negative for the trh gene. A representative strain belonged to the O3:K6 serogroup. This is the first outbreak of gastroenteritis caused by the pandemic strains of O3:K6 V. parahaemolyticus in México.
Six Gram-negative coccobacilli were isolated from Pacific oysters (Crassostrea gigas) from Mexico and haemolymph of spider crabs (Maja brachydactyla) from Spain. All of the isolates grew as small green colonies on thiosulphate-citrate-bile salts-sucrose (TCBS) agar and were facultatively anaerobic, oxidase-positive and sensitive to the vibriostatic agent O/129. Repetitive palindromic PCR analysis revealed a high degree of genomic homogeneity among the isolates. Several phenotypic traits differentiated the isolates from the type strains of species of the genus Photobacterium. DNA-DNA relatedness between two representative isolates and their closest phylogenetic neighbours by 16S rRNA gene sequence similarity, Photobacterium aplysiae CAIM 14 T and Photobacterium frigidiphilum CAIM 20 T , was 44.01-53.85 %. We propose a novel species of the genus Photobacterium to accommodate the six isolates, with the name Photobacterium swingsii sp. nov. The type strain is CAIM 1393 T (5CECT 7576 T ).
A bacterial strain was taxonomically characterised by means of a genomic approach comprising 16S rRNA gene sequence analysis, multilocus sequence analysis (MLSA), the DNA G+C content, whole genome analyses (ANI and GGDC) and phenotypic characterisation. The strain CAIM 1540(T) was isolated from a cultured oyster Crassostrea corteziensis in La Cruz, Sinaloa state, México. The isolate was found to be catalase and oxidase positive, cells were observed to be motile, O/129-sensitive and facultatively anaerobic. The almost-complete 16S rRNA gene sequence placed this strain within the genus Vibrio; the closest related species were found to be Vibrio aestivus, Vibrio marisflavi, Vibrio maritimus and Vibrio variabilis with similarity values of 99.02, 97.05, 96.70, and 96.59 % respectively. MLSA of four housekeeping genes (ftsZ, gapA, recA, and topA) was performed with the closely related species. A draft genome sequence of strain CAIM 1540(T) was obtained. The DNA G+C content of this strain was determined to be 43.7 mol%.The ANI values with V. aestivus were 89.6 % (ANIb), 90.6 % (ANIm) and a GGDC value of 39.5 ± 2.5 % was obtained; with V. marisflavi the genomic similarities were 71.5 % (ANIb), 85.5 % (ANIm) and 20.2 ± 2.3 % (GGDC); with V. maritimus 72.6 % (ANIb), 85.7 % (ANIm) and 22.0 ± 2.0 % (GGDC); and with V. variabilis 72.6 % (ANIb), 85.8 % (ANIm) and 21.6 ± 1.6 % (GGDC). These ANI and GGDC values are below the threshold for the delimitation of prokaryotic species, i.e. 95-96 and 70 %, respectively. Phenotypic characters also showed differences with the closest related species analysed. The results presented here support the description of a novel species, for which the name Vibrio mexicanus sp. nov. is proposed, with strain CAIM 1540(T) (= CECT 8828(T), = DSM 100338(T)) as the type strain. In addition, we found that the recently described species Vibrio thalassae and Vibrio madracius might be a single species because the values of ANIb 95.8 %, ANIm 96.6 % and GGDC 70.2 ± 2.9 % are above the accepted species thresholds.
The science of the feeding and nutrition of crustaceans is still in development, and producers and feed manufacturers need better understanding of the digestibility of various nutrients. The most widely used method of determining digestibility in vivo in fish is based on the measurement of chromium oxide (which is incorporated into the diet) in feces. To use this method, it is essential to have an efficient means of collecting feces in the aquatic environment. In shrimp, this presents some difficulties because of their benthic feeding and coprophagic habits. This paper describes the development and testing of a low-cost modification of the ''Guelph'' system used for fish that allows the collection of feces from shrimp. The system performed extremely well and had clear advantages over the basic siphon system. The importance of having an easy and efficient method of collecting feces for in vivo assays is discussed.The science of the feeding and nutrition of crustaceans is still in development, and producers and feed manufacturers need better understanding of the digestibility of various nutrients. The methods used to determine feed digestibility range from gravimetric or total collection to the use of chro-
Ultrasonic nebulization was used as a novel method of chitosan (CH) and acidic electrolyzed water (AEW) application on table eggs; effects on preservation, quality and antimicrobial properties were investigated. The effect of the application of CH and AEW alone or in combination on eggs quality was evaluated in terms of weight loss, shell thickness, yolk colour, Haugh units and shell strength. Additionally, the application of CH and AEW as an antimicrobial agent was investigated in order to evaluate their efficacy against Salmonella enteritidis and Escherichia coli (ATCC 25922). A negative effect was observed by the sole application of AEW on eggshell thickness and strength. Conversely, the combination of AEW and CH improve eggshell strength, as well as avoid water losses. The use of CH alone stable Yolk colour values and Haugh units compared to control eggs during the storage time. The combination of AEW and CH reduced the antimicrobial activity. However, the sole application of CH or EAW was effective depending on the type of inoculation and the strain evaluated.
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