Vibrio sp. ArtGut-C1, a polyhydroxybutyrate producer isolated from the gut of the aquaculture live diet Artemia (Crustacea)

BACKGROUND: Vibrio species display variable and plastic fitness strategies to survive and interact with multiple hosts, including marine aquaculture species that are severely affected by pathogenic Vibrios. The culturable Vibrio sp. strain ArtGut-C1, the focus of this study, provides new evidence of such phenotypic plasticity as it accumulates polyhydroxybutyrate (PHB), a biodegradable polymer with anti-pathogen activity, particularly in the marine larviculture phase. The strain was isolated from the gut of laboratory-reared Artemia individuals, the live diet and PHB carrier used in larviculture. Its main phenotypic properties, taxonomic status and genomic properties are reported based on the whole-genome sequencing. RESULTS: Vibrio sp. ArtGut-C1 yielded 72.6% PHB of cells' dry weight at 25 C. The genomic average nucleotide identity (ANI) shows it is closely related to V. diabolicus (ANI: 88.6%). Its genome contains 5,236,997- bp with 44.8% GC content, 3,710 protein-coding sequences, 96 RNA, 9 PHB genes functionally related to PHB metabolic pathways, and several genes linked to competing and colonizing abilities. CONCLUSIONS: This culturable PHB-accumulating Vibrio strain shows high genomic and phenotypic variability. It may be used as a natural pathogen biocontrol in the marine hatchery and as a potential cell factory for PHB production.

Actividad antitumoral de biopolímeros aislados de Vibrio sp. en cáncer de mama inducido en ratas / Antitumor activity of vibrio sp. isolated biopolymers in induced breast cancer in rats

RESUMEN Objetivo: Evaluar la actividad antitumoral del extracto crudo de biopolímeros aislados de la bacteria marina Vibrio sp. en cáncer de mama inducido por N-Methyl-N-nitrosourea (MNU) en ratas. Materiales y métodos: Se cultivó la bacteria marina Vibrio sp. durante siete días, luego se filtró, precipitó y concentró el sobrenadante crudo. Se administró una dosis única de MNU 50 mg/kg a 39 ratas Holtzman y fueron tratadas diariamente durante nueve semanas por vía oral: G1 (n=13): suero fisiológico 0,1 mL/100g; G2 (n=13): extracto crudo de biopolímeros de Vibrio sp. 20 mg/kg; G3 (n=13): tamoxifeno 100 mg/kg. El G4 (n=11) solo recibió suero fisiológico 0,1 mL/100g. Se valoró semanalmente el peso corporal y la aparición de tumores mamarios identificados mediante palpación; así como el examen histopatológico al final del tratamiento. Resultados: El 77% de las ratas del grupo G1 desarrollaron tumores a partir de la séptima semana en un promedio de 2,2 tumores por cada animal; en contraste al grupo tratado con el extracto crudo de biopolímeros y tamoxifeno; donde solo una rata (8%) en cada grupo desarrolló tumores y posterior a la semana nueve de la inducción (p=0,001). Los resultados histopatológicos sostienen que todos los tumores extirpados corresponden a adenocarcinoma ductal de mama con distintos patrones: sólido, papilar y quístico. Asimismo, se evidenciaron focos necróticos en el 30% de los tumores del grupo G1. Conclusión: El extracto crudo de biopolímeros aislados de Vibrio sp. presentan efecto antitumoral en cáncer de mama inducido en ratas.

ABSTRACT Objective: To evaluate the antitumor activity of the raw extract from biopolymers isolated from the Vibrio sp. marine bacteria in breast cancer induced by N-Methyl-N-nitrosourea (MNU) in rats. Materials and methods: The Vibrio sp. marine bacteria was cultured for seven days, then the raw supernatant was filtered, precipitated and concentrated. MNU was administered in a single dose of 50 mg/kg to 39 Holtzman rats and were daily treated for 9 weeks orally: G1 (n = 13): 0.1 mL/100 g of saline solution; G2 (n = 13): 20 mg/kg of raw extract from Vibrio sp. biopolymers; G3 (n = 13): 100 mg/kg of tamoxifen; G4 (n = 11) received no MNU and only 0.1 mL/100 g of saline solution. Body weight and the appearance of breast tumors identified by palpation were assessed weekly, as well as histopathological examination at the end of treatment. Results: Seventy-seven percent of the rats in the G1 group developed tumors from week 7 onwards in an average of 2.2 tumors per animal; in contrast to the group treated with the raw biopolymer extract and tamoxifen; where only one rat (8%) in each group developed tumors after week nine of induction (p = 0.001). The histopathological results support that all the removed tumors correspond to breast ductal adenocarcinoma with different patterns: solid, papillary and cystic. Likewise, necrotic foci were evidenced in 30% of the tumors of the G1 group. Conclusion: The raw extract of biopolymers isolated from Vibrio sp. present antitumor effect in breast cancer induced in rats.

Hemolytic and urease activities in vibrios isolated from fresh and frozen oysters

INTRODUCTION: The present study aimed to survey the Vibrio microbiota of oysters (Crassostrea rhizophorae) obtained from restaurants in Fortaleza, State of Ceará, Brazil, and to identify virulence factors. METHODS: The isolated vibrios were submitted to biochemical identification and were tested for hemolytic and urease activities. RESULTS: The isolated strains belonged to 13 species, with predominance of Vibrio mimicus. Of the strain isolates only from fresh samples, 20.5% and 2.8% showed hemolytic and urease activities, respectively. CONCLUSIONS: The findings support the little-publicized claim that Vibrio species other than V. parahaemolyticus and V. vulnificus can represent a health risk to public health.

A simplified procedure for rapid screening of vibrios for cholera toxin production.

Conventional methods for the detection of cholera toxin (CT) production by vibrios are not readily available to most laboratories. A modification is described here of a simplified method standardised earlier and based on the degradation of nicotinamide adenine dinucleotide (NAD) by CT; this is simple and can be carried out in small laboratories also. It is also easy to perform, and gives reproducible results.

An epidemic of tetrodotoxin poisoning following ingestion of the horseshoe crab Carcinoscorpius rotundicauda.

At certain seasons of the year in Thailand, the horseshoe crab Carcinoscorpius rotundicauda may be toxic to human and fatal poisoning occasionally occur. Tetrodotoxin (TTX) and its derivatives were major toxins in the toxic eggs of the horseshoe crab. An epidemic of poisoning by eating toxic eggs of the horseshoe crab affected 71 persons in Chon Buri which located in the eastern coast of Thailand. Patients generally presented with neurologic symptoms such as paresthesia, vertigo, weakness, respiratory paralysis, altered consciousness with unreactive dilated pupils in addition to gastrointestinal symptoms such as nausea and vomiting. Nineteen patients required artificial ventilation and there were two deaths. This is the first large outbreak of tetrodotoxin poisoning recognized in Thailand.