The probiotic Shewanella putrefaciens PDP11 target virulence factors by modulating quorum sensing inhibition

Bacteria communicate with each other by producing signal molecules and regulating the production of virulence factors that have importance in pathogenicity. Quorum sensing (QS) is a bacterial communication mechanism based on the perception of population density and secretion of determining signal molecules called autoinducers (AI) such as the case of Acylhomoserine lactones (AHLs). AHLs-mediated QS processes seem to be common in the marine environment and among marine pathogenic bacteria, which pathogenesis could be mitigated by probiotics, among others. Probiotics are defined as live microbial cells that confer health benefits to the host and some of their mechanisms include the production of antagonistic compounds that are inhibitory toward pathogens. In this sense, Shewanella putrefaciens Pdp11, a strain described as a probiotic for use in aquaculture, has been analysed to mediate QS processes by quorum-quenching assays using synthetic AHLs. The enzymatic activity is estimated at around 80% and 30% for C8- and C10-HSL, respectively, while the rest of AHLs tested were not degraded by the Pdp11 strain. It would be an interesting feature of the probiotic Pdp11 strain since these AHLs are related to facilitating microbial adhesion by promoting biofilm formation among other virulence factors related to pathogens. On the other hand, a distinctive feature of AHL inactivated by lactonase is that it can be reactivated by acid treatment. In this way, little C8-AHL was recovered when it is extracted to pH2, which indicates the enzyme activity is not derived from the hydrolysis of the lactone ring derived from the action of lactonases, suggesting the enzyme activity in Pdp11 could be an AHL-acylase. The potential QQ activity of Pdp11 was unknown so, these preliminary studies led to a further as another promising probiotic QQ tool for aquaculture

Insights into the fecal microbiota of captive Iberian lynx (Lynx pardinus)

The Iberian lynx (Lynx pardinus) is an endangered species restricted to several areas of Spain and Portugal. Its low genetic diversity likely provokes immune depression and high susceptibility to infectious diseases. The intestinal microbiota is closely related to host health and nutrition. In order to contribute to the knowledge of the Iberian lynx intestinal microbiota, fecal microbiota of captive specimens from two breeding centers (“La Olivilla” and “El Acebuche”), located in Southern Spain, were studied by Denaturing Gradient Gel Electrophoresis (DGGE). Results grouped microbiota in two main clusters (I and III) which included DGGE patterns of 19 out of 36 specimens, cluster I being the most frequent in “La Olivilla” (50%) and cluster III in “El Acebuche” (55.55 %) specimens. Bacteroidetes, Firmicutes and Proteobacteria phyla were identified. Segregation of clusters I and III was attributed to different microorganism presence (Pseudomonas koreensis, Pseudomonas migulae, Carnobacterium sp., Arthrobacter, Robinsoniella peorensis and Ornithinibacillus sp.) and ability to use different carbon sources. Biolog EcoPlates® results indicate high functional diversity of fecal microbiota, it being higher in cluster III. The great impact of intestinal microbiota on host health supports the importance of its microbial composition understanding. This study is the first report of captive Iberian lynx fecal microbiota composition. [Int Microbiol 20(1): 31-41 (2017)]Keywords: Iberian lynx (Lynx pardinus) · fecal microbiota · biodiversit

Adsorption of salmonella in clay minerals and clay-based materials

A series of clay minerals and clay-based materials have been tested to eliminate one of the most dangerous bacteria we can find in the water: Salmonella. It has been proven that the use of clays and their PCH materials can be a suitable method for removing Salmonella from water. The results of this initial study show that all the materials analyzed have great salmonella adsorption capacities ranging from the lowest value observed in the mont-PCH sample (0.29 × 1010 CFU g−1 ) to the highest value observed in the natural palygorskite sample (1.52 × 1010 CFU g−1 ). Macroporosity, accessible external surface area, and the presence of silanol groups in the external surface of the particles appears to be the controlling factors for Salmonella adsorption capacity while it seems that the structural characteristics of the clay minerals and their respective PCH does not affect the adsorption capacityThe authors wish to thank the project BIA2017-82391-R for the financial suppor

Potential postbiotic activities of extracellular products of probiotic bacteria from gilthead seabream gastrointestinal tract

Probiotics have been established as a potential tool for improving gut health and environmental quality in aquaculture. However, recent evidence suggests that bacterial viability is not necessary to attain the beneficial-promoting effects. In this way, postbiotics have emerged providing a potential opportunity in the field of functional foods. They are soluble factors resulting from the metabolic activity of a probiotic or any released molecule, including short-chain fatty acids, enzymes, extracellular products, etc. that can have interesting properties inducing biological responses on health similar to probiotics while avoiding the administration of live microorganisms. Interestingly, its production can be affected by different factors such as the components of the culture media among others. Information on this type of postbiotic activities is very scarce, especially in the case of aquaculture, so the evaluation of the nutraceutical use of postbiotics to improve health management in fish and other cultivated aquatic organisms is an emerging area of research in aquaculture. In a previous work, we characterized four potential probiotics that were isolated from the gastrointestinal tract of Sparus aurata specimens fed with a diet containing a blend of microalgae. This diet involves a selection pressure on the intestinal microbiota of the fish that will be used to achieve enrichment in bacteria with a set of extracellular enzymatic activities capable of metabolizing and mobilizing the components of the diet enriched with microalgae. Here, we investigate the postbiotic potential of the extracellular products (ECPs) obtained from the four candidate probiotics grown on different microalgae-supplemented medium, and evaluate its enzymatic and antibacterial activity, and its cytotoxicity against the SAF-1 cell line. Our objective is to select different ECPs with a variety of activities that help the digestive process of seabream, with the aim to be included in aquafeeds.This work was funded by Junta de Andalucía (grant no. P20_00085) and co-financed by FEDER funds

Inactivation of simulated aquaculture stream bacteria at low temperature using advanced UVA- and solar-based oxidation methods

In this work the effect of water temperature (6 +/- 1 degrees C and 22 +/- 1 degrees C) on inactivation of bacteria (104 -106 CFU mL-1; Pseudomonas spp., Aeromonas spp. and Enterobacter spp.) in simulated aquaculture streams (SAS) using UVA based advanced oxidation processes (AOP) (H2O2-assisted UVA; photocatalysis; H2O2-assisted photocatalysis) and solar driven AOPs (H2O2-assisted solar disinfection, SODIS) was studied. Efficiency at 22 degrees C in terms of inactivation rate was higher using H2O2-assisted photocatalysis (H2O2/UVA-TiO2/polysiloxane) > H2O2-assisted UVA disinfection (UVA/H2O2 - 10 mg L-1) > photocatalysis (UVA-TiO2/polysiloxane) > UVA disinfection. At low temperature (6 degrees C) the inactivation rate increased with SODIS/H2O2 > SODIS > H2O2assisted UVA disinfection (UVA/H2O2 - 10 mg L-1) > H2O2-assisted photocatalysis (H2O2/UVA-TiO2/polysiloxane) > photocatalysis (UVA-TiO2/polysiloxane). The main results indicate that the inactivation rates increased when hydrogen peroxide (10 mg L-1) was used during H2O2-assisted UVA disinfection and photocatalysis. In addition, exposure of SAS to hydrogen peroxide for 24 h (in absence of light) at room temperature decreased the subsequent exposure UVA irradiation dose by almost four times. Drastic increase of inactivation rate was observed at low water temperature (6 +/- 1 degrees C) when UVA- and solarbased AOPs were employed compared to 22 +/- 1 degrees C. The treatment with SODIS proved to be more effective in Finland than in Spain. The effect of the low temperature (6 +/- 1 degrees C) was proposed as a critical factor during UVA disinfection (UVA/H2O2 and photocatalysis) that can increase the disinfection rate constant (kmax) by 1.3-5.2 times, leading to a reduction of the treatment costs ( euro m-3) by 1.3-3.3 times. The mechanism of observed enhanced disinfection at low water temperature (6 +/- 1 degrees C) when natural solar light and UVA are employed as irradiation sources for UVA/H2O2 and photocatalytic bacteria inactivation was proposed. No regrowth was observed in case of H2O2-assisted AOPs.This work was supported by a national research project (SUNRAS PROJECT, Project AGL2016-80507-R) funded by Ministerio de Economia y Competitividad (Plan Nacional de I + D + i (2013-2016). The research was also supported by a PIF contract (UCA/REC01VI/2017) funded by Vicerrectorado de Investigacion of Universidad de Cadiz. D. Sc. Juan Jose Rueda-Marquez is grateful for financial support from Academy of Finland within the project '' Combination of Advanced Oxidation Processes and Photobiotreatment for Sustainable Resource Recovery and Wastewater Reuse'' (application number 322339). T. Homola acknowledges financial support by Czech Science Foundation project 19-14770Y and project LM2018097 funded by the Ministry of Education, Youth and Sports of the Czech Republic. Documen

Relación entre la microbiota intestinal y la composición de ácidos grasos tras la administración del probiótico Shewanella putrefaciens Pdp11 bioencapsulado en Artemia en ejemplares larvarios de S. senegalensis

Estudios previos confirmaron que un pulso corto (10-30 dpe) del probiótico S. putrefaciens Pdp11 (2.5x10 7 cfu mL-1) bioencapsulado en Artemia y administrado a ejemplares larvarios de S. senegalensis incrementaron significativamente los niveles de lípidos totales y de ciertos ácidos grasos de los ejemplares. Dicha dieta suplementada produjo además cambios importantes en las especies microbianas intestinales de dichos organismos. La realización de un análisis de componentes principales (ACP) confirmó el efecto de la dieta probiótica en los ejemplares, sobre su microbiota y sobre a los niveles de ácidos grasos analizados

Use of in vivo-induced antigen technology to identify bacterial genes expressed during solea senegalensis infection with Photobacterium damselae subsp. piscicida

The marine fish pathogen Photobacterium damselae subsp. piscicida (Phdp) is responsible for important outbreaks affecting several fish species including flatfish Solea senegalensis. The aim of this work was to identify in vivo-induced expressed immunogenic proteins using pooled sera from fish that have experienced photobacteriosis. In vivo induced immunogenic proteins included inosine-5'-monophosphate dehydrogenase (Impdh) and alkyl hydroperoxide reductase (AhpC), two proteins involved in peptide synthesis: serine hydroxymethyl transferase (Shmt) and alanyl-tRNA synthetase (AlaRS) and the non-ribosomal peptide synthetase involved in the synthesis of the siderophore piscibactin (Irp2)

Shewanella putrefaciens Fish pathogenic strains contain plasmids that are absent in the probiotic strain s. Putrefaciens pdp11

Probiotics are live microorganisms that confer a health benefit to the host when administered in adequate amounts. Shewanella putrefaciens Pdp11 has been described as a probiotic for farmed fish species such as Solea senegalensis and Sparus aurata. In contrast, other strains of S. putrefaciens have been described as pathogenic for other cultured fish damage of the mouth, extensive skin discoloration, exophthalmia, ascites and bad odour. The S. putrefaciens group was recovered from freshwater samples taken at the L′Albufera system, along autumn– winter 2015. Its counts significantly increased in freshwater parallel to hypoxia and temperature rising. Shewanellae strains were identified as S. putrefaciens and S. xiamenensis by 16S rRNA gene sequencing. These isolates recovered from sick eels or freshwater were virulent for European eel by IP challenge (LD50 106 CFU g−1 body weight. The plasmids plays an important role in the genes transfer and insertion then there can been implicated in antibiotics resistance, degradative pathway and pathogenicity characteristics. The genetic variation conducted by plasmid could induce an impact in probiotic proprieties. In this research, we searched the present or absent of plasmids in pathogenic and probiotic strains of S. putrefaciens. As well as, this plasmids implication in development of virulence factors. The probiotic strain S. putrefaciens Pdp11 did not present plasmid, which was only found in two of the five pathogenic strains. The results allowed us to discard the probiotic Pdp11 could present a pathogenic characteristic as the TA type II system as a virulence factor and its self-regulating characteristics, which may be behind its probiotic nature, making the Pdp11 strain unique in comparison to other S. putrefaciens strains

Procedimiento de preparación, conservación, y uso en peces, del probiótico SHEWANELLA PUTREFACIENS PDP 11 para el control de enfermedades y la mejora en el crecimiento

Número de solicitud 201100385Procedimiento de preparación, conservación, y uso en peces, del probiótico Shewanella putresfaciens Pdp11 para el control de enfermedades y la mejora en el crecimiento. Preferentemente, el probiótico, compuesto por células enteras de la cepa Pdp11, se cultiva en TSAs durante 24 h a 22ºC. La preparación de una suspensión del probiótico, preferentemente sin proceso previo de liofilización o de inactivación física o química, se realiza mediante su incorporación en una matriz de alginato, preferentemente alginato sádico al 0,5%. La suspensión preparada se puede conservar sin pérdida significativa de viabilidad durante 20 - 30 días a 4ºC. Los productos alimenticios para peces son preparados mediante la adición en agitación de la suspensión de probiótico y, adicionalmente, CaCl2 50 mM, preferentemente mediante atomización.Universidad de Málaga (50%). Universidad de Almería (50%

Preparado de bacterias probióticas para su administración oral a peces cultivados basado en la encapsulación en hidrogeles de alginato

Número de solicitud: 201100469La invención consiste en un preparado para la administración oral del probiótico Shewanella PDP11 a peces. El preparado se caracteriza por contener células bacterianas viables de la cepa CECT 7627 encapsuladas en un hidrogel basado en alginato cálcico en forma de partículas esféricas de morfología uniforme y tamaño modificable para adaptarse a peces de distinto tamaño. Las cápsulas contienen aditivos organolépticos y/o nutricionales que actúan como atrayentes para los animales. El preparado mantiene viables a las bacterias durante periodos prolongados, es estable en medios acuáticos, y soporta el paso por el tubo digestivo de los peces, sobre los que ejerce efectos biológicos favorables. Su administración por vía oral es independiente del alimento habitual, evitando así la inactivación del microorganismo durante la fabricación del pienso.Universidad de Almerí