Isolation and Pathogenic Characterization of Vibrio bivalvicida Associated With a Massive Larval Mortality Event in a Commercial Hatchery of Scallop Argopecten purpuratus in Chile

The VPAP30 strain was isolated as the highly predominant bacteria from an episode of massive larval mortality occurring in a commercial culture of the Chilean scallop Argopecten purpuratus. The main aims of this study were, to characterize and identify the pathogenic strain using biochemical and molecular methods, to demonstrate its pathogenic activity on scallop larvae, to characterize its pathogenic properties and to describe the chronology of the pathology. The pathogenic strain was identified as Vibrio bivalvicida based on its phenotypic properties, the multilocus sequence analysis (MLSA) of eight housekeeping genes (ftsZ, gapA, gyrB, mreB, pyrH, recA, rpoA, and topA) and different in silico genome-to-genome comparisons. When triplicate cultures of healthy 10 days old scallop larvae were challenged with 1 × 105 colony forming units (CFU) mL-1 of the VPAP30 strain, percentages of larval survival of 78.9 ± 3.3%, 34.3 ± 4.9%, and 0% were observed at 12, 2,4 and 36 h, respectively, whereas uninfected larval cultures showed survival rates of 97.4 ± 1.2% after of 48 h. Clinical symptoms exhibited by the scallop larvae infected with the VPAP30 strain include the accumulation of bacteria around the scallop larvae, velum disruption and necrosis of digestive gland. The 50% lethal dose (LD50) of VPAP30 strain at 24 and 48 h was 1.3 × 104 and 1.2 × 103 CFU mL-1, respectively. The invasive pathogenic activity of the VPAP30 strain was investigated with staining of the bacterial pathogen with 5-DTAF and analyzing bacterial invasion using epifluorescence, and a complete bacterial dissemination inside the larvae at 24 h post-infection was observed. When scallop larvae were inoculated with cell-free extracellular products (ECPs) of VPAP30, the larval survival rate was 59.5 ± 1.7%, significantly (P < 0.001) lower than the control group (97.4 ± 1.2%) whereas larvae treated with heat-treated ECPs exhibited a survival rate of 61.6 ± 1.8% after 48 h of exposure. V. bivalvicida VPAP30 exhibits high pathogenic activity on scallop larvae, mediated both by bacterial invasion and the production of toxigenic heat-stable compounds. This report constitutes the first isolation of V. bivalvicida out of Europe and extends the host range of this species, having demonstrated its pathogenic activity on the Chilean scallop larvae (A. purpuratus). These results supporting the pathogenic potential of V. bivalvicida to kill the larvae of a broad range of bivalve species reared in hatcheries located in the Atlantic and the Pacific coasts.This study was financially supported by the Science and Technology National Council (CONICYT) of Chile by the Postdoctoral Project Grant No. 3150395 and FONDECYT grant No. 1140734 and FONDEF ID16I10291S

Efecto de Lactobacillus delbrueckii sobre las propiedades texturales de geles binarios de goma gelana

El objetivo del presente trabajo fue evaluar el efecto de la adición de una bacteria probiótica sobre las propiedades texturales de geles comestibles elaborados a base de goma gelana. Para la elaboración de la biopelículas se utilizó un diseño de mezclas simple así: gelana de alto acilo (GAA), gelana de bajo acilo (GBA) y sus mezclas  25GAA/75GBA, 50GAA/50GBA, 75GAA/25GBA, con adición de Lactobacillus delbrueckii. Posteriormente se determinaron las propiedades texturales. Los resultados mostraron que ninguna de las propiedades texturales (dureza, adhesividad, cohesividad, elasticidad) resultan afectadas por la adición de la bacteria probiótica. Sin embargo, todas las formulaciones presentaron características texturales apropiadas para el crecimiento de la bacteria probiótica durante su almacenamiento. Por consiguiente, los geles con adición de bacterias probióticas pueden ser aplicados a una gran variedad de productos alimenticios para incrementar su opción de consumo

DESARROLLO Y VALIDACIÓN DE UN MODELO MATEMÁTICO PARA DESCRIBIR EL CRECIMIENTO DE LACTOBACILLUS ACIDOPHILUS MICROENCAPSULADO EN UN SISTEMA BINARIO COMPUESTO POR GOMA GELANA

El objetivo del presente trabajo fue desarrollar y validar un modelo matemático que predice el crecimiento de Lactobaciilus acidophilus microencapsulado en un sistema gelificante binario compuesto por goma gelana de alto y bajo acilo.  Las velocidades de crecimiento de L. acidophilus fue extraída de datos experimentales llevado a cabo en el grupo de investigación en Biotecnología, Alimentos y Educación (GIBAE) perteneciente a la Universidad de Cartagena – Colombia. Los datos extraídos del crecimiento fueron usados para desarrollar un modelo relacionando la velocidad de crecimiento de L. acidophilus microencapsulado. La ecuación de Ratkowsky fue utilizada para modelar los datos. Finalmente la exactitud de los factores propuesto por Baranyi y col, (1999) fue usado para analizar el desarrollo del modelo. Los datos experimentales para el crecimiento de L. acidophilus mostraron una discrepancia con las predicciones cercanas al 7.2 % y un bias de 5.2%. El modelo desarrollado puede ser utilizado para determinar el efecto de las concentraciones iniciales de la bacteria y la temperatura en los procesos de optimización durante  la elaboración de alimentos funcionales.

Natural Products for Salmonellosis: Last Decade Research

Salmonellosis is a disease of great relevance in terms of public health given the economic and social impact that causes both in developing and highly industrialized countries. Due to its transmission mechanism, it affects hundreds or thousands of people every year and is considered an acute disease of worldwide distribution. Causative agent of salmonellosis is salmonella specie which are small gram-negative bacilli and facultative intracellular pathogen of the Enterobacteriaceae family. Multidrug resistance is reported more frequently in strains of salmonella, raising the necessity of new strategies to combat its spread and to treat the disease. Natural products (NPs) derived from traditional medicine knowledge have become an important resource to this end. In this chapter, we present a summary of information published from 2010 to 2020, as a sample of the potentiality of NPs as agents for Salmonellosis. This search was not exhaustive, rather, we aim to obtain a random sample of information using the simplest terms on the matter of natural products for salmonellosis, hopefully, as a reference source for interested researchers

Three-dimensional spectroscopy of local luminous compact blue galaxies: kinematic maps of a sample of 22 objects

We use three-dimensional optical spectroscopy observations of a sample of 22 local luminous compact blue galaxies (LCBGs) to create kinematic maps. By means of these, we classify the kinematics of these galaxies into three different classes: rotating disc (RD), perturbed rotation (PR) and complex kinematics (CK). We find 48 per cent are RDs, 28 per cent are PRs and 24 per cent are CKs. RDs show rotational velocities that range between similar to 50 and similar to 200 km s(-1), and dynamical masses that range between similar to 1 x 10(9) and similar to 3 x 10(10) M(circle dot). We also address the following two fundamental questions through the study of the kinematic maps: (i) What processes are triggering the current starburst in LCBGs? We search our maps of the galaxy velocity fields for signatures of recent interactions and close companions that may be responsible for the enhanced star formation in our sample. We find that 5 per cent of objects show evidence of a recent major merger, 10 per cent of a minor merger and 45 per cent of a companion. This argues in favour of ongoing interactions with close companions as a mechanism for the enhanced star formation activity in these galaxies. (ii) What processes may eventually quench the current starbust in LCBGs? Velocity and velocity width maps, together with emission line ratio maps, can reveal signatures of active galactic nuclei (AGNs) activity or supernova (SN)-driven galactic winds that could halt the current burst. We find only 5 per cent of objects with clear evidence of AGN activity and 27 per cent with kinematics consistent with SN-driven galactic winds. Therefore, a different mechanism may be responsible for quenching the star formation in LCBGs. Finally, from our analysis, we find that the velocity widths of RDs, rather than accounting exclusively for the rotational nature of these objects, may account as well for other kinematic components and may not be good tracers of their dynamical masses

Comparison of Two Core Biopsy Techniques Before and After Laparoscopic Cryoablation of Small Renal Cortical Neoplasms

A pre-ablation standard biopsy technique resulted in the most accurate pathologic diagnosis for patients undergoing cryoablation for renal cortical neoplasms

Direct Polyphenol Attachment on the Surfaces of Magnetite Nanoparticles, Using Vitis vinifera, Vaccinium corymbosum, or Punica granatum

This study presents an alternative approach to directly synthesizing magnetite nanoparticles (MNPs) in the presence of Vitis vinifera, Vaccinium corymbosum, and Punica granatum derived from natural sources (grapes, blueberries, and pomegranates, respectively). A modified co-precipitation method that combines phytochemical techniques was developed to produce semispherical MNPs that range in size from 7.7 to 8.8 nm and are coated with a ~1.5 nm thick layer of polyphenols. The observed structure, composition, and surface properties of the MNPs@polyphenols demonstrated the dual functionality of the phenolic groups as both reducing agents and capping molecules that are bonding with Fe ions on the surfaces of the MNPs via –OH groups. Magnetic force microscopy images revealed the uniaxial orientation of single magnetic domains (SMDs) associated with the inverse spinel structure of the magnetite (Fe3O4). The samples’ inductive heating (H0 = 28.9 kA/m, f = 764 kHz), measured via the specific loss power (SLP) of the samples, yielded values of up to 187.2 W/g and showed the influence of the average particle size. A cell viability assessment was conducted via the MTT and NRu tests to estimate the metabolic and lysosomal activities of the MNPs@polyphenols in K562 (chronic myelogenous leukemia, ATCC) cells