Eficacia de un desinfectante sobre Vibrio ordalii, Vibrio anguillarum, Francisella sp. y Virus de la Necrosis Pancreática Infecciosa (IPNV), patógenos de salmón del Atlántico (Salmo salar) cultivado en Chile

Indexación: ScieloRESUMEN En el presente trabajo se evaluó la eficacia in vitro del desinfectante Duplalim®, una combinación sinérgica de glutaraldehído y sales de amonio cuaternario de cuarta generación, contra 4 patógenos de peces prevalentes de la salmonicultura chilena. Los resultados muestran que todas las concentraciones ensayadas (diluciones entre 1:200 a 1:400) fueron eficaces sobre los aislados de Vibrio ordalii y Vibrio anguillarum post-30 s de exposición, detectando niveles de reducción igual a 1.8 x 106 UFC/ml. Concentraciones superiores de Duplalim® (dilución 1:50) y un tiempo de exposición no menor a 5 min. Fueron necesarios para eliminar completamente al patógeno intracelular Francisella sp. Cuando el desinfectante fue ensayado contra el Virus de la necrosis Pancreática infecciosa (IPNV), se detectó que la dilución 1:400 tiene un efecto significativo después de 2 minutos sin importar los títulos de IPNV testeados (mayor concentración evaluada 107.6 TCID50/ml). Duplalim® se evaluó en condiciones masivas contra los miembros de la familia Vibrionaceae. En comparación a los controles (sin adición desinfectante), la dilución 1:400 de Duplalim® eliminó completamente V. ordalii y V. anguillarum después de 15 minutos de tratamiento, tanto en el agua de cultivo como en la superficie de mallas usadas en el cultivo del salmón. Así, el análisis microbiológico del agua de los controles mostró concentraciones de 1.4 ± 0.3 × 106 UFC/ml, mientras en el caso de las mallas 7.6 ± 3.2 × 105 UFC/ml1. En resumen, los antecedentes obtenidos indican que el uso del desinfectante Duplalim® es efectivo contra V. ordalii, V. anguillarum y IPNV en bajas concentraciones y cortos periodos de exposición (dilución 1:400 por 15 min.), mientras que para el patógeno intracelular se requiere una concentración mayor. Palabras clave: desinfectante, patógenos de peces, salmón del atlántico. SUMMARY The efficacy of the disinfectant Duplalim®, a synergistic blend of superquats and glutaraldehyde, was analysed in vitro against 4 fish pathogens. All concentrations tested (1:200 to 1:400 dilutions) were efficacious on killing Vibrio ordalii and Vibrio anguillarum in seawater after 30 s, being the level of reduction equal to 1.8 x 106 CFU/ml. Higher concentration of Duplalim® (1:50 dilutions) and time of exposure (at least 5 min) is needed to kill completely Francisella sp, an intracellular freshwater pathogen. When Infectious Pancreatic Necrosis Virus (IPNV) was treated with 1:400 disinfectant dilution, this concentration had a significant effect after 2 minutes, regardless of the IPNV titres employed (concentration greater than 107.6 TCID50/ml). Duplalim® was tested in large scale against Vibrionaceae members. In comparison to the controls (without the disinfectant), 1:400 dilutions of Duplalim® totally killed V. ordalii and V. anguillarum in seawater as well as on the surface of the fishing net (used in the cages of cultured salmon) after 15 min. Cultivable bacteria remained constant in the buckets without the disinfectant (1.4 ± 0.3 × 106 CFU/ml), regardless of the period sampled. In the case of the adherence on the fishing net, bacteria not exposed to the disinfectant were detected at a concentration of 7.6 ± 3.2 × 105 CFU/ml. These data indicate that the use of Duplalim® against V. ordalii, V. anguillarum and IPNV is effective in low concentration and short time of exposure (15 min at a concentration of 1:400 dilutions), while the intracellular pathogen requires higher concentration. Key words: disinfectant, Chilean fish pathogens, Atlantic salmon

Comparative genomic analysis of two Chilean Renibacterium salmoninarum isolates and the type strain ATCC 33209T

Indexación: Scopus.Two previously characterized Chilean isolates (H-2 and DJ2R), obtained from cage-cultured Atlantic salmon with clinical signs of bacterial kidney disease in southern Chile, were used (Bethke et al. 2016, 2017). The bacteria were routinely cultured in KDM-2 agar for 15–20 days at 15°C. For sequencing, genomic DNA of the two isolates was extracted using the InstaGene Purification Matrix (Bio-Rad) according to manufacturer instructions. The DJ2R genome was sequenced using an Illumina MiSeq platform with 2 ⨯ 250 paired-end reads by the AUSTRAL-omics Institute, hosted by the Universidad Austral de Chile (Valdivia, Chile). Using the same technology and parameters, H-2 genomic DNA was sequenced by the Central Support Service for Experimental Research (SCSIE, Spanish acronym) at the University of Valencia (Valencia, Spain).This work was supported by funding of the Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile) [Grant Numbers FONDAP No. 15110027 and FONDECYT No. 1150695]. J.B. also acknowledges support received by CONICYT [Doctoral Scholarship No. 21140421].Renibacterium salmoninarum, a slow-growing facultative intracellular pathogen belonging to the high C+G content Actinobacteria phylum, is the causative agent of bacterial kidney disease, a progressive granulomatous infection affecting salmonids worldwide. This Gram-positive bacterium has existed in the Chilean salmonid industry for >30 years, but little or no information is available regarding the virulence mechanisms and genomic characteristics of Chilean isolates. In this study, the genomes of two Chilean isolates (H-2 and DJ2R)were sequenced, and a search was conducted for genes and proteins involved in virulence and pathogenicity, andwecompare with the type strain ATCC 33209T genome. The genome sizes of H-2 and DJ2R are 3,155,332 bp and 3,155,228 bp, respectively. They genomes presented six ribosomal RNA, 46 transcription RNA, and 25 noncodingRNA, and both had the same 56.27% G+C content described for the type strain ATCC 33209 T. A total of 3,522 and 3,527 coding sequences were found for H-2 and DJ2R, respectively. Meanwhile, the ATCC 33209T type strain had 3,519 coding sequences. The in silico genome analysis revealed a genes related to tricarboxylic acid cycle, glycolysis, iron transport and others metabolic pathway. Also, the data indicated that R salmoninarum may have a variety of possible virulence-factor and antibiotic-resistance strategies. Interestingly, many of genes had high identities with Mycobacterium species, a known pathogenic Actin obacteria bacterium. In summary, this study provides the first insights into and initial steps towards understanding the molecular basis of antibiotic resistance, virulence mechanisms and host/environment adaptation in twoChilean R. salmoninarum isolates that contain proteins of which were similar to those of Mycobacterium. Furthermore, important information is presented that could facilitate the development of preventive and treatment measures against R. salmoninarum in Chile and worldwide. © The Author(s) 2018.https://academic.oup.com/gbe/article/10/7/1816/504777

Stress tolerance-related genetic traits of fish pathogen Flavobacterium psychrophilum in a mature biofilm

Indexación: Scopus.Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout fry syndrome, and hence this bacterium is placed among the most important salmonid pathogens in the freshwater aquaculture industry. Since bacteria in biofilms differ substantially from free-living counterparts, this study sought to find the main differences in gene expression between sessile and planktonic states of F. psychrophilum LM-02-Fp and NCMB1947T, with focus on stress-related changes in gene expression occurring during biofilm formation. To this end, biofilm and planktonic samples were analyzed by RNA sequencing to detect differentially expressed candidate genes (DECGs) between the two growth states, and decreasing the effects of interstrain variation by considering only genes with log2-fold changes ≤ -2 and ≥ 2 at Padj-values = 0.001 as DECGs. Overall, 349 genes accounting for ~15% of total number of genes expressed in transcriptomes of F. psychrophilum LM-02-Fp and NCMB1947T (n = 2327) were DECGs between biofilm and planktonic states. Approximately 83 and 81% of all up- and down-regulated candidate genes in mature biofilms, respectively, were assigned to at least one gene ontology term; these were primarily associated with the molecular function term "catalytic activity." We detected a potential stress response in mature biofilms, characterized by a generalized down-regulation of DECGs with roles in the protein synthesis machinery (n = 63, primarily ribosomal proteins) and energy conservation (seven ATP synthase subunit genes), as well as an up-regulation of DECGs involved in DNA repair (ruvC, recO, phrB1, smf, and dnaQ) and oxidative stress response (cytochrome C peroxidase, probable peroxiredoxin, and a probable thioredoxin). These results support the idea of a strategic trade-offbetween growth-related processes and cell homeostasis to preserve biofilm structure and metabolic functioning. In addition, LDH-based cytotoxicity assays and an intraperitoneal challenge model for rainbow trout fry agreed with the transcriptomic evidence that the ability of F. psychrophilum to form biofilms could contribute to the virulence. Finally, the reported changes in gene expression, as induced by the plankton-to-biofilm transition, represent the first transcriptomic guideline to obtain insights into the F. psychrophilum biofilm lifestyle that could help understand the prevalence of this bacterium in aquaculture settings.https://www.frontiersin.org/articles/10.3389/fmicb.2018.00018/ful

Good Practice Guide for Managing IT Risk in Colombian Banking: Specification by Disciplines

In this paper, we describe the work, findings, study case and contributions made in the development of the specification of the “Guía de buenas prácticas de gestión de riesgo de TI en el sector bancario colombiano”1. We present how doing the specification of the most important step of the guide, makes it a strong tool for managing IT risk in the Colombian banking sector. This was achieved by reviewing some of the most relevant theories in IT risk management, developing new models that exploit their best attributes, and presenting them from a business point of view. Finally, we present the results obtained from validating the new constructed models in our study case: the cheque clearing process of “Banco de la República”2; a core service in the organization that depends ninety percent on IT

Cuadro de mando integral (CMI) y el enfoque sistémico (ES) como herramientas para la generación de valor económico del capital humano en las organizaciones

En la era del conocimiento surgen nuevas necesidades relacionadas con la valuación de activos intangibles que no son reflejados en los estados financieros y que sin embargo dan valor a las entidades u organizaciones, por ello es necesario crear propuestas de valuación para esta clase de activos. Entre las razones que podemos mencionar para dar solución a esta problemática encontramos: a) Información transparente que provea de información útil a los accionistas para que puedan tomar decisiones racionales de inversión y crédito. b) Valor de la Organización Entender el crecimiento o decrecimiento del negocio en base a los activos específicos y a la generación de utilidades y flujo de efectivo futuro, c) Evaluación del Rendimiento de la Inversión Cuantificar los beneficios de inversiones, d) Planeación estratégica Entender los generadores de valor de la empresa, e) Control Administrativo Monitorear el valor del conocimiento, f) Programas de racionalización y mejora continua Reducir los centros de costos o áreas de soporte organizacional en base a las capacidades que agregan valor. Por lo que la investigación tiene como finalidad elaborar un modelo de evaluación económica que permita medir el impacto de la productividad intangible del capital humano en la generación de valor económico de una entidad, utilizando para ello el Cuadro de Mando Integral (CMI) y el Enfoque Sistémico (ES) que permitan la medición del capital humano a través de una metodología de evaluación de gestión empresarial

Avances en el conocimiento del patógeno de peces "Tenacibaculum maritimum", implicaciones en el diagnóstico y prevención de la enfermedad

En esta memoria hemos llevado a cabo la caracterización bioquímica, serológica y molecular de Tenacibaculum maritimum, agente causal de la tenacibaculosis o flexibacteriosis, enfermedad que causa importantes pérdidas en el cultivo de peces. Asimismo, determinamos la presencia de mecanismos de captación de hierro y los aspectos epizootiológicos de este microorganismo.In this work we conducted the biochemical, antigenical and molecular characterization of Tenacibaculum maritimum, the etiological agent of tenacibaculosis or flexibacteriosis. This disease constitutes one of the main problems in marine aquaculture, causing serious mortalities and hence severe economic losses. Likewise the presence of iron uptake mechanisms and the epizootiological aspects of this microorganism were also determined

Characterization and utilization of sawdust waste generated from advanced manufacture for its application as a thermal insulation in sustainable buildings using the blowing technique

[EN] The construction industry is vital for economic development, but it accounts for 40% of energy consumption and 45% of global greenhouse gas emissions. In this context, research has focused on reducing energy demand in homes, particularly through the development of insulation materials. Sawdust is a byproduct available annually in Chile in quantities exceeding 4.5 million tons. Therefore, the objective of this study was to characterize the physical and thermal properties of this waste to evaluate its use as a thermal insulation material. Stability and thermal conductivity tests, as well as density and moisture content measurements, were conducted on the sawdust. Additionally, to assess the functionality of this thermal insulator, the material was applied using the blowing technique in partitions, followed by physical tests. The results indicate that the proposed insulation material has thermal stability up to 270 degrees C. The thermal conductivity was comparable to conventional mineral wool and fiberglass (0.042 -0.048 [W/mK]). The density ranged from 123.77 to 198.15 [kg/m 3 ] depending on the filling time of the specimens but remained low compared to other organic materials. The moisture content was 11.31%, suitable for maintaining good thermal conductivity. This study concludes that sawdust is a viable alternative for thermal insulation, especially when applied through blowing. Its stability and thermal conductivity are comparable to conventional materials, while its thermal inertia is 200% higher than that of glass wool. Furthermore, the low moisture content suggests that there would be no proliferation of pathogens, making it a promising thermal insulator for sustainable construction development. Finally, it is mentioned that the material carbonizes within a limited time, leading to self -extinguishment of the flame.Rojas-Herrera, C.; Martínez-Soto, A.; Avendaño-Vera, C.; Cárdenas, JP. (2024). Characterization and utilization of sawdust waste generated from advanced manufacture for its application as a thermal insulation in sustainable buildings using the blowing technique. Journal of Building Engineering. 88. https://doi.org/10.1016/j.jobe.2024.1092178