Biofouling inhibition by Staphylococcus aureus extracts and their potential use for paints.

For the control of biofouling, some paints based on compounds that are toxic to marine organisms have been used. There is an intensive search for biodegradable solutions that are friendly to non-target organisms. Bacteria have been shown to be a source of compounds with antifouling potential. In this work, the antifouling activity of a strain of Staphylococcus aureus was evaluated. Extracts activity against biofilm-forming bacteria and the toxicity against Artemia franciscana were evaluated. The extracts were incorporated in a hard gel and a paint matrix, and they were exposed to the sea. In both the laboratory and field, we found that the compounds produced by S. aureus have antifouling activity. The non-toxicity of the tested extracts against Artemia franciscana nauplii suggests that the extracts obtained from S. aureus could have a low ecological impact over non-target organisms. Significant differences were found in the percentage of organisms cover in hard gels with extracts and control. After 90 days, important differences were also observed between the percentage of organisms cover of the paints that contained extracts and the control. Dichloromethane extract is the most effective for the inhibition or delay of the settlement of organisms For this reason, they could be used in matrices with different applications, such as in the shipping industry, aquaculture, or any other in which biofouling is a cause of inconvenience.

Marine bacteria associated with shallow hydrothermal systems in the Gulf of California with the capacity to produce biofilm inhibiting compounds.

Shallow hydrothermal systems are extreme environments. The sediments and fluids emitted from the vents present unusual physical and chemical conditions compared to other marine areas, which promotes unique biodiversity that has been of great interest for biotechnology for some years. In this work, a bioprospective study was carried out to evaluate the capacity of bacteria associated with shallow hydrothermal vents to produce biofilm-inhibiting compounds. Degradation assays of N-acyl homoserine lactone (AHL) autoinducers (C6HSL) involved in the quorum sensing process were carried out on 161 strains of bacteria isolated from three shallow hydrothermal systems located in Baja California Sur (BCS), Mexico. The biosensor Chromobacterium violaceum CV026 was used. Twenty-three strains showed activity, and organic extracts were obtained with ethyl acetate. The potential of the extracts to inhibit the formation of biofilms was tested against two human pathogenic strains (Pseudomonas aeruginosa PAO1 and Aeromonas caviae ScH3), a shrimp pathogen (Vibrio parahaemolyticus M8), and two marine strains identified as producing biofilms on submerged surfaces (Virgibacillus sp C29 and Vibrio alginolyticus C96). The results showed that Vibrio alginolyticus and Brevibacillus thermoruber, as well as some thermotolerant strains (mostly Bacillus), produce compounds that inhibit bacterial biofilms (B. licheniformis, B. paralicheniformis, B. firmus, B. oceanizedimenis, B. aerius and B. sonorensis).

Depth effect on the prokaryotic community assemblage associated with sponges from different rocky reefs.

Background: Sponge microbiomes are essential for the function and survival of their host and produce biologically active metabolites, therefore, they are ideal candidates for ecological, pharmacologic and clinical research. Next-generation sequencing (NGS) has revealed that many factors, including the environment and host, determine the composition and structure of these symbiotic communities but the controls of this variation are not well described. This study assessed the microbial communities associated with two marine sponges of the genera Aplysina (Nardo, 1834) and Ircinia (Nardo, 1833) in rocky reefs from Punta Arena de la Ventana (Gulf of California) and Pichilingue (La Paz Bay) in the coast of Baja California Sur, México to determine the relative importance of environment and host in structuring the microbiome of sponges. Methods: Specimens of Aplysina sp were collected by scuba diving at 10 m and 2 m; Ircinia sp samples were collected at 2 m. DNA of sponge-associated prokaryotes was extracted from 1 cm3 of tissue, purified and sent for 16S amplicon sequencing. Primer trimmed pair-ended microbial 16S rDNA gene sequences were merged using Ribosomal Database Project (RDP) Paired-end Reads Assembler. Chao1, Shannon and Simpson (alpha) biodiversity indices were estimated, as well permutational analysis of variance (PERMANOVA), and Bray-Curtis distances. Results: The most abundant phyla differed between hosts. Those phyla were: Proteobacteria, Acidobacteria, Cyanobacteria, Chloroflexi, Actinobacteria, Bacteroidetes, and Planctomycetes. In Ircinia sp the dominant phylum was Acidobacteria. Depth was the main factor influencing the microbial community, as analysis of similarities (ANOSIM) showed a significant difference between the microbial communities from different depths. Conclusion: Microbial diversity analysis showed that depth was more important than host in structuring the Aplysina sp and Ircinia sp microbiome. This observation contrast with previous reports that the sponge microbiome is highly host specific.

Biochemical characterization and in vitro biological activities of the epithelial cell extracts from Hypanus dipterurus spine.

Ocean organisms live in competitive environments that demand the production of poisons and toxins. In some cases, these substances have been used in the pharmaceutical industry for human disease treatments. Most fish poisons generally have potent cytolytic activity, probably through cardiovascular and neuromuscular effects. In the case of marine stingrays, the injuries made by their tail venom apparatus are caused by the mechanical penetration of their sting and a subsequent venom release. This study focused on the evaluation of substances with cytotoxic activity in the epithelium that covers the venom apparatus from the marine stingray Hypanus dipterurus. To demonstrate the above, the hemolytic, proteolytic and cytotoxic capacities of H. dipterurus epithelium substances were determined. Discs impregnated with epithelial extract were used on blood agar plates. The proteolytic activity was analyzed using casein as substrate and for gelatin the liquefaction activity test. To determine the cytotoxicity degree of the extracts, the proliferation and cell viability MTT bioassay was implemented on human cervical carcinoma cells (HeLa). The results showed that no hemolytic or proteolytic activity existed against casein associated with the epithelial extract, but gelatin hydrolysis and cytotoxic activity against the HeLa cell line were observed. This study concludes that the substances found in the epithelium covering the H. dipterurus stingray venom apparatus are a mixture of various proteins, among which, glycosylated anionic proteins represent a potential source of molecules with cytotoxic and hydrolytic activity.

Biosorption of Cadmium by Non-Toxic Extracellular Polymeric Substances (EPS) Synthesized by Bacteria from Marine Intertidal Biofilms.

Cadmium is a major heavy metal found in polluted aquatic environments, mainly derived from industrial production processes. We evaluated the biosorption of solubilized Cd2+ using the extracellular polymeric substances (EPS) produced by Bacillus sp. MC3B-22 and Microbacterium sp. MC3B-10 (Microbactan); these bacteria were originally isolated from intertidal biofilms off the coast of Campeche, Mexico. EPS were incubated with different concentrations of cadmium in ultrapure water. Residual Cd2+ concentrations were determined by Inductive Coupled Plasma-Optic Emission Spectrometry and the maximum sorption capacity (Qmax) was calculated according to the Langmuir model. EPS were characterized by X-ray photoelectron spectroscopy (XPS) before and after sorption. The Qmax of Cd2+ was 97 mg g-1 for Microbactan and 141 mg g-1 for MC3B-22 EPS, these adsorption levels being significantly higher than previously reported for other microbial EPS. In addition, XPS analysis revealed changes in structure of EPS after biosorption and showed that amino functional groups contributed to the binding of Cd2+, unlike other studies that show the carbohydrate fraction is responsible for this activity. This work expands the current view of bacterial species capable of synthesizing EPS with biosorbent potential for cadmium and provides evidence that different chemical moieties, other than carbohydrates, participate in this process.

Biofouling inhibition by Staphylococcus aureus extracts and their potential use for paints / Inhibición de la bioincrustación por extractos de Staphylococcus aureus y su uso potencial para pinturas

For the control of biofouling, some paints based on compounds that are toxic to marine organisms have been used. There is an intensive search for biodegradable solutions that are friendly to non-target organisms. Bacteria have been shown to be a source of compounds with antifouling potential. In this work, the antifouling activity of a strain of Staphylococcus aureus was evaluated. Extracts activity against biofilm-forming bacteria and the toxicity against Artemia franciscana were evaluated. The extracts were incorporated in a hard gel and a paint matrix, and they were exposed to the sea. In both the laboratory and field, we found that the compounds produced by S. aureus have antifouling activity. The non-toxicity of the tested extracts against Artemia franciscana nauplii suggests that the extracts obtained from S. aureus could have a low ecological impact over non-target organisms. Significant differences were found in the percentage of organisms cover in hard gels with extracts and control. After 90 days, important differences were also observed between the percentage of organisms cover of the paints that contained extracts and the control. Dichloromethane extract is the most effective for the inhibition or delay of the settlement of organisms For this reason, they could be used in matrices with different applications, such as in the shipping industry, aquaculture, or any other in which biofouling is a cause of inconvenience.(AU)

Marine bacteria from the Gulf of California with antimicrofouling activity against colonizing bacteria and microalgae / Bacterias marinas del Golfo de California con actividad antimicrobiana frente a bacterias colonizadoras y microalgas

Abstract One way of reducing the input of pollutants into the marine environment is to enforce the use of non-toxic antifouling paints in marine protected areas. Thus, the purpose of this study was to detect marine microorganisms that secrete inhibitory substances against bacteria and microalgae to avoid biofouling on manmade structures in La Paz bay, B.C.S., Mexico. The inhibitory potential of 125 bacteria was evaluated against biofilm-forming bacteria. Crude extracts were obtained with methanol and ethyl acetate from 16 bacterial strains that exhibited antagonistic and antibacterial activity in a preliminary screening. Antibacterial and antimicroalgal assays were performed using crude extracts, the minimum inhibitory concentration (MIC) was determined. The highest activity against bacteria and microalgae was found in two strains, Shewanella algae and Staphylococcus sp. The results of this study suggest that extracts of bacteria from the Gulf of California with antimicrobial properties against biofilm-forming bacteria can also prevent the adhesion of microalgae, which may control the development of biofilm formation and, as a consequence, biofouling.(AU)

Resumen Una alternativa para reducir la contaminación en el medio marino es el uso de pinturas anti-incrustantes no tóxicas en áreas marinas protegidas. En el presente estudio se propuso encontrar microorganismos marinos que secreten sustancias capaces de inhibir la adhesión de bacterias y microalgas, de esta manera evitar la bioincrustación en estructuras marinas en la bahía de La Paz, B.C.S., México. Un total de 125 bacterias fueron evaluadas por su capacidad para inhibir el desarrollo de bacterias formadoras de biopelículas. En una selección preliminar de actividad antagónica y antibacteriana, 16 cepas bacterianas mostraron potencial actividad inhibitoria, de las que se obtuvieron los extractos crudos con metanol y acetato de etilo. Se realizaron ensayos antibacterianos y anti-microalgales utilizando los extractos crudos, se determinó la concentración mínima inhibitoria (MIC). Dos cepas mostraron la mayor actividad contra bacterias y microalgas: Shewanella algae y Staphylococcus sp. Los resultados de este estudio sugieren que los extractos de bacterias aisladas en el Golfo de California que poseen propiedades antimicrobianas contra las bacterias formadoras de biofilm y también pueden prevenir la adhesión de microalgas, con lo que se podría controlar el desarrollo de la formación de biopelículas y como consecuencia, el biofouling.(AU)

The kelp macrocystis pyrifera as nutritional supplement for goats

The present study was aimed to evaluate Macrocystis pyrifera (MP) meal as a nutritional supplement for goats. There is an increasing interest to look at nutritional alternatives to guarantee a continuous supply of good quality forage for goats, in many communities around the world. Given its abundance and chemical composition, the algae M. pyrifera is an important potential resource as animal feed. Three diets with 10, 20, and 30% of MP meal concentrations and a control diet, with no algae, were evaluated. Four rumen cannulated goats, housed individually in metabolism cages, were used. The experimental design was a 4 x 4 Latin-Square. Feed and water intake, excreted urine and faeces, were measured. Digestibility in vivo, dry matter (DM) disappearance, and the metabolic variables of pH and ammoniacal nitrogen in the rumen, were determined. There was no significant difference in the feed intake but there was in water intake and urine excreted. No significant difference in digestibility in vivo among diets (P>0.05) was found. A significant difference (P<0.05) for degradability in situ was found for the algae diets containing 10 and 30 percent MP concentrations at 96 hours of sampling (78.3 and 82.2 percent). The raw algae in situ digestibility was 77 percent. A potential degradability of 87.3 percent was obtained with 30 percent MP diet. The highest effective degradation was obtained at an estimated rate of 0.02 h-1. Ruminal pH was higher (P<0.05) in all MP treatments (10 percent MP: 6.83, 20 percent MP: 6.85, 30 percent MP: 6.91). As suggested by the results, M. pyrifera represents a good unconventional feeding as a nutritional supplement for goats.

El objetivo de este trabajo fue evaluar Macrocystis pyrifera (MP) como suplemento alimenticio para cabras. Hay un interés creciente en buscar alternativas alimenticias para garantizar el suministro continuo de forraje de buena calidad para cabras en muchas comunidades del mundo. Dada su abundancia y composición química, el alga M. pyrifera es un recurso potencial importante como pienso para ganado. Se evaluaron tres dietas con concentraciones de 10, 20, y 30 por ciento de harina de MP, y una dieta control, sin las algas. Se utilizaron cuatro cabras canuladas dispuestas individualmente en jaulas metabólicas. El diseño experimental fue un Cuadrado Latino 4 x 4. El alimento y agua consumidos, la orina y las heces excretadas fueron medidas. Se determinaron la digestibilidad in vivo, la desaparición in situ de la materia seca y las variables metabólicas pH y nitrógeno amoniacal en rumen. No se encontró diferencia significativa en el alimento consumido, ni en la digestibilidad in vivo entre las dietas (P>0,05), pero si hubo diferencia significativa en el consumo de agua y la orina excretada (P<0,05). Se encontró diferencia significativa (P<0,05) para la digestibilidad in situ en las dietas que contenían el 10 y 30% del alga a la hora 96 del muestreo (78,3 y el 82,2 por ciento). La digestibilidad in situ del alga fue de 77 por ciento. Se obtuvo una degradabilidad potencial de 87,3 por ciento con la dieta que contiene 30 por ciento de MP. La mayor degradación efectiva se obtuvo a una tasa estimada de 0,02 h-1. El pH ruminal fue más alto (P<0,05) en todos los tratamientos con MP (10 por ciento de MP: 6,83, 20 por ciento de MP: 6,85, 30 por ciento de MP: 6,91). Los resultados obtenidos sugieren que M. pyrifera representa un buen suplemento nutricional no convencional para cabras.