High intragenomic heterogeneity of 16S rRNAgenes in a subset of Vibrio vulnificus strains from the western Mediterranean coast

Heterogeneity among ribosomal operons in Vibrio vulnificus is purported as a probabilistic indicator of strain virulence and classifies V. vulnificus strains as 16S rRNA genes type A and B. In this study, 16S rRNA genes typing of V. vulnificus strains isolated from the Valencia city coast, in the western Mediterranean, showed that 24 out of 30 isolates were type A, one was type B and five could not be typed. Single strand conformation polymorphism (SSCP) analysis of this gene region revealed complex patterns indicative of intragenomic ribosomal operon sequence heterogeneity. The 16S rRNA genes of three untypeable isolates C27, C30, and C34, along with type A (ATCC 27562) and B (C7184) reference strains, were amplified, cloned and sequenced. The number of unique 16S rRNA gene sequences was 4, 3, and 4 for the environmental isolates. The type strain of the species (ATCC 27562) presented only two 16S rRNA gene types, while the reference isolate C7184 of clinical origin had only one 16S rRNA gene type. Sequences differed from five to 35 bp (99.6% to 97.6% sequence similarity). Areas of variability concentrated in helices 10, 18, and 37 and included variants with short intervening sequences in helix 10. Most of the substitutions showed compensatory mutations suggesting ancient sequence divergence generated by lateral gene transfer (AU)

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Inmunotecnología aplicada al campo marino / Immunotechnology applied to the marine field

Gracias a sus innumerables aplicaciones, la innovadora técnica de producción de anticuerpos monoclonales (AcsMo) diseñada por los Dres. Köhler y Milstein en 1975 ha revolucionado no sólo el campo biomédico, sino a diversos ámbitos científicos. Aquí mostramos algunos ejemplos de su aplicación en los campos de la Biología y Ecología marinas. España es una potencia mundial en cuanto a producción mejillonera, y cuenta con importantes explotaciones de otras especies de bivalvos. Con el fin de optimizar el rendimiento de esta actividad existen al menos tres aspectos en los que la Inmunotecnología promete ser una herramienta de gran utilidad: 1) Los problemas asociados a las toxinas marinas producidas por floraciones de microalgas tóxicas, obligando al cese de la extracción de bivalvos. Los riesgos podrían ser minimizados mediante una mejora en la monitorización de estos episodios con ayuda de los AcsMo. 2) Detección de toxinas en los bivalvos. El método más utilizado internacionalmente es el bioensayo (inyección de ratones con extractos de bivalvos), pero se están buscando métodos alternativos utilizando AcsMo frente a algunas de las toxinas. 3) Desarrollo de técnicas inmunológicas que permitan la discriminación rápida y fiable de las larvas de mejillón y las larvas de otras especies de bivalvos (muy semejantes morfológicamente). Esto permitiría asesorar al sector mejillonero para optimizar la obtención de cría de mejillón. Así, la Inmunotecnología abre enormes posibilidades en el campo marino, como son la discriminación de especies, mejora de la acuicultura, control de toxinas, estudios ecológicos, o el estudio del sistema inmune de diversos organismos marinos

Thanks to its innumerable applications, the innovative technique of monoclonal antibodies (mAbs) developed by Köhler and Milstein in 1975 has revolutionized not only the biomedical field, but also other sciences. Here, we show some examples of its potential application in Marine Biology and Ecology, especially in the mussel sector and with marine toxins. Spain is an important world producer of mussels and other bivalves, such as oysters and clams. There are at least three aspects in which immunology promises to be a powerful tool for helping to optimize the yield of this activity. These are related to: 1) The problems associated with the marine toxins produced during blooms of toxic microalgae species, which force a halt in the production of bivalves. The use of mAbs to improve the monitoring of toxic algae blooms could minimize such problems. 2) The detection of toxins in the bivalves. Although the most commonly used method, internationally, is a bioassay (injection of mice with bivalve extracts), immunoassays using mAbs against the toxins may be an alternative method. 3) The development of immunological techniques for an accurate identification of mussel larvae: the mAbs can distinguish mussel larvae from other bivalve larvae (very similar in morphology), allowing analysis of the spatio-temporal distribution of the larvae with the aim of optimizing the production of mussels. Moreover, the use of immunological techniques is helping to improve species discrimination, fishing control, the handling of aquaculture, toxin controls and ecological studies, such as those about the immune system of diverse marine organisms