Ceratocystis fimbriata agente causal de la enfermedad de marchitez vascular de Tectona grandis L.f. (teca) en Ecuador / Ceratocystis fimbriata causative agent of vascular wilt disease of Tectona grandis L.f. (teak) in Ecuador

Tectona grandis L.f. es una especie forestal de madera dura que, a pesar de no ser nativa de América, su plasticidad de adaptación ha permitido que en Ecuador se establezcan plantaciones intensivas con fines de exportación. Una compleja enfermedad con características de marchitez vascular está matando miles de árboles de diferentes edades en el país. Se planteó conocer el agente fitopatógeno causante de la patogénesis y muerte de los árboles. Se aislaron los hongos Fusarium sp. y Ceratocystis fimbriata Ellis & Halst. desde árboles enfermos. A nivel de invernadero se plantearon los postulados de Koch, para el efecto 30 plantas de T. grandis de cuatro meses de edad por cada tratamiento, se inocularon con los microrganismos como se describe a continuación: T1= C. fimbriata, T2 = Fusarium sp., T3 = C. fimbriata + Fusarium sp., T4 = agar-agar (control). Se empleó un diseño completo al azar (DCA) y las plantas se evaluaron a los 45 días después de inoculadas. Los tratamientos C. fimbriata, y C. fimbriata + Fusarium sp., mostraron mayores volúmenes aparentes de necrosis, con 1.52 cm3 y 1.93 cm3, y plantas muertas por la infección durante el tiempo de evaluación, mientras que Fusarium sp. mostró baja o nula patogenicidad y comportamiento similar al control, con 0.27 cm3 y 0.16 cm3 respectivamente. Estos resultados sugieren que el agente causal de la enfermedad de marchitez vascular en T. grandis es C. fimbriata y sería el primer reporte del fitopatógeno atacando teca en Ecuador. (AU)

Tectona grandisL.f. it is a hardwood forest species, which despite not being native to America, its adaptive plasticity has allowed intensive plantations to be established for export purposes in Ecuador. A complex disease with characteristics of vascular wilt is killing thousands of trees of different ages in the country. It was proposed to know the phytopathogenic agent causing the pathogenesis and death of the trees. Fusarium sp. andCeratocystis fimbriata Ellis & Halst. were isolated from diseased trees. At the greenhouselevel, Koch's postulates were proposed, for the effect 30 four month old T. grandisplants for each treatment were inoculated with the microorganisms as described below: T1 = C. fimbriata, T2 = Fusariumsp ., T3 = C. fimbriata+ Fusariumsp., T4 = agar-agar (control). A complete randomized design (DCA) was used and the plants were evaluated 45 days after inoculation. The treatments C. fimbriata, and C. fimbriata+ Fusariumsp. showed higher apparent volumes of necrosis, with 1.52 cm3and 1.93 cm3, and plants killed by the infection during the evaluation time, while Fusariumsp. showed low or no pathogenicity and behavior similar to the control, with 0.27 cm3and 0.16 cm3respectively. These results suggest that the causative agent of vascular wilt disease in T. grandisis C. fimbriataand it would be the first report of phytopathogen attacking teak in Ecuador. (AU)

Dogma de la bacteriología y otros eventos como puntas de lanza de la virología / The dogma of bacteriology and other events as spearheads of virology

Esta investigación analiza algunos de los eventos principales del siglo XIX que condujeron hacia lacristalización de la virología. En los documentos de aquella época, se plasmó una relación de causalidadentre virus y enfermedad o contagio, y en este contexto patológico, se elaboraron las nociones devirus fijo, virus volátil, contagium vivum fluidum y contagium fixum. De otro lado, la transformaciónconceptual hacia el virus como objeto tecnocientífico tuvo lugar con base en el criterio de filtrabilidady en la metodología trazada por la bacteriología convertida en dogma. Asimismo, se subraya laprimacía no solamente del estudio del virus del mosaico del tabaco sino también de enfermedadesvirales en animales y en el hombre, lo cual permitió el descubrimiento de estos agentessubmicroscópicos mediante un proceso desencadenado por la apropiación de diversas tecnologíasy por factores políticos y económicos.

This review analyzes some of the main events during the twentieth century that led to the birth ofvirology. In the literature of the time, a relationship of causality was established between virus anddisease, and within this pathological context, the notions of fixed virus, volatile virus, contagiumvivum fluidum and contagium fixum were formed. The transformation of the virus concept as atechnoscientific object took place based on the criterion of filterability and on the methodologydevised for the bacteriology dogma. Studies on tobacco mosaic virus are highlighted, as well asthose on viral diseases of human beings and animals, which led to the discovery of thesesubmicroscopic agents through the appropriation of technologies and the impulse triggered bypolitical and economic factors.

The biofilm concept and its role in prevention of periodontal disease: [review] / O conceito de biofilme e seu papel na prevenção da doença periodontal: [revisão]

OBJECTIVE: To provide an overview of the history of oral microbiology, a discussion of dental plaque as both a microbial community and a biofilm, and a review of the measures available to control the oral microflora. METHODOLOGY: The author reviewed the literature related to oral microbiology and associated infectious diseases. He also examined articles that detailed the structure and physiology of biofilms, including dental plaque biofilms. RESULTS and DISCUSSION: Biofilms cannot be eliminated. The pathogenic nature of the dental plaque biofilm can be diminished in the oral cavity by reducing the bioburden and effectively maintaining a normal oral flora via oral hygiene procedures that include daily toothbrushing, flossing and rinsing with an antimicrobial mouthrinse. An oral hygiene regimen that includes rinsing with an antimicrobial mouthrinse is a practical approach to the prevention and management of periodontal diseases.This strategy may have wider benefits when the link between periodontal disease and certain systemic diseases is considered. CONCLUSION: An effective oral hygiene regimen can help control dental plaque biofilm and associated periodontal diseases.

OBJETIVOS: Apresentar uma visão panorâmica da história da microbiologia bucal, uma discussão sobre a placa dental como uma comunidade microbiana e como biofilme, e uma revisão das medidas disponíveis para controle da microflora bucal. METODOLOGIA: O autor revisou a literatura relacionada com microbiologia bucal e doenças infecciosas associadas. Igualmente examinou artigos que detalharam a estrutura e a fisiologia dos biofilmes, incluindo biofilme da placa dental. RESULTADOS E DISCUSSÃO: Biofilmes não podem ser eliminados. A natureza patogênica do biofilme placa dental pode ser diminuída pela redução da carga biolótica e mantendo efetivamente a flora normal por meio de procedimentos de higiene bucal, que incluem escovação diária, uso de fio dental e colutórios com antimicrobianos. Essa estratégia pode ter benefícios amplos quando a ligação entre doença periodontal e certas doenças sistêmicas é considerada. CONCLUSÃO: O regime efetivo de higiene bucal pode ajudar no controle do biofilme placa dental e doenças periodontais associadas.

The white band disease type II pathogen in Puerto Rico / El patógeno de la enfermedad de la banda blanca tipo II en Puerto Rico

The white band disease type I (WBD-I) epizootic event of the early 1980’s resulted in significant changes in the structure and composition of coral communities throughout the wider Caribbean. The disease decimated populations of acroporid corals throughout their geographic distribution and it is still affecting the surviving and recovering populations of these corals in a number of localities in the wider Caribbean. The putative pathogen for this syndrome (WBD-I) was never identified. A second pattern of white band was described later as white band type II (WBD-II). A potential pathogen named Vibrio charchariae was identified but Koch’s postulates were never fulfilled. In this work, we present results of a preliminary approach to confirm the identity of the pathogen of WBD-II. During the fall months of 2004, samples of Acropora cervicornis with signs of WBD-II were collected from a small population in Mario reef, an isolated patch reef off La Parguera, southwest coast of Puerto Rico. Bacteria extracted from these samples were isolated in TCBS agar, grown in Glycerol Seawater agar, and then used to inoculate separated, healthy-looking colonies of the same population in the same reef. Isolation, culture, and inoculations of bacteria were conducted under controlled conditions within hours of collection, and no microorganisms that were not already in the reef community were introduced with these experiments. Some of the newly inoculated colonies developed the disease signs within 24 hr. These were subsequently sampled and bacterial re-isolated to be identified, thus complying with the first steps to fulfill Koch ’s postulates for this disease. Rates of advance of the disease signs varied between 0.5 and 2 cm/day. Preliminary analyses indicated that the potential cause of WBD-II is a Vibrio species very close to Vibrio harveyi, a synonymy of V. charchariae. All inoculated coral colonies that developed the signs of WBD-II, behaved as the naturally infected colonies, and all of them showed no signs of the disease after two months of the inoculation when water temperatures dropped due to winter in the area. Rev. Biol. Trop. 54 (Suppl. 3): 59-67. Epub 2007 Jan. 15.

El evento epizoótico de la enfermedad de banda blanca tipo I (WBD-I) al principio del decenio de 1980 causó cambios significativos en la composición de las comunidades coralinas a todo lo largo del Gran Caribe. La enfermedad eliminó altas proporciones de las poblaciones de acropóridos y aún hoy continua afectando la recuperación de sus poblaciones en muchas localidades. El agente causante de esta enfermedad (WBD-I) nunca fue identificado. Un conjunto de características diferentes de esta enfermedad fue descrito en 1998, como banda blanca tipo II (WBD-II), y la bacteria Vibrio charchariae fue identificada como la posible causante. Sin embargo, los postulados de Koch nunca se cumplieron. En este trabajo presentamos los resultados de estudios preliminares para identificar el agente causante de WBD-II en el Caribe. Durante los meses de otoño del 2003 y 2004, recolectamos muestras de Acropora cervicornis con signos de WBD-II en Mario, un arrecife de parche aislado en La Parguera, costa sur occidental de Puerto Rico. Las bacterias extraídas de estas muestras fueron aisladas en agar TCBS, criadas en agar Glicerol Agua de mar y luego utilizadas para infectar colonias separadas sin signos de enfermedad en la misma población y localidad. El aislamiento, cultivo e inoculación de bacterias se hizo en condiciones controladas, y no introdujimos ningún microorganismo que no hubiera estado previamente en el arrecife. Algunas de las colonias inoculadas desarrollaron signos de la enfermedad en 24 hr. Tomamos muestras de estas colonias y las bacterias fueron nuevamente aisladas para ser identificadas y así completar los postulados de Koch. Las tasas de avance de los signos de la enfermedad variaron entre 0.5 y 2 cm/día. Preliminarmente confirmamos que la causa de WBD-II es una especie de Vibrio muy cercana a Vibrio harveyi, sinónimo de V. charchariae. Todas las colonias coralinas inoculadas que desarrollaron signos de WBD-II se comportaron como las colonias infectadas naturalmente y ninguna de ellas presentó signos de la enfermedad al cabo de dos meses, cuando las temperaturas del agua descendieron con el invierno.