Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Se hace una descripción ultraestructural de la bacteria Mobiluncus, uno de los agente anaerobios involucrados en la causalidad del síndrome conocido como vaginosis bacteriana. M. mulieris es un bacilo curvo de ca. 3 m de longitud, lofotrico, cuyos flagelos son subpolares. A partir del primoaislamiento puede cocultivarse accidentalmente con un coco Gram positivo y un bacilo Gram negativo, cuyas colonias, semejantes a las de Mobilunicus, miden menos de 0,2 m de diámetro (límite de resolución del ojo humano), por lo que se recomienda analizar las placas de cultivo bajo el microscopio de disección.

Se inoculó Vibrio choleroe (ca. 1x10o UFCAm) en ensaladas de vegetales y se evaluó su supervivencia adicionando jugo de limón ácido a la ensalada, lo que bajó el pH de 45 a 3.4. En estas condiciones no se recuperó la bacteria a los 30 minutos postadición del jugo de limón. Sin embargo, no hubo alteraciones morfológicas en las bacterias, detectables al microscopio electrónico de transmisión (inción negativa) ni al microscopio electrónico de rastreo.

The morphology of one isolate each of Meloidogyne incognita, M.javanica, M. hapla, M. exigua, M. salasi, and M. arabicida, from Costa Rica was studied with the scanning electron microscope. Good characteristics for the differentiation of the six species were found in the labial and cephalic regions of females, males, and second-stage juveniles, but the single most reliable morphological character was the female perineal pattern.

Maize mosaic virus (MMW), a rhabdovirus, was identified associated to maize field plants, showing stunting and continuous chlorotic stripes uniformely distributed over the leaf blade.The virus was detected in field samples by agar-gel immunodifussion. Enveloped, bacilliform virus particles were observed by electron microscopy in thin sections of naturally infected leaf tissue.

The quetzal, Pharomachrus mocinno, is a Neotropical bird whose structural green appears to be cryptic. The electron microscope shows that green barbules are thick segmented ribbons that twist slightly along the main axis and end in a bifid or trifid filament. Pigmented barbules are simpler and may have lateral flaps, Barbules from the browngreen interfase change gradually. Even though the color mechanism is internal, it has a significant influence on feather shape, limited by selection for strength and thermoregulation. These results and computer simulations support the interference air-keratin-melanin model. Irregular organization of the melanin and reduced barbule interlocking are expected when dull coloration is favored, for example, by high predation. The capacity to produce iridescence appears to be an ancient metazoan character lost in amphibians and mammals. Evolutionary convergence of avian structural color is suggested because the specific mechanisms do not parallel phylogeny.

Se describe la localización y ultraestructura de la glándula androgénica de los canarones de télico abierto, Penaeus vannamei y P. stylirostris. La glándula es un cordón celular que se extiende a lo largo del ducto deferente desde la región proximal del ámpula terminal; sin embargo, la naturaleza secretora de esta estructura requiere confirmación. La espermatogénesis en P. stylirostris y Trachypenaeus byrdi (télico cerrado) es sincronizada y la morfología ultraestructural de los estados de espermatogénesis observados es diferente a la descrita para Sicyonia ingentis. Las espermátidas de P. stylirostris experimentan polimerización gradual de la espina en el ducto medio descendente y las de T. byrdi parecen completar su maduración en el télico de la hembra, luego de la cópula. Las observaciones ultraestructurales de la oogénesis en T. byrdi indican que oocitos de 5-10 un están en previtelogénesis, separados de oocitos en vitelogénesis por una fina membrana. Al inicio de la vitelogénesis primaria los oocitos miden de 610 m y carecen de células foliculares a su alrededor. Oocitos en vitelogénesis secundaria presentan un estrato delgado de células foliculares, envoltura vitelina, especializaciones internas como criptas corticales, cisternas de vesículas de anillo y red de microtúbulos.

An histological and ultrastructural morphological analysis was carried out to compare the articular surface of the Temporomandibular Joint (TMJ) from different rodents: rat, guinea pig, hamster and rabbit. The main components of the TMJ in mammals are: condyl, capsule and articular disk and these structures are organized as follow: an external layer of undiferentiate cells, a second layer of fibroblasts, under which one can find a fibrous cartilage followed by bone structure. In the case of disk, its structure is free of bone, We observed qualitatively that the articular surfaces from components of TMJ have not the same wide in its total long, probably due to changes induced by mechanical forces in certain areas. Although in the TMJs of a guinea pig analyzed we found histological alteration as had been reported by others resulting from pathological cases. The main goal of the present study is to add information about normal composition through the finest details of the articular surfaces for the components of the TMJ.

Normal and pathological human nasal mucous biopsies were used and obtained surgically. Pathological one were taken from cocaine adicted patients who had been using this drug during many years mainly by snorting via. From the clinical point of view all patients presented similar symptoms among which the most common were acute and chronic rhinitis, sneeze and bleeding. All cases include showed evident tissue desorganization that ultrastructurally present parcial or total lost of cillia as well as disruption between epithelia and basal lamina. Although, normal tissue was substituited by abundant fibrous tissue explaining why this tissue lost its normal function. All described alterations were analized by transmission electron microscope and scanning electron microscope.

A new rotary-shadowing process to obtain freeze-drying replicas is described for the analysis of virus ultrastructure, using the inner capsid of human rotavirus as a model. The findings corroborate the icosahedral symmetry with an arrangement pattern of capsomers of T=13L.

We developed a simple method for immunolabelling viral glycoproteins on surface of infected ceil monolayers. Cells 9 hours post-infected with Sendai virus were fixed and treated with polyclonal antibody anti HN glycoprotein (Rabbit IgG), labelled with goat immunoglobulin anti rabbit IgG conjugated with colloidal gold particles. Then, the cells were shadowed with platinum-carbon, covered with nitrocellulose glue, and digested with domestic bleach, washed, and replica fragments were caught with uncovered grid.