Conidial germination of Botryosphaeria dothidea Mough.: Fr (Ces. & De Not.) and histological alterations on stems of pitahaya (Hylocereus undatus H.) (Haworth) Britton & Rose

Conidial germination of Botryosphaeria dothidea (anamorph: Fusicoccum) in sterile distilled water and 1% sterile dextrose solution was evaluated at 4, 6, 12, 24 and 36 h after incubation. Also, it was described the anatomical changes on pitahaya stems induced by this fungus, collected in the field and artificially inoculated in the laboratory. Conidial germination was less than 30% in water and it was improved when 1% dextrose was added to the water. In 1% dextrose solution the germination was 90% after 4h of incubation and 100% at 6 h. Pathogen germ tubes had entered through wounds and sometimes through stomata and hyphae colonized intra and intercellularly in the parenchyma-chlorenchyma tissues. On naturally and artificially diseased stems the main alterations were: destruction of cuticle, hyperplasia of epidermal and collenchymatous hypodermal cells and conform the advance of the pathogen a layer of lignified periderm was formed surrounding the damaged tissues; however, it couldn't stop the advance of the pathogen and the cells that surrounded the lesion suffered necrosis.

Odontodisplasia regional : caso clínico

La odontodisplasia regional, también denominada diente fantasma o detención localizada del desarrollo dental, es una anomalía estructural del desarrollo, compleja y rara. Su etiología es desconocida y no presenta un patrón hereditario, aunque se han considerado factores locales como alteraciones vasculares y traumatismos locales. Puede afectar ambas denticiones: temporal y permanente; existe una anormal aposición dentinaria, que a su vez está detenida precozmente. Se encuentran afectados todos los componentes histológicos del órgano dentario y radiográficamente el aspecto fantasma es típico: raíces cortas, coronas que semejan cáscaras y aspecto dismórfico general. Se recibieron estudios radiográficos correspondientes a una niña de 10 años derivada del Hospital Materno Infantil de la ciudad de Azul, provincia de Buenos Aires. Luego del análisis de signos radiográficos se determina el diagnóstico de odontodisplasia regional en los cuadrantes superior e inferior izquierdos. Se sugiere la investigación de antecedentes traumáticos al presentarse la lesión en dos cuadrantes isolaterales.