Kinetics of growth of Leishmania (Leishmania) chagasi cycle in McCoy cell culture

Cinéticas de crescimento de Leishmania realizadas in vitro após a internalização da forma promastigota na célula e a ocorrência da transformação do parasito na forma amastigota foram descritas por vários autores, seja com a utilização de explantes de macrófagos em células de baço de hamster ou atualmente da célula de linhagem de macrófago humano U937. Aliando a microscopia à descrição das inter-relações morfológicas e à síntese de moléculas específicas foi possível esclarecer pontos sobre a biologia do parasito. O presente estudo mostra o acompanhamento do ciclo de crescimento da Leishmania chagasi em uma cinética realizada com células de linhagem McCoy, no período de 144 horas. Durante o processo, as transformações morfológicas foram reveladas pela reação de imunofluorescência indireta (RIFI) e as moléculas liberadas no meio extracelular foram observadas pelo método de SDS-PAGE, em intervalos de 24 horas no período de 144 horas. Observou-se que nas primeiras 72 horas, a forma promastigota da L. chagasi fica aderida à membrana das células com aspecto arredondado (amastigota-like). Em 96 horas as células infectadas apresentaram alterações morfológicas; em 120 horas, as células liberaram, para o meio extracelular, antígenos fluorescentes solúveis; e em 144 horas foram observadas novas formas alongadas dos parasitos como se fossem promastigotas. No SDS-PAGE, proteínas com pesos moleculares específicos são observadas em cada ponto da cinética, mostrando que a célula McCoy parece mimetizar o macrófago e que pode ser um modelo útil para o estudo da infecção do binômio leishmânia/célula.The kinetics of growth of Leishmania performed in vitro after internalization of the promastigote form in the cell and the occurrence of the transformation of the parasite into the amastigote form have been described by several authors. They used explants of macrophages in hamster spleen cell culture or in a human macrophage lineage cell, the U937. Using microscopy, the description of morphologic inter-relationship and the analysis of the production of specific molecules, it has been possible to define some of the peculiarities of the biology of the parasite. The present study shows the growth cycle of Leishmania chagasi during the observation of kinetic analysis undertaken with a McCoy cell lineage that lasted for a period of 144 hours. During the process, the morphologic transformation was revealed by indirect immunofluorescence (IF) and the molecules liberated in the extra cellular medium were observed by SDS-PAGE at 24-hour intervals during the whole 144-hour period. It was observed that in the first 72 hours the promastigote form of L. chagasi adhered to the cell membranes and assumed a rounded (amastigote-like) form. At 96 hours the infected cells showed morphologic alterations; at 120 hours the cells had liberated soluble fluorescent antigens into the extra cellular medium. At 144 hours, new elongated forms of the parasites, similar to promastigotes, were observed. In the SDS-PAGE, specific molecular weight proteins were observed at each point of the kinetic analysis showing that the McCoy cell imitates the macrophage and may be considered a useful model for the study of the infection of the Leishmania/cell binomial

Life-cycle of Scinaia interrupta (Nemaliales, Rhodophyta)

Copyright © Springer Science+Business Media B.V. 2011.The life-cycle of Scinaia interrupta (A.P. de Candolle) M. J. Wynne was investigated in vitro using four irradiance regimes: 4, 8, 12 and 16 μmol photons mˉ² sˉ¹. A triphasic heteromorphic life-cycle was observed. Carpospores released by cystocarps of gametophytes collected in the field developed into filamentous tetrasporophytes, which produced tetrahedral tetrasporangia. Tetrasporangial development was accelerated under higher irradiance levels. Tetraspores germinated into filamentous protonemal gametophytes, initially identical to the tetrasporophyte. Filamentous gametophytes developed apical utricles and gave rise directly to the fleshy gametophyte. Further development of the fleshy gametophyte was not observed at the lowest irradiance regime (4 μmol photons mˉ² sˉ¹). The present study reports for the first time the influence of the irradiance regime on the initial tetrasporangial development and in the development of the fleshy gametophyte, and reinforces the importance of light intensity on Scinaia life-cycle. Production of apical utricles by the filamentous gametophyte is newly reported for the genus

The algal flora of the Azores: a historical and biogeographical approach.

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008

Azorean Coastal Communities. An On-going Study.

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008

The marine algal (seaweed) flora of the Azores: 4, further additions

Eight records of seaweeds are reported new to the mid-Atlantic Azores archipelago. Coelothrix irregularis and Lejolisia sp. fall within their overall distributional range. Sebdenia rodrigueziana and Syringoderma floridana have their north-western limit of distribution there. The islands represent the western limit of occurrence for Antithamnionella boergesenii, Aphanocladia stichidiosa, Sebdenia dichotoma, and Codium effusum. The presente and previous papers in this series reveal the extension in range distribution to the west of many of the new records found in the Azores, raising the question as to why the western Atlantic acts as a barrier to dispersal. The new records presented here increase the current total of species recorded on the Azores to 385 (55 Chlorophyta, 74 Heterokontophyta (Phaeophyceae), and 256 Rhodophyta), showing that this isolated island group supports a relatively rich benthic marine algal flora

Creativity in elementary school : inhibiting and facilitating factors according to school principals

Este estudo investigou a percepção de gestores de instituições de ensino fundamental sobre fatores que dificultam o professor promover o desenvolvimento da criatividade discente e procedimentos que poderiam utilizar para apoiar o professor na promoção da criatividade em sala de aula. Participaram 118 gestores de escolas públicas e particulares, os quais responderam a uma checklist de barreiras à criatividade em sala de aula e quatro questões abertas. Fatores inibidores mais apontados foram: desconhecimento pelo professor de práticas pedagógicas que poderiam ser utilizadas para propiciar o desenvolvimento da criatividade dos alunos e falta de entusiasmo pela atividade docente. Orientação, apoio e incentivo ao docente foi o procedimento mais apontado pelos gestores para auxiliar o professor a desenvolver a criatividade de seus alunos.This study investigated the perception of school principals regarding factors that hamper teachers to promote the development of student’s creativity and strategies that the school principal could use to support teachers in the promotion of creativity in the classroom. The participants were 118 school principals from public and private schools, who completed a checklist of obstacles to creativity in the classroom and four open questions. The most frequent obstacles pointed out were teachers’ lack of knowledge of pedagogical practices to favor the development of students’ creativity and teacher's lack of enthusiasm. Guidance, support and incentive to teachers were the most frequently pointed out procedures to assist the teacher in fostering the creativity of their students

The use of digital photography for the definition of coastal biotopes in Azores.

Copyright © Springer Science+Business Media B.V. 2007.Sampling benthic communities usually requires intensive field and lab work which is generally performed by skilled staff. In algal dominated communities, like those on the shores of the Azores, biotope characterization studies focused on the more conspicuous algae categories, thus reducing the skills required for species identification. The present study compares in situ quadrat quantifications done by a skilled reader, with computer based quadrat quantifications using digital photographic records of the same areas read in situ, accomplished by skilled and non-skilled readers. The study was conducted inter- and subtidally at various shore heights/depths. Quantification of algal coverage, both in situ and computer based, used the point to point method with quadrats of 0.25 m × 0.25 m for the intertidal, and 0.50 m × 0.50 m for the subtidal surveys, both subdivided into 36 intersection points. Significant differences were found between in situ readings and computer based readings of photographic records conducted both by experienced and inexperienced readers. Biotopes identified using in situ data and image based data differ both for the subtidal and intertidal

Creatividad en la aula : factores inhibidores y facilitadores segundo coordinadores pedagógicos

Este estudo investigou, em uma amostra de 66 coordenadores pedagógicos de instituições de ensino fundamental, fatores que dificultam o professor a estimular o desenvolvimento da criatividade discente e procedimentos que o coordenador poderia utilizar para apoiar o docente na promoção da criatividade em sala de aula. Os participantes responderam um questionário composto por uma checklist de barreiras à criatividade em sala de aula e quatro questões abertas. Desconhecimento pelo professor de práticas pedagógicas para favorecer o desenvolvimento da criatividade discente e de textos a esse respeito, além de insegurança para testar novas práticas pedagógicas foram os fatores inibidores mais sinalizados. Oferecer cursos para professores, além de orientação, apoio e incentivo aos docentes foram os procedimentos mais apontados pelos coordenadores para auxiliar o professor a encorajar a criatividade em sala de aula.This study investigated, in a sample of 66 elementary school pedagogical coordinators, factors that hamper teachers to stimulate the development of student creativity and strategies to be used by the coordinator to support teachers in promoting creativity in the classroom. Participants completed a questionnaire consisting of a checklist of obstacles to creativity in the classroom and four open questions. The most indicated inhibitory factors included the lack of knowledge by the teachers of pedagogical practices that favor the development of students’ creativity and of texts in this respect, as well as insecurity to test new pedagogical practices. Providing courses, guidance, support and incentive for teachers were the procedures most frequently pointed out by coordinators to assist the teacher in encouraging creativity in the classroom.Este estudio investigó, en una muestra de 66 coordinadores pedagógicos de instituciones de Enseñanza Primaria, factores que dificultan al maestro la estimulación del desarrollo de la creatividad del estudiante y también procedimientos que el coordinador podría utilizar para apoyar al profesor para promover la creatividad en clase. Los participantes respondieron un cuestionario compuesto por una lista de barreras a la creatividad en clase y cuatro preguntas abiertas. Desconocimiento por el profesor de prácticas pedagógicas para favorecer el desarrollo de la creatividad y de textos en este sentido, además de inseguridad para experimentar nuevas prácticas pedagógicas fueron los factores inhibidores más marcantes. Ofrecer cursos para maestros, así como orientación, apoyo e incentivo fueron los procedimientos más señalados por los coordinadores para auxiliar al profesor a fomentar la creatividad en clase

CARACTERÍSTICAS DE UMA FAVELA DA REGIÃO DA GRANDE SÃO PAULO

Os autores descrevem os resultados de um levantamento de condições sócio-sanitárias jeito em uma favela da Região da Grande São Paulo, área industrializada do sudeste brasileiro.The authors describe results of a survey on social-economical conditions of a slum area of Greater São Paulo, wich is an industrial region of south-eastern Brazil