Myelin-associated neurite growth-inhibitory proteins and suppression of regeneration of immature mammalian spinal cord in culture.

Neurite outgrowth across spinal cord lesions in vitro is rapid in preparations isolated from the neonatal opossum Monodelphis domestica up to the age of 12 days. At this age oligodendrocytes, myelin, and astrocytes develop and regeneration ceases to occur. The role of myelin-associated neurite growth-inhibitory proteins, which increase in concentration at 10-13 days, was investigated in culture by applying the antibody IN-1, which blocks their effects. In the presence of IN-1, 22 out of 39 preparations from animals aged 13-17 days showed clear outgrowth of processes into crushes. When 34 preparations from 13-day-old animals were crushed and cultured without antibody, no axons grew into the lesion. The success rate with IN-1 was comparable to that seen in younger animals but the outgrowth was less profuse. IN-1 was shown by immunocytochemistry to penetrate the spinal cord. Other antibodies which penetrated the 13-day cord failed to promote fiber outgrowth. To distinguish between regeneration by cut neurites and outgrowth by developing uncut neurites, fibers in the ventral fasciculus were prelabeled with carbocyanine dyes and subsequently injured. The presence of labeled fibers in the lesion indicated that IN-1 promoted regeneration. These results show that the development of myelin-associated growth-inhibitory proteins contributes to the loss of regeneration as the mammalian central nervous system matures. The definition of a critical period for regeneration, coupled with the ability to apply trophic as well as inhibitory molecules to the culture, can permit quantitative assessment of molecular interactions that promote spinal cord regeneration.

The prion protein gene: Identifying regulatory signals using marsupial sequence

The function of the prion protein gene (PRNP) and its normal product PrPC is elusive. We used comparative genomics as a strategy to understand the normal function of PRNP. As the reliability of comparisons increases with the number of species and increased evolutionary distance, we isolated and sequenced a 66.5 kb BAC containing the PRNP gene from a distantly related mammal, the model Australian marsupial Macropus eugenii (tammar wallaby). Marsupials are separated from eutherians such as human and mouse by roughly 180 million years of independent evolution. We found that tammar PRNP, like human PRNP, has two exons. Prion proteins encoded by the tammar wallaby and a distantly related marsupial, Monodelphis domestica (Brazilian opossum) PRNP contain proximal PrP repeats with a distinct, marsupial-specific composition and a variable number. Comparisons of tammar wallaby PRNP with PRNPs from human, mouse, bovine and ovine allowed us to identify non-coding gene regions conserved across the marsupial-eutherian evolutionary distance, which are candidates for regulatory regions. In the PRNP 3' UTR we found a conserved signal for nuclear-specific polyadenylation and the putative cytoplasmic polyadenylation element (CPE), indicating that post-transcriptional control of PRNP mRNA activity is important. Phylogenetic footprinting revealed conserved potential binding sites for the MZF-1 transcription factor in both upstream promoter and intron/intron 1, and for the MEF2, MyTI, Oct-1 and NFAT transcription factors in the intron(s). The presence of a conserved NFAT-binding site and CPE indicates involvement of PrPC in signal transduction and synaptic plasticity. (c) 2004 Elsevier B.V. All rights reserved.

Early pregnancy factor in marsupials

Maternal recognition of pregnancy in marsupials occurs in more subtle ways than it does in eutherians. For instance, unlike in eutherians, the plasma progesterone profiles of pregnant and non-pregnant animals are similar during the luteal phase. It is typically during the brief luteal phase that both gestation and parturition occur in marsupials. Yet histological and physiological changes have been documented between gravid and non-gravid uteri in certain monovular marsupials and between pregnant and non-pregnant animals in polyovular marsupials. Early pregnancy factor (EPF), a 10.8-kDa serum protein known to be homologous to chaperonin 10, is associated with maternal immunosuppression, embryonic development and pregnancy in eutherian mammals. It has been reported in two Australian marsupials: the dasyurid Sminthopsis macroura and the phalangerid Trichosurus vulpecula. This paper documents its occurrence in the New World didelphid Monodelphis domestica. EPF is detectable by rosette inhibition assay in the peripheral circulation of pregnant but not of non-pregnant or pseudopregnant animals. Our work focuses on the embryo–maternal signalling role of EPF during pregnancy. Because progesterone-driven changes are similar in pregnant and non-pregnant marsupials, these animals are an excellent laboratory model in which to investigate the role of EPF in orchestrating the physiological changes necessary to sustain pregnancy.

Preferência alimentar e identificação das principais fontes de repasto sanguíneo de fêmeas Lutzomyia (Diptera: Psychodidae) em áreas endêmicas para leishmaniose visceral na grande Natal

Leishmaniasis are endemic diseases wild spread in the New and Old World, caused by the flagelated protozoan Leishmania. In the New World, the distribution of different forms of leishmaniasis is mostly in tropical regions. In the State of Rio Grande do Norte, Northeast Brazil, 85% of the captured sand flies fauna is Lutzomyia longipalpis. The distribution of the sand fly vector in the state overlaps with the disease distribution, where the presence of sand flies is associated with presence of animals shelters. The aim of this study was to analyse the blood meal preference of sand flies vector from the genus Lutzomyia spp. in laboratory conditions, to verify the vector life cicle at different temperatures sets and to identify the main blood meal source in endemic areas for visceral leishmaniasis (VL) at peri-urban regions of Natal. Sand flies samples were collected from the municipalities of São Gonçalo do Amarante and Nísia Floresta where female sand flies were grouped for the colony maintenance in the laboratory and for the analysis of the preferred source of sand fly blood meal in natural environment. The prevalence of blood meal preference and oviposition for the females sand flies was 97% for Cavia porcellus with oviposition of 19 eggs/female; 97% for Eqqus caballus with 19 eggs/female; 98% for human blood with 14 eggs/female; 71.3% for Didelphis albiventris with 8.4 eggs/female; 73% for Gallus gallus with 14 eggs/female; 86% for Canis familiaris with 10.3 eggs/female; 81.4% for Galea spixii with 26 eggs/female; 36% for Callithrix jachus with 15 eggs/female; 42.8% for Monodelphis domestica with 0% of oviposition. Female sand flies did not take a blood meal from Felis catus. Sand flies life cycle ranged from 32-40 days, with 21-50 oviposition rates approximately. This study also showed that at 32°C the life cycle had 31 days, at 28° C it had 50 days and at 22°C it increased to 79 days. Adjusting the temperature to 35°C the eggs did not hatch, thus blocking the life cycle. A total of 1540 sand flies were captured, among them, 1.310 were male and 230 were female. Whereas 86% of the sand flies captured were Lu. longipalpis as compared to 10.5% for Lu. evandroi and, 3.2% for L. lenti and 0.3% for Lu whitmani. The ratio between female and male sandfly was approximately 6 males to 1 female. In Nísia Floresta, 50.7% of the collected females took their blood meal from armadillo, 12.8% from human. Among the female sand flies captured in São Gonçalo do Amarante, 80 of them were tested for the Leishmania KDNA infectivity where 5% of them were infected with Leishmania chagasi. Female Lutzomyia spp. showed to have an opportunistic blood meal characteristic. The behavioral parameters seem to have a higher influence in the oviposition when compared to the level of total proteins detected in the host s bloodstream. A higher Lu. longipalpis life cycle viability was observed at 28°C. The increase of temperature dropped the life cycle time, which means that the life cycle is modified by temperature range, source of blood meal and humidity. Lu longipalpis was the most specie found in the inner and peridomiciliar environment. In Nísia Floresta, armadillos were the main source of blood meal for Lutzomyia spp. At São Gonçalo do Amarante, humans were the main source of blood meal due to CDC nets placed inside their houses

Diversidade de espécies no complexo Monodelphis brevicaudata (Didelphimorphia:Didelphidae), inferida por dados moleculares e morfológicos

O complexo de espécies M. brevicaudata possui distribuição reconhecida para o Norte da América do sul e compreende três espécies descritas ‐ M. brevicaudata, M. glirina, e M. palliolata ‐ e duas não descritas, reconhecidas em estudos prévios. A delimitação de espécies baseada somente em caracteres morfológicos é complicada, de forma que diversos táxons nominais já foram associados ao grupo e diversos arranjos taxonômicos foram propostos. Os poucos estudos baseados em dados moleculares que incluíram espécimes do complexo brevicaudata revelaram altas taxas de divergência genética. Este trabalho buscou elucidar a sistemática do complexo de espécies M. brevicaudata através do estudo dos padrões de variação morfológica e genética. Para tal, desenvolvemos análises filogenéticas baseadas em dois genes mitocondriais: citocromo b e 16 S rDNA. Adicionalmente, estudamos a morfologia externa e craniana dos espécimes, investigando a existência de congruência entre a variação genética e morfológica. As análises morfológicas foram, em geral, congruentes com as moleculares, as quais indicaram os mesmos clados em todas as análises filogenéticas. Foram formalmente reconhecidas nove espécies para o complexo. Monodelphis brevicaudata, M. palliolata e M. glirina são consideradas espécies válidas; M. touan é revalidado da sinonímia de M. brevicaudata e duas espécies novas são descritas e nomeadas; a espécie M. domestica provou ser intimamente relacionada a espécimes do grupo brevicaudata, sendo aqui considerada como integrante do referido grupo; duas espécies reconhecidas como distintas permanecem sem uma descrição formal; M. maraxina é sinonimizada com M. glirina. Foi observado dimorfismo sexual para as espécies estudadas, sendo que para as duas espécies estatisticamente testadas (teste T de student), M. glirina e M. sp. nov. “Trombetas”, os machos apresentaram crânios significativamente maiores que as fêmeas. Rios de grande porte parecem ter participado na diferenciação genética e estruturação filogeográfica das espécies. O padrão filogeográfico encontrado sugere ao menos dois centros de diversificação para o grupo, um no escudo das Guianas, envolvendo as espécies ao norte do rio Amazonas, e outro no escudo brasileiro, envolvendo M. glirina e M. domestica.

Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae

cDNA coding for two digestive lysozymes (MdL1 and MdL2) of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, purified and characterized. The lytic activities of MdL1 and MdL2 upon Micrococcus lysodeikticus have an acidic pH optimum (4.8) at low ionic strength (μ = 0.02), which shifts towards an even more acidic value, pH 3.8, at a high ionic strength (μ = 0.2). However, the pH optimum of their activities upon 4-methylumbelliferyl N-acetylchitotrioside (4.9) is not affected by ionic strength. These results suggest that the acidic pH optimum is an intrinsic property of MdL1 and MdL2, whereas pH optimum shifts are an effect of the ionic strength on the negatively charged bacterial wall. MdL2 affinity for bacterial cell wall is lower than that of MdL1. Differences in isoelectric point (pI) indicate that MdL2 (pI = 6.7) is less positively charged than MdL1 (pI = 7.7) at their pH optima, which suggests that electrostatic interactions might be involved in substrate binding. In agreement with that finding, MdL1 and MdL2 affinities for bacterial cell wall decrease as ionic strength increases.

Encontro do parasita Hemencyrtus herbertii (Hymenoptera: Encyrtidae) em Musca domestica (Diptera: Muscidae) no Brasil

Relata-se a primeira ocorrência de Hemencyrtus herbertii parasitando pupas de Musca domestica em fezes humanas no Brasil.

Ecologia domestica de la tripanosomiasis americana: perfil alimentario del triatoma infestans en un area rural de la província de Santiago del Estero, Argentina

Se describen los resultados entomológicos de un estúdio sobre transmiswn del Tripanosoma cruzi realizado en un caserío rural de Argentina. Se determino la prevalencia de infección elperfil alimentario de los Triatoma infestans domiciliados, relacionándose su densidad con el tipo de vivienda. Seis de las 18 viviendas estudiadas eran nuevas o mejoradas y en 16 los habitantes aplicaban hexaclorociclohexano. La menor densidad de vinchucas correspondió a las casas higiénicas o mejoradas con tratamiento químico, Los ranchos tratados presentaron un número de insectos 10 veces menor que un rancho no tratado, indicando la efectividad del control autogestado. Se hallaron T. infestans en el 100% de los dormitorios pero en sólo el 53% de los localesperidomiciliarios. Un 39% de las vinchucas intradomiciliarias estaban infectadas. El 96% de los insectos de dormitorios se alimentaron sobre hombre, perro, polloygato, siendo el índice afinidad para el perro 13 veces superior al correspondiente al hombre. Se discute la importancia epidemiológica de la concentración de vectores dentro de los dormitorios y su asociación trófica con los perros convivientes, nsí como la necessidad de combinar la mejora de vivienda con educación sanitaria.

Infestacion domestica por triatoma infestans y prevalencia de seropositivos al Trypanosoma cruzi en un area rural del nordeste argentino

Se llevó a cabo un estúdio epidemiológicopara obtener unpanorama general de la transmisión doméstica del Trypanosoma cruzi en áreas rurales del Departamento San Miguel, Conientes, Argentina. Se investigaron 100 viviendas precarias, 50,0% de las mismas resultó infestado por Triatoma infestans y 1,0% por T. sórdida, citãndose por primera vez para la provinda de Comentes la colonización domiciliaria de esta especie. El 23,1% de T. infestans estaba infectado por T. cruzi. La seroprevalencia de 388 pacientes analizados por hemaglutinacíôn indirecta e inmunofluorescencia indirecta fue 23,4%, destacándose el alto índice (12,9%) constatado en menores de 10 anos. Losporcentajes de seropositividad aumentaron con la edad, alcanzándose 50,0% de infectados entre los 31-40 anos. La infestación doméstica por T. infestans, la prevalencia humana de seropositivos al T. cruzi y las condiciones deprecariedad en que se desenvuelve la vida de los pobladores revelan la vigência de la endemia chagãsica en el área estudiada.

Diferença entre as espécies de Timbó ( Derris Spp., Fabaceae) de diferentes regiões da Amazônia no controle da Musca domestica L.

O pó das raízes das espécies de timbó coletadas em diferentes regiões da Amazônia, testado em agrupamentos de larvas, não produziu efeito diferencial significativo entre duas linhagens de Musca domestica. As duas espécies com maior número de plantas empregadas foram Derris nicou e Denis urucu; seus representantes são provenientes de regiões que foram consideradas como "refúgios florestais", durante o plcistoceno na Amazônia. Dentro de cada espécie, as plantas variaram, desde aquelas ineficientes, até as que foram altamente letais no controle das moscas. Esta capacidade diferencial no controle das larvas entre plantas da mesma espécie, originadas de regiões diferentes, sugere que ambas as espécies devem ter apresentado isolamento de suas populações, durante esta época do quaternário. Nas regiões ou "refúgios florestais", onde essas espécies estiveram representadas, D. urucu foi superior a D. nicou na capacidade de controlar as larvas. Enquanto, entre as plantas da região F (refúgio do Leste-peruano), do Estado do Acre, as duas espécies apresentaram convergência de valores, dos danos produzidos nos agrupamentos de larvas. Entre as outras espécies, Derris sp. (timbó amarelo ou melancia) não apresentou entre as amostras provenientes de duas regiões, diferenças nos efeitos às larvas; enquanto, a espécie introduzida na Amazônia, Derris elliptica, mostrou danos nos agrupamentos de larvas, semelhantes a algumas das melhores plantas de D. nicou e D. urucu.

Teores de rotenona em Clones de Timbó (Derris Spp. Fabaceae) de diferentes regiões da Amazônia e os seus efeitos na emergência de Imagos em Musca Domestica L

A análise dos teores de rotenona, em clones de três espécies de timbó, permitiram a classificação destas plantas de acordo com as suas eficiências no controle de larvas de Musca domestica. Os resultados evidenciaram correlações significativas entre os teores de rotenona apresentados pelos clones de Derris urucu e de Derris nicou, com relação a capacidade de controle das larvas. As plantas com os maiores teores de rotenona foram as mais eficientes. O conteúdo de rotenona, os efeitos dos clones das espécies de Derris nas moscas, além dos locais de origem das plantas, mostraram que deve ter ocorrido entre estes timbós, a existência de isolamento populacional, durante a época do pleistoceno na Amazônia. Em Derris sp., que apresentou menor teor de rotenona, sendo ineficiente no controle das larvas, estas diferenças não foram assinaladas.

Búsqueda de pesticidas naturales aplicables a la producción orgánica: Aislamiento e identificación de principios insecticidas y herbicidas en Flourensia oolepis y Dolichandra cynanchoides y desarrollo de un insecticida natural contra moscas (Musca domestica)

Los productos sintéticos destinados a controlar plagas y enfermedades en los vegetales han tenido un rol muy marcado en el incremento de la producción agrícola, sin embargo el uso continuo e indiscriminado de estas sustancias, ha causado enfermedades, muertes por envenenamiento, ha afectado al medio ambiente acumulándose por bioconcentración en los distintos eslabones de la cadena alimenticia, en el suelo, y en el agua, siendo además responsables de la resistencia de distintas plagas y enfermedades. Bajo estas circunstancias nuevas vías de control de plagas deben ser estudiadas. En los últimos años se está retornando al uso de las plantas como fuente de pesticidas más seguros para el medio ambiente y la salud humana en sustitución de los productos sintéticos. Numerosos componentes del reino vegetal han demostrado ser altamente tóxicos contra un amplio espectro de insectos y microorganismos, lo que puede ser aprovechado para el control de los mismos. A partir de un screening de 28 plantas autóctonas de la zona central de Argentina, hemos seleccionado aquellas más efectivas como son Flourensia oolepis, Dolichandra cynanchoides para el aislamiento bioguiado de sus principios activos con acción insecticida y herbicida. También se buscan sustancias o mezcla de sustancias naturales que controlen moscas (Musca domestica) con el fin de desarrollar un insecticida que sea compatible con la industria alimenticia.

Episodes of insect life / By Acheta Domestica.

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Episodes of insect life / By Acheta Domestica.

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Episodes of insect life / By Acheta Domestica.

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