A Mox homeobox gene in the gastropod mollusc Haliotis rufescens is differentially expressed during larval morphogenesis and metamorphosis

We have isolated a homeobox-containing cDNA from the gastropod mollusc Haliotis rufescens that is most similar to members of the Mox homeobox gene class, The derived Haliotis homeodomain sequence is 85% identical to mouse and frog Mox-2 homeodomains and 88.9% identical to the partial cnidarian cnox5-Hm homeodomain. Quantitative reverse transcription-polymerase chain reaction analysis of mRNA accumulation reveals that this gene, called HruMox, is expressed in the larva, but not in the early embryo, Transcripts are most prevalent during larval morphogenesis from trochophore to veliger. There are also transient increases in transcript prevalence 1 and 3 days after the intitiation of metamorphosis from veliger to juvenile. The identification of a molluscan Mox homeobox gene that is more closely related to vertebrate genes than other protostome (e.g. Drosophila) genes suggests the Mox class of homeobox genes may consist of several different families that have been conserved through evolution, (C) 1997 Federation of European Biochemical Societies.

Carios fonsecai sp nov (Acari, Argasidae), a bat tick from the central-western region of Brazil

Males, females, and larvae of Carios fonsecai sp. nov. are described from free-living ticks collected in a cave at Bonito, state of Mato Grosso do Sul, Brazil. The presence of cheeks and legs with micromammillate cuticle makes adults of C. fonsecai morphologically related to a group of argasid species (mostly bat-associated) formerly classified into the subgenus Alectorobius, genus Ornithodoros. Examination of larvae indicates that C. fonsecai is clearly distinct from most of the previously described Carios species formerly classified into the subgenus Alectorobius, based primarily on its larger body size, dorsal setae number, dorsal plate shape, and hypostomal morphology. On the other hand, the larva of C. fonsecai is most similar to Carios peropteryx, and Carios peruvianus, from which differences in dorsal plate length and width, tarsal setae, and hypostome characteristics are useful for morphological differentiation. The mitochondrial 16S rDNA sequence of C. fonsecai showed to be closest (85-88% identity) to several corresponding sequences of different Carios species available in GenBank. Bats identified as Peropteryx macrotis and Desmodus rotundus were found infested by C. fonsecai larvae in the same cave where the type series was collected. C. fonsecai showed to be aggressive to humans in the laboratory.

Cystic hygroma: characterization by computerized tomography

Lymphangiomas are benign nonencapsulated lesions composed of sequestered noncommunicating lymphoid tissue lined by lymphatic endothelium and are thought to be caused by congenital obstruction of lymphatic drainage. They are subclassified by vessel size, such as the capillary, which is rare and located in subcutaneous tissue, cavernous (located about the mouth and tongue), and cystic (cystic hygromas). The cystic hygromas show a predilection for the neck (75%) and maxilla (20%), and the remaining 5% arise in rare locations such as the mediastinum, retroperitoneum, bone, kidney, colon, liver, spleen and scrotum. Only 3%-10% of neck lesions extend into the mediastinum. In this paper, we report a rare case of cystic hygroma with a huge dimension discussing the use of computed tomography scanning for diagnosis.

Ecological regulation of development: Induction of marine invertebrate metamorphosis

In the marine environment a wide range of invertebrates have a pelagobenthic lifecycle that includes planktonic larval and benthic adult phases. Transition between these morphologically and ecologically distinct phases typically occurs when the developmentally competent larva comes into contact with a species-specific environmental cue. This cue acts as a morphogenetic signal that induces the completion of the postlarval/juvenile/adult developmental program at metamorphosis. The development of competence often occurs hours to days after the larva is morphologically mature. In the non-feeding - lecithotrophic - larvae of the ascidian Herdmania curvata and the gastropod mollusc Haliotis asinina, gene expression patterns in pre-competent and competent stages are markedly different, reflecting the different developmental states of these larval stages. For example, the expression of Hemps, an EGF-like signalling peptide required for the induction of Herdmania metamorphosis, increases in competent larvae. Induction of settlement and metamorphosis results in further changes in developmental gene expression, which apparently is necessary for the complete transformation of the larval body plan into the adult form.

Embryogenesis and metamorphosis in a haplosclerid demosponge: gastrulation and transdifferentiation of larval ciliated cells to choanocytes

Early development and metamorphosis of Reniera sp., a haplosclerid demosponge, have been examined to determine how gastrulation occurs in this species, and whether there is an inversion of the primary germ layers at metamorphosis. Embryogenesis occurs by unequal cleavage of blastomeres to form a solid blastula consisting micro- and macromeres; multipolar migration of the micromeres to the surface of the embryo results in a bi-layered embryo and is interpreted as gastrulation. Polarity of the embryo is determined by the movement of pigment-containing micromeres to one pole of the embryo; this pole later becomes the posterior pole of the swimming larva. The bi-layered larva has a fully differentiated monociliated outer cell layer, and a solid interior of various cell types surrounded by dense collagen. The pigmented cells at the posterior pole give rise to long cilia that are capable of responding to environmental stimuli. Larvae settle on their anterior pole. Fluorescent labeling of the monociliated outer cell layer with a cell-lineage marker (CMFDA) demonstrates that the monociliated cells resorb their cilia, migrate inwards, and transdifferentiate into the choanocytes of the juvenile sponge, and into other amoeboid cells. The development of the flagellated choanocytes and other cells in the juvenile from the monociliated outer layer of this sponge's larva is interpreted as the dedifferentiation of fully differentiated larval cells-a process seen during the metamorphosis of other ciliated invertebrate larvae-not as inversion of the primary germ layers. These results suggest that the sequences of development in this haplosclerid demosponge are not very different than those observed in many cnidarians.

The embryonic development of the bodywall and nervous system of the cestode flatworm Hymenolepis diminuta

Cestodes (tapeworms) are a derived, parasitic clade of the phylum Platyhelminthes (flatworms). The cestode body wall represents an adaptation to its endoparasitic lifestyle. The epidermis forms a nonciliated syncytium, and both muscular and nervous system are reduced. Morphological differences between cestodes and free-living flatworms become apparent already during early embryogenesis. Cestodes have a complex life cycle that begins with an infectious larva, called the oncosphere. In regard to cell number, cestode oncospheres are among the simplest multicellular organisms, containing in the order of 50-100 cells. As part of our continuing effort to analyze embryonic development in flatworms, we describe here the staining pattern obtained with acTub in embryos and larvae of the cestode Hymenolepis diminuta and, briefly, the monogenean Neoheterocotyle rhinobatidis. In addition, we labeled the embryonic musculature of Hymenolepis with phalloidin. In Hymenolepis embryos, two different cell types that we interpret as neurons and epidermal gland cells express acTub. There exist only two neurons that develop close to the midline at the anterior pole of the embryo. The axons of these two neurons project posteriorly into the center of the oncosphere, where they innervate the complex of muscles that is attached to the booklets. In addition to neurons, acTub labels a small and invariant set of epidermal gland cells that develop at superficial positions, anteriorly adjacent to the neurons, in the dorsal midline, and around the posteriorly located hooklets. During late stages of embryogenesis they spread and form a complete covering of the embryo. We discuss these data in the broader context of platyhelminth embryology.

Application of quantitative analytical electron microscopy to the mineral content of insect cuticle

Quantification of calcium in the cuticle of the fly larva Exeretonevra angustifrons was undertaken at the micron scale using wavelength dispersive X-ray microanalysis, analytical standards, and a full matrix correction. Calcium and phosphorus were found to be present in the exoskeleton in a ratio that indicates amorphous calcium phosphate. This was confirmed through electron diffraction of the calcium-containing tissue. Due to the pragmatic difficulties of measuring light elements, it is not uncommon in the field of entomology to neglect the use of matrix corrections when performing microanalysis of bulk insect specimens. To determine, firstly, whether such a strategy affects the outcome and secondly, which matrix correction is preferable, phi-rho (z) and ZAF matrix corrections were contrasted with each other and without matrix correction. The best estimate of the mineral phase was found to be given by using the phi-rho (z) correction. When no correction was made, the ratio of Ca to P fell outside the range for amorphous calcium phosphate, possibly leading to flawed interpretation of the mineral form when used on its own.

Sensitivity of Helicoverpa armigera nucleopolyhedrovirus polyhedra to sodium dodecyl sulfate

Sodium dodecyl sulfate (SDS) is commonly used to extract polyhedra from infected cells and diseased dead larval tissues. It was found, however, that 80% of Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) polyhedra produced via cell culture were damaged after 30 min of 0.5% SDS treatment whereas only 20% of in vivo produced polyhedra were damaged by the same treatment. Transmission and scanning electron microscopy revealed that the damaged polyhedra had lost their polyhedron envelopes and virions were dislodged from the polyhedrin matrix, leaving empty spaces that were previously occupied by the occluded virions. Up to 20% in vitro produced polyhedra were resistant to SDS and remained intact, even after a 24 h exposure to SDS. This sensitivity to SDS was observed across a range of cell culture media, including serum supplemented media. Electron microscopy also revealed that the inferior polyhedron envelope of in vitro produced polyhedra is likely due to poor interaction between the polyhedron envelope, polyhedron envelope protein (PEP), and polyhedrin matrix. The PEP gene was cloned and sequenced and mutations in this gene were ruled out as an explanation. In vitro produced polyhedra that were passed through insect larva once were resistant to SDS, indicating that a critical component is lacking in insect cell culture medium used for producing HaSNPV or the cells growing in culture are inefficient in some ways in relation to production of polyhedra. (C) 2002 Elsevier Science (USA). All rights reserved.

Leaf consumption and duration of instars of the cassava defoliator Erinnyis ello (L., 1758) (Lepidoptera, Sphingidae)

The objectives of this research were to evaluate leaf consumption and the developmental time of the larvae of Erynnyis ello (L., 1758) (Lepidoptera, Sphingidae) reared on cassava, in order to obtain information for the integrated management of this pest. The larvae were reared on excised cassava leaves in Petri dishes and later in gerbox, and kept in chambers at 24 ± 2 ºC and 75 ± 10% RH. The total leaf area consumed by the larva to complete its development was 589.67 cm2; each of the five instars consumed, respectively: 1.89 cm2; 5.74 cm2; 17.48 cm2; 76.66 cm2; and 487.90 cm2. The consumption by the first three instars was insignificant, and did not reach 5% altogether; the 4th represented 13%; the 5th presented a consumption significantly higher, about 82.7%. The total time for the larval development was 22.61 days, and the duration for each of the five larval instar was, respectively: 4.35; 3.19; 3.32; 4.52; and 4.94 days. The pre-pupal period lasted 2.29 days. Since the highest consumption is by the 5th instar larva, the control should be applied before this age to avoid heavier damages to the cassava crop.

Levantamento de moscas-das-frutas e seus parasitoides em citros, no município de Viçosa, Minas Gerais

As moscas-das-frutas são responsáveis por grandes perdas em fruteiras comerciais no Brasil, por isso é fundamental conhecer as espécies predominantes na região. Objetivou-se com este trabalho estudar a ocorrência de moscas-das-frutas (Diptera: Tephritidae) e seus parasitoides em laranjas doces (Citrus sinensis L. Osbeck), tangerina Poncã (Citrus reticulata Blanco) e mexerica Rio (Citrus deliciosa Ten), no município de Viçosa, Minas Gerais. Os frutos foram coletados em abril de 2008. No laboratório eles foram acondicionados em caixas plásticas contendo areia umedecida e em ambiente controlado para obtenção dos pupários, que foram contados, acondicionados em frascos de vidro com areia fina e mantidos em estufa até a emergência dos adultos. Somente uma espécie de mosca-das-frutas (Anastrepha fraterculus (Wiedemann, 1830) e uma de parasitoide (Doryctobracon brasiliensis Szépligeti) foram identificadas. Dentre as variedades, a laranja doce Baianinha apresentou o maior índice de infestação, e os menores foram atribuídos à mexerica Rio e à tangerina Poncã.

Danos de moscas-das-frutas (Diptera, Tephritidae) em citros, manejados no sistema orgânico de produção

As moscas-das-frutas são as principais pragas da fruticultura mundial. Consideradas chaves para a produção de citros, torna-se necessário o seu monitoramento, visando a evitar os danos diretos. O experimento teve como objetivos conhecer a variação populacional de Anastrepha fraterculus e a relação de sua população com danos em pomares orgânicos de Citrus sinensis, cultivar Céu e de C. sinensis x Citrus reticulata tangor 'Murcott'. Os dados foram coletados em 2003 e 2004 durante o período de maturação dos frutos, na região do vale do Caí, RS, Brasil. O número de moscas-das-frutas foi registrado, semanalmente, por meio de armadilhas McPhail, contendo suco de uva, a 25%. Danos aos frutos foram determinados pela razão entre frutos sadios e frutos danificados pela mosca. Registros meteorológicos de temperatura, umidade relativa e precipitação pluviométrica foram obtidos, em estação meteorológica distante 30 km das áreas experimentais. Verificou-se que, em condições ideais de precipitação pluvial, maiores foram as populações de A. fraterculus, espécie predominante na região. A população estimada capaz de causar danos aos frutos variou de acordo com o cultivar, sendo a laranjeira 'Céu' a mais susceptível. Os maiores picos populacionais ocorrem na fase de mudança de coloração dos frutos. Porém, na fase de maturação, as moscas causaram os maiores danos, dada a intolerância dos frutos ao ataque. Conclui-se que a infestação dos frutos de citros por A. fraterculus está relacionada com espécie e cultivar e com fatores climáticos, principalmente com a precipitação pluvial. O monitoramento constante da população de mosca-das-frutas é importante na determinação da infestação na colheita.

Atração de miracídios de Schistosoma mansoni por hospedeiros invertebrados: comportamento de miracídios frente a girinos de Hyla fuscovaria

Analisou-se a atração de miracídios de Schistosoma mansoni das linhagens BH e SJ frente a seus vetores simpátricos e alopátricos tendo-se em consideração a possibilidade da presença de substâncias quimiotáxicas emanadas dos moluscos. Estudou-se também o comportamento desses miracídios frente a girinos de Hyla fuscovaria. Foi verificado que houve atração dos miracídios pelos moluscos vetores e que essa atração foi mais evidente quando a larva era colocada frente ao seu hospedeiro simpátrico.As observações realizadas no decorrer da experiência demonstraram a presença de substâncias miraxonais emanadas pelos moluscos.

Biologia de Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) en la costa Pacífica de Colombia: I. Fluctuación de la población larval y características de sus criaderos

En Charambirá, localidad del município de Istmina (Chocó) en la costa Pacífica de Colombia, donde existe un problema de malaria endémica, se estudió la fluctuación de la población larval y las características de los criaderos de Anopheles (Kerteszia) neivai, especie considerada como posible vectora de malaria en esa región del país. La vegetación circundante fue dividida en tres estratos de acuerdo al grado de cobertura foliar. Se demarcaron cuadrantes de 100 m² en cada estrato para el muestreo de plantas epífitas de la família Bromeliaceae, en las cuales se acumula agua que sirve como criadero para esta especie de anofelino. Se tomaron datos de temperatura, pH y volumen del agua contenida en cada bromelia. El mayor número de larvas se detectó en el estrato 1 (manglar) a una altitud inferior a 4 m, pero no se encontró evidencia significativa de estratificación vertical de la población larval de A. neivai hasta los 8 m. Se evidenció una correlación lineal positiva entre el número de larvas y el volumen de agua contenida en cada bromelia; por otra parte se observó también una correlación directa entre la precipitación mensual acumulada y la fluctuación poblacional de esta especie. Los índices larvales mas altos se observaron entre los meses de marzo a abril y de julio a agosto. La mortalidad larval fue alta en el primer estadío (43,5%) y solo un 23,7% sobrevivió hasta el cuarto.

Verificação de antagonismo entre larvas de Schistosoma mansoni e larvas de outros Digenea em Biomphalaria tenagophila, molusco planobídeo de criadouro natural situado na região de Campinas, SP, Brasil

Foi observado o comportamento de larvas de S. mansoni em moluscos prévia e naturalmente infectados por larvas de outros Digenea. Foi verificado que as larvas de S. mansoni não se desenvolveram nos moluscos previamente infectados com purcocercárias longifurcadas com ocelos ou com furcocercárias longifurcadas sem ocelos. Observou-se resistência parcial ao desenvolvimento de S. mansoni nos moluscos previamente infectados por equinostomocercárias ou por distomocercárias com acúleo. A ausência de reação amebocitária em torno dos esporocistos de S. mansoni nos moluscos infectados por outros digenéticos parece indicar a não participação dos amebócitos na resistência oferecida ao desenvolvimento das larvas de S. mansoni.

Tres especies nuevas de Simulium Latreille de la región Neotropical: Simulium (Hemicnetha) cristalinum sp.n., (Grenieriella) wygodzinskyorum sp.n. y sumapazense sp.n. (Diptera, Simuliidae)

Tres especies nuevas son descriptas: Simulium (Hemicnetha) crisatalinum proveniente de Roraima, Brasil (hembra, macho, pupa y larva; pertenciente al el grupo brachycladum); (Grenieriella) wygodzinskyorum de Junin, Perú (hembra, macho, pupa y larva; pertenciente al el grupo lahillei); (Grenieriella) sumapazense proveniente de Cundinamarca, Colombia y descripta con base en la pupa y parte del macho.