Secretory activity and endocrine regulation of male accessory glands in the blood-sucking bug Panstrongylus megistus (Hemiptera: Reduviidae)

The epithelial cells of Panstrongylus megistus male accessory glands (MAG) present ultrastructural characteristics of a secretory cell. Their secretory products are accumulated in the lumen of the four MAG lobes. During the first 8 days of adult life a strong secretion activity occurs, accumulating enough material to produce the first spermatophore. Cerebral neurosecretions as well as juvenile hormone are both involved in MAG secretory activity regulation. Juvenile hormone seems to be the responsible for the stimulation of most protein synthesis in male accessory glands. Cerebral neurosecretion seems to be necessary to stimulate juvenile hormone production and release by the corpus allatum. Furthermore, neurosecretion is required for some polypeptides synthesis by MAG. Although topic application of precocene II to adult males does not reproduce the same effects on MAG as does allatectomy, this compound causes strong reduction on male reproductive capacity.

The vitellogenin gene family of Aedes aegypti

We have been interested in identifying genes that play a role in reproduction of the mosquito Aedes aegypti. Our interests are currently focused on the vitellogenin genes which in the mosquito are expressed only in the fat body in response to the insect steroid hormone, 20-hydroxyecdysone. Four of the five vitellogenin genes in the genome have been cloned. We have examined the relationships between these genes and find that they form a small gene family exhibiting different levels of relationship.

From a mono to a digenetic life-cycle: how was the jump for flagellates of the family trypanosomatidae?

It has been found that species of the digenetic genus Trypanosoma as well as species of monogenetic trypanosomatids of insects can grow in the lumen of the scent glands of opossums reproducing the cycle they perform in the intestinal tract of their insect hosts. Based on these findings, speculations are made on the incompletely known cycles of many mammalian trypanosomes and on the evolution of the family Trypanosomatidae.

Studies on male genitalia of sarcophagidae (Diptera) based on scanning electron microscope observations

Male genitalia of Oxyvinia exicisa (Lopes), Oxysarcodexia thomax (Walker), O. fluminensis Lopes, Sarcodexia lambens (Wiedemann), Peckia chrysostoma (Wiedemann) and Liopygia ruficornis (Fabricius) were studied based on scanning electron microscope photography. Some important details were evidentiated with this method.

Scanning electron microscopy of the male genitalia of Sarcophagidae (Diptera)

The male genitalia of nine species of Sarcophagidae (Diptera) - Goniophyto honsuensis Rohdendorf, 1962, Tricharaea brevicornis (Wiedemann, 1830), Chaetoravinia derelicta (Walker, 1852), Austrohartigia spinigena (Rondani, 1864), Chrysagria duodecimpunctata Townsend, 1935, Boettcheria bisetosa Parker, 1914, Lipoptilocnema lanei Townsend, 1934, L. crispina (Lopes, 1938) and Euboettcheria alvarengai Lopes & Tibana, 1982 - were examined by scanning electron microscope (SEM) and the main morphological features are descirbed.

Notes on the male genitalia of species of Ravinia and Chaetoravinia (Diptera: Sarcophagidae)

Based on scanning electron microscope (SEM) estudies, the male genitalia of three species of Ravinia and two species of Chaetoravinia (Diptera: Sarcophagidae, subtribe Raviniina) are described and compared.

Screening of the antimalarial activity of plants of the Cucurbitaceae family

Crude ethanolic extracts (CEEs) from two species of Cucurbitaceae, Cucurbita maxima and Momordica charantia (commonly called "abóbora moranga" and melão de São Caetano", respectively) were assayed for antimalarial activity by the 4-d suppressive test. The CEE of dry C. maxima seeds showed strong antimalarial activity following oral administration (259 and 500 mg/kg), reducing by 50% the levels of parasistemia in Plasmodium berghey-infected mice. Treatment of normal animals with 500 mg/Kg of the extract three days before intravenous injection of P. berghei caused a significant 30% reduction in parasitemic levels. No effect was observed when the animals were treated with the CEE only on the day of inoculation. Oral administration of the CEE of dry M. charantia leaves adminstered orally was ineffective up to 500 mg/Kg in lowering the parasitemic levels of malarious mice.

Neoparaseuratum travasssosi, n. g., n. sp. (Nematoda: Quimperiidae), a new parasite from thorny catfish Pterododas granulosus in Brazil

A new nematode genus and species. Neoparaseuratum travassosi n. g., n. sp., is described from the intestine of the freshwater thorny catfish, Pterodoras granulosus (Valenciennes), from the Paraná River, Brazil. This seuratoid nematode species represents a new genus of the family Quimperiidae, being characterized mainly by the presence of numerous narrow longitudinal bands of inflated cuticle extending along the cephalic region of the body, small deirids, postoesophageal position of the excretory pore, relatively short (0.159-0.303 mm), equal spicules and a gubernaculum, the absence of caudal alae and preanal sucker in the male, and by some other features.

On some family related parasites (Nematoda, Cucullanidae) from the marine fish Paralonchurus brasiliensis (Steindachner, 1875) (Pisces, Ostraciidae)

Dichelyne (Cucullanellus) elongatus (Tornquist, 1931) Petter, 1974 and Cucullanus pulcherrimus Barreto, 1918, from Paralonchurus brasiliensis (Steind., 1875) are redescribed and two specimens of Dichelyne (Cucullanellus) sp. are also reported in this host, despite lack of previously, was again identified in Brazil since its original description and posterior illustration. The present findings represent also a new host record for the referred genera: Dichelyne Jagerskiold, 1902 and Cucullanus Mueller, 1777. D. (C.) elongatus is also referred in Brazil for the first time.

Characterization of a Plasmodium falciparum mutant that has deleted the majority of the gametocyte-specific Pf11-1 locus

We identified a gametocyte-specific protein of Plasmodium falciparum called Pf11-1 and provide experimental evidence that this molecule is involved in the emergence of gametes of the infected erythrocyte (gametogenesis). A mutant parasite clone, which has deleted over 90% of the PF11-1 gene locus, was an important control to establish the gametocyte-specific expression of the Pf11-1. Molecular analysis of the Pf11-1 deletion indicates that it is presumably due a chromosome breakage with subsequent "healing" by the addition of telomeric heptanucleotides. Moreover, similar DNA rearrangements are observed in most of the laboratory isolates during asexual propagation in vitro.

Structure of the salivary glands of the unfed male tick Amblyomma cajennense (Fabricius) (Acarina: Ixodidae)

Acini in the salivary glands of unfed male Amblyomma cajennense of different ages, were studied. The salivary glands consist of one agranular and three granular acini types. The agranular acini are directly attached to the medial and anterior portion of the main salivary duct, and to some branches of the secondary ducts. A large, clear, central cell occupies the centre and this cell is in contact with the acinar lumen. There is no valve to the lumen. Granular acini consist of approximately six to fourteen cells (type II acini) or eight to thirteen (type III acini). The type II acini have three types of granular cells ("a", "b" and "c") and a valve: the type III acini have three types of granular cells ("d", "e" and "f" and a valve.

Re-description of Trypanosoma corvi Stephens and Christophers,1908 Emend. Baker, 1976 and remarks on the Trypanosomes of the Avian Family Corvidae

The trypomastigote, epimastigote and amastigote stages of Trypanosoma corvi Stephens and Christophers, 1908 emend. Baker, 1976 from the peripheral blood, heart and bone marrow are described herein. Other trypanosomes described from the Corvidae are compared to T. corvi and their status is discussed.

Thevetia peruviana (Family: Apocynaceae) in the control of slug and snail pests

An aqueous extract prepared from Kernels of the fruit of Thevetia peruviana (Pers.) Schumann (Family : Apocynaceae) was found under experimental conditions, to be toxic ti the slug Laevicaulis alte (Férussac) and the snail Achatina fulica Bowdich, the important agrihorticultural pests of Indo-Pacific countries. Concentrations as low as 1% (w/v) killed all the slugs exposed in less than 981.00 (± SD 22.76) min, and 2% of the extract killed 100% of the slugs L. alte and 50%, 50% and 30% of the snail A. fulica in between 92.34 (± SD 6.63) - 321.33 (± SD 4.14) and 271.20 (± SD 17.54) - 298.26 (± SD 16.69) min respectively. The most effective concentration of the extract was 20%; it killed 100% of exposed slugs and snails within a short time (40-50 and 90-1440 min respectively) when the extract was exposed on the soil in experimental trays or when it was applied to potato slices offered as food to the gastropods.

Host-induced morphological changes of Schistosoma mansoni Sambon, 1907 male worms

In order to evaluate the permissiveness of Nectomys squamipes to Schistosoma mansoni and the influence of the albino mice on the morphological aspects of adult worms derived from a population isolated from N. squamipes, the morphology of adult S. mansoni Sambon, 1907 male worms was studied using a digital image analyser (MOP VIDEOPLAN) and light microscopy. Their sources were as follows: (1) recovered from the wild rodent N. squamipes Brants naturally infected from Sumidouro, RJ, Brazil; (2) recovered from albino mice experimentally infected with the strain derived from N. squamipes; (3) recovered after the isolation of a strain derived from aboriginal human infections in Sumidouro. Worms recovered from N. squamipes (group 1) showed body lenght and distance between suckers significantly bigger than those of the specimens maintained in mice (groups 2 and 3). The number of tests in group 1 was statistically less than of groups 2 and 3. Group 2 strains which were maintained in mice, presented the lenght of the worms as the only significant different character. Data show that: (1) N. squamipes is a more suitable host for the development of S. mansoni when compared to the albino mice; (2) a strain of S. mansoni isolated from a natural host undergoes morphological changes after its passage in the white mouse.