Angiogenesis and schistosomiasis

Angiogenesis has been recognised as a precursor of fibrosis in several pathologic conditions. Its participation has been demonstrated in schistosomiasis, both during periovular granuloma formation and in the genesis of schistosomal periportal fibrosis. Paradoxically, proliferation of new blood vessels, accompanied by production of vascular-endothelial growth factor, appeared prominent during fibrosis regression months after curative treatment of schistosomiasis. Thus, angiogenesis in schistosomiasis seems to have a two-way mode of action, participating both in fibrogenesis and in fibrosis degradation. Morphological observations presented here are in keeping with the possibility that, in the first case, angiogenesis allows pericytes to come in great numbers to the site of lesions and be detached from capillary walls and transformed into myofibroblasts, which are important extra-cellular matrix forming cells. During post-curative fibrosis regression, actin-containing pericytes appeared at various foci of tissue remodelling, especially at sites of repair of vascular lesions. The molecular and cell factors involved in both situations seem to be important subjects in need of further investigations and the schistosomiasis model certainly will be of great avail in this regard.

Angiogenesis and experimental hepatic fibrosis

Angiogenesis is a basic change occurring during repair by granulation tissue. This process seems to precede fibrosis formation in most types of chronic liver disease. To examine its presence and significance in different types of hepatic insults, this paper sought to identify the presence, evolution and peculiarities of angiogenesis in the most common experimental models of hepatic fibrosis. The characterization of cells, vessels and extracellular matrix and the identification of factors associated with endothelium (factor VIII RA), vascular basement membrane, other components of the vascular walls (actin, elastin) and the presence of the vascular-endothelial growth factor were investigated. The models examined included Capillaria hepatica septal fibrosis, whole pig serum injections, carbon tetrachloride administration, main bile duct ligation and Schistosoma mansoni infection. The first four models were performed in rats, while the last used mice. All models studied exhibited prominent angiogenesis. The most evident relationship between angiogenesis and fibrosis occurred with the C. hepatica model due to circumstances to be discussed. Special attention was paid to the presence of pericytes and to their tendency to become detached from the vascular wall and be transformed into myofibroblasts, which is a sequence of events that explains the decisive role angiogenesis plays in fibrosis.

Residual effect of a micro-encapsulated formulation of organophosphates and piriproxifen on the mortality of deltamethrin resistant Triatoma infestans populations in rural houses of the Bolivian Chaco region

The Bolivian Chaco is part of the endemic region of Chagas disease and an area where pyrethroid resistant Triatoma infestans (Hemiptera: Reduviidae) populations has been reported. The World Health Organization identified these resistant populations as an important focus for research. The objective of this study was to evaluate the residual effect of a micro-encapsulated formulation containing organophosphate active ingredients and a juvenile hormone analogue (Inesfly 5A IGR) on the mortality of T. infestans. Studies took place in rural houses of the Bolivian Chaco that were treated up to 34 months before and evaluated the susceptibility to pyrethroids of the offspring of field collected insects. Thirty houses were randomly selected within three communities to carry out wall bio-assays with T. infestans nymphs. Mortality was recorded 24, 48 and 72 h after wall contact. Eggs laid by females collected in the area were used to obtain first-instar nymphs and carry out pyrethroid susceptibility tests. The wall bio-assays showed that the micro-encapsulated insecticide eliminates T. infestans populations and produces detectable mortality of insects exposed to walls treated 34 months prior to the tests. The discriminant dose of deltamethrin (0.01 mg/mL) showed 65% nymph survival, whereas at the highest tested dose (1.0 mg/mL) 14% of the nymphs survived. These results show that Inesfly 5A IGR is an appropriate tool for the elimination of intradomestic and peridomestic populations of T. infestans resistant to pyrethroids.

Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth

We assessed fluconazole susceptibility in 52 Candida tropicalis clinical strains using seven antifungal susceptibility methods, including broth microdilution (BMD) [standard M27 A3 (with neutral and acid pH), ATB Fungus 3, Vitek 2 system and flow cytometric analysis] and agar-based methods (disk diffusion and E-test). Trailing growth, detection of cell-associated secreted aspartic proteases (Saps) and morphological and ultrastructural traits of these clinical strains were also examined. The ranges of fluconazole 24 h-minimum inhibitory concentration (MIC) values were similar among all methods. The essential agreement among the methods used for MIC determinations was excellent and all methods categorised all strains as susceptible, except for one strain that showed a minor error. The presence of the trailing effect was assessed by six methods. Trailing positivity was observed for 86.5-100% of the strains. The exception was the BMD-Ac method where trailing growth was not observed. Morphological and ultrastructural alterations were detected in C. tropicalis trailing cells, including mitochondrial swelling and cell walls with irregular shapes. We tested the production of Saps in 13 C. tropicalis strains expressing trailing growth through flow cytometry. Our results showed that all of the C. tropicalis strains up-regulated surface Sap expression after 24 h or 48 h of exposure to fluconazole, which was not observed in untreated yeast strains. We concluded that C. tropicalis strains expressing trailing growth presented some particular features on both biological and ultrastructural levels.

Positive deviance study to inform a Chagas disease control program in southern Ecuador

Chagas disease is caused by Trypanosoma cruzi, which is mainly transmitted by the faeces of triatomine insects that find favourable environments in poorly constructed houses. Previous studies have documented persistent triatomine infestation in houses in the province of Loja in southern Ecuador despite repeated insecticide and educational interventions. We aim to develop a sustainable strategy for the interruption of Chagas disease transmission by promoting living environments that are designed to prevent colonisation of rural houses by triatomines. This study used positive deviance to inform the design of an anti-triatomine prototype house by identifying knowledge, attitudes and practices used by families that have remained triatomine-free (2010-2012). Positive deviants reported practices that included maintenance of structural elements of the house, fumigation of dwellings and animal shelters, sweeping with "insect repellent" plants and relocation of domestic animals away from the house, among others. Participants favoured construction materials that do not drastically differ from those currently used (adobe walls and tile roofs). They also expressed their belief in a clear connection between a clean house and health. The family's economic dynamics affect space use and must be considered in the prototype's design. Overall, the results indicate a positive climate for the introduction of housing improvements as a protective measure against Chagas disease in this region.

Biologia de Neotrioza tavaresi Crawford, 1925 (Hemiptera, Psyllidae), galhador da folha do araçazeiro (Psidium cattleianum)

Biology of the leaf gall inducer Neotrioza tavaresi Crawford, 1925 (Hemiptera, Psyllidae) on strawberry guava tree (Psidium cattleianum). A field study was conducted in Curitiba region, State of Paraná, southern Brazil, to describe the life cycle of Neotrioza tavaresi Crawford, 1925, a leaf galling insect in strawberry guava trees (Psidium cattleianum). Three cycles were observed (1997, 1998, 1999) during regular field trips and the insects were observed in Piraquara municipality, where 15 samples with 50 infested leaves were sampled in the 1997-98 cycle. Galls were dissected for detailed studies. Neotrioza tavaresi has a univoltine cycle in which adult individuals were found inside the galls from August onwards. The sexually mature insects with sex ratio 1, emerged from the galls after their dehiscence caused by feeding of the adult insects on the gall walls. Adult emergence started in early October and ended by early December, with its peak in November. Copulation took place as soon as adults exit the gall and egg laying started the next day. Females had more than 100 ovarioles containing 218.7±44.7 (n=50) fully formed eggs. This indicated the short sexual adult life-span (aprox. 5-7 days) of the species, also characterized by a concentrated oviposition. Adult individuals fed and laid their eggs on younger shoots of the plant. The bottoms of the yellowish eggs were inserted into the leaf tissue, mainly on its adaxial edge (78.1%). The nymphs hatched and, as they fed on the adaxial side of expanding leaves, modified the cell growth pattern and the round-shape galls developed on the adaxial side with one insect inside. The gall wall showed distinct layers, with the inner one suppliyng the food to the insects, and the outer layer supplying gall protection. Nymphs went through five instars and the exuviae remained stuck on a ball of wax inside the gall. All parasitoids found were Hymenoptera belonging to Chalcidoidea: Eulophidae (1 sp), Pteromalidae (2 spp) and Encyrtidae (3 spp). The findings suggest that leaf gall inducer and parasitoids insects and plant life cycles are closely connected and both leaf sprouting and gall opening seem to be triggered by the same environmental and plant conditions. The high abundance of shoots may favor insect performance as adult individuals can easily find an ideal place for feeding, copulating and laying eggs.

Meliponini neotropicais: o gênero Partamona Schwarz, 1939 (Hymenoptera, Apidae, Apinae) - bionomia e biogeografia

This work, dedicated to the study of nesting habits of the species of the Neotropical genus Partamona Schwarz, is a sequence to the taxonomic revision recently published elsewhere. A total of 214 nests and nest aggregations of 18 species [Partamona epiphytophila Pedro & Camargo, 2003; P. testacea (Klug, 1807); P. mourei Camargo, 1980; P. vicina Camargo, 1980; P. auripennis Pedro & Camargo, 2003; P. combinata Pedro & Camargo, 2003; P. chapadicola Pedro & Camargo, 2003; P. nhambiquara Pedro & Camargo, 2003; P. ferreirai Pedro & Camargo, 2003; P. pearsoni (Schwarz, 1938); P. gregaria Pedro & Camargo, 2003; P. batesi Pedro & Camargo, 2003; P. ailyae Camargo, 1980; P. cupira (Smith, 1863); P. mulata Moure in Camargo, 1980; P. seridoensis Pedro & Camargo, 2003; P. criptica Pedro & Camargo, 2003; P. helleri (Friese, 1900)] were studied , including data about habitat, substrate, structural characteristics, construction materials and behavior. The descriptions of the nests are illustrated with 48 drawings. Partial data of the nests of P. bilineata (Say, 1837), P. xanthogastra Pedro & Camargo, 1997, P. orizabaensis (Strand, 1919), P. peckolti (Friese, 1901), P. aequatoriana Camargo, 1980, P. musarum (Cockerell, 1917) and P. rustica Pedro & Camargo, 2003 are also presented. Nests of P. grandipennis (Schwarz, 1951), P. yungarum Pedro & Camargo, 2003, P. subtilis Pedro & Camargo, 2003, P. vitae Pedro & Camargo, 2003, P. nigrior (Cockerell, 1925), P. sooretamae Pedro & Camargo, 2003 and P. littoralis Pedro & Camargo, 2003 are unknown. The species of Partamona build notable nest entrance structures, with special surfaces for incoming / exiting bees; some of them are extremely well-elaborated and ornamented, serving as flight orientation targets. All species endemic to western Ecuador to Mexico with known nesting habits (P. orizabaensis, P. peckolti, P. xanthogastra, P. bilineata, P. aequatoriana and P. musarum) build their nests in several substrates, non-associated with termitaria, such as cavities and crevices in walls, among roots of epiphytes and in bases of palm leaves, in abandoned bird nests, under bridges, and in other protected places, except P. peckolti that occasionally occupies termite nests. In South America, on the eastern side of the Andes, only P. epiphytophila and P. helleri nest among roots of epiphytes and other substrates, non-associated with termitaria. All other species studied (P. batesi, P. gregaria, P. pearsoni, P. ferreirai, P. chapadicola, P. nhambiquara, P. vicina, P. mourei, P. auripennis, P. combinata, P. cupira, P. mulata, P. ailyae, P. seridoensis, P. criptica and P. rustica) nest inside active termite nests, whether epigeous or arboreous. The only species that builds obligate subterranean nests, associated or not with termite or ant nests (Atta spp.) is P. testacea. Nests of Partamona have one vestibular chamber (autapomorphic for the genus) closely adjacent to the entrance, filled with a labyrinth of anastomosing pillars and connectives, made of earth and resins. One principal chamber exists for food and brood, but in some species one or more additional chambers are filled with food storage pots. In nests of P. vicina, there is one atrium or "false nest", between the vestibule and the brood chamber, which contains involucral sheaths, cells and empty pots. All structures of the nest are supported by permanent pillars made of earth and resins (another autapomorphy of the genus). The characters concerning nesting habits were coded and combined with morphological and biogeographic data, in order to hypothesize the evolutive scenario of the genus using cladistic methodology. The phylogenetic hypothesis presented is the following: (((((P. bilineata (P. grandipennis, P. xanthogastra)) (P. orizabaensis, P. peckolti)) (P. aequatoriana, P. musarum)) P. epiphytophila, P. yungarum, P. subtilis, P. vitae) (((((P. testacea (P. mourei, P. vicina)) (P. nigrior (P. auripennis, P. combinata))) (P. ferreirai (P. pearsoni (P. gregaria (P. batesi (P. chapadicola, P. nhambiquara)))))) ((((P. ailyae, P. sooretamae) P. cupira, P. mulata) P. seridoensis) P. criptica, P. rustica, P. littoralis)) P. helleri))). One area cladogram is presented. Dates of some vicariance / cladogenesis events are suggested. For bilineata / epiphytophila group, which inhabits the Southwestern Amazonia and the Chocó-Mexican biogeographical components, the origin of ancestral species is attributed to the Middle Miocene, when the transgressions of the Maracaibo and Paranense seas isolated the tropical northwestern South America from the eastern continental land mass. The next cladogenic event in the history of the bilineata / epiphytophila group is attributed to the Plio-Pleistocene, when the Ecuadorian Andes reached more than 3000 m, and the ancestral species was fragmented in two populations, one occupying the western Andes (ancestral species of the bilineata subgroup) and other the southwestern Amazon (ancestral species of the epiphytophila subgroup). Other aspects of the history of Partamona are also discussed.

Phlebotomines (Diptera, Psychodidae) in the Ribeira Valley Speleological Province - 1. Parque Estadual Intervales, state of São Paulo, Brazil

The identification of the sandfly fauna and investigation of some ecological aspects of its populations in areas frequented by tourists of the PEI, an Atlantic forest reserve with many caves, were the objective of this study. Captures were undertaken monthly from January 2001 to December 2002, with automatic light traps installed in 13 ecotopes, including caves, forests, domiciliary and peridomiciliary environments, and by aspiration in armadillo burrows. Additionally, although not at regular intervals, Shannon traps were installed in forests and anthropic environments, aspirations were made on cave walls, among roots and fallen leaves, and some insects were captured while biting researchers. A total of 891 sandflies belonging to 21 species were captured. Six hundred specimens representing 19 species were captured with light traps, 215 in anthropic (2.24 insects/trap) and 385 in extra-domiciliary (1.46 insects/trap) environments. Brumptomyia troglodytes was the most abundant species (the Standardised Index of Species Abundance = 0.705). Pintomyia monticola predominated in the Shannon traps and showed anthropophilic and diurnal activity. Psathyromyia pascalei predominated in the aspirations; the largest number being in armadillo burrows. Eleven species were captured in caves; although some might be troglophiles, the majority used these ecotopes as resting places. Nyssomyia intermedia, Nyssomyia neivai and Migonemyia migonei, implicated in the transmission of cutaneous leishmaniasis in the Southeastern Brazilian region, were all found, though in such low densities as to suggest minimal risk of the disease in the PEI.

Coffee leaf and stem anatomy under boron deficiency

Boron deficiency in coffee is widely spread in Brazilian plantations, but responses to B fertilizer have been erratic, depending on the year, form and time of application and B source. A better understanding of the effects of B on plant physiology and anatomy is important to establish a rational fertilization program since B translocation within the plant may be affected by plant anatomy. In this experiment, coffee plantlets of two varieties were grown in nutrient solutions with B levels of 0.0 (deficient), 5.0 µM (adequate) and 25.0 µM (high). At the first symptoms of deficiency, leaves were evaluated, the cell walls separated and assessed for B and Ca concentrations. Scanning electron micrographs were taken of cuts of young leaves and branch tips. The response of both coffee varieties to B was similar and toxicity symptoms were not observed. Boron concentrations in the cell walls increased with B solution while Ca concentrations were unaffected. The Ca/B ratio decreased with the increase of B in the nutrient solution. In deficiency of B, vascular tissues were disorganized and xylem walls thinner. B-deficient leaves had fewer and deformed stomata.

Deficiency symptoms and uptake of micronutrients by castor bean grown in nutrient solution

Castor bean is a nutrient-demanding species, but there is still little information on its micronutrient requirements. The objectives of this study were to evaluate the effects of levels of B (2.5, 12.5 and 25.0 µmol L-1), Cu (0.05, 0.25 and 0.50 µmol L-1), Mn (0.2, 1.0 and 2.0 µmol L-1) and Zn (0.2, 1.0 and 2.0 µmol L-1) in a nutrient solution on plant B, Cu, Mn and Zn concentrations and uptake, vegetative growth and fruit yield of castor bean "Iris", grown in greenhouse. The experiment was arranged in a completely randomized block design with three replicates. The first deficiency symptoms were observed for B, followed by Zn, Cu and Mn. The main changes in the cell ultrastructure due to lack of B were thickening of the cell walls and middle lamellae, distorted chloroplasts and tightly stacked thylakoids, besides the absence of starch grains. The Mn, Zn and Cu deficiencies led to disruption of chloroplasts, disintegration of thylakoids and absence of amyloplasts. The concentration and uptake of B, Cu, Mn, and Zn in castor bean plants increased with micronutrient supply in the solution. Fruit yield was drastically reduced by B and Mn deficiencies. On the other hand, the dry matter yield of the shoot and root of castor bean plants was not. In the treatment with full nutrient solution, the leaves accumulated 56 and 48 % of the total B and Mn taken up by the plants, respectively, and the seeds and roots 85 and 61 % of the total Cu and Zn taken up, respectively. This shows the high demand of castor bean Iris for B and Mn for fruit yield.

Aluminum in corn plants: influence on growth and morpho-anatomy of root and leaf

Aluminum (Al) toxicity is one of the most limiting factors for productivity. This research was carried out to assess the influence of Al nutrient solution on plant height, dry weight and morphoanatomical alterations in corn (Zea mays L.) roots and leaves. The experiment was conducted in a greenhouse with five treatments consisting of Al doses (0, 25, 75, 150, and 300 µmol L-1) and six replications. The solutions were constantly aerated, and the pH was initially adjusted to 4.3. The shoot dry matter, root dry matter and plant height decreased significantly with increasing Al concentrations. Compared to the control plants, it was observed that the root growth of corn plants in Al solutions was inhibited, there were fewer lateral roots and the development of the root system reduced. The leaf anatomy of plants grown in solutions containing 75 and 300 µmol L-1 Al differed in few aspects from the control plants. The leaf sheaths of the plants exposed to Al had a uniseriate epidermis coated with a thin cuticle layer, and the cells of both the epidermis and the cortex were less developed. In the vascular bundle, the metaxylem and protoxylem had no secondary walls, and the diameter of both was much smaller than of the control plants.

INTERNAL STRUCTURE OF A VERMICULAR IRONSTONE AS DETERMINED BY X-RAY COMPUTED TOMOGRAPHY SCANNING

Ironstones or petroplinthites are common materials in soils under humid tropical climate, generally defined as the result of Fe oxide accumulation in areas where the water table oscillates, and may exhibit considerable morphological variability. The aim of this study was to examine the internal structure and porosity of an ironstone fragment from a Petroferric Acrudox in Minas Gerais, Brazil, by computed tomography (CT) and conventional techniques. The sample analyzed had total porosity of 59.5 %, with large macropores in the form of tubular channels and irregular vughs, the latter with variable degrees of infilling by material released from the ironstone walls or the soil matrix. The CT scan also showed that the ironstone has wide variation in the density of the solid phase, most likely due to higher concentrations or thick intergrowths of hematite and magnetite/maghemite, especially in its outer rims. The implications of these results for water retention and soil formation in ironstone environments are briefly discussed.

Adaptações em forno de microondas doméstico para utilização em laboratório

Domestic microwave oven was modified for laboratory applications. Electronic system was made for controlling magnetron irradiation time. Exhaustion and air circulation systems were installed to clean the internal oven atmosphere during operation. The cavity walls were coated with aluminized thermal paint to avoid chemical corrosion. These modifications allowed the usage of the oven for drying and processes using reflux.

Desenvolvimento e caracterização de recobrimentos de Ni-Co e de seus óxidos mistos para a produção de oxigênio por eletrólise alcalina da água

This paper describes the development and characterisation of Ni-Co coatings to be used as anodes in water electrolysis. Chemical oxidation of the surface was performed through thermal treatment at 400ºC for 10 h. The resulting surfaces were analysed by X-ray diffraction, EDX, SEM, cyclic voltammetry and constant current electrolysis. The electrochemical oxidation occurring on bare surfaces during electrolysis promotes the formation of thick oxide layers resulting in loss of activity. In oxidised surfaces the chemical Ni-Co oxide grown during the thermal treatment prevents further oxidation thus retaining their activity towards oxygen evolution. An optimum condition for the growth of mixed oxide with high activity was found for the bath containing 50 g L-1 CoSO4.

A química dos liquens

Lichens are symbiotic associations between fungi and algae and/or cyanobacteria. They produce common intracellular products including proteins, amino acids, polyols, carotenoids, polysaccharides and vitamins. The secondary metabolites found in lichens are phenolics which accumulate either on the cortex or on the cell walls of medullary hyphae and they are mainly acetyl-polimalonyl pathway derivatives. Polysaccharides, proteins and secondary metabolites produced by lichens have attracted the attention of investigators due their biological activities. This revision coments about the biosynthetic origin and structures of the principal classes of compounds produced by these organisms.