Testicular Structure and Seminal Pathway in the Yellowtail Tetra Astyanax altiparanae (Characiforms: Characidae).

This study aimed to describe testicular and its main ducts structure in the yellowtail tetra Astyanax altiparanae, contributing to the knowledge of the region in which semen is produced, storage and released, focusing mainly on the dynamic of germinal epithelium and Sertoli cells during germ cell maturation. Ten sexually mature male A. altiparanae had their testes processed according to the routine protocols to optical microscopy. Moreover, spermatic ducts and tubular compartment of the testes of three specimens were perfused with vinyl resin for gross anatomy and scanning electron microscopy. Astyanax altiparanae testes are paired organs, separated for most of their extension, joining posteriorly in a spermatic duct formed by a squamous simple epithelium. Seminiferous compartment presents anastomosing tubular type organisation, and spermatogonia spread along its extent. Spermatogenesis is of cystic type, and there is no main testicular duct. Spermatogenesis develops in 'waves', from posterior to anterior part of the gonad. Thus, while sperm is storage posteriorly, spermatogenesis keeps maturing germ cells anteriorly, making the germinal epithelium very dynamic, holding Sertoli cells that change their function as a cystic envelope to produce secretions of the seminal fluid and store sperm. Such kind of development is thought to be responsible by the high prolificacy of this species.

A study of Culicoides in Rondônia, in the Brazilian Amazon: species composition, relative abundance and potential vectors.

There is very little information available about Culicoides species (Diptera: Ceratopogonidae) in the western Brazilian Amazon. However, studies of the fauna of this region are essential to knowledge of the species and potential vectors within it. Thus, the present study aims to evaluate the abundance, richness and composition of Culicoides species in rural areas in the state of Rondônia, Brazil. Culicoides specimens were collected in forest and pasture environments in the municipality of Porto Velho, using light traps. A total of 1708 individuals (1136 females and 572 males) belonging to 33 species were collected; 28 of these samples represent new records for the state of Rondônia and include the first record of Culicoides contubernalis in Brazil. Culicoides insignis was the most abundant species (86.1%). Species richness was greater in forest areas (32 species, 96.96%), whereas pastures presented the greatest number of Culicoides captured (n = 1540, 90.1%). This study shows that Culicoides populations differ between forest and pasture environments and indicates that the abundance of C. insignis is an important factor in epidemiological vigilance studies in the region.

An in situ atomic force microscope for normal-incidence nanofocus X-ray experiments.

A compact high-speed X-ray atomic force microscope has been developed for in situ use in normal-incidence X-ray experiments on synchrotron beamlines, allowing for simultaneous characterization of samples in direct space with nanometric lateral resolution while employing nanofocused X-ray beams. In the present work the instrument is used to observe radiation damage effects produced by an intense X-ray nanobeam on a semiconducting organic thin film. The formation of micrometric holes induced by the beam occurring on a timescale of seconds is characterized.

Intestinal microbiota and allergic diseases: A systematic review.

Evidence suggests that possible imbalances in intestinal microbiota composition may be implicated in the occurrence of allergic diseases. Although several studies published until 2006 indicated a correlation between microbiota composition and allergic symptoms, it has not been possible to distinguish protective microorganisms from those associated with increased risk of allergic diseases. Therefore, the objective of this study was to review the studies published since 2007 that address the intestinal microbiota in allergic diseases. Twenty-one studies were identified after excluding those that performed a clinical intervention before stool collection. In the early microbiota of children who later developed allergies, lower bacterial diversity was observed, with a predominance of Firmicutes; a higher count of Bacteroidaceae; a higher prevalence of the anaerobic bacteria Bacteroides fragilis, Escherichia coli, Clostridium difficile, Bifidobacterium catenulatum, Bifidobacterium bifidum, and Bifidobacterium longum; and a lower prevalence of Bifidobacterium adolescentis, B. bifidum, and Lactobacillus. In the microbiota of allergic children whose intestinal microbiota was assessed at the onset of allergic symptoms, there was a higher count of Bacteroides; a lower count of Akkermansia muciniphila, Faecalibacterium prausnitzii, and Clostridium; a higher prevalence of B. adolescentis; a lower prevalence of B. catenulatum and Staphylococcus aureus; and a lower bacterial diversity.

Custom AFM for X-ray beamlines: in situ biological investigations under physiological conditions.

A fast atomic force microscope (AFM) has been developed that can be installed as a sample holder for grazing-incidence X-ray experiments at solid/gas or solid/liquid interfaces. It allows a wide range of possible investigations, including soft and biological samples under physiological conditions (hydrated specimens). The structural information obtained using the X-rays is combined with the data gathered with the AFM (morphology and mechanical properties), providing a unique characterization of the specimen and its dynamics in situ during an experiment. In this work, lipid monolayers and bilayers in air or liquid environment have been investigated by means of AFM, both with imaging and force spectroscopy, and X-ray reflectivity. In addition, this combination allows the radiation damage induced by the beam on the sample to be studied, as has been observed on DOPC and DPPC supported lipid bilayers under physiological conditions.

Multiple queens in founding colonies of the neotropical ant Pachycondyla striata Smith (Formicidae: Ponerinae).

In social insects, the typical mode of colony foundation occurs when a single queen is inseminated by a male and establishes a new colony, although we can find interspecific and intraspecific variations in queen number and queen-mating frequencies in a single colony. This study aimed to verify the queen number in Pachycondyla striata (Smith) colonies and to evaluate the level of aggressiveness among workers. We collected 14 colonies of P. striata. The behaviors of individuals from five multiple-queen colonies maintained in laboratory were studied by the method of scan sampling. In order to evaluate aggressiveness, dyadic encounters among heterocolonial and homocolonial workers were performed. The results showed that colonies of P. striata can have two or more mated queens (polygynous colonies) besides to monogynous ones (colony containing one queen). Because in polygynous colonies the number of workers was relatively low, such colonies could represent colonies in the foundation phase that characterize a pleometrosis state. In fact, ovarian development analysis from queens showed that the number of queens in the colonies seemed to be unstable. Despite a few cases of oophagy (egg cannibalism), social hierarchy among queens is unclear in comparison to other Pachycondyla species. In addition, aggressiveness increased with distance among nests. Nearby colonies (less than 1 m apart) showed a low level of aggressiveness, suggesting the presence of polydomy, that is, a unique colony can occupy multiple nests. Polygyny associated to polydomy in founding colonies may confer benefits on growth and dispersion of colonies in the studied environments.

Fed-batch cultivation of Arthrospira (Spirulina) platensis: potassium nitrate and ammonium chloride as simultaneous nitrogen sources.

Arthrospiraplatensis was cultivated in minitanks at 13 klux, using a mixture of KNO(3) and NH(4)Cl as nitrogen source. Fed-batch daily supply of NH(4)Cl at exponentially-increasing feeding rate allowed preventing ammonia toxicity and nitrogen deficiency, providing high maximum cell concentration (X(m)) and high-quality biomass (21.85 mg chlorophyll g cells(-1); 20.5% lipids; 49.8% proteins). A central composite design combined to response surface methodology was utilized to determine the relationships between responses (X(m), cell productivity and nitrogen-to-cell conversion factor) and independent variables (KNO(3) and NH(4)Cl concentrations). Under optimum conditions (15.5mM KNO(3); 14.1mM NH(4)Cl), X(m) was 4327 mg L(-1), a value almost coincident with that obtained with only 25.4mM KNO(3), but more than twice that obtained with 21.5mM NH(4)Cl. A 30%-reduction of culture medium cost can be estimated when compared to KNO(3)-batch runs, thus behaving as a cheap alternative for the commercial production of this cyanobacterium.

X-ray pushing of a mechanical microswing.

We report here for the first time the combination of x-ray synchrotron light and a micro-electro-mechanical system (MEMS). We show how it is possible to modulate in real time a MEMS mass distribution to induce a nanometric and tunable mechanical oscillation. The quantitative experimental demonstration we present here uses periodic thermal dilatation of a Ge microcrystal attached to a Si microlever, induced by controlled absorption of an intensity modulated x-ray microbeam. The mechanism proposed can be envisaged either for the detection of small heat flux or for the actuation of a mechanical system.

Physical analyses of compost from composting plants in Brazil.

Nowadays the composting process has shown itself to be an alternative in the treatment of municipal solid wastes by composting plants. However, although more than 50% of the waste generated by the Brazilian population is composed of matter susceptible to organic composting, this process is, still today, insufficiently developed in Brazil, due to low compost quality and lack of investments in the sector. The objective of this work was to use physical analyses to evaluate the quality of the compost produced at 14 operative composting plants in the Sao Paulo State in Brazil. For this purpose, size distribution and total inert content tests were done. The results were analyzed by grouping the plants according to their productive processes: plants with a rotating drum, plants with shredders or mills, and plants without treatment after the sorting conveyor belt. Compost quality was analyzed considering the limits imposed by the Brazilian Legislation and the European standards for inert contents. The size distribution tests showed the influence of the machinery after the sorting conveyer on the granule sizes as well as the inert content, which contributes to the presence of materials that reduce the quality of the final product.

Outcome of infections caused by multiple drug-resistant bacteria in liver transplant recipients.

OBJECTIVE: To evaluate the impact of infections caused by multiple-drug-resistant (MDR) bacteria on the clinical outcome of liver transplant recipients. METHODS: Retrospective study including all episodes of bacterial infection diagnosed in patients undergoing liver transplantation from January 19, 1999, to June 30, 2002. The diagnosis of bacterial infection required microbiological documentation. Mortality associated with episodes of infection by MDR bacteria was compared to that observed after antibiotic-susceptible bacterial infections. RESULTS: Among 99 patients undergoing liver transplantation during the study period, there were 57 episodes of bacterial infections. Gram-negative bacilli were the predominant etiologic agents (76%) and Pseudomonas aeruginosa was the most frequent bacterial species found in these cases (23 isolates, 28%). Thirty-six episodes of infection (63%) were caused by MDR bacteria. Mean time after transplantation to the diagnosis of infection was 17 days. Mortality associated with episodes of MDR bacterial infections (nine deaths, 25%) was not significantly different from that observed during episodes of antibiotic-susceptible bacteria (five deaths, 24%; P =.92). CONCLUSION: These data suggest that resistance to multiple antimicrobial agents does not have an impact on the mortality associated to bacterial infections in liver transplant recipients.

Comparative study on the mechanism of bradykinin potentiation induced by bradykinin-potentiating peptide 9a, enalaprilat and kinin-potentiating peptide.

The action of a kinin-potentiating peptide (KPP) obtained from tryptic digestion of human serum proteins was compared with that of bradykinin-potentiating peptide 9a (BPP9a; obtained from snake venom) and enalaprilat (a synthetic inhibitor of angiotensin-converting enzyme; ACE) as a means of understanding the mechanism of action of KPP on smooth muscle. KPP potentiated bradykinin-induced contractile effects in guinea-pig ileum and rat uterus, but not the bradykinin-induced relaxation of pre-contracted ileum, whereas BPP9a and enalaprilat potentiated both bradykinin effects. The receptor mediating both the contraction and the relaxation elicited by bradykinin in the ileum was found to be of the B2 type. KPP retained its potentiating effect in the presence of enalaprilat in the guinea-pig ileum and rat uterus, whereas the potentiation evoked by BPP9a was abolished. Enalaprilat inhibited the activity of purified ACE, whereas KPP was completely devoid of such an effect. The potentiating effect of KPP, but not that of BPP9a or enalaprilat, was blocked by compounds that inhibit phospholipase A2 and lipoxygenase activity but not by inhibitors of cyclo-oxygenase or phosphodiesterases. The results suggest that the potentiating effect of KPP (i) does not involve inhibition of ACE; (ii) is not due to an increased affinity of the receptor for bradykinin, and (iii) probably involves post-receptor events linked to phospholipase A2 and to the lipoxygenase pathway.

Potentiation of bradykinin effects and inhibition of kininase activity in isolated smooth muscle.

Prolongation of bradykinin half-life following kininase inhibition has been proposed as the reason for the potentiation of kinin effects. We have reassessed this assumption by using three different isolated smooth muscle preparations and simultaneously studying the inhibition of kininase activity and the potentiation of bradykinin effects by enalaprilat and BPP9a. Rat duodenum displayed higher total kininase activity, metabolizing half of the added bradykinin in 6.5 min, while this time for rat uterus was greater than 60 min. Guinea-pig ileum showed the intermediate value of 14.6 min. Enalaprilat and BPP9a slowed the metabolism of bradykinin by 50-100% in rat duodenum and by 50-180% in guinea-pig ileum, showing that a significant fraction of total kininase activity appears to be due to kininase II. In rat duodenum, an almost complete blockade of kininase activity was achieved when bacitracin and mergetpa were used together with enalaprilat. Enalaprilat and BPP9a potentiated bradykinin effects in guinea-pig ileum and rat uterus. In contrast, bradykinin-induced relaxations and contractions in rat duodenum were not potentiated by enalaprilat, BPP9a, or by the enzyme inhibitor mixture (enalaprilat--bacitracin--mergetpa). The results suggest that inhibition of bradykinin enzymatic metabolism by kininases does not necessarily lead to the potentiation of bradykinin effects.

Estudo comparativo da suscetibilidade de populacoes de Biomphalaria glabrata de Belo Horizonte (MG), a infeccao com Schistosoma mansoni e a moluscicidas. / Comparative study of the susceptibility of Biomphalaria glabrata populations of Belo Horizonte (MG),to infection with Schistosoma mansoni and to molluscacides

O objetivo do estudo foi verificar se haveria diferencas intraespecificas marcantes entre populacoes de Biomphalaria glabrata que habitam criadouros proximos. Foram estudadas 12 populacoes, procedentes do Municipio de Belo Horizonte, Minas Gerais, Brasil. Parte dos descendentes desses moluscos foram infectados com duas cepas de Schistosoma mansoni; "LE", de origem local e "SJ", procedente de Sao Jose dos Campos, Sao Paulo. Outra parte foi usada em ensaios biologicos com os moluscicidas bayluscide (niclosamida) e pentaclorofenol. Os resultados mostraram que existem diferencas na suscetibilidade dos moluscos as duas cepas de S. mansoni. As taxas de infeccao com a cepa "LE" variaram de 27,0 a 94,0% e com "SJ", de 9,0 a 61,0%. Houve diferenca na duracao do periodo de adaptacao dos caramujos as condicoes de laboratorio. Nao houve diferenca estatisticamente significante na suscetibilidade desses moluscos ao bayluscide e pentaclorofenol. Nao houve indicacao de desenvolvimento de resistencia nos moluscos apesar do bayluscide ter sido usado intermitentemente nessa area durante os ultimos 20 anos

Suscetibilidade de Biomphalaria straminea (Dunker, 1848) de Belo Horizonte (MG) a infeccao por cepas de Schistosoma mansoni. / Susceptibility of Biomphalaria straminea (Dunker, 1848) from Belo Horizonte (MG) to infection by strains of Schistosoma mansoni

Caramujos Biomphalaria straminea procedentes da Pampulha, Belo Horizonte, Minas Gerais (Brasil) e seus descendentes criados em laboratorio, foram infectados experimentalmente por tres cepas de Schistosoma mansoni: LE (Belo Horizonte), SJ (Sao Jose dos Campos,SP) ambas mantidas em laboratorio e MGF (Ravena, MG) obtida de fezes humanas. Foram feitos experimentos em laboratorios com as tres cepas de S. mansoni e um experimento no campo com a cepa MGF. A B. straminea de Belo Horizonte mostrou-se suscetivel a todas as cepas do trematodeo nas condicoes experimentais. As taxas de infeccao foram de 19,0% (LE), 8,3% (SJ), 5,7% (MGF) em condicoes de laboratorio e 1,3% (MGF), no campo. Em 640 caramujos B.straminea coletados no campo, nao foi evidenciada a presenca de esporocistos ou cercarias de S. mansoni. Esses resultados sugerem que a B. straminea de Belo Horizonte, apesar de nao ter sido encontrada naturalmente infectada ate o momento, podera tornar-se hospedeira do S. mansoni nessa regiao

Suscetibilidade de populacoes de Biomphalaria Straminea (Dunker, 1848) de Minas Gerais, a infeccao por Schistosoma mansoni. / Susceptibility of populations of Biomphalaria straminea (Dunker, 1848) from Minas Gerais, to infection due to Schistosoma mansoni

Caramujos Biomphalaria straminea descendentes de exemplares coletados em cinco municipios do Estado de Minas Gerais, foram infectados experimentalmente com duas cepas de Schistosoma mansoni: LE, procedente de Belo Horizonte (MG) e SJ, procedente de Sao Jose dos Campos (SP). As taxas de infeccao com a cepa LE variaram de 0,0 a 5,0% e com a cepa SJ de 2,0% a 11,0%. A mortalidade maxima observada nos experimentos foi de 56,0% e nos controles foi de 50,0%. Os indices de infeccao experimental foram semelhantes aos registrados por outros autores. Os resultados obtidos demonstraram que essas populacoes de B. straminea de Minas Gerais nao sao refratarias a infeccao pelo S. mansoni

Estudo comparativo de duas tecnicas para obtencao de miracidios de Schistosoma mansoni em fezes humanas. / Comparative study of 2 technics for obtention of miracidia of Schistosoma mansoni from human feces

Foi comparada a eficacia de duas tecnicas para obtencao de miracidios de Schistosoma mansoni de ovos provenientes de fezes humanas para infeccao de Biomphalaria glabrata. Na tecnica "A" utilizou-se agua desclorada a 4 graus C e na "B", solucao salina (0,85%) e agua destilada em temperatura ambiente para suspender as fezes. Foram utilizadas 8 cepas humanas de S. mansoni, procedentes de cinco localidades do Estado de Minas Gerais, antes do tratamento. O numero de ovos de S. mansoni por grama de fezes variou de 360 a 2.328. As taxas de eclosao dos ovos e de infeccao dos moluscos foram de 3,3% e 37,0% respectivamente, com a tecnica "A" e de 6,9% e 27,0% respectivamente, com a tecnica "B". Nao houve diferenca significativa entre a mortalidade dos moluscos nas duas tecnicas. A analise dos resultados mostrou que a tecnica "B" apresentou maior porcentagem de eclosao dos ovos de S. mansoni mas a tecnica "A" apresentou melhor taxa de infeccao dos moluscos