Membrane Functions and Tolerance to Aromatic Hydrocarbon Fungitoxicants in Conidia of Fusarium solani

With the use of ³²P-labeled phosphate and ⁴²K₂CO₃ the effect of diphenyl on permeability and uptake properties of the cytoplasmic membrane in wild type and diphenyl-tolerant mutant conidia of Fusarium solani f. cucurbitae was studied. No general damage to the membrane with unspecific leakage of cell constituents was demonstrated under conditions in which diphenyl prevents germination of wild type conidia. The fresh conidia do not require exogenous supply of energy for the uptake of phosphate or of potassium. In the wild type the entry of ³²P is inhibited but that of ⁴²K strikingly stimulated by diphenyl. Independently of the tolerant mutant gene present, the mutant conidia are significantly less sensitive to the phosphate uptake inhibition and not affected at all by diphenyl with respect to the uptake of potassium. The latter difference from the wild type seems to indicate genetic control of some property of the potassium transport system in this fungus.     

Visitation rate of pollinators and nectar robbers to the flowers and inflorescences of Tabebuia aurea (Bignoniaceae): effects of floral display size and habitat fragmentation

Large floral displays favour pollinator attraction and the import and export of pollen. However, large floral displays also have negative effects, such as increased geitonogamy, pollen discounting and nectar/pollen robber attraction. The size of the floral display can be measured at different scales (e.g. the flower, inflorescence or entire plant) and variations in one of these scales may affect the behaviour of flower visitors in different ways. Moreover, the fragmentation of natural forests may affect flower visitation rates and flower visitor behaviour. In the present study, video recordings of the inflorescences of a tree species (Tabebuia aurea) from the tropical savannah of central Brazil were used to examine the effect of floral display size at the inflorescence and tree scales on the visitation rate of pollinators and nectar robbers to the inflorescence, the number of flowers approached per visit, the number of visits per flower of potential pollinators and nectar robbers, and the interaction of these variables with the degree of landscape disturbance. Nectar production was quantified with respect to flower age. Although large bees are responsible for most of the pollination, a great diversity of flower insects visit the inflorescences of T. aurea. Other bee and hummingbird species are highly active nectar robbers. Increases in inflorescence size increase the visitation rate of pollinators to inflorescences, whereas increases in the number of inflorescences on the tree decrease visitation rates to inflorescences and flowers. This effect has been strongly correlated with urban environments in which trees with the largest floral displays are observed. Pollinating bees (and nectar robbers) visit few flowers per inflorescence and concentrate visits to a fraction of available flowers, generating an overdispersed distribution of the number of visits per inflorescence and per flower. This behaviour reflects preferential visits to young flowers (including flower buds) with a greater nectar supply.     

Sustained Reduction of the Dengue Vector Population Resulting from an Integrated Control Strategy Applied in Two Brazilian Cities

Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology. The SMCP-Aedes, a system based on open technology and open data standards, was set up from March/2008 to October/2011 as a pilot trial in two sites of Pernambuco -Brazil: Ipojuca (10,000 residents) and Santa Cruz (83,000), in a joint effort of health authorities and staff, and a network of scientists providing scientific support. A widespread infestation by Aedes was found in both sites in 2008–2009, with 96.8%–100% trap positivity. Egg densities were markedly higher in SCC than in Ipojuca. A 90% decrease in egg density was recorded in SCC after two years of sustained control pressure imposed by suppression of >7,500,000 eggs and >3,200 adults, plus larval control by adding fishes to cisterns. In Ipojuca, 1.1 million mosquito eggs were suppressed and a 77% reduction in egg density was achieved. This study aimed at assessing the applicability of a system using GIS and spatial statistic analysis tools for quantitative assessment of mosquito populations. It also provided useful information on the requirements for reducing well-established mosquito populations. Results from two cities led us to conclude that the success in markedly reducing an Aedes population required the appropriate choice of control measures for sustained mass elimination guided by a user-friendly mosquito surveillance system. The system was able to support interventional decisions and to assess the program’s success. Additionally, it created a stimulating environment for health staff and residents, which had a positive impact on their commitment to the dengue control program.     

Effect of Differentiation on the Leucine Enkephalin-Degrading Soluble Enzymes Released by the K562(S) Cell Line

Leu-enkephalin hydrolysis kinetics were measured in the presence of soluble supernatants obtained from cultures of the K562(S) leukaemic cell line. Under these conditions, the substrate is degraded with formation of two distinct patterns of the hydrolysis by-products: in one pattern, similar amounts of Tyr and Tyr-Gly are formed; in the other, only Tyr-Gly can be measured. Kinetic data suggest that soluble proteolyses are released by these cells, and that either dipeptidylaminopeptidases alone, or both aminopeptidases and dipeptidylaminopeptidases are involved in substrate hydrolysis. This alternation of hydrolysis patterns appears consistent with existing data on the heterogeneity of K562 cells. In contrast with these results, chromatographic separation of the soluble enzymes indicates the release of all three classes of proteolyses known to hydrolyze enkephalins: aminopeptidases, dipeptidylaminopeptidases and dipeptidylcarboxypeptidases. In cells induced to differentiate by treatment with butyric acid, substrate hydrolysis is increased, and the pattern of the enzymes released is modified. In these cells, variations in both total proteolytic activity, and ratio between the three enzyme classes mentioned above are only minor, while the ratio between the different enzyme species within each class is greatly modified. Data obtained suggest that the expression of soluble enzymes is modified by differentiation. These data may also be interpreted as stressing the role of competition in controlling substrate hydrolysis by the multiple enzymes co-released by K562(S) cells.     

Dammarane triterpenes from Cabralea canjerana (Vell.) Mart. (Meliaceae): Their chemosystematic significance

The stem of Cabralea canjerana (Vell.) Mart. yielded three new dammarane triterpenes 20S,24S-epoxy-7β,25-dihydroxy-3,4-secodammar-4(28)-en-3-oic acid, 20S,24S-epoxy-7β,15α,25-trihydroxy-3,4-secodammar-4(28)-en-3-oic acid and 20S,24R-epoxy-7β,22ξ,25-trihydroxy-3,4-secodammar-4(28)-en-3-oic acid, which were identified on the basis of spectroscopic methods. The known dammarane triterpenes ocotillone, eichlerianic acid, shoreic acid and the sterols sitosterol, campesterol, stigmasterol, sitostenone and stigmast-5-en-3-one were also isolated and identified. The branches yielded the above three known dammaranes and eichlerialactone. The dammaranes in C. canjerana display strong similarities with Trichilieae tribe, which contains several dammaranes. The data reported herein thus provide firm support for placing Cabralea within the subfamily Melioideae, Trichilieae tribe.     

Clinical relevance of lipid panel and aminotransferases in the context of hepatic steatosis and fibrosis as measured by transient elastography (FibroScan®)

BackgroundNonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease and is associated with various co-morbidities. Transient elastography (FibroScan®) is a non-invasive method to detect NAFLD using the controlled attenuation parameter (CAP). We aimed to evaluate the association of the lipid panel and aminotransferases concentrations with the presence or absence of steatosis and fibrosis.MethodsOne hundred and five patients with NAFLD were included. Hepatic steatosis was quantified by CAP (dB/m) and liver stiffness by Kilopascals (kPa), these values were then analyzed against patient lipid panel and serum concentrations of the liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT). A correlation and multiple regression were used. Mann-Whitney U test was used as non-parametric analysis.ResultsWe observed an association between hepatic steatosis and total cholesterol (B = 0.021, p = 0.038, Exp (B) = 1.021, I.C = 1.001-1.041) as well as serum triglycerides (B = 0.017, p = 0.006, Exp (B) = 1.018 and I.C = 1.005-1.030). Similarly, we found an association between significant hepatic fibrosis and lower concentrations of total cholesterol (B = -0.019, p = 0.005, Exp (B) = 0.982 I.C = 0.969-0.995) and elevated AST (B = 0.042, p = 3.25 × 10^-4, Exp (B) = 1.043 I.C = 1.019-1.068) independent of age, gender and BMI.ConclusionsOur results suggest that, total cholesterol and triglyceride concentrations positively correlate with hepatic steatosis while significant hepatic fibrosis is associated with lower total cholesterol and higher AST concentrations.