The interaction of Trichomonas vaginalis and Tritrichomonas foetus with epithelial cells in vitro

The Madin-Darby canine kidney epithelial cell line (MDCK) was used as a model for trichomonad-host cell interaction. Two laboratory strains of the human parasite Trichomonas vaginalis and the cattle's parasite Tritrichomonas foetus or their supernatants from axenic cultures were allowed to interact with confluent epithelial cultures. The interaction process studied by transmission and scanning electron microscopy revealed that both parasites adhere to monolayers through flagella, cell body and particularly for T. foetus, through the posterior projection of the axostyle. A close contact region between the trichomonad's surface and MDCK cells was observed. A study of the involvement of trichomonad surface component in the interaction process indicated that cytochalasin B treated-parasites adhere much less to epithelial monolayers than untreated parasites. Colchicine treatment did not affect such adhesion. Treatment of the parasites with trypsin reduced the adhesion of trichomonads to monolayers but did not interfere with the cytopathic effect. In contrast, treatment of the parasites with neuraminidase did not interfere with their adhesion to epithelial cells and the monolayer destruction was further increased.     

A VANADIUM BROMOPEROXIDASE CATALYZES THE FORMATION OF HIGH‐MOLECULAR‐WEIGHT COMPLEXES BETWEEN BROWN ALGAL PHENOLIC SUBSTANCES AND ALGINATES1

The interaction between phenolic substances (PS) and alginates (ALG) has been suggested to play a role in the structure of the cell walls of brown seaweeds. However, no clear evidence for this interaction was reported. Vanadium bromoperoxidase (VBPO) has been proposed as a possible catalyst for the binding of PS to ALG. In this work, we studied the interaction between PS and ALG from brown algae using size exclusion chromatography (SEC) and optical tweezers microscopy. The analysis by SEC revealed that ALG forms a high‐molecular‐weight complex with PS. To study the formation of this molecular complex, we investigated the in vitro interaction of purified ALG from Fucus vesiculosus L. with purified PS from Padina gymnospora (Kütz.) Sond., in the presence or absence of VBPO. The interaction between PS and ALG only occurred when VBPO was added, indicating that the enzyme is essential for the binding process. The interaction of these molecules led to a reduction in ALG viscosity. We propose that VBPO promotes the binding of PS molecules to the ALG uronic acids residues, and we also suggest that PS are components of the brown algal cell walls.     

Differential effects of temperature change and human impact on European Late Quaternary mammalian extinctions

Species that inhabited Europe during the Late Quaternary were impacted by temperature changes and early humans, resulting in the disappearance of half of the European large mammals. However, quantifying the relative importance that each factor had in the extinction risk of species has been challenging, mostly due to the spatio‐temporal biases of fossil records, which complicate the calibration of realistic and accurate ecological niche modeling. Here, we overcome this problem by using ecotypes, and not real species, to run our models. We created 40 ecotypes with different temperature requirements (mean temperature from ?20 °C to 25 °C and temperature range from 10 °C to 40 °C) and used them to quantify the effect of climate change and human impact. Our results show that cold‐adapted ecotypes would have been highly affected by past temperature changes in Europe, whereas temperate and warm‐adapted ecotypes would have been positively affected by temperature change. Human impact affected all ecotypes negatively, and temperate ecotypes suffered the greatest impacts. Based on these results, the extinction of cold‐adapted species like Mammuthus primigenius may be related to temperature change, while the extinction of temperate species, like Crocuta crocuta, may be related to human impact. Our results suggest that temperature change and human impact affected different ecotypes in distinct ways, and that the interaction of both impacts may have shaped species extinctions in Europe.     

Proliferative activity in clinically healthy oral mucosa exposed to tobacco smoking and alcohol: a longitudinal study using the agNOR staining technique

OBJECTIVE: To evaluate cell proliferation in clinically healthy oral mucosa exposed to smoking and alcohol carcinogens over a period of 24 months using the AgNOR staining technique. STUDY DESIGN: Sixty patients were initially evaluated: 17 were control individuals, 25 were smokers and 18 were smokers and alcohol drinkers. Fifty-two of these patients were reevaluated. Specimens for cytology were obtained from swabs of lower lip mucosa, border of the tongue and floor of the mouth and underwent AgNOR staining for evaluation of mean number and mean area of AgNOR dots per nucleus and percentage of nuclei with > 3 and > 5 AgNOR dots. Student t and Kruskal-Wallis tests were used to compare values obtained. RESULTS: A statistically significant increase was found in mean number of AgNOR dots per nucleus in 2 groups. One group showed a tendency toward increase of these values. The results of the longitudinal evaluation (Kruskal-Wallis test) revealed a statistically significant difference in number and area of AgNOR dots in the cells of the lower lip. CONCLUSION: The increase of the variables suggests that the longitudinal evaluation of changes in cell proliferation in individuals exposed to smoking and alcohol carcinogens may be a useful monitoring tool.     

Synthetic Aurones: New Features for Schistosoma mansoni Therapy

In this work, two synthetic aurones revealed moderate schistosomicidal potential in in vitro and in vivo assays. Aurones ( 1 ) and ( 2 ) promoted changes in tegument integrity and motor activity, leading to death of adult Schistosoma mansoni worms in in vitro assays. When administered orally (two doses of 50 mg/kg) in experimentally infected animals, synthetic aurones ( 1 ) and ( 2 ) promoted reductions of 56.20 % and 57.61 % of the parasite load and stimulated the displacement towards the liver of the remaining adult worms. The oogram analysis revealed that the treatment with both aurones interferes with the egg development kinetics in the intestinal tissue. Seeking an action target for compounds ( 1 ) and ( 2 ), the connection with NTPDases enzymes, recognized as important therapeutic targets for S. mansoni, was evaluated. Molecular docking studies have shown promising results. The dataset reveals the anthelmintic character of these compounds, which can be used in the development of new therapies for schistosomiasis.     

A new species of Bricelochlorops Paganelli and the first record of Urubambina rufa (Duda) (Diptera: Chloropidae) from Brazil

The subfamily Chloropinae comprises about 442 described species, with only one species recorded from the Brazilian Amazon. The genus Bricelochlorops Paganelli was represented by a unique species from Rio de Janeiro, Brazil. The species Urubambina rufa (Duda) is the only species of the genus Urubambina Paganelli and has been recorded only from Peru. A new species of Bricelochlorops, B. celutae sp. nov., is described here and Urubambina rufa is recorded for the first time in Brazil. Both species were collected in the state of Acre. A key to species of Bricelochlorops is provided.     

Ageing, genetics and the somatotropic axis

Research on ageing made a big leap forward when genes regulating lifespan were discovered about a decade ago. First isolated by screening the genome of the nematode Caenorhabditis elegans, most of these genes belong to an essential signalling pathway that is highly conserved during animal evolution. Orthologous genes in vertebrate species are the families of genes coding for insulin, insulin-like growth factors (IGF) and related proteins. Intensively studied and well-known for their pivotal roles in proliferation, differentiation, survival and metabolism of most cells, we now discover their multiples functions with respect to the control of longevity and their ability to modulate the cell's responses to oxidative stress, a major cause of cellular and organismal ageing. The activity of IGF signalling in mammals depends on a complex interplay of endocrine signals that together constitute the somatotropic axis. Accordingly, several components of this hormone axis, like growth hormone or growth hormone releasing hormone receptors, regulate efficiently animal longevity, which has been elegantly demonstrated by studies performed in genetically modified mouse models. From this and other work, it becomes increasingly clear that the control of ageing is a question of hormonal regulations. We here present several of these models and discuss the respective contributions of insulin and IGF signalling to the regulation of lifespan. We review data on the Klotho gene that acts on lifespan via surprising and not yet fully understood molecular mechanisms, connecting this new, hormone-like substance to IGF and insulin signalling. We further report recent evidence showing that human lifespan might be controlled in similar ways. Finally, we shed some light on clinical GH treatment in humans, from an endocrinologist's point of view.     

Simulation of integrated first and second generation bioethanol production from sugarcane: comparison between different biomass pretreatment methods

Sugarcane bagasse is used as a fuel in conventional bioethanol production, providing heat and power for the plant; therefore, the amount of surplus bagasse available for use as raw material for second generation bioethanol production is related to the energy consumption of the bioethanol production process. Pentoses and lignin, byproducts of the second generation bioethanol production process, may be used as fuels, increasing the amount of surplus bagasse. In this work, simulations of the integrated bioethanol production process from sugarcane, surplus bagasse and trash were carried out. Selected pre-treatment methods followed, or not, by a delignification step were evaluated. The amount of lignocellulosic materials available for hydrolysis in each configuration was calculated assuming that 50% of sugarcane trash is recovered from the field. An economic risk analysis was carried out; the best results for the integrated first and second generation ethanol production process were obtained for steam explosion pretreatment, high solids loading for hydrolysis and 24–48 h hydrolysis. The second generation ethanol production process must be improved (e.g., decreasing required investment, improving yields and developing pentose fermentation to ethanol) in order for the integrated process to be more economically competitive.     

Acetylenic 2-phenylethylamides and new isobutylamides from Acmella oleracea (L.) R. K. Jansen,a Brazilian spice with larvicidal activity on Aedes aegypti

Ethanol extract obtained from dried leaves of Acmella oleracea afforded after a liquid/liquid partition procedure a larvicidal hexane fraction (LC₅₀ = 145.6 ppm) and a non larvicidal dichloromethane one. From the inactive fraction, three amides were identified, two new structures, named deca-6,9-dihydroxy-(2E,7E)-dienoic acid isobutylamide (1), deca-8,9-dihydroxy-(2E,6Z)-dienoic acid isobutylamide (2) and the known nona-2,3-dihydroxy-6,8-diynoic acid 2-phenylethylamide (3). Bioassay-guided chromatographic fractionation of the hexane partition led to the identification of an amide mixture, nona-(2Z)-en-6,8-diynoic acid 2-phenylethylamide (4) and deca-(2Z)-en-6,8-diynoic acid 2-phenylethlylamide (5). This mixture was active against Aedes aegypti larvae at LC₅₀ = 7.6 ppm. Low toxicity of crude extracts and derived fractions on Artemia salina nauplies showed the possibility of using them to control the A. aegypti mosquito larvae. This is the first report on larvicidal activity of acetylenic 2-phenylethylamides and their identification in A. oleracea leaves.