Ilex paraguariensis extracts extend the lifespan of Drosophila melanogaster fed a high-fat diet

Studies have suggested that total energy intake and diet composition affect lifespan and ageing. A high-fat diet induces oxidative stress and affects the development of diseases. In contrast, antioxidants are capable of reducing its harmful effects. Yerba mate beverages are an important source of antioxidants, but there is scarce knowledge about their effects on suppressing fat accumulation. Here, we investigated the compounds present in yerba mate extracts and assessed their effects on Drosophila melanogaster given a high cholesterol diet. LS-ESI-MS analysis showed the presence of matesaponins, phenolic compounds and methylxanthines in all of the examined extracts. In Drosophila, under extract treatment conditions, the mean lifespan was significantly extended from 38 to 43 days, there was an increase in the ability to support induced stress and decrease in lipid peroxidation products. Moreover, yerba mate extracts recovered the glutathione S-transferases (GST) activity and reduced the cholesterol level. Taken together, our results support that extracts can extend lifespan by reducing the detrimental effect of a high-fat diet in D. melanogaster, and this outcome can be associated with the compound content in the extracts. This study improves the understanding of natural interventions that reduce stress-induced oxidative damage, which is fundamental in promoting healthy ageing.

Alteration of the reproductive patterns in drosophila melanogaster by effects of high concentrations of boron on in vitro cultured medium / Alteración de los patrones reproductivos en drosophila melanogaster por efectos de altas concentraciones de boro en un medio de cultivo in vitro

The objective of this study was to evaluate the effects of boron (B) using as a biological model Drosophila malanogaster. Analizing specifically the responses over descendency to doses of 6,0 and 12 mg/L, comparing a control group which culture medium was prepared with water with boron concentrations of 0,6 mg/L, according to World Health Organization. The results show a significative alteration in the number of descendency from F1 to F3 and then a tendency to normalization in F4 and F5. Also a significant change in proportions between the males and females, with an acute effect on F1 and then a possible chronic effect from F2 to F5, increasing the proportion of females over males. This differences between genders are significant only until F4, on F5 these proportions are not significant. In F3 in doses of 12.0 mg/L of boron, it is observed a larger range of changes, altering the phenotypic expression, where the numbers of males which increase their size are significantly higher of those females who increase their size, 10 percent and 5,2 percent respectively. There is a tendency to normality in every pattern of study from the descendants of F4 and F5, above all the percentage of survival, possibly due action of steroid hormones of resistance to stress such as "ecdysone hormone".

El objetivo de este estudio fue evaluar el efecto del boro (B), usando como modelo biológico a Drosophila melanogaster. Específicamente analizar las respuestas sobre la descendencia a dosis de 6,0 y 12 mg/L y comparar con el grupo control cuya concentración de boro en el agua del medio de cultivo no supera los 0,6 mg/L, según los estándares de la Organización Mundial de la Salud. Los resultados muestran una alteración significativa en el número de la descendencia desde F1 a F3 y luego una tendencia a la normalización a partir de la F4 y F5. También hay un cambio significativo en las proporciones entre machos y hembras, con un efecto agudo en F1 y luego un posible efecto crónico desde F2 a F5, aumentando la proporción de hembras con respecto a los machos. Sin embargo estas diferencias entre sexos ya no son significativas solamente hasta F4. En F5 estas proporciones no son significativas. En F3 en dosis de 12 mg/L de boro, se observan los mayores cambios, alterando la expresión fenotípica, donde el número de machos que incrementan su tamaño, son significativamente más altos con respecto a las hembras que aumentan de tamaño. La tendencia a la normalidad en todos los patrones de estudio a partir de la descendencia F4 a F5, sobre todo en el porcentaje de sobreviva, posiblemente se deba a la acción de hormonas esteroidales de resistencia al estrés, tal como la hormona "Ecdysona".

Drosophila-based in vivo assay for the validation of inhibitors of the epidermal growth factor receptor/Ras pathway.

Overexpression of epidermal growth factor receptor (EGFR) is a common phenomenon observed in most cancers. Clinical treatment of such cancer involves the use of chemotherapeutic agents such as ge ? tinib and erlotinib which are inhibitors of tyrosine kinase (TK). These small molecules bind to the ATP-binding sites of the TK domain of EGFR.Our in silico analysis suggests that the TK domains of Drosophila and human EGFR are highly conserved. We therefore employed the Drosophila system to validate the in silico observations made with two important anticancer drugs.Since a large number of mutant flies are available,it was possible to investigate the various components of the EGFR/Ras/Raf/MAPK pathways and the phosphorylation status of diphosphorylated extracellular signal-regulated kinase (dp-ERK1/2). These studies confirm the binding of the anilinoquinazolines to the Drosophila EGFR protein and modulation of its activity. Thus,Drosophila appears to be a robust and simple model system for screening newer anticancer drugs that act as TK inhibitors (TKIs).

Circadian clocks and life-history related traits: is pupation height affected by circadian organization in Drosophila melanogaster?

In D. melanogaster, the observation of greater pupation height under constant darkness than under constant light has been explained by the hypothesis that light has an inhibitory effect on larval wandering behaviour, preventing larvae from crawling higher up the walls of culture vials prior to pupation. If this is the only role of light in affecting pupation height, then various light : dark regimes would be predicted to yield pupation heights intermediate between those seen in constant light and constant darkness. We tested this hypothesis by measuring pupation height under various light : dark regimes in four laboratory populations of Drosophila melanogaster. Pupation height was the greatest in constant darkness, intermediate in constant light, and the least in a light/dark regime of LD 14:14 h. The results clearly suggest that there is more to light regime effects on pupation height than mere behavioural inhibition of wandering larvae, and that circadian organization may play some role in determining pupation height, although the details of this role are not yet clear. We briefly discuss these results in the context of the possible involvement of circadian clocks in life-history evolution.

GAL4 causes developmental defects and apoptosis when expressed in the developing eye of Drosophila melanogaster

The UAS/GAL4 ectopic expression system is widely used in Drosophila melanogaster for the overexpression of transgenes. This system operates under the assumption that the yeast transcription factor, GAL4, is inactive in D. melanogaster. Thus, GAL4 can be expressed under the control of D. melanogaster -specific promoters with little effect upon the organism. We have shown that expression of GAL4 in the developing eye under the control of the glass multiple reporter (GMR) promoter element does have an effect on eye development. Although GMR-GAL4 heterozygotes appear normal when raised at 25 degrees C, the homozygotes have a highly disorganized ommatidial array. In addition, the levels of apoptosis in the third-instar larval eye imaginal disc (where GAL4 is expressed) are slightly higher in GMR-GAL4 heterozygotes, and much higher in GMR-GAL4 homozygotes when compared to wild type discs. The morphological eye defects caused by GMR-GAL4 are significantly enhanced when flies are raised at 29 degrees C (presumably due to the higher activity of GAL4 at this temperature); however, the levels of apoptosis appear to be similar at these two temperatures. Taken together, these data suggest that GAL4 can have adverse effects on D. melanogaster development, especially at high expression levels. In addition, GAL4 appears to induce apoptosis even in the absence of any visible morphological defects. Thus, despite the benefits of the UAS/GAL4 ectopic expression system, one must use caution in the design and interpretation of experiments

When neurobiology and genetics meet: the study of visual system development in Drosophila melanogaster

O sistema visual de Drosophila melanogaster constitui um modelo excepcionalmente adequado ao estudo dos mecanismos de sinalizaçäo inter- e celulares. O presente trabalho descreve alguns dos avanços recentes nesta área, os quais näo apenas ilustram o potencial combinado das abordagens genética e neurobiológica, mas também sugerem uma notável conservaçäo evolutiva dos mecanismos moleculares especificadores do desenvolvimento ontogenético em metazoários.

Localization and mapping of the main gene responsible for fast development in Drosophila melanogaster

Um estoque de Drosophila melanogaster Oregon-R foi submetido à seleçäo em massa durante 682 e 459 geraçöes para velocidade de desenvolvimento rápido e lento, respectivamente. O presente trabalho descreve os experimentos que localizaram o gene principal para velocidade de desenvolvimento rápido no 3§ cromossoma usando marcadores de corpo e enzimático. O mapeamento por recombinaçäo usando as médias de eclosäo colocaram o gene para desenvolvimento rápido a 3.46.55.

Functional organization of tau proteins during neuronal differentiation and development

Tau proteins play major regulatory roles in the organization and integrity of the cystoskeletal networks. In neurons, a specific axonal compartmentalization of tau has been shown. However, recent studies demonstrate that tau displays a widespread distribution in a variety of non-neuronal cell types. These proteins have been found in human fibroblasts and in several transformed cell lines. The heterogenous family of tau is formed by a set of molecular species that share common peptide sequences. There is a single gene that contains several exons enconding for the six different tau isoforms in mammalian brain. Alternative splicing of a common RNA transcript as well as post-translational modifications contribute to its heterogeneity. Tau isoforms generated by splicing differ from one another by having either three or four repeats in their C-terminal half, and a variable number of inserts in their N-terminal moiety. These repeats have been shown to constitute microtubule-binding motifs. In this review some relevant aspects of tau function and its regulation are analysed. Three major topics are discussed. The first one focuses on the tau roles in regulating the interactions between microtubules with actin filaments and with intermediate filment systems. Another problem deals with the question of whether tau isoforms segregate into functionally different subsets of microtubules in axonal processes, or tau associates with these polymers in a random fashion. The third question that emerges is the involvement of tau and tau-like proteins in morphogenetic events. The regulation of the interactions of DMAP-85, a recently discovered tau-like protein, with the cytoskeleton during development of Drosophila melanogaster is analyzed.

Efeitos do herbicida Roundup sobre a viabilidade ovo-adulto de Drosophila melanogaster / Effects of the Roundup herbicide on the egg-adult viability of the Drosophila melanogaster

No presente trabalho, foram estudados os efeitos do herbicida "Roundup" sobre a viabilidade ovo-adulto de quatro linhagens de Drosophila melanogaster: selvagem, "yellow", taxi e vestigial. A viabilidade foi medida através da contagem do número de indivíduos adultos nascidos a partir de um número conhecido de ovos, coletados em três tipos diferentes de concentraçäo de herbicida. Os resultados mostraram que houve uma reduçäo significante da viabilidade ovo-adulto, diretamente proporcional a concentraçäo do herbicida, isto é, quanto maior a concentraçäo, maior a reduçäo da viabilidade. Verificou-se, ainda, que as linhagens "yellow" e selvagem foram as mais resistentes aos efeitos do herbicida, enquanto que a linhagem vestigial foi a mais sensível