Distribution and taxonomy of Pyrgophorus platyrachis (Caenogastropoda: Hydrobiidae) in the Sistema de Maracaibo, Venezuela

The presence of a microgastropod identified as Potamopyrgus sp. was detected previously in the Maracaibo System; nevertheless, a detailed morphological analysis identified this snail in other genera. The objective of this work is to update the distribution and taxonomy of Pyrgophorus platyrachis in the Maracaibo System, Venezuela in samples obtained between 2001 and 2009. The presence of hundreds of individuals of P. platyrachis were observed in the estuary, indeed in the localities of the Gran Eneal lagoon (4 111 snails), Peonías lagoon (229 snails), Punta Capitán Chico (758 snails), San Francisco (2 517 snails), Curarire (240 snails), Apon River mouth (173 snails), Ojeda City (240 snails), Bachaquero (128 snails) and Tomoporo de Agua (385 snails). We performed a taxonomical analysis, and emphasized in ecological aspects, such as the distribution of the species and habitat features, as near vegetation and type of associated sediment. We found three morphotypes of the species, one smooth, another with spiral striations and the other with spines. Smooth morphotype was exclusive of the Gran Eneal lagoon, Peonías lagoon, Punta Capitan Chico and Apon River mouth localities, whereas the other two morphotypes were found together in the remaining localities. According to our detailed anatomical and taxonomical analysis we propose a synonymy between P. platyrachis and the other species described like Pyrgophorus parvulus and Pyrgophorus spinosus.     

Resting metabolic rates of two orbweb spiders: a first approach to evolutionary success of ecribellate spiders

Spiders are considered conservative with regard to their resting metabolic rate, presenting the same allometric relation with body mass as the majority of land-arthropods. Nevertheless, web-building is thought to have a great impact on the energetic metabolism, and any modification that affects this complex behavior is expected to have an impact over the daily energetic budget. We analyzed the possibility of the presence of the cribellum having an effect on the allometric relation between resting metabolic rate and body mass for an ecribellate species (Zosis geniculata) and a cribellate one (Metazygia rogenhoferi), and employed a model selection approach to test if these species had the same allometric relationship as other land-arthropods. Our results show that M. rogenhoferi has a higher resting metabolic rate, while Z. geniculata fitted the allometric prediction for land arthropods. This indicates that the absence of the cribellum is associated with a higher resting metabolic rate, thus explaining the higher promptness to activity found for the ecribellate species. If our result proves to be a general rule among spiders, the radiation of Araneoidea could be connected to a more energy-consuming life style. Thus, we briefly outline an alternative model of diversification of Araneoidea that accounts for this possibility.     

Glucose-Induced Regulation of NHEs Activity and SGLTs Expression Involves the PKA Signaling Pathway

The effect of glucose on the intracellular pH (pH_i) recovery rate (dpH_i/dt) and Na⁺-glucose transporter (SGLT) localization was investigated in HEK-293 cells, a cell line that expresses endogenous NHE1, NHE3, SGLT1, and SGLT2 proteins. The activity of the Na⁺/H⁺ exchangers (NHEs) was evaluated by using fluorescence microscopy. The total and membrane protein expression levels were analyzed by immunoblotting. In cells cultivated in 5 mM glucose, the pH_i recovery rate was 0.169 ± 0.020 (n = 6). This value did not change in response to the acute presence of glucose at 2 or 10 mM, but decreased with 25 mM glucose, an effect that was not observed with 25 mM mannitol. Conversely, the chronic effect of high glucose (25 mM) increased the pH_i recovery rate (~40%, P < 0.05), without changes in the total levels of NHE1, NHE3, or SGLT1 expression, but increasing the total cellular (~50%, P < 0.05) and the plasma membrane (~100%, P < 0.01) content of SGLT2. Treatment with H-89 (10⁻⁶ M) prevented the stimulatory effect of chronic glucose treatment on the pH_i recovery rate and SGLT2 expression in the plasma membrane. Our results indicate that the effect of chronic treatment with a high glucose concentration is associated with increased NHEs activity and plasma membrane expression of SGLT2 in a protein kinase A-dependent way. The present results reveal mechanisms of glucotoxicity and may contribute to understanding the diabetes-induced damage of this renal epithelial cell.     

Glial reactivity in dogs with visceral leishmaniasis: correlation with T lymphocyte infiltration and with cerebrospinal fluid anti-<Emphasis Type="Italic">Leishmania</Emphasis> antibody titres

Visceral leishmaniasis is a multisystemic zoonotic disease that can manifest with several symptoms, including neurological disorders. Because glial cells are extensively associated with the immune response within the brain, we evaluated the morphology of astrocytes and microglia of dogs naturally infected with Leishmania chagasi. We used immunohistochemical and lectin-histochemical techniques for morphological analyses and we also examined the glial correlation with lymphocyte infiltration of the brain and with the presence of anti-Leishmania antibodies within the cerebrospinal fluid of the dogs. Although we did not detect a shared morphological pattern in the astrocytes or microglia in the brain tissue, these cells were more intensely labelled in infected dogs than in the control group. The density of microglia was increased in the ependymal/subependymal area, thus demonstrating a strong correlation with the presence of T lymphocytes and with cerebrospinal fluid antibody titres. Thus, our results indicate a pro-inflammatory state in the brains of dogs naturally infected with L. chagasi and strongly suggest that microglia and astrocytes are involved in the pathogenesis of the neurological disorders of visceral leishmaniasis in dogs.     

Wavelet analysis of human DNA

This paper studies the human DNA in the perspective of signal processing. Six wavelets are tested for analyzing the information content of the human DNA. By adopting real Shannon wavelet several fundamental properties of the code are revealed. A quantitative comparison of the chromosomes and visualization through multidimensional and dendograms is developed.     

Participation of the liver gluconeogenesis in the glibenclamide-induced hypoglycaemia in rats

We previously demonstrated an increased liver gluconeogenesis (LG) during insulin‐induced hypoglycaemia. Thus, an expected effect of sulphonylureas induced hypoglycaemia (SIH) could be the activation of LG. However, sulphonylureas infused directly in to the liver inhibits LG. Considering these opposite effects we investigated herein LG in rats submitted to SIH. For this purpose, 24 h fasted rats that received glibenclamide (10 mg kg^?1) were used (SIH group). Control group received oral saline. Glycaemia at 30, 60, 90, 120 and 150 min after oral administration of glibenclamide were evaluated. Since the lowest glycaemia was obtained 120 min after glibenclamide administration, this time was chosen to investigate LG in situ perfused livers. The gluconeogenesis from precursors that enters in this metabolic pathway before the mitochondrial step, i.e. L ‐alanine (5 mM), L ‐lactate (2 mM), pyruvate (5 mM) and L ‐glutamine were decreased (p < 0·05). However, the gluconeogenic activity using glycerol (2 mM), which enters in the gluconeogenesis after the mitochondrial step was maintained. Taken together, the results suggest that the inhibition of LG promoted by SIH overcome the activation of this metabolic pathway promoted by IIH and could be attributed, at least in part, to its effect on mitochondrial function. Copyright © 2011 John Wiley & Sons, Ltd.     

Eye-tracking with nonhuman primates is now more accessible than ever before

Human and nonhuman primates rely almost exclusively on vision for social communication. Therefore, tracking eye movements and examining visual scan paths can provide a wealth of information about many aspects of primate social information processing. Although eye-tracking techniques have been utilized with humans for some time, similar studies in nonhuman primates have been less frequent over recent decades. This has largely been owing to the need for invasive manipulations, such as the surgical implantation of devices to limit head movement, which may not be possible in some laboratories or at some universities, or may not be congruent with some experimental aims (i.e., longitudinal studies). It is important for all nonhuman primate researchers interested in visual information processing or operant behavior to realize that such invasive procedures are no longer necessary. Here, we briefly describe new methods for fully noninvasive video eye-tracking with adult rhesus monkeys (Macaca mulatta). We also describe training protocols that require only ～30 days to accomplish and quality control measures that promote reliable data collection. It is our hope that this brief overview will reacquaint nonhuman primate researchers with the benefits of eye-tracking and promote expanded use of this powerful methodology.     

Enzymatic Activity,Sensitivity to Antifungal Drugs and <Emphasis Type="Italic">Baccharis dracunculifolia</Emphasis> Essential Oil by <Emphasis Type="Italic">Candida</Emphasis> Strains Isolated from the Oral Cavities of Breastfeeding Infants and in Their Mothers’ Mouths and Nipples

Candida strains can cause oral candidosis, as well as nipples candidosis and lead to premature weaning or yeast transmission. The aim of this study was to evaluate 51 Candida isolates obtained from the oral cavities of infants during breastfeeding and mothers’ oral cavities and nipples, their enzymatic activity and their sensitivity to amphotericin B, fluconazole and Baccharis dracunculifolia essential oil. Among the studied strains, 96.1% produced phospholipase and 78.4% produced proteinase. The antifungal resistance was only observed among isolates of C. albicans, for which three strains showed a resistant activity to fluconazole and one showed a resistant activity to amphotericin B. All strains were sensitive to B. dracunculifolia essential oil with MIC between 0.2 and 6.25 mg/ml. It was concluded that most of the strains showed significant enzymatic activity and were sensitive to amphotericin B and fluconazole. B. dracunculifolia essential oil inhibited the growth of all strains, including the ones resistant to commercial antifungal agents.