Cotrimoxazole enhances the in vitro susceptibility of Coccidioides posadasii to antifungals

The aim of the present study was to evaluate the effect of cotrimoxazole on the in vitro susceptibility of Coccidioides posadasii strains to antifungals. A total of 18 strains of C. posadasii isolated in Brazil were evaluated in this study. The assays were performed in accordance with the Clinical and Laboratory Standards Institute guidelines and the combinations were tested using the checkerboard method. The minimum inhibitory concentrations were reduced by 11, 2.4, 4.3 and 3.5 times for amphotericin B, itraconazole, fluconazole and voriconazole, respectively. Moreover, it was seen that cotrimoxazole itself inhibited C. posadasii strains in vitro. The impairment of folic acid synthesis may be a potential antifungal target for C. posadasii.     

Responses of coffee berry borer, Hypothenemus hampei (Ferrari)(Coleoptera: Scolytidae), to vertical distribution of methanol: ethanol traps

Captures of the coffee berry borer (CBB) Hypothenemus hampei (Ferrari) were assessed in traps in the field. IAPAR designed traps [plastic bottles (2 L) lured with methanol:ethanol (1:1) in a vessel] were placed either at 0.5, 1.0 and 1.5m high from the ground or simultaneously tested in the 2004 fructification season. Traps placed at the three heights trapped 5.5 times more CBB than the others, mostly at the traps placed at 0.5 m (75%). Treatments using the IAPAR designed trap placed at 1.2 m high; IAPAR trap with a white plastic plate above (IAPAR modified I) at 1.2 m high; IAPAR at 0.5 m high and two additional vessels at 1.0 and 1.5m high (IAPAR modified II) and T-163 trap [three red plastic cups (300 ml) and a red plastic plate as a cover] lured with M:E (1:1) at 1.2m height were compared in the vegetative (2005) and fructification (2006) periods. IAPAR modified II (dispenser vessels placed at 0.5, 1.0 and 1.5 m) trapped more beetles than the remaining types (2.72 times more beetles than IAPAR design); and IAPAR modified I traps trapped more beetles than T 163 and IAPAR traps in the vegetative period. In the reproductive period, IAPAR modified II trapped less beetles than IAPAR and IAPAR modified I. In 2007 vegetative season, IAPAR modified II trap were compared with IAPAR trap and trapped 2.8 times more beetles. The positive responses to a vertical distribution of the volatile attractants in the vegetative period of the planting allow the development of more efficient trapping systems for CBB.     

Structure-activity relationship of antileishmanials neolignan analogues

Twenty-two synthetic analogues of neolignans comprising beta-ketoethers and beta-ketosulfides were obtained from condensation reactions among beta-bromoketones and phenols or thiophenols, respectively, in basic solutions, and assayed in vitro for activity against intracellular Leishmania amazonensis and Leishmania donovani amastigotes, the causative agents of cutaneous and visceral leishmaniasis. The highest selective activity was found for compounds with sulfur bridges, whereas beta-ketosulphoxides and beta-ketosulphones had significantly less growth inhibitory activity. Compounds 2-[(4-chlorophenyl)thio]propan-1-one and 1-(3,4-dimethoxy)-2-[(4-methylphenyl)thio]propan-1-one were the most potent, inhibiting the growth parasite species by over 90% at microgram/mL, but only compound 1-(3,4-dimethoxy)-2-[(4-methylphenyl)thio]propan-1-one was selectively toxic to the parasites.     

MSX2 expression in the apical ectoderm ridge is regulated by an MSX2 and Dlx5 binding site.

The apical ectodermal ridge (AER) is a specialized ectodermal region essential for limb outgrowth. Msx2 expression patterns in limb development strongly suggest an important role for Msx2 in the AER. Our previous studies identified a 348-bp fragment of the chicken Msx2 gene with AER enhancer activity. In this study, the functions of four potential homeodomain binding TAAT sites in this enhancer were studied using transgenic mice and in vitro protein-DNA interactions. Transgenic studies indicate that the four TAAT sites are not redundant and that only the B-TAAT site is critical for AER enhancer activity. The expression patterns of Msx2 and Dlx5 genes in the AER suggest that they might be involved in the regulation of Msx2. In support of this hypothesis, we found that Msx2 and Dlx5 can bind to the B-TAAT site as well as to a fragment containing the D- and E-TAAT sites in the Msx2 AER enhancer sequences. (c)2002 Elsevier Science (USA).     

Cytotoxic withanolides from Acnistus arborescens

Three cytotoxic withanolides, two with new structures, were isolated from the leaves of Acnistus arborescens and their structures determined by a combination of 1D and 2D NMR, mass spectral, and molecular modeling studies. Dereplication analysis of the ethyl ether extract was useful for evaluating the components showing significant cytotoxic activity.     

Neural coding for the retrieval of multiple memory patterns

We investigate the retrieval dynamics in a feature-based semantic memory model, in which the features are coded by neurons of the Hindmarsh-Rose type in the chaotic regime. We consider the retrieval process as consisting of the synchronized firing activity of the neurons coding for the same memory pattern. The retrieval dynamics is investigated for multiple patterns, with particular attention to the case of overlapping memories. In this case, we hypothesize a dynamical nontransitive mechanism based on synchronization, that allows for a shared feature to participate in multiple memory representations. The problem of the choice of a cognitive plausible time-scale for the retrieval analysis is investigated by analyzing the information that can be inferred from finite-time analyses. Different types of indicators are proposed in order to evaluate the temporal dynamics of the neurons engaged in the retrieval process. We interpret the simulation results as suggestive of a role for chaotic dynamics in allowing for flexible composition of elementary meaningful units in memory representations.     

Transgenic mice with dominant negative PKC-theta in skeletal muscle: a new model of insulin resistance and obesity

Protein kinase C theta (PKC-theta) is the PKC isoform predominantly expressed in skeletal muscle, and it is supposed to mediate many signals necessary for muscle histogenesis and homeostasis, such as TGFbeta, nerve-dependent signals and insulin. To study the role of PKC-theta in these mechanisms we generated transgenic mice expressing a "kinase dead" mutant form of PKC-theta (PKC-thetaK/R), working as "dominant negative," specifically in skeletal muscle. These mice are viable and fertile, however, by the 6-7 months of age, they gain weight, mainly due to visceral fat deposition. Before the onset of obesity (4 months of age), they already show increased fasting and fed insulin levels and reduced insulin-sensitivity, as measured by ipITT, but normal glucose tolerance, as measured by ipGTT. After the 6-7 months of age, transgenic mice develop hyperinsulinemia in the fasting and fed state. The ipGTT revealed in the transgenic mice both hyperglycemia and hyperinsulinemia. At the molecular level, impaired activation of the IR/IRS/PI3K pathway and a significant decrease both in the levels and in insulin-stimulated activation of the serine/threonine kinase Akt were observed. Taken together these data demonstrate that over-expression of dominant negative PKC-theta in skeletal muscle causes obesity associated to insulin resistance, as demonstrated by defective receptor and post-receptorial activation of signaling cascade.     

Local tissue interactions across the dorsal midline of the forebrain establish CNS laterality

The mechanisms that establish behavioral, cognitive, and neuroanatomical asymmetries are poorly understood. In this study, we analyze the events that regulate development of asymmetric nuclei in the dorsal forebrain. The unilateral parapineal organ has a bilateral origin, and some parapineal precursors migrate across the midline to form this left-sided nucleus. The parapineal subsequently innervates the left habenula, which derives from ventral epithalamic cells adjacent to the parapineal precursors. Ablation of cells in the left ventral epithalamus can reverse laterality in wild-type embryos and impose the direction of CNS asymmetry in embryos in which laterality is usually randomized. Unilateral modulation of Nodal activity by Lefty1 can also impose the direction of CNS laterality in embryos with bilateral expression of Nodal pathway genes. From these data, we propose that laterality is determined by a competitive interaction between the left and right epithalamus and that Nodal signaling biases the outcome of this competition.     

Expression and functional analysis of Cititf1, an ascidian NK-2 class gene, suggest its role in endoderm development.

In solitary ascidians the fate of endoderm is determined at a very early stage of development and depends on cytoplasmic factors whose nature has not been determined. We have isolated a member of the NK-2 gene family, Cititf1, from the ascidian Ciona intestinalis, showing high sequence homology to mammalian TITF1. The Cititf1 gene was expressed in all endodermal precursors at the pregastrula and gastrula stages, and is thus the first specific regulatory endodermal marker to be isolated from an ascidian. Cititf1 expression was downregulated at the end of gastrulation to reappear at middle tailbud and larval stages in the most anterior and ventral parts of head endoderm, regions which give rise, after metamorphosis, to the adult endostyle, where Cititf1 mRNA was still present. Microinjection of Cititf1 mRNA into fertilized eggs resulted in tadpole larvae with abnormalities in head-trunk development consequent to the formation of excess endoderm, perhaps due to recruitment of notochord precursors to an endodermal fate. These data suggest that Cititf1 plays an important role in normal endoderm differentiation during ascidian embryogenesis.     

Histochemie des lipides complexes

Résumé Les auteurs, à la suite d'une série de récherches sur l'histochemie des lipides, donnent une nouvelle méthode pour la visualisation des seules groupes vic-glycols dans et en présence des lipides complexes, fondée sur le blocage aux halogènes des doubles liaisons. Le control histophotométrique démontre la spécificité et la sénsibilité de la méthode.

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Lipids histochemistryI. Detection of vic-glycols groups

Summary The authors proposed, in the course of a general investigation about the lipids, a improved method for the demonstration only of the vic-glycols groups in the lipids, founded on the halogenic block of ethylenic bounds. Histophotometrical control proved that this tecnic is specific and sensitive.