Connectivity in sol-gel silica glasses

In this work it is carried out a review on structural parameters related to the evaluation of pore connectivity of nanostructures. The work describes parameters and methods of evaluation of geometric parameters. The concepts of connectivity are applied to silica gels and glasses obtained from sol-gel process. The study of pores connectivity was carried out using a combination of geometric modeling and experimental evaluation of specific surface area and pore volume. The permeability of the pore structure is evaluated and a permeability geometric factor, Pg, is proposed.

Role of mast cell- and non-mast cell-derived inflammatory mediators in immunologic induction of synaptic plasticity

We have previously discovered a long-lasting enhancement of synaptic transmission in mammal autonomic ganglia caused by immunological activation of ganglionic mast cells. Subsequent to mast cell activation, lipid and peptide mediators are released which may modulate synaptic function. In this study we determined whether some mast cell-derived mediators, prostaglandin D2 (PGD2; 1.0 µM), platelet aggregating factor (PAF; 0.3 µM) and U44619 (a thromboxane analogue; 1.0 µM), and also endothelin-1 (ET-1; 0.5 µM) induce synaptic potentiation in the guinea pig superior cervical ganglion (SCG), and compared their effects on synaptic transmission with those induced by a sensitizing antigen, ovalbumin (OVA; 10 µg/ml). The experiments were carried out on SCGs isolated from adult male guinea pigs (200-250 g) actively sensitized to OVA, maintained in oxygenated Locke solution at 37oC. Synaptic potentiation was measured through alterations of the integral of the post-ganglionic compound action potential (CAP). All agents tested caused long-term (LTP; duration ³30 min) or short-term (STP; <30 min) potentiation of synaptic efficacy, as measured by the increase in the integral of the post-ganglionic CAP. The magnitude of mediator-induced potentiation was never the same as the antigen-induced long-term potentiation (A-LTP). The agent that best mimicked the antigen was PGD2, which induced a 75% increase in CAP integral for LTP (antigen: 94%) and a 34% increase for STP (antigen: 91%). PAF-, U44619-, and ET-1-induced increases in CAP integral ranged for LTP from 34 to 47%, and for STP from 0 to 26%. These results suggest that the agents investigated may participate in the induction of A-LTP

In vivo and in vitro effect of imipramine and fluoxetine on Na+,K+-ATPase activity in synaptic plasma membranes from the cerebral cortex of rats

The effects of in vivo chronic treatment and in vitro addition of imipramine, a tricyclic antidepressant, or fluoxetine, a selective serotonin reuptake inhibitor, on the cortical membrane-bound Na+,K+-ATPase activity were studied. Adult Wistar rats received daily intraperitoneal injections of 10 mg/kg of imipramine or fluoxetine for 14 days. Twelve hours after the last injection rats were decapitated and synaptic plasma membranes (SPM) from cerebral cortex were prepared to determine Na+,K+-ATPase activity. There was a significant decrease (10%) in enzyme activity after imipramine but fluoxetine treatment caused a significant increase (27%) in Na+,K+-ATPase activity compared to control (P<0.05, ANOVA; N = 7 for each group). When assayed in vitro, the addition of both drugs to SPM of naive rats caused a dose-dependent decrease in enzyme activity, with the maximal inhibition (60-80%) occurring at 0.5 mM. We suggest that a) imipramine might decrease Na+,K+-ATPase activity by altering membrane fluidity, as previously proposed, and b) stimulation of this enzyme might contribute to the therapeutic efficacy of fluoxetine, since brain Na+,K+-ATPase activity is decreased in bipolar patients.

Synaptic vesicle pool size, release probability and synaptic depression are sensitive to Ca2+ buffering capacity in the developing rat calyx of Held

The calyx of Held, a specialized synaptic terminal in the medial nucleus of the trapezoid body, undergoes a series of changes during postnatal development that prepares this synapse for reliable high frequency firing. These changes reduce short-term synaptic depression during tetanic stimulation and thereby prevent action potential failures during a stimulus train. We measured presynaptic membrane capacitance changes in calyces from young postnatal day 5-7 (p5-7) or older (p10-12) rat pups to examine the effect of calcium buffer capacity on vesicle pool size and the efficiency of exocytosis. Vesicle pool size was sensitive to the choice and concentration of exogenous Ca2+ buffer, and this sensitivity was much stronger in younger animals. Pool size and exocytosis efficiency in p5-7 calyces were depressed by 0.2 mM EGTA to a greater extent than with 0.05 mM BAPTA, even though BAPTA is a 100-fold faster Ca2+ buffer. However, this was not the case for p10-12 calyces. With 5 mM EGTA, exocytosis efficiency was reduced to a much larger extent in young calyces compared to older calyces. Depression of exocytosis using pairs of 10-ms depolarizations was reduced by 0.2 mM EGTA compared to 0.05 mM BAPTA to a similar extent in both age groups. These results indicate a developmentally regulated heterogeneity in the sensitivity of different vesicle pools to Ca2+ buffer capacity. We propose that, during development, a population of vesicles that are tightly coupled to Ca2+ channels expands at the expense of vesicles more distant from Ca2+ channels.

Discovery of Ascomycete characteristics in Sporothrix schenckii

Sporothrix schenckii has been studied by light microscopy, and also by transmission and scanning electron microscopy. Characteristics of Ascomycetes have been oibserved at the level of the cell-wall and in the synaptic system of the hyphae. Also the perfect state has been discovered. The four spored asei are formed directly from the mycelium and there is no fructification. Dolichoascus schenckii is the name suggested for this perfect state which constitutes a new genus of the Endomycetaceae.

Neurobiologia da Cannabis: do sistema endocanabinoide aos transtornos por uso de Cannabis

OBJETIVOS: Diante das lacunas na efetividade das terapêuticas para transtornos por uso de Cannabis, a droga ilícita mais consumida no mundo, este trabalho propõe-se a rever os conhecimentos sobre o substrato neuroanatômico, biomolecular e celular do sistema endocanabinoide, descrever os mecanismos de neuroplasticidade dependente dos canabinoides e relacioná-los com a neurobiologia dos transtornos por uso de Cannabis (abuso e dependência). MÉTODOS: Recorreu-se às bases de dados Medline, Scopus e ISI Web of Knowledge; as palavras-chave pesquisadas foram "Cannabis", "neurobiology", "endocannabinoid system", "endocannabinoids", "receptors, cannabinoid", "neuronal plasticity", "long-term synaptic depression", "long-term potentiation", "marijuana abuse" e "tetrahydrocannabinol". Foram incluídos 80 trabalhos nesta revisão. DISCUSSÃO: A distribuição neuroanatômica, celular e biomolecular do sistema endocanabinoide adequa-se perfeitamente às suas funções de neuromodulação (via neuroplasticidade e metaplasticidade), nomeadamente em vias relacionadas aos transtornos por uso de substâncias. Os canabinoides exógenos perturbam essas funções. CONCLUSÃO: O sistema endocanabinoide contribui para a definição de setpoints em diversas vias neuronais, incluindo vias cruciais na instalação de transtornos por uso de substâncias; com o uso de Cannabis, esses setpoints tornar-se-ão mais permissivos, facilitando os transtornos por uso de Cannabis. Os avanços no entendimento da neurobiologia da Cannabis abrem uma janela de oportunidades para novas estratégias terapêuticas nos transtornos por uso de Cannabis.

Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth) of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

Density estimates and conservation of Leopardus pardalis southernmost population of the Atlantic Forest

ABSTRACT Using camera traps and capture/recapture analyses we recorded the presence and abundance of cat species at Turvo State Park, in southern Brazil. Ocelot [Leopardus pardalis (Linnaeus, 1758)] population density was estimated for two areas of the park, with differing management profiles. Density estimates varied from 0.14 to 0.26 indiv. km2. Another five cat species were recorded at very low frequencies, precluding more accurate analyses. We estimate 24 to 45 ocelots occur in the reserve, which is probably too small for long-term maintenance of the population, if isolated. However, if habitat integrity and connectivity between the Park and the Green Corridor of Misiones is maintained, an estimated ocelot population of 1,680 individuals should have long-term viability.

Development of natural products as drugs acting on central nervous system

We have recenty studied several natural product constituents which have effects on the CNS. (1) Tetrahydropalmatine (THP) and its analogues were isolated from Corydalis ambigua and various species of Stephania. (+)-THP and (-)-THP posses not only analgesic activity, but also exert sedative-tranquillizing and hypnotic actions. Results of receptor binding assay and their pre-and post-synaptic effects on dopaminergic system indicate that (-)-THP and (-)-stepholidine are dopamine receptor antagonists while (+)-THP is a selective dopamine depletor. (2) 3-Acetylaconitine (AAC) is an alkaloid isolated from Aconitum flavum. The relative potency of analgesic action of AAC was 5.1-35.6 and 1250-3912 times that of morphine and aspirin, respectively. The analgesic effect of AAC was antagonized by naloxone, but was eliminated by reserpine. In monkeys, after AAC was injected for 92 days, no abstinence syndrome was seen after sudden AAC withdrawal or when challenged with nalorphine. (3) Huperzine A (Hup-A) is an alkaloid isolated from Huperzia serrata which was found to be a selective ChE inhibitor and could improve learning and retrieval process. Preliminary clinical studies showed that Hup-A improve short-and long-term memory in patients of cerebral arteriosclerosis with memory impairment. (4) Ranamargarin is a new tetradecapeptide isolated from the skin of the Chines frog Rana margaratae. This peptide may mainly act on NK-1 receptor.

Saponins from Swartzia langsdorffii: biological activities

The presence of saponins and the molluscicidal activity of the roots, leaves, seeds and fruits of Swartzia langsdorffii Raddi (Leguminosae) against Biomphalaria glabrata adults and eggs were investigated. The roots, seeds and fruits were macerated in 95% ethanol. These extracts exerted a significant molluscicidal activity against B. glabrata, up to a dilution of 100 mg/l. Four mixtures (A2, B2, C and D) of triterpenoid oleanane type saponins were chromatographically isolated from the seed and fruit extracts. Two known saponins (1 and 2) were identified as beta-D-glucopyranosyl-[alpha-L-rhamnopyranosyl-(1->3)- beta-D-glucuronopyranosyl-(1->3)]-3beta-hydroxyolean-12-ene-28 -oate, and beta-D-glucopyranosyl-(1->3)-beta-D-glucuronopyranosyl-(1 ->3)]-3beta-hydroxyolean-12-ene-28-oate, respectively. These two saponins were present in all the mixtures, together with other triterpenoid oleane type saponins, which were shown to be less polar, by reversed-phase HPLC. The saponin identifications were based on spectral evidence, including ¹H-¹H two-dimensional correlation spectroscopy, nuclear Overhauser and exchange spectroscopy, heteronuclear multiple quantum coherence, and heteronuclear multiple-bond connectivity experiments. The toxicity of S. langsdorffii saponins to non-target organisms was prescreened by the brine shrimp lethality test.

Genetic compatibility between Anopheles lesteri from Korea and Anopheles paraliae from Thailand

To assess differentiation and relationships between Anopheles lesteri and Anopheles paraliae we established three and five iso-female lines of An. lesteri from Korea and An. paraliae from Thailand, respectively. These isolines were used to investigate the genetic relationships between the two taxa by crossing experiments and by comparing DNA sequences of ribosomal DNA second internal transcribed spacer (ITS2) and mitochondrial DNA cytochrome c oxidase subunit I (COI) and subunit II (COII). Results of reciprocal and F1-hybrid crosses between An. lesteri and An. paraliae indicated that they were compatible genetically producing viable progenies and complete synaptic salivary gland polytene chromosomes without inversion loops in all chromosome arms. The pairwise genetic distances of ITS2, COI and COII between these morphological species were 0.040, 0.007-0.017 and 0.008-0.011, respectively. The specific species status of An. paraliae in Thailand and/or other parts of the continent are discussed.