Effect of acetylcholine, pilocarpine, serotonin and adrenaline on the in vitro gastric motility of Hoplias malabaricus (Teleostei)

The in vitro effect of acetylcholine, pilocarpine, serotonina and adrenaline on gastric motility of the teleost Hoplias malabaricus was studied. The stomach of this specieshas spontaneous contractile activity, with no relationship between tension or frequency of contrations and fish weight. Acetylcholine reduced the frequency of contrations at higher concentrations, but had not effect at lower concentrations. The higher doses of this drug increased the tension and tonus of the contrations. Pilocarpine increased the frequency and tension of contractions at higher concentrations, but had not effect at lower concentrations, and increased tonus only at the concentration of 10-7 M. A significant correlation between the doses of acetylcholine and policarpine and tension of gastric contractions was found. Adrenaline and serotonina had not effect on the frequency, tension and tonus of the stomach contractions. The results obtained with acetylcholine and policarpine demonstrate that the stomach of H. malabaricus has muscarinic cholinoceptors. The results obtained with adrenaline and serptonin did not demonstrate the existence of adrenergic or serotonergic receptors in the stomach of this species.o efeito da acetilcolina, pilocarpina, serotonina e adrenalina na motilidade gástrica "in vitro" do teleósteo Hoplias malabaricus foi analisado. O estômago desta espécie apresenta uma atividade contrátil espontânea. Não se detectou nenhuma relação entre tensão ou frequência das contrações estomacais com o peso total dos peixes. A acetilcolina diminuiu a frequência das contrações nas concentrações 5 x 10-8 M e 10-7 M e aumentou a tensão e o tônus das contrações estomacais nestas mesmas concentrações. A pilocarpina aumentou a frequência das contrações estomacais nas concentrações 10-8 M, 5 x 10-8 M e 10-7 M, aumentou a tensão nas concentrações 5 x 10-8 M e 10-7 M e o tônus na concentração 10-7 M. A serotonina e a adrenalina não alteraram a frequência, tensão e tônus das contrações estomacais em nenhuma das concentrações utilizadas. Encontrou-se uma correlação significativa entre as doses de acetilcolina e pilocarpina e a tensão das contrações. Os resultados com acetilcolina e pilocarpina permitem concluir que o estômago de H. malabaricus possui receptores colinérgicos muscarínicos. Os resultados obtidos com adrenalina e serotonina não permitem demonstrar a existência de receptores adrenérgicos e serotoninérgicos no estômago desta espécie

Antimicrobial functionalized genetically engineered spider silk

Genetically engineered fusion proteins offer potential as multifunctional biomaterials for medical use. Fusion or chimeric proteins can be formed using recombinant DNA technology by combining nucleotide sequences encoding different peptides or proteins that are otherwise not found together in nature. In the present study, three new fusion proteins were designed, cloned and expressed and assessed for function, by combining the consensus sequence of dragline spider silk with three different antimicrobial peptides. The human antimicrobial peptides human neutrophil defensin 2 (HNP-2), human neutrophil defensins 4 (HNP-4) and hepcidin were fused to spider silk through bioengineering. The spider silk domain maintained its self-assembly features, a key aspect of these new polymeric protein biomaterials, allowing the formation of b-sheets to lock in structures via physical interactions without the need for chemical crosslinking. These new functional silk proteins were assessed for antimicrobial activity against Gram e Escherichia coli and Gram þ Staphylococcus aureus and microbicidal activity was demonstrated. Dynamic light scattering was used to assess protein aggregation to clarify the antimicrobial patterns observed. Attenuated-total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and circular dichroism (CD) were used to assess the secondary structure of the new recombinant proteins. In vitro cell studies with a human osteosarcoma cell line (SaOs-2) demonstrated the compatibility of these new proteins with mammalian cells.Fundação para a Ciência e a Tecnologia (FCT) - Bolsa de doutoramento (SFRH/BD/28603/2006); Chimera project (PTDC/EBB-EBI/109093/2008); NIH and Tissue Engineering Resource Center EB003210, P41 EB002520, DE017207

Detecção do gene mecA em estafilococos coagulase negativa resistentes à oxacilina isolados da saliva de profissionais da enfermagem Detection of mecA gene in oxacillin-resistant coagulase-negative staphylococci isolated from the saliva of nursing professionals

Estafilococos coagulase negativa estão frequentemente associados às infecções nosocomiais e os profissionais da saúde podem ser reservatório e dissemina-los no hospital e comunidade. O objetivo desse estudo foi identificar espécies de estafilococos coagulase negativa isolados da saliva de profissionais da enfermagem, determinar o perfil de resistência e detectar o gene mecA. Foram selecionados 100 estafilococos coagulase negativa, sendo 41 identificados como Staphylococcus epidermidis, 25 Staphylococcus saprophyticus, 18 Staphylococcus haemolyticus, 8 Staphylococcus cohnii, 4 Staphylococcus lugdunenses, 3 Staphylococcus capitis, e 1 Staphylococcus Simulans. Desses, 32% apresentaram resistência à oxacilina, 84,4% à mupirocina, 32% à cefoxitina, e todos sensíveis a vancomicina. Dos estafilococos coagulase negativa resistentes à oxacilina, 93,7% desenvolveram-se no agar oxacilina (6µg/ml) e o gene mecA foi detectado em 75%. Os resultados sinalizam que maiores investimentos devem ser direcionados a identificação das espécies de estafilococos coagulase negativa nas instituições de saúde e na comunidade.<br>Coagulase-negative staphylococci are frequently associated with nosocomial infections, and healthcare professionals can be reservoirs and spread them in hospitals and in the community. The aim of this study was to identify species of coagulase-negative staphylococci isolated from the saliva of nursing professionals, determine the resistance profile and detect the mecA gene. One hundred coagulase-negative staphylococci were selected: 41 were identified as Staphylococcus epidermidis, 25 as Staphylococcus saprophyticus, 18 as Staphylococcus haemolyticus, eight as Staphylococcus cohnii, four as Staphylococcus lugdunenses, three as Staphylococcus capitis and one as Staphylococcus simulans. Of these, 32% presented oxacillin resistance, 84.4% mupirocin resistance and 32% cefoxitin resistance, and all were vancomycin sensitive. Among the oxacillin-resistant coagulase-negative staphylococci, 93.7% developed in oxacillin agar (6µg/ml) and the mecA gene was detected in 75%. The results indicate that higher investments should be directed towards identifying coagulase-negative staphylococcus species in healthcare institutions and in the community