Rehydration of Dried Mushroom Specimens With Aerosol OT for Scanning Electron Microscopy

Morphological, anatomical and ultrastructural characteristics are important for taxonomical and phylogenetic studies of fungi. For scanning electron microscopy, usually only dry voucher specimens are available. For dried plant material, Aerosol OT has been shown to be a suitable rehydration agent for SEM preparation. For swelling and stabilization of fungal cells, however, this simple method does not yield satisfactory results. Here, we show that a combination of Aerosol OT with ultrasonic bath and rehydration in a vacuum desiccator is a good method to distend fungal cells like basidiospores, pleuro- and cheilocystidia for SEM analysis. Tissues of several species of Agaricomycetes with diverse morphological structures were exposed to the treatment. Diverse concentrations of Aerosol OT as well as treatments in an ultrasonic bath and a vacuum desiccator were tested to optimize the surface reconstruction and to reduce preparation artefacts. The evaluated rehydration method is a cheap, quick and nontoxic method to prepare dried specimens of fungal cells for SEM analysis.

Cytotoxic, antimicrobial and healing activity of the Jatropha gossypiifolia L extract.

RESUMOObjetivo: investigar o potencial citotóxico, antimicrobiano e cicatrizante de extratos das folhas, galhos e caule da J. gossypiifolia L. Método: estudo quantitativo, experimental. Os extratos foram obtidos por maceração em etanol, concentrados em evaporador rotatório e secos em dessecador a vácuo. Na análise, realizaram-se testes de prospecção fitoquímica; citotoxidade; microdiluição em caldo e Scratch assay. Entre os metabólitos detectados, estiveram: taninos, esteroides, flavonoides, flavonas, xantonas. Resultados: o extrato do caule apresentou viabilidade celular acima de 80%. As folhas foram moderadamente citotóxicas e os galhos apresentaram ausência de viabilidade celular. Os extratos inibiram o crescimento de S. aureus, S. epidermidis e P. aeruginosa em diferentes concentrações. O Scratch assay evidenciou que a fração metanólica das folhas propiciou a migração celular em 45% a mais do que o controle. Conclusão: estudos com esta espécie vegetal devem ser continuados para isolamento do princípio ativo, visando à produção de um fitoterápico cicatrizante de feridas. Descritores: Cicatrização; Enfermagem; Citoxidade; Plantas Medicinais.ABSTRACTObjective: to investigate the cytotoxic, antimicrobial and cicatrizant potential of extracts of leaves, branches and stem of J. gossypiifolia L. Method: quantitative, experimental study. The extracts were obtained by maceration in ethanol, concentrated in a rotary evaporator and dried in a vacuum desiccator. In the analysis, phytochemical prospecting; cytotoxicity; microdilution in broth and Scratch assay tests were performed. Among the detected metabolites, were: tannins, steroids, flavonoids, flavones, xanthones. Results: the stem extract presented cell viability above 80%. The leaves were moderately cytotoxic and the branches showed no cell viability. The extracts inhibited the growth of S. aureus, S. epidermidis and P. aeruginosa at different concentrations. Scratch assay showed that the methanolic fraction of the leaves allowed the cellular migration in 45% more than the control. Conclusion: studies with this plant species should be continued for isolation of the active principle, aiming at the production of a wound healing phytotherapic. Descriptors: Healing; Nursing; Citotoxicity; Medicinal Plants.RESUMENObjetivo: investigar el potencial citotóxico, antimicrobiano y cicatrizante de los extractos de las hojas, ramas y el tallo de J. gossypiifolia L. Método: estudio cuantitativo, experimental. Los extractos fueron obtenidos por maceración en etanol, concentrados en evaporador rotatorio y seco en desecador al vacuo. En el análisis, se realizaron pruebas de prospección fitoquímica; citotoxicidad; microdilución en caldo y Scratch asay. Entre los metabolitos detectados, estuvieron: taninos, esteroides, flavonoides, flavonas, xantonas. Resultados: el extracto del tallo presentó viabilidad celular por encima del 80%. Las hojas fueron moderadamente citotóxicas y las ramas presentaron ausencia de viabilidad celular. Los extractos inhibieron el crecimiento de S. aureus, S. epidermidis y P. aeruginosa en diferentes concentraciones. El Scratch assay evidenció que la fracción metanólica de las hojas propició la migración celular en un 45% más que el control. Conclusión: estudios con esta especie vegetal deben ser continuados para aislamiento del principio activo, visando la producción de un fitoterápico cicatrizante de heridas. Descriptores: La Curación; Enfermería; Citotoxicidad; Plantas Medicinales.

Evaluation and identification of walnut heartwood extractives for protection of poplar wood

Walnut (Juglans regia L.) heartwood extractives were identified and their potential for protection of poplar wood was evaluated. Test specimens were prepared from poplar wood (Populus nigra L.) to meet BS 838:1961 requirements. Samples were impregnated with heartwood extractive solution (1.5, 2.5, and 3.5% w/w in ethanol-toluene), followed by 5 hours vacuum desiccator technique to reach complete saturation. Impregnated specimens were exposed to white-rot fungus (Trametes versicolor) for 14 weeks according to BS 838:1961 applying the kolle-flask method. The weight loss of samples was determined after exposure to white-rot fungus. The highest weight loss (36.96%) was observed for untreated control samples and the lowest weight loss (30.40%) was measured in samples treated with 1.5% extractives solution. The analyses of the extracts using GC/MS indicated that major constituents are benzoic acid,3,4,5-tri(hydroxyl) and gallic acid (44.57 %). The two toxic components in the heartwood are juglone (5.15 %) and 2,7-dimethylphenantheren (5.81 %).

Effect of storage in aqueous environments on polymer–metal interfacial fracture

The effect of environmental exposure on the fracture characteristics of two polymer–metal interfaces was measured using a four-point bend delamination test. Films of high-molecular-weight polymethylmethacrylate (PMMA) resin were spin-cast on metal-coated silicon wafer substrates, for which the metal was either titanium or aluminum. Sandwich beam specimens were fabricated and stored in one of the following conditions prior to the bending tests: vacuum desiccator at 25 °C, vacuum desiccator at 65 °C, distilled water at 25 °C, or distilled water at 65 °C. Load–displacement behavior measured during bending revealed significant differences between the delamination characteristics of the two PMMA–metal interfaces after vacuum exposure which were eliminated after the degrading effects of water exposure. Three distinctive load–displacement behaviors were observed: plateau, fracture at a single load; R-curve, fracture at increasing load with crack extension; and stick-slip, cycles of gradual load increase and sudden load drop with crack extension. PMMA–Al samples stored in vacuum desiccator at 25 °C exhibited R-curve fracture and the largest average crack driving force, GC, 12.2 (±0.5) J/m2, of all samples tested. After storage in 25 °C water, these PMMA–Al samples exhibited stick-slip fracture and GC decreased to 7.1 (±2.6) J/m2; storage in 65 °C water further decreased GC to 2.1 (±0.7) J/m2. PMMA–Ti samples exhibited stick-slip fracture after storage in vacuum desiccator at 25 °C, with an average GC of 8.0 (±2.6) J/m2; storage in 65 °C water resulted in a transition to plateau fracture and a decrease in GC to 1.6 (±0.3) J/m2. The initial difference and subsequent similarity are interpreted in terms of surface roughness and hydrolysis, respectively.

Viability of Pollen of Two Fruit Crop Cacti of the Genus Hylocereus Is Affected by Temperature and Duration of Storage

Hylocereus undatus (Haw.) and H. polyrhizus (Weber) are new fruit crops of the Cactaceae. In Israel, flowers of the two species, which are self-incompatible, are hand cross-pollinated. In order to ensure a current supply of compatible pollen and guarantee good yields, we have developed a procedure for long-term storage of pollen. Pollen for storage was collected in the evening or in the morning. Its moisture content ranged between 45% to 50% in the evening and between 18% to 22% in the morning. Pollen was first dehydrated in a vacuum desiccator until the moisture content was reduced to 5% to 10% and then stored at various temperatures (+4, -18, -70, -196 °C) for 3 or 9 months, after which it was used for cross-pollination. Percent fruit set and fruit fresh weight (FW) were affected by the temperature but not the duration of pollen storage; storage at +4 °C reduced fruit set, fruit FW, and seed number more than did storage at subfreezing temperatures. The FW of fruits produced by frozen pollen was similar to that produced by fresh pollen in commercial orchards. The rate of seed germination was high (≈90%) regardless of the temperature during pollen storage.

Viability of Pollen of Two Fruit Crop Cacti of the Genus Hylocereus Is Affected by Temperature and Duration of Storage

Hylocereus undatus (Haw.) and H. polyrhizus (Weber) are new fruit crops of the Cactaceae. In Israel, flowers of the two species, which are self-incompatible, are hand cross-pollinated. In order to ensure a current supply of compatible pollen and guarantee good yields, we have developed a procedure for long-term storage of pollen. Pollen for storage was collected in the evening or in the morning. Its moisture content ranged between 45% to 50% in the evening and between 18% to 22% in the morning. Pollen was first dehydrated in a vacuum desiccator until the moisture content was reduced to 5% to 10% and then stored at various temperatures (+4, –18, –70, –196 °C) for 3 or 9 months, after which it was used for cross-pollination. Percent fruit set and fruit fresh weight (FW) were affected by the temperature but not the duration of pollen storage; storage at +4 °C reduced fruit set, fruit FW, and seed number more than did storage at subfreezing temperatures. The FW of fruits produced by frozen pollen was similar to that produced by fresh pollen in commercial orchards. The rate of seed germination was high (≈90%) regardless of the temperature during pollen storage.

Anisotropie Contraction of Cortical Bone Caused by Dehydration of Samples of the Bovine Femur in Vitro

Cortical bone from the bovine femur has been studied to determine any changes in dimensions that might be caused by dehydration and subsequent rehydration of the samples. Nine control and ten embalmed axially oriented parallelepiped samples were produced with nominal dimensions of 5 × 5 × 30 mm. Sequences of oven drying and rehydration were studied, before dehydration in a vacuum desiccator prior to determining ash weights. Vacuum dehydration caused anisotropic shrinkage with statistically different (p < 0.00015) mean strains of 9200, 27000 and 40200 microstrain in the axial, circumferential and radial directions respectively. The corresponding mean strains for the embalmed samples were 7200, 21400 and 34000 microstrain (p < 0.000 15). These strains are notably greater than the typically quoted 3000 microstrain peak associated with normal physiological activities. Rehydration of either the control or embalmed samples in isotonic saline did not reproduce the original radial or circumferential dimensions. Due to the small range of ash weights from 69.8 to 75.2 per cent, no meaningful correlation between ash weight and shrinkage could be extracted from the data. These findings have a potentially dramatic impact upon the design and conduct of all in vitro studies that use bone, whether fresh or embalmed.