Photodynamic Antimicrobial Chemotherapy in Aquaculture: Photoinactivation Studies of Vibrio fischeri

BACKGROUND: Photodynamic antimicrobial chemotherapy (PACT) combines light, a light-absorbing molecule that initiates a photochemical or photophysical reaction, and oxygen. The combined action of these three components originates reactive oxygen species that lead to microorganisms' destruction. The aim was to evaluate the efficiency of PACT on Vibrio fischeri: 1) with buffer solution, varying temperature, pH, salinity and oxygen concentration values; 2) with aquaculture water, to reproduce photoinactivation (PI) conditions in situ. METHODOLOGY/PRINCIPAL FINDINGS: To monitor the PI kinetics, the bioluminescence of V. fischeri was measured during the experiments. A tricationic meso-substituted porphyrin (Tri-Py(+)-Me-PF) was used as photosensitizer (5 µM in the studies with buffer solution and 10-50 µM in the studies with aquaculture water); artificial white light (4 mW cm(-2)) and solar irradiation (40 mW cm(-2)) were used as light sources; and the bacterial concentration used for all experiments was ≈10(7) CFU mL(-1) (corresponding to a bioluminescence level of 10(5) relative light units--RLU). The variations in pH (6.5-8.5), temperature (10-25°C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (≈7 log reduction). The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter. Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 µM of Tri-Py(+)-Me-PF. CONCLUSIONS/SIGNIFICANCE: If PACT is to be used in environmental applications, the matrix containing target microbial communities should be previously characterized in order to establish an efficient protocol having into account the photosensitizer concentration, the light source and the total light dose delivered. The possibility of using solar light in PACT to treat aquaculture water makes this technology cost-effective and attractive

EFFECT OF THE HEAT-MOISTURE TREATMENT ON THE ENZYMATIC SUSCEPTIBILITY OF CORN STARCH GRANULES

Normal and waxy corn starches were isolated, adjusted to different levels of moisture and heated at 100 degrees C for 16h. The heat treated starches were hydrolysed with alpha-amylase and amyloglucosidase. The starch samples were studied by determining their water-binding capacity, pasting properties, X-ray diffraction and by optical and scanning electron microscopy. The results showed that the heat-moisture treatment produced an increase in the degree of crystallinity of normal and waxy corn starches at the level of 18% moisture. This result, in conjunction with a significant decrease in the enzymatic susceptibility, suggested a rearrangement of the starch molecules with strengthening of the linkages within the granules. On the other hand, the heat-moisture treatment caused a rupture with further rearrangment of linkages within the grannies for normal and waxy corn starches adjusted to the 27% moisture level. This produced a certain degree of starch degradation increasing the accessible regions of the granule to amylolysis.47622322

Structural and physicochemical characteristics of lintnerized native and sour cassava starches

The comprehension of the structure of starch granules is important for the understanding of its physicochemical properties. Native and sour cassava starches after being analyzed with respect to their pasting properties and baking expansion capacity, were treated with 2.2 N HCl at 38 degreesC for a maximum of nine days. The starch granules remaining after lintnerization were analyzed for amylose content and intrinsic viscosity, by X-ray diffraction, scanning electron microscopy and chromatographic analysis. The results indicated that the acid hydrolysis on all starches occurred in two steps. The first one, with high hydrolysis rate, was characterized by a quick degradation of the amorphous part of the granules whereas the second step, with lower hydrolysis rate, was characterized by a higher resistance of the organized areas of the granules to acid treatment. Most of the amylose chains were found in the amorphous areas of starch granules only a small percentage was involved in the crystalline regions. The microscopic and chromatographic analysis demonstrated that the acid hydrolysis was not able to disrupt the entire granular crystalline structure. Fermented starch showed amylose and/or amylopectin chain fractions resistant to pullulanase, probably due to structural alterations during fermentation.541046947

The structure of waxy corn starch: Effect of granule size

The granules of waxy corn starch were isolated and various samples were separated by size and classified according to their average diameter in: non-separated granules (N), granules with diameter <15 mu m (S) and granules with diameter greater than or equal to 15 mu m (L). The samples were hydrolyzed by bacterial cr-amylase and fungal amyloglucosidase. The starch granules remaining after enzymatic hydrolysis were analysed by X-ray diffraction and optical and scanning electron microscopy. Sephadex G-50 gel permeation chromatography of the dissolved residues from the hydrolysis of the N and S samples was performed directly and after successive enzymatic digestion with pullulanase and beta-amylase. The results showed that the percentage of hydrolysis increased with a decrease in diameter. No apparent differences in waxy corn starch when observed under light and scanning electronic microscope were observed, regardless of diameter and enzyme action, although both large and small granules showed extensive surface corrosion after enzymatic attack. X-ray analysis suggested a decrease in the quantity of crystalline areas in the smaller granules, which would explain the high percentage of hydrolysis evidenced by these granules. The elution patterns of the alpha-glucans of both starches (N and S) were similar and reveled the presence of two fractions which were not susceptible to cr-amylase and amyloglucosidase attack suggesting that these fractions were involved in the waxy corn starch crystalline regions. Debranching with pullulanase followed by gel-permeation chromatography showed that the amylopectins from the starch granules studied contained three groups of unit chains instead of the two reported in the literature.50519319

Structural and physicochemical characteristics of lintnerized native and sour cassava starches

The comprehension of the structure of starch granules is important for the understanding of its physicochemical properties. Native and sour cassava starches after being analyzed with respect to their pasting properties and baking expansion capacity, were treated with 2.2 N HCl at 38 degreesC for a maximum of nine days. The starch granules remaining after lintnerization were analyzed for amylose content and intrinsic viscosity, by X-ray diffraction, scanning electron microscopy and chromatographic analysis. The results indicated that the acid hydrolysis on all starches occurred in two steps. The first one, with high hydrolysis rate, was characterized by a quick degradation of the amorphous part of the granules whereas the second step, with lower hydrolysis rate, was characterized by a higher resistance of the organized areas of the granules to acid treatment. Most of the amylose chains were found in the amorphous areas of starch granules only a small percentage was involved in the crystalline regions. The microscopic and chromatographic analysis demonstrated that the acid hydrolysis was not able to disrupt the entire granular crystalline structure. Fermented starch showed amylose and/or amylopectin chain fractions resistant to pullulanase, probably due to structural alterations during fermentation

Liderança em enfermagem psiquiátrica Liderazgo en enfermería psiquiátrica Leadership in psychiatric nursing

O processo de liderança em enfermagem psiquiátrica é uma temática que deve ser cuidadosamente abordada e amplamente discutida. Contudo, poucas são as fontes científicas acerca do assunto. Assim sendo, buscou-se através deste ensaio refletir a liderança e as suas várias formas de abordagem em psiquiatria ao longo dos tempos, sendo possível certificar sua evolução. A assistência de qualidade deve ser o objetivo único e primordial e a liderança na enfermagem psquiátrica deve estar baseada no reconhecimento das necessidades desta clientela e nas qualidades de sua equipe. Este muitas vezes constitui um desafio para os profissionais enfermeiros, permitindo um maior crescimento profissional. E é justamente o preparo do profissional que auxiliará no bom andamento do tratamento do paciente psiquiátrico, alcançando um resultado satisfatório<br>El proceso de liderazgo en enfermería psiquiátrica es un tema que debe ser cuidadosamente abordado y extensamente discutido. Sin embargo, pocas son las fuentes científicas referentes al tema. De esta manera, hubo una búsqueda a través de este trabajo sobre el liderazgo y sus varias formas de abordaje en psiquiatría a través de los tiempos, siendo posible certificar su evolución. La ayuda de calidad debe ser el único y primordial objetivo y el liderazgo del enfermero debe estar basada en el reconocimiento de las necesidades de la clientela y en las calidades del equipo. Tal reflexión muchas veces constituye un desafío para los enfermeros profesionales, permitiendole un crecimiento profesional mayor. Es exactamente la preparación del profesional que ayudará al buen curso del tratamiento del paciente psiquiátrico, alcanzando un resultado satisfactorio.<br>The process of leadership in psychiatric nursing is a thematic that must be carefully boarded and be widely argued. However, few are the scientific sources concerning the subject. In this way, it was seek through this work reflecting the leadership and its some forms of boarding in psychiatry through the times, being possible to certify its evolution. The quality assistance must be the only and primordial objective and the leadership of the nurse must be established in the recognition of the necessities of the clientele and in the qualities of the team. Such reflection many times constitutes a challenge for the professional nurses, allowing a bigger professional growth. It is exactly the preparation of the professional who will assist in the good course of the treatment of the psychiatric patient, reaching a satisfactory result