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Water Dilution (water + dilution)
Selected AbstractsCharacterization of specific egg yolk immunoglobulin (IgY) against mastitis - causing Staphylococcus aureusJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2008Y.-H. Zhen Abstract Aims:, To evaluate the in vitro activity of egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus. Methods and Results:, Specific IgY was produced by immunizing hens with formaldehyde-killed Staph. aureus, using a bacterial strain known to cause mastitis. The IgY, of 94% purity, was obtained from yolks by water dilution, salt precipitations, ultrafiltration and gel filtration. ELISA indicated that the IgY produced was specific to the antigen and five Staph. aureus isolates obtained from mastitic cows. The growth of Staph. aureus was inhibited by specific IgY at concentrations from 1 to 10 mg ml,1 in a dose-dependent manner. The phagocytosis of Staph. aureus by milk macrophages was enhanced in the presence of specific IgY with the highest phagocytic percentage being 30% higher than that without IgY (P < 0·05). Conclusions:, The specific IgY against mastitis-causing Staph. aureus inhibited the growth of Staph. aureus and enhanced the phagocytosis of Staph. aureus by milk macrophages. Significance and Impact of the Study:, Specific IgY would be a potential treatment for bovine mastitis. [source] Radio transmitters do not affect the body condition of Savannah Sparrows during the fall premigratory periodJOURNAL OF FIELD ORNITHOLOGY, Issue 4 2009Lauren F. Rae ABSTRACT Radio telemetry can be a valuable tool for studying the behavior, physiology, and demography of birds. We tested the assumption that radio transmitters have no adverse effects on body condition in an island population of Savannah Sparrows (Passerculus sandwichensis). To assess possible changes in condition, 20 radiotagged and 25 nontagged Savannah Sparrows were captured and recaptured throughout the postfledging period. We used four measures of condition: mass, an index of fat free dry mass (measured via heavy water dilution), pectoral muscle depth (measured via ultrasound imaging), and an index of fat mass (measured via heavy water dilution). Using both a generalized linear modeling framework and paired design, we found no significant differences in the body condition of radiotagged and nontagged adults and juveniles. Thus, our results provide evidence that radiotransmitters have no effect on the condition of Savannah Sparrows during the premigratory period. RESUMEN La radiotelemetría puede ser una herramienta valiosa para estudiar la conducta, fisiología y demografía de aves. Utilizando una población de gorriones (Passerculus sandiwichensis), pusimos a prueba el postulado de que los radiotransmisores no tienen efecto adverso sobre la condición corporal de las aves. Para determinar el posible efecto en la condición de los pájaros, capturamos y recapturamos 20 individuos con radiotransmisores y 25 individuos sin estos, durante el periodo de post-volantones. En el trabajo utilizamos cuatro medidas de condición: masa, un índice de masa-seca sin grasa (medida a través de una dilución de agua pesada), profundidad de los músculos pectorales (determinado con una máquina de ultrasonido) y un índice de masa de lípidos (medida vía una dilución de agua pesada). Utilizando tanto un andamiaje con modelo linear generalizado y un diseño pareado, no encontramos diferencias significativas en la condición corporal entre los adultos y juveniles con o sin transmisores. Nuestros resultados proveen evidencia de que los radiotransmisores no tienen efecto adverso en la condición de los gorriones estudiados durante el periodo migratorio. [source] Evaluation of recovery methods to detect faecal streptococci in polluted watersLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2001Massa Aims: This paper compares the faecal streptococci count on 25 samples of polluted waters obtained with three techniques: most probable number (MPN), membrane filtration (MF) and pour plate (PP) methods. Although the PP method is a simple technique, familiar to water bacteriologists, it is not recommended in the international methods. Methods and Results: For the MPN method, azide dextrose broth and ethyl violet azide broth were employed. For the MF technique, Millipore filters were placed onto azide maltose agar (KF agar), while for the PP method, 1 ml of a decimal water dilution was added to (Kennel Faecal) KF medium. Regression analysis and Friedman's ANOVA were performed to determine the relationship between faecal streptococci counts obtained with the three techniques. Statistical analysis of the results showed that the MPN, MF and PP techniques were equally valid with respect to faecal streptococci enumeration in polluted waters. Conclusions: Since the PP method was found to be as good as the other techniques, it may be preferred in polluted waters. It is more economical in terms of both time and materials than the MPN count, and it is as accurate as the MF count. Significance and Impact of the Study: This study indicates that the PP method, although not recommended internationally, is a reliable alternative to MF and MPN. [source] Atmospheric CO2 concentration does not directly affect leaf respiration in bean or poplarPLANT CELL & ENVIRONMENT, Issue 11 2001S. Jahnke Abstract It is a matter of debate if there is a direct (short-term) effect of elevated atmospheric CO2 concentration (Ca) on plant respiration in the dark. When Ca doubles, some authors found no (or only minor) changes in dark respiration, whereas most studies suggest a respiratory inhibition of 15,20%. The present study shows that the measurement artefacts , particularly leaks between leaf chamber gaskets and leaf surface, CO2 memory and leakage effects of gas exchange systems as well as the water vapour (,water dilution') effect on DCO2 measurement caused by transpiration , may result in larger errors than generally discussed. A gas exchange system that was used in three different ways , as a closed system in which Ca increased continuously from 200 to 4200 mmol (CO2) mol -1 (air) due to respiration of the enclosed leaf; as an intermittently closed system that was repeatedly closed and opened during Ca periods of either 350 or 2000 mmol mol -1, and as an open system in which Ca varied between 350 and 2000 mmol mol -1, is described. In control experiments (with an empty leaf chamber), the respective system characteristics were evaluated carefully. When all relevant system parameters were taken into account, no effects of short-term changes in CO2 on dark CO2 efflux of bean and poplar leaves were found, even when Ca increased to 4200 mmol mol -1. It is concluded that the leaf respiration of bean and poplar is not directly inhibited by elevated atmospheric CO2. [source] | ||||||||||