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Sporulation in distilled water   总被引:6,自引:0,他引:6       下载免费PDF全文
Spores are formed when vegetative cells of sporing aerobes are shaken with distilled water at 37°. These spores are derived from the small number of cells which survive lysis. The sporulation process involves increase and concentration of solid material in the cell, and is achieved at the expense of the products of lysis of 80 to 90 per cent of the resuspended cells.  相似文献   

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The calculated freezing point depression of freshly excised boiled mammalian tissue is approximately the same as that of plasma. The boiling procedure was chosen to eliminate the influence of metabolism on the level of the freezing point depression. Problems created by the boiling, such as equilibrium between tissue and diluent, change in activity coefficient by dilution, and loss of CO(2) content, are discussed. A frozen crushed tissue homogenate is hypertonic to plasma. Boiling and dilution of such hypertonic homogenate exposed to room temperature for 5 to 15 minutes did not produce significant or unexplicable decreases in its osmotic activity. Moreover, freezing and crushing of a boiled diluted tissue did not produce any increase of the isoosmotic level of freezing point depression. It is possible to explain these data either with the hypothesis of hypertonic cell fluid or with that of isotonic cell fluid. In the case of an assumed isotonic cell fluid, data can be explained with one assumption, experimentally backed. In the case of an assumed hypertonic theory data can be explained only with the help of at least three ad hoc postulates. The data support the validity of the classical concept which holds that cell fluid is isotonic to extracellular fluid.  相似文献   

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Summary The quantitative growth of Pseudococcomyxa adhaerens on glass cover slips in distilled water has been studied. Growth is limited by the supply of inorganic nutrients. Regular replacement of the distilled water gives an increase in the growth rate. The light intensity for maximum growth is a function of the nutrient supply. In a culture solution the rate of growth is about 8 times as great as in distilled water, and the limiting light intensity is increased to 400 lux from 100 lux.  相似文献   

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A theoretical model for dry blood smears is investigated. Circular elements with normally distributed radii and ellipses are considered. The differences in diffraction pattern of sparse and dense smears are explained. The theory is supported by some recordings by means of a simple photoelectric device. A method for calculation of a distribution measure of the radii is suggested.  相似文献   

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Refractoriness for bronchial provocation frequently occurs after different challenge tests used to assess bronchial hyperresponsiveness in asthmatic patients. We investigated whether histamine inhalation could cause refractoriness for bronchoconstriction induced by ultrasonically nebulized distilled water (UNDW) and whether histamine causes tachyphylaxis for a subsequent histamine challenge in nine stable asthmatic patients. Preinhalation of histamine induced a significant diminished bronchoconstrictor response to UNDW cumulative dose of inhaled UNDW causing a 20% fall in forced expired volume in 1 s. The mean increased from 3.5 +/- 0.8 to 11.8 +/- 2.6 (SE) ml after histamine challenge (P less than 0.01). However, repeated inhalation of histamine did not change the bronchoconstrictor response to histamine within 1 h after rechallenge (P greater than 0.5). The magnitude of refractoriness for UNDW inhalation after preinhalation of histamine was correlated to the bronchoconstrictor response to histamine (r = 0.73, P less than 0.05). We conclude that inhaled histamine can induce refractoriness for UNDW, which seems to be related to the degree of bronchial hyperresponsiveness.  相似文献   

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Selected prisoners, most of them with severe character disorders, are permitted to serve the remaining portion of their sentence on parole in the community on condition that they be patients in psychotherapy at a psychiatric clinic created in 1953 for this purpose. Nearly all the patients begin without personal motivation for such treatment. Attendance has been attained because parole officers are assigned to the task of enforcing attendance. Coercion can bring these reluctant patients to expose themselves to treatment, but staff members then have the task to overcome hostility, combat extensive rationalizations, and transform an initially poor rapport into patient participation in working through major personality change. This clinic provides an interesting laboratory for the development of a psychiatric treatment program for adults who have not responded well to a great variety of forms of correctional care.  相似文献   

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Summary It is found that if distilled water is allowed to flow through the leaves of terrestrial plants (Achillea millefolium, Chenopodium album, Rumex acetosella, Ficaria verna), the protoplasm of the cells exhibits increased fluidity. The terrestrial plants thus react in the same way as the earlier investigatedHelodea. The cause is not the absence of nutrient salts or of microelements, since nutrient solutions prepared from distilled water have the same effect. The cause is instead the absence of the fluidity-active substances that have earlier been demonstrated in the soil fluid, and which derive from plants.The effect persists as long as the leaves take up distilled water, but disappears gradually (after 1–3 days) when the uptake has ceased. It is assumed that the return to the normal fluidity value is due to production of fluidity-decreasing substances by the leaf cells. The changes—the increase in fluidity and the subsequent decrease—suggest the existence of a system of equilibrium, which regulates the fluidity value.The expenses of the present investigation were defrayed by a grant from the Science Research Council of Sweden.  相似文献   

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Quantification of hematozoa in blood smears   总被引:9,自引:0,他引:9  
Ten thin blood smears from mourning doves (Zenaida macroura) infected with Haemoproteus maccallumi were examined by each of two observers using identical techniques and microscopy in an attempt to delineate the factors necessary to provide an accurate estimate of the number of parasites/n erythrocytes. The number of erythrocytes examined must be actually counted, not estimated from extrapolated partial counts or from the number of fields of view examined. Doubling the number of erythrocytes counted (1) decreased the overdispersed frequency distribution patterns in only 25% of the replicate counts for numbers of H. maccallumi/100 erythrocytes for a series of 2,000 versus 4,000 erythrocytes counted; and (2) did not significantly increase the accuracy for determining parasite intensities. Thus, the number of erythrocytes that must be counted to determine parasite intensities could be considerably reduced from the 10,000 or 20,000 estimated for most studies, and still provide an accurate determination of the number of parasites/n erythrocytes in datasets collected from hosts with moderate to high levels of parasitemia. This resulted in a decreased amount of time expended by the observer on each blood smear examined. With two equivalently trained individuals, differences between observers examining the same blood smears were minimal. This study suggests an approach by which a more standardized methodology for quantifying blood parasite intensities could be developed.  相似文献   

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Some methods for keeping the fungal Culture Collection have been used. However, the choice of either one on the basis that must ensure the cultural genetic stability and its phenotipic characteristics. In this work the preservation method in distilled water recognized in the literature as a single, economic and certain method that guarantie the survival of fungus cultures for long periods was used. 26 strains of generus and species: Aspergillus niger, Aspergillus candidus, Fusarium sp., Fusarium moniliforme, Mucor griseocyanum, Syncephalastrum sp., Trichoderma sp., Trichoderma harzianum and Trichoderma koningii were preserved. Enough inoculum from well developed cultures (mainly spores and hyphae) poured in flasks with sterile distilled water warranted a 100% of survival of those microorganisms for two years. At the same time no apparent changes were observed in respect to morphology and macroscopic features.  相似文献   

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