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141.
Hyalomma anatolicum anatolicum ticks infected with Theileria annulata were partially fed on rabbits and then ground up with tissue culture medium. The ground up ticks were treated by centrifugation at 100 g, filtration through membranes of 8 μm pore diameter and centrifugation on a discontinuous density gradient of Percoll. Counts of sporozoites and tick debris were made from Giemsa stained slides of samples at each stage of the separation. Debris was removed during light centrifugation and filtration at a greater rate than sporozoites. After filtration approximately 41% of the original sporozoites remained in the suspension. After density gradient centrifugation most sporozoites were found in a distinct zone, at approx. 1·08 g/cm3 density, separate from most dense debris and light debris and soluble contaminants. After this final centrifugation approximately 24% of the original sporozoites remained in the recovered suspension. 相似文献
142.
Legionella micdadei is a recently described opportunistic pulmonary pathogen that produces an acute, suppurative pneumonia in patients receiving steroid therapy. Most prospective diagnoses have been made by open lung biopsy. We present a case in which the diagnosis was made from cytologic material. The clinicopathologic features of L. micdadei pneumonia are discussed, and criteria for diagnosis from cytologic specimens are presented. 相似文献
143.
Ernest G. Walker 《American journal of physical anthropology》1983,60(4):499-503
The identification of the treponemas among prehistoric Amerindian populations is problematic. This paper presents the evidence for the presence of cardiovascular disease of syphilitic origin on the Plains of North America during prehistoric times. Comparative data from modern populations is used to arrive at a diagnosis. 相似文献
144.
We developed a biphasic culture system consisting of 4 ml of brucella agar (BA) and 6 ml of brucella broth (BB) in 25-cm2 tissue culture flasks, which were incubated in air (BB/BAa) or in a gas mixture of 5% O2, 10% CO2, and 85% N2 (BB/BAg). These media were also used with a supplement consisting of ferrous sulfate, sodium metabisulfite, and sodium pyruvate and incubated as above (FB/FAa and FB/FAg, respectively). Highly satisfactory growth of Campylobacter jejuni 301 was obtained with all medium-gas phase combinations provided that the number of viable cells in the inoculum was large (greater than or equal to 10(6)/ml). The use of FB/FAa permitted the inoculum to be reduced to 100 cells per ml. With an adjusted gas phase (BB/BAg and FB/FAg), near-optimal growth was obtained from an inoculum of 1 to 10 cells per ml. Under most of these conditions the generation time was approximately 90 min. During the logarithmic growth phase, the cells retained their typical spiral morphology and high motility. These media also proved to be highly satisfactory for the cultivation of fresh isolates as well as other stock strains of Campylobacter. When the broth phase of the cultures, after addition of 15% glycerol, was quickly frozen and maintained at -70 degrees C, all strains thus far examined were readily recoverable and satisfactorily cultivated without additional passage. 相似文献
145.
We used electron microscopy and serum blocking power tests to determine the phenotypes of 47 phage P1 amber mutants that have defects in particle morphogenesis. Eleven mutants showed head defects, 30 showed tail defects, and 6 had a defect in particle maturation (which could be either in the head or in the tail). Consideration of previous complementation test results, genetic and physical positions of the mutations, and phenotypes of the mutants allowed assignment of most of the 47 mutations to genes. Thus, a minimum of 12 tail genes, 4 head genes, and 1 particle maturation gene are now known for P1. Of the 12 tail genes, 1 (gene 19, located within the invertible C loop) codes for tail fibers, 6 (genes 3, 5, 16, 20, 21, and 26) code for baseplate components (although one of these genes could code for the tail tube), 1 (gene 22) codes for the sheath, 1 (gene 6) affects tail length, 2 (genes 7 and 25) are involved in tail stability, and 1 (gene 24) either codes for a baseplate component or is involved in tail stability. Of the four head genes, gene 9 codes for a protein required for DNA packaging. The function of head gene 4 is unclear. Head gene 8 probably codes for a minor head protein, whereas head gene 23 could code for either a minor head protein or the major head protein. Excluding the particle maturation gene (gene 1), the 12 tail genes are clustered in three regions of the P1 physical genome. The four head genes are at four separate locations. However, some P1 head genes have not yet been detected and could be located in two regions (for which there are no known genes) adjacent to genes 4 and 8. The P1 morphogenetic gene clusters are interrupted by many genes that are expressed in the prophage. 相似文献
146.
When intact mesophyll chloroplasts of Zea mays var Kelvedon Glory were illuminated, activation of NADP-malate dehydrogenase occurred. Activity declined rapidly on darkening. Light activation of the enzyme was very much greater in the presence of pyruvate (~10- to 20-fold) than with the electron acceptors 3-phosphoglycerate or oxaloacetate present (~2-fold). Following preillumination in the presence of pyruvate, addition of 3-phosphoglycerate, oxaloacetate, or nitrite substantially diminished the activity of NADP-malate dehydrogenase. In these circumstances, with pyruvate and 3-phosphoglycerate present, activity could be restored by the addition of nigericin or dihydroxyacetone phosphate. Nigericin also restored activity with both oxaloacetate and pyruvate present. The effect of nitrite was more marked in the presence of low concentrations of DCMU.
These observations are discussed in terms of the dependence of enzyme activity upon the redox state of ferredoxin and electron carriers; the redox state of the latter was estimated by analysis of the DCMU-induced relaxation kinetics of chlorophyll fluorescence quenching in the presence of different substrates.
相似文献147.
Intact chloroplasts prepared from summer-grown spinach plants supported (aspartate plus 2-oxoglutarate)-dependent O2 evolution but not (glutamine plus 2-oxoglutarate)-dependent O2 evolution. The former activity, which was sensitive to amino oxyacetate, was attributed to transaminase activity and reduction of the resulting oxalo-acetate to malate using H2O as eventual electron donor. A reconstituted chloroplast system which included chloroplast stroma, thylakoid membranes, ferredoxin and NADP(H) supported O2 evolution in the presence ofl-glutamine and 2-oxoglutarate at rates of 15–22 μmol mg-1 chlorophyll h-1 although lower rates were obtained with material from winter-grown plants. Activity was not observed in the absence of ferredoxin and omission of NADP(H) decreased activity by 40%. The reaction was associated with the production of 0.49 mol O2 mol-1 2-oxoglutarate consumed and up to 0.46 mol O2 mol-1 glutamine supplied. The reaction, which was inhibited by azaserine but not by methionine sulphoximine or amino oxyacetate, was attributed to light-coupled glutamate synthase (EC 1.4.1.13) with H2O serving as eventual electron donor. Activity was not affected significantly byl-malate. The reconstituted system also supported O2 evolution in the presence of nitrite, oxaloacetate, (aspartate plus 2-oxoglutarate) and oxidised glutathione. 相似文献
148.
Measurement of CO(2) and H(2)O Vapor Exchange in Spinach Leaf Discs : Effects of Orthophosphate 总被引:8,自引:8,他引:0 下载免费PDF全文
A leaf chamber has been designed which allows the measurement of both CO2 and water vapor exchange in Spinacia oleracea leaf discs. The center of the disc lies within a cylindrical gas chamber and its margins are enclosed within a cavity through which water or various metabolites can be pumped. In saturating light and normal atmospheres, the leaf discs have a relatively low resistance to H2O vapor transfer (rw = 1.87 seconds per centimeter) and can support high rates of photosynthesis for several hours. The abaxial surface of a disc had a higher resistance to water vapor transfer (rw = 3.22 seconds per centimeter) than the adaxial (rw = 2.45 seconds per centimeter) despite having a higher stomatal frequency (abaxial, 105/square millimeter; adaxial, 58/square millimeter). In 2% O2, the discs required an internal concentration of CO2 of 115 microliters per liter to support one-half of the maximal velocity of apparent photosynthesis (average value, 66 milligrams CO2 per square decimeter per hour). In 20% O2, the comparable values are 156 microliters per liter and 56 milligrams CO2 per square decimeter per hour. In air, apparent photosynthesis saturated at intensities (750 microeinsteins per square meter per second) well below that of daylight but, when the internal CO2 was raised to 700 to 900 microliters per liter, photosynthesis was not saturated even at daylight intensities (2025 microeinsteins per square meter per second). The distribution of Prussian blue crystals, formed after ferrocyanide feeding, showed that water entered the disc via the vasculature. When 25-minute pulses of orthophosphate were provided in the feeding solution, there were concentration-dependent increases in both rw and rm leading to inhibition of photosynthesis. The orthophosphate-dependent inhibitions were reversible. 相似文献
149.
The H-2
dm1
mutation and Qa antigens 总被引:2,自引:0,他引:2
P. Mark Hogarth Ian D. Walker Aveline J. Rigby Ian F. C. McKenzie 《Immunogenetics》1983,18(6):617-624
The effect of the H-2dm1 mutation on Qa-m2 expression was examined. The mutant strain B10.D2-H-2dm1 showed a fourfold increase in Qa-m2 expression when compared with the parental strain B10.D2. Qa-m2 molecules immunoprecipitated from B10.D2-H-2dm1, C57BL/10, and B10.D2 spleen cells were identical by two-dimensional (2-D) gel electrophoresis [isoelectric focusing (IEF) followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE]). It is likely therefore that the increased Qa-m2 expression is not due to gross structural alterations of the Qa-m2 molecule; in the present study, alternative explanations are discussed. 相似文献
150.
The ultrastructure of the pituitary, the adrenal, and the lung was examined in the newborn wallaby, Macropus rufogriseus. Tissue from six wallaby neonates (less than 8 hr of age), two near-term fetuses (26 days after removal of suckling pouch young [RPY]), and a two-day-old pouch young was examined; and tissue levels of cortisol in the adrenal glands of five neonates and a near-term fetus (26 days) were measured by radioimmunoassay. At birth the adenohypophysis comprised the bulk of the pituitary gland. The pars distalis was well vascularized and many cells contained electron-dense, membrane-bound granules. The adrenal glands lacked specific zones but comprised two distinct populations of cells. The cytoplasm of one cell type contained electron-dense, membrane-bound granules, similar to those observed inside catecholamine-secreting cells of the adrenal medulla; the other cell type possessed large amounts of smooth endoplasmic reticulum and mitochondria with tubulo-vesicular cristae. These features are characteristic of cells which are actively synthesizing steroid hormones. The concentration of cortisol was 0.58 ng/adrenal in the wallaby at birth. The fetal lungs near term were at the glandular stage of development, and epithelial differentiation of type I and type II pneumocytes was imminent although attenuation was not evident. The canalicular neonatal lung did not contain true alveoli, but type II pneumocytes contained osmiophilic lamellar inclusions of surfactant. The fetal pituitary and adrenal are functional at birth and are thus capable of initiating parturition and of influencing lung maturation in the fetus. 相似文献