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2.
One hundred twenty-three of 300 blood samples (41%) taken from Rio Grande wild turkeys (Meleagris gallopavo intermedia) from three locations in southern Texas (Welder Wildlife Refuge, Chaparrosa Ranch, and Campo Alegre Ranch) and subinoculated into domestic broad-breasted white turkey poults were positive for a Plasmodium (Novyella) sp. Analysis of blood films from 350 turkeys revealed Haemoproteus meleagridis in 76% of the birds. A significantly greater mean parasite intensity was observed in birds from Welder Wildlife Refuge. Birds from the Campo Alegre Ranch exhibited a significantly higher prevalence of H. meleagridis than birds from Chaparrosa. The Plasmodium sp. was infective for canaries (Serinus canaria), bobwhites (Colinus virginianus), and ring-necked pheasants (Phasianus colchicus), but would not produce infection in white leghorn chickens (Gallus gallus) or Coturnix quail (Coturnix coturnix). Attempts to infect Culex tarsalis and C. pipiens were unsuccessful. Asexual erythrocytic synchrony was not observed when blood-induced infections were monitored in two domestic turkey poults every 4 hr for 72 hr. Exoerythrocytic stages were not found upon examination of impression smears and tissue samples taken from brain, liver, spleen, kidney, lung, and bone marrow. The Plasmodium sp. is most similar morphologically to three species in the subgenus Novyella, P. hexamerium, P. vaughani, and P. kempi. The most striking similarities are to P. hexamerium, and involve mean merozoite number, erythrocytic schizont location, and vertebrate host susceptibility. It differs from P. vaughani in being able to infect turkeys and in type of parasitized erythrocytes. Differences to P. kempi include mean merozoite number, and ability to infect pheasants, and its inability to develop in C. pipiens and C. tarsalis. 相似文献
3.
R A Anderson I Correas C Mazzucco J D Castle V T Marchesi 《Journal of cellular biochemistry》1988,37(3):269-284
Analogues of the human erythroid membrane skeletal component protein 4.1 have been identified in perfused rat tissues and human T and B lymphocyte cell lines. olyclonal antibodies were used which are specific for all domains of protein 4.1, the spectrin-actin-promoting 8-Kd peptide, the membrane-binding 30-Kd domain, and the 50-Kd domain. Antibody reactivity, by Western blotting of tissue homogenates, shows reactivity with proteins varying in molecular weight from 175 Kd to 30 Kd. Further, these protein 4.1 analogues appear to be expressed in a tissue-specific fashion. Of the analogues detected there appear to be at least three classes: analogues containing all erythroid protein 4.1 domains, analogues containing all domains but with modified antigenic epitopes, and analogues containing only some domains. Chemical cleavage at cysteine linkages indicates that in analogues containing the 30-Kd region the location of cysteine is highly conserved. This datum suggests that in nonerythroid 4.1 isoforms of higher molecular weight the additional protein mass is added to the amino terminal end (30 Kd end). 相似文献
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5.
Crosses among Homokaryons from Commercial and Wild-Collected Strains of the Mushroom Agaricus brunnescens (= A. bisporus) 总被引:9,自引:5,他引:4 下载免费PDF全文
A new technique for the production of hybrid strains of the cultivated mushroom Agaricus brunnescens is described. Homokaryons were recovered from regenerated protoplasts obtained from several heterokaryotic strains. A total of 16 novel hybrids were produced in 63 attempted crosses between paired homokaryons. Recovery of both homokaryons and hybrids was verified by analysis of restriction fragment length polymorphisms. Three of four hybrids fruited in small-scale tests, further confirming that the isolates were true hybrids. Colony morphology alone was found to be a poor indicator of hybrid status. In two instances, three homokaryons crossed successfully in all combinations, suggesting that there are at least three alleles at the putative mating-type locus. Crosses between homokaryons from commercial and wild-collected isolates indicated that these strains belong to the same biological species. 相似文献
6.
Measurement of intracellular sodium concentration and sodium transport in Escherichia coli by 23Na nuclear magnetic resonance 总被引:6,自引:0,他引:6
Escherichia coli is known to actively extrude sodium ions, but little is known concerning the concentration gradient it can develop. We report here simultaneous measurements, by 23Na NMR, of intracellular and extracellular Na+ concentrations of E. coli cells before and after energization. 23Na spectra in the presence of a paramagnetic shift reagent (dysprosium tripolyphosphate) consisted of two resonances, an unshifted one corresponding to intracellular Na+ and a shifted one corresponding to Na+ in the extracellular medium, including the periplasm. Extracellular Na+ was found to be completely visible despite the presence of a broad component in its resonance; intracellular Na+ was only 45% visible. Measurements of Na+ were made under aerobic and glycolytic conditions. Na+ extrusion and maintenance of a stable low intracellular Na+ concentration were found to correlate with the development and maintenance of proton motive force, a result that is consistent with proton-driven Na+/H+ exchange as a means of Na+ transport. In both respiring and glycolyzing cells, at an extracellular Na+ concentration of 100 mM, the intracellular Na+ concentration observed (4 mM) corresponded to an inwardly directed Na+ gradient with a concentration ratio of about 25. The kinetics of Na+ transport suggest that rapid extrusion of Na+ against its electrochemical gradient may be regulated by proton motive force or intracellular pH. 相似文献
7.
8.
A FUSCA gene of Arabidopsis encodes a novel protein essential for plant development. 总被引:17,自引:8,他引:9 下载免费PDF全文
Arabidopsis fusca mutants display striking purple coloration due to anthocyanin accumulation in their cotyledons. We describe six recessive fusca mutants isolated from Agrobacterium-transformed Arabidopsis families. These mutants first become defective during embryogenesis and exhibit limited seedling development. Double mutant constructs revealed that developmental defects were not simply a consequence of anthocyanin accumulation. fusca seedlings showed altered responses to several environmental and endogenous factors. Allelism tests established that three fusca loci are represented by mutants previously described as defective in light-regulated responses. To study the molecular basis of the fusca phenotype, we cloned the FUS6 gene. FUS6 encodes a novel protein that is hydrophilic, alpha-helical, and contains potential protein kinase C phosphorylation sites. The FUSCA proteins appear to act in a network of signal transduction pathways critical for plant development. 相似文献
9.
K. T. Castle B. A. Wunder 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,164(8):609-617
We fed prairie voles (Microtus ochrogaster) rat chow diluted with variable amounts of -cellulose to determine 1) how much fiber the voles could tolerate in their diet; 2) changes in food intake and digestibility of dry matter and of fiber; 3) the extent to which voles utilized fiber as an energy source; and 4) whether any of these variables differed between groups of animals maintained at 5 or 22°C. Fiber content of the diets ranged from 20 to 84%. Animals held at 5°C maintained body mass through a diet containing 69% fiber, while animals held at 22°C maintained body mass through the 84% fiber diet. Dry matter intake increased with fiber level from 9.3 to 15.0 g·day-1 for animals at 5°C and from 5.6 to 14.0 g·day-1 for animals at 22°C; intake on the highest fiber diet eaten by either group was not different. Dry matter digestibility decreased significantly as the fiber in the diets increased, but was not affected by temperature treatments. Digestible dry matter intake for each group remained constant regardless of diet quality, but on each diet digestible dry matter intake for animals at 5°C was significantly higher than that of the animals held at 22°C. Digestibility of the fiber portion of the experimental diets remained constant as food quality decreased, so the percent of daily energy need met by fiber utilization increased with higher food intake. On the lowest quality diet each group tolerated, fiber digestion provided approximately 42 and 68% of the energy needs of voles at 5 and 22°C, respectively.Abbreviations BM
body mass
- BMR
basal metabolic rate
- DE
digestible energy
- DM
dry matter
- DMD
dry matter digestibility
- DDMI
digestible dry matter intake
- MR
metabolic rate
- NDF
neutral detergent fiber (=cell walls)
- NDS
neutral detergent solubles (=cell solubles)
- SEM
standard error of mean
-
T
a
ambient temperature 相似文献
10.
Fifty-nine gastrointestinal tracts and 52 blood samples were collected from eastern wild turkeys (Meleagris gallopavo silvestris Vieillot) during the spring turkey hunts of 1979-1980 from two areas in western Kentucky and Tennessee. Eight species of parasites were recovered, and included (combined prevalence): Haemoproteus meleagridis Levine, 1961 (25%), Hymenolepis carioca (Magalhaes, 1898) (44%), Metroliasthes lucida Ransom, 1900 (25%), Raillietina georgiensis (Reid and Nugara, 1961) (15%), R. williamsi Fuhrmann, 1932 (64%), Ascaridia dissimilis Perez Vigueras, 1931 (83%), Capillaria caudinflata (Molin, 1858) (2%), and Heterakis gallinarum (Schrank, 1788) (27%). A significant difference existed between the intensities of A. dissimilis from the two states. Twenty-two subinoculations of collected blood were made in 1979, but no Plasmodium infections were recovered. Helminths of wild turkeys from 11 southeastern states were compared using similarity and diversity indices. High similarities were observed in helminth populations of two groups of states: 1) Alabama, Mississippi, Arkansas, Virginia, and Tennessee; and 2) Tennessee, Kentucky, and Illinois. Simpson's diversity index indicated helminth populations of wild turkeys in Florida were the most diverse (0.10), while those in Louisiana turkeys were the least diverse (0.33). 相似文献