摘要:

ABSTRACTThe leechCalliobdella vivida(Verrill) is the vector ofTrypanoplasma bullocki.At 10°C, infective‐stage flagellates were first present in the leech's proboscis sheath five days after feeding. At 5°C, infective‐stage flagellates were not present in the leech's proboscis sheath until 10 days after feeding, but at 20°C, flagellates were located there as early as 24 h after feeding. Infected leeches retained flagellates through three subsequent feeds on uninfected fish. When flagellates were first observed in hogchoker,Trinectes maculatus(Bloch&Schneider), they were much larger than infective stages from the leech. Average flagellate length then decreased during early acute phase, but gradually increased thereafter. Peak parasitemia was greater in a hogchoker inoculated by only one leech but held at colder temperature than in a hogchoker inoculated by 45 leeches, suggesting that temperature may be more important than inoculum in determining peak parasitemia. Cell division in the fish host is described. SEM studies of fish blood flagellates revealed a pre‐oral ridge and a c

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02882.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTPlasmodium bergheiinfection was more severe in pregnant than in nonpregnant mice. Infection initiated on gestation day 7 resulted in rapidly increasing parasitemia and deaths of all pregnant mice within 12 days, while some nonpregnant mice survived until day 21 postinfection. When mice were infected on gestation day 12 or 14, a proportion of mice died before parturition; but some animals survived to deliver living pups. Reduced birthweights and increased spleen weight to body weight ratios were seen in pups from infected mice as compared with pups from uninfected animals. Histopathological abnormalities of placentae from infected animals included degeneration of the normal labyrinthine architecture and thickening of the trophobast separating maternal and fetal blood vessels.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02883.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTA recent isolate ofEimeria praecox, strain G, was obtained from Georgia and purified. Studies of the life history, pathogenicity, and cross‐immunity of the isolate were conducted to verify its identity. In inoculated three‐week‐old chickens, the occurrence of merogony and gametogony was limited to the superficial epithelium of the upper intestine. Oocysts, 23 × 19.5 äm, with a shape index of 1.17 were first observed 83 h after inoculation. Mortality and morbidity were not observed in any of the experimental birds. However, there was a positive correlation between dose of oocysts, reduced weight gain, and the incidence of exudative diathesis. These studies showed thatE. praecoxdepresses weight gains in chickens and may be of economic importance. Although complete immunity to avian coccidiosis is believed to be species specific, chickens immune toE. praecox(G) orE. acervulinahad a degree of cross‐immunity to a heterologous challenge. Electrophoretic analysis of glucose phosphate isomerase and lactate dehydrogenase prepared from the European strain ofE. praecoxandE. praecox(G) showed no differences, confirming the identity of the isolate asE

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02884.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTA system of prescreens and screen has been developed to select chelators as potential drugs againstTrypanosoma brucei bruceiEATRO 110. The chelators tested were nearly all commercially available, low molecular, and having moderate to high affinity for Fe(III). We prescreened 70 compounds showing heme‐sparing or inhibitory activity in aCrithidia fasciculatagrowth system having excess Fe and minimal hemin. Of these, 45 were highly trypanocidal for suspensions of bloodstreamT. b. brucei; criteria of activity here were immobilization, lysis, and loss of infectivity. Eighteen of the chelators highly active in the suspension prescreen were tried inT. b. brucei‐infected mice. Thirteen of these chelators were curative in mice with 24‐h infections, that is, they allowed survival>30 days beyond the untreated controls. 3,4‐Dihydroxycinnamic acid (caffeic acid). 2,9‐dimethyl‐1, 10 phenanthroline (neocuproine), and 2‐pyridinecarboxaldehyde‐2‐pyridyl‐hydrazone cured five out of five mice after an i.v. dose of 100 mg/kg. Salicylaldehyde thiosemicarbazone cured five out of five mice at an i.p. dose of 500 mg/kg. Lesser activity was shown by seve

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02885.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTTetrahymena pyriformisstrain WH‐14 secreted large quantities of intracellular proteases into its culture medium during growth. Extracellular enzymes were purified to homogeneity from cell‐free medium by ammonium sulfate precipitation, CM‐Sephadex column chromatography, gel filtration, and DEAE‐cellulose column chromatography. The DEAE‐cellulose eluates were separated into four peaks (P‐I, P‐II, P‐III, and P‐IV), each of which exhibited a different specific activity toward azocasein and α‐N‐benzoyl‐DL‐arginine‐ρ‐nitroanilide (Bz‐Arg‐Nan). These four forms of the protease showed similarity in amino acid composition, molecular weight (21,000–24,000), and antigenic reactivity. They had pH optima at neutral range. P‐I showed the highest specificity to azocasein whereas P‐IV was most effective toward the synthetic substrates. The Km values for hydrolysis of Bz‐Arg‐Nan were 2.4, 1.6, 1.3, and 1.4 mM for P‐I, P‐II. P‐III, and P‐IV, respectively, and the corresponding Kcat/Km values were 5.0, 9.4, 28.5, and 114.3 S‐1.M‐1. These properties of secreted proteases were compared with those of intracellular proteases purified by the same procedure except for the initial Triton X‐100 extraction. There were similarities in specific activity toward two substrates, molecular weight, Km, pH optima, and antigenic reactivity between the proteases from two sources, providing evidence that the intracellular proteases may be

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02886.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTHistones were prepared from chromatin of the eukaryotic (endosymbiont) nucleus ofPeridinium balticum(Levander) Lemmermann. The amino acid composition of whole histone was rich in lysine and similar to that ofOlisthodiscus luteusandEuglena gracilis. Electropheretic analysis of these proteins in acidic‐urea disc gels revealed four major bands: one with a mobility slightly lower than that of calf thymus HI; and three others which comigrated with calf H2B, H2A, and H4, respectively. The low mobility band was soluble in 5% perchloric acid and was sensitive to FeCl3destaining. Electrophoresis in slab gels containing 0.1% SDS revealed five major components, with approximate molecular weights of 23,000, 20,000, 15,000, 13,000, and 11,000, respectively. The 15,000 and 11,000 dalton histones had mobilities identical to those of calf H3 and H4, respectively. The two highest molecular weight components were soluble in 5% perchloric acid. No bands were found to comigrate with calf H2A or H2B but a band was present that migrated to a position intermediate between calf H2A and H4 (13,000 dalton histone). Two‐dimensional gels consisting of acidic‐urea gels in the first dimension and SDS gels in the second dimension revealed that the 20,000 dalton component and the 13,000 dalton component are not resolved in the acidic‐urea gel. As a working hypothesis, it is suggested that two of the five bands seen in SDS gels represent an H1‐like doublet, and two are analagous to H3 and H4, respectively. The remaining histone may replace H2

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02887.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe antiviral agent phosphonoacetic acid inhibits growth ofTetrahymena thermophilaat concentrations comparable to those inhibiting growth of other eukaryotic cells, with 50% inhibition at 0.5 mM phosphonoacetic acid. The compound is cytotoxk toTetrahymenaat concentrations greater than 2.0 mM. When a culture ofTetrahymenathe growth of which was totally inhibited by 2.0 mM phosphonoacetic acid was diluted with fresh medium, growth resumed in an exponential, rather than synchronous, fashion. [2–14C]phosphonoacetic acid is not metabolized byTetrahymen

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02888.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe size and fatty acid composition ofTetrahymena pyriformisW cells were influenced by the provision of a nutritional supplement of ergosterol, cholesterol, or tetrahymanol, but not of 20‐isocholesterol. Ergosterol and cholesterol addition led to a reduction in cellular volume, an increase in glycerophospholipid saturated fatty acid content, and an increase in palmitoleic acid and its metabolic products when compared to unsupplemented controls. Tetrahymanol supplementation resulted in an increase in cellular volume, a decrease in saturated fatty acid content, and a reduction in palmitoleic acid and derivatives. 20‐Isocholesterol was accumulated by the cells; however, this compound had no effect on any of the parameters followed in this investigation and had only a small depressant effect on tetrahymanol biosynthesis. Ergosterol and cholesterol had the same impact on the ciliates, even though the ergosterol‐supplemented cells contained approximately three times as much free sterol as did cholesterol‐grown cells. The amount of the free cholesterol and metabolic products in supplemented cultures was similar to the amount of tetrahymanol present in control cultures. This observation suggests that the cells recognize qualitative differences among the various polycyclic alcohols rather than responding to the amount of sterol present. Increased cellular levels of tetrahymanol led to a response unlike that of the true sterols, which again suggests that the high degree of specificity depends on the structure of the added polycyclic alcohol. The changes in fatty acid composition may be required to maintain proper interaction of the polar lipids and the polycyclic alcohols to give an appropriate degree of membrane f

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02889.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe separation of extracellular protozoan parasites from host cells based on a difference in surface charge has been described. However, withTrypanosoma cruzino method exists for the isolation of pure parasite stages from heterogeneous mixtures. Studies on the electrophoresis of mixed stage populations confirm significant surface charge density differences exist among epimastigotes, trypomastigotes, and amastigotes. In ascending order of electronegativity, amastigotes have the lowest charge density, try‐pomastigotes next, followed by epimastigotes. A technique has been developed for the separation of purified populations of parasites based on these charge differences using a continuous free‐flow electrophoresis apparatus. The separated populations are morphologically intact and maintain their infectivity to mice. This separation method is applicable for preparative and analytical isolation of pure stages ofT. cruzifor biochemical and immunological stud

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02890.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe iodinating reagent 1,3,4,6,‐tetrachloro‐3α,6α‐diphenylglycoluril (IODOGEN3) was used to label antigens on zygotes ofPlasmodium gallinaceumwith parallel studies using lactoperoxidase‐catalyzed radioiodination for comparison. Proteins labeled by the IODOGEN method are most probably on the surface of the zygote, as the pattern of labeled proteins analyzed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis was very similar to the pattern of lactoperoxidase‐labeled proteins. Furthermore, the labeled proteins represented only a subset of the total Coomassie Blue‐stained proteins. The radioiodinated zygote proteins were immuno‐reactive after IODOGEN or lactoperoxidase labeling. The IODOGEN method is technically much more simple than the lactoperoxidase method and does not require the addition of extraneous proteins or H2O2. The advantages of IODOGEN labeling, together with the essential equivalence of results obtained by these two, methods, make the IODOGEN method attractive for labeling parasite an

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1982.tb02891.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY