Cloning of Eimeria tenella in the chicken.
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Animals↗
Biomedical subjects
M E Rose
Publications and source records attributed to M E Rose.
Eimeria vermiformis: host strains and the developmental cycle.
After confirmatory studies of the endogenous development of Eimeria vermiformis in hybrid mice, a comparison, both qualitative and quantitative, was made of the developmental cycle of the parasite in two strains of host of contrasting susceptibility. No differences were apparent between the resistant, BALB/c, and susceptible, C57BL/6, during the first 5 days of the cycle. Thereafter, more parasites were seen in the C57BL/6, they were more widely distributed along the intestine, and they persisted in the tissues for a considerably greater time. Schizogony continued for longer in the C57BL/6 mice, concurrently with gametogony, and there were probably up to four additional generations of schizonts, which resembled those of the accepted third generation. The kinetics of oocyst production, measured in the feces, reflected events in the intestinal epithelium. The findings are discussed in relation to eimerian life cycles and the immune response.
Animals↗
Metabolism of testosterone by human semen.
Following the incubation of human sperm and seminal plasma with 13C2-labelled testosterone, the main metabolite, identified by gas chromatography-mass spectrometry (GC-MS), was 4-androstene-3,17-dione. In addition, 6 alpha- and 6 beta-hydroxytestosterone were identified. The more common metabolites of testosterone were not detected, and it is possible that the high substrate-tissue ratio influenced the result. Incubation of individual sperm and seminal plasma specimens with [14C]testosterone resulted in the identification, by specific activity measurements, of 4-androstene-3,17-dione in almost every specimen but with a widely varying conversion rate. Dihydrotestosterone, which on general grounds was considered a likely metabolite, could not be positively confirmed as such, although in some samples its presence was suspected. Gas chromatography-mass spectrometry was also used to identify steroids in sperm and seminal plasma extracts. Some, but not all the steroids identified as present in such extracts by other investigators, were found. During the course of this work C18 Sep-Pak cartridges were successfully used to prepare fractions suitable for SP-Sephadex and TEAP-Lipidex chromatography and subsequent analysis by GC-MS. Their use eliminated the need for purification steps otherwise necessary.
Androstenedione↗
Host specificity in eimerian coccidia: development of Eimeria vermiformis of the mouse, Mus musculus, in Rattus norvegicus.
The ability of Eimeria vermiformis, a coccidium which normally parasitizes the mouse, to develop in rats was investigated. The Rowett strain (Lac: RNU) rats were euthymic (rnu/+), treated or untreated with cortisone acetate, and athymic (rnu/rnu). E. vermiformis completed its development only in rnu/rnu rats, which passed small numbers of oocysts capable of sporulating and infecting C57BL/6 mice. In the rnu/+ rats, irrespective of cortisone treatment, development appeared to terminate with the completion of the asexual (schizogonic) stages since no gametocytes were recognized in the tissues and no oocysts were detected in the faeces. The findings are discussed with reference to the factors which govern host specificity.
Animals↗
Systemic release of mucosal mast cell protease during infection with the intestinal protozoal parasite, Eimeria nieschulzi. Studies in normal and nude rats.
The systemic secretion of rat mucosal mast cell protease (RMCPII), a major product of rat mucosal mast cells (MMC), was examined during primary infections with the protozoan parasite, Eimeria nieschulzi in CFH/B, athymic (rnu/rnu) and euthymic (rnu/+) rats. Release of RMCPII into the blood stream (2.9 micrograms/ml of serum) of normal rats occurred within 1 day after infection. This response developed 3-6 hours after inoculation with oocysts, was dose-dependent, and was found in both naive and immune rats. Maximal release of RMCPII (4.5 micrograms/ml of serum) in naive rats occurs 9 days after primary infection, whereas the numbers of MMC and concentrations of mucosal RMCPII were maximal 14 days after infection, by which time the systemic RMCPII response had begun to decline. The numbers of MMC and concentrations of mucosal RMCPII in uninfected nude rats were similar to those in the heterozygous (rnu/+) litter-mates. After infection, the numbers of MMC and concentrations of mucosal RMCPII increased in the heterozygotes but not in nude rats. Similarly, RMCPII was detected systemically only in the heterozygotes.
Animals↗
Susceptibility to coccidiosis: contrasting course of primary infections with Eimeria vermiformis in BALB/c and C57/BL/6 mice is based on immune responses.
The effects of three immunosuppressive treatments--whole body irradiation and injections of cortisone acetate or cyclophosphamide, on the course of primary infections with Eimeria vermiformis were investigated in 'resistant' BALB/c and 'susceptible' C57BL/6 mice. Immunosuppression (and the nude athymic mutation in BALB/c mice) resulted in increased reproduction of the parasite in both strains of mice, indicating some immunological control of primary infections. The effect was, however, very much more marked in the BALB/c mice, resulting in an alteration in the relative susceptibilities of the two strains. The findings are discussed and it is suggested that the basis for the differences observed in the course of infection in normal BALB/c and C57BL/6 mice lies in their immune responses to this parasite.
Animals↗
Analysis of dipeptides in urine by gas chromatography/mass spectrometry: implications for collagen breakdown in iminodipeptiduria following a study of the dipeptides by electron impact and chemical ionization.
Dipeptides in the urine of a patient suffering from dermatological purpura, associated with iminodipeptiduria , were determined by gas chromatography/mass spectrometry. The dipeptides were identified as R-proline and R'-hydroxyproline where R is any one of the residues, glycyl, alanyl, valyl, leucyl, isoleucyl, seryl, aspartyl, glutamyl, prolyl, phenylalanyl and R' is alanyl, valyl, leucyl or isoleucyl, seryl, prolyl, glutamyl, phenylalanyl. The predominance of proline- and hydroxyproline-containing dipeptides and the percentage distributions of the other amino acid residues, R and R', strongly implicate an abnormality of collagen metabolism. Structural assignments are confidently based on (a) gas chromatographic retention times, (b) electron impact mass spectra and automatic comparison with reference to spectra stored in a specialized library, (c) chemical ionization mass spectra with isobutane and methanol as reactant gases and (d) the use of deuteriated acetic anhydride as a derivatizing agent.
Adult↗
Susceptibility to coccidiosis: effect of strain of mouse on reproduction of Eimeria vermiformis.
The reproduction of Eimeria vermiformis in different strains of phenotypically normal mice and in mice with various immunological characteristics or defects was compared. In some strains of phenotypically normal mice there were marked differences in oocyst production, both in terms of numbers and in the duration of patency, allowing the strains to be classified as resistant or susceptible to infection with E. vermiformis. These differences were apparent only in primary infections; both types of strain were equally resistant to reinfection. Amongst the strains of mice with immunological deficiencies, reproduction of the parasite was greatest in the athymic (nu/nu) mutants and these mice were completely susceptible to reinfection. Strains of mice with lowered or defective antibody production, or with defective neutrophils and low NK cell activity (bg/bg) were more susceptible than the relevant controls to primary infection but all developed substantial immunity to reinfection. Asplenic (Dh/+) mutants were remarkably resistant to infection.
Animals↗
The effect of immunity on the early events in the life-cycle of Eimeria tenella in the caecal mucosa of the chicken.
A comparison was made between the early events (asexual stages) in the life-cycle of Eimeria tenella in specifically immunized and control chickens. Particular attention was paid to the quantitative aspects and to the transport of sporozoites within intra-epithelial lymphocytes (IEL) from the enterocytes of the surface epithelium to the enterocytes of the crypts. There was a moderate decrease in the number of parasites initially seen in the mucosa of the immune birds, suggesting that some of the effects of immunity are exerted before penetration of the surface enterocytes, but the reduction in the numbers of developing parasites was more marked. This latter effect was due, at least partly, to failure of transfer of sporozoites from IELs to crypt enterocytes. These findings are discussed in relation to the efficacy of the immunity induced.
Animals↗
The large-scale preparation of purified sporozoites of Eimeria spp. by metrizamide density-gradient centrifugation.
A method is described for the reproducible purification of greater than 1.0 X 10(8) sporozoites of Eimeria spp. by centrifugation on metrizamide density-gradients. The mean contamination of the purified sporozoite fraction by sporocysts and sporocyst debris was less than 6% and the recovered sporozoites were fully viable, infective and ultrastructurally intact.
Centrifugation, Density Gradient↗
Coccidiosis: characterization of antibody responses to infection with Eimeria nieschulzi.
The antibody responses of rats to infection with the intestinal intracellular protozoan parasite Eimeria nieschulzi were examined by a sensitive radio-immunoassay with a soluble preparation of sporulated oocysts as antigen. Specific antibodies of the IgM, IgG1, IgG2a and IgG2b isotypes were found in the blood circulation and IgA antibodies were detected in the bile and in intestinal washings. The IgM response was rapid, its peak was relatively brief and it was not recalled by the reinoculation of oocysts. There were some differences between the responses in the different subclasses of IgG but they all reached a peak between 20-30 days after the initiation of the primary infection and there was an anamnestic response to a challenge inoculation of oocysts. IgA antibodies to E. nieschulzi antigen in the bile and in intestinal washings increased and decreased after both primary and secondary inocula. Antibodies of all isotypes tested were virtually absent in the blood circulation of infected athymic rats. These findings are discussed with reference to antibody responses to other parasitic infections and to the role of antibodies in immunity to coccidiosis.
Animals↗
Infection with Eimeria tenella: modulation of lymphocyte blastogenesis by specific antigen, and evidence for immunodepression.
The blastogenic effects of specific parasite antigen and of mitogens on the lymphocytes of chickens infected with Eimeria tenella were examined. Lymphocytes from infected chickens were stimulated to divide when cultured with parasite antigen, but their responses to the T-cell mitogen, phytohemagglutinin (PHA), were depressed throughout the period of infection. Responses to the B-cell mitogen, lipopolysaccharide (LPS), were depressed during the first week of infection but enhanced in the second week. The inclusion of plasma samples from infected chickens in the culture medium depressed the responses of normal spleen lymphocytes to PHA, suggesting that soluble suppressor factors are generated during infection.
Animals↗
Coccidiosis: rapid depletion of circulating lymphocytes after challenge of immune chickens with parasite antigens.
Characteristic changes in the numbers of peripheral blood leukocytes occurred after specific challenge of chickens immunized by infection with the intracellular intestinal coccidian parasite Eimeria maxima. Within minutes of enteric or intravenous challenge with viable parasites or with soluble parasite antigen, the numbers of circulating lymphocytes and, to a lesser extent, of heterophils were reduced. This was followed by a period of leukocytosis, the main cellular constituents of which were heterophils and lymphocytes. Indirect fluorescent staining with antisera to T- or B-lymphocytes showed the depletion in lymphocytes to be accounted for mainly by a reduction in the number of T-cells. The leukopenia after oral challenge, found in immunized birds, could be transferred to normal birds by the intravenous injection of serum, plasma, extracts of leukocytes, or suspensions of viable spleen cells.
Animals↗
Identification of the 22-phosphate esters of ecdysone, 2-deoxyecdysone, 20-hydroxyecdysone and 2-deoxy-20-hydroxyecdysone from newly laid eggs of the desert locust, Schistocerca gregaria.
The four major ecdysteroid (insect moulting hormone) conjugates present in the newly laid eggs of the desert locust, Schistocera gregaria, have been purified by reversed-phase and anion-exchange high-performance liquid chromatography. The steroid moieties were identified as ecdysone, 2-deoxyecdysone, 20-hydroxyecdysone and 2-deoxy-20-hydroxyecdysone. Phosphate analysis of acid-hydrolysed samples showed a steroid:phosphate ratio of approx. 1:1 for all four compounds. The intact conjugates were identified as ecdysone 22-phosphate, 2-deoxyecdysone 22-phosphate, 20-hydroxyecdysone 22-phosphate and 2-deoxy-20-hydroxyecdysone 22-phosphate by fast atom bombardment mass spectrometry and 1H, 13C and 31P n.m.r. The significance of ecdysteroid phosphates as a source of free hormone during embryogenesis is discussed.
Animals↗
A functional homologue of mammalian secretory component exists in chickens.
The existence of a molecule in chickens homologous to the secretory component of mammals has long been in dispute. An intravenous injection of [14C]fucose was given to chickens as a marker for newly synthesized glycoproteins and then unlabeled human IgA was injected intravenously half an hour later. It was shown that the human IgA subsequently appeared in the bile of the chickens combined with a [14C]fucose-labeled molecule; the chicken IgA in these bile samples was similarly labeled. Radiolabeled human secretory IgA was not transported in large amounts across the chicken liver in vivo and neither was purified chicken bile IgA. These results indicate that a molecule exists in chickens which behaves in a manner analogous to mammalian secretory component.
Animals↗
Ecdysteroids in adults of the nematode, Dirofilaria immitis.
Adult males and females of the dog heartworm, Dirofilaria immitis, were extracted separately and, following separation of the free and conjugated ecdysteroid fractions, the conjugates were hydrolysed enzymically. Both the ecdysteroids released by hydrolysis of the conjugates and the free hormones were further purified and analysed by a combination of radioimmunoassay, thin-layer chromatography and high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by gas-liquid chromatography/mass spectrometry (selected ion monitoring). Both males and females contained free and conjugated ecdysteroids. Evidence was obtained for the presence of ecdysone, 20-hydroxyecdysone, 20,26-dihydroxyecdysone and possibly ponasterone A. The possible parallel between ecdysteroid endocrinology in nematodes and insects is discussed.
Animals↗
Invasion of chicken caecal and intestinal lamina propria by crypt epithelial cells infected with coccidia.
The development of second generation schizonts of Eimeria necatrix and E. tenella was studied with the electron microscope. Invasion of the crypt epithelial cells by merozoites of the first generation schizonts caused changes in the morphology of the infected cells and stimulated their migration into the lamina propria through breaks which appeared in the basement membrane of the crypts. Second generation schizonts developed in the lamina propria within these crypt cells whose epithelial origin was confirmed by their interconnection by desmosomes and tight junctions and by their possession of characteristic microvilli. A comparison is made between this invasion of the lamina propria by parasitized cells and invasion of connective tissue by malignant epithelial cells; the possible mechanisms involved are discussed.
Animals↗