摘要:

The ultrastructural changes occurring during macrogametogony inEimeria brunettiwere studied in tissue from the small intestine of infected young domestic fowls. As the macrogametocyte developed, an increase in the volume of the cytoplasm and the nucleus occurred. At this early stage of development the organism was limited by a single unit membrane which possessed a number of micropores. The organism was situated in a parasitophorous vacuole which contained intra‐vacuolar folds and intra‐vacuolar tubules. The wall forming bodies of Type II (WFB II) started to appear before the wall forming bodies of Type I (WFB I). The WFB I developed in the cytoplasmic matrix whereas the WFB II were formed within the cisternae of the rough endoplasmic reticulum apparently in association with Golgi bodies. The mature WFB I were homogeneous, limited by a unit membrane, and larger than WFB II which had no limiting membrane but remained surrounded by a membrane of the rough endoplasmic reticulum. Polysaccharide granules were formed in the cytoplasm between strands of the rough endoplasmic reticulum. During maturation the WFB I&II and the polysaccharide granules increased in size and number, and as this occurred a number of electron translucent vacuoles were ejected from the surface of the macrogametocyte. The mature macrogamete possessed a large nucleus with a nucleolus, a number of multi‐membranous vacuoles, mitochondria, and canaliculi. The WFB I&II were located at the cell periphery and the polysaccharide granules further towards the interior of the organism. The organism was limited by a unit membrane but during macrogametogony a homogeneous layer had developed which extensively coated the macrogamete's surface. Below the limiting membrane two closely applied unit membranes had f

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1977.tb01677.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Enterotoxin fromClostridium perfringenstype A has been purified. The enterotoxin was shown to be heat‐labile, but re‐activation of heat treated enterotoxin did occur down to an activity of 15 per cent of the native enterotoxin. The molecular weight was shown to be 34,000 by ultracentrifugation, and the molecular weight did not change significantly after treatment with 0.1 M β‐mercaptoethanol and 6 M guanidine hydrochloride. It was concluded that the enterotoxin consists of one single polypeptide chain. The enterotoxin did not lose any activity after treatment with iodoacetic acid and iodoacetamide, but a complete loss of activity was observed after succiny

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1977.tb01678.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AvirulentToxoplasma gondiiwere made virulent by passages in mice, and then attenuated by storage. In contrast to the avirulent parasites, attenuated organisms did not appear to form cysts in mice and rabbits, although parasites could be isolated from such animals as long as three months after their inoculation. Rabbits infected with parasites of attenuated ‐ virulence had high antibody levels, and survived challenge with virulentToxoplasma gondii.Cysts were not detected in the brains of such rabbits following this second infection. By following the generation ofToxoplasma gondiiin mouse peritoneal cavities, it was found that attenuated parasites resembled avirulent more than virulent organisms. Although the effect of attenuation was mainly on the parental generation of parasites, some genetic effect seemed to be involved as wel

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1977.tb01679.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The application of the counter‐current immunoelectrophoresis (CIE) for determination ofE. coliacidic polysaccharide K antigen is described. The most appropriate dilutions of antigens and antisera were established after examination of six different K antigens with homologous OK antisera. According to this result all test strains for acidic polysaccharide K antigens,i.e.K1 to K57, K62, K74, K82, K83, K84, K92, K93, K94, K95, K96, K97, K98 and K100, were examined and OK antisera suitable for the CIE test were selected. The following reciprocal cross‐reactions were found: K2 and K62; K7 and K56; K12 and K82; K13, K20 and K23; K18 and K22; K16 and K97, and K53 and K93. The CIE method is now used as a routine test in our laborat

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1977.tb01680.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Two strains ofFrancisella tularensiswere grown on a selective chocolate agar, used for the isolation of gonococci. The growth conditions appeared to be satisfactory, and contaminating flora was largely eliminated, thus facilitating reisolation and diagnosis.

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1977.tb01681.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The ultrastructure of the late sporoblast and the initiation of sporozoite formation inE. brunettiwas examined in oocysts which had been allowed to sporulate for 24 hours at 27d̀ C. The late sporoblast was ellipsoidal in shape and possessed two nuclei, with associated Golgi bodies, situated at either end of the organism. Its cytoplasm contained numerous polysaccharide granules, electron translucent vacuoles, dense bodies, mitochondria, and some strands of rough endoplasmic reticulum. The sporoblast, at this stage, was enclosed by two unit membranes. Sporozoite formation was initiated by the appearance of a dense plaque at either end of the organism in the vicinity of a nucleus, adjacent to the limiting membrane of the sporoblast. A conoid was present in the central region of the plaques. Sporozoite formation was similar to the initiation of merozoite formation in the schizont. Endodyogeny did not appear to be involved in the process of sporozoite formation

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1977.tb01682.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY