Scanning electron microscopical observations on the shedding of the tegument of adult Schistosoma mattheei

In search of indications of membrane turnover the teguments of male Schistosoma mattheei from cattle and laboratory rodents were studied by means of scanning electron microscopy. A number of slightly elevated circular patches of tegument which appeared to peel off on the edges were seen on the outer membrane of a limited number of specimens from both rodents and cattle. It is suggested that this phenomenon may represent limited rapid turnover of the outer layer in response to host immunological action.     

Fructose 2,6-bisphosphate as a contaminant of commercially obtained fructose 6-phosphate: Effect on PPi:fructose 6-phosphate phosphotransferase

Fructose 6-phosphate from several commercial sources was shown to be contaminated with fructose 2,6-bisphosphate. This contaminant was identified by its activation of PP_i:fructose 6-phosphate phosphotransferase, extreme acid lability and behaviour on ion-exchange chromatography. The apparent kinetic properties of PP_i:fructose 6-phosphate phosphotransferase from castor bean endosperm were considerably altered when contaminated fructose 6-phosphate was used as a substrate. Varying levels of fructose 2,6-bisphosphate in the substrate may account for differences that have been observed in the properties of the above enzyme from several plant sources.     

Pollen Wall Ontogeny of Felicia muricata (Asteraceae: Astereae)

Pollen wall development in Felicia muricata Thunb. Nees (Asteraceae)was investigated by electron microscopy after addition of thelypophilic dye malachite green to the primary fixative. Pollenwall formation commences with the deposition of fibrillar electrondense units which represent future interbacular spaces. Radiallyarranged trilammelate structures develop between the fibrillarunits. Sporopollenin is deposited in the trilammelate structures.After release of the microspores from the tetrad, formationof interbacular spaces is accompanied by disintegration of fibrillarunits. Endexine formation occurs on white lines of unit membranedimensions. Intine formation follows the pattern described formost angiosperms. Observation of bead-like globules and pollenkittwith a membraneous structure is presumed to be related to theaddition of malachite green to the fixative.Copyright 1993,1999 Academic Press Felicia muricata (Thunb.) Nees, pollen, pollenkitt, ultrastructure, fixation     

Pflanzensoziologische Studie der Fynbosvegetation am Kap der guten Hoffnung

Zusammenfassung Im Swartboschkloof-Naturschutzgebiet am Kap der Guten Hoffnung wurden pflanzensoziologische Methoden ausprobiert und ergaben eine vorl?ufige Klassifikation der dortigen Fynbos-(Macchia), Flu?saum- und Wald vegetation. Acht Gesellschaften sind floristisch beschrieben und mit Standortfaktoren korreliert worden. Die Ergebnisse sind vielversprechend, und die M?glichkeiten einer Klassifikation der kapl?ndischen Fynbos-Vegetation in ein formelles pflanzensoziologisches System werden diskutiert.

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Summary TheBraun-Blanquet phytosociological method was tested in the complex Fynbos (Macchia) vegetation of the Cape of Good Hope, South Africa. In Swartboschkloof Nature Reserve the Fynbos, riverine scrub and forest vegetation was classified preliminarily into eight communities, which are described floristically and related to habitat. The results hold promise, and the possibilities of classifying the Cape Fynbos in a formal phytosociological system are discussed.

     

Histology of ovaries of female rabbits immunized with deglycosylated zona pellucida macromolecules of pigs.

Female rabbits (n = 36, 6 per group) were immunized with: (i) solubilized isolated porcine zona pellucida (SIZP), which contains ZP1, 82 kDa; ZP3 alpha, 55 kDa; and ZP3 beta, 55 kDa; (ii) a purified preparation of ZP3 alpha and ZP3 beta (ZP3); (iii) purified endo-beta-galactosidase digested glycoproteins ZP3 alpha-(EBGD) and (iv) ZP3 beta-(EBGD) (each about 30% deglycosylated); (v) chemically deglycosylated core proteins ZP3 alpha-(DG) and (vi) ZP3 beta-DG (each greater than 92% deglycosylated). Rabbits injected with saline (n = 6) or Freund's adjuvant (n = 6) served as controls. Rabbits were bled weekly to monitor titres. Every six weeks two animals from each group (n = 16) were selected for unilateral oophorectomy followed by histological examination. Sections were scored for numbers of primary, secondary and tertiary follicles. Anti-ZP3 titres developed in all treatment groups and correlated with carbohydrate content (peak per cent [125I]-labelled ZP3 binding by radioimmunoassay: SIZP 71.9 +/- 1.2, ZP3 70.0 +/- 2.5, ZP3 alpha-EBGD 60.9 +/- 5.3, ZP3 beta-EBGD 56.4 +/- 5.0, ZP3 alpha-DG 56.4 +/- 4.0, ZP3 beta-DG 53.5 +/- 4.3) (means +/- SEM). Animals immunized with SIZP, ZP3 and ZP3 beta-EBGD showed a statistically significant reduction in the number of primary, secondary and tertiary follicles compared with controls (P less than 0.01, MANOVA), whereas animals immunized with ZP3 alpha-EBGD, ZP3 alpha-DG and ZP3 beta-DG did not (P greater than 0.05, MANOVA). These results demonstrate that immunization with purified ZP3 alpha macromolecules (ZP3 alpha-EBGD, ZP3 alpha-DG) or ZP3 beta-DG does not produce histopathological changes in ovaries. Such deglycosylated ZP macromolecules represent potential target antigens for immunocontraceptive development.     

Scanning electron microscope studies of miracidia suggest introgressive hybridization between Schistosoma haematobium and S. haematobium x S. mattheei in the Eastern Transvaal

Schistosoma haematobium miracidia were collected from a locality with a high prevalence of human infection with the animal parasite, S. mattheei, which hybridizes with S. haematobium, and from 2 localities with negligible infection rates. The terebratoria of the miracidia from these localities were compared with each other, with laboratory maintained S. haematobium and with four populations of S. mattheei by means of scanning electron microscopy. It was found that the terebratorial membrane of certain of the S. haematobium miracidia from the locality with a high S. mattheei prevalence in humans, resembled the more intricate membrane of S. mattheei. This suggests introgressive hybridization between S. haematobium and S. haematobium x S. mattheei.