Isolation and characterisation of Plasmodium falciparum (Welch, 1897) soluble antigens from infected patient plasma, Western blotting, thermal stability and ELISA assays using hyperimmune IgG-antimalaria antibodies was the main objective of this work. A circulating antigen of approximately Mr 33-35 kDa with good specificity and antigenicity, in the plasma of malarial patients was shown. Heating at 100°C did not destroy its antigenicity. When fractions highly enriched in the 33-35 kDa proteins were used in ELISAs, a seroreactivity in plasma obtained from primary-infected individuals was found. Controls from normal patients were always negative. The antigenic characteristics suggest that it may be included within the group of new described Plasmodium soluble antigens.
Numerous coccidian stages were found in the kidney tubules of the golden carp (Carassius auratus gibelio). The merogonial and gamogonial stages were localized extracytoplasmally in the microvillous region of the epithelial cells. The host-parasite interface consisted of i) a large area where the parasite was separated from the host cytoplasm by the parasitophorous vacuole membrane only, and ii) a zone of multiple fusions of the host cell membrane investing the parasite to the neighbouring microvilli. The taxonomic status of the extracytoplasmic stages is not clear, however, their possible appurtenance to Eimeria scardimi, which was frequently found in the kidneys of golden carps in the same population, is discussed.
The macrophage cell-line J774.E1 and Leishmania m. mexicana infection was used to investigate the uptake of liposomes, which differed in their bulk phospholipid: ester- or ether-analogue of phosphatydilcholine (PC). The receptor-mediated uptake of both species of liposomes, containing native or acetylated LDL as ligands was also evaluated. Uninfected and infected J774.E1 cell-line accumulated more ester- and ether-liposomes alone than mixed type (50:50, ester/ether). The utilization was significantly enhanced when both types of liposomes contained native LDL. The highest uptake was recorded for liposomes bearing acetylated LDL by infected J774.E1 cells. Accumulation of ester- and ether-liposomes with the same ligand was not markedly affected by different chemical nature of PC. Finally, ether-liposomes alone possessed certain activity against Leishmania m. mexicana amastigotes. The results presented here demonstrated the usefulness of ether-liposomes with specific ligands in site-specific delivery of antileishmanial compounds in vitro.
A differential mechanical technique for tissue separation, based on the different physical resistance to grinding between mesophyll (M) and bundle sheath (BS) cells, was tested on dicotyledonous C4 plants A triplex canscens, A triplex halimus, Gomphrena globosa, Amaranthus retroflexus, Amaranthus caudatus and Portulaca oleracea. A metal sieve (35 mesh) was placed inside a mortar and pieces of leaves (0.5 cm2) were ground in an aqueous medium on the sieve to obtain a homogenate. The homogenate was at first collected below the sieve and was then filtered through six layers of muslin. Microscopic examination showed that the filtrate was enriched by the M cells and the residue was enriched by BS cells, few of which were broken. The BS cell fraction was then vigorously ground and filtered; this second filtrate was named the BS cell fraction and the first filtrate was named the M cell fraction. Ribulose 1,5-bisphosphate carboxylase (EC 4.1.1.39) (RuBPC) and phosphoenolpyruvate carboxylase (EC 4.1.1.31) (PEPC) were assayed, and chlorophyll determinations and protein estimations were made on both fractions. As expected, PEPC showed higher activities in the M fractions; contrary to expectation RuBPC was present in M cell fractions in the six dicotyledonous C4 plants tested. The relative high RuBPC activities found in the M fraction could not be explained in terms of bundle sheath contamination.
An unexpectedly large proportion of C4 grasses was found in a moderately temperate and moist Himalayan location during monsoon period. 79 % of total grasses occurring in the area were found to be C4. Several grasses hitberto unreported as C4 háve now been recorded. The principál cause for the natural abundance of C4 species is presumably low atmospheric CO2 levels rallua' tlian the aridity and warmer temperatures. The finding adds a new dimension to our knowledge of natural distribution of the C4 species.
Modelling the exchange and transformation of matter and energy in ecosystems requires the development of hierarchical structured models of the considered ecosystem compartments. In this context, a model describing the coupled CO2 and H2O gas exchange of a winter wheat canopy was developed and calibrated. The formidation of the model was related to the problems of linking processes at different systém levels. For model calibration, ecophysiological gas exchange characteristics and micro-meteorological data were obtained on both leaf and canopy levels and completed by results of structural and Chemical plant analysis. The gas exchange was measured by a computer-controlled multi-channel systém. On the basis of this data pool, the canopy gas fluxes were calculated by the model as the integrál of the corresponding local fluxes over the area elements of the canopy. The model describes correctly physiological interactions and gas exchange characteristics at both the leaf and canopy levels.
The unknown oligochaete host in the life-cycle of Hoferellus carassii Achmerov, 1960 was identified as a member of the family Naididae, the genus Nais (most probably Nais elinguis). The aurantiactinomyxon spore found by El-Matbouli et al. ( 1992a) is demonstrated to be the actinosporean stage of Hoferellus carassii. The development of this spore within the naidid host is described by electron microscopy, and the results compared with those of Janiszewska (1955, 1957) and Marqués (1984. 1986) for Actinosporea originally described as a separate group of parasites. Additionally the plasmodial development of H. carassii within the urinary bladder of the goldfish (Carassius auratus auratus Linnaeus, 1758) is described.
A new nematode, Dichelyne alatae sp. n., is described on the basis of the worms recovered from the intestine of the whiting, Sillaginopsis panijus (Perciformes: Sillaginidae) from the estuary of the river Hooghly at Kalyani, West Bengal, India. Dichelyne alatae differs from congeners in having a small body size, deirids posterior to the oesophagus, short and wide caudal alae at the level of cloacal opening, unequal, alate spicules, a shield-shaped gubemaculum, a different number of caudal papillae and a conical tail with spines in its distal region.