Depletion of Schistosoma mansoni lung-stage schistosomula cholesterol by methyl-beta-cyclodextrin dramatically increases specific antibody binding to surface membrane antigens

Schistosoma mansoni lung-stage larvae appear to not bind antibodies from radiation vaccine or infection sera in the membrane immunofluorescence test. However, treatment of ex vivo lung-stage schistosomula with methyl-beta-cyclodextrin, a hydrophobic oligosaccharide that specifically extracts cholesterol from plasma membranes, induced readily detectable binding of specific antibodies in a concentration- and time-dependent manner. Surface membrane antigen binding of specific antibodies was also conclusively demonstrated by quantitative absorption of anti-schistosome sera with intact ex vivo larvae. These data together suggest that confinement of lung-stage schistosomula surface membrane antigens in cholesterol-rich sites allows only monovalent antibody binding, which can be detected by absorption and not by direct serology.     

The tyrosine phosphatase 1B regulates linker for activation of T-cell phosphorylation and platelet aggregation upon FcgammaRIIa cross-linking

Human platelets express the receptor for immunoglobulin G, FcgammaRIIa, that triggers cell aggregation upon interaction with immune complexes. Here, we report that the rapid tyrosine phosphorylation of the Linker for Activation of T-cell (LAT) in human platelets stimulated by FcgammaRIIa cross-linking was followed by its complete dephosphorylation in an alphaIIb/beta3 integrin-dependent manner. Concomitant to LAT dephosphorylation, the protein tyrosine phosphatase 1B (PTP1B) was activated through a mechanism involving its proteolysis by calpains downstream of integrins. Both PTP1B and LAT were associated with the actin cytoskeleton complex formed during platelet aggregation. Moreover, phospho-LAT appeared as a good substrate of activated PTP1B in vitro and these two proteins interacted upon platelet activation by FcgammaRIIa cross-linking. The permeant substrate-trapping PTP1B (TAT-PTP1B D181A) partly inhibited LAT dephosphorylation in human platelets, strongly suggesting that this tyrosine phosphatase was involved in this regulatory pathway. Using a pharmacological inhibitor, we provide evidence that PTP1B activation and LAT dephosphorylation processes were required for irreversible platelet aggregation. Altogether, our results demonstrate that PTP1B plays an important role in the integrin-mediated dephosphorylation of LAT in human platelets and is involved in the control of irreversible aggregation upon FcgammaRIIa stimulation.     

Cytokines synergistically induce osteoclast differentiation: support by immortalized or normal calvarial cells

Conditionally immortalizedmurine calvarial (CIMC) cells that support differentiation ofprecursors into mature osteoclasts were isolated. All six CIMC celllines supported osteoclast differentiation in response to1,25-dihydroxyvitamin D₃ or interleukin (IL)-11. CIMC-4cells also supported osteoclast differentiation in response to tumornecrosis factor (TNF)-, IL-1, or IL-6. The resultant multinucleated cells expressed tartrate-resistant acid phosphatase andformed resorption lacunae on mineralized surfaces. CIMC-4 cells,therefore, establish an osteoclast differentiation assay that isresponsive to many cytokines and does not rely on isolation of primarystromal support cells. Low concentrations of the cytokines synergistically stimulated differentiation when osteoclast precursors were cocultured with either CIMC-4 cells or primary calvarial cells.Osteoclast differentiation induced by all stimuli other thanTNF- was completely blocked by osteoprotegerin, whether thestimulators were examined alone or in combination. Moreover, study ofprecursors that lack TNF- receptors showed that TNF- inducesosteoclast differentiation primarily through direct actions onosteoclast precursors, which is a distinct mechanism from that used bythe other bone-resorptive agents examined in this study.

     

Selenoprotein inAspergillus terreus

Aspergillus terreus, a moderately selenium-tolerant fungus, metabolized⁷⁵ Se-selenite into several protein seleno-amino acids: selenomethionine and selenocysteine, as well as, nonprotein seleno-amino acids, selenocystathionine, and y-glutamyl selenomethyl selenocysteine. The results indicate the failure of the fungus to discriminate between sulphur and selenium. Selenium was also incorporated into several proteins of different molecular weights, mostly of low molecular weight proteins. Labeled studies showed the presence of high levels of selenomethionine and selenocysteine in the protein hydrolysate. The actual incorporation of protein selenoamino acids into the fungal protein was proven. The results demonstrated a finding that detracts from previous held views.     

Anatomical and Molecular Identification of Ornamental Plant <i>Ficus</i> L. Species

This present study includes twelve species that represent the Ficus genus, namely; aspera, carica, tinctoria subsp. gibbosa, hirta, hispida, neriifolia, palmata, pumila, racemosa, septica, sur, and sycomorus, belonging to the Moraceae family. The species samples were collected from various locations in Egypt. The study focused on the anatomical and molecular characteristics of mature foliage leaves. Since the identification and classification of taxa are highly dependent on the anatomical features of leaves, the anatomical characteristics were recorded in the form of a comparison between the examined plants in the data matrix. This study aims to contribute to the identification of the studied species based on the anatomical details of the matured leaves. Anatomical characterization includes the variations in upper and lower epidermal layers that are covered by a thin or thick cuticle; the number of palisade and spongy layers; crystals; secretory elements; lithocysts; the midrib zone has parenchyma associated with mechanical tissue, vascular system, and investigation of trichomes; on the other hand, in the current study, the phylogenetic analysis was conducted by using the ITS and 5.8 S sequences. From the analysis of all the available data, it could be stated that there is an overall agreement with the anatomical character dendrogram.     

Early termination of pregnancy: A comparative study of intrauterine prostaglandin F2α and vacuum aspiration

The relative safety and effectiveness of vacuum aspiration and the intrauterine administration of 5 mg PGF_2α for terminating pregnancies within two weeks of a missed menstrual period were evaluated in a study where subjects were randomly assigned to procedures; 100 patients were aborted with vacumm aspiration and 100 patients were aborted with PGF_2α. All PGF_2α-treated patients were premedicated with meperidine, diazepam and atropine. Complications were infrequent with either of the procedures. Vomiting occurred more frequently during the PGF_2α procedure (30.0%) than during the vacuum aspiration procedure (9.0%). The intrauterine instillation of PGF_2α successfully terminated all pregnancies. One patient continued to be pregnant after the vacuum aspiration procedure. Based on the results of this study both study procedures appeared to be safe and effective for terminating early first trimester pregnancies.     

Papers to appear in forthcoming issues

Cells from the peripheral blood of two unrelated individuals were separated by velocity sedimentation, and fractions containing “pure” granulocytes and lymphocytes were prepared. One-way mixed leukocyte cultures (MLC's) were performed using these fractions. It was noted that the lymphocyte-versus-lymphocyte fractions gave a good response in the MLC and addition of granulocytes inhibited the response.     

Seroprevalence of Cryptosporidium parvum and Neospora caninum in cattle in the southern Kyushu region of Japan

Cryptosporidium parvum and Neospora caninum are common parasites in domesticated cattle worldwide, including in Japan. We carried out a serological survey to detect C. parvum and N. caninum infection among cattle in the southern Kyushu region of Japan—including the small islands—by indirect enzyme-linked immunosorbent assay based on recombinant antigens. We found that total seropositivity in 570 Japanese black cattle was 96.3% for C. parvum and 18.4% for N. caninum. Although seroprevalence was correlated with cattle age, differences in the seroprevalence of C. parvum among age groups were not statistically significant. On the other hand, N. caninum seroprevalence increased with age, suggesting horizontal transmission through ingestion of food or water contaminated with oocysts. These findings underscore the importance of monitoring C. parvum and N. caninum in cattle and implementing measures to prevent the spread of infection to other livestock and to humans.