Complement-dependent lysis of tumor cells by a baboon IgM antibody to a tumor-associated antigen

Summary We developed a high-titer polyclonal antiserum to a glycoprotein tumor-associated antigen (TAA) by immunization of a baboon with the purified glycoprotein antigen. The baboon serum was fractionated into IgG and IgM components by DEAE Affi-Gel blue chromatography. The ability of the baboon IgM anti-TAA antibody to effect tumor cell lysis in the presence of complement was tested using a chromium-release assay. The baboon antibody was able to lyse melanoma target cells (20.8%–71.4% cytolysis), breast carcinoma cells (36.5%–38.9% cytolysis), and a neuroblastoma cell line (35.5% cytolysis) in the presence of complement but did not effect significant lysis of autologous lymphoblastoid cell lines (4.9% cytolysis) or peripheral blood lymphocytes from healthy volunteers (12.6% cytolysis). Cytolysis of melanoma target cells was completely inhibited by preabsorption of the IgM anti-TAA antibody with UCLA-SO-M14 (M14) cells and partially inhibited by preabsorption with several other melanoma cell lines. There was no significant inhibition of tumor cell lysis after preabsorption of the antibody with lymphoblastoid cell lines. Complement-dependent lysis of M14 targets could be blocked by addition of the purified antigen to the antibody prior to incubation with the tumor cells. Our results suggest that the glycoprotein TAA resides on the tumor cell surface and that the baboon IgM anti-TAA antibody recognizes the antigen on the cell surface and is able to fix complement and effect the lysis of the tumor cells.     

Flavonoid glycosides from Cassia alata.

Two new glycosides, chrysoeriol-7-O-(2"-O-beta-D-mannopyranosyl)-beta-D-allopyranos ide and rhamnetin-3-O-(2"-O-beta-D-mannopyranosyl)-beta-D-allopyranosid e, were isolated from the seeds of Cassia alata. The structures were established on the basis of chemical evidence and spectroscopic methods, especially NMR.     

The cellular and molecular regulation of 1,25(OH)2D3 production

The synthesis of 1,25(OH)₂D₃ is a critical control point in the regulation of calcium metabolism, and possibly in the growth and differentiation of a number of cell types. This paper reviews our current understanding of the regulation of this process at the cellular and molecular levels, with the emphasis on the mechanisms of feedback control 1,25(OH)₂D₃ itself, control of parathyroid hormone, the roles of cyclic AMP dependent protein kinase and protein kinase C, and the interaction between the various intracellular regulators of 1,25(OH)₂D₃ production.     

Atypical mannolipids characterize Thy-1-negative lymphoma mutants.

Essentially all eukaryotic cells, including murine lymphomas, express surface proteins, such as Thy-1, which are anchored by a phosphoinositol mannolipid. Putative mannolipid anchor precursors can be detected in these cells. Six distinct Thy-1-negative lymphoma mutants lack complete mannolipids, and three mutants synthesize atypical mannolipids. The absence of complete mannolipids can account for the lack of expression of multiple mannolipid-anchored proteins and may also account for the lack of lipid anchoring in the human disease paroxysmal nocturnal hemoglobinuria. Structural information on the mannolipids of wild-type and mutant cells indicates that anchor biosynthesis in these cells may involve both transmembrane flip-flop of intermediates and a deacylation step.     

Immunocytochemical localization of beta-N-acetyl glucosaminidase in human reproductive organs

Immunocytochemical localization of hexosaminidase activity in human males revealed that the enzyme activity is localized mainly in the Sertoli cells and interstitial tissue of the testis and in the columnar cells of the epididymis. In seminal vesicles, activity was observed around the glandular epithelium in the form of fine granules.     

Studies on the interaction of anesthetic steroids with phosphatidylcholine using 2H and 13C solid state NMR

The effects of the anesthetic steroid alphaxalone and its inactive analog delta 16-alphaxalone on model phospholipid membranes were studied using 13C and 2H solid-state nuclear magnetic resonance spectroscopy. Aqueous multilamellar dispersions of dipalmitoylphosphatidylcholine (DPPC) with specific 13C and 2H labels as endogenous probes at the carbonyl and the C-7 methylene groups, respectively, of the sn-2 chain were used to study the conformational and dynamical properties of the bilayer as a function of temperature. There were no significant changes between the 13C and 2H spectra of the DPPC preparation containing the inactive steroid and that of DPPC with no drug. However, the physiologically active steroid produces significant spectral 2H and 13C changes. These changes include a reduction of the main phase transition temperature and a broadening of that transition. Alphaxalone also increases the relative number of gauche conformers in the liquid-crystalline phase of DPPC and increases the rate of axial diffusion in both the gel and liquid-crystalline phase. The thermotropic properties of the above preparations, as monitored by differential scanning calorimetry, were congruent with the spectroscopic data.     

Effect of some carbamate pesticides on nodulation,plant yield and nitrogen fixation byPisum sativum andVigna sinensis in the presence of their respective rhizobia

Summary Six carbamate pesticides namely 1-naphthol, sevin, dimetilan, trematan, NaDDC and dymid were studied to see their effect on nodulation and nitrogen fixation inPisum sativum andVigna sinensis. Low concentrations of the pesticides have little effect on nodulation and nitrogen fixation, whereas higher concentrations adversely effect these processes. The results also indicate that then sensitivity depends upon the species of the Rhizobium and also the type of the pesticide. Pesticides belonging to the carbamate group differ in their capacity to affect nodulation and nitroge fixation.     

Enhancement of water status by calcium pretreatment in groundnut and cowpea plants subjected to moisture stress

Summary The effect of calcium in the water relations and tolerance to moisture deficits was tested in groundnut and cowpea. In both species, enrichment of tissue with calcium resulted in maintenance of a higher water status under stress associated with low proline accumulation. The extent of membrane damage (as reflected by the absorbance at 273 nm) was lesser in leaves of plants fed with higher levels of Ca⁺⁺ when subjected to simulated stress. The rate of water loss from the leaves of Ca⁺⁺-enriched plants was also lower. The possible role of Ca⁺⁺ in inducing membrane stability and maintenance of higher water status is discussed.     

Plant contents and quality of makhana (Euryale ferox)

Summary As a part of integrated study of makhana, the mineral contents of the plant parts and the fruits of makhana (Euryale ferox) have been presented here. It has been observed that the fruits were not only rich in minerals but also in protein. The plant parts also contained high amounts of micronutrients. Its fruits are, therefore, a good supplement for minerals which are produced from otherwise agriculturally waste (water-logged) areas.     

Differential induction of chromosome puffs in two cell types of Melanagromyza obtusa

The patterns of puffing activity in polytene nuclei of salivary gland (SG) and midgut (MG) tissues of Melanagromyza obtusa have been studied after heat shock (HS), 2-4-dinitrophenol (DNP) or benzamide treatment. This study has revealed that HS and DNP treatments induced the same set of puffs but in a tissue-specific pattern. Benzamide treatment was found ineffective in inducing puffing activity. Some HS genes were also found to be more or less active during normal development, indicating some function in the normal metabolism of the cells.