Syrticola mediterraneus n. sp., a harpacticoid copepod from the Bay of Calvi,Corsica

Syrticola mediterraneus n. sp. belonging to the family Cylindropsyllidae Sars (sensu Lang, 1948) is described from the Bay of Calvi (Corsica). The species is closely related to (?) Notopontia galapagoensis Mielke, 1982 and Syrticola flandricus Willems & Claeys, 1982. The former species is now transferred to the genus Syrticola as Syrticola galapagoensis n. comb.     

Evidence for reverse cholesterol transport in vivo from liver endothelial cells to parenchymal cells and bile by high-density lipoprotein.

Acetylated low-density lipoprotein (acetyl-LDL), biologically labelled in the cholesterol moiety of cholesteryl oleate, was injected into control and oestrogen-treated rats. The serum clearance, the distribution among the various lipoproteins, the hepatic localization and the biliary secretion of the [3H]cholesterol moiety were determined at various times after injection. In order to monitor the intrahepatic metabolism of the cholesterol esters of acetyl-LDL in vivo, the liver was subdivided into parenchymal, endothelial and Kupffer cells by a low-temperature cell-isolation procedure. In both control and oestrogen-treated rats, acetyl-LDL is rapidly cleared from the circulation, mainly by the liver endothelial cells. Subsequently, the cholesterol esters are hydrolysed, and within 1 h after injection, about 60% of the cell- associated cholesterol is released. The [3H]cholesterol is mainly recovered in the high-density lipoprotein (HDL) range of the serum of control rats, while low levels of radioactivity are detected in serum of oestrogen-treated rats. In control rats cholesterol is transported from endothelial cells to parenchymal cells (reverse cholesterol transport), where it is converted into bile acids and secreted into bile. The data thus provide evidence that HDL can serve as acceptors for cholesterol from endothelial cells in vivo, whereby efficient delivery to the parenchymal cells and bile is assured. In oestrogen-treated rats the radioactivity from the endothelial cells is released with similar kinetics as in control rats. However, only a small percentage of radioactivity is found in the HDL fraction and an increased uptake of radioactivity in Kupffer cells is observed. The secretion of radioactivity into bile is greatly delayed in oestrogen-treated rats. It is concluded that, in the absence of extracellular lipoproteins, endothelial cells can still release cholesterol, although for efficient transport to liver parenchymal cells and bile, HDL is indispensable.     

Immunotargeting of daunomycin to localized and metastatic human colon adenocarcinoma in athymic mice

Summary A monoclonal antibody (designated SF25), which recognizes a protein antigen expressed on a large number of human colon carcinomas, was used for drug targeting. Daunomycin-antibody conjugates were prepared by two previously described procedures. In one, the drug was bound to the antibody through a spacer of small molecular mass (cis-aconitic acid), while in the other a dextran bridge served as the link between drug and antibody. High substitution rates of drug to antibody were obtained using the latter binding procedure. Both conjugates were tested in vitro against two human colon carcinoma cell lines, LS180 and KM-12. The efficacy of a daunomycin-dextran-SF25 antibody conjugate was tested against colon carcinoma LS180 tumors transplanted at different sites into athymic mice. The specific conjugate was significantly more inhibitory to a subcutaneous tumor growth than its components or their mixture. SF25 antibody alone showed antitumoral effects against all three forms of transplanted tumor tested, namely, local, metastatic or intrahepatic, whereas daunomycin, on its own, was effective only against the subcutaneous tumor. Binding of daunomycin to dextran partially improved its inhibitory activity against the metastatic tumor. The conjugate, daunomycin-dextran-SF25 antibody reduced the number of metastatic foci, increased the survival rate and delayed death. Yet against lymph node metastases it was not significantly better than a mixture of both constituents. However, results obtained with an intrahepatic tumor, a model that mimics the natural progression of the disease, resembled those described with the subcutaneous tumor. Daunomycin-dextran-SF25 antibody was significantly more effective than all components separately and than a mixture of drug and antibody, provided a highly drug-substituted conjugate was used.     

Large-scale preparation and reconstitution of apo-flavoproteins with special reference to butyryl-CoA dehydrogenase from Megasphaera elsdenii. Hydrophobic-interaction chromatography

A new method is described for the large-scale reversible dissociation of flavoproteins into apoprotein and prosthetic group using hydrophobic-interaction chromatography. Lipoamide dehydrogenase from Azotobacter vinelandii and butyryl-CoA dehydrogenase from Megasphaera elsdenii are selected to demonstrate the usefulness of the method. In contrast to conventional methods, homogeneous preparations of apoproteins in high yields are obtained. The apoproteins show high reconstitutability. The holoenzymes are bound to phenyl-Sepharose CL-4B at neutral pH in the presence of ammonium sulfate. FAD is subsequently removed at pH 3.5-4.0 by addition of high concentrations of KBr. Large amounts of apoenzymes (200-500 mg), showing negligible residual activity, are eluted at neutral pH in the presence of 50% ethylene glycol. The holoenzyme of lipoamide dehydrogenase can be reconstituted while the apoprotein is still bound to the column or the apoenzyme can be isolated in the free state. In both cases the yield and degree of reconstitution of holoenzyme is more than 90% of starting material. Apo-lipoamide-dehydrogenase exists mainly as a monomer in solution and reassociates to the native dimeric structure in the presence of FAD. The apoenzyme is stable for a long period of time when kept in 50% ethylene glycol at -18 degrees C. Steady-state fluorescence-polarization measurements of protein-bound FAD indicate that reconstituted lipoamide dehydrogenase possesses a high stability which is governed by the low dissociation rate constant of the apoenzyme-FAD complex. The holoenzyme of butyryl-CoA dehydrogenase cannot be reconstituted when the apoenzyme is bound to the column. However, stable apoprotein can be isolated in the free state yielding 50-80% of starting material, depending on the immobilization conditions. The coenzyme A ligand present in native holoenzyme is removed during apoprotein preparation. The apoenzyme is relatively stable when kept in 50% ethylene glycol at -18 degrees C. From kinetic and gel filtration experiments it is concluded that the reconstitution reaction of butyryl-CoA dehydrogenase is governed by both the pH-dependent hydrodynamic properties of apoenzyme and the pH-dependent stability of reconstituted enzyme. At pH 7, the apoenzyme is in equilibrium between dimeric and tetrameric forms and reassociates to a native-like tetrameric structure in the presence of FAD. The stability of reconstituted enzyme is strongly influenced by the presence of CoA ligands as shown by fluorescence-polarization measurements. The degree of reconstitution of butyryl-CoA dehydrogenase is more than 80% of the original specific activity under certain conditions.(ABSTRACT TRUNCATED AT 400 WORDS)     

Anti-idiotypic treatment of BALB/c mice induces CRIa-bearing suppressor cells with altered Igh-restricted function

The ABA-specific antibody response of A/J mice (Igh Ie) is dominated by the CRIa idiotype. In contrast, BALB/c mice (Igh Ia) do not produce CRIa-bearing anti-ABA antibodies after antigenic challenge. We have shown previously that treatment with rabbit anti-CRIa (R-anti-CRIa) induces the expression of "CRIa-like" anti-arsonate antibodies in BALB/c mice. In the present report, we demonstrate that R-anti-CRIa treatment enables BALB/c mice to respond to A/J ABA-specific first-order suppressor molecules (TsF1). Manipulated BALB/c also produced CRIa bearing ABA-specific immune response. Thus, R-anti-CRIa treatment induces a change in the characteristic Igh restriction pattern typically seen in this system. These data suggest that Igh restriction in the ABA-specific T suppressor cell pathway is the result of CRIa+ dominance in the T suppressor cell response of A/J mice. The effectiveness of idiotypic manipulation in inducing the expression of a given idiotype at both the B cell and T suppressor cell levels is discussed.     

Release of Inorganic Phosphate from Irradiated Yeast: Radiation Biodosimetry and Evaluation of Radioprotective Compounds

When cells of bakers' yeast, Saccharomyces cerevisiae, were irradiated with ionizing radiation, inorganic phosphate, ninhydrin-reactive material, and substances absorbing at 260 mmu were released into the suspending medium. The amount of inorganic phosphate released depended on the radiation dose and on the temperature and pH during irradiation. The concentration of yeast cells did not affect the phosphate yield per milligram of yeast. It is suggested that the release of phosphate may serve as an index of the total radiation environment (i.e., as a biodosimeter) where radiation inactivation of microrganisms is of primary importance, e.g., in radiation preservation of foods. The somewhat limited range of the yeast biodosimeter (ca. 0.5 to 1.75 Mrad) may be extended by use of other more resistant microorganisms, such as bacterial spores. Compounds which have been reported as protecting microorganisms and mammals against the lethal effect of ionizing radiation also inhibited the radiation-induced release of inorganic phosphate from yeast. This phosphate release system is proposed as the basis for an economical, rapid supplement to screening procedures in the evaluation of radioprotective compounds.     

Eight newSalmonella types

Summary Eight newSalmonella types are described.S. houten, 43; Z₄, Z₂₃ :−, was isolated from a frog,S.tuindorp, 43: Z₄, Z₃₂: −,S. vleuten, 44: fg: −,S.zeist, 18: Z₁₀: Z₆, andS.soesterberg. 21: Z₄, Z₂₃: −, were isolated from lizards. S. kralingen (8), 20: y: Z₆, was isolated from peanuts andS. assen, 21: a: −, was isolated from a swine. All these strains were isolated in the Netherlands. S.mim, 13, 22: a: 1,6, was isolated from a rat in Ghana.