Effect of tunicamycin and endoglycosidase H and F on the estrogen regulated 52000-Mr protein secreted by breast cancer cells

The glycosylation and immunoreactivity of an estrogen regulated glycoprotein secreted by breast cancer cells in culture and defined by its molecular mass (52 000-Mr protein) have been studied indirectly using an inhibitor of glycosylation and specific endoglycosidases. The protein and its deglycosylated forms were immunoprecipitated with specific monoclonal antibodies to the 52 000-Mr protein and analyzed by SDS polyacrylamide gel electrophoresis. The 52 000-Mr protein was intensely labelled by [3H] mannose or [35S] methionine. Tunicamycin treatment of the cells, endoglycosidase H or endoglycosidase F digestion of conditioned media, gave two identical deglycosylated forms of 50 000-Mr and 48 000-Mr which remained immunoreactive. The 48 000-Mr protein, in contrast to the 52 000 and 50 000-Mr proteins, was unable to bind concanavalin A. The 52 000-Mr protein was resolved into five spots of decreasing pI on two-dimensional gels following immunoprecipitation. Endoglycosidase H treatment decreased the molecular weight and reduced the intensity of spots of lower pI, suggesting that the N-glycosylated chains contain acidic molecules. We conclude that: The 52 000-Mr secreted protein contains at least two high mannose or hybrid N-glycosylated chains of approximately 2,000 molecular weight corresponding to 8% of the mass of the 52 000-Mr protein. The two types of monoclonal antibodies (site 1 and 2) raised against the 52 000-Mr glycoprotein are still able to recognize the 48 000-Mr N-deglycosylated form indicating that they do not interact with the N-glycosylated moiety of the molecule.     

Degradation of lignin and lignin related compounds by protoplasts isolated from Fomes annosus

Protoplasts from a lignolytic fungus Fomes annosus were prepared through enzymatic hydrolysis of mycelium utilizing Novozym, a wall lytic enzyme preparation. Isolated protoplasts and living mycelium were compared in their ability to degrade ¹⁴C-labelled lignin related phenols and dehydropolymers of labelled coniferyl alcohol (synthetic lignin). The amounts of ¹⁴CO₂ released from O¹⁴CH₃-groups, ¹⁴C-2-side chains and ¹⁴C-rings by protoplasts was in the same range as those for intact mycelium. The methoxyl groups of synthetic lignin were more rapidly metabolized by protoplasts than by mycelium. When calculated in dpm of released ¹⁴CO₂ per mg protein the decomposition of ¹⁴C-labelled synthetic lignin and lignin-related monomers in a hyphae-free system of protoplasts was considerable higher than that obtained by the intact mycelium. The presence of intact hyphae is thus not necessary for lignin degradation to occur.Non-common-abbreviations used DHP Dehydropolymer of coniferyl alcohol - LS lignosulfonates prepared from DHP     

Habitat preferences of aphidophagous coccinellids [Coleoptera]

From May to July 1982 and 1983, coccinellids were sampled in habitats that differed in aphid density, insolation, and host plant type. The number of adults ofCoccinella 7-punctata (CS),C. 5-punctata (CQ),Propylea 14-punctata (PQ),Adonia variegata (AV),Adalia bipunctata (AB),A. 10-punctata (AD), andCalvia 14-guttata (CA) were recorded. AB, AV and CS preferred high, while CQ tolerated low aphid density. CQ, CS, AB and AV preferred sunny, while AD and CA tolerated shaded conditions. CS and AV preferred herbaceous plants, AD and CA large plants, particularly trees, AB showed little specialization, CQ preferred trees early in the season and sparse herbaceous plants later. PQ appeared to be a generalist with a wide tolerance of all these factors, but with a tendency to move from trees to herbaceous plants as the season progressed. Habitats with a high abundance of a species were assumed to be those with on optimum combination of the preferred conditions. There were slight differences in the breadth of habitat preferences, and a little habitat overlap between species. The tendency to aggregate was greater in AB than in other species. Annual variations in species abundance influenced the number of habitats occupied, but not the abundance in the favoured places.     

Four new and other 4α-methylsterols in the seeds of Solanaceae

Four new 4α-methylsterols in the seeds of Solanaceae were identified as 31-norlanost-9(11)-enol, 24-methyl-31-norlanost-9(11)-enol, 4α,24-dimethylcholesta-7,24-dienol and 4α-methyl-24-ethylcholesta-7,24-dienol. The other 4α-methylsterols identified in the seeds were 31-norcycloartanol, 31-norcycloartenol, cycloeucalenol, 31-norlanost-8-enol, 31-norlanosterol, obtusifoliol, 4α,14α,24-trimethylcholesta-8,24-dienol, 4α-methylcholest-8-enol, lophenol, 24-methyllophenol, 24-ethyllophenol, gramisterol and citrostadienol. The distribution of these seventeen 4α-methyl- sterols in the seeds of eight species of the Solanaceae was determined.     

Manipulation of fatty acid composition of membrane phospholipid and its effects on cell growth in mouse LM cells

Fatty acid composition of the phospholipids of mouse LM cells grown in suspension culture in serum-free chemically defined medium was modified by supplementing the medium with various fatty acids bound to bovine serum albumin.Following supplementation with saturated fatty acids of longer than 15 carbons (100 μM) profound inhibition of cell growth occurred; this inhibitory effect was completely abolished when unsaturated fatty acids were added at the same concentration. Supplementing with unsaturated fatty acids such as linoleic acid, linolenic acid or arachidonic acid had no effect on the cell growth.Fatty acid composition of membrane phospholipids could be manipulated by addition of different fatty acids. The normal percentage of unsaturated fatty acids in LM cell membrane phospholipids (63%) was reduced to 35–41% following incorporation of saturated fatty acids longer than 15 carbon atoms and increased to 72–82% after addition of unsaturated fatty acids.A good correlation was found between the unsaturated fatty acid content of membrane phospholipids and cell growth. When incorporated saturated fatty acids reduced the percentage of unsaturated fatty acids in membrane phospholipids to less than 50%, severe inhibition of the cell growth was found. Simultaneous addition of an unsaturated fatty acid completely abolished this effect of saturated fatty acids.     

The origin of the dendritic reticulum cell

Summary ¹⁴C-5,6-DHT-Melanin was injected into the left lateral ventricle of adult rats and its fate followed by light and EM autoradiography and by TEM of structures identified as labeled in preceding light micrographs. Shortly after injection, melanin particles were seen ingested by supraependymal and epiplexus cells, by cells residing in the pia-arachnoid, i.e. free subarachnoidal cells and perivascular cells, and by subependymally located microglia-like cells with intraventricular processes. Up to day four, an increase in the number of labelled phagocytes in the CSF was noted which transformed into typical reactive macrophages. After this time, many intraventricular melanin-laden phagocytes formed rounded clusters; cells of such clusters were subsequently found to invade the brain parenchyma by penetrating the ependymal lining and to accumulate in the perivascular space of brain vessels. ¹⁴C-Melanin-storing macrophages were found in the marginal sinus of the deep jugular lymph nodes suggesting emigration of CNS-derived phagocytes via lymphatics or prelymphatics that contact the subarachnoidal space compartment. This does not exclude the possibility that some of the macrophages leave the brain via the systemic circulation by penetrating the vascular endothelium; these may be disposed of in peripheral organs other than the lymph nodes.The ability of supraependymal, epiplexus, free subarachnoidal and perivascular cells in the pia and of subependymal microglia cells to accumulate synthetic melanin by phagocytosis suggests that these cells are local variants of the same type of resting potential phagocytes of the mammalian brain. The present study shows that ¹⁴C-5,6-DHT-melanin is an ideal phagocytic stimulant and marker for phagocytosis.Supported by grants from the Deutsche Forschungsgemeinschaft     

Membrane damage by a toxin from the sea anemone Stoichactis helianthus. II. Effect of membrane lipid composition in a liposome system

In the first paper of this series, it was shown that a toxin from the sea anemone Stoichactis helianthus increased the permeability of black lipid membranes due to transmembrane channel formation. In the present study, we have used liposomes to examine the reactivity of the toxin with different phospholipids. Membrane damage was assessed by measuring the release of ⁸⁶Rb⁺ and ¹⁴C-labeled membrane lipid. For the different lipids, the rank order of marker release was: sphingomyelin > C18: 2 phosphatidylcholine > C18: 1 phosphatidylcholine > C18: 0 phosphatidylcholine > C16: 0 phosphatidylcholine = C14: 0 phosphatidylcholine. In C14: 0 and C16: 0 phosphatidylcholine liposomes there was no ¹⁴C-labeled lipid release and only 13 to 16% ⁸⁶Rb⁺ release which corresponds to the ⁸⁶Rb⁺ content in the outermost aqueous shell of multilamellar liposomes. This indicates that membrane damage was limited to the outermost bilayer. In liposomes prepared with the other lipids, the extent of release of both markers increased proportionately with the length and the degree of unsaturation of the lipids' acyl side chains. Sphingomyelin liposomes were the most susceptible with 47% of the ¹⁴C-labeled lipid marker and 90% of the ⁸⁶Rb⁺ marker being released. The large extent of ¹⁴C-labeled lipid release is attributed to a detergent-like activity of the toxin which presumably is due to the amphipathic nature of the protein. Thus, the toxin can inflict membrane damage in two ways: (1) channel formation, and (2) detergent action. The importance of one mechanism or the other apparently varies depending on membrane structure and lipid composition.     

Gap junctional coupling between the JGA and the glomerular tuft

Summary Cytochalasin B (CB) administered simultaneously with a mitogenic dose of concanavalin A (Con A) interferes with the activation process. This interference involves structural alterations of cellular membrane which do not include a reduced Con A-binding capacity. This conclusion is supported by the observation of deformities in both nuclear and cytoplasmic membranes in Con A-activated lymphocytes subsequently treated with CB. The high incidence of membrane blebs and pseudomyelin bodies in the cytoplasm points to a general effect of CB on the structural organization of membrane which may secondarily interfere with some specific event such as generation or transfer of signals for activation or cytokinesis.     

Effect of environmental temperature on biosynthesis of liver phosphatidyl-choline in the trout (Salmo gairdnerii)

1. 1.The changes in fatty acid composition of trout liver phosphatidyl-choline, when the environmental temperature was increased, resulted in modifications in the amounts of the different molecular species.

2. 2.In vivo, incorporation of ³²P occurred more rapidly in the molecular species with high degree of unsaturation.Temperature acclimation did not modify the relative proportions of label shown in the five subfractions.

3. 3.In vitro incorporation of ¹⁴C-methyl-choline also occurred more rapidly in the most unsaturated molecular species. However, when the incubation temperature was raised, the proportion of label decreased in the unsaturated fractions.

New neutral diterpenes from southern pine tall oil

Five new diterpene natural products isolated from southern pine (Pinus spp.) tall oil were characterized as 8(14),15-pimaradiene-3β,18-diol, 19-hydroxy-15,16-dinorlabd-8(17)-en-13-one, 8,13β-epoxy-14-labden-6α-ol, 8,11, 13-abietatriene-15,18-diol and 9,10-secoabieta-8,11,13-trien-18,10-olide.