The occurrence of caulonema-specific proteins in different moss species

Soluble proteins extracted with Tris-buffer pH 8.8 from different mosses are analysed by microgelelectrophoretic method for comparison to the specific proteins present only in the caulonema of Funaria hygrometrica. The protein patterns are also compared with those of liverwort, fern gametophytes and sporophytes and tobacco. It is observed that the caulonema specific proteins are only present in the caulonema of these mosses and are absent in other plants.Abbreviations CSP caulonema specific proteins     

Determination of the configurations of lactic and glyceric acids from human serum and urine by capillary gas—liquid chromatography

The separation of the enantiomers of lactic and glyceric acids can be achieved by capillary gas chromatography on SP-1000 using the corresponding O-acetylated menthyl esters. The structures of the derivatives were proved by proton magnetic resonance spectroscopy and mass spectrometry. The method has been used for the determination of the absolute configurations of lactic and glyceric acids isolated from serum and urine from different patients.     

Pulsation of nuclei in insect oocytes is reversibly inhibited by cytochalasin B

Oocyte nuclei of the dipteran insect Heteropeza pygmaea display swift pulsating movements during in vitro follicle formation in the ovaries. Low doses of cytochalasin B (CB) completely inhibit the nuclear movements within a few minutes and cause the nuclei to assume spherical shapes. If the drug is removed, nuclear pulsation is resumed within 5–10 min. Phalloidin and colchicine do not affect the nuclear movements. Actin is shown by indirect immunofluorescence microscopy to be present in considerable amounts all over the cytoplasm of the oocytes. It is concluded that microfilaments are responsible for pulsation of the oocyte nuclei, whereas microtubules are not involved.     

Study on the composition-structure relationship of lipophorins

High density lipophorin (HDLp is the main lipoprotein found in resting insect hemolymph. It has, in general, two molecules of apolipoproteins: apoLp-I (250 kDa) and apoLp-II (80 kDa) and a variable lipid content which ranges from 35% to 59% (w/w). Diacylglycerols (DG), phospholipids (PL), and hydrocarbons (HC) are the main lipid components, whereas cholesterol and triacylglycerols are minor components. DG content varies from 7 to 30%, PL from 11 to 24%, and HC from 0 to 15%. In order to determine the relationship between the lipid composition and the arrangement of lipid and protein components in the lipoprotein particle, a density-composition structural model was designed. The model was established by means of 12 sets of data on lipophorin density-composition relationships, and model validity was determined throughout lipoprotein space- and surface-filling conditions. Despite the differences among the lipid compositions of lipophorins, it is concluded that there are several unifying structural restrictions that govern the molecular organization of lipophorins. Quantitative treatment of the model indicates that lipophorin structure is consistent with the following. 1) Spherical particles with a protein-rich outer layer of approximately 20-21 A thickness, comprised of proteins, phospholipids, cholesterol, and small amounts of DG, and a lipid-rich core composed of HC, TG, and almost all the lipophorin DG. 2) Apolipophorins have a lipid-embedded localization within the lipoprotein particle. They might represent one of the few examples of proteins containing beta-shift structure, exerting strong hydrophobic interaction and having a lipid-embedded localization.(ABSTRACT TRUNCATED AT 250 WORDS)     

Paleolimnology of Qilu Hu,Yunnan Province,China

Qilu Hu is a large (A = 36.9 km²), shallow (z_max = 6.8 m) lake that lies at an elevation of 1797 m above msl on the Yunnan Plateau, southern China. Lake waters are hard (Mg = 3.2m eq L^–1, Ca = 1.3 meq L^–1 ), fresh (conductivity = 380 S cm ^–1), and productive (Secchi < 40 cm). An 11-m sediment core has a basal ¹⁴C age of 30960 ± 860 B.P. Sediments between 11 m and 6 m are high in % dry weight, rich in clay components Al₂O₃, Fe₂O₃, K₂O, MgO, and low in organic C (6.1%), carbonate-C (<1.0%), total N (<3.2 mg g^–1), and total S (<-1.7 mg g^–1). Diatoms and pollen indicate open-water conditions between 9.0 m and 6.0 m (1342011790 B.P.). Above 6.0 m, CaCO₃ and organic matter concentrations increase relative to clastics. The transition marks a change to shallow-water conditions as inferred from diatoms and pollen, and probably reflects a shift to drier climate. Uppermost (80-0 cm) red clays were deposited rapidly, probably as a consequence of recent (decades to centuries) riparian disturbances (e.g. agriculture, lake-bottom reclamation, urban development). Dates assigned to events in the Qilu Hu profile are tentative because of potential hard-water-lake error.     

Biotechnological production of unnatural L-amino acids from D,L-5-monosubstituted hydantions. II. L-α- and L-β-naphthylalanine

Summary Resting cells ofArthrobacter sp. (DSM 3745) with the ability to form L-tryptophan from D,L-5-(3-indolylmethy)hydantoin were used for the bioconversion of D,L-5-- and D,L-5--naphthylmethylhydantoin (D,L-5-- and D,L-5--NMH) to the corresponding L-amino acids. Under the optimal reaction conditions of pH 9.7 and 40°C specific productivities of 0.2 (-naphtylalanine) and 0.6 (-naphtylalanine) mM amino acid x g cell dry mass^–1 x h^–1 were obtained in a 0.1 M Na₂CO₃/NaHCO₃-buffer in a strirred bioreactor.     

An efficient method for isolation of plasmid DNA from methylotrophic bacteria

A method, suitable for the isolation of closed circular plasmid DNA from methylotrophic bacteria is described. Improvement of cell lysis was achieved by butanol extraction of cells before application of the lytic agent. Using this method, cryptic plasmids of 7.8, 14, 36 and 200 kb were purified from soil-isolated methylotrophs.     

Heterogeneity of cell surface endothelin receptors

Two distinct cell surface endothelin receptors were identified, namely a 73-kDa protein referred to as ET-R1 and a 60-kDa protein named ET-R2. ET-R1 was expressed as the sole endothelin receptor on rat A10 vascular smooth muscle cells and C6 glial cells. Binding of 125I-ET-1 to these cells was inhibited by 50-200 pM endothelin-1 and -2, whereas endothelin-3 did not compete for this receptor subtype. Binding of 125I-ET-1 to intact A10 and C6 cells was reversible, indicating that ET-R1 is located on the cell surface. Affinity labelling of a single 73-kDa band on sodium dodecyl sulfate-polyacrylamide gels by 125I-ET-1 in A10 and C6 cells was inhibited by endothelin-1 but not by endothelin-3. In A10 cells, endothelin-1 but not endothelin-3 elicited a concentration-dependent increase in intracellular inositol trisphosphate levels. ET-R1 was also expressed in cultured rat glomerular mesangial cells based on findings of a subset of receptors with an apparent molecular mass of 73 kDa that bound 125I-ET-1 displacable by endothelin-1 and endothelin-2 but not by endothelin-3. These cells also expressed the ET-R2 receptor subtype, based on findings of a 60-kDa binding site that could be labeled by both 125I-ET-1 and 125I-ET-3. Labeling of ET-R2 by the radioactive endothelins-1 and -3 was inhibited competitively by endothelins-1, -2, and -3. Furthermore, ET-R2 was shown to be a functional receptor, as endothelin-3 caused inositol trisphosphate levels to rise in mesangial cells. An endothelin binding site with high affinity for endothelin-3 was also identified on rat PC12 pheochromocytoma cells, although the apparent molecular mass of this receptor could not be verified by cross-linking studies. Since endothelin-1 or -3 failed to augment inositol trisphosphate levels in these cells, this binding site could represent a third endothelin receptor subtype. Thus, two distinct functional receptors for endothelins were identified on rat cells, namely the 73-kDa ET-R1 which has an exceedingly low affinity for endothelin-3 and the 60-kDa ET-R2 which binds endothelin-3 with high affinity. Whether an additional endothelin receptor subtype exists in PC12 cells remains to be shown with certainty.     

Antibacterial and antimycotic effect of a newly discovered secretion from larvae of an endoparasitic insect,Pimpla turionellae L. (Hym.)

Three analogues of the peptidyl pheromone, pheromone of Saccharomyces kluyveri, synthesized based on the amino acid sequence proposed by Sato et al. (Agric Biol Chem 45:1531–1533, 1981) were tested for both shmoo-inducing and agglutinability-inducing actions. Purified natural pheromone of the yeast showed the highest activity among the peptides tested. When methionine in the peptides was oxidized, the activity decreased significatly. Pheromone of S. kluyveri induced sexual agglutinability in a cells of Saccharomyces cerevisiae, and shmoo in a cells of S. cerevisiae and S. kluyveri. a Pheromone of S. kluyveri had no agglutinability-inducing action on cells of S. cerevisiae. a Cells of S. kluyveri inactivated only pheromone of the same species, but a cells of S. cerevisiae inactivated pheromones of both S. cerevisiae and S. kluyveri.