Isolation of the vitellogenin-binding protein from locust ovaries

A rapid, efficient procedure for the isolation and purification of the vitellogenin binding protein from locust ovarian membranes is described. After solubilization with the nonionic detergent octyl-β-D-glucoside and removal of the detergent, the binding protein is subjected to affinity chromatography on vitellogenin coupled covalently to Affi-Gel 15. The binding protein is eluted with suramin and EDTA at low pH value. Sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis reveals a polypeptide with a molecular weight of 156,000 in the eluted fraction. By ligand blotting this polypeptide could be identified as the vitellogenin binding protein. It retains its high-affinity binding properties. The specific binding of vitellogenin increases from 4.8 μg (intact ovarian membranes) to 170.9 μg (affinity purified binding protein) per mg membrane protein, which corresponds to a purification factor of 35.     

Molecular cloning and characterization of complementary deoxyribonucleic acids corresponding to bovine trophoblast protein-1: a comparison with ovine trophoblast protein-1 and bovine interferon-alpha II

Bovine trophoblast protein-1 (bTP-1) is a secreted glycoprotein that consists of several forms differing slightly in mol wt and isoelectric point. It is produced by bovine conceptuses after about day 15 of pregnancy and is believed to play a key role in signalling the presence of an embryo to the mother. In this study, a series of recombinant cDNA clones corresponding to the mRNA for bTP-1 have been isolated from cDNA libraries representing day 18-19 bovine conceptus poly(A)+ mRNA. Base sequencing of several cDNAs indicated that multiple mRNAs for bTP-1 exist. Northern blotting and primer extension experiments showed that the mRNAs average about 1 kilobase in length. One apparently full-length cDNA clone consisted of 1035 bases up to the beginning of the poly(A) tail. It contained an open reading frame of 195 codons which began at a position 79 bases from the 5' end. Its entire sequence was 85% identical to that of a cDNA for the immunologically related ovine trophoblast protein-1 (oTP-1) and about 79% identical to that for a bovine interferon-alpha II (IFN alpha II). The highest conservation of sequence (greater than 90%) was noted in the 3'-untranslated sequences of the bTP-1 and oTP-1 cDNAs. The deduced amino acid sequence of bTP-1 shared 80% identity with oTP-1, between 45-55% with human, rodent, porcine, and bovine IFNs of the alpha 1 subfamily and about 70% with a bovine IFN alpha II. A single potential site for N-glycosylation was noted at Asn78. These results show that bTP-1, like its ovine counterpart oTP-1, is structurally related to the IFN alpha S. We suggest that these embryonic IFNs play a role in controlling immunoreactions at the trophoblast-uterus interface as well as triggering other maternal responses to pregnancy.     

Mental distress and social conditions and lifestyle in northern Norway.

In a cross sectional survey of risk factors for coronary heart disease three questions about mental distress were included in a questionnaire completed by 13,704 people, 64% of the total population aged 20-54 in one municipality. Overall, 860 (12.5%) of the men and 1141 (16.8%) of the women reported having at least one symptom of mental distress. There were no distinct differences between the age groups. Single people, separated and divorced people, and those who reported that the financial situation of the family during their childhood was difficult reported more mental problems. Heavy smoking, frequent alcohol consumption, and, in men, little or no physical activity in leisure time were also associated with a high prevalence of mental distress. By multiple regression analyses, marital state, financial situation of family during childhood, and current lifestyle were found to be highly significantly associated with mental distress. Including a few questions on mental distress in health surveys provides a way to establish relations between such symptoms and social conditions and lifestyle in large numbers of subjects.     

Differences in the host resistance of Atlantic salmon, Salmo salar L., stocks to the monogenean Gyrodactylussalaris Malmberg, 1957

The susceptibility and resistance of hatchery-reared salmon parr, native to the rivers Neva (U.S.S.R. Baltic Sea), Alta (northern Norway) and Lone (western Norway) (both eastern Atlantic Ocean), to Gyrodactylus salaris from Norway, was examined. The level of resistance to the parasite was assessed from counts, made on anaesthetized salmon, ofthe numbers of G. salaris after an initial experimental exposure (2 weeks) to G. salaris-infected salmon. Three experiments, all in water at c. 12° C, were carried out: (1) 50 Alta and 50 Neva salmon, initial mean parasite intensity c. 12; (2) 50 Lone and 50 Neva salmon, initial mean parasite intensity c. 60; (3) 10 Lone and 10 Neva salmon individually isolated, initial intensity one gravid G. salaris . In both the Norwegian salmon stocks, the G. salaris infrapopulations steadily increased during the experimental period of 5 weeks, in contrast to a prominent decline in the Neva salmon stock, after, respectively: (Exp. 1) week 3, average peak intensity 32.6; (Exp. 2) week 2, average peak intensity 58.7; and (Exp. 3) week 3, average peak intensity 6.3. The hatchery-reared Baltic Neva stock demonstrated both an innate and an acquired resistance towards G. salaris , in contrast to the highly susceptible, Norwegian Alta and Lone salmon stocks.     

Expression of major histocompatibility complex antigens on the bovine placenta

Immunohistochemistry was utilized to determine expression of the major histocompatibility complex (MHC) antigens on Day 8-9 hatched blastocysts and fetal membranes of mid- to late gestation cows and to examine the pattern of leucocytic infiltration into the gravid uterus. Hatched blastocysts were weakly positive for MHC class I antigens. In the mature placenta, chorioallantoic membranes in the interplacentomal area showed positive immunostaining for class I antigens on the chorionic epithelium but had no staining for class II antigens. There was an accumulation of lymphoid cells expressing class II antigens directly beneath the luminal epithelium of the endometrium. In addition, cells staining for leucocyte common antigen were present both within and beneath the luminal epithelium. Some cells positive for class II and leucocyte common antigen (CD45) were also associated with uterine glands. In the placentomes, class I antigens were expressed only on maternal caruncular septa. Fetal cotyledonary villi had no detectable immunostaining for class I and II antigens. No distinct pattern of leucocyte infiltration in the maternal caruncular tissue was observed; the caruncular septa contained some cells that were labelled for CD45 and a few class II-positive cells around blood vessels. The results indicate that the fetal placenta of the cow expresses MHC class I antigens in a regionally defined manner and there is a differential accumulation of lymphoid cells in the uterus.     

Crystals of wild-type, mutated, derivatized and complexed 50 S ribosomal subunits from Bacillus stearothermophilus suitable for X-ray analysis

Three-dimensional single crystals of wild-type and mutated 50 S ribosomal subunits from Bacillus stearothermophilus, as well as crystals of reconstituted subunits containing heavy-atom clusters and complexes of these subunits with tRNA and a short nascent polypeptide chain, were grown from polyethylene glycol in the presence of salts at low concentrations. Within experimental error, all these crystals are isomorphous, packed with monoclinic symmetry (C2) in unit cells of a = 300 A, b = 546 A, c = 377 (+/- 1%) A and beta = 112 degrees. Using synchrotron radiation at 85 to 100 K they diffract to 11 A resolution and can be irradiated for hours without disintegrating, so that a complete data set could be collected from a single crystal.     

Cleavage of synthetic peptides by purified poliovirus 3C proteinase

Synthetic peptides, 14-16 residues in length, were used as substrates for purified recombinant poliovirus proteinase 3C. The sequences of the substrates correspond to the sequences of authentic cleavage sites in the poliovirus polyprotein, all of which contain Gln-Gly at the scissile bond. Specificity of cleavages was demonstrated by analysis of 3C digests of synthetic peptides. Relative rate constants for the cleavages were derived by competition experiments. The rate constants roughly correlated with the estimated half-life of the homologous precursor proteins detected in poliovirus-infected cells. The peptide most resistant to cleavage corresponded to the 3C/3D junction, a site known to be cleaved very slowly by 3C in vivo. Substitution of threonine for alanine in P4 position of this peptide, however, resulted in significant cleavage. This observation supports the hypothesis that the residue in P4 position, in addition to the Gln-Gly in P1 and P1', respectively, contributes to substrate recognition. Ac-Gln-Gly-NH2 was not a substrate for 3C.