Uridine enhances expression of the fragile X chromosome in human lymphocytes

Summary We have studied the effect of uridine on the expression of fragile X (fra[X]) in lymphocyte cultures established in the folate and thymidine deficient medium TC199. The results indicate that uridine enhances the expression of fra(X) and gives a higher mitotic rate. The excess of uridine during DNA synthesis might further promote the previously suggested cycle of misincorporation and removal of deoxyuridine monophosphate when the pool of deoxythymidine triphosphate is continuously depleted.     

Sexual differences in auditory sensitivity: mismatch of hearing threshold and call frequency in a tettigoniid (orthoptera,tettigoniidae: Zaprochilinae)

Summary Sexual dimorphism of the ear of an undescribed species of zaprochiline tettigoniid is described. The internal trachea, dedicated to hearing in other tettigoniids, is unmodified in the male but fully developed in the female. The external auditory spiracle is also lost in the male. In contrast, there is no difference between the sexes in the number of sensilla within the hearing organ. The male is 10 dB less sensitive than the female. The characteristic frequency of the hearing organ at 35 kHz does not match the carrier frequency of the male's call at 51 kHz. As a result of this mismatch the female is remarkably insensitive to the male's call (threshold at 75 dB SPL), and the male is even less sensitive (thresholds80 dB SPL). In nature this provides a maximum hearing range of the male of less than 50 cm.     

The plasminogen activator family from the salivary gland of the vampire bat Desmodus rotundus: cloning and expression

Complementary DNAs coding for four Desmodus rotundus salivary plasminogen activators (DSPAs) were isolated and characterized. The predicted amino acid sequences display structural features also found in tissue-type plasminogen activator. The largest forms (DSPA alpha 1 and -alpha 2) contain a signal peptide, a finger (F), an epidermal growth factor (EGF), a kringle, and a serine protease domain, whereas DSPA beta and -gamma lack the F and F-EGF domains, respectively. Additional differences between the four forms suggest that distinct genes code for the members of the DSPA family. Transfection of DSPA-encoding cDNAs, placed under the control of the simian virus 40 late promoter, into COS-1 cells resulted in the secretion of highly fibrin-dependent PAs.     

The malmö polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms

A mouse monoclonal antibody (MAB 9.9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism—Thr:Ala—at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148^thr) are designated Malmö A, and negative reactors (148^ala) are designated Malmö B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmö A in AB women is approximately half that of AA women, and “lyonization” is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over—including double crossing-over—appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ～50% of the AB women in the pool of Malmö A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmö epitope if the studies were limited to men.     

5'-Methylbenzimidazolyl-cobamides are the corrinoids from some sulfate-reducing and sulfur-metabolizing bacteria

The sulfate-reducing bacteria Desulfobacterium autotrophicum, Desulfobulbus propionicus and Archaeoglobus fulgidus (VC-16) and the sulfur-metabolizing archaebacteria Desulfurolobus ambivalens and Thermoplasma acidophilum were found to contain considerable amounts of corrinoids, that were isolated and crystallized in their Co beta-cyano form. In three other sulfur-metabolizing archaebacteria, Thermoproteus neutrophilus, Pyrodictium occultum and Staphylothermus marinus significant amounts of corrinoids were not detected under the isolation methods used. The samples from the three sulfate-reducers were identified with Co alpha-[alpha-(5'-methylbenzimidazolyl)]-Co beta-cyanocobamide. This corrinoid was also obtained from a 5-methylbenzimidazole-supplemented Propionibacterium fermentation and was structurally characterized by ultraviolet/visible, CD, fast-atom-bombardment MS, 1H-and 13C-NMR spectroscopy. Also the major corrinoid from T. acidophilum was (tentatively) analyzed as a 5'-methylbenzimidazolyl-cobamide, whereas the main corrinoid from D. ambivalens was indicated to be vitamin B12 (a 5',6'-dimethylbenzimidazolyl-cobamide). The 5'-methylbenzimidazolylcobamides are found here as the common corrins of some sulfate-reducing and sulfur-metabolizing bacteria. The structural diversity due to the differing nucleotide bases of the corrins examined here and in methanogenic and acetogenic bacteria appears not to correlate to the biological function(s) of the corrins, but rather to be determined by biosynthetic properties of these organisms under natural growth conditions.     

Spring development of a Chlamydomonas population in Lake Nimetön,a small humic forest lake in southern Finland

Biomass development and vertical distribution of a Chlamydomonas population in a small humic forest lake was followed by daily sampling in May-June, 1984. Chlamydomonas dominated the phytoplankton spring bloom, forming 71% of the maximum phytoplankton biomass on 18 May. In early May the outflow rate was high and during the 24 hour period when the maximum rate of surface runoff was recorded (8–9 May), 43% of the Chlamydomonas biomass was flushed out of the lake, which delayed the onset of biomass increase. When surface runoff had slowed down Chlamydomonas biomass started increasing and during wax of the population most cells were < 10 µm in diameter. Population maximum lasted for one day (18 May) and there-after Chlamydomonas biomass decreased towards the end of the study. During wane of the population most cells were > 10 µm in diameter.     

Regular and irregular divisions of Lepidoptera spermatocytes as related to the speed of meiotic prophase

Lepidoptera males bear two kinds of meiotic divisions. One is regular (eupyrene) and leads to nucleate, fertilizing spermatozoa. The other (apyrene) shows metaphase I chromosomes clumping together into irregular masses which later split forming daughter cells with unbalanced sets of chromosomes which are eventually extruded from the cells; hence, the spermatids develop into anucleate spermatozoa of unknown function. The apyrene divisions are induced by a haemolymph factor which becomes functional towards pupation. Using incorporation of tritiated thymidine at the premeiotic S-phase as a marker for timing, it was found that the prophase of the apyrene spermatocyte is shorter than that of the eupyrene spermatocyte. It is proposed that meiosis-specific proteins cannot be synthesized during the shortened apyrene prophase and that this is correlated with the irregular chromosome behaviour during the subsequent metaphase-telophase of these spermatocytes.     

Prostaglandin-E2 9-ketoreductase from human uterine decidua vera

Prostaglandin-E2 9-ketoreductase, the enzyme which catalyzes the reaction from prostaglandin E2 (PGE2) to prostaglandin F2 alpha (PGF2 alpha), has been purified 232-fold from human uterine decidua vera. The molecular mass of the enzyme, as estimated by fast protein liquid chromatography, was 29 kDa. Sodium dodecyl sulfate disc gel electrophoresis of the denatured enzyme revealed a molecular mass of 31 kDa. These data suggest that the enzyme consists of a single polypeptide chain. The rate equation of the enzyme reaction for two substrates was used for the determination of five kinetic constants. The equilibrium constant with respect to PGE2 was 83 microM, the Michaelis constant, Km, for PGE2 was 93 microM. For NADPH, the equilibrium constant was 1.0 microM and Km was 1.6 microM. The maximal velocity for the forward reaction was V1 = 217 pmol/min. The inhibition constants for the analgesic agents indomethacin and fentiazac were Ki = 850 microM and Ki = 450 microM and for the steroid progesterone Ki = 1.5 mM, respectively. Prostaglandin-E2 9-ketoreductase might be responsible for the control of the PGE2/PGF2 alpha ratio in human decidua vera. The enzyme, therefore, might be an important factor in the cascade of events leading to uterine contractions and parturition.     

Increase of circulating beta-endorphin-like immunoreactivity correlates with the change in feeling of pleasantness after running

Twenty-one male regular long distance runners participated in two 10 km runs one week apart. Their beta-endorphin-like immunoreactivity (beta-EIR) was assayed in plasma before and immediately after running. Mood was monitored by an adjective check list (Eigenschaftsw?rterliste, EWL) pre- and post-run. beta-EIR was significantly elevated post-run. Self-reliance and good mood scored higher after running. Both mood elevation and plasma beta-EIR increase showed a considerable individual variability but there was a significant correlation in the mean values of the two runs between individual beta-EIR increases (delta beta-EIR) and the changes of ratings in feeling of pleasantness (delta FP). High delta beta-EIR corresponded to positive mood change post-run.     

Enhanced response to Con A and production of TCGF by lymphocytes of obese strain (OS) chickens with spontaneous autoimmune thyroiditis

The mitogenic response to Con A and the production of T cell growth factor or interleukin 2 (IL 2) by splenic and peripheral blood lymphocytes of obese strain (OS) chickens with spontaneous autoimmune thyroiditis have been investigated. By using an optimized method with Con A-coated chicken erythrocytes (MRC), lymphocytes of OS chickens were found to exhibit significantly elevated mitogenic responses as compared with cells from either Normal White Leghorn chickens (NWL) or animals of the Cornell C-Strain (CS), from which the OS has originally been developed. This difference was observed throughout ontogeny up to 15 mo of age, and was associated with increased levels of IL 2 activity in the culture supernatants. The elevated responsiveness of OS T lymphocytes was also found to be manifested in the expression of receptors for IL 2, because Con A-stimulated lymphocytes of OS birds were significantly more effective than those from normal controls in absorbing IL 2 activity from conditioned media (CM) of stimulated spleen cells. High concentrations of CM were suppressive in IL 2 assays, signaling the presence of an inhibitory factor(s) in addition to IL 2. An additional indication for defective immunoregulation was that CM from OS lymphocyte cultures showed significantly less of this suppressive activity in comparison with CM of normal (NWL and CS) lymphocyte cultures. Finally, the spontaneous uptake of 125IUdR of embryonic and early post hatching OS spleen lymphocytes was consistently and significantly enhanced. This difference, however, in contrast to the one observed in Con A responses, was found to decrease with age. The data are discussed in view of the contradictory results concerning T cell functions reported for several autoimmune states in mammals.