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W Voelter

Publications and source records attributed to W Voelter.

At least 127 records · Page 7Linked to original sources
PubMed1992

Evidence for the extranuclear localization of thymosins in thymus.

A new radioimmunoassay has been developed for thymosin beta 4 by generating rabbit polyclonal antibodies against the synthetic N-terminal peptide fragment 1-15 coupled to KLH. The synthetic analogue [Tyr12]-thymosin beta 4 (1-15) was used as tracer. This radioimmunoassay, with a useful range of 10-1000 pmoles, showed cross-reactivity with the second homologous beta-thymosin of man and rat (thymosin beta 10) but not of calf (thymosin beta 9). This radioimmunoassay, together with an improved radioimmunoassay for the N-terminus of parathymosin alpha, was employed for the measurement of the levels of thymosin beta 4 and parathymosin alpha in nuclear and extranuclear extracts of calf thymus. The bulk of these polypeptides was found in the extranuclear material whereas only traces were observed in the nuclear environment, which indicates the extranuclear localisation of alpha- and beta-thymosins.

Animals↗
PubMed1992

The complete sequences of trout (Salmo gairdneri) thymosin beta 11 and its homologue thymosin beta 12.

Two forms of beta-thymosins, designated thymosin beta 11 and thymosin beta 12, were isolated from trout (Salmo gairdneri) spleen. This suggests that the presence of two beta-thymosins, previously thought to be a property of mammalian tissues only, is a more general phenomenon in vertebrate species. Both trout beta-thymosins were found to be N-terminally blocked by a group identified as acetyl by m.s. Automated protein sequencing of tryptic, thermolytic and Staphylococcus aureus in 41-residue V8 proteinase fragments revealed that one of the two beta-thymosins corresponds to the previously reported 41-residue-long sequence of thymosin beta 11 with two substitutions at positions 5 and 7, i.e. Asn instead of Asp, and Glu instead of Gln, whereas the other beta-thymosin, designated thymosin beta 12, was found to be a 42-residue polypeptide closely similar in sequence to thymosin beta 11, with five substitutions (i.e. at positions 5, 7, 10, 11 and 41, with Asp, Ala, Ser, Asn and Thr instead of Asn, Glu, Ala, Ser and Ser respectively) and one addition at position 42 (Ala). Comparison of the known six sequences of beta-thymosins together with the sequences reported here showed that the sequence similarity of the two beta-thymosins in trout (86%) is greater than that of the two beta-thymosins in mammalian species (74%) and that residues at 28 positions are identical in all beta-thymosins, the longer conserved segments located at positions 16-26 and 31-38.

Amino Acid Sequence↗
PubMed1992

A thymosin beta 4 ELISA using an antibody against the N terminal fragment thymosin beta 4 [1-14].

A thymosin beta 4 ELISA was developed in which thymosin beta 4, absorbed on microwells, competed with thymosin beta 4 in solution for the binding sites of an anti-thymosin beta 4 antibody. The antibody molecules finally immobilized on the microwells were detected using a goat anti-rabbit immunoglobulin/horseradish peroxidase conjugate in combination with the substrate 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt, and measuring the relevant optical density values. Anti-thymosin beta 4 antibodies were raised in rabbits against intact thymosin beta 4 as well as against selected fragments of the peptide, i.e., the N terminal fragments thymosin beta 4[1-14] and thymosin beta 4[1-11]. The antibody against thymosin beta 4[1-14] was used in the thymosin beta 4 ELISA, because it showed minimal cross-reactivity (0.1%) with the highly homologous peptide thymosin beta 9 as well as exhibiting the highest titre. The ELISA procedure developed, apart from showing a minimal cross-reaction with thymosin beta 9, was fast, easy to perform and exhibited good assay characteristics.

Animals↗
PubMed1991

Distribution of immunoreactive relaxin in the genital tract and in the mammary gland of non-pregnant women.

Relaxin was determined in healthy and pathological tissue samples from mammary gland, ovary, myometrium and cervix uteri of non-pregnant women. Relaxin could be detected in all groups of tissues examined. The highest values were found in healthy ovary, the lowest concentrations in the cervix, which is known as a target organ for relaxin activity during pregnancy. Mammary parenchyma showed the highest specific activity of all healthy tissues examined. The relaxin concentration in myoma tissue is significantly higher than in healthy myometrium.

Breast↗
PubMed1990

Involvement of thymosin beta 4 and endoproteinase Asp-N in the biosynthesis of the tetrapeptide AcSerAspLysPro a regulator of the hematopoietic system.

It is shown that AcSDKP a new regulator of the hematopoietic system can be generated from thymosin beta 4 by a one-step enzymatic cleavage in vitro and in vivo. AcSDKP and T beta 4 were both detected in bone marrow cells (BMC). Incubation of [3H]T beta 4 with either intact or lysed BMC led to the formation of [3H]AcSDKP whereas the labelled tetrapeptide was not degraded under these conditions. Model enzymatic degradation of T beta 4 carried out with bacterial enzymes suggests that a mammalian endoproteinase Asp-N might be involved in the formation of AcSDKP through the specific cleavage of the 4Pro-5 Asp peptide bond of T beta 4.

Amino Acid Sequence↗
PubMed1990

Solution conformation of thymosin beta 4: a nuclear magnetic resonance and simulated annealing study.

The conformation of the polypeptide thymosin beta 4 in solutions of 60% (v/v) trifluoroethanol-d3 and 50% (v/v) hexafluoroisopropyl-d2 alcohol in water is investigated by nuclear magnetic resonance (NMR) spectroscopy. Under these conditions thymosin beta 4 adopts an ordered structure. By use of a combination of two-dimensional NMR techniques, the 1H NMR spectrum of thymosin beta 4 is assigned. A set of 180 approximate interproton distance constraints is derived from nuclear Overhauser enhancement (NOE) measurements. These, together with 33 phi constraints obtained for JNH alpha coupling data and the 23 psi dihedral angles identified on the basis of the pattern of short-range NOEs, form the basis of a three-dimensional structure determination by dynamical simulated annealing. The calculations are carried out starting from three initial structures, an alpha-helix, an extended beta-strand, and a mixed alpha/beta structure. Ten independent structures are computed from each starting structure by using different random number seeds for the assignments of the initial velocities. All 30 calculated structures satisfy the experimental constraints, display very small deviations from idealized covalent geometry, and possess good nonbonded contacts. Analysis of the 30 converged structures indicates that there are two helical regions extending from residues 4-16 and from residues 30-40, which are well defined both in terms of atomic root mean square differences and backbone torsion angles. For the two helical regions individually the average backbone rms difference between all pairs of structures is approximately 2 A. The two helices exhibit typical amino acid preferences for specific locations at the ends of helices.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Immunohistochemical localization of thymosin beta 9 in bovine tissues.

Using an indirect fluorescent antibody technique with frozen sections, the localization of thymosin beta 9 was investigated for the first time in bovine thymus, spleen, lung, muscle and liver. The antibodies used have been raised against the N-terminal fragment 1-14 of thymosin beta 9 in order to minimize the cross-reactivity with thymosin beta 4 which was found to be also present in bovine tissues. The specific antibodies against thymosin beta 9 raised in our laboratory allowed us to localize this peptide in presence of the highly homologous and always accompanying thymosin beta 4 in different tissues. Although thymosin beta 9 was first isolated from calf thymus, it could be also detected in other bovine organs. The highest density of positive immunoreaction was found to be in spleen sections. In the muscle tissue a pronounced fluorescence intensity was present in the region of the sarcolemma.

Animals↗
PubMed1990

Acid-labile anchoring linkages for solid phase synthesis of C-terminal asparagine peptides using the Fmoc strategy.

Two acid-labile substituted benzylamine type anchoring linkages, 4-benzoxy-2,6-dimethoxybenzylamine and 2-benzoxy-4,6-dimethoxybenzylamine, for solid phase synthesis of peptide amides were prepared. The Na-9-fluorenylmethyloxycarbonyl (Fmoc) amino acids could be easily attached to the resins with DCC/HOBt (loading 0.5-0.6 mmol/g resin). After final removal of the Na-protecting groups, treatment with TFA (50-95%) yielded amino acid and peptide amides in high purity. As we could show for the synthesis of thymulin (FTS, pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn), these two resins with anchoring linkages are well suited for the synthesis of C-terminal Asn peptides using protected aspartic acid derivative as starting material.

Amino Acid Sequence↗
PubMed1990

Peptides related to the active fragment of "proline rich polypeptide", an immunoregulatory protein of the ovine colostrum. Spectroscopic and computer modeling studies.

The preferred solution conformation of the PRP-hexapeptide (Tyr-Val-Pro-Leu-Phe-Pro) and of some of its structural analogues was investigated by NMR-spectroscopy, spectrofluorimetry and computer simulation technic. It was found that the preferred conformation is characterized by cis'-conformation of Pro3 and the gamma-turn on the Leu4-residue: for Val2 and Phe5 a beta-structure seems to be privileged. In such a conformation Val2 and Leu4 residues occupy exactly the same positions in space as residues i and i + 3 in an alpha-helix. It suggests that the PRP-hexapeptide can interact with receptor protein inducing or stabilizing its helical conformation by "knobs into holes" packing.

Amino Acid Sequence↗
PubMed1989

MicroELISA method for the determination of thymosin beta 9 discriminating between thymosin beta 9 and the structurally closely related thymosin beta 4.

In order to obtain specific antibodies against thymosin beta 9 showing minimal cross-reactivity with the highly homologous peptide thymosin beta 4, the N-terminal fragment 1-14 of thymosin beta 9 was used for immunization. These antibodies have been tested in a competitive ELISA and show less than 1% cross-reactivity with thymosin beta 4. On the other hand, antibodies raised against the native thymosin beta 9 (1-14) cross-react 35% with thymosin beta 4. Specific antibodies against thymosin beta 9 are important for studying the concentration and localization of thymosin beta 9 in thymus and other bovine tissues because thymosin beta 9 is always accompanied by thymosin beta 4. Using N-terminal fragments of thymosin beta 4-like peptides may be a general approach for obtaining specific antibodies since this part of sequence is less conserved in thymosin beta 4-like peptides.

Amino Acid Sequence↗
PubMed1989

[Metabolic studies of 5-ethyl-2'-deoxyuridine with liver extract, liver cells and liver cell culture].

5-Ethyl-2'-deoxyuridine (EtUdR) was converted with rat liver extract, rat liver cells and rat liver cell cultures into its metabolites 5-ethyluracil and 5-(1-hydroxyethyl) uracil. The analytical identification of the metabolites as well as the investigation of the biotransformation process was performed by thin layer chromatography, autoradiography and high pressure liquid chromatography.

Animals↗
PubMed1988

Thymosin beta 4Xen: a new thymosin beta 4-like peptide in oocytes of Xenopus laevis.

Two new thymosin beta 4-like peptides have been detected in ovaries of Xenopus laevis and Rana esculenta. Previously, it was reported that thymosin beta 4 can be found in various species, from mammals to amphibians, e.g., in X. laevis [S. Erickson-Viitanen, S. Ruggieri, P. Natalini, and B.L. Horecker (1983) Arch. Biochem. Biophys. 221, 570-576]. However, oocytes and spleen from R. esculenta contain no thymosin beta 4 but a similar peptide without methionine. The peptide from R. esculenta elutes from a reversed-phase column about 5 min later than thymosin beta 4. The peptide from X. laevis, referred to as thymosin beta 4Xen, can hardly be distinguished from thymosin beta 4 by its retention time on HPLC, by amino acid analysis, its isoelectric point, or tryptic fingerprinting. Amino acid analyses of the tryptic fragments, however, have revealed that thymosin beta 4 and beta 4Xen are different. The amino acid sequence of thymosin beta 4Xen is reported. Thymosin beta 4 and beta 4Xen differ in the amino acid residues at positions 15, 40, and 41. At position 15 serine is replaced by alanine and at 41-42 the sequence is Thr-Ser instead of Ala-Gly. Depending on their size, defolliculated oocytes contain between 2.7 and 52.6 ng thymosin beta 4Xen which is comparable to the amount of histones in oocytes.

Amino Acid Sequence↗
PubMed1988

Immunoreactive relaxin in human cervico-vaginal secretion.

Relaxin was measured in cervico-vaginal secretion of non-pregnant women of reproductive age using the heterologous radioimmuno-assay for porcine relaxin. It was detected in about three-quarters of the samples collected. The mean value of the 529 samplers tested was 599 pg/ml. There was a slight trend to higher relaxin values during the second week of the menstrual cycle.

Adult↗
PubMed1988

Relaxin and human chorionic gonadotropin concentrations in blood serum during the first trimester of normal and pathological pregnancy.

Relaxin and human chorionic gonadotropin (HCG) were determined in the blood serum of women during normal and pathological pregnancy in the 1st trimester. In normal pregnancy, the hormones showed similar behavior in their secretion pattern up to the 7th week with continuously increasing concentrations. Thereafter different patterns in their secretion developed. In pathological pregnancy, both relaxin and HCG concentrations were significantly lower than in undisturbed pregnancy, following an almost parallel course without peaks.

Chorionic Gonadotropin↗
PubMed1988

Relaxin deficiency in the placenta as possible cause of cervical dystocia. A case report.

In a case of cervical dystocia which had to be delivered by caesarean section, the placenta was examined for relaxin content. The placenta was processed by acidic acetone extraction and separation of the raw extract on a carboxymethylcellulose column. The activity of relaxin was estimated by means of heterologous porcine radioimmunoassay. The elution profile of the placenta extract showed significant differences to that of the placenta in normal deliveries i.e. there was no evidence of typical protein peaks with relaxin activity. It is suggested that there is possibly a causal relationship between the lack of placental relaxin and the pathological behaviour of the cervix during delivery.

Adult↗
PubMed1987

The action of relaxin, fenoterol and etilefrine on uterine motility of the rat.

In uterine motility tests in virgin rats, the inhibitory action of the peptide hormone relaxin has been compared with the actions of fenoterol and etilefrine. At molecular levels, relaxin and fenoterol showed similar uterine inhibitory activity. Etilefrine was markedly less effective in inducing uterine relaxation. By pretreatment with propranolol, the inhibitory action of both fenoterol and etilefrine could be prevented but not the tocolytic effect of relaxin. Etilefrine, in higher doses, developed alpha-receptor activity as demonstrated by resumed uterine contractions. The doses required to induce beta 2- and alpha-activities differed by a factor of approximately 4,000.

Animals↗
PubMed1987

Dose response relationship of relaxin on the pubic ligament of the mouse.

In the present work, the dose-response relationship of highly purified porcine relaxin has been examined on broadening of the pubic ligament in mice. Using the method of Steinetz et al. with 7 days of oestriol priming, higher sensitivity of the pubic ligament was attained in mice with an original weight of 10 g than in those with a weight of 20 g. S-shaped curves were obtained; by increasing the relaxin doses after maximal effect had been reached a decreased action was observed. With presomen priming, a relaxin effect was established after only 2 days instead of the usual 8 days but the action was markedly less than in the Steinetz test.

Animals↗