Evidence for the extranuclear localization of thymosins in thymus

A new radioimmunoassay has been developed for thymosin ₄ by generating rabbit polyclonal antibodies against the synthetic N-terminal peptide fragment 1–15 coupled to KLH. The synthetic analogue [Tyr¹²]-thymosin ₄ (1–15) was used as tracer. This radioimmunoassay, with a useful range of 10–1000 pmoles, showed cross-reactivity with the second homologous -thymosin of man and rat (thymosin ₁₀) but not of calf (thymosin ₉). This radioimmunoassay, together with an improved radioimmunoassay for the N-terminus of parathymosin , was employed for the measurement of the levels of thymosin ₄ and parathymosin 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 - and -thymosins.     

Adenyl cyclase activity in non-nucleated red blood cells: Evidence for its localization in the reticulocytes

Zusammenfassung Die durch Natriumfluorid und Isoproterenol stimulierbare Adenylcyclase-Aktivität in Erythrocyten-Schatten von 30–240 g schweren Ratten ist direkt proportional dem prozentualen Retikulocytengehalt des Blutes. Hinweise darauf, dass die Adenylcyclase-Aktivität kernloser Erythrocyten nahezu ausschliesslich in den Retikulocyten lokalisiert ist, konnten auch an menschlichem Blut erhalten werden.

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This work was supported by a grant from the Deutsche Forschungsgemeinschaft.

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The authors are indebted to Prof. Dr.Hj. Becker for support and helpful discussions.     

Monoamine oxidase activity in rat erythrocytes: Evidence for its localization in reticulocyte mitochondria

Summary During growth of young rats, monoamine oxidase activity in erythrocyte membrane preparations decreases more rapidly than reticulocyte concentrations in the respective blood samples. Since reticulocytes lose their mitochondria prior to the substantia reticulo-filamentosa, the non-linear correlation between monoamine oxidase activity and reticulocyte counts indicates that erythrocyte monoamine oxidase is located in reticulocyte mitochondria.This work was supported by a grant from the Deutsche Forschungsgemeinschaft.     

Ultrastructural autoradiographic study of blast cells in the mouse thymus. Interest for radioleukemia research.

Ultrastructural autoradiographic studies of mouse thymic blast cells after H3 Tdr injection show that their fine nuclear structure is related to their position in the cell cycle. The variations in the composition of the subcapsular blast cell population during radiation-induced leukemogenesis indicate kinetic changes in thymic lymphopoiesis, which are probably due to the oncogenic process.     

Telophase behavior of extranuclear chromatin and its bearing on telophase changes in chromosomes

Zusammenfassung Extranukleares Chromatin, in der Form azentrischer Fragmente oder Teile ungebrochener Chromosomen, welche aus der Kernregion von Heuschreken-Neuroblasten herausragen, unterliegt nicht gleichzeitig mit dem intranuklearen Chromatin den telophasischen Veränderungen. Der oder die für die Telophaseveranderungen vor allem verantwortlichen Faktoren scheinen in der Kernregion der Zelle lokalisiert zu sein. Es werden Belege dafür gegeben, dass die Chromosomen während der Telophase sich bedeutend vergrössern, und es wird die Ansicht vertreten, dass im Spindelmaterial, zum Teil wenigstens, die für die Schwellung der Chromosomen verantwortliche Substanz zu sehen ist.

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Work performed for Atomic Energy Commission under Contract No. W-7405-eng-26.     

Evidence for synergism in steroid hormone-receptor association.

A number of glucocorticoids stimulated oestradiol binding to liver cytosol receptor; oestradiol activated glucocorticoid receptor association at a time when it reversed triamcinolone mediated increase in liver glycogen synthesis.     

The role of the thymus in antinuclear autoimmunization

Résumé La thymectomie chez des souris CF1 âgées de 1 mois est suivie comme dans le cas de la thymectomie néonatale de l'apparition d'anticorps antinucléaires. Le transfert adoptif de l'autoimmunité antinucléaire apparu chez des animaux thymectomisés à la naissance n'est possible que si les animaux receveurs sont eux-mêmes thymectomisés. Ces constatations mettent en évidence un rôle possible de contrôle des réactions autoimmunes par le thymus.     

Evidence for dissociation of ferrihemoglobin by poly-L-lysine.

Circular dichroism and absorption spectra of ferrihemoglobin were shown to be altered upon binding with poly-L-lysine at alkaline pH. When ferrihemoglobin immobilized to Sepharose gel was treated with poly-L-lysine, hemoglobin subunits were released from the gel. These results suggest that ferrihemoglobin was dissociated into subunits by poly-L-lysine.     

Evidence for plasmidic localization of "beta-lactamase" gene in a Pseudomonas aeruginosa strain, highly resistant to carbenicillin]

Pseudomonas aeruginosa strain HL, isolated in Besan?on (France), shows a high level of resistance for carbenicillin, as proved in preliminary studies. In this paper, we report the transfer of carbenicillin resistance from Pseudomonas aeruginosa HL1 carrying helper plasmids to other strains of the same species. Comparative study of beta-lactamase activity in the HL1 strain and in the conjugated strains allows confirmation of the transfer of an R-factor from the HL1 strain: in all these strains, the beta-lactamase has the same pI (5.3) and the same Vmax (relative to benzylpenicillin) for ampicillin, carbenicillin and cephaloridin.     

Intracellular localization of calcitonin in the C cells of the rat.

Specific localization of C cells at the electron microscope level was achieved by an indirect immunoperoxidase technique. The hormone is present in the electron dense granules. The presence of granules apparently devoid of calcitonin was also detected.     

Ultrastructural localization of vanadium in the blood cells of Ascidiacea.

X-ray histospectrographic analysis at the scanning and transmission electron microscope (STEM) are made on the blood cells of Phallusia mamillata Cuvier and Ciona intestinalis, to study the 'direct' intracellular sites of accumulation of vanadium. The results show a clear accumulation of vanadium on the membrane and in the granules of vacuoles of amebocytes, signet ring cell, compartment cell and traces of metal in the 'vanadophores' of vanadocytes.     

Granules of Langerhans cells in the thymus contain gold

The granules of Langerhans cells in the thymus of the rat were subjected to X-ray microanalysis. It was established that gold is present in these morphological structures.     

Granules of langerhans cells in the thymus contain gold

Summary The granules of Langerhans cells in the thymus of the rat were subjected to X-ray microanalysis. It was established that gold is present in these morphological structures.     

Melatonin biosynthesis in the thymus of humans and rats

Melatonin is an indoleamine widely distributed in the evolution that shows a great functional versatility, playing an important role as a transmitter of photoperiodic information and exhibiting antioxidant, oncostatic, anti-aging and immunomodulatory properties. In vertebrates, this molecule is produced by the pineal gland and other extrapineal sites. The present study was carried out to investigate the presence of melatonin in thymus and the possibility of an endogenous melatonin synthesis in this organ, in which T cells are matured. In this work, we demonstrate in humans and rats that thymus contains melatonin, expresses the mRNAs encoding N-acetyltransferase and hydroxyindol-O-methyltransferase, the two key enzymes of the melatonin synthesis, and has this biosynthetic machinery activated. In addition, rat thymocytes cultured for 24 h exhibited high levels of melatonin. The results presented here suggest that human and rat thymuses are able to synthesize melatonin, which could have intracrine, autocrine and paracrine functions. Received 30 September 2006; received after revision 30 December 2006; accepted 15 February 2007     

Ultrastructural autoradiographic study of blast cells in the mouse thymus Interest for radioleukemia research

Summary Ultrastructural autoradiographic studies of mouse thymic blast cells after H3 Tdr injection show that their fine nuclear structure is related to their position in the cell cycle. The variations in the composition of the subcapsular blast cell population during radiation-induced leukemogenesis indicate kinetic changes in thymic lymphopoiesis, which are probably due to the oncogenic process.