Histochemical changes in the developing abscission layer in fruits of Prunus cerasus L.

Summary Abscission layer formation in the sour cherry (Prunus cerasus L.) during fruit maturation occurred in the transition zone between the fruit and the pedicel. The abscission layer, consisting of 5–8 rows of cells, was first identified by its low affinity for haematoxylin. The walls of cells in the abscission layer contained less total polysaccharides than adjacent cells. The pectins were degraded and the cellulose was partially broken down resulting in cell separation. The Ca level in the abscission zone decreased and Ca and Mg were lost from the walls of cells in the layer during abscission. After the abscission layer formed, cells associated with the layer had a lower capacity to bind ⁴⁵Ca than cells distal or proximal to the layer.Michigan Agricultural Experiment Station Journal Article No. 4607     

Formation of mitochondria in Boderia (Protozoa: Foraminiferida)

Summary Approximately 25 per cent of the mitochondria in one day old, rapidly growing, schizonts of Boderia vary considerably in their morphology from the consistently spherical organelles present in adult animals. Mitochondrial biogenesis by division is indicated and illustrated. The internal reorganisation of the mitochondrion which occurs prior to fission has not been reported previously for this organelle.     

Autoradiographische Untersuchungen zur funktionellen und pathologischen Kernschwellung in der Rattenleber nach Fütterung von Thioacetamid

Summary In the liver parenchyma of rats a markedly increase of the nuclear volume occurs after the application of thioacetamide. According to autoradiographic and morphological criterions this nuclear enlargement can be separated into a functional and a pathological swelling. In case of the functional swelling the rate of incorporation for H³-phenylalanine and H³-cytidine in the karyoplasm — as a measurement for protein and ribonucleic acid metabolism — is proportional to the nuclear volume. But in case of the pathological swelling the incorporation of these precursors is very much lower. In the functional swollen as well as in normal nuclei the volumetrical nucleolus/karyoplasm ratio can serve as an expression of the synthetic activity of both nuclear components. Yet this relation does not exist in pathological swollen nuclei. Therefore the functional swelling of the nucleus in comparison with the normal synthetic activities of the nucleus (karyoplasm + nucleolus) is an increased stage of function with completely preserved nuclear productivity. The pathological swelling however is a decreased state of function with a decompensated nuclear capacity.

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Die autoradiographischen Arbeiten wurden im Institut für Medizinische Isotopenforschung der Universität Köln (Leiter: Prof. Dr. W. Maurer) durchgeführt, für die Synthese der tritiierten Aminosäure danken wir Herrn Dr. Dr. K. Hempel.

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Die Arbeit lag 1963 der Medizinischen Fakultät der Universität Würzburg als Teil einer Habilitationsschrift vor. Sie wurde durch Mittel des Bundesministeriums für Wissenschaftliche Forschung ermöglicht.     

Une oasis aquatique à faune relique dans la Plaine du Danube inférieur

Résumé Etude d'un complexe de sources, situé dans la Plaine du Danube Inférieur (= Plaine Roumaine ou Plains de Valachie), à 100 m d'alt. environ. La station se caractérise par un complexe de facteurs uniques dans ce coin de (Europe: abondance de l'eau phréatique froide sortant à jour sur une surface restreinte, protection efficace grâce à une saulaie compacte, variété des substrats et abondance des sources trophiques. Ces éléments rendent possible l'existence d'une faune relique, comprenant rotifères, tardigrades, coléoptères, trichoptères, hydracariens, etc., espèces ayant ici leur seule station de la Plaine Roumaine. Les espèces qu'on signale dans le travail sont soit formes de montagne, soit à aréal septentrional ou septentrional-occidental, soit, enfin, caractéristiques pour les tourbières d'altitude, souvent même pour les tourbières acides à Sphagnum. On considère la faune du complexe de Corbii Ciungi comme un rests remarquable de la faune aquatique ayant peuplé la Plaine Roumaine antérieurement à la mise en friche sauvage des forêts et à l'extension impétueuse de l'agriculture, phénomènes ayant radicalement transformé ce territoire.     

Influence of lung volume on activities of branches of the recurrent laryngeal nerve

To investigate the influence of inspiratory lung inflation on the respiratory activities of laryngeal motor nerves, vagally intact decerebrate paralyzed cats were ventilated by a servorespirator in accordance with their own phrenic nerve activity. Records were made of the activities of the phrenic nerve, the superior laryngeal nerve (SLN), the recurrent laryngeal nerve (RLN), and the intralaryngeal branches of the RLN serving the thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles. Neural activities were assessed in the steady state at different end-tidal O2 and CO2 concentrations. Transient responses to withholding inspiratory lung inflation and to preventing expiratory lung emptying were also studied. Hypercapnia and hypoxia increased the inspiratory activities of the phrenic nerve, SLN, RLN, and its PCA branch. TA inspiratory activity was not changed. Expiratory activities of RLN, PCA, and TA were all increased in hypoxia. When lung inflation was withheld, neural inspiratory duration and the inspiratory activities of all nerves increased. The subsequent period of neural expiration was marked by an exaggerated burst of activity by the TA branch of the RLN. TA expiratory activity was also sharply increased after inspiratory efforts that were reflexly delayed by the prevention of lung emptying. TA activity in expiration was enhanced after vagotomy and was usually more prominent than when lung inflation was withheld before vagal section. The results demonstrate the importance and complexity of the influence of vagal afferents on laryngeal motor activity.     

Respiratory activities of intralaryngeal branches of the recurrent laryngeal nerve

To distinguish experimentally between motor nerve activity destined for vocal cord abductor muscles and that bound for muscles that adduct the cords, we recorded efferent activities of intralaryngeal branches of the recurrent laryngeal nerve (RLN) in decerebrate, vagotomized, paralyzed, ventilated cats. Activities of the whole RLN and phrenic nerve were also recorded. Nerve activities were assessed at several steady-state end-tidal O2 and CO2 concentrations. The nerve to the thyroarytenoid (TA) muscle, a vocal cord adductor, was only slightly active under base-line (normocapnic, hyperoxic) conditions but in most cats developed strong activity during expiration in hypocapnia or hypoxia. In severe hypocapnia, phasic expiratory TA activity persisted even during phrenic apnea, indicating continuing activity of the respiratory rhythm generator. The nerve to the posterior cricoarytenoid (PCA) muscle, the vocal cord abductor, was always active in inspiration but often showed expiratory activity as well. This expiratory activity was usually enhanced by hypercapnia and often inhibited by hypoxia. The results are consistent with previous electromyographic findings and emphasize the importance of distinguishing abductor from adductor activity in studies of laryngeal control.