Superoxide Radical-Mediated Alteration of Synaptosome Membrane Structure and High-Affinity γ-[14C]Aminobutyric Acid Uptake

Mouse cortical synaptosomal structure and function are altered when exposed to hypoxanthine/xanthine oxidase (HPX/XOD)-generated active oxygen/free radical species. The structure of both the synaptic vesicle and plasma membrane systems are altered by HPX/XOD treatment. The alteration of synaptic vesicle structure is exhibited by a significant increase in the cumulative length of nonsynaptic vesicle membrane per nerve terminal. With respect to the nerve terminal plasma membrane, the length of the perimeter of the synaptosome is increased as the membrane pulls away from portions of the terminal in blebs. The functional lesion generated by HPX/XOD treatment results in a reduction in selective high-affinity gamma-[14C]aminobutyric acid (GABA) uptake. Kinetic analysis of the reduction in high-affinity uptake reveals that the Vmax is significantly altered whereas the Km is not. Preincubation with specific active oxygen/free radical scavengers indicates that the super-oxide radical is directly involved. This radical, most probably in the protonated perhydroxyl form, initiates lipid peroxidative damage of the synaptosomal membrane systems. Low-affinity [14C]GABA transport is unaltered by the HPX/XOD treatment. The apparent ineffectiveness of free radical exposure on low-affinity [14C]GABA transport coupled with its effectiveness in reducing high-affinity transport supports the idea that two separate and different amino acid uptake systems exist in CNS tissue, with the high-affinity being more sensitive (lipid-dependent) and/or more energy-dependent (Na+,K+-ATPase) than the low-affinity system.     

Contribution of cardiogenic oscillations to gas exchange in constant-flow ventilation

The contribution of cardiogenic oscillations to gas exchange during constant-flow ventilation was examined in 11 dogs. With the use of two variations of cardiopulmonary bypass to maintain the systemic and pulmonary circulation, the influence of cardiogenic oscillations was removed by arresting the heart. Cardiac arrest by ventricular fibrillation was associated with a mean decrease in alveolar ventilation of 43% in five dogs on right and left heart bypass. However, successful defibrillation and return of the prearrest level of alveolar ventilation could not be achieved; thus we studied six dogs on left heart bypass. Alveolar ventilation decreased an average of 37% with cardiac arrest, and defibrillation resulted in a return of alveolar ventilation to 81% of the prearrest value. These results are consistent with previous predictions that cardiogenic oscillations are an important mechanism of gas transport during constant-flow ventilation.     

Modulation of the serotonin S2-receptor in brain after chronic lithium

In vivo effects of chronic lithium administration on dopaminergic and serotonergic receptor binding were studied in the striatum and cerebral cortex of the rat. [³H]Domperidone was used as the ligand for the dopaminergic receptor, and [³H]ketanserin for the serotonergic system. Long-term ingestion of lithium (2–3 months) resulted in high levels of lithium in the cerebral cortex and significantly higher potassium levels; the sodium content remained at normal levels. The kinetic constants (K _d andB _max) of [³H]domperidone binding sites measured in the striatum did not show any deviation from control values, but the receptor concentration (B _max) of [³H]ketanserin binding sites was significantly reduced in the cerebral cortex of lithium-treated rats. The apparent dissociation constant (K _d) was not changed. The results indicate that the serotonergic component of the [³H]spiperone binding site, which we had previously found to be affected by chronic lithium treatment and which was shown by Peroutka and Snyder (1) to be the 5-HT₂ receptor, is selectively affected by lithium.Special Issue dedicated to Prof. Eduardo De Robertis.     

Zur Ethologie von Putzsymbiosen einheimischer Süßwasserfische im natürlichen Biotop

Zusammenfassung Erstmals konnten Putzsymbiosen zwischen Süßwasserfischen im natürlichen Biotop beobachtet werden. Die sowohl intra-als auch interspezifischen fakultativen Symbiosen wurden bei Bitterling (Rhodeus sericeus amarus), Laube (Alburnus alburnus), Schleie (Tica tinca), sowie bei juvenilen Rotaugen (Rutilus rutilus), Rotfedern (Scardinius erythrophthalmus) und Flußbarschen (Perca fluviatilis) festgestellt. Bei Übertragung der Putzstimmung im Schwarmverband kann ein Putzen im Kollektiv auftreten, wo jeder jeden putzt bzw. dazu auffordert. Das Ausgangsverhalten zum Geputztwerden ist die Einstellung der Lokomotion (Putzstarre), wobei die beobachteten Süßwasserfische im Gegensatz zu marinen Fischen selbst in der Aufforderungsstellung kompensatorische Flossenbewegungen durchführen. Diese einleitende Reglosigkeit kann bereits Putzen durch den Partner auslösen, dessen Bereitschaft mit zunehmender Schrägstellung des Putzkunden gesteigert wird. Das Kopfabwärtsstehen erfolgt durch passives Absinken des Körpervorderteiles, woraus sich stammesgeschichtlich das aktive Schräg-bis Kopfstehen als Aufforderungssignal entwickelt haben dürfte (Laube, Rotfeder, Rotauge). Wahrscheinlich kann die steile Aufforderungsstellung durch Selbstdressur und durch Nachahmen individuell gelernt werden. Fische, die auffordernde Partner anschwimmen, nehmen bei diesen häufig statt zu putzen ebenfalls die Aufforderungsstellung ein; entweder durch Stimmungsübertragung, oder das Anschwimmen erfolgte bereits in der Erwartung, dort ebenfalls geputzt zu werden. Selten treten Kopfzucken (Alburnus) oder Körperrütteln (Scardinius) als wahrscheinlich zusätzliche Aufforderungssignale auf. Attrappenversuche zeigen, daß alle Details des auffordernden Fisches realisiert sein müssen, um als Aufforderung zu wirken, was auf einen gelerten Auslösemechanismus schließen läßt. Die juvenilen Flußbarsche zeigen als Aufforderung neben leichter Schrägstellung ein Zeitlupen-Scheuern vor dem Partner im freien Wasser, was aus dem Verhalten des Normalscheuerns der selbständigen Körperreinigung abzuleiten ist, wobei der Bitterling Zwischenstufen aufweist (Schein-Scheuern).Ein weit ausholender Schwansschlag, möglicherweise ein ÜbersprungverhaIten, löst die Spannung der Putzstarre. Diese überbetonte Intentionsbewegung zum Schwimmstart läßt noch keinen Ansatz zur Signalbildung erkennen. Zu denken wäre an das Körperschütteln mancher Putzkunden tropischer Meere, um die spezialisierten Putzerfische fortzuschicken. Diese fehlen jedoch im einheimischen Süßwasser, wodurch auch das Überwiegen der Putzaufforderungen gegenüber der Putztätigkeit verständlich wird.

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Summary Cleaning symbioses are described for the first time between fresh water fishes in their natural habitat. The symbioses are only facultative and were observed intra-and intorspecifically between members of the species Rhodeus amarus, Alburnus alburnus, Tinca, tinca and juvenile Rutilus rutilus, Scardinius erythrophthalmus and Perca fluviatilis.When the motivation to become cleaned is transmitted within a school of fish, mutual cleaning and inviting each other is common. The first stage in cleaning behaviour is cessation of movement and maintenance of a rigid posture which in these species of fish—contrary to marine species—is accompanied by compensatory fin movements.The more vertical the motionless posture of a fish the more active is the cleaning response of the partner. The vertical position is attained by passive sliding down of the head part. This form of display may be learned individually by imitation and (or) by trial and error.Fish approaching an inviting partner very often assume the invitation posture themselves instead of starting with the cleaning activity. This may be explained by transmission of the mood of invitation or because the invitation display raises the expectation in the approaching fish to become cleaned. Occasionally the invitation display is enhanced by head jerks (in Alburnus) or by body wriggling (in Scardinius).Tests with dummies prove that all details of the invitation pattern have to be fulfilled in order to make it acceptable as such by the partner. This points towards a learned releasing mechanism. Juveniles of Perca fluviatilis, besides assuming a slightly oblique posture, also show an additional feature of the invitation display by slow rubbing motions in front of swimming partners. This sslow motion rubbing may have developed from the normal cleaning behaviour which consists in rubbing the body against the ground. Intermediate stages between these two functions of rubbing motions are shown by Rhodeus amarus (apparent rubbing).The motionless posture of invitation is broken by a large beating of the tail, which may be a displacement activity. This exaggerated intention movement has, however, not yet evolved into a social signal, comparable, for example, to the body shaking of some marine fish by which these induce their cleaners to leave. There are no specialized cleaning fishes in fresh water which explains the dominance of invitation dispays over cleaning activities.

     

Amino acid uptake in the peripheral nerve of the rat

When rat sciatic nerves were incubated with C¹⁴l-lysine, l- or d-glutamate, or d-l γ-aminoisobutyrate, the labeled compounds penetrated the nerve, and the level of lysine and leucine after 1 hr was higher in the nerve than in the medium. The level increased with time, and at 24 hr glutamate levels also were higher in the nerve than in the medium. Lowering the temperature strongly inhibited uptake, while other conditions such as absence of glucose, absence of sodium, or the presence of cyanide inhibited uptake by nerve less than uptake by brain slices. The uptake against a concentration gradient, and inhibitions of this uptake by metabolic inhibitors and by structural analogs, were interpreted as showing the presence of transport processes for amino acids in peripheral nerves with characteristics similar to such transport processes in the central nervous system.     

Formation of an animal virus within a bacterium

Conclusions Incubation of competent cells ofB. subtilis with a DNA-like subviral entity from vaccinia virus leads to the formation of complete vaccinia virus in the bacteria. The significance of this finding in regard to the concept of a universal genetic code is discussed.With 2 Figures in the TextA preliminary report of these results was presented at the XI. International Congress of Genetics in The Hague, September, 1963.Habilitandenstipendiat 1962/63 of Deutsche Forschungsgemeinschaft.     

Ferritin H gene polymorphism in idiopathic hemochromatosis

Summary We have analysed karyotypes and DNA from three patients with aniridia (congenital absence of irises) and Wilms' tumour. All three had constitutional deletions from the short arm of chromosome 11. The minimum region of overlap of the deletion involves a small region of band 11p13 presumed to contain the genetic loci responsible for both phenotypic abnormalities. Using cells from these patients, somatic cell hybrids with transformed mouse cells have been prepared. Individual subclones retaining either the deletion-11 chromosome or the normal chromosome 11, in addition to a variety of other human chromosomes, have been identified. The relative position of these breakpoints have been determined and the panel of hybrids has been used to map randomly-isolated 11p13 DNA sequences. The characterisation of these deletions has provided a useful panel of hybrids for random mapping strategies designed to identify the Wilms' and aniridia genes.     

Maternal age does not affect tetrahydrocannabinol's in utero actions in rats

The potential contribution of maternal age to tetrahydrocannabinol's (THC) in utero effects in rats was studied. Pregnant animals were intubated with 25, 10 or 0 mg/kg of THC from gestation day six to parturition. Animals in the 10 and 0 mg/kg groups were pair fed to those given the 25 mg/kg dose. Each series of doses was administered to females three, four or six months of age. THC lowered maternal weight gain and weights of offspring at birth and at 21 days of age, but did not affect litter size, spontaneous alternation or passive avoidance learning in offspring. Increased maternal age was associated with smaller litter size and lower birth weight and weight at 21 days, but did not interact significantly with THC.     

Thievery,home ranges,and nestmate recognition inEctatomma ruidum

Summary Thievery of food items among colonies of a ponerine ant,Ectatomma ruidum was common; nonnestmates in colonies or near the colony entrances receive incoming food items and carry them to their own colony. In our study area 7 of 10 colonies were victimized by thief ants. Colonies have discrete home ranges and home range size is correlated with the number of workers in the colony. Worker ants discriminate nestmates from non-nestmates when non-nestmates are presented at colony entrances, but individuals from different colonies were not observed to engage in agonistic interactions away from nest entrances. Non-nestmates gain entrance to colonies when the entrance is unguarded. Many instances of non-nestmates being removed from colonies by residents were observed. The costs and benefits of theft under these circumstances are considered.