Stress induced biosynthesis of a 31 kd-glycoprotein in goldfish brain.

The de novo protein synthesis in goldfish brain has been studied under defined stress conditions and after training in an active swimming task. One- and two-dimensional gel electrophoresis of the brain proteins previously labelled in vivo with 35S-methionine indicated that the synthesis of one distinct protein increases after stress but not after successful training. This protein is a glycoprotein with an apparent molecular weight of 31 kd and an isoelectric point of pH 5. It is discussed that the protein may be the ACTH precursor "pro-opiomelanocortin".

Influence of isolation stress and inhibited protein biosynthesis on learning and memory in goldfish.

Goldfish, Carassius auratus auratus L. (Pisces, Cyprinidae), were trained by different kinds of training procedures under the influence of cycloheximide or puromycin, two inhibitors of the protein biosynthesis. After active avoidance training in a shuttle box an apparent amnesia was found only when the fish were exposed to a one day lasting isolation stress prior to training. If the animals were accustomed to isolation over a period of 20 days the inhibitors did not affect memory formation. After learning by positive reinforcement (food rewarded color discrimination) in groups under stress-free conditions, neither learning nor memory formation were impaired in spite of the presence of cycloheximide. It is suggested that the amnestic effect of the inhibitors is caused by isolation treatment. Lack of the additional stress, however, leads to memory formation.

[Temperature dependence of courtship in male guppies, Poecilia reticulata Peters (Pisces, Cyprinidae)]. / Zur Temperaturabhängigkeit der Balz männlicher Guppys, Poecilia reticulata Peters (Pisces, Cyprinidae).

In poikilothermal animals, modes of behaviour as well as other physiological functions are dependent on the environmental temperature. Individual adaptation can decrease or cancel out this dependency. In experiments involving abrupt and slow temperature changes, we were able to prove temperature compensations and stress effects in the courting behaviour of the male Poecilia reticulata.

[Ecological imprinting and protein biosynthesis. Experiments with Drosophila melanogaster Meigen].

According to the "host selection principle", butterflies and other herbivorous insects preferentially lay their eggs on those plant races that they fed on when young. This is also true for karpophagic and parasitic insects. The selection of specific chemical conditions could be either inherited or acquired. If learned information determines host selection, we have a case of imprinting, as a) reception and use of the information are not simultaneous, b) there is no reward. In experiments with Drosophila melanogaster we marked the egg deposition medium with ethanol, acetic acid, peppermint oil, or benzaldehyd. The flies spontaneously prefer mediums with ethanol and acetic acid, and reject peppermint oil and benzaldehyd. If they are reared in one of these media, the preference for it is increased, or the rejection rate lowered. Rearing with actinomycin C neutralizes the effect of the other markers. It is concluded that actinomycin C blocks imprinting on the egg deposition substrate in Drosophila melanogaster.

[On the effect of some inhibitors of proteinbiosynthesis on activity and learning behavior of goldfish (Carassius auratus auratus L)]. / Uber die Wirkung einiger Inhibitoren der Protein-Biosynthese auf Aktivität und Lernverhalten beim Goldfisch (Carassius auratus auratus L)

Concerning the problems of learning and memory there is a distinction of a short term memory (STM) and a long term memory (LTM). It is supposed that the STM is an electrical phenomenon, whereas the LTM depends on material changes. The assumed materials are RNA, proteins, lipids, amines etc, and the primary carrier of the information is DNA. But there is a discrepancy: learning-specificity is based on environmental changes, but not the structure of DNA. For the investigation of this, we trained goldfish in a shock-free task to take food from coloured cups under the influence of inhibitors of the proteinbiosynthesis. There was no inhibition on memory-processes in our experiments.