Disruption of imprinting by memory inhibitors

Several amnestic drugs were administered intracranially to day-old chicks at selected times around a 10-min exposure to an imprinting stimulus. The drugs used were monosodium glutamate, ouabain, cycloheximide and amino-iso-butyrate. The chicks were tested for 10 min in the same apparatus two days later, and the time spent following the stimulu was recorded., The index of memory retention was the difference between the time spent following on test and the time spent following on the initial exposure. When compared with saline-injected control, glutamate administered 5 min before the beginning of the initial exposure was effective in producing a reduction in following times and hence amnesia. Ouabian was effective when injeced before the beginning and immediately after the end of the initial exposure; while cycloheximide was effective when administered as late as 5 min after the initial exposure. The effective times of administration for the drugs to produce a reduction in following times were similar to that observed for amnesia in passive avoidance memory tasks. The increase in following shown by the control chicks was not a developmental effect due to the increae in age on test. Experiments involving a choice of stimuli on test support the invovement of a memoryrelated phenomenon in these experiments.     

Does the neurotropic action of adrenocorticotrophic hormone involve a lipolytic step?

The stimulatory effect of adrenocorticotrophic hormone (ACTH)-related synthetic peptides on the hydrolysis of emulsified trioleoylglycerol by a rat brain lipase was studied. The ACTH effect was related to the net positive charge associated with the basic amino acid residues at position 15-18 in the ACTH sequence, as well as to the presence of the NH2-terminal amino acid residues at position 1-2. The ACTH effect on lipolysis was markedly reduced when lipids were partially removed from the enzyme preparation by extraction with chloroform/acetone. Full restoration of the stimulatory effect was obtained upon addition of phosphatidylcholine (2 mg/ml) to the lipolytic medium. Striking similarities between the structure-activity pattern for the stimulatory effect of ACTH on brain lipase and that described for the receptor-mediated actions of ACTH on adrenal and fat cells suggest that the ACTH effect might involve recognition of a binding site associated with the brain enzyme. Complete log concentration response curves obtained with four ACTH analogs may also be regarded as simulating hormone-receptor interaction. These findings are discussed in relation to the possibility that ACTH may have a neurohormonal role via lipase-catalyzed changes in the lipid matrix of membranes.     

In vitro translation of messenger ribonucleic acid from sporulating and nonsporulating strains of Bacillus subtilis.

An Escherichia coli translation system supplemented with ribonucleic acid from sporulating Bacillus subtilis produces unique polypeptides which are missing among translation products of ribonucleic acid from six early sporulation mutants.     

Isozyme shift in cultured fetal human hepatocytes: a study of pyruvate kinase and phosphofructokinase

Hepatocytes from a 4-month old fetus were cultured for 15 days. We found that fetal hepatocytes contained some R₁ (precursor) form of L-type pyruvate kinase. Culture was associated with a considerable increase of the M₂-type pyruvate kinase activity, but some L-type enzyme could be detected even after 10 days.Isozyme shift of phosphofructokinase seemed to be a progressive rather low phenomenon. Fetal hepatocytes showed an increase of the F-type form and a disappearance of the M-type form during culture. However, by day 10, the L-type enzyme remained predominant; this is in striking contrast with the findings reported on cultured fibroblasts.From these results, pyruvate kinase can be considered as a “strong” marker of cell differentiation, while phosphofructokinase is rather a “weak” marker.     

Effect of mouse genotype on interferon production

Upon induction with Newcastle disease virus, peritoneal macrophages derived from C57BL/6 mice produced ten times as much interferon as macrophages derived from BALB/c mice. This suggested that the alleles of theIf-1 locus are expressed in vitro by these cells. Further evidence for this was obtained by studying interferon production by peritoneal macrophages derived from seven recombinant inbred and one congenic line: in each case there was complete correlation between in vivo and in vitro phenotype: macrophages fromIf-1^l mice were low producers in vitro, and macrophages fromIf-1 ^h mice were high producers in vitro.     

Increased brain myo-inositol 1-phosphate in lithium-treated rats

Lithium was found to produce a marked elevation in the levels of $\text{myo}$-inositol 1-phosphate in the cerebral cortex of treated rats. This effect was completely inhibited by atropine. A 40% reduction in the levels of $\text{myo}$-inositol 1-phosphate was observed when atropine was given alone.     

Das Futterwahlverhalten des Rehes in einem voralpinen Revier

European Journal of Wildlife Research - Von April bis Juli 1972 wurden im voralpinen Revier Grabs Ost Beobachtungen zum Futterwahlverhalten des Rehes ausgeführt. Die Rehe wurden beim Äsen...