The co-ordination between respiration and wing beats in birds

Summary Investigations in 10 species showed that respiration of birds in flight is usually co-ordinated with wing beats, but the co-ordination is not obligatory. Respiration synchronous with wing beats (11 co-ordination) was found only in pigeons and crows, the other species exhibited one of 11 other types of co-ordination. Quails, ducks and pheasants, birds with relatively high wing beat frequencies (with relatively small wings) showed a 51 co-ordination. Within species, and even during a flight the type of co-ordination changed, and simultaneously there were sudden changes in the respiration frequency. For the most part, the beginning of inspiration was linked with the (end of) upstroke and the beginning of expiration with the end of downstroke.Issued as N.R.C.C. No. 11095Dedicated to Prof. Dr. Erwin Stresemann at his 80. birthday.We are grateful to Dr. D. Jensen for enabling the work on the gulls at McMaster University in Hamilton. We also wish to thank B. A. Mackenzie and R. Charbonneau for the skillful assistance in all experiments.     

New data on the toxic and radioprotective effect of cysteine onEscherichia coli 15 T- cells

Summary Exponential phase cultures ofE. coli 15 T^- cells growing on glucosemineral medium were supplemented with 2 mM l-cysteine-HCl. The optical density, acid soluble SH (AS-SH) as well as the DNA, RNA, and protein synthesis of the cultures were examined during this treatment and after return to normal growth conditions. Similarly, the survival of cells irradiated by a standard X-ray dose in cysteine-free buffer was measured.The development of radioresistance during the cysteine treatment as well as the loss of this acquired radioresistance after return to normal growth conditions could be divided into two phases: a) an instantaneous and b) a slow change of radioresistance. Phase a seems to be related to the changes occurring in the AS-SH content of the bacteria, while phase b is apparently dependent on the alterations in the synthesis of macromolecules.This work was partly presented at the 6th Annual Meeting of the European Society for Radiation Biology, Interlaken 1968.     

Studies in lipid histochemistry

Summary It was shown by experiments with staining reactions performed in situ in blood smears of adults and children, in sections prepared by various procedures, in spot tests, and by chromatographic examination of extracted lipids that haemoglobin is responsible entirely for the staining of red blood cells in the acid haematein test and for the greater part for the staining in the OTAN reaction. The acid haematein test is from the point of view of lipid histochemistry neither specific nor sensitive. On the other hand the OTAN reaction is sensitive although it is not specific. It is concluded that the extraction test with chloroform-methanol must always be performed when the lipidic nature of the demonstrated substance(s) is to be proved unequivocally and that the non-lipidic nature of the residual staining must be always considered.     

PASSAGE OF 5-HYDROXYTRYPTAMINE THROUGH THE BLOOD-BRAIN BARRIER, ITS METABOLISM IN THE BRAIN AND ELIMINATION OF 5-HYDROXYINDO-LEACETIC ACID FROM THE BRAIN TISSUE

Abstract— 5-HT was injected intravenously in rats (10 mg/kg) and a marked increase in brain 5-HT and 5-HIAA was observed. For the first 10 min after injection the penetration of 5-HT into the brain and formation of 5-HIAA is evident. After 10 min degradation of exogenous 5-HT and elimination of 5-HIAA are prominent. Metabolism of exogenous 5-HT in the brain is very fast (half-life between 5 and 10 min; completely metabolized in approximately 80 min). The importance of these results in explaining the permeability of blood-brain barrier to 5-HT is discussed. Experiments on brain slices show that 5-HT is more readily metabolized in brain tissue than eliminated into incubation medium. In contrast, 5-HIAA very easily leaves brain tissue.     

Reaction of β-propiolactone with amino acids and its specificity for methionine

1. The reactions of beta-propiolactone with amino acids were investigated under various conditions of pH and temperature to find those under which the reagent acted with specificity. 2. At pH9.0 and 22 degrees , after 15min. of reaction, at least 85% of each amino acid had reacted, methionine and cystine being the most reactive. 3. At pH7.0 and 22 degrees most amino acids reacted; methionine, cystine and histidine reacted almost entirely, and proline and lysine to a significantly smaller extent. 4. At pH3.0 and 22 degrees further specificity was obtained; methionine and cystine were the only reactive amino acids. 5. Reaction at pH3.0 and 0 degrees was specific for methionine; it was the only amino acid modified even after 145hr. of reaction.