[Antibacterial peptides isolated from the urine of healthy adults]. / Antibakteriálne peptidy izolované z mocu zdravých l'udí.

Gel chromatography on Sephadex G-25, DEAE Sephadex A-25 and electrophoresis were used for isolation of two peptides from urine of healthy adults. Isolated peptides exhibited a higher antibacterial activity than antibiotics penicillin and tetracycline. The inhibitory zone of these peptides is similar to that of ampicillin. Chemical analysis of the isolated peptides revealed that one is composed of 5 and the other of 7 amino acids. In both peptides was the concentration of glycine the highest from all amino acids. the highest. (Tab. 1, Fig. 4, Ref. 22.)

[The effect of ethanol on the occurrence of peptides with antibacterial effects in the rat myocardium]]. / Vplyv etanolu na výskyt antibakteriálne úcinkujúcich peptidov myokardu potkanov.

The effect of 7% ethanol on the peptide content in the myocardium was studied during prolonged exposition. The protein-free extract from the myocardium of controls as well as experimental groups following 1-8 weeks ethanol administration contained peptides with antibacterial activity. Long-term ethanol administration resulted in changes in physico-chemical properties of peptides both compared with controls and also among the experimental groups mutually. The changes were manifested by differences in the elution profiles following gel chromatography and RF values after electrophoresis or by different amino acid composition. The results are compared with the influence of peptides on the growth of bacterial cultures S. aureus. Ethanol administration induced diminution of the diameter of the inhibitory zones. This effect was most marked in the group fed with ethanol for 3 and 8 weeks. (Fig. 5, Ref. 17.)

[Effect of chlortetracycline on the peptide spectrum of rat serum]. / Einfluss von Chloretrazyklin auf das Peptidspektrum im Rattenserum.

Application of chlortetracycline in rats resulted in the occurence of certain peptides in the blood-serum, which could not be detected in the serum of an untreated control group. These results were obtained by means of high voltage electrophoresis and paper electrophoresis of the serum of rats which was analyzed 1,3, and 13 hours respectively after a single dose of 50 mg chlortetracycline per 100 g body weight in comparison to an untreated control group. The new peptides could be found in the slight alkaline range 1 and 3 hours after application of chlortetracycline and in the strong acidic area of the electrochromatogram 13 hours thereafter. A more detailed investigation of the new peptides could demonstrate that the number of the following amino acids was reduced in the peptide chains after chlortetracycline: leucine, valine, serine, arginine, and lysine. On the other hand, amino acids, such as citrulline, sarcosine, alpha-aminobutyric acid, and ornithine, could be found which are normally not present in proteins.

[Effect of the prolonged administration of chlortetracycline on the content of free amino acids and low-molecular peptides in the blood serum of rats]. / Vliianie prodolzhitel'nogo vvedeniia khlortetratsikilina na soderzhanie svobodnykh aminokislot i nizkomolekuliarnykh peptidov v syvorotke krovi krys

Five individual ninhydrin positive fractions were found in the blood serum of rats in the control group with the help of high voltage electrophoresis in combination with preparative high voltage electrophoresis and paper chromatography. An analogous analysis of the blood serum of the test animals treated with 50 mg/kg of chlortetracycline for 12 days revealed 1 new fraction in the weak basic region. After the use of chlortetracycline for 18 days 2 new fractions in the strong acid region, 1 new fraction at the level of the electrophoretic mobility of asparaginic acid and 2 fractions in the region between neutral and basic amino acids were found. Analysis of the above fractions showed that the blood sera of the control and test rats contained in addition to the free amino acids peptides consisting of 3 to 9 amino acid residues. Some peptides isolated from the sera of the test animals contained amino acids, such as ornithine and citrulline which are not usually contained in proteins.