Purification and partial characterization of lysozyme from mouse small intestine

Summary Lysozyme was isolated from the small intestine of mice by combined ion-exchange and molecular sieve chromatography. This lysozyme differs from that isolated from the urine of mice with monocytoma in amino acid composition, and migration rate in cellulose acetate electrophoresis. As intestinal lysozyme originates at least in part from the Paneth cell, our results point towards the existence of isozymes of lysozymes in mice.Acknowledgments. Supported by grant No. 20159 from the Fonds voor Wetenschappelijk Geneeskundig Onderzoek, Brussel, Belgium. We should like to thank Mrs.Parein for skillful technical assistance.     

A method for automatic recording of serum lysozyme activity with the fragiligraph

Summary A quick and simple method for the estimation of lysozyme activity using the Fragiligraph, was described. Diminution of turbidity in a suspension ofMicrococcus lysodeikticus produced by the addition of standard lysozyme (hen egg white) or serum sample, was continuously recorded for 5 min by the Fragiligraph. The normal mean serum lysozyme activity value obtained by this method is 6,80 g/ml±1.85.We gratefully acknowledge the excellent technical assistence of MissM. Touma.     

Antioxidant activity of mouse liver and kidney extracts

Zusammenfassung Die hemmende Wirkung wässeriger Leber- und Nierenextrakte von Mäusen auf die DOPA-Auto-Oxydation wurde geprüft. Leber- und Nierenwerte waren von gleicher Grössenordnung und etwa dreimal grösser als die früher für Mäuse- und Menschenhaut bestimmten Werte. Der Hemmfaktor besteht zum grossen Teil aus Eiweiss und konnte in einen -SH-Gruppen enthaltenden, hitzeempfindlichen Teil und einen -SH-Gruppen-freien, hitzestabilen Teil getrennt werden. Die mögliche Bedeutung solcher Hemmstoffe für die Zelle wird erörtert.     

A method for automatic recording of serum lysozyme activity with the fragiligraph.

A quick and simple method for the estimation of lysozyme activity using the Fragiligraph, was described. Diminution of turbidity in a suspension of Micrococcus lysodeikticus produced by the addition of standard lysozyme (hen egg white) or serum sample, was continuously recorded for 5 min by the Fragiligraph. The normal mean serum lysozyme activity value obtained by this method is 6,80 mug/ml +/- 1.85.     

Evidence for a novel racemization process of an asparaginyl residue in mouse lysozyme under physiological conditions

We examined chemical reactions in mouse lysozyme after incubation under physiological conditions (pH 7 and 37°C). After incubation for 8 weeks, racemization was observed specifically at Asn127 among the 19 Asp/Asn residues in mouse lysozyme. Furthermore, analysis of the primary structure showed that the racemized residue was not Asp, but Asn, which demonstrates that deamidation and isomerization did not occur. These results mean that this racemization occurs without forming a succinimide intermediate. This is the first example of D-asparaginyl formation in a protein occurring during the racemization process under physiological conditions.Received 16 September 2004; received after revision 26 October 2004; accepted 12 November 2004     

Elucidation of the relationship between enzyme activity and internal motion using a lysozyme stabilized by cavity-filling mutations

We investigated the activity and the internal motions of a stabilized mutant hen lysozyme (HEL) in which the residues M12 and L56 were mutated to L and F, respectively (LF mutant HEL). The result of the activity measurements against glycol chitin at various temperatures suggested that the temperature dependence of the activity of LF mutant HEL shifted to the high-temperature side compared with that of wild-type HEL. The detailed internal motions of LF mutant HEL in the absence and presence of a substrate analogue, (NAG)₃, were examined by model-free analysis at 35°C. The results showed that the internal motions of LF mutant HEL in the presence of (NAG)₃ were drastically restricted compared with those in wild-type HEL. Our findings thus suggested that the mutation to the stabilized lysozyme restricted internal motions required for the enzymatic reaction.Received 8 February 2005; accepted 10 March 2005Y. Yoshida and T. Ohkuri contributed equally to this work.     

Glutamine synthetase activity during mouse brain development

The specific activity of glutamine synthetase (GS) in mouse brain was 2-fold higher in the olfactory bulbs than in other regions. After birth, the specific activity of GS increased more rapidly in medulla oblongata and in olfactory bulbs, than in cerebral and cerebellar cortex. The activity of GS in primary cultures of brain hemispheres increased more slowly than in homogenates of whole brains. However, when astroblasts were treated in vitro with glucocorticoids or mouse brain extracts, GS activity reached 4 times the level measured in the homogenate of an adult mouse brain. We conclude that levels of GS activity may relate to the maturation of astrocytes, and propose that GS may be used as a marker of astrocytic maturation.     

Glutamine synthetase activity during mouse brain development

Summary The specific activity of glutamine synthetase (GS) in mouse brain was 2-fold higher in the olfactory bulbs than in other regions. After birth, the specific activity of GS increased more rapidly in medulla oblongata and in olfactory bulbs, than in cerebral and cerebellar cortex. The activity of GS in primary cultures of brain hemispheres increased more slowly than in homogenates of whole brains. However, when astroblasts were treated in vitro with glucocorticoids or mouse brain extracts, GS activity reached 4 times the level measured in the homogenate of an adult mouse brain. We conclude that levels of GS activity may relate to the maturation of astrocytes, and propose that GS may be used as a marker of astrocytic maturation.     

Effect of cadmium on polyribosome structure and function in mouse liver

Summary Cadmium chloride injected to mice (20 moles/kg) provokes in the livers a degradation of polyribosomes and diminishes their protein synthetic ability measured in vitro. CdCl₂ added in a final concentrations between 30 and 100 M to the protein synthetic cell-free system derived from livers of control mice inhibits its activity.Acknowledgments. We are grateful to Prof. P. Sokoli for helpful discussion. The work was supported by Wellcome Trust grant and by a gift of chemicals from Kemika, Zagreb. We are grateful to both these organizations.     

Lack of distant relationships between lysozyme Ch and hen egg white lysozyme: computer comparison studies

Summary A computer search, made for distant relationships between lysozyme Ch, hen egg white lysozyme, and bacteriophage T4 lysozyme, revealed no unusual similarities in their amino acid sequences. Also, antibodies generated against lysozyme Ch failed to cross react with hen egg white lysozyme and vice versa. These lysozymes most likely represent examples of convergent evolution.Acknowledgments. This research was supported by Public Health Service Grant AI-15531 and the Biomedical Research Support Grant RR-05424.To whom all communication should be addressed.     

Chemical structure and biological activity ofo-disubstituted derivatives of benzene

Zusammenfassung Es wurden die i.v. LD₅₀ einer Gruppeo-disubstituierter Benzolderivate, welche alle Kombinationen der erwähnten Substituenten enthielt, bestimmt. Die quantitative Korrelation zwischen chemischer Struktur und biologischer Aktivität wird in einer Gleichung gefasst.     

Joseph H. M. Wedderburn and the structure theory of algebras

Archive for History of Exact Sciences -     

Chemical structure and biological activity ofp-disubstituted derivatives of benzene

Zusammenfassung Es wurden die i.v. LD₅₀ einer Gruppep-disubstituierter Benzolderivate, welche alle Kombinationen der erwähnten Substituenten enthielten, in Polyvinylpyrrolidonlösungen bestimmt. Der Zusammenhang zwischen der chemischen Struktur dieser Verbindungsklasse und ihrer biologischen Aktivität konnte mit einer vorgeschlagenen Gleichung beschrieben werden.     

Studies onHolothuria polii (Echinodermata) antibacterial proteins. I. Evidence for and activity of a coelomocyte lysozyme

Summary Lysozyme activity has been detected in coelomocyte lysate of the echinodermHolothuria polii. The bacteriolytic reaction was stable when the lysate was heated in acidic buffer but heat-labile in alkaline medium. An incubation temperature of 35°C, acidic pH values (5.2 and 6.2) and an ionic strength of 0.175 were found to be the best conditions for the coelomocyte enzymatic activity. A low level of lysozyme was also evidenced in cell-free coelomic fluid where it could represent a basal defense level of bacteriolytic molecules released by the coelomocytes.Acknowledgments. This work was supported in part by a grant from MRES (C. C.). The authors thank M. Lasségues and F. Lassalles for their help and criticism.     

Interaction of pepsin with lysozyme

Riassunto L'autore ha studiato il complesso che si forma dall'interazione della pepsina con il lisozima.Vengono riferiti i risultati ottenuti studiando le caratteristiche torbidimetriche, elettroforetiche e di sedimentazione all'ultracentrifuga del complesso pepsinalisozima.Il complesso ha il punto isoelettrico a pH 7.3, ed ha una costante di sedimentazioneS ₂₀=4.9×10^–13.