The inhibition of mouse bone collagenase by lysozyme

New insights into the relationships between egg maternal components: the interplays between albumen steroid hormones, proteins and eggshell protoporphyrin

Recent studies have shown that the egg yolk maternal components, which are a mixture of substances that can affect the developing embryo, do not act separately but are interconnected and co-adapted. Surprisingly, no study to date has focused on the associations between maternally derived albumen steroids and albumen and eggshell compounds with pleiotropic effects. Eggshell pigment protoporphyrin (PROTO IX) should provide primary antimicrobial protection for eggs, but as a proven pro-oxidant, it may compromise female fitness. Abundant albumen proteins ovotransferrin (OVOTR) and lysozyme (LSM) have been shown to have antimicrobial, antioxidant, immunoregulatory and growth-regulatory roles. To investigate associations between albumen steroids and OVOTR, LSM and eggshell cuticle PROTO IX, we used chicken eggs with differently pigmented eggshells. We found that albumen steroid hormones were strongly intercorrelated. In addition, we revealed that albumen LSM and testosterone (T) were positively associated, while a negative association was found between albumen LSM and pregnenolone (P5). Eggshell cuticle PROTO IX was negatively associated with the concentration of albumen 17α-hydroxypregnenolone (17-OHP5). Finally, of all the hormones tested, only the concentration of albumen 17-OHP5 correlated negatively with egg volume and varied with eggshell colour and chicken breed. Although experimental evidence for the effect of maternal albumen steroids on avian developing embryo is still scarce, our study is the first to highlight co-variation and potential co-adjustment of maternally derived albumen steroids, proteins and eggshell cuticle pigment suggesting similar allocation mechanisms known for yolk maternal compounds with the potential to influence the avian embryo and offspring phenotype.

Temperature-induced changes in egg white antimicrobial concentrations during pre-incubation do not influence bacterial trans-shell penetration but do affect hatchling phenotype in Mallards

Microbiome formation and assemblage are essential processes influencing proper embryonal and early-life development in neonates. In birds, transmission of microbes from the outer environment into the egg’s interior has been found to shape embryo viability and hatchling phenotype. However, microbial transmission may be affected by egg-white antimicrobial proteins (AMPs), whose concentration and antimicrobial action are temperature-modulated. As both partial incubation and clutch covering with nest-lining feathers during the pre-incubation period can significantly alter temperature conditions acting on eggs, we experimentally investigated the effects of these behavioural mechanisms on concentrations of both the primary and most abundant egg-white AMPs (lysozyme and avidin) using mallard (Anas platyrhychos) eggs. In addition, we assessed whether concentrations of egg-white AMPs altered the probability and intensity of bacterial trans-shell penetration, thereby affecting hatchling morphological traits in vivo. We observed higher concentrations of lysozyme in partially incubated eggs. Clutch covering with nest-lining feathers had no effect on egg-white AMP concentration and we observed no association between concentration of egg-white lysozyme and avidin with either the probability or intensity of bacterial trans-shell penetration. The higher egg-white lysozyme concentration was associated with decreased scaled body mass index of hatchlings. These outcomes demonstrate that incubation prior to clutch completion in precocial birds can alter concentrations of particular egg-white AMPs, though with no effect on bacterial transmission into the egg in vivo. Furthermore, a higher egg white lysozyme concentration compromised hatchling body condition, suggesting a potential growth-regulating role of lysozyme during embryogenesis in precocial birds.

Effects of experimentally increased in ovo lysozyme on egg hatchability, chicks complement activity, and phenotype in a precocial bird

In birds, spectrum of egg white proteins deposited into the egg during its formation are thought to be essential maternal effects. Particularly, egg white lysozyme (LSM), exhibiting great between and within species variability, is considered to be essential for developing avian embryos due to its physiological, antimicrobial, and innate immune defense functions. However, there have been few studies investigating effects of LSM on early post-hatching phenotype, despite its broad physiological and protective role during embryogenesis. Here, we test how experimentally increased concentrations of egg white LSM affect hatchability in Japanese quail (Coturnix japonica) and chick phenotype immediately after hatching (particularly body weight, tarsus length, plasma LSM concentration, and plasma complement activity). Chicks from eggs with increased LSM concentration displayed reduced tarsus length compared to chicks from control eggs while hatchability, body weight and plasma LSM concentration were unaffected. It is worth noting that no effect of increased in ovo lysozyme on eggs hatchability could be related to pathogen-free environment during artificial incubation of experimental eggs causing minimal pressure on embryo viability. While tangible in vivo mechanisms during avian embryogenesis remain to be tested, our study is the first to document experimentally that egg white LSM appears to have growth-regulation role during embryo development, with possible underlying phenotypic consequences in the early post-hatching period in precocial birds.

Clinical biochemistry of tears

The composition of tear fluid as it exists in the conjunctival fornix and in the precorneal tear film is of a complicated nature. The precorneal tear film is a physically inhomogenous system, produced by the lacrimal glands, the accessory lacrimal glands and the goblet cells of the conjunctiva and the Meibomian glands of the lid margin. The method of collection is crucial for the quantity and concentration of a great number of different compounds that have been demonstrated in tears. A survey is given of the literature concerning tears as they are composed of proteins, enzymes, lipids, metabolites, electrolytes and drugs, the latter secreted during therapy. Clinical applications of the determination of several compounds for diagnosis or for monitoring drug therapy are summarized.

Production of collagenase inhibitor by the growth cartilage of embryonic chick bone: isolation and partial characterization

Production of collagenase and collagenase inhibitors by the explants of epiphyseal, metaphyseal and diaphyseal regions of embryonic chick limbs during development has been investigated. Collagenase-inhibitory activity was first detected in the culture medium of the diaphyseal region of limbs at stage 36 where cartilage matrix erosion began to occur. However, neither active nor latent collagenase was detected in the media of any regions examined. At stage 38 and later, the maximum production of the inhibitory activity was observed in the explants of metaphyseal region (growth cartilage), while collagenase production was only in the diaphyseal region. Two collagenase inhibitors were isolated and purified approximately 150 fold from the culture medium of stage 38 and 43 metaphyseal regions of limbs by anion- and cation-exchange chromatography followed by gel filtration. The inhibitors are cationic proteins with the same molecular weight of approximately 25,000, but slight difference in molecular charge. They are heat-stable and inhibit collagenases from tadpole skin, chick bone and skin and human granulocytes and gelatinases from human granulocytes and chick skin as well as trypsin, but not Clostridium histolyticum collagenase. A possible function of the inhibitors in multistep regulations of the collagen-degrading enzyme system at the region of osteo-chondral transition is discussed.

Purification of tadpole collagenase and characterization using collagen and synthetic substrates

Tadpole collagenase hydrolyzed native and denatured collagen and synthetic peptides with sequences of 2,4-dinitrophenyl-L-prolyl-L-leucylglycyl-L-isoleucyl-L-alanylglycyl-L-arginie amide and 2,4-dinitrophenyl-L-prolyl-L-glutaminyl-glycyl-L-isoleucyl-L-alanylglycyl-L-glutaminyl-D-arginine. The specific enzyme activity against the latter substrate and collagen fibrils is found to be 933 nmol/min per mg protein and 8440 units (microgram collagen degraded/min), respectively. Optimum pH for the enzyme is 7.5-8.5. A collagenase complex with alpha2-macroglobulin did not hydrolyze collagen fibrils, but digested the synthetic substrates at the Gly-Ile bond. The amino acid composition of the enzyme was determined. Immunoelectrophoresis of the enzyme at pH 8.6 against anti-tadpole collagenase rabbit immunoglobulin G shows a single precipitin line at a position migrating faster than human serum albumin and corresponding to enzyme activity against collagen fibril and synthetic substrates.

Inhibition of new blood vessel formation in mice by systemic administration of human rib cartilage extract

1 M HCl-guanidine extract of human funnel chest rib cartilage administered i.v. to mice decreased specifically vasoproliferation induced by intradermal injection of allogeneic murine lymphocytes.

Connective tissue lysozyme in health and disease

As the lysozyme story continues to unfold, rheumatic disease is one area where the study of this fascinating protein will be most important. The special biochemical features of lysozyme--its hexosaminidase function, its ability to bring about transglycosylation, its homology to alpha-lactalbumin, and its cationic nature--suggest that the connective tissues may prove to be the key to the understanding of the function of lysozyme. As methods for its accurate measurement become standardized, better data on the activity of the enzyme in various tissues and body fluids, in both health and disease, will be forthcoming. As additional studies are done to ascertain which of the hypothetical functions attributed to lysozyme are of significance in vivo, it will be the student of the connective tissues and the diseases thereof who can be expected to profit most from an udnerstanding of the role of lysozyme in mammalian biology.