Frog lysozyme. I. Its identification, occurrence as isozymes, and quantitative distribution in tissues of the leopard frog, Rana pipiens,

Abstract

In the course of examining the etiology of the Lucké renal adenocarcinoma of the frog, Rana pipiens, it was found that organs of the normal adult contain bacteriolytic enzymes. These enzymes all satisfied the six criteria for the identification of lysozymes and at least eight forms were separable by polyacrylamide gel electrophoresis. Their qualitative and quantitative distribution was organ-specific. All eight isozymes were found in normal kidney, while liver and spleen contained seven forms; skin, six; ovarian egg, five; and serum, two. In quantitative assays using a radial diffusion test, spleen had the greatest lysozyme concentration, followed in descending order by kidney, liver, skin, and ovary. Serum contained very low amounts. In terms of enzyme activity per animal, ovary was the highest ranking organ. As such a large number of lysozyme isozymes has not been reported in any other organism, their origins and functions are considered in the context of their presence in an ectotherm.

Innate immunity in vertebrates: an overview

“…1,3,21,30 This protein has been found in fish, 30 generally associated with the mucous cuticle, 8,15,31 whereas in amphibians like Rana pipiens eight lysozyme isoforms were identified by chromatographic and electrophoretic methods in the skin, serum, liver, kidney, ovary and spleen, demonstrating lytic capacity on a Micrococcus lysodeikticus-agar suspension. 32 This enzyme has also been identified in anurans like Xenopus laevis 33 and Xenopus tropicalis. 31 In addition, different lysozyme homologues have been isolated from reptiles such as the Chinese soft-shelled turtle (Pelodiscus sinensis), Asian soft-shelled turtle (Amyda cartilagenea) and green sea turtle (Cheloni amydas), demonstrating lytic ability against several strains of Gram-positive and Gramnegative bacteria.…”

“…One of the most active is the lysozyme (muramidase or N‐acetyl muramide glycanohydrolase), an enzyme that lyses bacteria . This protein has been found in fish, generally associated with the mucous cuticle, whereas in amphibians like Rana pipiens eight lysozyme isoforms were identified by chromatographic and electrophoretic methods in the skin, serum, liver, kidney, ovary and spleen, demonstrating lytic capacity on a Micrococcus lysodeikticus ‐agar suspension . This enzyme has also been identified in anurans like Xenopus laevis and Xenopus tropicalis .…”

Review of the Amphibian Immune Response to Chytridiomycosis, and Future Directions

“…Lysozyme is a constitutively expressed antimicrobial enzyme found in body fluids and mucosal linings. Lysozyme from amphibian skin secretions has potent bactericidal activity ( 93 , 94 ). Although typically considered an antibacterial enzyme, lysozyme has also been reported to possess antifungal properties ( 95 , 96 ).…”

Immune defenses of Xenopus laevis against Batrachochytrium dendrobatidis

“…Whether or not B. boreas may secrete lysozyme in the skin is not yet known. An extract of skin from Rana pipiens was previously shown to have an acid-stable protein with lysozyme-like characteristics (67). Thus, lysozyme may be an important bacterial defense mechanism in the mucus of many amphibians.…”