Морфологічні характеристики фаз росту грибів роду Mucor та Rhizopus

Abstract

Було вивчено морфологічні характеристики грибів роду Mucor і Rhizopus за різних фаз росту. Встановлено, що означені мікроміцети в процесі розвитку проходять п’ять стадій росту, характерних для більшості мікроміцетів. Виявлено, що 4-5 доба культивування є найбільш інформативною з точки зору ідентифікації грибів, що відповідає завершенню фази прискореного нерівномірного росту та фазі експоненціального росту.

Fungi of the family Mucoraceae are contaminated pathogens and saprophytic microorganisms. In the case of penetration into a susceptible organism, they are capable of causing a disease called mucormycosis. More often, the causative agents of mucormycosis in different species of animals and humans is the fungi of the genera Mucor, Rhizopus, Absidia and Mortierella. The reproduction and survival of fungi is ensured by the spores formation process. For pathogenic micromycetes spores have a special meaning. The invasion of a mycosis causative agent is occurs to a receptive organism due to spores. The mold fungi identification in laboratory conditions is based on morphological characteristics of culture in asexual reproduction. The primary aim of this study is to determine the fungal growth phases of morphological characteristics for the genus Mucor and Rhizopus and to establish the optimal term for it identification. The present study is the first on detail description of the fungal growth phases of the genus Mucor and Rhizopus. As a object of study used isolates Mucor ramosissimus Samutsevitsch, Rhizopus spp. from pathological material of died poultry. Cultivation of fungi conducted on sabouraud dextrose agar at 26 °C during 7 days. The concentration of colonied forming units per у 1 sm3 of suspension determinated in cytometric hemocytometer. The morphological characteristics of the fungal growth phases of the genus Mucor and Rhizopus has been studied. It was also established, that fungi of genus Mucoraceae pass through the five phases of growth are common in majority of micromycetes. However, they are accompanied specific and consistent macroscopic and microscopic changes of cultures. The first phase of growth (phase of spore germination) in the genus Mucor and Rhizopus in microscopic level is accompanied by increasing of spore volume. Further the shell of the spore is broken and the primary mycelium develops (first day of cultivation). The second phase of growth (log phase) is characterized by mycelium development and it ramification (second day of cultivation). Herewith mycelium is differentiated on substrate and air. The third phase (phase of accelerated uneven growth) is accompanied by formation of sporangies and pigmentation of colonies (continues from second to the fourth day). The fourth phase (phase of exponential growth) in the genus Mucor and Rhizopus manifests itself by increasing of vegetative mycelium total weight, deceleration of sporangies forming (recorded on the fifth day of cultivation). The fifth phase of growth (aging) is accompanied by destroying of conidial heads and spore releasing with further autolysis of mycelium (from fifth to sixth daу). As it follows from the findings presented in this study that the most informative term of cultivation for identifiation of genus Mucor and Rhizopus is the fourth or fifth day. This term corresponds to corresponds to completion of phase of accelerated uneven growth and phase of exponential growth.