TITLE:
The Ancestors of Cryptococci Appeared on Earth 600 Million Years Ago
AUTHORS:
Petr Nikolayevich Kolosov
KEYWORDS:
Ancestors of Cryptococci, Cryptococcosis, Cells, Yeast Fungi, Algae, Stromatolites, Neoproterozoic, Eastern Siberia
JOURNAL NAME:
Open Access Library Journal,
Vol.9 No.8,
August
22,
2022
ABSTRACT: The purpose of the research is to study the early forms of life in the Neoproterozoic. To achieve this goal, the author has conducted the search for microfossils in stromatolites and has systematically identified the detected forms. In Eastern Siberia, 600-million-year-old Neoproterozoic rocks host columnar stromatolites. They were formed in the sublittoral areas of the warm sea and consisted almost entirely of mineralized (silicified) remains of yeast fungi that, during their life cycle, parasitized the green algae thallus. The combined presence of fungi and algae was established in stromatolite samples using a scanning electron microscope (SEM). In the same stromatolite sample, the world’s first well-preserved mineralized (silicified) early forms of cryptococci were discovered. They are represented primarily by round, individual budding cells that consist of central and peripheral parts. The found microorganisms were identified into a new genus and type species. The latter evolved as yeast fungi and had characteristics similar to the modern Cryptococcus neoformans, from which it differed in a smaller size. It appears that the early ancestors of cryptococci, which invoke Cryptococcosis, occurred on Earth at circa 600 Ma. For such a long period (part of the Neoproterozoic and the entire Phanerozoic) of their presence on Earth, the environment conditions have repeatedly changed from aquatic to terrestrial. This may have led to the fact that cryptococci, unlike the Neoproterozoic ancestors, became more advanced in physiological terms (evolutionarily advanced), and could adapt to various environments and affect human lungs, skin, limbs, etc.