Ultrastructure of hyphal cells of Trichophyton tonsurans

Document Type : Original Articles

Authors

1 North-Western State Medical University named after I.I. Mechnikov: Kashkin Research Institute of Medical Mycology, Saint Petersburg, Russia

2 Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands

3 Centre of Expertise in Mycology of Radboud University Medical Centre / Canisius Wilhelmina Hospital, Nijmegen, The Netherlands

4 Department of Dermatovenerology, North-Western State Medical University I.I. Mechnikov, St. Petersburg, Russia

Abstract

Background and Purpose: Trichophyton tonsurans is a widely distributed anthropophilic dermatophyte causing different diseases of skin. In the literature limited data are available about the morphogenesis of vegetative mycelium of T. tonsurans and related anthropophilic dermatophytes. The aim of present study was to describe ultrastructural patterns of development, cellular organellography and septal pore apparatus structure of in vitro growing vegetative mycelium of T. tonsurans.
Materials and Methods: Trichophyton tonsurans strain RCPFF 214/898 was grown on solid Czapek’s Agar (CzA) at 28ºС. For investigation of colonies morphology we used methods of light-, scanning and transmission electron microscopy (SEM and TEM).
Results: Differences in morphogenesis of aerial and substrate hyphae were revealed. Mitochondrial reticulum and fibrosinous bodies were shown in T. tonsurans for the first time. The septal pore apparatus in hyphal cells of was comprised Woronin bodies and septal pore plugs. Woronin bodies (0.18 μm), located with 1‒4 near the pore, were spherical, membrane-bound, and had a homogeneous, electron-dense content. The cells of aerial and submerged hyphal cells of T. tonsurans contain two nuclei.
Conclusion: Mature cells of substrate hyphae appeared more active than comparable cells in the aerial mycelium. During the maturation process, the differences in number and morphology of mitochondria, number of vacuoles, and in the synthesis of different types of storage substances were revealed. Presence of “mitochondrial reticulum” and variable types of storage substances in submerged hyphal cells suggested higher levels of metabolic activity compared to aerial mycelium.
 

Keywords


1. De Hoog GS, Guarro J, Gené J, Figueras MJ. Atlas of clinical fungi. 3rd ed. Tarragona, Spain: Rovira i Virgili University; 2013.
2. Gupta AK, Mays RR, Versteeg SG, Piraccini BM, Shear NM, Piguet V, et al. Tinea capitis in children: a systematic review of management. J Eur Acad Dermatol Venereol. 2018; 32(12):2264-74.
3. Gupta AK, Summerbell RC. Increased incidence of Trichophyton tonsurans tinea capitis in Ontario, Canada between 1985 and 1996. Med Mycol. 1998; 36(2):55-60.
4. el Fari M, Gräser Y, Presber W, Tietz HJ. An epidemic of tinea corporis caused by Trichophyton tonsurans among children (wrestlers) in Germany. Mycoses. 2000; 43(5):191-6.
5. Rasnatovskiy KI, Rodionov АN, Kotrechova LP. Dermatomycoses. The guide for doctors. Moscow: Publishing House; 2006. P. 183.
6. Kandemir H, Dukik, K, Hagen F, Ilkit M, Gräser Y, de Hoog GS. Polyphasic discrimination of Trichophyton tonsurans and T. equinum from humans and horses. Mycopathologia. 2019; 19:344-9.
7. Amer AA, Tana M, Diab NA, el Moughith A, el Harras M. Ultrastructure of Trichophyton violaceum. Int J Dermatol. 1993; 32(2):97-9.
8. Naka W, Fukuda T, Ohmi T, Kanai K, Nishikawa T. Ultrastructure of Trichophyton mentagrophytes stained with neutral red. J Med Vet Mycol. 1995; 33(2):141-3.
9. Savitskaya TI, Vasilyeva, NV, Martynov AA, Stepanova AA, Rasnatovskiy KI. Electron-microscopic investigations grooving in vitro cells of Trichophyton rubrum (Castell.) Semon Probl Med Mycol. 2007; 9(2):20-5.
10. Stepanova AA. Ultrastructure of the cells of Trichophyton violaceum Sabour. Probl Med Mycol. 2010; 12(2):36-42.
11. Yue X, Li Q, Wang H, Sun Y, Wang A, Zhang Q, et al. An ultrastructural study of Trichophyton rubrum induced onychomycosis. BMC Infect Dis. 2015; 15:532.
12. Pock-Steen B, Kobayasi T. Ultrastructure of the hyphal wall and septum of Trichophyton mentagrophytes. J Invest Dermatol. 1970; 55(6):404-9.
13. Степанова АА, Синицкая ИА. Ультраструктура Trichophyton mentagrophytes var. interdigitale Blanchard. Probl Med Mycol. 2004; 6(2):119-20.
14. Sagar K. Structural alterations in plant compound treated Trichophyton tonsurans. The Internet J Microbiol. 2008; 7:1-4.
15. Mochizuki T, Anzawa K, Sakata Y, Fujihiro M. Simple identification of Trichophyton tonsurans by chlamydospore-like structures produced in culture media. J Dermatol. 2013; 40(12):1027-32.
16. Васильев АЕ, Камалетдинова ФИ. О фиброзиновых тельцах грибных клеток. Докл АН СССР. 1988; 301(4):982-4.
17. Harder DE. Electron microscopy of urediospore formation in Puccinia coronata avenae and P. graminis avenae. Can J Botany. 1976; 54(9):1010-9.
18. Hassan ZM, Littlefield LJ. Ontogeny of the uredium of Melampsora lini. Can J Botany. 1979; 57(6):639-49.
19. Степанова АА, Синицкая ИА. Цитология клеток выращенного in vitro вегетативного мицелия Aspergillus versicolor (Vuill.) Tiraboshi. Probl Med Mycol. 2006; 8(3):22-8.
20. Stepanova AA, Vasilyeva NV, Zhang F, Tong D. Ultrastructural investigation of growing in vitro cells of vegetative mycelium of Aspergillus candidus Link. Probl Med Mycol. 2016; 18(2):23-7.
21. Vasilyeva NV, Stepanova AA, Sinitskaya IA, Semenov VV. Comparative ultrastructural investigations of Cryptococcusneoformans strains with different virulence. Probl Med Mycol. 2005; 7(2):99.
22. Stepanova AA, Vasilyeva NV, Yamaguchi M. Electron microscopy of autopsy material from the human brain cryptococcosis and aids. Probl Med Mycol. 2015; 17(1):35-40.
23. Stepanova AA, Synitskaiya IA. Ultrastructure of the cells of vegetative mycelium Aspergillus flavus Link, growing in vitro. Probl Med Mycol. 2006; 8(1):40-5.
24. Stepanova AA, de Hoog GS, Vasilyeva NV. Intra- and interspecific diversity of ultrastructural markers in Scedosporium. Fung Biol. 2016; 120(2):147-54.
25. Muller WH, Montijn RC, Humbel BM, van Aelst AC, Boon EJM, van der Krift TP, et al. Structural differences between two types of basidiomycete septal pore caps. Microbiology. 1998; 144(7):1721-30.