Extensive Molecular Studies on Rock Inhibiting Black Fungi Isolated from Djoser Pyramid

Summary

Stone surface are complex environments with harsh conditions that is inhabited with several microorganisms, some in which use an enzymatic activity to inhibit and decay stones and rocks for nutrients. As well, stone structures and monuments are vulnerable to such organisms causing what is known as bio-deterioration. Rock inhibiting fungi (RIF) are key organisms that play a considerable role for the deterioration of many cultural heritage sites worldwide. In Egypt, archeological sites and prehistoric stone monuments represents an important part of our cultural heritage and national income, especially pyramids. RIF Never been reported in Egypt, however a primary study on oldest stone monument in the world “Djosar pyramid” isolated a RIF meristematic black fungus named Pseudotaeniolina globosa using multi-locus molecular identification. The Egyptian isolate showed a degree of variation differs from what was previously isolated from Italy, Germany, and Netherlands. The current proposal aim to study the isolate extensively on 1) molecular level (using next generation sequencers based methods), 2) Physiological level (experiments on temperature and solar radiation fluctuations) and 3) to search for a biological controller (e.g. Bacteria or other type of fungus). The proposed study will help to characterize the isolated RIF from Egypt and its effect on the Djosar pyramid and similar archeological sites in Egypt. The main outcome of this investigation is the prevention & control strategy that would be designed based on the full awareness of this kind of RIF, its behavior and its role in bio-deterioration, along with the other researches have been reported based on weathering deterioration to preserve the Egyptian cultural heritage.

Achievements

Rock-inhabiting fungi (RIF) are meristematic and melanized microorganisms associated with rock and stone substrates, and their role in monument decay remained underestimated for a long time. The physical, chemical, and biological factors are playing a combined role in the weathering of archeological sites suffering from biodeterioration aspects. The RIF species, mostly from genera e.g., Alternaria, Aspergillus, Cladosporium, Helminthosporium, and Penicillium, were previously reported from Egyptian archaeological remains, antiques, and historical buildings in Egypt. In our report, Pseudotaeniolina globosa DPS10 isolate, was extensively characterized at physiological and molecular levels compared to international strains from Italy, Germany, Austria and Japan. On one hand, the physiological characterization included high levels of stress tolerance, exposure to UV radiation, high temperature, and inhabiting ability on limestones. On the other hand, the molecular characterization was performed using next generation sequencing technique. Even though the DPS10 is P. globosa species confirmed by ITS2 sequences, however, the DPS10 was found much more tolerant than others to extreme salinity levels reaches the maximum known levels in the kingdom fungi (5.2 M = 30% NaCl) and capable of inhabiting rocks with high salinity levels (limestones). The molecular characterization showed high adaptive genetic divergence from the other isolates due to the nature of the variable genes detected by the molecular characterization. The Egyptian isolate is a well-adapted ecotype to harsh and extreme environments. Its potential biodeteriorating effect on our cultural heritage requires special attention to design conservation plans and solutions includes Imidazole as antifungal agent to limit its presence and distribution.

List of Publications from the Project

Partners

Project Members

• Samah Mohamed Rizk Soliman
• Mahmoud Magdy Abdallah Awad

Project Leaders

• Mohamed Abdelsalam Rashed