world of the fungi

It is worthwhile to examine more deeply this strange world, with such peculiar characteristics, and try to highlight those elements that somehow may be pertinent to the problems of oncology.
1) Fungi are heterotrophic organisms and therefore need, as far as nitrogen and carbon are concerned, pre-formed compounds. Of these compounds, simple carbohydrates, for example monosaccarides (glucose, fructose, and mannose) are among the most utilised sugars. This means that fungi, during their life cycle, depend on other living beings, which must be exploited in different degrees for their feeding. This occurs both in a saprophytic way (that is, by feeding on organic waste) and in a parasitic way (that is, by attacking the tissue of the host directly).
2) Fungi show a great variety of reproductive manifestations (sexual, asexual, gemmation; these manifestations can often be observed simultaneously in the same mycete), combined with a great morphostructural variety of organs. All of this is directed toward the end of spore formation, to which the continuity and propagation of the species is entrusted.
3) In mycology, it is often possible to observe a particular phenomenon called heterocarion, characterised by the coexistence of normal and mutant nuclei in cells that have undergone a hyphal fusion.

Nowadays, phitopathologists are quite worried about the creation of individuals that are genetically quite different even from the parents. This difference has taken place by means of those reproductive cycles, which are called parasexual.
The indiscriminate use of phitopharmaceuticals has in fact often determined mutations of the nuclei of many parasite fungi with the consequent creation of heterocarion — and this is sometimes particularly virulent in its pathogenicity (4).
4) In the parasitic dimension, fungi can develop from the hyphas more or less beak-shaped specialised structures that allow the penetration of the host.
5) The production of spores can be so abundant as to always include, at every cycle, tens, hundreds, and even thousands of millions of elements that can be dispersed at a remarkable distance from the point of origin (a small movement is sufficient, for example, to implement immediate diffusion).
6) Spores have an immense resistance to external aggression, for they are capable of staying dormant in adverse conditions for many years, while preserving unaltered their regenerative potentialities.
7) The development coefficient of the hyphal apexes after the germination is extremely fast (100 microns per minute under ideal conditions) with ramification capacity, thus with the appearance of a new apex region that in some cases is in the neighbourhood of 40-60 seconds (6).
8) The shape of the fungus is never defined, for it is imposed by the environment in which the fungus develops.
It is possible to observe, for example, the same mycelium in the simple isolated hyphas status in a liquid environment or in the form of aggregates that are increasingly solid and compact up to the formation of pseudoparenchymas and of filaments and mycelial strings (7).
9) By the same token, it is possible to observe in different fungi the same shape whenever they must adapt to the same environment (this is called dimorphism).
The partial or total substitution of nourishing substances induces frequent mutations in fungi, and this is further proof of their high adaptability to any sub-strata.
10) When the nutritional conditions are precarious, many fungi react with hyphal fusion(among nearby fungi) which allows them to explore the available material more easily, using more complete physiological processes.
This property, which substitutes co-operation for competition, makes them distinct from any other microorganism, and for this reason Buller calls them social organisms.

 

read more PART 6: WORLD OF THE FUNGI CONTINUES

 

Notes
4) Rambelli A., “Fondamenti di micologia”, Bologna 1981, page 35
5) Ibid.
6) Ibid., page 28
7) Verona O., cit. page 5
8) Rambelli A., cit. page 31


Pin It on Pinterest