After rainy periods in the country as a child I remember seeing the magical sprinkling of white dots barely visible amongst the pastures beside a tranquil river which meandered behind our family home- the arrival of mushrooms! Alone in the company of early morning dews at daybreak I would fill my billycan for a tasty breakfast. There was that special feeling of responsibility in distinguishing between edible and dangerous toxic varieties.
The mushroom has captured our imagination from antiquity when the consumption of ‘magic mushrooms’ containing the chemical hallucinogen (psilocybin) engendered mystical religious type feelings. Some toxic varieties in Australia when consumed can potentially be fatal or cause permanent liver damage. However mushrooms undoubtedly are best known as an attractive nutritional addition to our diet, being high in carbohydrates and providing more protein than green vegetables. Mushrooms belong to the fungi family and although fungi’s cause the majority of plant and crop diseases we can thank the smaller types which are used effectively for the production of bread, beer, wine, cheese, vitamins and penicillin.
The biology of fungi is interesting on a number of counts in terms of composition and evolution. Fungi represent the first life form to colonise the earth, well before the emergence of land based plants. Unlike plants which have leaves representative of a vascular system and which can reproduce via flowers and seeds, fungi reproduce through spores. They vary enormously in size and rely mainly on dead and dying organisms for their food supply. Their DNA is more closely aligned to animals than to plants.
Mushrooms researchers are increasingly becoming excited over the many exciting possibilities in their applications such as treating cancer or in cleaning up toxic wastes.
You can read more about just a brief smattering of some more recent discoveries on Science Daily by clicking here or by simply reading my extracted summaries below.
Dr Cornelia de Moor of The University of Nottingham and her team have investigated a drug called cordycepin, which was originally extracted from a rare kind of wild mushroom called cordyceps and is now prepared from a cultivated form. Dr de Moor said: “Our discovery will open up the possibility of investigating the range of different cancers that could be treated with cordycepin.
More discoveries of Mushrooms that glow in the dark
San Francisco State University Biology Professor Dennis Desjardin and colleagues discovered the fungi in Belize, Brazil, Dominican Republic, Jamaica, Japan, Malaysia and Puerto Rico. The discoveries include four species new to science and three new reports of luminescence in known species. Three quarters of glowing mushrooms, including the species described in the study, belong to the Mycena genus, a group of mushrooms that feed off and decompose organic matter as a source of nutrients to sustain their growth.
"What interests us is that within Mycena, the luminescent species come from 16 different lineages, which suggests that luminescence evolved at a single point and some species later lost the ability to glow," said Desjardin, lead author of the study. He believes that some fungi glow in order to attract nocturnal animals that aid in the dispersal of the mushroom's spores which are similar to seeds and are capable of growing into new organisms.
Mushrooms may also prove effective to cleaning up toxic contaminations in land areas.
This type of mushroom carries out an indiscriminate acid attack on the mineral particles of the soil and absorbs elements in quantities relative to the mineralogical composition of the soil. "In some contaminated soils, or those with particular mineralogical characteristics, the mushrooms collected can reach such high concentrations of toxic elements that their consumption would be unadvisable," reveals the researcher
Chernobyl tragedy teaches us that Fungus Feeds on Radiation
Researchers at the Albert Einstein College of Medicine (AEC) have found evidence that the fungi possess another talent beyond their ability to decompose matter, the capacity to use radioactivity as an energy source for making food and spurring their growth.
Detailing the research in Public Library of Science ONE, AEC's Arturo Casadevall said his interest was piqued five years ago when he read about how a robot sent into the still-highly-radioactive Chernobyl reactor had returned with samples of black, melanin-rich fungi that were growing on the ruined reactor's walls. "I found that very interesting and began discussing with colleagues whether these fungi might be using the radiation emissions as an energy source," explained Casadevall.
Casadevall and his co-researchers then set about performing a variety of tests using several different fungi. Two types - one that was induced to make melanin (Crytococcus neoformans) and another that naturally contains it (Wangiella dermatitidis) - were exposed to levels of ionizing radiation approximately 500 times higher than background levels. Both of these melanin-containing species grew significantly faster than when exposed to standard background radiation.
"Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum - ionizing radiation - to benefit the fungi containing it," said co-researcher Ekaterina Dadachova.
Investigating further, the researchers measured the electron spin resonance signal after melanin was exposed to ionizing radiation and found that radiation interacts with melanin to alter its electron structure. This, they believe, is an essential step for capturing radiation and converting it into a different form of energy to make food. Until now, melanin's biological role in fungi - if any - had been a mystery. Interestingly, the melanin in fungi is no different chemically from the melanin in our skin, leading Casadevall to speculate that melanin could be providing energy to skin cells.
And radiation-munching fungi could be on the menu for future space missions. "Since ionizing radiation is prevalent in outer space, astronauts might be able to rely on fungi as an inexhaustible food source on long missions or for colonizing other planets," noted Dadachova.
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