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Ecological contributions of fungi (biochemistry).

Amanita muscaria, a psychoactive basidiomycete fungus

Fungus is a group of unicellular, multicellular, or syncytial spore-producing organisms feeding on organic matter, including moulds, yeast, mushrooms, and toadstools.^[1] Fungi are widely known for their culinary uses, however fungi have a significant ecological impact; fungi impact ecology in both beneficial and harmful ways. Ecological studies have found that in healthy forest soils, 90% of the total living organisms consist of fungi. The remaining 10% are made up of organisms such as nematodes, algae, rotifiers, protozoa, springtails, mites and worms ^[2]. In addition, fungi are used in the agriculture, medicine, research, and biotechnology sectors.^[3]

Fungi may contribute substantially to soil microbial biomass as well as to the genetic diversity among soil microorganisms. ^[4] Fungi can utilize carbohydrates like L-arabinose, D-xylose and cellobiose aerobically and some soil yeasts are also found to assimilate intermediates of lignin degradation as well. ^[4] It has also been shown that fungi can enhance plant growth as well. They do this by expanding the plant's roots and thus making it easier for both the plant and fungi to get nutrients.

new page

1 History
2 Species Types
3 Processes
4 Group Discussion
- 4.1 References Used (indicate name)

History

Fungi are found everywhere in the natural environment and they play fundamental roles in the biosphere. Several biochemical processes controlled by fungi are thus; the recycling of nutrient, plant nutrient acquisition, decomposition of dead biomass, release of gases to the environment. Fungi can respond to processes altered by global change such as soil temperature and moisture, availability of nutrient and atmospheric chemistry.

Decomposition is a vital ecological process driven by fungi. Without decomposition, the world would be filled with piles of dead biomass or dead organic matter. For decomposition to fully take effect, fungi secretes chemical that digests dead organic matter, following the initial decomposition process by detritus. Fungi are saprophytes. Saprophytes together with detritus are essential in the recycling and fragmentation processes of decomposition.(http://science.jrank.org/pages/1967/Decomposition.html)

Contribution of fungi to leaf litter decomposition

contribution of fungi in the decomposition of leaf litter results in the generation of inorganic compounds, fine-particulate organic matter and decomposer biomass.(REFERENCE: Hieber, M., & Gessner, M. O. (2002). Contribution of stream detrivores, fungi, and bacteria to leaf breakdown based on biomass estimates. Ecology, 83(4), 1026-1038.). In ecosystem, decomposition of leaf litters in stream or rivers depends on the activity of invertebrates and microorganism. Fungi and some bacterial mediates the conversion of leaf litters to microbial biomass, the prevalence of fungi in microbial decomposer assemblages has been found in aquatic environment. (REFERENCE:Pascoal, C., & Cássio, F. (2004). Contribution of fungi and bacteria to leaf litter decomposition in a polluted river. Applied and Environmental Microbiology, 70(9), 5266-5273). Not only do fungi contribute to decomposition of leaf litter, they increase the food value of leaves in the aquatic environment. Hyphomycetes fungi which are mostly aquatic have been recognized as playing a major task in microbial decomposition of leaf litter in stream or rivers.(REFERENCE:Pascoal, C., & Cássio, F. (2004). Contribution of fungi and bacteria to leaf litter decomposition in a polluted river. Applied and Environmental Microbiology, 70(9), 5266-5273). When leaf litters fall in aquatic environment, they are colonized and conditioned by fungi by spreading mycelium over the leaf surface and thereby penetrating the leaf. Extracellular enzymes are released to degrade the leaf constituent such as cellulose, hemicelluloses and pectin, thereby making the leaf material more suitable food source for invertebrates in aquatic environment. (REFERENCE:Pascoal, C., & Cássio, F. (2004). Contribution of fungi and bacteria to leaf litter decomposition in a polluted river. Applied and Environmental Microbiology, 70(9), 5266-5273).

Contribution of fungi to the decomposition of soil organic matter/plant residue

Species Types

Many fungal species contribute ecologically, although the most common relationship between a fungi and plants can be seen as Mycorrhiza. A mycorrhiza is a symbiotic relationship in which a fungus can associate with the roots of a vascular plant. In a mycorrhizal association, the fungus has the ability to colonize the host plant's roots. This process generally occurs intracellularly as in arbuscular mycorrhizal fungi (AMF or AM), but may also occur extracellularly as in ectomycorrhizal fungi. The relationship between these fungi and their plant host's is extremely important in maintaining soil growth and soil chemistry. ( REFERENCE: Habte, M. "Mycorrhizal Fungi and Plant Nutrition." Journal of Plant Nutrition 18.10 (1995): 2191-198.) The two morphological types of Arbuscular mycorrhiza, the Arum and Paris, have been found in ~80% of all major plant lineages (Ref (Vladimir, K., & Marcel, B. 2005))

Many Fungi Decomposers use their physical form and enzyme capabilities and metabolism to help decay dead animals and plant remains in the soil. some famous fungi decomposers are :

Zygomycetes: The only saprotrophic zygomyces are found in the mucorales. most of these mucorals re specialized in breaking down starh, fats and proteins, extracellular enzymes such as lipases and proteases are produced during decomposition. the mucolars ability to decompose depends on the proper substrate that can be used bu them and soon to exhausted(REFRENCE :BEEVER ROSS,E 2006)
Basidiomycetes: The saprotophic species of basidiomycetes are the parts adapted morphologically and biochemically to live on cellulose and lignocellulose. basidiomycetes are types of fungi that are able to degrade lignin, and with the help of ants and beetles thses fungi are able to remove woody remains from the ecosystem (REFRENCE :BEEVER ROSS,E 2006)

Processes

Lichens & Pedogenesis

Lichens are organisms made up of both fungi and a photosynthetic partner in which they form a symbiotic relationship. This has actually become one of the most successful ways of nutrient uptake for a fungi. It is because of lichens you have healthy forests and plants all over the planet and importantly creates a habitable soil for photosynthetic organisms to thrive in ^[5] .Soil formation or Pedogenesis is one of the most important impacts that fungi have contributed for organisms in many environments ^[6] . Most lichens are usually grown under rocks and slabs where they act as grazers and degrade the rock into soil. Vasily Dokuchaev has created this equation that involved consequences of climate and biological process involving organisms and minerals ^[7] .

Soil = f(C, PM, O) x time

where C = climate

PM = parent material

O = biological processes

Signal Transduction Pathways

Fungal Decomposition/ Recycling

Decomposition is a general term used to describe the interrelated processes by which organic matter is broken down to CO2 and humus with a simultaneous release of nutrients. (http://lawr.ucdavis.edu/classes/ssc219/biogeo/decomp.htm)

special type of fungi in the soil act as decomposes, plants use nitrogen as a bulding block of tissues of its leaves, woods and even fruits. If no decomposition occurs than all this nitrogen will be stuck inside those dead leafs and stems; making the nitrogen amount available to make new tissues very lttle therefore the growth of plant will start decreasing causing ecological catastrophy since plants are the basic supplies for all human needs. also all these un decomposed leafes and woods will cover the surface of the ground.(REFRENCE IS :Dickinson, C. H. and G. J. F. Pugh. 1974. Biology of plant litter decomposition. 2 volumes. Academical Press, New York. ISBN 0-1221-5001-5.). rate of decomposition is the main factor that effects the speed at which fungi break down the dead matters which can be measured as (Mt) = M0 e-kt (http://nre509.wikidot.com/lecture-5:decomposition-constant-k)

M is the mass of litter at a certain time;
M0 is the initial mass of litter;
e is the base of the natural logarithm;
k is the decomposition constant; and
t is the amount of time passed since the initial measurement

Leaf decomposition is commonly observed throughout many ecosystems, of which fungi can be classified the secondary contributor next to detritivorous invertebrates (shredders). Experimental results show that samples of alder (Alnus glutinosa) and willow (Salix fragilis) leaves placed in a stream during peak leaf fall, and retrieved periodically to determine leaf mass remaining and the biomass of leaf-associated organisms indicated that shredders accounted for approximately 51% of leaf mass loss, while fungi contributed approximately 18%, and bacteria approximately 7%. (REFERENCE IS: Hieber, Mäggi, and Mark O. Gessner)

The decomposition by fungi and baceria is also dependent on:
- tempreture
- moisture
- chemcial composition of organic matter

when the temperature is to high or too low for fungal and bacterial growth the rate of decomposition stars decreasing, also if the leafes carry small amount of nitrogen the rate of decomposition starts becoming low as well since the fungi doesn't have enough nitrogen to use it to build proteins that help in its growth . Another very imoportant factor that will slow down the decomposition rate is low level of oxygen, since fungal growth requires oxygen (REFRENCE IS Mason, C. F. 1976).

Nutrient Uptake

One ecologically important task arbuscular mycorrhizal fungi do is increase the uptake of phosphorus. Phosphorus is a important macronutrient used in all organisms in structures such as nucleic acids, enzymes, coenzymes and phospholipids, as well as being used in cell functions such as the regulation of enzymes, metabolic intermediate activation, the metabolism of energy, and signal transduction cascades. The fungi have access to different sources of soluble phosphate than the plant roots which allows the plant to get phosphate after it has taken up all the phosphate it can after the root level phosphate has been exhausted (REFERENCE: Vladimir, K., & Marcel, B. 2005). In grain, this is most effective when the plant is at maturity. The increased phosphate uptake has been shown to increase crop yield (REFERENCE: Arbuscular Mycorrhizal Fungi Contribute to Phosphorus Uptake by Wheat Grown in a Phosphorus-Fixing Soil Even in the Absence of Positive Growth Responses).

Phosphate is selectively taken up by the fungi cells using specialized membrane proteins called phosphate transporters and proton-ATPases. This process requires energy as it is working against a large concentration and electrochemical gradient. The phosphate taken up can then be bartered with the plant in exchange for photosynthetic sugars (REFERENCE: Vladimir, K., & Marcel, B. 2005). Arbuscules, a type of differentiated hyphae, develop within the cortical cells of the plant root. The plant is able to transport the phosphate across a symbiotic membrane between the arbuscules and the cortical cells. This membrane is also known as the periarbuscular membrane (REFERENCE: Harrison, M. J., Dewbre, G. R., & Liu, J. (2002). A Phosphate Transporter from Medicago truncatula Involved in the Acquisition of Phosphate Released by Arbuscular Mycorrhizal Fungi).

Biochemical By-Products

The arbuscular mycorrhizal fungi(AM) discussed above have many biochemical by-products observed through soil and root analysis of host plants/organisms. Glomalin is a common glycoprotein produced on the hyphae and spores of AM fungi, which has been shown to carry specific Glomalin-related soil proteins or GRSPs. These GRSPs are very common to organic soil matter and have been proven to aid in carbon sequestration, which is the process where carbon dioxide (CO₂) or other forms of carbon are stored for long-term periods. This process of storing carbon species for long periods of time has been shown to slow the release of atmospheric and marine greenhouse gases produced naturally. (REFERENCE: Purin, Sonia; Rillig, Matthias C. (20 June 2007). "The arbuscular mycorrhizal fungal protein glomalin: Limitations, progress, and a new hypothesis for its function". Pedobiologia 51 (2): 123–130.) This process of carbon sequestration carried out by the AM fungi, more specifically the GRSPs have been theorized to have a primary productivity relationship with its ecosystem and has also been shown to aid directly in the ecosystems ability to remain healthy and produce viable soil.

Reference

↑ http://oxforddictionaries.com/definition/english/fungus
↑ http://home.vicnet.net.au/~warringa/meetings_maj04.htm
↑ May, G. S., & Adams, T. H. (1997). The importance of fungi to man. Genome research, 7(11), 1041-1044.
↑ ^4.0 ^4.1 Botha, A. (2011). The importance and ecology of yeasts in soil. Soil Biology and Biochemistry, 43(1), 1-8.
↑ Applied Microbiology and Biotechnology
↑ Applied Microbiology and Biotechnology
↑ Niche Construction: The Neglected Process in Evolution

Group Discussion

chat here

so when is everyone starting this ?

Jordan and I are starting our part today (March 18th). If everyone submits their parts I will look it over the night before and correct the formatting so it all looks the same.

ALSO, just put the reference in brackets like "Blah blah blah - (ah CLASSY writing sean) (Hieber, Mäggi, and Mark O. Gessner. 2002. CONTRIBUTION OF STREAM DETRIVORES, FUNGI, AND BACTERIA TO LEAF BREAKDOWN BASED ON BIOMASS ESTIMATES. Ecology 83:1026–1038.)" and i will add them to the reference page at the end so it has the correct reference format and anchor links

its due march 22, so friday

so i just re-read the outline and it actually has a few headings we "should" be using, you guys think what we have is good or should we add the ones we are missing/ change the titles to these ones? anyways maybe someone could get started on some of the ones not added yet or even just adding to ones to perfect them

"You must include the follow sections on your Wiki (some may be combined if needed):

Definitions Introduction Describe species types involved Describe processes involved Describe history References"

Hey guys sorry for the lack of input had a million things going on. I see there is one heading that hasn't been started yet I have no problem working on that one. If anything else needs to be completed maybe we could post a list and everyone can figure out what they can help with? Looking really good so far! -Amanda

Yeah i think if there were some heading and then everyone takes one and talk fully about it that will be perfect

unless you guys just want to talk about whatever and then we can put them all in order and make it look better? what does everyone think ?

I've got some stuff sort of put together on phosphorus/other nutrient uptake by AM fungi although I'm not exactly sure which heading that goes under, just the processes one? Also was anyone else going to do that? Just not too sure on who is doing what here. - Mark

Christine just posted a message saying to have it done by 4pm friday. I'm pretty sure they can see the time we edit it so please refrain from editing it after 4 or else we might lose marks. Who knows they might even lock us out from editing right at 4 anyways. If everyone can have their part entered by 2 on Friday I can go through it and adjust the formatting and make sure the reference links work, tags are correct, etc. Thanks - Sean

Sounds good @Sean

Thanks Sean that would be great an as a heads up so there isn't any overlap I can do the signal transduction pathways portion and maybe look over everything and se eif any more definitions need to be entered. - Amanda

OKAY since everyone is working on something and its all divided, im going to add to "Fungal Decomposition/ Recycling" and "species type" since those two section dont have enough writings .-ranad

So i finished the "Fungal Decomposition/ Recycling" Part, and i mixed what we had before and my part so now it all make sense, also i added a picture. for the refrence part i did what sean said . - RANDA

Having trouble getting my image (the Phosphate transport) to have the captioning under it. If you click on it it brings you to a the caption but you leave the page. Anyone know how to change that? -Mark

References Used (indicate name)

Sean/Jordan 1) May, G. S., & Adams, T. H. (1997). The importance of fungi to man. Genome research, 7(11), 1041-1044.

Sean/Jordan 2) The importance and ecology of yeasts in soil Soil Biology and Biochemistry (January 2011), 43 (1), pg. 1-8 Alfred Botha

Norbert 3) Hieber, Mäggi, and Mark O. Gessner. 2002. CONTRIBUTION OF STREAM DETRIVORES, FUNGI, AND BACTERIA TO LEAF BREAKDOWN BASED ON BIOMASS ESTIMATES. Ecology 83:1026–1038.

Norbert 4) Habte, M. "Mycorrhizal Fungi and Plant Nutrition." Journal of Plant Nutrition 18.10 (1995): 2191-198.

Norbert 5) Purin, Sonia; Rillig, Matthias C. (20 June 2007). "The arbuscular mycorrhizal fungal protein glomalin: Limitations, progress, and a new hypothesis for its function". Pedobiologia 51 (2): 123–130.

Mark 6) Li, H., Smith, S. E., Holloway, R. E., & Smith, F. (2006). Arbuscular Mycorrhizal Fungi Contribute to Phosphorus Uptake by Wheat Grown in a Phosphorus-Fixing Soil Even in the Absence of Positive Growth Responses. New Phytologist, (3), 536. doi:10.2307/4131237

Mark 7) Vladimir, K., & Marcel, B. (2005). Symbiotic phosphate transport in arbuscular mycorrhizas. Trends In Plant Science, 1022-29. doi:10.1016/j.tplants.2004.12.003

Jugraj 8) Oksanen I., I (2006). "Ecological and biotechnological aspects of lichens". Applied Microbiology and Biotechnology

Jugraj 9) Odling-Smee F. J., Laland K. N. & Feldman M. W. (2003). "Niche Construction: The Neglected Process in Evolution

Randa 10)Dickinson, C. H. and G. J. F. Pugh. 1974. Biology of plant litter decomposition. 2 volumes. Academic Press, New York.

Randa 11)Mason, C. F. 1976. Decomposition. Edward Arnold Publ. Ltd, Southampton.

randa 12)Beever, Ross E., and others. ‘The hidden kingdoms: fungi, lichens and some bacteria.’ In Waitakere Ranges, edited by Bruce Harvey and Trixie Harvey, 102–113. Waitakere City: Waitakere Ranges Protection Society, 2006.

Mark 13) Harrison, M. J., Dewbre, G. R., & Liu, J. (2002). A Phosphate Transporter from Medicago truncatula Involved in the Acquisition of Phosphate Released by Arbuscular Mycorrhizal Fungi. The Plant Cell October 2002 vol. 14 no. 10 2413-2429 doi: http://dx.doi.org/10.1105/tpc.004861

Mark 14) Parniske, M., (2004). Molecular genetics of the arbuscular mycorrhizal symbiosis. Current Opinion in Plant Biology Volume 7, Issue 4, August 2004, Pages 414–421 Accessed from http://www.sciencedirect.com/science/article/pii/S1369526604000779 doi: http://dx.doi.org/10.1016/j.pbi.2004.05.011

Retrieved from "https://kumu.brocku.ca/BIOL_2P96_Jan_2013-group09/Main_Page"

 Many Fungi Decomposers use their physical form and enzyme capabilities and metabolism to help decay dead animals and plant remains in the  soil. some famous fungi decomposers are :
 *Zygomycetes: The only saprotrophic zygomyces are found in the mucorales. most of these mucorals re specialized in breaking down starh, fats and proteins, extracellular enzymes such as lipases and proteases are produced during decomposition. the mucolars ability to decompose depends on the proper substrate that can be used bu them and soon to exhausted(REFRENCE :BEEVER ROSS,E 2006)
-.
 *Basidiomycetes: The saprotophic species of basidiomycetes are the parts adapted morphologically and biochemically to live on cellulose and lignocellulose. basidiomycetes are types of fungi that are able to degrade lignin, and with the help of ants and beetles thses fungi are able to remove woody remains from the ecosystem (REFRENCE :BEEVER ROSS,E 2006)