saprobe

腐生菌

WordNet

an organism that lives in and derives its nourishment from organic matter in stagnant or foul water

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/07/10 12:21:01」(JST)

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Mycelial cord made up of a collection of hyphae; an essential part in the process of saprotrophic nutrition, it is used for the intake of organic matter through its cell wall. The network of hyphae is referred to as a mycelium, which is fundamental to fungal nutrition.

Saprotrophic nutrition /sæprəˈtrɒfɪk, -proʊ-/^[1] or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of dead or decayed organic matter. It occurs in saprotrophs or heterotrophs, and is most often associated with fungi (for example Mucor) and soil bacteria. Saprotrophic microscopic fungi are sometimes called saprobes; saprotrophic plants or bacterial flora are called saprophytes (sapro- + -phyte, "rotten material" + "plant"). The process is most often facilitated through the active transport of such materials through endocytosis within the internal mycelium and its constituent hyphae.^[2]

Various word roots relating to decayed matter (detritus, sapro-), eating and nutrition (-vore, -phage), and plants or life forms (-phyte, -obe) produce various terms, such as detritivore, detritophage, saprotroph, saprophyte, saprophage, and saprobe; their meanings overlap, although technical distinctions (based on physiologic mechanisms) narrow the senses. For example, usage distinctions can be made based on macroscopic swallowing of detritus (as an earthworm does) versus microscopic lysis of detritus (as a mushroom does).

A facultative saprophyte appears on stressed or dying plants and may combine with the live pathogens.^{[citation needed]}

Process

As matter decomposes within a medium in which a saprotroph is residing, the saprotroph breaks such matter down into its composites.

Proteins are broken down into their amino acid composites through the breaking of peptide bonds by proteases.^[3]
Lipids are broken down into fatty acids and glycerol by lipases.^[3]
Starch is broken down into pieces of simple disaccharides by amylases.^[3]

These products are re-absorbed into the hypha through the cell wall via endocytosis and passed on throughout the mycelium complex. This facilitates the passage of such materials throughout the organism and allows for growth and, if necessary, repair.^[2]

Conditions

In order for a saprotrophic organism to facilitate optimal growth and repair, favourable conditions and nutrients must be present.^[4] Optimal conditions refers to several conditions which optimise the growth of saprotrophic organisms, such as;

Presence of water: 80–90% of the fungi is composed of water by mass, and requires excess water for absorption due to the evaporation of internally retent water.^[4]
Presence of oxygen: Very few saprotrophic organisms can endure anaerobic conditions as evidenced by their growth above media such as water or soil.^[4]
Neutral-acidic pH: The condition of neutral or mildly acidic conditions under pH 7 are required. ^[4]
Low-medium temperature: The majority of saprotrophic organisms require temperatures between 1 °C and 35 °C, with optimum growth occurring at 25 °C.^[4]

The majority of nutrients taken in by such organisms must be able to provide carbon, proteins, vitamins and in some cases, ions. Due to the carbon composition of the majority of organisms, dead and organic matter provide rich sources of disaccharides and polysaccharides such as maltose and starch, and of the monosaccharide glucose.^[2]

In terms of nitrogen-rich sources, saprotrophs require combined protein for the creation of proteins, which is facilitated by the absorption of amino acids, and usually taken from rich soil. Although both ions and vitamins are rare, thiamine or ions such as potassium, phosphorus, and magnesium aid the growth of the mycelium.^[2]

Notes

Clegg, C. J.; Mackean, D. G. (2006). Advanced Biology: Principles and Applications, 2nd ed. Hodder Publishing
Zmitrovich, I. V.; Wasser, S. P.; Ţura D. (2014). Wood-inhabiting fungi Fungi from different substrates / J. K. Misra, J. P. Tewari, S. K. Deshmukh, C. Vágvölgyi (eds). N. Y.: CRC Press, Taylor and Francis group, 2014. P. 17–74. (http://media.wix.com/ugd/b65817_2690a71af41f4486863a9b220827d7b5.pdf)

References

^ "saprotroph - definition of saprotroph in English from the Oxford dictionary". OxfordDictionaries.com. Retrieved 2016-01-20.
^ ^a ^b ^c ^d Advanced biology principles, p 296—states the purpose of saprotrophs and their internal nutrition, as well as the main two types of fungi that are most often referred to, as well as describes, visually, the process of saprotrophic nutrition through a diagram of hyphae, referring to the Rhizobium on damp, stale whole-meal bread or rotting fruit.
^ ^a ^b ^c Advanced Biology Principles, p296, fig 14.16—Diagram detailing the re-absorption of substrates within the hypha.
^ ^a ^b ^c ^d ^e Advanced Biology Principles, p296 fig 14.17—A diagram explaining the optimal conditions needed for successful growth and repair.

An organism, especially a fungus or bacterium, that derives its nourishment from dead or decaying organic matter. Also called saprobe.

English Journal

Fungal denitrification: Bipolaris sorokiniana exclusively denitrifies inorganic nitrogen in the presence and absence of oxygen.

Phillips R1, Grelet G2, McMillan A2, Song B3, Weir B2, Palmada T2, Tobias C4.
FEMS microbiology letters.FEMS Microbiol Lett.2016 Feb;363(4). pii: fnw007. doi: 10.1093/femsle/fnw007. Epub 2016 Jan 12.
Fungi may play an important role in the production of the greenhouse gas nitrous oxide (N2O). Bipolaris sorokiniana is a ubiquitous saprobe found in soils worldwide, yet denitrification by this fungal strain has not previously been reported. We aimed to test if B. sorokiniana would produce N2O and C
PMID 26764425

Mutant characterization and in vivo conditional repression identify aromatic amino acid biosynthesis to be essential for Aspergillus fumigatus virulence.

Sasse A1, Hamer SN1,2, Amich J3, Binder J4, Krappmann S1,4,5.
Virulence.Virulence.2016;7(1):56-62. doi: 10.1080/21505594.2015.1109766. Epub 2015 Nov 25.
Pathogenicity of the saprobe Aspergillus fumigatus strictly depends on nutrient acquisition during infection, as fungal growth determines colonisation and invasion of a susceptible host. Primary metabolism has to be considered as a valid target for antimycotic therapy, based on the fact that several
PMID 26605426

Comparative Transcriptome Analysis of the Cosmopolitan Marine Fungus Corollospora maritima Under Two Physiological Conditions.

Velez P1, Alejandri-Ramírez ND2, González MC3, Estrada KJ4, Sanchez-Flores A4, Dinkova TD5.
G3 (Bethesda, Md.).G3 (Bethesda).2015 Jun 26;5(9):1805-14. doi: 10.1534/g3.115.019620.
Marine sandy beaches represent dynamic environments often subject to harsh conditions and climate fluctuations, where natural and anthropogenic inputs of freshwater from fluvial and pluvial sources alter salinity, which has been recognized as a key variable affecting the distribution of aquatic orga
PMID 26116293

Japanese Journal

Lindgomyces angustiascus, (Lindgomycetaceae, Pleosporales, Dothideomycetes), a new lignicolous species from freshwater habitats in the USA

Raja Huzefa A.,Oberlies Nicholas H.,El-Elimat Tamam [他]
Mycoscience : official journal of the Mycological Society of Japan 54(5), 353-361, 2013-09
NAID 40019780776