Mrakia frigida

Last updated

Mrakia frigida
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Tremellomycetes
Order: Cystofilobasidiales
Family: Mrakiaceae
Genus: Mrakia
Species:
M. frigida
Binomial name
Mrakia frigida
(Fell, Statzell, I.L. Hunter & Phaff) Y. Yamada & Komag. (1987) [1]
Synonyms

Candida frigida
Leucosporidium frigidum
Candida gelida
Leucosporidium gelidum
Mrakia gelida
Candida nivalis
Leucosporidium nivale
Mrakia nivalis
Leucosporidium stokesii
Mrakia stokesii

Contents

Mrakia frigida is a species of fungus in the order Cystofilobasidiales. [2] The species occurs in both a yeast and hyphal state, the latter producing teliospores from which basidia emerge. [3] [1] It was originally isolated in its yeast state from Antarctic snow. [4]

Growth temperature

Mrakia frigida has been classified as an obligate psychrophile since it grows well at subzero temperatures and is unable to grow at temperatures above 18–20 °C (64–68 °F). Mrakia frigida grows at −2–20 °C (28–68 °F). [5] Rapid growth of Mrakia frigida occurs at 17 °C (63 °F), and slight increase in temperature results in growth decrease. [6] Its maximum growth temperature is 19–20 °C (66–68 °F) when glucose is used as carbon source and 17–18 °C (63–64 °F) when ethanol is used. [5] The growth rate of Mrakia frigida on glucose as substrate for a given temperature is higher than that on ethanol. The cell yield of Mrakia frigida is maximum at subzero temperatures.

Membrane lipid composition

There is a positive correlation between the growth temperature and the degree of fatty-acid unsaturation of the cell lipids of Mrakia frigida. [5] The variation in the degree of fatty acid unsaturation of the yeast indicates its ability to alter the cellular component is fundamental to adaptation to environmental changes. The extent to such ability determines the growth temperature limits of Mrakia frigida. The lower limit is the point at which its membrane lipids solidify and the upper limit is the point at which its membrane lipids melt.

Cytochrome concentration

Mrakia frigida shows absorption bands at room temperature characteristic of cytochromes aa3, b and c. [6] The concentration to the cytochromes in Mrakia frigida is negatively related to its membrane-lipid unsaturation rate. At the maximum growth temperatures when the degree of lipid unsaturation of the cell membrane is high, the final cell yield is less than at lower temperatures when membrane-lipid unsaturation rate is low. This indicates glucose repression of cytochrome synthesis occurs at high degree of lipid unsaturation. However, a high concentration of cytochrome c is observed at the maximum growth temperatures of Mrakia frigida. This phenomenon may be an attempt by the cells to compensate for the decrease in cytochrome a+a3 by involving alternative pathways of electron transport.

Functions of cellular membranes

The positive correlation relationship between the growth temperature of Mrakia frigida and the membrane-lipid unsaturation rate, and the negative relationship between the membrane-lipid unsaturation rate and cytochrome concentration in cells indicate the membrane structure and composition are significant to temperature adaptation in Mrakia frigida. Manipulation of the fatty-acid unsaturation index allows Mrakia frigida to alter its membrane fluidity, and function with changing temperatures.

Related Research Articles

<span class="mw-page-title-main">Acetyl-CoA</span> Chemical compound

Acetyl-CoA is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle to be oxidized for energy production.

An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.

A hyperthermophile is an organism that thrives in extremely hot environments—from 60 °C (140 °F) upwards. An optimal temperature for the existence of hyperthermophiles is often above 80 °C (176 °F). Hyperthermophiles are often within the domain Archaea, although some bacteria are also able to tolerate extreme temperatures. Some of these bacteria are able to live at temperatures greater than 100 °C, deep in the ocean where high pressures increase the boiling point of water. Many hyperthermophiles are also able to withstand other environmental extremes, such as high acidity or high radiation levels. Hyperthermophiles are a subset of extremophiles. Their existence may support the possibility of extraterrestrial life, showing that life can thrive in environmental extremes.

<span class="mw-page-title-main">Psychrophile</span> Organism capable of growing and reproducing in the cold

Psychrophiles or cryophiles are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C (−4 °F) to 20 °C (68 °F). They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures. Psychrophile is Greek for 'cold-loving', from Ancient Greek ψυχρός (psukhrós) 'cold, frozen'.

Fructilactobacillus sanfranciscensis is a heterofermentative species of lactic acid bacteria which, through the production mainly of lactic and acetic acids, helps give sourdough bread its characteristic taste. It is named after San Francisco, where sourdough was found to contain the variety, though it is dominant in Type I sourdoughs globally. In fact, F. sanfranciscensis has been used in sourdough breads for thousands of years, and is used in 3 million tons of sourdough goods yearly.

A piezophile is an organism with optimal growth under high hydrostatic pressure i.e. an organism that has its maximum rate of growth at a hydrostatic pressure equal to or above 10 MPa, when tested over all permissible temperatures. Originally, the term barophile was used for these organisms, but since the prefix "baro-" stands for weight, the term piezophile was given preference. Like all definitions of extremophiles, the definition of piezophiles is anthropocentric, and humans consider that moderate values for hydrostatic pressure are those around 1 atm, whereas those "extreme" pressures are the normal living conditions for those organisms. Hyperpiezophiles are organisms that have their maximum growth rate above 50 MPa.

<i>Zygosaccharomyces bailii</i> Species of fungus

Zygosaccharomyces bailii is a species in the genus Zygosaccharomyces. It was initially described as Saccharomyces bailii by Lindner in 1895, but in 1983 it was reclassified as Zygosaccharomyces bailii in the work by Barnett et al.

In biochemistry, fatty acid synthesis is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases. This process takes place in the cytoplasm of the cell. Most of the acetyl-CoA which is converted into fatty acids is derived from carbohydrates via the glycolytic pathway. The glycolytic pathway also provides the glycerol with which three fatty acids can combine to form triglycerides, the final product of the lipogenic process. When only two fatty acids combine with glycerol and the third alcohol group is phosphorylated with a group such as phosphatidylcholine, a phospholipid is formed. Phospholipids form the bulk of the lipid bilayers that make up cell membranes and surrounds the organelles within the cells. In addition to cytosolic fatty acid synthesis, there is also mitochondrial fatty acid synthesis (mtFASII), in which malonyl-CoA is formed from malonic acid with the help of malonyl-CoA synthetase (ACSF3), which then becomes the final product octanoyl-ACP (C8) via further intermediate steps.

Long-chain alcohol oxidase is one of two enzyme classes that oxidize long-chain or fatty alcohols to aldehydes. It has been found in certain Candida yeast, where it participates in omega oxidation of fatty acids to produce acyl-CoA for energy or industrial use, as well as in other fungi, plants, and bacteria.

Yarrowia is a fungal genus in the family Dipodascaceae. For a while the genus was monotypic, containing the single species Yarrowia lipolytica, a yeast that can use unusual carbon sources, such as hydrocarbons. This has made it of interest for use in industrial microbiology, especially for the production of specialty lipids. Molecular phylogenetics analysis has revealed several other species that have since been added to the genus.

<i>Nannochloropsis</i> and biofuels

Nannochloropsis is a genus of alga within the heterokont line of eukaryotes, that is being investigated for biofuel production. One marine Nannochloropsis species has been shown to be suitable for algal biofuel production due to its ease of growth and high oil content, mainly unsaturated fatty acids and a significant percentage of palmitic acid. It also contains enough unsaturated fatty acid linolenic acid and polyunsaturated acid for a quality biodiesel.

<span class="mw-page-title-main">Cell membrane</span> Biological membrane that separates the interior of a cell from its outside environment

The cell membrane is a biological membrane that separates and protects the interior of a cell from the outside environment. The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic molecules. In addition, cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity, and cell signalling and serve as the attachment surface for several extracellular structures, including the cell wall and the carbohydrate layer called the glycocalyx, as well as the intracellular network of protein fibers called the cytoskeleton. In the field of synthetic biology, cell membranes can be artificially reassembled.

Single cell oil, also known as Microbial oil consists of the intracellular storage lipids, triacyglycerols. It is similar to vegetable oil, another biologically produced oil. They are produced by oleaginous microorganisms, which is the term for those bacteria, molds, algae and yeast, which can accumulate 20% to 80% lipids of their biomass. The accumulation of lipids take place by the end of logarithmic phase and continues during station phase until carbon source begins to reduce with nutrition limitation.

The Leucosporidiales are an order of fungi in the class Microbotryomycetes. The order contains a single family, the Leucosporidiaceae, which in turn contains a single genus, Leucosporidium. The order comprises fungi that are mostly known from their yeast states, though some produce hyphal states in culture that give rise to teliospores from which auricularioid basidia emerge.

Omega-7 fatty acids are a class of unsaturated fatty acids in which the site of unsaturation is seven carbon atoms from the end of the carbon chain. The two most common omega-7 fatty acids in nature are palmitoleic acid and vaccenic acid. They are widely used in cosmetics due to their moisturizing properties. Omega-7 fats are not essential fatty acids in humans as they can be made endogenously. Diets rich in omega-7 fatty acids have been shown to have beneficial health effects, such as increasing levels of HDL cholesterol and lowering levels of LDL cholesterol.

Leucosporidium is a genus of fungi in the subdivision Pucciniomycotina. The genus comprises fungi that are mostly known from their yeast states, though some produce hyphal states in culture that give rise to teliospores from which auricularioid basidia emerge. Species known only from their anamorphic yeast states were formerly referred to the genus Leucosporidiella, but, following changes to the International Code of Nomenclature for algae, fungi, and plants, the practice of giving different names to teleomorph and anamorph forms of the same fungus was discontinued, meaning that Leucosporidiella became a synonym of the earlier name Leucosporidium. Species have been isolated predominantly from cold environments and are regarded as psychrotolerant.

Shewanella violacea DSS12 is a gram-negative bacterium located in marine sediment in the Ryukyu Trench at a depth of 5,110m. The first description of this organism was published in 1998 by Japanese microbiologists Yuichi Nogi, Chiaki Kato, and Koki Horikoshi, who named the species after its violet appearance when it is grown on Marine Agar 2216 Plates.

Deinococcus frigens is a species of low temperature and drought-tolerating, UV-resistant bacteria from Antarctica. It is Gram-positive, non-motile and coccoid-shaped. Its type strain is AA-692. Individual Deinococcus frigens range in size from 0.9-2.0 μm and colonies appear orange or pink in color. Liquid-grown cells viewed using phase-contrast light microscopy and transmission electron microscopy on agar-coated slides show that isolated D. frigens appear to produce buds. Comparison of the genomes of Deiococcus radiodurans and D. frigens have predicted that no flagellar assembly exists in D. frigens.

<i>Candida tropicalis</i> Species of fungus

Candida tropicalis is a species of yeast in the genus Candida. It is a common pathogen in neutropenic hosts, in whom it may spread through the bloodstream to peripheral organs. For invasive disease, treatments include amphotericin B, echinocandins, or extended-spectrum triazole antifungals.

Blastobotrys elegans is a species of fungus.

References

  1. 1 2 Yamada Y, Komagata K (1987). "Mrakia gen. nov., a heterobasidiomycetous yeast genus for the Q8-equipped, self-sporulating organisms which produce a unicellular metabasidium, formerly classified in the genus Leucosporidium". J Gen Appl Microbiol. 33: 455–457.
  2. Liu XZ, Wang QM, Göker M, Groenewald M, Kachalkin AV, Lumbsch HT, Millanes AM, Wedin M, Yurkov AM, Boekhout T, Bai FY (2015). "Towards an integrated phylogenetic classification of the Tremellomycetes". Studies in Mycology. 81: 85–147. doi: 10.1016/j.simyco.2015.12.001 . PMC   4777781 .
  3. Fell JW, Statzell AC, Hunter IL, Phaff HJ (1969). "Leucosporidium gen. n., the heterobasidiomycetous stage of several yeasts of the genus Candida". Antonie van Leeuwenhoek. 35 (4): 433–462. doi:10.1007/bf02219163.
  4. di Menna ME (1966). "Three new yeasts from Antarctic soils: Candida nivalis, Candida gelida and Candida frigida spp.n.". Antonie van Leeuwenhoek. 32: 25–28. doi:10.1007/BF02097442.
  5. 1 2 3 K. Watson, Helen Arthur & W. A. Shipton (1976). "Leucosporidium yeasts: obligate psychrophiles which alter membrane-lipid and cytochrome composition with temperature". Microbiology . 97 (1): 11–18. doi: 10.1099/00221287-97-1-11 . PMID   993782.
  6. 1 2 H. Arthur & K. Watson (1976). "Thermal adaptation in yeast: growth temperatures, membrane lipid, and cytochrome composition of psychrophilic, mesophilic, and thermophilic yeasts". Journal of Bacteriology . 128 (1): 56–68. doi:10.1128/jb.128.1.56-68.1976. PMC   232826 . PMID   988016.