Chloroflexus aurantiacus: Difference between revisions - Wikipedia


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{{Short description|Species of bacterium}}

{{italic title}}

{{speciesbox

{{Taxobox

| nametaxon = ''Chloroflexus aurantiacus''

| authority = Pierson and Castenholz 1974<ref>{{cite journal|last1=Parte|first1=A.C.|title=Chloroflexus|website=[[LPSN]]|url=https://lpsn.dsmz.de/genus/chloroflexus}}</ref>

| image =

| image_caption = ''Chloroflexus aurantiacus''

| regnum = [[Bacteria]]

| divisio = [[Chloroflexi (phylum)|Chloroflexi]]

| classis = [[Chloroflexi (phylum)|Chloroflexi]]

| ordo = [[Chloroflexales]]

| familia = [[Chloroflexaceae]]

| genus = [[Chloroflexus]]

| species = '''''C. aurantiacus'''''

| binomial = ''Chloroflexus aurantiacus''

}}

[[File:Algae on left bacteria on right at Norris Geyser Basin in Yellowstone.JPG|thumb|250px|Thermophilic Organisms]]

'''''Chloroflexus aurantiacus''''' is a [[Photosynthesis|photosynthetic]] [[bacterium]] isolated from hot springs, belonging to the [[Chloroflexi (phylum)Chloroflexota|green non-sulfur bacteria]]. This organism is [[Thermophile|thermophilic]] and can grow at temperatures from {{convert|35&nbsp;°C |to |70&nbsp;°|C|F}}. ''Chloroflexus aurantiacus'' can survive in the dark if [[oxygen]] is available. When grown in the dark, ''Chloroflexus aurantiacus'' has a dark orange color. When grown in sunlight it is dark green. The individual bacteria tend to form filamentous colonies enclosed in sheaths, which are known as [[trichomes]].

==Physiology==

As a genus, ''Chloroflexus'' spp. are [[gram negative]] filamentous anoxygenic phototrophic (FAP) organisms that utilize [[photosystem II|type II]] photosynthetic reaction centers containing [[bacteriochlorophyll]] ''a'' similar to the [[purple bacteria]], and light-harvesting [[chlorosome]]s containing bacteriochlorophyll ''c'' similar to [[green sulfur bacteria]] of the ''Chlorobi[[Chlorobiota]]''. Like other members of its phylum (''cf.'' [[Chloroflexota]]), the species stains [[Gram negative]], yet has a single lipid layer (monoderm),<ref>{{Cite journal | last1 = Sutcliffe | first1 = I. C. | title = A phylum level perspective on bacterial cell envelope architecture | doi = 10.1016/j.tim.2010.06.005 | journal = Trends in Microbiology | volume = 18 | issue = 10 | pages = 464–470 | year = 2010 | pmid = 20637628}}</ref> but with thin [[peptidoglycan]], which is compensated for by [[S-layer|S-layer protein]].

As the name implies, these anoxygenic phototrophs do not produce oxygen as a byproduct of photosynthesis, in contrast to oxygenic phototrophs such as [[cyanobacteria]], [[algae]], and higher [[plants]]. While oxygenic phototrophs use [[water]] as an [[electron donor]] for phototrophy, ''Chloroflexus'' uses reduced sulfur compounds such as [[hydrogen sulfide]], [[thiosulfate]], or elemental sulfur. This belies their antiquatedobsolescent name '''green non-sulfur bacteria''',; however, ''Chloroflexus'' spp. can also utilize [[hydrogen]](H<sub>2</sub>) as a source of electrons.

''Chloroflexus aurantiacus'' is thought to grow [[photoheterotroph]]ically in nature, but it has the capability of fixing inorganic carbon through [[photoautotroph]]ic growth. Instead of using the [[Calvin cycle|Calvin-Benson-Bassham Cycle]] typical of plants, ''Chloroflexus aurantiacus'' has been demonstrated to use a novelan autotrophic pathway known as the [[3-Hydroxypropionate pathway]].

The complete [[electron transport chain]] for ''Chloroflexus'' spp. is not yet known. Particularly, ''Chloroflexus aurantiacus'' has not been demonstrated to have a [[cytochrome bc1 complex|cytochrome ''bc<sub>1</sub>'' complex]], and may use different proteins to reduce [[cytochrome c|cytochrome ''c'']].

==Evolution of photosynthesis==

One of the main reasons for interest in ''Chloroflexus aurantiacus'' is in the study of the evolution of photosynthesis. As terrestrial mammals, we are most familiar with photosynthetic plants such as trees. However, photosynthetic eukaryotes are a relatively recent evolutionary development. Photosynthesis by eukaryotic organisms can be traced back to [[Endosymbiosis|endosymbiotic]] events in which non-photosynthetic [[eukaryote]]s internalized photosynthetic organisms. The [[chloroplast]]s of trees still retain their own DNA as a molecular remnant that indicated their origin as [[Photosynthesis|photosynthetic]] [[bacteria]].

===The "respiration early" hypothesis===

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==See also==

*[[Chloroflexota]]

*[[Chloroflexi (phylum)|Chloroflexi]]

*[[endosymbiotic theory]]

==References==

{{Reflist}}

#{{cite journal |vauthors=Pierson BK, Castenholz RW |title=A phototrophic gliding filamentous bacterium of hot springs, ''Chloroflexus aurantiacus'', gen. and sp. nov |journal=Arch. Microbiol. |volume=100 |issue=1 |pages=5–24 |year=1974 |pmid=4374148 |doi=10.1007/BF00446302 }}

#{{cite journal |vauthors=Oelze J, Fuller RC |title=Temperature dependence of growth and membrane-bound activities of ''Chloroflexus aurantiacus'' energy metabolism |journal=J. Bacteriol. |volume=155 |issue=1 |pages=90–6 |date=1 July 1983|pmid=6863222 |pmc=217656 |url=http://jb.asm.org/cgi/pmidlookup?view=long&pmid=6863222 }}

#{{cite journal|author2-link=Lucas Andrew Staehelin|vauthors=Sprague SG, Staehelin LA, DiBartolomeis MJ, Fuller RC |title=Isolation and development of chlorosomes in the green bacterium ''Chloroflexus aurantiacus'' |journal=J. Bacteriol. |volume=147 |issue=3 |pages=1021–31 |date=1 September 1981|pmid=7275928 |pmc=216142 |url=http://jb.asm.org/cgi/pmidlookup?view=long&pmid=7275928 }}

#{{cite journal |vauthors=Xiong J, Bauer CE |title=A cytochrome b origin of photosynthetic reaction centers: an evolutionary link between respiration and photosynthesis |journal=J. Mol. Biol. |volume=322 |issue=5 |pages=1025–37 |date=October 2002 |pmid=12367526 |url=http://linkinghub.elsevier.com/retrieve/pii/S0022283602008227 |doi=10.1016/S0022-2836(02)00822-7}}

#{{cite journal |author=Beanland TJ |title=Evolutionary relationships between "Q-type" photosynthetic reaction centres: hypothesis-testing using parsimony |journal=J. Theor. Biol. |volume=145 |issue=4 |pages=535–45 |date=August 1990 |pmid=2246901 |doi=10.1016/S0022-5193(05)80487-4 }}

#{{cite journal |vauthors=Castresana J, Saraste M |title=Evolution of energetic metabolism: the respiration-early hypothesis |journal=Trends Biochem. Sci. |volume=20 |issue=11 |pages=443–8 |date=November 1995 |pmid=8578586 |url=http://linkinghub.elsevier.com/retrieve/pii/S0968000400890982 |doi=10.1016/S0968-0004(00)89098-2}}

== Further reading ==

* {{cite journal|last1=Bina|first1=David|last2=Gardian|first2=Zdenko|last3=Vacha|first3=Frantisek|last4=Litvin|first4=Radek|title=Supramolecular organization of photosynthetic membrane proteins in the chlorosome-containing bacterium ''Chloroflexus aurantiacus'' |journal=Photosynthesis Research|date=October 2014|volume=122|issue=1|pages=13–21|doi=10.1007/s11120-014-0006-8|pmid=24760483}}

* {{cite journal|last1=Gao|first1=Xinliu|last2=Majumder|first2=Erica Wunderlich|last3=Kang|first3=Yisheng|last4=Yue|first4=Hai|author5-link=Robert E. Blankenship|last5=Blankenship|first5=Robert E.|title=Functional analysis and expression of the mono-heme containing cytochrome c subunit of alternative complex III in ''Chloroflexus aurantiacus'' |journal=Archives of Biochemistry and Biophysics|date= 15 July 2013|volume=535|issue=2|pages=197–204|doi=10.1016/j.abb.2013.04.002|pmid=23587789}}

==External links==

*[http://bacdive.dsmz.de/index.php?search=2417&submit=Search Type strain of ''Chloroflexus aurantiacus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase]

{{Taxonbar|from=Q2473850}}

[[Category:Phototrophic bacteria]]

[[Category:Bacteria described in 1974]]

[[Category:Chloroflexota]]