Rhodospirillum rubrum: Difference between revisions

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==Description and significance==
==Description and significance==
DOES NOT infect humans or animals


Mesophile, optimum temperature 25-30 C
''Rhodospirillum rubrum'' is a Gram-negative, mesophilic proteobacteria. It has multilayered outer envelopes, which contain mostly unsaturated, but some saturated fats in its cell wall. Its optimal growth temperature is 25-30 C. R. rubrum is a spirilla, meaning it has a spiral-shape. It is polarly flagellated, and therefore motile. Its length is 3-10 um, with a width of 08-1.0 um.
Gram-negative, mostly unsaturated, some saturated fats in cell wall


Has multilayered outer envelops


Complex pigments call “Carotenoid” and “BacteriocholophyII” are found in relatively large particles called “Chromatophores” which gives the bacteria it’s distinctive color.  
''R. rubrum'' is a facultative anaerobe. It can undergo alcoholic fermentation or aerobic respiration. It contains carotenoid and bateriochlorophyll, found in its chromatophore particles, giving it its distinct purple-red color. The purple-red color is apparent under anaerobic conditions, while ''R. rubrum'' is colorless under aerobic conditions (i.e. photosynthesis). Carotenoids are found to help in light absorption during photosynthesis, and were discovered in investigation of ''R. rubrum'''s cytoplasmic membrane. Electron microscopy has revealed that the chromatopohore of ''R. rubrum''is a flattened disk
Electron microscopy revel that the “Chromatophore” are flatten disk
Purple colored under anaerobic conditions, Colorless in aerobic


Carotenoids give purple-red color


they help in light absorption for photosynthesis
Although photosynthesis is active under aerobic conditions, it is generally suppressed in the presence of O2. Sulfur is a major byproduct of photosynthesis, not O2. With that said, ''R. rubrum'' can grow heterotrophically, or autotrophically  when photosynthetic. It oxidizes carbon monoxide (CO), and can use sulfide at low concentrations as an electron donor in carbon dioxide reduction. Unlike many plants, ''R. rubrum'' contains no chlorophyll a (absorption spectra 430-662 nm). However, it does contain chlorophyll b (absorption spectra 660-680 nm) and bacteriochlorophylls (800-925 nm). This allows it to utilize more energy from the electromagnetic spectra.
           
                                                                               
''R. rubrum'' is commonly found in mud, pond water, and sewage. It has not been found to infect humans or animals. It is a nitrogen fixing bacteria, which converts atmospheric nitrogen gas to ammonia: N2 –-(nitrogenase)--> NH4+.


Found in invaginations of the cytoplasmic membrane


Polarly Flagellated
There are several applications of ''R. rubrum'' in the field of biotechnology. It is a model system of light to chemical energy conversion and for its nitrogen fixing pathways. It is also the subject of radiation resistance studies. It can be used in several ways for consumption, as well. The proteobacteria may be a source of animal food and agricultural fertilizer. Another important role in research includes the production of vitamins. It is also being researched for its production of biological plastic from precursors of poly-hydroxy-butric-acid. ''R. rubrum'' may also be a contributor in biological hydrogen fuels, mainly through its evolution of the enzyme nitrogenase.
Spiralla
Length 3-10 um, Width 0.8-1.0 um
Facultative anaerobe
 
Can use alcoholic fermentation or aerobic respiration
 
Photosynthesis is active under anaerobic conditions, but is genetically suppressed in the presence of O2
 
O2 is not a byproduct of photosynthesis, sulfur is
 
Can grow autotrophically or heterotrophically when phototrophic
 
Oxidizes carbon monoxide
 
Can use sulfide (AT LOW CONCENTRATIONS) as an electron donor in CO2 reduction
 
Contains no chlorophyll a (absorption spectra 430-662)
 
contains chlorphyll b (absorption spectra 660-680 nm) and bacteriochlorophylls (800-925 nm)
 
advantageous to use more energy of electromagnetic spectra
 
Nitrogen fixing bacteria
 
Converts atmospheric nitrogen gas to ammonia
 
N2 --(nitrogenase)--> NH4+
 
Biotech uses
 
Consumption
 
Biological plastic production from precursors of poly-hydroxy-butric-acid
 
Biological hydrogen fuel (evolution of nitrogenase)
 
Academia
 
Model system of light to chemical energy conversion and for nitrogen fixation pathways
 
Subject of radiation resistance studies
 
Cell free systems including photosynthesis and ATP synthesis
 
These bacteria are often used for sewage treatment, agricultural fertilizer, or molecular hydrogen production. Rhodospirillum Rubrum is also often used in the production of animal food or vitamins.


==Genome structure==
==Genome structure==

Revision as of 17:36, 18 October 2011

This student page has not been curated.

A Microbial Biorealm page on the genus Rhodospirillum rubrum

Classification

Higher order taxa

Kingdom: Bacteria
Phylum: Proteobacteria
Class: Alphaproteobacteria
Order: Rhodospirillales
Family: Rhodospirillaceae
Genus: Rhodospirillum

Species

Rhodospirillum rubrum

NEUF2011

Description and significance

Rhodospirillum rubrum is a Gram-negative, mesophilic proteobacteria. It has multilayered outer envelopes, which contain mostly unsaturated, but some saturated fats in its cell wall. Its optimal growth temperature is 25-30 C. R. rubrum is a spirilla, meaning it has a spiral-shape. It is polarly flagellated, and therefore motile. Its length is 3-10 um, with a width of 08-1.0 um.


R. rubrum is a facultative anaerobe. It can undergo alcoholic fermentation or aerobic respiration. It contains carotenoid and bateriochlorophyll, found in its chromatophore particles, giving it its distinct purple-red color. The purple-red color is apparent under anaerobic conditions, while R. rubrum is colorless under aerobic conditions (i.e. photosynthesis). Carotenoids are found to help in light absorption during photosynthesis, and were discovered in investigation of R. rubrum's cytoplasmic membrane. Electron microscopy has revealed that the chromatopohore of R. rubrumis a flattened disk.


Although photosynthesis is active under aerobic conditions, it is generally suppressed in the presence of O2. Sulfur is a major byproduct of photosynthesis, not O2. With that said, R. rubrum can grow heterotrophically, or autotrophically when photosynthetic. It oxidizes carbon monoxide (CO), and can use sulfide at low concentrations as an electron donor in carbon dioxide reduction. Unlike many plants, R. rubrum contains no chlorophyll a (absorption spectra 430-662 nm). However, it does contain chlorophyll b (absorption spectra 660-680 nm) and bacteriochlorophylls (800-925 nm). This allows it to utilize more energy from the electromagnetic spectra.


R. rubrum is commonly found in mud, pond water, and sewage. It has not been found to infect humans or animals. It is a nitrogen fixing bacteria, which converts atmospheric nitrogen gas to ammonia: N2 –-(nitrogenase)--> NH4+.


There are several applications of R. rubrum in the field of biotechnology. It is a model system of light to chemical energy conversion and for its nitrogen fixing pathways. It is also the subject of radiation resistance studies. It can be used in several ways for consumption, as well. The proteobacteria may be a source of animal food and agricultural fertilizer. Another important role in research includes the production of vitamins. It is also being researched for its production of biological plastic from precursors of poly-hydroxy-butric-acid. R. rubrum may also be a contributor in biological hydrogen fuels, mainly through its evolution of the enzyme nitrogenase.

Genome structure

Finished Circular chromosome 4,352,825 base pairs 65% GC Plasmid 53,732 bp 60% GC Total 3,850 protein coding genes 83 RNA genes

Gene breakdown 6.9% Transcription 4.6% Translation, ribosome structure, biosynthesis 4.0% Replication, recombination and repair 7.9% Signal transduction mechanisms 5.9% Cell wall, membrane biogenesis 6.6% energy production and conversion 5.0% Carbohydrate transport and metabolism 9.9% Amino acid transport and metabolism 4.7% Coenzyme transport and metabolism 3.7% Lipid transport and metabolism 6.5% Inorganic ion transport and metabolism

Ecology

Rhodospirillum Rubrum is found in many natural environments such as pond water, mud, and sewage.

Cell structure and metabolism

Interesting features of cell structure; how it gains energy; what important molecules it produces.

Basic Metabolism Versatile organism that can obtain energy through alternative mechanism.

Ex. Rhodospirillum can grow in dark chemo-tropical environment with the presence of O2 or they can grow in a photo-tropical environment without O2.

Phototrophically grown Rhodospirillum contain photosynthetic electron transport and ATP synthesis enzymes in their membrane and contain a membrane bound pyrophosphatase. Chemotrophically dark grown Rhodospirillum contain low concentration of bacteriochlorophyII and carotenoids and has no bound pyrophosphatase in their membrane.

Rhodospirillum Rubrum is found in many natural settings such as pond water, mud, or sewage.

Habitat; symbiosis; contributions to the environment.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Current Research

Some journal articles I found interesting.

1. Evidence that Ubiquinone Is a Required Intermediate for Rhodoquinone Biosynthesis in Rhodospirillum rubrum

2. Effect of Perturbation of ATP Level on the Activity and Regulation of Nitrogenase in Rhodospirillum rubrum

3. Modes of hydrogen production in the photosynthetic bacterium, Rhodospirillum rubrum

  • Renewable energy

Cool Factor

Describe something you find "cool" about this microbe.

Possible topics:

Photosynthetic, but does not have light harvesting complex 2 (LHC2), which is commonly found in many photosynthetic bacteria.

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Iris Keren