Rhodospirillum rubrum

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A Microbial Biorealm page on the genus Rhodospirillum rubrum

Higher order taxa

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

Species

Rhodospirillum rubrum

NEUF2011

Description and significance

DOES NOT infect humans or animals

Mesophile, optimum temperature 25-30 C 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. 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

Found in invaginations of the cytoplasmic membrane

Polarly Flagellated 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

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