Name: sulfur-using bacteria that harvest light
Uploaded: 2025-06-12T09:22:25.000Z
Duration: 1 min 28 s
Channel: JoVE

Zu den anoxygenen phototrophen Bakterien, die keinen Sauerstoff als Produkt der Photosynthese erzeugen, gehören violetter Schwefel, violetter Nichtschwefel, grüner Schwefel und grüne Nichtschwefelbakterien. Purpur-Schwefelbakterien gehören zu mehreren Gattungen der Klasse der Gammaproteobakterien, darunter Chromatium. Sie kommen überwiegend in schwefelreichen meromiktischen Seen vor und haben typischerweise Schwefelkörnchen in den Zellen. Im Gegensatz dazu gedeihen violette Nichtschwefelbakterien, die in Alpha- und Betaproteobakterien eingeteilt werden, in schwefelarmen Umgebungen. Eine Schlüsselgattung ist Rhodomicrobium. Beide Gruppen von Purpurbakterien haben lamelläre intrazelluläre photosynthetische Membransysteme und enthalten Bakteriochlorophyll a oder b.Grüne Schwefelbakterien gehören zum Stamm der Chlorobi. Sie enthalten bakteriochlorophyll c, d oder e, die in Chlorosomen untergebracht sind, wie bei der repräsentativen Spezies Chlorobaculum tepidum zu sehen ist. Sie gedeihen in schwefelreichen und Tiefseeumgebungen. Grüne Nichtschwefelbakterien werden in den Stamm der Chloroflexi eingeteilt. Die meisten Spezies, einschließlich Chloroflexus aurantiacus, sind filamentös und enthalten die Bakteriochlorophylle a oder c für die Photosynthese.

phototrophe bakterien

Anoxygenic Phototrophic Bacteria

Anoxygene phototrophe Bakterien sind eine vielf&#228;ltige Gruppe von Mikroorganismen, die Photosynthese ohne Sauerstoffproduktion betreiben. Sie umfassen haupts&#228;chlich Schwefelpurpurbakterien, Nichtschwefelpurpurbakterien, gr&#252;ne Schwefelbakterien und gr&#252;ne Nicht-Schwefelbakterien. Diese Bakterien werden den Linien der Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi und Chloroflexi zugeordnet, wobei jede Gruppe &#252;ber spezifische physiologische und &#246;kologische Anpassungen verf&#252;gt.
Schwefelpurpurbakterien geh&#246;ren zu den Gammaproteobacteria und gedeihen in schwefelreichen, anoxischen Umgebungen wie meromiktischen Seen, marinen Sedimenten und Salzwiesen. Sie oxidieren Schwefelwasserstoff (H_2S) als Elektronendonator f&#252;r die Photosynthese, wobei zun&#228;chst elementarer Schwefel (S_0) entsteht, der intrazellul&#228;r gespeichert wird, und sp&#228;ter zu Sulfat (SO_4^2-) weiter oxidiert wird. Repr&#228;sentative Gattungen sind Chromatium und Thiocapsa. Diese Bakterien enthalten Bakteriochlorophyll a oder b und nutzen ein Q-Typ-Photosystem zur Lichtabsorption.
Nichtschwefelpurpurbakterien, die zu Alphaproteobacteria und Betaproteobacteria geh&#246;ren, sind metabolisch vielseitig und gedeihen in Umgebungen mit geringen H_2S-Konzentrationen. Sie fungieren typischerweise als Photoheterotrophe, wobei Licht als Energiequelle und organische Verbindungen als Kohlenstoffquelle dienen, einige Arten k&#246;nnen jedoch auch photoautotroph mit H_2, niedrigem H_2S oder Fe^2+ wachsen. Auch sie besitzen Q-Typ-Photosysteme und enthalten Bakteriochlorophyll a oder b. Zu den bekannten Gattungen geh&#246;ren Rhodobacter und Rhodospirillum.
Gr&#252;ne Schwefelbakterien, die zur Gruppe der Chlorobi geh&#246;ren, sind strikt anaerobe, unbewegliche Phototrophe, die H_2S als Elektronendonator nutzen. Im Gegensatz zu Schwefelpurpurbakterien speichern sie S_0 extrazellul&#228;r und fixieren CO_2 &#252;ber den reversen Zitronens&#228;urezyklus. Sie enthalten Bakteriochlorophyll c, d oder e, das in Chlorosomen lokalisiert ist &#8211; einzigartigen lichtsammelnden Strukturen. Eine gut untersuchte Art ist Chlorobaculum tepidum, das in sulfidreichen Umgebungen mit minimaler Lichtverf&#252;gbarkeit vorkommt.
Gr&#252;ne Nicht-Schwefelbakterien, auch als filament&#246;se anoxygene Phototrophe bezeichnet, geh&#246;ren zur Gruppe der Chloroflexi. Sie wachsen prim&#228;r als Photoheterotrophe, k&#246;nnen aber auch photoautotroph mit H_2 oder H_2S wachsen. Ihr photosynthetisches System stellt eine Hybridform zwischen dem der purpurnen und gr&#252;nen Schwefelbakterien dar, indem es sowohl ein Q-Typ-Photosystem als auch Chlorosomen enth&#228;lt. Chloroflexus aurantiacus ist eine repr&#228;sentative Art, die h&#228;ufig in hei&#223;en Quellen zu finden ist. Thermomicrobium, eine verwandte nichtphototrophe Gattung, ist ein Thermophil mit ungew&#246;hnlichen Membranlipiden.
Heliobakterien sind anoxygene phototrophe grampositive Bakterien, die zum Stamm der Firmicutes geh&#246;ren. Sie besitzen ein FeS-Typ-Photosystem und produzieren als einzige Bakterienart Bakteriochlorophyll g. Diese Bakterien wachsen photoheterotroph unter Verwendung organischer Verbindungen wie Pyruvat, Laktat, Acetat oder Butyrat. Zur Gruppe geh&#246;ren f&#252;nf Gattungen: Heliobacterium, Heliophilum, Heliorestis, Heliomonas und Heliobacillus. Sie treten als stabf&#246;rmige oder filament&#246;se Zellen auf, wobei Heliophilum bewegliche Zellb&#252;ndel bildet.
Eine weitere distinkte Gruppe anoxygener Phototrophe stellt Chloracidobacterium thermophilum dar, das zur Abteilung der Acidobacteria geh&#246;rt. Dieses thermophile Bakterium wurde in mikrobiellen Matten von Thermalquellen entdeckt. Es teilt bestimmte Eigenschaften mit gr&#252;nen Schwefelbakterien, wie die Produktion von Bakteriochlorophyll a und c in Chlorosomen und den Einsatz eines FeS-Typ-Photosystems. Im Gegensatz zu gr&#252;nen Schwefelbakterien ist C. thermophilum jedoch sauerstofftolerant und kann aerob wachsen. Es handelt sich um ein Photoheterotroph, das kurzkettige Fetts&#228;uren als Kohlenstoffquelle nutzt, jedoch nicht autotroph ist.
Diese Bakterien spielen eine wesentliche Rolle im globalen Schwefel- und Kohlenstoffkreislauf und besiedeln vielf&#228;ltige &#246;kologische Nischen mit geringem Sauerstoff- und hohem Schwefelgehalt.

Phototrophe Bakterien

Anoxygene phototrophe Bakterien sind eine vielf&#228;ltige Gruppe von Mikroorganismen, die Photosynthese ohne Sauerstoffproduktion betreiben. Sie umfassen ...

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sulfur-using bacteria that harvest light

Anoxygenic phototrophic bacteria are light-harvesting bacteria that do not release oxygen during photosynthesis. They include purple sulfur bacteria, purple nonsulfur bacteria, green sulfur bacteria, green nonsulfur bacteria, heliobacteria, and Chloracidobacterium thermophilum. These groups belong to the Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi, Chloroflexi, Firmicutes, and Acidobacteria lineages, and each group has its own habitat and way of using light.

Purple sulfur bacteria live in sulfur-rich, oxygen-free settings such as meromictic lakes, marine sediments, and salt marshes. They use hydrogen sulfide as an electron donor for photosynthesis. They first make elemental sulfur, store it inside the cell, and later oxidize it to sulfate. Common examples include Chromatium and Thiocapsa, and these bacteria contain bacteriochlorophyll a or b and use a Q-type photosystem.

Purple nonsulfur bacteria belong to the Alphaproteobacteria and Betaproteobacteria and are more flexible in how they live. They usually act as photoheterotrophs, which means they use light for energy and organic compounds for carbon. Some species can also grow photoautotrophically with hydrogen, low levels of hydrogen sulfide, or iron(II). Rhodobacter and Rhodospirillum are well-known genera, and these bacteria also contain bacteriochlorophyll a or b and Q-type photosystems.

Green sulfur bacteria are strict anaerobes, which means they grow only without oxygen, and they do not move. They use hydrogen sulfide as an electron donor, but unlike purple sulfur bacteria, they store elemental sulfur outside the cell. They fix carbon dioxide through the reverse citric acid cycle. Their light-harvesting structures are chlorosomes, and they contain bacteriochlorophyll c, d, or e. Chlorobaculum tepidum is a well-studied species that can live in sulfidic places with very little light.

Green nonsulfur bacteria, also called filamentous anoxygenic phototrophs, belong to Chloroflexi. They are mainly photoheterotrophs, but they can also do photoautotrophy with hydrogen or hydrogen sulfide. Their photosynthetic system combines features seen in purple and green sulfur bacteria. They have a Q-type photosystem and chlorosomes, and Chloroflexus aurantiacus is a common example from hot springs. Thermomicrobium is a related nonphototrophic genus with unusual membrane lipids.

Heliobacteria are gram-positive anoxygenic phototrophs in the phylum Firmicutes. They use an FeS-type photosystem and make bacteriochlorophyll g, which makes them different from the purple and green groups. They grow photoheterotrophically and use organic compounds such as pyruvate, lactate, acetate, or butyrate. The group includes Heliobacterium, Heliophilum, Heliorestis, Heliomonas, and Heliobacillus. These cells may be rod-shaped or filamentous, and Heliophilum can form motile bundles.

Chloracidobacterium thermophilum is another anoxygenic phototroph from the phylum Acidobacteria. It was discovered in microbial mats of thermal springs. It shares features with green sulfur bacteria because it makes bacteriochlorophyll a and c in chlorosomes and uses an FeS-type photosystem. However, it can tolerate oxygen and can grow aerobically. It is a photoheterotroph that uses short-chain fatty acids as a carbon source, but it does not have autotrophic growth. Together, these bacteria help drive sulfur and carbon cycling in low-oxygen, sulfur-rich environments.

Sulfur-Using Bacteria That Harvest Light

three-domain system of life

How rRNA Reshaped Life's Domains

Ribosomal RNA, or rRNA, changed how scientists classify life. Sequence analysis showed three major groups of cells: eukaryotes, bacteria, and archaea. In 1978, Carl R. Woese proposed domains as a taxonomic level above kingdoms to separate these groups. Woese also showed that archaea and bacteria are not the same, even though they can look similar. The three domains differ in rRNA, membrane lipid structure, transfer RNA, and sensitivity to antibiotics. These differences helped scientists build...

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modern molecular taxonomy

DNA Tools for Identifying Bacteria

DNA-based methods help scientists identify and compare bacteria with much greater precision. As sequencing becomes faster and less expensive, these tools are used in clinical, environmental, and evolutionary studies. They let researchers tell related strains apart and track how microbes spread. One important method is multilocus sequence typing, or MLST. It examines several housekeeping genes, which are essential chromosomal genes that support basic cell functions. About 450-base-pair...

applications of molecular taxonomy

Molecular Taxonomy in Bacterial Research

Molecular taxonomy in bacterial research uses DNA sequencing and DNA fingerprinting to classify bacteria more precisely. These molecular tools help scientists study bacterial diversity, evolutionary relationships, and ecological roles. They have changed how researchers identify and compare bacteria in both health and environmental studies. One major use of molecular taxonomy is resolving taxonomic ambiguities, or unclear classification cases. It can separate closely related bacteria that were...

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bacterial phylum verrucomicrobiota

Verrucomicrobiota Cell Structure and Traits

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Spirochete Shape, Motion, and Disease

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Cyanobacteria and Oxygenic Photosynthesis

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bacterial phylum bacteroidota

Gut and Environment Bacteria in Bacteroidota

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anoxygenic phototrophic bacteria

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hyperthermophilic bacteria

Heat-Loving Bacteria and Their Enzymes

Hyperthermophilic bacteria live in extreme heat and show unusual adaptations that help them survive. Several of these species come from the Domain Bacteria and are found in hot springs and hydrothermal vents. Their biology helps explain how life can function in very hot environments. Thermotoga species are rod-shaped, gram-negative, non-sporulating hyperthermophiles. They form a sheath-like outer layer called a toga. These bacteria ferment sugars or starch and produce lactate, acetate, carbon...

bacterial phylum tenericutes

Mycoplasmas and Wall-Less Bacteria

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diversity of archaea i

Archaea Extremes: Euryarchaeota

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diversity of archaea ii

New Archaea Phyla and Their Roles

Archaea are one of the three domains of life, and their diversity includes species that live in both extreme and moderate environments. For a long time, most known archaea were grouped into two major phyla: Euryarchaeota and Crenarchaeota. Recent molecular studies have added three more phyla to this picture: Thaumarchaeota, Nanoarchaeota, and Korarchaeota. Thaumarchaeota are mesophilic archaea, which means they live in moderate conditions. They are found in soils, lakes, and marine regions. A...

diversity of archaea iii

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diversity of archaea iv

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Microsporidia Spores and Host Infection

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fungal phylum ascomycota

Ascomycota: Sac Fungi and Their Spore Cycle

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fungal phylum basidiomycota

Basidiomycota: Mushrooms, Spores, and Ecological Roles

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Algae Structure, Habitats, and Reproduction

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red algae

Red Algae Pigments, Shapes, and Uses

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green algae

Green Algae: Forms, Habitats, and Roles

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overview of protists

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diversity of protists i

Excavata Protists and Their Adaptations

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diversity of protists ii

Alveolates: Ciliates, Dinoflagellates, Apicomplexans

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diversity of protists iii

Rhizaria: Pseudopods, Tests, and Skeletons

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diversity of protists iv

Amoebozoa: Movement and Life Cycles

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key terms and concepts

Explore how anoxygenic phototrophic bacteria use light without making oxygen, from purple and green sulfur bacteria to heliobacteria and thermal spring species.

Sulfur-Using Bacteria That Harvest Light | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Sulfur-Using Bacteria That Harvest Light

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