Name: planctomycetes cell structure and life cycle
Uploaded: 2025-06-12T09:20:11.000Z
Duration: 1 min 26 s
Channel: JoVE

Planctomycetes are classified into two orders &#8212; Planctomycetales and Brocadiales.These Gram-negative bacteria exhibit unique features. They divide by budding. Some have stalks or appendages, while others form rosette-like cell arrangements. Certain species possess an S-layer in their cell envelope.All Planctomycetes show intracellular compartments resembling eukaryotic organelles.They produce specialized structures known as pirellulosomes, which are non-unit membrane-enclosed compartments containing the nucleoid, ribosomes, and other cytoplasmic components.In the genus Gemmata, the nucleoid is further enclosed by invaginations of the cell membrane, forming a structure surrounded by a true unit membrane.The genus Isosphaera is a filamentous, gliding bacterium found in hot springs.An additional noteworthy compartment, the anammoxosome, is found in members of the order Brocadiales, such as Brocadia anammoxidans.The anammoxosome facilitates the anaerobic oxidation of ammonia &#8212; a form of chemolithoautotrophy. The toxic hydrazine intermediate of this reaction is contained within its unique lipid membrane, protecting cytoplasmic components.

bacterial phylum planctomycetes 

Bacterial Phylum Planctomycetes 

Planctomycetes are a group of morphologically distinct bacteria predominantly classified into two orders: Planctomycetales and Brocadiales. These gram-negative bacteria exhibit unique features, including division by budding and the presence of stalks or appendages. Their cells are often found in rosette arrangements, and they are notable for possessing an S-layer in their cell envelope, which is relatively uncommon among bacteria. Additionally, Planctomycetes frequently exhibit intracellular compartments reminiscent of eukaryotic organelles.While prokaryotes and eukaryotes typically differ significantly in their cellular structures, Planctomycetes challenge this distinction by demonstrating cellular compartmentalization. Eukaryotic cells have a membrane-enclosed nucleus, whereas prokaryotic DNA is compacted into a nucleoid within the cytoplasm. However, Planctomycetes produce specialized structures known as pirellulosomes, which are non unit membrane-enclosed compartments containing the nucleoid, ribosomes, and other cytoplasmic components.The life cycle of Planctomyces involves budding. Motile swarmer cells attach to a surface, develop a stalk at the attachment site, and produce a new cell at the opposite pole through budding. This daughter cell then develops a flagellum, detaches from the mother cell, and initiates a new cycle. Physiologically, Planctomyces species are facultative aerobes capable of growing through either respiration or fermentation of sugars. They inhabit various aquatic environments, including freshwater and marine ecosystems. The genus Isosphaera, a relative of Planctomyces, is a filamentous, gliding bacterium found in hot springs. Isolation of Planctomyces and its relatives typically requires low-nutrient media.In certain genera, such as Gemmata, the nucleoid is further enclosed by invaginations of the cell membrane, forming a structure surrounded by a true unit membrane. Despite this structural complexity, the DNA remains in a covalently closed, circular, and supercoiled state typical of bacterial genomes.An additional noteworthy compartment, the anammoxosome, is found in members of the order Brocadiales, such as Brocadia anammoxidans. This structure facilitates the anaerobic oxidation of ammonia and is protected by a unique lipid membrane that prevents damage from toxic intermediates generated during this metabolic process.Planctomyces is one of the most thoroughly studied genera within the phylum. Similar to the stalked bacterium Caulobacter, Planctomyces features a stalk, but its structure is distinctly composed of protein without any cell wall or cytoplasm. The stalk primarily functions as an attachment mechanism and is more slender than the prosthecal stalk of Caulobacter.

Planctomycetes are a group of morphologically distinct bacteria predominantly classified into two orders: Planctomycetales and Brocadiales. These ...

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planctomycetes cell structure and life cycle

Planctomycetes are a group of gram-negative bacteria known for unusual cell structures and a distinctive life cycle. They are mainly placed in two orders, Planctomycetales and Brocadiales. Many cells show stalks or other appendages and often appear in rosette groups.

A key feature of these bacteria is their cell envelope. Planctomycetes have an S-layer, a surface layer that is relatively uncommon in bacteria. They also divide by budding, which is different from the simple cell split seen in many other bacteria.

Planctomycetes are also known for internal compartments that resemble parts of eukaryotic cells. Eukaryotes have a membrane-bound nucleus, while prokaryotes usually keep DNA in a nucleoid in the cytoplasm. In Planctomycetes, special compartments called pirellulosomes contain the nucleoid, ribosomes, and other cytoplasmic material.

The life cycle of Planctomyces begins with a motile swarmer cell attaching to a surface. A stalk forms at the attachment site, and a new cell then develops at the opposite pole by budding. The daughter cell grows a flagellum, leaves the mother cell, and starts the cycle again. Planctomyces species are facultative aerobes, so they can grow by respiration or by fermenting sugars, and they live in freshwater and marine environments. Low-nutrient media are usually needed to isolate Planctomyces and its relatives.

Some related bacteria show even more unusual structures. Isosphaera is a filamentous, gliding bacterium found in hot springs. In Gemmata, the nucleoid is further surrounded by membrane invaginations, so it has a true unit membrane around it. Even so, the DNA remains a covalently closed, circular, and supercoiled bacterial genome.

Members of Brocadiales include Brocadia anammoxidans, which has an anammoxosome. This compartment supports anaerobic oxidation of ammonia and is protected by a special lipid membrane that helps block toxic intermediates made during the process. Planctomyces is one of the best-studied genera in the phylum. It has a stalk like Caulobacter, but the Planctomyces stalk is made of protein only and does not contain cell wall or cytoplasm. Its main role is attachment, and it is thinner than the prosthecal stalk of Caulobacter.

Planctomycetes Cell Structure and Life Cycle

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Planctomycetes are a group of gram-negative bacteria known for unusual cell structures and a distinctive life cycle. They are mainly placed in two orders, Planctomycetales and Brocadiales. Many cells show stalks or other appendages and often appear in rosette groups. A key feature of these bacteria is their cell envelope. Planctomycetes have an S-layer, a surface layer that is relatively uncommon in bacteria. They also divide by budding, which is different from the simple cell split seen in...

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key terms and concepts

Explore Planctomycetes cell structure, budding division, stalks, and unique compartments like pirellulosomes and anammoxosomes in this high school biology video.

Planctomycetes Cell Structure and Life Cycle | 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

Planctomycetes Cell Structure and Life Cycle

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