Definition

Noun 1. A taxonomic order of bacteria: Pseudomonadales is one of two orders traditionally recognized within the class of "true bacteria." This order is characterized by Gram-negative bacteria that can have spiral (spirilla), spherical (cocci), or rod-shaped (bacilli) forms. They are typically motile by means of polar flagella (flagella located at one or both ends of the cell). Some members of this order contain photosynthetic pigments.

Usage Examples

• The order Pseudomonadales includes many bacteria found in soil and water.
• Under the microscope, the motility of Pseudomonadales is often due to their polar flagella.
• Some families within Pseudomonadales are of significant medical and environmental importance.

Advanced Usage

• Taxonomic Context: In modern bacterial taxonomy, the classification is frequently revised. The name "Pseudomonadales" is a historical taxonomic rank, and many bacteria once grouped under it are now classified under different orders based on genetic analysis (e.g., within the class Gammaproteobacteria). It is now often considered an obsolete or invalid name in current systems.
  • Example: In contemporary phylogeny, the genus Pseudomonas is placed in the order Pseudomonadales in some historical texts, but is now more accurately placed in the order Pseudomonadales (if recognized) or within the larger class Gammaproteobacteria.

Variants and Related Words

• Pseudomonad (noun): A common, informal term for any bacterium belonging to the order Pseudomonadales or resembling its characteristics, especially bacteria of the genus .
  • Example: The infection was caused by a gram-negative pseudomonad.
• Pseudomonadaceae (noun): The name of a family within the order Pseudomonadales.

Synonyms

• Obsolete/Historical Synonyms: There are no direct common-language synonyms. In scientific literature, it may be referred to descriptively as "the pseudomonad order" or historically as one of the "true bacterial orders."

Related Phrases & Context

• Gram-negative bacteria: This is the primary staining characteristic of Pseudomonadales.
• Polar flagella: This is a key morphological feature for motility in this order.
• Photosynthetic pigments: A property of some members, like certain species.
• Genus Pseudomonas: The most famous and medically significant genus historically associated with this order, containing species like .

Noun

1. one of two usually recognized orders of true bacteria; Gram-negative spiral or spherical or rod-shaped bacteria usually motile by polar flagella; some contain photosynthetic pigments