Classifications and Species Characteristics

This section discusses Leuconostoc mesenteroides’ scientific classification and its basic background characteristics, as well as Leuconostoc mesenteroides’ classification as a lactic acid bacteria.

1.  Scientific Classification and Cell Characteristics

Scientific classification is a means by which scientists group organisms with common characteristics.  Leuconostoc meseneroides’ scientific classification is below (the classification becomes more specific going from “Kingdom” to “Species.”)

·         Leuconostoc meseneroides is a species, and can be divided further into subspecies.

·         Subspecies for example include Leuconostoc meseneroides subsp. meseneroides and Leuconostoc meseneroides subsp.cremoris.

·         Each subspecies has its own characteristics.

TABLE 1: Scientific Classification of Leuconostoc meseneroides

Source: Taxonomy Browser, http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=1245&lvl=3&keep=1&srchmode=1&unlock&lin=f

Classified in the Kingdom Bacteria, Leuconostoc mesenteroides share some characteristics with all bacteria: 

• They have no nucleus surrounded by membranes.
• They have no organelles surrounded by membranes.
• They have a DNA strand.
• They have a cell wall. 

In addition to the basic characteristics they share with others as members of the Bacteria Kingdom, Leuconostoc mesenteroides show the following characteristics. 

Shape

All bacteria do not have the same shape. Typical shapes are cocci, rods, and spirals. When Leuconostoc mesenteroides develop on solids, they are shaped as rods.  In liquids, Leuconostoc mesenteroides are shaped as cocci.  These cocci can be by themselves, with a few others, or joined together in long chains as shown below. 

FIGURE __: Leuconostoc mesenteroides Cocci

Source: JGI Genome Analysis and System Modeling Group of the Life Sciences Division of

 Oak Ridge National Laboratory. "Leuconostoc mesenteroides ATCC 8293." JGI Microbes . 7 Dec. 2008 <http://http://genome.jgi-psf.org/ finished_microbes/leume/leume.home.html>.

Photo: Fred Breidt, North Carolina State University

Cell Wall

Leuconostoc mesenteroides are Gram positive.  This means that they have an outer cell wall made of peptidoglycan.  To determine if a cell is gram positive or negative, the bacteria is stained with a crystal violet dye.  A purple color indicates peptidoglycan.  Peptidoglycan is a material made of a combination of sugars and amino acids.   Following are examples of Gram positive and negative bacteria.  Following also is a larger illustration of a typical Gram positive bacteria.

Figure ___: Gram Positive and Negative Bacteria

Gram Positive                                                             Gram Negative