Gram-positive bacteria are generally divided into the
Actinobacteria and the
Firmicutes.
The Actinobacteria or actinomycetes are a group of
Gram-positive bacteria with high G+C ratio. They include some of the most common soil bacteria. Other Actinobacteria inhabit plants and animals and including some pathogens, such as
Mycobacterium,
Corynebacterium,
Nocardia,
Rhodococcus and a few species of
Streptomyces. Actinobacteria produce secondary metabolites and are important to the pharmacological and biotechnology industries.
Streptomyces species, for example, produce important antibiotics. Some Actinobacteria form branching filaments and some
Actinomycetes species produce endospores.
The majority of Firmicutes have Gram-positive cell wall structure. However some, the Mollicutes or mycoplasmas, lack cell walls altogether and therefore do not respond to Gram staining. They do however lack the second (outer) membrane found in Gram-negative bacteria. Others members of the group, such as
Megasphaera,
Pectinatus,
Selenomonas, and
Zymophilus have a porous pseudo-outer-membrane that causes them to stain Gram-negative. The Firmicutes are generally restricted to a core group of related bacteria, called the low G+C group in contrast to the Actinobacteria. Firmicutes can be cocci or rod-shaped forms. Many produce endospores. They are found in various environments and some members of the group are important pathogens.
Recommended reading:Clostridia: Molecular Biology in the Post-genomic Era Corynebacteria: Genomics and Molecular BiologyMycobacterium: Genomics and Molecular BiologyBacillus: Cellular and Molecular BiologyStaphylococcus: Molecular GeneticsLactobacillus Molecular Biology: From Genomics to ProbioticsGenomics of GC-Rich Gram-Positive BacteriaLabels: bacillus, bacteriology, bacterium, clostridia, clostridium, corynebacterium, lactobacillus
Writing in the journal
Microbiology Today (Society for General Microbiology, UK), Paul Hoskisson of the University of Strathclyde, UK, reviews a new book on
Corynebacteria published by
Caister Academic Press:
"it is not surprising that this book has followed the Handbook of
Corynebacterium glutamicum (2005, Eggling & Bott, eds). Obviously there is some overlap in these volumes; however, this one is updated and brings in information relevant to other Corynebacteria ... There is a chapter on plasmids and promoters and their applications that researchers will find very useful in a practical sense ... researchers in the field with find this a useful and up to date addition to their library."
For full details please visit
Corynebacteria: Genomics and Molecular BiologyLabels: bacteriology, bacterium, book review, corynebacterium