Identification and Characterization of Clinically Isolated Biofilm-forming Gram-positive Rods from Teeth Associated with Persistent Apical Periodontitis

The trimethoprim-resistance gene located on plasmid pSK1, originally identified in a multi-resistant Staphylococcus aureus from Australia, encodes the production of a dihydrofolate reductase (type S1), which confers a high degree of resistance to its host and is quite unlike any plasmid-encoded dihydrofolate reductase hitherto described. It has a low Mr (19,700) and has a higher specific activity than the constitutive Gram-negative plasmid dihydrofolate reductases. The type S1 enzyme is heat-stable and has a relatively low affinity for the substrate, dihydrofolate (Km 10.8 microM). It is moderately resistant to trimethoprim, and is competitively inhibited by this drug with an inhibitor-binding constant of 11.6 microM. This is the first identification and characterization of a plasmid-encoded trimethoprim-resistant dihydrofolate reductase derived from a Gram-positive species.

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Identification and characterization of the first β-1,3-d-xylosidase from a gram-positive bacterium, Streptomyces sp. SWU10

Enzyme and Microbial Technology ◽

10.1016/j.enzmictec.2017.11.002 ◽

2018 ◽

Vol 112 ◽

pp. 72-78 ◽

Cited By ~ 5

Author(s):

Pornpimol Phuengmaung ◽

Daisuke Fujiwara ◽

Wasana Sukhumsirichart ◽

Tatsuji Sakamoto

Keyword(s):

Positive Bacterium ◽

Gram Positive ◽

Streptomyces Sp ◽

Identification And Characterization

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Identification and characterization of a family of toxin–antitoxin systems related to the Enterococcus faecalis plasmid pAD1 par addiction module

Microbiology ◽

10.1099/mic.0.030932-0 ◽

2009 ◽

Vol 155 (9) ◽

pp. 2930-2940 ◽

Cited By ~ 48

Author(s):

Keith E. Weaver ◽

Shirisha G. Reddy ◽

Cassandra L. Brinkman ◽

Smita Patel ◽

Kenneth W. Bayles ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Biological Function ◽

Bacterial Species ◽

Saturation Mutagenesis ◽

Regulatory Rna ◽

Gram Positive ◽

Peptide Toxin ◽

Identification And Characterization ◽

Genetic Context

The par locus of the Enterococcus faecalis plasmid pAD1 is an RNA-regulated addiction module encoding the peptide toxin Fst. Homology searches revealed that Fst belongs to a family of at least nine related peptides encoded on the chromosomes and plasmids of six different Gram-positive bacterial species. Comparison of an alignment of these peptides with the results of a saturation mutagenesis analysis indicated regions of the peptides important for biological function. Examination of the genetic context of the fst genes revealed that all of these peptides are encoded within par-like loci with conserved features similar to pAD1 par. All four Ent. faecalis family members were demonstrated to produce the expected toxin-encoding and regulatory RNA products. The locus from the Ent. faecalis plasmid pAMS1 was demonstrated to function as an addiction module and Fst was shown to be toxic to Staphylococcus aureus, suggesting that a plasmid-encoded module in that species is performing the same function. Thus, the pAD1-encoded par locus appears to be the prototype of a family of related loci found in several Gram-positive species.

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