Structure Biochemistry and Genomics

Treponemes are spiral in shape, 6 to 15 pm in length and 0.1 to 0.2 pm in diameter. They contain two membranes: the inner cytoplasmic membrane and an outer membrane, which is unique in its lack of membrane proteins and lipopolysaccharides. An endoflagella is located in the periplasmic space between the two membranes.

T. pallidum cannot be continuously grown in culture; however, up to a 2000-fold expansion has been achieved when treponemes are inoculated into eukaryotic cell cultures in the presence of serum, 1.5-5% O2 and N2.[8,9] The optimal temperature for in vitro growth is 33-35°C; this limited temperature range may result from the presence of heat-labile enzymes such as 3-phosphoglyc-erate mutase and may be regulated by minerals such as manganese.[10]

The complete genome of T. pallidum has 1.138 million base pairs, encoding an estimated 1041 open reading frames, and is relatively small compared to the genome of Escherichia coli.[9,11] The genome lacks almost all the pathways for fatty acid, amino acid, and nucleotide biosynthesis, but the genome sequence also reveals 18 ABC transporters, which may be important for acquiring these nutrients from the host environment. The genome lacks respiratory components or obvious pathogenic factors or plasmids and contains five possible hemolysins and many flagellar genes.

Analysis of the genome indicates a strong codon usage bias toward G and in the leading strand. Proteins made from the lagging strand are high in arginine but low in lysine content.[12] In addition, the DNA metabolism-related proteins contain twice the amount of cysteine as cell envelope proteins.[13]

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

Get My Free Ebook

Post a comment