Mycoplasma spp. belong to the class of mollicutes (derived from the Latin mollis=soft and cutis=skin, indicating that these organisms lack a cell wall). Mollicutes have evolved regressively from gram-positive bacteria (Clostridia). Within the class of mollicutes, the family Mycoplasmataceae includes the genera Mycoplas-ma and Ureaplasma, which represent the most important mollicutes in human medicine. The genome size of Mycoplasmataceae is small, ranging from 577 to 1380 kbp (Mycoplasma spp.) and from 760 to 1140 kbp (Ureaplasma spp.). The limited genomic information implies the extensive nutrient requirements of the organisms when cultured in vitro and the inability to survive outside their natural hosts. To date, complete genomes of Mycoplasma pneumoniae, Mycoplasma genitalium, Mycoplasma penetrans, and Ureaplasma urealyticum have been sequenced.
Although some Mycoplasma spp. are capable of invading human cells, close attachment to the host cells without invasion is typical. Diagnosis of infections with Mycoplasmataceae is challenging because of their fastidious growth in vitro. Standard single-step polymerase chain reaction (PCR) assays have been established for most human-pathogenic Mycoplasmataceae (Table 1). In addition, for the most clinically relevant species, advanced PCR-based methods such as real-time PCR or nucleic acid sequence-based amplification (NASBA) have been constructed.
When Mycoplasma spp. or Ureaplasma spp. cause infections in their main mucosal habitat (e.g., respiratory tract or urogenital tract), copy numbers above the sensitivity level of a standard single-step PCR are expectable. When a screening for colonization is performed, and notably when the pathogens are to be detected in other anatomical sites, methods providing superior sensitivity should be applied.
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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.