T. whipplei is a short rod-shaped bacterium, approximately 0.3 mm in diameter and 1.5 mm long. Morphologically, the bacterium has a characteristically trilamellar ultrastructure including a plasmic membrane surrounded with a thin wall, itself surrounded with a structure like a plasmic membrane. This morphology is not typical of Gram-positive or Gram-negative bacteria. However, the bacterium appears Gram negative at the Gram staining, even if the phylogenic analysis classified it among the Gram-positive bacterium. T. whipplei is also well stained by PAS staining. The culture of T. whipplei has been an elusive goal for many generations of microbiologists. For the first time, in 1997, two strains of T. whipplei have been isolated from cardiac valves on a macrophage system in which microbicide functions have been inhibited. Unfortunately, no isolate has been subcultured. Two years later, the bacterium has not only been isolated but also established from a cardiac valve of a patient with WD endocarditis. More precisely, the bacterium has been propagated in human fibroblasts in minimum essential medium with 10% fetal calf serum and 2 mM gluta-mine. Since this work has been reproduced, four other strains have been isolated and established. Two strains were obtained in the same laboratory where the first strain of T. whipplei was established. One strain was isolated from a blood culture of a patient with WD endocarditis, and another strain was isolated from a duodenal biopsy from a patient with digestive WD. Two other strains obtained in another laboratory were from cerebro-spinal fluid samples. Finally, the availability of the sequenced genome of T. whipplei has allowed the successful design of a cell-free culture medium for T. whipplei. This medium provided missing amino acids (DMEM/F12 medium) and was supplemented with 10% fetal calf serum, 1% L-glutamine, and 1% nonessential amino acids. The culture flask was incubated vertically at 37°C in a 5% carbon dioxide atmosphere. The doubling time of T. whipplei was 28 hr and was unchanged from passage three up to now.
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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.