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A major difficulty in treating patients with pulmonary TB is that the organism can become progressively resistant to standard therapy. This resistance was long thought to be acquired through mutations in the infecting strain when the treatment regimen was inadequate or the patient did not comply with it. More recently, studies of the genetic make-up of Mycobacterium tuberculosis (M. tuberculosis) strains have shown that resistance can also result from re-infection with a new strain that is already drug-resistant, sometimes against multiple drugs. The authors of the new study, Qian Gao, PhD, and coworkers in Shanghai, China and elsewhere, used molecular genetics and drug susceptibility testing to investigate patients with TB who were treated in Shanghai hospitals during 1999-2004. They focused on 38 patients from whom samples were available before and during treatment. The researchers found that the strains of TB in the samples taken before treatment were genetically different f

Protein Lowry Bradford BCA Fluorescence α-Casein 0.91 BSA 1.00 1.00 1.00 1.00 Calf thymus 1.24 1.10 1.15 histones Chymotryp- 1.52 0.58 0.99 siongen A Cytochrome c 1.39 1.20 1.11 γ-Globulin 1.07 0.46 0.95 IgG (human) 1.03 IgG (mouse) 1.23 0.79 Lysozyme 1.54 1.00 0.97 Myoglobin 0.84 1.38 0.92 0.91 Ovalbumin 0.93 0.52 1.08 0.97 Ribonuclease A 1.28 0.68 Soybean trypsin 0.83 0.66 inhibitor Trypsin 1.34 0.34 Mean ± SD 1.18 ± 0.26 0.81 ± 0.34 1.04 ± 0.10 0.96 ± 0.11 a Estimated for highly purified proteins; relative to BSA. Data from: Peterson GL (1983) Meth Enzymol 91:95; Pierce (1996) Protein assay technical protocol; and Invitrogen/Molecular Probe Quant-iT Technical Bulletin (2004) 1.1.1 LOWRY Protein Quantification 1.1.1.1 Standard Procedure This protocol is slightlymodified,with respect to the original paper by Lowry et al., to work with smaller volumes. The Folin phenol method (Lowry protocol; Table 1.2) is useful in the widest variety of experimental a

The quantitative estimation of proteins is one of the basic requirements in biochemistry. In reviewing the biochemical literature for methods of fast and sensitive determination of the amount of protein, the large variety of proteins becomes evident, since theamount of protocols for quantitative protein seems to be innumerable. Proteins, from many points of view, are much more complex than, for example, nucleic acids. As a result, it has been difficult to give laboratory protocols that can be applied to proteins in general; however, in most cases the specialized protocolsmay be reduced to a few basic methods. But if a protein becomes pure or some of its unique properties are of special interest, another analytical method has to be used. Nevertheless, accurate quantitation of the amount of protein during the steps of protein preparation is the only valid way to evaluate the overall value of a procedure. The following protocols are based on distinct prope