Cover Picture: Proteomics 8/2009

In this issue of Proteomics you will find the following highlighted articles: Are you sick or are you just getting old: Does it matter? We all joke about the hazards of aging: various systems that break down, some you didn't even know you had. But then there's the alternative of not aging. Hmmm. Now what if aging were a disease? If so, it is worse than any cold I've had. Zürbig et al. have found that the proteome of the aging kidney has many markers in common with chronic kidney disease. The degree of match among small peptide markers ranged from 4% to 22% for IgA nephropathy to diabetic nephropathy, respectively. From these data they developed an age estimating scale that revealed some individuals had kidneys apparently “older” than their bodies. If these findings hold up, they could offer new approaches to diagnosis and therapy of chronic kidney diseases. Zürbig, P. et al., Proteomics 2009, 9, 2108‐2117. Sharing your niche with an unrelated species Anyone who's ever lived with a roommate knows the pain of dividing up the refrigerator space and the cleaning duties as well as the rent. Is it based on number of people, the size of bedrooms, or size of biceps? Many “free‐living” bacteria share their living space with other species in stable consortia to which each member contributes. Bobadilla Fazzini et al. use proteomic and other tools to examine the changes resulting from shifts in limiting carbon sources. Their system is a continuous culture of 9:1 Pseudomonas reinekei (MT1): Achromobacter xylosoxidans (MT3), cultured from a contaminated stream and able to grow on 4‐chlorosalicylate, an intermediate in the degradation of toxic furans and dioxins. MT1 OprF, the outer membrane protein and homolog of E. coli OmpA, is a “slow porin” that contributes to toxin resistance. After a shift in carbon sources, MT1 OprF was up‐regulated ～11‐fold in mixed culture vs. pure culture. Bobadilla Fazzini, R. A. et al., Proteomics 2009, 9, 2273‐2285. Heart to heart: Biomarkers for MACE Mace is a spice, not an herb. It is a badge of office and a weapon (albeit now of a defensive sort). It is also an acronym for a Major Adverse Cardiac Event, otherwise known as a big heart attack, something you want to know is coming and to prevent. So what to do? Biomarkers to the rescue. Currently the FDA has approved one prospective test: the CardioMPO? ELISA test for myeloperoxidase. The MPO marker is >60% accurate in predicting a MACE over 30 days and 6 months. Zhou et al. propose an alternative statistical method for evaluating a panel of mass spectrometry markers. An improved preprocessing procedure utilizes low‐level signal processing and spectrum cleanup routines followed by partial least squares logistic regression and support vector machine classifier to select the markers. The prediction is done by an improved genetic algorithm with local optimization. Using seven markers yields >75% accuracy. Zhou, X. et al., Proteomics 2009, 9, 2286‐2294.