Genome-Wide Evaluation of Histone Methylation Changes Associated with Leaf Senescence in Arabidopsis

Leaf senescence is the orderly dismantling of older tissue that allows recycling of nutrients to developing portions of the plant and is accompanied by major changes in gene expression. Histone modifications correlate to levels of gene expression, and this study utilizes ChIP-seq to classify activating H3K4me3 and silencing H3K27me3 marks on a genome-wide scale for soil-grown mature and naturally senescent Arabidopsis leaves. ChIPnorm was used to normalize data sets and identify genomic regions with significant differences in the two histone methylation patterns, and the differences were correlated to changes in gene expression. Genes that showed an increase in the H3K4me3 mark in older leaves were senescence up-regulated, while genes that showed a decrease in the H3K4me3 mark in the older leaves were senescence down-regulated. For the H3K27me3 modification, genes that lost the H3K27me3 mark in older tissue were senescence up-regulated. Only a small number of genes gained the H3K27me3 mark, and these were senescence down-regulated. Approximately 50% of senescence up-regulated genes lacked the H3K4me3 mark in both mature and senescent leaf tissue. Two of these genes, SAG12 and At1g73220, display strong senescence up-regulation without the activating H3K4me3 histone modification. This study provides an initial epigenetic framework for the developmental transition into senescence

Comparison of Extensive Protein Fractionation and Repetitive LC-MS/MS Analyses on Depth of Analysis for Complex Proteomes

In-depth, reproducible coverage of complex proteomes is challenging because the complexity of tryptic digests subjected to LC-MS/MS analysis frequently exceeds mass spectrometer analytical capacity, which results in undersampling of data. In this study, we used cancer cell lysates to systematically compare the commonly used GeLC-MS/MS (1-D protein + 1-D peptide separation) method using four repetitive injections (2-D/repetitive) with a 3-D method that included solution isoelectric focusing and involved an equal number of LC-MS/MS runs. The 3-D method detected substantially more unique peptides and proteins, including higher numbers of unique peptides from low-abundance proteins, demonstrating that additional fractionation at the protein level is more effective than repetitive analyses at overcoming LC-MS/MS undersampling. Importantly, more than 90 % of the 2-D/repetitive protein identifications were found in the 3-D method data in a direct protein level comparison, and the reproducibility between data sets increased to greater than 96 % when factors such as database redundancy and use of rigid scoring thresholds were considered. Hence, high reproducibility of complex proteomes, such as human cancer cell lysates, readily can be achieved when using multidimensional separation methods with good depth of analysis

Who will care for the women?

Over 20 million people today, including children, working-age disabled, and elderly persons, require some sort of assistance to live safely. Largely because women live longer than men, well into the ages when the probability of needing care increases, 70 percent of elderly people who need long-term care are women. Furthermore, most long-term care is provided by women, mainly as unpaid care in the home, or as low-paid care in institutions and community settings (Stone & Weiner 2001). The United States faces a severe long-term care crisis because of the nation\u27s inability to plan for the changing demographic balance. The crisis in long term care has two problems: a) that we are putting too many resources into institutional care relative to home- and community-based care and relying too heavily on unpaid care in the home to meet the real needs of the aging population, and b) that we do not, and increasingly will not, have enough people to provide for the volume of care that will be needed in the coming decades. This chapter begins with a description of the long-term care system in the United States – what long-term care is, who needs it, in what settings it is provided, and who pays for it. Using the author\u27s analysis of a national survey of caregivers conducted by the National Alliance for Caregiving and the AARP in 2003 along with other sources, this section shows that a substantial portion of the people who need long-term care rely on unpaid care from family and friends, mainly women. When people do receive paid care, almost half – mostly women -- receive it in institutional settings. The discussion demonstrates that women are far more likely to end up in institutions than men, even controlling for age and level of impairment. It then argues that, for a number of reasons, states and the federal government will have to respond to the preferences of consumers for home- and community-based care

WSES guidelines for management of Clostridium difficile infection in surgical patients

In the last two decades there have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease in many countries worldwide. The incidence of CDI has also increased in surgical patients. Optimization of management of C difficile, has therefore become increasingly urgent. An international multidisciplinary panel of experts prepared evidenced-based World Society of Emergency Surgery (WSES) guidelines for management of CDI in surgical patients