A Method of Utilizing Accounting Records for Nurseries Producing Field Grown Stock

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Selective inactivation of Stat3 in osteoclasts affect bone mass differently in female and male mice

poster abstractSignal Transducer and Activator of Transcription 3 (Stat3) is activated by the binding of various cytokines to their receptors, such as IL-6. Previous studies have revealed that conditional knockouts of Stat3 in osteoblasts and osteocytes cause a decrease in bone mineral density and strength. To study the role of Stat3 in osteoclasts, osteoclast- specific knockout mice were created using cre-lox recombination. Bone mineral density (BMD) and bone mineral content (BMC) were calculated for femurs and the fourth lumbar vertebra (L4) of 8 weeks old mice. Analysis revealed a decrease in BMD of femurs of osteoclast-selective Stat3 knockout (KOOc-Stat3) mice compared to their littermate control (p<0.05). There was also a decrease in BMC of the femurs of KOOc-Stat3 mice compared to the littermate controls (p<0.05). Analysis of μCT data from trabecular bone in the distal femur showed significant decreases in trabecular number and bone volume/tissue volume in both male and female KOOc-Stat3 mice. Trabecular separation was increased in male and female KOOc-Stat3 mice. Bone histomorphometry at the distal femur revealed a significant decrease in bone formation rate in males and females KOOc-Stat3 mice compared to the littermate controls. Osteoclast number identified by tartrate resistant acid phosphatase (TRAP) stain in female KOOc-Stat3 mice was significantly deficient from their control. These data suggest that inactivation of Stat3 in osteoclasts influences bone metabolism through both osteoblasts and osteoclasts. Knockout of Stat3 in either cell type leads to decreases in bone strength, making Stat3 a good drug target for treatment of diseases such as osteoporosis

How Will Declining Rates of Marriage Reshape Eligibility for Social Security?

For most older people in the United States, Social Security is the major source of income: nine out of ten people age 65 or older receive benefits, which represent an average of 41 percent of their income. Largely as a result of Social Security, poverty rates for the elderly are at an all-time low, just 10 percent. But pockets of poverty persist: older unmarried persons, blacks, and Hispanics experience poverty rates in excess of 20 percent, and over 40 percent of all older single black women live in poverty. People quality for Social Security based either on their work record or their marital status. Most older women receive noncontributory Social Security spouse of widow benefits on the basis of their marital history. For these women, marital status is more important than employment status in shaping old-age financial security. However, the trend to marry and stay married has declined over time in the United States, particularly among black women. This, we hypothesize, means that fewer women will qualify for spouse and widow benefits in coming decades. As a result, Social Security benefits will shrink among the very population that currently reports higher poverty rates, older single women, particularly black women. In this policy brief, we ask: Compared to earlier cohorts, what proportion of white, black, and Hispanic women born in the 1940s, 1950s, and 1960s will enter old age without a marriage that qualifies them for Social Security spouse and widow benefits? We find that the proportion who will reach age 62 without a qualifying marriage, and thus be ineligible for Social Security spouse and widow benefits, is increasing modestly for whites and Hispanics but dramatically for African Americans. Most of these women will be eligible for retired worker benefits under Social Security, but those benefits are not likely to be as large as the benefits they would have received as spouses and widows, had they been eligible. We then discuss a range of policy alternatives, including the possibility of a minimum benefit.Social Security, spousal benefits, widow benefits, poverty, elderly, social welfare, income security.

Structure and dynamics of the E. coli chemotaxis core signaling complex by cryo-electron tomography and molecular simulations

To enable the processing of chemical gradients, chemotactic bacteria possess large arrays of transmembrane chemoreceptors, the histidine kinase CheA, and the adaptor protein CheW, organized as coupled core-signaling units (CSU). Despite decades of study, important questions surrounding the molecular mechanisms of sensory signal transduction remain unresolved, owing especially to the lack of a high-resolution CSU structure. Here, we use cryo-electron tomography and sub-tomogram averaging to determine a structure of the Escherichia coli CSU at sub-nanometer resolution. Based on our experimental data, we use molecular simulations to construct an atomistic model of the CSU, enabling a detailed characterization of CheA conformational dynamics in its native structural context. We identify multiple, distinct conformations of the critical P4 domain as well as asymmetries in the localization of the P3 bundle, offering several novel insights into the CheA signaling mechanism