Surface plasmon resonance study of the actin-myosin sarcomeric complex and tubulin dimers

Biosensors based on the principle of surface plasmon resonance (SPR) detection were used to measure biomolecular interactions in sarcomeres and changes of the dielectric constant of tubulin samples with varying concentration. At SPR, photons of laser light efficiently excite surface plasmons propagating along a metal (gold) film. This resonance manifests itself as a sharp minimum in the reflection of the incident laser light and occurs at a characteristic angle. The dependence of the SPR angle on the dielectric permittivity of the sample medium adjacent to the gold film allows the monitoring of molecular interactions at the surface. We present results of measurements of cross-bridge attachment/detachment within intact mouse heart muscle sarcomeres and measurements on bovine tubulin molecules pertinent to cytoskeletal signal transduction models.Comment: Submitted to Journal of Modern Optics *Corresponding author: Andreas Mershin ([email protected]

Age-specific trends in health-related quality of life among US adults: Findings from National Health and Nutrition Examination Survey, 2001-2016

Purpose Health-related quality of life (HRQoL) is an important indicator of population health, yet no age-specific trend analyses in HRQoL have been conducted with a nationally representative sample since 2004. Therefore, to address this gap, an age-specific trend analysis of HRQoL was conducted using National Health and Nutrition Examination Surveys (NHANES) data. Methods NHANES 2001–2016 data (8 cycles) were examined to evaluate trends in HRQoL by age group (young adults: 21–39, middle-aged: 40–64, older adults: 65+). HRQoL was assessed by self-reported health (SRH) and number of physically unhealthy, mentally unhealthy, and inactive days to due to physical or mental health in the past 30 days. Multiple linear or logistic regression analyses explored trends in HRQoL by age group, adjusting for demographics over time. Results Analysis revealed increasing fair/poor SRH over time for the entire sample (β = 0.34, 95% CI 0.08, 0.60, p = 0.011). However, age-specific analysis identified a bi-annual increase in fair/poor SRH only among young adults (β = 0.49, 95% CI 0.22, 0.76, p \u3c 0.001) and a decrease among older adults (β = − 0.60, 95% CI − 1.14, − 0.06, p = 0.03). Closer inspection revealed increasing fair/poor SRH increased among young women (β = 0.52, 95% CI 0.11, 0.93, p = 0.013) and young men (β = 0.46, 95% CI 0.04, 0.88, p = 0.03) but decreased among older women (β = − 0.81, 95% CI − 1.59, − 0.03, p = 0.042) over time. Analyses also determined that there was a trend for a decreasing number of physically unhealthy days among young adults (p \u3c 0.001), although no trends were observed for the other HRQoL items. Conclusions Although there was a significant trend over time for increasing fair/poor SRH when considering the entire sample, this trend was not consistent between age groups or sexes. Given increasing fair/poor SRH among young adults, there is a need to understand and address factors relating to HRQoL among this age group

Resources and users in the tagging process: approaches and case studies

In this contribution we propose a comparison between two distinct approaches to the annotation of digital resources. The former, top-down, is rooted in the cathedral model and is based on an authoritative, centralized definition of the adopted mark-up language; the latter, bottom-up, refers to the bazaar model and is based on the contributions of a community of users. These two approaches are analyzed taking into account both their descriptive potential and the constraints they impose on the reasoning process of recommender systems, with special reference to user profiling. Three case studies are described, with reference to research projects that apply these approaches in the contexts of e-learning and knowledge management

Adaptive Reprogramming of the Breast Cancer Kinome

Our understanding of cancer has grown considerably with recent advances in high-throughput genome and transcriptome sequencing, but techniques to comprehensively analyze protein activity are still in development. Methods to quantitatively measure the activation of signaling pathways within tumors at baseline and following therapeutic intervention will prove critical to the design of proper treatment regimens. Focusing on breast cancer, we present such a method to understand kinase signaling using multiplexed kinase inhibitor beads coupled with mass spectrometry (MIB/MS)

The Relationships between Total Protein Intake, Protein Sources, Physical Activity, and Lean Mass in a Representative Sample of the US Adults

Background: Although dietary protein and physical activity play essential roles in developing and preserving lean mass, studies exploring these relationships are inconsistent, and large-scale studies on sources of protein and lean mass are lacking. Accordingly, the present study examined the relationship between total protein intake, protein sources, physical activity, and lean mass in a representative sample of US adults. Methods: This cross-sectional study analyzed data from 2011–2016 US National Health and Nutrition Examination Survey and corresponding Food Patterns Equivalents Database (n = 7547). Multiple linear regression models were performed to examine the sex-specific associations between total protein intake, protein sources (Dairy, Total Protein Foods, Seafood, and Plant Proteins), physical activity, and lean mass adjusting for demographics, weight status, and total daily energy intake. Results: Total protein intake was inversely related to lean mass in females only (Lean mass index: β= −0.84, 95%CI: −1.06–−0.62; Appendicular lean mass index: β= −0.35, 95%CI: −0.48–−0.22). However, protein sources and physical activity was positively associated with lean mass in males and/or females (p \u3c 0.05). Conclusion. Study results suggest that consuming more protein daily had a detrimental influence on lean mass in females whereas eating high-quality sources of proteins and being physically active are important for lean mass for men and women. However, the importance of specific protein sources appears to differ by sex and warrants further investigation

Temporal Association between Abdominal Weight Status and Healthy Aging: Findings from the 2011–2018 National Health and Aging Trends Study

Background/objectives: The longitudinal effect of abdominal weight status (AWS) defined by waist circumference (WC) on healthy aging has not yet been comprehensively examined. Therefore, the purpose of the present study was to examine the temporal association between WC-defined AWS and a comprehensive assessment for healthy aging. Subjects/methods: This study utilized data from 5211 respondents aged 65+ who participated in the National Health and Aging Trends Study from 2011 to 2018. Mixed effects regression models were used to examine the association between baseline AWS and the annual change rate in healthy aging score (HAS) via interaction terms (AWS*round) adjusting for confounding effects. Further multiple mixed models examined the relationship of AWS and HAS over an 8-year period. Results: There were no annual change rate differences in HAS by baseline AWS, regardless of sex. However, males with abdominal obesity were more likely to have a lower HAS than males with normal AWS (β = −0.20, 95% CI: −0.30, −0.10, p \u3c 0.001) but no difference in HAS was observed between males with overweight and normal AWS. A similar pattern was observed among females. Conclusions: Study results indicate that AWS was associated with HAS but it did not modify annual HAS change rate over time

Signal transduction by integrins: increased protein tyrosine phosphorylation caused by clustering of beta 1 integrins.

The integrin family of cell adhesion receptors mediates many of the interactions between cells and the extracellular matrix. Because the extracellular matrix has profound influences on cell behavior, it seems likely that integrins transduce biochemical signals across the cell membrane. The nature of these putative signals has, thus far, remained elusive. Antibody-mediated clustering of integrin receptors was used to mimic the integrin clustering process that occurs during formation of adhesive contacts. Human epidermal carcinoma (KB) cells were incubated with an anti-beta 1 integrin monoclonal antibody for 30 min on ice followed by incubation at 37 degrees C with anti-rat IgG. This treatment, which induced integrin clustering, stimulated the phosphorylation on tyrosine residues of a 115- to 130-kDa complex of proteins termed pp130. When integrins were clustered in the presence of the phosphatase inhibitor sodium orthovanadate, pp130 showed a substantial increase in phosphorylation compared to the case in which integrins were clustered in the absence of vanadate. Maximal pp130 phosphorylation was observed 10-20 min after initiation of integrin clustering in the absence of vanadate or after 5-10 min in its presence. These time courses roughly parallel the formation of integrin clusters on the cell surface as observed by fluorescence microscopy. pp130 phosphorylation depended on the amount of anti-integrin antibody present. Additionally, the tyrosine phosphorylation of pp130 showed specificity since it was stimulated by antibodies to the integrin alpha 3 and beta 1 subunits but not by antibodies to other integrin alpha subunits or to nonintegrin cell surface proteins. Immunoprecipitation experiments clearly demonstrated that pp130 is not itself a beta 1 integrin. It is postulated, therefore, that the integrin-stimulated tyrosine phosphorylation of pp130 may reflect part of an important signal transduction process between the extracellular matrix and the cell interior

Delayed Apoptotic Cell Clearance and Lupus-like Autoimmunity in Mice Lacking the c-mer Membrane Tyrosine Kinase

Mice lacking the membrane tyrosine kinase c-mer have been shown to have altered macro-phage cytokine production and defective phagocytosis of apoptotic cells despite normal phagocytosis of other particles. We show here that c-mer–deficient mice have impaired clearance of infused apoptotic cells and that they develop progressive lupus-like autoimmunity, with antibodies to chromatin, DNA, and IgG. The autoimmunity appears to be driven by endogenous antigens, with little polyclonal B cell activation. These mice should be an excellent model for studying the role of apoptotic debris as an immunogenic stimulus for systemic autoimmunity

Epidermal growth factor (EGF) stimulates EGF receptor synthesis

Epidermal growth factor (EGF) binds to the extracellular domain of a specific 170,000-dalton transmembrane glycoprotein; this results in rapid removal of both ligand and receptor from the cell surface. In WB cells, a rat hepatic epithelial cell line, ligand-directed receptor internalization leads to receptor degradation. We tested whether the EGF receptor was replenished at a constitutive or enhanced rate following EGF binding by immunoprecipitating biosynthetically labeled EGF receptor from cells cultured with [35S]methionine. EGF stimulated receptor synthesis within 2 h in a dose-dependent manner; this was particularly evident when examining the nascent form of the receptor. To determine the site of EGF action, total WB cell RNA was transferred to nitrocellulose paper after electrophoresis and was hybridized to cDNA probes from both the external and cytoplasmic coding regions of the human EGF receptor. EGF increased receptor mRNA by 3-5-fold. Therefore, at least in some cells, the surface action of EGF that leads to EGF receptor degradation is counterbalanced by a positive effect on receptor synthesis