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1.
Myxovirus resistance (Mx) GTPases are induced by interferon and inhibit multiple viruses, including influenza and human immunodeficiency viruses. They have the characteristic domain architecture of dynamin-related proteins with an N-terminal GTPase (G) domain, a bundle signaling element, and a C-terminal stalk responsible for self-assembly and effector functions. Human MxA (also called MX1) is expressed in the cytoplasm and is partly associated with membranes of the smooth endoplasmic reticulum. It shows a protein concentration-dependent increase in GTPase activity, indicating regulation of GTP hydrolysis via G domain dimerization. Here, we characterized a panel of G domain mutants in MxA to clarify the role of GTP binding and the importance of the G domain interface for the catalytic and antiviral function of MxA. Residues in the catalytic center of MxA and the nucleotide itself were essential for G domain dimerization and catalytic activation. In pulldown experiments, MxA recognized Thogoto virus nucleocapsid proteins independently of nucleotide binding. However, both nucleotide binding and hydrolysis were required for the antiviral activity against Thogoto, influenza, and La Crosse viruses. We further demonstrate that GTP binding facilitates formation of stable MxA assemblies associated with endoplasmic reticulum membranes, whereas nucleotide hydrolysis promotes dynamic redistribution of MxA from cellular membranes to viral targets. Our study highlights the role of nucleotide binding and hydrolysis for the intracellular dynamics of MxA during its antiviral action.  相似文献   
2.
Formalin‐fixed paraffin‐embedded (FFPE) tissue is considered as an appropriate alternative to frozen/fresh tissue for proteomic analysis. Here we study formalin‐induced alternations on a proteome‐wide level. We compared LC‐MS/MS data of FFPE and frozen human kidney tissues by two methods. First, clustering analysis revealed that the biological variation is higher than the variation introduced by the two sample processing techniques and clusters formed in accordance with the biological tissue origin and not with the sample preservation method. Second, we combined open modification search and spectral counting to find modifications that are more abundant in FFPE samples compared to frozen samples. This analysis revealed lysine methylation (+14 Da) as the most frequent modification induced by FFPE preservation. We also detected a slight increase in methylene (+12 Da) and methylol (+30 Da) adducts as well as a putative modification of +58 Da, but they contribute less to the overall modification count. Subsequent SEQUEST analysis and X!Tandem searches of different datasets confirmed these trends. However, the modifications due to FFPE sample processing are a minor disturbance affecting 2–6% of all peptide‐spectrum matches and the peptides lists identified in FFPE and frozen tissues are still highly similar.  相似文献   
3.
We used measurements from airborne imaging spectroscopy and LiDAR to quantify the biophysical structure and composition of vegetation on a dryland substrate age gradient in Hawaii. Both vertical stature and species composition changed during primary succession, and reveal a progressive increase in vertical stature on younger substrates followed by a collapse on Pleistocene-aged flows. Tall-stature Metrosideros polymorpha woodlands dominated on the youngest substrates (hundreds of years), and were replaced by the tall-stature endemic tree species Myoporum sandwicense and Sophora chrysophylla on intermediate-aged flows (thousands of years). The oldest substrates (tens of thousands of years) were dominated by the short-stature native shrub Dodonaea viscosa and endemic grass Eragrostis atropioides. We excavated 18 macroscopic charcoal fragments from Pleistocene-aged substrates. Mean radiocarbon age was 2,002 years and ranged from < 200 to 7,730. Genus identities from four fragments indicate that Osteomeles spp. or M. polymorpha once occupied the Pleistocene-aged substrates, but neither of these species is found there today. These findings indicate the existence of fires before humans are known to have occupied the Hawaiian archipelago, and demonstrate that a collapse in vertical stature is prevalent on the oldest substrates. This work contributes to our understanding of prehistoric fires in shaping the trajectory of primary succession in Hawaiian drylands.  相似文献   
4.

Background

Accurate assessment of energy expenditure (EE) is important for the study of energy balance and metabolic disorders. Combined heart rate (HR) and acceleration (ACC) sensing may increase precision of physical activity EE (PAEE) which is the most variable component of total EE (TEE).

Objective

To evaluate estimates of EE using ACC and HR data with or without individual calibration against doubly-labelled water (DLW) estimates of EE.

Design

23 women and 23 men (22–55 yrs, 48–104 kg, 8–46%body fat) underwent 45-min resting EE (REE) measurement and completed a 20-min treadmill test, an 8-min step test, and a 3-min walk test for individual calibration. ACC and HR were monitored and TEE measured over 14 days using DLW. Diet-induced thermogenesis (DIT) was calculated from food-frequency questionnaire. PAEE (TEE ÷ REE ÷ DIT) and TEE were compared to estimates from ACC and HR using bias, root mean square error (RMSE), and correlation statistics.

Results

Mean(SD) measured PAEE and TEE were 66(25) kJ·day-1·kg-1, and 12(2.6) MJ·day-1, respectively. Estimated PAEE from ACC was 54(15) kJ·day-1·kg-1 (p<0.001), with RMSE 24 kJ·day-1·kg-1 and correlation r = 0.52. PAEE estimated from HR and ACC+HR with treadmill calibration were 67(42) and 69(25) kJ·day-1·kg-1 (bias non-significant), with RMSE 34 and 20 kJ·day-1·kg-1 and correlations r = 0.58 and r = 0.67, respectively. Similar results were obtained with step-calibrated and walk-calibrated models, whereas non-calibrated models were less precise (RMSE: 37 and 24 kJ·day-1·kg-1, r = 0.40 and r = 0.55). TEE models also had high validity, with biases <5%, and correlations r = 0.71 (ACC), r = 0.66–0.76 (HR), and r = 0.76–0.83 (ACC+HR).

Conclusions

Both accelerometry and heart rate may be used to estimate EE in adult European men and women, with improved precision if combined and if heart rate is individually calibrated.  相似文献   
5.
Breast cancer is the most prevalent cancer among women and mammography screening programs are seen as a key strategy to reduce breast cancer mortality. In Germany, women are invited to the population-based mammography screening program between ages 50 to 69. It is still discussed whether the benefits of mammography screening outweigh its harms. Therefore, the concept of informed choice comprising knowledge, attitude and intention has gained importance. The objective of this observational study was to assess the proportion of informed choices among women invited to the German mammography screening program for the first time. A representative sample of 17,349 women aged 50 years from a sub-region of North Rhine Westphalia was invited to participate in a postal survey. Turkish immigrant women were oversampled. The effects of education level and migration status on informed choice and its components were assessed. 5,847 (33.7%) women responded to the postal questionnaire of which 4,113 were used for analyses. 31.5% of the women had sufficient knowledge. The proportion of sufficient knowledge was lower among immigrants and among women with low education levels. The proportion of women making informed choices was low (27.1%), with similar associations with education level and migration status. Women of low (OR 2.75; 95% CI 2.18–3.46) and medium education level (OR 1.49; 95% CI 1.27–1.75) were more likely to make an uninformed choice than women of high education level. Turkish immigrant women had the greatest odds for making an uninformed choice (OR 5.30, 95% CI 1.92–14.66) compared to non-immigrant women. Other immigrant women only had slightly greater odds for making an uninformed choice than non-immigrant women. As immigrant populations and women with low education level have been shown to have poor knowledge, they need special attention in measures to increase knowledge and thus informed choices.  相似文献   
6.
The Escherichia coli secA gene, whose translation is responsive to the proficiency of protein export within the cell, is the second gene in a three-gene operon and is flanked by gene X and mutT. By using gene fusion and oligonucleotide-directed mutagenesis techniques, we have localized this translationally regulated site to a region at the end of gene X and the beginning of secA. This region has been shown to bind SecA protein in vitro. These studies open the way for a direct investigation of the mechanism of secA regulation and its coupling to the protein secretion capability of the cell.  相似文献   
7.
A transposable element has been isolated from the industrially important fungus Aspergillus niger (strain N402). The element was identified as an insertion sequence within the coding region of the nitrate reductase gene. It had inserted at a TA site and appeared to have duplicated the target site upon insertion. The isolated element was found to be 4798 by in length and contained 37-bp inverted, imperfect, terminal repeats (ITRs). The sequence of the central region of the element revealed an open reading frame (designated ORF1) which showed similarity, at the amino acid level, to the transposase of the Tc1/mariner class of DNA transposons. Another sequence within the central region of the element showed similarity to the 3 coding and downstream untranslated region of the amyA gene of A. niger. Sequence homology and structural features indicate that this element, which has been named Ant1 (A. niger transposon 1), is related to the Tc1/mariner group of DNA transposons. Ant1 is apparently present as a single copy in strain N402 of A. niger.  相似文献   
8.
9.
Cancer cells that escape induction therapy are a major cause of relapse. Understanding metabolic alterations associated with drug resistance opens up unexplored opportunities for the development of new therapeutic strategies. Here, we applied a broad spectrum of technologies including RNA sequencing, global untargeted metabolomics, and stable isotope labeling mass spectrometry to identify metabolic changes in P-glycoprotein overexpressing T-cell acute lymphoblastic leukemia (ALL) cells, which escaped a therapeutically relevant daunorubicin treatment. We show that compared with sensitive ALL cells, resistant leukemia cells possess a fundamentally rewired central metabolism characterized by reduced dependence on glutamine despite a lack of expression of glutamate-ammonia ligase (GLUL), a higher demand for glucose and an altered rate of fatty acid β-oxidation, accompanied by a decreased pantothenic acid uptake capacity. We experimentally validate our findings by selectively targeting components of this metabolic switch, using approved drugs and starvation approaches followed by cell viability analyses in both the ALL cells and in an acute myeloid leukemia (AML) sensitive/resistant cell line pair. We demonstrate how comparative metabolomics and RNA expression profiling of drug-sensitive and -resistant cells expose targetable metabolic changes and potential resistance markers. Our results show that drug resistance is associated with significant metabolic costs in cancer cells, which could be exploited using new therapeutic strategies.  相似文献   
10.
Psoriatic arthritis is a multigenic autoimmune disease that involves synovial tissue, entheseal sites and skin, and that may result in significant joint damage. Although there are no diagnostic tests for psoriatic arthritis, research has identified consistent features that help to distinguish the condition from other common rheumatic diseases. Comparison of HLA-B and HLA-C regions in psoriatic arthritis with those in psoriasis without joint involvement demonstrates significant differences, such that psoriatic arthritis cannot be viewed simply as a subset of genetically homogeneous psoriasis. T-cell receptor phenotypic studies have failed to identify antigen-driven clones, and an alternative hypothesis for CD8 stimulation involving innate immune signals is proposed. Finally, imaging studies have highlighted entheseal involvement in psoriatic arthritis, and it is possible that entheseal-derived antigens may trigger an immune response that is critically involved in disease pathogenesis.  相似文献   
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