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71.
Darius J.R. Lane Dong-Hun Bae Aritee R. Siafakas Yohan Suryo Rahmanto Lina Al-Akra Patric J. Jansson Robert A. Casero Des R. Richardson 《生物化学与生物物理学报:疾病的分子基础》2018,1864(9):2793-2813
Many biological processes result from the coupling of metabolic pathways. Considering this, proliferation depends on adequate iron and polyamines, and although iron-depletion impairs proliferation, the metabolic link between iron and polyamine metabolism has never been thoroughly investigated. This is important to decipher, as many disease states demonstrate co-dysregulation of iron and polyamine metabolism. Herein, for the first time, we demonstrate that cellular iron levels robustly regulate 13 polyamine pathway proteins. Seven of these were regulated in a conserved manner by iron-depletion across different cell-types, with four proteins being down-regulated (i.e., acireductone dioxygenase 1 [ADI1], methionine adenosyltransferase 2α [MAT2α], Antizyme and polyamine oxidase [PAOX]) and three proteins being up-regulated (i.e., S-adenosyl methionine decarboxylase [AMD1], Antizyme inhibitor 1 [AZIN1] and spermidine/spermine-N1-acetyltransferase 1 [SAT1]). Depletion of iron also markedly decreased polyamine pools (i.e., spermidine and/or spermine, but not putrescine). Accordingly, iron-depletion also decreased S-adenosylmethionine that is essential for spermidine/spermine biosynthesis. Iron-depletion additionally reduced 3H-spermidine uptake in direct agreement with the lowered levels of the polyamine importer, SLC22A16. Regarding mechanism, the “reprogramming” of polyamine metabolism by iron-depletion is consistent with the down-regulation of ADI1 and MAT2α, and the up-regulation of SAT1. Moreover, changes in ADI1 (biosynthetic) and SAT1 (catabolic) partially depended on the iron-regulated changes in c-Myc and/or p53. The ability of iron chelators to inhibit proliferation was rescuable by putrescine and spermidine, and under some conditions by spermine. Collectively, iron and polyamine metabolism are intimately coupled, which has significant ramifications for understanding the integrated role of iron and polyamine metabolism in proliferation. 相似文献
72.
Marcel Prothmann Florian von Knobelsdorff-Brenkenhoff Agnieszka T?pper Matthias A. Dieringer Etham Shahid Andreas Graessl Jan Rieger Darius Lysiak C. Thalhammer Till Huelnhagen Peter Kellman Thoralf Niendorf Jeanette Schulz-Menger 《PloS one》2016,11(2)
Background
Cardiovascular Magnetic Resonance (CMR) provides valuable information in patients with hypertrophic cardiomyopathy (HCM) based on myocardial tissue differentiation and the detection of small morphological details. CMR at 7.0T improves spatial resolution versus today’s clinical protocols. This capability is as yet untapped in HCM patients. We aimed to examine the feasibility of CMR at 7.0T in HCM patients and to demonstrate its capability for the visualization of subtle morphological details.Methods
We screened 131 patients with HCM. 13 patients (9 males, 56 ±31 years) and 13 healthy age- and gender-matched subjects (9 males, 55 ±31years) underwent CMR at 7.0T and 3.0T (Siemens, Erlangen, Germany). For the assessment of cardiac function and morphology, 2D CINE imaging was performed (voxel size at 7.0T: (1.4x1.4x2.5) mm3 and (1.4x1.4x4.0) mm3; at 3.0T: (1.8x1.8x6.0) mm3). Late gadolinium enhancement (LGE) was performed at 3.0T for detection of fibrosis.Results
All scans were successful and evaluable. At 3.0T, quantification of the left ventricle (LV) showed similar results in short axis view vs. the biplane approach (LVEDV, LVESV, LVMASS, LVEF) (p = 0.286; p = 0.534; p = 0.155; p = 0.131). The LV-parameters obtained at 7.0T where in accordance with the 3.0T data (pLVEDV = 0.110; pLVESV = 0.091; pLVMASS = 0.131; pLVEF = 0.182). LGE was detectable in 12/13 (92%) of the HCM patients. High spatial resolution CINE imaging at 7.0T revealed hyperintense regions, identifying myocardial crypts in 7/13 (54%) of the HCM patients. All crypts were located in the LGE-positive regions. The crypts were not detectable at 3.0T using a clinical protocol.Conclusions
CMR at 7.0T is feasible in patients with HCM. High spatial resolution gradient echo 2D CINE imaging at 7.0T allowed the detection of subtle morphological details in regions of extended hypertrophy and LGE. 相似文献73.
The structures of two new aliphatic acids, isomuronic and neuropogolic acid, from the lichen Neuropogon trachycarpus, were established by spectroscopic (MS, 1H and 13C NMR) and chemical evidence. Circular dichroism data allowed the configuration of isomuronic acid to be assigned as 2R. 相似文献
74.
75.
Type 2 Diabetes Inhibited Human Mesenchymal Stem Cells Angiogenic Response by Over‐Activity of the Autophagic Pathway 下载免费PDF全文
76.
Membrane association of the RNA-dependent RNA polymerase is essential for hepatitis C virus RNA replication 下载免费PDF全文
Moradpour D Brass V Bieck E Friebe P Gosert R Blum HE Bartenschlager R Penin F Lohmann V 《Journal of virology》2004,78(23):13278-13284
The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp), represented by nonstructural protein 5B (NS5B), belongs to a class of integral membrane proteins termed tail-anchored proteins. Its membrane association is mediated by the C-terminal 21 amino acid residues, which are dispensable for RdRp activity in vitro. For this study, we investigated the role of this domain, termed the insertion sequence, in HCV RNA replication in cells. Based on a structural model and the amino acid conservation among different HCV isolates, we designed a panel of insertion sequence mutants and analyzed their membrane association and RNA replication. Subgenomic replicons with a duplication of an essential cis-acting replication element overlapping the sequence that encodes the C-terminal domain of NS5B were used to unequivocally distinguish RNA versus protein effects of these mutations. Our results demonstrate that the membrane association of the RdRp is essential for HCV RNA replication. Interestingly, certain amino acid substitutions within the insertion sequence abolished RNA replication without affecting membrane association, indicating that the C-terminal domain of NS5B has functions beyond serving as a membrane anchor and that it may be involved in critical intramembrane protein-protein interactions. These results have implications for the functional architecture of the HCV replication complex and provide new insights into the expanding spectrum of tail-anchored proteins. 相似文献
77.
Sawomir Marek Dominik Tomaszewski Roma ytkowiak Anna Jasiska Marcin Zadworny Krystyna Boratyska Monika Dering Darius Danusevi
ius Jacek Oleksyn Tomasz P. Wyka 《Plant, cell & environment》2022,45(1):121-132
The commonly observed negative relationship between stomatal density (SD) and atmospheric CO2 has led to SD being proposed as an indicator of atmospheric CO2 concentration. The use of SD as a proxy for CO2, however, has been hampered by an insufficient understanding of the intraspecific variation of this trait. We hypothesized that SD in Pinus sylvestris, a widely distributed conifer, varies geographically and that this variation is determined by major climatic variables. By sampling needles from naturally growing trees along a latitudinal range of 32.25°, equivalent to 13.7°C gradient of mean annual temperature (MAT) across Europe, we found that SD decreased from the warmest southern sites to the coldest sites in the north at a rate of 4 stomata per mm2 for each 1°C, with MAT explaining 44% of the variation. Additionally, samples from a provenance trial exhibited a positive relationship between SD and the MAT of the original localities, suggesting that high SD is an adaptation to warm temperature. Our study revealed one of the strongest intraspecific relationships between SD and climate in any woody species, supporting the utility of SD as a temperature, rather than direct CO2, proxy. In addition, our results predict the response of SD to climate warming. 相似文献
78.
Saeedeh Ghaderi Yaghoub Fathipour Shahriar Asgari Gadi V. P. Reddy 《Journal of Applied Entomology》2019,143(5):493-507
Specifying the relationship between pests and their host plants in terms of damage is one of the basic concepts of integrated pest management (IPM) programmes. The crop loss and economic injury level (EIL) of Tuta absoluta (Lepidoptera: Gelechiidae) were determined on different tomato cultivars using gain threshold (field experiment) and regression (semi‐field experiment) methods. By assessing the crop loss in 2015 and 2016, four out of seven infested tomato cultivars had a significant yield loss in terms of weight of total fruits versus the control under the open‐field conditions. However, the total number of tomato cultivars had no significant difference to control treatment. The semi‐field experiment included six treatments (0, 2, 4, 6, 8 and 10 gravid females/plant) and examined two tomato cultivars. The tomato cages with between 6 and 10 gravid females/plant showed the highest number and weight of damaged fruits. Based on pesticide control costs, the market value of tomato and the control efficacy, we determined the EIL for T. absoluta. In the field experiment, the EIL value for T. absoluta on “Petomech,” “Cal JN3,” “Rio Grande” and “Early Urbana Y” cultivars was 4.15, 4.47, 4.70 and 5.04 larvae per plant, respectively. Based on regression equations, we calculated the EIL values for T. absoluta on “Cal JN3” and “Early Urbana Y” to be 4.75 and 5.44 larvae/plant, respectively. Crop loss assessment and EIL are necessary components of cost‐effective IPM programs and can be effective tools for making decisions about the application of pesticides against T. absoluta. 相似文献
79.
Zebra mussel filtration rates and regulating factors have been addressed earlier in a number of studies. Still, only a few
of them have taken into consideration the refiltration phenomenon, and therefore the direct extrapolation of experimental
results may only give the potential filtering capacity, and hence, over- or underestimate the actual amount of seston being
removed by zebra mussels in an ecosystem. The current experimental study aimed to gain insight into the refiltration effect
on the clearance rate of the zebra mussels at relatively high seston concentrations, and its potential role in controlling
the filtration efficiency of the zebra mussel population. The experiment was conducted in a laboratory flume following the
Latin squares design with one fixed (mussel density) and three random factors (initial total particulate matter (TPM) concentration,
flume “wall effect” and distance from the flume inflow area) considered. The results showed the significant effects of mussel
density and the TPM concentration on the effective clearance rate (ECR) of zebra mussels. The higher ECR values were obtained
at denser mussel clumps and lower TPM concentrations. The flume “wall effect” had no significant effect on the ECR, whereas
the distance from the flume inflow area appeared to have a significant impact. A positive relationship between ECR and the
zebra mussel density was most evident in the proximity of the TPM source. Based on the results, we assume that at high TPM
concentration, refiltration may assert itself by the elevated net clearance rate of mussels within dense clumps compared to
that of mussels at relatively low individual densities. This should be taken into consideration while modelling and assessing
the role of the zebra mussel in energy flow and redistribution of organic matter in an ecosystem. 相似文献
80.
Suryo Rahmanto Y Kalinowski DS Lane DJ Lok HC Richardson V Richardson DR 《The Journal of biological chemistry》2012,287(10):6960-6968
Nitrogen monoxide (NO) markedly affects intracellular iron metabolism, and recent studies have shown that molecules traditionally involved in drug resistance, namely GST and MRP1 (multidrug resistance-associated protein 1), are critical molecular players in this process. This is mediated by interaction of these proteins with dinitrosyl-dithiol-iron complexes (Watts, R. N., Hawkins, C., Ponka, P., and Richardson, D. R. (2006) Proc. Natl. Acad. Sci. U.S.A. 103, 7670-7675; Lok, H. C., Suryo Rahmanto, Y., Hawkins, C. L., Kalinowski, D. S., Morrow, C. S., Townsend, A. J., Ponka, P., and Richardson, D. R. (2012) J. Biol. Chem. 287, 607-618). These complexes are bioavailable, have a markedly longer half-life compared with free NO, and form in cells after an interaction between iron, NO, and glutathione. The generation of dinitrosyl-dithiol-iron complexes acts as a common currency for NO transport and storage by MRP1 and GST P1-1, respectively. Understanding the biological trafficking mechanisms involved in the metabolism of NO is vital for elucidating its many roles in cellular signaling and cytotoxicity and for development of new therapeutic targets. 相似文献