The Cytoplasmic Tail of FPC Antagonizes the Full-Length Protein in the Regulation of mTOR Pathway

FPC (fibrocystin or polyductin) is a single transmembrane receptor-like protein, responsible for the human autosomal recessive polycystic kidney disease (ARPKD). It was recently proposed that FPC undergoes a Notch-like cleavage and subsequently the cleaved carboxy(C)-terminal fragment translocates to the nucleus. To study the functions of the isolated C-tail, we expressed the intracellular domain of human FPC (hICD) in renal epithelial cells. By 3-dimensional (3D) tubulogenesis assay, we found that in contrast to tubule-like structures formed from control cells, hICD-expressing cells exclusively formed cyst-like structures. By western blotting, we showed that the Akt/mTOR pathway, indicated by increased phosphorylation of Akt at serine 473 and S6 kinase 1 at threonine 389, was constitutively activated in hICD-expressing cells, similar to that in FPC knockdown cells and ARPKD kidneys. Moreover, application of mTOR inhibitor rapamycin reduced the size of the cyst-like structures formed by hICD-expressing cells. Application of either LY294002 or wortmannin inhibited the activation of both S6K1 and Akt. Expression of full-length FPC inhibited the activation of S6 and S6 kinase whereas co-expression of hICD with full-length FPC antagonized the inhibitory effect of full-length FPC on mTOR. Taken together, we propose that FPC modulates the PI3K/Akt/mTOR pathway and the cleaved C-tail regulates the function of the full-length protein

CT and MRI imaging and interpretation of hepatic arterioportal shunts

Hepatic arterioportal shunts (HAPS) occur due to organic or functional fistulization of blood flow between arterial hepatic vasculature and venous portal systems. It is a type of hemodynamic abnormality of the liver being observed increasingly with the use of temporal imaging modalities. HAPS occur due to other underlying hepatic abnormalities including the presence of an underlying tumor or malignancy. When a HAPS is present, the appearance of these abnormalities on imaging studies suggests an underlying abnormality, must be considered atypical even if asymptomatic, and warrants careful evaluation. Over time, and as a function of degree of fistulae, symptoms and potential life-threatening complications may arise from the HAPS. These systemic complications may include the development of portal hypertension, splenomegaly, as well as accelerated metastasis in patients with malignant tumors. This manuscript reviews common underlying conditions associated with HAPS and their radiologic interpretation

Microbial community diversity and potential functionality in response to dam construction along the Three Gorge Reservoir, China

River and reservoir bacterial communities are the most basic part of river biomes and ecosystem structure, and play an important role in river biological processes. Yet, it remains unclear how highly regulated dam reservoirs affect both soil and sediment bacterial communities. A temporal distribution pattern of bacterial communities was investigated using Illumina MiSeq sequencing in a transition section of the Three Gorges Reservoir (TGR). In total, 106,682 features belong to the bacteria kingdom, encompassing 95 phyla, 228 classes, 514 orders, 871 families, 1959 genera, and 3,053 species. With water level regulation, Shannon diversity index, and observed species differed significantly, with no significant difference in Simpson evenness. Both in the high water level period (October) and the low water level period (June), Proteobacteria, Acidobacteri, and Chloroflexi were the most abundant phyla. Whereas, based on PCA plots and Circos plot, the microbial community structure has changed significantly. LEfSe method was used to identify the classified bacterial taxa with significant abundance differences between the low water level and high water level periods. KOs (KEGG Orthology) pathway enrichment analysis were conducted to investigate functional and related metabolic pathways in groups. To some extent, it can be inferred that water level regulation affects community growth by affecting the metabolism of the microbial community

Limited Regeneration Potential with Minimal Epicardial Progenitor Conversions in the Neonatal Mouse Heart after Injury

The regeneration capacity of neonatal mouse heart is controversial. In addition, whether epicardial cells provide a progenitor pool for de novo heart regeneration is incompletely defined. Following apical resection of the neonatal mouse heart, we observed limited regeneration potential. Fate-mapping of Tbx18MerCreMer mice revealed that newly formed coronary vessels and a limited number of cardiomyocytes were derived from the T-box transcription factor 18 (Tbx18) lineage. However, further lineage tracing with SM-MHCCreERT2 and Nfactc1Cre mice revealed that the new smooth muscle and endothelial cells are in fact derivatives of pre-existing coronary vessels. Our data show that neonatal mouse heart can regenerate but that its potential is limited. Moreover, although epicardial cells are multipotent during embryogenesis, their contribution to heart repair through "stem" or "progenitor" cell conversion is minimal after birth. These observations suggest that early embryonic heart development and postnatal heart regeneration are distinct biological processes. Multipotency of epicardial cells is significantly decreased after birth

Molecular cloning and preliminary function study of iron responsive element binding protein 1 gene from cypermethrin-resistant Culex pipiens pallens

<p>Abstract</p> <p>Background</p> <p>Insecticide resistance jeopardizes the control of mosquito populations and mosquito-borne disease control, which creates a major public health concern. Two-dimensional electrophoresis identified one protein segment with high sequence homology to part of <it>Aedes aegypti </it>iron-responsive element binding protein (IRE-BP).</p> <p>Method</p> <p>RT-PCR and RACE (rapid amplification of cDNA end) were used to clone a cDNA encoding full length IRE-BP 1. Real-time quantitative RT-PCR was used to evaluate the transcriptional level changes in the Cr-IRE strain <it>Aedes aegypti </it>compared to the susceptible strain of <it>Cx. pipiens pallens</it>. The expression profile of the gene was established in the mosquito life cycle. Methyl tritiated thymidine (³H-TdR) was used to observe the cypermethrin resistance changes in C6/36 cells containing the stably transfected IRE-BP 1 gene of <it>Cx. pipiens pallens</it>.</p> <p>Results</p> <p>The complete sequence of iron responsive element binding protein 1 (IRE-BP 1) has been cloned from the cypermethrin-resistant strain of <it>Culex pipiens pallens </it>(Cr-IRE strain). Quantitative RT-PCR analysis indicated that the IRE-BP 1 transcription level was 6.7 times higher in the Cr-IRE strain than in the susceptible strain of 4th instar larvae. The IRE-BP 1 expression was also found to be consistently higher throughout the life cycle of the Cr-IRE strain. A protein of predicted size 109.4 kDa has been detected by Western blotting in IRE-BP 1-transfected mosquito C6/36 cells. These IRE-BP 1-transfected cells also showed enhanced cypermethrin resistance compared to null-transfected or plasmid vector-transfected cells as determined by ³H-TdR incorporation.</p> <p>Conclusion</p> <p>IRE-BP 1 is expressed at higher levels in the Cr-IRE strain, and may confer some insecticide resistance in <it>Cx. pipiens pallens</it>.</p

Methylation of Hypothalamic Tsc1-mTOR Signaling in Regulation of Obesity and Obesity Resistance

The Tsc1-mTOR signaling pathway is often related to obesity, and epigenetic modification may lead to expression changes of obesity-related gene. Therefore, we aim to investigate the methylation of the Tsc1-mTOR signaling pathway in regulation of obesity susceptibility. Wistar rats were fed a normal diet or a high-fat diet to develop animal models. Protein and mRNA expression levels of Tsc1-mTOR signaling in the hypothalamus were determined by Western blot and quantitative real-time PCR. Methylation of Tsc1 gene promoter was detected by bisulfite genomic sequence. Both mRNA and protein expression levels of Tsc1 in DIO group hypothalamus were lower; mTOR and its downstream targets S6K1, 4EBP1, and S6 protein expression levels were higher than those of the DIO-R group and the chow group. The Tsc1 gene promoter methylation rate in the hypothalamus was 92.05±3.07% in the DIO group, 87.27±1.91% in the DIO-R group, and 88.18%±3.20% in the chow group, respectively, with significantly higher levels in the DIO group. Both the expression levels of Tsc1 gene promoter methylation and Tsc1-mTOR signaling pathway in the hypothalamus of DIO rats and DIO-R rats are different. These findings may shed light on the potential mechanism for the differentiation of obesity susceptibility

Study of the Judder Characteristics of Friction Material for an Automobile Clutch and Test Verification

Abstract The friction judder characteristics during clutch engagement have a significant influence on the NVH of a driveline. In this research, the judder characteristics of automobile clutch friction materials and experimental verification are studied. First, considering the stick-slip phenomenon in the clutch engagement process, a detailed 9-degrees-of-freedom (DOF) model including the body, each cylinder of the engine, clutch and friction lining, torsional damper, transmission and other driveline parts is established, and the calculation formula of friction torque in the clutch engagement process is determined. Second, the influence of the friction gradient characteristics on the amplification or attenuation of the automobile friction judder is analyzed, and the corresponding stability analysis and the numerical simulation of different friction gradient values are carried out with MATLAB/Simulink software. Finally, judder bench test equipment and a corresponding damping test program are developed, and the relationship between the friction coefficient gradient characteristics and the system damping is analyzed. After a large number of tests, the evaluation basis of the test is determined. The research results show that the friction lining with negative gradient characteristics of the friction coefficient will have a judder signal. When the friction gradient value is less than −0.005 s/m, the judder signal of the measured clutch cannot be completely attenuated, and the judder phenomenon occurs. When the friction gradient is greater than − 0.005 s/m, the judder signal can be significantly suppressed and the system connection tends to be stable

Loop Nucleotide Polymorphism in a Putative miRNA Precursor Associated with Seed Length in Rice (Oryza sativa L.)

licenses/by-nc-nd/3.0/). Reproduction is permitted for personal, noncommercial use, provided that the article is in whole, unmodified, and properly cited. Received: 2013.03.29; Accepted: 2013.06.05; Published: 2013.06.16 The terminal loop region of primary miRNA transcripts is an important determinant controlling miRNA function in human, animals and plants. However, the effects of polymorphisms in loop region of miRNA precusors on phenotypic variation have not been reported, especially on agronomic traits in rice. From rice japonica variety Koshihikari and indica Guichao2, we isolated a precursor of putative miRNA osa-MIR2923a. We detected a GG/AA polymorphism in the loop structure from japonica and indica rice varieties, which was corresponding to japonica/indica rice differentiation. By using high-resolution melting (HRM) analysis, we measured the polymorphisms in a RIL (recombinant inbred lines) population derived from japonica variety Koshihikari and indica Guichao2. We found that the GG/AA polymorphism in the osa-MIR2923a loop was correlated to grain length and length-width ratio. We further found the significant association between seed length and GG/AA polymorphism in a population consisting of 72 rice landraces. Three targets were predicted, whose expressions showed significant differences between the two varieties. Ou

Fast Nondominated Sorting Genetic Algorithm II with Lévy Distribution for Network Topology Optimization

Fast nondominated sorting genetic algorithm II (NSGA-II) is a classical method for multiobjective optimization problems and has exhibited outstanding performance in many practical engineering problems. However, the tournament selection strategy used for the reproduction in NSGA-II may generate a large amount of repetitive individuals, resulting in the decrease of population diversity. To alleviate this issue, Lévy distribution, which is famous for excellent search ability in the cuckoo search algorithm, is incorporated into NSGA-II. To verify the proposed algorithm, this paper employs three different test sets, including ZDT, DTLZ, and MaF test suits. Experimental results demonstrate that the proposed algorithm is more promising compared with the state-of-the-art algorithms. Parameter sensitivity analysis further confirms the robustness of the proposed algorithm. In addition, a two-objective network topology optimization model is then used to further verify the proposed algorithm. The practical comparison results demonstrate that the proposed algorithm is more effective in dealing with practical engineering optimization problems