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951.
Effect of acute activation of 5'-AMP-activated protein kinase on glycogen regulation in isolated rat skeletal muscle. 总被引:1,自引:0,他引:1
Licht Miyamoto Taro Toyoda Tatsuya Hayashi Shin Yonemitsu Masako Nakano Satsuki Tanaka Ken Ebihara Hiroaki Masuzaki Kiminori Hosoda Yoshihiro Ogawa Gen Inoue Tohru Fushiki Kazuwa Nakao 《Journal of applied physiology》2007,102(3):1007-1013
5'-AMP-activated protein kinase (AMPK) has been implicated in glycogen metabolism in skeletal muscle. However, the physiological relevance of increased AMPK activity during exercise has not been fully clarified. This study was performed to determine the direct effects of acute AMPK activation on muscle glycogen regulation. For this purpose, we used an isolated rat muscle preparation and pharmacologically activated AMPK with 5-aminoimidazole-4-carboxamide-1-beta-D-ribonucleoside (AICAR). Tetanic contraction in vitro markedly activated the alpha(1)- and alpha(2)-isoforms of AMPK, with a corresponding increase in the rate of 3-O-methylglucose uptake. Incubation with AICAR elicited similar enhancement of AMPK activity and 3-O-methylglucose uptake in rat epitrochlearis muscle. In contrast, whereas contraction stimulated glycogen synthase (GS), AICAR treatment decreased GS activity. Insulin-stimulated GS activity also decreased after AICAR treatment. Whereas contraction activated glycogen phosphorylase (GP), AICAR did not alter GP activity. The muscle glycogen content decreased in response to contraction but was unchanged by AICAR. Lactate release was markedly increased when muscles were stimulated with AICAR in buffer containing glucose, indicating that the glucose taken up into the muscle was catabolized via glycolysis. Our results suggest that AMPK does not mediate contraction-stimulated glycogen synthesis or glycogenolysis in skeletal muscle and also that acute AMPK activation leads to an increased glycolytic flux by antagonizing contraction-stimulated glycogen synthesis. 相似文献
952.
953.
Background
In single-cell human genome analysis using whole-genome amplified product, a strong amplification bias involving allele dropout and preferential amplification hampers the quality of results. Using an oligonucleotide single nucleotide polymorphism (SNP) array, we systematically examined the nature of this amplification bias, including frequency, degree, and preference for genomic location, and we assessed the effects of this amplification bias on subsequent genotype and chromosomal copy number analyses.Methodology/Principal Findings
We found a large variability in amplification bias among the amplified products obtained by multiple displacement amplification (MDA), and this bias had a severe effect on the genotype and chromosomal copy number analyses. We established optimal experimental conditions for pre-screening for high-quality amplified products, processing array data, and analyzing chromosomal structural alterations. Using this optimized protocol, we successfully detected previously unidentified chromosomal structural alterations in single cells from a lymphoblastoid cell line. These alterations were subsequently confirmed by karyotype analysis. In addition, we successfully obtained reproducible chromosomal copy number profiles of single cells from the cell line with a complex karyotype, indicating the applicability and potential of our optimized workflow.Conclusions/Significance
Our results suggest that the quality of amplification products should be critically assessed before using them for genomic analyses. The method of MDA-based whole-genome amplification followed by SNP array analysis described here will be useful for exploring chromosomal alterations in single cells. 相似文献954.
Masaru Nakano Hiroto Umehara Yoshihiro Hara Motohide Makino Mika Igarashi Mutsumi Nakada Toru Nakamura Yoichiro Hoshino Akira Kanno 《Molecular breeding : new strategies in plant improvement》2007,20(4):425-429
The class B genes, which belong to the MADS-box gene family, play important roles in regulating petal and stamen development
in flowering plants. These genes exist in two different types termed DEF- and GLO-like genes, and the B-function is provided by heterodimers of a DEF- and a GLO-like gene product. In the present study, dicot (tobacco and lettuce) and monocot (Tricyrtis hirta) plants were transformed with the GLO-like gene of Agapanthus praecox ssp. orientalis
ApGLO alone or in combination with the DEF-like gene of the same plant ApDEF. In two out of 10 transgenic tobacco plants containing ApGLO, sepals partially converted into petaloid organs. For lettuce, ray florets of four out of nine transgenic plants containing
ApGLO also developed additional petaloid organs. In two out of five transgenic T. hirta plants containing both ApGLO and ApDEF, organs developed in whorl 4 showed noticeable morphological alteration: they were much longer compared with carpels of non-transgenic
plants, and had purple spots overall on the surface as filaments of non-transgenic plants. No morphological alterations were
observed in vegetative organs between transgenic and non-transgenic plants for all the three species. The results obtained
in the present study indicate a possibility of molecular breeding for flower form alteration by genetic transformation with
the class B MADS-box gene(s) of heterologous plant species. 相似文献
955.
Yoshida H Itoh J Ohmori S Miyoshi K Horigome A Uchida E Kimizu M Matsumura Y Kusaba M Satoh H Nagato Y 《Plant biotechnology journal》2007,5(6):835-846
Cleistogamy is an efficient strategy for preventing gene flow from genetically modified (GM) crops. We identified a cleistogamous mutant of rice harbouring a missense mutation (the 45th residue isoleucine to threonine; I45T) in the class-B MADS-box gene SUPERWOMAN1 ( SPW1 ), which specifies the identities of lodicules (equivalent to petals) and stamens. In the mutant, spw1-cls , the stamens are normal, but the lodicules are transformed homeotically to lodicule–glume mosaic organs, thereby engendering cleistogamy. Since this mutation does not affect other agronomic traits, it can be used in crosses to produce transgenic lines that do not cause environmental perturbation. Molecular analysis revealed that the reduced heterodimerization ability of SPW1I45T with its counterpart class-B proteins OsMADS2 and OsMADS4 caused altered lodicule identity. spw1-cls is the first useful mutant for practical gene containment in GM rice. Cleistogamy is possible in many cereals by engineering class-B floral homeotic genes and thereby inducing lodicule identity changes. 相似文献
956.
Jinlong Yin Gunwoo Park Tae Hoon Kim Jun Hee Hong Youn-Jae Kim Xiong Jin Sangjo Kang Ji-Eun Jung Jeong-Yub Kim Hyeongsun Yun Jeong Eun Lee Minkyung Kim Junho Chung Hyunggee Kim Ichiro Nakano Ho-Shin Gwak Heon Yoo Byong Chul Yoo Jong Heon Kim Eun-Mi Hur Jeongwu Lee Seung-Hoon Lee Myung-Jin Park Jong Bae Park 《PLoS biology》2015,13(5)
957.
The protozoan parasite Entamoeba histolytica causes a wide spectrum of intestinal infections. In severe cases, the trophozoites can breach the mucosal barrier, invade the intestinal epithelium and travel via the portal circulation to the liver, where they cause hepatic abscesses, which can prove fatal if left untreated. The host Extra Cellular Matrix (ECM) plays a crucial role in amoebic invasion by triggering an array of cellular responses in the parasite, including induction of actin rich adhesion structures. Similar actin rich protrusive structures, known as ‘invadosomes’, promote chemotactic migration of the metastatic cancer cells and non-transformed cells by remodeling the ECM. Recent studies showed a central role for Rab GTPases, the master regulators of vesicular trafficking, in biogenesis of invadosomes. Here, we showed that fibronectin, a major host ECM component induced actin remodeling in the parasite in a Rab21 dependent manner. The focalized actin structures formed were reminiscent of the mammalian invadosomes. By using various approaches, such as immunofluorescence confocal microscopy and scanning electron microscopy, along with in vitro invasion assay and matrix degradation assay, we show that the fibronectin induced formation of amoebic actin dots depend on the nucleotide status of the GTPase. The ECM components, fibronectin and collagen type I, displayed differential control over the formation of actin dots, with fibronectin positively and collagen type I negatively modulating it. The cell surface adhesion molecule Gal/GalNAc complex was also found to impose additional regulation on this process, which might have implication in collagen type I mediated suppression of actin dots. 相似文献
958.
Balca R Mardin Alexandros P Drainas Sebastian M Waszak Joachim Weischenfeldt Mayumi Isokane Adrian M Stütz Benjamin Raeder Theocharis Efthymiopoulos Christopher Buccitelli Maia Segura‐Wang Paul Northcott Stefan M Pfister Peter Lichter Jan Ellenberg Jan O Korbel 《Molecular systems biology》2015,11(9)
A remarkable observation emerging from recent cancer genome analyses is the identification of chromothripsis as a one‐off genomic catastrophe, resulting in massive somatic DNA structural rearrangements (SRs). Largely due to lack of suitable model systems, the mechanistic basis of chromothripsis has remained elusive. We developed an integrative method termed “complex alterations after selection and transformation (CAST),” enabling efficient in vitro generation of complex DNA rearrangements including chromothripsis, using cell perturbations coupled with a strong selection barrier followed by massively parallel sequencing. We employed this methodology to characterize catastrophic SR formation processes, their temporal sequence, and their impact on gene expression and cell division. Our in vitro system uncovered a propensity of chromothripsis to occur in cells with damaged telomeres, and in particular in hyperploid cells. Analysis of primary medulloblastoma cancer genomes verified the link between hyperploidy and chromothripsis in vivo. CAST provides the foundation for mechanistic dissection of complex DNA rearrangement processes. 相似文献
959.
Yumiko KIRIHARA Mayumi TAKECHI Kaoru KUROSAKI Yuta KOBAYASHI Yoji SAITO Takashi TAKEUCHI 《Experimental Animals》2015,64(1):39-47
The anesthetic mixture of medetomidine (MED), midazolam (MID) and butorphanol (BUT)
produced anesthetic duration of around 40 minutes (min) in ICR mice. We reported that this
anesthetic mixture produced almost the same anesthetic effects in both male and female
BALB/c and C57BL/6J strains. Intraperitoneal (IP) administration of drugs has been widely
used in mice. However, various injectable routes of the anesthetic mixture may cause
different anesthetic effects. First, we examined effects of the anesthetic mixture by
subcutaneous (SC) and intravenous (IV) injection compared to IP injection. After injection
of the anesthetic mixture, administration of atipamezole (ATI) induced mice recovery from
anesthesia. Secondly, we examined how different dosage and optimum injection timing of ATI
affected mice recovery from anesthesia. We used an anesthetic score to measure anesthetic
duration and a pulse oximeter to monitor vital signs under anesthesia. Usually, drugs from
SC injection work more weakly than IP or IV injection. However, we found no significant
differences of anesthetic duration among the three different injection routes.
Antagonistic effects of ATI (0.3 mg/kg and 1.5 mg/kg) worked equally when administered at
30 min after injection of the anesthetic mixture. Antagonistic effects of ATI (1.5 mg/kg)
were stronger than ATI (0.3 mg/kg) at 10 min after injection of the anesthetic mixture.
The anesthetic mixture is a useful drug to induce nearly the same anesthetic effects by
different injection routes and has an antagonist of ATI which helps mice quickly recover
from anesthesia. These results may contribute to the welfare of laboratory animals. 相似文献
960.
Makoto Taniguchi Kazuyuki Kitatani Tadakazu Kondo Mayumi Hashimoto-Nishimura Satoshi Asano Akira Hayashi Susumu Mitsutake Yasuyuki Igarashi Hisanori Umehara Hiroyuki Takeya Junzo Kigawa Toshiro Okazaki 《The Journal of biological chemistry》2012,287(47):39898-39910
The role of “sphingolipid rheostat” by ceramide and sphingosine 1-phosphate (S1P) in the regulation of autophagy remains unclear. In human leukemia HL-60 cells, amino acid deprivation (AA(−)) caused autophagy with an increase in acid sphingomyleinase (SMase) activity and ceramide, which serves as an autophagy inducing lipid. Knockdown of acid SMase significantly suppressed the autophagy induction. S1P treatment counteracted autophagy induction by AA(−) or C2-ceramide. AA(−) treatment promoted mammalian target of rapamycin (mTOR) dephosphorylation/inactivation, inducing autophagy. S1P treatment suppressed mTOR inactivation and autophagy induction by AA(−). S1P exerts biological actions via cell surface receptors, and S1P3 among five S1P receptors was predominantly expressed in HL-60 cells. We evaluated the involvement of S1P3 in suppressing autophagy induction. S1P treatment of CHO cells had no effects on mTOR inactivation and autophagy induction by AA(−) or C2-ceramide. Whereas S1P treatment of S1P3 overexpressing CHO cells resulted in activation of the mTOR pathway, preventing cells from undergoing autophagy induced by AA(−) or C2-ceramide. These results indicate that S1P-S1P3 plays a role in counteracting ceramide signals that mediate mTOR-controlled autophagy. In addition, we evaluated the involvement of ceramide-activated protein phosphatases (CAPPs) in ceramide-dependent inactivation of the mTOR pathway. Inhibition of CAPP by okadaic acid in AA(−)- or C2-ceramide-treated cells suppressed dephosphorylation/inactivation of mTOR, autophagy induction, and autophagy-associated cell death, indicating a novel role of ceramide-CAPPs in autophagy induction. Moreover, S1P3 engagement by S1P counteracted cell death. Taken together, these results indicated that sphingolipid rheostat in ceramide-CAPPs and S1P-S1P3 signaling modulates autophagy and its associated cell death through regulation of the mTOR pathway. 相似文献