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Murdock TA, Varghese A, Xing D, Schoolmeester JK, Alexander C, Baergen RN, Dahoud W, Hopkins MR, Askin F, Vang R. Bizarre Chorionic-type Trophoblast in Second-trimester and Third-trimester Placentas: Clinicopathologic Characterization of a Placental Pseudoneoplastic Lesion. Am J Surg Pathol 2022; 46:258-267. [PMID: 34799484 DOI: 10.1097/pas.0000000000001838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bizarre (atypical/symplastic) cells have been described in various gynecologic normal tissues and benign neoplasms. This type of bizarre cytologic change is usually an incidental finding and is regarded as a benign process. We describe 17 cases of bizarre chorionic-type trophoblast in second-trimester and third-trimester placentas that created concern for an underlying/undersampled or incipient intraplacental trophoblastic neoplasm, predominantly found in intervillous trophoblastic islands (11/17), placental septae (6/17), chorionic plate (1/17), and/or the chorion layer of fetal membranes (2/17). The bizarre trophoblastic cells exhibited sheet-like or nested architecture, had a multifocal/patchy distribution, and/or were present as individual cells within hyaline stroma; they were characterized by large nuclei with smudgy chromatin and occasional intranuclear pseudoinclusions. The degree of atypia was classified as mild (0/17), moderate (3/17), or severe (14/17). Mitotic figures and necrosis were not identified. A dual immunohistochemical stain for trophoblast (hydroxyl-delta-5-steroid dehydrogenase) and a proliferation marker (Ki-67), performed in 15 cases, demonstrated 0% to very low proliferative activity within the bizarre trophoblast (0% to 2% [10/15], 3% to 8% [5/15]). Immunohistochemical stains for fumarate hydratase showed intact/retained expression in the bizarre cells in 7 of 7 cases. Clinical follow-up ranged from 1 to 45 months, and all patients were alive and well without subsequent evidence of a gestational trophoblastic or other neoplasms. We conclude that bizarre chorionic-type trophoblast in second-trimester or third-trimester placentas have the potential to mimic an intraplacental trophoblastic neoplasm but are likely a benign degenerative change. This study expands the spectrum of bizarre cells that occur in the gynecologic tract.
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Affiliation(s)
| | - Aaron Varghese
- Gynecology and Obstetrics, The Johns Hopkins Medical Institutions, Baltimore, MD
| | | | | | | | - Rebecca N Baergen
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY
| | | | | | - Frederic Askin
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC
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2
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Yamamoto K, Völkl A, Fahimi HD. Investigation of peroxisomal lipid beta-oxidation enzymes in guinea pig liver peroxisomes by immunoblotting and immunocytochemistry. J Histochem Cytochem 2017; 40:1909-18. [PMID: 1360481 DOI: 10.1177/40.12.1360481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We investigated the immunoreactivity of the peroxisomal lipid beta-oxidation enzymes acyl-CoA oxidase, trifunctional protein, and thiolase in guinea pig liver and compared it with that of homologous proteins in rat, using immunoblotting of highly purified peroxisomal fractions and monospecific antibodies to rat proteins. In addition, the immunocytochemical localization of beta-oxidation enzymes in guinea pig liver was compared with that of catalase. All antibodies showed crossreactivity between the two species, indicating that these peroxisomal proteins have been well conserved, although all exhibited some differences with respect to molecular size and, in the case of acyl-CoA oxidase, in frequency of the immunoreactive bands. In the latter case, a distinct second band in the 70 KD range was observed in guinea pig, in addition to the regular band due to subunit A present in rat liver. This novel band could be due either to trihydroxycoprostanoyl-CoA oxidase or to the non-inducible branched chain fatty acid oxidase described recently. All three beta-oxidation enzymes were immunolocalized by light and electron microscopy to the matrix of peroxisomes, in contrast to catalase, which is also found in the cytoplasm and the nucleus of hepatocytes in guinea pig liver.
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Affiliation(s)
- K Yamamoto
- Department of Anatomy and Cell Biology II, University of Heidelberg, Germany
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3
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Li CM, Miao Y, Lingeman RG, Hickey RJ, Malkas LH. Partial Purification of a Megadalton DNA Replication Complex by Free Flow Electrophoresis. PLoS One 2016; 11:e0169259. [PMID: 28036377 PMCID: PMC5201288 DOI: 10.1371/journal.pone.0169259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/12/2016] [Indexed: 02/03/2023] Open
Abstract
We describe a gentle and rapid method to purify the intact multiprotein DNA replication complex using free flow electrophoresis (FFE). In particular, we applied FFE to purify the human cell DNA synthesome, which is a multiprotein complex that is fully competent to carry-out all phases of the DNA replication process in vitro using a plasmid containing the simian virus 40 (SV40) origin of DNA replication and the viral large tumor antigen (T-antigen) protein. The isolated native DNA synthesome can be of use in studying the mechanism by which mammalian DNA replication is carried-out and how anti-cancer drugs disrupt the DNA replication or repair process. Partially purified extracts from HeLa cells were fractionated in a native, liquid based separation by FFE. Dot blot analysis showed co-elution of many proteins identified as part of the DNA synthesome, including proliferating cell nuclear antigen (PCNA), DNA topoisomerase I (topo I), DNA polymerase δ (Pol δ), DNA polymerase ɛ (Pol ɛ), replication protein A (RPA) and replication factor C (RFC). Previously identified DNA synthesome proteins co-eluted with T-antigen dependent and SV40 origin-specific DNA polymerase activity at the same FFE fractions. Native gels show a multiprotein PCNA containing complex migrating with an apparent relative mobility in the megadalton range. When PCNA containing bands were excised from the native gel, mass spectrometric sequencing analysis identified 23 known DNA synthesome associated proteins or protein subunits.
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Affiliation(s)
- Caroline M. Li
- Department of Molecular and Cellular Biology, Beckman Research Institute at City of Hope, Duarte, California, United States of America
- * E-mail:
| | - Yunan Miao
- Department of Molecular Medicine, Beckman Research Institute at City of Hope, Duarte, California, United States of America
| | - Robert G. Lingeman
- Department of Molecular and Cellular Biology, Beckman Research Institute at City of Hope, Duarte, California, United States of America
| | - Robert J. Hickey
- Department of Molecular Medicine, Beckman Research Institute at City of Hope, Duarte, California, United States of America
| | - Linda H. Malkas
- Department of Molecular and Cellular Biology, Beckman Research Institute at City of Hope, Duarte, California, United States of America
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Cagliero C, Zhou YN, Jin DJ. Spatial organization of transcription machinery and its segregation from the replisome in fast-growing bacterial cells. Nucleic Acids Res 2015; 42:13696-705. [PMID: 25416798 PMCID: PMC4267616 DOI: 10.1093/nar/gku1103] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In a fast-growing Escherichia coli cell, most RNA polymerase (RNAP) is allocated to rRNA synthesis forming transcription foci at clusters of rrn operons or bacterial nucleolus, and each of the several nascent nucleoids contains multiple pairs of replication forks. The composition of transcription foci has not been determined. In addition, how the transcription machinery is three-dimensionally organized to promote cell growth in concord with replication machinery in the nucleoid remains essentially unknown. Here, we determine the spatial and functional landscapes of transcription and replication machineries in fast-growing E. coli cells using super-resolution-structured illumination microscopy. Co-images of RNAP and DNA reveal spatial compartmentation and duplication of the transcription foci at the surface of the bacterial chromosome, encompassing multiple nascent nucleoids. Transcription foci cluster with NusA and NusB, which are the rrn anti-termination system and are associated with nascent rRNAs. However, transcription foci tend to separate from SeqA and SSB foci, which track DNA replication forks and/or the replisomes, demonstrating that transcription machinery and replisome are mostly located in different chromosomal territories to maintain harmony between the two major cellular functions in fast-growing cells. Our study suggests that bacterial chromosomes are spatially and functionally organized, analogous to eukaryotes.
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Affiliation(s)
| | | | - Ding Jun Jin
- To whom correspondence should be addressed. Tel: +1 301 846 7684; Fax: +1 301 846 1489;
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5
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Abstract
The current direct colorimetric assay for phytase activity in feeds has interference from high P background and other factors. Our objective was to develop a rapid and reliable spin column method to accurately determine phytase activity in feed ingredients or complete diets. After the feed sample was extracted by stirring in 0.2 M citrate buffer, pH 5.5, for 30 min at room temperature, the oily layer of the supernatant fraction was removed by passing through an acrodisc syringe filter (0.45-microm HT Tuffryn membrane, Gelman Laboratory, Ann Arbor, MI). The filtrate was then loaded onto a spin column (MW cutoff 30,000, Millipore, Bedford, MA) to remove free phosphate before the phytase activity assay. Compared with the direct assay, this new procedure improved both accuracy and reproducibility. When diets contained phytase at 0 to 1,500 U/kg (as fed), the CV for multiple assays of the same samples (n = 6) by the new method ranged from 1 to 6% compared with 28 to 39% by the direct method. A linear relationship was found between the added phytase activity in practical diets and the analyzed activity by the new method (r2 = 0.99; P < 0.01). In conclusion, the spin column method is an improved assay for phytase activity in animal feed, and may be used for quality control of phytase supplementation.
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Affiliation(s)
- T W Kim
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA
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To K, Yamaza H, Komatsu T, Hayashida T, Hayashi H, Toyama H, Chiba T, Higami Y, Shimokawa I. Down-regulation of AMP-activated protein kinase by calorie restriction in rat liver. Exp Gerontol 2007; 42:1063-71. [PMID: 17709221 DOI: 10.1016/j.exger.2007.07.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Revised: 04/21/2007] [Accepted: 07/05/2007] [Indexed: 11/18/2022]
Abstract
AMP-activated protein kinase (AMPK) may act as a key enzyme for metabolic adaptation to calorie restriction (CR) or reduced growth hormone (GH)-insulin-like growth factor (IGF)-1 signaling, an experimental intervention for lifespan extension in animals. We investigated the protein levels of AMPKalpha and a downstream enzyme, acetyl-CoA carboxylase (ACC), by immunoblotting of liver and quadriceps femoris muscle (QFM) extracts from 6-month-old wild-type (W) and GH-suppressed transgenic (Tg) Wistar rats fed ad libitum (AL) or 30% CR diets from 6weeks of age. A modified alternate-day feeding regimen for CR yielded a fed-fasted cycle in CR rats, and therefore the effects of overnight fasting in W-AL rats were also evaluated. CR decreased threonine-172-phosphorylated AMPKalpha (p-AMPKalpha; an activated form) levels in the liver, whereas the CR-fed-fasted cycle or overnight fasting did not significantly affect the p-AMPKalpha level. In the QFM, the p-AMPKalpha level was slightly elevated in the CR-fasted phase, but greatly increased in the AL-fasted phase. Suppression of GH did not affect the p-AMPKalpha level. The phosphorylated-ACC levels did not alter in parallel with the p-AMPKalpha level, particularly in the liver. The present results suggest that CR down-regulates the AMPK activity in the liver on a long-term basis.
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Affiliation(s)
- Kazuo To
- Department of Investigative Pathology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 12-4 Sakamoto 1-chome, Nagasaki City 852-8523, Japan
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7
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Mori K, Kitayama J, Aoki J, Kishi Y, Shida D, Yamashita H, Arai H, Nagawa H. Submucosal connective tissue-type mast cells contribute to the production of lysophosphatidic acid (LPA) in the gastrointestinal tract through the secretion of autotaxin (ATX)/lysophospholipase D (lysoPLD). Virchows Arch 2007; 451:47-56. [PMID: 17554559 DOI: 10.1007/s00428-007-0425-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 04/11/2007] [Accepted: 04/25/2007] [Indexed: 01/21/2023]
Abstract
Lysophosphatidic acid (LPA) is involved in a broad spectrum of biological activities, including wound healing and cancer metastasis. Autotaxin (ATX), originally isolated from a melanoma supernatant as a tumor cell motility-stimulating factor, has been shown to be molecularly identical to lysophospholipase D (lysoPLD), which is the main enzyme in the production of LPA. Although ATX/lysoPLD is known to be widely expressed in normal human tissues, the exact distribution of ATX-producing cells has not been fully investigated. In this study, we evaluated ATX/lysoPLD expression by immunohistochemical staining using a rat anti-ATX mAb in the human gastrointestinal tract and found that submucosal mast cells (MC) highly expressed this enzyme. This was confirmed by immunofluorescent double staining using mAbs to tryptase and chymase. Then, we isolated MC from human gastric tissue by an immunomagnetic method using CD117-microbeads and showed that a subpopulation of CD203c-positive MC showed positive staining for intracellular ATX/lysoPLD on flowcytometry. This was confirmed by Western blotting of the isolated cells. Moreover, a significant level of ATX/lysoPLD release could be detected in the culture supernatants of human MC by Western blot analysis. Our data suggest that submucosal MC play significant roles in various aspects of pathophysiology in the gastrointestinal tract by locally providing bioactive LPA through the production of ATX/lysoPLD.
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Affiliation(s)
- Ken Mori
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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Tokumura A, Kume T, Fukuzawa K, Tahara M, Tasaka K, Aoki J, Arai H, Yasuda K, Kanzaki H. Peritoneal fluids from patients with certain gynecologic tumor contain elevated levels of bioactive lysophospholipase D activity. Life Sci 2007; 80:1641-9. [PMID: 17367815 DOI: 10.1016/j.lfs.2006.12.041] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 11/13/2006] [Accepted: 12/12/2006] [Indexed: 11/28/2022]
Abstract
Levels of lysophosphatidic acid (LPA), an important phospholipid mediator, in serum and ascitic fluid from ovarian cancer patients were shown to be higher than those from healthy women and from patients with other type of cancer, respectively. Although LPA in human serum seems mainly to be generated by lysophospholipase D (lysoPLD), the source and pathway for LPA in the ascitic fluid remain still obscure. In this study, we examined whether lysoPLD activity producing bioactive LPA in human peritoneal fluid was significantly elevated under pathological statuses. Lysophospholipase D activity in human peritoneal fluids was measured by quantifying choline released from exogenous lysophosphatidylcholine on their incubation at 37 degrees C. We also compared the activity of lysoPLD in sera from patients with different gynecologic diseases. We found relatively high lysoPLD activity in peritoneal fluids from patients with ovarian cancer, dermoid cyst or mucinous cystadenoma, whereas there were no significant differences in the serum lysoPLD activity among clinical groups and healthy subjects. The lysoPLD in the peritoneal fluid was found to have similar substrate specificity and metal ion requirement to those of serum lysoPLD, that has been identified as autotaxin, a tumor cell-motility stimulating protein. Our results suggest that increased lysoPLD activity in peritoneal fluid from patients with certain gynecologic tumors might be relevant to its potential of tumor progression.
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Affiliation(s)
- Akira Tokumura
- Department of Health Chemistry, Institute of Health Biosciences, University of Tokushima Graduate School, 1-78-1 Shomachi, Tokushima, Japan.
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9
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Abstract
Mycobacterium spp. possess a complex cell envelope that consists of a plasma membrane, a peptidoglycan-arabinogalactan complex which in turn is esterified by mycolic acids that form with other non-bound lipids an asymmetric permeability barrier and an outer layer, also called a capsule in the case of pathogenic species. In order to investigate the functional roles of the cell envelope components, especially those of the major pathogens Mycobacterium tuberculosis and Mycobacterium leprae, it is necessary to fractionate the envelope by breaking the unusual wall that covers these bacteria. To this aim we first compared the efficiency of high pressure (cell disrupter/French press) with those of pathogen-compatible breakage methods such as sonication, bead beater and lysozyme treatment using the non-pathogenic Mycobacterium smegmatis. When the distribution of various specific markers of the cell envelope compartments, which include mycolic acids, arabinose, NADH oxidase activity, cell wall and cytosolic proteins, were determined sonication combined with lysozyme treatment was found to be the best option. The protocol of subcellular fractionation was then validated for pathogenic species by applying the method to Mycobacterium bovis BCG cells, an attenuated strain of the M. tuberculosis complex.
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Affiliation(s)
- Mandana Rezwan
- Institut für Medizinische Mikrobiologie, Gloriastrasse 32, Universität Zürich CH-8006 Zürich, Switzerland
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10
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Schubert-Unkmeir A, Sokolova O, Panzner U, Eigenthaler M, Frosch M. Gene expression pattern in human brain endothelial cells in response to Neisseria meningitidis. Infect Immun 2006; 75:899-914. [PMID: 17130252 PMCID: PMC1828482 DOI: 10.1128/iai.01508-06] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
To extend our knowledge of target proteins in endothelial cells infected with the meningitis-causing pathogen Neisseria meningitidis, we characterized the interaction between the bacterial and human brain microvascular endothelial cell (HBMEC) monolayers. By use of human cDNA microarrays, transcriptional analysis revealed distinct responses to 4 and 8 h of infection. We also addressed the question of whether the major virulence factor of meningococci, i.e., the capsule, influences the host cell response. Of the 1,493 (at 4 h postinfection) and 1,246 (at 8 h postinfection) genes with altered expression upon bacterial contact, about 49.4% and 45%, respectively, depended on capsule expression. In particular, we identified an increase of expression for genes encoding proteins involved in bacterial adhesion and invasion. High levels of apoptosis-related gene (bad, bak, asp, and immediate-early response gene 1) expression could also be detected in infected cells. Further analyses confirmed that HBMECs displayed several hallmarks of apoptosis in response to N. meningitidis infection, namely, phosphatidylserine translocation and activation of caspase 3 and AMP-activated protein kinase alpha. Moreover, several differentially regulated genes not previously known to respond to meningococcal infection were identified. Of these, genes encoding cell adhesion proteins (CD44, CD98, and CD99), genes involved in downstream signaling of integrins (integrin-linked kinase, mitogen-activated protein kinase kinase 1, and mitogen-activated protein kinase kinase kinase 10) as well as negative regulators of these pathways (dual-specificity phosphatases 1, 5, and 14 and G protein pathway suppressor 2), and genes involved in cytoskeleton reorganization (those encoding Arp2/3, p34-arc, actinin alpha 1, vasodilatator-stimulated protein, and Wiskott-Aldrich syndrome protein) were the most prominent. This global transcriptional analysis creates a new platform for further molecular and cellular analysis of the interaction between N. meningitidis and target cells.
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Suter M, Riek U, Tuerk R, Schlattner U, Wallimann T, Neumann D. Dissecting the role of 5'-AMP for allosteric stimulation, activation, and deactivation of AMP-activated protein kinase. J Biol Chem 2006; 281:32207-16. [PMID: 16943194 DOI: 10.1074/jbc.m606357200] [Citation(s) in RCA: 347] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a heterotrimeric protein kinase that is crucial for cellular energy homeostasis of eukaryotic cells and organisms. Here we report on the activation of AMPK alpha1beta1gamma1 and alpha2beta2gamma1 by their upstream kinases (Ca(2+)/calmodulin-dependent protein kinase kinase-beta and LKB1-MO25alpha-STRADalpha), the deactivation by protein phosphatase 2Calpha, and on the extent of stimulation of AMPK by its allosteric activator AMP, using purified recombinant enzyme preparations. An accurate high pressure liquid chromatography-based method for AMPK activity measurements was established, which allowed for direct quantitation of the unphosphorylated and phosphorylated artificial peptide substrate, as well as the adenine nucleotides. Our results show a 1000-fold activation of AMPK by the combined effects of upstream kinase and saturating concentrations of AMP. The two AMPK isoforms exhibit similar specific activities (6 mumol/min/mg) and do not differ significantly by their responsiveness to AMP. Due to the inherent instability of ATP and ADP, it proved impossible to assay AMPK activity in the absolute absence of AMP. However, the half-maximal stimulatory effect of AMP is reached below 2 microm. AMP does not appear to augment phosphorylation by upstream kinases in the purified in vitro system, but deactivation by dephosphorylation of AMPK alpha-subunits at Thr-172 by protein phosphatase 2Calpha is attenuated by AMP. Furthermore, it is shown that neither purified NAD(+) nor NADH alters the activity of AMPK in a concentration range of 0-300 microm, respectively. Finally, evidence is provided that ZMP, a compound formed in 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside-treated cells to activate AMPK in vivo, allosterically activates purified AMPK in vitro, but compared with AMP, maximal activity is not reached. These data shed new light on physiologically important aspects of AMPK regulation.
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Affiliation(s)
- Marianne Suter
- Institute of Cell Biology, Schafmattstrasse 18, ETH Zurich, 8093 Zurich, Switzerland
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12
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Abstract
In Escherichia coli, chemoreceptor clustering at a cell pole seems critical for signal amplification and adaptation. However, little is known about the mechanism of localization itself. Here we examined whether the aspartate chemoreceptor (Tar) is inserted directly into the polar membrane by using its fusion to green fluorescent protein (GFP). After induction of Tar–GFP, fluorescent spots first appeared in lateral membrane regions, and later cell poles became predominantly fluorescent. Unexpectedly, Tar–GFP showed a helical arrangement in lateral regions, which was more apparent when a Tar–GFP derivative with two cysteine residues in the periplasmic domain was cross-linked to form higher oligomers. Moreover, similar distribution was observed even when the cytoplasmic domain of the double cysteine Tar–GFP mutant was replaced by that of the kinase EnvZ, which does not localize to a pole. Observation of GFP–SecE and a translocation-defective MalE–GFP mutant, as well as indirect immunofluorescence microscopy on SecG, suggested that the general protein translocation machinery (Sec) itself is arranged into a helical array, with which Tar is transiently associated. The Sec coil appeared distinct from the MreB coil, an actin-like cytoskeleton. These findings will shed new light on the mechanisms underlying spatial organization of membrane proteins in E. coli.
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Affiliation(s)
- Daisuke Shiomi
- Division of Biological Science, Graduate School of Science, Nagoya UniversityChikusa-ku, Nagoya 464-8602, Japan
| | - Masayuki Yoshimoto
- Division of Biological Science, Graduate School of Science, Nagoya UniversityChikusa-ku, Nagoya 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya UniversityChikusa-ku, Nagoya 464-8602, Japan
| | - Ikuro Kawagishi
- Division of Biological Science, Graduate School of Science, Nagoya UniversityChikusa-ku, Nagoya 464-8602, Japan
- Institute for Advanced Research, Nagoya UniversityChikusa-ku, Nagoya 464-8602, Japan
- For correspondence. E-mail ; Tel. (+81) 52 789 2993; Fax (+81) 52 789 3001
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Kudo T, Asano J, Shimizu T, Nanashima N, Fan Y, Akita M, Ookawa K, Hayakari M, Yokoyama Y, Suto K, Tsuchida S. Different susceptibility to peroxisome proliferator-induced hepatocarcinogenesis in rats with polymorphic glutathione transferase genes. Cancer Sci 2006; 97:703-9. [PMID: 16800819 DOI: 10.1111/j.1349-7006.2006.00247.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Although peroxisomal bifunctional enzyme (enoyl-CoA hydratase/L-3-hydroxyacyl-CoA dehydrogenase; BE) is a positive marker for peroxisome proliferation, it is completely absent or expressed very weakly in rat hepatic preneoplastic and neoplastic lesions induced by peroxisome proliferators (PP). After administration of PP for 8-15 weeks, some rats exhibit BE-negative preneoplastic foci but other rats do not. In the present study, to investigate the involvement of glutathione S-transferase (GST) M1 gene polymorphism in interindividual differences in susceptibility to PP, we developed a method to determine the genotypes of rats. We then examined whether rats with one type encoding 198Asn-199Cys (NC-type) or another encoding 198Lys-199Ser (KS-type) exhibit differences in clofibrate (CF) susceptibility. After administration of 0.3% CF for 6 weeks or more, BE-negative foci were found immunohistochemically in KS/KS-type rats, but not in NC/NC-type rats. The number of BE-negative foci in KS/KS rats was 15.3 +/- 9.0 foci/cm2 of liver section after 6 weeks of CF administration, and the values did not alter thereafter. The mean areas of BE-negative foci in KS/KS rat livers increased during the period from 6 to 60 weeks. At weeks 30 and 60, almost all BE-negative foci exhibited a clear cell phenotype, a type of preneoplastic hepatic lesion. BE-negative foci were devoid of peroxisome proliferator-activated receptor alpha, whereas surrounding tissues were positive for the receptor. These results indicate that rats that are polymorphic for the GST M1 gene exhibit different susceptibilities to CF in vivo.
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Affiliation(s)
- Toshihiro Kudo
- Second Department of Biochemistry, Hirosaki University School of Medicine, 5 Zaifu- cho, Hirosaki 036-8562, Japan
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Bandyopadhyay GK, Yu JG, Ofrecio J, Olefsky JM. Increased malonyl-CoA levels in muscle from obese and type 2 diabetic subjects lead to decreased fatty acid oxidation and increased lipogenesis; thiazolidinedione treatment reverses these defects. Diabetes 2006; 55:2277-85. [PMID: 16873691 DOI: 10.2337/db06-0062] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Increased accumulation of fatty acids and their derivatives can impair insulin-stimulated glucose disposal by skeletal muscle. To characterize the nature of the defects in lipid metabolism and to evaluate the effects of thiazolidinedione treatment, we analyzed the levels of triacylglycerol, long-chain fatty acyl-coA, malonyl-CoA, fatty acid oxidation, AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), malonyl-CoA decarboxylase, and fatty acid transport proteins in muscle biopsies from nondiabetic lean, obese, and type 2 subjects before and after an euglycemic-hyperinsulinemic clamp as well as pre-and post-3-month rosiglitazone treatment. We observed that low AMPK and high ACC activities resulted in elevation of malonyl-CoA levels and lower fatty acid oxidation rates. These conditions, along with the basal higher expression levels of fatty acid transporters, led accumulation of long-chain fatty acyl-coA and triacylglycerol in insulin-resistant muscle. During the insulin infusion, muscle fatty acid oxidation was reduced to a greater extent in the lean compared with the insulin-resistant subjects. In contrast, isolated muscle mitochondria from the type 2 subjects exhibited a greater rate of fatty acid oxidation compared with the lean group. All of these abnormalities in the type 2 diabetic group were reversed by rosiglitazone treatment. In conclusion, these studies have shown that elevated malonyl-CoA levels and decreased fatty acid oxidation are key abnormalities in insulin-resistant muscle, and, in type 2 diabetic patients, thiazolidinedione treatment can reverse these abnormalities.
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Affiliation(s)
- Gautam K Bandyopadhyay
- Department of Medicine, Division of Endocrinology and Metabolism, University of California at San Diego, 9500 Gilman Dr., La Jolla, 92093, USA
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15
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Abstract
Sulfotransferases (Sults) are phase-II conjugation enzymes that catalyze the transfer of a sulfonate group from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to target endo and xenobiotics. PAPS is formed from inorganic sulfate by the action of the enzyme PAPS synthase (PAPSs). In the present study, the tissue distribution and developmental changes in the mRNA expression of 11 Sult isozymes and 2 PAPSs isoforms in mice were quantified. Sult1a1, 1b1, 1c1, 1c2, 1d1, 1e1, 2a1/2, 2b1, 3a1, 4a1, 5a1, PAPSs1, and PAPSs2 mRNA expression was quantified in 14 tissues from male and female mice using the branched DNA signal amplification assay. Sult2a1/2 and 3a1 expression were highest in liver; Sult1b1, 2b1, and PAPSs2 in small intestine; Sult1a1 in large intestine; Sult1c2 in stomach; Sult1d1 in kidney; Sult1e1 in placenta; and Sult4a1 in brain. Sult1c1, 5a1, and PAPSs1 were ubiquitously expressed in most tissues. These enzymes demonstrated three different ontogenic expression patterns in liver. Sult1a1, 1c2, 1d1, 2a1/2, and PAPSs2 hepatic expression gradually increased from birth until about 3 weeks of age and then declined somewhat thereafter, Sult1c1 expression was highest before birth and declined after that, and Sult3a1 mRNA expression was very low in fetal livers and remained low until 30 days of age, when expression in females dramatically increased, whereas it never increased in males. The organ-specific distribution of Sults as well as the different expression of the Sults in young animals may affect the pharmacokinetic behavior and organ-specific toxicity of xenobiotics.
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Affiliation(s)
- Yazen Alnouti
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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16
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Abstract
Exposure of Bacillus subtilis to a shear rate of 1,482/s leads to a rapid loss of cell viability after 10 h of growth. Biochemical and molecular evidences provided below strongly suggest that cell death under high shear results from an apoptosis-like process similar to that described in eukaryotes, with activation of a caspase-3-like protease (C(3)LP) followed by DNA fragmentation. Shear stress leads to an increase in specific intracellular reactive oxygen species (siROS), possibly through activation of NADH oxidase (NOX). The formation of siROS precedes the activation of C(3)LP and DNA fragmentation, thus establishing siROS as the molecular link between shear stress and apoptosis-like cell death. A model is proposed in which NOX is viewed as being strategically placed on the plasma membrane of B. subtilis that senses and converts a mechanical force arising from shear stress into a chemical signal leading to activation of C(3)LP, DNA fragmentation, and thus, apoptosis-like cell death.
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Affiliation(s)
- Susmita Sahoo
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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17
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Abstract
We have used a fusion of GFP to the response regulator OmpR to image the spatial distribution of OmpR in live cells of Escherichia coli. We observed foci of increased OmpR-GFP fluorescence that appear to be due to interactions with the histidine kinase EnvZ. We also observed colocalization of OmpR-GFP with clusters of plasmids carrying OmpR binding sites, which enabled us to develop a simple method for imaging the binding of OmpR to DNA in live cells. We used the peak fluorescence intensity within cells to quantify the extent of OmpR-GFP localization either due to interactions with EnvZ or due to binding DNA. With these assays we compared the effects of osmolarity and procaine, both of which are believed to modulate EnvZ activity. Our results suggest that, at least under our growth conditions, procaine activates EnvZ-OmpR signalling whereas osmolarity has, at best, a weak effect on the EnvZ-OmpR system.
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Affiliation(s)
- Eric Batchelor
- Department of Physics, University of Pennsylvania, Philadelphia, 19104, USA
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18
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Ferguson CG, Bigman CS, Richardson RD, van Meeteren LA, Moolenaar WH, Prestwich GD. Fluorogenic phospholipid substrate to detect lysophospholipase D/autotaxin activity. Org Lett 2006; 8:2023-6. [PMID: 16671772 PMCID: PMC2528860 DOI: 10.1021/ol060414i] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
[reaction: see text] Lysophospholipase D (lysoPLD), also known as autotaxin (ATX), is an important source of the potent mitogen lysophosphatidic acid (LPA). Two fluorogenic substrate analogues for lysoPLD were synthesized in nine steps from (S)-PMB-glycerol. The substrates (FS-2 and FS-3) show significant increases in fluorescence when treated with recombinant ATX and have potential applications in screening for this emerging drug target.
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Abstract
To evaluate whether metformin enhances leptin sensitivity, we measured leptin sensitivity after 4 weeks of metformin treatment (300 mg/kg daily) in both standard chow and high-fat-fed obese rats. Anorexic and fat-losing responses after intracerebroventricular leptin infusion for 7 days (15 microg daily per rat) in standard chow rats were enhanced by metformin treatment, and these responses to leptin were attenuated in high-fat-fed obese rats compared with age-matched standard chow rats. However, these responses to leptin were corrected by metformin treatment in high-fat-fed obese rats. Moreover, serum concentrations of leptin and insulin were decreased dramatically by leptin in metformin-treated standard chow and high-fat-fed obese rats. The hypothalamic phosphorylated AMP-activated protein kinase level was decreased by lower leptin dose in metformin-treated rats than in untreated rats. In an acute study, metformin treatment also increased the anorexic effect of leptin (5 microg), and this was accompanied by an increased level of phosphorylated signal transducer and activator of transcription 3 in the hypothalamus. These results suggest that metformin enhances leptin sensitivity and corrects leptin resistance in high-fat-fed obese rats and that a combination therapy including metformin and leptin would be helpful in the treatment of obesity.
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Affiliation(s)
- Yong-Woon Kim
- Department of Physiology, College of Medicine, Yeungnam University, #317-1, Daemyungdong, Namgu, Daegu 705-717, Republic of Korea.
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20
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Ostrowska H, Kruszewski K, Kasacka I. Immuno-proteasome subunit LMP7 is up-regulated in the ischemic kidney in an experimental model of renovascular hypertension. Int J Biochem Cell Biol 2006; 38:1778-85. [PMID: 16769238 DOI: 10.1016/j.biocel.2006.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 04/19/2006] [Accepted: 04/25/2006] [Indexed: 11/22/2022]
Abstract
Immuno-proteasome is thought to be responsible for the processing of intracellular antigens and is induced when cells are treated with the inflammatory cytokines promoting cellular immunity. We tested the possibility that immuno-proteasome can be up-regulated in renal cells exposed to a long-lasting ischemia and inflammation in an experimental model of two-kidney, one-clip renovascular hypertension in the rat. Western blotting showed that immuno-proteasome subunit, LMP7, was up-regulated in the clipped ischemic kidney that was atrophic, but not in the contralateral unclipped kidney that underwent compensatory hypertrophy. Immunohistochemical analysis revealed that LMP7 was highly expressed in cortical epithelial and endothelial cells of the ischemic kidney. Surprisingly, the second immuno-subunit, LMP2, was almost undetectable, indicating that renal ischemia may induce exclusively the LMP7 subunit. We also found that renal ischemia neither reduced the SDS-stimulated proteasomal activity nor affected a high level of the PA28 activator. Thus, the results provide evidence that LMP7 immuno-subunit is induced in renal cells exposed to a long-lasting renal ischemia and inflammation, and that there is a direct link between LMP induction and renal atrophy. This opens an opportunity to study a role for LMP-containing proteasomes in the kidneys and other organs undergoing reduction in mass in diseases accompanied by a long-lasting ischemia and inflammatory responses.
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Affiliation(s)
- Halina Ostrowska
- Department of Biology, Medical University of Bialystok, Kilinskiego 1, Bialystok 15-089, Poland.
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21
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Abstract
BACKGROUND Whether faulty DNA synthesis contributes to neuroblastoma (NB) pathogenesis has received little attention. We have shown that NB DNA replication is orchestrated by a multiprotein DNA replication complex (DNA synthesome) which mediates error-prone DNA synthesis. We sought to define proteomic alterations of the NB DNA synthesome, which lead to lowered replication fidelity. METHODS DNA synthesomes from NB and neural stem (NS) cell culture were purified. Proteomic differences of the DNA synthesome between NB and NS cells were determined using 2-dimensional polyacrylamide gel electrophoresis and immunodetection. RESULTS DNA synthesome proteins from NB and NS cells were compared. Only replication protein A (RPA) showed distinct changes. RPA from NS cells resolved as a single spot (isoelectric point [pI] 5.75), whereas RPA in NB showed a main spot (pI 5.75) along with 3 additional isoforms. RPA binds to single-stranded DNA and participates in protein-protein interactions. CONCLUSIONS NB DNA synthesome showed 3 distinct isoforms of RPA when compared with NS cells. These findings are significant in that it is possible to link changes in the fidelity of DNA replication with a specific protein alteration of the NB DNA synthetic apparatus. The novel RPA forms may be a new signature of NB malignancy.
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Affiliation(s)
- John A Sandoval
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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22
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McKay JS, Bigley A, Bell A, Jenkins R, Somers R, Brocklehurst S, White A, Goodwin L. A pilot evaluation of the use of tissue microarrays for quantitation of target distribution in drug discovery pathology. ACTA ACUST UNITED AC 2005; 57:181-93. [PMID: 16410186 DOI: 10.1016/j.etp.2005.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 09/06/2005] [Indexed: 11/30/2022]
Abstract
The use of tissue microarrays (TMAs) in the determination of novel target molecule distribution in organs is an expanding area of discovery pathology. This pilot study was carried out to assess the Chromavision automated cellular imaging system (ACIS) for quantitation of both mRNA and protein distribution in rat and dog TMAs. The targets chosen were a protein kinase, P-CIP2, for mRNA assessment and its downsteam target, peptidylglycine amidating monoxygenase (PAM), for immunohistochemistry (IHC). Oligonucleotide probes produced against P-CIP2, together with an antibody against PAM, were evaluated on rat and dog TMAs. A method for evaluation of target distribution using the ACIS was developed and involved a two-tier approach. Firstly, an initial scanning of the labelled slides identified which tissues expressed the target. Secondly, a more comprehensive analysis was made. This required operator interaction to select specific regions of interest within selected tissue cores and exclude any background labelling from the final assessment. This exacted the level of expression of P-CIP2 or PAM in different cellular populations in tissue cores. A comparative semi-quantitative analysis of the same arrays was concomitantly made by the pathologist in order to assess the relative benefits of a potentially time-consuming detailed morphological evaluation. This involved the histological identification by the pathologist of specific cell populations expressing P-CIP2 or PAM. In this study, we demonstrate the power of an image analysing system to provide quantitative data on target distribution by in situ hybridisation and IHC on normal TMAs. This methodology, together with detailed histological analysis by a pathologist, forms a guideline for future target distribution evaluation within discovery pathology.
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Affiliation(s)
- Jennifer S McKay
- Department of Pathology, Safety Assessment, AstraZeneca, Alderley Park, Cheshire SK10 4TG, UK.
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23
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Pérez-Jiménez JR, DeFraia C, Young LY. Arsenate respiratory reductase gene (arrA) for Desulfosporosinus sp. strain Y5. Biochem Biophys Res Commun 2005; 338:825-9. [PMID: 16242665 DOI: 10.1016/j.bbrc.2005.10.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 10/04/2005] [Indexed: 11/21/2022]
Abstract
Desulfosporosinus sp. strain Y5 is a spore-forming bacterium capable of dissimilatory arsenate reduction coupled to the oxidation of aromatic compounds. In arsenate respiration, the arsenate respiratory reductase (ARR) catalyzes the reduction of arsenate to arsenite. Our objective is to characterize the arrA gene, encoding the ARR, for Desulfosporosinus sp. strain Y5. Oligonucleotide primers were designed based on the few arrA gene sequences available at the time and validated against positive and negative controls. The resulting arrA-amplicon of approximately 2.0kb was cloned and sequenced. The arrA from Desulfosporosinus sp. Y5 is closely related to Desulfitobacterium hafniense (similarity of 77% and 81% at the nucleotide and amino acid levels, respectively). Phylogenetic topology based on the arrA gene was partially congruent with that of 16S rRNA-based analysis. This arrA sequence will support the development of specific tracking probes for Desulfosporosinus sp. Y5 and the molecular characterization and monitoring of dissimilatory arsenate reducing bacteria.
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Affiliation(s)
- José R Pérez-Jiménez
- Biotechnology Center for Agriculture and the Environment, Cook College, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
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24
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Abstract
The effects of 65 perfume formulations (perfume oils, perfumes, eau de parfum, eau de toilette) on mitochondrial membrane potential (ΔΨm) and mitochondrial respiration have been investigated using a mitochondria-based assay for ΔΨm, termed Psi-Screen. All the perfume formulations tested are highly active in the Psi-Screen assay, and the major site of inhibition in all cases is NADH-ubiquinone reductase (Complex I). This is confirmed in studies on the inhibition of NADH oxidase and NADH-ubiquinone reductase. Some formulations also inhibit succinate oxidation at either Complex II or Complex III. Evidence for the inhibition of mitochondrial ATPase is presented, as well as for the induction of reactive oxygen species production by perfume inhibition of Complex I. Thus, perfume formulations are multiple inhibitor mixtures which inhibit multiple bioenergetic functions at high dilutions (103 to 7 × 104). The implications of these findings are discussed with respect to cell toxicity via necrosis and/or apoptosis. Twenty candidate fragrance chemicals were investigated and all inhibited Complex I (5 at < 35μM). Mass screening strategies and high-throughput screening assays are discussed.
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Affiliation(s)
- David E Griffiths
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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25
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Meissner M, Reichert TE, Kunkel M, Gooding W, Whiteside TL, Ferrone S, Seliger B. Defects in the human leukocyte antigen class I antigen processing machinery in head and neck squamous cell carcinoma: association with clinical outcome. Clin Cancer Res 2005; 11:2552-60. [PMID: 15814633 DOI: 10.1158/1078-0432.ccr-04-2146] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Human leukocyte antigen (HLA) class I antigen defects, which are frequently present in head and neck squamous cell carcinoma (HNSCC) cells may provide the tumor with an escape mechanism from immune surveillance. Scanty information is available about mechanisms underlying HLA class I antigen defects in both lesions and cell lines from HNSCC. In this study, we investigate the role of antigen processing machinery (APM) component abnormalities in the generation of deficient HLA class I surface expression of HNSCC cells. EXPERIMENTAL DESIGN Using immunohistochemistry, Western blot, and RT-PCR analyses we correlated the expression of the IFN-gamma inducible proteasome subunits and of the peptide transporter TAP with that of HLA class I antigens in biopsies and cell lines from primary, recurrent, and metastatic HNSCC. Furthermore, APM component and HLA class I antigen expression in surgically removed lesions were correlated with the course of the disease in order to assess the clinical significance of deficient expression of these molecules. RESULTS A high frequency of LMP2, LMP7, and TAP1 down-regulation or loss was found in tumor lesions and cell lines obtained from HNSCC cancer patients. These defects could be corrected by incubating cells with IFN-gamma. Furthermore, LMP2, LMP7, TAP1, TAP2, and HLA class I antigen expression rates in primary HNSCC lesions were found to predict overall survival. Lastly, the level of LMP7 expression was significantly associated with disease recurrence at 2 years. CONCLUSIONS Our results suggest that the analysis of APM component expression in HNSCC lesions can provide useful prognostic information in patients with HNSCC.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 2
- ATP Binding Cassette Transporter, Subfamily B, Member 3
- ATP-Binding Cassette Transporters/analysis
- ATP-Binding Cassette Transporters/genetics
- Adult
- Aged
- Blotting, Western
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Cell Line
- Cell Line, Tumor
- Cysteine Endopeptidases/analysis
- Cysteine Endopeptidases/genetics
- Down-Regulation/drug effects
- Female
- Gene Expression Regulation, Neoplastic/drug effects
- HLA Antigens/analysis
- HLA Antigens/genetics
- Head and Neck Neoplasms/genetics
- Head and Neck Neoplasms/metabolism
- Head and Neck Neoplasms/pathology
- Histocompatibility Antigens Class I/analysis
- Histocompatibility Antigens Class I/genetics
- Humans
- Immunohistochemistry
- Interferon-gamma/pharmacology
- Male
- Middle Aged
- Multienzyme Complexes/analysis
- Multienzyme Complexes/genetics
- Proteasome Endopeptidase Complex
- Reverse Transcriptase Polymerase Chain Reaction
- Survival Analysis
- Tumor Cells, Cultured
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Affiliation(s)
- Markus Meissner
- Department of Internal Medicine, Johannes Gutenberg-University, Mainz, Germany
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26
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Abstract
RATIONALE Sepsis significantly alters skeletal muscle mitochondrial function, but the mechanisms responsible for this abnormality are unknown. OBJECTIVES We postulated that endotoxin elicits specific changes in electron transport chain proteins that produce derangements in mitochondrial function. To examine this issue, we compared the effects of endotoxin-induced sepsis on mitochondrial ATP (adenosine triphosphate) formation and electron transport chain protein composition. METHODS AND MEASUREMENTS Diaphragm mitochondrial oxygen consumption and mitochondrial nicotinamide adenine dinucleotide, reduced form, oxidase assays were measured in control rats (n=13) and rats given endotoxin (8 mg/kg/d) for 12 (n=14), 24 (n=14), 36 (n=14), and 48 h (n=13). Electron transport chain subunits from Complexes I, III, IV, and V were isolated using Blue Native polyacrylamide gel electrophoresis techniques. MAIN RESULTS Endotoxin administration: 1) elicited large reductions in mitochondrial oxygen consumption (e.g., 201+/-3.9 SE natoms O/min/mg for controls and 101+/-4.5 SE natoms O/minutes/mg after 48 h endotoxin, p<0.001), in nicotinamide adenine dinucleotide, reduced form, oxidase activity (p<0.002), and in uncoupled respiration (p<0.001) and 2) induced selective reductions in two subunits of Complex I, three subunits of Complex III, one subunit of Complex IV, and one subunit of Complex V. The time course of depletion of protein subunits mirrored alterations in oxygen consumption. CONCLUSIONS Our data indicate that endotoxin selectively depletes critical components of the electron transport chain that diminishes electron flow, reduces proton pumping and decreases ATP formation.
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Affiliation(s)
- Leigh A Callahan
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Medical College of Georgia, Augusta GA 30912-3135, USA.
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27
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Bao JL, Le J, Tian YP, Yang YP, Wang HH. [Protein profiling of human dendritic cells infected with mycobacterium tuberculosis]. Wei Sheng Wu Xue Bao 2005; 45:415-9. [PMID: 15989238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The response of dendritic cells (DCs) plays an essential role in the initiation of immune responses following Mycobacterium tuberculosis (MTB) challenge. Two-dimensional electrophoresis (2-DE) was employed to compare the global protein patterns between human DCs infected and that uninfected with MTB H37Rv ATCC 27294 strains, and 45 protein spots were found to express differentially. Four protein spots which remarkably changed in DCs infected with MTB H37Rv ATCC 27294 strains were measured by matrix assisted laser desorption/ionization tandem time-of-flight (TOF/TOF) mass spectrometry. The data obtained from peptide mass fingerprinting were used in protein database search. Four protein spots in gel were identified as Human Arsenite-stimulated ATPase (hASNA-I), Annexin IV, gamma-actin and Heat shock protein27 (HSP27). These data provide insight into the changed global protein patterns of the DCs after infection and may prove useful for further study in the interaction between MTB and host.
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Affiliation(s)
- Jia-ling Bao
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433, China.
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28
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Jørgensen SB, Wojtaszewski JFP, Viollet B, Andreelli F, Birk JB, Hellsten Y, Schjerling P, Vaulont S, Neufer PD, Richter EA, Pilegaard H. Effects of alpha-AMPK knockout on exercise-induced gene activation in mouse skeletal muscle. FASEB J 2005; 19:1146-8. [PMID: 15878932 DOI: 10.1096/fj.04-3144fje] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We tested the hypothesis that 5'AMP-activated protein kinase (AMPK) plays an important role in regulating the acute, exercise-induced activation of metabolic genes in skeletal muscle, which were dissected from whole-body alpha2- and alpha1-AMPK knockout (KO) and wild-type (WT) mice at rest, after treadmill running (90 min), and in recovery. Running increased alpha1-AMPK kinase activity, phosphorylation (P) of AMPK, and acetyl-CoA carboxylase (ACC)beta in alpha2-WT and alpha2-KO muscles and increased alpha2-AMPK kinase activity in alpha2-WT. In alpha2-KO muscles, AMPK-P and ACCbeta-P were markedly lower compared with alpha2-WT. However, in alpha1-WT and alpha1-KO muscles, AMPK-P and ACCbeta-P levels were identical at rest and increased similarly during exercise in the two genotypes. The alpha2-KO decreased peroxisome-proliferator-activated receptor gamma coactivator (PGC)-1alpha, uncoupling protein-3 (UCP3), and hexokinase II (HKII) transcription at rest but did not affect exercise-induced transcription. Exercise increased the mRNA content of PGC-1alpha, Forkhead box class O (FOXO)1, HKII, and pyruvate dehydrogenase kinase 4 (PDK4) similarly in alpha2-WT and alpha2-KO mice, whereas glucose transporter GLUT 4, carnitine palmitoyltransferase 1 (CPTI), lipoprotein lipase, and UCP3 mRNA were unchanged by exercise in both genotypes. CPTI mRNA was lower in alpha2-KO muscles than in alpha2-WT muscles at all time-points. In alpha1-WT and alpha1-KO muscles, running increased the mRNA content of PGC-1alpha and FOXO1 similarly. The alpha2-KO was associated with lower muscle adenosine 5'-triphosphate content, and the inosine monophosphate content increased substantially at the end of exercise only in alpha2-KO muscles. In addition, subcutaneous injection of 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR) increased the mRNA content of PGC-1alpha, HKII, FOXO1, PDK4, and UCP3, and alpha2-KO abolished the AICAR-induced increases in PGC-1alpha and HKII mRNA. In conclusion, KO of the alpha2- but not the alpha1-AMPK isoform markedly diminished AMPK activation during running. Nevertheless, exercise-induced activation of the investigated genes in mouse skeletal muscle was not impaired in alpha1- or alpha2-AMPK KO muscles. Although it cannot be ruled out that activation of the remaining alpha-isoform is sufficient to increase gene activation during exercise, the present data do not support an essential role of AMPK in regulating exercise-induced gene activation in skeletal muscle.
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Affiliation(s)
- Sebastian B Jørgensen
- Copenhagen Muscle Research Centre, Department of Human Physiology, Institute of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark.
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29
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Anderson SN, Cool BL, Kifle L, Chiou W, Egan DA, Barrett LW, Richardson PL, Frevert EU, Warrior U, Kofron JL, Burns DJ. Microarrayed compound screening (microARCS) to identify activators and inhibitors of AMP-activated protein kinase. ACTA ACUST UNITED AC 2004; 9:112-21. [PMID: 15006134 DOI: 10.1177/1087057103260592] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A novel and innovative high-throughput screening assay was developed to identify both activators and inhibitors of AMP-activated protein kinase (AMPK) using microarrayed compound screening (microARCS) technology. Test compounds were arrayed at a density of 8640 on a polystyrene sheet, and the enzyme and peptide substrate were introduced into the assay by incorporating them into an agarose gel followed by placement of the gels onto the compound sheet. Adenosine triphosphate (ATP) was delivered via a membrane, and the phosphorylated biotinylated substrate was captured onto a streptavidin affinity membrane (SAM trade mark ). For detection, the SAM trade mark was removed, washed, and imaged on a phosphor screen overnight. A library of more than 700,000 compounds was screened using this format to identify novel activators and inhibitors of AMPK.
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Affiliation(s)
- Steven N Anderson
- Department of Biological Screening, Abbott Laboratories, Global Pharmaceutical Research and Development, Abbott Park, IL 60064, USA.
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30
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Abstract
RNA polymerase II carboxy terminal domain (CTD) kinases are key elements in the control of mRNA synthesis. Yeast CTD kinase I (CTDK-I), is a non-essential complex involved in the regulation of mRNA synthesis at the level of transcription elongation, pre-mRNA 3' formation and nuclear export. Here, we report that CTDK-I is also involved in ribosomal RNA synthesis. We show that CTDK-I is localized in part in the nucleolus. In its absence, nucleolar structure and RNA polymerase I transcription are affected. In vitro experiments show an impairment of the Pol I transcription machinery. Remarkably, RNA polymerase I co-precipitates from cellular extracts with Ctk1, the kinase subunit of the CTDK-I complex. In vitro analysis further demonstrates a direct interaction between RNA polymerase I and Ctk1. The results suggest that CTDK-I might participate in the regulation of distinct nuclear transcriptional machineries, thus playing a role in the adaptation of the global transcriptional response to growth signalling.
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Affiliation(s)
- Céline Bouchoux
- Service de Biochimie et Génétique Moléculaire, CEA/Saclay, 91191 Gif/Yvette, France
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31
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Güldener U, Koehler GJ, Haussmann C, Bacher A, Kricke J, Becher D, Hegemann JH. Characterization of the Saccharomyces cerevisiae Fol1 protein: starvation for C1 carrier induces pseudohyphal growth. Mol Biol Cell 2004; 15:3811-28. [PMID: 15169867 PMCID: PMC491839 DOI: 10.1091/mbc.e03-09-0680] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Tetrahydrofolate (vitamin B9) and its folate derivatives are essential cofactors in one-carbon (C1) transfer reactions and absolutely required for the synthesis of a variety of different compounds including methionine and purines. Most plants, microbial eukaryotes, and prokaryotes synthesize folate de novo. We have characterized an important enzyme in this pathway, the Saccharomyces cerevisiae FOL1 gene. Expression of the budding yeast gene FOL1 in Escherichia coli identified the folate biosynthetic enzyme activities dihydroneopterin aldolase (DHNA), 7,8-dihydro-6-hydroxymethylpterin-pyrophosphokinase (HPPK), and dihydropteroate synthase (DHPS). All three enzyme activities were also detected in wild-type yeast strains, whereas fol1Delta deletion strains only showed background activities, thus demonstrating that Fol1p catalyzes three sequential steps of the tetrahydrofolate biosynthetic pathway and thus is the central enzyme of this pathway, which starting from GTP consists of seven enzymatic reactions in total. Fol1p is exclusively localized to mitochondria as shown by fluorescence microscopy and immune electronmicroscopy. FOL1 is an essential gene and the nongrowth phenotype of the fol1 deletion leads to a recessive auxotrophy for folinic acid (5'-formyltetrahydrofolate). Growth of the fol1Delta deletion strain on folinic acid-supplemented rich media induced a dimorphic switch with haploid invasive and filamentous pseudohyphal growth in the presence of glucose and ammonium, which are known suppressors of filamentous and invasive growth. The invasive growth phenotype induced by the depletion of C1 carrier is dependent on the transcription factor Ste12p and the flocullin/adhesin Flo11p, whereas the filamentation phenotype is independent of Ste12p, Tec1p, Phd1p, and Flo11p, suggesting other signaling pathways as well as other adhesion proteins.
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Affiliation(s)
- Ulrich Güldener
- Heinrich-Heine-Universität, Funktionelle Genomforschung der Mikroorganismen, 40225 Düsseldorf, Germany
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Jenkin GA, Stinear TP, Johnson PDR, Davies JK. Subtractive hybridization reveals a type I polyketide synthase locus specific to Mycobacterium ulcerans. J Bacteriol 2004; 185:6870-82. [PMID: 14617651 PMCID: PMC262701 DOI: 10.1128/jb.185.23.6870-6882.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium ulcerans causes Buruli ulcer, the third most prevalent mycobacterial infection of immunocompetent humans after tuberculosis and leprosy. Recent work has shown that the production by M. ulcerans of mycolactone, a novel polyketide, may partly explain the pathogenesis of Buruli ulcer. To search for the genetic basis of virulence in M. ulcerans, we took advantage of the close genetic relationship between M. ulcerans and Mycobacterium marinum by performing genomic suppressive subtractive hybridization of M. ulcerans with M. marinum. We identified several DNA fragments specific to M. ulcerans, in particular, a type I polyketide synthase locus with a highly repetitive modular arrangement. We postulate that this locus is responsible for the synthesis of mycolactone in M. ulcerans.
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Affiliation(s)
- Grant A Jenkin
- Bacterial Pathogenesis Research Group, Department of Microbiology, Monash University, Clayton, Victoria, Australia
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Bolser D, Dafas P, Harrington R, Park J, Schroeder M. Visualisation and graph-theoretic analysis of a large-scale protein structural interactome. BMC Bioinformatics 2003; 4:45. [PMID: 14531933 PMCID: PMC272926 DOI: 10.1186/1471-2105-4-45] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Accepted: 10/08/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Large-scale protein interaction maps provide a new, global perspective with which to analyse protein function. PSIMAP, the Protein Structural Interactome Map, is a database of all the structurally observed interactions between superfamilies of protein domains with known three-dimensional structure in the PDB. PSIMAP incorporates both functional and evolutionary information into a single network. RESULTS We present a global analysis of PSIMAP using several distinct network measures relating to centrality, interactivity, fault-tolerance, and taxonomic diversity. We found the following results: Centrality: we show that the center and barycenter of PSIMAP do not coincide, and that the superfamilies forming the barycenter relate to very general functions, while those constituting the center relate to enzymatic activity. Interactivity: we identify the P-loop and immunoglobulin superfamilies as the most highly interactive. We successfully use connectivity and cluster index, which characterise the connectivity of a superfamily's neighbourhood, to discover superfamilies of complex I and II. This is particularly significant as the structure of complex I is not yet solved. Taxonomic diversity: we found that highly interactive superfamilies are in general taxonomically very diverse and are thus amongst the oldest. Fault-tolerance: we found that the network is very robust as for the majority of superfamilies removal from the network will not break up the network. CONCLUSIONS Overall, we can single out the P-loop containing nucleotide triphosphate hydrolases superfamily as it is the most highly connected and has the highest taxonomic diversity. In addition, this superfamily has the highest interaction rank, is the barycenter of the network (it has the shortest average path to every other superfamily in the network), and is an articulation vertex, whose removal will disconnect the network. More generally, we conclude that the graph-theoretic and taxonomic analysis of PSIMAP is an important step towards the understanding of protein function and could be an important tool for tracing the evolution of life at the molecular level.
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Affiliation(s)
- Dan Bolser
- Dunn Human Nutrition Unit, Medical Research Council, Cambridge CB2 2XY, UK
| | - Panos Dafas
- Department of Computing, City University, London EC1V 0HB, UK
| | - Richard Harrington
- Dunn Human Nutrition Unit, Medical Research Council, Cambridge CB2 2XY, UK
| | - Jong Park
- Dunn Human Nutrition Unit, Medical Research Council, Cambridge CB2 2XY, UK
- Department of BioSystems, Korea Advanced Institute of Science and Technology, Korea
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Abstract
Allosteric activation of 5(')-AMP-activated protein kinase (AMPK) is currently of interest as an approach for the treatment of metabolic disorders because AMPK plays multiple roles in glucose and lipid metabolism. The availability of ultrafast, ultrasensitive, and robust assays suited to high-throughput screening (HTS) is key to obtaining small-molecule AMPK activators. In the absence of high-affinity and selective antiphospho Ser/Thr antibodies for AMPK substrates, we have developed two homogeneous AMPK assays with the commercially available antibody Anti-pS(133)-CREB and an engineered peptide ACC-CREBp. Anti-pS(133)-CREB antibody was raised against the phospho-CREB peptide derived from cAMP response element binding protein (CREB). ACC-CREBp was a variant (Arg to Pro) of ACC-CREB, a hybrid peptide consisting of a 9-amino-acid peptide from rat acetyl-CoA carboxylase (ACC), CREB peptide, and the addition of two hydrophobic Leu residues. ACC-CREBp showed increased suitability as a substrate for AMPK, eliminated phosphorylation by PKA, and preserved antibody binding. The homogeneous time-resolved fluorescence and AlphaScreen AMPK assays were developed using both Anti-pS(133)-CREB antibody and ACC-CREBp that are either labeled with a fluorescent probe or linked to a photoactivated bead, respectively. Thus, ACC-CREBp phosphorylation can be measured as a signal change resulting from the formation of antibody-antigen complex. This approach of adapting known antibody and antigenic peptide pairs to monitor alternate Ser/Thr kinases may be of general use.
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Affiliation(s)
- Ying Li
- Department of Metabolic Disorders-Diabetes, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA
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35
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Abstract
A method is introduced for the analysis of nearest neighbor distances between immunogold particles marking proteins on electron micrographs. Deviation from the distribution that is predicted by chance indicates co-localization of the labeled species, and the potential for productive interaction in vivo. Application of this method to the analysis of nearest neighbor distances in experiments with pea leaf thin sections and isozyme-directed antibodies indicates that glyceraldehyde-3-P dehydrogenase is located near P-glycerate kinase and near aldolase in the chloroplast stroma, consistent with the notion that these enzymes are part of a multi-enzyme photosynthetic CO(2)-fixation complex in situ.
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Affiliation(s)
- James B Anderson
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
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Abstract
Arsenate reductase (ArsC) from Staphylococcus aureus plasmid pI258 catalyzes the reduction of arsenate to arsenite and plays a role in bacterial heavy metal resistance. The high resolution x-ray structure of ArsC reveals the atomic details of the K+ binding site situated next to the catalytic P-loop structural motif of this redox enzyme. A full thermodynamic study of the binding characteristics of a series of monovalent cations (Li+, Na+, K+, Rb+, and Cs+) and their influence on the thermal stability of ArsC was performed with isothermal titration calorimetry, circular dichroism spectroscopy, and differential scanning calorimetry. Potassium has the largest affinity with a Ka of 3.8 x 10(3) m(-1), and the effectiveness of stabilization of ArsC by monovalent cations follows the binding affinity order: K+ > Rb+ > Cs+ > Na+ > Li+. A mutagenesis study on the K+ binding side chains showed that Asn-13 and Asp-65 are essential for potassium binding, but the impact on the stability of ArsC was the most extreme when mutating Ser-36. Additionally, the thermal stabilization by K+ is significantly reduced in the case of the ArsC E21A mutant, showing the importance of a Glu-21-coordinated water molecule in its contact with K+. Although potassium is not essential for catalysis, in its presence the kcat/KM increases with a factor of 5. Altogether, the interaction of K+ with specific residues in ArsC is an enthalpydriven process that stabilizes ArsC and increases the specific activity of this redox enzyme.
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Affiliation(s)
- Nina Lah
- Department Ultrastructure, Vlaams interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Pleinlaan 2, Belgium.
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Abstract
BACKGROUND Fertilization in mammals comprises the sequential interactions of the sperm with the cumulus oophorus, zona pellucida, and oocyte plasma membrane. Here we investigate proteasome activity in human sperm and its possible involvement during the fertilization process. METHODS Proteasome activity was measured in intact sperm and in sperm extracts using the fluorogenic substrate Suc-Leu-Leu-Val-Tyr-AMC, in the presence or absence of the specific proteasome inhibitor, clasto-lactacystin beta-lactone. The participation of the proteasome was evaluated during (i) sperm-zona binding using the hemizona assay; (ii) zona pellucida-induced acrosome reactions with a pulse and chase design; (iii) progesterone-induced acrosome reactions incubating overnight capacitated sperm with progesterone; and (iv) progesterone-induced Ca(2+) influx using fura-2AM. RESULTS Intact sperm and sperm extracts possessed proteasome activity, which was susceptible to inhibition by clasto-lactacystin beta-lactone. Sperm-zona binding was not inhibited by clasto-lactacystin beta-lactone. However, both zona pellucida- and progesterone-induced acrosome reactions were inhibited by clasto-lactacystin beta-lactone. The proteasome inhibitor also blocked the sustained phase of the Ca(2+) influx provoked by progesterone but not the peak. CONCLUSION The human sperm proteasome is involved in the exocytosis of the acrosome, perhaps in events upstream of the plateau phase of the Ca(2+) influx.
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Affiliation(s)
- Patricio Morales
- Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Avda, Angamos 601, P.O. Box 170, Antofagasta, Chile.
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Fergusson KM, Saint CP. Multiplex PCR assay for Cylindrospermopsis raciborskii and cylindrospermopsin-producing cyanobacteria. Environ Toxicol 2003; 18:120-5. [PMID: 12635100 DOI: 10.1002/tox.10108] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Water bodies are routinely monitored for the presence of potentially toxic cyanobacteria; however, the methodology for confirming toxicity is currently complex and expensive. Here we describe the application of gene-based technology to rapidly identify cylindrospermopsin-producing cyanobacteria, specifically, Cylindrospermopsis raciborskii. A multiplex polymerase chain reaction (PCR) test was developed that simultaneously identified polyketide synthase (pks) and peptide synthetase (ps) determinants associated with cylindrospermopsin production and distinguished C. raciborskii from other cylindrospermopsin-producing cyanobacteria of the species Anabaena bergii and Aphanizomenon ovalisporum, by targeting the rpoC1 gene. Twenty-one C. raciborskii, 5 A. bergii, 10 Aph. ovalisporum isolates and 3 environmental samples all yielded PCR results consistent with their toxicological status, as assessed by high-performance liquid chromatography coupled to mass spectrometry or matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, and C. raciborskii was always correctly identified. The PCR test is a rapid, reliable, and economical way of assessing the toxic potential of cyanobacterial blooms formed by these organisms.
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Affiliation(s)
- Kim M Fergusson
- Cooperative Research Centre for Water Quality and Treatment, Australian Water Quality Centre, SA Water Corporation, Private Mail Bag 3, Salisbury, South Australia 5108, Australia
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39
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Abstract
An acute bout of exercise increases skeletal muscle glucose uptake, improves glucose homeostasis and insulin sensitivity, and enhances muscle oxidative capacity. Recent studies have shown an association between these adaptations and the energy-sensing 5' AMP-activated protein kinase (AMPK), the activity of which is increased in response to exercise. Activation of AMPK has been associated with enhanced expression of key metabolic proteins such as GLUT-4, hexokinase II (HKII), and mitochondrial enzymes, similar to exercise. It has been hypothesized that AMPK might regulate gene and protein expression through direct interaction with the nucleus. The purpose of this study was to determine if nuclear AMPK alpha(2) content in human skeletal muscle was increased by exercise. Following 60 min of cycling at 72 +/- 1% of VO(2peak) in six male volunteers (20.6 +/- 2.1 years; 72.9 +/- 2.1 kg; VO(2peak) = 3.62 +/- 0.18 l/min), nuclear AMPK alpha(2) content was increased 1.9 +/- 0.4-fold (P = 0.024). There was no change in whole-cell AMPK alpha(2) content or AMPK alpha(2) mRNA abundance. These results suggest that nuclear translocation of AMPK might mediate the effects of exercise on skeletal muscle gene and protein expression.
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Affiliation(s)
- Sean L McGee
- Exercise, Muscle and Metabolism Unit, School of Health Sciences, Deakin University, Burwood, Australia
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40
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Talwalkar A, Kailasapathy K, Hourigan J, Peiris P, Arumugaswamy R. An improved method for the determination of NADH oxidase in the presence of NADH peroxidase in lactic acid bacteria. J Microbiol Methods 2003; 52:333-9. [PMID: 12531502 DOI: 10.1016/s0167-7012(02)00189-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The complexity of the coupled NADH oxidase-NADH peroxidase enzyme system in lactic acid bacteria makes it difficult to simultaneously determine the individual levels of both these enzymes spectrophotometrically. This study describes an improved assay to accurately determine low concentrations of NADH oxidase from enzyme suspensions containing NADH oxidase and NADH peroxidase. For the standardisation of the assay, pure NADH oxidase and NADH peroxidase were mixed in various proportions and the percentage recovery was estimated by both the currently available assay as well as by the improved assay reported in this study. The recovery of NADH oxidase using the currently available assay ranged from as low as -200% to as high as +102% as against 90-102% in the improved assay. The recovery percentage of NADH peroxidase ranged from 91% to 112% in both assays. The slopes of NADH oxidation by cell-free extracts of six lactic acid bacteria were also measured by both assays for the estimation of NADH oxidase and NADH peroxidase levels. The improved assay can further distinguish between NADH-H(2)O oxidase and NADH-H(2)O(2) oxidase and was successfully applied to identify the type of NADH oxidase in the lactic acid bacteria tested.
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Affiliation(s)
- Akshat Talwalkar
- Centre for Advanced Food Research, University of Western Sydney-Hawkesbury, Locked Bag 1797, NSW 1797, Australia
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41
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Gloerich J, Denis S, van Grunsven EG, Dacremont G, Wanders RJA, Ferdinandusse S. A novel HPLC-based method to diagnose peroxisomal D-bifunctional protein enoyl-CoA hydratase deficiency. J Lipid Res 2003; 44:640-4. [PMID: 12562856 DOI: 10.1194/jlr.d200039-jlr200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
D-bifunctional protein (D-BP) plays an indispensable role in peroxisomal beta-oxidation, and its inherited deficiency in humans is associated with severe clinical abnormalities. Three different subtypes of D-BP deficiency can be distinguished: 1) a complete deficiency of D-BP (type I), 2) an isolated D-BP enoyl-CoA hydratase deficiency (type II), and 3) an isolated D-BP 3-hydroxyacyl-CoA dehydrogenase deficiency (type III). In this study, we developed a method to measure D-BP dehydrogenase activity independent of D-BP hydratase (D-BP HY) activity to distinguish between D-BP deficiency type I and type II, which until now was only possible by mutation analysis. For this assay, the hydratase domain of D-BP was expressed in the yeast Saccharomyces cerevisiae. After a coincubation of yeast homogenate expressing D-BP HY with fibroblast homogenate of patients using the enoyl-CoA ester of the bile acid intermediate trihydroxycholestanoic acid as substrate, D-BP dehydrogenase activity was measured. Fibroblasts of patients with a D-BP deficiency type II displayed D-BP dehydrogenase activity, whereas type I and type III patients did not. This newly developed assay to measure D-BP dehydrogenase activity in fibroblast homogenates provides a quick and reliable method to assign patients with deficient D-BP HY activity to the D-BP deficiency subgroups type I or type II.
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Affiliation(s)
- Jolein Gloerich
- University of Amsterdam, Academic Medical Center, Department of Clinical Chemistry, Laboratory for Genetic Metabolic Diseases (F0-224), P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
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42
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Abstract
'Myofibrillar myopathy' defines a myopathic condition with focal myofibrillar destruction and accumulation of degraded myofibrillar elements. Despite the fact that a number of mutations in different genes as well as cytotoxic agents lead to the disease, abnormal accumulation of desmin is a typical, common feature. Pathological changes of mitochondrial morphology and function have been observed in animal models with intermediate filament pathology. Therefore, in the present study we tested for mitochondrial pathology in skeletal muscle of five patients with the pathohistological diagnosis of myofibrillar myopathy. Screening for large-scale mtDNA deletions and the frequent MERRF (myoclonic epilepsy; ragged red fibres) and MELAS (mitochondrial encephalomyopathy; lactic acidosis; stroke) point mutations was negative in all patients. Histologically, all muscle biopsies showed nonspecific abnormalities of the oxidative/mitochondrial enzyme stainings (histochemistry for reduced nicotinamide adenine dinucleotide, succinic dehydrogenase, cytochrome c oxidase), only one of them had ragged red fibres and a significant number of cytochrome c oxidase-negative fibres. Upon biochemical investigation, four of our patients showed pathologically low respiratory chain complex I activities. Only one of our patients had a pathologically low complex IV activity, while the measurements of the others were within low normal range. The single patient with pathological values for both complex I and IV was the one with the clear histological hallmarks (ragged red and cytochrome c oxidase-negative fibres) of mitochondrial pathology. She also was the only patient with clinical signs hinting at a mitochondrial disorder. Together with data from observations in desmin- and plectin-deficient mice, our results support the view that desmin intermediate filament pathology in these cases is closely linked to mitochondrial dysfunction in skeletal muscle.
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Affiliation(s)
- Jens Reimann
- Department of Neurology, University of Bonn, Germany.
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43
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Abstract
Menkes protein (ATP7A) is a P-type ATPase involved in copper uptake and homeostasis. Disturbed copper homeostasis occurs in patients with Menkes disease, an X-linked disorder characterized by mental retardation, neurodegeneration, connective tissue disorders, and early childhood death. Mutations in ATP7A result in malfunction of copper-requiring enzymes, such as tyrosinase and copper/zinc superoxide dismutase. The first step of the two-step amidation reaction carried out by peptidylglycine alpha-amidating monooxygenase (PAM) also requires copper. We used tissue from wild-type rats and mice and an ATP7A-specific antibody to determine that ATP7A is expressed at high levels in tissues expressing high levels of PAM. ATP7A is largely localized to the trans Golgi network in pituitary endocrine cells. The Atp7a mouse, bearing a mutation in the Atp7a gene, is an excellent model system for examining the consequences of ATP7A malfunction. Despite normal levels of PAM protein, levels of several amidated peptides were reduced in pituitary and brain extracts of Atp7a mice, demonstrating that PAM function is compromised when ATP7A is inactive. Based on these results, we conclude that a reduction in the ability of PAM to produce bioactive end-products involved in neuronal growth and development could contribute to many of the biological effects associated with Menkes disease.
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Affiliation(s)
- Tami C Steveson
- Department of Neuroscience,, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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44
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Neves AR, Ramos A, Costa H, van Swam II, Hugenholtz J, Kleerebezem M, de Vos W, Santos H. Effect of different NADH oxidase levels on glucose metabolism by Lactococcus lactis: kinetics of intracellular metabolite pools determined by in vivo nuclear magnetic resonance. Appl Environ Microbiol 2002; 68:6332-42. [PMID: 12450858 PMCID: PMC134407 DOI: 10.1128/aem.68.12.6332-6342.2002] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three isogenic strains of Lactococcus lactis with different levels of H(2)O-forming NADH oxidase activity were used to study the effect of oxygen on glucose metabolism: the parent strain L. lactis MG1363, a NOX(-) strain harboring a deletion of the gene coding for H(2)O-forming NADH oxidase, and a NOX(+) strain with the NADH oxidase activity enhanced by about 100-fold. A comprehensive description of the metabolic events was obtained by using (13)C nuclear magnetic resonance in vivo. The most noticeable results of this study are as follows: (i) under aerobic conditions the level of fructose 1,6-bisphosphate [Fru(1,6)P(2)] was lower than the level under anaerobic conditions, and the rate of Fru(1,6)P(2) depletion was very high; (ii) the levels of 3-phosphoglycerate and phosphoenolpyruvate were considerably enhanced under aerobic conditions and significantly lower in the NOX(-) strain; and (iii) the glycolytic flux decreased in the presence of saturating levels of oxygen, but it was not altered in response to changes in the NADH oxidase activity. In particular, the observation that the glycolytic flux was not enhanced in the NOX(+) strain indicated that glycolytic flux was not primarily determined by the level of NADH in the cell. The patterns of end products were identical for the NOX(-) and parent strains; in the NOX(+) strain the carbon flux was diverted to the production of alpha-acetolactate-derived compounds, and at a low pH this strain produced diacetyl at concentrations up to 1.6 mM. The data were integrated with the goal of identifying the main regulatory aspects of glucose metabolism in the presence of oxygen.
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Affiliation(s)
- Ana Rute Neves
- Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa and Instituto de Biologia Experimental e Tecnológica, 2780-156 Oeiras, Portugal
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45
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Abstract
We have studied the intracellular distribution of proteasome subunits, corresponding to the catalytic (20S) core and the regulatory (19S) cap, in the extracellular protozoan parasite Entamoeba histolytica. Contrary to all cell types described to date, notably mammalian and yeast, in which the proteasome is found in the nucleus and actively imported into it, microscopic analysis and subcellular fractionation of E. histolytica trophozoites show that the proteasome is absent from the nucleus of these cells. We speculate that, given the relative abundance of mono- and multinucleated trophozoites in culture, a relationship may exist between this unusual distribution of the proteasome and the frequent lack of synchrony between karyo- and cytokinesis in this primitive eukaryote.
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Affiliation(s)
- Ricardo Sánchez
- Instituto de Biotechnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, Morelos 62210, Mexico
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46
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Abstract
Amyotrophic lateral sclerosis is a fatal neurodegenerative disease that causes degeneration of motoneurons. Mutation of Cu,Zn superoxide dismutase (SOD1) is one cause for this disease. In mice, expression of mutant protein causes motoneuron degeneration and paralysis resembling the human disease. Morphological change, indicative of mitochondrial damage, occurs at early stages of the disease. To determine whether mitochondrial function changes during the course of disease progression, enzyme activities of mitochondrial electron transport chain in spinal cords from mice at different disease stages were measured using three different methods: spectrophotometric assay, in situ histochemical enzyme assay, and blue native gel electrophoresis combined with in-gel histochemical reaction. The enzyme activities were decreased in the spinal cord, particularly in the ventral horn, beginning at early disease stages. This decrease persisted throughout the course of disease progression. This decrease was not detected in the spinal cords of non-transgenic animals, of mice expressing the wild-type protein, and in cerebellum and dorsal horn of the spinal cords from mice expressing mutant protein. These results demonstrate a functional defect in mitochondria in the ventral horn region and support the view that mitochondrial damage plays a role in mutant SOD1-induced motoneuron degeneration pathway.
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Affiliation(s)
- Cheolwha Jung
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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47
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Frangakis AS, Böhm J, Förster F, Nickell S, Nicastro D, Typke D, Hegerl R, Baumeister W. Identification of macromolecular complexes in cryoelectron tomograms of phantom cells. Proc Natl Acad Sci U S A 2002; 99:14153-8. [PMID: 12391313 PMCID: PMC137853 DOI: 10.1073/pnas.172520299] [Citation(s) in RCA: 180] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electron tomograms of intact frozen-hydrated cells are essentially three-dimensional images of the entire proteome of the cell, and they depict the whole network of macromolecular interactions. However, this information is not easily accessible because of the poor signal-to-noise ratio of the tomograms and the crowded nature of the cytoplasm. Here, we describe a template matching algorithm that is capable of detecting and identifying macromolecules in tomographic volumes in a fully automated manner. The algorithm is based on nonlinear cross correlation and incorporates elements of multivariate statistical analysis. Phantom cells, i.e., lipid vesicles filled with macromolecules, provide a realistic experimental scenario for an assessment of the fidelity of this approach. At the current resolution of approximately 4 nm, macromolecules in the size range of 0.5-1 MDa can be identified with good fidelity.
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Affiliation(s)
- Achilleas S Frangakis
- Max-Planck-Institut für Biochemie, Molekulare Strukturbiologie, Am Klopferspitz 18a, 82152 Martinsried, Germany.
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48
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Schwartz B, Markwalder JA, Seitz SP, Wang Y, Stein RL. A kinetic characterization of the glycosyltransferase activity of Eschericia coli PBP1b and development of a continuous fluorescence assay. Biochemistry 2002; 41:12552-61. [PMID: 12369847 DOI: 10.1021/bi026205x] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bacterial cell wall is a polymer consisting of alternating N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) units, cross-linked via peptides appended to MurNAc. The final steps in the formation of cell wall, also referred to as murein, are catalyzed by high-molecular-weight, class A penicillin-binding proteins (PBPs). These bifunctional enzymes catalyze both glycosyltransfer, to form the carbohydrate backbone of murein, and transpeptidation, to form the interstrand peptide linkages. Using PBP1b from Eschericia coli, an in vitro kinetic characterization of the glycosyltransfer reaction was carried out. Initial studies with unlabeled substrate (Lipid II) revealed that activity is strongly influenced by DMSO, as well as metal and detergent. In addition, a continuous fluoresence assay was developed and used to determine the effect of pH on the reaction. A single basic residue was titrated, with a pK(a) of 7.0. Taken together, these data suggest a mechanism for PBP1b where the glycosyltransfer reaction is catalyzed by the concerted effect of an active site base to deprotonate the glycosyl acceptor and a divalent metal to assist departure of the leaving group of the glycosyl donor.
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Affiliation(s)
- Benjamin Schwartz
- Department of Chemical and Physical Sciences, Bristol-Myers Squibb Company, Wilmington, Delaware 19880, USA.
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49
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Abstract
The osmotolerant fungus Aspergillus chevalieri tolerates up to 80% sucrose concentration in the growth medium. At 50% sucrose the growth rate is 1.5-fold higher than in control (3% sucrose), at 80% sucrose it drops to 30% of the control level. Total proteins and lipids in the mitochondrial fractions obtained from the mycelium rise with increasing sucrose concentration during growth (2.6 and 2.1 times at 80% sucrose). The rate of respiration by whole cells and mitochondrial fractions increases with increased sucrose level in the growth medium. The activity of respiratory enzymes, such as succinate dehydrogenase, cytochrome oxidase, NADH oxidase and succinate oxidase, were also higher in cells grown in the presence of elevated sucrose concentrations. The largest increase was observed with NADH dehydrogenase. A. chevalieri cells grown at high osmotic stress exhibited enlarged mitochondria. The mean mitochondrial diameter at 50 and 80% sucrose was approximately 2.9- and 2.6-fold larger than in the control, respectively. Agarose gel electrophoresis of nucleic acids revealed the presence of high-density bands of RNA in mitochondrial fractions from cells grown at elevated sucrose levels.
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Affiliation(s)
- M A Hefnawy
- Botany Department, Faculty of Science, Menoufia University, Shebin El-Kom, Egypt
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50
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Mittenberg AG, Kulichkova VA, Gauze LN, Konstantinova IM. [Properties of endoribonuclease activity of proteasomes from K562 cells. III. The specific endonuclease activity of ribonucleoprotein particles (alpha-RNP) tightly bound to chromatin and containing 20S proteosomes]. Tsitologiia 2002; 44:364-8. [PMID: 12149780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The present work demonstrates the ability of 20S proteasome-containing, tightly bound to chromatin RNP-particles (alpha-RNP) to endonucleolyse specific messenger RNAs (in particular, human mRNA for p53 gene and mRNA for luciferase from Renilla sp.). The dependence of individual mRNA endonucleolysis by alpha-RNP particles on both the substrate and enzyme was found.
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