Chemotaxis and Binding of Pseudomonas aeruginosa to Scratch-Wounded Human Cystic Fibrosis Airway Epithelial Cells.

Directory of Open Access Journals (Sweden)

Christian Schwarzer

Full Text Available Confocal imaging was used to characterize interactions of Pseudomonas aeruginosa (PA, expressing GFP or labeled with Syto 11 with CF airway epithelial cells (CFBE41o-, grown as confluent monolayers with unknown polarity on coverglasses in control conditions and following scratch wounding. Epithelia and PAO1-GFP or PAK-GFP (2 MOI were incubated with Ringer containing typical extracellular salts, pH and glucose and propidium iodide (PI, to identify dead cells. PAO1 and PAK swam randomly over and did not bind to nonwounded CFBE41o- cells. PA migrated rapidly (began within 20 sec, maximum by 5 mins and massively (10-80 fold increase, termed "swarming", but transiently (random swimming after 15 mins, to wounds, particularly near cells that took up PI. Some PA remained immobilized on cells near the wound. PA swam randomly over intact CFBE41o- monolayers and wounded monolayers that had been incubated with medium for 1 hr. Expression of CFTR and altered pH of the media did not affect PA interactions with CFBE41o- wounds. In contrast, PAO1 swarming and immobilization along wounds was abolished in PAO1 (PAO1ΔcheYZABW, no expression of chemotaxis regulatory components cheY, cheZ, cheA, cheB and cheW and greatly reduced in PAO1 that did not express amino acid receptors pctA, B and C (PAO1ΔpctABC and in PAO1 incubated in Ringer containing a high concentration of mixed amino acids. Non-piliated PAKΔpilA swarmed normally towards wounded areas but bound infrequently to CFBE41o- cells. In contrast, both swarming and binding of PA to CFBE41o- cells near wounds were prevented in non-flagellated PAKΔfliC. Data are consistent with the idea that (i PA use amino acid sensor-driven chemotaxis and flagella-driven swimming to swarm to CF airway epithelial cells near wounds and (ii PA use pili to bind to epithelial cells near wounds.

Structural characteristics of epicentral areas in Central Europe: study case Cheb Basin (Czech Republic)

Science.gov (United States)

Bankwitz, P.; Schneider, G.; Kämpf, H.; Bankwitz, E.

2003-03-01

The earthquake distribution pattern of Central Europe differs systematically from the neighbouring areas of NW and southern Europe regarding the fault plane kinematics. Within a belt between the French Massif Central and the northern part of the Bohemian Massif (1000 km) sinistral faulting along N-S zones dominates on the contrary to the Alps and their foreland with common bookshelf shears. One of the prominent N-S structures is the Regensburg-Leipzig-Rostock Zone (A) with several epicentral areas, where the main seismic center occurs in the northern Cheb Basin (NW Bohemia). The study demonstrates new structural results for the swarm-quake region in NW-Bohemia, especially for the Nový Kostel area in the Cheb Basin. There the N-S-trending newly found Počatky-Plesná zone (PPZ) is identical with the main earthquake line. The PPZ is connected with a mofette line between Hartušov and Bublák with evidence for CO 2 degassing from the subcrustal mantle. The morphologically more prominent Mariánské Lázně fault (MLF) intersects the PPZ obliquely under an acuate angle. In the past the MLF was supposed to be the tectonic structure connected with the epicentral area of Nový Kostel. But evidence from the relocated hypocentres along the PPZ (at 7-12 kms depth) indicate that the MLF is seismically non-active. Asymmetric drainage patterns of the Cheb Basin are caused by fault related movement along Palaeozoic basement faults which initiate a deformation of the cover (Upper Pliocene to Holocene basin filling). The PPZ forms an escarpment in Pliocene and Pleistocene soft rock and is supposingly acting as an earthquake zone since late Pleistocene time. The uppermost Pleistocene of 0.12-0.01 Ma deposited only in front of the fault scarp dates the fault activity. The crossing faults envelope crustal wedges under different local stress conditions. Their intersection line forms a zone beginning at the surface near Nový Kostel, dipping south with increasing depth, probably down

Measuring Borrelia burgdorferi Motility and Chemotaxis.

Science.gov (United States)

Zhang, Kai; Li, Chunhao

2018-01-01

Swimming plate, cell motion tracking, and capillary tube assays are very useful tools to quantitatively measure bacterial motility and chemotaxis. These methods were modified and applied to study Borrelia burgdorferi motility and chemotaxis. By using these methods, numerous motility and chemotaxis mutants have been characterized and several chemoattractants were identified. With the assistance of these tools, the role of motility and chemotaxis in the pathogenicity of B. burgdorferi has been established. In addition, these tools also facilitate the study of motility and chemotaxis in other spirochetes.

A novel antagonist of CRTH2 blocks eosinophil release from bone marrow, chemotaxis and respiratory burst

DEFF Research Database (Denmark)

Royer, J F; Schratl, P; Lorenz, S

2007-01-01

developed small molecule antagonist of CRTH2, Cay10471, on eosinophil function with respect to recruitment, respiratory burst and degranulation. METHODS: Chemotaxis of guinea pig bone marrow eosinophils and human peripheral blood eosinophils were determined using microBoyden chambers. Eosinophil release...... from bone marrow was investigated in the in situ perfused guinea pig hind limb preparation. Respiratory burst and degranulation were measured by flow cytometry. RESULTS: Cay10471 bound with high affinity to recombinant human and guinea pig CRTH2, but not DP, receptors. The antagonist prevented the PGD......(2)-induced release of eosinophils from guinea pig bone marrow, and inhibited the chemotaxis of guinea pig bone marrow eosinophils and human peripheral blood eosinophils. Pretreatment with PGD(2) primed eosinophils for chemotaxis towards eotaxin, and this effect was prevented by Cay10471. In contrast...

β-Arrestin-2-Dependent Signaling Promotes CCR4-mediated Chemotaxis of Murine T-Helper Type 2 Cells.

Science.gov (United States)

Lin, Rui; Choi, Yeon Ho; Zidar, David A; Walker, Julia K L

2018-06-01

Allergic asthma is a complex inflammatory disease that leads to significant healthcare costs and reduction in quality of life. Although many cell types are implicated in the pathogenesis of asthma, CD4 + T-helper cell type 2 (Th2) cells are centrally involved. We previously reported that the asthma phenotype is virtually absent in ovalbumin-sensitized and -challenged mice that lack global expression of β-arrestin (β-arr)-2 and that CD4 + T cells from these mice displayed significantly reduced CCL22-mediated chemotaxis. Because CCL22-mediated activation of CCR4 plays a role in Th2 cell regulation in asthmatic inflammation, we hypothesized that CCR4-mediated migration of CD4 + Th2 cells to the lung in asthma may use β-arr-dependent signaling. To test this hypothesis, we assessed the effect of various signaling inhibitors on CCL22-induced chemotaxis using in vitro-polarized primary CD4 + Th2 cells from β-arr2-knockout and wild-type mice. Our results show, for the first time, that CCL22-induced, CCR4-mediated Th2 cell chemotaxis is dependent, in part, on a β-arr2-dependent signaling pathway. In addition, we show that this chemotactic signaling mechanism involves activation of P-p38 and Rho-associated protein kinase. These findings point to a proinflammatory role for β-arr2-dependent signaling and support β-arr2 as a novel therapeutic target in asthma.

Increased C-C chemokine receptor 2 gene expression in monocytes of severe obstructive sleep apnea patients and under intermittent hypoxia.

Science.gov (United States)

Chuang, Li-Pang; Chen, Ning-Hung; Lin, Shih-Wei; Chang, Ying-Ling; Liao, Hsiang-Ruei; Lin, Yu-Sheng; Chao, I-Ju; Lin, Yuling; Pang, Jong-Hwei S

2014-01-01

Obstructive sleep apnea (OSA) is known to be a risk factor of coronary artery disease. The chemotaxis and adhesion of monocytes to the endothelium in the early atherosclerosis is important. This study aimed to investigate the effect of intermittent hypoxia, the hallmark of OSA, on the chemotaxis and adhesion of monocytes. Peripheral blood was sampled from 54 adults enrolled for suspected OSA. RNA was prepared from the isolated monocytes for the analysis of C-C chemokine receptor 2 (CCR2). The effect of intermittent hypoxia on the regulation and function of CCR2 was investigated on THP-1 monocytic cells and monocytes. The mRNA and protein expression levels were investigated by RT/real-time PCR and western blot analysis, respectively. Transwell filter migration assay and cell adhesion assay were performed to study the chemotaxis and adhesion of monocytes. Monocytic CCR2 gene expression was found to be increased in severe OSA patients and higher levels were detected after sleep. Intermittent hypoxia increased the CCR2 expression in THP-1 monocytic cells even in the presence of TNF-α and CRP. Intermittent hypoxia also promoted the MCP-1-mediated chemotaxis and adhesion of monocytes to endothelial cells. Furthermore, inhibitor for p42/44 MAPK or p38 MAPK suppressed the activation of monocytic CCR2 expression by intermittent hypoxia. This is the first study to demonstrate the increase of CCR2 gene expression in monocytes of severe OSA patients. Monocytic CCR2 gene expression can be induced under intermittent hypoxia which contributes to the chemotaxis and adhesion of monocytes.

Dictyostelium Chemotaxis studied with fluorescence fluctuation spectroscopy

NARCIS (Netherlands)

Ruchira, A.

2005-01-01

The movement of cells in the direction of a chemical gradient, also known as chemotaxis, is a vital biological process. During chemotaxis, minute extracellular signals are translated into complex cellular responses such as change in morphology and motility. To understand the chemotaxis mechanism at

Chemotaxis-defective mutants of the nematode Caenorhabditis elegans.

Science.gov (United States)

Dusenbery, D B; Sheridan, R E; Russell, R L

1975-06-01

The technique of countercurrent separation has been used to isolate 17 independent chemotaxis-defective mutants of the nematode Caenorhabditis elegans. The mutants, selected to be relatively insensitive to the normally attractive salt NaCl, show varying degrees of residual sensitivity; some are actually weakly repelled by NaCl. The mutants are due to single gene defects, are autosomal and recessive, and identify at least five complementation groups.

A dual-docking microfluidic cell migration assay (D2-Chip) for testing neutrophil chemotaxis and the memory effect.

Science.gov (United States)

Yang, Ke; Wu, Jiandong; Xu, Guoqing; Xie, Dongxue; Peretz-Soroka, Hagit; Santos, Susy; Alexander, Murray; Zhu, Ling; Zhang, Michael; Liu, Yong; Lin, Francis

2017-04-18

Chemotaxis is a classic mechanism for guiding cell migration and an important topic in both fundamental cell biology and health sciences. Neutrophils are a widely used model to study eukaryotic cell migration and neutrophil chemotaxis itself can lead to protective or harmful immune actions to the body. While much has been learnt from past research about how neutrophils effectively navigate through a chemoattractant gradient, many interesting questions remain unclear. For example, while it is tempting to model neutrophil chemotaxis using the well-established biased random walk theory, the experimental proof was challenged by the cell's highly persistent migrating nature. A special experimental design is required to test the key predictions from the random walk model. Another question that has interested the cell migration community for decades concerns the existence of chemotactic memory and its underlying mechanism. Although chemotactic memory has been suggested in various studies, a clear quantitative experimental demonstration will improve our understanding of the migratory memory effect. Motivated by these questions, we developed a microfluidic cell migration assay (so-called dual-docking chip or D 2 -Chip) that can test both the biased random walk model and the memory effect for neutrophil chemotaxis on a single chip enabled by multi-region gradient generation and dual-region cell alignment. Our results provide experimental support for the biased random walk model and chemotactic memory for neutrophil chemotaxis. Quantitative data analyses provide new insights into neutrophil chemotaxis and memory by making connections to entropic disorder, cell morphology and oscillating migratory response.

Strenuous physical exercise adversely affects monocyte chemotaxis

DEFF Research Database (Denmark)

Czepluch, Frauke S; Barres, Romain; Caidahl, Kenneth

2011-01-01

Physical exercise is important for proper cardiovascular function and disease prevention, but it may influence the immune system. We evaluated the effect of strenuous exercise on monocyte chemotaxis. Monocytes were isolated from blood of 13 young, healthy, sedentary individuals participating...... in a three-week training program which consisted of repeated exercise bouts. Monocyte chemotaxis and serological biomarkers were investigated at baseline, after three weeks training and after four weeks recovery. Chemotaxis towards vascular endothelial growth factor-A (VEGF-A) and transforming growth factor...

ARF1 recruits RAC1 to leading edge in neutrophil chemotaxis.

Science.gov (United States)

Mazaki, Yuichi; Onodera, Yasuhito; Higashi, Tsunehito; Horinouchi, Takahiro; Oikawa, Tsukasa; Sabe, Hisataka

2017-10-02

The small GTPase ARF1 mediates membrane trafficking mostly from the Golgi, and is essential for the G protein-coupled receptor (GPCR)-mediated chemotaxis of neutrophils. In this process, ARF1 is activated by the guanine nucleotide exchanger GBF1, and is inactivated by the GTPase-activating protein GIT2. Neutrophils generate the Gβγ-PAK1-αPIX-GIT2 linear complex during GPCR-induced chemotaxis, in which αPIX activates RAC1/CDC42, which then employs PAK1. However, it has remained unclear as to why GIT2 is included in this complex. We investigated the association between ARF1 and RAC1/CDC42 during the fMLP-stimulated chemotaxis of HL60 cells. We found that the silencing of GBF1 significantly impaired the recruitment of RAC1 to the leading edges, but not PAK1, αPIX, RAC2, or CDC42. A significant population of RAC1 colocalized with ARF1 at the leading edges in stimulated cells, whereas fMLP activated both ARF1 and ARF5. Consistently, the silencing of ARF1, but not ARF5, impaired the recruitment of RAC1, whereas the silencing of RAC1 did not affect the recruitment of ARF1 to the leading edges. Our results indicated that the activation of ARF1 triggers the plasma membrane recruitment of RAC1 in GPCR-mediated chemotaxis, which is essential for cortical actin remodeling. Thus, membrane remodeling at the leading edges appears to precede actin remodeling in chemotaxis. Together with the fact that GIT2, which inactivates ARF1, is an integral component of the machinery activating RAC1, we proposed a model in which the ARF1-RAC1 linkage enables the regulation of ARF1 by repetitive on/off cycles during GPCR-mediated neutrophil chemotaxis.

Direct Correlation between Motile Behavior and Protein Abundance in Single Cells.

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Yann S Dufour

2016-09-01

Full Text Available Understanding how stochastic molecular fluctuations affect cell behavior requires the quantification of both behavior and protein numbers in the same cells. Here, we combine automated microscopy with in situ hydrogel polymerization to measure single-cell protein expression after tracking swimming behavior. We characterized the distribution of non-genetic phenotypic diversity in Escherichia coli motility, which affects single-cell exploration. By expressing fluorescently tagged chemotaxis proteins (CheR and CheB at different levels, we quantitatively mapped motile phenotype (tumble bias to protein numbers using thousands of single-cell measurements. Our results disagreed with established models until we incorporated the role of CheB in receptor deamidation and the slow fluctuations in receptor methylation. Beyond refining models, our central finding is that changes in numbers of CheR and CheB affect the population mean tumble bias and its variance independently. Therefore, it is possible to adjust the degree of phenotypic diversity of a population by adjusting the global level of expression of CheR and CheB while keeping their ratio constant, which, as shown in previous studies, confers functional robustness to the system. Since genetic control of protein expression is heritable, our results suggest that non-genetic diversity in motile behavior is selectable, supporting earlier hypotheses that such diversity confers a selective advantage.

A coupled chemotaxis-fluid model: Global existence

KAUST Repository

Liu, Jian-Guo; Lorz, Alexander

2011-01-01

We consider a model arising from biology, consisting of chemotaxis equations coupled to viscous incompressible fluid equations through transport and external forcing. Global existence of solutions to the Cauchy problem is investigated under certain conditions. Precisely, for the chemotaxis-Navier- Stokes system in two space dimensions, we obtain global existence for large data. In three space dimensions, we prove global existence of weak solutions for the chemotaxis-Stokes system with nonlinear diffusion for the cell density.© 2011 Elsevier Masson SAS. All rights reserved.

A coupled chemotaxis-fluid model: Global existence

KAUST Repository

Liu, Jian-Guo

2011-09-01

We consider a model arising from biology, consisting of chemotaxis equations coupled to viscous incompressible fluid equations through transport and external forcing. Global existence of solutions to the Cauchy problem is investigated under certain conditions. Precisely, for the chemotaxis-Navier- Stokes system in two space dimensions, we obtain global existence for large data. In three space dimensions, we prove global existence of weak solutions for the chemotaxis-Stokes system with nonlinear diffusion for the cell density.© 2011 Elsevier Masson SAS. All rights reserved.

A novel Ras-interacting protein required for chemotaxis and cyclic adenosine monophosphate signal relay in Dictyostelium.

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Lee, S; Parent, C A; Insall, R; Firtel, R A

1999-09-01

We have identified a novel Ras-interacting protein from Dictyostelium, RIP3, whose function is required for both chemotaxis and the synthesis and relay of the cyclic AMP (cAMP) chemoattractant signal. rip3 null cells are unable to aggregate and lack receptor activation of adenylyl cyclase but are able, in response to cAMP, to induce aggregation-stage, postaggregative, and cell-type-specific gene expression in suspension culture. In addition, rip3 null cells are unable to properly polarize in a cAMP gradient and chemotaxis is highly impaired. We demonstrate that cAMP stimulation of guanylyl cyclase, which is required for chemotaxis, is reduced approximately 60% in rip3 null cells. This reduced activation of guanylyl cyclase may account, in part, for the defect in chemotaxis. When cells are pulsed with cAMP for 5 h to mimic the endogenous cAMP oscillations that occur in wild-type strains, the cells will form aggregates, most of which, however, arrest at the mound stage. Unlike the response seen in wild-type strains, the rip3 null cell aggregates that form under these experimental conditions are very small, which is probably due to the rip3 null cell chemotaxis defect. Many of the phenotypes of the rip3 null cell, including the inability to activate adenylyl cyclase in response to cAMP and defects in chemotaxis, are very similar to those of strains carrying a disruption of the gene encoding the putative Ras exchange factor AleA. We demonstrate that aleA null cells also exhibit a defect in cAMP-mediated activation of guanylyl cyclase similar to that of rip3 null cells. A double-knockout mutant (rip3/aleA null cells) exhibits a further reduction in receptor activation of guanylyl cyclase, and these cells display almost no cell polarization or movement in cAMP gradients. As RIP3 preferentially interacts with an activated form of the Dictyostelium Ras protein RasG, which itself is important for cell movement, we propose that RIP3 and AleA are components of a Ras

Early osteoinductive human bone marrow mesenchymal stromal/stem cells support an enhanced hematopoietic cell expansion with altered chemotaxis- and adhesion-related gene expression profiles

Energy Technology Data Exchange (ETDEWEB)

Sugino, Noriko [Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Miura, Yasuo, E-mail: ym58f5@kuhp.kyoto-u.ac.jp [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Yao, Hisayuki [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Iwasa, Masaki; Fujishiro, Aya [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Division of Gastroenterology and Hematology, Shiga University of Medical Science, Shiga 520-2192 (Japan); Fujii, Sumie [Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Hirai, Hideyo [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Takaori-Kondo, Akifumi [Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Ichinohe, Tatsuo [Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Maekawa, Taira [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan)

2016-01-22

Bone marrow (BM) microenvironment has a crucial role in supporting hematopoiesis. Here, by using a microarray analysis, we demonstrate that human BM mesenchymal stromal/stem cells (MSCs) in an early osteoinductive stage (e-MSCs) are characterized by unique hematopoiesis-associated gene expression with an enhanced hematopoiesis-supportive ability. In comparison to BM-MSCs without osteoinductive treatment, gene expression in e-MSCs was significantly altered in terms of their cell adhesion- and chemotaxis-related profiles, as identified with Gene Ontology and Gene Set Enrichment Analysis. Noteworthy, expression of the hematopoiesis-associated molecules CXCL12 and vascular cell adhesion molecule 1 was remarkably decreased in e-MSCs. e-MSCs supported an enhanced expansion of CD34{sup +} hematopoietic stem and progenitor cells, and generation of myeloid lineage cells in vitro. In addition, short-term osteoinductive treatment favored in vivo hematopoietic recovery in lethally irradiated mice that underwent BM transplantation. e-MSCs exhibited the absence of decreased stemness-associated gene expression, increased osteogenesis-associated gene expression, and apparent mineralization, thus maintaining the ability to differentiate into adipogenic cells. Our findings demonstrate the unique biological characteristics of e-MSCs as hematopoiesis-regulatory stromal cells at differentiation stage between MSCs and osteoprogenitor cells and have significant implications in developing new strategy for using pharmacological osteoinductive treatment to support hematopoiesis in hematopoietic stem and progenitor cell transplantation. - Highlights: • Human BM-MSCs in an early osteoinductive stage (e-MSCs) support hematopoiesis. • Adhesion- and chemotaxis-associated gene signatures are altered in e-MSCs. • Expression of CXCL12 and VCAM1 is remarkably decreased in e-MSCs. • e-MSCs are at differentiation stage between MSCs and osteoprogenitor cells. • Osteoinductive treatment

Akirin1 (Mighty), a novel promyogenic factor regulates muscle regeneration and cell chemotaxis

Energy Technology Data Exchange (ETDEWEB)

Salerno, Monica Senna; Dyer, Kelly; Bracegirdle, Jeremy; Platt, Leanne; Thomas, Mark; Siriett, Victoria [Functional Muscle Genomics, AgResearch, Hamilton (New Zealand); Kambadur, Ravi [Functional Muscle Genomics, AgResearch, Hamilton (New Zealand); School of Biological Sciences, Nanyang Technological University, Singapore (Singapore); Sharma, Mridula, E-mail: bchmridu@nus.edu.sg [Functional Muscle Genomics, AgResearch, Hamilton (New Zealand)

2009-07-15

Akirin1 (Mighty) is a downstream target gene of myostatin and has been shown to be a promyogenic factor. Although expressed in many tissues, akirin1 is negatively regulated by myostatin specifically in skeletal muscle tissue. In this manuscript we have characterized the possible function of akirin1 in postnatal muscle growth. Molecular and immunohistological analyses indicated that while low levels of akirin1 are associated with quiescent satellite cells (SC), higher levels of akirin1 are detected in activated proliferating SC indicating that akirin1 could be associated with satellite cell activation. In addition to SC, macrophages also express akirin1, and increased expression of akirin1 resulted in more efficient chemotaxis of both macrophages and myoblasts. Akirin1 appears to regulate chemotaxis of both macrophages and myoblasts by reorganising actin cytoskeleton, leading to more efficient lamellipodia formation via a PI3 kinase dependent pathway. Expression analysis during muscle regeneration also indicated that akirin1 expression is detected very early (day 2) in regenerating muscle, and expression gradually peaks to coincide the nascent myotube formation stage of muscle regeneration. Based on these results we propose that akirin1 could be acting as a transducer of early signals of muscle regeneration. Thus, we speculate that myostatin regulates key steps of muscle regeneration including chemotaxis of inflammatory cells, SC activation and migration through akirin1.

Akirin1 (Mighty), a novel promyogenic factor regulates muscle regeneration and cell chemotaxis

International Nuclear Information System (INIS)

Salerno, Monica Senna; Dyer, Kelly; Bracegirdle, Jeremy; Platt, Leanne; Thomas, Mark; Siriett, Victoria; Kambadur, Ravi; Sharma, Mridula

2009-01-01

Akirin1 (Mighty) is a downstream target gene of myostatin and has been shown to be a promyogenic factor. Although expressed in many tissues, akirin1 is negatively regulated by myostatin specifically in skeletal muscle tissue. In this manuscript we have characterized the possible function of akirin1 in postnatal muscle growth. Molecular and immunohistological analyses indicated that while low levels of akirin1 are associated with quiescent satellite cells (SC), higher levels of akirin1 are detected in activated proliferating SC indicating that akirin1 could be associated with satellite cell activation. In addition to SC, macrophages also express akirin1, and increased expression of akirin1 resulted in more efficient chemotaxis of both macrophages and myoblasts. Akirin1 appears to regulate chemotaxis of both macrophages and myoblasts by reorganising actin cytoskeleton, leading to more efficient lamellipodia formation via a PI3 kinase dependent pathway. Expression analysis during muscle regeneration also indicated that akirin1 expression is detected very early (day 2) in regenerating muscle, and expression gradually peaks to coincide the nascent myotube formation stage of muscle regeneration. Based on these results we propose that akirin1 could be acting as a transducer of early signals of muscle regeneration. Thus, we speculate that myostatin regulates key steps of muscle regeneration including chemotaxis of inflammatory cells, SC activation and migration through akirin1.

Travelling Waves in Hybrid Chemotaxis Models

KAUST Repository

Franz, Benjamin

2013-12-18

Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant), which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybrid models shows good agreement in the case of weak chemotaxis and qualitative agreement for the strong chemotaxis case. In the case of slow cell adaptation, we detect oscillating behaviour of the wave, which cannot be explained by mean-field approximations. © 2013 Society for Mathematical Biology.

Insulin regulates multiple signaling pathways leading to monocyte/macrophage chemotaxis into the wound tissue

Directory of Open Access Journals (Sweden)

Yan Liu

2018-01-01

Full Text Available Wound healing is a complex process that involves sequential phases that overlap in time and space and affect each other dynamically at the gene and protein levels. We previously showed that insulin accelerates wound healing by stimulating faster and regenerative healing. One of the processes that insulin stimulates is an increase in monocyte/macrophage chemotaxis. In this study, we performed experiments in vivo and in vitro to elucidate the signaling transduction pathways that are involved in insulin-induced monocyte/macrophage chemotaxis. We found that insulin stimulates THP-1 cell chemotaxis in a dose-dependent and insulin receptor-dependent manner. We also show that the kinases PI3K-Akt, SPAK/JNK, and p38 MAPK are key molecules in the insulin-induced signaling pathways that lead to chemoattraction of the THP-1 cell. Furthermore, both PI3K-Akt and SPAK/JNK signaling involve Rac1 activation, an important molecule in regulating cell motility. Indeed, topical application of Rac1 inhibitor at an early stage during the healing process caused delayed and impaired healing even in the presence of insulin. These results delineate cell and molecular mechanisms involved in insulin-induced chemotaxis of monocyte/macrophage, cells that are critical for proper healing.

Campylobacter jejuni transducer like proteins: Chemotaxis and beyond.

Science.gov (United States)

Chandrashekhar, Kshipra; Kassem, Issmat I; Rajashekara, Gireesh

2017-07-04

Chemotaxis, a process that mediates directional motility toward or away from chemical stimuli (chemoeffectors/ligands that can be attractants or repellents) in the environment, plays an important role in the adaptation of Campylobacter jejuni to disparate niches. The chemotaxis system consists of core signal transduction proteins and methyl-accepting-domain-containing Transducer like proteins (Tlps). Ligands binding to Tlps relay a signal to chemotaxis proteins in the cytoplasm which initiate a signal transduction cascade, culminating into a directional flagellar movement. Tlps facilitate substrate-specific chemotaxis in C. jejuni, which plays an important role in the pathogen's adaptation, pathobiology and colonization of the chicken gastrointestinal tract. However, the role of Tlps in C. jejuni's host tissue specific colonization, physiology and virulence remains not completely understood. Based on recent studies, it can be predicted that Tlps might be important targets for developing strategies to control C. jejuni via vaccines and antimicrobials.

Effect of a 2.45-GHz radiofrequency electromagnetic field on neutrophil chemotaxis and phagocytosis in differentiated human HL-60 cells.

Science.gov (United States)

Koyama, Shin; Narita, Eijiro; Suzuki, Yoshihisa; Taki, Masao; Shinohara, Naoki; Miyakoshi, Junji

2015-01-01

The potential public health risks of radiofrequency (RF) fields have been discussed at length, especially with the use of mobile phones spreading extensively throughout the world. In order to investigate the properties of RF fields, we examined the effect of 2.45-GHz RF fields at the specific absorption rate (SAR) of 2 and 10 W/kg for 4 and 24 h on neutrophil chemotaxis and phagocytosis in differentiated human HL-60 cells. Neutrophil chemotaxis was not affected by RF-field exposure, and subsequent phagocytosis was not affected either compared with that under sham exposure conditions. These studies demonstrated an initial immune response in the human body exposed to 2.45-GHz RF fields at the SAR of 2 W/kg, which is the maximum value recommended by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) guidelines. The results of our experiments for RF-field exposure at an SAR under 10 W/kg showed very little or no effects on either chemotaxis or phagocytosis in neutrophil-like human HL-60 cells. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

A real time chemotaxis assay unveils unique migratory profiles amongst different primary murine macrophages.

Directory of Open Access Journals (Sweden)

Asif J Iqbal

Full Text Available Chemotaxis assays are an invaluable tool for studying the biological activity of inflammatory mediators such as CC chemokines, which have been implicated in a wide range of chronic inflammatory diseases. Conventional chemotaxis systems such as the modified Boyden chamber are limited in terms of the data captured given that the assays are analysed at a single time-point. We report the optimisation and validation of a label-free, real-time cell migration assay based on electrical cell impedance to measure chemotaxis of different primary murine macrophage populations in response to a range of CC chemokines and other chemoattractant signalling molecules. We clearly demonstrate key differences in the migratory behavior of different murine macrophage populations and show that this dynamic system measures true macrophage chemotaxis rather than chemokinesis or fugetaxis. We highlight an absolute requirement for Gαi signaling and actin cytoskeletal rearrangement as demonstrated by Pertussis toxin and cytochalasin D inhibition. We also studied the chemotaxis of CD14(+ human monocytes and demonstrate distinct chemotactic profiles amongst different monocyte donors to CCL2. This real-time chemotaxis assay will allow a detailed analysis of factors that regulate macrophage responses to chemoattractant cytokines and inflammatory mediators.

A Real Time Chemotaxis Assay Unveils Unique Migratory Profiles amongst Different Primary Murine Macrophages

Science.gov (United States)

Iqbal, Asif J.; Regan-Komito, Daniel; Christou, Ivy; White, Gemma E.; McNeill, Eileen; Kenyon, Amy; Taylor, Lewis; Kapellos, Theodore S.; Fisher, Edward A.; Channon, Keith M.; Greaves, David R.

2013-01-01

Chemotaxis assays are an invaluable tool for studying the biological activity of inflammatory mediators such as CC chemokines, which have been implicated in a wide range of chronic inflammatory diseases. Conventional chemotaxis systems such as the modified Boyden chamber are limited in terms of the data captured given that the assays are analysed at a single time-point. We report the optimisation and validation of a label-free, real-time cell migration assay based on electrical cell impedance to measure chemotaxis of different primary murine macrophage populations in response to a range of CC chemokines and other chemoattractant signalling molecules. We clearly demonstrate key differences in the migratory behavior of different murine macrophage populations and show that this dynamic system measures true macrophage chemotaxis rather than chemokinesis or fugetaxis. We highlight an absolute requirement for Gαi signaling and actin cytoskeletal rearrangement as demonstrated by Pertussis toxin and cytochalasin D inhibition. We also studied the chemotaxis of CD14+ human monocytes and demonstrate distinct chemotactic profiles amongst different monocyte donors to CCL2. This real-time chemotaxis assay will allow a detailed analysis of factors that regulate macrophage responses to chemoattractant cytokines and inflammatory mediators. PMID:23516549

The Vi capsular polysaccharide enables Salmonella enterica serovar typhi to evade microbe-guided neutrophil chemotaxis.

Directory of Open Access Journals (Sweden)

Tamding Wangdi

2014-08-01

Full Text Available Salmonella enterica serovar Typhi (S. Typhi causes typhoid fever, a disseminated infection, while the closely related pathogen S. enterica serovar Typhimurium (S. Typhimurium is associated with a localized gastroenteritis in humans. Here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. Surprisingly, neutrophils extended chemotactic pseudopodia toward Escherichia coli and S. Typhimurium, but not toward S. Typhi. Bacterial-guided chemotaxis was dependent on the presence of complement component 5a (C5a and C5a receptor (C5aR. Deletion of S. Typhi capsule biosynthesis genes markedly enhanced the chemotactic response of neutrophils in vitro. Furthermore, deletion of capsule biosynthesis genes heightened the association of S. Typhi with neutrophils in vivo through a C5aR-dependent mechanism. Collectively, these data suggest that expression of the virulence-associated (Vi capsular polysaccharide of S. Typhi obstructs bacterial-guided neutrophil chemotaxis.

A Sensitive Chemotaxis Assay Using a Novel Microfluidic Device

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Chen Zhang

2013-01-01

Full Text Available Existing chemotaxis assays do not generate stable chemotactic gradients and thus—over time—functionally measure only nonspecific random motion (chemokinesis. In comparison, microfluidic technology has the capacity to generate a tightly controlled microenvironment that can be stably maintained for extended periods of time and is, therefore, amenable to adaptation for assaying chemotaxis. We describe here a novel microfluidic device for sensitive assay of cellular migration and show its application for evaluating the chemotaxis of smooth muscle cells in a chemokine gradient.

Quantitative analysis of eosinophil chemotaxis tracked using a novel optical device -- TAXIScan.

Science.gov (United States)

Nitta, Nao; Tsuchiya, Tomoko; Yamauchi, Akira; Tamatani, Takuya; Kanegasaki, Shiro

2007-03-30

We have reported previously the development of an optically accessible, horizontal chemotaxis apparatus, in which migration of cells in the channel from a start line can be traced with time-lapse intervals using a CCD camera (JIM 282, 1-11, 2003). To obtain statistical data of migrating cells, we have developed quantitative methods to calculate various parameters in the process of chemotaxis, employing human eosinophil and CXCL12 as a model cell and a model chemoattractant, respectively. Median values of velocity and directionality of each cell within an experimental period could be calculated from the migratory pathway data obtained from time-lapse images and the data were expressed as Velocity-Directionality (VD) plot. This plot is useful for quantitatively analyzing multiple migrating cells exposed to a certain chemoattractant, and can distinguish chemotaxis from random migration. Moreover precise observation of cell migration revealed that each cell had a different lag period before starting chemotaxis, indicating variation in cell sensitivity to the chemoattractant. Thus lag time of each cell before migration, and time course of increment of the migrating cell ratio at the early stages could be calculated. We also graphed decrement of still moving cell ratio at the later stages by calculating the duration time of cell migration of each cell. These graphs could distinguish different motion patterns of chemotaxis of eosinophils, in response to a range of chemoattractants; PGD(2), fMLP, CCL3, CCL5 and CXCL12. Finally, we compared parameters of eosinophils from normal volunteers, allergy patients and asthma patients and found significant difference in response to PGD(2). The quantitative methods described here could be applicable to image data obtained with any combination of cells and chemoattractants and useful not only for basic studies of chemotaxis but also for diagnosis and for drug screening.

Azospirillum brasilense Chemotaxis Depends on Two Signaling Pathways Regulating Distinct Motility Parameters.

Science.gov (United States)

Mukherjee, Tanmoy; Kumar, Dhivya; Burriss, Nathan; Xie, Zhihong; Alexandre, Gladys

2016-06-15

The genomes of most motile bacteria encode two or more chemotaxis (Che) systems, but their functions have been characterized in only a few model systems. Azospirillum brasilense is a motile soil alphaproteobacterium able to colonize the rhizosphere of cereals. In response to an attractant, motile A. brasilense cells transiently increase swimming speed and suppress reversals. The Che1 chemotaxis pathway was previously shown to regulate changes in the swimming speed, but it has a minor role in chemotaxis and root surface colonization. Here, we show that a second chemotaxis system, named Che4, regulates the probability of swimming reversals and is the major signaling pathway for chemotaxis and wheat root surface colonization. Experimental evidence indicates that Che1 and Che4 are functionally linked to coordinate changes in the swimming motility pattern in response to attractants. The effect of Che1 on swimming speed is shown to enhance the aerotactic response of A. brasilense in gradients, likely providing the cells with a competitive advantage in the rhizosphere. Together, the results illustrate a novel mechanism by which motile bacteria utilize two chemotaxis pathways regulating distinct motility parameters to alter movement in gradients and enhance the chemotactic advantage. Chemotaxis provides motile bacteria with a competitive advantage in the colonization of diverse niches and is a function enriched in rhizosphere bacterial communities, with most species possessing at least two chemotaxis systems. Here, we identify the mechanism by which cells may derive a significant chemotactic advantage using two chemotaxis pathways that ultimately regulate distinct motility parameters. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Simulation of Paramecium Chemotaxis Exposed to Calcium Gradients.

Science.gov (United States)

Sarvestani, Ali N; Shamloo, Amir; Ahmadian, Mohammad Taghi

2016-06-01

Paramecium or other ciliates have the potential to be utilized for minimally invasive surgery systems, making internal body organs accessible. Paramecium shows interesting responses to changes in the concentration of specific ions such as K(+), Mg(2+), and Ca(2+) in the ambient fluid. Some specific responses are observed as, changes in beat pattern of cilia and swimming toward or apart from the ion source. Therefore developing a model for chemotactic motility of small organisms is necessary in order to control the directional movements of these microorganisms before testing them. In this article, we have developed a numerical model, investigating the effects of Ca(2+) on swimming trajectory of Paramecium. Results for Ca(2+)-dependent chemotactic motility show that calcium gradients are efficient actuators for controlling the Paramecium swimming trajectory. After applying a very low Ca(2+) gradient, a directional chemotaxis of swimming Paramecium is observable in this model. As a result, chemotaxis is shown to be an efficient method for controlling the propulsion of these small organisms.

Coronin 1B regulates S1P-induced human lung endothelial cell chemotaxis: role of PLD2, protein kinase C and Rac1 signal transduction.

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Peter V Usatyuk

Full Text Available Coronins are a highly conserved family of actin binding proteins that regulate actin-dependent processes such as cell motility and endocytosis. We found that treatment of human pulmonary artery endothelial cells (HPAECs with the bioactive lipid, sphingosine-1-phosphate (S1P rapidly stimulates coronin 1B translocation to lamellipodia at the cell leading edge, which is required for S1P-induced chemotaxis. Further, S1P-induced chemotaxis of HPAECs was attenuated by pretreatment with small interfering RNA (siRNA targeting coronin 1B (∼36%, PLD2 (∼45% or Rac1 (∼50% compared to scrambled siRNA controls. Down regulation PLD2 expression by siRNA also attenuated S1P-induced coronin 1B translocation to the leading edge of the cell periphery while PLD1 silencing had no effect. Also, S1P-induced coronin 1B redistribution to cell periphery and chemotaxis was attenuated by inhibition of Rac1 and over-expression of dominant negative PKC δ, ε and ζ isoforms in HPAECs. These results demonstrate that S1P activation of PLD2, PKC and Rac1 is part of the signaling cascade that regulates coronin 1B translocation to the cell periphery and the ensuing cell chemotaxis.

Compound C inhibits macrophage chemotaxis through an AMPK-independent mechanism

Energy Technology Data Exchange (ETDEWEB)

Lee, Youngyi [College of Pharmacy, Woosuk University, Wanju, Jeonbuk 55338 (Korea, Republic of); Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Jeonbuk 54896 (Korea, Republic of); Park, Byung-Hyun, E-mail: bhpark@jbnu.ac.kr [Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Jeonbuk 54896 (Korea, Republic of); Bae, Eun Ju, E-mail: ejbae@woosuk.ac.kr [College of Pharmacy, Woosuk University, Wanju, Jeonbuk 55338 (Korea, Republic of)

2016-01-15

Macrophage infiltration in adipose tissue is a well-established cause of obesity-linked insulin resistance. AMP-activated protein kinase (AMPK) activation in peripheral tissues such as adipose tissue has beneficial effects on the protection against obesity-induced insulin resistance, which is mainly mediated by prevention of adipose tissue macrophage infiltration and inflammation. In examining the role of AMPK on adipose tissue inflammation, we unexpectedly found that compound C (CC), despite its inhibition of AMPK, robustly inhibited macrophage chemotaxis in RAW 264.7 cells when adipocyte conditioned medium (CM) was used as a chemoattractant. Here, we report that CC inhibition of macrophage migration occurred independently of AMPK. Mechanistically, this inhibitory effect of cell migration by CC was mediated by inhibition of the focal adhesion kinase, AKT, nuclear factor κB pathways. Moreover, the expression of chemokine monocyte chemoattractant protein-1 and pro-inflammatory genes such as tumor necrosis factor α and inducible nitric oxide synthase were prevented by CC treatment in RAW 264.7 cells stimulated with either adipocyte CM or lipopolysaccharide. Lastly, in accord with the findings of the anti-inflammatory effect of CC, we demonstrated that CC functioned as a repressor of macrophage CM-mediated insulin resistance in adipocytes. Taken together, our results suggest that CC serves as a useful inhibitory molecule against macrophage chemotaxis into adipose tissue and thus might have therapeutic potential for the treatment of obesity-linked adipose inflammation. - Highlights: • Compound C (CC) inhibits macrophage chemotaxis regardless of AMPK suppression. • CC enhances insulin sensitivity in adipocytes. • CC inhibits focal adhesion kinase, AKT, and NF-κB signaling in RAW 264.7 cells.

Relevance of intracellular polarity to accuracy of eukaryotic chemotaxis

International Nuclear Information System (INIS)

Hiraiwa, Tetsuya; Nishikawa, Masatoshi; Shibata, Tatsuo; Nagamatsu, Akihiro; Akuzawa, Naohiro

2014-01-01

Eukaryotic chemotaxis is usually mediated by intracellular signals that tend to localize at the front or back of the cell. Such intracellular polarities frequently require no extracellular guidance cues, indicating that spontaneous polarization occurs in the signal network. Spontaneous polarization activity is considered relevant to the persistent motions in random cell migrations and chemotaxis. In this study, we propose a theoretical model that connects spontaneous intracellular polarity and motile ability in a chemoattractant solution. We demonstrate that the intracellular polarity can enhance the accuracy of chemotaxis. Chemotactic accuracy should also depend on chemoattractant concentration through the concentration-dependent correlation time in the polarity direction. Both the polarity correlation time and the chemotactic accuracy depend on the degree of responsiveness to the chemical gradient. We show that optimally accurate chemotaxis occurs at an intermediate responsiveness of intracellular polarity. Experimentally, we find that the persistence time of randomly migrating Dictyostelium cells depends on the chemoattractant concentration, as predicted by our theory. At the optimum responsiveness, this ameboid cell can enhance its chemotactic accuracy tenfold. (paper)

COUPLED CHEMOTAXIS FLUID MODEL

KAUST Repository

LORZ, ALEXANDER

2010-06-01

We consider a model system for the collective behavior of oxygen-driven swimming bacteria in an aquatic fluid. In certain parameter regimes, such suspensions of bacteria feature large-scale convection patterns as a result of the hydrodynamic interaction between bacteria. The presented model consist of a parabolicparabolic chemotaxis system for the oxygen concentration and the bacteria density coupled to an incompressible Stokes equation for the fluid driven by a gravitational force of the heavier bacteria. We show local existence of weak solutions in a bounded domain in d, d = 2, 3 with no-flux boundary condition and in 2 in the case of inhomogeneous Dirichlet conditions for the oxygen. © 2010 World Scientific Publishing Company.

Chemotaxis toward carbohydrates and peptides by mixed ruminal protozoa when fed, fasted, or incubated with polyunsaturated fatty acids.

Science.gov (United States)

Diaz, H L; Karnati, S K R; Lyons, M A; Dehority, B A; Firkins, J L

2014-01-01

In contrast to the well-characterized chemotaxis and migratory behavior between the dorsal and ventral locations of the rumen by isotrichids, we hypothesized that chemotaxis toward soluble nutrients maintains entodiniomorphid protozoa in the particulate fraction. The objectives of these experiments were to compare the dose-responsive chemotaxis (1) toward different glucose concentrations when ruminal samples were harvested from fed versus fasted cows; (2) toward increasing concentrations of glucose compared with xylose when protozoa were harvested from a fed cow; (3) toward peptides of bacterial, protozoal, and soy origin; and (4) toward glucose when mixed ruminal protozoa were previously incubated for 0, 3, or 6h in the presence of emulsified polyunsaturated fatty acids (PUFA; Liposyn II, Hospira, Lake Forest, IL). In experiment 1, isotrichid protozoa decreased chemotaxis toward increasing glucose concentration when cows were fasted. Entodiniomorphids exhibited chemotaxis to similar concentrations of glucose as did isotrichids, but to a lesser magnitude of response. In experiment 2, xylose was chemotactic to both groups. Xylose might draw fibrolytic entodiniomorphid protozoa toward newly ingested feed. In contrast, even though isotrichids should not use xylose as an energy source, they were highly chemoattracted to xylose. In experiment 3, entodiniomorphids were not selectively chemoattracted toward bacterial or protozoal peptides compared with soy peptides. In experiment 4, despite isotrichid populations decreasing in abundance with increasing time of incubation in PUFA, chemotaxis to glucose remained unchanged. In contrast, entodiniomorphids recovered chemotaxis to glucose with increased time of PUFA incubation. Current results support isotrichid chemotaxis to sugars but also our hypothesis that a more moderate chemotaxis toward glucose and peptides explains how they swim in the fluid but pass from the rumen with the potentially digestible fraction of

Chemotaxis on the Move – Active Learning Teaching Tool

Directory of Open Access Journals (Sweden)

Ann H. Williams

2010-11-01

Full Text Available In Microbiology courses, concepts such as chemotaxis can be difficult to visualize for students. Described here is a short visual playacting activity where students simulate E.coli moving towards an attractant source using a biased random walk. This short interactive activity is performed in the lecture course of General Microbiology that contains mostly Biology major juniors or seniors prior to the lecture on the subject of chemotaxis and flagellar movements. It is utilized to help students (class of 30–40 understand and visualize the process of chemotaxis and the concepts of random walk, biased random walk, runs, tumbles and directed movement of flagella in response to attractants and repellents.

Feedback control architecture and the bacterial chemotaxis network.

Directory of Open Access Journals (Sweden)

Abdullah Hamadeh

2011-05-01

Full Text Available Bacteria move towards favourable and away from toxic environments by changing their swimming pattern. This response is regulated by the chemotaxis signalling pathway, which has an important feature: it uses feedback to 'reset' (adapt the bacterial sensing ability, which allows the bacteria to sense a range of background environmental changes. The role of this feedback has been studied extensively in the simple chemotaxis pathway of Escherichia coli. However it has been recently found that the majority of bacteria have multiple chemotaxis homologues of the E. coli proteins, resulting in more complex pathways. In this paper we investigate the configuration and role of feedback in Rhodobacter sphaeroides, a bacterium containing multiple homologues of the chemotaxis proteins found in E. coli. Multiple proteins could produce different possible feedback configurations, each having different chemotactic performance qualities and levels of robustness to variations and uncertainties in biological parameters and to intracellular noise. We develop four models corresponding to different feedback configurations. Using a series of carefully designed experiments we discriminate between these models and invalidate three of them. When these models are examined in terms of robustness to noise and parametric uncertainties, we find that the non-invalidated model is superior to the others. Moreover, it has a 'cascade control' feedback architecture which is used extensively in engineering to improve system performance, including robustness. Given that the majority of bacteria are known to have multiple chemotaxis pathways, in this paper we show that some feedback architectures allow them to have better performance than others. In particular, cascade control may be an important feature in achieving robust functionality in more complex signalling pathways and in improving their performance.

Highlighting the role of Ras and Rap during Dictyostelium chemotaxis

NARCIS (Netherlands)

Kortholt, Arjan; van Haastert, Peter J. M.

Chemotaxis, the directional movement towards a chemical compound, is an essential property of many cells and has been linked to the development and progression of many diseases. Eukaryotic chemotaxis is a complex process involving gradient sensing, cell polarity, remodelling of the cytoskeleton and

DMPD: Cellular signaling in macrophage migration and chemotaxis. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 11073096 Cellular signaling in macrophage migration and chemotaxis. Jones GE. J Leu...koc Biol. 2000 Nov;68(5):593-602. (.png) (.svg) (.html) (.csml) Show Cellular signaling in macrophage migration... and chemotaxis. PubmedID 11073096 Title Cellular signaling in macrophage migration and chemotaxis. Autho

CXCL1 is a negative regulator of mast cell chemotaxis to airway smooth muscle cell products in vitro.

Science.gov (United States)

Alkhouri, H; Moir, L M; Armour, C L; Hughes, J M

2014-03-01

Activated mast cells (MC) numbers on airway smooth muscle (ASM) are increased in eosinophilic asthma. In vitro, asthmatic cytokine-stimulated ASM cell-conditioned medium (CM) induces more MC chemotaxis than CM from nonasthmatic ASM cells. Intriguingly the nonasthmatic ASM CM inhibits MC chemotaxis to the asthmatic ASM CM. However, the inhibitory factor(s) in the nonasthmatic ASM CM is still to be identified. To identify the factor(s) released by nonasthmatic ASM cells that inhibits MC chemotaxis. Confluent, serum-starved ASM cells from donors with and without asthma were stimulated with IL-1β and T-helper (Th)1 (TNFα and IFNγ) or Th2 (IL-4, IL-13) cytokines, or left unstimulated. CM samples were collected after 24 h, and a potential inhibitory factor identified using cytokine protein arrays. Its production was assessed using ELISA and RT-PCR and inhibitory role investigated in MC chemotaxis and Ca(2+) mobilization assays. Only CXCL1 was produced in greater amounts by nonasthmatic than asthmatic ASM cells following Th1 and Th2 cytokine stimulation. CXCL1 mRNA expression was also increased. Exogenous rh-CXCL1 significantly inhibited MC intracellular Ca(2+) mobilization and chemotaxis to either CXCL10, CXCL8 or CM collected from asthmatic ASM cells following Th1 or Th2 cytokine stimulation. Neutralizing CXCL1 in nonasthmatic ASM CM or blocking its receptor significantly promoted MC chemotaxis. CXCL1 was a major factor regulating MC chemotaxis in vitro. Its differential release by ASM cells may explain the differences observed in MC localization to the ASM of people with and without asthma. CXCL1 inhibition of MC recruitment to the ASM may lead to new targets to limit asthma pathophysiology. © 2013 John Wiley & Sons Ltd.

Seeding-inspired chemotaxis genetic algorithm for the inference of biological systems.

Science.gov (United States)

Wu, Shinq-Jen; Wu, Cheng-Tao

2014-09-18

A large challenge in the post-genomic era is to obtain the quantitatively dynamic interactive information of the important constitutes of underlying systems. The S-system is a dynamic and structurally rich model that determines the net strength of interactions between genes and/or proteins. Good generation characteristics without the need for prior information have allowed S-systems to become one of the most promising canonical models. Various evolutionary computation technologies have recently been developed for the identification of system parameters and skeletal-network structures. However, the gaps between the truncated and preserved terms remain too small. Additionally, current research methods fail to identify the structures of high dimensional systems (e.g., 30 genes with 1800 connections). Optimization technologies should converge fast and have the ability to adaptively adjust the search. In this study, we propose a seeding-inspired chemotaxis genetic algorithm (SCGA) that can force evolution to adjust the population movement to identify a favorable location. The seeding-inspired training strategy is a method to achieve optimal results with limited resources. SCGA introduces seeding-inspired genetic operations to allow a population to possess competitive power (exploitation and exploration) and a winner-chemotaxis-induced population migration to force a population to repeatedly tumble away from an attractor and swim toward another attractor. SCGA was tested on several canonical biological systems. SCGA not only learned the correct structure within only one to three pruning steps but also ensures pruning safety. The values of the truncated terms were all smaller than 10 -14 , even for a thirty-gene system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Drosophila chemotaxis: a first look with neurogenetics.

Science.gov (United States)

Gao, Xiaojing J

2014-01-01

Chemotaxis, the ability to direct movements according to chemical cues in the environment, is important for the survival of most organisms. In our original article, we combined a quantitative behavioral assay with genetic manipulations to dissect the neural substrate for chemotaxis. In this Extra View article, we offer a more chronological narration of the findings leading to our key conclusion that aversion engages specific motor-related circuits and kinematics. We speculate on the separation and crosstalk between aversion and attraction circuits in the brain and the ventral nerve cord, and the implication for valence encoding in the olfactory system.

Eotaxin induces degranulation and chemotaxis of eosinophils through the activation of ERK2 and p38 mitogen-activated protein kinases

DEFF Research Database (Denmark)

Kampen, G T; Stafford, S; Adachi, T

2000-01-01

Eotaxin and other CC chemokines acting via CC chemokine receptor-3 (CCR3) are believed to play an integral role in the development of eosinophilic inflammation in asthma and allergic inflammatory diseases. However, little is known about the intracellular events following agonist binding to CCR3...... and the relationship of these events to the functional response of the cell. The objectives of this study were to investigate CCR3-mediated activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase-2 (ERK2), p38, and c-jun N-terminal kinase (JNK) in eosinophils and to assess...... the requirement for MAP kinases in eotaxin-induced eosinophil cationic protein (ECP) release and chemotaxis. MAP kinase activation was studied in eotaxin-stimulated eosinophils (more than 97% purity) by Western blotting and immune-complex kinase assays. ECP release was measured by radioimmunoassay. Chemotaxis...

Signal transduction and chemotaxis in mast cells

Czech Academy of Sciences Publication Activity Database

Dráber, Petr; Hálová, Ivana; Polakovičová, Iva; Kawakami, T.

2016-01-01

Roč. 778, jaro (2016), s. 11-23 ISSN 0014-2999 R&D Projects: GA ČR(CZ) GA14-09807S; GA ČR(CZ) GBP302/12/G101; GA ČR(CZ) GA14-00703S Institutional support: RVO:68378050 Keywords : Mast cell * IgE receptor * KIT receptor * Signal transduction * Chemotaxis * Plasma membrane Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.896, year: 2016

The control of neutrophil chemotaxis by inhibitors of cathepsin G and chymotrypsin.

Science.gov (United States)

Lomas, D A; Stone, S R; Llewellyn-Jones, C; Keogan, M T; Wang, Z M; Rubin, H; Carrell, R W; Stockley, R A

1995-10-06

Neutrophil chemotaxis plays an important role in the inflammatory response and when excessive or persistent may augment tissue damage. The effects of inhibitors indicated the involvement of one or more serine proteinases in human neutrophil migration and shape change in response to a chemoattractant. Monospecific antibodies, chloromethylketone inhibitors, and reactive-site mutants of alpha 1-antitrypsin and alpha 1-antichymotrypsin were used to probe the specificity of the proteinases involved in chemotaxis. Antibodies specific for cathepsin G inhibited chemotaxis. Moreover, rapid inhibitors of cathepsin G and alpha-chymotrypsin suppressed neutrophil chemotaxis to the chemoattractants N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) and zymosan-activated serum in multiple blind well assays and to fMLP in migration assays under agarose. The concentrations of antichymotrypsin mutants that reduced chemotaxis by 50% would inactivate free cathepsin G with a half-life of 1.5-3 s, whereas the concentrations of chloromethylketones required to produce a similar inhibition of chemotaxis would inactivate cathepsin G with a half-life of 345 s. These data suggest different modes of action for these two classes of inhibitors. Indeed the chloromethylketone inhibitors of cathepsin G (Z-Gly-Leu-Phe-CMK) and to a lesser extent of chymotrypsin (Cbz-Gly-Gly-Phe-CMK) mediated their effect by preventing a shape change in the purified neutrophils exposed to fMLP. Antichymotrypsin did not affect shape change in response to fMLP even at concentrations that were able to reduce neutrophil chemotaxis by 50%. These results support the involvement of cell surface proteinases in the control of cell migration and show that antichymotrypsin and chloromethylketones have differing modes of action. This opens the possibility for the rational design of anti-inflammatory agents targeted at neutrophil membrane enzymes.

The Impact of Odor--Reward Memory on Chemotaxis in Larval "Drosophila"

Science.gov (United States)

Schleyer, Michael; Reid, Samuel F.; Pamir, Evren; Saumweber, Timo; Paisios, Emmanouil; Davies, Alexander; Gerber, Bertram; Louis, Matthieu

2015-01-01

How do animals adaptively integrate innate with learned behavioral tendencies? We tackle this question using chemotaxis as a paradigm. Chemotaxis in the "Drosophila" larva largely results from a sequence of runs and oriented turns. Thus, the larvae minimally need to determine (i) how fast to run, (ii) when to initiate a turn, and (iii)…

Normal chemotaxis in Dictyostelium discoideum cells with a depolarized plasma membrane potential

NARCIS (Netherlands)

Duijn, Bert van; Vogelzang, Sake A.; Ypey, Dirk L.; Molen, Loek G. van der; Haastert, Peter J.M. van

1990-01-01

We examined a possible role for the plasma membrane potential in signal transduction during cyclic AMP-induced chemotaxis in the cellular slime mold Dictyostelium discoideum. Chemotaxis, cyclic GMP and cyclic AMP responses in cells with a depolarized membrane potential were measured. Cells can be

Relation between chemotaxis and consumption of amino acids in bacteria

Science.gov (United States)

Yang, Yiling; M. Pollard, Abiola; Höfler, Carolin; Poschet, Gernot; Wirtz, Markus; Hell, Rüdiger

2015-01-01

Summary Chemotaxis enables bacteria to navigate chemical gradients in their environment, accumulating toward high concentrations of attractants and avoiding high concentrations of repellents. Although finding nutrients is likely to be an important function of bacterial chemotaxis, not all characterized attractants are nutrients. Moreover, even for potential nutrients, the exact relation between the metabolic value of chemicals and their efficiency as chemoattractants has not been systematically explored. Here we compare the chemotactic response of amino acids with their use by bacteria for two well‐established models of chemotactic behavior, E scherichia coli and B acillus subtilis. We demonstrate that in E . coli chemotaxis toward amino acids indeed strongly correlates with their utilization. However, no such correlation is observed for B . subtilis, suggesting that in this case, the amino acids are not followed because of their nutritional value but rather as environmental cues. PMID:25807888

A portable chemotaxis platform for short and long term analysis.

Directory of Open Access Journals (Sweden)

Chenjie Xu

Full Text Available Flow-based microfluidic systems have been widely utilized for cell migration studies given their ability to generate versatile and precisely defined chemical gradients and to permit direct visualization of migrating cells. Nonetheless, the general need for bulky peripherals such as mechanical pumps and tubing and the complicated setup procedures significantly limit the widespread use of these microfluidic systems for cell migration studies. Here we present a simple method to power microfluidic devices for chemotaxis assays using the commercially available ALZET® osmotic pumps. Specifically, we developed a standalone chemotaxis platform that has the same footprint as a multiwell plate and can generate well-defined, stable chemical gradients continuously for up to 7 days. Using this platform, we validated the short-term (24 hours and long-term (72 hours concentration dependent PDGF-BB chemotaxis response of human bone marrow derived mesenchymal stem cells.

Different migration patterns of sea urchin and mouse sperm revealed by a microfluidic chemotaxis device.

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Haixin Chang

Full Text Available Chemotaxis refers to a process whereby cells move up or down a chemical gradient. Sperm chemotaxis is known to be a strategy exploited by marine invertebrates such as sea urchins to reach eggs efficiently in moving water. Less is understood about how or whether chemotaxis is used by mammalian sperm to reach eggs, where fertilization takes place within the confinement of a reproductive tract. In this report, we quantitatively assessed sea urchin and mouse sperm chemotaxis using a recently developed microfluidic model and high-speed imaging. Results demonstrated that sea urchin Arbacia punctulata sperm were chemotactic toward the peptide resact with high chemotactic sensitivity, with an average velocity Vx up the chemical gradient as high as 20% of its average speed (238 μm/s, while mouse sperm displayed no statistically significant chemotactic behavior in progesterone gradients, which had been proposed to guide mammalian sperm toward eggs. This work demonstrates the validity of a microfluidic model for quantitative sperm chemotaxis studies, and reveals a biological insight that chemotaxis up a progesterone gradient may not be a universal strategy for mammalian sperm to reach eggs.

Chemotaxis-growth under the influence of lateral inhibition in a three-component reaction–diffusion system

International Nuclear Information System (INIS)

Kawaguchi, Satoshi

2011-01-01

In this study, we consider the effects of chemotaxis and lateral inhibition on an activator in a three-component reaction–diffusion system. Simulation results show that spot, planar and travelling front solutions in two dimensions are destabilized to form multibranch patterns. In order to analyse the stability of stationary solutions, a singular perturbation method is employed. The bifurcation diagrams suggest that chemotaxis and lateral inhibition cooperatively result in the destabilization of the stationary solutions. Our three-component model is compared with the two-component chemotaxis-growth model. Furthermore, the conditions for observing the cooperative effects of chemotaxis and lateral inhibition on an activator in experiments are inferred from the model

Suppression of blood monocyte and neutrophil chemotaxis in acute human malaria

DEFF Research Database (Denmark)

Nielsen, H; Kharazmi, A; Theander, T G

1986-01-01

tested monocyte chemotactic responsiveness in 19 patients with acute primary attack malaria. In addition, the neutrophil chemotaxis was measured in 12 patients. Before the initiation of antimalarial treatment a significant depression of monocyte chemotaxis was observed in approximately half...... of the patients when compared with healthy control subjects. The depression was found in Plasmodium falciparum malaria as well as in P. vivax or P. ovale malaria patients. The defective responsiveness was not receptor specific, since the responses towards casein and zymosan activated serum proved to be equally...... of treatment, and nearly normalized after 7 days (87% of controls). Furthermore, monocyte phagocytic and candidacidal activities were assessed in the same patients on admission and during the follow-up. In contrast to chemotaxis, these functions were normal in all of the patients whenever measured...

Chemotaxis of C. elegans in 3D media: a model for navigation of undulatory microswimmers

Science.gov (United States)

Patel, Amar; Bilbao, Alejandro; Rahman, Mizanur; Vanapalli, Siva; Blawzdziewicz, Jerzy

2017-11-01

While the natural environment of C. elegans consists of complex 3D media (e.g., decomposing organic matter and water), most studies of chemotactic behavior of this nematode are limited to 2D. We present a 3D chemotaxis model that combines a realistic geometrical representation of body movements associated with 3D maneuvers, an analysis of mechanical interactions of the nematode body with the surrounding medium to determine nematode trajectories, and a simple memory-function description of chemosensory apparatus that controls the frequency, magnitude, and timing of turning maneuvers. We show that two main chemotaxis strategies of C. elegans moving in 2D, i.e., the biased random walk and gradual turn, are effective also in 3D, provided that 2D turns are supplemented by the roll maneuvers that enable 3D reorientation. Optimal choices of chemosensing and gait-control parameters are discussed; we show that the nematode can maintain efficient chemotaxis in burrowing and swimming by adjusting the undulation frequency alone, without changing the chemotactic component of the body control. Understanding how C. elegans efficiently navigates in 3D media may help in developing self-navigating artificial microswimmers. Supported by NSF Grant No. CBET 1603627.

Evaluation of polymorphonuclear leukocyte chemotaxis of adult and neonatal rhesus monkeys using 51-chromium labeling method

International Nuclear Information System (INIS)

Kinoshita, Yo; Masuda, Kiyokazu; Kobayashi, Yohnosuke

1987-01-01

Chemotaxis of polymorphonuclear leukocytes (PMN) from heparinized venous blood of 8 adult rhesus monkeys (Macaca Mulatta) and 13 rhesus monkey neonates within 48 hours of birth were evaluated by using 51-chromium labeling method. PMNs were prepared by Ficoll-Hypaque gradient and dextran sedimentation procedures and the final 51-chromium uptake was 3.21 ± 1.27 % to original count. PMN chemotaxis was succeeded by using two different chemotaxis filters (Nuclepore filter on top of Millipore filter) with incubation at 37 deg C for 90 min. The mean value of target: non target ratio (CPM in lower filter with chemoattractant/CPM in lower filter without chemoattractant) of 3.56 ± 2.49 from neonates showed no significant difference from that of 4.44 ± 1.24 from adults. Only about 30 % of neonates showed an impaired chemotaxis, but others showed similar chemotactic activity as adults. The results show that the 51-chromium labeling method is useful to assess neutrophil functions in rhesus monkey species and suggest that host defense mechanism of the rhesus monkey may differ from that of human in neonatal period. (author)

Global Solutions to the Coupled Chemotaxis-Fluid Equations

KAUST Repository

Duan, Renjun

2010-08-10

In this paper, we are concerned with a model arising from biology, which is a coupled system of the chemotaxis equations and the viscous incompressible fluid equations through transport and external forcing. The global existence of solutions to the Cauchy problem is investigated under certain conditions. Precisely, for the Chemotaxis-Navier-Stokes system over three space dimensions, we obtain global existence and rates of convergence on classical solutions near constant states. When the fluid motion is described by the simpler Stokes equations, we prove global existence of weak solutions in two space dimensions for cell density with finite mass, first-order spatial moment and entropy provided that the external forcing is weak or the substrate concentration is small. © Taylor & Francis Group, LLC.

Macrophage migration inhibitory factor triggers chemotaxis of CD74+CXCR2+ NKT cells in chemically induced IFN-γ-mediated skin inflammation.

Science.gov (United States)

Hsieh, Chia-Yuan; Chen, Chia-Ling; Lin, Yee-Shin; Yeh, Trai-Ming; Tsai, Tsung-Ting; Hong, Ming-Yuan; Lin, Chiou-Feng

2014-10-01

IFN-γ mediates chemically induced skin inflammation; however, the mechanism by which IFN-γ-producing cells are recruited to the sites of inflammation remains undefined. Secretion of macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, from damaged cells may promote immune cell recruitment. We hypothesized that MIF triggers an initial step in the chemotaxis of IFN-γ-producing cells in chemically induced skin inflammation. Using acute and chronic models of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mouse ears, MIF expression was examined, and its role in this process was investigated pharmacologically. The cell populations targeted by MIF, their receptor expression patterns, and the effects of MIF on cell migration were examined. TPA directly caused cytotoxicity accompanied by MIF release in mouse ear epidermal keratinocytes, as well as in human keratinocytic HaCaT cells. Treatment with the MIF antagonist (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester considerably attenuated TPA-induced ear swelling, leukocyte infiltration, epidermal cell proliferation, and dermal angiogenesis. Inhibition of MIF greatly diminished the dermal infiltration of IFN-γ(+) NKT cells, whereas the addition of exogenous TPA and MIF to NKT cells promoted their IFN-γ production and migration, respectively. MIF specifically triggered the chemotaxis of NKT cells via CD74 and CXCR2, and the resulting depletion of NKT cells abolished TPA-induced skin inflammation. In TPA-induced skin inflammation, MIF is released from damaged keratinocytes and then triggers the chemotaxis of CD74(+)CXCR2(+) NKT cells for IFN-γ production. Copyright © 2014 by The American Association of Immunologists, Inc.

Chemotaxis of nurse shark leukocytes.

Science.gov (United States)

Obenauf, S D; Smith, S H

1985-01-01

Studies were conducted to determine the ability of leukocytes from the nurse shark to migrate in an in vitro micropore filter chemotaxis assay and to determine optimal assay conditions and suitable attractants for such an assay. A migratory response was seen with several attractants: activated rat serum, activated shark plasma, and a pool of shark complement components. Only the response to activated rat serum was chemotactic, as determined by the checkerboard assay.

Dispatch. Dictyostelium chemotaxis: fascism through the back door?

Science.gov (United States)

Insall, Robert

2003-04-29

Aggregating Dictyostelium cells secrete cyclic AMP to attract their neighbours by chemotaxis. It has now been shown that adenylyl cyclase is enriched in the rear of cells, and this localisation is required for normal aggregation.

Confinement dependent chemotaxis in two-photon polymerized linear migration constructs with highly definable concentration gradients

DEFF Research Database (Denmark)

Hjortø, Gertrud Malene; Olsen, Mark Holm; Svane, Inge Marie

2015-01-01

Dendritic cell chemotaxis is known to follow chemoattractant concentration gradients through tissue of heterogeneous pore sizes, but the dependence of migration velocity on pore size and gradient steepness is not fully understood. We enabled chemotaxis studies for at least 42 hours at confinement...

Exact solutions of certain nonlinear chemotaxis diffusion reaction ...

Indian Academy of Sciences (India)

constructed coupled differential equations. The results obtained ... Nonlinear diffusion reaction equation; chemotaxis; auxiliary equation method; solitary wave solutions. ..... fact limits the scope of applications of the derived results. ... Research Fellowship and AP acknowledges DU and DST for PURSE grant for financial.

Extracellular calmodulin regulates growth and cAMP-mediated chemotaxis in Dictyostelium discoideum

International Nuclear Information System (INIS)

O’Day, Danton H.; Huber, Robert J.; Suarez, Andres

2012-01-01

Highlights: ► Extracellular calmodulin is present throughout growth and development in Dictyostelium. ► Extracellular calmodulin localizes within the ECM during development. ► Extracellular calmodulin inhibits cell proliferation and increases chemotaxis. ► Extracellular calmodulin exists in eukaryotic microbes. ► Extracellular calmodulin may be functionally as important as intracellular calmodulin. -- Abstract: The existence of extracellular calmodulin (CaM) has had a long and controversial history. CaM is a ubiquitous calcium-binding protein that has been found in every eukaryotic cell system. Calcium-free apo-CaM and Ca 2+ /CaM exert their effects by binding to and regulating the activity of CaM-binding proteins (CaMBPs). Most of the research done to date on CaM and its CaMBPs has focused on their intracellular functions. The presence of extracellular CaM is well established in a number of plants where it functions in proliferation, cell wall regeneration, gene regulation and germination. While CaM has been detected extracellularly in several animal species, including frog, rat, rabbit and human, its extracellular localization and functions are less well established. In contrast the study of extracellular CaM in eukaryotic microbes remains to be done. Here we show that CaM is constitutively expressed and secreted throughout asexual development in Dictyostelium where the presence of extracellular CaM dose-dependently inhibits cell proliferation but increases cAMP mediated chemotaxis. During development, extracellular CaM localizes within the slime sheath where it coexists with at least one CaMBP, the matricellular CaM-binding protein CyrA. Coupled with previous research, this work provides direct evidence for the existence of extracellular CaM in the Dictyostelium and provides insight into its functions in this model amoebozoan.

Epstein-Barr virus (EBV) provides survival factors to EBV+ diffuse large B-cell lymphoma (DLBCL) lines and modulates cytokine induced specific chemotaxis in EBV+  DLBCL.

Science.gov (United States)

Wu, Liang; Ehlin-Henriksson, Barbro; Zhou, Xiaoying; Zhu, Hong; Ernberg, Ingemar; Kis, Lorand L; Klein, George

2017-12-01

Diffuse large B-cell lymphoma (DLBCL), the most common type of malignant lymphoma, accounts for 30% of adult non-Hodgkin lymphomas. Epstein-Barr virus (EBV) -positive DLBCL of the elderly is a newly recognized subtype that accounts for 8-10% of DLBCLs in Asian countries, but is less common in Western populations. Five DLBCL-derived cell lines were employed to characterize patterns of EBV latent gene expression, as well as response to cytokines and chemotaxis. Interleukin-4 and interleukin-21 modified LMP1, EBNA1 and EBNA2 expression depending on cell phenotype and type of EBV latent programme (type I, II or III). These cytokines also affected CXCR4- or CCR7-mediated chemotaxis in two of the cell lines, Farage (type III) and Val (type II). Further, we investigated the effect of EBV by using dominant-negative EBV nuclear antigen 1(dnEBNA1) to eliminate EBV genomes. This resulted in decreased chemotaxis. By employing an alternative way to eliminate EBV genomes, Roscovitine, we show an increase of apoptosis in the EBV-positive lines. These results show that EBV plays an important role in EBV-positive DLBCL lines with regard to survival and chemotactic response. Our findings provide evidence for the impact of microenvironment on EBV-carrying DLBCL cells and might have therapeutic implications. © 2017 John Wiley & Sons Ltd.

The Pseudomonas aeruginosa chemotaxis methyltransferase CheR1 impacts on bacterial surface sampling.

Directory of Open Access Journals (Sweden)

Juliane Schmidt

Full Text Available The characterization of factors contributing to the formation and development of surface-associated bacterial communities known as biofilms has become an area of intense interest since biofilms have a major impact on human health, the environment and industry. Various studies have demonstrated that motility, including swimming, swarming and twitching, seems to play an important role in the surface colonization and establishment of structured biofilms. Thereby, the impact of chemotaxis on biofilm formation has been less intensively studied. Pseudomonas aeruginosa has a very complex chemosensory system with two Che systems implicated in flagella-mediated motility. In this study, we demonstrate that the chemotaxis protein CheR1 is a methyltransferase that binds S-adenosylmethionine and transfers a methyl group from this methyl donor to the chemoreceptor PctA, an activity which can be stimulated by the attractant serine but not by glutamine. We furthermore demonstrate that CheR1 does not only play a role in flagella-mediated chemotaxis but that its activity is essential for the formation and maintenance of bacterial biofilm structures. We propose a model in which motility and chemotaxis impact on initial attachment processes, dispersion and reattachment and increase the efficiency and frequency of surface sampling in P. aeruginosa.

Prostaglandin F2α–F-Prostanoid Receptor Signalling Promotes Neutrophil Chemotaxis via Chemokine (CXC motif) Ligand-1 in Endometrial Adenocarcinoma

Science.gov (United States)

Wallace, Alison E; Sales, Kurt J; Catalano, Roberto D; Anderson, Richard A; Williams, Alistair RW; Wilson, Martin R; Schwarze, Jurgen; Wang, Hongwei; Rossi, Adriano G; Jabbour, Henry N

2009-01-01

The prostaglandin F2α (PGF2α) receptor (FP) is elevated in endometrial adenocarcinoma. This study found that PGF2α signalling via FP regulates expression of chemokine (C-X-C motif) ligand 1 (CXCL1) in endometrial adenocarcinoma cells. Expression of CXCL1 and its receptor, CXCR2, are elevated in cancer tissue as compared to normal endometrium and localised to glandular epithelium, endothelium and stroma. Treatment of Ishikawa cells stably transfected with the FP receptor (FPS cells) with 100nM PGF2α increased CXCL1 promoter activity, mRNA and protein expression, and these effects were abolished by co-treatment of cells with FP antagonist or chemical inhibitors of Gq, EGFR and ERK. Similarly, CXCL1 was elevated in response to 100 nM PGF2α in endometrial adenocarcinoma explant tissue. CXCL1 is a potent neutrophil chemoattractant. The expression of CXCR2 colocalised to neutrophils in endometrial adenocarcinoma and increased neutrophils were present in endometrial adenocarcinoma compared with normal endometrium. Conditioned media from PGF2α-treated FPS cells stimulated neutrophil chemotaxis which could be abolished by CXCL1 protein immunoneutralisation of the conditioned media or antagonism of CXCR2. Finally, xenograft tumours in nude mice arising from inoculation with FPS cells showed increased neutrophil infiltration compared to tumours arising from wild-type cells or following treatment of mice bearing FPS tumours with CXCL1-neutralising antibody. In conclusion, our results demonstrate a novel PGF2α-FP pathway that may regulate the inflammatory microenvironment in endometrial adenocarcinoma via neutrophil chemotaxis. PMID:19549892

Distinct Domains of CheA Confer Unique Functions in Chemotaxis and Cell Length in Azospirillum brasilense Sp7.

Science.gov (United States)

Gullett, Jessica M; Bible, Amber; Alexandre, Gladys

2017-07-01

Chemotaxis is the movement of cells in response to gradients of diverse chemical cues. Motile bacteria utilize a conserved chemotaxis signal transduction system to bias their motility and navigate through a gradient. A central regulator of chemotaxis is the histidine kinase CheA. This cytoplasmic protein interacts with membrane-bound receptors, which assemble into large polar arrays, to propagate the signal. In the alphaproteobacterium Azospirillum brasilense , Che1 controls transient increases in swimming speed during chemotaxis, but it also biases the cell length at division. However, the exact underlying molecular mechanisms for Che1-dependent control of multiple cellular behaviors are not known. Here, we identify specific domains of the CheA1 histidine kinase implicated in modulating each of these functions. We show that CheA1 is produced in two isoforms: a membrane-anchored isoform produced as a fusion with a conserved seven-transmembrane domain of unknown function (TMX) at the N terminus and a soluble isoform similar to prototypical CheA. Site-directed and deletion mutagenesis combined with behavioral assays confirm the role of CheA1 in chemotaxis and implicate the TMX domain in mediating changes in cell length. Fluorescence microscopy further reveals that the membrane-anchored isoform is distributed around the cell surface while the soluble isoform localizes at the cell poles. Together, the data provide a mechanism for the role of Che1 in controlling multiple unrelated cellular behaviors via acquisition of a new domain in CheA1 and production of distinct functional isoforms. IMPORTANCE Chemotaxis provides a significant competitive advantage to bacteria in the environment, and this function has been transferred laterally multiple times, with evidence of functional divergence in different genomic contexts. The molecular principles that underlie functional diversification of chemotaxis in various genomic contexts are unknown. Here, we provide a molecular

PsHint1, associated with the G-protein α subunit PsGPA1, is required for the chemotaxis and pathogenicity of Phytophthora sojae.

Science.gov (United States)

Zhang, Xin; Zhai, Chunhua; Hua, Chenlei; Qiu, Min; Hao, Yujuan; Nie, Pingping; Ye, Wenwu; Wang, Yuanchao

2016-02-01

Zoospore chemotaxis to soybean isoflavones is essential in the early stages of infection by the oomycete pathogen Phytophthora sojae. Previously, we have identified a G-protein α subunit encoded by PsGPA1 which regulates the chemotaxis and pathogenicity of P. sojae. In the present study, we used affinity purification to identify PsGPA1-interacting proteins, including PsHint1, a histidine triad (HIT) domain-containing protein orthologous to human HIT nucleotide-binding protein 1 (HINT1). PsHint1 interacted with both the guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms of PsGPA1. An analysis of the gene-silenced transformants revealed that PsHint1 was involved in the chemotropic response of zoospores to the isoflavone daidzein. During interaction with a susceptible soybean cultivar, PsHint1-silenced transformants displayed significantly reduced infectious hyphal extension and caused a strong cell death in plants. In addition, the transformants displayed defective cyst germination, forming abnormal germ tubes that were highly branched and exhibited apical swelling. These results suggest that PsHint1 not only regulates chemotaxis by interacting with PsGPA1, but also participates in a Gα-independent pathway involved in the pathogenicity of P. sojae. © 2015 BSPP AND JOHN WILEY & SONS LTD.

CXCR3 chemokine receptor-induced chemotaxis in human airway epithelial cells: role of p38 MAPK and PI3K signaling pathways.

Science.gov (United States)

Shahabuddin, Syed; Ji, Rong; Wang, Ping; Brailoiu, Eugene; Dun, Na; Yang, Yi; Aksoy, Mark O; Kelsen, Steven G

2006-07-01

Human airway epithelial cells (HAEC) constitutively express the CXC chemokine receptor CXCR3, which regulates epithelial cell movement. In diseases such as chronic obstructive pulmonary disease and asthma, characterized by denudation of the epithelial lining, epithelial cell migration may contribute to airway repair and reconstitution. This study compared the potency and efficacy of three CXCR3 ligands, I-TAC/CXCL11, IP-10/CXCL10, and Mig/CXCL9, as inducers of chemotaxis in HAEC and examined the underlying signaling pathways involved. Studies were performed in cultured HAEC from normal subjects and the 16-HBE cell line. In normal HAEC, the efficacy of I-TAC-induced chemotaxis was 349 +/- 88% (mean +/- SE) of the medium control and approximately one-half the response to epidermal growth factor, a highly potent chemoattractant. In normal HAEC, Mig, IP-10, and I-TAC induced chemotaxis with similar potency and a rank order of efficacy of I-TAC = IP-10 > Mig. Preincubation with pertussis toxin completely blocked CXCR3-induced migration. Of interest, intracellular [Ca(2+)] did not rise in response to I-TAC, IP-10, or Mig. I-TAC induced a rapid phosphorylation (5-10 min) of two of the three MAPKs, i.e., p38 and ERK1/2. Pretreatment of HAEC with the p38 inhibitor SB 20358 or the PI3K inhibitor wortmannin dose-dependently inhibited the chemotactic response to I-TAC. In contrast, the ERK1/2 inhibitor U0126 had no effect on chemotaxis. These data indicate that in HAEC, CXCR3-mediated chemotaxis involves a G protein, which activates both the p38 MAPK and PI3K pathways in a calcium-independent fashion.

Shewanella oneidensis MR-1 chemotaxis proteins and electron-transport chain components essential for congregation near insoluble electron acceptors.

Science.gov (United States)

Harris, H Wayne; El-Naggar, Mohamed Y; Nealson, Kenneth H

2012-12-01

Shewanella oneidensis MR-1 cells utilize a behaviour response called electrokinesis to increase their speed in the vicinity of IEAs (insoluble electron acceptors), including manganese oxides, iron oxides and poised electrodes [Harris, El-Naggar, Bretschger, Ward, Romine, Obraztsova and Nealson (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 326-331]. However, it is not currently understood how bacteria remain in the vicinity of the IEA and accumulate both on the surface and in the surrounding medium. In the present paper, we provide results indicating that cells that have contacted the IEAs swim faster than those that have not recently made contact. In addition, fast-swimming cells exhibit an enhancement of swimming reversals leading to rapid non-random accumulation of cells on, and adjacent to, mineral particles. We call the observed accumulation near IEAs 'congregation'. Congregation is eliminated by the loss of a critical gene involved with EET (extracellular electron transport) (cymA, SO_4591) and is altered or eliminated in several deletion mutants of homologues of genes that are involved with chemotaxis or energy taxis in Escherichia coli. These genes include chemotactic signal transduction protein (cheA-3, SO_3207), methyl-accepting chemotaxis proteins with the Cache domain (mcp_cache, SO_2240) or the PAS (Per/Arnt/Sim) domain (mcp_pas, SO_1385). In the present paper, we report studies of S. oneidensis MR-1 that lend some insight into how microbes in this group can 'sense' the presence of a solid substrate such as a mineral surface, and maintain themselves in the vicinity of the mineral (i.e. via congregation), which may ultimately lead to attachment and biofilm formation.

Evidence for methyl group transfer between the methyl-accepting chemotaxis proteins in Bacillus subtilis

International Nuclear Information System (INIS)

Bedale, W.A.; Nettleton, D.O.; Sopata, C.S.; Thoelke, M.S.; Ordal, G.W.

1988-01-01

The authors present evidence for methyl (as methyl or methoxy) transfer from the methyl-accepting chemotaxis proteins H1 and possibly H3 of Bacillus subtilis to the methyl-accepting chemotaxis protein H2. This methyl transfer, which has been observed in vitro was strongly stimulated by the chemoattractant aspartate and thus may plan an important role in the sensory processing system of this organism. Although radiolabeling of H1 and H3 began at once after the addition of [ 3 H] methionine, radiolabeling of H2 showed a lag. Furthermore, the addition of excess nonradioactive methionine caused immediate exponential delabeling of H1 and H3 while labeling of H2 continued to increase. Methylation of H2 required the chemotactic methyltransferase, probably to first methylate H1 and H3. Aspartate caused increased labeling of H2 and strongly decreased labeling of H1 and H3 after the addition of nonradioactive methionine. Without the addition of nonradioactive methionine, aspartate caused demethylation of H1 and to a lesser extent H3, with an approximately equal increase of methylation of H2

Feeding ducks, bacterial chemotaxis, and the Gini index

Science.gov (United States)

Peaudecerf, François J.; Goldstein, Raymond E.

2015-08-01

Classic experiments on the distribution of ducks around separated food sources found consistency with the "ideal free" distribution in which the local population is proportional to the local supply rate. Motivated by this experiment and others, we examine the analogous problem in the microbial world: the distribution of chemotactic bacteria around multiple nearby food sources. In contrast to the optimization of uptake rate that may hold at the level of a single cell in a spatially varying nutrient field, nutrient consumption by a population of chemotactic cells will modify the nutrient field, and the uptake rate will generally vary throughout the population. Through a simple model we study the distribution of resource uptake in the presence of chemotaxis, consumption, and diffusion of both bacteria and nutrients. Borrowing from the field of theoretical economics, we explore how the Gini index can be used as a means to quantify the inequalities of uptake. The redistributive effect of chemotaxis can lead to a phenomenon we term "chemotactic levelling," and the influence of these results on population fitness are briefly considered.

Suppression of chemotaxis by SSeCKS via scaffolding of phosphoinositol phosphates and the recruitment of the Cdc42 GEF, Frabin, to the leading edge.

Science.gov (United States)

Ko, Hyun-Kyung; Guo, Li-wu; Su, Bing; Gao, Lingqiu; Gelman, Irwin H

2014-01-01

Chemotaxis is controlled by interactions between receptors, Rho-family GTPases, phosphatidylinositol 3-kinases, and cytoskeleton remodeling proteins. We investigated how the metastasis suppressor, SSeCKS, attenuates chemotaxis. Chemotaxis activity inversely correlated with SSeCKS levels in mouse embryo fibroblasts (MEF), DU145 and MDA-MB-231 cancer cells. SSeCKS loss induced chemotactic velocity and linear directionality, correlating with replacement of leading edge lamellipodia with fascin-enriched filopodia-like extensions, the formation of thickened longitudinal F-actin stress fibers reaching to filopodial tips, relative enrichments at the leading edge of phosphatidylinositol (3,4,5)P3 (PIP3), Akt, PKC-ζ, Cdc42-GTP and active Src (SrcpoY416), and a loss of Rac1. Leading edge lamellipodia and chemotaxis inhibition in SSeCKS-null MEF could be restored by full-length SSeCKS or SSeCKS deleted of its Src-binding domain (ΔSrc), but not by SSeCKS deleted of its three MARCKS (myristylated alanine-rich C kinase substrate) polybasic domains (ΔPBD), which bind PIP2 and PIP3. The enrichment of activated Cdc42 in SSeCKS-null leading edge filopodia correlated with recruitment of the Cdc42-specific guanine nucleotide exchange factor, Frabin, likely recruited via multiple PIP2/3-binding domains. Frabin knockdown in SSeCKS-null MEF restores leading edge lamellipodia and chemotaxis inhibition. However, SSeCKS failed to co-immunoprecipitate with Rac1, Cdc42 or Frabin. Consistent with the notion that chemotaxis is controlled by SSeCKS-PIP (vs. -Src) scaffolding activity, constitutively-active phosphatidylinositol 3-kinase could override the ability of the Src inhibitor, SKI-606, to suppress chemotaxis and filopodial enrichment of Frabin in SSeCKS-null MEF. Our data suggest a role for SSeCKS in controlling Rac1 vs. Cdc42-induced cellular dynamics at the leading chemotactic edge through the scaffolding of phospholipids and signal mediators, and through the reorganization of the

The role of cGMP and the rear of the cell in Dictyostelium chemotaxis and cell streaming

NARCIS (Netherlands)

Veltman, Douwe M.; van Haastert, Peter J. M.

2008-01-01

During chemotaxis, pseudopod extensions lead the cell towards the source of attractant. The role of actin-filled pseudopodia at the front of the cell is well recognized, whereas the function of the rear of the cell in chemotaxis and cell-cell interactions is less well known. Dictyostelium cell

Methyl group turnover on methyl-accepting chemotaxis proteins during chemotaxis by Bacillus subtilis

International Nuclear Information System (INIS)

Thoelke, M.S.; Casper, J.M.; Ordal, G.W.

1990-01-01

The addition of attractant to Bacillus subtilis briefly exposed to radioactive methionine causes an increase of labeling of the methyl-accepting chemotaxis proteins. The addition of attractant to cells radiolabeled for longer times shows no change in the extent of methylation. Therefore, the increase in labeling for the briefly labeled cells is due to an increased turnover of methyl groups caused by attractant. All amino acids gave enhanced turnover. This turnover lasted for a prolonged time, probably spanning the period of smooth swimming caused by the attractant addition. Repellent did not affect the turnover when added alone or simultaneously with attractant. Thus, for amino acid attractants, the turnover is probably the excitatory signal, which is seen to extend long into or throughout the adaptation period, not just at the start of it

CO2 degassing in the Hartoušov mofette area, western Eger Rift, imaged by CO2 mapping and geoelectrical and gravity surveys

Czech Academy of Sciences Publication Activity Database

Nickschick, T.; Kämpf, H.; Flechsig, C.; Mrlina, Jan; Heinicke, J.

2015-01-01

Roč. 104, č. 8 (2015), s. 2107-2129 ISSN 1437-3254 R&D Projects: GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : Eger Rift * Cheb Basin * magmatic CO2 * CO2 gas flux studies * geoelectrics * gravity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.133, year: 2015

Fluid flow and particle dynamics inside an evaporating droplet containing live bacteria displaying chemotaxis.

Science.gov (United States)

Thokchom, Ashish Kumar; Swaminathan, Rajaram; Singh, Anugrah

2014-10-21

Evaporation-induced particle deposition patterns like coffee rings provide easy visual identification that is beneficial for developing inexpensive and simple diagnostic devices for detecting pathogens. In this study, the effect of chemotaxis on such pattern formation has been realized experimentally in drying droplets of bacterial suspensions. We have investigated the velocity field, concentration profile, and deposition pattern in the evaporating droplet of Escherichia coli suspension in the presence and absence of nutrients. Flow visualization experiments using particle image velocimetry (PIV) were carried out with E. coli bacteria as biological tracer particles. Experiments were conducted for suspensions of motile (live) as well as nonmotile (dead) bacteria. In the absence of any nutrient gradient like sugar on the substrate, both types of bacterial suspension showed two symmetric convection cells and a ring like deposition of particles after complete evaporation. Interestingly, the droplet containing live bacterial suspension showed a different velocity field when the sugar was placed at the base of the droplet. This can be attributed to the chemoattractant nature of the sugar, which induced chemotaxis among live bacteria targeted toward the nutrient site. Deposition of the suspended bacteria was also displaced toward the nutrient site as the evaporation proceeded. Our experiments demonstrate that both velocity fields and concentration patterns can be altered by chemotaxis to modify the pattern formation in evaporating droplet containing live bacteria. These results highlight the role of bacterial chemotaxis in modifying coffee ring patterns.

cDNA-AFLP analysis of differential gene expression related to cell chemotactic and encystment of Azospirillum brasilense.

Science.gov (United States)

Li, Huamin; Cui, Yanhua; Wu, Lixian; Tu, Ran; Chen, Sanfeng

2011-12-20

Our previous study indicated org35 was involved in chemotaxis and interacted with nitrogen fixation transcriptional activator NifA via PAS domain. In order to reveal the role of org35 in nitrogen regulation, the downstream target genes of org35 were identified. We here report differentially expressed genes in org35 mutants comparing with wild type Sp7 by means of cDNA-AFLP. Four up-regulated transcript-derived fragments (TDFs) homologues of chemotaxis transduction proteins were found, including CheW, methyl-accepting chemotaxis protein and response regulator CheY-like receiver. Three distinct TDFs (AB46, AB58 and AB63) were similar to PHB de-polymerase C-terminus, cell shape-determining protein and flagellin domain protein. And 11 TDFs showed similarities with signal transduction proteins, including homologous protein of the nitrogen regulation protein NtrY and nitrate/nitrite response regulator protein NarL. These data suggested that the Azospirillum brasilense org35 was a multi-effecter and involved in chemotaxis, cyst development and regulation of nitrogen fixation. Copyright © 2010 Elsevier GmbH. All rights reserved.

α-1 Antitrypsin regulates human neutrophil chemotaxis induced by soluble immune complexes and IL-8.

LENUS (Irish Health Repository)

Bergin, David A

2010-12-01

Hereditary deficiency of the protein α-1 antitrypsin (AAT) causes a chronic lung disease in humans that is characterized by excessive mobilization of neutrophils into the lung. However, the reason for the increased neutrophil burden has not been fully elucidated. In this study we have demonstrated using human neutrophils that serum AAT coordinates both CXCR1- and soluble immune complex (sIC) receptor-mediated chemotaxis by divergent pathways. We demonstrated that glycosylated AAT can bind to IL-8 (a ligand for CXCR1) and that AAT-IL-8 complex formation prevented IL-8 interaction with CXCR1. Second, AAT modulated neutrophil chemotaxis in response to sIC by controlling membrane expression of the glycosylphosphatidylinositol-anchored (GPI-anchored) Fc receptor FcγRIIIb. This process was mediated through inhibition of ADAM-17 enzymatic activity. Neutrophils isolated from clinically stable AAT-deficient patients were characterized by low membrane expression of FcγRIIIb and increased chemotaxis in response to IL-8 and sIC. Treatment of AAT-deficient individuals with AAT augmentation therapy resulted in increased AAT binding to IL-8, increased AAT binding to the neutrophil membrane, decreased FcγRIIIb release from the neutrophil membrane, and normalization of chemotaxis. These results provide new insight into the mechanism underlying the effect of AAT augmentation therapy in the pulmonary disease associated with AAT deficiency.

Chemotaxis to cyclic AMP and folic acid is mediated by different G proteins in Dictyostelium discoideum

NARCIS (Netherlands)

Kesbeke, Fanja; Haastert, Peter J.M. van; Wit, René J.W. de; Snaar-Jagalska, B. Ewa

1990-01-01

Mutant Frigid A (fgdA) of Dictyostelium discoideum is defective in a functional Gα2 subunit of a G protein and is characterized by a complete blockade of the cyclic AMP-mediated sensory transduction steps, including cyclic AMP relay, chemotaxis and the cyclic GMP response. Folic acid-mediated

Transducer Like Proteins of Campylobacter jejuni 81-176: Role in chemotaxis and colonization of the chicken gastrointestinal tract

Directory of Open Access Journals (Sweden)

Gireesh eRajashekara

2015-05-01

Full Text Available Transducer Like Proteins (Tlps, also known as Methyl accepting chemotaxis proteins (MCP, enable enteric pathogens to respond to changing nutrient levels in the environment by mediating taxis towards or away from specific chemoeffector molecules such as nutrients. Despite recent advances in the characterization of chemotaxis responses in Campylobacter jejuni, the impact of Tlps on the adaptation of this pathogen to disparate niches and hosts is not fully characterized. The latter is particularly evident in the case of C. jejuni 81-176, a strain that is known to be highly invasive. Furthermore, the cytoplasmic group C Tlps (Tlp5, 6, and 8 was not extensively evaluated. Here, we investigated the role of C. jejuni 81-176 Tlps in chemotaxis towards various substrates, biofilm formation, in vitro interaction with human intestinal cells, and chicken colonization. We found that the ∆tlp6 and ∆tlp10 mutants exhibited decreased chemotaxis towards aspartate whereas the ∆tlp6 mutant displayed a decreased chemotaxis towards Tri-Carboxylic Acid (TCA cycle intermediates such as pyruvate, isocitrate, and succinate. Our findings also corroborated that more than one Tlp is involved in mediating chemotaxis towards the same nutrient. The deletion of tlps affected important phenotypes such as motility, biofilm formation, and invasion of human intestinal epithelial cells (INT-407. The ∆tlp8 mutant displayed increased motility in soft agar and showed decreased biofilm formation. The ∆tlp8 and ∆tlp9 mutants were significantly defective in invasion in INT-407 cells. The ∆tlp10 mutant was defective in colonization of the chicken proximal and distal gastrointestinal tract, while the ∆tlp6 and ∆tlp8 mutants showed reduced colonization of the duodenum and jejunum. Our results highlight the importance of Tlps in C. jejuni’s adaptation and pathobiology.

[Experimental study of the effects of impulse-electric discharge on chemotaxis and cytoadhesion of urinary infection pathogens].

Science.gov (United States)

Kuderinov, S K; Azizov, I S; Turgunov, E M; Shambilova, N A

2006-01-01

The aim of the experimental study was to evaluate effects of impulse-electric discharge in liquid on chemotaxis and cytoadhesion of urinary infection pathogens. Chemotaxis was determined in respect to the lung, liver, spleen, kidney, ureter, urinary bladder, urethra of white mice by S. Likholetov's modified method. Cytoadhesion was assessed by V. Brilis. The experiments show that the impulse-electric discharge holds promise for urological practice.

Chemotaxis in the cellular slime molds : I. The effect of temperature

NARCIS (Netherlands)

Konijn, Theo M.

1965-01-01

The effect of temperature on chemotaxis in the cellular slime mold Dictyostelium discoideum has been studied by incubating small populations of washed myxamoebae at different temperatures. Droplets containing a cell suspension of known density were deposited on a hydrophobic agar surface. The

Architecture and temporal variations of a terrestrial CO2 degassing site using electric resistivity tomography and selfpotential

Czech Academy of Sciences Publication Activity Database

Nickschick, T.; Flechsig, C.; Meinel, C.; Mrlina, Jan; Kämpf, H.

2017-01-01

Roč. 106, č. 8 (2017), s. 2915-2926 ISSN 1437-3254 Institutional support: RVO:67985530 Keywords : Eger rift * ERT * CO2 gax flux * Cheb Basin * mofettes Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 2.283, year: 2016

Influence of standard and novel LTB4 analogs on human neutrophil chemotaxis measured by the multiwell cap assay.

Science.gov (United States)

Psychoyos, S; Uziel-Fusi, S; Bhagwat, S; Morrissey, M M

1989-11-30

Standard and novel LTB4 analogs were tested for neutrophil chemoattractant activity using the multiwell cap assay (Evans et al. (1986) Biosc. Rep. 6, 1041). The assay uses disposable equipment and measures chemotaxis by the number of cells able to migrate across the full thickness of cellulose nitrate filters. Under standard conditions (90 min incubation at 37 degrees C in buffer containing 2% bovine albumin), LTB4 and 6-cis-LTB1 had EC50 values of 3.5 and 15,000 nM, respectively. 20-hydroxy-LTB4 was equipotent with LTB4 and exhibited a similar biphasic chemotactic response, however, only one third of the number of cells migrated through the filter. 20-carboxy-LTB4 was inactive up to 1,000 nM. 5-desoxy-((6,7)-cis-cyclopropyl)-LTB2, (6,7)-benzo-LTB2 and 5-desoxy-(8,10)-LTB2 had EC50 values of 11,300, 50,000 and 84,000 nM, respectively. Checkerboard analysis indicated a chemokinetic component of 42% for LTB4 at a concentration causing peak chemotaxis. Reduction of albumin in the buffer to 0.5% increased the apparent potencies of LTB4 and 6-cis-LTB1 five-fold. Since LTB4 is a mediator of inflammation, various anti-inflammatory agents were tested at peak concentrations observed in vivo for in vitro inhibition of LTB4-stimulated chemotaxis in the presence of 0.5% albumin. Under the conditions of the assay, chloroquine diphosphate, dexamethasone, indomethacin, penicillamine, piroxicam and diclofenac sodium were inactive; gold sodium thiomalate was inhibitory (IC50 = 20 microM).

Role of Shwachman-Bodian-Diamond syndrome protein in translation machinery and cell chemotaxis: a comparative genomics approach

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Vasieva O

2011-09-01

Full Text Available Olga VasievaInstitute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom; Fellowship for the Interpretation of Genomes, Burr Ridge, IL, USAAbstract: Shwachman-Bodian-Diamond syndrome (SBDS is linked to a mutation in a single gene. The SBDS proinvolved in RNA metabolism and ribosome-associated functions, but SBDS mutation is primarily linked to a defect in polymorphonuclear leukocytes unable to orient correctly in a spatial gradient of chemoattractants. Results of data mining and comparative genomic approaches undertaken in this study suggest that SBDS protein is also linked to tRNA metabolism and translation initiation. Analysis of crosstalk between translation machinery and cytoskeletal dynamics provides new insights into the cellular chemotactic defects caused by SBDS protein malfunction. The proposed functional interactions provide a new approach to exploit potential targets in the treatment and monitoring of this disease.Keywords: Shwachman-Bodian-Diamond syndrome, wybutosine, tRNA, chemotaxis, translation, genomics, gene proximity

The impact of odor–reward memory on chemotaxis in larval Drosophila

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Schleyer, Michael; Reid, Samuel F.; Pamir, Evren; Saumweber, Timo; Paisios, Emmanouil; Davies, Alexander

2015-01-01

How do animals adaptively integrate innate with learned behavioral tendencies? We tackle this question using chemotaxis as a paradigm. Chemotaxis in the Drosophila larva largely results from a sequence of runs and oriented turns. Thus, the larvae minimally need to determine (i) how fast to run, (ii) when to initiate a turn, and (iii) where to direct a turn. We first report how odor-source intensities modulate these decisions to bring about higher levels of chemotactic performance for higher odor-source intensities during innate chemotaxis. We then examine whether the same modulations are responsible for alterations of chemotactic performance by learned odor “valence” (understood throughout as level of attractiveness). We find that run speed (i) is neither modulated by the innate nor by the learned valence of an odor. Turn rate (ii), however, is modulated by both: the higher the innate or learned valence of the odor, the less often larvae turn whenever heading toward the odor source, and the more often they turn when heading away. Likewise, turning direction (iii) is modulated concordantly by innate and learned valence: turning is biased more strongly toward the odor source when either innate or learned valence is high. Using numerical simulations, we show that a modulation of both turn rate and of turning direction is sufficient to account for the empirically found differences in preference scores across experimental conditions. Our results suggest that innate and learned valence organize adaptive olfactory search behavior by their summed effects on turn rate and turning direction, but not on run speed. This work should aid studies into the neural mechanisms by which memory impacts specific aspects of behavior. PMID:25887280

Chemotaxis of Dictyostelium discoideum: Collective Oscillation of Cellular Contacts

Science.gov (United States)

Schäfer, Edith; Tarantola, Marco; Polo, Elena; Westendorf, Christian; Oikawa, Noriko; Bodenschatz, Eberhard; Geil, Burkhard; Janshoff, Andreas

2013-01-01

Chemotactic responses of Dictyostelium discoideum cells to periodic self-generated signals of extracellular cAMP comprise a large number of intricate morphological changes on different length scales. Here, we scrutinized chemotaxis of single Dictyostelium discoideum cells under conditions of starvation using a variety of optical, electrical and acoustic methods. Amebas were seeded on gold electrodes displaying impedance oscillations that were simultaneously analyzed by optical video microscopy to relate synchronous changes in cell density, morphology, and distance from the surface to the transient impedance signal. We found that starved amebas periodically reduce their overall distance from the surface producing a larger impedance and higher total fluorescence intensity in total internal reflection fluorescence microscopy. Therefore, we propose that the dominant sources of the observed impedance oscillations observed on electric cell-substrate impedance sensing electrodes are periodic changes of the overall cell-substrate distance of a cell. These synchronous changes of the cell-electrode distance were also observed in the oscillating signal of acoustic resonators covered with amebas. We also found that periodic cell-cell aggregation into transient clusters correlates with changes in the cell-substrate distance and might also contribute to the impedance signal. It turned out that cell-cell contacts as well as cell-substrate contacts form synchronously during chemotaxis of Dictyostelium discoideum cells. PMID:23349816

Evidence for bacterial chemotaxis to cyanobacteria from a radioassay technique

International Nuclear Information System (INIS)

Kangatharalingam, N.; Wang, Lizhu; Priscu, J.C.

1991-01-01

Lyngbya birgei and Aphanizomenon flos-aquae elicited a significant chemotactic attraction of Aeromonas hydrophila compared with controls lacking cyanobacteria. There was a positive exponential relationship between biomass (chlorophyll a) of L. birgei and A. flos-aquae and chemotactic attraction of A. hydrophila. The assay equipment was simple and reliable and could be used to study bacterial chemotaxis in other species in situ

The impact of odor-reward memory on chemotaxis in larval Drosophila.

Science.gov (United States)

Schleyer, Michael; Reid, Samuel F; Pamir, Evren; Saumweber, Timo; Paisios, Emmanouil; Davies, Alexander; Gerber, Bertram; Louis, Matthieu

2015-05-01

How do animals adaptively integrate innate with learned behavioral tendencies? We tackle this question using chemotaxis as a paradigm. Chemotaxis in the Drosophila larva largely results from a sequence of runs and oriented turns. Thus, the larvae minimally need to determine (i) how fast to run, (ii) when to initiate a turn, and (iii) where to direct a turn. We first report how odor-source intensities modulate these decisions to bring about higher levels of chemotactic performance for higher odor-source intensities during innate chemotaxis. We then examine whether the same modulations are responsible for alterations of chemotactic performance by learned odor "valence" (understood throughout as level of attractiveness). We find that run speed (i) is neither modulated by the innate nor by the learned valence of an odor. Turn rate (ii), however, is modulated by both: the higher the innate or learned valence of the odor, the less often larvae turn whenever heading toward the odor source, and the more often they turn when heading away. Likewise, turning direction (iii) is modulated concordantly by innate and learned valence: turning is biased more strongly toward the odor source when either innate or learned valence is high. Using numerical simulations, we show that a modulation of both turn rate and of turning direction is sufficient to account for the empirically found differences in preference scores across experimental conditions. Our results suggest that innate and learned valence organize adaptive olfactory search behavior by their summed effects on turn rate and turning direction, but not on run speed. This work should aid studies into the neural mechanisms by which memory impacts specific aspects of behavior. © 2015 Schleyer et al.; Published by Cold Spring Harbor Laboratory Press.

Simvastatin Inhibits IL-5-Induced Chemotaxis and CCR3 Expression of HL-60-Derived and Human Primary Eosinophils.

Science.gov (United States)

Fu, Chia-Hsiang; Tsai, Wan-Chun; Lee, Ta-Jen; Huang, Chi-Che; Chang, Po-Hung; Su Pang, Jong-Hwei

2016-01-01

IL-5-induced chemotaxis of eosinophils is an important feature of allergic airway inflammatory diseases. Simvastatin, a lipid lowering agent, has been shown to exhibit anti-inflammatory and anti-allergic effects. Our aim was to investigate the effect of simvastatin on IL-5-induced eosinophil chemotaxis and its regulatory mechanisms. Eosinophils were derived by treating HL-60 clone 15 (HC15) cells with butyric acid (BA) in an alkaline condition or through direct isolation from human peripheral blood. The expressions of CC chemokine receptor 3 (CCR3) and interleukin (IL)-5 receptors (IL5Rα and β) were analyzed using RT/real-time PCR. The granular proteins were stained using fast green. Eotaxin-induced chemotaxis was measured using a transwell migration assay. CCR3 protein expression was revealed by immunocytochemistry. An animal model of allergic rhinitis was established by challenging Sprague-Dawley® rats repeatedly with ovalbumin. Butyric acid significantly increased the expression of IL5Rα and IL5Rβ, CCR3 and granular proteins in HC15 cells, indicating the maturation of eosinophils (BA-E cells). IL-5 further enhanced the CCR3 expression at both the mRNA and protein levels and the eotaxin-induced chemotaxis of BA-E cells. Simvastatin inhibited the effects of IL-5 on BA-E cells, but not in the presence of mevalonate. Similar results were also exhibited in human primary eosinophils. In vivo animal studies further confirmed that oral simvastatin could significantly suppress the infiltration of eosinophils into turbinate tissues of allergic rats. Therefore, simvastatin was demonstrated to inhibit IL-5-induced CCR3 expression and chemotaxis of eosinophils mediated via the mevalonate pathway. We confirmed that simvastatin also reduced eosinophilic infiltration in allergic rhinitis.

Chemotaxis and Actin Oscillations

Science.gov (United States)

Bodenschatz, Eberhard; Hsu, Hsin-Fang; Negrete, Jose; Beta, Carsten; Pumir, Alain; Gholami, Azam; Tarantola, Marco; Westendorf, Christian; Zykov, Vladimir

Recently, self-oscillations of the cytoskeletal actin have been observed in Dictyostelium, a model system for studying chemotaxis. Here we report experimental results on the self-oscillation mechanism and the role of regulatory proteins and myosin II. We stimulate cells rapidly and periodically by using photo un-caging of the chemoattractant in a micro-fluidic device and measured the cellular responses. We found that the response amplitude grows with stimulation strength only in a very narrow region of stimulation, after which the response amplitude reaches a plateau. Moreover, the frequency-response is not constant but rather varies with the strength of external stimuli. To understand the underlying mechanism, we analyzed the polymerization and de-polymerization time in the single cell level. Despite of the large cell-to-cell variability, we found that the polymerization time is independent of external stimuli and the de-polymerization time is prolonged as the stimulation strength increases. Our conclusions will be summarized and the role of noise in the signaling network will be discussed. German Science Foundation CRC 937.

Chemotaxis of Dictyostelium discoideum: collective oscillation of cellular contacts.

Directory of Open Access Journals (Sweden)

Edith Schäfer

Full Text Available Chemotactic responses of Dictyostelium discoideum cells to periodic self-generated signals of extracellular cAMP comprise a large number of intricate morphological changes on different length scales. Here, we scrutinized chemotaxis of single Dictyostelium discoideum cells under conditions of starvation using a variety of optical, electrical and acoustic methods. Amebas were seeded on gold electrodes displaying impedance oscillations that were simultaneously analyzed by optical video microscopy to relate synchronous changes in cell density, morphology, and distance from the surface to the transient impedance signal. We found that starved amebas periodically reduce their overall distance from the surface producing a larger impedance and higher total fluorescence intensity in total internal reflection fluorescence microscopy. Therefore, we propose that the dominant sources of the observed impedance oscillations observed on electric cell-substrate impedance sensing electrodes are periodic changes of the overall cell-substrate distance of a cell. These synchronous changes of the cell-electrode distance were also observed in the oscillating signal of acoustic resonators covered with amebas. We also found that periodic cell-cell aggregation into transient clusters correlates with changes in the cell-substrate distance and might also contribute to the impedance signal. It turned out that cell-cell contacts as well as cell-substrate contacts form synchronously during chemotaxis of Dictyostelium discoideum cells.

Incoherent feedforward control governs adaptation of activated ras in a eukaryotic chemotaxis pathway.

Science.gov (United States)

Takeda, Kosuke; Shao, Danying; Adler, Micha; Charest, Pascale G; Loomis, William F; Levine, Herbert; Groisman, Alex; Rappel, Wouter-Jan; Firtel, Richard A

2012-01-03

Adaptation in signaling systems, during which the output returns to a fixed baseline after a change in the input, often involves negative feedback loops and plays a crucial role in eukaryotic chemotaxis. We determined the dynamical response to a uniform change in chemoattractant concentration of a eukaryotic chemotaxis pathway immediately downstream from G protein-coupled receptors. The response of an activated Ras showed near-perfect adaptation, leading us to attempt to fit the results using mathematical models for the two possible simple network topologies that can provide perfect adaptation. Only the incoherent feedforward network accurately described the experimental results. This analysis revealed that adaptation in this Ras pathway is achieved through the proportional activation of upstream components and not through negative feedback loops. Furthermore, these results are consistent with a local excitation, global inhibition mechanism for gradient sensing, possibly with a Ras guanosine triphosphatase-activating protein acting as a global inhibitor.

Decreased numbers of chemotactic factor receptors in chronic neutropenia with defective chemotaxis: spontaneous recovery from the neutrophil abnormalities during early childhood

International Nuclear Information System (INIS)

Yasui, K.; Yamazaki, M.; Miyagawa, Y.; Komiyama, A.; Akabane, T.

1987-01-01

Childhood chronic neutropenia with decreased numbers of chemotactic factor receptors as well as defective chemotaxis was first demonstrated in an 8-month-old girl. Chemotactic factor receptors on neutrophils were assayed using tritiated N-formyl-methionyl-leucyl-phenylalanine ( 3 H-FMLP). The patient's neutrophils had decreased numbers of the receptors: numbers of the receptors were 20,000 (less than 3 SD) as compared with those of control cells of 52,000 +/- 6000 (mean +/- SD) (n = 10). The neutropenia disappeared spontaneously by 28 months of age parallel with the improvement of chemotaxis and increase in numbers of chemotactic factor receptors. These results demonstrate a transient decrease of neutrophil chemotactic factor receptors as one of the pathophysiological bases of a transient defect of neutrophil chemotaxis in this disorder

Sinking, merging and stationary plumes in a coupled chemotaxis-fluid model: a high-resolution numerical approach

KAUST Repository

Chertock, A.

2012-02-02

Aquatic bacteria like Bacillus subtilis are heavier than water yet they are able to swim up an oxygen gradient and concentrate in a layer below the water surface, which will undergo Rayleigh-Taylor-type instabilities for sufficiently high concentrations. In the literature, a simplified chemotaxis-fluid system has been proposed as a model for bio-convection in modestly diluted cell suspensions. It couples a convective chemotaxis system for the oxygen-consuming and oxytactic bacteria with the incompressible Navier-Stokes equations subject to a gravitational force proportional to the relative surplus of the cell density compared to the water density. In this paper, we derive a high-resolution vorticity-based hybrid finite-volume finite-difference scheme, which allows us to investigate the nonlinear dynamics of a two-dimensional chemotaxis-fluid system with boundary conditions matching an experiment of Hillesdon et al. (Bull. Math. Biol., vol. 57, 1995, pp. 299-344). We present selected numerical examples, which illustrate (i) the formation of sinking plumes, (ii) the possible merging of neighbouring plumes and (iii) the convergence towards numerically stable stationary plumes. The examples with stable stationary plumes show how the surface-directed oxytaxis continuously feeds cells into a high-concentration layer near the surface, from where the fluid flow (recurring upwards in the space between the plumes) transports the cells into the plumes, where then gravity makes the cells sink and constitutes the driving force in maintaining the fluid convection and, thus, in shaping the plumes into (numerically) stable stationary states. Our numerical method is fully capable of solving the coupled chemotaxis-fluid system and enabling a full exploration of its dynamics, which cannot be done in a linearised framework. © 2012 Cambridge University Press.

Laminar flow assisted anisotropic bacteria absorption for chemotaxis delivery of bacteria-attached microparticle

Science.gov (United States)

Huh, Keon; Oh, Darong; Son, Seok Young; Yoo, Hyung Jung; Song, Byeonghwa; Cho, Dong-il Dan; Seo, Jong-Mo; Kim, Sung Jae

2016-12-01

The concepts of microrobots has been drawn significant attentions recently since its unprecedented applicability in nanotechnology and biomedical field. Bacteria attached microparticles presented in this work are one of pioneering microrobot technology for self-propulsion or producing kinetic energy from ambient for their motions. Microfluidic device, especially utilizing laminar flow characteristics, were employed for anisotropic attachment of Salmonella typhimurium flagellated chemotactic bacteria to 30 um × 30 um and 50 um × 50 um microparticles that made of biodegradable polymer. Any toxic chemicals or harmful treatments were excluded during the attachment process and it finished within 100 s for the anisotropic attachment. The attachments were directly confirmed by fluorescent intensity changes and SEM visualization. Chemotaxis motions were tracked using aspartate and the maximum velocity of the bacteria-attached microrobot was measured to be 5 um/s which is comparable to prior state of art technologies. This reusable and scalable method could play a key role in chemotaxis delivery of functional microparticles such as drug delivery system.

Effects of exogenous IL-37 on the biological characteristics of human lung adenocarcinoma A549 cells and the chemotaxis of regulatory T cells.

Science.gov (United States)

Chen, Yu-Hua; Zhou, Bi-Yun; Wu, Guo-Cai; Liao, De-Quan; Li, Jing; Liang, Si-Si; Wu, Xian-Jin; Xu, Jun-Fa; Chen, Yong-Hua; Di, Xiao-Qing; Lin, Qiong-Yan

2018-02-14

This study aims to investigate the effects of exogenous interleukin (IL)-37 on the biological characteristics of human lung adenocarcinoma A549 cells and the chemotaxis of regulatory T (Treg) cells. After isolating the CD4+ CD25+ Treg cells from the peripheral blood, flow cytometry was used to detect the purity of the Treg cells. A549 cells were divided into blank (no transfection), empty plasmid (transfection with pIRES2-EGFP empty plasmid) or IL-37 group (transfection with pIRES2-EGFP-IL-37 plasmid). RT-PCR was used to detect mRNA expression of IL-37 and ELISA to determine IL-37 and MMP-9 expressions. Western blotting was applied to detect the protein expressions of PCNA, Ki-67, Cyclin D1, CDK4, cleaved caspase-3 and cleaved caspase-9. MTT assay, flow cytometry, scratch test and transwell assay were performed to detect cell proliferation, cycle, apoptosis, migration and invasion. Effect of exogenous IL-37 on the chemotaxis of Treg cells was measured through transwell assay. Xenograft models in nude mice were eastablished to detect the impact of IL-37 on A549 cells. The IL-37 group had a higher IL-37 expression, cell apoptosis in the early stage and percentage of cells in the G0/G1 phase than the blank and empty plasmid groups. The IL-37 group had a lower MMP-9 expression, optical density (OD), percentage of cells in the S and G2/M phases, migration, invasion and chemotaxis of CD4+CD25+ Foxp3+ Treg cells. The xenograft volume and weight of nude mice in the IL-37 group were lower than those in the blank and empty plasmid groups. Compared with the blank and empty plasmid groups, the IL-37 group had significantly reduced expression of PCNA, Ki-67, Cyclin D1 and CDK4 but elevated expression of cleaved caspase-3 and cleaved caspase-9. Therefore, exogenous IL-37 inhibits the proliferation, migration and invasion of human lung adenocarcinoma A549 cells as well as the chemotaxis of Treg cells while promoting the apoptosis of A549 cells.

Cell-cell interactions mediate cytoskeleton organization and collective endothelial cell chemotaxis.

Science.gov (United States)

Shamloo, Amir

2014-09-01

This study investigates the role of cell-cell and cell-ligand interactions in cytoskeleton organization of endothelial cells (ECs) and their directional migration within a microfluidic device. The migration of ECs in response to a biochemical factor was studied. Mathematical analysis of the cell migration pathways and cellular cytoskeleton revealed that directional migration, migration persistence length, migration speed, and cytoskeletal stress fiber alignment can be mediated by the level of cell contacts as well as the presence or absence of a biochemical polarizing factor. It was shown that in the presence of a biochemical polarizing factor, higher cell density and more frequent cell contacts has a reinforcing effect on collective cell chemotaxis. In contrast, in the absence of a polarizing factor, high cell density can decrease or suppress the ability of the cells to migrate. Also, the correlation of actin stress fiber organization and alignment with directional migration of ECs was investigated. It was shown that in the presence of a biochemical polarizing factor, stress fibers within the cytoskeleton of ECs can be significantly aligned parallel to the gradient direction when the cells have higher level of contacts. The results also show that the organization and alignment of actin stress fibers is mediated by cell adhesion junctions during collective cell migration and introduce cell-cell interactions as a key factor during collective cell chemotaxis. © 2014 Wiley Periodicals, Inc.

Optical tweezers force measurements to study parasites chemotaxis

Science.gov (United States)

de Thomaz, A. A.; Pozzo, L. Y.; Fontes, A.; Almeida, D. B.; Stahl, C. V.; Santos-Mallet, J. R.; Gomes, S. A. O.; Feder, D.; Ayres, D. C.; Giorgio, S.; Cesar, C. L.

2009-07-01

In this work, we propose a methodology to study microorganisms chemotaxis in real time using an Optical Tweezers system. Optical Tweezers allowed real time measurements of the force vectors, strength and direction, of living parasites under chemical or other kinds of gradients. This seems to be the ideal tool to perform observations of taxis response of cells and microorganisms with high sensitivity to capture instantaneous responses to a given stimulus. Forces involved in the movement of unicellular parasites are very small, in the femto-pico-Newton range, about the same order of magnitude of the forces generated in an Optical Tweezers. We applied this methodology to investigate the Leishmania amazonensis (L. amazonensis) and Trypanossoma cruzi (T. cruzi) under distinct situations.

Hem-1 complexes are essential for Rac activation, actin polymerization, and myosin regulation during neutrophil chemotaxis.

Directory of Open Access Journals (Sweden)

Orion D Weiner

2006-02-01

Full Text Available Migrating cells need to make different actin assemblies at the cell's leading and trailing edges and to maintain physical separation of signals for these assemblies. This asymmetric control of activities represents one important form of cell polarity. There are significant gaps in our understanding of the components involved in generating and maintaining polarity during chemotaxis. Here we characterize a family of complexes (which we term leading edge complexes, scaffolded by hematopoietic protein 1 (Hem-1, that organize the neutrophil's leading edge. The Wiskott-Aldrich syndrome protein family Verprolin-homologous protein (WAVE2 complex, which mediates activation of actin polymerization by Rac, is only one member of this family. A subset of these leading edge complexes are biochemically separable from the WAVE2 complex and contain a diverse set of potential polarity-regulating proteins. RNA interference-mediated knockdown of Hem-1-containing complexes in neutrophil-like cells: (a dramatically impairs attractant-induced actin polymerization, polarity, and chemotaxis; (b substantially weakens Rac activation and phosphatidylinositol-(3,4,5-tris-phosphate production, disrupting the (phosphatidylinositol-(3,4,5-tris-phosphate/Rac/F-actin-mediated feedback circuit that organizes the leading edge; and (c prevents exclusion of activated myosin from the leading edge, perhaps by misregulating leading edge complexes that contain inhibitors of the Rho-actomyosin pathway. Taken together, these observations show that versatile Hem-1-containing complexes coordinate diverse regulatory signals at the leading edge of polarized neutrophils, including but not confined to those involving WAVE2-dependent actin polymerization.

Comparison of the effect of timegadine, levamisole, and D-penicillamine on human neutrophil metabolism of endogenous arachidonic acid and chemotaxis

Energy Technology Data Exchange (ETDEWEB)

Nielsen, O.H.; Ahnfelt-Roenne, I. Department of Pharmacology, Leo Pharmaceutical Products, Ballerup; Elmgreen, J.

1988-01-01

The effect of timegadine, a novel experimental antirheumatic drug, on human neutrophil (PMN) 5-lipoxygenase activity and leukotriene B/sub 4/ (LTB/sub 4/) chemotaxis was compared with that of two second-line antiinflammatory drugs, D-penicillamine and levamisole. 1-/sup 14/C-Arachidonic acid (AA) was incorporated into the purified cells until steady state conditions were obtained. After preincubation with serial dilutions of the three drugs, AA release and metabolism was stimulated with calcium ionophore A23187. The radioactive eicosanoids released were extracted and separated by thinlayer chromatography, followed by autoradiography and quantitative laser densitometry. Chemotaxi of PMNs towards LTB/sub 4/ was measured in a modified Boyden chamber. Timegardine showed dose-dependent inhibition of both the 5-lipoxygenase pathway (IC50 3.4 x 10/sup -5/ M), and of chemotaxis (IC50 3 x 10/sup -4/ M). Inhibition of the release of AA from phospholipids, however, occurred only at therapeutically irrelevant doses (millimolar concentrations). Levamisole and D-penicillamine did not inhibit any of the cell functions investigated. Inhibition of both neutrophil motility and cellular synthesis of pro-inflammatory eicosanoids, may thus contribute to the clinical effects of timegadine in rheumatoid arthritis.

Chemokines in the corpus luteum: Implications of leukocyte chemotaxis

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Liptak Amy R

2003-11-01

Full Text Available Abstract Chemokines are small molecular weight peptides responsible for adhesion, activation, and recruitment of leukocytes into tissues. Leukocytes are thought to influence follicular atresia, ovulation, and luteal function. Many studies in recent years have focused attention on the characterization of leukocyte populations within the ovary, the importance of leukocyte-ovarian cell interactions, and more recently, the mechanisms of ovarian leukocyte recruitment. Information about the role of chemokines and leukocyte trafficking (chemotaxis during ovarian function is important to understanding paracrine-autocrine relationships shared between reproductive and immune systems. Recent advances regarding chemokine expression and leukocyte accumulation within the ovulatory follicle and the corpus luteum are the subject of this mini-review.

Thrombospondin-1, -2 and -5 have differential effects on vascular smooth muscle cell physiology

Energy Technology Data Exchange (ETDEWEB)

Helkin, Alex; Maier, Kristopher G. [SUNY Upstate Medical University, Division of Vascular Surgery and Endovascular Services, Syracuse, NY (United States); Department of Veterans Affairs VA Healthcare Network Upstate New York at Syracuse, Syracuse, NY (United States); Gahtan, Vivian, E-mail: gahtanv@upstate.edu [SUNY Upstate Medical University, Division of Vascular Surgery and Endovascular Services, Syracuse, NY (United States); Department of Veterans Affairs VA Healthcare Network Upstate New York at Syracuse, Syracuse, NY (United States)

2015-09-04

Introduction: The thrombospondins (TSPs) are matricellular proteins that exert multifunctional effects by binding cytokines, cell-surface receptors and other proteins. TSPs play important roles in vascular pathobiology and are all expressed in arterial lesions. The differential effects of TSP-1, -2, and -5 represent a gap in knowledge in vascular smooth muscle cell (VSMC) physiology. Our objective is to determine if structural differences of the TSPs imparted different effects on VSMC functions critical to the formation of neointimal hyperplasia. We hypothesize that TSP-1 and -2 induce similar patterns of migration, proliferation and gene expression, while the effects of TSP-5 are different. Methods: Human aortic VSMC chemotaxis was tested for TSP-2 and TSP-5 (1–40 μg/mL), and compared to TSP-1 and serum-free media (SFM) using a modified Boyden chamber. Next, VSMCs were exposed to TSP-1, TSP-2 or TSP-5 (0.2–40 μg/mL). Proliferation was assessed by MTS assay. Finally, VSMCs were exposed to TSP-1, TSP-2, TSP-5 or SFM for 3, 6 or 24 h. Quantitative real-time PCR was performed on 96 genes using a microfluidic card. Statistical analysis was performed by ANOVA or t-test, with p < 0.05 being significant. Results: TSP-1, TSP-2 and TSP-5 at 20 μg/mL all induce chemotaxis 3.1 fold compared to serum-free media. TSP-1 and TSP-2 induced proliferation 53% and 54% respectively, whereas TSP-5 did not. In the gene analysis, overall, cardiovascular system development and function is the canonical pathway most influenced by TSP treatment, and includes multiple growth factors, cytokines and proteases implicated in cellular migration, proliferation, vasculogenesis, apoptosis and inflammation pathways. Conclusions and relevance: The results of this study indicate TSP-1, -2, and -5 play active roles in VSMC physiology and gene expression. Similarly to TSP-1, VSMC chemotaxis to TSP-2 and -5 is dose-dependent. TSP-1 and -2 induces VSMC proliferation, but TSP-5 does not, likely

CYP4F18-Deficient Neutrophils Exhibit Increased Chemotaxis to Complement Component C5a

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Rachel Vaivoda

2015-01-01

Full Text Available CYP4Fs were first identified as enzymes that catalyze hydroxylation of leukotriene B4 (LTB4. CYP4F18 has an unusual expression in neutrophils and was predicted to play a role in regulating LTB4-dependent inflammation. We compared chemotaxis of wild-type and Cyp4f18 knockout neutrophils using an in vitro assay. There was no significant difference in the chemotactic response to LTB4, but the response to complement component C5a increased 1.9–2.25-fold in knockout cells compared to wild-type (P < 0.01. This increase was still observed when neutrophils were treated with inhibitors of eicosanoid synthesis. There were no changes in expression of other CYP4 enzymes in knockout neutrophils that might compensate for loss of CYP4F18 or lead to differences in activity. A mouse model of dextran sodium sulfate colitis was used to investigate the consequences of increased C5a-dependent chemotaxis in vivo, but there was no significant difference in weight loss, disease activity, or colonic tissue myeloperoxidase between wild-type and Cyp4f18 knockout mice. This study demonstrates the limitations of inferring CYP4F function based on an ability to use LTB4 as a substrate, points to expanding roles for CYP4F enzymes in immune regulation, and underscores the in vivo challenges of CYP knockout studies.

The nematode Caenorhabditis elegans displays a chemotaxis behavior to tuberculosis-specific odorants

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Mário F. Neto

2016-08-01

Full Text Available A simple, affordable diagnostic test for pulmonary tuberculosis (TB is urgently needed to improve detection of active Mycobacterium tuberculosis. Recently, it has been suggested that animal behavior can be used as a biosensor to signal the presence of human disease. For example, the giant African pouched rats can detect tuberculosis by sniffing sputum specimens while trained honeybees respond to three of the volatile organic compounds (VOCs detected in the breath of TB positive patients by proboscis extension. However, both rats and honeybees require animal housing facilities and professional trainers, which are outside the scope of most disease testing facilities. Here, we report that the innate olfactory behavioral response of the roundworm nematode Caenorhabditis elegans can be used to detect the TB-specific VOCs methyl p-anisate, methyl nicotinate, methyl phenylacetate and o-phenylanisole, in chemotaxis assays. Dauer larvae, a long-lived stress resistant alternative development state of C. elegans in which the animals can survive for extended periods of time in dry conditions with no food, were also demonstrated to detect the VOCs. We propose that exposing naive dauer larvae to TB-related VOCs and recording their response in this behavioral assay could lead to the development of a new method for TB diagnostics using breath as the sample type. Keywords: Tuberculosis, Caenorhabditis elegans, Chemotaxis, Volatile organic compounds, Diagnostics, Odorants

The chemotaxis regulator pilG of Xylella fastidiosa is required for virulence in Vitis vinifera grapevines

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Type IV pili of X. fastidiosa are regulated by pilG, a response regulator protein putatively involved in chemotaxis-like operon sensing stimuli through signal transduction pathways. To elucidate roles of pilG in pathogenicity of X. fastidiosa, the pilG-deletion mutant and complementary strain contai...

Reconstruction of the Chemotaxis Receptor-Kinase Assembly

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Park, S.; Borbat, P.; Gonzalez-Bonet, G.; Bhatnagar, J.; Pollard, A.; Freed, J.; Bilwes, A.; Crane, B.

2006-01-01

In bacterial chemotaxis, an assembly of transmembrane receptors, the CheA histidine kinase and the adaptor protein CheW processes environmental stimuli to regulate motility. The structure of a Thermotoga maritima receptor cytoplasmic domain defines CheA interaction regions and metal ion-coordinating charge centers that undergo chemical modification to tune receptor response. Dimeric CheA-CheW, defined by crystallography and pulsed ESR, positions two CheWs to form a cleft that is lined with residues important for receptor interactions and sized to clamp one receptor dimer. CheW residues involved in kinase activation map to interfaces that orient the CheW clamps. CheA regulatory domains associate in crystals through conserved hydrophobic surfaces. Such CheA self-contacts align the CheW receptor clamps for binding receptor tips. Linking layers of ternary complexes with close-packed receptors generates a lattice with reasonable component ratios, cooperative interactions among receptors and accessible sites for modification enzymes

The hypoxia factor Hif-1α controls neural crest chemotaxis and epithelial to mesenchymal transition

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Barriga, Elias H.; Maxwell, Patrick H.

2013-01-01

One of the most important mechanisms that promotes metastasis is the stabilization of Hif-1 (hypoxia-inducible transcription factor 1). We decided to test whether Hif-1α also was required for early embryonic development. We focused our attention on the development of the neural crest, a highly migratory embryonic cell population whose behavior has been likened to cancer metastasis. Inhibition of Hif-1α by antisense morpholinos in Xenopus laevis or zebrafish embryos led to complete inhibition of neural crest migration. We show that Hif-1α controls the expression of Twist, which in turn represses E-cadherin during epithelial to mesenchymal transition (EMT) of neural crest cells. Thus, Hif-1α allows cells to initiate migration by promoting the release of cell–cell adhesions. Additionally, Hif-1α controls chemotaxis toward the chemokine SDF-1 by regulating expression of its receptor Cxcr4. Our results point to Hif-1α as a novel and key regulator that integrates EMT and chemotaxis during migration of neural crest cells. PMID:23712262

Motility and chemotaxis mediate the preferential colonization of gastric injury sites by Helicobacter pylori.

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Eitaro Aihara

2014-07-01

Full Text Available Helicobacter pylori (H. pylori is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1 significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB or chemotaxis (ΔcheY. ΔmotB (10(6 failed to colonize ulcerated or healthy stomach tissue. ΔcheY (10(6 colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites

Motility and Chemotaxis Mediate the Preferential Colonization of Gastric Injury Sites by Helicobacter pylori

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Aihara, Eitaro; Closson, Chet; Matthis, Andrea L.; Schumacher, Michael A.; Engevik, Amy C.; Zavros, Yana; Ottemann, Karen M.; Montrose, Marshall H.

2014-01-01

Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (106) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (106) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby biases

A computational model for how cells choose temporal or spatial sensing during chemotaxis.

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Tan, Rui Zhen; Chiam, Keng-Hwee

2018-03-01

Cell size is thought to play an important role in choosing between temporal and spatial sensing in chemotaxis. Large cells are thought to use spatial sensing due to large chemical difference at its ends whereas small cells are incapable of spatial sensing due to rapid homogenization of proteins within the cell. However, small cells have been found to polarize and large cells like sperm cells undergo temporal sensing. Thus, it remains an open question what exactly governs spatial versus temporal sensing. Here, we identify the factors that determines sensing choices through mathematical modeling of chemotactic circuits. Comprehensive computational search of three-node signaling circuits has identified the negative integral feedback (NFB) and incoherent feedforward (IFF) circuits as capable of adaptation, an important property for chemotaxis. Cells are modeled as one-dimensional circular system consisting of diffusible activator, inactivator and output proteins, traveling across a chemical gradient. From our simulations, we find that sensing outcomes are similar for NFB or IFF circuits. Rather than cell size, the relevant parameters are the 1) ratio of cell speed to the product of cell diameter and rate of signaling, 2) diffusivity of the output protein and 3) ratio of the diffusivities of the activator to inactivator protein. Spatial sensing is favored when all three parameters are low. This corresponds to a cell moving slower than the time it takes for signaling to propagate across the cell diameter, has an output protein that is polarizable and has a local-excitation global-inhibition system to amplify the chemical gradient. Temporal sensing is favored otherwise. We also find that temporal sensing is more robust to noise. By performing extensive literature search, we find that our prediction agrees with observation in a wide range of species and cell types ranging from E. coli to human Fibroblast cells and propose that our result is universally applicable.

Deduction of Novel Genes Potentially Involved in Osteoblasts of Rheumatoid Arthritis Using Next-Generation Sequencing and Bioinformatic Approaches

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Yi-Jen Chen

2017-11-01

Full Text Available The role of osteoblasts in peri-articular bone loss and bone erosion in rheumatoid arthritis (RA has gained much attention, and microRNAs are hypothesized to play critical roles in the regulation of osteoblast function in RA. The aim of this study is to explore novel microRNAs differentially expressed in RA osteoblasts and to identify genes potentially involved in the dysregulated bone homeostasis in RA. RNAs were extracted from cultured normal and RA osteoblasts for sequencing. Using the next generation sequencing and bioinformatics approaches, we identified 35 differentially expressed microRNAs and 13 differentially expressed genes with potential microRNA–mRNA interactions in RA osteoblasts. The 13 candidate genes were involved mainly in cell–matrix adhesion, as classified by the Gene Ontology. Two genes of interest identified from RA osteoblasts, A-kinase anchoring protein 12 (AKAP12 and leucin rich repeat containing 15 (LRRC15, were found to express more consistently in the related RA synovial tissue arrays in the Gene Expression Omnibus database, with the predicted interactions with miR-183-5p and miR-146a-5p, respectively. The Ingenuity Pathway Analysis identified AKAP12 as one of the genes involved in protein kinase A signaling and the function of chemotaxis, interconnecting with molecules related to neovascularization. The findings indicate new candidate genes as the potential indicators in evaluating therapies targeting chemotaxis and neovascularization to control joint destruction in RA.

Granulomatous response to Coxiella burnetii, the agent of Q fever: the lessons from gene expression analysis

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delphine efaugaret

2014-12-01

Full Text Available The formation of granulomas is associated with the resolution of Q fever, a zoonosis due to Coxiella burnetii; however the molecular mechanisms of granuloma formation remain poorly understood. We generated human granulomas with peripheral blood mononuclear cells and beads coated with C. burnetii, using BCG extracts as controls. A microarray analysis showed dramatic changes in gene expression in granuloma cells of which more than 50% were commonly modulated genes in response to C. burnetii and BCG. They included M1-related genes and genes related to chemotaxis. The inhibition of the chemokines, CCL2 and CCL5, directly interfered with granuloma formation. C. burnetii granulomas also expressed a specific transcriptional profile that was essentially enriched in genes associated with type I interferon response. Our results showed that granuloma formation is associated with a core of transcriptional response based on inflammatory genes. The specific granulomatous response to C. burnetii is characterized by the activation of type I interferon pathway.

A hybrid two-component system protein from Azospirillum brasilense Sp7 was involved in chemotaxis.

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Cui, Yanhua; Tu, Ran; Wu, Lixian; Hong, Yuanyuan; Chen, Sanfeng

2011-09-20

We here report the sequence and functional analysis of org35 of Azospirillum brasilense Sp7, which was originally identified to be able to interact with NifA in yeast-two-hybrid system. The org35 encodes a hybrid two-component system protein, including N-terminal PAS domains, a histidine kinase (HPK) domain and a response regulator (RR) domain in C-terminal. To determine the function of the Org35, a deletion-insertion mutant in PAS domain [named Sp7353] and a complemental strain Sp7353C were constructed. The mutant had reduced chemotaxis ability compared to that of wild-type, and the complemental strain was similar to the wild-type strain. These data suggested that the A. brasilense org35 played a key role in chemotaxis. Variants containing different domains of the org35 were expressed, and the functions of these domains were studied in vitro. Phosphorylation assays in vitro demonstrated that the HPK domain of Org35 possessed the autokinase activity and that the phosphorylated HPK was able to transfer phosphate groups to the RR domain. The result indicated Org35 was a phosphorylation-communicating protein. Copyright © 2010 Elsevier GmbH. All rights reserved.

Rac1 plays a role in CXCL12 but not CCL3-induced chemotaxis and Rac1 GEF inhibitor NSC23766 has off target effects on CXCR4.

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Mills, Shirley C; Howell, Lesley; Beekman, Andrew; Stokes, Leanne; Mueller, Anja

2018-01-01

Cell migration towards a chemotactic stimulus relies on the re-arrangement of the cytoskeleton, which is triggered by activation of small G proteins RhoA, Rac1 and Cdc42, and leads to formation of lamellopodia and actin polymerisation amongst other effects. Here we show that Rac1 is important for CXCR4 induced chemotaxis but not for CCR1/CCR5 induced chemotaxis. For CXCL12-induced migration via CXCR4, breast cancer MCF-7 cells are reliant on Rac1, similarly to THP-1 monocytes and Jurkat T-cells. For CCL3-induced migration via CCR1 and/or CCR5, Rac1 signalling does not regulate cell migration in either suspension or adherent cells. We have confirmed the involvement of Rac1 with the use of a specific Rac1 blocking peptide. We also used a Rac1 inhibitor EHT 1864 and a Rac1-GEF inhibitor NSC23766 to probe the importance of Rac1 in chemotaxis. Both inhibitors did not block CCL3-induced chemotaxis, but they were able to block CXCL12-induced chemotaxis. This confirms that Rac1 activation is not essential for CCL3-induced migration, however NSC23766 might have secondary effects on CXCR4. This small molecule exhibits agonistic features in internalisation and cAMP assays, whereas it acts as an antagonist for CXCR4 in migration and calcium release assays. Our findings strongly suggest that Rac1 activation is not necessary for CCL3 signalling, and reveal that NSC23766 could be a novel CXCR4 receptor ligand. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

The chemotaxis-like Che1 pathway has an indirect role in adhesive cell properties of Azospirillum brasilense.

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Siuti, Piro; Green, Calvin; Edwards, Amanda Nicole; Doktycz, Mitchel J; Alexandre, Gladys

2011-10-01

The Azospirillum brasilense chemotaxis-like Che1 signal transduction pathway was recently shown to modulate changes in adhesive cell surface properties that, in turn, affect cell-to-cell aggregation and flocculation behaviors rather than flagellar-mediated chemotaxis. Attachment to surfaces and root colonization may be functions related to flocculation. Here, the conditions under which A. brasilense wild-type Sp7 and che1 mutant strains attach to abiotic and biotic surfaces were examined using in vitro attachment and biofilm assays combined with atomic force microscopy and confocal microscopy. The nitrogen source available for growth is found to be a major modulator of surface attachment by A. brasilense and could be promoted in vitro by lectins, suggesting that it depends on interaction with surface-exposed residues within the extracellular matrix of cells. However, Che1-dependent signaling is shown to contribute indirectly to surface attachment, indicating that distinct mechanisms are likely underlying flocculation and attachment to surfaces in A. brasilense. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Analysis of migration rate and chemotaxis of human adipose-derived mesenchymal stem cells in response to LPS and LTA in vitro

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Herzmann, Nicole; Salamon, Achim [Department of Cell Biology, University Medicine Rostock, Schillingallee 69, D-18057 Rostock (Germany); Fiedler, Tomas [Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Schillingallee 70, D-18057 Rostock (Germany); Peters, Kirsten, E-mail: kirsten.peters@med.uni-rostock.de [Department of Cell Biology, University Medicine Rostock, Schillingallee 69, D-18057 Rostock (Germany)

2016-03-15

Mesenchymal stem cells (MSC) are able to stimulate the regeneration of injured tissue. Since bacterial infections are common complications in wound healing, bacterial pathogens and their components come into direct contact with MSC. The interaction with bacterial structures influences the proliferation, differentiation and migratory activity of the MSC, which might be of relevance during regeneration. Studies on MSC migration in response to bacterial components have shown different results depending on the cell type. Here, we analyzed the migration rate and chemotaxis of human adipose-derived MSC (adMSC) in response to the basic cell-wall components lipopolysaccharide (LPS) of Gram-negative bacteria and lipoteichoic acid (LTA) of Gram-positive bacteria in vitro. To this end, we used transwell and scratch assays, as well as a specific chemotaxis assay combined with live-cell imaging. We found no significant influence of LPS or LTA on the migration rate of adMSC in transwell or scratch assays. Furthermore, in the µ-slide chemotaxis assay, the stimulation with LPS did not exert any chemotactic effect on adMSC. - Highlights: • LPS increased the release of IL-6 and IL-8 in adMSC significantly. • The migration rate of adMSC was not influenced by LPS or LTA. • LPS or LTA did not exert a chemotactic effect on adMSC.

Analysis of migration rate and chemotaxis of human adipose-derived mesenchymal stem cells in response to LPS and LTA in vitro

International Nuclear Information System (INIS)

Herzmann, Nicole; Salamon, Achim; Fiedler, Tomas; Peters, Kirsten

2016-01-01

Mesenchymal stem cells (MSC) are able to stimulate the regeneration of injured tissue. Since bacterial infections are common complications in wound healing, bacterial pathogens and their components come into direct contact with MSC. The interaction with bacterial structures influences the proliferation, differentiation and migratory activity of the MSC, which might be of relevance during regeneration. Studies on MSC migration in response to bacterial components have shown different results depending on the cell type. Here, we analyzed the migration rate and chemotaxis of human adipose-derived MSC (adMSC) in response to the basic cell-wall components lipopolysaccharide (LPS) of Gram-negative bacteria and lipoteichoic acid (LTA) of Gram-positive bacteria in vitro. To this end, we used transwell and scratch assays, as well as a specific chemotaxis assay combined with live-cell imaging. We found no significant influence of LPS or LTA on the migration rate of adMSC in transwell or scratch assays. Furthermore, in the µ-slide chemotaxis assay, the stimulation with LPS did not exert any chemotactic effect on adMSC. - Highlights: • LPS increased the release of IL-6 and IL-8 in adMSC significantly. • The migration rate of adMSC was not influenced by LPS or LTA. • LPS or LTA did not exert a chemotactic effect on adMSC.

Low-temperature chemotaxis, halotaxis and chemohalotaxis by the psychrophilic marine bacterium Colwellia psychrerythraea 34H.

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Showalter, G M; Deming, J W

2018-02-01

A variety of ecologically important processes are driven by bacterial motility and taxis, yet these basic bacterial behaviours remain understudied in cold habitats. Here, we present a series of experiments designed to test the chemotactic ability of the model marine psychrophilic bacterium Colwellia psychrerythraea 34H, when grown at optimal temperature and salinity (8°C, 35 ppt) or its original isolation conditions (-1°C, 35 ppt), towards serine and mannose at temperatures from -8°C to 27°C (above its upper growth temperature of 18°C), and at salinities of 15, 35 and 55 ppt (at 8°C and -1°C). Results indicate that C. psychrerythraea 34H is capable of chemotaxis at all temperatures tested, with strongest chemotaxis at the temperature at which it was first grown, whether 8°C or -1°C. This model marine psychrophile also showed significant halotaxis towards 15 and 55 ppt solutions, as well as strong substrate-specific chemohalotaxis. We suggest that such patterns of taxis may enable bacteria to colonize sea ice, position themselves optimally within its extremely cold, hypersaline and temporally fluctuating microenvironments, and respond to various chemical signals therein. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and JohnWiley & Sons Ltd.

Interaction of HmC1q with leech microglial cells: involvement of C1qBP-related molecule in the induction of cell chemotaxis

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Tahtouh Muriel

2012-02-01

Full Text Available Abstract Background In invertebrates, the medicinal leech is considered to be an interesting and appropriate model to study neuroimmune mechanisms. Indeed, this non-vertebrate animal can restore normal function of its central nervous system (CNS after injury. Microglia accumulation at the damage site has been shown to be required for axon sprouting and for efficient regeneration. We characterized HmC1q as a novel chemotactic factor for leech microglial cell recruitment. In mammals, a C1q-binding protein (C1qBP alias gC1qR, which interacts with the globular head of C1q, has been reported to participate in C1q-mediated chemotaxis of blood immune cells. In this study, we evaluated the chemotactic activities of a recombinant form of HmC1q and its interaction with a newly characterized leech C1qBP that acts as its potential ligand. Methods Recombinant HmC1q (rHmC1q was produced in the yeast Pichia pastoris. Chemotaxis assays were performed to investigate rHmC1q-dependent microglia migration. The involvement of a C1qBP-related molecule in this chemotaxis mechanism was assessed by flow cytometry and with affinity purification experiments. The cellular localization of C1qBP mRNA and protein in leech was investigated using immunohistochemistry and in situ hybridization techniques. Results rHmC1q-stimulated microglia migrate in a dose-dependent manner. This rHmC1q-induced chemotaxis was reduced when cells were preincubated with either anti-HmC1q or anti-human C1qBP antibodies. A C1qBP-related molecule was characterized in leech microglia. Conclusions A previous study showed that recruitment of microglia is observed after HmC1q release at the cut end of axons. Here, we demonstrate that rHmC1q-dependent chemotaxis might be driven via a HmC1q-binding protein located on the microglial cell surface. Taken together, these results highlight the importance of the interaction between C1q and C1qBP in microglial activation leading to nerve repair in the medicinal

Interaction of HmC1q with leech microglial cells: involvement of C1qBP-related molecule in the induction of cell chemotaxis.

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Tahtouh, Muriel; Garçon-Bocquet, Annelise; Croq, Françoise; Vizioli, Jacopo; Sautière, Pierre-Eric; Van Camp, Christelle; Salzet, Michel; Nagnan-le Meillour, Patricia; Pestel, Joël; Lefebvre, Christophe

2012-02-22

In invertebrates, the medicinal leech is considered to be an interesting and appropriate model to study neuroimmune mechanisms. Indeed, this non-vertebrate animal can restore normal function of its central nervous system (CNS) after injury. Microglia accumulation at the damage site has been shown to be required for axon sprouting and for efficient regeneration. We characterized HmC1q as a novel chemotactic factor for leech microglial cell recruitment. In mammals, a C1q-binding protein (C1qBP alias gC1qR), which interacts with the globular head of C1q, has been reported to participate in C1q-mediated chemotaxis of blood immune cells. In this study, we evaluated the chemotactic activities of a recombinant form of HmC1q and its interaction with a newly characterized leech C1qBP that acts as its potential ligand. Recombinant HmC1q (rHmC1q) was produced in the yeast Pichia pastoris. Chemotaxis assays were performed to investigate rHmC1q-dependent microglia migration. The involvement of a C1qBP-related molecule in this chemotaxis mechanism was assessed by flow cytometry and with affinity purification experiments. The cellular localization of C1qBP mRNA and protein in leech was investigated using immunohistochemistry and in situ hybridization techniques. rHmC1q-stimulated microglia migrate in a dose-dependent manner. This rHmC1q-induced chemotaxis was reduced when cells were preincubated with either anti-HmC1q or anti-human C1qBP antibodies. A C1qBP-related molecule was characterized in leech microglia. A previous study showed that recruitment of microglia is observed after HmC1q release at the cut end of axons. Here, we demonstrate that rHmC1q-dependent chemotaxis might be driven via a HmC1q-binding protein located on the microglial cell surface. Taken together, these results highlight the importance of the interaction between C1q and C1qBP in microglial activation leading to nerve repair in the medicinal leech.

The Genome of the Toluene-Degrading Pseudomonas veronii Strain 1YdBTEX2 and Its Differential Gene Expression in Contaminated Sand.

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Marian Morales

Full Text Available The natural restoration of soils polluted by aromatic hydrocarbons such as benzene, toluene, ethylbenzene and m- and p-xylene (BTEX may be accelerated by inoculation of specific biodegraders (bioaugmentation. Bioaugmentation mainly involves introducing bacteria that deploy their metabolic properties and adaptation potential to survive and propagate in the contaminated environment by degrading the pollutant. In order to better understand the adaptive response of cells during a transition to contaminated material, we analyzed here the genome and short-term (1 h changes in genome-wide gene expression of the BTEX-degrading bacterium Pseudomonas veronii 1YdBTEX2 in non-sterile soil and liquid medium, both in presence or absence of toluene. We obtained a gapless genome sequence of P. veronii 1YdBTEX2 covering three individual replicons with a total size of 8 Mb, two of which are largely unrelated to current known bacterial replicons. One-hour exposure to toluene, both in soil and liquid, triggered massive transcription (up to 208-fold induction of multiple gene clusters, such as toluene degradation pathway(s, chemotaxis and toluene efflux pumps. This clearly underlines their key role in the adaptive response to toluene. In comparison to liquid medium, cells in soil drastically changed expression of genes involved in membrane functioning (e.g., lipid composition, lipid metabolism, cell fatty acid synthesis, osmotic stress response (e.g., polyamine or trehalose synthesis, uptake of potassium and putrescine metabolism, highlighting the immediate response mechanisms of P. veronii 1YdBTEX2 for successful establishment in polluted soil.

Multiple Regulatory Roles of the Mouse Transmembrane Adaptor Protein NTAL in Gene Transcription and Mast Cell Physiology

Czech Academy of Sciences Publication Activity Database

Polakovičová, Iva; Dráberová, Lubica; Šimíček, Michal; Dráber, Petr

2014-01-01

Roč. 9, č. 8 (2014), e105539 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GBP302/12/G101; GA MŠk LD12073 Institutional support: RVO:68378050 Keywords : mast cells * NTAL * microarray gene-expression profiling * spreading * chemotaxis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2014

Novel methyl transfer during chemotaxis in Bacillus subtilis

International Nuclear Information System (INIS)

Thoelke, M.S.; Kirby, J.R.; Ordal, G.W.

1989-01-01

If Bacillus subtilis is incubated in radioactive methionine in the absence of protein synthesis, the methyl-accepting chemotaxis proteins (MCPs) become radioactively methylated. If the bacteria are further incubated in excess nonradioactive methionine (cold-chased) and then given the attractant aspartate, the MCPs lose about half of their radioactivity due to turnover, in which lower specific activity methyl groups from S-adenosylmethionine (AdoMet) replace higher specific activity ones. Due to the cold-chase, the specific activity of the AdoMet pool is reduced at least 2-fold. If, later, the attractant is removed, higher specific activity methyl groups return to the MCPs. Thus, there must exist an unidentified methyl carrier than can reversibly receive methyl groups from the MCPs. In a similar experiment, labeled cells were transferred to a flow cell and exposed to addition and removal of attractant and of repellent. All four kinds of stimuli were found to cause methanol production. Bacterial with maximally labeled MCPs were exposed to many cycles of addition and removal of attractant; the maximum amount of radioactive methanol was evolved on the third, not the first, cycle. This result suggests that there is a precursor-product relationship between methyl groups on the MCPs and on the unidentified carrier, which might be the direct source of methanol. However, since no methanol was produced when a methyltransferase mutant, whose MCPs were unmethylated, was exposed to addition and removal of attractant or repellent, the methanol must ultimately derive from methylated MCPs

Genetic analysis reveals the identity of the photoreceptor for phototaxis in hormogonium filaments of Nostoc punctiforme.

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Campbell, Elsie L; Hagen, Kari D; Chen, Rui; Risser, Douglas D; Ferreira, Daniela P; Meeks, John C

2015-02-15

In cyanobacterial Nostoc species, substratum-dependent gliding motility is confined to specialized nongrowing filaments called hormogonia, which differentiate from vegetative filaments as part of a conditional life cycle and function as dispersal units. Here we confirm that Nostoc punctiforme hormogonia are positively phototactic to white light over a wide range of intensities. N. punctiforme contains two gene clusters (clusters 2 and 2i), each of which encodes modular cyanobacteriochrome-methyl-accepting chemotaxis proteins (MCPs) and other proteins that putatively constitute a basic chemotaxis-like signal transduction complex. Transcriptional analysis established that all genes in clusters 2 and 2i, plus two additional clusters (clusters 1 and 3) with genes encoding MCPs lacking cyanobacteriochrome sensory domains, are upregulated during the differentiation of hormogonia. Mutational analysis determined that only genes in cluster 2i are essential for positive phototaxis in N. punctiforme hormogonia; here these genes are designated ptx (for phototaxis) genes. The cluster is unusual in containing complete or partial duplicates of genes encoding proteins homologous to the well-described chemotaxis elements CheY, CheW, MCP, and CheA. The cyanobacteriochrome-MCP gene (ptxD) lacks transmembrane domains and has 7 potential binding sites for bilins. The transcriptional start site of the ptx genes does not resemble a sigma 70 consensus recognition sequence; moreover, it is upstream of two genes encoding gas vesicle proteins (gvpA and gvpC), which also are expressed only in the hormogonium filaments of N. punctiforme. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Protein Connectivity in Chemotaxis Receptor Complexes.

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Stephan Eismann

2015-12-01

Full Text Available The chemotaxis sensory system allows bacteria such as Escherichia coli to swim towards nutrients and away from repellents. The underlying pathway is remarkably sensitive in detecting chemical gradients over a wide range of ambient concentrations. Interactions among receptors, which are predominantly clustered at the cell poles, are crucial to this sensitivity. Although it has been suggested that the kinase CheA and the adapter protein CheW are integral for receptor connectivity, the exact coupling mechanism remains unclear. Here, we present a statistical-mechanics approach to model the receptor linkage mechanism itself, building on nanodisc and electron cryotomography experiments. Specifically, we investigate how the sensing behavior of mixed receptor clusters is affected by variations in the expression levels of CheA and CheW at a constant receptor density in the membrane. Our model compares favorably with dose-response curves from in vivo Förster resonance energy transfer (FRET measurements, demonstrating that the receptor-methylation level has only minor effects on receptor cooperativity. Importantly, our model provides an explanation for the non-intuitive conclusion that the receptor cooperativity decreases with increasing levels of CheA, a core signaling protein associated with the receptors, whereas the receptor cooperativity increases with increasing levels of CheW, a key adapter protein. Finally, we propose an evolutionary advantage as explanation for the recently suggested CheW-only linker structures.

Radioassay of granulocyte chemotaxis. Studies of human granulocytes and chemotactic factors. [/sup 51/Cr tracer technique

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Gallin, J I

1974-01-01

The above studies demonstrate that the /sup 51/Cr radiolabel chemotactic assay is a relatively simple and objective means for studying leukocyte chemotaxis in both normal and pathological conditions. Application of this method to studies of normal human chemotaxis revealed a relatively narrow range of normal and little day-to-day variability. Analysis of this variability revealed that there is more variability among the response of different granulocytes to a constant chemotactic stimulus than among the chemotactic activity of different sera to a single cell source. Utilizing the /sup 51/Cr radioassay, the abnormal granulocyte chemotactic behavior reported in Chediak-Higashi syndrome and a patient with recurrent pyogenic infections and mucocutaneous candidiasis has been confirmed. The /sup 51/Cr chemotactic assay has also been used to assess the generation of chemotactic activity from human serum and plasma. The in vitro generation of two distinct chemotactic factors were examined; the complement product (C5a) and kallikrein, an enzyme of the kinin-generating pathway. Kinetic analysis of complement-related chemotactic factor formation, utilizing immune complexes or endotoxin to activate normal sera in the presence or absence of EGTA as well as kinetic analysis of activation of C2-deficient human serum, provided an easy means of distinguishing the classical (antibody-mediated) complement pathway from the alternate pathway. Such kinetic analysis is necessary to detect clinically important abnormalities since, after 60 min of generation time, normal chemotactic activity may be present despite complete absence or inhibition of one complement pathway. The chemotactic factor generated by either pathway of complement activation appears to be predominately attributable to C5a.

A CheR/CheB fusion protein is involved in cyst cell development and chemotaxis in Azospirillum brasilense Sp7.

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Wu, Lixian; Cui, Yanhua; Hong, Yuanyuan; Chen, Sanfeng

2011-12-20

We here report the sequence and functional analysis of cstB of Azospirillum brasilense Sp7. The predicted cstB contains C-terminal two PAS domains and N-terminal part which has similarity with CheB-CheR fusion protein. cstB mutants had reduced swarming ability compared to that of A. brasilense wild-type strain, implying that cstB was involved in chemotaxis in A. brasilense. A microscopic analysis revealed that cstB mutants developed mature cyst cells more quickly than wild type, indicating that cstB is involved in cyst formation. cstB mutants were affected in colony morphology and the production of exopolysaccharides (EPS) which are essential for A. brasilense cells to differentiate into cyst-like forms. These observations suggested that cstB was a multi-effector involved in cyst development and chemotaxis in A. brasilense. Copyright © 2010 Elsevier GmbH. All rights reserved.

Chemotaxis in densely populated tissue determines germinal center anatomy and cell motility: a new paradigm for the development of complex tissues.

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Jared B Hawkins

Full Text Available Germinal centers (GCs are complex dynamic structures that form within lymph nodes as an essential process in the humoral immune response. They represent a paradigm for studying the regulation of cell movement in the development of complex anatomical structures. We have developed a simulation of a modified cyclic re-entry model of GC dynamics which successfully employs chemotaxis to recapitulate the anatomy of the primary follicle and the development of a mature GC, including correctly structured mantle, dark and light zones. We then show that correct single cell movement dynamics (including persistent random walk and inter-zonal crossing arise from this simulation as purely emergent properties. The major insight of our study is that chemotaxis can only achieve this when constrained by the known biological properties that cells are incompressible, exist in a densely packed environment, and must therefore compete for space. It is this interplay of chemotaxis and competition for limited space that generates all the complex and biologically accurate behaviors described here. Thus, from a single simple mechanism that is well documented in the biological literature, we can explain both higher level structure and single cell movement behaviors. To our knowledge this is the first GC model that is able to recapitulate both correctly detailed anatomy and single cell movement. This mechanism may have wide application for modeling other biological systems where cells undergo complex patterns of movement to produce defined anatomical structures with sharp tissue boundaries.

Chemotaxis in densely populated tissue determines germinal center anatomy and cell motility: a new paradigm for the development of complex tissues.

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Hawkins, Jared B; Jones, Mark T; Plassmann, Paul E; Thorley-Lawson, David A

2011-01-01

Germinal centers (GCs) are complex dynamic structures that form within lymph nodes as an essential process in the humoral immune response. They represent a paradigm for studying the regulation of cell movement in the development of complex anatomical structures. We have developed a simulation of a modified cyclic re-entry model of GC dynamics which successfully employs chemotaxis to recapitulate the anatomy of the primary follicle and the development of a mature GC, including correctly structured mantle, dark and light zones. We then show that correct single cell movement dynamics (including persistent random walk and inter-zonal crossing) arise from this simulation as purely emergent properties. The major insight of our study is that chemotaxis can only achieve this when constrained by the known biological properties that cells are incompressible, exist in a densely packed environment, and must therefore compete for space. It is this interplay of chemotaxis and competition for limited space that generates all the complex and biologically accurate behaviors described here. Thus, from a single simple mechanism that is well documented in the biological literature, we can explain both higher level structure and single cell movement behaviors. To our knowledge this is the first GC model that is able to recapitulate both correctly detailed anatomy and single cell movement. This mechanism may have wide application for modeling other biological systems where cells undergo complex patterns of movement to produce defined anatomical structures with sharp tissue boundaries.

A monocyte chemotaxis inhibiting factor in serum of HIV infected men shares epitopes with the HIV transmembrane protein gp41

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Tas, M.; Drexhage, H. A.; Goudsmit, J.

1988-01-01

This report describes that gp41, the transmembranous envelope protein of HIV, is able to inhibit monocyte chemotaxis (measured as FMLP-induced polarization). To study the presence of such immunosuppressive HIV env proteins in the circulation of HIV-infected men, fractions were prepared from serum

Exponential signaling gain at the receptor level enhances signal-to-noise ratio in bacterial chemotaxis.

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Silke Neumann

Full Text Available Cellular signaling systems show astonishing precision in their response to external stimuli despite strong fluctuations in the molecular components that determine pathway activity. To control the effects of noise on signaling most efficiently, living cells employ compensatory mechanisms that reach from simple negative feedback loops to robustly designed signaling architectures. Here, we report on a novel control mechanism that allows living cells to keep precision in their signaling characteristics - stationary pathway output, response amplitude, and relaxation time - in the presence of strong intracellular perturbations. The concept relies on the surprising fact that for systems showing perfect adaptation an exponential signal amplification at the receptor level suffices to eliminate slowly varying multiplicative noise. To show this mechanism at work in living systems, we quantified the response dynamics of the E. coli chemotaxis network after genetically perturbing the information flux between upstream and downstream signaling components. We give strong evidence that this signaling system results in dynamic invariance of the activated response regulator against multiplicative intracellular noise. We further demonstrate that for environmental conditions, for which precision in chemosensing is crucial, the invariant response behavior results in highest chemotactic efficiency. Our results resolve several puzzling features of the chemotaxis pathway that are widely conserved across prokaryotes but so far could not be attributed any functional role.

In Entamoeba histolytica, a BspA family protein is required for chemotaxis toward tumour necrosis factor

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Anne Silvestre

2015-07-01

Full Text Available Background: Entamoeba histolytica cell migration is essential for the development of human amoebiasis (an infectious disease characterized by tissue invasion and destruction. The tissue inflammation associated with tumour necrosis factor (TNF secretion by host cells is a well-documented feature of amoebiasis. Tumour necrosis factor is a chemoattractant for E. histolytica, and the parasite may have a TNF receptor at its cell surface. Methods: confocal microscopy, RNA Sequencing, bioinformatics, RNA antisense techniques and histological analysis of human colon explants were used to characterize the interplay between TNF and E. histolytica. Results: an antibody against human TNF receptor 1 (TNFR1 stained the E. histolytica trophozoite surface and (on immunoblots binds to a 150-kDa protein. Proteome screening with the TNFR1 sequence revealed a BspA family protein in E. histolytica that carries a TNFR signature domain and six leucine-rich repeats (named here as "cell surface protein", CSP, in view of its cellular location. Cell surface protein shares structural homologies with Toll-Like receptors, colocalizes with TNF and is internalized in TNF-containing vesicles. Reduction of cellular CSP levels abolished chemotaxis toward TNF and blocked parasite invasion of human colon. Conclusions: there is a clear link between TNF chemotaxis, CSP and pathogenesis.

Criteria on global boundedness versus finite time blow-up to a two-species chemotaxis system with two chemicals

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Yu, Hao; Wang, Wei; Zheng, Sining

2018-02-01

This paper considers the two-species chemotaxis system with two chemicals in a smooth bounded domain Ω\\subset{R}2 , subject to the non-flux boundary condition, and χ, ξ, α, β, γ, δ>0 . We obtain a blow-up criterion that if m_1m_2-2π(\\frac{m_1}χβ+\\frac{m_2}ξδ)>0 , then there exist finite time blow-up solutions to the system with m_1:=\\int_Ω u_0(x)dx and m_2:=\\int_Ω w_0(x)dx . When χ=ξ= β=δ=1 , the blow-up criterion becomes m_1m_2-2π(m_1+m_2)>0 , and the global boundedness of solutions is furthermore established with α=γ=1 under the condition that \\max\\{m_1, m_2\\}4π and global boundedness with \\max\\{m_1, m_2\\}Funds for the Central Universities (DUT16LK24).

Dual acylation and lipid raft association of Src-family protein tyrosine kinases are required for SDF-1/CXCL12-mediated chemotaxis in the Jurkat human T cell lymphoma cell line.

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Zaman, Sabiha N; Resek, Mary E; Robbins, Stephen M

2008-10-01

Chemokines play pivotal roles in regulating a wide variety of biological processes by modulating cell migration and recruitment. Deregulation of chemokine signaling can alter cell recruitment, contributing to the pathogenic states associated with autoimmune disease, inflammatory disorders, and sepsis. During chemotaxis, lipid rafts and their resident signaling molecules have been demonstrated to partition to different parts of the cell. Herein, we investigated the role of lipid raft resident Src-family kinases (SFK) in stromal cell-derived factor 1/CXCL12-mediated chemotaxis. We have shown that Lck-deficient J.CaM 1.6 cells are defective in CXCL12-mediated chemotaxis in contrast to their parental counterpart, Jurkat cells. Ectopic expression of the SFK hematopoietic cell kinase (Hck) in J.CaM 1.6 cells reconstituted CXCL12 responsiveness. The requirement of lipid raft association of SFK was assessed using both isoforms of Hck: the dually acylated p59(Hck) isoform that is targeted to lipid rafts and the monoacylated p61(Hck) isoform that is nonraft-associated. We have shown using several gain and loss of acylation alleles that dual acylation of Hck was required for CXCL12-mediated chemotaxis in J.CaM 1.6 cells. These results highlight the importance of the unique microenvironment provided by lipid rafts and their specific contribution in providing specificity to CXCL12 signaling.

Mast cell chemotaxis – Chemoattractants and signaling pathways

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Ivana eHalova

2012-05-01

Full Text Available Migration of mast cells is essential for their recruitment within target tissues where they play an important role in innate and adaptive immune responses. These processes rely on the ability of mast cells to recognize appropriate chemotactic stimuli and react to them by a chemotactic response. Another level of intercellular communication is attained by production of chemoattractants by activated mast cells, which results in accumulation of mast cells and other hematopoietic cells at the sites of inflammation. Mast cells express numerous surface receptors for various ligands with properties of potent chemoattractants. They include the stem cell factor recognized by c-Kit, antigen, which binds to immunoglobulin E (IgE anchored to the high affinity IgE receptor (FcRI, highly cytokinergic IgE recognized by FcRI, lipid mediator sphingosine-1-phosphate (S1P, which binds to G-protein-coupled receptors (GPCRs. Other large groups of chemoattractants are eicosanoids [prostaglandin E2 and D2, leukotriene (LT B4, LTD4 and LTC4, and others] and chemokines (CC, CXC, C and CX3X, which also bind to various GPCRs. Further noteworthy chemoattractants are isoforms of transforming growth factor (TGF , which are sensitively recognized by TGF- serine/threonine type I and II  receptors, adenosine, C1q, C3a, and C5a components of the complement, 5-hydroxytryptamine, neuroendocrine peptide catestatin, interleukin-6, tumor necrosis factor- and others. Here we discuss the major types of chemoattractants recognized by mast cells, their target receptors, as well as signaling pathways they utilize. We also briefly deal with methods used for studies of mast cell chemotaxis and with ways of how these studies profited from the results obtained in other cellular systems.

CD147-mediated chemotaxis of CD4+CD161+ T cells may contribute to local inflammation in rheumatoid arthritis.

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Lv, Minghua; Miao, Jinlin; Zhao, Peng; Luo, Xing; Han, Qing; Wu, Zhenbiao; Zhang, Kui; Zhu, Ping

2018-01-01

CD161 is used as a surrogate marker for Th17 cells, which are implicated in the pathogenesis of rheumatoid arthritis (RA). In this study, we evaluated the percentage, clinical significance, and CD98 and CD147 expression of CD4 + CD161 + T cells. The potential role of CD147 and CD98 in cyclophilin A-induced chemotaxis of CD4 + CD161 + T cells was analyzed. Thirty-seven RA patients, 15 paired synovial fluid (SF) of RA, and 22 healthy controls were recruited. The cell populations and surface expression of CD98 and CD147 were analyzed by flow cytometry. Spearman's rank correlation coefficient and multiple linear regression were applied to calculate the correlations. Chemotaxis assay was used to investigate CD4 + CD161 + T cell migration. We found that the percentage of CD4 + CD161 + T cells and their expression of CD147 and CD98 in SF were higher than in the peripheral blood of RA patients. Percentage of SF CD4 + CD161 + T cells was positively correlated with 28-Joint Disease Activity Score (DAS28). CD147 monoclonal antibody (HAb18) attenuated the chemotactic ability of CD4 + CD161 + T cells. An increased CD4 + CD161 + T cell percentage and expression of CD147 and CD98 were shown in RA SF. Percentage of SF CD4 + CD161 + T cells can be used as a predictive marker of disease activity in RA. CD147 block significantly decreased the chemotactic index of CD4 + CD161 + cells induced by cyclophilin A (CypA). These results imply that the accumulation of CD4 + CD161 + T cells in SF and their high expression of CD147 may be associated with CypA-mediated chemotaxis and contribute to local inflammation in RA.

The Histone Deacetylase Inhibitors MS-275 and SAHA Suppress the p38 Mitogen-Activated Protein Kinase Signaling Pathway and Chemotaxis in Rheumatoid Arthritic Synovial Fibroblastic E11 Cells

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Hai-Shu Lin

2013-11-01

Full Text Available MS-275 (entinostat and SAHA (vorinostat, two histone deacetylase (HDAC inhibitors currently in oncological trials, have displayed potent anti-rheumatic activities in rodent models of rheumatoid arthritis (RA. To further elucidate their anti-inflammatory mechanisms, the impact of MS-275 and SAHA on the p38 mitogen-activated protein kinase (MAPK signaling pathway and chemotaxis was assessed in human rheumatoid arthritic synovial fibroblastic E11 cells. MS-275 and SAHA significantly suppressed the expression of p38α  MAPK, but induced the expression of MAPK phosphatase-1 (MKP-1, an endogenous suppressor of p38α  in E11 cells. At the same time, the association between p38α and MKP-1 was up-regulated and consequently, the activation (phosphorylation of p38α  was inhibited. Moreover, MS-275 and SAHA suppressed granulocyte chemotactic protein-2 (GCP-2, monocyte chemotactic protein-2 (MCP-2 and macrophage migration inhibitory factor (MIF in E11 cells in a concentration-dependent manner. Subsequently, E11-driven migration of THP-1 and U937 monocytes was inhibited. In summary, suppression of the p38 MAPK signaling pathway and chemotaxis appear to be important anti-rheumatic mechanisms of action of these HDAC inhibitors.

Crystallization and preliminary X-ray crystallographic analysis of CheW from Thermotoga maritima: a coupling protein of CheA and the chemotaxis receptor

International Nuclear Information System (INIS)

Park, SangYoun; Crane, Brian R.

2011-01-01

CheW from T. maritima has been crystallized (space group P6 3 , unit-cell parameters a = b = 61.265, c = 361.045 Å). Diffraction data have been collected to 3.1 Å resolution using synchrotron X-ray radiation. The CheW protein plays a key role in bacterial chemotaxis signal transduction by coupling CheA to chemotaxis receptors. CheW from Thermotoga maritima has been overexpressed in Escherichia coli and crystallized at 298 K using ammonium sulfate as a salt precipitant. X-ray diffraction data have been collected to 3.10 Å resolution at 100 K using synchrotron radiation. The crystal belonged to space group P6 3 , with unit-cell parameters a = b = 61.265, c = 361.045 Å. The asymmetric unit may contain four to six CheW molecules

The photosensor protein Ppr of Rhodocista centenaria is linked to the chemotaxis signalling pathway

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Kiefer Dorothee

2010-11-01

Full Text Available Abstract Background Rhodocista centenaria is a phototrophic α-proteobacterium exhibiting a phototactic behaviour visible as colony movement on agar plates directed to red light. As many phototrophic purple bacteria R. centenaria possesses a soluble photoactive yellow protein (Pyp. It exists as a long fusion protein, designated Ppr, consisting of three domains, the Pyp domain, a putative bilin binding domain (Bbd and a histidine kinase domain (Pph. The Ppr protein is involved in the regulation of polyketide synthesis but it is still unclear, how this is connected to phototaxis and chemotaxis. Results To elucidate the possible role of Ppr and Pph in the chemotactic network we studied the interaction with chemotactic proteins in vitro as well as in vivo. Matrix-assisted coelution experiments were performed to study the possible communication of the different putative binding partners. The kinase domain of the Ppr protein was found to interact with the chemotactic linker protein CheW. The formation of this complex was clearly ATP-dependent. Further results indicated that the Pph histidine kinase domain and CheW may form a complex with the chemotactic kinase CheAY suggesting a role of Ppr in the chemotaxis signalling pathway. In addition, when Ppr or Pph were expressed in Escherichia coli, the chemotactic response of the cells was dramatically affected. Conclusions The Ppr protein of Rhodocista centenaria directly interacts with the chemotactic protein CheW. This suggests a role of the Ppr protein in the regulation of the chemotactic response in addition to its role in chalcone synthesis.

Characterization of Spodoptera litura (Lepidoptera: Noctuidae) Takeout Genes and Their Differential Responses to Insecticides and Sex Pheromone

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Zhang, Ling; Jiang, Yanyun

2017-01-01

Abstract Spodoptera litura (S. litura) is one of the most serious agricultural insect pests worldwide. Takeout (TO) is involved in a variety of physiological and biochemical pathways and performs various biological functions. We characterized 18 S. litura TO genes and investigated their differential responses to insecticides and sex pheromones. All predicted TO proteins have two Cysteines that are unique to the N-terminal of the TO family proteins and contain four highly conserved Prolines, two Glycines, and one Tyrosine. The expression levels of seven TO genes in the male antennae were higher than those in the female antennae, although the expression levels of 10 TO genes in the female were higher than those in the male. We investigated the effects of the sex pheromone and three insecticides, that is, chlorpyrifos (Ch), emamectin benzoate (EB), and fipronil (Fi), on the expression levels of the TO genes in the antennae. The results showed that the insecticides and sex pheromone affect the expression levels of the TO genes. One day after the treatment, the expression levels of SlTO15 and SlTO4 were significantly induced by the Ch/EB treatment. Two days after the S. litura moths were treated with Fi, the expression of SlTO4 was significantly induced (28.35-fold). The expression of SlTO10 changed significantly after the Ch and EB treatment, although the expression of SlTO12 and SlTO15 was inhibited by the three insecticides after two days of treatment. Our results lay a foundation for studying the role of TO genes in the interaction between insecticides and sex pheromone. PMID:28973484

Genes2FANs: connecting genes through functional association networks

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2012-01-01

Background Protein-protein, cell signaling, metabolic, and transcriptional interaction networks are useful for identifying connections between lists of experimentally identified genes/proteins. However, besides physical or co-expression interactions there are many ways in which pairs of genes, or their protein products, can be associated. By systematically incorporating knowledge on shared properties of genes from diverse sources to build functional association networks (FANs), researchers may be able to identify additional functional interactions between groups of genes that are not readily apparent. Results Genes2FANs is a web based tool and a database that utilizes 14 carefully constructed FANs and a large-scale protein-protein interaction (PPI) network to build subnetworks that connect lists of human and mouse genes. The FANs are created from mammalian gene set libraries where mouse genes are converted to their human orthologs. The tool takes as input a list of human or mouse Entrez gene symbols to produce a subnetwork and a ranked list of intermediate genes that are used to connect the query input list. In addition, users can enter any PubMed search term and then the system automatically converts the returned results to gene lists using GeneRIF. This gene list is then used as input to generate a subnetwork from the user’s PubMed query. As a case study, we applied Genes2FANs to connect disease genes from 90 well-studied disorders. We find an inverse correlation between the counts of links connecting disease genes through PPI and links connecting diseases genes through FANs, separating diseases into two categories. Conclusions Genes2FANs is a useful tool for interpreting the relationships between gene/protein lists in the context of their various functions and networks. Combining functional association interactions with physical PPIs can be useful for revealing new biology and help form hypotheses for further experimentation. Our finding that disease genes in

A Circuit for Gradient Climbing in C. elegans Chemotaxis

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Johannes Larsch

2015-09-01

Full Text Available Animals have a remarkable ability to track dynamic sensory information. For example, the nematode Caenorhabditis elegans can locate a diacetyl odor source across a 100,000-fold concentration range. Here, we relate neuronal properties, circuit implementation, and behavioral strategies underlying this robust navigation. Diacetyl responses in AWA olfactory neurons are concentration and history dependent; AWA integrates over time at low odor concentrations, but as concentrations rise, it desensitizes rapidly through a process requiring cilia transport. After desensitization, AWA retains sensitivity to small odor increases. The downstream AIA interneuron amplifies weak odor inputs and desensitizes further, resulting in a stereotyped response to odor increases over three orders of magnitude. The AWA-AIA circuit drives asymmetric behavioral responses to odor increases that facilitate gradient climbing. The adaptation-based circuit motif embodied by AWA and AIA shares computational properties with bacterial chemotaxis and the vertebrate retina, each providing a solution for maintaining sensitivity across a dynamic range.

Data on functional characterization of LECT2 from Lampetra japonica

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Zhiliang Wang

2018-04-01

Full Text Available The data presented in this article are related to the research article entitled “Characterization of the LECT2 gene and its protective effects against microbial infection via large lymphocytes in Lampetra japonica” (Wang et al., 2017 [1]. Here, we presented new original data about the effect of rL-LECT2 on cancer cells migration and macrophages phagocytosis. Wound healing assay and transwell chemotaxis assays were used to measure rL-LECT2 inhibition rates on cancer cell migration. Additionally, fluospheres beads and Escherichia coli–FITC were used to measure whether the rL-LECT2 can affect the phagocytosis of RAW264.7 cells. Keywords: Lamprey, LECT2, Cell migration, Phagocytosis

In Vitro Global Gene Expression Analyses Support the Ethnopharmacological Use of Achyranthes aspera

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Pochi R. Subbarayan

2013-01-01

Full Text Available Achyranthes aspera (family Amaranthaceae is known for its anticancer properties. We have systematically validated the in vitro and in vivo anticancer properties of this plant. However, we do not know its mode of action. Global gene expression analyses may help decipher its mode of action. In the absence of identified active molecules, we believe this is the best approach to discover the mode of action of natural products with known medicinal properties. We exposed human pancreatic cancer cell line MiaPaCa-2 (CRL-1420 to 34 μg/mL of LE for 24, 48, and 72 hours. Gene expression analyses were performed using whole human genome microarrays (Agilent Technologies, USA. In our analyses, 82 (54/28 genes passed the quality control parameter, set at FDR ≤ 0.01 and FC of ≥±2. LE predominantly affected pathways of immune response, metabolism, development, gene expression regulation, cell adhesion, cystic fibrosis transmembrane conductance regulation (CFTR, and chemotaxis (MetaCore tool (Thomson Reuters, NY. Disease biomarker enrichment analysis identified LE regulated genes involved in Vasculitis—inflammation of blood vessels. Arthritis and pancreatitis are two of many etiologies for vasculitis. The outcome of disease network analysis supports the medicinal use of A. aspera, viz, to stop bleeding, as a cure for pancreatic cancer, as an antiarthritic medication, and so forth.

Cluster–cluster aggregation with particle replication and chemotaxy: a simple model for the growth of animal cells in culture

International Nuclear Information System (INIS)

Alves, S G; Martins, M L

2010-01-01

Aggregation of animal cells in culture comprises a series of motility, collision and adhesion processes of basic relevance for tissue engineering, bioseparations, oncology research and in vitro drug testing. In the present paper, a cluster–cluster aggregation model with stochastic particle replication and chemotactically driven motility is investigated as a model for the growth of animal cells in culture. The focus is on the scaling laws governing the aggregation kinetics. Our simulations reveal that in the absence of chemotaxy the mean cluster size and the total number of clusters scale in time as stretched exponentials dependent on the particle replication rate. Also, the dynamical cluster size distribution functions are represented by a scaling relation in which the scaling function involves a stretched exponential of the time. The introduction of chemoattraction among the particles leads to distribution functions decaying as power laws with exponents that decrease in time. The fractal dimensions and size distributions of the simulated clusters are qualitatively discussed in terms of those determined experimentally for several normal and tumoral cell lines growing in culture. It is shown that particle replication and chemotaxy account for the simplest cluster size distributions of cellular aggregates observed in culture

Multiple regulatory roles of the mouse transmembrane adaptor protein NTAL in gene transcription and mast cell physiology.

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Iva Polakovicova

Full Text Available Non-T cell activation linker (NTAL; also called LAB or LAT2 is a transmembrane adaptor protein that is expressed in a subset of hematopoietic cells, including mast cells. There are conflicting reports on the role of NTAL in the high affinity immunoglobulin E receptor (FcεRI signaling. Studies carried out on mast cells derived from mice with NTAL knock out (KO and wild type mice suggested that NTAL is a negative regulator of FcεRI signaling, while experiments with RNAi-mediated NTAL knockdown (KD in human mast cells and rat basophilic leukemia cells suggested its positive regulatory role. To determine whether different methodologies of NTAL ablation (KO vs KD have different physiological consequences, we compared under well defined conditions FcεRI-mediated signaling events in mouse bone marrow-derived mast cells (BMMCs with NTAL KO or KD. BMMCs with both NTAL KO and KD exhibited enhanced degranulation, calcium mobilization, chemotaxis, tyrosine phosphorylation of LAT and ERK, and depolymerization of filamentous actin. These data provide clear evidence that NTAL is a negative regulator of FcεRI activation events in murine BMMCs, independently of possible compensatory developmental alterations. To gain further insight into the role of NTAL in mast cells, we examined the transcriptome profiles of resting and antigen-activated NTAL KO, NTAL KD, and corresponding control BMMCs. Through this analysis we identified several genes that were differentially regulated in nonactivated and antigen-activated NTAL-deficient cells, when compared to the corresponding control cells. Some of the genes seem to be involved in regulation of cholesterol-dependent events in antigen-mediated chemotaxis. The combined data indicate multiple regulatory roles of NTAL in gene expression and mast cell physiology.

A PEG-DA microfluidic device for chemotaxis studies

International Nuclear Information System (INIS)

Traore, Mahama Aziz; Behkam, Bahareh

2013-01-01

The study of cells in a well-defined and chemically programmable microenvironment is essential for a complete and fundamental understanding of the cell behaviors with respect to specific chemical compounds. Flow-free microfluidic devices that generate quasi-steady chemical gradients (spatially varying but temporally constant) have been demonstrated as effective chemotaxis assay platforms due to dissociating the effect of chemical cues from mechanical shear forces caused by fluid flow. In this work, we demonstrate the fabrication and characterization of a flow-free microfluidic platform made of polyethylene glycol diacrylate (PEG-DA) hydrogel. We have demonstrated that the mass transport properties of these devices can be customized by fabricating them from PEG-DA gels of four distinct molecular weights. In contrast to microfluidic devices developed using soft lithography; this class of devices can be realized using a more cost-effective approach of direct photopolymerization with fewer microfabrication steps. This microfluidic platform was tested by conducting a quantitative study of the chemotactic behavior of Escherichia coli (E. coli) RP437, a model microorganism, in presence of the chemo-effector, casamino-acids. Using the microfabrication and characterization methodology presented in this work, microfluidic platforms with well-defined and customizable diffusive properties can be developed to accommodate the study of a wide range of cell types. (paper)

The stochastic dance of circling sperm cells: sperm chemotaxis in the plane

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Friedrich, B M; Juelicher, F [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)], E-mail: ben@pks.mpg.de, E-mail: julicher@pks.mpg.de

2008-12-15

Biological systems such as single cells must function in the presence of fluctuations. It has been shown in a two-dimensional experimental setup that sea urchin sperm cells move toward a source of chemoattractant along planar trochoidal swimming paths, i.e. drifting circles. In these experiments, a pronounced variability of the swimming paths is observed. We present a theoretical description of sperm chemotaxis in two dimensions which takes fluctuations into account. We derive a coarse-grained theory of stochastic sperm swimming paths in a concentration field of chemoattractant. Fluctuations enter as multiplicative noise in the equations for the sperm swimming path. We discuss the stochastic properties of sperm swimming and predict a concentration-dependence of the effective diffusion constant of sperm swimming which could be tested in experiments.

The stochastic dance of circling sperm cells: sperm chemotaxis in the plane

International Nuclear Information System (INIS)

Friedrich, B M; Juelicher, F

2008-01-01

Biological systems such as single cells must function in the presence of fluctuations. It has been shown in a two-dimensional experimental setup that sea urchin sperm cells move toward a source of chemoattractant along planar trochoidal swimming paths, i.e. drifting circles. In these experiments, a pronounced variability of the swimming paths is observed. We present a theoretical description of sperm chemotaxis in two dimensions which takes fluctuations into account. We derive a coarse-grained theory of stochastic sperm swimming paths in a concentration field of chemoattractant. Fluctuations enter as multiplicative noise in the equations for the sperm swimming path. We discuss the stochastic properties of sperm swimming and predict a concentration-dependence of the effective diffusion constant of sperm swimming which could be tested in experiments.

Collective Signal Processing in Cluster Chemotaxis: Roles of Adaptation, Amplification, and Co-attraction in Collective Guidance

Science.gov (United States)

Camley, Brian A.; Zimmermann, Juliane; Levine, Herbert; Rappel, Wouter-Jan

2016-01-01

Single eukaryotic cells commonly sense and follow chemical gradients, performing chemotaxis. Recent experiments and theories, however, show that even when single cells do not chemotax, clusters of cells may, if their interactions are regulated by the chemoattractant. We study this general mechanism of “collective guidance” computationally with models that integrate stochastic dynamics for individual cells with biochemical reactions within the cells, and diffusion of chemical signals between the cells. We show that if clusters of cells use the well-known local excitation, global inhibition (LEGI) mechanism to sense chemoattractant gradients, the speed of the cell cluster becomes non-monotonic in the cluster’s size—clusters either larger or smaller than an optimal size will have lower speed. We argue that the cell cluster speed is a crucial readout of how the cluster processes chemotactic signals; both amplification and adaptation will alter the behavior of cluster speed as a function of size. We also show that, contrary to the assumptions of earlier theories, collective guidance does not require persistent cell-cell contacts and strong short range adhesion. If cell-cell adhesion is absent, and the cluster cohesion is instead provided by a co-attraction mechanism, e.g. chemotaxis toward a secreted molecule, collective guidance may still function. However, new behaviors, such as cluster rotation, may also appear in this case. Co-attraction and adaptation allow for collective guidance that is robust to varying chemoattractant concentrations while not requiring strong cell-cell adhesion. PMID:27367541

Chemotaxis of primitive hematopoietic cells in response to stromal cell–derived factor-1

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Jo, Deog-Yeon; Rafii, Shahin; Hamada, Tsuneyoshi; Moore, Malcolm A.S.

2000-01-01

Stromal cell–derived factor-1 (SDF-1) provides a potent chemotactic stimulus for CD34+ hematopoietic cells. We cultured mobilized peripheral blood (PB) and umbilical cord blood (CB) for up to 5 weeks and examined the migratory activity of cobblestone area–forming cells (CAFCs) and long-term culture–initiating cells (LTC-ICs) in a transwell assay. In this system, SDF-1 or MS-5 marrow stromal cells placed in the lower chamber induced transmembrane and transendothelial migration by 2- and 5-week-old CAFCs and LTC-ICs in 3 hours. Transmigration was blocked by preincubation of input CD34+ cells with antibody to CXCR4. Transendothelial migration of CB CAFCs and LTC-ICs was higher than that of PB. We expanded CD34+ cells from CB in serum-free medium with thrombopoietin, flk-2 ligand, and c-kit ligand, with or without IL-3 and found that CAFCs cultured in the absence of IL-3 had a chemotactic response equivalent to noncultured cells, even after 5 weeks. However, addition of IL-3 to the culture reduced this response by 20–50%. These data indicate that SDF-1 induces chemotaxis of primitive hematopoietic cells signaling through CXCR4 and that the chemoattraction could be downmodulated by culture ex vivo. PMID:10619866

Global classical solvability and stabilization in a two-dimensional chemotaxis-Navier-Stokes system modeling coral fertilization

Science.gov (United States)

Espejo, Elio; Winkler, Michael

2018-04-01

The interplay of chemotaxis, convection and reaction terms is studied in the particular framework of a refined model for coral broadcast spawning, consisting of three equations describing the population densities of unfertilized sperms and eggs and the concentration of a chemical released by the latter, coupled to the incompressible Navier-Stokes equations. Under mild assumptions on the initial data, global existence of classical solutions to an associated initial-boundary value problem in bounded planar domains is established. Moreover, all these solutions are shown to approach a spatially homogeneous equilibrium in the large time limit.

Effects of undenatured whey protein supplementation on CXCL12- and CCL21-mediated B and T cell chemotaxis in diabetic mice

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Badr Gamal

2011-11-01

Full Text Available Abstract Background Long and persistent uncontrolled diabetes tends to degenerate the immune system and leads to an increased incidence of infection. Whey proteins (WPs enhance immunity during early life and have a protective role in some immune disorders. In this study, the effects of camel WP on the chemotaxis of B and T cells to CXCL12 and CCL21 in diabetic mice were investigated. Results Flow cytometric analysis of the surface expressions of CXCR4 (CXCL12 receptor and CCR7 (CCL21 receptor on B and T cells revealed that the surface expressions of CXCR4 and CCR7 were not significantly altered in diabetic and WP-supplemented diabetic mice compared with control mice. Nevertheless, B and T lymphocytes from diabetic mice were found to be in a stunned state, with a marked and significant (P Conclusion Our data revealed the benefits of WP supplementation in enhancing cytoskeletal rearrangement and chemotaxis in B and T cells, and subsequently improving the immune response in diabetic mice.

Neutrophil adhesion and chemotaxis depend on substrate mechanics

International Nuclear Information System (INIS)

Jannat, Risat A; Hammer, Daniel A; Robbins, Gregory P; Ricart, Brendon G; Dembo, Micah

2010-01-01

Neutrophil adhesion to the vasculature and chemotaxis within tissues play critical roles in the inflammatory response to injury and pathogens. Unregulated neutrophil activity has been implicated in the progression of numerous chronic and acute diseases such as rheumatoid arthritis, asthma and sepsis. Cell migration of anchorage-dependent cells is known to depend on both chemical and mechanical interactions. Although neutrophil responses to chemical cues have been well characterized, little is known about the effect of underlying tissue mechanics on neutrophil adhesion and migration. To address this question, we quantified neutrophil migration and traction stresses on compliant hydrogel substrates with varying elasticity in a micromachined gradient chamber in which we could apply either a uniform concentration or a precise gradient of the bacterial chemoattractant fMLP. Neutrophils spread more extensively on substrates of greater stiffness. In addition, increasing the stiffness of the substrate leads to a significant increase in the chemotactic index for each fMLP gradient tested. As the substrate becomes stiffer, neutrophils generate higher traction forces without significant changes in cell speed. These forces are often displayed in pairs and focused in the uropod. Increases in the mean fMLP concentration beyond the K D of the receptor lead to a decrease in chemotactic index on all surfaces. Blocking with an antibody against β 2 -integrins leads to a significant reduction, but not an elimination, of directed motility on stiff materials, but no change in motility on soft materials, suggesting neutrophils can display both integrin-dependent and integrin-independent motility. These findings are critical for understanding how neutrophil migration may change in different mechanical environments in vivo and can be used to guide the design of migration inhibitors that more efficiently target inflammation.

Neutrophil adhesion and chemotaxis depend on substrate mechanics

Energy Technology Data Exchange (ETDEWEB)

Jannat, Risat A; Hammer, Daniel A [Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 South 33rd Street, Philadelphia, PA 19104 (United States); Robbins, Gregory P; Ricart, Brendon G [Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 311A Towne Building, 220 South 33rd Street, Philadelphia, PA 19104 (United States); Dembo, Micah, E-mail: hammer@seas.upenn.ed [Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215 (United States)

2010-05-19

Neutrophil adhesion to the vasculature and chemotaxis within tissues play critical roles in the inflammatory response to injury and pathogens. Unregulated neutrophil activity has been implicated in the progression of numerous chronic and acute diseases such as rheumatoid arthritis, asthma and sepsis. Cell migration of anchorage-dependent cells is known to depend on both chemical and mechanical interactions. Although neutrophil responses to chemical cues have been well characterized, little is known about the effect of underlying tissue mechanics on neutrophil adhesion and migration. To address this question, we quantified neutrophil migration and traction stresses on compliant hydrogel substrates with varying elasticity in a micromachined gradient chamber in which we could apply either a uniform concentration or a precise gradient of the bacterial chemoattractant fMLP. Neutrophils spread more extensively on substrates of greater stiffness. In addition, increasing the stiffness of the substrate leads to a significant increase in the chemotactic index for each fMLP gradient tested. As the substrate becomes stiffer, neutrophils generate higher traction forces without significant changes in cell speed. These forces are often displayed in pairs and focused in the uropod. Increases in the mean fMLP concentration beyond the K{sub D} of the receptor lead to a decrease in chemotactic index on all surfaces. Blocking with an antibody against {beta}{sub 2}-integrins leads to a significant reduction, but not an elimination, of directed motility on stiff materials, but no change in motility on soft materials, suggesting neutrophils can display both integrin-dependent and integrin-independent motility. These findings are critical for understanding how neutrophil migration may change in different mechanical environments in vivo and can be used to guide the design of migration inhibitors that more efficiently target inflammation.

High fidelity information processing in folic acid chemotaxis of Dictyostelium amoebae.

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Segota, Igor; Mong, Surin; Neidich, Eitan; Rachakonda, Archana; Lussenhop, Catherine J; Franck, Carl

2013-11-06

Living cells depend upon the detection of chemical signals for their existence. Eukaryotic cells can sense a concentration difference as low as a few per cent across their bodies. This process was previously suggested to be limited by the receptor-ligand binding fluctuations. Here, we first determine the chemotaxis response of Dictyostelium cells to static folic acid gradients and show that they can significantly exceed this sensitivity, responding to gradients as shallow as 0.2% across the cell body. Second, using a previously developed information theory framework, we compare the total information gained about the gradient (based on the cell response) to its upper limit: the information gained at the receptor-ligand binding step. We find that the model originally applied to cAMP sensing fails as demonstrated by the violation of the data processing inequality, i.e. the total information exceeds the information at the receptor-ligand binding step. We propose an extended model with multiple known receptor types and with cells allowed to perform several independent measurements of receptor occupancy. This does not violate the data processing inequality and implies the receptor-ligand binding noise dominates both for low- and high-chemoattractant concentrations. We also speculate that the interplay between exploration and exploitation is used as a strategy for accurate sensing of otherwise unmeasurable levels of a chemoattractant.

Sphingomonas wittichii Strain RW1 Genome-Wide Gene Expression Shifts in Response to Dioxins and Clay.

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Benli Chai

Full Text Available Sphingomonas wittichii strain RW1 (RW1 is one of the few strains that can grow on dibenzo-p-dioxin (DD. We conducted a transcriptomic study of RW1 using RNA-Seq to outline transcriptional responses to DD, dibenzofuran (DF, and the smectite clay mineral saponite with succinate as carbon source. The ability to grow on DD is rare compared to growth on the chemically similar DF even though the same initial dioxygenase may be involved in oxidation of both substrates. Therefore, we hypothesized the reason for this lies beyond catabolic pathways and may concern genes involved in processes for cell-substrate interactions such as substrate recognition, transport, and detoxification. Compared to succinate (SUC as control carbon source, DF caused over 240 protein-coding genes to be differentially expressed, whereas more than 300 were differentially expressed with DD. Stress response genes were up-regulated in response to both DD and DF. This effect was stronger with DD than DF, suggesting a higher toxicity of DD compared to DF. Both DD and DF caused changes in expression of genes involved in active cross-membrane transport such as TonB-dependent receptor proteins, but the patterns of change differed between the two substrates. Multiple transcription factor genes also displayed expression patterns distinct to DD and DF growth. DD and DF induced the catechol ortho- and the salicylate/gentisate pathways, respectively. Both DD and DF induced the shared down-stream aliphatic intermediate compound pathway. Clay caused category-wide down-regulation of genes for cell motility and chemotaxis, particularly those involved in the synthesis, assembly and functioning of flagella. This is an environmentally important finding because clay is a major component of soil microbes' microenvironment influencing local chemistry and may serve as a geosorbent for toxic pollutants. Similar to clay, DD and DF also affected expression of genes involved in motility and chemotaxis.

Positive effects of repulsion on boundedness in a fully parabolic attraction-repulsion chemotaxis system with logistic source

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Wang, Wei; Zhuang, Mengdi; Zheng, Sining

2018-02-01

In this paper we study the global boundedness of solutions to the fully parabolic attraction-repulsion chemotaxis system with logistic source: ut = Δu - χ∇ ṡ (u∇v) + ξ∇ ṡ (u∇w) + f (u), vt = Δv - βv + αu, wt = Δw - δw + γu, subject to homogeneous Neumann boundary conditions in a bounded and smooth domain Ω ⊂Rn (n ≥ 1), where χ, α, ξ, γ, β and δ are positive constants, and f : R → R is a smooth function generalizing the logistic source f (s) = a - bsθ for all s ≥ 0 with a ≥ 0, b > 0 and θ ≥ 1. It is shown that when the repulsion cancels the attraction (i.e. χα = ξγ), the solution is globally bounded if n ≤ 3, or θ >θn : = min ⁡ {n+2}/4, n/√{n2 + 6 n + 17 }/-n2 - 3 n + 4 4 } with n ≥ 2. Therefore, due to the inhibition of repulsion to the attraction, in any spatial dimension, the exponent θ is allowed to take values less than 2 such that the solution is uniformly bounded in time.

The Regulation of Chemerin and CMKLR1 Genes Expression by TNF-α, Adiponectin, and Chemerin Analog in Bovine Differentiated Adipocytes

OpenAIRE

Y. Suzuki; Y. H. Hong; S. H. Song; A. Ardiyanti; D. Kato; K. H. So; K. Katoh; S. G Roh

2012-01-01

Adipokines, adipocyte-derived protein, have important roles in various kinds of physiology including energy homeostasis. Chemerin, one of adipocyte-derived adipokines, is highly expressed in differentiated adipocytes and is known to induce macrophage chemotaxis and glucose intolerance. The objective of the present study was to investigate the changes of chemerin and the chemokine-like-receptor 1 (CMKLR1) gene expression levels during differentiation of the bovine adipocyte and in differentiat...

Overexpression, purification, crystallization and preliminary X-ray analysis of CheY4 from Vibrio cholerae O395

International Nuclear Information System (INIS)

Biswas, Maitree; Khamrui, Susmita; Sen, Udayaditya; Dasgupta, Jhimli

2011-01-01

The chemotaxis response regulator CheY4 from V. cholerae has been cloned, overexpressed, purified and crystallized in monoclinic and hexagonal space groups; the crystals diffracted to 1.67 and 1.9 Å resolution, respectively. Chemotaxis and motility greatly influence the infectivity of Vibrio cholerae, although the role of chemotaxis genes in V. cholerae pathogenesis is poorly understood. In contrast to the single copy of CheY found in Escherichia coli and Salmonella typhimurium, four CheYs (CheY1–CheY4) are present in V. cholerae. While insertional disruption of the cheY4 gene results in decreased motility, insertional duplication of this gene increases motility and causes enhanced expression of the two major virulence genes. Additionally, cheY3/cheY4 influences the activation of the transcription factor NF-κB, which triggers the generation of acute inflammatory responses. V. cholerae CheY4 was cloned, overexpressed and purified by Ni–NTA affinity chromatography followed by gel filtration. Crystals of CheY4 grown in space group C2 diffracted to 1.67 Å resolution, with unit-cell parameters a = 94.4, b = 31.9, c = 32.6 Å, β = 96.5°, whereas crystals grown in space group P3 2 21 diffracted to 1.9 Å resolution, with unit-cell parameters a = b = 56.104, c = 72.283 Å, γ = 120°

Dynamic Response Genes in CD4+ T Cells Reveal a Network of Interactive Proteins that Classifies Disease Activity in Multiple Sclerosis

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Sandra Hellberg

2016-09-01

Full Text Available Multiple sclerosis (MS is a chronic inflammatory disease of the CNS and has a varying disease course as well as variable response to treatment. Biomarkers may therefore aid personalized treatment. We tested whether in vitro activation of MS patient-derived CD4+ T cells could reveal potential biomarkers. The dynamic gene expression response to activation was dysregulated in patient-derived CD4+ T cells. By integrating our findings with genome-wide association studies, we constructed a highly connected MS gene module, disclosing cell activation and chemotaxis as central components. Changes in several module genes were associated with differences in protein levels, which were measurable in cerebrospinal fluid and were used to classify patients from control individuals. In addition, these measurements could predict disease activity after 2 years and distinguish low and high responders to treatment in two additional, independent cohorts. While further validation is needed in larger cohorts prior to clinical implementation, we have uncovered a set of potentially promising biomarkers.

Bacillus subtilis Early Colonization of Arabidopsis thaliana Roots Involves Multiple Chemotaxis Receptors.

Science.gov (United States)

Allard-Massicotte, Rosalie; Tessier, Laurence; Lécuyer, Frédéric; Lakshmanan, Venkatachalam; Lucier, Jean-François; Garneau, Daniel; Caudwell, Larissa; Vlamakis, Hera; Bais, Harsh P; Beauregard, Pascale B

2016-11-29

Colonization of plant roots by Bacillus subtilis is mutually beneficial to plants and bacteria. Plants can secrete up to 30% of their fixed carbon via root exudates, thereby feeding the bacteria, and in return the associated B. subtilis bacteria provide the plant with many growth-promoting traits. Formation of a biofilm on the root by matrix-producing B. subtilis is a well-established requirement for long-term colonization. However, we observed that cells start forming a biofilm only several hours after motile cells first settle on the plant. We also found that intact chemotaxis machinery is required for early root colonization by B. subtilis and for plant protection. Arabidopsis thaliana root exudates attract B. subtilis in vitro, an activity mediated by the two characterized chemoreceptors, McpB and McpC, as well as by the orphan receptor TlpC. Nonetheless, bacteria lacking these chemoreceptors are still able to colonize the root, suggesting that other chemoreceptors might also play a role in this process. These observations suggest that A. thaliana actively recruits B. subtilis through root-secreted molecules, and our results stress the important roles of B. subtilis chemoreceptors for efficient colonization of plants in natural environments. These results demonstrate a remarkable strategy adapted by beneficial rhizobacteria to utilize carbon-rich root exudates, which may facilitate rhizobacterial colonization and a mutualistic association with the host. Bacillus subtilis is a plant growth-promoting rhizobacterium that establishes robust interactions with roots. Many studies have now demonstrated that biofilm formation is required for long-term colonization. However, we observed that motile B. subtilis mediates the first contact with the roots. These cells differentiate into biofilm-producing cells only several hours after the bacteria first contact the root. Our study reveals that intact chemotaxis machinery is required for the bacteria to reach the

Adaptation Mechanism of the Aspartate Receptor: Electrostatics of the Adaptation Subdomain Play a Key Role in Modulating Kinase Activity†

Science.gov (United States)

Starrett, Diane J.; Falke, Joseph J.

2010-01-01

substitutions (E308Q and E463Q) preserved normal kinase activation in vitro but blocked cellular chemotaxis in vivo, suggesting that these sites lie within the docking site of an adaptation enzyme, CheR or CheB. Overall, this study highlights the importance of electrostatics in signal transduction and regulation of kinase activity by the cytoplasmic domain of the aspartate receptor. PMID:15683239

Enzymes and Genes Involved in Aerobic Alkane Degradation

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Zongze eShao

2013-05-01

Full Text Available Alkanes are major constituents of crude oil. They are also present at low concentrations in diverse non-contaminated because many living organisms produce them as chemo-attractants or as protecting agents against water loss. Alkane degradation is a widespread phenomenon in nature. The numerous microorganisms, both prokaryotic and eukaryotic, capable of utilizing alkanes as a carbon and energy source, have been isolated and characterized. This review summarizes the current knowledge of how bacteria metabolize alkanes aerobically, with a particular emphasis on the oxidation of long-chain alkanes, including factors that are responsible for chemotaxis to alkanes , transport across cell membrane of alkanes , the regulation of alkane degradation gene and initial oxidation.

Lysophosphatidic acid induces chemotaxis in MC3T3-E1 osteoblastic cells

Energy Technology Data Exchange (ETDEWEB)

Masiello, Lisa M.; Fotos, Joseph S.; Galileo, Deni S.; Karin, Norm J.

2006-07-01

Lysophosphatidic acid (LPA) is a bioactive lipid that has pleiotropic effects on a variety of cell types and enhances the migration of endothelial and cancer cells, but it is not known if this lipid can alter osteoblast motility. We performed transwell migration assays using MC3T3-E1 osteoblastic cells and found LPA to be a potent chemotactic agent. Quantitative time-lapse video analysis of osteoblast migration after wounds were introduced into cell monolayers indicated that LPA stimulated both migration velocity and the average migration distance per cell. LPA also elicited substantial changes in cell shape and actin cytoskeletal structure; lipid-treated cells contained fewer stress fibers and displayed long membrane processes that were enriched in F-actin. Quantitative RT-PCR analysis showed that MC3T3-E1 cells express all four known LPA-specific G protein-coupled receptors (LPA1-LPA4) with a relative mRNA abundance of LPA1 > LPA4 > LPA2 >> LPA3. LPA-induced changes in osteoblast motility and morphology were antagonized by both pertussis toxin and Ki16425, a subtype-specific blocker of LPA1 and LPA3 receptor function. Cell migration in many cell types is linked to changes in intracellular Ca2+. Ki16425 also inhibited LPA-induced Ca2+ signaling in a dose-dependent manner, suggesting a link between LPA-induced Ca2+ transients and osteoblast chemotaxis. Our data show that LPA stimulates MC3T3-E1 osteoblast motility via a mechanism that is linked primarily to the G protein-coupled receptor LPA1.

Expression and contributions of the Kir2.1 inward-rectifier K+ channel to proliferation, migration and chemotaxis of microglia in unstimulated and anti-inflammatory states

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Doris eLam

2015-05-01

Full Text Available When microglia respond to CNS damage, they can range from pro-inflammatory (classical, M1 to anti-inflammatory, alternative (M2 and acquired deactivation states. It is important to determine how microglial functions are affected by these activation states, and to identify molecules that regulate their behavior. Microglial proliferation and migration are crucial during development and following damage in the adult, and both functions are Ca2+-dependent. In many cell types, the membrane potential and driving force for Ca2+ influx are regulated by inward-rectifier K+ channels, including Kir2.1, which is prevalent in microglia. However, it is not known whether Kir2.1 expression and contributions are altered in anti-inflammatory states. We tested the hypothesis that Kir2.1 contributes to Ca2+ entry, proliferation and migration of rat microglia. Kir2.1 (KCNJ2 transcript expression, current amplitude, and proliferation were comparable in unstimulated microglia and following alternative activation (IL-4 stimulated and acquired deactivation (IL-10 stimulated. To examine functional roles of Kir2.1 in microglia, we first determined that ML133 was more effective than the commonly used blocker, Ba2+; i.e., ML133 was potent (IC50=3.5 M and voltage independent. Both blockers slightly increased proliferation in unstimulated or IL-4 (but not IL-10-stimulated microglia. Stimulation with IL-4 or IL-10 increased migration and ATP-induced chemotaxis, and blocking Kir2.1 greatly reduced both but ML133 was more effective. In all three activation states, blocking Kir2.1 with ML133 dramatically reduced Ca2+ influx through Ca2+-release-activated Ca2+ (CRAC channels. Thus, Kir2.1 channel activity is necessary for microglial Ca2+ signaling and migration under resting and anti-inflammatory states but the channel weakly inhibits proliferation.

Chemotaxis and flow disorder shape microbial dispersion in porous media

Science.gov (United States)

De Anna, Pietro; Yawata, Yutaka; Stocker, Roman; Juanes, Ruben

2017-04-01

Bacteria drive a plethora of natural processes in the subsurface, consuming organic matter and catalysing chemical reactions that are key to global elemental cycles. These macro-scale consequences result from the collective action of individual bacteria at the micro-scale, which are modulated by the highly heterogeneous subsurface environment, dominated by flow disorder and strong chemical gradients. Yet, despite the generally recognized importance of these microscale processes, microbe-host medium interaction at the pore scale remain poorly characterized and understood. Here, we introduce a microfluidic model system to directly image and quantify the role of cell motility on bacterial dispersion and residence time in confined, porous, media. Using the soil-dwelling bacterium Bacillus subtilis and the common amino acid serine as a resource, we observe that chemotaxis in highly disordered and confined physico-chemical environment affords bacteria an increase in their ability to persistently occupy the host medium. Our findings illustrate that the interplay between bacterial behaviour and pore-scale disorder in fluid velocity and nutrient concentration directly impacts the residence time, transport and bio-geo-chemical transformation rates of biota in the subsurface, and thus likely the processes they mediate.

Philosophical conjectures and their refutation.

Science.gov (United States)

Kluge, A G

2001-06-01

Sir Karl Popper is well known for explicating science in falsificationist terms, for which his degree of corroboration formalism, C(h,e,b), has become little more than a symbol. For example, de Queiroz and Poe in this issue argue that C(h,e,b) reduces to a single relative (conditional) probability, p(e,hb), the likelihood of evidence e, given both hypothesis h and background knowledge b, and in reaching that conclusion, without stating or expressing it, they render Popper a verificationist. The contradiction they impose is easily explained--de Queiroz and Poe fail to take account of the fact that Popper derived C(h,e,b) from absolute (logical) probability and severity of test, S(e,h,b), where critical evidence, p(e,b), is fundamental. Thus, de Queiroz and Poe's conjecture that p(e,hb) = C(h,e,b) is refuted. Falsificationism, not verificationism, remains a fair description of the parsimony method of inference used in phylogenetic systematics, not withstanding de Queiroz and Poe's mistaken understanding that "statistical" probability justifies that method. Although de Queiroz and Poe assert that maximum likelihood has the power "to explain data", they do not successfully demonstrate how causal explanation is achieved or what it is that is being explained. This is not surprising, bearing in mind that what is assumed about character evolution in the accompanying likelihood model M cannot then be explained by the results of a maximum likelihood analysis.

Attachment, invasion, chemotaxis, and proteinase expression of B16-BL6 melanoma cells exhibiting a low metastatic phenotype after exposure to dietary restriction of tyrosine and phenylalanine.

Science.gov (United States)

Uhlenkott, C E; Huijzer, J C; Cardeiro, D J; Elstad, C A; Meadows, G G

1996-03-01

We previously reported that low levels of tyrosine (Tyr) and phenylalanine (Phe) alter the metastatic phenotype of B16-BL6 (BL6) murine melanoma and select for tumor cell populations with decreased lung colonizing ability. To more specifically characterize the effects of Tyr and Phe restriction on the malignant phenotype of BL6, we investigated in vitro attachment, invasion, proteinase expression, and chemotaxis of high and low metastatic BL6 variants. High metastatic variant cells were isolated from subcutaneous tumors of mice fed a nutritionally complete diet (ND cells) and low metastatic variant cells were isolated from mice fed a diet restricted in Tyr and Phe (LTP cells). Results indicate that attachment to reconstituted basement membrane (Matrigel) was significantly reduced in LTP cells as compared to ND cells. Attachment to collagen IV, laminin, and fibronectin were similar between the two variants. Invasion through Matrigel and growth factor-reduced Matrigel were significantly decreased in LTP cells as compared to ND cells. Zymography revealed the presence of M(r) 92,000 and M(r) 72,000 progelatinases, tissue plasminogen activator, and urokinase plasminogen activator in the conditioned medium of both variants; however, there were no differences in activity of these secreted proteinases between the two variants. Growth of the variants on growth factor-reduced Matrigel similarly induced expression of the M(r) 92,000 progelatinase. The variants exhibited similar chemotactic responses toward laminin. However, the chemotactic response toward fibronectin by LTP cells was significantly increased. MFR5, a monoclonal antibody which selectively blocks function of the alpha 5 chain of the alpha 5 beta 1 integrin, VLA-5, decreased the chemotactic response toward fibronectin of ND cells by 37%; the chemotactic response by LTP cells was reduced by 49%. This effect was specific for fibronectin-mediated chemotaxis since the chemotaxis toward laminin and invasion through

Characterization of Cell Surface and EPS Remodeling of Azospirillum brasilense Chemotaxis-like 1 Signal Transduction Pathway mutants by Atomic Force Microscopy

Energy Technology Data Exchange (ETDEWEB)

Billings, Amanda N [ORNL; Siuti, Piro [ORNL; Bible, Amber [University of Tennessee, Knoxville (UTK); Alexandre, Gladys [University of Tennessee, Knoxville (UTK); Retterer, Scott T [ORNL; Doktycz, Mitchel John [ORNL; Morrell-Falvey, Jennifer L [ORNL

2011-01-01

To compete in complex microbial communities, bacteria must quickly sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the modulation of multiple cellular responses, including motility, EPS production, and cell-to-cell interactions. Recently, the Che1 chemotaxis-like pathway from Azospirillum brasilense was shown to modulate flocculation. In A. brasilense, cell surface properties, including EPS production, are thought to play a direct role in promoting flocculation. Using atomic force microscopy (AFM), we have detected distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains that are absent in the wild type strain. Whereas the wild type strain produces a smooth mucosal extracellular matrix, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition and lectin-binding assays suggest that the composition of EPS components in the extracellular matrix differs between the cheA1 and cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that mutations in the Che1 pathway that result in increased flocculation are correlated with distinctive changes in the extracellular matrix structure produced by the mutants, including likely changes in the EPS structure and/or composition.

Identification of a novel gene in ROD9 island of Salmonella Enteritidis involved in the alteration of virulence-associated genes expression.

Science.gov (United States)

Das, Susmita; Ray, Shilpa; Ryan, Daniel; Sahu, Bikash; Suar, Mrutyunjay

2018-01-01

Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis), one of the causative agents for non-typhoidal gastrointestinal diseases in humans is an intracellular bacterium and mechanism for its invasion into host cells is critical to cause infection. The virulence of the pathogen is explained by the expression of genes located on its pathogenicity islands, mostly encoded under SPI-1 and SPI-2. However, S. Typhimurium SL1344, despite sharing ∼98% of its genome with S. Enteritidis P125109, lacks few regions of differences (ROD) that are hypothesized to impart virulence potential to S. Enteritidis. In this study, we created different mutants in the ROD9 island of S. Enteritidis, also referred as SPI-19 and identified a novel locus, SEN1005, encoding a hypothetical protein that is involved in its pathogenesis. ΔSEN1005 displayed significantly reduced entry into cultured epithelial cells as well as uptake by macrophages and failed to cause acute colitis in C57BL/6 mice at day 3 post-infection (p.i.). Additionally, the global transcriptome analysis revealed a highly repressed SPI-1 and other down-regulated genes responsible for flagellar assembly, chemotaxis and motility in the mutant which correlated with decreased invasion and abated inflammation as compared to the wild-type. Therefore, our findings revealed that ΔSEN1005 was attenuated in vitro as well as in vivo and we propose this hypothetical protein to play a role in altering the expression of genes involved in Salmonella virulence.

Leishmania amazonensis chemotaxis under glucose gradient studied by the strength and directionality of forces measured with optical tweezers

Science.gov (United States)

de Ysasa Pozzo, Liliana; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz Carlos; Ayres, Diana Copi; Giorgio, Selma; Cesar, Carlos Lenz

2007-02-01

Chemotaxis is the mechanism microorganisms use to sense the environment surrounding them and to direct their movement towards attractive, or away from the repellent, chemicals. The biochemical sensing is almost the only way for communication between unicellular organisms. Prokaryote and Eukaryote chemotaxis has been mechanically studied mainly by observing the directionality and timing of the microorganisms movements subjected to a chemical gradient, but not through the directionality and strength of the forces it generates. To observe the vector force of microorganisms under a chemical gradient we developed a system composed of two large chambers connected by a tiny duct capable to keep the chemical gradient constant for more than ten hours. We also used the displacements of a microsphere trapped in an Optical Tweezers as the force transducer to measure the direction and the strength of the propulsion forces of flagellum of the microorganism under several gradient conditions. A 9μm diameter microsphere particle was trapped with a Nd:YAG laser and its movement was measured through the light scattered focused on a quadrant detector. We observed the behavior of the protozoa Leishmania amazonensis (eukaryote) under several glucose gradients. This protozoa senses the gradient around it by swimming in circles for three to five times following by tumbling, and not by the typical straight swimming/tumbling of bacteria. Our results also suggest that force direction and strength are also used to control its movement, not only the timing of swimming/tumbling, because we observed a higher force strength clearly directed towards the glucose gradient.

The Regulation of Chemerin and CMKLR1 Genes Expression by TNF-α, Adiponectin, and Chemerin Analog in Bovine Differentiated Adipocytes

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Y. Suzuki

2012-09-01

Full Text Available Adipokines, adipocyte-derived protein, have important roles in various kinds of physiology including energy homeostasis. Chemerin, one of adipocyte-derived adipokines, is highly expressed in differentiated adipocytes and is known to induce macrophage chemotaxis and glucose intolerance. The objective of the present study was to investigate the changes of chemerin and the chemokine-like-receptor 1 (CMKLR1 gene expression levels during differentiation of the bovine adipocyte and in differentiated adipocytes treated with tumor necrosis factor-α (TNF-α, adiponectin, leptin, and chemerin (peptide analog. The expression levels of the chemerin gene increased at d 6 and 12 of the differentiation period accompanied by increased cytoplasm lipid droplets. From d 6 onward, peroxisome proliferator-activated receptor-γ2 (PPAR-γ2 gene expression levels were significantly higher than that of d 0 and 3. In contrast, CMKLR1 expression levels decreased at the end of the differentiation period. In fully differentiated adipocytes (i.e. at d 12, the treatment of TNF-α and adiponectin upregulated both chemerin and CMKLR1 gene expression levels, although leptin did not show such effects. Moreover, chemerin analog treatment was shown to upregulate chemerin gene expression levels regardless of doses. These results suggest that the expression of chemerin in bovine adipocyte might be regulated by chemerin itself and other adipokines, which indicates its possible role in modulating the adipokine secretions in adipose tissues.

Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Doktycz, Mitchel John [ORNL; Morrell-Falvey, Jennifer L [ORNL

2011-01-01

To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition.

Lysophosphatidic acid induces expression of genes in human oral keratinocytes involved in wound healing.

Science.gov (United States)

Thorlakson, Hong Huynh; Engen, Stian Andre; Schreurs, Olav; Schenck, Karl; Blix, Inger Johanne Schytte

2017-08-01

Epithelial cells participate in wound healing by covering wounds, but also as important mediators of wound healing processes. Topical application of the phospholipid growth factor lysophosphatidic acid (LPA) accelerates dermal wound healing and we hypothesized that LPA can play a role in human oral wound healing through its effects on human oral keratinocytes (HOK). HOK were isolated from gingival biopsies and exposed to LPA. The LPA receptor profile, signal transduction pathways, gene expression and secretion of selected cytokines were analyzed. HOK expressed the receptors LPA 1 , LPA 5 and LPA 6 and LPA activated the ERK1/2, JNK and p38 intracellular pathways, substantiated by secretion of IL-6 and IL-8. The early (2h) and intermediate (6h) gene expression profiles of HOK after LPA treatment showed a wide array of regulated genes. The majority of the strongest upregulated genes were related to chemotaxis and inflammation, and became downregulated after 6h. At 6h, genes coding for factors involved in extracellular matrix remodeling and re-epithelialization became highly expressed. IL-36γ, not earlier known to be regulated by LPA, was strongly transcribed and translated but not secreted. After stimulation with LPA, HOK responded by regulating factors and genes that are essential in wound healing processes. As LPA is found in saliva and is released by activated cells after wounding, our results indicate that LPA has a favorable physiological role in oral wound healing. This may further point towards a beneficial role for application of LPA on oral surgical or chronic wounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

PET/CT imaging of human somatostatin receptor 2 (hsstr2) as reporter gene for gene therapy

International Nuclear Information System (INIS)

Hofmann, M.; Gazdhar, A.; Weitzel, T.; Schmid, R.; Krause, T.

2006-01-01

Localized information on region-selective gene expression in small animals is widely obtained by use of reporter genes inducing light emission. Using these reporter genes for imaging deep inside the human body fluorescent probes are hindered by attenuation, scattering and possible fluorescence quenching. This can be overcome by use of radio-peptide receptors as reporter genes. Therefore, the feasibility of the somatostatin receptor 2 expression vector system for expression imaging was checked against a control vector containing luciferase gene. For in vivo transduction of vector DNA into the rat forelimb muscles the in vivo electroporation technique was chosen because of its high regio-selectivity. The gene expression was imaged by high-sensitive CCD camera (luciferase activity) and by PET/CT using a Ga-68-DOTATOC as radio peptide probe. The relative sstr2 expression was enhanced by gene transduction at maximum to a factor of 15. The PET/CT images could be fully quantified. The above demonstrated feasibility of radio-peptide PET/CT reporter gene imaging may serve in the future as a tool for full quantitative understanding of regional gene expression, especially in large animals and humans

PET/CT imaging of human somatostatin receptor 2 (hsstr2) as reporter gene for gene therapy

Energy Technology Data Exchange (ETDEWEB)

Hofmann, M. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland)]. E-mail: Michael.Hofmann@insel.ch; Gazdhar, A. [Division of Pulmonary Medicine, University Hospital Bern (Switzerland); Weitzel, T. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland); Schmid, R. [Division of Thoracic Surgery, University Hospital Bern (Switzerland); Krause, T. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland)

2006-12-20

Localized information on region-selective gene expression in small animals is widely obtained by use of reporter genes inducing light emission. Using these reporter genes for imaging deep inside the human body fluorescent probes are hindered by attenuation, scattering and possible fluorescence quenching. This can be overcome by use of radio-peptide receptors as reporter genes. Therefore, the feasibility of the somatostatin receptor 2 expression vector system for expression imaging was checked against a control vector containing luciferase gene. For in vivo transduction of vector DNA into the rat forelimb muscles the in vivo electroporation technique was chosen because of its high regio-selectivity. The gene expression was imaged by high-sensitive CCD camera (luciferase activity) and by PET/CT using a Ga-68-DOTATOC as radio peptide probe. The relative sstr2 expression was enhanced by gene transduction at maximum to a factor of 15. The PET/CT images could be fully quantified. The above demonstrated feasibility of radio-peptide PET/CT reporter gene imaging may serve in the future as a tool for full quantitative understanding of regional gene expression, especially in large animals and human000.

Adipose tissue gene expression analysis reveals changes in inflammatory, mitochondrial respiratory and lipid metabolic pathways in obese insulin-resistant subjects

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Soronen Jarkko

2012-04-01

Full Text Available Abstract Background To get insight into molecular mechanisms underlying insulin resistance, we compared acute in vivo effects of insulin on adipose tissue transcriptional profiles between obese insulin-resistant and lean insulin-sensitive women. Methods Subcutaneous adipose tissue biopsies were obtained before and after 3 and 6 hours of intravenously maintained euglycemic hyperinsulinemia from 9 insulin-resistant and 11 insulin-sensitive females. Gene expression was measured using Affymetrix HG U133 Plus 2 microarrays and qRT-PCR. Microarray data and pathway analyses were performed with Chipster v1.4.2 and by using in-house developed nonparametric pathway analysis software. Results The most prominent difference in gene expression of the insulin-resistant group during hyperinsulinemia was reduced transcription of nuclear genes involved in mitochondrial respiration (mitochondrial respiratory chain, GO:0001934. Inflammatory pathways with complement components (inflammatory response, GO:0006954 and cytokines (chemotaxis, GO:0042330 were strongly up-regulated in insulin-resistant as compared to insulin-sensitive subjects both before and during hyperinsulinemia. Furthermore, differences were observed in genes contributing to fatty acid, cholesterol and triglyceride metabolism (FATP2, ELOVL6, PNPLA3, SREBF1 and in genes involved in regulating lipolysis (ANGPTL4 between the insulin-resistant and -sensitive subjects especially during hyperinsulinemia. Conclusions The major finding of this study was lower expression of mitochondrial respiratory pathway and defective induction of lipid metabolism pathways by insulin in insulin-resistant subjects. Moreover, the study reveals several novel genes whose aberrant regulation is associated with the obese insulin-resistant phenotype.

Identification of distinct genes associated with seawater aspiration-induced acute lung injury by gene expression profile analysis

Science.gov (United States)

Liu, Wei; Pan, Lei; Zhang, Minlong; Bo, Liyan; Li, Congcong; Liu, Qingqing; Wang, Li; Jin, Faguang

2016-01-01

Seawater aspiration-induced acute lung injury (ALI) is a syndrome associated with a high mortality rate, which is characterized by severe hypoxemia, pulmonary edema and inflammation. The present study is the first, to the best of our knowledge, to analyze gene expression profiles from a rat model of seawater aspiration-induced ALI. Adult male Sprague-Dawley rats were instilled with seawater (4 ml/kg) in the seawater aspiration-induced ALI group (S group) or with distilled water (4 ml/kg) in the distilled water negative control group (D group). In the blank control group (C group) the rats' tracheae were exposed without instillation. Subsequently, lung samples were examined by histopathology; total protein concentration was detected in bronchoalveolar lavage fluid (BALF); lung wet/dry weight ratios were determined; and transcript expression was detected by gene sequencing analysis. The results demonstrated that histopathological alterations, pulmonary edema and total protein concentrations in BALF were increased in the S group compared with in the D group. Analysis of differential gene expression identified up and downregulated genes in the S group compared with in the D and C groups. A gene ontology analysis of the differential gene expression revealed enrichment of genes in the functional pathways associated with neutrophil chemotaxis, immune and defense responses, and cytokine activity. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the cytokine-cytokine receptor interaction pathway was one of the most important pathways involved in seawater aspiration-induced ALI. In conclusion, activation of the cytokine-cytokine receptor interaction pathway may have an essential role in the progression of seawater aspiration-induced ALI, and the downregulation of tumor necrosis factor superfamily member 10 may enhance inflammation. Furthermore, IL-6 may be considered a biomarker in seawater aspiration-induced ALI. PMID:27509884

Directional cell migration and chemotaxis in wound healing response to PDGF-AA are coordinated by the primary cilium in fibroblasts

DEFF Research Database (Denmark)

Schneider, Linda; Cammer, Michael; Lehman, Jonathan

2010-01-01

Cell motility and migration play pivotal roles in numerous physiological and pathophysiological processes including development and tissue repair. Cell migration is regulated through external stimuli such as platelet-derived growth factor-AA (PDGF-AA), a key regulator in directional cell migration....... Here we used micropipette analysis to show that a normal chemosensory response to PDGF-AA in fibroblasts requires the primary cilium. In vitro and in vivo wound healing assays revealed that in ORPK mouse (IFT88(Tg737Rpw)) fibroblasts, where ciliary assembly is defective, chemotaxis towards PDGF-AA...

Cloning, overexpression, purification, crystallization and preliminary X-ray analysis of CheY3, a response regulator that directly interacts with the flagellar ‘switch complex’ in Vibrio cholerae

International Nuclear Information System (INIS)

Khamrui, Susmita; Biswas, Maitree; Sen, Udayaditya; Dasgupta, Jhimli

2010-01-01

A chemotaxis response regulator CheY3 from V. cholerae has been cloned, overexpressed, purified and crystallized. The crystals of CheY3 diffracted to 1.86 Å resolution. Vibrio cholerae is the aetiological agent of the severe diarrhoeal disease cholera. This highly motile organism uses the processes of motility and chemotaxis to travel and colonize the intestinal epithelium. Chemotaxis in V. cholerae is far more complex than that in Escherichia coli or Salmonella typhimurium, with multiple paralogues of various chemotaxis genes. In contrast to the single copy of the chemotaxis response-regulator protein CheY in E. coli, V. cholerae contains four CheYs (CheY1–CheY4), of which CheY3 is primarily responsible for interacting with the flagellar motor protein FliM, which is one of the major constituents of the ‘switch complex’ in the flagellar motor. This interaction is the key step that controls flagellar rotation in response to environmental stimuli. CheY3 has been cloned, overexpressed and purified by Ni–NTA affinity chromatography followed by gel filtration. Crystals of CheY3 were grown in space group R3, with a calculated Matthews coefficient of 2.33 Å 3 Da −1 (47% solvent content) assuming the presence of one molecule per asymmetric unit

Monocyte chemotactic protein-3: possible involvement in apical periodontitis chemotaxis.

Science.gov (United States)

Dezerega, A; Osorio, C; Mardones, J; Mundi, V; Dutzan, N; Franco, M; Gamonal, J; Oyarzún, A; Overall, C M; Hernández, M

2010-10-01

To study the expression of monocyte chemotactic protein-3 (MCP-3, also known as chemokine CCL-7) in tissue from apical lesions (AL) and to associate MCP-3 expression with symptomatic or asymptomatic apical periodontitis. To determine the expression of MCP-3 in AL, biopsies obtained during tooth extraction procedures were fixed, subjected to routine processing and diagnosed as apical granuloma (AG) (n = 7) or radicular cyst (RC) (n = 5). As controls, apical periodontal ligament (PDL) specimens from healthy premolars extracted for orthodontics reasons were included (n = 7). All specimens were immunostained for MCP-3 and examined under a light microscope. In addition, homogenates from AL (n = 14) and healthy PDL samples (n = 7) were studied through immunowestern blot. Finally, periapical exudates samples were collected from root canals of teeth having diagnosis of symptomatic (n = 14) and asymptomatic apical periodontitis (n = 14) during routine endodontic treatments and analysed by immunowestern blot and densitometry.   MCP-3 was detected in AG and RC and localized mainly to inflammatory leucocytes, whereas no expression was observed in healthy PDLs. MCP-3 was also detected in periapical exudate, and its levels were significantly higher in symptomatic than in asymptomatic apical periodontitis. MCP-3 was expressed in AL and its levels associated with clinical symptoms. MCP-3 might play a role in disease pathogenesis, possibly by stimulating mononuclear chemotaxis. © 2010 International Endodontic Journal.

Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells

International Nuclear Information System (INIS)

Sarafian, Theodore; Montes, Cindy; Harui, Airi; Beedanagari, Sudheer R.; Kiertscher, Sylvia; Stripecke, Renata; Hossepian, Derik; Kitchen, Christina; Kern, Rita; Belperio, John; Roth, Michael D.

2008-01-01

Marijuana smoking is associated with a number of abnormal findings in the lungs of habitual smokers. Previous studies revealed that Δ 9 -tetrahydrocannabinol (THC) caused mitochondrial injury in primary lung epithelial cells and in the cell line, A549 [Sarafian, T. A., Kouyoumjian, S., Khoshaghideh, F., Tashkin, D. P., and Roth, M. D. (2003). Delta 9-tetrahydrocannabinol disrupts mitochondrial function and cell energetics. Am J Physiol Lung Cell Mol Physiol 284, L298-306; Sarafian, T., Habib, N., Mao, J. T., Tsu, I. H., Yamamoto, M. L., Hsu, E., Tashkin, D. P., and Roth, M. D. (2005). Gene expression changes in human small airway epithelial cells exposed to Delta9-tetrahydrocannabinol. Toxicol Lett 158, 95-107]. The role of cannabinoid receptors in this injury was unclear, as was the potential impact on cell function. In order to investigate these questions, A549 cells were engineered to over-express the type 2 cannabinoid receptor (CB2R) using a self-inactivating lentiviral vector. This transduction resulted in a 60-fold increase in CB2R mRNA relative to cells transduced with a control vector. Transduced cell lines were used to study the effects of THC on chemotactic activity and mitochondrial function. Chemotaxis in response to a 10% serum gradient was suppressed in a concentration-dependent manner by exposure to THC. CB2R-transduced cells exhibited less intrinsic chemotactic activity (p m ) in both control and CB2R-transduced cells. However, these decreases did not play a significant role in chemotaxis inhibition since cyclosporine A, which protected against ATP loss, did not increase cell migration. Moreover, CB2R-transduced cells displayed higher Ψ m than did control cells. Since both Ψ m and chemotaxis are regulated by intracellular signaling, we investigated the effects of THC on the activation of multiple signaling pathways. Serum exposure activated several signaling events of which phosphorylation of IκB-α and JNK was regulated in a CB2R- and THC

Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy.

Science.gov (United States)

Edwards, Amanda Nicole; Siuti, Piro; Bible, Amber N; Alexandre, Gladys; Retterer, Scott T; Doktycz, Mitchel J; Morrell-Falvey, Jennifer L

2011-01-01

To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition. FEMS Microbiology Letters © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original US government works.

Gene loss and horizontal gene transfer contributed to the genome evolution of the extreme acidophile Ferrovum

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Sophie Roxana Ullrich

2016-05-01

Full Text Available Acid mine drainage (AMD, associated with active and abandoned mining sites, is a habitat for acidophilic microorganisms that gain energy from the oxidation of reduced sulfur compounds and ferrous iron and that thrive at pH below 4. Members of the recently proposed genus Ferrovum are the first acidophilic iron oxidizers to be described within the Betaproteobacteria. Although they have been detected as typical community members in AMD habitats worldwide, knowledge of their phylogenetic and metabolic diversity is scarce. Genomics approaches appear to be most promising in addressing this lacuna since isolation and cultivation of Ferrovum has proven to be extremely difficult and has so far only been successful for the designated type strain Ferrovum myxofaciens P3G. In this study, the genomes of two novel strains of Ferrovum (PN-J185 and Z-31 derived from water samples of a mine water treatment plant were sequenced. These genomes were compared with those of Ferrovum sp. JA12 that also originated from the mine water treatment plant, and of the type strain (P3G. Phylogenomic scrutiny suggests that the four strains represent three Ferrovum species that cluster in two groups (1 and 2. Comprehensive analysis of their predicted metabolic pathways revealed that these groups harbor characteristic metabolic profiles, notably with respect to motility, chemotaxis, nitrogen metabolism, biofilm formation and their potential strategies to cope with the acidic environment. For example, while the F. myxofaciens strains (group 1 appear to be motile and diazotrophic, the non-motile group 2 strains have the predicted potential to use a greater variety of fixed nitrogen sources. Furthermore, analysis of their genome synteny provides first insights into their genome evolution, suggesting that horizontal gene transfer and genome reduction in the group 2 strains by loss of genes encoding complete metabolic pathways or physiological features contributed to the observed

Novel biallelic mutations in MSH6 and PMS2 genes: gene conversion as a likely cause of PMS2 gene inactivation.

Science.gov (United States)

Auclair, Jessie; Leroux, Dominique; Desseigne, Françoise; Lasset, Christine; Saurin, Jean Christophe; Joly, Marie Odile; Pinson, Stéphane; Xu, Xiao Li; Montmain, Gilles; Ruano, Eric; Navarro, Claudine; Puisieux, Alain; Wang, Qing

2007-11-01

Since the first report by our group in 1999, more than 20 unrelated biallelic mutations in DNA mismatch repair genes (MMR) have been identified. In the present report, we describe two novel cases: one carrying compound heterozygous mutations in the MSH6 gene; and the other, compound heterozygous mutations in the PMS2 gene. Interestingly, the inactivation of one PMS2 allele was likely caused by gene conversion. Although gene conversion has been suggested to be a mutation mechanism underlying PMS2 inactivation, this is the first report of its involvement in a pathogenic mutation. The clinical features of biallelic mutation carriers were similar to other previously described patients, with the presence of café-au-lait spots (CALS), early onset of brain tumors, and colorectal neoplasia. Our data provide further evidence of the existence, although rare, of a distinct recessively inherited syndrome on the basis of MMR constitutional inactivation. The identification of this syndrome should be useful for genetic counseling, especially in families with atypical hereditary nonpolyposis colon cancer (HNPCC) associated with childhood cancers, and for the clinical surveillance of these mutation carriers. 2007 Wiley-Liss, Inc.

Human amyloid β peptide and tau co-expression impairs behavior and causes specific gene expression changes in Caenorhabditis elegans.

Science.gov (United States)

Wang, Chenyin; Saar, Valeria; Leung, Ka Lai; Chen, Liang; Wong, Garry

2018-01-01

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the presence of extracellular amyloid plaques consisting of Amyloid-β peptide (Aβ) aggregates and neurofibrillary tangles formed by aggregation of hyperphosphorylated microtubule-associated protein tau. We generated a novel invertebrate model of AD by crossing Aβ1-42 (strain CL2355) with either pro-aggregating tau (strain BR5270) or anti-aggregating tau (strain BR5271) pan-neuronal expressing transgenic Caenorhabditis elegans. The lifespan and progeny viability of the double transgenic strains were significantly decreased compared with wild type N2 (P5E-21). RNA interference of 13 available top up-regulated genes in Aβ1-42+pro-aggregating tau animals revealed that F-box family genes and nep-4 could enhance life span deficits and chemotaxis deficits while Y39G8C.2 (TTBK2) could suppress these behaviors. Comparing the list of regulated genes from C. elegans to the top 60 genes related to human AD confirmed an overlap of 8 genes: patched homolog 1, PTCH1 (ptc-3), the Rab GTPase activating protein, TBC1D16 (tbc-16), the WD repeat and FYVE domain-containing protein 3, WDFY3 (wdfy-3), ADP-ribosylation factor guanine nucleotide exchange factor 2, ARFGEF2 (agef-1), Early B-cell Factor, EBF1 (unc-3), d-amino-acid oxidase, DAO (daao-1), glutamate receptor, metabotropic 1, GRM1 (mgl-2), prolyl 4-hydroxylase subunit alpha 2, P4HA2 (dpy-18 and phy-2). Taken together, our C. elegans double transgenic model provides insight on the fundamental neurobiologic processes underlying human AD and recapitulates selected transcriptomic changes observed in human AD brains. Copyright © 2017 Elsevier Inc. All rights reserved.

Systematic study of association of four GABAergic genes: glutamic acid decarboxylase 1 gene, glutamic acid decarboxylase 2 gene, GABA(B) receptor 1 gene and GABA(A) receptor subunit beta2 gene, with schizophrenia using a universal DNA microarray.

Science.gov (United States)

Zhao, Xu; Qin, Shengying; Shi, Yongyong; Zhang, Aiping; Zhang, Jing; Bian, Li; Wan, Chunling; Feng, Guoyin; Gu, Niufan; Zhang, Guangqi; He, Guang; He, Lin

2007-07-01

Several studies have suggested the dysfunction of the GABAergic system as a risk factor in the pathogenesis of schizophrenia. In the present study, case-control association analysis was conducted in four GABAergic genes: two glutamic acid decarboxylase genes (GAD1 and GAD2), a GABA(A) receptor subunit beta2 gene (GABRB2) and a GABA(B) receptor 1 gene (GABBR1). Using a universal DNA microarray procedure we genotyped a total of 20 SNPs on the above four genes in a study involving 292 patients and 286 controls of Chinese descent. Statistically significant differences were observed in the allelic frequencies of the rs187269C/T polymorphism in the GABRB2 gene (P=0.0450, chi(2)=12.40, OR=1.65) and the -292A/C polymorphism in the GAD1 gene (P=0.0450, chi(2)=14.64 OR=1.77). In addition, using an electrophoretic mobility shift assay (EMSA), we discovered differences in the U251 nuclear protein binding to oligonucleotides representing the -292 SNP on the GAD1 gene, which suggests that the -292C allele has reduced transcription factor binding efficiency compared with the 292A allele. Using the multifactor-dimensionality reduction method (MDR), we found that the interactions among the rs187269C/T polymorphism in the GABRB2 gene, the -243A/G polymorphism in the GAD2 gene and the 27379C/T and 661C/T polymorphisms in the GAD1 gene revealed a significant association with schizophrenia (Pschizophrenia in the Chinese population.

Aberrations of ERBB2 and TOP2A Genes in Breast Cancer

DEFF Research Database (Denmark)

Nielsen, Kirsten Vang; Müller, Sven; Møller, Susanne

2009-01-01

genes and the other by having amplification of ERBB2 and deletion of TOP2A. The characteristics are compared to findings on paired ERBB2 and TOP2A data from 649 patients with invasive breast cancer from a previously published biomarker study. The physical localization of FISH signals in metaphase...... spreads from cell lines showed that simultaneous amplification is not a simple co-amplification of a whole amplicon containing both genes. Most gene signals are translocated to abnormal marker chromosomes. ERBB2 genes but not TOP2A genes are present in tandem amplicons, leading to a higher ERBB2 ratio....... This observation was confirmed by patient FISH data: among 276 (43% of all patients) abnormal tumors, 67% had different ERBB2 and TOP2A status. ERBB2 amplification with normal TOP2A status was found in 36% of the abnormal tumors (15% of all patients). Simultaneous amplification of both genes was found in 28...

The structure and dynamic properties of the complete histidine phosphotransfer domain of the chemotaxis specific histidine autokinase CheA from Thermotoga maritima

International Nuclear Information System (INIS)

Vu, Anh; Hamel, Damon J.; Zhou Hongjun; Dahlquist, Frederick W.

2011-01-01

The bacterial histidine autokinase CheA contains a histidine phosphotransfer (Hpt) domain that accepts a phosphate from the catalytic domain and donates the phosphate to either target response regulator protein, CheY or CheB. The Hpt domain forms a helix-bundle structure with a conserved four-helix bundle motif and a variable fifth helix. Observation of two nearly equally populated conformations in the crystal structure of a Hpt domain fragment of CheA from Thermotoga maritima containing only the first four helices suggests more mobility in a tightly packed helix bundle structure than previously thought. In order to examine how the structures of Hpt domain homologs may differ from each other particularly in the conformation of the last helix, and whether an alternative conformation exists in the intact Hpt domain in solution, we have solved a high-resolution, solution structure of the CheA Hpt from T. maritima and characterized the backbone dynamics of this protein. The structure contains a four-helix bundle characteristic of histidine phosphotransfer domains. The position and orientation of the fifth helix resembles those in known Hpt domain crystal and solution structures in other histidine kinases. The alternative conformation that was reported in the crystal structure of the CheA Hpt from T. maritima missing the fifth helix is not detected in the solution structure, suggesting a role for the fifth helix in providing stabilizing forces to the overall structure.

Time-dependent gene expression analysis after mouse skeletal muscle contusion

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Weihua Xiao

2016-03-01

Conclusion: The sequence of immune cells invaded after muscle contusion was neutrophils, M1 macrophages and M2 macrophages. Some CC (CCL2, CCL3, and CCL4 and CXC (CXCL10 chemokines may be involved in the chemotaxis of these immune cells. HGF may be the primary factor to activate the satellite cells after muscle contusion. Moreover, 2 weeks are needed to recover when acute contusion happens as used in this study.

Induction of macrophage chemotaxis by aortic extracts from patients with Marfan syndrome is related to elastin binding protein.

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Gao Guo

Full Text Available Marfan syndrome is an autosomal dominantly inherited disorder of connective tissue with prominent skeletal, ocular, and cardiovascular manifestations. Aortic aneurysm and dissection are the major determinants of premature death in untreated patients. In previous work, we showed that extracts of aortic tissues from the mgR mouse model of Marfan syndrome showed increased chemotactic stimulatory activity related to the elastin-binding protein. Aortic samples were collected from 6 patients with Marfan syndrome and 8 with isolated aneurysms of the ascending aorta. Control samples were obtained from 11 organ donors without known vascular or connective tissue diseases. Soluble proteins extracted from the aortic samples of the two patient groups were compared against buffer controls and against the aortic samples from controls with respect to the ability to induce macrophage chemotaxis as measured using a modified Boyden chamber, as well as the reactivity to a monoclonal antibody BA4 against bioactive elastin peptides using ELISA. Samples from Marfan patients displayed a statistically significant increase in chemotactic inductive activity compared to control samples. Additionally, reactivity to BA4 was significantly increased. Similar statistically significant increases were identified for the samples from patients with idiopathic thoracic aortic aneurysm. There was a significant correlation between the chemotactic index and BA4 reactivity, and the increases in chemotactic activity of extracts from Marfan patients could be inhibited by pretreatment with lactose, VGVAPG peptides, or BA4, which indicates the involvement of EBP in mediating the effects. Our results demonstrate that aortic extracts of patients with Marfan syndrome can elicit macrophage chemotaxis, similar to our previous study on aortic extracts of the mgR mouse model of Marfan syndrome (Guo et al., Circulation 2006; 114:1855-62.

Induction of Macrophage Chemotaxis by Aortic Extracts from Patients with Marfan Syndrome Is Related to Elastin Binding Protein

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Guo, Gao; Gehle, Petra; Doelken, Sandra; Martin-Ventura, José Luis; von Kodolitsch, Yskert; Hetzer, Roland; Robinson, Peter N.

2011-01-01

Marfan syndrome is an autosomal dominantly inherited disorder of connective tissue with prominent skeletal, ocular, and cardiovascular manifestations. Aortic aneurysm and dissection are the major determinants of premature death in untreated patients. In previous work, we showed that extracts of aortic tissues from the mgR mouse model of Marfan syndrome showed increased chemotactic stimulatory activity related to the elastin-binding protein. Aortic samples were collected from 6 patients with Marfan syndrome and 8 with isolated aneurysms of the ascending aorta. Control samples were obtained from 11 organ donors without known vascular or connective tissue diseases. Soluble proteins extracted from the aortic samples of the two patient groups were compared against buffer controls and against the aortic samples from controls with respect to the ability to induce macrophage chemotaxis as measured using a modified Boyden chamber, as well as the reactivity to a monoclonal antibody BA4 against bioactive elastin peptides using ELISA. Samples from Marfan patients displayed a statistically significant increase in chemotactic inductive activity compared to control samples. Additionally, reactivity to BA4 was significantly increased. Similar statistically significant increases were identified for the samples from patients with idiopathic thoracic aortic aneurysm. There was a significant correlation between the chemotactic index and BA4 reactivity, and the increases in chemotactic activity of extracts from Marfan patients could be inhibited by pretreatment with lactose, VGVAPG peptides, or BA4, which indicates the involvement of EBP in mediating the effects. Our results demonstrate that aortic extracts of patients with Marfan syndrome can elicit macrophage chemotaxis, similar to our previous study on aortic extracts of the mgR mouse model of Marfan syndrome (Guo et al., Circulation 2006; 114:1855-62). PMID:21647416

Widespread ectopic expression of olfactory receptor genes

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Yanai Itai

2006-05-01

Full Text Available Abstract Background Olfactory receptors (ORs are the largest gene family in the human genome. Although they are expected to be expressed specifically in olfactory tissues, some ectopic expression has been reported, with special emphasis on sperm and testis. The present study systematically explores the expression patterns of OR genes in a large number of tissues and assesses the potential functional implication of such ectopic expression. Results We analyzed the expression of hundreds of human and mouse OR transcripts, via EST and microarray data, in several dozens of human and mouse tissues. Different tissues had specific, relatively small OR gene subsets which had particularly high expression levels. In testis, average expression was not particularly high, and very few highly expressed genes were found, none corresponding to ORs previously implicated in sperm chemotaxis. Higher expression levels were more common for genes with a non-OR genomic neighbor. Importantly, no correlation in expression levels was detected for human-mouse orthologous pairs. Also, no significant difference in expression levels was seen between intact and pseudogenized ORs, except for the pseudogenes of subfamily 7E which has undergone a human-specific expansion. Conclusion The OR superfamily as a whole, show widespread, locus-dependent and heterogeneous expression, in agreement with a neutral or near neutral evolutionary model for transcription control. These results cannot reject the possibility that small OR subsets might play functional roles in different tissues, however considerable care should be exerted when offering a functional interpretation for ectopic OR expression based only on transcription information.

Identification of conformational epitopes for human IgG on Chemotaxis inhibitory protein of Staphylococcus aureus

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Furebring Christina

2009-03-01

Full Text Available Abstract Background The Chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS blocks the Complement fragment C5a receptor (C5aR and formylated peptide receptor (FPR and is thereby a potent inhibitor of neutrophil chemotaxis and activation of inflammatory responses. The majority of the healthy human population has antibodies against CHIPS that have been shown to interfere with its function in vitro. The aim of this study was to define potential epitopes for human antibodies on the CHIPS surface. We also initiate the process to identify a mutated CHIPS molecule that is not efficiently recognized by preformed anti-CHIPS antibodies and retains anti-inflammatory activity. Results In this paper, we panned peptide displaying phage libraries against a pool of CHIPS specific affinity-purified polyclonal human IgG. The selected peptides could be divided into two groups of sequences. The first group was the most dominant with 36 of the 48 sequenced clones represented. Binding to human affinity-purified IgG was verified by ELISA for a selection of peptide sequences in phage format. For further analysis, one peptide was chemically synthesized and antibodies affinity-purified on this peptide were found to bind the CHIPS molecule as studied by ELISA and Surface Plasmon Resonance. Furthermore, seven potential conformational epitopes responsible for antibody recognition were identified by mapping phage selected peptide sequences on the CHIPS surface as defined in the NMR structure of the recombinant CHIPS31–121 protein. Mapped epitopes were verified by in vitro mutational analysis of the CHIPS molecule. Single mutations introduced in the proposed antibody epitopes were shown to decrease antibody binding to CHIPS. The biological function in terms of C5aR signaling was studied by flow cytometry. A few mutations were shown to affect this biological function as well as the antibody binding. Conclusion Conformational epitopes recognized by human antibodies

Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation

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Santanu Pailan

2015-11-01

Full Text Available An organophosphate (OP degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degraded within 96 h at 37 °C. Growth studies indicated the strain to be moderately thermo-halo tolerant in nature. Investigation based on identification of intermediates of parathion degradation by thin layer chromatography (TLC, high performance liquid chromatography (HPLC, gas chromatography (GC and liquid chromatography mass spectrometry (LC-MS/MS provided evidence for possible existence of two pathways. The first pathway proceeds via 4-nitrophenol (4-NP while the second proceeds through formation of 4-aminoparathion (4-APar, 4-aminophenol (4-AP and parabenzoquinone (PBQ. This is the first report of chemotaxis towards organophosphate compound by a thermo-halo tolerant bacterium.

Hydrogen Exchange Mass Spectrometry of Functional Membrane-bound Chemotaxis Receptor Complexes

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Koshy, Seena S.; Eyles, Stephen J.; Weis, Robert M.; Thompson, Lynmarie K.

2014-01-01

The transmembrane signaling mechanism of bacterial chemotaxis receptors is thought to involve changes in receptor conformation and dynamics. The receptors function in ternary complexes with two other proteins, CheA and CheW, that form extended membrane-bound arrays. Previous studies have shown that attractant binding induces a small (~2 Å) piston displacement of one helix of the periplasmic and transmembrane domains towards the cytoplasm, but it is not clear how this signal propagates through the cytoplasmic domain to control the kinase activity of the CheA bound at the membrane-distal tip, nearly 200 Å away. The cytoplasmic domain has been shown to be highly dynamic, which raises the question of how a small piston motion could propagate through a dynamic domain to control CheA kinase activity. To address this, we have developed a method for measuring dynamics of the receptor cytoplasmic fragment (CF) in functional complexes with CheA and CheW. Hydrogen exchange mass spectrometry (HDX-MS) measurements of global exchange of CF demonstrate that CF exhibits significantly slower exchange in functional complexes than in solution. Since the exchange rates in functional complexes are comparable to that of other proteins of similar structure, the CF appears to be a well-structured protein within these complexes, which is compatible with its role in propagating a signal that appears to be a tiny conformational change in the periplasmic and transmembrane domains of the receptor. We also demonstrate the feasibility of this protocol for local exchange measurements, by incorporating a pepsin digest step to produce peptides with 87% sequence coverage and only 20% back exchange. This method extends HDX-MS to membrane-bound functional complexes without detergents that may perturb the stability or structure of the system. PMID:24274333

Gene expression of the mismatch repair gene MSH2 in primary colorectal cancer

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Jensen, Lars Henrik; Kuramochi, Hidekazu; Crüger, Dorthe Gylling

2011-01-01

promoter was only detected in 14 samples and only at a low level with no correlation to gene expression. MSH2 gene expression was not a prognostic factor for overall survival in univariate or multivariate analysis. The gene expression of MSH2 is a potential quantitative marker ready for further clinical...

An agent-based model of signal transduction in bacterial chemotaxis.

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Jameson Miller

2010-05-01

Full Text Available We report the application of agent-based modeling to examine the signal transduction network and receptor arrays for chemotaxis in Escherichia coli, which are responsible for regulating swimming behavior in response to environmental stimuli. Agent-based modeling is a stochastic and bottom-up approach, where individual components of the modeled system are explicitly represented, and bulk properties emerge from their movement and interactions. We present the Chemoscape model: a collection of agents representing both fixed membrane-embedded and mobile cytoplasmic proteins, each governed by a set of rules representing knowledge or hypotheses about their function. When the agents were placed in a simulated cellular space and then allowed to move and interact stochastically, the model exhibited many properties similar to the biological system including adaptation, high signal gain, and wide dynamic range. We found the agent based modeling approach to be both powerful and intuitive for testing hypotheses about biological properties such as self-assembly, the non-linear dynamics that occur through cooperative protein interactions, and non-uniform distributions of proteins in the cell. We applied the model to explore the role of receptor type, geometry and cooperativity in the signal gain and dynamic range of the chemotactic response to environmental stimuli. The model provided substantial qualitative evidence that the dynamic range of chemotactic response can be traced to both the heterogeneity of receptor types present, and the modulation of their cooperativity by their methylation state.

An agent-based model of signal transduction in bacterial chemotaxis.

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Miller, Jameson; Parker, Miles; Bourret, Robert B; Giddings, Morgan C

2010-05-13

We report the application of agent-based modeling to examine the signal transduction network and receptor arrays for chemotaxis in Escherichia coli, which are responsible for regulating swimming behavior in response to environmental stimuli. Agent-based modeling is a stochastic and bottom-up approach, where individual components of the modeled system are explicitly represented, and bulk properties emerge from their movement and interactions. We present the Chemoscape model: a collection of agents representing both fixed membrane-embedded and mobile cytoplasmic proteins, each governed by a set of rules representing knowledge or hypotheses about their function. When the agents were placed in a simulated cellular space and then allowed to move and interact stochastically, the model exhibited many properties similar to the biological system including adaptation, high signal gain, and wide dynamic range. We found the agent based modeling approach to be both powerful and intuitive for testing hypotheses about biological properties such as self-assembly, the non-linear dynamics that occur through cooperative protein interactions, and non-uniform distributions of proteins in the cell. We applied the model to explore the role of receptor type, geometry and cooperativity in the signal gain and dynamic range of the chemotactic response to environmental stimuli. The model provided substantial qualitative evidence that the dynamic range of chemotactic response can be traced to both the heterogeneity of receptor types present, and the modulation of their cooperativity by their methylation state.

Genes2Networks: connecting lists of gene symbols using mammalian protein interactions databases

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Ma'ayan Avi

2007-10-01

Full Text Available Abstract Background In recent years, mammalian protein-protein interaction network databases have been developed. The interactions in these databases are either extracted manually from low-throughput experimental biomedical research literature, extracted automatically from literature using techniques such as natural language processing (NLP, generated experimentally using high-throughput methods such as yeast-2-hybrid screens, or interactions are predicted using an assortment of computational approaches. Genes or proteins identified as significantly changing in proteomic experiments, or identified as susceptibility disease genes in genomic studies, can be placed in the context of protein interaction networks in order to assign these genes and proteins to pathways and protein complexes. Results Genes2Networks is a software system that integrates the content of ten mammalian interaction network datasets. Filtering techniques to prune low-confidence interactions were implemented. Genes2Networks is delivered as a web-based service using AJAX. The system can be used to extract relevant subnetworks created from "seed" lists of human Entrez gene symbols. The output includes a dynamic linkable three color web-based network map, with a statistical analysis report that identifies significant intermediate nodes used to connect the seed list. Conclusion Genes2Networks is powerful web-based software that can help experimental biologists to interpret lists of genes and proteins such as those commonly produced through genomic and proteomic experiments, as well as lists of genes and proteins associated with disease processes. This system can be used to find relationships between genes and proteins from seed lists, and predict additional genes or proteins that may play key roles in common pathways or protein complexes.

Analysis of an ordered, comprehensive STM mutant library in infectious Borrelia burgdorferi: insights into the genes required for mouse infectivity.

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Tao Lin

Full Text Available The identification of genes important in the pathogenesis of Lyme disease Borrelia has been hampered by exceedingly low transformation rates in low-passage, infectious organisms. Using the infectious, moderately transformable B. burgdorferi derivative 5A18NP1 and signature-tagged versions of the Himar1 transposon vector pGKT, we have constructed a defined transposon library for the efficient genome-wide investigation of genes required for wild-type pathogenesis, in vitro growth, physiology, morphology, and plasmid replication. To facilitate analysis, the insertion sites of 4,479 transposon mutants were determined by sequencing. The transposon insertions were widely distributed across the entire B. burgdorferi genome, with an average of 2.68 unique insertion sites per kb DNA. The 10 linear plasmids and 9 circular plasmids had insertions in 33 to 100 percent of their predicted genes. In contrast, only 35% of genes in the 910 kb linear chromosome had incapacitating insertions; therefore, the remaining 601 chromosomal genes may represent essential gene candidates. In initial signature-tagged mutagenesis (STM analyses, 434 mutants were examined at multiple tissue sites for infectivity in mice using a semi-quantitative, Luminex-based DNA detection method. Examples of genes found to be important in mouse infectivity included those involved in motility, chemotaxis, the phosphoenolpyruvate phosphotransferase system, and other transporters, as well as putative plasmid maintenance genes. Availability of this ordered STM library and a high-throughput screening method is expected to lead to efficient assessment of the roles of B. burgdorferi genes in the infectious cycle and pathogenesis of Lyme disease.

Joint interpretation of geoelectrical and soil-gas measurements for monitoring CO2 releases at a natural analogue

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Sauer, U.; Watanabe, N.; Singh, Ashok

2014-01-01

the complex behaviour of temporal variations for the flow patterns. In particular, coupled migration of gas and water plays an important influencing role in this process. Site-specific, near surface geological features and meteorological conditions seem to exert great influence on the degassing pattern...... and flux measurements, self-potential (SP) and geoelectrical surveys) showed that the combination of geophysical methods with soil-gas analysis for mesoscale monitoring of the shallow subsurface above geologic CO2 storages can be a valuable tool for mapping and monitoring potential CO2 spread...... in the subsurface. Three measurement campaigns were undertaken - May 2011, July 2011 and April 2012 - at an analogue site in the Cheb Basin, Czech Republic, with the aim of studying CO2 leakages and their temporal and spatial behaviour. Results of geoelectrical investigations give an insight into the structural...

Using the 2A Protein Coexpression System: Multicistronic 2A Vectors Expressing Gene(s) of Interest and Reporter Proteins.

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Luke, Garry A; Ryan, Martin D

2018-01-01

To date, a huge range of different proteins-many with cotranslational and posttranslational subcellular localization signals-have been coexpressed together with various reporter proteins in vitro and in vivo using 2A peptides. The pros and cons of 2A co-expression technology are considered below, followed by a simple example of a "how to" protocol to concatenate multiple genes of interest, together with a reporter gene, into a single gene linked via 2As for easy identification or selection of transduced cells.

The Genome of Deep-Sea Vent Chemolithoautotroph Thiomicrospira crunogena XCL-2

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Scott, K M; Sievert, S M; Abril, F N; Ball, L A; Barrett, C J; Blake, R A; Boller, A J; Chain, P G; Clark, J A; Davis, C R; Detter, C; Do, K F; Dobrinski, K P; Faza, B I; Fitzpatrick, K A; Freyermuth, S K; Harmer, T L; Hauser, L J; Hugler, M; Kerfeld, C A; Klotz, M G; Kong, W W; Land, M; Lapidus, A; Larimer, F W; Longo, D L; Lucas, S; Malfatti, S A; Massey, S E; Martin, D D; McCuddin, Z; Meyer, F; Moore, J L; Ocampo Jr., L H; Paul, J H; Paulsen, I T; Reep, D K; Ren, Q; Ross, R L; Sato, P Y; Thomas, P; Tinkham, L E; Zerugh, G T

2007-01-10

Presented here is the complete genome sequence of Thiomicrospira crunogena XCL-2, representative of ubiquitous chemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-sea hydrothermal vents. This gammaproteobacterium has a single chromosome (2,427,734 bp), and its genome illustrates many of the adaptations that have enabled it to thrive at vents globally. It has 14 methyl-accepting chemotaxis protein genes, including four that may assist in positioning it in the redoxcline. A relative abundance of CDSs encoding regulatory proteins likely control the expression of genes encoding carboxysomes, multiple dissolved inorganic nitrogen and phosphate transporters, as well as a phosphonate operon, which provide this species with a variety of options for acquiring these substrates from the environment. T. crunogena XCL-2 is unusual among obligate sulfur oxidizing bacteria in relying on the Sox system for the oxidation of reduced sulfur compounds. A 38 kb prophage is present, and a high level of prophage induction was observed, which may play a role in keeping competing populations of close relatives in check. The genome has characteristics consistent with an obligately chemolithoautotrophic lifestyle, including few transporters predicted to have organic allocrits, and Calvin-Benson-Bassham cycle CDSs scattered throughout the genome.

Dendritic cell CNS recruitment correlates with disease severity in EAE via CCL2 chemotaxis at the blood–brain barrier through paracellular transmigration and ERK activation

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Sagar Divya

2012-10-01

Full Text Available Abstract Background Transmigration of circulating dendritic cells (DCs into the central nervous system (CNS across the blood–brain barrier (BBB has not thus far been investigated. An increase in immune cell infiltration across the BBB, uncontrolled activation and antigen presentation are influenced by chemokines. Chemokine ligand 2 (CCL2 is a potent chemoattractant known to be secreted by the BBB but has not been implicated in the recruitment of DCs specifically at the BBB. Methods Experimental autoimmune encephalomyelitis (EAE was induced in C57BL/6 mice by injection of MOG35–55 peptide and pertussis toxin intraperitoneally. Animals with increasing degree of EAE score were sacrificed and subjected to near-infrared and fluorescence imaging analysis to detect and localize the accumulation of CD11c+-labeled DCs with respect to CCL2 expression. To further characterize the direct effect of CCL2 in DC trafficking at the BBB, we utilized an in vitro BBB model consisting of human brain microvascular endothelial cells to compare migratory patterns of monocyte-derived dendritic cells, CD4+ and CD8+ T cells. Further, this model was used to image transmigration using fluorescence microcopy and to assess specific molecular signaling pathways involved in transmigration. Results Near-infrared imaging of DC transmigration correlated with the severity of inflammation during EAE. Ex vivo histology confirmed the presence of CCL2 in EAE lesions, with DCs emerging from perivascular spaces. DCs exhibited more efficient transmigration than T cells in BBB model studies. These observations correlated with transwell imaging, which indicated a paracellular versus transcellular pattern of migration by DCs and T cells. Moreover, at the molecular level, CCL2 seems to facilitate DC transmigration in an ERK1/2-dependent manner. Conclusion CNS recruitment of DCs correlates with disease severity in EAE via CCL2 chemotaxis and paracellular transmigration across the BBB

Pretreatment with Fish Oil-Based Lipid Emulsion Modulates Muscle Leukocyte Chemotaxis in Murine Model of Sublethal Lower Limb Ischemia

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Yao-Ming Shih

2017-01-01

Full Text Available This study investigated the effects of a fish oil- (FO- based lipid emulsion on muscle leukocyte chemotaxis and inflammatory responses in a murine model of limb ischemia-reperfusion (IR injury. Mice were assigned randomly to 1 sham (sham group, 2 ischemic groups, and 2 IR groups. The sham group did not undergo the ischemic procedure. The mice assigned to the ischemic or IR groups were pretreated intraperitoneally with either saline or FO-based lipid emulsion for 3 consecutive days. The IR procedure was induced by applying a 4.5 oz orthodontic rubber band to the left thigh above the greater trochanter for 120 min and then cutting the band to allow reperfusion. The ischemic groups were sacrificed immediately while the IR groups were sacrificed 24 h after reperfusion. Blood, IR-injured gastrocnemius, and lung tissues were collected for analysis. The results showed that FO pretreatment suppressed the local and systemic expression of several IR-induced proinflammatory mediators. Also, the FO-pretreated group had lower blood Ly6ChiCCR2hi monocyte percentage and muscle M1/M2 ratio than the saline group at 24 h after reperfusion. These findings suggest that FO pretreatment may have a protective role in limb IR injury by modulating the expression of proinflammatory mediators and regulating the polarization of macrophage.

Gene2Function: An Integrated Online Resource for Gene Function Discovery

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Yanhui Hu

2017-08-01

Full Text Available One of the most powerful ways to develop hypotheses regarding the biological functions of conserved genes in a given species, such as humans, is to first look at what is known about their function in another species. Model organism databases and other resources are rich with functional information but difficult to mine. Gene2Function addresses a broad need by integrating information about conserved genes in a single online resource.

CDX2 gene expression in acute lymphoblastic leukemia

International Nuclear Information System (INIS)

Arnaoaut, H.H.; Mokhtar, D.A.; Samy, R.M.; Omar, Sh.A.; Khames, S.A.

2014-01-01

CDX genes are classically known as regulators of axial elongation during early embryogenesis. An unsuspected role for CDX genes has been revealed during hematopoietic development. The CDX gene family member CDX2 belongs to the most frequent aberrantly expressed proto-oncogenes in human acute leukemias and is highly leukemogenic in experimental models. We used reversed transcriptase polymerase chain reaction (RT-PCR) to determine the expression level of CDX2 gene in 30 pediatric patients with acute lymphoblastic leukemia (ALL) at diagnosis and 30 healthy volunteers. ALL patients were followed up to detect minimal residual disease (MRD) on days 15 and 42 of induction. We found that CDX2 gene was expressed in 50% of patients and not expressed in controls. Associations between gene expression and different clinical and laboratory data of patients revealed no impact on different findings. With follow up, we could not confirm that CDX2 expression had a prognostic significance.

Gene duplications in prokaryotes can be associated with environmental adaptation.

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Bratlie, Marit S; Johansen, Jostein; Sherman, Brad T; Huang, Da Wei; Lempicki, Richard A; Drabløs, Finn

2010-10-20

Gene duplication is a normal evolutionary process. If there is no selective advantage in keeping the duplicated gene, it is usually reduced to a pseudogene and disappears from the genome. However, some paralogs are retained. These gene products are likely to be beneficial to the organism, e.g. in adaptation to new environmental conditions. The aim of our analysis is to investigate the properties of paralog-forming genes in prokaryotes, and to analyse the role of these retained paralogs by relating gene properties to life style of the corresponding prokaryotes. Paralogs were identified in a number of prokaryotes, and these paralogs were compared to singletons of persistent orthologs based on functional classification. This showed that the paralogs were associated with for example energy production, cell motility, ion transport, and defence mechanisms. A statistical overrepresentation analysis of gene and protein annotations was based on paralogs of the 200 prokaryotes with the highest fraction of paralog-forming genes. Biclustering of overrepresented gene ontology terms versus species was used to identify clusters of properties associated with clusters of species. The clusters were classified using similarity scores on properties and species to identify interesting clusters, and a subset of clusters were analysed by comparison to literature data. This analysis showed that paralogs often are associated with properties that are important for survival and proliferation of the specific organisms. This includes processes like ion transport, locomotion, chemotaxis and photosynthesis. However, the analysis also showed that the gene ontology terms sometimes were too general, imprecise or even misleading for automatic analysis. Properties described by gene ontology terms identified in the overrepresentation analysis are often consistent with individual prokaryote lifestyles and are likely to give a competitive advantage to the organism. Paralogs and singletons dominate

Thermo-Regulation of Genes Mediating Motility and Plant Interactions in Pseudomonas syringae

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Hockett, Kevin L.; Burch, Adrien Y.; Lindow, Steven E.

2013-01-01

Pseudomonas syringae is an important phyllosphere colonist that utilizes flagellum-mediated motility both as a means to explore leaf surfaces, as well as to invade into leaf interiors, where it survives as a pathogen. We found that multiple forms of flagellum-mediated motility are thermo-suppressed, including swarming and swimming motility. Suppression of swarming motility occurs between 28° and 30°C, which coincides with the optimal growth temperature of P. syringae. Both fliC (encoding flagellin) and syfA (encoding a non-ribosomal peptide synthetase involved in syringafactin biosynthesis) were suppressed with increasing temperature. RNA-seq revealed 1440 genes of the P. syringae genome are temperature sensitive in expression. Genes involved in polysaccharide synthesis and regulation, phage and IS elements, type VI secretion, chemosensing and chemotaxis, translation, flagellar synthesis and motility, and phytotoxin synthesis and transport were generally repressed at 30°C, while genes involved in transcriptional regulation, quaternary ammonium compound metabolism and transport, chaperone/heat shock proteins, and hypothetical genes were generally induced at 30°C. Deletion of flgM, a key regulator in the transition from class III to class IV gene expression, led to elevated and constitutive expression of fliC regardless of temperature, but did not affect thermo-regulation of syfA. This work highlights the importance of temperature in the biology of P. syringae, as many genes encoding traits important for plant-microbe interactions were thermo-regulated. PMID:23527276

Cross-talk between Tetraspanin CD9 and Transmembrane Adaptor Protein Non-T Cell Activation Linker (NTAL) in Mast Cell Activation and Chemotaxis

Czech Academy of Sciences Publication Activity Database

Hálová, Ivana; Dráberová, Lubica; Bambousková, Monika; Machyna, Martin; Stegurová, Lucie; Smrž, Daniel; Dráber, Petr

2013-01-01

Roč. 288, č. 14 (2013), s. 9801-9814 ISSN 0021-9258 R&D Projects: GA ČR GA301/09/1826; GA ČR GAP302/10/1759; GA ČR(CZ) GBP302/12/G101; GA ČR(CZ) GD204/09/H084; GA MŠk LD12073; GA TA ČR TA01010436; GA MPO FR-TI3/067 Grant - others:European Cooperation in Science and Technology(XE) Action BM1007 Institutional support: RVO:68378050 Keywords : mast cell * chemotaxis * Fc receptor Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.600, year: 2013

Differential gene expression profiling of mouse skin after sulfur mustard exposure: Extended time response and inhibitor effect

International Nuclear Information System (INIS)

Gerecke, Donald R.; Chen Minjun; Isukapalli, Sastry S.; Gordon, Marion K.; Chang, Y.-C.; Tong Weida; Androulakis, Ioannis P.; Georgopoulos, Panos G.

2009-01-01

Sulfur mustard (HD, SM), is a chemical warfare agent that within hours causes extensive blistering at the dermal-epidermal junction of skin. To better understand the progression of SM-induced blistering, gene expression profiling for mouse skin was performed after a single high dose of SM exposure. Punch biopsies of mouse ears were collected at both early and late time periods following SM exposure (previous studies only considered early time periods). The biopsies were examined for pathological disturbances and the samples further assayed for gene expression profiling using the Affymetrix microarray analysis system. Principal component analysis and hierarchical cluster analysis of the differently expressed genes, performed with ArrayTrack showed clear separation of the various groups. Pathway analysis employing the KEGG library and Ingenuity Pathway Analysis (IPA) indicated that cytokine-cytokine receptor interaction, cell adhesion molecules (CAMs), and hematopoietic cell lineage are common pathways affected at different time points. Gene ontology analysis identified the most significantly altered biological processes as the immune response, inflammatory response, and chemotaxis; these findings are consistent with other reported results for shorter time periods. Selected genes were chosen for RT-PCR verification and showed correlations in the general trends for the microarrays. Interleukin 1 beta was checked for biological analysis to confirm the presence of protein correlated to the corresponding microarray data. The impact of a matrix metalloproteinase inhibitor, MMP-2/MMP-9 inhibitor I, against SM exposure was assessed. These results can help in understanding the molecular mechanism of SM-induced blistering, as well as to test the efficacy of different inhibitors

A space-jump derivation for non-local models of cell-cell adhesion and non-local chemotaxis.

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Buttenschön, Andreas; Hillen, Thomas; Gerisch, Alf; Painter, Kevin J

2018-01-01

Cellular adhesion provides one of the fundamental forms of biological interaction between cells and their surroundings, yet the continuum modelling of cellular adhesion has remained mathematically challenging. In 2006, Armstrong et al. proposed a mathematical model in the form of an integro-partial differential equation. Although successful in applications, a derivation from an underlying stochastic random walk has remained elusive. In this work we develop a framework by which non-local models can be derived from a space-jump process. We show how the notions of motility and a cell polarization vector can be naturally included. With this derivation we are able to include microscopic biological properties into the model. We show that particular choices yield the original Armstrong model, while others lead to more general models, including a doubly non-local adhesion model and non-local chemotaxis models. Finally, we use random walk simulations to confirm that the corresponding continuum model represents the mean field behaviour of the stochastic random walk.

miR-24-2 controls H2AFX expression regardless of gene copy number alteration and induces apoptosis by targeting antiapoptotic gene BCL-2: a potential for therapeutic intervention.

Science.gov (United States)

Srivastava, Niloo; Manvati, Siddharth; Srivastava, Archita; Pal, Ranjana; Kalaiarasan, Ponnusamy; Chattopadhyay, Shilpi; Gochhait, Sailesh; Dua, Raina; Bamezai, Rameshwar N K

2011-04-04

New levels of gene regulation with microRNA (miR) and gene copy number alterations (CNAs) have been identified as playing a role in various cancers. We have previously reported that sporadic breast cancer tissues exhibit significant alteration in H2AX gene copy number. However, how CNA affects gene expression and what is the role of miR, miR-24-2, known to regulate H2AX expression, in the background of the change in copy number, are not known. Further, many miRs, including miR-24-2, are implicated as playing a role in cell proliferation and apoptosis, but their specific target genes and the pathways contributing to them remain unexplored. Changes in gene copy number and mRNA/miR expression were estimated using real-time polymerase chain reaction assays in two mammalian cell lines, MCF-7 and HeLa, and in a set of sporadic breast cancer tissues. In silico analysis was performed to find the putative target for miR-24-2. MCF-7 cells were transfected with precursor miR-24-2 oligonucleotides, and the gene expression levels of BRCA1, BRCA2, ATM, MDM2, TP53, CHEK2, CYT-C, BCL-2, H2AFX and P21 were examined using TaqMan gene expression assays. Apoptosis was measured by flow cytometric detection using annexin V dye. A luciferase assay was performed to confirm BCL-2 as a valid cellular target of miR-24-2. It was observed that H2AX gene expression was negatively correlated with miR-24-2 expression and not in accordance with the gene copy number status, both in cell lines and in sporadic breast tumor tissues. Further, the cells overexpressing miR-24-2 were observed to be hypersensitive to DNA damaging drugs, undergoing apoptotic cell death, suggesting the potentiating effect of mir-24-2-mediated apoptotic induction in human cancer cell lines treated with anticancer drugs. BCL-2 was identified as a novel cellular target of miR-24-2. mir-24-2 is capable of inducing apoptosis by modulating different apoptotic pathways and targeting BCL-2, an antiapoptotic gene. The study suggests

Investigating the association of chemokine receptor 5 (CCR5 polymorphism with cervical cancer in human papillomavirus (HPV positive patients - DOI: 10.4025/actascihealthsci.v30i2.944 Investigating association of chemokine receptor 5 (CCR5 polymorphism with cervical cancer in human papillomavirus (HPV suggestive patients - DOI: 10.4025/actascihealthsci.v30i2.944

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Sueli Donizete Borelli

2008-12-01

Full Text Available HPV is one of the most frequent causes for the development of cervical cancer. It is known that chemokines are important determinants of early inflammatory responses. The CC chemokine receptor 5 (CCR5 gene is involved in the chemotaxis of leukocytes toward inflammation sites. In the present study, polymerase chain reactions (PCR in genomic DNA samples, using specific CCR5 oligonucleotide primers surrounding the breakpoint deletion, detected a 225 bp product from the normal CCR5 allele and a 193 bp product from the 32 bp deletion allele. The wild type genotype was prevalent in both group, but it was not statistically significant, with χ2 = 1.519 (2 degrees of freedom; p > 0.05. As there are a small number of 32 allele carriers, further studies are needed to clarify the role of CCR5 in the cervical cancer.HPV is the most responsible of cervical cancer. It is known that chemokines are important determinants of the early inflammatory response. The CC chemokine receptor 5 (CCR5 gene is involved in the chemotaxis of leukocytes toward inflammation sites. In the present study, polymerase chain reactions (PCR in genomic DNA samples, using specific CCR5 oligonucleotide primers surrounding the breakpoint deletion, detected a 225bp product from the normal CCR5 allele and a 193bp product from the 32bp deletion allele. The wild type genotype was prevalent in both group, but it wasn’t statistically significant with χ² =1,519 (2 degrees of freedom; p>0.05. Once there is a small number of 32 allele carriers, further studies are needed to clarify the role of CCR5 in the cervical cancer.

Gene duplication, silencing and expression alteration govern the molecular evolution of PRC2 genes in plants.

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Furihata, Hazuka Y; Suenaga, Kazuya; Kawanabe, Takahiro; Yoshida, Takanori; Kawabe, Akira

2016-10-13

PRC2 genes were analyzed for their number of gene duplications, d N /d S ratios and expression patterns among Brassicaceae and Gramineae species. Although both amino acid sequences and copy number of the PRC2 genes were generally well conserved in both Brassicaceae and Gramineae species, we observed that some rapidly evolving genes experienced duplications and expression pattern changes. After multiple duplication events, all but one or two of the duplicated copies tend to be silenced. Silenced copies were reactivated in the endosperm and showed ectopic expression in developing seeds. The results indicated that rapid evolution of some PRC2 genes is initially caused by a relaxation of selective constraint following the gene duplication events. Several loci could become maternally expressed imprinted genes and acquired functional roles in the endosperm.

Azorhizobium caulinodans Transmembrane Chemoreceptor TlpA1 Involved in Host Colonization and Nodulation on Roots and Stems

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Wei Liu

2017-07-01

Full Text Available Azorhizobium caulinodans ORS571 is a motile soil bacterium that interacts symbiotically with legume host Sesbania rostrata, forming nitrogen-fixing root and stem nodules. Bacterial chemotaxis plays an important role in establishing this symbiotic relationship. To determine the contribution of chemotaxis to symbiosis in A. caulinodans ORS571-S. rostrata, we characterized the function of TlpA1 (transducer-like protein in A. caulinodans, a chemoreceptor predicted by SMART (Simple Modular Architecture Research Tool, containing two N-terminal transmembrane regions. The tlpA1 gene is located immediately upstream of the unique che gene cluster and is transcriptionally co-oriented. We found that a ΔtlpA1 mutant is severely impaired for chemotaxis to various organic acids, glycerol and proline. Furthermore, biofilm forming ability of the strain carrying the mutation is reduced under certain growth conditions. Interestingly, competitive colonization ability on S. rostrata root surfaces is impaired in the ΔtlpA1 mutant, suggesting that chemotaxis of the A. caulinodans ORS571 contributes to root colonization. We also found that TlpA1 promotes competitive nodulation not only on roots but also on stems of S. rostrata. Taken together, our data strongly suggest that TlpA1 is a transmembrane chemoreceptor involved in A. caulinodans-S. rostrata symbiosis.

Differential gene expression by integrin β7+ and β7- memory T helper cells

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Yang Yee

2004-07-01

Full Text Available Abstract Background The cell adhesion molecule integrin α4β7 helps direct the migration of blood lymphocytes to the intestine and associated lymphoid tissues. We hypothesized that β7+ and β7- blood memory T helper cells differ in their expression of genes that play a role in the adhesion or migration of T cells. Results RNA was prepared from β7+ and β7- CD4+ CD45RA- blood T cells from nine normal human subjects and analyzed using oligonucleotide microarrays. Of 21357 genes represented on the arrays, 16 were more highly expressed in β7+ cells and 18 were more highly expressed in β7- cells (≥1.5 fold difference and adjusted P + memory/effector T cells than on β7- cells. Conclusions Memory/effector T cells that express integrin β7 have a distinct pattern of expression of a set of gene transcripts. Several of these molecules can affect cell adhesion or chemotaxis and are therefore likely to modulate the complex multistep process that regulates trafficking of CD4+ memory T cell subsets with different homing behaviors.

Complex epigenetic regulation of engrailed-2 (EN-2) homeobox gene in the autism cerebellum.

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James, S J; Shpyleva, Svitlana; Melnyk, Stepan; Pavliv, Oleksandra; Pogribny, I P

2013-02-19

The elucidation of epigenetic alterations in the autism brain has potential to provide new insights into the molecular mechanisms underlying abnormal gene expression in this disorder. Given strong evidence that engrailed-2 (EN-2) is a developmentally expressed gene relevant to cerebellar abnormalities and autism, the epigenetic evaluation of this candidate gene was undertaken in 26 case and control post-mortem cerebellar samples. Assessments included global DNA methylation, EN-2 promoter methylation, EN-2 gene expression and EN-2 protein levels. Chromatin immunoprecipitation was used to evaluate trimethylation status of histone H3 lysine 27 (H3K27) associated with gene downregulation and histone H3 lysine 4 (H3K4) associated with gene activation. The results revealed an unusual pattern of global and EN-2 promoter region DNA hypermethylation accompanied by significant increases in EN-2 gene expression and protein levels. Consistent with EN-2 overexpression, histone H3K27 trimethylation mark in the EN-2 promoter was significantly decreased in the autism samples relative to matched controls. Supporting a link between reduced histone H3K27 trimethylation and increased EN-2 gene expression, the mean level of histone H3K4 trimethylation was elevated in the autism cerebellar samples. Together, these results suggest that the normal EN-2 downregulation that signals Purkinje cell maturation during late prenatal and early-postnatal development may not have occurred in some individuals with autism and that the postnatal persistence of EN-2 overexpression may contribute to autism cerebellar abnormalities.

A Single Dose of LSD Does Not Alter Gene Expression of the Serotonin 2A Receptor Gene (HTR2A) or Early Growth Response Genes (EGR1-3) in Healthy Subjects

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Dolder, Patrick C.; Grünblatt, Edna; Müller, Felix; Borgwardt, Stefan J.; Liechti, Matthias E.

2017-01-01

Rationale: Renewed interest has been seen in the use of lysergic acid diethylamide (LSD) in psychiatric research and practice. The repeated use of LSD leads to tolerance that is believed to result from serotonin (5-HT) 5-HT2A receptor downregulation. In rats, daily LSD administration for 4 days decreased frontal cortex 5-HT2A receptor binding. Additionally, a single dose of LSD acutely increased expression of the early growth response genes EGR1 and EGR2 in rat and mouse brains through 5-HT2A receptor stimulation. No human data on the effects of LSD on gene expression has been reported. Therefore, we investigated the effects of single-dose LSD administration on the expression of the 5-HT2A receptor gene (HTR2A) and EGR1-3 genes. Methods: mRNA expression levels were analyzed in whole blood as a peripheral biomarker in 15 healthy subjects before and 1.5 and 24 h after the administration of LSD (100 μg) and placebo in a randomized, double-blind, placebo-controlled, cross-over study. Results: LSD did not alter the expression of the HTR2A or EGR1-3 genes 1.5 and 24 h after administration compared with placebo. Conclusion: No changes were observed in the gene expression of LSD’s primary target receptor gene or genes that are implicated in its downstream effects. Remaining unclear is whether chronic LSD administration alters gene expression in humans. PMID:28701958

Mapping of novel powdery mildew resistance gene(s) from Agropyron cristatum chromosome 2P.

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Li, Huanhuan; Jiang, Bo; Wang, Jingchang; Lu, Yuqing; Zhang, Jinpeng; Pan, Cuili; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

2017-01-01

A physical map of Agropyron cristatum 2P chromosome was constructed for the first time and the novel powdery mildew resistance gene(s) from chromosome 2P was(were) also mapped. Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), a wild relative of common wheat, is highly resistant to powdery mildew. Previous studies showed that wheat-A. cristatum 2P disomic addition line II-9-3 displayed high resistance to powdery mildew, and the resistance was attributable to A. cristatum chromosome 2P. To utilize and physically map the powdery mildew resistance gene(s), 15 wheat-A. cristatum 2P translocation lines and three A. cristatum 2P deletion lines with different chromosomal segment sizes, obtained from II-9-3 using 60 Co-γ ray irradiation, were characterized using cytogenetic and molecular marker analysis. A. cristatum 2P chromosomal segments in the translocations were translocated to different wheat chromosomes, including 1A, 4A, 5A, 6A, 7A, 1B, 2B, 3B, 7B, 3D, 4D, and 6D. A physical map of the 2P chromosome was constructed with 82 STS markers, consisting of nine bins with 34 markers on 2PS and eight bins with 48 markers on 2PL. The BC 1 F 2 populations of seven wheat-A. cristatum 2P translocation lines (2PT-3, 2PT-4, 2PT-5, 2PT-6, 2PT-8, 2PT-9, and 2PT-10) were developed by self-pollination, tested with powdery mildew and genotyped with 2P-specific STS markers. From these results, the gene(s) conferring powdery mildew resistance was(were) located on 2PL bin FL 0.66-0.86 and 19 2P-specific markers were identified in this bin. Moreover, two new powdery mildew-resistant translocation lines (2PT-4 and 2PT-5) with small 2PL chromosome segments were obtained. The newly developed wheat lines with powdery mildew resistance and the closely linked molecular markers will be valuable for wheat disease breeding in the future.

Sphingosine-1-Phosphate Induces Dose-Dependent Chemotaxis or Fugetaxis of T-ALL Blasts through S1P1 Activation

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Messias, Carolina V.; Santana-Van-Vliet, Eliane; Lemos, Julia P.; Moreira, Otacilio C.; Cotta-de-Almeida, Vinicius; Savino, Wilson; Mendes-da-Cruz, Daniella Arêas

2016-01-01

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5). S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL) did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM) did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000–10000 nM) through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts. PMID:26824863

Sphingosine-1-Phosphate Induces Dose-Dependent Chemotaxis or Fugetaxis of T-ALL Blasts through S1P1 Activation.

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Carolina V Messias

Full Text Available Sphingosine-1-phosphate (S1P is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5. S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000-10000 nM through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts.

Molecular and Functional Characterization of Broccoli EMBRYONIC FLOWER 2 Genes

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Chen, Long-Fang O.; Lin, Chun-Hung; Lai, Ying-Mi; Huang, Jia-Yuan; Sung, Zinmay Renee

2012-01-01

Polycomb group (PcG) proteins regulate major developmental processes in Arabidopsis. EMBRYONIC FLOWER 2 (EMF2), the VEFS domain-containing PcG gene, regulates diverse genetic pathways and is required for vegetative development and plant survival. Despite widespread EMF2-like sequences in plants, little is known about their function other than in Arabidopsis and rice. To study the role of EMF2 in broccoli (Brassica oleracea var. italica cv. Elegance) development, we identified two broccoli EMF2 (BoEMF2) genes with sequence homology to and a similar gene expression pattern to that in Arabidopsis (AtEMF2). Reducing their expression in broccoli resulted in aberrant phenotypes and gene expression patterns. BoEMF2 regulates genes involved in diverse developmental and stress programs similar to AtEMF2 in Arabidopsis. However, BoEMF2 differs from AtEMF2 in the regulation of flower organ identity, cell proliferation and elongation, and death-related genes, which may explain the distinct phenotypes. The expression of BoEMF2.1 in the Arabidopsis emf2 mutant (Rescued emf2) partially rescued the mutant phenotype and restored the gene expression pattern to that of the wild type. Many EMF2-mediated molecular and developmental functions are conserved in broccoli and Arabidopsis. Furthermore, the restored gene expression pattern in Rescued emf2 provides insights into the molecular basis of PcG-mediated growth and development. PMID:22537758

Identification and characterization of human GUKH2 gene in silico.

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Katoh, Masuko; Katoh, Masaru

2004-04-01

Drosophila Guanylate-kinase holder (Gukh) is an adaptor molecule bridging Discs large (Dlg) and Scribble (Scrib), which are implicated in the establishment and maintenance of epithelial polarity. Here, we searched for human homologs of Drosophila gukh by using bioinformatics, and identified GUKH1 and GUKH2 genes. GUKH1 was identical to Nance-Horan syndrome (NHS) gene, while GUKH2 was a novel gene. FLJ35425 (AK092744.1), DKFZp686P1949 (BX647246.1) and KIAA1357 (AB037778.1) cDNAs were derived from human GUKH2 gene. Nucleotide sequence of GUKH2 cDNA was determined by assembling 5'-part of FLJ35425 cDNA and entire region of DKFZp686P1949 cDNA. Human GUKH2 gene consists of 8 exons. Exon 5 (132 bp) of GUKH2 gene was spliced out in GUKH2 cDNA due to alternative splicing. GUKH2-REPS1 locus at human chromosome 6q24.1 and GUKH1-REPS2 locus at human chromosome Xp22.22-p22.13 are paralogous regions within the human genome. Mouse Gukh2 and zebrafish gukh2 genes were also identified. N-terminal part of human GUKH2, mouse Gukh2 and zebrafish gukh2 proteins were completely divergent from human GUKH1 protein. Human GUKH2 and GUKH1, consisting of eight GUKH homology (GKH1-GKH8) domains and Proline-rich domain, showed 28.5% total-amino-acid identity. GKH1, GKH4, GKH5, GKH7 and GKH8 domains were conserved among human GUKH1, human GUKH2 and Drosophila Gukh. Because human homologs of Drosophila dlg (DLG1-DLG7) as well as human homologs of Drosophila scrib (SCRIB, ERBB2IP and Densin-180) are cancer-associated genes, human homologs of Drosophila gukh (GUKH1 and GUKH2) are predicted cancer-associated genes.

LOS GENES BRCA1 y BRCA2. ESTUDIO MOLECULAR

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N. Alonso

2006-11-01

Full Text Available RESUMENEn los últimos años, se realizaron numerosos estudios para establecer la predisposición hereditaria al cáncer y las alteraciones mutacionales a nivel de genes susceptibles de originar cáncer de mama y ovario. En 1994 se identificaron los genes BRCA1 (Breast Cancer Gene 1 y BRCA2 (Breast Cancer Gene 2 como susceptibles de cáncer de mama y ovario. En la actualidad se sabe que las mutaciones en BRCA1 y BRCA2 están lejos de explicar la totalidad de los casos de cáncer de mama y/o ovario, y a pesar de que se postulan alteraciones mutacionales en otros genes como CHEK2, TP53 y PTEN, el BRCA1 y BRCA2, siguen teniendo su importancia y utilidad en la valoración del riesgo de predisposición hereditaria. Aunque las cifras son variables según los distintos estudios y autores, se trata en cualquier caso de porcentajes importantes. Entre el 15 y el 85% de las mujeres portadoras de mutación BRCA 1 o BRCA 2 tienen riesgo de desarrollar un cáncer de mama y entre un 10 y 60% de desarrollar un cáncer de ovario. ABSTRACT:In the last years, numerous studies were made to establish the hereditary predisposition to the cancer and the mutationals alterations at level of genes susceptible to originate breast and ovarian cancers. In 1994 genes BRCA1 (Breast Cancer Gene 1 and BRCA2 were identified (Breast Cancer Gene 2 as susceptible of both of breast and ovarian cancers. At the present time, it is knows that the mutations in BRCA 1 and BRCA 2 are far from explaining the totality of the cases of breast cancer and/or ovary, and although mutationals alterations in other genes like CHEK2, TP53 and PTEN, the BRCA1 and BRCA2 are postulated, they continue having his importance and utility in the valuation of the risk of hereditary predisposition. Correlations between both BRCA1 and BRCA2 levels with tumour grade metastasis and prognostic accuracy. Between 15 and 85% of the carrying women of mutation BRCA 1 or BRCA 2 have risk of developing a cancer of breast

The SH2D2A gene and susceptibility to multiple sclerosis

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Lorentzen, A.R.; Smestad, C.; Lie, B.A.

2008-01-01

We previously reported an association between the SH2D2A gene encoding TSAd and multiple sclerosis (MS). Here a total of 2128 Nordic MS patients and 2004 controls were genotyped for the SH2D2A promoter GA repeat polymorphism and rs926103 encoding a serine to asparagine substitution at amino acid...... that the SH2D2A gene may contribute to susceptibility to MS Udgivelsesdato: 2008/7/15...

Polymorphisms rs12998 and rs5780218 in KiSS1 Suppressor Metastasis Gene in Mexican Patients with Breast Cancer

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Edhit Guadalupe Cruz Quevedo

2015-01-01

Full Text Available Aims. KiSS1 is a metastasis suppressor gene associated with inhibition of cellular chemotaxis and invasion attenuating the metastasis in melanoma and breast cancer cell lines. Along the KiSS-1 gene at least 294 SNPs have been described; however the association of these polymorphisms as genetic markers for metastasis in breast cancer studies has not been investigated. Here we describe two simple PCR-RFLPs protocols to identify the rs5780218 (9DelT and the rs12998 (E20K KiSS1 polymorphisms and the allelic, genotypic, and haplotypic frequencies in Mexican general population (GP and patients with benign breast disease (BBD or breast cancer (BC. Results. The rs5780218 polymorphism was individually associated with breast cancer (P=0.0332 and the rs12998 polymorphism shows statistically significant differences when GP versus case (BC and BBD groups were compared (P<0.0001. The H1 Haplotype (G/- occurred more frequently in BC group (0.4256 whereas H2 haplotype (G/T was the most prevalent in BBD group (0.4674. Conclusions. Our data indicated that the rs5780218 polymorphism individually confers susceptibility for development of breast cancer in Mexican population and a possible role as a genetic marker in breast cancer metastasis for H1 haplotype (Wt/variant in KiSS1 gene must be analyzed in other populations.

Evolutionary genomics of plant genes encoding N-terminal-TM-C2 domain proteins and the similar FAM62 genes and synaptotagmin genes of metazoans

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Craxton Molly

2007-07-01

Full Text Available Abstract Background Synaptotagmin genes are found in animal genomes and are known to function in the nervous system. Genes with a similar domain architecture as well as sequence similarity to synaptotagmin C2 domains have also been found in plant genomes. The plant genes share an additional region of sequence similarity with a group of animal genes named FAM62. FAM62 genes also have a similar domain architecture. Little is known about the functions of the plant genes and animal FAM62 genes. Indeed, many members of the large and diverse Syt gene family await functional characterization. Understanding the evolutionary relationships among these genes will help to realize the full implications of functional studies and lead to improved genome annotation. Results I collected and compared plant Syt-like sequences from the primary nucleotide sequence databases at NCBI. The collection comprises six groups of plant genes conserved in embryophytes: NTMC2Type1 to NTMC2Type6. I collected and compared metazoan FAM62 sequences and identified some similar sequences from other eukaryotic lineages. I found evidence of RNA editing and alternative splicing. I compared the intron patterns of Syt genes. I also compared Rabphilin and Doc2 genes. Conclusion Genes encoding proteins with N-terminal-transmembrane-C2 domain architectures resembling synaptotagmins, are widespread in eukaryotes. A collection of these genes is presented here. The collection provides a resource for studies of intron evolution. I have classified the collection into homologous gene families according to distinctive patterns of sequence conservation and intron position. The evolutionary histories of these gene families are traceable through the appearance of family members in different eukaryotic lineages. Assuming an intron-rich eukaryotic ancestor, the conserved intron patterns distinctive of individual gene families, indicate independent origins of Syt, FAM62 and NTMC2 genes. Resemblances

Introducing the "TCDD-inducible AhR-Nrf2 gene battery".

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Yeager, Ronnie L; Reisman, Scott A; Aleksunes, Lauren M; Klaassen, Curtis D

2009-10-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces genes via the transcription factor aryl hydrocarbon receptor (AhR), including Cyp1a1, NAD(P)H:quinone oxidoreductase 1 (Nqo1), UDP-glucuronosyltransferase 1a6 (Ugt1a6), and glutathione S-transferase a1 (Gsta1). These genes are referred to as the "AhR gene battery." However, Nqo1 is also considered a prototypical target gene of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). In mice, TCDD induction of Nrf2 and Nrf2 target, Nqo1, is dependent on AhR, and thus TCDD induction of drug-processing genes may be routed through an AhR-Nrf2 sequence. There has been speculation that Nrf2 may be involved in the TCDD induction of drug-processing genes; however, the data are not definitive. Therefore, to address whether TCDD induction of Nqo1, Ugts, and Gsts is dependent on Nrf2, we conducted the definitive experiment by administering TCDD (50 mug/kg, ip) to Nrf2-null and wild-type (WT) mice and collecting livers 24 h later to quantify the mRNA of drug-processing genes. TCDD induction of Cyp1a1 and Ugt1a1 was similar in WT and Nrf2-null mice, whereas TCDD induction of Ugt1a5 and 1a9 was blunted in Nrf2-null mice. TCDD induced Nqo1, Ugt1a6, 2b34, 2b35, 2b36, UDP-glucuronic acid-synthesizing gene UDP-glucose dehydrogenase, and Gsta1, m1, m2, m3, m6, p2, t2, and microsomal Gst1 in WT mice but not in Nrf2-null mice. Therefore, the present study demonstrates the novel finding that Nrf2 is required for TCDD induction of classical AhR battery genes Nqo1, Ugt1a6, and Gsta1, as well as most Ugt and Gst isoforms in livers of mice.

Gene duplications in prokaryotes can be associated with environmental adaptation

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Lempicki Richard A

2010-10-01

Full Text Available Abstract Background Gene duplication is a normal evolutionary process. If there is no selective advantage in keeping the duplicated gene, it is usually reduced to a pseudogene and disappears from the genome. However, some paralogs are retained. These gene products are likely to be beneficial to the organism, e.g. in adaptation to new environmental conditions. The aim of our analysis is to investigate the properties of paralog-forming genes in prokaryotes, and to analyse the role of these retained paralogs by relating gene properties to life style of the corresponding prokaryotes. Results Paralogs were identified in a number of prokaryotes, and these paralogs were compared to singletons of persistent orthologs based on functional classification. This showed that the paralogs were associated with for example energy production, cell motility, ion transport, and defence mechanisms. A statistical overrepresentation analysis of gene and protein annotations was based on paralogs of the 200 prokaryotes with the highest fraction of paralog-forming genes. Biclustering of overrepresented gene ontology terms versus species was used to identify clusters of properties associated with clusters of species. The clusters were classified using similarity scores on properties and species to identify interesting clusters, and a subset of clusters were analysed by comparison to literature data. This analysis showed that paralogs often are associated with properties that are important for survival and proliferation of the specific organisms. This includes processes like ion transport, locomotion, chemotaxis and photosynthesis. However, the analysis also showed that the gene ontology terms sometimes were too general, imprecise or even misleading for automatic analysis. Conclusions Properties described by gene ontology terms identified in the overrepresentation analysis are often consistent with individual prokaryote lifestyles and are likely to give a competitive

BMP2 and BMP7 play antagonistic roles in feather induction

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Michon, Frédéric; Forest, Loïc; Collomb, Elodie; Demongeot, Jacques; Dhouailly, Danielle

2008-01-01

Summary During embryonic development, feathers first appear as primordia consisting of an epidermal placode associated with a dermal condensation. In most previous studies, the BMPs have been proposed to function as inhibitors of the formation of cutaneous appendages. We showed that the function of BMPs is quite nuanced: BMP-2 and BMP-7, which are expressed in both skin components, act antagonistically and yet are both involved in the dermal condensations formation. BMP-7, the first to be expressed, is implicated in chemotaxis which leads to cell recruitment to the condensation, whereas BMP-2, which is expressed later, leads to an arrest of cell migration, likely via its modulation of EIIIA Fibronectin domain and α4-Integrin expression. We also propose a mathematical model, a reaction-diffusion system, based on cell proliferation, chemotaxis and the timing of BMP-2 and BMP-7 expression, which simulates the endogenous situation and reproduces the negative effects of excess BMP-2 or BMP-7 on feather patterning. PMID:18635609

The level of CD147 expression correlates with cyclophilin-induced signalling and chemotaxis

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Constant Stephanie

2011-10-01

Full Text Available Abstract Background Previous studies identified CD147 as the chemotactic receptor on inflammatory leukocytes for extracellular cyclophilins (eCyp. However, CD147 is not known to associate with signal transducing molecules, so other transmembrane proteins, such as proteoglycans, integrins, and CD98, were suggested as receptor or co-receptor for eCyp. CD147 is ubiquitously expressed on many cell types, but relationship between the level of CD147 expression and cellular responses to eCyp has never been analyzed. Given the role of eCyp in pathogenesis of many diseases, it is important to know whether cellular responses to eCyp are regulated at the level of CD147 expression. Results Here, we manipulated CD147 expression levels on HeLa cells using RNAi and investigated the signalling and chemotactic responses to eCypA. Both Erk activation and chemotaxis correlated with the level of CD147 expression, with cells exhibiting low level expression being practically unresponsive to eCypA. Conclusions Our results provide the first demonstration of a chemotactic response of HeLa cells to eCypA, establish a correlation between the level of CD147 expression and the magnitude of cellular responses to eCypA, and indicate that CD147 may be a limiting factor in the receptor complex determining cyclophilin-induced Erk activation and cell migration.

Expression of KLK2 gene in prostate cancer

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Sajad Shafai

2018-01-01

Conclusion: The expression of KLK2 gene in people with prostate cancer is the higher than the healthy person; finally, according to the results, it could be mentioned that the KLK2 gene considered as a useful factor in prostate cancer, whose expression is associated with progression and development of the prostate cancer.

Characterization of the human laminin beta2 chain locus (LAMB2): linkage to a gene containing a nonprocessed, transcribed LAMB2-like pseudogene (LAMB2L) and to the gene encoding glutaminyl tRNA synthetase (QARS)

DEFF Research Database (Denmark)

Durkin, M E; Jäger, A C; Khurana, T S

1999-01-01

The laminin beta2 chain is an important constituent of certain kidney and muscle basement membranes. We have generated a detailed physical map of a 110-kb genomic DNA segment surrounding the human laminin beta2 chain gene (LAMB2) on chromosome 3p21.3-->p21.2, a region paralogous with the chromosome...... 7q22-->q31 region that contains the laminin beta1 chain gene locus (LAMB1). Several CpG islands and a novel polymorphic microsatellite marker (D3S4594) were identified. The 3' end of LAMB2 lies 16 kb from the 5' end of the glutaminyl tRNA synthetase gene (QARS). About 20 kb upstream of LAMB2 we...... found a gene encoding a transcribed, non-processed LAMB2-like pseudogene (LAMB2L). The sequence of 1.75 kb of genomic DNA at the 3' end of LAMB2L was similar to exons 8-12 of the laminin beta2 chain gene. The LAMB2L-LAMB2-QARS cluster lies telomeric to the gene encoding the laminin-binding protein...

Genomic organization of the rat alpha 2u-globulin gene cluster.

Science.gov (United States)

McFadyen, D A; Addison, W; Locke, J

1999-05-01

The alpha 2u-globulin are a group of similar proteins, belonging to the lipocalin superfamily of proteins, that are synthesized in a subset of secretory tissues in rats. The many alpha 2u-globulin isoforms are encoded by a multigene family that exhibits extensive homology. Despite a high degree of sequence identity, individual family members show diverse expression patterns involving complex hormonal, tissue-specific, and developmental regulation. Analysis suggests that there are approximately 20 alpha 2u-globulin genes in the rat genome. We have used fluorescence in situ hybridization (FISH) to show that the alpha 2u-globulin genes are clustered at a single site on rat Chromosome (Chr) 5 (5q22-24). Southern blots of rat genomic DNA separated by pulsed field gel electrophoresis indicated that the alpha 2u-globulin genes are contained on two NruI fragments with a total size of 880 kbp. Analysis of three P1 clones containing alpha 2u-globulin genes indicated that the alpha 2u-globulin genes are tandemly arranged in a head-to-tail fashion. The organization of the alpha 2u-globulin genes in the rat as a tandem array of single genes differs from the homologous major urinary protein genes in the mouse, which are organized as tandem arrays of divergently oriented gene pairs. The structure of these gene clusters may have consequences for the proposed function, as a pheromone transporter, for the protein products encoded by these genes.

Informative gene selection using Adaptive Analytic Hierarchy Process (A2HP

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Abhishek Bhola

2017-12-01

Full Text Available Gene expression dataset derived from microarray experiments are marked by large number of genes, which contains the gene expression values at different sample conditions/time-points. Selection of informative genes from these large datasets is an issue of major concern for various researchers and biologists. In this study, we propose a gene selection and dimensionality reduction method called Adaptive Analytic Hierarchy Process (A2HP. Traditional analytic hierarchy process is a multiple-criteria based decision analysis method whose result depends upon the expert knowledge or decision makers. It is mainly used to solve the decision problems in different fields. On the other hand, A2HP is a fused method that combines the outcomes of five individual gene selection ranking methods t-test, chi-square variance test, z-test, wilcoxon test and signal-to-noise ratio (SNR. At first, the preprocessing of gene expression dataset is done and then the reduced number of genes obtained, will be fed as input for A2HP. A2HP utilizes both quantitative and qualitative factors to select the informative genes. Results demonstrate that A2HP selects efficient number of genes as compared to the individual gene selection methods. The percentage of deduction in number of genes and time complexity are taken as the performance measure for the proposed method. And it is shown that A2HP outperforms individual gene selection methods.

Coamplification in tumors of KRAS2, type 2 inositol 1,4,5 triphosphate receptor gene, and a novel human gene, KRAG

Energy Technology Data Exchange (ETDEWEB)

Heighway, J.; Betticher, D.C.; Altermatt, H.J. [Univ. Hospital of Berne (Switzerland)] [and others

1996-07-01

Analysis of a region of DNA, coamplified in tumors with KRAS2, resulted in the identification of the human homologue of the mouse KRAG gene. The gene was widely expressed in range of cell lines, tumors, and normal tissue and demonstrated a high degree of alternate splicing. A human KRAG cDNA sequence, with a structure similar to that encoded by the amplified gene in mouse Y1 adrenal carcinoma cells, was isolated by RT-PCR. The predicted amino acid similarity between the two sequences was 91%, and hydrophobicity plots suggested a structure closely resembling that of transmembrane 4 superfamily members. Identification of a PCR-based restriction fragment length polymorphism allele-specific splicing differences in tumors. Northern analysis of mRNA derived from a range of tissues suggested high level expression in muscle and confirmed alternate splicing. To facilitate the analysis of exon junctions, a YAC clone encoding the genomic sequence was identified. This allowed the localization of KRAG to human chromosome 12p11.2. Isolation of one end of this nonchimeric clone demonstrated a perfect match with a 247-bp sequence within the 3{prime} untranslated region of the type 2 1,4,5-inositol triphosphate receptor gene. Multiplex PCR confirmed the inclusion of both genes. Multiplex PCR confirmed the inclusion of both genes in the KRAS2 amplicon in human malignancy, suggesting that either may contribute to the malignant phenotypes. 35 refs., 6 figs., 1 tab.

The human MCP-2 gene (SCYA8): Cloning, sequence analysis, tissue expression, and assignment to the CC chemokine gene contig on chromosome 17q11.2

Energy Technology Data Exchange (ETDEWEB)

Van Coillie, E.; Fiten, P.; Van Damme, J.; Opdenakker, G. [Univ. of Leuven (Belgium)] [and others

1997-03-01

Monocyte chemotactic proteins (MCPs) form a subfamily of chemokines that recruit leukocytes to sites of inflammation and that may contribute to tumor-associated leukocyte infiltration and to the antiviral state against HIV infection. With the use of degenerate primers that were based on CC chemokine consensus sequences, the known MIP-1{alpha}/LD78{alpha}, MCP-1, and MCP-3 genes and the previously unidentified eotaxin and MCP-2 genes were isolated from a YAC contig from human chromosome 17q11.2. The amplified genomic MCP-2 fragment was used to isolate an MCP-2 cosmid from which the gene sequence was determined. The MCP-2 gene shares with the MCP-1 and MCP-3 genes a conserved intron-exon structure and a coding nucleotide sequence homology of 77%. By Northern blot analysis the 1.0-kb MCP-2 mRNA was predominantly detectable in the small intestine, peripheral blood, heart, placenta, lung, skeletal muscle, ovary, colon, spinal cord, pancreas, and thymus. Transcripts of 1.5 and 2.4 kb were found in the testis, the small intestine, and the colon. The isolation of the MCP-2 gene from the chemokine contig localized it on YAC clones of chromosome 17q11.2, which also contain the eotaxin, MCP-1, MCP-3, and NCC-1/MCP-4 genes. The combination of using degenerate primer PCR and YACs illustrates that novel genes can efficiently be isolated from gene cluster contigs with less redundancy and effort than the isolation of novel ESTs. 42 refs., 5 figs., 2 tabs.

Differential gene expression profile associated with the abnormality of bone marrow mesenchymal stem cells in aplastic anemia.

Directory of Open Access Journals (Sweden)

Jianping Li

Full Text Available Aplastic anemia (AA is generally considered as an immune-mediated bone marrow failure syndrome with defective hematopoietic stem cells (HSCs and marrow microenvironment. Previous studies have demonstrated the defective HSCs and aberrant T cellular-immunity in AA using a microarray approach. However, little is known about the overall specialty of bone marrow mesenchymal stem cells (BM-MSCs. In the present study, we comprehensively compared the biological features and gene expression profile of BM-MSCs between AA patients and healthy volunteers. In comparison with healthy controls, BM-MSCs from AA patients showed aberrant morphology, decreased proliferation and clonogenic potential and increased apoptosis. BM-MSCs from AA patients were susceptible to be induced to differentiate into adipocytes but more difficult to differentiate into osteoblasts. Consistent with abnormal biological features, a large number of genes implicated in cell cycle, cell division, proliferation, chemotaxis and hematopoietic cell lineage showed markedly decreased expression in BM-MSCs from AA patients. Conversely, more related genes with apoptosis, adipogenesis and immune response showed increased expression in BM-MSCs from AA patients. The gene expression profile of BM-MSCs further confirmed the abnormal biological properties and provided significant evidence for the possible mechanism of the destruction of the bone marrow microenvironment in AA.

Characterization of Campylobacter jejuni and Campylobacter coli Broiler Isolates by Whole-Genome Sequencing

DEFF Research Database (Denmark)

Cantero, Guillermo; Correa-Fiz, Florencia; Ronco, Troels

2017-01-01

-associated genes studied related to motility, chemotaxis, adhesion, and invasion. Interestingly, the wlaN gene involved in the Guillain–Barré syndrome was found in two isolates. The results underline the power of WGS for investigation of virulence, clonality, and antimicrobial resistance in Campylobacter....

Leukotriene D4 induces chemotaxis in human eosinophilc cell line, EoL-1 cells via CysLT1 receptor activation.

Science.gov (United States)

Shirasaki, Hideaki; Kanaizumi, Etsuko; Himi, Tetsuo

2017-11-01

Numerous reports have shown that cysteinyl leukotrienes (CysLTs) contribute to tissue accumulation of eosinophils in allergic airway inflammation. To date, only a few studies have reported that CysLTs promote chemotactic activity of human eosinophils in vitro. The purpose of this study was to investigate whether CysLTs promote chemotaxis in the human eosinophilic cell line, EoL-1. EoL-1 cells were induced to differentiate into mature eosinophil-like cells via incubation with butyric acid and cytokines (IL-3, IL-5 and GM-CSF). The chemotactic activity of the differentiated EoL-1 cells was assessed using the commercial cell migration assay kit. LTD 4 elicited dose-related chemotactic activity in the differntiated EoL-1 cells in the range of 1-100 nM. A typical bell-shaped dose-response curve was observed with optimal activity at 10 nM. The chemotactic activity elicited by LTD 4 (10 nM) was significantly inhibited by montelukast (control, 345 ± 19.2 × 10 3 RFU; LTD 4 10 nM alone, 511 ± 39.2 × 10 3 RFU; LTD 4 10 nM plus montelukast 100 nM, 387 ± 28.2 × 10 3 RFU). LTD 4 induces migration in eosinophilic cells via activation of CysLT1 receptor. The present in vitro model may be useful for elucidation of the mechanism underlying CysLT-induced tissue eosinophilia.

Gene Expression Profiling Identifies Important Genes Affected by R2 Compound Disrupting FAK and P53 Complex

International Nuclear Information System (INIS)

Golubovskaya, Vita M.; Ho, Baotran; Conroy, Jeffrey; Liu, Song; Wang, Dan; Cance, William G.

2014-01-01

Focal Adhesion Kinase (FAK) is a non-receptor kinase that plays an important role in many cellular processes: adhesion, proliferation, invasion, angiogenesis, metastasis and survival. Recently, we have shown that Roslin 2 or R2 (1-benzyl-15,3,5,7-tetraazatricyclo[3.3.1.1~3,7~]decane) compound disrupts FAK and p53 proteins, activates p53 transcriptional activity, and blocks tumor growth. In this report we performed a microarray gene expression analysis of R2-treated HCT116 p53 +/+ and p53 −/− cells and detected 1484 genes that were significantly up- or down-regulated (p < 0.05) in HCT116 p53 +/+ cells but not in p53 −/− cells. Among up-regulated genes in HCT p53 +/+ cells we detected critical p53 targets: Mdm-2, Noxa-1, and RIP1. Among down-regulated genes, Met, PLK2, KIF14, BIRC2 and other genes were identified. In addition, a combination of R2 compound with M13 compound that disrupts FAK and Mmd-2 complex or R2 and Nutlin-1 that disrupts Mdm-2 and p53 decreased clonogenicity of HCT116 p53 +/+ colon cancer cells more significantly than each agent alone in a p53-dependent manner. Thus, the report detects gene expression profile in response to R2 treatment and demonstrates that the combination of drugs targeting FAK, Mdm-2, and p53 can be a novel therapy approach

Association of -330 interleukin-2 gene polymorphism with oral cancer.

Science.gov (United States)

Singh, Prithvi Kumar; Kumar, Vijay; Ahmad, Mohammad Kaleem; Gupta, Rajni; Mahdi, Abbas Ali; Jain, Amita; Bogra, Jaishri; Chandra, Girish

2017-12-01

Cytokines play an important role in the development of cancer. Several single-nucleotide polymorphisms (SNPs) of cytokine genes have been reported to be associated with the development and severity of inflammatory diseases and cancer predisposition. This study was undertaken to evaluate a possible association of interleukin 2 (IL-2) (- 330A>C) gene polymorphisms with the susceptibility to oral cancer. The SNP in IL-2 (-330A>C) gene was genotyped in 300 oral cancer patients and in similar number of healthy volunteers by polymerase chain reaction (PCR)-restriction fragment length polymorphism and the association of the gene with the disease was evaluated. IL-2 (-330A>C) gene polymorphism was significantly associated with oral cancer whereas it was neither associated with clinicopathological status nor with cancer pain. The AC heterozygous genotype was significantly associated with oral cancer patients as compared to controls [odds ratio (OR): 3.0; confidence interval (CI): 2.14-4.20; Poral cancer (OR: 1.80; CI: 1.39-2.33; PC) gene polymorphism was also associated with oral cancer in tobacco smokers and chewers. Our results showed that oral cancer patients had significantly higher frequency of AA genotype but significantly lower frequency of AC genotype and C allele compared to controls. The IL-2 AC genotype and C allele of IL-2 (-330A>C) gene polymorphisms could be potential protective factors and might reduce the risk of oral cancer in Indian population.

Geodynamic processes in the NW Bohemian swarm earthquake region, Czech Republic, identified by continuous gas monitoring

Czech Academy of Sciences Publication Activity Database

Weinlich, F.H.; Stejskal, Vladimír; Teschner, M.; Poggenburg, J.

2013-01-01

Roč. 13, č. 3 (2013), s. 305-330 ISSN 1468-8115 Institutional research plan: CEZ:AV0Z30460519 Keywords : carbon dioxide * Cheb Basin * co-seismic anomalies Subject RIV: DD - Geochemistry Impact factor: 1.431, year: 2013

Identification of Aquifex aeolicus tRNA (m2(2G26) methyltransferase gene.

Science.gov (United States)

Takeda, Hiroshi; Hori, Hiroyuki; Endo, Yaeta

2002-01-01

The modifications of N2,N2-dimethylguanine (m2(2)G) are found in tRNAs and rRNAs from eukarya and archaea. In tRNAs, modification at position G26 is generated by tRNA (m2(2)G26) methyltransferase, which is encoded by the corresponding gene, trm1. This enzyme catalyzes the methyl-transfer from S-adenosyl-L-methionine to the semi-conserved residue, G26, via the intermediate modified base, m2G26. Recent genome sequencing project has been reported that the putative trm1 is encoded in the genome of Aquifex aeolicus, a hyper-thermophilic eubacterium as only one exception among eubacteria. In order to confirm whether this bacterial trm1 gene product is a real tRNA (m2(2)G26) methyltransferase or not, we expressed this protein by wheat germ in vitro cell-free translation system. Our biochemical analysis clearly showed that this gene product possessed tRNA (m2(2)G26) methyltransferase activity.

Regulation of the cytochrome P450 2A genes

International Nuclear Information System (INIS)

Su Ting; Ding Xinxin

2004-01-01

Cytochrome P450 monooxygenases of the CYP2A subfamily play important roles in xenobiotic disposition in the liver and in metabolic activation in extrahepatic tissues. Many of the CYP2A transcripts and enzymes are inducible by xenobiotic compounds, and the expression of at least some of the CYP2A genes is influenced by physiological status, such as circadian rhythm, and pathological conditions, such as inflammation, microbial infection, and tumorigenesis. Variability in the expression of the CYP2A genes, which differs by species, animal strain, gender, and organ, may alter the risks of chemical toxicity for numerous compounds that are CYP2A substrates. The mechanistic bases of these variabilities are generally not well understood. However, recent studies have yielded interesting findings in several areas, such as the role of nuclear factor 1 in the tissue-selective expression of CYP2A genes in the olfactory mucosa (OM); the roles of constitutive androstane receptor, pregnane X receptor (PXR), and possibly, peroxisome proliferator-activated receptors in transcriptional regulation of the Cyp2a5 gene; and the involvement of heterogeneous nuclear ribonucleoprotein A1 in pyrazole-induced stabilization of CYP2A5 mRNA. The aims of this minireview are to summarize current knowledge of the regulation of the CYP2A genes in rodents and humans, and to stimulate further mechanistic studies that will ultimately improve our ability to determine, and to understand, these variabilities in humans

Genes associated with Type 2 Diabetes and vascular complications.

Science.gov (United States)

Montesanto, Alberto; Bonfigli, Anna Rita; Crocco, Paolina; Garagnani, Paolo; De Luca, Maria; Boemi, Massimo; Marasco, Elena; Pirazzini, Chiara; Giuliani, Cristina; Franceschi, Claudio; Passarino, Giuseppe; Testa, Roberto; Olivieri, Fabiola; Rose, Giuseppina

2018-02-04

Type 2 Diabetes (T2D) is a chronic disease associated with a number of micro- and macrovascular complications that increase the morbidity and mortality of patients. The risk of diabetic complications has a strong genetic component. To this end, we sought to evaluate the association of 40 single nucleotide polymorphisms (SNPs) in 21 candidate genes with T2D and its vascular complications in 503 T2D patients and 580 healthy controls. The genes were chosen because previously reported to be associated with T2D complications and/or with the aging process. We replicated the association of T2D risk with I GF2BP rs4402960 and detected novel associations with TERT rs2735940 and rs2736098. The addition of these SNPs to a model including traditional risk factors slightly improved risk prediction. After stratification of patients according to the presence/absence of vascular complications, we found significant associations of variants in the CAT , FTO , and UCP1 genes with diabetic retinopathy and nephropathy. Additionally, a variant in the ADIPOQ gene was found associated with macrovascular complications. Notably, these genes are involved in some way in mitochondrial biology and reactive oxygen species regulation. Hence, our findings strongly suggest a potential link between mitochondrial oxidative homeostasis and individual predisposition to diabetic vascular complications.

Sea urchin neural alpha2 tubulin gene: isolation and promoter analysis.

Science.gov (United States)

Costa, S; Ragusa, M A; Drago, G; Casano, C; Alaimo, G; Guida, N; Gianguzza, F

2004-04-02

Expression of Talpha2 gene, during sea urchin Paracentrotus lividus development, is spatially and temporally regulated. In order to characterize this gene, we isolated the relevant genomic sequences and scanned the isolated 5'-flanking region in searching for cis-regulatory elements required for proper expression. Gel mobility shift and footprinting assays, as well as reporter gene (CAT and beta-gal) expression assays, were used to address cis-regulatory elements involved in regulation. Here we report that an upstream 5'-flanking fragment of PlTalpha2 gene drives temporal expression of reporter genes congruent with that of endogenous Talpha2 gene. The fragment contains cis-elements able to bind nuclear proteins from the gastrula stage (at which the Talpha2 gene is expressed) whose sequences could be consistent with the consensus sequences for transcription factors present in data bank.

Sequence analysis of the N-acetyltransferase 2 gene (NAT2) among ...

African Journals Online (AJOL)

Yazun Bashir Jarrar

2017-11-26

Nov 26, 2017 ... Sequence analysis of the N-acetyltransferase 2 gene (NAT2) among Jordanian volunteers, Libyan. Journal of Medicine .... For molecular modeling of NAT2 protein, visualized ..... cal clustering. .... cular dynamics simulation.

The Dopamine D2 Receptor Gene, Perceived Parental Support, and Adolescent Loneliness: Longitudinal Evidence for Gene-Environment Interactions

Science.gov (United States)

van Roekel, Eeske; Goossens, Luc; Scholte, Ron H. J.; Engels, Rutger C. M. E.; Verhagen, Maaike

2011-01-01

Background: Loneliness is a common problem in adolescence. Earlier research focused on genes within the serotonin and oxytocin systems, but no studies have examined the role of dopamine-related genes in loneliness. In the present study, we focused on the dopamine D2 receptor gene (DRD2). Methods: Associations among the DRD2, sex, parental support,…

Glucokinase gene mutations (MODY 2) in Asian Indians.

Science.gov (United States)

Kanthimathi, Sekar; Jahnavi, Suresh; Balamurugan, Kandasamy; Ranjani, Harish; Sonya, Jagadesan; Goswami, Soumik; Chowdhury, Subhankar; Mohan, Viswanathan; Radha, Venkatesan

2014-03-01

Heterozygous inactivating mutations in the glucokinase (GCK) gene cause a hyperglycemic condition termed maturity-onset diabetes of the young (MODY) 2 or GCK-MODY. This is characterized by mild, stable, usually asymptomatic, fasting hyperglycemia that rarely requires pharmacological intervention. The aim of the present study was to screen for GCK gene mutations in Asian Indian subjects with mild hyperglycemia. Of the 1,517 children and adolescents of the population-based ORANGE study in Chennai, India, 49 were found to have hyperglycemia. These children along with the six patients referred to our center with mild hyperglycemia were screened for MODY 2 mutations. The GCK gene was bidirectionally sequenced using BigDye(®) Terminator v3.1 (Applied Biosystems, Foster City, CA) chemistry. In silico predictions of the pathogenicity were carried out using the online tools SIFT, Polyphen-2, and I-Mutant 2.0 software programs. Direct sequencing of the GCK gene in the patients referred to our Centre revealed one novel mutation, Thr206Ala (c.616A>G), in exon 6 and one previously described mutation, Met251Thr (c.752T>C), in exon 7. In silico analysis predicted the novel mutation to be pathogenic. The highly conserved nature and critical location of the residue Thr206 along with the clinical course suggests that the Thr206Ala is a MODY 2 mutation. However, we did not find any MODY 2 mutations in the 49 children selected from the population-based study. Hence prevalence of GCK mutations in Chennai is MODY 2 mutations from India and confirms the importance of considering GCK gene mutation screening in patients with mild early-onset hyperglycemia who are negative for β-cell antibodies.

The genetic alteration of MTS1/CDKN2 gene in esophageal cancer

International Nuclear Information System (INIS)

Zo, Jae Ill; Paik, Hee Jong; Park, Jong Ho; Kim, Mi Hee

1996-12-01

MTS1/CDKN2 gene plays a key role in cell cycle regulation, and there have been many studies about the significance of this gene in tumorigenesis. To investigate the frequency of MTS1/CDKN2 gene alteration in Korean esophageal cancer, we studied 36 esophageal cancer tissues with paired PCR analysis to detect homozygous deletion and PCR-SSCP methods to find minute mutations, if any. In the cases with abnormalities, the nucleotide sequence analysis was performed. And in cases without RB gene a alterations, direct sequence analysis was also done. There was no homozygous deletions. Mobility shift by PCR-SSCP was observed in four cases at exon 2, which showed 1 bp deletion in codon 97 of mutation in codon 100 which changed TAT (Tyr) from GAT (Asp). But there were not MTS1/CDKN2 gene alterations in cases without Rb gene alterations. Analysis of clinical data did not show any differences depending upon MTS1/CDKN2 gene alterations. Therefore the MTS1/CDKN2 gene mutations were infrequent events and do not play a major role in the group of patients examined. More study for contribution of methylation in MTS1/CDKN2 gene for inactivation of p16 should be done before evaluation and application of MTS1/CDKN2 gene in tumorigenesis and as an candidate of gene therapy. (author). 15 refs

The genetic alteration of MTS1/CDKN2 gene in esophageal cancer

Energy Technology Data Exchange (ETDEWEB)

Zo, Jae Ill; Paik, Hee Jong; Park, Jong Ho; Kim, Mi Hee [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1996-12-01

MTS1/CDKN2 gene plays a key role in cell cycle regulation, and there have been many studies about the significance of this gene in tumorigenesis. To investigate the frequency of MTS1/CDKN2 gene alteration in Korean esophageal cancer, we studied 36 esophageal cancer tissues with paired PCR analysis to detect homozygous deletion and PCR-SSCP methods to find minute mutations, if any. In the cases with abnormalities, the nucleotide sequence analysis was performed. And in cases without RB gene a alterations, direct sequence analysis was also done. There was no homozygous deletions. Mobility shift by PCR-SSCP was observed in four cases at exon 2, which showed 1 bp deletion in codon 97 of mutation in codon 100 which changed TAT (Tyr) from GAT (Asp). But there were not MTS1/CDKN2 gene alterations in cases without Rb gene alterations. Analysis of clinical data did not show any differences depending upon MTS1/CDKN2 gene alterations. Therefore the MTS1/CDKN2 gene mutations were infrequent events and do not play a major role in the group of patients examined. More study for contribution of methylation in MTS1/CDKN2 gene for inactivation of p16 should be done before evaluation and application of MTS1/CDKN2 gene in tumorigenesis and as an candidate of gene therapy. (author). 15 refs.

Determining true HER2 gene status in breast cancers with polysomy by using alternative chromosome 17 reference genes: implications for anti-HER2 targeted therapy.

Science.gov (United States)

Tse, Chun Hing; Hwang, Harry C; Goldstein, Lynn C; Kandalaft, Patricia L; Wiley, Jesse C; Kussick, Steven J; Gown, Allen M

2011-11-01

The ratio of human epidermal growth factor receptor 2 (HER2) to CEP17 by fluorescent in situ hybridization (FISH) with the centromeric probe CEP17 is used to determine HER2 gene status in breast cancer. Increases in CEP17 copy number have been interpreted as representing polysomy 17. However, pangenomic studies have demonstrated that polysomy 17 is rare. This study tests the hypothesis that the use of alternative chromosome 17 reference genes might more accurately assess true HER2 gene status. In all, 171 patients with breast cancer who had HER2 FISH that had increased mean CEP17 copy numbers (> 2.6) were selected for additional chromosome 17 studies that used probes for Smith-Magenis syndrome (SMS), retinoic acid receptor alpha (RARA), and tumor protein p53 (TP53) genes. A eusomic copy number exhibited in one or more of these loci was used to calculate a revised HER2-to-chromosome-17 ratio by using the eusomic gene locus as the reference. Of 132 cases classified as nonamplified on the basis of their HER2:CEP17 ratios, 58 (43.9%) were scored as amplified by using alternative chromosome 17 reference gene probes, and 13 (92.9%) of 14 cases scored as equivocal were reclassified as amplified. Among the cases with mean HER2 copy number of 4 to 6, 41 (47.7%) of 86 had their HER2 gene status upgraded from nonamplified to amplified, and four (4.7%) of 86 were upgraded from equivocal to amplified. Our results support the findings of recent pangenomic studies that true polysomy 17 is uncommon. Additional FISH studies that use probes to the SMS, RARA, and TP53 genes are an effective way to determine the true HER2 amplification status in patients with polysomy 17 and they have important potential implications for guiding HER2-targeted therapy in breast cancer.

Mitochondrial nad2 gene is co-transcripted with CMS-associated orfB gene in cytoplasmic male-sterile stem mustard (Brassica juncea).

Science.gov (United States)

Yang, Jing-Hua; Zhang, Ming-Fang; Yu, Jing-Quan

2009-02-01

The transcriptional patterns of mitochondrial respiratory related genes were investigated in cytoplasmic male-sterile and fertile maintainer lines of stem mustard, Brassica juncea. There were numerous differences in nad2 (subunit 2 of NADH dehydrogenase) between stem mustard CMS and its maintainer line. One novel open reading frame, hereafter named orfB gene, was located at the downstream of mitochondrial nad2 gene in the CMS. The novel orfB gene had high similarity with YMF19 family protein, orfB in Raphanus sativus, Helianthus annuus, Nicotiana tabacum and Beta vulgaris, orfB-CMS in Daucus carota, atp8 gene in Arabidopsis thaliana, 5' flanking of orf224 in B. napus (nap CMS) and 5' flanking of orf220 gene in CMS Brassica juncea. Three copies probed by specific fragment (amplified by primers of nad2F and nad2R from CMS) were found in the CMS line following Southern blotting digested with HindIII, but only a single copy in its maintainer line. Meanwhile, two transcripts were shown in the CMS line following Northern blotting while only one transcript was detected in the maintainer line, which were probed by specific fragment (amplified by primers of nad2F and nad2R from CMS). Meanwhile, the expression of nad2 gene was reduced in CMS bud compared to that in its maintainer line. We thus suggested that nad2 gene may be co-transcripted with CMS-associated orfB gene in the CMS. In addition, the specific fragment that was amplified by primers of nad2F and nad2R just spanned partial sequences of nad2 gene and orfB gene. Such alterations in the nad2 gene would impact the activity of NADH dehydrogenase, and subsequently signaling, inducing the expression of nuclear genes involved in male sterility in this type of cytoplasmic male sterility.

Mutagenesis of FAD2 genes in peanut with CRISPR/Cas9

Science.gov (United States)

The CRISPR/Cas9 system is known for its precise and efficient gene-editing of a targeted region in a variety of organisms including plants. We targeted FAD2 gene region to perform CRISPR/Cas9 gene-editing in peanut. The FAD2 gene encodes fatty acid desaturase which catalyzes the conversion of oleic ...

Comparative analysis of vertebrate EIF2AK2 (PKR genes and assignment of the equine gene to ECA15q24–q25 and the bovine gene to BTA11q12–q15

Directory of Open Access Journals (Sweden)

Zharkikh Andrey A

2006-09-01

Full Text Available Abstract The structures of the canine, rabbit, bovine and equine EIF2AK2 genes were determined. Each of these genes has a 5' non-coding exon as well as 15 coding exons. All of the canine, bovine and equine EIF2AK2 introns have consensus donor and acceptor splice sites. In the equine EIF2AK2 gene, a unique single nucleotide polymorphism that encoded a Tyr329Cys substitution was detected. Regulatory elements predicted in the promoter region were conserved in ungulates, primates, rodents, Afrotheria (elephant and Insectifora (shrew. Western clawed frog and fugu EIF2AK2 gene sequences were detected in the USCS Genome Browser and compared to those of other vertebrate EIF2AK2 genes. A comparison of EIF2AK2 protein domains in vertebrates indicates that the kinase catalytic domains were evolutionarily more conserved than the nucleic acid-binding motifs. Nucleotide substitution rates were uniform among the vertebrate sequences with the exception of the zebrafish and goldfish EIF2AK2 genes, which showed substitution rates about 20% higher than those of other vertebrates. FISH was used to physically assign the horse and cattle genes to chromosome locations, ECA15q24–q25 and BTA11q12–15, respectively. Comparative mapping data confirmed conservation of synteny between ungulates, humans and rodents.

The dopamine D2 receptor gene, perceived parental support, and adolescent loneliness : longitudinal evidence for gene-environment interactions

NARCIS (Netherlands)

van Roekel, Eeske; Goossens, Luc; Scholte, Ron H. J.; Engels, Rutger C. M. E.; Verhagen, Maaike

2011-01-01

Background: Loneliness is a common problem in adolescence. Earlier research focused on genes within the serotonin and oxytocin systems, but no studies have examined the role of dopamine-related genes in loneliness. In the present study, we focused on the dopamine D2 receptor gene (DRD2). Methods:

Listeria arpJ gene modifies T helper type 2 subset differentiation.

Science.gov (United States)

Kanoh, Makoto; Maruyama, Saho; Shen, Hua; Matsumoto, Akira; Shinomiya, Hiroto; Przybilla, Karin; Gouin, Edith; Cossart, Pascale; Goebel, Werner; Asano, Yoshihiro

2015-07-15

Although the T-cell subset differentiation pathway has been characterized extensively from the view of host gene regulation, the effects of genes of the pathogen on T-cell subset differentiation during infection have yet to be elucidated. Especially, the bacterial genes that are responsible for this shift have not yet been determined. Utilizing a single-gene-mutation Listeria panel, we investigated genes involved in the host-pathogen interaction that are required for the initiation of T-cell subset differentiation in the early phase of pathogen infection. We demonstrate that the induction of T helper types 1 and 2 (Th1 and Th2) subsets are separate phenomena and are mediated by distinct Listeria genes. We identified several candidate Listeria genes that appear to be involved in the host-Listeria interaction. Among them, arpJ is the strongest candidate gene for inhibiting Th2 subset induction. Furthermore, the analysis utilizing arpJ-deficient Listeria monocytogenes (Lm) revealed that the tumor necrosis factor (TNF) superfamily (Tnfsf) 9-TNF receptor superfamily (Tnfrsf) 9 interaction inhibits the Th2 response during Lm infection. arpJ is the candidate gene for inhibiting Th2 T-cell subset induction. The arpJ gene product influences the expression of Tnfsf/Tnfrsf on antigen-presenting cells and inhibits the Th2 T-cell subset differentiation during Listeria infection. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The Anaphase-Promoting Complex (APC) ubiquitin ligase affects chemosensory behavior in C. elegans.

Science.gov (United States)

Wang, Julia; Jennings, Alexandra K; Kowalski, Jennifer R

2016-01-01

The regulation of fundamental aspects of neurobiological function has been linked to the ubiquitin signaling system (USS), which regulates the degradation and activity of proteins and is catalyzed by E1, E2, and E3 enzymes. The Anaphase-Promoting Complex (APC) is a multi-subunit E3 ubiquitin ligase that controls diverse developmental and signaling processes in post-mitotic neurons; however, potential roles for the APC in sensory function have yet to be explored. In this study, we examined the effect of the APC ubiquitin ligase on chemosensation in Caenorhabditis elegans by testing chemotaxis to the volatile odorants, diacetyl, pyrazine, and isoamyl alcohol, to which wild-type worms are attracted. Animals with loss of function mutations in either of two alleles (g48 and ye143) of the gene encoding the APC subunit EMB-27 APC6 showed increased chemotaxis towards diacetyl and pyrazine, odorants sensed by AWA neurons, but exhibited normal chemotaxis to isoamyl alcohol, which is sensed by AWC neurons. The statistically significant increase in chemotaxis in the emb-27 APC6 mutants suggests that the APC inhibits AWA-mediated chemosensation in C. elegans. Increased chemotaxis to pyrazine was also seen with mutants lacking another essential APC subunit, MAT-2 APC1; however, mat-2 APC1 mutants exhibited wild type responses to diacetyl. The difference in responsiveness of these two APC subunit mutants may be due to differential strength of these hypomorphic alleles or may indicate the presence of functional sub-complexes of the APC at work in this process. These findings are the first evidence for APC-mediated regulation of chemosensation and lay the groundwork for further studies aimed at identifying the expression levels, function, and targets of the APC in specific sensory neurons. Because of the similarity between human and C. elegans nervous systems, the role of the APC in sensory neurons may also advance our understanding of human sensory function and disease.

[High gene conversion frequency between genes encoding 2-deoxyglucose-6-phosphate phosphatase in 3 Saccharomyces species].

Science.gov (United States)

Piscopo, Sara-Pier; Drouin, Guy

2014-05-01

Gene conversions are nonreciprocal sequence exchanges between genes. They are relatively common in Saccharomyces cerevisiae, but few studies have investigated the evolutionary fate of gene conversions or their functional impacts. Here, we analyze the evolution and impact of gene conversions between the two genes encoding 2-deoxyglucose-6-phosphate phosphatase in S. cerevisiae, Saccharomyces paradoxus and Saccharomyces mikatae. Our results demonstrate that the last half of these genes are subject to gene conversions among these three species. The greater similarity and the greater percentage of GC nucleotides in the converted regions, as well as the absence of long regions of adjacent common converted sites, suggest that these gene conversions are frequent and occur independently in all three species. The high frequency of these conversions probably result from the fact that they have little impact on the protein sequences encoded by these genes.

[Effects of canine IL-2 and IL-7 genes on enhancing immunogenicity of canine parvovirus VP2 gene vaccine in mice].

Science.gov (United States)

Chen, Huihui; Zhong, Fei; Li, Xiujin; Wang, Lu; Sun, Yan; Neng, Changai; Zhang, Kao; Li, Wenyan; Wen, Jiexia

2012-11-04

To investigate the effects of canine interleukin-2 (cIL-2) and cIL-7 genes on enhancing the immunogenicity of canine parvovirus (CPV) VP2 DNA vaccine. The bicistronic vectors of cIL-2 and cIL-7 genes were constructed using the eukaryotic expression vector containing internal ribosome entry site (IRES). The cIL-2/ cIL-7 dicistronic vector plus previously constructed vectors, including CPV VP2 DNA vaccine vector, cIL-2 vector and cIL-7 vector, were used to co-immunize mice with different combinations, consisting of VP2 alone, VP2 + cIL-2, VP2 + cIL-7 and VP2 + cIL-2/cIL-7. The VP2-specific antibody levels in immunized mice were measured by ELISA at different time post-immunization. The proliferation indices and interferon-gamma expression were measured by lymphocyte proliferation assay and ELISA, respectively. The cIL-2/cIL-7 bicistronic vector was correct and could mediate cIL-2 and cIL-7 gene expression in eukaryotic cells. Immunization results revealed that the antibody titers and the neutralizing antibody levels of the mice co-immunized with VP2 + cIL-7/cIL-2 vectors were significantly higher than that with either VP2 + cIL-2 vectors or VP2 + cIL-7 vectors (P vaccine.

The GABA A-Receptor γ2 (GABRG2 Gene in obsessive-compulsive disorder O gene do receptor GABA A- γ2 (GABRG2 no transtorno obsessivo-compulsivo

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Margaret A. Richter

2009-12-01

Full Text Available OBJECTIVE: The γ-aminobutyric acid type A (GABA A system may be implicated in obsessive-compulsive disorder, based on its major role in modulation of anxiety and its function as the principal inhibitory neurotransmitter system in the cortex. In addition, glutamatergic/GABAergic mechanisms appear to play a role in the pathophysiology of obsessive-compulsive disorder, making the GABA A receptor-γ2 (GABργ2 gene a good candidate for susceptibility in this disorder. METHOD: 118 probands meeting DSM-IV criteria for primary obsessive-compulsive disorder and their available parents were recruited for participation in this study and informed consent was obtained. An NciI restriction site polymorphism in the second intron was genotyped and data was analyzed using the Transmission Disequilibrium Test. RESULTS: In total, 61 of the participating families were informative (i.e., with at least one heterozygous parent. No biases were observed in the transmission of either of the two alleles (χ2 = 0.016, 1 d.f., p = 0.898 to the affected probands in the total sample. CONCLUSION/DISCUSSION: While these results do not provide support for a major role for the GABA A receptor-γ2 in obsessive-compulsive disorder, further investigations of this gene in larger samples are warranted.OBJETIVO: O sistema gabaérgico tipo A (GABA A pode estar implicado no transtorno obsessivo-compulsivo devido ao seu grande papel na modulação da ansiedade e da sua função como o principal neurotransmissor inibidor no córtex. Além disso, mecanismos glutamatérgicos/gabaérgicos parecem desempenhar um papel na fisiopatologia do transtorno obsessivo-compulsivo, tornando o gene do receptor GABA A-γ2 (GABRG2 um bom gene candidato para a suscetibilidade genética a este transtorno. MÉTODO: 118 probandos que preencheram os critérios do DSM-IV para transtorno obsessivo-compulsivo primário e seus pais (quando disponíveis foram recrutados para a participação neste estudo

UCP2 muscle gene transfer modifies mitochondrial membrane potential.

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Marti, A; Larrarte, E; Novo, F J; Garcia, M; Martinez, J A

2001-01-01

The aim of this work was to evaluate the effect of uncoupling protein 2 (UCP2) muscle gene transfer on mitochondrial activity. Five week-old male Wistar rats received an intramuscular injection of plasmid pXU1 containing UCP2 cDNA in the right tibialis anterior muscles. Left tibialis anterior muscles were injected with vehicle as control. Ten days after DNA injection, tibialis anterior muscles were dissected and muscle mitochondria isolated and analyzed. There were two mitochondrial populations in the muscle after UCP2 gene transfer, one of low fluorescence and complexity and the other, showing high fluorescence and complexity. UCP2 gene transfer resulted in a 3.6 fold increase in muscle UCP2 protein levels compared to control muscles assessed by Western blotting. Furthermore, a significant reduction in mitochondria membrane potential assessed by spectrofluorometry and flow cytometry was observed. The mitochondria membrane potential reduction might account for a decrease in fluorescence of the low fluorescence mitochondrial subpopulation. It has been demonstrated that UCP2 muscle gene transfer in vivo is associated with a lower mitochondria membrane potential. Our results suggest the potential involvement of UCP2 in uncoupling respiration. International Journal of Obesity (2001) 25, 68-74

Alteration of the SETBP1 gene and splicing pathway genes SF3B1, U2AF1, and SRSF2 in childhood acute myeloid leukemia.

Science.gov (United States)

Choi, Hyun-Woo; Kim, Hye-Ran; Baek, Hee-Jo; Kook, Hoon; Cho, Duck; Shin, Jong-Hee; Suh, Soon-Pal; Ryang, Dong-Wook; Shin, Myung-Geun

2015-01-01

Recurrent somatic SET-binding protein 1 (SETBP1) and splicing pathway gene mutations have recently been found in atypical chronic myeloid leukemia and other hematologic malignancies. These mutations have been comprehensively analyzed in adult AML, but not in childhood AML. We investigated possible alteration of the SETBP1, splicing factor 3B subunit 1 (SF3B1), U2 small nuclear RNA auxiliary factor 1 (U2AF1), and serine/arginine-rich splicing factor 2 (SRSF2) genes in childhood AML. Cytogenetic and molecular analyses were performed to reveal chromosomal and genetic alterations. Sequence alterations in the SETBP1, SF3B1, U2AF1, and SRSF2 genes were examined by using direct sequencing in a cohort of 53 childhood AML patients. Childhood AML patients did not harbor any recurrent SETBP1 gene mutations, although our study did identify a synonymous mutation in one patient. None of the previously reported aberrations in the mutational hotspot of SF3B1, U2AF1, and SRSF2 were identified in any of the 53 patients. Alterations of the SETBP1 gene or SF3B1, U2AF1, and SRSF2 genes are not common genetic events in childhood AML, implying that the mutations are unlikely to exert a driver effect in myeloid leukemogenesis during childhood.

rpb2 is a reliable reference gene for quantitative gene expression analysis in the dermatophyte Trichophyton rubrum.

Science.gov (United States)

Jacob, Tiago R; Peres, Nalu T A; Persinoti, Gabriela F; Silva, Larissa G; Mazucato, Mendelson; Rossi, Antonio; Martinez-Rossi, Nilce M

2012-05-01

The selection of reference genes used for data normalization to quantify gene expression by real-time PCR amplifications (qRT-PCR) is crucial for the accuracy of this technique. In spite of this, little information regarding such genes for qRT-PCR is available for gene expression analyses in pathogenic fungi. Thus, we investigated the suitability of eight candidate reference genes in isolates of the human dermatophyte Trichophyton rubrum subjected to several environmental challenges, such as drug exposure, interaction with human nail and skin, and heat stress. The stability of these genes was determined by geNorm, NormFinder and Best-Keeper programs. The gene with the most stable expression in the majority of the conditions tested was rpb2 (DNA-dependent RNA polymerase II), which was validated in three T. rubrum strains. Moreover, the combination of rpb2 and chs1 (chitin synthase) genes provided for the most reliable qRT-PCR data normalization in T. rubrum under a broad range of biological conditions. To the best of our knowledge this is the first report on the selection of reference genes for qRT-PCR data normalization in dermatophytes and the results of these studies should permit further analysis of gene expression under several experimental conditions, with improved accuracy and reliability.

Evidence that the mitochondrial leucyl tRNA synthetase (LARS2) gene represents a novel type 2 diabetes susceptibility gene

DEFF Research Database (Denmark)

hart, Leen M; Hansen, Torben; Rietveld, Ingrid

2005-01-01

Previously, we have shown that a mutation in the mitochondrial DNA-encoded tRNA(Leu(UUR)) gene is associated with type 2 diabetes. One of the consequences of this mutation is a reduced aminoacylation of tRNA(Leu(UUR)). In this study, we have examined whether variants in the leucyl tRNA synthetase...... gene (LARS2), involved in aminoacylation of tRNA(Leu(UUR)), associate with type 2 diabetes. Direct sequencing of LARS2 cDNA from 25 type 2 diabetic subjects revealed eight single nucleotide polymorphisms. Two of the variants were examined in 7,836 subjects from four independent populations...... in the Netherlands and Denmark. A -109 g/a variant was not associated with type 2 diabetes. Allele frequencies for the other variant, H324Q, were 3.5% in type 2 diabetic and 2.7% in control subjects, respectively. The common odds ratio across all four studies was 1.40 (95% CI 1.12-1.76), P = 0.004. There were...

Transcriptome analysis of H2O2-treated wheat seedlings reveals a H2O2-responsive fatty acid desaturase gene participating in powdery mildew resistance.

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Aili Li

Full Text Available Hydrogen peroxide (H(2O(2 plays important roles in plant biotic and abiotic stress responses. However, the effect of H(2O(2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H(2O(2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H(2O(2 treatment for 6 hour in one powdery mildew (PM resistant (PmA and two susceptible (Cha and Han lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H(2O(2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, 'transport' activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H(2O(2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H(2O(2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt. Eight of these genes were found to be co-regulated by H(2O(2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H(2O(2 stress and uncovers potential links between H(2O(2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat.

KIR And HLA Haplotype Analysis in a Family Lacking The KIR 2DL1-2DP1 Genes

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Vojvodić Svetlana

2015-06-01

Full Text Available The killer cell immunoglobulin-like receptor (KIR gene cluster exhibits extensive allelic and haplotypic diversity that is observed as presence/absence of genes, resulting in expansion and contraction of KIR haplotypes and by allelic variation of individual KIR genes. We report a case of KIR pseudogene 2DP1 and 2DL1 gene absence in members of one family with the children suffering from acute myelogenous leukemia (AML. Killer cell immunoglo-bulin-like receptor low resolution genotyping was performed by the polymerase chain reaction (PCR-sequencespecific primers (SSP/sequence-specific oligonucleotide (SSO method and haplotype assignment was done by gene content analysis. Both parents and the maternal grandfather, shared the same Cen-B2 KIR haplotype, containing KIR 3DL3, -2DS2, -2DL2 and -3DP1 genes. The second haplotype in the KIR genotype of the mother and grandfather was Tel-A1 with KIR 2DL4 (normal and deleted variant, -3DL1, -22 bp deletion variant of the 2DS4 gene and -3DL2, while the second haplotype in the KIR genotype of the father was Tel-B1 with 2DL4 (normal variant, -3DS1, -2DL5, -2DS5, -2DS1 and 3DL2 genes. Haplotype analysis in all three offsprings revealed that the children inherited the Cen-B2 haplotype with the same gene content but two of the children inherited a deleted variant of the 2DL4 gene, while the third child inherited a normal one. The second haplotype of all three offspring contained KIR 2DL4, -2DL5, -2DS1, -2DS4 (del 22bp variant, -2DS5, -3DL1 and -3DL2 genes, which was the basis of the assumption that there is a hybrid haplotype and that the present 3DL1 gene is a variant of the 3DS1 gene. Due to consanguinity among the ancestors, the results of KIR segregation analysis showed the existence of a very rare KIR genotype in the offspring. The family who is the subject of this case is even more interesting because the father was 10/10 human leukocyte antigen (HLA-matched to his daughter, all members of the family have

Detection of Lsr2 gene of Mycobacterium leprae in nasal mucus

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Luiz Antonio Custodio

2012-06-01

Full Text Available In the present study, nasal mucus from patients with leprosy were analyzed by PCR using specific primers for Lsr2 gene of Mycobacterium leprae. The presence of Lsr2 gene in the nasal mucus was detected in 25.80% of patients with paucibacillari leprosy, and 23.07% of contacts. Despite the absence of clinical features in the contact individuals, it was possible to detect the presence of Lsr2 gene in the nasal mucus of these individuals. Therefore, PCR detection of M. leprae targeting Lsr2 gene using nasal mucus samples could contribute to early diagnosis of leprosy.

Increased number of anaerobic bacteria in the infected root canal in type 2 diabetic rats.

Science.gov (United States)

Iwama, Akihiro; Morimoto, Taisuke; Tsuji, Masahito; Nakamura, Koki; Higuchi, Naoya; Imaizumi, Ichiro; Shibata, Naoki; Yamasaki, Masahiro; Nakamura, Hiroshi

2006-05-01

The purpose of this study was to investigate the relationship between type 2 diabetes mellitus and anaerobic bacteria detected in infected root canals. Normal Wistar rats (control) received a standard laboratory diet with water (group A), and GK rats (type 2 diabetes mellitus rats) a normal laboratory diet with water (group B) or a 30% sucrose solution (group C). Chemotaxis assay was conducted on polymorphonuclear leukocytes from the 3 groups, and the numbers of anaerobic bacteria in infected root canals were determined. In the chemotaxis assay on the polymorphonuclear leukocytes, the chemotactic response of cells in group C was lower than that for groups A and B (P obligate anaerobic bacteria which stained gram negative, were significantly more numerous in group C (P < .01) than in groups A and B. The metabolic condition produced by type 2 diabetes mellitus in rats might lower the general host resistance against bacterial infection.

Overexpression of mouse TTF-2 gene causes cleft palate

Science.gov (United States)

Meng, Tian; Shi, Jia-Yu; Wu, Min; Wang, Yan; Li, Ling; Liu, Yan; Zheng, Qian; Huang, Lei; Shi, Bing

2012-01-01

In humans, mutations of the gene encoding for thyroid transcription factor-2 (TTF-2 or FOXE1) result in Bamforth syndrome. Bamforth syndrome is characterized by agenesis, cleft palate, spiky hair and choanal atresia. TTF-2 null mice (TTF-2−/−) also exhibit cleft palate, suggesting its involvement in the palatogenesis. However, the molecular pathology and genetic regulation by TTF2 remain largely unknown. In the present study, the recombinant expression vector pBROAD3-TTF-2 containing the promoter of the mouse ROSA26 gene was created to form the structural gene of mouse TTF-2 and was microinjected into the male pronuclei of fertilized ova. Sequence analysis confirmed that the TTF-2 transgenic mouse model was established successfully. The transgenic mice displayed a phenotype of cleft palate. In addition, we found that TTF-2 was highly expressed in the medial edge epithelium (MEE) from the embryonic day 12.5 (E12.5) to E14.5 in TTF-2 transgenic mice. These observations suggest that overexpression of TTF-2 during palatogenesis may contribute to formation of cleft palate. PMID:22304410

A gene-protein assay for human epidermal growth factor receptor 2 (HER2: brightfield tricolor visualization of HER2 protein, the HER2 gene, and chromosome 17 centromere (CEN17 in formalin-fixed, paraffin-embedded breast cancer tissue sections

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Nitta Hiroaki

2012-05-01

Full Text Available Abstract Background The eligibility of breast cancer patients for human epidermal growth factor receptor 2 (HER2-directed therapies is determined by the HER2 gene amplification and/or HER2 protein overexpression status of the breast tumor as determined by in situ hybridization (ISH or immunohistochemistry (IHC, respectively. Our objective was to combine the US Food and Drug Administration (FDA-approved HER2 & chromosome 17 centromere (CEN17 brightfield ISH (BISH and HER2 IHC assays into a single automated HER2 gene-protein assay allowing simultaneous detection of all three targets in a single tissue section. Methods The HER2 gene-protein assay was optimized using formalin-fixed, paraffin-embedded (FFPE samples of the xenograft tumors MCF7 [HER2 negative (non-amplified gene, protein negative] and Calu-3 [HER2 positive (amplified gene, protein positive]. HER2 IHC was performed using a rabbit monoclonal anti-HER2 antibody (clone 4B5 and a conventional 3,3'-diaminobenzidine IHC detection. The HER2 & CEN17 BISH signals were visualized using horseradish peroxidase-based silver and alkaline phosphatase-based red detection systems, respectively with a cocktail of 2,4-dinitrophenyl-labeled HER2 and digoxigenin-labeled CEN17 probes. The performance of the gene-protein assay on tissue microarray slides containing 189 randomly selected FFPE clinical breast cancer tissue cores was compared to that of the separate HER2 IHC and HER2 & CEN17 BISH assays. Results HER2 protein detection was optimal when the HER2 IHC protocol was used before (rather than after the BISH protocol. The sequential use of HER2 IHC and HER2 & CEN17 BISH detection steps on FFPE xenograft tumor sections appropriately co-localized the HER2 protein, HER2 gene, and CEN17 signals after mitigating the silver background staining by using a naphthol phosphate-containing hybridization buffer for the hybridization step. The HER2 protein and HER2 gene status obtained using the multiplex HER2 gene

Profiling gene expression induced by protease-activated receptor 2 (PAR2 activation in human kidney cells.

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Jacky Y Suen

Full Text Available Protease-Activated Receptor-2 (PAR2 has been implicated through genetic knockout mice with cytokine regulation and arthritis development. Many studies have associated PAR2 with inflammatory conditions (arthritis, airways inflammation, IBD and key events in tumor progression (angiogenesis, metastasis, but they have relied heavily on the use of single agonists to identify physiological roles for PAR2. However such probes are now known not to be highly selective for PAR2, and thus precisely what PAR2 does and what mechanisms of downstream regulation are truly affected remain obscure. Effects of PAR2 activation on gene expression in Human Embryonic Kidney cells (HEK293, a commonly studied cell line in PAR2 research, were investigated here by comparing 19,000 human genes for intersecting up- or down-regulation by both trypsin (an endogenous protease that activates PAR2 and a PAR2 activating hexapeptide (2f-LIGRLO-NH(2. Among 2,500 human genes regulated similarly by both agonists, there were clear associations between PAR2 activation and cellular metabolism (1,000 genes, the cell cycle, the MAPK pathway, HDAC and sirtuin enzymes, inflammatory cytokines, and anti-complement function. PAR-2 activation up-regulated four genes more than 5 fold (DUSP6, WWOX, AREG, SERPINB2 and down-regulated another six genes more than 3 fold (TXNIP, RARG, ITGB4, CTSD, MSC and TM4SF15. Both PAR2 and PAR1 activation resulted in up-regulated expression of several genes (CD44, FOSL1, TNFRSF12A, RAB3A, COPEB, CORO1C, THBS1, SDC4 known to be important in cancer. This is the first widespread profiling of specific activation of PAR2 and provides a valuable platform for better understanding key mechanistic roles of PAR2 in human physiology. Results clearly support the development of both antagonists and agonists of human PAR2 as potential disease modifying therapeutic agents.

Identification of a novel Gig2 gene family specific to non-amniote vertebrates.

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Yi-Bing Zhang

Full Text Available Gig2 (grass carp reovirus (GCRV-induced gene 2 is first identified as a novel fish interferon (IFN-stimulated gene (ISG. Overexpression of a zebrafish Gig2 gene can protect cultured fish cells from virus infection. In the present study, we identify a novel gene family that is comprised of genes homologous to the previously characterized Gig2. EST/GSS search and in silico cloning identify 190 Gig2 homologous genes in 51 vertebrate species ranged from lampreys to amphibians. Further large-scale search of vertebrate and invertebrate genome databases indicate that Gig2 gene family is specific to non-amniotes including lampreys, sharks/rays, ray-finned fishes and amphibians. Phylogenetic analysis and synteny analysis reveal lineage-specific expansion of Gig2 gene family and also provide valuable evidence for the fish-specific genome duplication (FSGD hypothesis. Although Gig2 family proteins exhibit no significant sequence similarity to any known proteins, a typical Gig2 protein appears to consist of two conserved parts: an N-terminus that bears very low homology to the catalytic domains of poly(ADP-ribose polymerases (PARPs, and a novel C-terminal domain that is unique to this gene family. Expression profiling of zebrafish Gig2 family genes shows that some duplicate pairs have diverged in function via acquisition of novel spatial and/or temporal expression under stresses. The specificity of this gene family to non-amniotes might contribute to a large extent to distinct physiology in non-amniote vertebrates.

Cooperative Optimization QoS Cloud Routing Protocol Based on Bacterial Opportunistic Foraging and Chemotaxis Perception for Mobile Internet

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Shujuan Wang

2015-01-01

Full Text Available In order to strengthen the mobile Internet mobility management and cloud platform resources utilization, optimizing the cloud routing efficiency is established, based on opportunistic bacterial foraging bionics, and puts forward a chemotaxis perception of collaborative optimization QoS (Quality of Services cloud routing mechanism. The cloud routing mechanism is based on bacterial opportunity to feed and bacterial motility and to establish the data transmission and forwarding of the bacterial population behavior characteristics. This mechanism is based on the characteristics of drug resistance of bacteria and the structure of the field, and through many iterations of the individual behavior and population behavior the bacteria can be spread to the food gathering area with a certain probability. Finally, QoS cloud routing path would be selected and optimized based on bacterial bionic optimization and hedge mapping relationship between mobile Internet node and bacterial population evolution iterations. Experimental results show that, compared with the standard dynamic routing schemes, the proposed scheme has shorter transmission delay, lower packet error ratio, QoS cloud routing loading, and QoS cloud route request overhead.

Genetic Determinants Associated With in Vivo Survival of Burkholderia cenocepacia in the Caenorhabditis elegans Model

KAUST Repository

Wong, Yee-Chin

2018-05-29

A Burkholderia cenocepacia infection usually leads to reduced survival and fatal cepacia syndrome in cystic fibrosis patients. The identification of B. cenocepacia essential genes for in vivo survival is key to designing new anti-infectives therapies. We used the Transposon-Directed Insertion Sequencing (TraDIS) approach to identify genes required for B. cenocepacia survival in the model infection host, Caenorhabditis elegans. A B. cenocepacia J2315 transposon pool of ∼500,000 mutants was used to infect C. elegans. We identified 178 genes as crucial for B. cenocepacia survival in the infected nematode. The majority of these genes code for proteins of unknown function, many of which are encoded by the genomic island BcenGI13, while other gene products are involved in nutrient acquisition, general stress responses and LPS O-antigen biosynthesis. Deletion of the glycosyltransferase gene wbxB and a histone-like nucleoid structuring (H-NS) protein-encoding gene (BCAL0154) reduced bacterial accumulation and attenuated virulence in C. elegans. Further analysis using quantitative RT-PCR indicated that BCAL0154 modulates B. cenocepacia pathogenesis via transcriptional regulation of motility-associated genes including fliC, fliG, flhD, and cheB1. This screen has successfully identified genes required for B. cenocepacia survival within the host-associated environment, many of which are potential targets for developing new antimicrobials.

Genetic Determinants Associated With in Vivo Survival of Burkholderia cenocepacia in the Caenorhabditis elegans Model

KAUST Repository

Wong, Yee-Chin; Abd El Ghany, Moataz; Ghazzali, Raeece N. M.; Yap, Soon-Joo; Hoh, Chee-Choong; Pain, Arnab; Nathan, Sheila

2018-01-01

A Burkholderia cenocepacia infection usually leads to reduced survival and fatal cepacia syndrome in cystic fibrosis patients. The identification of B. cenocepacia essential genes for in vivo survival is key to designing new anti-infectives therapies. We used the Transposon-Directed Insertion Sequencing (TraDIS) approach to identify genes required for B. cenocepacia survival in the model infection host, Caenorhabditis elegans. A B. cenocepacia J2315 transposon pool of ∼500,000 mutants was used to infect C. elegans. We identified 178 genes as crucial for B. cenocepacia survival in the infected nematode. The majority of these genes code for proteins of unknown function, many of which are encoded by the genomic island BcenGI13, while other gene products are involved in nutrient acquisition, general stress responses and LPS O-antigen biosynthesis. Deletion of the glycosyltransferase gene wbxB and a histone-like nucleoid structuring (H-NS) protein-encoding gene (BCAL0154) reduced bacterial accumulation and attenuated virulence in C. elegans. Further analysis using quantitative RT-PCR indicated that BCAL0154 modulates B. cenocepacia pathogenesis via transcriptional regulation of motility-associated genes including fliC, fliG, flhD, and cheB1. This screen has successfully identified genes required for B. cenocepacia survival within the host-associated environment, many of which are potential targets for developing new antimicrobials.

The ULT1 and ULT2 trxG genes play overlapping roles in Arabidopsis development and gene regulation.

Science.gov (United States)

Monfared, Mona M; Carles, Cristel C; Rossignol, Pascale; Pires, Helena R; Fletcher, Jennifer C

2013-09-01

The epigenetic regulation of gene expression is critical for ensuring the proper deployment and stability of defined genome transcription programs at specific developmental stages. The cellular memory of stable gene expression states during animal and plant development is mediated by the opposing activities of Polycomb group (PcG) factors and trithorax group (trxG) factors. Yet, despite their importance, only a few trxG factors have been characterized in plants and their roles in regulating plant development are poorly defined. In this work, we report that the closely related Arabidopsis trxG genes ULTRAPETALA1 (ULT1) and ULT2 have overlapping functions in regulating shoot and floral stem cell accumulation, with ULT1 playing a major role but ULT2 also making a minor contribution. The two genes also have a novel, redundant activity in establishing the apical–basal polarity axis of the gynoecium, indicating that they function in differentiating tissues. Like ULT1 proteins, ULT2 proteins have a dual nuclear and cytoplasmic localization, and the two proteins physically associate in planta. Finally, we demonstrate that ULT1 and ULT2 have very similar overexpression phenotypes and regulate a common set of key development target genes, including floral MADS-box genes and class I KNOX genes. Our results reveal that chromatin remodeling mediated by the ULT1 and ULT2 proteins is necessary to control the development of meristems and reproductive organs. They also suggest that, like their animal counterparts, plant trxG proteins may function in multi-protein complexes to up-regulate the expression of key stage- and tissue-specific developmental regulatory genes.

Feathermoss and epiphytic Nostoc cooperate differently: expanding the spectrum of plant–cyanobacteria symbiosis

Energy Technology Data Exchange (ETDEWEB)

Warshan, Denis; Espinoza, Josh L.; Stuart, Rhona; Richter, Alexander R.; Kim, Sea-Yong; Shapiro, Nicole; Woyke, Tanja; Kyripides, Nikos; Barry, Kerrie W.; Singan, Vasanth; Lindquist, Erika; Ansong, Charles K.; Purvine, Samuel O.; Brewer, Heather M.; Weyman, Philip D.; Dupont, Chris; Rasmussen, Ulla

2017-12-31

Dinitrogen (N2)-fixation by cyanobacteria in symbiosis with feather mosses represents the main pathway of biological N input into boreal forests. Despite its significance, little is known about the gene repertoire needed for the establishment and maintenance of the symbiosis. To determine gene acquisitions or regulatory rewiring allowing cyanobacteria to form this symbiosis, we compared closely related Nostoc strains that were either symbiosis-competent or non-competent, using a proteogenomics approach and a unique experimental setup allowing for controlled chemical and physical contact between partners. Thirty-two protein families were only in the genomes of competent strains, including some never before associated with symbiosis. We identified conserved orthologs that were differentially expressed in competent strains, including gene families involved in chemotaxis and motility, NO regulation, sulfate/phosphate transport, sugar metabolism, and glycosyl-modifying and oxidative stress-mediating exoenzymes. In contrast to other cyanobacteria-plant symbioses, the moss-cyanobacteria epiphytic symbiosis is distinct, with the symbiont retaining motility and chemotaxis, and not modulating N-fixation, photosynthesis, GS-GOGAT cycle, and heterocyst formation. Our work expands our knowledge of plant cyanobacterial symbioses, provides an interaction model of this ecologically significant symbiosis, and suggests new currencies, namely nitric oxide and aliphatic sulfonates, may be involved in establishing and maintaining this symbiosis.

Immune function genes CD99L2, JARID2 and TPO show association with autism spectrum disorder

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Ramos Paula S

2012-06-01

Full Text Available Abstract Background A growing number of clinical and basic research studies have implicated immunological abnormalities as being associated with and potentially responsible for the cognitive and behavioral deficits seen in autism spectrum disorder (ASD children. Here we test the hypothesis that immune-related gene loci are associated with ASD. Findings We identified 2,012 genes of known immune-function via Ingenuity Pathway Analysis. Family-based tests of association were computed on the 22,904 single nucleotide polymorphisms (SNPs from the 2,012 immune-related genes on 1,510 trios available at the Autism Genetic Resource Exchange (AGRE repository. Several SNPs in immune-related genes remained statistically significantly associated with ASD after adjusting for multiple comparisons. Specifically, we observed significant associations in the CD99 molecule-like 2 region (CD99L2, rs11796490, P = 4.01 × 10-06, OR = 0.68 (0.58-0.80, in the jumonji AT rich interactive domain 2 (JARID2 gene (rs13193457, P = 2.71 × 10-06, OR = 0.61 (0.49-0.75, and in the thyroid peroxidase gene (TPO (rs1514687, P = 5.72 × 10-06, OR = 1.46 (1.24-1.72. Conclusions This study suggests that despite the lack of a general enrichment of SNPs in immune function genes in ASD children, several novel genes with known immune functions are associated with ASD.

Selection of reliable reference genes for gene expression studies in Trichoderma afroharzianum LTR-2 under oxalic acid stress.

Science.gov (United States)

Lyu, Yuping; Wu, Xiaoqing; Ren, He; Zhou, Fangyuan; Zhou, Hongzi; Zhang, Xinjian; Yang, Hetong

2017-10-01

An appropriate reference gene is required to get reliable results from gene expression analysis by quantitative real-time reverse transcription PCR (qRT-PCR). In order to identify stable and reliable reference genes in Trichoderma afroharzianum under oxalic acid (OA) stress, six commonly used housekeeping genes, i.e., elongation factor 1, ubiquitin, ubiquitin-conjugating enzyme, glyceraldehyde-3-phosphate dehydrogenase, α-tubulin, actin, from the effective biocontrol isolate T. afroharzianum strain LTR-2 were tested for their expression during growth in liquid culture amended with OA. Four in silico programs (comparative ΔCt, NormFinder, geNorm and BestKeeper) were used to evaluate the expression stabilities of six candidate reference genes. The elongation factor 1 gene EF-1 was identified as the most stably expressed reference gene, and was used as the normalizer to quantify the expression level of the oxalate decarboxylase coding gene OXDC in T. afroharzianum strain LTR-2 under OA stress. The result showed that the expression of OXDC was significantly up-regulated as expected. This study provides an effective method to quantify expression changes of target genes in T. afroharzianum under OA stress. Copyright © 2017 Elsevier B.V. All rights reserved.

Gene conversion and DNA sequence polymorphism in the sex-determination gene fog-2 and its paralog ftr-1 in Caenorhabditis elegans.

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Rane, Hallie S; Smith, Jessica M; Bergthorsson, Ulfar; Katju, Vaishali

2010-07-01

Gene conversion, a form of concerted evolution, bears enormous potential to shape the trajectory of sequence and functional divergence of gene paralogs subsequent to duplication events. fog-2, a sex-determination gene unique to Caenorhabditis elegans and implicated in the origin of hermaphroditism in this species, resulted from the duplication of ftr-1, an upstream gene of unknown function. Synonymous sequence divergence in regions of fog-2 and ftr-1 (excluding recent gene conversion tracts) suggests that the duplication occurred 46 million generations ago. Gene conversion between fog-2 and ftr-1 was previously discovered in experimental fog-2 knockout lines of C. elegans, whereby hermaphroditism was restored in mutant obligately outcrossing male-female populations. We analyzed DNA-sequence variation in fog-2 and ftr-1 within 40 isolates of C. elegans from diverse geographic locations in order to evaluate the contribution of gene conversion to genetic variation in the two gene paralogs. The analysis shows that gene conversion contributes significantly to DNA-sequence diversity in fog-2 and ftr-1 (22% and 34%, respectively) and may have the potential to alter sexual phenotypes in natural populations. A radical amino acid change in a conserved region of the F-box domain of fog-2 was found in natural isolates of C. elegans with significantly lower fecundity. We hypothesize that the lowered fecundity is due to reduced masculinization and less sperm production and that amino acid replacement substitutions and gene conversion in fog-2 may contribute significantly to variation in the degree of inbreeding and outcrossing in natural populations.

Investigation of PAX3/7-FKHR fusion genes and IGF2 gene expression in rhabdomyosarcoma tumors.

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de Souza, Robson Ramos; Oliveira, Indhira Dias; Caran, Eliana Maria Monteiro; Alves, Maria Teresa de Seixas; Abib, Simone; Toledo, Silvia Regina Caminada

2012-12-01

The purpose of our study was to investigate the prevalence of the PAX3/7-FKHR fusion genes and quantify the IGF2 gene expression in rhabdomyosarcoma (RMS) samples. Soft tissue sarcomas account 5% of childhood cancers and 50% of them are RMS. Morphological evaluation of pediatric RMS has defined two histological subtypes, embryonal (ERMS) and alveolar (ARMS). Chromosomal analyses have demonstrated two translocations associated with ARMS, resulting in the PAX3/7-FKHR rearrangements. Reverse transcriptase-polymerase chain reaction (RT-PCR) is extremely useful in the diagnosis of ARMS positive for these rearrangements. Additionally, several studies have shown a significant involvement of IGF pathway in the pathogenesis of RMS. The presence of PAX3/7-FKHR gene fusions was studied in 25 RMS samples from patients attending the IOP-GRAACC/UNIFESP and three RMS cell lines by RT-PCR. IGF2 gene expression was quantified by qPCR and related with clinic pathological parameters. Of the 25 samples, nine (36%) were ARMS and 16 (64%) were ERMS. PAX3/7-FKHR gene fusions expression was detected in 56% of ARMS tumor samples. IGF2 overexpression was observed in 80% of samples and could indicate an important role of this pathway in RMS biology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Bovine CCL28 Mediates Chemotaxis via CCR10 and Demonstrates Direct Antimicrobial Activity against Mastitis Causing Bacteria.

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Kyler B Pallister

Full Text Available In addition to the well characterized function of chemokines in mediating the homing and accumulation of leukocytes to tissues, some chemokines also exhibit potent antimicrobial activity. Little is known of the potential role of chemokines in bovine mammary gland health and disease. The chemokine CCL28 has previously been shown to play a key role in the homing and accumulation of IgA antibody secreting cells to the lactating murine mammary gland. CCL28 has also been shown to act as an antimicrobial peptide with activity demonstrated against a wide range of pathogens including bacteria, fungi and protozoans. Here we describe the cloning and function of bovine CCL28 and document the concentration of this chemokine in bovine milk. Bovine CCL28 was shown to mediate cellular chemotaxis via the CCR10 chemokine receptor and exhibited antimicrobial activity against a variety of bovine mastitis causing organisms. The concentration of bovine CCL28 in milk was found to be highly correlated with the lactation cycle. Highest concentrations of CCL28 were observed soon after parturition, with levels decreasing over time. These results suggest a potential role for CCL28 in the prevention/resolution of bovine mastitis.

A gene-gene interaction between polymorphisms in the OCT2 and MATE1 genes influences the renal clearance of metformin

DEFF Research Database (Denmark)

Hougaard Christensen, Mette Marie; Pedersen, Rasmus Steen; Stage, Tore Bjerregaard

2013-01-01

The aim of this study was to determine the association between the renal clearance (CL(renal)) of metformin in healthy Caucasian volunteers and the single-nucleotide polymorphism (SNP) c.808G>T (rs316019) in OCT2 as well as the relevance of the gene-gene interactions between this SNP and (a) the ...

Molecular characterization, sequence analysis and tissue expression of a porcine gene – MOSPD2

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Yang Jie

2017-01-01

Full Text Available The full-length cDNA sequence of a porcine gene, MOSPD2, was amplified using the rapid amplification of cDNA ends method based on a pig expressed sequence tag sequence which was highly homologous to the coding sequence of the human MOSPD2 gene. Sequence prediction analysis revealed that the open reading frame of this gene encodes a protein of 491 amino acids that has high homology with the motile sperm domain-containing protein 2 (MOSPD2 of five species: horse (89%, human (90%, chimpanzee (89%, rhesus monkey (89% and mouse (85%; thus, it could be defined as a porcine MOSPD2 gene. This novel porcine gene was assigned GeneID: 100153601. This gene is structured in 15 exons and 14 introns as revealed by computer-assisted analysis. The phylogenetic analysis revealed that the porcine MOSPD2 gene has a closer genetic relationship with the MOSPD2 gene of horse. Tissue expression analysis indicated that the porcine MOSPD2 gene is generally and differentially expressed in the spleen, muscle, skin, kidney, lung, liver, fat and heart. Our experiment is the first to establish the primary foundation for further research on the porcine MOSPD2 gene.

Increased expression of ID2, PRELP and SMOC2 genes in patients with endometriosis

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F.M. Araujo

Full Text Available Endometriosis is a benign, estrogen-dependent disease with symptoms such as pelvic pain and infertility, and it is characterized by the ectopic distribution of endometrial tissue. The expression of the ID2, PRELP and SMOC2 genes was compared between the endometrium of women without endometriosis in the proliferative phase of their menstrual cycle and the eutopic and ectopic endometrium of women with endometriosis in the proliferative phase. Paired tissue samples from 20 women were analyzed: 10 from endometrial and peritoneal endometriotic lesions and 10 from endometrial and ovarian endometriotic lesions. As controls, 16 endometrium samples were collected from women without endometriosis in the proliferative phase of menstrual cycle. Analysis was performed by real-time polymerase chain reaction (PCR. There was no significant difference between gene expression in the endometrium of women with and without endometriosis. The ID2 gene expression was increased in the most advanced stage of endometriosis and in ovarian endometriomas, the PRELP was more expressed in peritoneal lesions, and the SMOC2 was highly expressed in both peritoneal and endometrioma lesions. Considering that the genes studied participate either directly or indirectly in cellular processes that can lead to cell migration, angiogenesis, and inappropriate invasion, it is possible that the deregulation of these genes caused the development and maintenance of ectopic tissue.

Acinetobacter baumannii phenylacetic acid metabolism influences infection outcome through a direct effect on neutrophil chemotaxis.

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Bhuiyan, Md Saruar; Ellett, Felix; Murray, Gerald L; Kostoulias, Xenia; Cerqueira, Gustavo M; Schulze, Keith E; Mahamad Maifiah, Mohd Hafidz; Li, Jian; Creek, Darren J; Lieschke, Graham J; Peleg, Anton Y

2016-08-23

Innate cellular immune responses are a critical first-line defense against invading bacterial pathogens. Leukocyte migration from the bloodstream to a site of infection is mediated by chemotactic factors that are often host-derived. More recently, there has been a greater appreciation of the importance of bacterial factors driving neutrophil movement during infection. Here, we describe the development of a zebrafish infection model to study Acinetobacter baumannii pathogenesis. By using isogenic A. baumannii mutants lacking expression of virulence effector proteins, we demonstrated that bacterial drivers of disease severity are conserved between zebrafish and mammals. By using transgenic zebrafish with fluorescent phagocytes, we showed that a mutation of an established A. baumannii global virulence regulator led to marked changes in neutrophil behavior involving rapid neutrophil influx to a localized site of infection, followed by prolonged neutrophil dwelling. This neutrophilic response augmented bacterial clearance and was secondary to an impaired A. baumannii phenylacetic acid catabolism pathway, which led to accumulation of phenylacetate. Purified phenylacetate was confirmed to be a neutrophil chemoattractant. These data identify a previously unknown mechanism of bacterial-guided neutrophil chemotaxis in vivo, providing insight into the role of bacterial metabolism in host innate immune evasion. Furthermore, the work provides a potentially new therapeutic paradigm of targeting a bacterial metabolic pathway to augment host innate immune responses and attenuate disease.

Gene expression profiling in limb-girdle muscular dystrophy 2A.

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Amets Sáenz

Full Text Available Limb-girdle muscular dystrophy type 2A (LGMD2A is a recessive genetic disorder caused by mutations in calpain 3 (CAPN3. Calpain 3 plays different roles in muscular cells, but little is known about its functions or in vivo substrates. The aim of this study was to identify the genes showing an altered expression in LGMD2A patients and the possible pathways they are implicated in. Ten muscle samples from LGMD2A patients with in which molecular diagnosis was ascertained were investigated using array technology to analyze gene expression profiling as compared to ten normal muscle samples. Upregulated genes were mostly those related to extracellular matrix (different collagens, cell adhesion (fibronectin, muscle development (myosins and melusin and signal transduction. It is therefore suggested that different proteins located or participating in the costameric region are implicated in processes regulated by calpain 3 during skeletal muscle development. Genes participating in the ubiquitin proteasome degradation pathway were found to be deregulated in LGMD2A patients, suggesting that regulation of this pathway may be under the control of calpain 3 activity. As frizzled-related protein (FRZB is upregulated in LGMD2A muscle samples, it could be hypothesized that beta-catenin regulation is also altered at the Wnt signaling pathway, leading to an incorrect myogenesis. Conversely, expression of most transcription factor genes was downregulated (MYC, FOS and EGR1. Finally, the upregulation of IL-32 and immunoglobulin genes may induce the eosinophil chemoattraction explaining the inflammatory findings observed in presymptomatic stages. The obtained results try to shed some light on identification of novel therapeutic targets for limb-girdle muscular dystrophies.

Novel Hematopoietic Target Genes in the NRF2-Mediated Transcriptional Pathway

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Michelle R. Campbell

2013-01-01

Full Text Available Nuclear factor- (erythroid-derived 2 like 2 (NFE2L2, NRF2 is a key transcriptional activator of the antioxidant response pathway and is closely related to erythroid transcription factor NFE2. Under oxidative stress, NRF2 heterodimerizes with small Maf proteins and binds cis-acting enhancer sequences found near oxidative stress response genes. Using the dietary isothiocyanate sulforaphane (SFN to activate NRF2, chromatin immunoprecipitation sequencing (ChIP-seq identified several hundred novel NRF2-mediated targets beyond its role in oxidative stress. Activated NRF2 bound the antioxidant response element (ARE in promoters of several known and novel target genes involved in iron homeostasis and heme metabolism, including known targets FTL and FTH1, as well as novel binding in the globin locus control region. Five novel NRF2 target genes were chosen for followup: AMBP, ABCB6, FECH, HRG-1 (SLC48A1, and TBXAS1. SFN-induced gene expression in erythroid K562 and lymphoid cells were compared for each target gene. NRF2 silencing showed reduced expression in lymphoid, lung, and hepatic cells. Furthermore, stable knockdown of NRF2 negative regulator KEAP1 in K562 cells resulted in increased NQO1, AMBP, and TBXAS1 expression. NFE2 binding sites in K562 cells revealed similar binding profiles as lymphoid NRF2 sites in all potential NRF2 candidates supporting a role for NRF2 in heme metabolism and erythropoiesis.

Cloning and molecular evolution of the aldehyde dehydrogenase 2 gene (Aldh2) in bats (Chiroptera).

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Chen, Yao; Shen, Bin; Zhang, Junpeng; Jones, Gareth; He, Guimei

2013-02-01

Old World fruit bats (Pteropodidae) and New World fruit bats (Phyllostomidae) ingest significant quantities of ethanol while foraging. Mitochondrial aldehyde dehydrogenase (ALDH2, encoded by the Aldh2 gene) plays an important role in ethanol metabolism. To test whether the Aldh2 gene has undergone adaptive evolution in frugivorous and nectarivorous bats in relation to ethanol elimination, we sequenced part of the coding region of the gene (1,143 bp, ~73 % coverage) in 14 bat species, including three Old World fruit bats and two New World fruit bats. Our results showed that the Aldh2 coding sequences are highly conserved across all bat species we examined, and no evidence of positive selection was detected in the ancestral branches leading to Old World fruit bats and New World fruit bats. Further research is needed to determine whether other genes involved in ethanol metabolism have been the targets of positive selection in frugivorous and nectarivorous bats.

Sequence analysis of the N-acetyltransferase 2 gene (NAT2) among ...

African Journals Online (AJOL)

Yazun Bashir Jarrar

2017-11-26

Nov 26, 2017 ... Sequence analysis of the N-acetyltransferase 2 gene (NAT2) among Jordanian volunteers. Yazun Bashir Jarrar, Ayat Ahmed Balasmeh and Wassan Jarrar. Department of Pharmacy, College of Pharmacy, AlZaytoonah University of Jordan, Amman, Jordan. ABSTRACT. The present study aimed to identify ...

Analysis of EGFR, HER2, and TOP2A gene status and chromosomal polysomy in gastric adenocarcinoma from Chinese patients

International Nuclear Information System (INIS)

Liang, Zhiyong; Zeng, Xuan; Gao, Jie; Wu, Shafei; Wang, Peng; Shi, Xiaohua; Zhang, Jing; Liu, Tonghua

2008-01-01

The EGFR and HER2 genes are located on chromosomes 7 and 17, respectively. They are therapeutic targets in some tumors. The TOP2A gene, which is located near HER2 on chromosome 17, is the target of many chemotherapeutic agents, and co-amplification of HER2 and TOP2A has been described in several tumor types. Herein, we investigated the gene status of EGFR, HER2, and TOP2A in Chinese gastric carcinoma patients. We determined the rate of polysomy for chromosomes 7 and 17, and we attempted to clarify the relationship between EGFR, HER2, and TOP2A gene copy number and increased expression of their encoded proteins. Furthermore, we tried to address the relationship between alterations in EGFR, HER2, and TOP2A and chromosome polysomy. One hundred cases of formalin fixed and paraffin embedded tumor tissues from Chinese gastric carcinoma patients were investigated by immunohistochemistry and fluorescence in situ hybridization (FISH) methods. Forty-two percent of the cases showed EGFR overexpression; 16% showed EGFR FISH positive; 6% showed HER2 overexpression; and 11% showed HER2 gene amplification, including all six HER2 overexpression cases. TOP2A nuclear staining (nuclear index, NI) was determined in all 100 tumors: NI values ranged from 0.5 – 90%. Three percent of the tumors showed TOP2A gene amplification, which were all accompanied by HER2 gene amplification. Nineteen percent of the tumors showed chromosome 7 polysomy, and 16% showed chromosome 17 polysomy. Chromosome 7 polysomy correlated significantly with EGFR FISH-positivity, but was not associated with EGFR overexpression. HER2 overexpression associated significantly with HER2 gene amplification. TOP2A gene amplification was significantly associated with HER2 gene amplification. No relationship was found between alterations in the EGFR, HER2, and TOP2A genes and clinicopathologic variables of gastric carcinoma. The data from our study suggest that chromosome 7 polysomy may be responsible for increased EGFR

The histone-like protein HU has a role in gene expression during the acid adaptation response in Helicobacter pylori.

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Álvarez, Alhejandra; Toledo, Héctor

2017-08-01

Gastritis, ulcers, and gastric malignancy have been linked to human gastric epithelial colonization by Helicobacter pylori. Characterization of the mechanisms by which H. pylori adapts to the human stomach environment is of crucial importance to understand H. pylori pathogenesis. In an effort to extend our knowledge of these mechanisms, we used proteomic analysis and qRT-PCR to characterize the role of the histone-like protein HU in the response of H. pylori to low pH. Proteomic analysis revealed that genes involved in chemotaxis, oxidative stress, or metabolism are under control of the HU protein. Also, expression of the virulence factors Ggt and NapA is affected by the null mutation of hup gene both at neutral and acid pH, as evidenced by qRT-PCR analysis. Those results showed that H. pylori gene expression is altered by shift to low pH, thus confirming that acid exposure leads to profound changes in genomic expression, and suggest that the HU protein is a regulator that may help the bacterium adapt to the acid stress. In accordance with previous reports, we found that the HU protein participates in gene expression regulation when the microorganism is exposed to acid stress. Such transcriptional regulation underlies protein accumulation in the H. pylori cell. © 2017 John Wiley & Sons Ltd.

Gelatin nanoparticles enhance delivery of hepatitis C virus recombinant NS2 gene.

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Sabet, Salwa; George, Marina A; El-Shorbagy, Haidan M; Bassiony, Heba; Farroh, Khaled Y; Youssef, Tareq; Salaheldin, Taher A

2017-01-01

Development of an effective non-viral vaccine against hepatitis C virus infection is of a great importance. Gelatin nanoparticles (Gel.NPs) have an attention and promising approach as a viable carrier for delivery of vaccine, gene, drug and other biomolecules in the body. The present study aimed to develop stable Gel.NPs conjugated with nonstructural protein 2 (NS2) gene of Hepatitis C Virus genotype 4a (HCV4a) as a safe and an efficient vaccine delivery system. Gel.NPs were synthesized and characterized (size: 150±2 nm and zeta potential +17.6 mv). NS2 gene was successfully cloned and expressed into E. coli M15 using pQE-30 vector. Antigenicity of the recombinant NS2 protein was confirmed by Western blotting to verify the efficiency of NS2 as a possible vaccine. Then NS2 gene was conjugated to gelatin nanoparticles and a successful conjugation was confirmed by labeling and imaging using Confocal Laser Scanning Microscope (CLSM). Interestingly, the transformation of the conjugated NS2/Gel.NPs complex into E. coli DH5-α was 50% more efficient than transformation with the gene alone. In addition, conjugated NS2/Gel.NPs with ratio 1:100 (w/w) showed higher transformation efficiency into E. coli DH5-α than the other ratios (1:50 and 2:50). Gel.NPs effectively enhanced the gene delivery in bacterial cells without affecting the structure of NS2 gene and could be used as a safe, easy, rapid, cost-effective and non-viral vaccine delivery system for HCV.

Heat shock and prolonged heat stress attenuate neurotoxin and sporulation gene expression in group I Clostridium botulinum strain ATCC 3502.

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Selby, Katja; Mascher, Gerald; Somervuo, Panu; Lindström, Miia; Korkeala, Hannu

2017-01-01

Foodborne pathogenic bacteria are exposed to a number of environmental stresses during food processing, storage, and preparation, and in the human body. In order to improve the safety of food, the understanding of molecular stress response mechanisms foodborne pathogens employ is essential. Many response mechanisms that are activated during heat shock may cross-protect bacteria against other environmental stresses. To better understand the molecular mechanisms Clostridium botulinum, the causative agent of botulism, utilizes during acute heat stress and during adaptation to stressfully high temperature, the C. botulinum Group I strain ATCC 3502 was grown in continuous culture at 39°C and exposed to heat shock at 45°C, followed by prolonged heat stress at 45°C to allow adaptation of the culture to the high temperature. Growth in continuous culture was performed to exclude secondary growth phase effects or other environmental impacts on bacterial gene transcription. Changes in global gene expression profiles were studied using DNA microarray hybridization. During acute heat stress, Class I and III heat shock genes as well as members of the SOS regulon were activated. The neurotoxin gene botA and genes encoding the neurotoxin-associated proteins were suppressed throughout the study. Prolonged heat stress led to suppression of the sporulation machinery whereas genes related to chemotaxis and motility were activated. Induced expression of a large proportion of prophage genes was detected, suggesting an important role of acquired genes in the stress resistance of C. botulinum. Finally, changes in the expression of a large number of genes related to carbohydrate and amino acid metabolism indicated remodeling of the cellular metabolism.

Recode-2: new design, new search tools, and many more genes.

LENUS (Irish Health Repository)

Bekaert, Michaël

2010-01-01

\\'Recoding\\' is a term used to describe non-standard read-out of the genetic code, and encompasses such phenomena as programmed ribosomal frameshifting, stop codon readthrough, selenocysteine insertion and translational bypassing. Although only a small proportion of genes utilize recoding in protein synthesis, accurate annotation of \\'recoded\\' genes lags far behind annotation of \\'standard\\' genes. In order to address this issue, provide a service to researchers in the field, and offer training data for developers of gene-annotation software, we have gathered together known cases of recoding within the Recode database. Recode-2 is an improved and updated version of the database. It provides access to detailed information on genes known to utilize translational recoding and allows complex search queries, browsing of recoding data and enhanced visualization of annotated sequence elements. At present, the Recode-2 database stores information on approximately 1500 genes that are known to utilize recoding in their expression--a factor of approximately three increase over the previous version of the database. Recode-2 is available at http:\\/\\/recode.ucc.ie.

Differential hexosamine biosynthetic pathway gene expression with type 2 diabetes

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Megan Coomer

2014-01-01

Full Text Available The hexosamine biosynthetic pathway (HBP culminates in the attachment of O-linked β-N-acetylglucosamine (O-GlcNAc onto serine/threonine residues of target proteins. The HBP is regulated by several modulators, i.e. O-linked β-N-acetylglucosaminyl transferase (OGT and β-N-acetylglucosaminidase (OGA catalyze the addition and removal of O-GlcNAc moieties, respectively; while flux is controlled by the rate-limiting enzyme glutamine:fructose-6-phosphate amidotransferase (GFPT, transcribed by two genes, GFPT1 and GFPT2. Since increased HBP flux is glucose-responsive and linked to insulin resistance/type 2 diabetes onset, we hypothesized that diabetic individuals exhibit differential expression of HBP regulatory genes. Volunteers (n = 60; n = 20 Mixed Ancestry, n = 40 Caucasian were recruited from Stellenbosch and Paarl (Western Cape, South Africa and classified as control, pre- or diabetic according to fasting plasma glucose and HbA1c levels, respectively. RNA was purified from leukocytes isolated from collected blood samples and OGT, OGA, GFPT1 and GFPT2 expressions determined by quantitative real-time PCR. The data reveal lower OGA expression in diabetic individuals (P < 0.01, while pre- and diabetic subjects displayed attenuated OGT expression vs. controls (P < 0.01 and P < 0.001, respectively. Moreover, GFPT2 expression decreased in pre- and diabetic Caucasians vs. controls (P < 0.05 and P < 0.01, respectively. We also found ethnic differences, i.e. Mixed Ancestry individuals exhibited a 2.4-fold increase in GFPT2 expression vs. Caucasians, despite diagnosis (P < 0.01. Gene expression of HBP regulators differs between diabetic and non-diabetic individuals, together with distinct ethnic-specific gene profiles. Thus differential HBP gene regulation may offer diagnostic utility and provide candidate susceptibility genes for different ethnic groupings.

Heterologous expression of wheat VERNALIZATION 2 (TaVRN2 gene in Arabidopsis delays flowering and enhances freezing tolerance.

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Amadou Diallo

Full Text Available The vernalization gene 2 (VRN2, is a major flowering repressor in temperate cereals that is regulated by low temperature and photoperiod. Here we show that the gene from Triticum aestivum (TaVRN2 is also regulated by salt, heat shock, dehydration, wounding and abscissic acid. Promoter analysis indicates that TaVRN2 regulatory region possesses all the specific responsive elements to these stresses. This suggests pleiotropic effects of TaVRN2 in wheat development and adaptability to the environment. To test if TaVRN2 can act as a flowering repressor in species different from the temperate cereals, the gene was ectopically expressed in the model plant Arabidopsis. Transgenic plants showed no alteration in morphology, but their flowering time was significantly delayed compared to controls plants, indicating that TaVRN2, although having no ortholog in Brassicaceae, can act as a flowering repressor in these species. To identify the possible mechanism by which TaVRN2 gene delays flowering in Arabidopsis, the expression level of several genes involved in flowering time regulation was determined. The analysis indicates that the late flowering of the 35S::TaVRN2 plants was associated with a complex pattern of expression of the major flowering control genes, FCA, FLC, FT, FVE and SOC1. This suggests that heterologous expression of TaVRN2 in Arabidopsis can delay flowering by modulating several floral inductive pathways. Furthermore, transgenic plants showed higher freezing tolerance, likely due to the accumulation of CBF2, CBF3 and the COR genes. Overall, our data suggests that TaVRN2 gene could modulate a common regulator of the two interacting pathways that regulate flowering time and the induction of cold tolerance. The results also demonstrate that TaVRN2 could be used to manipulate flowering time and improve cold tolerance in other species.

TINF2 Gene Mutation in a Patient with Pulmonary Fibrosis

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T. W. Hoffman

2016-01-01

Full Text Available Pulmonary fibrosis is a frequent manifestation of telomere syndromes. Telomere gene mutations are found in up to 25% and 3% of patients with familial disease and sporadic disease, respectively. The telomere gene TINF2 encodes an eponymous protein that is part of the shelterin complex, a complex involved in telomere protection and maintenance. A TINF2 gene mutation was recently reported in a family with pulmonary fibrosis. We identified a heterozygous Ser245Tyr mutation in the TINF2 gene of previously healthy female patient that presented with progressive cough due to pulmonary fibrosis as well as panhypogammaglobulinemia at age 52. Retrospective multidisciplinary evaluation classified her as a case of possible idiopathic pulmonary fibrosis. Telomere length-measurement indicated normal telomere length in the peripheral blood compartment. This is the first report of a TINF2 mutation in a patient with sporadic pulmonary fibrosis, which represents another association between TINF2 mutations and this disease. Furthermore, this case underlines the importance of telomere dysfunction and not telomere length alone in telomere syndromes and draws attention to hypogammaglobulinemia as a manifestation of telomere syndromes.

Somatic VHL gene alterations in MEN2-associated medullary thyroid carcinoma

International Nuclear Information System (INIS)

Koch, Christian A; Brouwers, Frederieke M; Vortmeyer, Alexander O; Tannapfel, Andrea; Libutti, Steven K; Zhuang, Zhengping; Pacak, Karel; Neumann, Hartmut PH; Paschke, Ralf

2006-01-01

Germline mutations in RET are responsible for multiple endocrine neoplasia type 2 (MEN2), an autosomal dominantly inherited cancer syndrome that is characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, and parathyroid hyperplasia/adenoma. Recent studies suggest a 'second hit' mechanism resulting in amplification of mutant RET. Somatic VHL gene alterations are implicated in the pathogenesis of MEN2 pheochromocytomas. We hypothesized that somatic VHL gene alterations are also important in the pathogenesis of MEN2-associated MTC. We analyzed 6 MTCs and 1 C-cell hyperplasia (CCH) specimen from 7 patients with MEN2A and RET germline mutations in codons 609, 618, 620, or 634, using microdissection, microsatellite analysis, phosphorimage densitometry, and VHL mutation analysis. First, we searched for allelic imbalance between mutant and wild-type RET by using the polymorphic markers D10S677, D10S1239, and RET on thyroid tissue from these patients. Evidence for RET amplification by this technique could be demonstrated in 3 of 6 MTCs. We then performed LOH analysis using D3S1038 and D3S1110 which map to the VHL gene locus at 3p25/26. VHL gene deletion was present in 3 MTCs. These 3 MTCs also had an allelic imbalance between mutant and wild-type RET. Mutation analysis of the VHL gene showed a somatic frameshift mutation in 1 MTC that also demonstrated LOH at 3p25/26. In the 2 other MTCs with allelic imbalance of RET and somatic VHL gene deletion, no somatic VHL mutation could be detected. The CCH specimen did neither reveal RET imbalance nor somatic VHL gene alterations. These data suggest that a RET germline mutation is necessary for development of CCH, that allelic imbalance between mutant and wild-type RET may set off tumorigenesis, and that somatic VHL gene alterations may not play a major role in tumorigenesis of MEN2A-associated MTC

Association of angiotensin receptor 2 gene polymorphisms with pregnancy induced hypertension risk.

Science.gov (United States)

Li, Chenyang; Peng, Weijun; Zhang, Heng; Yan, Weirong

2018-05-01

To investigate the association of polymorphisms and haplotypes of angiotensin receptor 2 (AT2R) gene with pregnancy induced hypertension (PIH) in Chinese Han women. A case-control study was designed with 446 cases (gestational hypertension, GH: 124; pre-eclampsia, PE + eclampsia, E: 322) and 650 controls. rs5193, rs1403543 and rs12710567 of AT2R gene were genotyped. A logistic regression approach was applied to estimate the relationship between the polymorphisms and haplotypes of AT2Rgene with PIH risk. No relationship between AT2R gene polymorphisms and PIH was detected. The haplotype analysis also showed a negative result. rs5193, rs1403543 and rs12710567 of AT2R gene might have no effect on PIH risk among Chinese Han women.

Hereditary Ovarian Cancer: Not Only BRCA 1 and 2 Genes

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Angela Toss

2015-01-01

Full Text Available More than one-fifth of ovarian tumors have hereditary susceptibility and, in about 65–85% of these cases, the genetic abnormality is a germline mutation in BRCA genes. Nevertheless, several other suppressor genes and oncogenes have been associated with hereditary ovarian cancers, including the mismatch repair (MMR genes in Lynch syndrome, the tumor suppressor gene, TP53, in the Li-Fraumeni syndrome, and several other genes involved in the double-strand breaks repair system, such as CHEK2, RAD51, BRIP1, and PALB2. The study of genetic discriminators and deregulated pathways involved in hereditary ovarian syndromes is relevant for the future development of molecular diagnostic strategies and targeted therapeutic approaches. The recent development and implementation of next-generation sequencing technologies have provided the opportunity to simultaneously analyze multiple cancer susceptibility genes, reduce the delay and costs, and optimize the molecular diagnosis of hereditary tumors. Particularly, the identification of mutations in ovarian cancer susceptibility genes in healthy women may result in a more personalized cancer risk management with tailored clinical and radiological surveillance, chemopreventive approaches, and/or prophylactic surgeries. On the other hand, for ovarian cancer patients, the identification of mutations may provide potential targets for biologic agents and guide treatment decision-making.

Bioinformatics analysis of the factors controlling type I IFN gene expression in autoimmune disease and virus-induced immunity

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Di eFeng

2013-09-01

Full Text Available Patients with systemic lupus erythematosus (SLE and Sjögren's syndrome (SS display increased levels of type I IFN-induced genes. Plasmacytoid dendritic cells (PDCs are natural interferon producing cells and considered to be a primary source of IFN-α in these two diseases. Differential expression patterns of type I IFN inducible transcripts can be found in different immune cell subsets and in patients with both active and inactive autoimmune disease. A type I IFN gene signature generally consists of three groups of IFN-induced genes - those regulated in response to virus-induced type I IFN, those regulated by the IFN-induced mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK pathway, and those by the IFN-induced phosphoinositide-3 kinase (PI-3K pathway. These three groups of type I IFN-regulated genes control important cellular processes such as apoptosis, survival, adhesion, and chemotaxis, that when dysregulated, contribute to autoimmunity. With the recent generation of large datasets in the public domain from next-generation sequencing and DNA microarray experiments, one can perform detailed analyses of cell type-specific gene signatures as well as identify distinct transcription factors that differentially regulate these gene signatures. We have performed bioinformatics analysis of data in the public domain and experimental data from our lab to gain insight into the regulation of type I IFN gene expression. We have found that the genetic landscape of the IFNA and IFNB genes are occupied by transcription factors, such as insulators CTCF and cohesin, that negatively regulate transcription, as well as IRF5 and IRF7, that positively and distinctly regulate IFNA subtypes. A detailed understanding of the factors controlling type I IFN gene transcription will significantly aid in the identification and development of new therapeutic strategies targeting the IFN pathway in autoimmune disease.

Substance-specific importance of EGFR for vascular smooth muscle cells motility in primary culture.

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Schreier, Barbara; Schwerdt, Gerald; Heise, Christian; Bethmann, Daniel; Rabe, Sindy; Mildenberger, Sigrid; Gekle, Michael

2016-07-01

Besides their importance for the vascular tone, vascular smooth muscle cells (VSMC) also contribute to pathophysiological vessel alterations. Various G-protein coupled receptor ligands involved in vascular dysfunction and remodeling can transactivate the epidermal growth factor receptor (EGFR) of VSMC, yet the importance of EGFR transactivation for the VSMC phenotype is incompletely understood. The aims of this study were (i) to characterize further the importance of the VSMC-EGFR for proliferation, migration and marker gene expression for inflammation, fibrosis and reactive oxygen species (ROS) homeostasis and (ii) to test the hypothesis that vasoactive substances (endothelin-1, phenylephrine, thrombin, vasopressin and ATP) rely differentially on the EGFR with respect to the abovementioned phenotypic alterations. In primary, aortic VSMC from mice without conditional deletion of the EGFR, proliferation, migration, marker gene expression (inflammation, fibrosis and ROS homeostasis) and cell signaling (ERK 1/2, intracellular calcium) were analyzed. VSMC-EGFR loss reduced collective cell migration and single cell migration probability, while no difference between the genotypes in single cell velocity, chemotaxis or marker gene expression could be observed under control conditions. EGF promoted proliferation, collective cell migration, chemokinesis and chemotaxis and leads to a proinflammatory gene expression profile in wildtype but not in knockout VSMC. Comparing the impact of five vasoactive substances (all reported to transactivate EGFR and all leading to an EGFR dependent increase in ERK1/2 phosphorylation), we demonstrate that the importance of EGFR for their action is substance-dependent and most apparent for crowd migration but plays a minor role for gene expression regulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Regulation of hepatic PPARγ2 and lipogenic gene expression by melanocortin

International Nuclear Information System (INIS)

Poritsanos, Nicole J.; Wong, Davie; Vrontakis, Maria E.; Mizuno, Tooru M.

2008-01-01

The central melanocortin system regulates hepatic lipid metabolism. Hepatic lipogenic gene expression is regulated by transcription factors including sterol regulatory element-binding protein 1c (SREBP-1c), carbohydrate responsive element-binding protein (ChREBP), and peroxisome proliferator-activated receptor γ2 (PPARγ2). However, it is unclear if central melanocortin signaling regulates hepatic lipogenic gene expression through the activation of these transcription factors. To delineate the molecular mechanisms by which the melanocortin system regulates hepatic lipid metabolism, we examined the effect of intracerebroventricular injection of SHU9119, a melanocortin receptor antagonist, on hepatic expression levels of genes involved in lipid metabolism in mice. SHU9119 treatment increased hepatic triglyceride content and mRNA levels of lipogenic genes, SREBP-1c, and PPARγ2, whereas it did not cause any changes in hepatic ChREBP mRNA levels. These findings suggest that reduced central melanocortin signaling increases hepatic lipid deposition by stimulating hepatic lipogenic gene expression at least partly through the activation of SREBP-1c and PPARγ2

The RNase PD2 gene of almond (Prunus dulcis) represents an evolutionarily distinct class of S-like RNase genes.

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Ma, R C; Oliveira, M M

2000-07-01

A cDNA for an S-like RNase (RNase PD2) has been isolated from a pistil cDNA library of Prunus dulcis cv. Ferragnés. The cDNA encodes an acidic protein of 226 amino acid residues with a molecular weight of 25 kDa. A potential N-glycosylation site is present at the N-terminus in RNase PD2. A signal peptide of 23 amino acid residues and a transmembrane domain are predicted. The two active-site histidines present in enzymes of the T2/S RNase superfamily were detected in RNase PD2. Its amino acid sequence shows 71.2% similarity to RNSI of Arabidopsis and RNase T2 of chickpea, respectively. Northern blotting and RT-PCR analyses indicate that PD2 is expressed predominantly in petals, pistils of open flowers and leaves of the almond tree. Analyses of shoots cultured in vitro suggested that the expression of RNase PD2 is associated with phosphate starvation. Southern analysis detected two sequences related to RNase PD2 in the P. dulcis genome. RFLP analysis showed that S-like RNase genes are polymorphic in different almond cultivars. The PD2 gene sequence was amplified by PCR and two introns were shown to interrupt the coding region. Based on sequence analysis, we have defined three classes of S-like RNase genes, with the PD2 RNase gene representing a distinct class. The significance of the structural divergence of S-like RNase genes is further discussed.

Molecular Evolution and Genetic Variation of G2-Like Transcription Factor Genes in Maize.

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Fang Liu

Full Text Available The productivity of maize (Zea mays L. depends on the development of chloroplasts, and G2-like transcription factors play a central role in regulating chloroplast development. In this study, we identified 59 G2-like genes in the B73 maize genome and systematically analyzed these genes at the molecular and evolutionary levels. Based on gene structure character, motif compositions and phylogenetic analysis, maize G2-like genes (ZmG1- ZmG59 were divided into seven groups (I-VII. By synteny analysis, 18 collinear gene pairs and strongly conserved microsyntny among regions hosting G2-like genes across maize and sorghum were found. Here, we showed that the vast majority of ZmG gene duplications resulted from whole genome duplication events rather than tandem duplications. After gene duplication events, some ZmG genes were silenced. The functions of G2-like genes were multifarious and most genes that are expressed in green tissues may relate to maize photosynthesis. The qRT-PCR showed that the expression of these genes was sensitive to low temperature and drought. Furthermore, we analyzed differences of ZmGs specific to cultivars in temperate and tropical regions at the population level. Interestingly, the single nucleotide polymorphism (SNP analysis revealed that nucleotide polymorphism associated with different temperature zones. Above all, G2-like genes were highly conserved during evolution, but polymorphism could be caused due to a different geographical location. Moreover, G2-like genes might be related to cold and drought stresses.

The organization and expression of the mdm2 gene

Energy Technology Data Exchange (ETDEWEB)

Montes De Oca Luna, R.; Tabor, A.D.; Eberspaecher, H. [Univ. of Texas, Houston, TX (United States)] [and others

1996-05-01

The mdm2 gene encodes a zinc finger protein that negatively regulates p53 function by binding and masking the p53 transcriptional activation domain. Two different promoters control expression of mdm2, one of which is also transactivated by p53. We cloned and characterized the mdm2 gene from a murine 129 library. It contained at least 12 exons and spanned approximately 25 kb of DNA. Sequencing of the mdm2 gene revealed three nucleotide differences that resulted in amino acid substitutions in the previously published mdm2 sequence. Sequences of normal BalbC/J DNA and the original cosmid clone is isolated from the 3T3DM cell line revealed that they are identical, suggesting that the published sequence is in error at these three positions. In addition, we analyzed the expression pattern of mdm2 and found ubiquitous low-level expression throughout embryo development and in adult tissues. Analysis of mRNA from numerous tissues for several mdm2 spliced variants that had been identified in the transformed 3T3DM cell line revealed that these variants could not be detected in the developing embryo or in adult tissues. 25 refs., 3 figs., 2 tabs.

Expression and functional assessment of candidate type 2 diabetes susceptibility genes identify four new genes contributing to human insulin secretion

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Fatou K. Ndiaye

2017-06-01

Full Text Available Objectives: Genome-wide association studies (GWAS have identified >100 loci independently contributing to type 2 diabetes (T2D risk. However, translational implications for precision medicine and for the development of novel treatments have been disappointing, due to poor knowledge of how these loci impact T2D pathophysiology. Here, we aimed to measure the expression of genes located nearby T2D associated signals and to assess their effect on insulin secretion from pancreatic beta cells. Methods: The expression of 104 candidate T2D susceptibility genes was measured in a human multi-tissue panel, through PCR-free expression assay. The effects of the knockdown of beta-cell enriched genes were next investigated on insulin secretion from the human EndoC-βH1 beta-cell line. Finally, we performed RNA-sequencing (RNA-seq so as to assess the pathways affected by the knockdown of the new genes impacting insulin secretion from EndoC-βH1, and we analyzed the expression of the new genes in mouse models with altered pancreatic beta-cell function. Results: We found that the candidate T2D susceptibility genes' expression is significantly enriched in pancreatic beta cells obtained by laser capture microdissection or sorted by flow cytometry and in EndoC-βH1 cells, but not in insulin sensitive tissues. Furthermore, the knockdown of seven T2D-susceptibility genes (CDKN2A, GCK, HNF4A, KCNK16, SLC30A8, TBC1D4, and TCF19 with already known expression and/or function in beta cells changed insulin secretion, supporting our functional approach. We showed first evidence for a role in insulin secretion of four candidate T2D-susceptibility genes (PRC1, SRR, ZFAND3, and ZFAND6 with no previous knowledge of presence and function in beta cells. RNA-seq in EndoC-βH1 cells with decreased expression of PRC1, SRR, ZFAND6, or ZFAND3 identified specific gene networks related to T2D pathophysiology. Finally, a positive correlation between the expression of Ins2 and the

Integration of TP53, DREAM, MMB-FOXM1 and RB-E2F target gene analyses identifies cell cycle gene regulatory networks.

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Fischer, Martin; Grossmann, Patrick; Padi, Megha; DeCaprio, James A

2016-07-27

Cell cycle (CC) and TP53 regulatory networks are frequently deregulated in cancer. While numerous genome-wide studies of TP53 and CC-regulated genes have been performed, significant variation between studies has made it difficult to assess regulation of any given gene of interest. To overcome the limitation of individual studies, we developed a meta-analysis approach to identify high confidence target genes that reflect their frequency of identification in independent datasets. Gene regulatory networks were generated by comparing differential expression of TP53 and CC-regulated genes with chromatin immunoprecipitation studies for TP53, RB1, E2F, DREAM, B-MYB, FOXM1 and MuvB. RNA-seq data from p21-null cells revealed that gene downregulation by TP53 generally requires p21 (CDKN1A). Genes downregulated by TP53 were also identified as CC genes bound by the DREAM complex. The transcription factors RB, E2F1 and E2F7 bind to a subset of DREAM target genes that function in G1/S of the CC while B-MYB, FOXM1 and MuvB control G2/M gene expression. Our approach yields high confidence ranked target gene maps for TP53, DREAM, MMB-FOXM1 and RB-E2F and enables prediction and distinction of CC regulation. A web-based atlas at www.targetgenereg.org enables assessing the regulation of any human gene of interest. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Ndrg2 is a PGC-1α/ERRα target gene that controls protein synthesis and expression of contractile-type genes in C2C12 myotubes.

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Foletta, Victoria C; Brown, Erin L; Cho, Yoshitake; Snow, Rod J; Kralli, Anastasia; Russell, Aaron P

2013-12-01

The stress-responsive, tumor suppressor N-myc downstream-regulated gene 2 (Ndrg2) is highly expressed in striated muscle. In response to anabolic and catabolic signals, Ndrg2 is suppressed and induced, respectively, in mouse C2C12 myotubes. However, little is known about the mechanisms regulating Ndrg2 expression in muscle, as well as the biological role for Ndrg2 in differentiated myotubes. Here, we show that Ndrg2 is a target of a peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) and estrogen-related receptor alpha (ERRα) transcriptional program and is induced in response to endurance exercise, a physiological stress known also to increase PGC-1α/ERRα activity. Analyses of global gene and protein expression profiles in C2C12 myotubes with reduced levels of NDRG2, suggest that NDRG2 affects muscle growth, contractile properties, MAPK signaling, ion and vesicle transport and oxidative phosphorylation. Indeed, suppression of NDRG2 in myotubes increased protein synthesis and the expression of fast glycolytic myosin heavy chain isoforms, while reducing the expression of embryonic myosin Myh3, other contractile-associated genes and the MAPK p90 RSK1. Conversely, enhanced expression of NDRG2 reduced protein synthesis, and furthermore, partially blocked the increased protein synthesis rates elicited by a constitutively active form of ERRα. In contrast, suppressing or increasing levels of NDRG2 did not affect mRNA expression of genes involved in mitochondrial biogenesis that are regulated by PGC-1α or ERRα. This study shows that in C2C12 myotubes Ndrg2 is a novel PGC-1α/ERRα transcriptional target, which influences protein turnover and the regulation of genes involved in muscle contraction and function. © 2013 Elsevier B.V. All rights reserved.

FOXI2: a possible gene contributing to ectodermal dysplasia.

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Kurban, Mazen; Zeineddine, Savo Bou; Hamie, Lamiaa; Safi, Remi; Abbas, Ossama; Kibbi, Abdul Ghani; Bitar, Fadi; Nemer, Georges

2017-12-01

Cardio-facio-cutaneous syndrome (CFC), Noonan syndrome (NS), and Costello syndrome are a group of diseases that belong to the RASopathies. The syndromes share clinical features making diagnosis a challenge. To investigate the phenotype and genotype of a 10-year-old Iraqi girl with overlapping features of CFC, NS, and Costello syndromes, with additional features of ectodermal dysplasia. DNA was examined by exome sequencing and protein expression by immunohistochemistry. Exome sequencing identified a mutation in the SOS1 gene and a de novo deletion in the FOXI2 gene which was neither present in the international databases, nor in 400 chromosomes from the same population. Based on immunohistochemical staining, FOXI2 was identified in the basal cell layer of the skin and overlapped with the expression of P63, a major player in ectodermal dysplasia. We therefore suggest screening for FOXI2 mutation in the setting of ectodermal features that are not associated with genes known to contribute to ectodermal dysplasia.

Nine co-localized cytochrome P450 genes of the CYP2N, CYP2AD, and CYP2P gene families in the mangrove killifish Kryptolebias marmoratus genome: Identification and expression in response to B[α]P, BPA, OP, and NP.

Science.gov (United States)

Puthumana, Jayesh; Kim, Bo-Mi; Jeong, Chang-Bum; Kim, Duck-Hyun; Kang, Hye-Min; Jung, Jee-Hyun; Kim, Il-Chan; Hwang, Un-Ki; Lee, Jae-Seong

2017-06-01

The CYP2 genes are the largest and most diverse cytochrome P450 (CYP) subfamily in vertebrates. We have identified nine co-localized CYP2 genes (∼55kb) in a new cluster in the genome of the highly resilient ecotoxicological fish model Kryptolebias marmoratus. Molecular characterization, temporal and tissue-specific expression pattern, and response to xenobiotics of these genes were examined. The CYP2 gene clusters were characterized and designated CYP2N22-23, CYP2AD12, and CYP2P16-20. Gene synteny analysis confirmed that the cluster in K. marmoratus is similar to that found in other teleost fishes, including zebrafish. A gene duplication event with diverged catalytic function was observed in CYP2AD12. Moreover, a high level of divergence in expression was observed among the co-localized genes. Phylogeny of the cluster suggested an orthologous relationship with similar genes in zebrafish and Japanese medaka. Gene expression analysis showed that CYP2P19 and CYP2N20 were consecutively expressed throughout embryonic development, whereas CYP2P18 was expressed in all adult tissues, suggesting that members of each CYP2 gene family have different physiological roles even though they are located in the same cluster. Among endocrine-disrupting chemicals (EDCs), benzo[α]pyrene (B[α]P) induced expression of CYP2N23, bisphenol A (BPA) induced CYP2P18 and CYP2P19, and 4-octylphenol (OP) induced CYP2AD12, but there was no significant response to 4-nonylphenol (NP), implying differential catalytic roles of the enzyme. In this paper, we identify and characterize a CYP2 gene cluster in the mangrove killifish K. marmoratus with differing catalytic roles toward EDCs. Our findings provide insights on the roles of nine co-localized CYP2 genes and their catalytic functions for better understanding of chemical-biological interactions in fish. Copyright © 2017 Elsevier B.V. All rights reserved.

ABCF2, an Nrf2 target gene, contributes to cisplatin resistance in ovarian cancer cells.

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Bao, Lingjie; Wu, Jianfa; Dodson, Matthew; Rojo de la Vega, Elisa Montserrat; Ning, Yan; Zhang, Zhenbo; Yao, Ming; Zhang, Donna D; Xu, Congjian; Yi, Xiaofang

2017-06-01

Previously, we have demonstrated that NRF2 plays a key role in mediating cisplatin resistance in ovarian cancer. To further explore the mechanism underlying NRF2-dependent cisplatin resistance, we stably overexpressed or knocked down NRF2 in parental and cisplatin-resistant human ovarian cancer cells, respectively. These two pairs of stable cell lines were then subjected to microarray analysis, where we identified 18 putative NRF2 target genes. Among these genes, ABCF2, a cytosolic member of the ABC superfamily of transporters, has previously been reported to contribute to chemoresistance in clear cell ovarian cancer. A detailed analysis on ABCF2 revealed a functional antioxidant response element (ARE) in its promoter region, establishing ABCF2 as an NRF2 target gene. Next, we investigated the contribution of ABCF2 in NRF2-mediated cisplatin resistance using our stable ovarian cancer cell lines. The NRF2-overexpressing cell line, containing high levels of ABCF2, was more resistant to cisplatin-induced apoptosis compared to its control cell line; whereas the NRF2 knockdown cell line with low levels of ABCF2, was more sensitive to cisplatin treatment than its control cell line. Furthermore, transient overexpression of ABCF2 in the parental cells decreased apoptosis and increased cell viability following cisplatin treatment. Conversely, knockdown of ABCF2 using specific siRNA notably increased apoptosis and decreased cell viability in cisplatin-resistant cells treated with cisplatin. This data indicate that the novel NRF2 target gene, ABCF2, plays a critical role in cisplatin resistance in ovarian cancer, and that targeting ABCF2 may be a new strategy to improve chemotherapeutic efficiency. © 2017 Wiley Periodicals, Inc.

HOXB4 Gene Expression Is Regulated by CDX2 in Intestinal Epithelial Cells

DEFF Research Database (Denmark)

Jørgensen, Steffen; Coshun, Mehmet; Mikkelsen Homburg, Keld

2016-01-01

analysis and expression data from Caco2 cells also suggests a role for CDX2 in the regulation of HOXB4 gene expression in the intestinal epithelium. Thus, the aim of this study was to investigate whether HOXB4 gene expression is regulated by CDX2 in the intestinal epithelium. We demonstrated binding of CDX......The mammalian Caudal-related homeobox transcription factor 2 (CDX2) plays a key role in the homeobox regulatory network and is essential in regulating the expression of several homeobox (HOX) genes during embryonic development, particularly in the gut. Genome-wide CDX2 chromatin immunoprecipitation......2 to four different CDX2 binding sites in an enhancer region located upstream of the HOXB4 transcription start site. Mutations in the CDX2 binding sites reduced HOXB4 gene activity, and knock down of endogenous CDX2 expression by shRNA reduced HOXB4 gene expression. This is the first report...

Gene expression profiling following NRF2 and KEAP1 siRNA knockdown in human lung fibroblasts identifies CCL11/Eotaxin-1 as a novel NRF2 regulated gene

Science.gov (United States)

2012-01-01

Background Oxidative Stress contributes to the pathogenesis of many diseases. The NRF2/KEAP1 axis is a key transcriptional regulator of the anti-oxidant response in cells. Nrf2 knockout mice have implicated this pathway in regulating inflammatory airway diseases such as asthma and COPD. To better understand the role the NRF2 pathway has on respiratory disease we have taken a novel approach to define NRF2 dependent gene expression in a relevant lung system. Methods Normal human lung fibroblasts were transfected with siRNA specific for NRF2 or KEAP1. Gene expression changes were measured at 30 and 48 hours using a custom Affymetrix Gene array. Changes in Eotaxin-1 gene expression and protein secretion were further measured under various inflammatory conditions with siRNAs and pharmacological tools. Results An anti-correlated gene set (inversely regulated by NRF2 and KEAP1 RNAi) that reflects specific NRF2 regulated genes was identified. Gene annotations show that NRF2-mediated oxidative stress response is the most significantly regulated pathway, followed by heme metabolism, metabolism of xenobiotics by Cytochrome P450 and O-glycan biosynthesis. Unexpectedly the key eosinophil chemokine Eotaxin-1/CCL11 was found to be up-regulated when NRF2 was inhibited and down-regulated when KEAP1 was inhibited. This transcriptional regulation leads to modulation of Eotaxin-1 secretion from human lung fibroblasts under basal and inflammatory conditions, and is specific to Eotaxin-1 as NRF2 or KEAP1 knockdown had no effect on the secretion of a set of other chemokines and cytokines. Furthermore, the known NRF2 small molecule activators CDDO and Sulphoraphane can also dose dependently inhibit Eotaxin-1 release from human lung fibroblasts. Conclusions These data uncover a previously unknown role for NRF2 in regulating Eotaxin-1 expression and further the mechanistic understanding of this pathway in modulating inflammatory lung disease. PMID:23061798

Novel SNPs polymorphism of bovine CACNA2D1 gene and their ...

African Journals Online (AJOL)

In this study, the bovine CACNA2D1 gene was taken as a candidate gene for mastitis resistance. The objective of this study was to identify single nucleotide polymorphisms (SNPs) in the bovine CACNA2D1 gene and evaluate the association of these SNPs with mastitis in cattle. Through DNA sequencing and PCR-RFLP ...

Genes2WordCloud: a quick way to identify biological themes from gene lists and free text.

Science.gov (United States)

Baroukh, Caroline; Jenkins, Sherry L; Dannenfelser, Ruth; Ma'ayan, Avi

2011-10-13

Word-clouds recently emerged on the web as a solution for quickly summarizing text by maximizing the display of most relevant terms about a specific topic in the minimum amount of space. As biologists are faced with the daunting amount of new research data commonly presented in textual formats, word-clouds can be used to summarize and represent biological and/or biomedical content for various applications. Genes2WordCloud is a web application that enables users to quickly identify biological themes from gene lists and research relevant text by constructing and displaying word-clouds. It provides users with several different options and ideas for the sources that can be used to generate a word-cloud. Different options for rendering and coloring the word-clouds give users the flexibility to quickly generate customized word-clouds of their choice. Genes2WordCloud is a word-cloud generator and a word-cloud viewer that is based on WordCram implemented using Java, Processing, AJAX, mySQL, and PHP. Text is fetched from several sources and then processed to extract the most relevant terms with their computed weights based on word frequencies. Genes2WordCloud is freely available for use online; it is open source software and is available for installation on any web-site along with supporting documentation at http://www.maayanlab.net/G2W. Genes2WordCloud provides a useful way to summarize and visualize large amounts of textual biological data or to find biological themes from several different sources. The open source availability of the software enables users to implement customized word-clouds on their own web-sites and desktop applications.

Exclusion of RAI2 as the causative gene for Nance-Horan syndrome.

Science.gov (United States)

Walpole, S M; Ronce, N; Grayson, C; Dessay, B; Yates, J R; Trump, D; Toutain, A

1999-05-01

Nance-Horan syndrome (NHS) is an X-linked condition characterised by congenital cataracts, microphthalmia and/or microcornea, unusual dental morphology, dysmorphic facial features, and developmental delay in some cases. Recent linkage studies have mapped the NHS disease gene to a 3.5-cM interval on Xp22.2 between DXS1053 and DXS443. We previously identified a human homologue of a mouse retinoic-acid-induced gene (RAI2) within the NHS critical flanking interval and have tested the gene as a candidate for Nance-Horan syndrome in nine NHS-affected families. Direct sequencing of the RAI2 gene and predicted promoter region has revealed no mutations in the families screened; RAI2 is therefore unlikely to be associated with NHS.

Dendritic cells transduced with Rsf-1/HBXAP gene generate specific cytotoxic T lymphocytes against ovarian cancer in vitro

International Nuclear Information System (INIS)

Sun, Li; Kong, Beihua; Sheng, Xiugui; Sheu, Jim Jinn-Chyuan; Shih, Ie-Ming

2010-01-01

Recently, some studies have indicated that Rsf-1/HBXAP plays a role in chromatin remodeling and transcriptional regulation that may contribute to tumorigenesis in ovarian cancer. The present study demonstrates that using dendritic cells (DCs) from human cord blood CD34 + cells transduced with Rsf-1/HBXAP DNA plasmids by nucleofection generate specific cytotoxic T lymphocytes (CTL) against ovarian cancer in vitro. After transfection, DCs were analyzed for Rsf-1/HBXAP mRNA expression by RT-PCR and protein expression by Western blot. Then the DC phenotypes, T-cell stimulatory capacity, endocytic activity and migration capacity were explored by flow cytometry analysis, allogeneic mixed lymphocyte reaction, endocytosis and transwell chemotaxis assay, respectively. After transfection, Rsf-1/HBXAP expression was detected at mRNA and protein levels. Allogeneic T-cell proliferation induced by transfected DCs was obviously higher than non-transfected DCs, but the endocytosis capacity and migratory ability were not different. Rsf-1/HBXAP gene-transduced DCs could induce antigen-specific CTL and generate a very potent cytotoxicity to OVCAR3 cells. These data suggest that Rsf-1/HBXAP gene-transduced DCs may be a potential adjuvant immunotherapy for ovarian cancer in clinical applications.

Association of Forced Vital Capacity with the Developmental Gene NCOR2.

Directory of Open Access Journals (Sweden)

Cosetta Minelli

Full Text Available Forced Vital Capacity (FVC is an important predictor of all-cause mortality in the absence of chronic respiratory conditions. Epidemiological evidence highlights the role of early life factors on adult FVC, pointing to environmental exposures and genes affecting lung development as risk factors for low FVC later in life. Although highly heritable, a small number of genes have been found associated with FVC, and we aimed at identifying further genetic variants by focusing on lung development genes.Per-allele effects of 24,728 SNPs in 403 genes involved in lung development were tested in 7,749 adults from three studies (NFBC1966, ECRHS, EGEA. The most significant SNP for the top 25 genes was followed-up in 46,103 adults (CHARGE and SpiroMeta consortia and 5,062 children (ALSPAC. Associations were considered replicated if the replication p-value survived Bonferroni correction (p<0.002; 0.05/25, with a nominal p-value considered as suggestive evidence. For SNPs with evidence of replication, effects on the expression levels of nearby genes in lung tissue were tested in 1,111 lung samples (Lung eQTL consortium, with further functional investigation performed using public epigenomic profiling data (ENCODE.NCOR2-rs12708369 showed strong replication in children (p = 0.0002, with replication unavailable in adults due to low imputation quality. This intronic variant is in a strong transcriptional enhancer element in lung fibroblasts, but its eQTL effects could not be tested due to low imputation quality in the eQTL dataset. SERPINE2-rs6754561 replicated at nominal level in both adults (p = 0.036 and children (p = 0.045, while WNT16-rs2707469 replicated at nominal level only in adults (p = 0.026. The eQTL analyses showed association of WNT16-rs2707469 with expression levels of the nearby gene CPED1. We found no statistically significant eQTL effects for SERPINE2-rs6754561.We have identified a new gene, NCOR2, in the retinoic acid signalling pathway pointing

USH2A Gene Editing Using the CRISPR System

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Carla Fuster-García

2017-09-01

Full Text Available Usher syndrome (USH is a rare autosomal recessive disease and the most common inherited form of combined visual and hearing impairment. Up to 13 genes are associated with this disorder, with USH2A being the most prevalent, due partially to the recurrence rate of the c.2299delG mutation. Excluding hearing aids or cochlear implants for hearing impairment, there are no medical solutions available to treat USH patients. The repair of specific mutations by gene editing is, therefore, an interesting strategy that can be explored using the CRISPR/Cas9 system. In this study, this method of gene editing is used to target the c.2299delG mutation on fibroblasts from an USH patient carrying the mutation in homozygosis. Successful in vitro mutation repair was demonstrated using locus-specific RNA-Cas9 ribonucleoproteins with subsequent homologous recombination repair induced by an engineered template supply. Effects on predicted off-target sites in the CRISPR-treated cells were discarded after a targeted deep-sequencing screen. The proven effectiveness and specificity of these correction tools, applied to the c.2299delG pathogenic variant of USH2A, indicates that the CRISPR system should be considered to further explore a potential treatment of USH. Keywords: Usher syndrome, USH2A, c.2299delG, CRISPR, gene editing, RNPs

Identification of an ovine atadenovirus gene whose product activates the viral E2 promoter: possible involvement of E2F-1

International Nuclear Information System (INIS)

Kuemin, Daniel; Hofmann, Christian; Uckert, Wolfgang; Both, Gerald W.; Loeser, Peter

2004-01-01

Activation of the adenoviral E2 promoter is an early step in adenovirus gene expression. For members of the mast- and aviadenoviruses, this requires induction of the cellular transcription factor E2F by virally encoded gene products such as E1A, E4orf6/7 and orf22/GAM-1. The newly recognized genus atadenovirus, of which the ovine isolate OAdV is the prototype, lacks any sequence homology to those genes. To find a possible link between E2 promoter activation and OAdV gene expression, we utilized a screening method to search for genes within the OAdV genome that were capable of stimulating the viral E2 promoter. One such gene, E43, was identified within the proposed E4 region toward the right-hand end of the OAdV genome. The E43 gene product was also found to be capable of stimulating E2F-1-dependent gene expression. A closer inspection of the E2 promoter revealed the presence of a non-palindromic E2F binding site within the OAdV E2 promoter. Mutation of this site markedly reduced both E2F-1- and E43-dependent promoter activation. Moreover, a direct protein-protein interaction of the E43 gene product with E2F, but not with the retinoblastoma protein pRb, suggested a possible cooperation between these two proteins in activating the E2 promoter. The importance of the E43 gene product for virus replication is also underlined by the finding that an OAdV recombinant with a functionally inactivated E43 gene showed severely inhibited virus growth

Gene and MicroRNA transcriptome analysis of Parkinson's related LRRK2 mouse models.

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Véronique Dorval

Full Text Available Mutations in leucine-rich repeat kinase 2 (LRRK2 are the most frequent cause of genetic Parkinson's disease (PD. The biological function of LRRK2 and how mutations lead to disease remain poorly defined. It has been proposed that LRRK2 could function in gene transcription regulation; however, this issue remains controversial. Here, we investigated in parallel gene and microRNA (miRNA transcriptome profiles of three different LRRK2 mouse models. Striatal tissue was isolated from adult LRRK2 knockout (KO mice, as well as mice expressing human LRRK2 wildtype (hLRRK2-WT or the PD-associated R1441G mutation (hLRRK2-R1441G. We identified a total of 761 genes and 24 miRNAs that were misregulated in the absence of LRRK2 when a false discovery rate of 0.2 was applied. Notably, most changes in gene expression were modest (i.e., <2 fold. By real-time quantitative RT-PCR, we confirmed the variations of selected genes (e.g., adra2, syt2, opalin and miRNAs (e.g., miR-16, miR-25. Surprisingly, little or no changes in gene expression were observed in mice expressing hLRRK2-WT or hLRRK2-R1441G when compared to non-transgenic controls. Nevertheless, a number of miRNAs were misexpressed in these models. Bioinformatics analysis identified several miRNA-dependent and independent networks dysregulated in LRRK2-deficient mice, including PD-related pathways. These results suggest that brain LRRK2 plays an overall modest role in gene transcription regulation in mammals; however, these effects seem context and RNA type-dependent. Our data thus set the stage for future investigations regarding LRRK2 function in PD development.

Molecular and functional characterization of the promoter of ETS2, the human c-ets-2 gene

International Nuclear Information System (INIS)

Mavrothalassitis, G.J.; Watson, D.K.; Papas, T.S.

1990-01-01

The 5' end of the human c-ets-2 gene, ETS2, was cloned and characterized. The major transcription initiation start sites were identified, and the pertinent sequences surrounding the ETS2 promoter were determined. The promoter region of ETS2 does not possess typical TATA and CAAT elements. However, this promoter contains several repeat regions, as well as two consensus AP2 binding sites and three putative Sp1 sites. There is also a palindromic region similar to the serum response element of the c-fos gene, located 1,400 base pairs (bp) upstream from the first major transcription initiation site. A G+C-rich sequence (GC element) with dyad symmetry can be seen in the ETS2 promoter, immediately following an unusually long polypurine-polypyrimidine tract. A series of deletion fragments from the putative promoter region were ligated in front of the bacterial chloramphenicol acetyltransferase gene and tested for activity following transfection into HeLa cells. The 5' boundary of the region needed for maximum promoter activity was found to be 159 bp upstream of the major initiation site. The promoter of ETS2 (within the polypyrimidine tract) serves to illustrate an alternative structure that may be present in genes with TATA-less promoters

Intestinal PTGS2 mRNA Levels, PTGS2 Gene Polymorphisms, and Colorectal Carcinogenesis

DEFF Research Database (Denmark)

Vogel, Lotte K.; Saebo, Mona; Hoyer, Helle

2014-01-01

Background & Aims: Inflammation is a major risk factor for development of colorectal cancer (CRC). Prostaglandin synthase cyclooxygenase-2 (COX-2) encoded by the PTGS2 gene is the rate limiting enzyme in prostaglandin synthesis and therefore plays a distinct role as regulator of inflammation...

Transcriptional machinery of TNF-α-inducible YTH domain containing 2 (YTHDC2) gene.

Science.gov (United States)

Tanabe, Atsushi; Konno, Junpei; Tanikawa, Kenya; Sahara, Hiroeki

2014-02-01

We previously demonstrated that a cellular factor, cyclosporin A (CsA) associated helicase-like protein (CAHL) that is identical to YTH domain containing 2 (YTHDC2), forms trimer complex with cyclophilin B and NS5B of hepatitis C virus (HCV) and facilitates HCV genome replication. Gene expression of YTHDC2 was shown in tumor cell lines and tumor necrosis factor (TNF)-α-treated hepatocytes, but not in untreated. However, the function of YTHDC2 in the tumor cells and the mechanism by which the YTHDC2 gene is transcribed in these cells is largely unknown. We first evaluated that the role of YTHDC2 in the proliferation of hepatocellular carcinoma (HCC) cell line Huh7 using RNA interference and found that YTHDC2-downregulated Huh7 were significantly decreased cell growth as compared to control. We next demonstrated that the cAMP response element (CRE) site in the promoter region of the YTHDC2 gene is critical for YTHDC2 transcription. To further investigate the transcription factors bound to the CRE site, we performed chromatin immunoprecipitation assays. Our findings demonstrate that c-Jun and ATF-2 bind to the CRE site in Huh7, and that TNF-α induces the biological activity of these transcription factors in hepatocytes as well as Huh7. Moreover, treatment with the HDAC inhibitor, trichostatin A (TSA), reduces YTHDC2 expression in Huh7 and in TNF-α-stimulated hepatocytes. Collectively, these data show that YTHDC2 plays an important role in tumor cells growth and activation/recruitment of c-Jun and ATF-2 to the YTHDC2 promoter is necessary for the transcription of YTHDC2, and that HDAC activity is required for the efficient expression of YTHDC2 in both of hepatocyte and HCC cells. Copyright © 2013 Elsevier B.V. All rights reserved.

NDRG2 gene copy number is not altered in colorectal carcinoma

DEFF Research Database (Denmark)

Lorentzen, Anders Blomkild; Mitchelmore, Cathy

2017-01-01

AIM To investigate if the down-regulation of N-myc Downstream Regulated Gene 2 (NDRG2) expression in colorectal carcinoma (CRC) is due to loss of the NDRG2 allele(s). METHODS The following were investigated in the human colorectal cancer cell lines DLD-1, LoVo and SW-480: NDRG2 mRNA expression...... levels using quantitative reverse transcription-polymerase chain reaction (qRT-PCR); interaction of the MYC gene-regulatory protein with the NDRG2 promoter using chromatin immunoprecipitation; and NDRG2 promoter methylation using bisulfite sequencing. Furthermore, we performed qPCR to analyse the copy...... numbers of NDRG2 and MYC genes in the above three cell lines, 8 normal colorectal tissue samples and 40 CRC tissue samples. RESULTS As expected, NDRG2 mRNA levels were low in the three colorectal cancer cell lines, compared to normal colon. Endogenous MYC protein interacted with the NDRG2 core promoter...

Duplication of the IGFBP-2 gene in teleost fish: protein structure and functionality conservation and gene expression divergence.

Directory of Open Access Journals (Sweden)

Jianfeng Zhou

Full Text Available BACKGROUND: Insulin-like growth factor binding protein-2 (IGFBP-2 is a secreted protein that binds and regulates IGF actions in controlling growth, development, reproduction, and aging. Elevated expression of IGFBP-2 is often associated with progression of many types of cancers. METHODOLOGY/PRINCIPAL FINDINGS: We report the identification and characterization of two IGFBP-2 genes in zebrafish and four other teleost fish. Comparative genomics and structural analyses suggest that they are co-orthologs of the human IGFBP-2 gene. Biochemical assays show that both zebrafish igfbp-2a and -2b encode secreted proteins that bind IGFs. These two genes exhibit distinct spatiotemporal expression patterns. During embryogenesis, IGFBP-2a mRNA is initially detected in the lens, then in the brain boundary vasculature, and subsequently becomes highly expressed in the liver. In the adult stage, liver has the highest levels of IGFBP-2a mRNA, followed by the brain. Low levels of IGFBP-2a mRNA were detected in muscle and in the gonad in male adults only. IGFBP-2b mRNA is detected initially in all tissues at low levels, but later becomes abundant in the liver. In adult males, IGFBP-2b mRNA is only detected in the liver. In adult females, it is also found in the gut, kidney, ovary, and muscle. To gain insights into how the IGFBP-2 genes may have evolved through partitioning of ancestral functions, functional and mechanistic studies were carried out. Expression of zebrafish IGFBP-2a and -2b caused significant decreases in the growth and developmental rates and their effects are comparable to that of human IGFBP-2. IGFBP-2 mutants with altered IGF binding-, RGD-, and heparin-binding sites were generated and their actions examined. While mutating the RGD and heparin binding sites had little effect, altering the IGF binding site abolished its biological activity. CONCLUSIONS/SIGNIFICANCE: These results suggest that IGFBP-2 is a conserved regulatory protein and it inhibits

Genes2WordCloud: a quick way to identify biological themes from gene lists and free text

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Ma'ayan Avi

2011-10-01

Full Text Available Abstract Background Word-clouds recently emerged on the web as a solution for quickly summarizing text by maximizing the display of most relevant terms about a specific topic in the minimum amount of space. As biologists are faced with the daunting amount of new research data commonly presented in textual formats, word-clouds can be used to summarize and represent biological and/or biomedical content for various applications. Results Genes2WordCloud is a web application that enables users to quickly identify biological themes from gene lists and research relevant text by constructing and displaying word-clouds. It provides users with several different options and ideas for the sources that can be used to generate a word-cloud. Different options for rendering and coloring the word-clouds give users the flexibility to quickly generate customized word-clouds of their choice. Methods Genes2WordCloud is a word-cloud generator and a word-cloud viewer that is based on WordCram implemented using Java, Processing, AJAX, mySQL, and PHP. Text is fetched from several sources and then processed to extract the most relevant terms with their computed weights based on word frequencies. Genes2WordCloud is freely available for use online; it is open source software and is available for installation on any web-site along with supporting documentation at http://www.maayanlab.net/G2W. Conclusions Genes2WordCloud provides a useful way to summarize and visualize large amounts of textual biological data or to find biological themes from several different sources. The open source availability of the software enables users to implement customized word-clouds on their own web-sites and desktop applications.

Prevalence of pfhrp2 and pfhrp3 gene deletions in Puerto Lempira, Honduras.

Science.gov (United States)

Abdallah, Joseph F; Okoth, Sheila Akinyi; Fontecha, Gustavo A; Torres, Rosa Elena Mejia; Banegas, Engels I; Matute, María Luisa; Bucheli, Sandra Tamara Mancero; Goldman, Ira F; de Oliveira, Alexandre Macedo; Barnwell, John W; Udhayakumar, Venkatachalam

2015-01-21

Recent studies have demonstrated the deletion of the histidine-rich protein 2 (PfHRP2) gene (pfhrp2) in field isolates of Plasmodium falciparum, which could result in false negative test results when PfHRP2-based rapid diagnostic tests (RDTs) are used for malaria diagnosis. Although primary diagnosis of malaria in Honduras is determined based on microscopy, RDTs may be useful in remote areas. In this study, it was investigated whether there are deletions of the pfhrp2, pfhrp3 and their respective flanking genes in 68 P. falciparum parasite isolates collected from the city of Puerto Lempira, Honduras. In addition, further investigation considered the possible correlation between parasite population structure and the distribution of these gene deletions by genotyping seven neutral microsatellites. Sixty-eight samples used in this study, which were obtained from a previous chloroquine efficacy study, were utilized in the analysis. All samples were genotyped for pfhrp2, pfhrp3 and flanking genes by PCR. The samples were then genotyped for seven neutral microsatellites in order to determine the parasite population structure in Puerto Lempira at the time of sample collection. It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8. However, only 50% of the samples were positive for pfhrp3 and its neighboring genes while the rest were either pfhrp3-negative only or had deleted a combination of pfhrp3 and its neighbouring genes on chromosome 13. Population structure analysis predicted that there are at least two distinct parasite population clusters in this sample population. It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other. The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however

Reactivation of CDX2 in Gastric Cancer as Mark for Gene Silencing Memory

International Nuclear Information System (INIS)

Kameoka, Yuri; Kitazawa, Riko; Ariasu, Kanazu; Tachibana, Ryosuke; Mizuno, Yosuke; Haraguchi, Ryuma; Kitazawa, Sohei

2015-01-01

To explore the epigenetic mechanism that reactivates CDX2 (a homeobox transcription factor that serves as a tumor-suppressor gene) in intestinal-type gastric cancer during cancer progression, we examined the methylation status of the CDX2 gene promoter and the expression pattern of methyl-CpG binding protein-2 (MeCP2). From archives of the pathology records of surgically excised advanced stomach cancer cases in the Department of Molecular Pathology, Ehime University in a past decate (n=265), 10 cases of intestinal-type tubular adenocarcinoma, well-differentiated type (wel) with minor poorly-differentiated adenocarcinoma (por) components were selected. The expression pattern of CDX2, MUC2 and MeCP2 in these 10 cases was analyzed by immunohistochemistry. The cancerous and non-cancerous areas were selectively obtained by microdissection, and the methylation status of the CDX2 promoter of each area was assessed by methylation-specific polymerase chain reaction (MSP). In all 10 cases, CDX2 expression was clearly observed in the nucleus of the non-cancerous background of the intestinal metaplasic area, where the unmethylation pattern of the CDX2 gene promoter prevailed with reduced MeCP2 expression. In this metaplastic area, CDX2 expression was co-localized with its target gene, MUC2. CDX2 expression then disappeared from the deep invasive wel area. Reflecting the reduced CDX2 expression, microdissected samples from all the wel areas showed hypermethylation of the CDX2 gene promoter by MSP, with prominent MeCP2 expression. Interestingly, while hypermethylation of the CDX2 gene promoter was maintained in the por area in 8 of the 10 cases, CDX2 expression was restored in por areas where MeCP2 expression was markedly and selectively reduced. The other two cases, however, showed a constant MeCP2 expression level comparable to the surrounding deep invasive wel area with negative CDX2 expression. Therefore, gene silencing by hypermethylation may be overcome by the reduction of

Evaluation the COL9A2 gene with high myopia

Science.gov (United States)

Zhang, Dingding; Huang, Maomin

2017-11-01

This paper investigates the association of the COL9A2 gene between high myopia and normal controls in the Han Chinese population. It shows that the frameshift mutation (D281fs) in the COL9A2 gene is not associated with high myopia in the Han Chinese population, and the two novel variants(c.143G＞C and c.884G＞A) may contribute to the development of high myopia.

A computational method for the coupled solution of reaction-diffusion equations on evolving domains and manifolds: Application to a model of cell migration and chemotaxis.

Science.gov (United States)

MacDonald, G; Mackenzie, J A; Nolan, M; Insall, R H

2016-03-15

In this paper, we devise a moving mesh finite element method for the approximate solution of coupled bulk-surface reaction-diffusion equations on an evolving two dimensional domain. Fundamental to the success of the method is the robust generation of bulk and surface meshes. For this purpose, we use a novel moving mesh partial differential equation (MMPDE) approach. The developed method is applied to model problems with known analytical solutions; these experiments indicate second-order spatial and temporal accuracy. Coupled bulk-surface problems occur frequently in many areas; in particular, in the modelling of eukaryotic cell migration and chemotaxis. We apply the method to a model of the two-way interaction of a migrating cell in a chemotactic field, where the bulk region corresponds to the extracellular region and the surface to the cell membrane.

Influenza A Virus with a Human-Like N2 Gene Is Circulating in Pigs

DEFF Research Database (Denmark)

Breum, Solvej Østergaard; Hjulsager, Charlotte Kristiane; Trebbien, Ramona

2013-01-01

A novel reassortant influenza A virus, H1avN2hu, has been found in Danish swine. The virus contains an H1 gene similar to the hemagglutinin (HA) gene of H1N1 avian-like swine viruses and an N2 gene most closely related to the neuraminidase (NA) gene of human H3N2 viruses from the mid-1990s....

Breast cancer cells obtain an osteomimetic feature via epithelial-mesenchymal transition that have undergone BMP2/RUNX2 signaling pathway induction.

Science.gov (United States)

Tan, Cong-Cong; Li, Gui-Xi; Tan, Li-Duan; Du, Xin; Li, Xiao-Qing; He, Rui; Wang, Qing-Shan; Feng, Yu-Mei

2016-11-29

Bone is one of the most common organs of breast cancer metastasis. Cancer cells that mimic osteoblasts by expressing bone matrix proteins and factors have a higher likelihood of metastasizing to bone. However, the molecular mechanisms of osteomimicry formation of cancer cells remain undefined. Herein, we identified a set of bone-related genes (BRGs) that are ectopically co-expressed in primary breast cancer tissues and determined that osteomimetic feature is obtained due to the osteoblast-like transformation of epithelial breast cancer cells that have undergone epithelial-mesenchymal transition (EMT) followed by bone morphogenetic protein-2 (BMP2) stimulation. Furthermore, we demonstrated that breast cancer cells that transformed into osteoblast-like cells with high expression of BRGs showed enhanced chemotaxis, adhesion, proliferation and multidrug resistance in an osteoblast-mimic bone microenvironment in vitro. During these processes, runt-related transcription factor 2 (RUNX2) functioned as a master mediator by suppressing or activating the transcription of BRGs that underlie the dynamic antagonism between the TGF-β/SMAD and BMP/SMAD signaling pathways in breast cancer cells. Our findings suggest a novel mechanism of osteomimicry formation that arises in primary breast tumors, which may explain the propensity of breast cancer to metastasize to the skeleton and contribute to potential strategies for predicting and targeting breast cancer bone metastasis and multidrug resistance.

Relocation of a rust resistance gene R 2 and its marker-assisted gene pyramiding in confection sunflower (Helianthus annuus L.).

Science.gov (United States)

Qi, L L; Ma, G J; Long, Y M; Hulke, B S; Gong, L; Markell, S G

2015-03-01

The rust resistance gene R 2 was reassigned to linkage group 14 of the sunflower genome. DNA markers linked to R 2 were identified and used for marker-assisted gene pyramiding in a confection type genetic background. Due to the frequent evolution of new pathogen races, sunflower rust is a recurring threat to sunflower production worldwide. The inbred line Morden Cross 29 (MC29) carries the rust resistance gene, R 2 , conferring resistance to numerous races of rust fungus in the US, Canada, and Australia, and can be used as a broad-spectrum resistance resource. Based on phenotypic assessments and SSR marker analyses on the 117 F2 individuals derived from a cross of HA 89 with MC29 (USDA), R 2 was mapped to linkage group (LG) 14 of the sunflower, and not to the previously reported location on LG9. The closest SSR marker HT567 was located at 4.3 cM distal to R 2 . Furthermore, 36 selected SNP markers from LG14 were used to saturate the R 2 region. Two SNP markers, NSA_002316 and SFW01272, flanked R 2 at a genetic distance of 2.8 and 1.8 cM, respectively. Of the three closely linked markers, SFW00211 amplified an allele specific for the presence of R 2 in a marker validation set of 46 breeding lines, and SFW01272 was also shown to be diagnostic for R 2 . These newly developed markers, together with the previously identified markers linked to the gene R 13a , were used to screen 524 F2 individuals from a cross of a confection R 2 line and HA-R6 carrying R 13a . Eleven homozygous double-resistant F2 plants with the gene combination of R 2 and R 13a were obtained. This double-resistant line will be extremely useful in confection sunflower, where few rust R genes are available, risking evolution of new virulence phenotypes and further disease epidemics.

Systems Analysis of Early Host Gene Expression Provides Clues for Transient Mycobacterium avium ssp avium vs. Persistent Mycobacterium avium ssp paratuberculosis Intestinal Infections.

Science.gov (United States)

Khare, Sangeeta; Drake, Kenneth L; Lawhon, Sara D; Nunes, Jairo E S; Figueiredo, Josely F; Rossetti, Carlos A; Gull, Tamara; Everts, Robin E; Lewin, Harris A; Adams, Leslie Garry

It has long been a quest in ruminants to understand how two very similar mycobacterial species, Mycobacterium avium ssp. paratuberculosis (MAP) and Mycobacterium avium ssp. avium (MAA) lead to either a chronic persistent infection or a rapid-transient infection, respectively. Here, we hypothesized that when the host immune response is activated by MAP or MAA, the outcome of the infection depends on the early activation of signaling molecules and host temporal gene expression. To test our hypothesis, ligated jejuno-ileal loops including Peyer's patches in neonatal calves were inoculated with PBS, MAP, or MAA. A temporal analysis of the host transcriptome profile was conducted at several times post-infection (0.5, 1, 2, 4, 8 and 12 hours). When comparing the transcriptional responses of calves infected with the MAA versus MAP, discordant patterns of mucosal expression were clearly evident, and the numbers of unique transcripts altered were moderately less for MAA-infected tissue than were mucosal tissues infected with the MAP. To interpret these complex data, changes in the gene expression were further analyzed by dynamic Bayesian analysis. Bayesian network modeling identified mechanistic genes, gene-to-gene relationships, pathways and Gene Ontologies (GO) biological processes that are involved in specific cell activation during infection. MAP and MAA had significant different pathway perturbation at 0.5 and 12 hours post inoculation. Inverse processes were observed between MAP and MAA response for epithelial cell proliferation, negative regulation of chemotaxis, cell-cell adhesion mediated by integrin and regulation of cytokine-mediated signaling. MAP inoculated tissue had significantly lower expression of phagocytosis receptors such as mannose receptor and complement receptors. This study reveals that perturbation of genes and cellular pathways during MAP infection resulted in host evasion by mucosal membrane barrier weakening to access entry in the ileum

Myopathic mtDNA Depletion Syndrome Due to Mutation in TK2 Gene.

Science.gov (United States)

Martín-Hernández, Elena; García-Silva, María Teresa; Quijada-Fraile, Pilar; Rodríguez-García, María Elena; Rivera, Henry; Hernández-Laín, Aurelio; Coca-Robinot, David; Fernández-Toral, Joaquín; Arenas, Joaquín; Martín, Miguel A; Martínez-Azorín, Francisco

2017-01-01

Whole-exome sequencing was used to identify the disease gene(s) in a Spanish girl with failure to thrive, muscle weakness, mild facial weakness, elevated creatine kinase, deficiency of mitochondrial complex III and depletion of mtDNA. With whole-exome sequencing data, it was possible to get the whole mtDNA sequencing and discard any pathogenic variant in this genome. The analysis of whole exome uncovered a homozygous pathogenic mutation in thymidine kinase 2 gene ( TK2; NM_004614.4:c.323 C>T, p.T108M). TK2 mutations have been identified mainly in patients with the myopathic form of mtDNA depletion syndromes. This patient presents an atypical TK2-related myopathic form of mtDNA depletion syndromes, because despite having a very low content of mtDNA (TK2 gene in mtDNA depletion syndromes and expanded the phenotypic spectrum.

Common variants at the CHEK2 gene locus and risk of epithelial ovarian cancer

DEFF Research Database (Denmark)

Lawrenson, Kate; Iversen, Edwin S; Tyrer, Jonathan

2015-01-01

genes and EOC risk. We genotyped 2896 common variants at 143 gene loci in DNA samples from 15 397 patients with invasive EOC and controls. We found evidence of associations with EOC risk for variants at FANCA, EXO1, E2F4, E2F2, CREB5 and CHEK2 genes (P ≤ 0.001). The strongest risk association......, CHEK2 gene expression was significantly higher in primary EOCs compared to normal fallopian tube tissues (P = 3.72×10(-8)). We also identified an association between genotypes of the candidate causal SNP rs12166475 (r (2) = 0.99 with rs6005807) and CHEK2 expression (P = 2.70×10(-8)). These data suggest...... that common variants at 22q12.1 are associated with risk of serous EOC and CHEK2 as a plausible target susceptibility gene....

Cloning and characterization of the major histone H2A genes completes the cloning and sequencing of known histone genes of Tetrahymena thermophila.

Science.gov (United States)

Liu, X; Gorovsky, M A

1996-01-01

A truncated cDNA clone encoding Tetrahymena thermophila histone H2A2 was isolated using synthetic degenerate oligonucleotide probes derived from H2A protein sequences of Tetrahymena pyriformis. The cDNA clone was used as a homologous probe to isolate a truncated genomic clone encoding H2A1. The remaining regions of the genes for H2A1 (HTA1) and H2A2 (HTA2) were then isolated using inverse PCR on circularized genomic DNA fragments. These partial clones were assembled into intact HTA1 and HTA2 clones. Nucleotide sequences of the two genes were highly homologous within the coding region but not in the noncoding regions. Comparison of the deduced amino acid sequences with protein sequences of T. pyriformis H2As showed only two and three differences respectively, in a total of 137 amino acids for H2A1, and 132 amino acids for H2A2, indicating the two genes arose before the divergence of these two species. The HTA2 gene contains a TAA triplet within the coding region, encoding a glutamine residue. In contrast with the T. thermophila HHO and HTA3 genes, no introns were identified within the two genes. The 5'- and 3'-ends of the histone H2A mRNAs; were determined by RNase protection and by PCR mapping using RACE and RLM-RACE methods. Both genes encode polyadenylated mRNAs and are highly expressed in vegetatively growing cells but only weakly expressed in starved cultures. With the inclusion of these two genes, T. thermophila is the first organism whose entire complement of known core and linker histones, including replication-dependent and basal variants, has been cloned and sequenced. PMID:8760889

Natural variation of rice blast resistance gene Pi-d2

Science.gov (United States)

Studying natural variation of rice resistance (R) genes in cultivated and wild rice relatives can predict resistance stability to rice blast fungus. In the present study, the protein coding regions of rice R gene Pi-d2 in 35 rice accessions of subgroups, aus (AUS), indica (IND), temperate japonica (...

Hemoglobin alpha 2 gene +861 G>A polymorphism in Turkish ...

African Journals Online (AJOL)

Dilay Ciglidag Dungul

carrying individuals with intact beta globin gene. DNA was extracted from peripheral blood sam- ples of seven healthy carrier individuals who have abnormal hemoglobin variants and 16 control individuals from Turkey. Complete coding and intronic sequences of HBA1 and HBA2 genes were amplified by polymerase chain ...

Mutations of dual oxidase 2 (DUOX2) gene among patients with permanent and transient congenital hypothyroidism

International Nuclear Information System (INIS)

Rostampour, N.; Tajaddini, M.H.; Hashemipour, M

2012-01-01

Objective: The prevalence of congenital hypothyroidism (CH) is high in Isfahan, Iran. In addition, it has different etiologies compared with other countries. The rate of parental consanguinity is also high in the city. Moreover, DUOX2 gene is effective in transient CH and permanent CH due to dyshormonogenesis. Therefore, the aim of this research was to investigate the mutations of DUOX2 gene in patients with transient CH and permanent CH due to dyshormonogenesis. Methodology: In this descriptive, prospective study, patients diagnosed with transient and permanent CH due to dyshormonogenesis during CH screening program were selected. Venous blood samples were obtained to determine the 3 mutations (Q36H, R376W, and D506N) of DUOX2 gene using polymerase chain reaction (PCR) method by specific primers and complementary methods such as restriction fragment length polymorphism (RFLP) and single-strand conformation polymorphism (SSCP). Results: In this study, 25 patients with transient CH and 33 subjects with permanent CH due to dyshormonogenesis were studied. In addition, 30 children were studied as the control group. We did not find any mutations of the 3 mentioned mutations of DUOX2 gene. Conclusion: Considering the findings of the current study, further studies with other methods are required to evaluate other gene mutations such as pendrin, sodium-iodide symporter (NIS) and thyroglobulin. (author)

Array2BIO: from microarray expression data to functional annotation of co-regulated genes

Directory of Open Access Journals (Sweden)

Rasley Amy

2006-06-01

Full Text Available Abstract Background There are several isolated tools for partial analysis of microarray expression data. To provide an integrative, easy-to-use and automated toolkit for the analysis of Affymetrix microarray expression data we have developed Array2BIO, an application that couples several analytical methods into a single web based utility. Results Array2BIO converts raw intensities into probe expression values, automatically maps those to genes, and subsequently identifies groups of co-expressed genes using two complementary approaches: (1 comparative analysis of signal versus control and (2 clustering analysis of gene expression across different conditions. The identified genes are assigned to functional categories based on Gene Ontology classification and KEGG protein interaction pathways. Array2BIO reliably handles low-expressor genes and provides a set of statistical methods for quantifying expression levels, including Benjamini-Hochberg and Bonferroni multiple testing corrections. An automated interface with the ECR Browser provides evolutionary conservation analysis for the identified gene loci while the interconnection with Crème allows prediction of gene regulatory elements that underlie observed expression patterns. Conclusion We have developed Array2BIO – a web based tool for rapid comprehensive analysis of Affymetrix microarray expression data, which also allows users to link expression data to Dcode.org comparative genomics tools and integrates a system for translating co-expression data into mechanisms of gene co-regulation. Array2BIO is publicly available at http://array2bio.dcode.org.

Intratumoral Immunization by p19Arf and Interferon-β Gene Transfer in a Heterotopic Mouse Model of Lung Carcinoma

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João Paulo Portela Catani

2016-12-01

Full Text Available Therapeutic strategies that act by eliciting and enhancing antitumor immunity have been clinically validated as an effective treatment modality but may benefit from the induction of both cell death and immune activation as primary stimuli. Using our AdRGD-PG adenovector platform, we show here for the first time that in situ gene transfer of p19Arf and interferon-β (IFNβ in the LLC1 mouse model of lung carcinoma acts as an immunotherapy. Although p19Arf is sufficient to induce cell death, only its pairing with IFNβ significantly induced markers of immunogenic cell death. In situ gene therapy with IFNβ, either alone or in combination with p19Arf, could retard tumor progression, but only the combined treatment was associated with a protective immune response. Specifically in the case of combined intratumoral gene transfer, we identified 167 differentially expressed genes when using microarray to evaluate tumors that were treated in vivo and confirmed the activation of CCL3, CXCL3, IL1α, IL1β, CD274, and OSM, involved in immune response and chemotaxis. Histologic evaluation revealed significant tumor infiltration by neutrophils, whereas functional depletion of granulocytes ablated the antitumor effect of our approach. The association of in situ gene therapy with cisplatin resulted in synergistic elimination of tumor progression. In all, in situ gene transfer with p19Arf and IFNβ acts as an immunotherapy involving recruitment of neutrophils, a desirable but previously untested outcome, and this approach may be allied with chemotherapy, thus providing significant antitumor activity and warranting further development for the treatment of lung carcinoma.

Association of −330 interleukin-2 gene polymorphism with oral cancer

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Prithvi Kumar Singh

2017-01-01

>Results: IL-2 (−330A>C gene polymorphism was significantly associated with oral cancer whereas it was neither associated with clinicopathological status nor with cancer pain. The AC heterozygous genotype was significantly associated with oral cancer patients as compared to controls [odds ratio (OR: 3.0; confidence interval (CI: 2.14-4.20; PC gene polymorphism was also associated with oral cancer in tobacco smokers and chewers. >Interpretation & conclusions: Our results showed that oral cancer patients had significantly higher frequency of AA genotype but significantly lower frequency of AC genotype and C allele compared to controls. The IL-2 AC genotype and C allele of IL-2 (−330A>C gene polymorphisms could be potential protective factors and might reduce the risk of oral cancer in Indian population.

TBC2target: A Resource of Predicted Target Genes of Tea Bioactive Compounds

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Shihua Zhang

2018-02-01

Full Text Available Tea is one of the most popular non-alcoholic beverages consumed worldwide. Numerous bioactive constituents of tea were confirmed to possess healthy benefits via the mechanisms of regulating gene expressions or protein activities. However, a complete interacting profile between tea bioactive compounds (TBCs and their target genes is lacking, which put an obstacle in the study of healthy function of tea. To fill this gap, we developed a database of target genes of TBCs (TBC2target, http://camellia.ahau.edu.cn/TBC2target based on a pharmacophore mapping approach. In TBC2target, 6,226 interactions between 240 TBCs and 673 target genes were documented. TBC2target contains detailed information about each interacting entry, such as TBC, CAS number, PubChem CID, source of compound (e.g., green, black, compound type, target gene(s of TBC, gene symbol, gene ID, ENSEMBL ID, PDB ID, TBC bioactivity and the reference. Using the TBC-target associations, we constructed a bipartite network and provided users the global network and local sub-network visualization and topological analyses. The entire database is free for online browsing, searching and downloading. In addition, TBC2target provides a BLAST search function to facilitate use of the database. The particular strengths of TBC2target are the inclusion of the comprehensive TBC-target interactions, and the capacity to visualize and analyze the interacting networks, which may help uncovering the beneficial effects of tea on human health as a central resource in tea health community.

TBC2target: A Resource of Predicted Target Genes of Tea Bioactive Compounds.

Science.gov (United States)

Zhang, Shihua; Zhang, Liang; Wang, Yijun; Yang, Jian; Liao, Mingzhi; Bi, Shoudong; Xie, Zhongwen; Ho, Chi-Tang; Wan, Xiaochun

2018-01-01

Tea is one of the most popular non-alcoholic beverages consumed worldwide. Numerous bioactive constituents of tea were confirmed to possess healthy benefits via the mechanisms of regulating gene expressions or protein activities. However, a complete interacting profile between tea bioactive compounds (TBCs) and their target genes is lacking, which put an obstacle in the study of healthy function of tea. To fill this gap, we developed a database of target genes of TBCs (TBC2target, http://camellia.ahau.edu.cn/TBC2target) based on a pharmacophore mapping approach. In TBC2target, 6,226 interactions between 240 TBCs and 673 target genes were documented. TBC2target contains detailed information about each interacting entry, such as TBC, CAS number, PubChem CID, source of compound (e.g., green, black), compound type, target gene(s) of TBC, gene symbol, gene ID, ENSEMBL ID, PDB ID, TBC bioactivity and the reference. Using the TBC-target associations, we constructed a bipartite network and provided users the global network and local sub-network visualization and topological analyses. The entire database is free for online browsing, searching and downloading. In addition, TBC2target provides a BLAST search function to facilitate use of the database. The particular strengths of TBC2target are the inclusion of the comprehensive TBC-target interactions, and the capacity to visualize and analyze the interacting networks, which may help uncovering the beneficial effects of tea on human health as a central resource in tea health community.

Chromosome locations of genes encoding human signal transduction adapter proteins, Nck (NCK), Shc (SHC1), and Grb2 (GRB2)

DEFF Research Database (Denmark)

Huebner, K; Kastury, K; Druck, T

1994-01-01

"adapter" proteins, which are involved in transducing signals from receptor tyrosine kinases to downstream signal recipients such as ras, because adaptor protein genes could also, logically, serve as targets of mutation, rearrangement, or other aberration in disease. Therefore, DNAs from panels of rodent-human......Abnormalities due to chromosomal aberration or point mutation in gene products of growth factor receptors or in ras gene products, which lie on the same signaling pathway, can cause disease in animals and humans. Thus, it can be important to determine chromosomal map positions of genes encoding...... hybrids carrying defined complements of human chromosomes were assayed for the presence of the cognate genes for NCK, SHC, and GRB2, three SH2 or SH2/SH3 (Src homology 2 and 3) domain-containing adapter proteins. Additionally, NCK and SHC genes were more narrowly localized by chromosomal in situ...

Global map of physical interactions among differentially expressed genes in multiple sclerosis relapses and remissions.

Science.gov (United States)

Tuller, Tamir; Atar, Shimshi; Ruppin, Eytan; Gurevich, Michael; Achiron, Anat

2011-09-15

Multiple sclerosis (MS) is a central nervous system autoimmune inflammatory T-cell-mediated disease with a relapsing-remitting course in the majority of patients. In this study, we performed a high-resolution systems biology analysis of gene expression and physical interactions in MS relapse and remission. To this end, we integrated 164 large-scale measurements of gene expression in peripheral blood mononuclear cells of MS patients in relapse or remission and healthy subjects, with large-scale information about the physical interactions between these genes obtained from public databases. These data were analyzed with a variety of computational methods. We find that there is a clear and significant global network-level signal that is related to the changes in gene expression of MS patients in comparison to healthy subjects. However, despite the clear differences in the clinical symptoms of MS patients in relapse versus remission, the network level signal is weaker when comparing patients in these two stages of the disease. This result suggests that most of the genes have relatively similar expression levels in the two stages of the disease. In accordance with previous studies, we found that the pathways related to regulation of cell death, chemotaxis and inflammatory response are differentially expressed in the disease in comparison to healthy subjects, while pathways related to cell adhesion, cell migration and cell-cell signaling are activated in relapse in comparison to remission. However, the current study includes a detailed report of the exact set of genes involved in these pathways and the interactions between them. For example, we found that the genes TP53 and IL1 are 'network-hub' that interacts with many of the differentially expressed genes in MS patients versus healthy subjects, and the epidermal growth factor receptor is a 'network-hub' in the case of MS patients with relapse versus remission. The statistical approaches employed in this study enabled us

Functional role of DNA mismatch repair gene PMS2 in prostate cancer cells.

Science.gov (United States)

Fukuhara, Shinichiro; Chang, Inik; Mitsui, Yozo; Chiyomaru, Takeshi; Yamamura, Soichiro; Majid, Shahana; Saini, Sharanjot; Deng, Guoren; Gill, Ankurpreet; Wong, Darryn K; Shiina, Hiroaki; Nonomura, Norio; Lau, Yun-Fai C; Dahiya, Rajvir; Tanaka, Yuichiro

2015-06-30

DNA mismatch repair (MMR) enzymes act as proofreading complexes that maintains genomic integrity and MMR-deficient cells show an increased mutation rate. MMR has also been shown to influence cell signaling and the regulation of tumor development. MMR consists of various genes and includes post-meiotic segregation (PMS) 2 which is a vital component of mutL-alpha. In prostate, the functional role of this gene has never been reported and in this study, our aim was to investigate the effect of PMS2 on growth properties of prostate cancer (PCa) cells. Previous studies have shown PMS2 to be deficient in DU145 cells and this lack of expression was confirmed by Western blotting whereas normal prostatic PWR-1E and RWPE-1 cells expressed this gene. PMS2 effects on various growth properties of DU145 were then determined by creating stable gene transfectants. Interestingly, PMS2 caused decreased cell proliferation, migration, invasion, and in vivo growth; and increased apoptosis as compared to vector control. We further analyzed genes affected by PMS2 expression and observe the apoptosis-related TMS1 gene to be significantly upregulated whereas anti-apoptotic BCL2A1 was downregulated. These results demonstrate a functional role for PMS2 to protect against PCa progression by enhancing apoptosis of PCa cells.

TMPRSS2-ERG gene fusions are infrequent in prostatic ductal adenocarcinomas.

Science.gov (United States)

Lotan, Tamara L; Toubaji, Antoun; Albadine, Roula; Latour, Mathieu; Herawi, Mehsati; Meeker, Alan K; DeMarzo, Angelo M; Platz, Elizabeth A; Epstein, Jonathan I; Netto, George J

2009-03-01

Ductal adenocarcinoma of the prostate is an unusual subtype that may be associated with a more aggressive clinical course, and is less responsive to conventional therapies than the more common prostatic acinar adenocarcinoma. However, given its frequent association with an acinar component at prostatectomy, some have challenged the concept of prostatic ductal adenocarcinoma as a distinct clinicopathologic entity. We studied the occurrence of the TMPRSS2-ERG gene fusion, in 40 surgically resected ductal adenocarcinoma cases, and in their associated acinar component using fluorescence in situ hybridization. A group of 38 'pure' acinar adenocarcinoma cases matched with the ductal adenocarcinoma group for pathological grade and stage was studied as a control. Compared with the matched acinar adenocarcinoma cases, the TMPRSS2-ERG gene fusion was significantly less frequently observed in ductal adenocarcinoma (45 vs 11% of cases, P=0.002, Fisher's exact test). Here, of the ductal adenocarcinoma cases with the gene fusion, 75% were fused through deletion, and the remaining case was fused through translocation. The TMPRSS2-ERG gene fusion was also rare in the acinar component of mixed ductal-acinar tumors when compared with the pure acinar adenocarcinoma controls (5 vs 45%, P=0.001, Fisher's exact test). In 95% of the ductal adenocarcinoma cases in which a concurrent acinar component was analyzed, there was concordance for presence/absence of the TMPRSS2-ERG gene fusion between the different histologic subtypes. In the control group of pure acinar adenocarcinoma cases, 59% were fused through deletion and 41% were fused through translocation. The presence of the TMPRSS2-ERG gene fusion in some cases of prostatic ductal adenocarcinoma supports the concept that ductal adenocarcinoma and acinar adenocarcinoma may be related genetically. However, the significantly lower rate of the gene fusion in pure ductal adenocarcinoma cases underscores the fact that genetic and biologic

ABCG2 in peptic ulcer: gene expression and mutation analysis.

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Salagacka-Kubiak, Aleksandra; Żebrowska, Marta; Wosiak, Agnieszka; Balcerczak, Mariusz; Mirowski, Marek; Balcerczak, Ewa

2016-08-01

The aim of this study was to evaluate the participation of polymorphism at position C421A and mRNA expression of the ABCG2 gene in the development of peptic ulcers, which is a very common and severe disease. ABCG2, encoded by the ABCG2 gene, has been found inter alia in the gastrointestinal tract, where it plays a protective role eliminating xenobiotics from cells into the extracellular environment. The materials for the study were biopsies of gastric mucosa taken during a routine endoscopy. For genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) at position C421A, DNA was isolated from 201 samples, while for the mRNA expression level by real-time PCR, RNA was isolated from 60 patients. The control group of healthy individuals consisted of 97 blood donors. The dominant genotype in the group of peptic ulcer patients and healthy individuals was homozygous CC. No statistically significant differences between healthy individuals and the whole group of peptic ulcer patients and, likewise, between the subgroups of peptic ulcer patients (infected and uninfected with Helicobacter pylori) were found. ABCG2 expression relative to GAPDH expression was found in 38 of the 60 gastric mucosa samples. The expression level of the gene varies greatly among cases. The statistically significant differences between the intensity (p = 0.0375) of H. pylori infection and ABCG2 gene expression have been shown. It was observed that the more intense the infection, the higher the level of ABCG2 expression.

Hemoglobin alpha 2 gene +861 G>A polymorphism in Turkish ...

African Journals Online (AJOL)

Thalassemia is an inherited blood disorder which is divided into two groups: alpha and beta. HBA1 and HBA2 are the two genes associated with alpha thalassemia. The aim of this study is to investigate abnormal hemoglobin variants of alpha globin gene in healthy abnormal hemoglobin carrying individuals with intact beta ...

AP-2α and AP-2β cooperatively orchestrate homeobox gene expression during branchial arch patterning.

Science.gov (United States)

Van Otterloo, Eric; Li, Hong; Jones, Kenneth L; Williams, Trevor

2018-01-25

The evolution of a hinged moveable jaw with variable morphology is considered a major factor behind the successful expansion of the vertebrates. DLX homeobox transcription factors are crucial for establishing the positional code that patterns the mandible, maxilla and intervening hinge domain, but how the genes encoding these proteins are regulated remains unclear. Herein, we demonstrate that the concerted action of the AP-2α and AP-2β transcription factors within the mouse neural crest is essential for jaw patterning. In the absence of these two proteins, the hinge domain is lost and there are alterations in the size and patterning of the jaws correlating with dysregulation of homeobox gene expression, with reduced levels of Emx, Msx and Dlx paralogs accompanied by an expansion of Six1 expression. Moreover, detailed analysis of morphological features and gene expression changes indicate significant overlap with various compound Dlx gene mutants. Together, these findings reveal that the AP-2 genes have a major function in mammalian neural crest development, influencing patterning of the craniofacial skeleton via the DLX code, an effect that has implications for vertebrate facial evolution, as well as for human craniofacial disorders. © 2018. Published by The Company of Biologists Ltd.

Understanding the links among neuromedin U gene, beta2-adrenoceptor gene and bone health: an observational study in European children.

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Francesco Gianfagna

Full Text Available Neuromedin U, encoded by the NMU gene, is a hypothalamic neuropeptide that regulates both energy metabolism and bone mass. The beta-2 adrenergic receptor, encoded by the ADRB2 gene, mediates several effects of catecholamine hormones and neurotransmitters in bone. We investigated whether NMU single nucleotide polymorphisms (SNPs and haplotypes, as well as functional ADRB2 SNPs, are associated with bone stiffness in children from the IDEFICS cohort, also evaluating whether NMU and ADRB2 interact to affect this trait. A sample of 2,274 subjects (52.5% boys, age 6.2 ± 1.8 years from eight European countries, having data on calcaneus bone stiffness index (SI, mean of both feet and genotyping (NMU gene: rs6827359, rs12500837, rs9999653; ADRB2 gene: rs1042713, rs1042714, was studied. After false discovery rate adjustment, SI was significantly associated with all NMU SNPs. rs6827359 CC homozygotes showed the strongest association (recessive model, Δ= -1.8, p=0.006. Among the five retrieved haplotypes with frequencies higher than 1% (range 2.0-43.9%, the CCT haplotype (frequency=39.7% was associated with lower SI values (dominant model, Δ= -1.0, p=0.04 as compared to the most prevalent haplotype. A non-significant decrease in SI was observed in in ADRB2 rs1042713 GG homozygotes, while subjects carrying SI-lowering genotypes at both SNPs (frequency = 8.4% showed much lower SI than non-carriers (Δ= -3.9, p<0.0001; p for interaction=0.025. The association was more evident in preschool girls, in whom SI showed a curvilinear trend across ages. In subgroup analyses, rs9999653 CC NMU or both GG ADRB2 genotypes were associated with either lower serum calcium or β-CrossLaps levels (p=0.01. This study in European children shows, for the first time in humans, a role for NMU gene through interaction with ADRB2 gene in bone strength regulation, more evident in preschool girls.

A study of the role of the FOXP2 and CNTNAP2 genes in persistent developmental stuttering.

Science.gov (United States)

Han, Tae-Un; Park, John; Domingues, Carlos F; Moretti-Ferreira, Danilo; Paris, Emily; Sainz, Eduardo; Gutierrez, Joanne; Drayna, Dennis

2014-09-01

A number of speech disorders including stuttering have been shown to have important genetic contributions, as indicated by high heritability estimates from twin and other studies. We studied the potential contribution to stuttering from variants in the FOXP2 gene, which have previously been associated with developmental verbal dyspraxia, and from variants in the CNTNAP2 gene, which have been associated with specific language impairment (SLI). DNA sequence analysis of these two genes in a group of 602 unrelated cases, all with familial persistent developmental stuttering, revealed no excess of potentially deleterious coding sequence variants in the cases compared to a matched group of 487 well characterized neurologically normal controls. This was compared to the distribution of variants in the GNPTAB, GNPTG, and NAGPA genes which have previously been associated with persistent stuttering. Using an expanded subject data set, we again found that NAGPA showed significantly different mutation frequencies in North Americans of European descent (p=0.0091) and a significant difference existed in the mutation frequency of GNPTAB in Brazilians (p=0.00050). No significant differences in mutation frequency in the FOXP2 and CNTNAP2 genes were observed between cases and controls. To examine the pattern of expression of these five genes in the human brain, real time quantitative reverse transcription PCR was performed on RNA purified from 27 different human brain regions. The expression patterns of FOXP2 and CNTNAP2 were generally different from those of GNPTAB, GNPTG and NAPGA in terms of relatively lower expression in the cerebellum. This study provides an improved estimate of the contribution of mutations in GNPTAB, GNPTG and NAGPA to persistent stuttering, and suggests that variants in FOXP2 and CNTNAP2 are not involved in the genesis of familial persistent stuttering. This, together with the different brain expression patterns of GNPTAB, GNPTG, and NAGPA compared to that of

The expression characteristics of mt-ND2 gene in chicken.

Science.gov (United States)

Zhang, Wenwen; Hou, Lingling; Wang, Ting; Lu, Weiwei; Tao, Yafei; Chen, Wen; Du, Xiaohui; Huang, Yanqun

2016-09-01

Subunit 2 of NADH dehydrogenase (ND2) is encoded by the mt-ND2 gene and plays a critical role in controlling the production of the mitochondrial reactive oxygen species. Our study focused on exploring the mt-ND2 tissue expression patterns and the effects of energy restriction and dietary fat (linseed oil, corn oil, sesame oil or lard) level (2.5% and 5%) on its expression in chicken. The results showed that mt-ND2 gene was expressed in the 15 tissues of hybrid chickens with the highest level in heart and lowest level in pancreas tissue; 30% energy restriction did not significantly affect mt-ND2 mRNA level in chicken liver tissue. Both the mt-ND2 mRNA levels in chicken pectoralis (p chicken age (p chicken age (p chicken age.

Genotyping of BRCA1, BRCA2, p53, CDKN2A, MLH1 and MSH2 genes in a male patient with secondary breast cancer

International Nuclear Information System (INIS)

Vodusek, Ana Lina; Novakovic, Srdjan; Stegel, Vida; Jereb, Berta

2011-01-01

Some tumour suppressor genes (BRCA2) and mismatch repair genes (MSH2, MLH1) are correlated with an increased risk for male breast cancer. Our patient developed secondary breast cancer after the treatment for Hodgkin’s disease in childhood. DNA was isolated from the patients’ blood and screened for mutations, polymorphisms and variants in BRCA1, BRCA2, p53, CDKN2A, MLH1 and MSH2 genes. We found no mutations but common polymorphisms, and three variants in mismatch repair genes. Nucleotide variants c.2006-6T>C and p.G322D in MSH2 might be correlated with male breast cancer