assessment code rac: Topics by Science.gov

Sample records for assessment code rac

Feasibility and Top Level Design of a Scalable Emergency Response System for Oceangoing Assets

DTIC Science & Technology

2008-10-20

hazard response. The DC is responsible for the initial response. In a small-scale hazard situation, the DC will assign a Risk Assessment Code (RAC) and...Qualification Standard R&D Research and Development RAC Risk Assessment Code RADSAFE Radiological Safety RAM Rolling Airframe Missile RFID Radio...easily be used for other environmental remediation efforts including Superfund sites, decommissioned Navy vessels and Brownfield locations, among others
On the RAC. CIOs must work to make their organization's time with CMS Recovery Audit Contractors as painless as possible.

PubMed

Lawrence, Daphne

2009-01-01

CIOs should act as a team with HIM and Finance to prepare for RAC audits. CIOs can take the lead in looking at improved coding systems, and can be involved in creating policies and procedures for the hospital's RAC team. RAC is an opportunity to improve documentation, coding and data analysis. RAC appeals will become more common as states share lessons learned. Follow the money and check on claims that are frequently returned.
Random access codes and nonlocal resources

NASA Astrophysics Data System (ADS)

Chaturvedi, Anubhav; Pawlowski, Marcin; Horodecki, Karol

2017-08-01

This work explores the notion of inter-convertibility between a cryptographic primitive: the random access code (RAC) and bipartite no-signaling nonlocal resources. To this end we introduce two generalizations of the Popescu-Rohrlich box (PR) and investigate their relation with the corresponding RACs. The first generalization is based on the number of Alice's input bits; we refer to it as the Bn-box. We show that the no-signaling condition imposes an equivalence between the Bn-box and the (n →1 ) RAC (encoding of n input bits to 1 bit of message). As an application we show that (n -1 ) PRs supplemented with one bit communication are necessary and sufficient to win a (n →1 ) RAC with certainty. Furthermore, we present a signaling instant of a perfectly working (n →1 ) RAC which cannot simulate the Bn-box, thus showing that it is weaker than its no-signaling counterpart. For the second generalization we replace Alice's input bits with d its (d -leveled classical systems); we call this the Bnd-box. In this case the no-signaling condition is not enough to enforce an equivalence between the Bnd-box and (n →1 ,d ) RAC (encoding of n input d its to 1 d it of message); i.e., while the Bnd-box can win a (n →1 ,d ) RAC with certainty, not all no-signaling instances of a (n →1 ,d ) RAC can simulate the Bnd-box. We use resource inequalities to quantitatively capture these results.
Distribution and risk assessment of heavy metals in sewage sludge after ozonation.

PubMed

Zhang, Jian; Tian, Yu; Zhang, Jun; Li, Ning; Kong, Lingchao; Yu, Ming; Zuo, Wei

2017-02-01

In this paper, transformation of chemical forms of heavy metals (Cu, Zn, Ni, Pb, Cr, Cd, Mn, and Mg) in sewage sludge (SS) during ozonation was investigated. Meanwhile, the risk of heavy metals to environment in ozonated sludge (OS) and SS was estimated according to risk assessment code (RAC). The residual rates of heavy metals were over 72.8 %, which demonstrated that the heavy metals in SS were mainly existed in the OS after ozonation. The results indicated that the ozonation had an effect on the redistribution of heavy metals. The comparisons of the RAC between OS and SS indicated that the environmental risk of heavy metals in OS was aggravated compared to SS, except for Mg. Consequently, it was suggested that the OS should be pretreated before application.
Mechanisms of splicing-dependent trans-synaptic adhesion by PTPδ-IL1RAPL1/IL-1RAcP for synaptic differentiation

NASA Astrophysics Data System (ADS)

Yamagata, Atsushi; Yoshida, Tomoyuki; Sato, Yusuke; Goto-Ito, Sakurako; Uemura, Takeshi; Maeda, Asami; Shiroshima, Tomoko; Iwasawa-Okamoto, Shiho; Mori, Hisashi; Mishina, Masayoshi; Fukai, Shuya

2015-04-01

Synapse formation is triggered through trans-synaptic interaction between pairs of pre- and postsynaptic adhesion molecules, the specificity of which depends on splice inserts known as `splice-insert signaling codes'. Receptor protein tyrosine phosphatase δ (PTPδ) can bidirectionally induce pre- and postsynaptic differentiation of neurons by trans-synaptically binding to interleukin-1 receptor accessory protein (IL-1RAcP) and IL-1RAcP-like-1 (IL1RAPL1) in a splicing-dependent manner. Here, we report crystal structures of PTPδ in complex with IL1RAPL1 and IL-1RAcP. The first immunoglobulin-like (Ig) domain of IL1RAPL1 directly recognizes the first splice insert, which is critical for binding to IL1RAPL1. The second splice insert functions as an adjustable linker that positions the Ig2 and Ig3 domains of PTPδ for simultaneously interacting with the Ig1 domain of IL1RAPL1 or IL-1RAcP. We further identified the IL1RAPL1-specific interaction, which appears coupled to the first-splice-insert-mediated interaction. Our results thus reveal the decoding mechanism of splice-insert signaling codes for synaptic differentiation induced by trans-synaptic adhesion between PTPδ and IL1RAPL1/IL-1RAcP.
Predicting the Mobility and Burial of Underwater Unexploded Ordnance (UXO) Using the UXO Mobility Model (ESTCP) 200417

DTIC Science & Technology

2009-11-01

Abbreviations and Acronyms Acronym Definition ADCP Acoustic Doppler Current Profiler AGD Applications Guidance Document ARAMS Army Risk Assessment Modeling...Center iv NESDI Navy Environmental Sustainability Development to Integration NOS National Ocean Service NS Naval Station NWS Naval Weapons...Plan QAS Quality Assurance Specialist RAC Risk Assessment Code REF/DIF Refraction/Diffraction ROI Return on Investment SAJ Dr. Scott A. Jenkins
How to staff for RACs.

PubMed

Brocato, Lori; Hirschl, Nancy; Padfield, Stanley

2010-01-01

To meet the challenges presented by recovery audit contractors (RACs), hospitals should perform six tasks that require appropriate investments in staff: conduct a financial risk assessment of the impact of RAC reviews on the organization; establish a RAC team and assign a coordinator; receive and fill RAC requests; track RAC activity; manage RAC appeals; analyze RAC audit outcomes.
Complementarity between entanglement-assisted and quantum distributed random access code

NASA Astrophysics Data System (ADS)

Hameedi, Alley; Saha, Debashis; Mironowicz, Piotr; Pawłowski, Marcin; Bourennane, Mohamed

2017-05-01

Collaborative communication tasks such as random access codes (RACs) employing quantum resources have manifested great potential in enhancing information processing capabilities beyond the classical limitations. The two quantum variants of RACs, namely, quantum random access code (QRAC) and the entanglement-assisted random access code (EARAC), have demonstrated equal prowess for a number of tasks. However, there do exist specific cases where one outperforms the other. In this article, we study a family of 3 →1 distributed RACs [J. Bowles, N. Brunner, and M. Pawłowski, Phys. Rev. A 92, 022351 (2015), 10.1103/PhysRevA.92.022351] and present its general construction of both the QRAC and the EARAC. We demonstrate that, depending on the function of inputs that is sought, if QRAC achieves the maximal success probability then EARAC fails to do so and vice versa. Moreover, a tripartite Bell-type inequality associated with the EARAC variants reveals the genuine multipartite nonlocality exhibited by our protocol. We conclude with an experimental realization of the 3 →1 distributed QRAC that achieves higher success probabilities than the maximum possible with EARACs for a number of tasks.
Operating Profitability of For-Profit and Not-for-Profit Florida Community Hospitals During Medicare Policy Changes, 2000 to 2010.

PubMed

Langland-Orban, Barbara; Large, John T; Sear, Alan M; Zhang, Hanze; Zhang, Nanhua

2015-01-01

Medicare Advantage was implemented in 2004 and the Recovery Audit Contractor (RAC) program was implemented in Florida during 2005. Both increase surveillance of medical necessity and deny payments for improper admissions. The purpose of the present study was to determine their potential impact on for-profit (FP) and not-for-profit (NFP) hospital operating margins in Florida. FP hospitals were expected to be more adversely affected as admissions growth has been one strategy to improve stock performance, which is not a consideration at NFPs. This study analyzed Florida community hospitals from 2000 through 2010, assessing changes in pre-tax operating margin (PTOM). Florida Agency for Health Care Administration data were analyzed for 104 community hospitals (62 FPs and 42 NFPs). Academic, public, and small hospitals were excluded. A mixed-effects model was used to assess the association of RAC implementation, organizational and payer type variables, and ownership interaction effects on PTOM. FP hospitals began the period with a higher average PTOM, but converged with NFPs during the study period. The average Medicare Advantage effect was not significant for either ownership type. The magnitude of the RAC variable was significantly negative for average PTOM at FPs (-4.68) and positive at NFPs (0.08), meaning RAC was associated with decreasing PTOM at FP hospitals only. RAC complements other Medicare surveillance systems that detect medically unnecessary admissions, coding errors, fraud, and abuse. Since its implementation in Florida, average FP and NFP operating margins have been similar, such that the higher margins reported for FP hospitals in the 1990s are no longer evident. © The Author(s) 2015.
Operating Profitability of For-Profit and Not-for-Profit Florida Community Hospitals During Medicare Policy Changes, 2000 to 2010

PubMed Central

Langland-Orban, Barbara; Large, John T.; Sear, Alan M.; Zhang, Hanze; Zhang, Nanhua

2015-01-01

Medicare Advantage was implemented in 2004 and the Recovery Audit Contractor (RAC) program was implemented in Florida during 2005. Both increase surveillance of medical necessity and deny payments for improper admissions. The purpose of the present study was to determine their potential impact on for-profit (FP) and not-for-profit (NFP) hospital operating margins in Florida. FP hospitals were expected to be more adversely affected as admissions growth has been one strategy to improve stock performance, which is not a consideration at NFPs. This study analyzed Florida community hospitals from 2000 through 2010, assessing changes in pre-tax operating margin (PTOM). Florida Agency for Health Care Administration data were analyzed for 104 community hospitals (62 FPs and 42 NFPs). Academic, public, and small hospitals were excluded. A mixed-effects model was used to assess the association of RAC implementation, organizational and payer type variables, and ownership interaction effects on PTOM. FP hospitals began the period with a higher average PTOM, but converged with NFPs during the study period. The average Medicare Advantage effect was not significant for either ownership type. The magnitude of the RAC variable was significantly negative for average PTOM at FPs (−4.68) and positive at NFPs (0.08), meaning RAC was associated with decreasing PTOM at FP hospitals only. RAC complements other Medicare surveillance systems that detect medically unnecessary admissions, coding errors, fraud, and abuse. Since its implementation in Florida, average FP and NFP operating margins have been similar, such that the higher margins reported for FP hospitals in the 1990s are no longer evident. PMID:26294267
Repression of YdaS Toxin Is Mediated by Transcriptional Repressor RacR in the Cryptic rac Prophage of Escherichia coli K-12.

PubMed

Krishnamurthi, Revathy; Ghosh, Swagatha; Khedkar, Supriya; Seshasayee, Aswin Sai Narain

2017-01-01

Horizontal gene transfer is a major driving force behind the genomic diversity seen in prokaryotes. The cryptic rac prophage in Escherichia coli K-12 carries the gene for a putative transcription factor RacR, whose deletion is lethal. We have shown that the essentiality of racR in E. coli K-12 is attributed to its role in transcriptionally repressing toxin gene(s) called ydaS and ydaT , which are adjacent to and coded divergently to racR . IMPORTANCE Transcription factors in the bacterium E. coli are rarely essential, and when they are essential, they are largely toxin-antitoxin systems. While studying transcription factors encoded in horizontally acquired regions in E. coli , we realized that the protein RacR, a putative transcription factor encoded by a gene on the rac prophage, is an essential protein. Here, using genetics, biochemistry, and bioinformatics, we show that its essentiality derives from its role as a transcriptional repressor of the ydaS and ydaT genes, whose products are toxic to the cell. Unlike type II toxin-antitoxin systems in which transcriptional regulation involves complexes of the toxin and antitoxin, repression by RacR is sufficient to keep ydaS transcriptionally silent.
Carboxyl-terminal isoprenylation of ras-related GTP-binding proteins encoded by rac1, rac2, and ralA.

PubMed

Kinsella, B T; Erdman, R A; Maltese, W A

1991-05-25

Membrane localization of p21ras is dependent upon its posttranslational modification by a 15-carbon farnesyl group. The isoprenoid is linked to a cysteine located within a conserved carboxyl-terminal sequence termed the "CAAX" box (where C is cysteine, A is an aliphatic amino acid, and X is any amino acid). We now show that three GTP-binding proteins encoded by the recently identified rac1, rac2, and ralA genes also undergo isoprenoid modification. cDNAs coding for each protein were transcribed in vitro, and the RNAs were translated in reticulocyte lysates. Incorporation of isoprenoid precursors, [3H]mevalonate or [3H]farnesyl pyrophosphate, indicated that the translation products were modified by isoprenyl groups. A protein recognized by an antibody to rac1 also comigrated with a protein metabolically labeled by a product of [3H] mevalonate in cultured cells. Gel permeation chromatography of radiolabeled hydrocarbons released from the rac1, rac2, and ralA proteins by reaction with Raney nickel catalyst indicated that unlike p21Hras, which was modified by a 15-carbon moiety, the rac and ralA translation products were modified by 20-carbon isoprenyl groups. Site-directed mutagenesis established that the isoprenylated cysteines in the rac1, rac2, and ralA proteins were located in the fourth position from the carboxyl terminus. The three-amino acid extension distal to the cysteine was required for this modification. The isoprenylation of rac1 (CSLL), ralA (CCIL), and the site-directed mutants rac1 (CRLL) and ralA (CSIL), demonstrates that the amino acid adjacent to the cysteine need not be aliphatic. Therefore, proteins with carboxyl-terminal CXXX sequences that depart from the CAAX motif should be considered as potential targets for isoprenoid modification.
Identification of Potential Hazard using Hazard Identification and Risk Assessment

NASA Astrophysics Data System (ADS)

Sari, R. M.; Syahputri, K.; Rizkya, I.; Siregar, I.

2017-03-01

This research was conducted in the paper production’s company. These Paper products will be used as a cigarette paper. Along in the production’s process, Company provides the machines and equipment that operated by workers. During the operations, all workers may potentially injured. It known as a potential hazard. Hazard identification and risk assessment is one part of a safety and health program in the stage of risk management. This is very important as part of efforts to prevent occupational injuries and diseases resulting from work. This research is experiencing a problem that is not the identification of potential hazards and risks that would be faced by workers during the running production process. The purpose of this study was to identify the potential hazards by using hazard identification and risk assessment methods. Risk assessment is done using severity criteria and the probability of an accident. According to the research there are 23 potential hazard that occurs with varying severity and probability. Then made the determination Risk Assessment Code (RAC) for each potential hazard, and gained 3 extreme risks, 10 high risks, 6 medium risks and 3 low risks. We have successfully identified potential hazard using RAC.
Spatial-temporal distribution and risk assessment of mercury in different fractions in surface sediments from the Yangtze River estuary.

PubMed

Wang, Qingrui; Liu, Ruimin; Men, Cong; Xu, Fei; Guo, Lijia; Shen, Zhenyao

2017-11-15

The temporal and spatial distributions of mercury in different fractions and its potential ecological risk were investigated in sediments from the Yangtze River estuary (YRE) by analyzing data collected from the study area. The results showed that mercury in the organic and residual fractions had dominant proportions, from 15.2% to 48.52% and from 45.96% to 81.59%, respectively. The fractions were more susceptible to seasonal changes than other fractions. Higher proportions of mercury in organic fraction were found in wet seasons; the opposite was true for mercury in residual fraction. With respect to the spatial distribution, the concentration mercury in exchangeable, carbonate and Fe-Mn oxide fractions showed a decreasing trend from the inner estuary to the outer estuary, but no obvious trends were found in the distributions of mercury in the organic and residual fractions. The risk assessment code (RAC) was used to evaluate the potential ecological risk in the study area based on the proportions of exchangeable and carbonate fractions. The average RAC values during the four periods were 6.00%, 2.20%, 2.83%, and 0.61%. Although these values show that the risk in the study area is generally low, the distribution of RAC values indicates that the inner estuary has a medium risk, with a value up to 10%. Copyright © 2017 Elsevier Ltd. All rights reserved.
The Validation of Macro and Micro Observations of Parent-Child Dynamics Using the Relationship Affect Coding System in Early Childhood.

PubMed

Dishion, Thomas J; Mun, Chung Jung; Tein, Jenn-Yun; Kim, Hanjoe; Shaw, Daniel S; Gardner, Frances; Wilson, Melvin N; Peterson, Jenene

2017-04-01

This study examined the validity of micro social observations and macro ratings of parent-child interaction in early to middle childhood. Seven hundred and thirty-one families representing multiple ethnic groups were recruited and screened as at risk in the context of Women, Infant, and Children (WIC) Nutritional Supplement service settings. Families were randomly assigned to the Family Checkup (FCU) intervention or the control condition at age 2 and videotaped in structured interactions in the home at ages 2, 3, 4, and 5. Parent-child interaction videotapes were micro-coded using the Relationship Affect Coding System (RACS) that captures the duration of two mutual dyadic states: positive engagement and coercion. Macro ratings of parenting skills were collected after coding the videotapes to assess parent use of positive behavior support and limit setting skills (or lack thereof). Confirmatory factor analyses revealed that the measurement model of macro ratings of limit setting and positive behavior support was not supported by the data, and thus, were excluded from further analyses. However, there was moderate stability in the families' micro social dynamics across early childhood and it showed significant improvements as a function of random assignment to the FCU. Moreover, parent-child dynamics were predictive of chronic behavior problems as rated by parents in middle childhood, but not emotional problems. We conclude with a discussion of the validity of the RACS and on methodological advantages of micro social coding over the statistical limitations of macro rating observations. Future directions are discussed for observation research in prevention science.
Acute tier-1 and tier-2 effect assessment approaches in the EFSA Aquatic Guidance Document: are they sufficiently protective for insecticides?

PubMed

van Wijngaarden, René P A; Maltby, Lorraine; Brock, Theo C M

2015-08-01

The objective of this paper is to evaluate whether the acute tier-1 and tier-2 methods as proposed by the Aquatic Guidance Document recently published by the European Food Safety Authority (EFSA) are appropriate for deriving regulatory acceptable concentrations (RACs) for insecticides. The tier-1 and tier-2 RACs were compared with RACs based on threshold concentrations from micro/mesocosm studies (ETO-RAC). A lower-tier RAC was considered as sufficiently protective, if less than the corresponding ETO-RAC. ETO-RACs were calculated for repeated (n = 13) and/or single pulsed applications (n = 17) of 26 insecticides to micro/mesocosms, giving a maximum of 30 insecticide × application combinations (i.e. cases) for comparison. Acute tier-1 RACs (for 24 insecticides) were lower than the corresponding ETO-RACs in 27 out of 29 cases, while tier-2 Geom-RACs (for 23 insecticides) were lower in 24 out of 26 cases. The tier-2 SSD-RAC (for 21 insecticides) using HC5 /3 was lower than the ETO-RAC in 23 out of 27 cases, whereas the tier-2 SSD-RAC using HC5 /6 was protective in 25 out of 27 cases. The tier-1 and tier-2 approaches proposed by EFSA for acute effect assessment are sufficiently protective for the majority of insecticides evaluated. Further evaluation may be needed for insecticides with more novel chemistries (neonicotinoids, biopesticides) and compounds that show delayed effects (insect growth regulators). © 2014 Society of Chemical Industry.
Health effects of risk-assessment categories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kramer, C.F.; Rybicka, K.; Knutson, A.

Environmental and occupational health effects associated with exposures to various chemicals are a subject of increasing concern. One recently developed methodology for assessing the health impacts of various chemical compounds involves the classification of similar chemicals into risk-assessment categories (RACs). This report reviews documented human health effects for a broad range of pollutants, classified by RACs. It complements other studies that have estimated human health effects by RAC based on analysis and extrapolation of data from animal research.
Improved classical and quantum random access codes

NASA Astrophysics Data System (ADS)

Liabøtrø, O.

2017-05-01

A (quantum) random access code ((Q)RAC) is a scheme that encodes n bits into m (qu)bits such that any of the n bits can be recovered with a worst case probability p >1/2 . We generalize (Q)RACs to a scheme encoding n d -levels into m (quantum) d -levels such that any d -level can be recovered with the probability for every wrong outcome value being less than 1/d . We construct explicit solutions for all n ≤d/2m-1 d -1 . For d =2 , the constructions coincide with those previously known. We show that the (Q)RACs are d -parity oblivious, generalizing ordinary parity obliviousness. We further investigate optimization of the success probabilities. For d =2 , we use the measure operators of the previously best-known solutions, but improve the encoding states to give a higher success probability. We conjecture that for maximal (n =4m-1 ,m ,p ) QRACs, p =1/2 {1 +[(√{3}+1)m-1 ] -1} is possible, and show that it is an upper bound for the measure operators that we use. We then compare (n ,m ,pq) QRACs with classical (n ,2 m ,pc) RACs. We can always find pq≥pc , but the classical code gives information about every input bit simultaneously, while the QRAC only gives information about a subset. For several different (n ,2 ,p ) QRACs, we see the same trade-off, as the best p values are obtained when the number of bits that can be obtained simultaneously is as small as possible. The trade-off is connected to parity obliviousness, since high certainty information about several bits can be used to calculate probabilities for parities of subsets.
Risk assessment of heavy metals from combustion of pelletized municipal sewage sludge.

PubMed

Xiao, Zhihua; Yuan, Xingzhong; Leng, Lijian; Jiang, Longbo; Chen, Xiaohong; Zhibin, Wu; Xin, Peng; Jiachao, Zhang; Zeng, Guangming

2016-02-01

Fly ash and slag are important by-products obtained from combustion of municipal sewage sludge (MSS) after pelletization. The quantitative environmental impact assessment of heavy metals in fly ash and slag, compared to MSS, were performed in accordance with bioavailability and eco-toxicity, geo-accumulation index (GAI), risk assessment code (RAC), and potential ecological risk index (PERI). The results demonstrated that not only direct but also long-term bioavailability and eco-toxicity of heavy metals in fly ash and slag decreased except direct bioavailability and eco-toxicity of Pb in fly ash. The GAI demonstrated that combustion significantly weakened (P < 0.05) the pollution levels of heavy metals. PERI indicated that all risks attributed to heavy metals were significantly lowered (P < 0.05) from 777.07 (very high risk) in MSS to 288.72 (moderate risk) and 64.55 (low risk) in fly ash and slag, respectively. In terms of the RAC, seven heavy metals had low even no risk to the environments after combustion besides As in slag. The environmental risk of heavy metals in fly ash and slag was decreased compared with MSS. However, the results of PERI showed that fly ash had a moderate risk.
The Validation of Macro and Micro Observations of Parent–Child Dynamics Using the Relationship Affect Coding System in Early Childhood

PubMed Central

Mun, Chung Jung; Tein, Jenn-Yun; Kim, Hanjoe; Shaw, Daniel S.; Gardner, Frances; Wilson, Melvin N.; Peterson, Jenene

2018-01-01

This study examined the validity of micro social observations and macro ratings of parent–child interaction in early to middle childhood. Seven hundred and thirty-one families representing multiple ethnic groups were recruited and screened as at risk in the context of Women, Infant, and Children (WIC) Nutritional Supplement service settings. Families were randomly assigned to the Family Checkup (FCU) intervention or the control condition at age 2 and videotaped in structured interactions in the home at ages 2, 3, 4, and 5. Parent–child interaction videotapes were microcoded using the Relationship Affect Coding System (RACS) that captures the duration of two mutual dyadic states: positive engagement and coercion. Macro ratings of parenting skills were collected after coding the videotapes to assess parent use of positive behavior support and limit setting skills (or lack thereof). Confirmatory factor analyses revealed that the measurement model of macro ratings of limit setting and positive behavior support was not supported by the data, and thus, were excluded from further analyses. However, there was moderate stability in the families’ micro social dynamics across early childhood and it showed significant improvements as a function of random assignment to the FCU. Moreover, parent–child dynamics were predictive of chronic behavior problems as rated by parents in middle childhood, but not emotional problems. We conclude with a discussion of the validity of the RACS and on methodological advantages of micro social coding over the statistical limitations of macro rating observations. Future directions are discussed for observation research in prevention science. PMID:27620623

Speciation and environmental risk assessment of heavy metal in bio-oil from liquefaction/pyrolysis of sewage sludge.

PubMed

Yuan, Xingzhong; Leng, Lijian; Huang, Huajun; Chen, Xiaohong; Wang, Hou; Xiao, Zhihua; Zhai, Yunbo; Chen, Hongmei; Zeng, Guangming

2015-02-01

Liquefaction bio-oil (LBO) produced with ethanol (or acetone) as the solvent and pyrolysis bio-oil (PBO) produced at 550°C (or 850°C) from sewage sludge (SS) were produced, and were characterized and evaluated in terms of their heavy metal (HM) composition. The total concentration, speciation and leaching characteristic of HMs (Cu, Cr, Pb, Zn, Cd, and Ni) in both LBO and PBO were investigated. The total concentration and exchangeable fraction of Zn and Ni in bio-oils were at surprisingly high levels. Quantitative risk assessment of HM in bio-oils was performed by the method of risk assessment code (RAC), potential ecological risk index (PERI) and geo-accumulation index (GAI). Ni in bio-oil produced by pyrolysis at 850°C (PBO850) and Zn in bio-oil by liquefaction at 360°C with ethanol as solvent (LBO-360E) were evaluated to possess very high risk to the environment according to RAC. Additionally, Cd in PBO850 and LBO-360E were evaluated by PERI to have very high risk and high risk, respectively, while Cd in all bio-oils was assessed moderately contaminated according to GAI. Copyright © 2014 Elsevier Ltd. All rights reserved.
Two distinct mTORC2-dependent pathways converge on Rac1 to drive breast cancer metastasis.

PubMed

Morrison Joly, Meghan; Williams, Michelle M; Hicks, Donna J; Jones, Bayley; Sanchez, Violeta; Young, Christian D; Sarbassov, Dos D; Muller, William J; Brantley-Sieders, Dana; Cook, Rebecca S

2017-06-30

The importance of the mTOR complex 2 (mTORC2) signaling complex in tumor progression is becoming increasingly recognized. HER2-amplified breast cancers use Rictor/mTORC2 signaling to drive tumor formation, tumor cell survival and resistance to human epidermal growth factor receptor 2 (HER2)-targeted therapy. Cell motility, a key step in the metastatic process, can be activated by mTORC2 in luminal and triple negative breast cancer cell lines, but its role in promoting metastases from HER2-amplified breast cancers is not yet clear. Because Rictor is an obligate cofactor of mTORC2, we genetically engineered Rictor ablation or overexpression in mouse and human HER2-amplified breast cancer models for modulation of mTORC2 activity. Signaling through mTORC2-dependent pathways was also manipulated using pharmacological inhibitors of mTOR, Akt, and Rac. Signaling was assessed by western analysis and biochemical pull-down assays specific for Rac-GTP and for active Rac guanine nucleotide exchange factors (GEFs). Metastases were assessed from spontaneous tumors and from intravenously delivered tumor cells. Motility and invasion of cells was assessed using Matrigel-coated transwell assays. We found that Rictor ablation potently impaired, while Rictor overexpression increased, metastasis in spontaneous and intravenously seeded models of HER2-overexpressing breast cancers. Additionally, migration and invasion of HER2-amplified human breast cancer cells was diminished in the absence of Rictor, or upon pharmacological mTOR kinase inhibition. Active Rac1 was required for Rictor-dependent invasion and motility, which rescued invasion/motility in Rictor depleted cells. Rictor/mTORC2-dependent dampening of the endogenous Rac1 inhibitor RhoGDI2, a factor that correlated directly with increased overall survival in HER2-amplified breast cancer patients, promoted Rac1 activity and tumor cell invasion/migration. The mTORC2 substrate Akt did not affect RhoGDI2 dampening, but partially increased Rac1 activity through the Rac-GEF Tiam1, thus partially rescuing cell invasion/motility. The mTORC2 effector protein kinase C (PKC)α did rescue Rictor-mediated RhoGDI2 downregulation, partially rescuing Rac-guanosine triphosphate (GTP) and migration/motility. These findings suggest that mTORC2 uses two coordinated pathways to activate cell invasion/motility, both of which converge on Rac1. Akt signaling activates Rac1 through the Rac-GEF Tiam1, while PKC signaling dampens expression of the endogenous Rac1 inhibitor, RhoGDI2.
Inhibition of prostate smooth muscle contraction and prostate stromal cell growth by the inhibitors of Rac, NSC23766 and EHT1864.

PubMed

Wang, Y; Kunit, T; Ciotkowska, A; Rutz, B; Schreiber, A; Strittmatter, F; Waidelich, R; Liu, C; Stief, C G; Gratzke, C; Hennenberg, M

2015-06-01

Medical therapy of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) targets smooth muscle contraction in the prostate, or prostate growth. However, current therapeutic options are insufficient. Here, we investigated the role of Rac in the control of smooth muscle tone in human prostates and growth of prostate stromal cells. Experiments were performed using human prostate tissues from radical prostatectomy and cultured stromal cells (WPMY-1). Expression of Rac was examined by Western blot and fluorescence staining. Effects of Rac inhibitors (NSC23766 and EHT1864) on contractility were assessed in the organ bath. The effects of Rac inhibitors were assessed by pull-down, cytotoxicity using a cell counting kit, cytoskeletal organization by phalloidin staining and cell growth using an 5-ethynyl-2'-deoxyuridine assay. Expression of Rac1-3 was observed in prostate samples from each patient. Immunoreactivity for Rac1-3 was observed in the stroma, where it colocalized with the smooth muscle marker, calponin. NSC23766 and EHT1864 significantly reduced contractions of prostate strips induced by noradrenaline, phenylephrine or electrical field stimulation. NSC23766 and EHT1864 inhibited Rac activity in WPMY-1 cells. Survival of WPMY-1 cells ranged between 64 and 81% after incubation with NSC23766 (50 or 100 μM) or EHT1864 (25 μM) for 24 h. NSC23766 and EHT1864 induced cytoskeletal disorganization in WPMY-1 cells. Both inhibitors impaired the growth of WPMY-1 cells. Rac may be a link connecting the control of prostate smooth muscle tone with proliferation of smooth muscle cells. Improvements in LUTS suggestive of BPH by Rac inhibitors appears possible. © 2015 The British Pharmacological Society.
Cyclic Behavior of Low Rise Concrete Shear Walls Containing Recycled Coarse and Fine Aggregates.

PubMed

Qiao, Qiyun; Cao, Wanlin; Qian, Zhiwei; Li, Xiangyu; Zhang, Wenwen; Liu, Wenchao

2017-12-07

In this study, the cyclic behaviors of low rise concrete shear walls using recycled coarse or fine aggregates were investigated. Eight low rise Recycled Aggregates Concrete (RAC) shear wall specimens were designed and tested under a cyclic loading. The following parameters were varied: replacement percentages of recycled coarse or fine aggregates, reinforcement ratio, axial force ratio and X-shaped rebars brace. The failure characteristics, hysteretic behavior, strength and deformation capacity, strain characteristics and stiffness were studied. Test results showed that the using of the Recycled Coarse Aggregates (RCA) and its replacement ratio had almost no influence on the mechanical behavior of the shear wall; however, the using of Recycled Fine Aggregates (RFA) had a certain influence on the ductility of the shear wall. When the reinforcement ratio increased, the strength and ductility also increased. By increasing the axial force ratio, the strength increased but the ductility decreased significantly. The encased brace had a significant effect on enhancing the RAC shear walls. The experimental maximum strengths were evaluated with existing design codes, it was indicated that the strength evaluation of the low rise RAC shear walls can follow the existing design codes of the conventional concrete shear walls.
Identifying factors that predict the choice and success rate of radial artery catheterisation in contemporary real world cardiology practice: a sub-analysis of the PREVAIL study data.

PubMed

Pristipino, Christian; Roncella, Adriana; Trani, Carlo; Nazzaro, Marco S; Berni, Andrea; Di Sciascio, Germano; Sciahbasi, Alessandro; Musarò, Salvatore Donato; Mazzarotto, Pietro; Gioffrè, Gaetano; Speciale, Giulio

2010-06-01

To assess: the reasons behind an operator choosing to perform radial artery catheterisation (RAC) as against femoral arterial catheterisation, and to explore why RAC may fail in the real world. A pre-determined analysis of PREVAIL study database was performed. Relevant data were collected in a prospective, observational survey of 1,052 consecutive patients undergoing invasive cardiovascular procedures at nine Italian hospitals over a one month observation period. By multivariate analysis, the independent predictors of RAC choice were having the procedure performed: (1) at a high procedural volume centre; and (2) by an operator who performs a high volume of radial procedures; clinical variables played no statistically significant role. RAC failure was predicted independently by (1) a lower operator propensity to use RAC; and (2) the presence of obstructive peripheral artery disease. A 10-fold lower rate of RAC failure was observed among operators who perform RAC for > 85% of their personal caseload than among those who use RAC < 25% of the time (3.8% vs. 33.0%, respectively); by receiver operator characteristic (ROC) analysis, no threshold value for operator RAC volume predicted RAC failure. A routine RAC in all-comers is superior to a selective strategy in terms of feasibility and success rate.
Subcritical water treatment of explosive and heavy metals co-contaminated soil: Removal of the explosive, and immobilization and risk assessment of heavy metals.

PubMed

Islam, Mohammad Nazrul; Jung, Ho-Young; Park, Jeong-Hun

2015-11-01

Co-contamination of explosives and heavy metals (HMs) in soil, particularly army shooting range soil, has received increasing environmental concern due to toxicity and risks to ecological systems. In this study, a subcritical water (SCW) extraction process was used to remediate the explosives-plus-HMs-co-contaminated soil. A quantitative evaluation of explosives in the treated soil, compared with untreated soil, was applied to assess explosive removal. The immobilization of HMs was assessed by toxicity characteristic leaching procedure tests, and by investigating the migration of HMs fractions. The environmental risk of HMs in the soil residue was assessed according to the risk assessment code (RAC) and ecological risk indices (Er and RI). The results indicated that SCW treatment could eliminate the explosives, >99%, during the remediation, while the HM was effectively immobilized. The effect of water temperature on reducing the explosives and the risk of HMs in soil was observed. A marked increase in the non-bioavailable concentration of each HM was observed, and the leaching rate of HMs was decreased by 70-97% after SCW treatment at 250 °C, showing the effective immobilization of HMs. According to the RAC or RI, each tested HM showed no or low risk to the environment after treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.
Risk Assessment of Potentially Toxic Elements (PTEs) Pollution at a Rural Industrial Wasteland in an Abandoned Metallurgy Factory in North China

PubMed Central

Chen, Jiajun

2018-01-01

The potential toxic elements (PTEs) pollution problems in many rural industrial wastelands have been observed to be conspicuous. Therefore, 40 top soil samples were collected from the wasteland of a typical rural metallurgy factory in Baoding, China. The total concentrations of six key PTEs were measured. The soil properties and speciation of the PTEs were also identified. Extremely high concentrations of As, Cd, Pb, and Zn were observed in the surface soils. Using the PTEs concentration in the top soils of the rural industrial wasteland, the following indices of pollution were calculated: the pollution load index (PLI), the geo-accumulation Index (Igeo), the risk assessment code (RAC), and the health risk assessment (HRA). The analysis of the PLI and Igeo indicated that site #1 was relatively clean, while sites #2 and #3 were heavily polluted. The results of the RAC showed that PTEs in top soils at sites #2 and #3 were significantly increased (p < 0.05) for Cd and Zn. The HRA indicated that both As and Pb presented non-carcinogenic risks to children and adults at sites #2 and #3. Our findings can be a reference for risk prevention of industrially abandoned land in rural China. PMID:29316642
Risk Assessment of Potentially Toxic Elements (PTEs) Pollution at a Rural Industrial Wasteland in an Abandoned Metallurgy Factory in North China.

PubMed

Sun, Zheng; Chen, Jiajun

2018-01-06

The potential toxic elements (PTEs) pollution problems in many rural industrial wastelands have been observed to be conspicuous. Therefore, 40 top soil samples were collected from the wasteland of a typical rural metallurgy factory in Baoding, China. The total concentrations of six key PTEs were measured. The soil properties and speciation of the PTEs were also identified. Extremely high concentrations of As, Cd, Pb, and Zn were observed in the surface soils. Using the PTEs concentration in the top soils of the rural industrial wasteland, the following indices of pollution were calculated: the pollution load index (PLI), the geo-accumulation Index (I geo ), the risk assessment code (RAC), and the health risk assessment (HRA). The analysis of the PLI and I geo indicated that site #1 was relatively clean, while sites #2 and #3 were heavily polluted. The results of the RAC showed that PTEs in top soils at sites #2 and #3 were significantly increased ( p < 0.05) for Cd and Zn. The HRA indicated that both As and Pb presented non-carcinogenic risks to children and adults at sites #2 and #3. Our findings can be a reference for risk prevention of industrially abandoned land in rural China.
Pak and Rac GTPases promote oncogenic KIT–induced neoplasms

PubMed Central

Martin, Holly; Mali, Raghuveer Singh; Ma, Peilin; Chatterjee, Anindya; Ramdas, Baskar; Sims, Emily; Munugalavadla, Veerendra; Ghosh, Joydeep; Mattingly, Ray R.; Visconte, Valeria; Tiu, Ramon V.; Vlaar, Cornelis P.; Dharmawardhane, Suranganie; Kapur, Reuben

2013-01-01

An acquired somatic mutation at codon 816 in the KIT receptor tyrosine kinase is associated with poor prognosis in patients with systemic mastocytosis and acute myeloid leukemia (AML). Treatment of leukemic cells bearing this mutation with an allosteric inhibitor of p21–activated kinase (Pak) or its genetic inactivation results in growth repression due to enhanced apoptosis. Inhibition of the upstream effector Rac abrogates the oncogene-induced growth and activity of Pak. Although both Rac1 and Rac2 are constitutively activated via the guanine nucleotide exchange factor (GEF) Vav1, loss of Rac1 or Rac2 alone moderately corrected the growth of KIT-bearing leukemic cells, whereas the combined loss resulted in 75% growth repression. In vivo, the inhibition of Vav or Rac or Pak delayed the onset of myeloproliferative neoplasms (MPNs) and corrected the associated pathology in mice. To assess the role of Rac GEFs in oncogene-induced transformation, we used an inhibitor of Rac, EHop-016, which specifically targets Vav1 and found that EHop-016 was a potent inhibitor of human and murine leukemic cell growth. These studies identify Pak and Rac GTPases, including Vav1, as potential therapeutic targets in MPN and AML involving an oncogenic form of KIT. PMID:24091327
Proteomic and Metabolomic Analyses Reveal Contrasting Anti-Inflammatory Effects of an Extract of Mucor Racemosus Secondary Metabolites Compared to Dexamethasone.

PubMed

Meier, Samuel M; Muqaku, Besnik; Ullmann, Ronald; Bileck, Andrea; Kreutz, Dominique; Mader, Johanna C; Knasmüller, Siegfried; Gerner, Christopher

2015-01-01

Classical drug assays are often confined to single molecules and targeting single pathways. However, it is also desirable to investigate the effects of complex mixtures on complex systems such as living cells including the natural multitude of signalling pathways. Evidence based on herbal medicine has motivated us to investigate potential beneficial health effects of Mucor racemosus (M rac) extracts. Secondary metabolites of M rac were collected using a good-manufacturing process (GMP) approved production line and a validated manufacturing process, in order to obtain a stable product termed SyCircue (National Drug Code USA: 10424-102). Toxicological studies confirmed that this product does not contain mycotoxins and is non-genotoxic. Potential effects on inflammatory processes were investigated by treating stimulated cells with M rac extracts and the effects were compared to the standard anti-inflammatory drug dexamethasone on the levels of the proteome and metabolome. Using 2D-PAGE, slight anti-inflammatory effects were observed in primary white blood mononuclear cells, which were more pronounced in primary human umbilical vein endothelial cells (HUVECs). Proteome profiling based on nLC-MS/MS analysis of tryptic digests revealed inhibitory effects of M rac extracts on pro-inflammatory cytoplasmic mediators and secreted cytokines and chemokines in these endothelial cells. This finding was confirmed using targeted proteomics, here treatment of stimulated cells with M rac extracts down-regulated the secretion of IL-6, IL-8, CXCL5 and GROA significantly. Finally, the modulating effects of M rac on HUVECs were also confirmed on the level of the metabolome. Several metabolites displayed significant concentration changes upon treatment of inflammatory activated HUVECs with the M rac extract, including spermine and lysophosphatidylcholine acyl C18:0 and sphingomyelin C26:1, while the bulk of measured metabolites remained unaffected. Interestingly, the effects of M rac treatment on lipids were orthogonal to the effect of dexamethasone underlining differences in the overall mode of action.
Use of a sparse sampling study design to assess transfer of tramadol and its O-desmethyl metabolite into transitional breast milk.

PubMed

Ilett, Kenneth F; Paech, Michael J; Page-Sharp, Madhu; Sy, Sherwin K; Kristensen, Judith H; Goy, Raymond; Chua, Sebastian; Christmas, Tracey; Scott, Karen L

2008-05-01

There are presently no published data on tramadol transfer into breast milk or on its effects in the breastfed infant. We have provided quantitative data on the absolute and relative infant doses of rac-tramadol and it rac-O-desmethyl metabolite for the breastfed infant. We have also demonstrated a novel sparse sampling data collection method for investigating infant exposure via milk. To investigate the transfer of rac-tramadol and its rac-O-desmethyl metabolite into transitional milk, and assess unwanted effects in the breastfed infant. Tramadol HCl (100 mg six hourly) was administered to 75 breastfeeding mothers for postoperative analgesia on days 2-4 after Caesarian section. Milk and plasma samples were collected after administration of four or more doses. Rac-tramadol and rac-O-desmethyltramadol were measured by high performance liquid chromatography. Milk : plasma ratio (M : P) and infant doses were calculated by standard methods. The behavioural characteristics of the exposed breastfed infants and a matched control group of infants not exposed to tramadol were also studied. RESULTS At steady-state, mean (95% CI) M : P was 2.2 (2.0, 2.4) for rac-tramadol and 2.8 (2.5, 3.1) for rac-O-desmethyltramadol. The estimated absolute and relative infant doses were 112 (102, 122) microg kg(-1) day(-1) and 30 (28, 32) microg kg(-1) day(-1), and 2.24% (2.04, 2.44)% and 0.64% (0.59, 0.69)% for rac-tramadol and rac-O-desmethyltramadol, respectively. The exposed infants and control breastfed infants had similar characteristics, including Apgar scores at birth and Neurologic and Adaptive Capacity Scores. The combined relative infant dose of 2.88% at steady-state was low. The similarity of NACS in exposed infants and controls suggests that there were no significant behavioural adverse effects. We conclude that short-term maternal use of tramadol during establishment of lactation is compatible with breastfeeding.
Pesticide authorization in the EU-environment unprotected?

PubMed

Stehle, Sebastian; Schulz, Ralf

2015-12-01

Pesticides constitute an integral part of high-intensity European agriculture. Prior to their authorization, a highly elaborated environmental risk assessment is mandatory according to EU pesticide legislation, i.e., Regulation (EC) No. 1107/2009. However, no field data-based evaluation of the risk assessment outcome, i.e., the regulatory acceptable concentrations (RACs), and therefore of the overall protectiveness of EU pesticide regulations exists. We conducted here a comprehensive meta-analysis using peer-reviewed literature on agricultural insecticide concentrations in EU surface waters and evaluated associated risks using the RACs derived from official European pesticide registration documents. As a result, 44.7 % of the 1566 cases of measured insecticide concentrations (MICs) in EU surface waters exceeded their respective RACs. It follows that current EU pesticide regulations do not protect the aquatic environment and that insecticides threaten aquatic biodiversity. RAC exceedances were significantly higher for insecticides authorized using conservative tier-I RACs and for more recently developed insecticide classes, i.e., pyrethroids. In addition, we identified higher risks, e.g., for smaller surface waters that are specifically considered in the regulatory risk assessment schemes. We illustrate the shortcomings of the EU regulatory risk assessment using two case studies that contextualize the respective risk assessment outcomes to field exposure. Overall, our meta-analysis challenges the field relevance and protectiveness of the regulatory environmental risk assessment conducted for pesticide authorization in the EU and indicates that critical revisions of related pesticide regulations and effective mitigation measures are urgently needed to substantially reduce the environmental risks arising from agricultural insecticide use.
Is the chronic Tier-1 effect assessment approach for insecticides protective for aquatic ecosystems?

PubMed

Brock, Theo Cm; Bhatta, Ranjana; van Wijngaarden, René Pa; Rico, Andreu

2016-10-01

We investigated the appropriateness of several methods, including those recommended in the Aquatic Guidance Document of the European Food Safety Authority (EFSA), for the derivation of chronic Tier-1 regulatory acceptable concentrations (RACs) for insecticides and aquatic organisms. The insecticides represented different chemical classes (organophosphates, pyrethroids, benzoylureas, insect growth regulators, biopesticides, carbamates, neonicotinoids, and miscellaneous). Chronic Tier-1 RACs derived using toxicity data for the standard species Daphnia magna, Chironomus spp., and/or Americamysis bahia, were compared with Tier-3 RACs derived from micro- and mesocosm studies on basis of the ecological threshold option (ETO-RACs). ETO-RACs could be derived for 31 insecticides applied to micro- and mesocosms in single or multiple applications, yielding a total number of 36 cases for comparison. The chronic Tier-1 RACs calculated according to the EFSA approach resulted in a sufficient protection level, except for 1 neonicotinoid (slightly underprotective) and for several pyrethroids if toxicity data for A. bahia were not included. This latter observation can be explained by 1) the fact that A. bahia is the most sensitive standard test species for pyrethroids, 2) the hydrophobic properties of pyrethroids, and 3) the fact that long-term effects observed in (epi) benthic arthropods may be better explained by exposure via the sediment than via overlying water. Besides including toxicity data for A. bahia, the protection level for pyrethroids can be improved by selecting both D. magna and Chironomus spp. as standard test species for chronic Tier-1 derivation. Although protective in the majority of cases, the conservativeness of the recommended chronic Tier-1 RACs appears to be less than an order of magnitude for a relatively large proportion of insecticides when compared with their Tier-3 ETO-RACs. This may leave limited options for refinement of the chronic effect assessment using laboratory toxicity data for additional species. Integr Environ Assess Manag 2016;12:747-758. © 2015 SETAC. © 2015 SETAC.
Long non-coding RNA linc-cdh4-2 inhibits the migration and invasion of HCC cells by targeting R-cadherin pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Yunzhen; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou 350025; Wang, Gaoxiong

Long non-coding RNAs (LncRNAs) have played very important roles in the malignancy behaviors of hepatocellular carcinoma (HCC). Linc-cdh4-2 (TCONS-00027978) is a novel LncRNA that has been identified in HCC tissues from our previous study. Overexpression of linc-cdh4-2 in HCC cell lines (SK-Hep-1 and Huh7) significantly decreases the migration and invasion abilities of these cells, while knockdown the expression of linc-cdh4-2 significantly increases the migration and invasion abilities. Interestingly, neither the over expression nor the knock down of linc-cdh4-2 could affect the viability and proliferation of HCC cells. Mechanistically, the linc-cdh4-2 could up-regulate the protein level of R-cadherin through direct bindingmore » that might improve the protein stability. Over expression of linc-cdh4-2 could significantly increase the protein levels of R-cadherin and decrease the protein levels of small GTPase RAC1, and vice-versa. Further knockdown R-cadherin in linc-cdh4-2 stably overexpressed cells, could significantly upregulate the protein levels of RAC1 and improve the cell migration and invasion abilities. Taken together, the novel linc-cdh4-2 may negatively regulate the motility of the HCC cells through targeting R-cadherin-RAC1 signaling pathway. - Highlights: • Linc-cdh4-2 negatively related with the invasion and metastasis ability of HCC cells. • Linc-cdh4-2 could up-regulate the protein level of R-cadherin through direct binding. • Knockdown of R-cadherin increases the migration and invasion abilities of HCC cell. • Knockdown of R-cadherin could significantly upregulate the protein levels of RAC1.« less
Pulmonary artery relative area change detects mild elevations in pulmonary vascular resistance and predicts adverse outcome in pulmonary hypertension.

PubMed

Swift, Andrew J; Rajaram, Smitha; Condliffe, Robin; Capener, Dave; Hurdman, Judith; Elliot, Charlie; Kiely, David G; Wild, Jim M

2012-10-01

The aim of this study was to evaluate the clinical use of magnetic resonance imaging measurements related to pulmonary artery stiffness in the evaluation of pulmonary hypertension (PH). A total of 134 patients with suspected PH underwent right heart catheterization (RHC) and magnetic resonance imaging on a 1.5-T scanner within 2 days. Phase contrast imaging at the pulmonary artery trunk and cine cardiac views were acquired. Pulmonary artery area change (AC), relative AC (RAC), compliance (AC/pulse pressure from RHC), distensibility (RAC/pulse pressure from RHC), right ventricular functional indices, and right ventricular mass were all derived. Regression curve fitting identified the statistical model of best fit between RHC measurements and pulmonary artery stiffness indices. The diagnostic accuracy and prognostic value of noninvasive AC and RAC were also assessed. The relationship between pulmonary vascular resistance and pulmonary artery RAC was best reflected by an inverse linear model. Patients with mild elevation in pulmonary vascular resistance (<4 Woods units) demonstrated reduced RAC (P = 0.02) and increased right ventricular mass index (P < 0.0001) without significant loss of right ventricular function (P = 0.17). At follow-up of 0 to 40 months, 18 patients with PH had died (16%). Analysis of Kaplan-Meier plots showed that both AC and RAC predicted mortality (log-rank test, P = 0.046 and P = 0.012, respectively). Area change and RAC were also predictors of mortality using univariate Cox proportional hazards regression analysis (P = 0.046 and P = 0.03, respectively). Noninvasive assessment of pulmonary artery RAC is a marker sensitive to early increased vascular resistance in PH and is a predictor of adverse outcome.
The forecast for RAC extrapolation: mostly cloudy.

PubMed

Goldman, Elizabeth; Jacobs, Robert; Scott, Ellen; Scott, Bonnie

2011-09-01

The current statutory and regulatory guidance for recovery audit contractor (RAC) extrapolation leaves providers with minimal protection against the process and a limited ability to challenge overpayment demands. Providers not only should understand the statutory and regulatory basis for extrapolation forecast, but also should be able to assess their extrapolation risk and their recourse through regulatory safeguards against contractor error. Providers also should aggressively appeal all incorrect RAC denials to minimize the potential impact of extrapolation.
Heavy metal contamination and risk assessment in water, paddy soil, and rice around an electroplating plant.

PubMed

Liu, Jie; Zhang, Xue-Hong; Tran, Henry; Wang, Dun-Qiu; Zhu, Yi-Nian

2011-11-01

The objective of this paper is to assess the impact of long-term electroplating industrial activities on heavy metal contamination in agricultural soils and potential health risks for local residents. Water, soil, and rice samples were collected from sites upstream (control) and downstream of the electroplating wastewater outlet. The concentrations of heavy metals were determined by an atomic absorption spectrophotometer. Fractionation and risk assessment code (RAC) were used to evaluate the environmental risks of heavy metals in soils. The health risk index (HRI) and hazard index (HI) were calculated to assess potential health risks to local populations through rice consumption. Hazardous levels of Cu, Cr, and Ni were observed in water and paddy soils at sites near the plant. According to the RAC analysis, the soils showed a high risk for Ni and a medium risk for Cu and Cr at certain sites. The rice samples were primarily contaminated with Ni, followed by Cr and Cu. HRI values >1 were not found for any heavy metal. However, HI values for adults and children were 2.075 and 1.808, respectively. Water, paddy soil, and rice from the studied area have been contaminated by Cu, Cr, and Ni. The contamination of these elements is related to the electroplating wastewater. Although no single metal poses health risks for local residents through rice consumption, the combination of several metals may threaten the health of local residents. Cu and Ni are the key components contributing to the potential health risks.
The impact of RAC audits on US hospitals.

PubMed

Harrison, Jeffrey P; Barksdale, Rachel M

2013-01-01

The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) authorized a three-year demonstration program using recovery audit contractors (RACs) to identify and correct improper payments in the Medicare Fee-For-Service program. More recently, Section 6411 of the Affordable Care Act (ACA) expanded the RAC program to include the Medicaid program. This shows the Cent ers for Medicare & Medicaid Services (CMS) believe RAC audits are a cost-effective method to ensure health care providers are paid correctly and thereby protect the Medicare Trust Fund. RAC audits are highly complex and require significant manpower to handle the large volume of requests received during a short period of time. Additionally, the RAC audit appeal process is complicated and requires a high level of technical expertise. The demonstration project found that RAC audits resulted in sizeable amounts of overpayments collected ("take-backs") from many providers. This research study assesses the potential impact of the RAC audit program on US acute care hospitals. Data obtained from CMS show that RAC overpayments collected for FY 2010 were $75.4 million, increased to $797.4 million in FY 2011, and increased to $986.2 million in the first six months of FY 2012. According to the American Hospital Association (AHA) RACTrac audit survey, the vast majority of these collections represent complex denials where hospitals are required to provide medical record documents in support of their billed claims. This study found that the RAC audit program collections are increasing significantly over time. As a result, these collections are having a significant negative impact on the profitability of US hospitals.
Multi-factor Effects on the Durability of Recycle Aggregate Concrete

NASA Astrophysics Data System (ADS)

Ma, Huan; Cui, Yu-Li; Zhu, Wen-Yu; Xie, Xian-Jie

2016-05-01

Recycled Aggregate Concrete (RAC) was prepared with different recycled aggregate replacement ratio, 0, 30%, 70% and 100% respectively. The performances of RAC were examined by the freeze-thaw cycle, carbonization and sulfate attack to assess the durability. Results show that test sequence has different effects on the durability of RAC; the durability is poorer when carbonation experiment was carried out firstly, and then other experiment was carried out again; the durability is better when recycled aggregate replacement ratio is 70%.
Flavin-Dependent Redox Transfers by the Two-Component Diketocamphane Monooxygenases of Camphor-Grown Pseudomonas putida NCIMB 10007

PubMed Central

Willetts, Andrew; Kelly, David

2016-01-01

The progressive titres of key monooxygenases and their requisite native donors of reducing power were used to assess the relative contribution of various camphor plasmid (CAM plasmid)- and chromosome-coded activities to biodegradation of (rac)-camphor at successive stages throughout growth of Pseudomonas putida NCIMB 10007 on the bicylic monoterpenoid. A number of different flavin reductases (FRs) have the potential to supply reduced flavin mononucleotide to both 2,5- and 3,6-diketocamphane monooxygenase, the key isoenzymic two-component monooxygenases that delineate respectively the (+)- and (−)-camphor branches of the convergent degradation pathway. Two different constitutive chromosome-coded ferric reductases able to act as FRs can serve such as role throughout all stages of camphor-dependent growth, whereas Fred, a chromosome-coded inducible FR can only play a potentially significant role in the relatively late stages. Putidaredoxin reductase, an inducible CAM plasmid-coded flavoprotein that serves an established role as a redox intermediate for plasmid-coded cytochrome P450 monooxygenase also has the potential to serve as an important FR for both diketocamphane monooxygenases (DKCMOs) throughout most stages of camphor-dependent growth. PMID:27754389

Carbon-Ion Irradiation Suppresses Migration and Invasiveness of Human Pancreatic Carcinoma Cells MIAPaCa-2 via Rac1 and RhoA Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fujita, Mayumi; Imadome, Kaori; Shoji, Yoshimi

2015-09-01

Purpose: To investigate the mechanisms underlying the inhibition of cancer cell migration and invasion by carbon (C)-ion irradiation. Methods and Materials: Human pancreatic cancer cells MIAPaCa-2, AsPC-1, and BxPC-3 were treated by x-ray (4 Gy) or C-ion (0.5, 1, 2, or 4 Gy) irradiation, and their migration and invasion were assessed 2 days later. The levels of guanosine triphosphate (GTP)-bound Rac1 and RhoA were determined by the active GTPase pull-down assay with or without a proteasome inhibitor, and the binding of E3 ubiquitin ligase to GTP-bound Rac1 was examined by immunoprecipitation. Results: Carbon-ion irradiation reduced the levels of GTP-bound Rac1 and RhoA, 2more » major regulators of cell motility, in MIAPaCa-2 cells and GTP-bound Rac1 in AsPC-1 and BxPC-3 cells. Proteasome inhibition reversed the effect, indicating that C-ion irradiation induced Rac1 and RhoA degradation via the ubiquitin (Ub)-proteasome pathway. E3 Ub ligase X-linked inhibitor of apoptosis protein (XIAP), which directly targets Rac1, was selectively induced in C-ion–irradiated MIAPaCa-2 cells and coprecipitated with GTP-bound Rac1 in C-ion–irradiated cells, which was associated with Rac1 ubiquitination. Cell migration and invasion reduced by C-ion radiation were restored by short interfering RNA–mediated XIAP knockdown, indicating that XIAP is involved in C-ion–induced inhibition of cell motility. Conclusion: In contrast to x-ray irradiation, C-ion treatment inhibited the activity of Rac1 and RhoA in MIAPaCa-2 cells and Rac1 in AsPC-1 and BxPC-3 cells via Ub-mediated proteasomal degradation, thereby blocking the motility of these pancreatic cancer cells.« less
Assessment of commercially available energy-efficient room air conditioners including models with low global warming potential (GWP) refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, N. K.; Park, W. Y.; Gerke, B.

Improving the energy efficiency of room air conditioners (RACs) while transitioning to low global-warming-potential (GWP) refrigerants will be a critical step toward reducing the energy, peak load, and emissions impacts of RACs while keeping costs low. Previous research quantified the benefits of leapfrogging to high efficiency in tandem with the transition to low-GWP refrigerants for RACs (Shah et al., 2015) and identified opportunities for initial action to coordinate energy efficiency with refrigerant transition in economies constituting about 65% of the global RAC market (Shah et al., 2017). This report describes further research performed to identify the best-performing (i.e., most efficientmore » and low-GWP-refrigerant using) RACs on the market, to support an understanding of the best available technology (BAT). Understanding BAT can help support market-transformation programs for high-efficiency and low-GWP equipment such as minimum energy performance standards (MEPS), labeling, procurement, and incentive programs. We studied RACs available in six economies—China, Europe, India, Japan, South Korea, and the United States—that together account for about 70% of global RAC demand, as well as other emerging economies. The following are our key findings: • Highly efficient RACs using low-GWP refrigerants, e.g., HFC-32 (R-32) and HC-290 (R-290), are commercially available today at prices comparable to similar RACs using high-GWP HCFC-22 (R-22) or HFC-410A (R-410A). • High efficiency is typically a feature of high-end products. However, highly efficient, cost-competitive (less than 1,000 or 1,500 U.S. dollars in retail price, depending on size) RACs are available. • Where R-22 is being phased out, high GWP R-410A still dominates RAC sales in most mature markets except Japan, where R-32 dominates. • In all of the economies studied except Japan, only a few models are energy efficient and use low-GWP refrigerants. For example, in Europe, India, and Indonesia, the highest-efficiency RAC models employ the low-GWP refrigerants R-32 or R-290. • RACs are available in most regions and worldwide that surpass the highest efficiency levels recognized by labeling programs. • Fixed-speed RACs using high-GWP and ozone-depleting R-22 refrigerant still dominate the market in many emerging economies. There is significant scope to improve RAC efficiency and transition to low-GWP refrigerants using commercially available technology and to design market-transformation programs for high-efficiency, low-GWP equipment including standards, labeling, procurement, and incentive programs.« less
Enhancement of DRPE performance with a novel scheme based on new RAC: Principle, security analysis and FPGA implementation

NASA Astrophysics Data System (ADS)

Neji, N.; Jridi, M.; Alfalou, A.; Masmoudi, N.

2016-02-01

The double random phase encryption (DRPE) method is a well-known all-optical architecture which has many advantages especially in terms of encryption efficiency. However, the method presents some vulnerabilities against attacks and requires a large quantity of information to encode the complex output plane. In this paper, we present an innovative hybrid technique to enhance the performance of DRPE method in terms of compression and encryption. An optimized simultaneous compression and encryption method is applied simultaneously on the real and imaginary components of the DRPE output plane. The compression and encryption technique consists in using an innovative randomized arithmetic coder (RAC) that can well compress the DRPE output planes and at the same time enhance the encryption. The RAC is obtained by an appropriate selection of some conditions in the binary arithmetic coding (BAC) process and by using a pseudo-random number to encrypt the corresponding outputs. The proposed technique has the capabilities to process video content and to be standard compliant with modern video coding standards such as H264 and HEVC. Simulations demonstrate that the proposed crypto-compression system has presented the drawbacks of the DRPE method. The cryptographic properties of DRPE have been enhanced while a compression rate of one-sixth can be achieved. FPGA implementation results show the high performance of the proposed method in terms of maximum operating frequency, hardware occupation, and dynamic power consumption.
Integrated Assessment of Heavy Metal Pollution in the Surface Sediments of the Laizhou Bay and the Coastal Waters of the Zhangzi Island, China: Comparison among Typical Marine Sediment Quality Indices

PubMed Central

Zhuang, Wen; Gao, Xuelu

2014-01-01

The total concentrations and chemical forms of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the surface sediments of the Laizhou Bay and the surrounding marine area of the Zhangzi Island (hereafter referred to as Zhangzi Island for short) were obtained and multiple indices and guidelines were applied to assess their contamination and ecological risks. The sedimentary conditions were fine in both of the two studied areas according to the marine sediment quality of China. Whereas the probable effects level guideline suggested that Ni might cause adverse biological effects to occur frequently in some sites. All indices used suggested that Cd posed the highest environmental risk in both the Laizhou Bay and the Zhangzi Island, though Cd may unlikely be harmful to human and ecological health due to the very low total concentrations. The enrichment factor (EF) showed that a substantial portion of Cr was delivered from anthropogenic sources, whereas the risk assessment code (RAC) indicated that most Cr was in an inactive state that it may not have any adverse effect either. Moreover, the results of EF and geoaccumulation index were consistent with the trend of the total metal concentrations except for Cd, while the results of RAC and potential ecological risk factor did not follow the same trend of their corresponding total metal concentrations. We also evaluated the effects of using different indices to assess the environmental impact of these heavy metals. PMID:24709993
6-Mercaptopurine reduces macrophage activation and gut epithelium proliferation through inhibition of GTPase Rac1.

PubMed

Marinković, Goran; Hamers, Anouk A J; de Vries, Carlie J M; de Waard, Vivian

2014-09-01

Inflammatory bowel disease is characterized by chronic intestinal inflammation. Azathioprine and its metabolite 6-mercaptopurine (6-MP) are effective immunosuppressive drugs that are widely used in patients with inflammatory bowel disease. However, established understanding of their immunosuppressive mechanism is limited. Azathioprine and 6-MP have been shown to affect small GTPase Rac1 in T cells and endothelial cells, whereas the effect on macrophages and gut epithelial cells is unknown. Macrophages (RAW cells) and gut epithelial cells (Caco-2 cells) were activated by cytokines and the effect on Rac1 signaling was assessed in the presence or absence of 6-MP. Rac1 is activated in macrophages and epithelial cells, and treatment with 6-MP resulted in Rac1 inhibition. In macrophages, interferon-γ induced downstream signaling through c-Jun-N-terminal Kinase (JNK) resulting in inducible nitric oxide synthase (iNOS) expression. iNOS expression was reduced by 6-MP in a Rac1-dependent manner. In epithelial cells, 6-MP efficiently inhibited tumor necrosis factor-α-induced expression of the chemokines CCL2 and interleukin-8, although only interleukin-8 expression was inhibited in a Rac1-dependent manner. In addition, activation of the transcription factor STAT3 was suppressed in a Rac1-dependent fashion by 6-MP, resulting in reduced proliferation of the epithelial cells due to diminished cyclin D1 expression. These data demonstrate that 6-MP affects macrophages and gut epithelial cells beneficially, in addition to T cells and endothelial cells. Furthermore, mechanistic insight is provided to support development of Rac1-specific inhibitors for clinical use in inflammatory bowel disease.
The Role of Rac1 on Carbachol-induced Contractile Activity in Detrusor Smooth Muscle from Streptozotocin-induced Diabetic Rats.

PubMed

Evcim, Atiye Sinem; Micili, Serap Cilaker; Karaman, Meral; Erbil, Guven; Guneli, Ensari; Gidener, Sedef; Gumustekin, Mukaddes

2015-06-01

This study was designed to determine the role of the small GTPase Rac1 on carbachol-induced contractile activity in detrusor smooth muscle using small inhibitor NSC 23766 in diabetic rats. Rac1 expression in bladder tissue was also evaluated. In the streptozotocin (STZ)-induced diabetic rat model, three study groups were composed of control, diabetic and insulin-treated diabetic subjects. The detrusor muscle strips were suspended in organ baths at the end of 8-12 weeks after STZ injection. Carbachol (CCh) (10(-9) -10(-4) M) concentration-response curves were obtained both in the absence and in the presence of Rac1 inhibitor NSC 23766 (0.1, 1 and 10 μM). Diabetes-related histopathological changes and Rac1 expressions were assessed by haematoxylin and eosin staining and immunohistochemical staining, respectively. CCh caused dose-dependent contractile responses in all the study groups. Rac1 inhibitor NSC 23766 inhibited CCh-induced contractile responses in all groups, but this inhibition seen in both diabetes groups was greater than in the control group. Histological examination revealed an increased bladder wall thickness both in the diabetes and in the insulin-treated diabetes groups compared to the control group. In immunohistochemical staining, expression of Rac1 was observed to be increased in all layers of bladder in both diabetic groups compared to the control group. In the diabetic bladders, increased expression of Rac1 and considerable inhibition of CCh-induced responses in the presence of NSC 23766 compared to those of the control group may indicate a specific role of Rac1 in diabetes-related bladder dysfunction, especially associated with cholinergic mediated detrusor overactivity. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).
Interleukin (IL)-1 in rat parturition: IL-1 receptors 1 and 2 and accessory proteins abundance in pregnant rat uterus at term - regulation by progesterone.

PubMed

Ishiguro, Tomohito; Takeda, Jun; Fang, Xin; Bronson, Heather; Olson, David M

2016-07-01

The role of interleukin-1 (IL-1), a pro-inflammatory cytokine, in parturition is typically noted by changes in its concentrations. Studying the expression of its receptor family, IL-1 receptor (IL-1R) 1, IL-1R2, IL-1R accessory protein (IL-1RAcP), and its predominantly brain isoform, IL-1RAcPb, during late gestation in the uterus in the Long-Evans rat is another. We assessed changes in their mRNA and protein relative abundance in the uterus and compared IL-1RAcP and IL-1RAcPb mRNA abundance in uterus, cervix, ovaries, placenta, and whole blood of Long-Evans rats during late gestation or in RU486 and progesterone-treated dams using quantitative real-time PCR and western immunoblotting. IL-1R1, IL-1RAcP, and IL-1RAcPb mRNA abundance significantly increased in the uterus at delivery whereas IL-1R2 mRNA abundance significantly decreased. IL-1R1 protein increased at term and IL-1R2 protein decreased at term compared to nonpregnant uteri. IL1-RAcPb mRNA abundance was less than IL-1RAcP, but in the lower uterine segment it was the highest of all tissues examined. RU486 stimulated preterm delivery and an increase in IL-1R1 mRNA abundance whereas progesterone administration extended pregnancy and suppressed the increase in IL-1R1. These data suggest that changes in uterine sensitivity to IL-1 occur during late gestation and suggest another level of regulation for the control of delivery. The roles for IL-1RAcP and IL-1RAcPb need to be determined, but may relate to different intracellular signaling pathways. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
Pacific Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

This report represents the deliberations of the Pacific Regional Advisory Committee (RAC), one of 10 RACs established under the Educational Technical Assistance Act of 2002 to assess the educational needs of the region. The committee's report outlines educational needs across the state, districts, and territories of Hawai'i, the Commonwealth of…
Transformative Learning: Immigrant Learners Who Participated in Recognition of Acquired Competencies (RAC)

ERIC Educational Resources Information Center

Moss, Leah; Brown, Andy

2014-01-01

Recognition of Acquired Competencies (RAC) as it is known in Quebec, Canada, or Prior Learning Assessment (PLA), requires a learner to engage in retrospective thought about their learning path, their learning style and their experiential knowledge. This process of critical self-reflection and rigorous analysis by the learner of their prior…
Stochastic Plume Simulations for the Fukushima Accident and the Deep Water Horizon Oil Spill

NASA Astrophysics Data System (ADS)

Coelho, E.; Peggion, G.; Rowley, C.; Hogan, P.

2012-04-01

The Fukushima Dai-ichi power plant suffered damage leading to radioactive contamination of coastal waters. Major issues in characterizing the extent of the affected waters were a poor knowledge of the radiation released to the coastal waters and the rather complex coastal dynamics of the region, not deterministically captured by the available prediction systems. Equivalently, during the Gulf of Mexico Deep Water Horizon oil platform accident in April 2010, significant amounts of oil and gas were released from the ocean floor. For this case, issues in mapping and predicting the extent of the affected waters in real-time were a poor knowledge of the actual amounts of oil reaching the surface and the fact that coastal dynamics over the region were not deterministically captured by the available prediction systems. To assess the ocean regions and times that were most likely affected by these accidents while capturing the above sources of uncertainty, ensembles of the Navy Coastal Ocean Model (NCOM) were configured over the two regions (NE Japan and Northern Gulf of Mexico). For the Fukushima case tracers were released on each ensemble member; their locations at each instant provided reference positions of water volumes where the signature of water released from the plant could be found. For the Deep Water Horizon oil spill case each ensemble member was coupled with a diffusion-advection solution to estimate possible scenarios of oil concentrations using perturbed estimates of the released amounts as the source terms at the surface. Stochastic plumes were then defined using a Risk Assessment Code (RAC) analysis that associates a number from 1 to 5 to each grid point, determined by the likelihood of having tracer particle within short ranges (for the Fukushima case), hence defining the high risk areas and those recommended for monitoring. For the Oil Spill case the RAC codes were determined by the likelihood of reaching oil concentrations as defined in the Bonn Agreement Oil Appearance Code. The likelihoods were taken in both cases from probability distribution functions derived from the ensemble runs. Results were compared with a control-deterministic solution and checked against available reports to assess their skill in capturing the actual observed plumes and other in-situ data, as well as their relevance for planning surveys and reconnaissance flights for both cases.
New values anthropometry for classification of nutritional status in the elderly.

PubMed

Silva Rodrigues, R A; Martinez Espinosa, M; Duarte Melo, C; Rodrigues Perracini, M; Rezende Fett, W C; Fett, C A

2014-07-01

Anthropometry provides information on the physical status of the individual and can be associated with aspects of health including nutritional status. Currently, the stratification of the arm and calf circumferences is classified into only two situations: "malnourished" and "well-nourished". A total of 513 interviews were conducted, and 391 elderly people (≥ 65 years) completed the assessment using the Mini Nutritional Assessment (MNA) and anthropometry of selected samples of the population of Cuiabá-MT. The body mass index (BMI, kg/m2) was calculated for the elderly people, establishing five new reference values for circumferences, arm relaxed (RAC), abdomen (AC), and calf (CC) in centimeters (cm). The median age was 71 years (64% women and 36% men) and was correlated to the RAC (r=-0.180, p<0.001) and CC (r=-0.202, pp<0.001). The BMI obtained the median of 27 (15% malnourished, risk of malnutrition 13%, eutrophic 24%; overweight 33%, obese 16%), and it was correlated to the RAC (r=0.798, pp<0.001), AC (r=0.823 p p<0.001) and CC (r=0.605, pp<0.001). The MNA was 26 (malnourished 13.8%, risk of malnutrition 12.3%, well-nourished, 73.9%). The BMI stratification by morbidity vs no morbidity was 27.50 (n=287) and 24.4 (n=104) to total sample respectively (pp<0,05). The RAC x AC (r=0.798, pp<0.001), RAC x CC (r=0.648, pp<0.001), and CC x AC (r=0.496, pp<0.001) were correlated between themselves. The eutrophic classification by circumference for both genders: RAC=27.1-29.00 cm, AC=88.1-95.00 cm, CC=32.60-33.00 cm. There are more overweight and obese than malnourished, which is a risk factor for morbidity and MNA only identifies malnutrition. Circumferences showed good association with BMI and are easy to apply. Therefore, the proposal of the circumferences can simplify and expand the nutritional assessment.
Appalachian Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

This report presents the deliberations of the Appalachia Regional Advisory Committee (Appalachia RAC), one of 10 RACs established under the Educational Technical Assistance Act of 2002 (20 U.S.C. sections 9601 et. seq.) to assess the educational needs of the region. The Committee's report outlines the educational needs across the four states of…
Midwest Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

This report presents the deliberations of the Midwest Regional Advisory Committee (MW RAC), one of 10 RACs established under the Educational Technical Assistance Act of 2002 (20 U.S.C. sections 9601 et. seq.) to assess the educational needs of the region. The committee's report outlines the educational needs across the seven states of Illinois,…
Central Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

This report presents the deliberations of the Central Regional Advisory Committee (RAC), one of 10 RACs established under the Educational Technical Assistance Act of 2002 (20 U.S.C. sections 9601 et. seq.) to assess the educational needs of the region. The committee's report outlines the educational needs across the states of Colorado, Kansas,…
Mid-Atlantic Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

This report presents the deliberations of the Mid-Atlantic Regional Advisory Committee (RAC), one of 10 RACs established under the Educational Technical Assistance Act of 2002 (20 U.S.C. sections 9601 et. seq.) to assess the educational needs of the region. The committee's report outlines the educational needs across the District of Columbia and…
Assessment of heavy metal pollution, spatial distribution and origin in agricultural soils along the Sinú River Basin, Colombia.

PubMed

Marrugo-Negrete, José; Pinedo-Hernández, José; Díez, Sergi

2017-04-01

The presence of metals in agricultural soils from anthropogenic activities such as mining and agricultural use of metals and metal-containing compounds is a potential threat for human health through the food chain. In this study, the concentration of heavy metals in 83 agricultural soils irrigated by the Sinú River, in northern Colombia, affected by mining areas upstream and inundated during seasonal floods events were determined to evaluate their sources and levels of pollution. The average concentrations of Cu, Ni, Pb, Cd, Hg and Zn were 1149, 661, 0.071, 0.040, 0.159 and 1365mg/kg respectively and exceeded the world normal averages, with the exception of Pb and Cd. Moreover, all values surpassed the background levels of soils in the same region. Soil pollution assessment was carried out using contamination factor (CF), enrichment factor (EF), geoaccumulation index (Igeo) and a risk assessment code (RAC). According to these indexes, the soils show a high degree of pollution of Ni and a moderate to high contamination of Zn and Cu; whereas, Pb, Cd and Hg present moderate pollution. However, based on the RAC index, a low environmental risk is found for all the analysed heavy metals. Multivariate statistical analyses, principal component and cluster analyses, suggest that soil contamination was mainly derived from agricultural practices, except for Hg, which was caused probably by atmospheric and river flow transport from upstream gold mining. Finally, high concentrations of Ni indicate a mixed pollution source from agricultural and ferronickel mining activities. Copyright © 2017 Elsevier Inc. All rights reserved.
Mena associates with Rac1 and modulates connexin 43 remodeling in cardiomyocytes

PubMed Central

Ram, Rashmi; Wescott, Andrew P.; Varandas, Katherine; Dirksen, Robert T.

2013-01-01

Mena, a member of the Ena/VASP family of actin regulatory proteins, modulates microfilaments and interacts with cytoskeletal proteins associated with heart failure. Mena is localized at the intercalated disc (ICD) of adult cardiac myocytes, colocalizing with numerous cytoskeletal proteins. Mena's role in the maintainence of mechanical myocardial stability at the cardiomyocyte ICD remains unknown. We hypothesized that Mena may modulate signals from the sarcolemma to the actin cytoskeleton at the ICD to regulate the expression and localization of connexin 43 (Cx43). The small GTPase Rac1 plays a pivotal role in the regulation of actin cytoskeletal reorganization and mediating morphological and transcriptional changes in cardiomyocytes. We found that Mena is associated with active Rac1 in cardiomyocytes and that RNAi knockdown of Mena increased Rac1 activity significantly. Furthermore, Mena knockdown increased Cx43 expression and altered Cx43 localization and trafficking at the ICD, concomitant with faster intercellular communication, as assessed by dye transfer between cardiomyocyte pairs. In mice overexpressing constitutively active Rac1, left ventricular Mena expression was increased significantly, concomitant with lateral redistribution of Cx43. These results suggest that Mena is a critical regulator of the ICD and is required for normal localization of Cx43 in part via regulation of Rac1. PMID:24186093
Mena associates with Rac1 and modulates connexin 43 remodeling in cardiomyocytes.

PubMed

Ram, Rashmi; Wescott, Andrew P; Varandas, Katherine; Dirksen, Robert T; Blaxall, Burns C

2014-01-01

Mena, a member of the Ena/VASP family of actin regulatory proteins, modulates microfilaments and interacts with cytoskeletal proteins associated with heart failure. Mena is localized at the intercalated disc (ICD) of adult cardiac myocytes, colocalizing with numerous cytoskeletal proteins. Mena's role in the maintainence of mechanical myocardial stability at the cardiomyocyte ICD remains unknown. We hypothesized that Mena may modulate signals from the sarcolemma to the actin cytoskeleton at the ICD to regulate the expression and localization of connexin 43 (Cx43). The small GTPase Rac1 plays a pivotal role in the regulation of actin cytoskeletal reorganization and mediating morphological and transcriptional changes in cardiomyocytes. We found that Mena is associated with active Rac1 in cardiomyocytes and that RNAi knockdown of Mena increased Rac1 activity significantly. Furthermore, Mena knockdown increased Cx43 expression and altered Cx43 localization and trafficking at the ICD, concomitant with faster intercellular communication, as assessed by dye transfer between cardiomyocyte pairs. In mice overexpressing constitutively active Rac1, left ventricular Mena expression was increased significantly, concomitant with lateral redistribution of Cx43. These results suggest that Mena is a critical regulator of the ICD and is required for normal localization of Cx43 in part via regulation of Rac1.
Rac1 and Rac3 have opposing functions in cell adhesion and differentiation of neuronal cells.

PubMed

Hajdo-Milasinović, Amra; Ellenbroek, Saskia I J; van Es, Saskia; van der Vaart, Babet; Collard, John G

2007-02-15

Rac1 and Rac3 are highly homologous members of the Rho small GTPase family. Rac1 is ubiquitously expressed and regulates cell adhesion, migration and differentiation in various cell types. Rac3 is primarily expressed in brain and may therefore have a specific function in neuronal cells. We found that depletion of Rac1 by short interference RNA leads to decreased cell-matrix adhesions and cell rounding in neuronal N1E-115 cells. By contrast, depletion of Rac3 induces stronger cell adhesions and dramatically increases the outgrowth of neurite-like protrusions, suggesting opposite functions for Rac1 and Rac3 in neuronal cells. Consistent with this, overexpression of Rac1 induces cell spreading, whereas overexpression of Rac3 results in a contractile round morphology. Rac1 is mainly found at the plasma membrane, whereas Rac3 is predominantly localized in the perinuclear region. Residues 185-187, present in the variable polybasic rich region at the carboxyl terminus are responsible for the difference in phenotype induced by Rac1 and Rac3 as well as for their different intracellular localization. The Rac1-opposing function of Rac3 is not mediated by or dependent on components of the RhoA signaling pathway. It rather seems that Rac3 exerts its function through negatively affecting integrin-mediated cell-matrix adhesions. Together, our data reveal that Rac3 opposes Rac1 in the regulation of cell adhesion and differentiation of neuronal cells.
R-Matrix Codes for Charged-Particle Induced Reactions in the Resolved Resonance Region (3), Summary Report of an IAEA Consultants' Meeting IAEA Headquarters, Vienna, Austria, 28-30 June 2017

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leeb, Helmut; Dimitriou, Paraskevi; Thompson, Ian

A Consultants Meeting was held at the IAEA Headquarters, from 28 to 30 June 2017, to discuss the results of a test exercise that had been defined and assigned to all participants of the previous meeting held in December 2016. Five codes were used in this exercise: AMUR, AZURE2, RAC, SFRESCO and SAMMY. The results obtained from these codes were compared and further actions were proposed. Participants’ presentations and technical discussions, as well as proposed additional actions have been summarized in this report.

Assessment of the Activation of Rho Family GTP-Binding Proteins in Breast Cancer Cells and Specimens

DTIC Science & Technology

2001-08-01

lymphopenia Vav2 GEF for Rho, Rac, and Cdc42 proto-oncogene product; NM009500 Vav3 GEF for Rho and Rac proto-oncogene product; NM020505 hPEM -2 GEF for...junctions, and desmosomes play a fundamental role in maintaining the polarized phenotype and vectorial transport functions of epithelial cells. The tight
Rabeprazole- versus esomeprazole-based eradication regimens for H. pylori infection.

PubMed

Wu, I-Chen; Wu, Deng-Chyang; Hsu, Ping-I; Lu, Chien-Yu; Yu, Fang-Jung; Wang, Tsang-En; Chang, Wen-Hsiung; Chen, Jyh-Jon; Kuo, Fu-Chen; Wu, Jeng-Yih; Wang, Wen-Ming; Bair, Ming-Jong

2007-12-01

Different kinds of proton pump inhibitor-based triple therapies could result in different Helicobacter pylori eradication rates. The aims of this study were to compare the efficacy and safety of rabeprazole- and esomeprazole-based triple therapy in primary treatment of H. pylori infection in Taiwan. From June 2005 to March 2007, 420 H. pylori-infected patients were randomly assigned to receive a 7-day eradication therapy with either esomeprazole 40 mg daily (EAC group, n = 209) or rabeprazole 20 mg b.i.d. (RAC group, n = 211) in combination with amoxicillin 1 g b.i.d. and clarithromycin 500 mg b.i.d.. Follow-up endoscopy with biopsy was done 12-16 weeks after completion of eradication therapy. Those who refused endoscopic exams underwent (13)C-urea breath test to assess the treatment response. Intention-to-treat analysis revealed that the eradication rate was 89.4% in the EAC group and 90.5% in RAC groups (p-value = .72). All of the subjects returned for assessment of compliance (100% in EAC group vs. 99.5% in RAC group, p-value = .32) and adverse events (3.83% in EAC group vs. 6.16% in RAC group, p-value = .27). Sixty (28.7%) and 37 (17.6%) patients in EAC and RAC group, respectively, refused endoscopy and underwent a (13)C-urea breath test to determine the treatment effect. In conclusion, rabeprazole- and esomeprazole-based primary therapies for H. pylori infection are comparable in efficacy and safety.
Assessment of the Activation State of Rho Family GTP-Binding Proteins in Breast Cancer Cells and Specimens

DTIC Science & Technology

2004-08-01

AF038388 Vav3 GEF for Rho and Rac Proto-oncogene product NM020505 hPEM -2 GEF for Cdc42 Predominantly expressed in brain AB007884 GEF-H1 GEF for Rac and Rho...fence tions, and desmosomes play a fundamental role in maintain- function). A functional tight junction is crucial to maintain ing the polarized phenotype
Conflict Prediction Through Geo-Spatial Interpolation of Radicalization in Syrian Social Media

DTIC Science & Technology

2015-09-24

TRAC-M-TM-15-031 September 2015 Conflict Prediction Through Geo-Spatial Interpolation of Radicalization in Syrian Social Media ...Spatial Interpolation of Radicalization in Syrian Social Media Authors MAJ Adam Haupt Dr. Camber Warren...Spatial Interpolation of Radicalization in Syrian Social 1RAC Project Code 060114 Media 6. AUTHOR(S) MAJ Haupt, Dr. Warren 7. PERFORMING OR
Effect of ractopamine hydrochloride (Optaflexx) dose and duration on growth performance and carcass characteristics of finishing steers.

PubMed

Bittner, C J; Crawford, G I; Berger, L L; Holt, S; Pritchard, R R; Platter, W J; Van Koevering, M T; Pyatt, N A; Erickson, G E

2016-12-01

Three experiments evaluated the effects of ractopamine hydrochloride (RAC) dose and duration on growth performance and carcass characteristics of feedlot steers. In total, 1,509 crossbred steers (530 kg initial BW [SD 22]) were used in a randomized complete block design using a 3 × 3 factorial treatment structure. Treatments consisted of RAC dose (0, 100, or 200 mg/steer daily) and duration (28, 35, or 42 d) of RAC feeding prior to harvest. Initiation of RAC dose was staggered (7 d apart) based on RAC duration, which resulted in common days on feed among treatments. Data from the 3 experiments were combined for statistical analyses. There were no RAC dose × duration interactions ( ≥ 0.85) for growth performance. Live final BW was not different ( ≥ 0.24) as RAC dose increased. Dry matter intake linearly decreased ( < 0.01) as RAC dose increased. Live ADG and G:F linearly increased ( ≤ 0.01) as RAC dose increased. Carcass-adjusted ADG and G:F linearly increased ( ≤ 0.02) as RAC dose increased. Compared with steers fed 0 mg RAC/steer daily, G:F was improved by 5.0 and 13.0% when steers were fed 100 ( = 0.31) and 200 ( = 0.01) mg RAC/steer daily, respectively. Hot carcass weight tended ( = 0.10) to linearly increase as RAC dose increased, with carcasses from steers fed 100 ( = 0.38) and 200 ( = 0.10) mg RAC/steer daily being 2.2 and 4.1 kg heavier, respectively, than carcasses from steers fed 0 mg RAC/steer daily. Increasing RAC dose linearly ( < 0.01) increased LM area and linearly ( = 0.02) decreased marbling score. Live final BW was not different ( ≥ 0.60) among RAC durations. Carcass-adjusted final BW, ADG, and G:F were not different ( ≥ 0.41) as RAC duration increased. Carcass traits did not differ ( ≥ 0.18) among RAC duration. Feeding 200 mg RAC/steer daily improved ADG, feed efficiency, and HCW. Increasing the feeding duration of RAC had no effect of growth performance or carcass characteristics. These data indicate that feeding 200 mg RAC/steer daily for 28 d improves steer growth performance.
Rac2 Functions in Both Neutrophils and Macrophages To Mediate Motility and Host Defense in Larval Zebrafish.

PubMed

Rosowski, Emily E; Deng, Qing; Keller, Nancy P; Huttenlocher, Anna

2016-12-15

Leukocyte motility is required for host defense responses. Rac-family Rho GTPases are implicated in leukocyte function; however, the distinct roles of different Rac isoforms in host defense in vivo have remained unclear. In this study, we generated Rac2-deficient zebrafish using transcription activator-like effector nucleases to directly compare the role of Rac2 in vivo in neutrophils and macrophages in motility and the response to infection. This zebrafish larval model is highly amenable to live imaging of leukocyte behavior, and we report that in rac2 -/- larvae both neutrophils and macrophages are defective in basic motility, leading to impaired responses to localized wounds or infections. rac2 -/- larvae are highly susceptible to infection with Pseudomonas aeruginosa, which can be almost fully rescued by ectopic expression of either Rac2 or Rac1 specifically in neutrophils, indicating that these isoforms have partially overlapping functions in vivo. Rescue of Rac2 expression specifically in macrophages also confers resistance to Pseudomonas infection, highlighting an important role for Rac2 in this leukocyte population as well. Surprisingly, in contrast to neutrophils expressing a Rac2 dominant inhibitory human disease mutation, rac2 -/- neutrophils do not have altered polarity or mobilization from hematopoietic tissue, suggesting that a different Rac isoform, such as Rac1, also contributes to these phenotypes in vivo. Copyright © 2016 by The American Association of Immunologists, Inc.
Loss of Either Rac1 or Rac3 GTPase Differentially Affects the Behavior of Mutant Mice and the Development of Functional GABAergic Networks

PubMed Central

Pennucci, Roberta; Talpo, Francesca; Astro, Veronica; Montinaro, Valentina; Morè, Lorenzo; Cursi, Marco; Castoldi, Valerio; Chiaretti, Sara; Bianchi, Veronica; Marenna, Silvia; Cambiaghi, Marco; Tonoli, Diletta; Leocani, Letizia; Biella, Gerardo; D'Adamo, Patrizia; de Curtis, Ivan

2016-01-01

Rac GTPases regulate the development of cortical/hippocampal GABAergic interneurons by affecting the early development and migration of GABAergic precursors. We have addressed the function of Rac1 and Rac3 proteins during the late maturation of hippocampal interneurons. We observed specific phenotypic differences between conditional Rac1 and full Rac3 knockout mice. Rac1 deletion caused greater generalized hyperactivity and cognitive impairment compared with Rac3 deletion. This phenotype matched with a more evident functional impairment of the inhibitory circuits in Rac1 mutants, showing higher excitability and reduced spontaneous inhibitory currents in the CA hippocampal pyramidal neurons. Morphological analysis confirmed a differential modification of the inhibitory circuits: deletion of either Rac caused a similar reduction of parvalbumin-positive inhibitory terminals in the pyramidal layer. Intriguingly, cannabinoid receptor-1-positive terminals were strongly increased only in the CA1 of Rac1-depleted mice. This increase may underlie the stronger electrophysiological defects in this mutant. Accordingly, incubation with an antagonist for cannabinoid receptors partially rescued the reduction of spontaneous inhibitory currents in the pyramidal cells of Rac1 mutants. Our results show that Rac1 and Rac3 have independent roles in the formation of GABAergic circuits, as highlighted by the differential effects of their deletion on the late maturation of specific populations of interneurons. PMID:26582364
Dynamic Control of Excitatory Synapse Development by a Rac1 GEF/GAP Regulatory Complex

PubMed Central

Um, Kyongmi; Niu, Sanyong; Duman, Joseph G.; Cheng, Jinxuan; Tu, Yen-Kuei; Schwechter, Brandon; Liu, Feng; Hiles, Laura; Narayanan, Anjana; Ash, Ryan T.; Mulherkar, Shalaka; Alpadi, Kannan; Smirnakis, Stelios M.; Tolias, Kimberley F.

2014-01-01

SUMMARY The small GTPase Rac1 orchestrates actin-dependent remodeling essential for numerous cellular processes including synapse development. While precise spatiotemporal regulation of Rac1 is necessary for its function, little is known about the mechanisms that enable Rac1 activators (GEFs) and inhibitors (GAPs) to act in concert to regulate Rac1 signaling. Here we identify a regulatory complex composed of a Rac-GEF (Tiam1) and a Rac-GAP (Bcr) that cooperate to control excitatory synapse development. Disruption of Bcr function within this complex increases Rac1 activity and dendritic spine remodeling, resulting in excessive synaptic growth that is rescued by Tiam1 inhibition. Notably, EphB receptors utilize the Tiam1-Bcr complex to control synaptogenesis. Following EphB activation, Tiam1 induces Rac1-dependent spine formation, whereas Bcr prevents Rac1-mediated receptor internalization, promoting spine growth over retraction. The finding that a Rac-specific GEF/GAP complex is required to maintain optimal levels of Rac1 signaling provides an important insight into the regulation of small GTPases. PMID:24960694
Sanguinarine inhibits Rac1b-rendered cell survival enhancement by promoting apoptosis and blocking proliferation

PubMed Central

Ying, Li; Li, Gang; Wei, Si-si; Wang, Hong; An, Pei; Wang, Xun; Guo, Kai; Luo, Xian-jin; Gao, Ji-min; Zhou, Qing; Li, Wei; Yu, Ying; Li, Yi-gang; Duan, Jun-li; Wang, Yue-peng

2015-01-01

Aim: Small GTPase Rac1 is a member of the Ras superfamily, which plays important roles in regulation of cytoskeleton reorganization, cell growth, proliferation, migration, etc. The aim of this study was to determine how a constitutively active Rac1b regulated cell proliferation and to investigate the effects of the Rac1b inhibitor sanguinarine. Methods: Three HEK293T cell lines stably overexpressing GFP, Rac1-GFP or Rac1b-GFP were constructed by lentiviral infection. The cells were treated with sanguinarine (1 μmol/L) or its analogue berberine (1 μmol/L) for 4 d. Cell proliferation was evaluated by counting cell numbers and with a BrdU incorporation assay. The levels of cleaved PARP-89 (an apoptosis marker) and cyclin-D1 (a proliferative index) were measured using Western blotting. Results: In 10% serum-containing media, overexpressing either Rac1 or Rac1b did not significantly change the cell proliferation. In the serum-starved media, however, the survival rate of Rac1b cells was significantly increased, whereas that of Rac1 cells was moderately increased. The level of cleaved PARP-89 was significantly increased in serum-starved Rac1 cells, but markedly reduced in serum-starved Rac1b cells. The level of cyclin-D1 was significantly increased in both serum-starved Rac1 and Rac1b cells. Treatment with sanguinarine, but not berberine, inhibited the proliferation of Rac1b cells, which was accompanied by significantly increased the level of PARP-89, and decreased both the level of cyclin-D1 and the percentage of BrdU positive cells. Conclusion: Rac1b enhances the cell proliferation under a growth-limiting condition via both anti-apoptotic and pro-proliferative mechanisms. Sanguinarine, as the specific inhibitor of Rac1b, is a potential therapeutic agent for malignant tumors with up-regulated Rac1b. PMID:25544362
Sediment quality assessment in a coastal lagoon (Ravenna, NE Italy) based on SEM-AVS and sequential extraction procedure.

PubMed

Pignotti, Emanuela; Guerra, Roberta; Covelli, Stefano; Fabbri, Elena; Dinelli, Enrico

2018-09-01

Sediments from the Pialassa Piomboni coastal lagoon (NE Italy) were studied to assess the degree of contamination and ecological risk related to trace metals by combining a geochemical characterization of bulk sediments with the assessment of the bioavailable forms of trace metals. With this purpose, sediment contamination (Cd, Cu, Hg, Ni, Pb, and Zn) was assessed by Enrichment Factors (EFs), and potential bioavailability by the Simultaneously Extracted Metals and Acid Volatile Sulfides (SEM-AVS) approach (Cd, Cu, Ni, Pb, and Zn), and by Sequential Extraction Procedure (Co, Cr, Cu, Ni, Pb, and Zn). On average, Cr and Ni exhibited no contamination (EF ≤1.5), and a predominance in the residual fraction of the sediment, indicating natural origin for these metals. Cu, Pb and Zn displayed a local contamination, which resulted in a higher proportion of Cu bound to the reducible and oxidizable fractions (~30% and ~40% as median, respectively), and Pb mostly associated with the reducible phase (~60% as median). Hence, Cu and Pb could be mobilized when environmental conditions become reducing or oxidizing. Zn resulted mainly partitioned into the reducible and residual fractions (~50% as median, in both fractions). The Risk Assessment Code (RAC) indicated that approximately 30% of samples had >10% of total Zn weakly bound to the sediment, suggesting a medium risk of exposure for aquatic organisms. RAC results were consistent with the ∑SEM-AVS findings, pointing to possible adverse effects for aquatic biota in ~30% of samples, with Zn mostly accounting for the total metal bioavailability. Hg showed a moderate to very severe enrichment, indicating that a substantial amount of this metal derives from anthropogenic sources and may pose adverse effects on the aquatic biota of the Pialassa Piomboni lagoon. Copyright © 2018 Elsevier B.V. All rights reserved.
Binding intensity and metal partitioning in soils affected by mining and smelting activities in Minas Gerais, Brazil.

PubMed

Lopes, G; Costa, E T S; Penido, E S; Sparks, D L; Guilherme, L R G

2015-09-01

Mining and smelting activities are potential sources of heavy metal contamination, which pose a threat to human health and ecological systems. This study investigated single and sequential extractions of Zn, Pb, and Cd in Brazilian soils affected by mining and smelting activities. Soils from a Zn mining area (soils A, B, C, D, E, and the control soil) and a tailing from a smelting area were collected in Minas Gerais state, Brazil. The samples were subjected to single (using Mehlich I solution) and sequential extractions. The risk assessment code (RAC), the redistribution index (U ts ), and the reduced partition index (I R ) have been applied to the sequential extraction data. Zinc and Cd, in soil samples from the mining area, were found mainly associated with carbonate forms. This same pattern did not occur for Pb. Moreover, the Fe-Mn oxides and residual fractions had important contributions for Zn and Pb in those soils. For the tailing, more than 70 % of Zn and Cd were released in the exchangeable fraction, showing a much higher mobility and availability of these metals at this site, which was also supported by results of RAC and I R . These differences in terms of mobility might be due to different chemical forms of the metals in the two sites, which are attributable to natural occurrence as well as ore processing.
Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12.

PubMed

Liu, Xiaoxiao; Li, Yangmei; Guo, Yunxue; Zeng, Zhenshun; Li, Baiyuan; Wood, Thomas K; Cai, Xingsheng; Wang, Xiaoxue

2015-11-04

Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions.
Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12

PubMed Central

Liu, Xiaoxiao; Li, Yangmei; Guo, Yunxue; Zeng, Zhenshun; Li, Baiyuan; Wood, Thomas K.; Cai, Xingsheng; Wang, Xiaoxue

2015-01-01

Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions. PMID:26530864
Rac1 Dosage Is Crucial for Normal Endochondral Bone Growth.

PubMed

Suzuki, Dai; Bush, Jason R; Bryce, Dawn-Marie; Kamijo, Ryutaro; Beier, Frank

2017-10-01

Rac1, a member of the small Rho GTPase family, plays multiple cellular roles. Studies of mice conditionally lacking Rac1 have revealed essential roles for Rac1 in various tissues, including cartilage and limb mesenchyme, where Rac1 loss produces dwarfism and long bone shortening. To gain further insight into the role of Rac1 in skeletal development, we have used transgenic mouse lines to express a constitutively active (ca) Rac1 mutant protein in a Cre recombinase-dependent manner. Overexpression of caRac1 in limb bud mesenchyme or chondrocytes leads to reduced body weight and shorter bones compared with control mice. Histological analysis of growth plates showed that caRac1;Col2-Cre mice displayed ectopic hypertrophic chondrocytes in the proliferative zone and enlarged hypertrophic zones. These mice also displayed a reduced proportion of proliferating cell nuclear antigen-positive cells in the proliferative zone and nuclear β-catenin localization in the ectopic hypertrophic chondrocytes. Importantly, overexpression of caRac1 partially rescued the phenotypes of Rac1fl/fl;Col2-Cre and Rac1fl/fl;Prx1-Cre conditional knockout mice, including body weight, bone length, and growth plate disorganization. These results suggest that tight regulation of Rac1 activity is necessary for normal cartilage development. Copyright © 2017 Endocrine Society.
cDNA cloning, expression and immune function analysis of a novel Rac1 gene (AjRac1) in the sea cucumber Apostichopus japonicus.

PubMed

Li, Kaiquan; Liu, Lin; Shang, Shengnan; Wang, Yi; Zhan, Yaoyao; Song, Jian; Zhang, Xiangxiang; Chang, Yaqing

2017-10-01

The ras-related C3 botulinum toxin substrate 1 (Rac1) belongs to Ras homolog (Rho) small GTPases subfamily. As an important molecular switch, Rac1 regulates various processes in the cell, especially in cellular immune response. With attempt to clarify characters and functions of Rac1 in sea cucumbers, full length cDNA of a Rac1 homolog in the sea cucumber Apostichopus japonicus (AjRac1) was cloned by transcriptome database mining and rapid amplification of cDNA ends (RACE) techniques. The open reading frame of AjRac1 is 579 bp encoding a protein with a length of 192 aa. Sequence analysis showed that AjRac1 is highly conserved as compared to those from other eukaryotic species. Phylogenetic analysis revealed that amino acid sequence of AjRac1 closely related to those from Strongylocentrotus purpuratus. Results of expression analysis showed that AjRac1 exhibited a relative high expression in blastula stage, adult coelomocytes and respiratory tree in A. japonicus. The transcription of AjRac1 in adult coelomocytes altered significantly at 4 h- and 12 h-after Vibrio splendidus infection, respectively, which indicated that AjRac1 involved in sea cucumber innate immunity. All data presented in this study will deepen our understanding of characterizations and immunological functions of Rac1 in sea cucumbers. Copyright © 2017 Elsevier Ltd. All rights reserved.
Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate.

PubMed

Muzaffar, S; Shukla, N; Bond, M; Sala-Newby, G B; Newby, A C; Angelini, G D; Jeremy, J Y

2008-11-01

To determine whether there is an association between vascular NADPH oxidase (NOX), superoxide, the small GTPase Rac(1) and PDE type 5 (PDE5) in human vascular smooth muscle cell (hVSMCs). hVSMCs were incubated with xanthine-xanthine oxidase (X-XO; a superoxide generating system) or the thromboxane A(2) analogue, U46619 (+/-superoxide dismutase (SOD) or apocynin) for 16 h. The expression of PDE5 and NOX-1 was assessed using Western blotting and superoxide measured. The role of Rac(1) in superoxide generation was assessed by overexpressing either the dominant-negative or constitutively active Rac isoforms. The effects of iloprost, DETA-NONOate and the Rho-kinase inhibitor, Y27632, on PDE5 and NOX-1 expression were also studied. Following 16 h incubation, U46619 and X-XO promoted the expression of PDE5 and NOX-1, an effect blocked by SOD or apocynin when co-incubated over the same time course. X-XO and U46619 both promoted the formation of superoxide. Overexpression of dominant-negative Rac(1) or addition of iloprost, DETA-NONOate or Y27632 completely blocked both superoxide release and PDE5 protein expression and activity. These data demonstrate that superoxide derived from NOX upregulates the expression of PDE5 in human VSMCs. As PDE5 hydrolyses cyclic GMP, this effect may blunt the vasculoprotective actions of NO.
Rac1 Is Required for Cardiomyocyte Apoptosis During Hyperglycemia

PubMed Central

Shen, E.; Li, Yanwen; Li, Ying; Shan, Limei; Zhu, Huaqing; Feng, Qingping; Arnold, J. Malcolm O.; Peng, Tianqing

2009-01-01

OBJECTIVE Hyperglycemia induces reactive oxygen species (ROS) and apoptosis in cardiomyocytes, which contributes to diabetic cardiomyopathy. The present study was to investigate the role of Rac1 in ROS production and cardiomyocyte apoptosis during hyperglycemia. RESEARCH DESIGN AND METHODS Mice with cardiomyocyte-specific Rac1 knockout (Rac1-ko) were generated. Hyperglycemia was induced in Rac1-ko mice and their wild-type littermates by injection of streptozotocin (STZ). In cultured adult rat cardiomyocytes, apoptosis was induced by high glucose. RESULTS The results showed a mouse model of STZ-induced diabetes, 7 days of hyperglycemia-upregulated Rac1 and NADPH oxidase activation, elevated ROS production, and induced apoptosis in the heart. These effects of hyperglycemia were significantly decreased in Rac1-ko mice or wild-type mice treated with apocynin. Interestingly, deficiency of Rac1 or apocynin treatment significantly reduced hyperglycemia-induced mitochondrial ROS production in the heart. Deficiency of Rac1 also attenuated myocardial dysfunction after 2 months of STZ injection. In cultured cardiomyocytes, high glucose upregulated Rac1 and NADPH oxidase activity and induced apoptotic cell death, which were blocked by overexpression of a dominant negative mutant of Rac1, knockdown of gp91phox or p47phox, or NADPH oxidase inhibitor. In type 2 diabetic db/db mice, administration of Rac1 inhibitor, NSC23766, significantly inhibited NADPH oxidase activity and apoptosis and slightly improved myocardial function. CONCLUSIONS Rac1 is pivotal in hyperglycemia-induced apoptosis in cardiomyocytes. The role of Rac1 is mediated through NADPH oxidase activation and associated with mitochondrial ROS generation. Our study suggests that Rac1 may serve as a potential therapeutic target for cardiac complications of diabetes. PMID:19592621
Dosage-dependent role of Rac1 in podocyte injury.

PubMed

Wan, Xiaoyang; Lee, Mi-Sun; Zhou, Weibin

2016-04-15

Activation of small GTPase Rac1 in podocytes is associated with rodent models of kidney injury and familial nephrotic syndrome. Induced Rac1 activation in podocytes in transgenic mice results in rapid transient proteinuria and foot process effacement, but not glomerular sclerosis. Thus it remains an open question whether abnormal activation of Rac1 in podocytes is sufficient to cause permanent podocyte damage. Using a number of transgenic zebrafish models, we showed that moderate elevation of Rac1 activity in podocytes did not impair the glomerular filtration barrier but aggravated metronidazole-induced podocyte injury, while inhibition of Rac1 activity ameliorated metronidazole-induced podocyte injury. Furthermore, a further increase in Rac1 activity in podocytes was sufficient to cause proteinuria and foot process effacement, which resulted in edema and lethality in juvenile zebrafish. We also found that activation of Rac1 in podocytes significantly downregulated the expression of nephrin and podocin , suggesting an adverse effect of Rac1 on slit diaphragm protein expression. Taken together, our data have demonstrated a causal link between excessive Rac1 activity and podocyte injury in a dosage-dependent manner, and transgenic zebrafish of variable Rac1 activities in podocytes may serve as useful animal models for the study of Rac1-related podocytopathy. Copyright © 2016 the American Physiological Society.
Small G protein Rac GTPases regulate the maintenance of glioblastoma stem-like cells in vitro and in vivo.

PubMed

Lai, Yun-Ju; Tsai, Jui-Cheng; Tseng, Ying-Ting; Wu, Meng-Shih; Liu, Wen-Shan; Lam, Hoi-Ian; Yu, Jei-Hwa; Nozell, Susan E; Benveniste, Etty N

2017-03-14

Glioblastoma is the most common and aggressive malignant brain tumor in adults. The existence of glioblastoma stem cells (GSCs) or stem-like cells (stemloids) may account for its invasiveness and high recurrence. Rac proteins belong to the Rho small GTPase subfamily which regulates cell movement, proliferation, and survival. To investigate whether Rac proteins can serve as therapeutic targets for glioblastoma, especially for GSCs or stemloids, we examined the potential roles of Rac1, Rac2 and Rac3 on the properties of tumorspheres derived from glioblastoma cell lines. Tumorspheres are thought to be glioblastoma stem-like cells. We showed that Rac proteins promote the STAT3 and ERK activation and enhance cell proliferation and colony formation of glioblastoma stem-like cells. Knockdown of Rac proteins reduces the expression of GSC markers, such as CD133 and Sox2. The in vivo effects of Rac proteins in glioblastoma were further studied in zebrafish and in the mouse xenotransplantation model. Knocking-down Rac proteins abolished the angiogenesis effect induced by the injected tumorspheres in zebrafish model. In the CD133+-U373-tumorsphere xenotransplanted mouse model, suppression of Rac proteins decreased the incidence of tumor formation and inhibited the tumor growth. Moreover, knockdown of Rac proteins reduced the sphere forming efficiency of cells derived from these tumors. In conclusion, not only Rac1 but also Rac2 and 3 are important for glioblastoma tumorigenesis and can serve as the potential therapeutic targets against glioblastoma and its stem-like cells.
Small G protein Rac GTPases regulate the maintenance of glioblastoma stem-like cells in vitro and in vivo

PubMed Central

Lai, Yun-Ju; Tsai, Jui-Cheng; Tseng, Ying-Ting; Wu, Meng-Shih; Liu, Wen-Shan; Lam, Hoi-Ian; Yu, Jei-Hwa; Nozell, Susan E.; Benveniste, Etty N.

2017-01-01

Glioblastoma is the most common and aggressive malignant brain tumor in adults. The existence of glioblastoma stem cells (GSCs) or stem–like cells (stemloids) may account for its invasiveness and high recurrence. Rac proteins belong to the Rho small GTPase subfamily which regulates cell movement, proliferation, and survival. To investigate whether Rac proteins can serve as therapeutic targets for glioblastoma, especially for GSCs or stemloids, we examined the potential roles of Rac1, Rac2 and Rac3 on the properties of tumorspheres derived from glioblastoma cell lines. Tumorspheres are thought to be glioblastoma stem-like cells. We showed that Rac proteins promote the STAT3 and ERK activation and enhance cell proliferation and colony formation of glioblastoma stem-like cells. Knockdown of Rac proteins reduces the expression of GSC markers, such as CD133 and Sox2. The in vivo effects of Rac proteins in glioblastoma were further studied in zebrafish and in the mouse xenotransplantation model. Knocking-down Rac proteins abolished the angiogenesis effect induced by the injected tumorspheres in zebrafish model. In the CD133+-U373-tumorsphere xenotransplanted mouse model, suppression of Rac proteins decreased the incidence of tumor formation and inhibited the tumor growth. Moreover, knockdown of Rac proteins reduced the sphere forming efficiency of cells derived from these tumors. In conclusion, not only Rac1 but also Rac2 and 3 are important for glioblastoma tumorigenesis and can serve as the potential therapeutic targets against glioblastoma and its stem-like cells. PMID:28160553

The effects of increasing supplementation of zinc-amino acid complex on growth performance, carcass characteristics, and inflammatory response of beef cattle fed ractopamine hydrochloride.

PubMed

Genther-Schroeder, O N; Branine, M E; Hansen, S L

2016-08-01

Forty-two Angus crossbred steers (380 ± 5.3 kg) were enrolled in a finishing study to evaluate the influence of a supplemental Zn amino-acid complex (ZnAA; Availa-Zn) on performance and carcass characteristics of finishing steers in combination with ractopamine hydrochloride (RAC). Steers were stratified by BW into 7 pens of 6 steers each, and individual feed intake was measured. Steers were assigned to 1 of 4 treatments for 86 d (pre-RAC period): a dry-rolled corn-based diet supplemented with 60 mg Zn/kg DM from ZnSO and no supplemental ZnAA (CON; analyzed 88 mg Zn/kg DM; = 6) or CON diet supplemented with 30 (Zn30; = 12), 60 (Zn60; = 12), or 90 (Zn90; = 11) mg Zn/kg DM from ZnAA. Day 86 BW and G:F displayed a quadratic tendency ( = 0.09) with Zn60 steers being greater than the other treatments. Plasma cyclic adenosine monophosphate tended to linearly increase with increasing ZnAA ( = 0.10). On d 88, 6 of 12 steers (one of the 2 pens) receiving supplemental ZnAA was randomly selected to be supplemented with RAC at 300 mg∙steer∙d for the final 28 d of the experiment (RAC period). This created 7 final treatments: CON: no supplemental ZnAA, no RAC ( = 5); Zn30: Zn30, no RAC ( = 5); Zn30R: Zn30 + RAC ( = 6); Zn60: Zn60, no RAC ( = 6); Zn60R: Zn60 + RAC ( = 6); Zn90: Zn90, no RAC ( = 5); and Zn90R: Zn90 + RAC ( = 6). During the RAC period, as supplemental ZnAA increased within RAC-supplemented treatments, there was a linear increase in final BW, ADG, and G:F ( < 0.05). However, there was no effect of supplemental ZnAA on BW, ADG, or G:F during this period in non-RAC fed steers ( ≥ 0.44). Day 111 plasma Cu was increased, plasma Fe decreased, and leukocyte counts and serum interleukin-8 concentrations were greater ( < 0.05) in RAC-fed steers suggesting that RAC may elicit a mild inflammatory response. There was a tendency for increasing Zn supplementation to decrease plasma haptoglobin within RAC-fed steers ( = 0.07), suggesting that Zn may alter the inflammatory response. Overall, Zn60 improved growth performance during the pre-RAC period. Zinc supplemented as ZnAA appears to improve growth in combination with RAC supplementation, suggesting that Zn may enhance or support the biological function of RAC. Additionally, these results indicate that feeding RAC impacts trace mineral status, and potentially causes a non-specific inflammatory response, but further research is required to define this response.
Inhibition of the Rac1-WAVE2-Arp2/3 signaling pathway promotes radiosensitivity via downregulation of cofilin-1 in U251 human glioma cells.

PubMed

Zhou, Tao; Wang, Chen-Han; Yan, Hua; Zhang, Rui; Zhao, Jin-Bing; Qian, Chun-Fa; Xiao, Hong; Liu, Hong-Yi

2016-05-01

The Ras-related C3 botulinum toxin substrate 1 (Rac1)-WASP-family verprolin-homologous protein-2 (WAVE2)-actin-related protein 2/3 (Arp2/3) signaling pathway has been identified to be involved in cell migration and invasion in various types of cancer cell. Cofilin‑1 (CFL‑1), which is regulated by the Rac1‑WAVE2‑Arp2/3 signaling pathway, may promote radioresistance in glioma. Therefore, the present study aimed to investigate the potential role of the Rac1‑WAVE2‑Arp2/3 signaling pathway in radioresistance in U251 human glioma cells and elucidate its affect on CFL‑1 expression. Western blot analysis was performed to evaluate the protein expression of CFL‑1. In the present study, Rac1 was inhibited by NSC 23766, WAVE2 was inhibited by transfection with short hairpin (sh)RNA‑WAVE2 using Lipofectamine™ 2000 and Arp2/3 was inhibited by CK‑666. Cell viability was measured using the 3‑(4,5‑dimethylthiazol‑2‑yl)-2,5‑diphenyltetrazolium bromide assay, the cell migration ability was examined by a wound‑healing assay, and the cell invasion ability was assessed using a Transwell culture chamber system. The results showed that inhibition of the Rac1‑WAVE2‑Arp2/3 signaling pathway using NSC 23766, shRNA‑WAVE2 or CK‑666 reduced the cell viability, migration and invasion abilities in U251 human glioma cells, concordant with a reduced expression of CFL‑1. Furthermore, the expression of CFL‑1 was significantly increased in radioresistant U251 glioma cells when compared with normal U251 human glioma cells. These findings indicate that inhibition of the Rac1‑WAVE2‑Arp2/3 signaling pathway may promote radiosensitivity, which may partially result from the downregulation of CFL‑1 in U251 human glioma cells.
Rac3 Regulates Cell Invasion, Migration and EMT in Lung Adenocarcinoma through p38 MAPK Pathway

PubMed Central

Zhang, Chenlei; Liu, Tieqin; Wang, Gebang; Wang, Huan; Che, Xiaofang; Gao, Xinghua; Liu, Hongxu

2017-01-01

Background: The role of Rac3 in cell proliferation in lung adenocarcinoma has been tackled in our previous study. However, the role of Rac3 in cell invasion and migration of lung adenocarcinoma is still not clear. Methods: The expression of Rac3 in lung adenocarcinoma specimens and paired noncancerous normal tissues were evaluated by immunohistochemistry. Lentivirus-mediated RNA interference (RNAi) was employed to silence Rac3 in lung adenocarcinoma cell lines A549 and H1299. A p38 MAPK inhibitor (LY2228820) was employed to inhibit activity of p38 MAPK pathway. Cell invasion and migration in vitro were examined by invasion and migration assays, respectively. PathScan® intracellular signaling array kit and western blot were employed in mechanism investigation. Results: Rac3 expression was frequently higher in lung adenocarcinoma than paired noncancerous normal tissues. Rac3 expression was an independent risk factor for lymphonode metastasis, and was associated with worse survival outcome. Silencing of Rac3 inhibited cell invasion and cell migration in lung adenocarcinoma cell lines. Knockdown of Rac3 decreased activity of p38 MAPK pathway. LY2228820, which was an important p38 MAPK inhibitor, inhibited Rac3-induced cell invasion and migration of lung adenocarcinoma. E-cadherin expression was increased and vimentin expression was decreased after silencing of Rac3 or following the treatment of LY2228820. Conclusions: Our findings suggest that Rac3 regulates cell invasion, migration and EMT via p38 MAPK pathway. Rac3 may be a potential biomarker of invasion and metastasis for lung adenocarcinoma, and knockdown of Rac3 may potentially serve as a promising therapeutic target for lung adenocarcinoma. PMID:28900489
Rac1b enhances cell survival through activation of the JNK2/c-JUN/Cyclin-D1 and AKT2/MCL1 pathways

PubMed Central

Wang, Hong; Wei, Si-Si; Chen, Jie; Chen, Yi-He; Xu, Wei-Ping; Jie, Qi-Qiang; Zhou, Qing; Li, Yi-Gang; Wei, Yi-Dong; Wang, Yue-Peng

2016-01-01

Rac1b is a constitutively activated, alternatively spliced form of the small GTPase Rac1. Previous studies showed that Rac1b promotes cell proliferation and inhibits apoptosis. In the present study, we used microarray analysis to detect genes differentially expressed in HEK293T cells and SW480 human colon cancer cells stably overexpressing Rac1b. We found that the pro-proliferation genes JNK2, c-JUN and cyclin-D1 as well as anti-apoptotic AKT2 and MCL1 were all upregulated in both lines. Rac1b promoted cell proliferation and inhibited apoptosis by activating the JNK2/c-JUN/cyclin-D1 and AKT2/MCL1 pathways, respectively. Very low Rac1b levels were detected in the colonic epithelium of wild-type Sprague-Dawley rats. Knockout of the rat Rac1 gene exon-3b or knockdown of endogenous Rac1b in HT29 human colon cancer cells downregulated only the AKT2/MCL1 pathway. Our study revealed that very low levels of endogenous Rac1b inhibit apoptosis, while Rac1b upregulation both promotes cell proliferation and inhibits apoptosis. It is likely the AKT2/MCL1 pathway is more sensitive to Rac1b regulation. PMID:26918455
Interactions of UNC-34 Enabled With Rac GTPases and the NIK Kinase MIG-15 in Caenorhabditis elegans Axon Pathfinding and Neuronal Migration

PubMed Central

Shakir, M. Afaq; Gill, Jason S.; Lundquist, Erik A.

2006-01-01

Many genes that affect axon pathfinding and cell migration have been identified. Mechanisms by which these genes and the molecules they encode interact with one another in pathways and networks to control developmental events are unclear. Rac GTPases, the cytoskeletal signaling molecule Enabled, and NIK kinase have all been implicated in regulating axon pathfinding and cell migration. Here we present evidence that, in Caenorhabditis elegans, three Rac GTPases, CED-10, RAC-2, and MIG-2, define three redundant pathways that each control axon pathfinding, and that the NIK kinase MIG-15 acts in each Rac pathway. Furthermore, we show that the Enabled molecule UNC-34 defines a fourth partially redundant pathway that acts in parallel to Rac/MIG-15 signaling in axon pathfinding. Enabled and the three Racs also act redundantly to mediate AQR and PQR neuronal cell migration. The Racs and UNC-34 Ena might all control the formation of actin-based protrusive structures (lamellipodia and filopodia) that mediate growth cone outgrowth and cell migration. MIG-15 does not act with the three Racs in execution of cell migration. Rather, MIG-15 affects direction of PQR neuronal migration, similar to UNC-40 and DPY-19, which control initial Q cell polarity, and Wnt signaling, which acts later to control Q cell-directed migration. MIG-2 Rac, which acts with CED-10 Rac, RAC-2 Rac, and UNC-34 Ena in axon pathfinding and cell migration, also acts with MIG-15 in PQR directional migration. PMID:16204220
Fractionation of trace elements in agricultural soils using ultrasound assisted sequential extraction prior to inductively coupled plasma mass spectrometric determination.

PubMed

Matong, Joseph M; Nyaba, Luthando; Nomngongo, Philiswa N

2016-07-01

The main objectives of this study were to determine the concentration of fourteen trace elements and to investigate their distribution as well as a contamination levels in selected agricultural soils. An ultrasonic assisted sequential extraction procedure derived from three-step BCR method was used for fractionation of trace elements. The total concentration of trace elements in soil samples was obtained by total digestion method in soil samples with aqua regia. The results of the extractable fractions revealed that most of the target trace elements can be transferred to the human being through the food chain, thus leading to serious human health. Enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), risk assessment code (RAC) and individual contamination factors (ICF) were used to assess the environmental impacts of trace metals in soil samples. The EF revealed that Cd was enriched by 3.1-7.2 (except in Soil 1). The Igeo results showed that the soils in the study area was moderately contaminated with Fe, and heavily to extremely polluted with Cd. The soil samples from the unplanted field was found to have highest contamination factor for Cd and lowest for Pb. Soil 3 showed a high risk for Tl and Cd with RAC values of greater than or equal to 50%. In addition, Fe, Ni, Cu, V, As, Mo (except Soil 2), Sb and Pb posed low environmental risk. The modified BCR sequential extraction method provided more information about mobility and environmental implication of studied trace elements in the study area. Copyright © 2016 Elsevier Ltd. All rights reserved.
Chronic aquatic effect assessment for the fungicide azoxystrobin.

PubMed

van Wijngaarden, Rene P A; Belgers, Dick J M; Zafar, Mazhar I; Matser, Arrienne M; Boerwinkel, Marie-Claire; Arts, Gertie H P

2014-12-01

The present study examined the ecological effects of a range of chronic exposure concentrations of the fungicide azoxystrobin in freshwater experimental systems (1270-L outdoor microcosms). Intended and environmentally relevant test concentrations of azoxystrobin were 0 µg active ingredient (a.i.)/L, 0.33 µg a.i./L, 1 µg a.i./L, 3.3 µg a.i./L, 10 µg a.i./L, and 33 µg a.i./L, kept at constant values. Responses of freshwater populations and community parameters were studied. During the 42-d experimental period, the time-weighted average concentrations of azoxystrobin ranged from 93.5% to 99.3% of intended values. Zooplankton, especially copepods and the Daphnia longispina group, were the most sensitive groups. At the population level, a consistent no-observed-effect concentration (NOEC) of 1 µg a.i./L was calculated for Copepoda. The NOEC at the zooplankton community level was 10 µg azoxystrobin/L. The principle of the European Union pesticide directive is that lower-tier regulatory acceptable concentrations (RACs) are protective of higher-tier RACs. This was tested for chronic risks from azoxystrobin. With the exception of the microcosm community chronic RAC (highest tier), all other chronic RAC values were similar to each other (0.5-1 µg a.i./L). The new and stricter first-tier species requirements of the European Union pesticide regulation (1107/2009/EC) are not protective for the most sensitive populations in the microcosm study, when based on the higher tier population RAC. In comparison, the Water Framework Directive generates environmental quality standards that are 5 to 10 times lower than the derived chronic RACs. © 2014 SETAC.
Overexpression of Rac1 in leukemia patients and its role in leukemia cell migration and growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jiying; Rao, Qing, E-mail: raoqing@gmail.com; Wang, Min

2009-09-04

Rac1 belongs to the Rho family that act as critical mediators of signaling pathways controlling cell migration and proliferation and contributes to the interactions of hematopoietic stem cells with their microenvironment. Alteration of Rac1 might result in unbalanced interactions and ultimately lead to leukemogenesis. In this study, we analyze the expression of Rac1 protein in leukemia patients and determine its role in the abnormal behaviours of leukemic cells. Rac1 protein is overexpressed in primary acute myeloid leukemia cells as compared to normal bone marrow mononuclear cells. siRNA-mediated silencing of Rac1 in leukemia cell lines induced inhibition of cell migration, proliferation,more » and colony formation. Additionally, blocking Rac1 activity by an inhibitor of Rac1-GTPase, NSC23766, suppressed cell migration and growth. We conclude that overexpression of Rac1 contributes to the accelerated migration and high proliferation potential of leukemia cells, which could be implicated in leukemia development and progression.« less
WAVE2 serves a functional partner of IRSp53 by regulating its interaction with Rac.

PubMed

Miki, Hiroaki; Takenawa, Tadaomi

2002-04-26

We previously reported that IRSp53 binds both Rac and WAVE2, inducing formation of Rac/IRSp53/WAVE2 complex that is important for membrane ruffling. However, recent reports noted a specific interaction between IRSp53 and Cdc42 but not Rac, which led us to re-examine the binding of IRSp53 to Rac. Immunoprecipitation analysis and pull-down assay reveal that full-length IRSp53 binds Rac much less efficiently than the N-terminal fragment, which may be caused by intramolecular interaction. Interestingly, the intramolecular interaction is interrupted by the binding of WAVE2 and full-length IRSp53 associates with Rac in the presence of WAVE2. We also report that IRSp53 induces spreading and neurite formation of N1E-115 cells, which presumably reflect functional cooperation with Rac.
Distribution, Fraction, and Ecological Assessment of Heavy Metals in Sediment-Plant System in Mangrove Forest, South China Sea.

PubMed

Li, Ruili; Chai, Minwei; Qiu, Guo Yu

2016-01-01

Overlying water, sediment, rhizosphere sediment and mangrove seedlings in the Futian mangrove forest were analyzed for heavy metals. The results showed that mangrove plant acidified sediment and increased organic matter contents. Except for chromium (Cr), nickel (Ni) and copper (Cu) in Aegiceras corniculatum sediment, heavy metals in all sediments were higher than in overlying water, rhizosphere sediment and mangrove root. Heavy metals in Avicennia marina sediments were higher than other sediments. The lower heavy metal biological concentration factors (BCFs) and translocation factors (TFs) indicated that mangrove plant adopted exclusion strategy. The geo-accumulation index, potential ecological risk index and risk assessment code (RAC) demonstrated that heavy metals have posed a considerable ecological risk, especially for cadmium (Cd). Heavy metals (Cr, Ni, Cu and Cd) mainly existed in the reducible fractions. These findings provide actual heavy metal accumulations in sediment-plant ecosystems in mangrove forest, being important in designing the long-term management and conservation policies for managers of mangrove forest.
Distribution, Fraction, and Ecological Assessment of Heavy Metals in Sediment-Plant System in Mangrove Forest, South China Sea

PubMed Central

Li, Ruili; Chai, Minwei; Qiu, Guo Yu

2016-01-01

Overlying water, sediment, rhizosphere sediment and mangrove seedlings in the Futian mangrove forest were analyzed for heavy metals. The results showed that mangrove plant acidified sediment and increased organic matter contents. Except for chromium (Cr), nickel (Ni) and copper (Cu) in Aegiceras corniculatum sediment, heavy metals in all sediments were higher than in overlying water, rhizosphere sediment and mangrove root. Heavy metals in Avicennia marina sediments were higher than other sediments. The lower heavy metal biological concentration factors (BCFs) and translocation factors (TFs) indicated that mangrove plant adopted exclusion strategy. The geo-accumulation index, potential ecological risk index and risk assessment code (RAC) demonstrated that heavy metals have posed a considerable ecological risk, especially for cadmium (Cd). Heavy metals (Cr, Ni, Cu and Cd) mainly existed in the reducible fractions. These findings provide actual heavy metal accumulations in sediment-plant ecosystems in mangrove forest, being important in designing the long-term management and conservation policies for managers of mangrove forest. PMID:26800267
Expression of Ras-related C3 botulinum toxin substrate 1 (RAC1) in human cholesteatoma.

PubMed

Lee, No Hee; Chang, Ji-Won; Choi, June; Jung, Hak Hyun; Im, Gi Jung

2013-02-01

Ras-related C3 botulinum toxin substrate 1 (RAC1) is a 21-kDa signaling G protein that functions as a pleiotropic regulator of many cellular processes including epithelial differentiation. RAC1 activates the nicotinamide adenine dinucleotide phosphate oxidase complex which promotes formation of reactive oxygen species and degradation enzymes. RAC1 has been associated with rapid epithelial differentiation and invasive properties in human cholesteatoma. This study aimed to identify the presence of RAC1 in human cholesteatoma and analyze its functional role as a regulator of proteolysis and overgrowth. Tissue samples from human cholesteatoma and normal postaural skin were obtained from patients during otologic surgery for cholesteatoma. The expression of RAC1 mRNA was quantified by real-time RT-PCR, and localization of RAC1 expression was confirmed using immunohistochemical staining. Expression of RAC1 mRNA in the epithelium of cholesteatoma was significantly elevated 2.94 fold on average, compared with normal control skin. RAC1 expression in the suprabasal and basal layer of cholesteatoma epithelium was stronger than normal control skin. Our results suggest that RAC1 can be associated with rapid epithelial differentiation and invasive properties of human cholesteatoma.
Comparative environmental assessment of natural and recycled aggregate concrete.

PubMed

Marinković, S; Radonjanin, V; Malešev, M; Ignjatović, I

2010-11-01

Constant and rapid increase in construction and demolition (C&D) waste generation and consumption of natural aggregate for concrete production became one of the biggest environmental problems in the construction industry. Recycling of C&D waste represents one way to convert a waste product into a resource but the environment benefits through energy consumption, emissions and fallouts reductions are not certain. The main purpose of this study is to determine the potentials of recycled aggregate concrete (concrete made with recycled concrete aggregate) for structural applications and to compare the environmental impact of the production of two types of ready-mixed concrete: natural aggregate concrete (NAC) made entirely with river aggregate and recycled aggregate concrete (RAC) made with natural fine and recycled coarse aggregate. Based on the analysis of up-to-date experimental evidence, including own tests results, it is concluded that utilization of RAC for low-to-middle strength structural concrete and non-aggressive exposure conditions is technically feasible. The Life Cycle Assessment (LCA) is performed for raw material extraction and material production part of the concrete life cycle including transport. Assessment is based on local LCI data and on typical conditions in Serbia. Results of this specific case study show that impacts of aggregate and cement production phases are slightly larger for RAC than for NAC but the total environmental impacts depend on the natural and recycled aggregates transport distances and on transport types. Limit natural aggregate transport distances above which the environmental impacts of RAC can be equal or even lower than the impacts of NAC are calculated for the specific case study. Copyright © 2010 Elsevier Ltd. All rights reserved.
Activated Rac1 requires gp130 for Stat3 activation, cell proliferation and migration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arulanandam, Rozanne; Geletu, Mulu; Feracci, Helene

2010-03-10

Rac1 (Rac) is a member of the Rho family of small GTPases which controls cell migration by regulating the organization of actin filaments. Previous results suggested that mutationally activated forms of the Rho GTPases can activate the Signal Transducer and Activator of Transcription-3 (Stat3), but the exact mechanism is a matter of controversy. We recently demonstrated that Stat3 activity of cultured cells increases dramatically following E-cadherin engagement. To better understand this pathway, we now compared Stat3 activity levels in mouse HC11 cells before and after expression of the mutationally activated Rac1 (Rac{sup V12}), at different cell densities. The results revealedmore » for the first time a dramatic increase in protein levels and activity of both the endogenous Rac and Rac{sup V12} with cell density, which was due to inhibition of proteasomal degradation. In addition, Rac{sup V12}-expressing cells had higher Stat3, tyrosine-705 phosphorylation and activity levels at all densities, indicating that Rac{sup V12} is able to activate Stat3. Further examination of the mechanism of Stat3 activation showed that Rac{sup V12} expression caused a surge in mRNA of Interleukin-6 (IL6) family cytokines, known potent Stat3 activators. Knockdown of gp130, the common subunit of this family reduced Stat3 activity, indicating that these cytokines may be responsible for the Stat3 activation by Rac{sup V12}. The upregulation of IL6 family cytokines was required for cell migration and proliferation induced by Rac{sup V12}, as shown by gp130 knockdown experiments, thus demonstrating that the gp130/Stat3 axis represents an essential effector of activated Rac for the regulation of key cellular functions.« less
Rac1 as a potential therapeutic target for chemo-radioresistant head and neck squamous cell carcinomas (HNSCC).

PubMed

Skvortsov, S; Dudás, J; Eichberger, P; Witsch-Baumgartner, M; Loeffler-Ragg, J; Pritz, C; Schartinger, V H; Maier, H; Hall, J; Debbage, P; Riechelmann, H; Lukas, P; Skvortsova, I

2014-05-27

In order to improve therapy for HNSCC patients, novel methods to predict and combat local and/or distant tumour relapses are urgently needed. This study has been dedicated to the hypothesis that Rac1, a Rho GTPase, is implicated in HNSCC insensitivity to chemo-radiotherapy resulting in tumour recurrence development. Parental and radiation-resistant (IRR) HNSCC cells were used to support this hypothesis. All cells were investigated for their sensitivity to ionising radiation and cisplatin, Rac1 activity, its intracellular expression and subcellular localisation. Additionally, tumour tissues obtained from 60 HNSCC patients showing different therapy response were evaluated for intratumoral Rac1 expression. Radiation-resistant IRR cells also revealed resistance to cisplatin accompanied by increased expression, activity and trend towards nuclear translocation of Rac1 protein. Chemical inhibition of Rac1 expression and activity resulted in significant improvement of HNSCC sensitivity to ionising radiation and cisplatin. Preclinical results were confirmed in clinical samples. Although Rac1 was poorly presented in normal mucosa, tumour tissues revealed increased Rac1 expression. The most pronounced Rac1 presence was observed in HNSCC patients with poor early or late responses to chemo-radiotherapy. Tissues taken at recurrence were characterised not only by enhanced Rac1 expression but also increased nuclear Rac1 content. Increased expression, activity and subcellular localisation of Rac1 could be associated with lower early response rate and higher risk of tumour recurrences in HNSCC patients and warrants further validation in larger independent studies. Inhibition of Rac1 activity can be useful in overcoming treatment resistance and could be proposed for HNSCC patients with primary or secondary chemo-radioresistance.
Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate

PubMed Central

Muzaffar, S; Shukla, N; Bond, M; Sala-Newby, G B; Newby, A C; Angelini, G D; Jeremy, J Y

2008-01-01

Background and purpose: To determine whether there is an association between vascular NADPH oxidase (NOX), superoxide, the small GTPase Rac1 and PDE type 5 (PDE5) in human vascular smooth muscle cell (hVSMCs). Experimental approach: hVSMCs were incubated with xanthine–xanthine oxidase (X-XO; a superoxide generating system) or the thromboxane A2 analogue, U46619 (±superoxide dismutase (SOD) or apocynin) for 16 h. The expression of PDE5 and NOX-1 was assessed using Western blotting and superoxide measured. The role of Rac1 in superoxide generation was assessed by overexpressing either the dominant-negative or constitutively active Rac isoforms. The effects of iloprost, DETA-NONOate and the Rho-kinase inhibitor, Y27632, on PDE5 and NOX-1 expression were also studied. Key results: Following 16 h incubation, U46619 and X-XO promoted the expression of PDE5 and NOX-1, an effect blocked by SOD or apocynin when co-incubated over the same time course. X-XO and U46619 both promoted the formation of superoxide. Overexpression of dominant-negative Rac1 or addition of iloprost, DETA-NONOate or Y27632 completely blocked both superoxide release and PDE5 protein expression and activity. Conclusions and implications: These data demonstrate that superoxide derived from NOX upregulates the expression of PDE5 in human VSMCs. As PDE5 hydrolyses cyclic GMP, this effect may blunt the vasculoprotective actions of NO. PMID:18660830
Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis

PubMed Central

Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

2017-01-01

Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways. PMID:28277539
Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis.

PubMed

Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

2017-03-09

Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways.
RAC1b overexpression stimulates proliferation and NF-kB-mediated anti-apoptotic signaling in thyroid cancer cells

PubMed Central

Faria, Márcia; Matos, Paulo; Pereira, Teresa; Cabrera, Rafael; Cardoso, Bruno A.; Bugalho, Maria João

2017-01-01

Overexpression of tumor-associated RAC1b has been recently highlighted as one of the most promising targets for therapeutic intervention in colon, breast, lung and pancreatic cancer. RAC1b is a hyperactive variant of the small GTPase RAC1 and has been recently shown to be overexpressed in a subset of papillary thyroid carcinomas associated with unfavorable outcome. Using the K1 PTC derived cell line as an in vitro model, we observed that both RAC1 and RAC1b were able to induce a significant increase on NF-kB and cyclin D1 reporter activity. A clear p65 nuclear localization was found in cells transfected with RAC1b-WT, confirming NF-kB canonical pathway activation. Consistently, we observed a RAC1b-mediated decrease in IκBα (NF-kB inhibitor) protein levels. Moreover, we show that RAC1b overexpression stimulates G1/S progression and protects thyroid cells against induced apoptosis, the latter through a process involving the NF-kB pathway. Present data support previous findings suggesting an important role for RAC1b in the development of follicular cell-derived thyroid malignancies and point out NF-kB activation as one of the molecular mechanisms associated with the pro-tumorigenic advantage of RAC1b overexpression in thyroid carcinomas. PMID:28234980
Inhibition of Rac1 Activity in the Hippocampus Impairs the Forgetting of Contextual Fear Memory.

PubMed

Jiang, Lizhu; Mao, Rongrong; Zhou, Qixin; Yang, Yuexiong; Cao, Jun; Ding, Yuqiang; Yang, Yuan; Zhang, Xia; Li, Lingjiang; Xu, Lin

2016-03-01

Fear is crucial for survival, whereas hypermnesia of fear can be detrimental. Inhibition of the Rac GTPase is recently reported to impair the forgetting of initially acquired memory in Drosophila. Here, we investigated whether inhibition of Rac1 activity in rat hippocampus could contribute to the hypermnesia of contextual fear. We found that spaced but not massed training of contextual fear conditioning caused inhibition of Rac1 activity in the hippocampus and heightened contextual fear. Furthermore, intrahippocampal injection of the Rac1 inhibitor NSC23766 heightened contextual fear in massed training, while Rac1 activator CN04-A weakened contextual fear in spaced training rats. Our study firstly demonstrates that contextual fear memory in rats is actively regulated by Rac1 activity in the hippocampus, which suggests that the forgetting impairment of traumatic events in posttraumatic stress disorder may be contributed to the pathological inhibition of Rac1 activity in the hippocampus.

The RAC program: what can radiology providers expect as RACs begin auditing?

PubMed

Pendleton, Abby; Gustafson, Jessica L

2009-01-01

The Centers for Medicare and Medicaid Services (CMS) Recovery Audit Contractor (RAC) program has been made permanent and is expanding nationwide. Radiology providers should be ready for increased Medicare auditing activity as the RAC expands. Should a provider or supplier be subject to a RAC audit, effective strategies are available that can be successfully employed in the appeals process to challenge denials.
Dissociation of Rac1(GDP)·RhoGDI Complexes by the Cooperative Action of Anionic Liposomes Containing Phosphatidylinositol 3,4,5-Trisphosphate, Rac Guanine Nucleotide Exchange Factor, and GTP*

PubMed Central

Ugolev, Yelena; Berdichevsky, Yevgeny; Weinbaum, Carolyn; Pick, Edgar

2008-01-01

Rac plays a pivotal role in the assembly of the superoxide-generating NADPH oxidase of phagocytes. In resting cells, Rac is found in the cytosol in complex with Rho GDP dissociation inhibitor (RhoGDI). NADPH oxidase assembly involves dissociation of the Rac·RhoGDI complex and translocation of Rac to the membrane. We reported that liposomes containing high concentrations of monovalent anionic phospholipids cause Rac·RhoGDI complex dissociation (Ugolev, Y., Molshanski-Mor, S., Weinbaum, C., and Pick, E. (2006) J. Biol. Chem.281 ,19204 -1921916702219). We now designed an in vitro model mimicking membrane phospholipid remodeling during phagocyte stimulation in vivo. We showed that liposomes of “resting cell membrane” composition (less than 20 mol % monovalent anionic phospholipids), supplemented with 1 mol % of polyvalent anionic phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) in conjunction with constitutively active forms of the guanine nucleotide exchange factors (GEFs) for Rac, Trio, or Tiam1 and a non-hydrolyzable GTP analogue, cause dissociation of Rac1(GDP)·RhoGDI complexes, GDP to GTP exchange on Rac1, and binding of Rac1(GTP) to the liposomes. Complexes were not dissociated in the absence of GEF and GTP, and optimal dissociation required the presence of PtdIns(3,4,5)P3 in the liposomes. Dissociation of Rac1(GDP)·RhoGDI complexes was correlated with the affinity of particular GEF constructs, via the N-terminal pleckstrin homology domain, for PtdIns(3,4,5)P3 and involved GEF-mediated GDP to GTP exchange on Rac1. Phagocyte membranes enriched in PtdIns(3,4,5)P3 responded by NADPH oxidase activation upon exposure in vitro to Rac1(GDP)·RhoGDI complexes, p67phox, GTP, and Rac GEF constructs with affinity for PtdIns(3,4,5)P3 at a level superior to that of native membranes. PMID:18505730
Rac1 GTPase regulates 11β hydroxysteroid dehydrogenase type 2 and fibrotic remodeling.

PubMed

Lavall, Daniel; Schuster, Pia; Jacobs, Nadine; Kazakov, Andrey; Böhm, Michael; Laufs, Ulrich

2017-05-05

The aim of the study was to characterize the role of Rac1 GTPase for the mineralocorticoid receptor (MR)-mediated pro-fibrotic remodeling. Transgenic mice with cardiac overexpression of constitutively active Rac1 (RacET) develop an age-dependent phenotype with atrial dilatation, fibrosis, and atrial fibrillation. Expression of MR was similar in RacET and WT mice. The expression of 11β hydroxysteroid dehydrogenase type 2 (11β-HSD2) was age-dependently up-regulated in the atria and the left ventricles of RacET mice on mRNA and protein levels. Statin treatment inhibiting Rac1 geranylgeranylation reduced 11β-HSD2 up-regulation. Samples of human left atrial myocardium showed a positive correlation between Rac1 activity and 11β-HSD2 expression ( r = 0.7169). Immunoprecipitation showed enhanced Rac1-bound 11β-HSD2 relative to Rac1 expression in RacET mice that was diminished with statin treatment. Both basal and phorbol 12-myristate 13-acetate (PMA)-induced NADPH oxidase activity were increased in RacET and correlated positively with 11β-HSD2 expression ( r = 0.788 and r = 0.843, respectively). In cultured H9c2 cardiomyocytes, Rac1 activation with l-buthionine sulfoximine increased; Rac1 inhibition with NSC23766 decreased 11β-HSD2 mRNA and protein expression. Connective tissue growth factor (CTGF) up-regulation induced by aldosterone was prevented with NSC23766. Cardiomyocyte transfection with 11β-HSD2 siRNA abolished the aldosterone-induced CTGF up-regulation. Aldosterone-stimulated MR nuclear translocation was blocked by the 11β-HSD2 inhibitor carbenoxolone. In cardiac fibroblasts, nuclear MR translocation induced by aldosterone was inhibited with NSC23766 and spironolactone. NSC23766 prevented the aldosterone-induced proliferation and migration of cardiac fibroblasts and the up-regulation of CTGF and fibronectin. In conclusion, Rac1 GTPase regulates 11β-HSD2 expression, MR activation, and MR-mediated pro-fibrotic signaling. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Rac2 deficiency attenuates CCl4-induced liver injury through suppressing inflammation and oxidative stress.

PubMed

Zou, Yan; Xiong, Ji-Bin; Ma, Ke; Wang, Ai-Zhong; Qian, Ke-Jian

2017-10-01

Oxidative stress is a leading cause to liver injury. Rac2 is a Ras-associated guanosine triphosphatase, an important molecule modulating a large number of cells and involved in the regulation of reactive oxygen species (ROS). For the study described here, we supposed that Rac2 knockout protects mice against CCl 4 -induced acute liver injury. We found that Rac2 expressed highly in CCl 4 -induced liver tissues. CCl 4 -treated Rac2 knockout (Rac2-/-) mice had reduced CD24 levels and steatosis. In addition, CCl 4 -induced high expression of pro-inflammatory cytokines and chemokine were reversed by Rac2 deficiency compared to CCl 4 -treated wild type (WT) mice. We also found that fibrosis-related signals of MMP-9, MMP-2 and TGF-β1 were also down-regulated in Rac2 knockout mice induced by CCl 4 . Significantly, oxidative stress induced by CCl 4 was also suppressed owing to the lack of Rac2, evidenced by enhanced superoxide dismutase (SOD) activity, and reduced malondialdehyde (MDA) levels, superoxide radical, H 2 O 2 , xanthine oxidase (XO), xanthine dehydrogenase (XDH) and XO/XDH ratio. Moreover, c-Jun N-terminal protein kinase mitogen-activated protein kinases (JNK MAPK) was activated by CCl 4 , which was reversed in the liver of Rac2-/- mice through western blot and immunohistochemical analysis. In vitro, endotoxin (LPS) was treated to hepatocytes isolated from WT mice and Rac2-/- mice. The data further confirmed the role of Rac2 deficiency suppressed pro-inflammatory cytokines and chemokine, as well as fibrosis-related signals. Of note, production of ROS induced by LPS was reduced in Rac2-/- cells, accompanied with enhanced SOD1, SOD2 and reduced XO and phosphorylated-JNK expressions. Our results indicated that Rac2 played an essential role in acute liver injury induced by CCl 4 , providing the compelling information of the effects of Rac2 on liver injury, and revealing a novel regulatory mechanism for acute liver injury. Copyright © 2017. Published by Elsevier Masson SAS.
CRISPR-Cas-Mediated Gene Silencing Reveals RacR To Be a Negative Regulator of YdaS and YdaT Toxins in Escherichia coli K-12.

PubMed

Bindal, Gargi; Krishnamurthi, Revathy; Seshasayee, Aswin Sai Narain; Rath, Devashish

2017-01-01

Bacterial genomes are rich in horizontally acquired prophages. racR is an essential gene located in the rac prophage that is resident in many Escherichia coli genomes. Employing a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas-based gene silencing approach, we show that RacR is a negative regulator of the divergently transcribed and adjacent ydaS-ydaT operon in Escherichia coli K-12. Overexpression of YdaS and YdaT due to RacR depletion leads to cell division defects and decrease in survival. We further show that both YdaS and YdaT can act independently as toxins and that RacR serves to counteract the toxicity by tightly downregulating the expression of these toxins. IMPORTANCE racR is an essential gene and one of the many poorly studied genes found on the rac prophage element that is present in many Escherichia coli genomes. Employing a CRISPR-based approach, we have silenced racR expression to various levels and elucidated its physiological consequences. We show that the downregulation of racR leads to upregulation of the adjacent ydaS-ydaT operon. Both YdaS and YdaT act as toxins by perturbing the cell division resulting in enhanced cell killing. This work establishes a physiological role for RacR, which is to keep the toxic effects of YdaS and YdaT in check and promote cell survival. We, thus, provide a rationale for the essentiality of racR in Escherichia coli K-12 strains.
CRISPR-Cas-Mediated Gene Silencing Reveals RacR To Be a Negative Regulator of YdaS and YdaT Toxins in Escherichia coli K-12

PubMed Central

Bindal, Gargi; Krishnamurthi, Revathy; Seshasayee, Aswin Sai Narain

2017-01-01

ABSTRACT Bacterial genomes are rich in horizontally acquired prophages. racR is an essential gene located in the rac prophage that is resident in many Escherichia coli genomes. Employing a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas-based gene silencing approach, we show that RacR is a negative regulator of the divergently transcribed and adjacent ydaS-ydaT operon in Escherichia coli K-12. Overexpression of YdaS and YdaT due to RacR depletion leads to cell division defects and decrease in survival. We further show that both YdaS and YdaT can act independently as toxins and that RacR serves to counteract the toxicity by tightly downregulating the expression of these toxins. IMPORTANCE racR is an essential gene and one of the many poorly studied genes found on the rac prophage element that is present in many Escherichia coli genomes. Employing a CRISPR-based approach, we have silenced racR expression to various levels and elucidated its physiological consequences. We show that the downregulation of racR leads to upregulation of the adjacent ydaS-ydaT operon. Both YdaS and YdaT act as toxins by perturbing the cell division resulting in enhanced cell killing. This work establishes a physiological role for RacR, which is to keep the toxic effects of YdaS and YdaT in check and promote cell survival. We, thus, provide a rationale for the essentiality of racR in Escherichia coli K-12 strains. PMID:29205229
Inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear.

PubMed

Jiang, Lizhu; Mao, Rongrong; Tong, Jianbin; Li, Jinnan; Chai, Anping; Zhou, Qixin; Yang, Yuexiong; Wang, Liping; Li, Lingjiang; Xu, Lin

2016-10-01

Promoting extinction of fear memory is the main treatment of fear disorders, especially post-traumatic stress disorder (PTSD). However, fear extinction is often incomplete in these patients. Our previous study had shown that Rac1 activity in hippocampus plays a crucial role in the learning of contextual fear memory in rats. Here, we further investigated whether Rac1 activity also modulated the extinction of contextual fear memory. We found that massed extinction obviously upregulated hippocampal Rac1 activity and induced long-term extinction of contextual fear in rats. Intrahippocampal injection of the Rac1 inhibitor NSC23766 prevents extinction of contextual fear in massed extinction training rats. In contrast, long-spaced extinction downregulated Rac1 activity and caused less extinction. And Rac1 activator CN04-A promotes extinction of contextual fear in long-spaced extinction rats. Our study demonstrates that inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear, suggesting that modulating Rac1 activity of the hippocampus may be promising therapy of fear disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.
Debates, divisions, and decisions: recombinant DNA advisory committee (RAC) authorization of the first human gene transfer experiments.

PubMed Central

Carmen, I H

1992-01-01

Possibly the most far-reaching, controversial research currently being conducted in the international biological science community involves human gene therapy experimentation. In this paper, I report the dynamics of the political process which ultimately found the Recombinant DNA Advisory Committee (RAC) of the National Institutes of Health approving for the first time protocols of this genre. A full appreciation of the policy-making dialogue shows that significant participants perceived the process from very different vantage points regarding the way in which the American political system works and the way in which it ought to work. I argue that, if we are to understand how the RAC should proceed in orchestrating a human gene therapy policy agenda, then we must flesh out and critically analyze these competing vantage points. To that end, I postulate seven possible "action models" for characterizing how protocol assessments of the type at issue might be developed given the nature of our politics, reaching the conclusion that one of these models holds out the most promise for synthesizing efficaciously the key factors involved. In conclusion, I discuss how the RAC might profitably employ this preferred strategy in these and other cases. PMID:1734711
Aberrant methylation of PSD disturbs Rac1-mediated immune responses governing neutrophil chemotaxis and apoptosis in ulcerative colitis-associated carcinogenesis.

PubMed

Kato, Takaharu; Suzuki, Koichi; Okada, Shinichiro; Kamiyama, Hidenori; Maeda, Takafumi; Saito, Masaaki; Koizumi, Kei; Miyaki, Yuichiro; Konishi, Fumio

2012-04-01

We previously reported that the Pleckstrin and Sec7 domain-containing (PSD) gene is preferentially methylated in patients with ulcerative colitis (UC) who developed colorectal cancer (CRC), and is implicated in UC-associated carcinogenesis through its inhibition of apoptosis. This study aimed to determine the potential effect of PSD methylation on its downstream molecule, Ras-related C3 botulinum toxin substrate 1 (Rac1), which governs neutrophil chemotaxis and apoptosis signaling. PSD was knocked down in a normal human fibroblast cell line (HNDF) and a neutrophil-like cell line (HL-60). Both NHDF and HL-60 cells exhibited numerous filamentous-actin (F-actin) rich membrane extensions, resulting in the activation of Rac1; this activation was hampered by PSD silencing. Lipopolysaccharide, a reactive oxygen species (ROS) inducer, stimulated NHDF cells to release ROS and activated caspase‑3/7 in the presence of neutrophils, which was inhibited by PSD knockdown. Migration assays demonstrated that chemotaxis of HL-60 cells was affected by PSD silencing in NHDF cells. Tissue sections from 6 UC patients with CRC and 15 UC patients without CRC were examined. To verify Rac1-mediated chemotaxis in tissue sections, we evaluated the grade of neutrophil infiltration by histological assessment and assessed F-actin and PSD expression by immunohistochemistry. Neutrophil infiltration, F-actin and PSD expression were significantly decreased in specimens from UC patients with PSD methylation compared with those without. Decreased levels of F-actin expression were observed in colorectal mucosa, as well as in infiltrating cells with PSD methylation. PSD expression was preferentially inhibited in colorectal mucosa by PSD methylation, whereas PSD expression was rarely observed in infiltrating cells, regardless of PSD methylation status. These data indicate that aberrant methylation of PSD occurs in UC-associated colorectal mucosa, enabling circumvention of Rac1-mediated immune responses governing neutrophil chemotaxis and apoptosis, and thus plays a pivotal role in the mechanisms underlying UC-associated carcinogenesis.
Altered focal adhesion regulation correlates with cardiomyopathy in mice expressing constitutively active rac1

PubMed Central

Sussman, Mark A.; Welch, Sara; Walker, Angela; Klevitsky, Raisa; Hewett, Timothy E.; Price, Robert L.; Schaefer, Erik; Yager, Karen

2000-01-01

The ras family of small GTP-binding proteins exerts powerful effects upon cell structure and function. One member of this family, rac, induces actin cytoskeletal reorganization in nonmuscle cells and hypertrophic changes in cultured cardiomyocytes. To examine the effect of rac1 activation upon cardiac structure and function, transgenic mice were created that express constitutively activated rac1 specifically in the myocardium. Transgenic rac1 protein was expressed at levels comparable to endogenous rac levels, with activation of the rac1 signaling pathway resulting in two distinct cardiomyopathic phenotypes: a lethal dilated phenotype associated with neonatal activation of the transgene and a transient cardiac hypertrophy seen among juvenile mice that resolved with age. Neither phenotype showed myofibril disarray and hypertrophic hearts were hypercontractilein working heart analyses. The rac1 target p21-activated kinase translocated from a cytosolic to a cytoskeletal distribution, suggesting that rac1 activation was inducing focal adhesion reorganization. Corroborating results showed altered localizations of src in dilated cardiomyopathy and paxillin in both cardiomyopathic phenotypes. This study, the first examination of rac1-mediated cardiac effects in vivo, demonstrates that dilation and hypertrophy can share a common molecular origin and presents evidence that both timing and concurrent signaling from multiple pathways can influence cardiac remodeling. PMID:10749567
A sequence variant in human KALRN impairs protein function and coincides with reduced cortical thickness

PubMed Central

Russell, Theron A.; Blizinsky, Katherine D.; Cobia, Derin J.; Cahill, Michael; Xie, Zhong; Sweet, Robert A.; Duan, Jubao; Gejman, Pablo V.; Wang, Lei; Csernansky, John G.; Penzes, Peter

2014-01-01

Dendritic spine pathology is a key feature of several neuropsychiatric disorders. The Rac1 guanine nucleotide exchange factor kalirin-7 is critical for spine morphogenesis on cortical pyramidal neurons. Here we identify a rare coding variant in the KALRN gene region that encodes the catalytic domain, in a schizophrenia patient and his sibling with major depressive disorder. The D1338N substitution significantly diminished the protein's ability catalyze the activation of Rac1. Contrary to wild-type kalirin-7, kalirin-7-D1338N failed to increase spine size and density. Both subjects carrying the polymorphism displayed reduced cortical volume in the superior temporal sulcus (STS), a region implicated in schizophrenia. Consistent with this, mice with reduced kalirin expression showed reduced neuropil volume in the rodent homolog of the STS. These data suggest that single amino acid changes in proteins involved in dendritic spine function can have significant effects on the structure and function of the cerebral cortex. PMID:25224588
A sequence variant in human KALRN impairs protein function and coincides with reduced cortical thickness.

PubMed

Russell, Theron A; Blizinsky, Katherine D; Cobia, Derin J; Cahill, Michael E; Xie, Zhong; Sweet, Robert A; Duan, Jubao; Gejman, Pablo V; Wang, Lei; Csernansky, John G; Penzes, Peter

2014-09-16

Dendritic spine pathology is a key feature of several neuropsychiatric disorders. The Rac1 guanine nucleotide exchange factor kalirin-7 is critical for spine morphogenesis on cortical pyramidal neurons. Here we identify a rare coding variant in the KALRN gene region that encodes the catalytic domain, in a schizophrenia patient and his sibling with major depressive disorder. The D1338N substitution significantly diminished the protein's ability to catalyse the activation of Rac1. Contrary to wild-type kalirin-7, kalirin-7-D1338N failed to increase spine size and density. Both subjects carrying the polymorphism displayed reduced cortical volume in the superior temporal sulcus (STS), a region implicated in schizophrenia. Consistent with this, mice with reduced kalirin expression showed reduced neuropil volume in the rodent homologue of the STS. These data suggest that single amino acid changes in proteins involved in dendritic spine function can have significant effects on the structure and function of the cerebral cortex.
In situ detection of the activation of Rac1 and RalA small GTPases in mouse adipocytes by immunofluorescent microscopy following in vivo and ex vivo insulin stimulation.

PubMed

Takenaka, Nobuyuki; Nihata, Yuma; Ueda, Sho; Satoh, Takaya

2017-11-01

Rac1 has been implicated in insulin-dependent glucose uptake by mechanisms involving plasma membrane translocation of the glucose transporter GLUT4 in skeletal muscle. Although the uptake of glucose is also stimulated by insulin in adipose tissue, the role for Rac1 in adipocyte insulin signaling remains controversial. As a step to reveal the role for Rac1 in adipocytes, we aimed to establish immunofluorescent microscopy to detect the intracellular distribution of activated Rac1. The epitope-tagged Rac1-binding domain of a Rac1-specific target was utilized as a probe that specifically recognizes the activated form of Rac1. Rac1 activation in response to ex vivo and in vivo insulin stimulations in primary adipocyte culture and mouse white adipose tissue, respectively, was successfully observed by immunofluorescent microscopy. These Rac1 activations were mediated by phosphoinositide 3-kinase. Another small GTPase RalA has also been implicated in insulin-stimulated glucose uptake in skeletal muscle and adipose tissue. Similarly to Rac1, immunofluorescent microscopy using an activated RalA-specific polypeptide probe allowed us to detect intracellular distribution of insulin-activated RalA in adipocytes. These novel approaches to visualize the activation status of small GTPases in adipocytes will largely contribute to the understanding of signal transduction mechanisms particularly for insulin action. Copyright © 2017 Elsevier Inc. All rights reserved.
Hippocampal Activation of Rac1 Regulates the Forgetting of Object Recognition Memory.

PubMed

Liu, Yunlong; Du, Shuwen; Lv, Li; Lei, Bo; Shi, Wei; Tang, Yikai; Wang, Lianzhang; Zhong, Yi

2016-09-12

Forgetting is a universal feature for most types of memories. The best-defined and extensively characterized behaviors that depict forgetting are natural memory decay and interference-based forgetting [1, 2]. Molecular mechanisms underlying the active forgetting remain to be determined for memories in vertebrates. Recent progress has begun to unravel such mechanisms underlying the active forgetting [3-11] that is induced through the behavior-dependent activation of intracellular signaling pathways. In Drosophila, training-induced activation of the small G protein Rac1 mediates natural memory decay and interference-based forgetting of aversive conditioning memory [3]. In mice, the activation of photoactivable-Rac1 in recently potentiated spines in a motor learning task erases the motor memory [12]. These lines of evidence prompted us to investigate a role for Rac1 in time-based natural memory decay and interference-based forgetting in mice. The inhibition of Rac1 activity in hippocampal neurons through targeted expression of a dominant-negative Rac1 form extended object recognition memory from less than 72 hr to over 72 hr, whereas Rac1 activation accelerated memory decay within 24 hr. Interference-induced forgetting of this memory was correlated with Rac1 activation and was completely blocked by inhibition of Rac1 activity. Electrophysiological recordings of long-term potentiation provided independent evidence that further supported a role for Rac1 activation in forgetting. Thus, Rac1-dependent forgetting is evolutionarily conserved from invertebrates to vertebrates. Copyright © 2016 Elsevier Ltd. All rights reserved.
Effects of Added Zinc on Skeletal Muscle Morphometrics and Gene Expression of Finishing Pigs Fed Ractopamine-HCL.

PubMed

Burnett, D D; Paulk, C B; Tokach, M D; Nelssen, J L; Vaughn, M A; Phelps, K J; Dritz, S S; DeRouchey, J M; Goodband, R D; Haydon, K D; Gonzalez, J M

2016-01-01

Finishing pigs (n = 320) were used in a 35-day study to determine the effects of ractopamine-HCl (RAC) and supplemental Zinc (Zn) level on loin eye area (LEA) and gene expression. Pens were randomly allotted to the following treatments for the final 35 days on feed: a corn-soybean meal diet (CON), a diet with 10 ppm RAC (RAC+), and RAC diet plus added Zn at 75, 150, or 225 ppm. Sixteen pigs per treatment were randomly selected for collection of serial muscle biopsies and carcass data on day 0, 8, 18, and 32 of the treatment phase. Compared to CON carcasses, RAC+ carcasses had 12.6% larger (P = 0.03) LEA. Carcasses from RAC diets with added Zn had a tendency for increased (quadratic, P < 0.10) LEA compared to the RAC+ carcasses. Compared to RAC+ pigs, relative expression of IGF1 decreased with increasing levels of Zn on day 8 and 18 of treatment, but expression levels were similar on day 32 due to Zn treatments increasing in expression while the RAC+ treatment decreased (Zn quadratic × day quadratic, P = 0.04). A similar trend was detected for the expression of β1-receptor where expression levels in the RAC+ pigs were greater than Zn supplemented pigs on day 8 and 18 of the experiment, but the magnitude of difference between the treatments was reduced on day 32 due to a decrease in expression by RAC+ pigs and an increase in expression by the Zn pigs (Zn quadratic × day quadratic, P = 0.01). The ability of Zn to prolong the expression of these two genes may be responsible for the tendency of Zn to increase LEA in RAC supplemented pigs.
78 FR 78810 - Pacific Southwest Recreation Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

...The Pacific Southwest Recreation Resource Advisory Committee (Recreation RAC) will meet in San Bernardino, California. The Recreation RAC is authorized under the Federal Lands Recreation Enhancement Act (REA) (Pub. L. 108-447) and operates in compliance with the Federal Advisory Committee Act (FACA) (Pub. L. 92-463). Additional information concerning the Recreation RAC can be found by visiting the Recreation RAC's Web site at: http://www.fs.usda.gov/main/r5/ recreation/racs.
Characterization of a RacGTPase up-regulated in the large yellow croaker Pseudosciaena crocea immunity.

PubMed

Han, Fang; Wang, Xiaoqing; Yang, Qilian; Cai, Mingyi; Wang, Zhi Yong

2011-02-01

The Rac proteins are members of the Rho family of small G proteins and are implicated in the regulation of several pathways, including those leading to cytoskeleton reorganization, gene expression, cell proliferation, cell adhesion and cell migration and survival. In this investigation, a Rac gene (named as LycRac gene) was obtained from the large yellow croaker and it was expressed in Escherichia coli and purified. Subsequently the specific antibody was raised using the purified fusion protein (GST-LycRac). Moreover, the GTP-binding assay showed that the LycRac protein had GTP-binding activity. The LycRac gene was ubiquitously transcribed and expressed in 9 tissues. Quantitative real-time RT-PCR and Western blot analysis revealed the highest expression in gill and the weakest expression in spleen. Time-course analysis revealed that LycRac expression was obviously up-regulated in blood, spleen and liver after immunization with polyinosinic polycytidynic acid (poly I:C), formalin-inactive Gram-negative bacterium Vibrio parahemolyticus and bacterial lipopolysaccharides (LPS). These results suggested that LycRac protein might play an important role in the immune response against microorganisms in large yellow croaker. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.
Deletion of epidermal Rac1 inhibits HPV-8 induced skin papilloma formation and facilitates HPV-8- and UV-light induced skin carcinogenesis

PubMed Central

Deshmukh, Jayesh; Pofahl, Ruth; Pfister, Herbert; Haase, Ingo

2016-01-01

Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has not been investigated so far, solar UV radiation being an important carcinogen to the skin. To investigate this, we deleted Rac1 or modulated its activity in mice with transgenic expression of Human papilloma virus type-8 (HPV-8) in epidermal keratinocytes. Our data show that inhibition or deletion of Rac1 results in reduced papilloma formation upon UV-irradiation with a single dose, whereas constitutive activation of Rac1 strongly increases papilloma frequency in these mice. Surprisingly, we observed that, upon chronic UV-irradiation, the majority of mice with transgenic expression of HPV-8 and epidermis specific Rac1 deletion developed squamous cell carcinomas. Taken together, our data show that Rac1 exerts a dual role in skin carcinogenesis: its activation is, on one hand, required for HPV-8- and UV-light induced papilloma formation but, on the other, suppresses the development of squamous cell carcinomas. PMID:27506937
Deletion of epidermal Rac1 inhibits HPV-8 induced skin papilloma formation and facilitates HPV-8- and UV-light induced skin carcinogenesis.

PubMed

Deshmukh, Jayesh; Pofahl, Ruth; Pfister, Herbert; Haase, Ingo

2016-09-06

Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has not been investigated so far, solar UV radiation being an important carcinogen to the skin.To investigate this, we deleted Rac1 or modulated its activity in mice with transgenic expression of Human papilloma virus type-8 (HPV-8) in epidermal keratinocytes. Our data show that inhibition or deletion of Rac1 results in reduced papilloma formation upon UV-irradiation with a single dose, whereas constitutive activation of Rac1 strongly increases papilloma frequency in these mice. Surprisingly, we observed that, upon chronic UV-irradiation, the majority of mice with transgenic expression of HPV-8 and epidermis specific Rac1 deletion developed squamous cell carcinomas. Taken together, our data show that Rac1 exerts a dual role in skin carcinogenesis: its activation is, on one hand, required for HPV-8- and UV-light induced papilloma formation but, on the other, suppresses the development of squamous cell carcinomas.
Extending the Impact of RAC1b Overexpression to Follicular Thyroid Carcinomas

PubMed Central

Faria, Márcia; Capinha, Liliana; Simões-Pereira, Joana; Bugalho, Maria João; Silva, Ana Luísa

2016-01-01

RAC1b is a hyperactive variant of the small GTPase RAC1 known to be a relevant molecular player in different cancers. Previous studies from our group lead to the evidence that its overexpression in papillary thyroid carcinoma (PTC) is associated with an unfavorable prognosis. In the present study, we intended to extend the analysis of RAC1b expression to thyroid follicular neoplasms and to seek for clinical correlations. RAC1b expression levels were determined by RT-qPCR in thyroid follicular tumor samples comprising 23 follicular thyroid carcinomas (FTCs) and 33 follicular thyroid adenomas (FTAs). RAC1b was found to be overexpressed in 33% of carcinomas while no RAC1b overexpression was documented among follicular adenomas. Patients with a diagnosis of FTC were divided into two groups based on longitudinal evolution and final outcome. RAC1b overexpression was significantly associated with both the presence of distant metastases (P = 0.01) and poorer clinical outcome (P = 0.01) suggesting that, similarly to that previously found in PTCs, RAC1b overexpression in FTCs is also associated with worse outcomes. Furthermore, the absence of RAC1b overexpression in follicular adenomas hints its potential as a molecular marker likely to contribute, in conjunction with other putative markers, to the preoperative differential diagnosis of thyroid follicular lesions. PMID:27127508

Augmented Rac1 Expression and Activity are Associated with Oxidative Stress and Decline of β Cell Function in Obesity.

PubMed

Zhou, Shutong; Yu, Dongni; Ning, Shangyong; Zhang, Heli; Jiang, Lei; He, Lei; Li, Miao; Sun, Mingxiao

2015-01-01

The aim of this study was to clarify the relationship among Rac1 expression and activation, oxidative stress and β cell dysfunction in obesity. In vivo, serum levels of glucose, insulin, oxidative stress markers and Rac1 expression were compared between ob/ob mice and C57BL/6J controls. Then, these variables were rechecked after the administration of the specific Rac1 inhibitor-NSC23766 in ob/ob mice. In vitro, NIT-1 β cells were cultured in a hyperglycemic and/or hyperlipidemic state with or without NSC23766, and the differences of Rac1 expression and translocation, NADPH oxidase(Nox) enzyme activity, reactive oxygen species (ROS) and insulin mRNA were observed. ob/ob mice displayed abnormal glycometabolism, oxidative stress and excessive expression of Rac1 in the pancreas. NSC23766 injection inhibited the expression of Rac1 in the pancreas, along with amelioration of oxidative stress and glycometabolism in obese mice. Under hyperglycemic and/or hyperlipidemic conditions, Rac1 translocated to the cellular membrane, induced activation of the NADPH oxidase enzyme and oxidative stress, and simultaneously reduced the insulin mRNA expression in NIT-1 β cells. Inhibiting Rac1 activity could alleviate oxidative stress and meliorate the decline of insulin mRNA in β cells. Rac1 might contribute to oxidative stress systemically and locally in the pancreas in obesity. The excessive activation and expression of Rac1 in obesity were associated with β cell dysfunction through ROS production. © 2015 S. Karger AG, Basel.
Selective Rac1 inhibition protects renal tubular epithelial cells from oxalate-induced NADPH oxidase-mediated oxidative cell injury

PubMed Central

Thamilselvan, Vijayalakshmi; Menon, Mani

2013-01-01

Oxalate-induced oxidative cell injury is one of the major mechanisms implicated in calcium oxalate nucleation, aggregation and growth of kidney stones. We previously demonstrated that oxalate-induced NADPH oxidase-derived free radicals play a significant role in renal injury. Since NADPH oxidase activation requires several regulatory proteins, the primary goal of this study was to characterize the role of Rac GTPase in oxalate-induced NADPH oxidase-mediated oxidative injury in renal epithelial cells. Our results show that oxalate significantly increased membrane translocation of Rac1 and NADPH oxidase activity of renal epithelial cells in a time-dependent manner. We found that NSC23766, a selective inhibitor of Rac1, blocked oxalate-induced membrane translocation of Rac1 and NADPH oxidase activity. In the absence of Rac1 inhibitor, oxalate exposure significantly increased hydrogen peroxide formation and LDH release in renal epithelial cells. In contrast, Rac1 inhibitor pretreatment, significantly decreased oxalate-induced hydrogen peroxide production and LDH release. Furthermore, PKC α and δ inhibitor, oxalate exposure did not increase Rac1 protein translocation, suggesting that PKC resides upstream from Rac1 in the pathway that regulates NADPH oxidase. In conclusion, our data demonstrate for the first time that Rac1-dependent activation of NADPH oxidase might be a crucial mechanism responsible for oxalate-induced oxidative renal cell injury. These findings suggest that Rac1 signaling plays a key role in oxalate-induced renal injury, and may serve as a potential therapeutic target to prevent calcium oxalate crystal deposition in stone formers and reduce recurrence. PMID:21814770
IbeA and OmpA of Escherichia coli K1 Exploit Rac1 Activation for Invasion of Human Brain Microvascular Endothelial Cells

PubMed Central

Maruvada, Ravi

2012-01-01

Meningitis-causing Escherichia coli K1 internalization of the blood-brain barrier is required for penetration into the brain, but the host-microbial interactions involved in E. coli entry of the blood-brain barrier remain incompletely understood. We show here that a meningitis-causing E. coli K1 strain RS218 activates Rac1 (GTP-Rac1) of human brain microvascular endothelial cells (HBMEC) in a time-dependent manner. Both activation and bacterial invasion were significantly inhibited in the presence of a Rac1 inhibitor. We further showed that the guanine nucleotide exchange factor Vav2, not β-Pix, was involved in E. coli K1-mediated Rac1 activation. Since activated STAT3 is known to bind GTP-Rac1, the relationship between STAT3 and Rac1 was examined in E. coli K1 invasion of HBMEC. Downregulation of STAT3 resulted in significantly decreased E. coli invasion compared to control HBMEC, as well as a corresponding decrease in GTP-Rac1, suggesting that Rac1 activation in response to E. coli is under the control of STAT3. More importantly, two E. coli determinants contributing to HBMEC invasion, IbeA and OmpA, were shown to affect both Rac1 activation and their association with STAT3. These findings demonstrate for the first time that specific E. coli determinants regulate a novel mechanism of STAT3 cross talk with Rac1 in E. coli K1 invasion of HBMEC. PMID:22451524
IbeA and OmpA of Escherichia coli K1 exploit Rac1 activation for invasion of human brain microvascular endothelial cells.

PubMed

Maruvada, Ravi; Kim, Kwang Sik

2012-06-01

Meningitis-causing Escherichia coli K1 internalization of the blood-brain barrier is required for penetration into the brain, but the host-microbial interactions involved in E. coli entry of the blood-brain barrier remain incompletely understood. We show here that a meningitis-causing E. coli K1 strain RS218 activates Rac1 (GTP-Rac1) of human brain microvascular endothelial cells (HBMEC) in a time-dependent manner. Both activation and bacterial invasion were significantly inhibited in the presence of a Rac1 inhibitor. We further showed that the guanine nucleotide exchange factor Vav2, not β-Pix, was involved in E. coli K1-mediated Rac1 activation. Since activated STAT3 is known to bind GTP-Rac1, the relationship between STAT3 and Rac1 was examined in E. coli K1 invasion of HBMEC. Downregulation of STAT3 resulted in significantly decreased E. coli invasion compared to control HBMEC, as well as a corresponding decrease in GTP-Rac1, suggesting that Rac1 activation in response to E. coli is under the control of STAT3. More importantly, two E. coli determinants contributing to HBMEC invasion, IbeA and OmpA, were shown to affect both Rac1 activation and their association with STAT3. These findings demonstrate for the first time that specific E. coli determinants regulate a novel mechanism of STAT3 cross talk with Rac1 in E. coli K1 invasion of HBMEC.
42 CFR 455.510 - Payments to RACs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 4 2011-10-01 2011-10-01 false Payments to RACs. 455.510 Section 455.510 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....510 Payments to RACs. (a) General. Fees paid to RACs must be made only from amounts recovered. (b...
Chemical speciation and risk assessment of cadmium in soils around a typical coal mining area of China.

PubMed

Cheng, Siwei; Liu, Guijian; Zhou, Chuncai; Sun, Ruoyu

2018-05-21

The distribution characteristics of Cadmium (Cd) fractions in soils around a coal mining area of Huaibei coalfield were investigated, with the aim to assess its ecological risk. The total Cd concentrations in soils ranged from 0.05 to 0.87 mg/kg. The high percentage of phyto-available Cd (58%) when redox or base-acid equilibria changed. Soil pH was found to be a crucial factor affecting soil Cd fraction, and carbonate-bound Cd can be significantly affected by both organic matter and pH of soils. The static ecological evaluation models, including potential ecological risk index (PERI), geo-accumulation index (I geo ) and risk assessment code (RAC), revealed a moderate soil Cd contamination and prensented high Cd exposure risk in studied soils. However, the dynamic evaluation of Cd risk, determined using a delayed geochemical hazard (DGH), suggested that our studied soils can be classified as median-risk with a mean probability of 24.79% for Cd DGH. These results provide a better assessment for the risk development of Cd contamination in coal mining areas. Copyright © 2018 Elsevier Inc. All rights reserved.
Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites.

PubMed

Chen, Baoyu; Chou, Hui-Ting; Brautigam, Chad A; Xing, Wenmin; Yang, Sheng; Henry, Lisa; Doolittle, Lynda K; Walz, Thomas; Rosen, Michael K

2017-09-26

The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly.
Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans*

PubMed Central

Xiang, Richard F.; Stack, Danuta; Huston, Shaunna M.; Li, Shu Shun; Ogbomo, Henry; Kyei, Stephen K.; Mody, Christopher H.

2016-01-01

The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found that Cryptococcus neoformans independently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing, Cryptococcus initiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity against C. neoformans. Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to kill C. neoformans. PMID:26867574
How do we know? An assessment of integrated community case management data quality in four districts of Malawi.

PubMed

Yourkavitch, Jennifer; Zalisk, Kirsten; Prosnitz, Debra; Luhanga, Misheck; Nsona, Humphreys

2016-11-01

The World Health Organization contracted annual data quality assessments of Rapid Access Expansion (RAcE) projects to review integrated community case management (iCCM) data quality and the monitoring and evaluation (M&E) system for iCCM, and to suggest ways to improve data quality. The first RAcE data quality assessment was conducted in Malawi in January 2014 and we present findings pertaining to data from the health management information system at the community, facility and other sub-national levels because RAcE grantees rely on that for most of their monitoring data. We randomly selected 10 health facilities (10% of eligible facilities) from the four RAcE project districts, and collected quantitative data with an adapted and comprehensive tool that included an assessment of Malawi's M&E system for iCCM data and a data verification exercise that traced selected indicators through the reporting system. We rated the iCCM M&E system across five function areas based on interviews and observations, and calculated verification ratios for each data reporting level. We also conducted key informant interviews with Health Surveillance Assistants and facility, district and central Ministry of Health staff. Scores show a high-functioning M&E system for iCCM with some deficiencies in data management processes. The system lacks quality controls, including data entry verification, a protocol for addressing errors, and written procedures for data collection, entry, analysis and management. Data availability was generally high except for supervision data. The data verification process identified gaps in completeness and consistency, particularly in Health Surveillance Assistants' record keeping. Staff at all levels would like more training in data management. This data quality assessment illuminates where an otherwise strong M&E system for iCCM fails to ensure some aspects of data quality. Prioritizing data management with documented protocols, additional training and approaches to create efficient supervision practices may improve iCCM data quality. © The Author 2016. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Direct multiplex imaging and optogenetics of Rho GTPases enabled by near-infrared FRET.

PubMed

Shcherbakova, Daria M; Cox Cammer, Natasha; Huisman, Tsipora M; Verkhusha, Vladislav V; Hodgson, Louis

2018-06-01

Direct visualization and light control of several cellular processes is a challenge, owing to the spectral overlap of available genetically encoded probes. Here we report the most red-shifted monomeric near-infrared (NIR) fluorescent protein, miRFP720, and the fully NIR Förster resonance energy transfer (FRET) pair miRFP670-miRFP720, which together enabled design of biosensors compatible with CFP-YFP imaging and blue-green optogenetic tools. We developed a NIR biosensor for Rac1 GTPase and demonstrated its use in multiplexed imaging and light control of Rho GTPase signaling pathways. Specifically, we combined the Rac1 biosensor with CFP-YFP FRET biosensors for RhoA and for Rac1-GDI binding, and concurrently used the LOV-TRAP tool for upstream Rac1 activation. We directly observed and quantified antagonism between RhoA and Rac1 dependent on the RhoA-downstream effector ROCK; showed that Rac1 activity and GDI binding closely depend on the spatiotemporal coordination between these two molecules; and simultaneously observed Rac1 activity during optogenetic manipulation of Rac1.
Role of the Rho GTPase Rac in the activation of the phagocyte NADPH oxidase

PubMed Central

Pick, Edgar

2014-01-01

The superoxide-generating NADPH oxidase of phagocytes consists of the membrane-associated cytochrome b558 (a heterodimer of Nox2 and p22phox) and 4 cytosolic components: p47phox, p67phox, p40phox, and the small GTPase, Rac, in complex with RhoGDI. Superoxide is produced by the NADPH-driven reduction of molecular oxygen, via a redox gradient located in Nox2. Electron flow in Nox2 is initiated by interaction with cytosolic components, which translocate to the membrane, p67phox playing the central role. The participation of Rac is expressed in the following sequence: (1) Translocation of the RacGDP-RhoGDI complex to the membrane; (2) Dissociation of RacGDP from RhoGDI; (3) GDP to GTP exchange on Rac, mediated by a guanine nucleotide exchange factor; (4) Binding of RacGTP to p67phox; (5) Induction of a conformational change in p67phox, promoting interaction with Nox2. The particular involvement of Rac in NADPH oxidase assembly serves as a paradigm for signaling by Rho GTPases, in general. PMID:24598074
A Rac Homolog Is Required for Induction of Hyphal Growth in the Dimorphic Yeast Yarrowia lipolytica

PubMed Central

Hurtado, Cleofe A. R.; Beckerich, Jean-Marie; Gaillardin, Claude; Rachubinski, Richard A.

2000-01-01

Dimorphism in fungi is believed to constitute a mechanism of response to adverse conditions and represents an important attribute for the development of virulence by a number of pathogenic fungal species. We have isolated YlRAC1, a gene encoding a 192-amino-acid protein that is essential for hyphal growth in the dimorphic yeast Yarrowia lipolytica and which represents the first Rac homolog described for fungi. YlRAC1 is not an essential gene, and its deletion does not affect the ability to mate or impair actin polarization in Y. lipolytica. However, strains lacking functional YlRAC1 show alterations in cell morphology, suggesting that the function of YlRAC1 may be related to some aspect of the polarization of cell growth. Northern blot analysis showed that transcription of YlRAC1 increases steadily during the yeast-to-hypha transition, while Southern blot analysis of genomic DNA suggested the presence of several RAC family members in Y. lipolytica. Interestingly, strains lacking functional YlRAC1 are still able to grow as the pseudohyphal form and to invade agar, thus pointing to a function for YlRAC1 downstream of MHY1, a previously isolated gene encoding a C2H2-type zinc finger protein with the ability to bind putative stress response elements and whose activity is essential for both hyphal and pseudohyphal growth in Y. lipolytica. PMID:10762235
Expression and activity of Rac1 is negatively affected in the dehydroepiandrosterone induced polycystic ovary of mouse

PubMed Central

2014-01-01

Background Polycystic ovarian syndrome (PCOS) is characterized by the presence of multiple follicular cysts, giving rise to infertility due to anovulation. This syndrome affects about 10% of women, worldwide. The exact molecular mechanism leading to PCOS remains obscure. RhoGTPase has been associated with oogenesis, but its role in PCOS remains unexplored. Therefore, we attempted to elucidate the Vav-Rac1 signaling in PCOS mice model. Methods We generated a PCOS mice model by injecting dehydroepiandrosterone (DHEA) for a period of 20 days. The expression levels of Rac1, pRac1, Vav, pVav and Caveolin1 were analyzed by employing immuno-blotting and densitometry. The association between Vav and Rac1 proteins were studied by immuno-precipitation. Furthermore, we analyzed the activity of Rac1 and levels of inhibin B and 17β-estradiol in ovary using biochemical assays. Results The presence of multiple follicular cysts in ovary were confirmed by histology. The activity of Rac1 (GTP bound state) was significantly reduced in the PCOS ovary. Similarly, the expression levels of Rac1 and its phosphorylated form (pRac1) were decreased in PCOS in comparison to the sham ovary. The expression level and activity (phosphorylated form) of guanine nucleotide exchanger of Rac1, Vav, was moderately down-regulated. We observed comparatively increased expressions of Caveolin1, 17β-estradiol, and inhibin B in the polycystic ovary. Conclusion We conclude that hyperandrogenization (PCOS) by DHEA diminishes ovarian Rac1 and Vav expression and activity along with an increase in expression of Caveolin1. This is accompanied by an increase in the intra-ovarian level of '17 β-estradiol and inhibin B. PMID:24628852
Decreased concentrations of soluble interleukin-1 receptor accessory protein levels in the peritoneal fluid of women with endometriosis.

PubMed

Michaud, Nadège; Al-Akoum, Mahéra; Gagnon, Geneviève; Girard, Karine; Blanchet, Pierre; Rousseau, Julie Anne; Akoum, Ali

2011-12-01

Interleukin 1 (IL1) may play an important role in endometriosis-associated pelvic inflammation, and natural specific inhibitors, including soluble IL1 receptor accessory protein (sIL1RAcP) and soluble IL1 receptor type 2 (sIL1R2), are critical for counterbalancing the pleiotropic effects of IL1. The objective of this study was to evaluate the levels of sIL1RAcP, together with those of sIL1R2 and IL1β, in the peritoneal fluid of women with and without endometriosis. Peritoneal fluid samples were obtained at laparoscopy and assessed by ELISA. sIL1RAcP concentrations were reduced in endometriosis stages I-II and III-IV. sIL1R2 concentrations were decreased, and those of IL1β were significantly increased in endometriosis stages I-II. sIL1RAcP and sIL1R2 concentrations were significantly decreased in the secretory phase of the menstrual cycle, and IL1β concentrations were elevated in the proliferative and the secretory phases. sIL1RAcP and sIL1R2 concentrations were reduced in women with endometriosis who were infertile, fertile, suffering from pelvic pain or pain-free. However, IL1β concentrations were significantly reduced in women with endometriosis who were infertile or had pelvic pain. These changes may exacerbate the local peritoneal inflammatory reaction observed in women with endometriosis and contribute to endometriosis pathophysiology and the major symptoms of this disease. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
An activating mutant of Rac1 that fails to interact with Rho GDP-dissociation inhibitor stimulates membrane ruffling in mammalian cells.

PubMed Central

Gandhi, Payal N; Gibson, Richard M; Tong, Xiaofeng; Miyoshi, Jun; Takai, Yoshimi; Konieczkowski, Martha; Sedor, John R; Wilson-Delfosse, Amy L

2004-01-01

Rac1, a member of the Rho family of small GTP-binding proteins, is involved in the regulation of the actin cytoskeleton via activation of lamellipodia and membrane ruffle formation. RhoGDI (Rho-family-specific GDP-dissociation inhibitor) forms a complex with Rho proteins in the cytosol of mammalian cells. It not only regulates guanine nucleotide binding to Rho proteins, but may also function as a molecular shuttle to carry Rho proteins from an inactive cytosolic pool to the membrane for activation. These studies tested if RhoGDI is necessary for the translocation of Rac1 from the cytosol to the plasma membrane for the formation of membrane ruffles. We describe a novel mutant of Rac1, R66E (Arg66-->Glu), that fails to bind RhoGDI. This RhoGDI-binding-defective mutation is combined with a Rac1-activating mutation G12V, resulting in a double-mutant [Rac1(G12V/R66E)] that fails to interact with RhoGDI in COS-7 cells, but remains constitutively activated. This double mutant stimulates membrane ruffling to a similar extent as that observed after epidermal growth factor treatment of non-transfected cells. To confirm that Rac1 can signal ruffle formation in the absence of interaction with RhoGDI, Rac1(G12V) was overexpressed in cultured mesangial cells derived from a RhoGDI knockout mouse. Rac1-mediated membrane ruffling was indistinguishable between the RhoGDI(-/-) and RhoGDI(+/+) cell lines. In both the COS-7 and cultured mesangial cells, Rac1(G12V) and Rac1(G12V/R66E) co-localize with membrane ruffles. These findings suggest that interaction with RhoGDI is not essential in the mechanism by which Rac1 translocates to the plasma membrane to stimulate ruffle formation. PMID:14629200
Functional characterization and cellular dynamics of the CDC-42 - RAC - CDC-24 module in Neurospora crassa.

PubMed

Araujo-Palomares, Cynthia L; Richthammer, Corinna; Seiler, Stephan; Castro-Longoria, Ernestina

2011-01-01

Rho-type GTPases are key regulators that control eukaryotic cell polarity, but their role in fungal morphogenesis is only beginning to emerge. In this study, we investigate the role of the CDC-42 - RAC - CDC-24 module in Neurospora crassa. rac and cdc-42 deletion mutants are viable, but generate highly compact colonies with severe morphological defects. Double mutants carrying conditional and loss of function alleles of rac and cdc-42 are lethal, indicating that both GTPases share at least one common essential function. The defects of the GTPase mutants are phenocopied by deletion and conditional alleles of the guanine exchange factor (GEF) cdc-24, and in vitro GDP-GTP exchange assays identify CDC-24 as specific GEF for both CDC-42 and RAC. In vivo confocal microscopy shows that this module is organized as membrane-associated cap that covers the hyphal apex. However, the specific localization patterns of the three proteins are distinct, indicating different functions of RAC and CDC-42 within the hyphal tip. CDC-42 localized as confined apical membrane-associated crescent, while RAC labeled a membrane-associated ring excluding the region labeled by CDC42. The GEF CDC-24 occupied a strategic position, localizing as broad apical membrane-associated crescent and in the apical cytosol excluding the Spitzenkörper. RAC and CDC-42 also display distinct localization patterns during branch initiation and germ tube formation, with CDC-42 accumulating at the plasma membrane before RAC. Together with the distinct cellular defects of rac and cdc-42 mutants, these localizations suggest that CDC-42 is more important for polarity establishment, while the primary function of RAC may be maintaining polarity. In summary, this study identifies CDC-24 as essential regulator for RAC and CDC-42 that have common and distinct functions during polarity establishment and maintenance of cell polarity in N. crassa.
Ionising Radiation Immediately Impairs Synaptic Plasticity-Associated Cytoskeletal Signalling Pathways in HT22 Cells and in Mouse Brain: An In Vitro/In Vivo Comparison Study

PubMed Central

Kempf, Stefan J.; Buratovic, Sonja; von Toerne, Christine; Moertl, Simone; Stenerlöw, Bo; Hauck, Stefanie M.; Atkinson, Michael J.; Eriksson, Per; Tapio, Soile

2014-01-01

Patients suffering from brain malignancies are treated with high-dose ionising radiation. However, this may lead to severe learning and memory impairment. Preventive treatments to minimise these side effects have not been possible due to the lack of knowledge of the involved signalling pathways and molecular targets. Mouse hippocampal neuronal HT22 cells were irradiated with acute gamma doses of 0.5 Gy, 1.0 Gy and 4.0 Gy. Changes in the cellular proteome were investigated by isotope-coded protein label technology and tandem mass spectrometry after 4 and 24 hours. To compare the findings with the in vivo response, male NMRI mice were irradiated on postnatal day 10 with a gamma dose of 1.0 Gy, followed by evaluation of the cellular proteome of hippocampus and cortex 24 hours post-irradiation. Analysis of the in vitro proteome showed that signalling pathways related to synaptic actin-remodelling were significantly affected at 1.0 Gy and 4.0 Gy but not at 0.5 Gy after 4 and 24 hours. We observed radiation-induced reduction of the miR-132 and Rac1 levels; miR-132 is known to regulate Rac1 activity by blocking the GTPase-activating protein p250GAP. In the irradiated hippocampus and cortex we observed alterations in the signalling pathways similar to those in vitro. The decreased expression of miR-132 and Rac1 was associated with an increase in hippocampal cofilin and phospho-cofilin. The Rac1-Cofilin pathway is involved in the modulation of synaptic actin filament formation that is necessary for correct spine and synapse morphology to enable processes of learning and memory. We suggest that acute radiation exposure leads to rapid dendritic spine and synapse morphology alterations via aberrant cytoskeletal signalling and processing and that this is associated with the immediate neurocognitive side effects observed in patients treated with ionising radiation. PMID:25329592
Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1.

PubMed

Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian; Richter, Erik A; Jensen, Thomas E

2015-02-01

Rac1 regulates stretch-stimulated (i.e. mechanical stress) glucose transport in muscle. Actin depolymerization decreases stretch-induced glucose transport in skeletal muscle. Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30-50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40-50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30-40% in tension developing muscle but did not affect contraction-stimulated glucose transport in muscles in which force development was prevented. Our findings suggest that Rac1 and the actin cytoskeleton regulate stretch-stimulated glucose transport and that Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.
Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1

PubMed Central

Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian; Richter, Erik A; Jensen, Thomas E

2015-01-01

An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30–50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40–50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30–40% in tension developing muscle but did not affect contraction-stimulated glucose transport in muscles in which force development was prevented. Our findings suggest that Rac1 and the actin cytoskeleton regulate stretch-stimulated glucose transport and that Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. Key points Rac1 regulates stretch-stimulated (i.e. mechanical stress) glucose transport in muscle. Actin depolymerization decreases stretch-induced glucose transport in skeletal muscle. Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. PMID:25416624
Dying at home in rural residential aged care: A mixed-methods study in the Snowy Monaro region, Australia.

PubMed

Rainsford, Suzanne; Phillips, Christine B; Glasgow, Nicholas J; MacLeod, Roderick D; Wiles, Robert B

2018-05-16

Residential aged care (RAC) is a significant provider of end-of-life care for people aged 65 years and older. Rural residents perceive themselves as different to their urban counterparts. Most studies describing place of death (PoD) in RAC are quantitative and reflect an urban voice. Using a mixed-methods design, this paper examines the PoD of 80 RAC residents (15 short-stay residents who died in RAC during respite or during an attempted step-down transition from hospital to home, and 65 permanent residents), within the rural Snowy Monaro region, Australia, who died between 1 February 2015 and 31 May 2016. Death data were collected from local funeral directors, RAC facilities, one multi-purpose heath service and obituary notices in the local media. The outcome variable was PoD: RAC, local hospital or out-of-region tertiary hospital. For the permanent RAC residents, the outcome of interest was dying in RAC or dying in hospital. Cross tabulations by PoD and key demographic data were performed. Pearson Chi squared tests and exact p-values were used to determine if any of the independent variables were associated with PoD. Using an ethnographic approach, data were collected from 12 face-to-face, open-ended interviews with four RAC residents, with a life expectancy of ≤6 months, and six family caregivers. Interviews were audio-recorded, transcribed and analysed thematically. Fifty-one (78.5%) of the permanent residents died in RAC; 21.5% died in hospital. Home was the initial preferred POD for most interviewed participants; most eventually accepted the transfer to RAC. Long-term residents considered RAC to be their "home"-a familiar place, and an important part of their rural community. The participants did not consider a transfer to hospital to be necessary for end-of-life care. Further work is required to explore further the perspectives of rural RAC residents and their families, and if transfers to hospital are avoidable. © 2018 John Wiley & Sons Ltd.

A Prenylated p47phox-p67phox-Rac1 Chimera Is a Quintessential NADPH Oxidase Activator

PubMed Central

Mizrahi, Ariel; Berdichevsky, Yevgeny; Casey, Patrick J.; Pick, Edgar

2010-01-01

The superoxide-generating NADPH oxidase complex of resting phagocytes includes cytochrome b559, a membrane-associated heterodimer composed of two subunits (Nox2 and p22phox), and four cytosolic proteins (p47phox, p67phox, Rac, and p40phox). Upon stimulation, the cytosolic components translocate to the membrane, as the result of a series of interactions among the cytosolic components and among the cytosolic components and cytochrome b559 and its phospholipid environment. We described the construction of a tripartite chimera (trimera) consisting of strategic domains of p47phox, p67phox, and Rac1, in which interactions among cytosolic components were replaced by fusion (Berdichevsky, Y., Mizrahi, A., Ugolev, Y., Molshanski-Mor, S., and Pick, E. (2007) J. Biol. Chem. 282, 22122–22139). We now fused green fluorescent protein (GFP) to the N terminus of the trimera and found the following. 1) The GFP-p47phox-p67phox-Rac1 trimera activates the oxidase in amphiphile-dependent and -independent (anionic phospholipid-enriched membrane) cell-free systems. 2) Geranylgeranylation of the GFP-trimera makes it a potent oxidase activator in unmodified (native) membranes and in the absence of amphiphile. 3) Prenylated GFP-trimera binds spontaneously to native membranes (as assessed by gel filtration and in-line fluorometry), forming a tight complex capable of NADPH-dependent, activator-independent superoxide production at rates similar to those measured in canonical cell-free systems. 4) Prenylation of the GFP-trimera supersedes completely the dependence of oxidase activation on the p47phox phox homology domain and, partially, on the Rac1 polybasic domain, but the requirement for Trp193 in p47phox persists. Prenylated GFP-p47phox-p67phox-Rac1 trimera acts as a quintessential single molecule oxidase activator of potential use in high throughput screening of inhibitors. PMID:20529851
Photophysical Studies of Spin Cast Polymer Films

DTIC Science & Technology

1988-07-13

Polymeric Materials contained research presentations on fundamental radiation chemistry and physics as well as on technological applications of polymer ...on Polymeric Materials," X~os Hoos. ueensland. Australia., August 16-19, 1987 ,7 COSAII CODES I&. SUBJECT TEAMS (Conuo an itwre it r~,*Ctzy Mid od@0ty...by biOck mumblrJ _ILO GR UP SU8 -GaOUP 9. AaSTkRAC7T (COn1nue an r*"wne it noatamey and iwaf by bWok nuffltr) Snim casting is a commonly used technique
77 FR 33563 - Applications for New Awards; Comprehensive Centers Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-06

... career-ready standards and aligned, high-quality assessments for all students; (2) identifying... outcomes for all students; close achievement gaps; and improve the quality of instruction. Regional...)) established Regional Advisory Committees (RACs) and charged them with conducting educational needs assessments...
Rac1 modulates cardiomyocyte adhesion during mouse embryonic development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abu-Issa, Radwan, E-mail: rabuissa@umich.edu

2015-01-24

Highlights: • Conditional knockout of Rac1 using Nkx2.5 Cre line is lethal at E13.5. • The myocardium of the mutant is thin and disorganized. • The phenotype is not due to cardiomyocyte low proliferation or apoptosis. • The phenotype is due to specific defect in cardiomyocyte adhesion. - Abstract: Rac1, a member of the Rho subfamily of small GTPases, is involved in morphogenesis and differentiation of many cell types. Here we define a role of Rac1 in cardiac development by specifically deleting Rac1 in the pre-cardiac mesoderm using the Nkx2.5-Cre transgenic driver line. Rac1-conditional knockout embryos initiate heart development normallymore » until embryonic day 11.5 (E11.5); their cardiac mesoderm is specified, and the heart tube is formed and looped. However, by E12.5-E13.5 the mutant hearts start failing and embryos develop edema and hemorrhage which is probably the cause for the lethality observed soon after. The hearts of Rac1-cKO embryos exhibit disorganized and thin myocardial walls and defects in outflow tract alignment. No significant differences of cardiomyocyte death or proliferation were found between developing control and mutant embryos. To uncover the role of Rac1 in the heart, E11.5 primary heart cells were cultured and analyzed in vitro. Rac1-deficient cardiomyocytes were less spread, round and loosely attached to the substrate and to each other implying that Rac1-mediated signaling is required for appropriate cell–cell and/or cellmatrix adhesion during cardiac development.« less
The Transcriptomic Signature of RacA Activation and Inactivation Provides New Insights into the Morphogenetic Network of Aspergillus niger

PubMed Central

Kwon, Min Jin; Nitsche, Benjamin M.; Arentshorst, Mark; Jørgensen, Thomas R.; Ram, Arthur F. J.; Meyer, Vera

2013-01-01

RacA is the main Rho GTPase in Aspergillus niger regulating polarity maintenance via controlling actin dynamics. Both deletion and dominant activation of RacA (RacG18V) provoke an actin localization defect and thereby loss of polarized tip extension, resulting in frequent dichotomous branching in the ΔracA strain and an apolar growing phenotype for RacG18V. In the current study the transcriptomics and physiological consequences of these morphological changes were investigated and compared with the data of the morphogenetic network model for the dichotomous branching mutant ramosa-1. This integrated approach revealed that polar tip growth is most likely orchestrated by the concerted activities of phospholipid signaling, sphingolipid signaling, TORC2 signaling, calcium signaling and CWI signaling pathways. The transcriptomic signatures and the reconstructed network model for all three morphology mutants (ΔracA, RacG18V, ramosa-1) imply that these pathways become integrated to bring about different physiological adaptations including changes in sterol, zinc and amino acid metabolism and changes in ion transport and protein trafficking. Finally, the fate of exocytotic (SncA) and endocytotic (AbpA, SlaB) markers in the dichotomous branching mutant ΔracA was followed, demonstrating that hyperbranching does not per se result in increased protein secretion. PMID:23894378
A Small GTP-Binding Host Protein Is Required for Entry of Powdery Mildew Fungus into Epidermal Cells of Barley1

PubMed Central

Schultheiss, Holger; Dechert, Cornelia; Kogel, Karl-Heinz; Hückelhoven, Ralph

2002-01-01

Small GTP-binding proteins such as those from the RAC family are cytosolic signal transduction proteins that often are involved in processing of extracellular stimuli. Plant RAC proteins are implicated in regulation of plant cell architecture, secondary wall formation, meristem signaling, and defense against pathogens. We isolated a RacB homolog from barley (Hordeum vulgare) to study its role in resistance to the barley powdery mildew fungus (Blumeria graminis f.sp. hordei). RacB was constitutively expressed in the barley epidermis and its expression level was not strongly influenced by inoculation with B. graminis. However, after biolistic bombardment of barley leaf segments with RacB-double-stranded RNA, sequence-specific RNA interference with RacB function inhibited fungal haustorium establishment in a cell-autonomous and genotype-specific manner. Mutants compromised in function of the Mlo wild-type gene and the Ror1 gene (genotype mlo5 ror1) that are moderately susceptible to B. graminis showed no alteration in powdery mildew resistance upon RacB-specific RNA interference. Thus, the phenotype, induced by RacB-specific RNA interference, was apparently dependent on the same processes as mlo5-mediated broad resistance, which is suppressed by ror1. We conclude that an RAC small GTP-binding protein is required for successful fungal haustorium establishment and that this function may be linked to MLO-associated functions. PMID:11950993
The Phosphatidylinositol (3,4,5)-Trisphosphate-dependent Rac Exchanger 1·Ras-related C3 Botulinum Toxin Substrate 1 (P-Rex1·Rac1) Complex Reveals the Basis of Rac1 Activation in Breast Cancer Cells.

PubMed

Lucato, Christina M; Halls, Michelle L; Ooms, Lisa M; Liu, Heng-Jia; Mitchell, Christina A; Whisstock, James C; Ellisdon, Andrew M

2015-08-21

The P-Rex (phosphatidylinositol (3,4,5)-trisphosphate (PIP3)-dependent Rac exchanger) family (P-Rex1 and P-Rex2) of the Rho guanine nucleotide exchange factors (Rho GEFs) activate Rac GTPases to regulate cell migration, invasion, and metastasis in several human cancers. The family is unique among Rho GEFs, as their activity is regulated by the synergistic binding of PIP3 and Gβγ at the plasma membrane. However, the molecular mechanism of this family of multi-domain proteins remains unclear. We report the 1.95 Å crystal structure of the catalytic P-Rex1 DH-PH tandem domain in complex with its cognate GTPase, Rac1 (Ras-related C3 botulinum toxin substrate-1). Mutations in the P-Rex1·Rac1 interface revealed a critical role for this complex in signaling downstream of receptor tyrosine kinases and G protein-coupled receptors. The structural data indicated that the PIP3/Gβγ binding sites are on the opposite surface and markedly removed from the Rac1 interface, supporting a model whereby P-Rex1 binding to PIP3 and/or Gβγ releases inhibitory C-terminal domains to expose the Rac1 binding site. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
A comparative study on the heavy metal solidification/stabilization performance of four chemical solidifying agents in municipal solid waste incineration fly ash.

PubMed

Wang, Feng-He; Zhang, Fan; Chen, Ya-Jun; Gao, Jay; Zhao, Bin

2015-12-30

Investigated in this paper were the content, specification distribution, and risk assessment code (RAC) determination of six targeted heavy metals and potentially toxic metals in fly ashes from a municipal solid waste incinerator in China. Contained in it is a comparison of the solidification/stabilization performance of two novel solidifying agents of sixthio guanidine acid (SGA) and tetrathio bicarbamic acid (TBA) with sodium dimethyldithiocarbamate (SDD) and Na2S, and analysis of their leachability in accordance with TCLP 1311 of the US EPA and the extraction procedures of China (HJ/T 299-2007 and HJ/T300-2007). The total concentration of Zn, Cu, Ni, Pb, Cr, Cd is 37383.47, 3080.77, 1583.92, 1356.43, 566.15, and 77.83 mg/kg, respectively. Cr (3.7%) and Pb (7.50%) pose low risk; and Ni (12.93%) and Zn (15.45%) have a medium risk; while Cu (69.84%) and Cd (82.5%) have a very high risk according to their RAC score. Compared with SDD and Na2S, SGA and TBA show an excellent overall solidifying performance due to their multiply hydrosulfide groups that bind with heavy metals very efficiently. The obtained results indicate that the leaching content of Cd, Ni, Pb and Zn is higher than the thresholds prescribed in GB5085.3-2007, and the excessive acetic acid makes its binding capacity stronger in HJ/T 300-2007 than in TCLP 1311. Copyright © 2015 Elsevier B.V. All rights reserved.
Deacetylmycoepoxydiene is an agonist of Rac1, and simultaneously induces autophagy and apoptosis.

PubMed

Xie, Wei; Zhang, Wei; Sun, Mingwei; Lu, Chunhua; Shen, Yuemao

2018-05-09

Lung cancer is the second most common cause of cancer-related death in the world. Most cases of lung cancer are not curable, especially non-small cell lung cancer (NSCLC). Thus, novel treatment targets for this malignant disease are urgently needed. Here, we demonstrate the feasibility of Rac1 in treating p53-null human NSCLC H1299 as a novel drug target. Deacetylmycoepoxydiene (DA-MED), a cytotoxic natural polyketide, functions as a Rac1 agonist in p53-null NSCLC H1299 cells. DA-MED treatment drives Rac1 activation and promotes robust production of reactive oxygen species, activating mitochondrial permeability transition and the intrinsic apoptotic pathway. Knockdown of Rac1 decreases ROS production in DA-MED-treated cells, resulting in a concomitant decrease in DA-MED-induced apoptosis. DA-MED-activated Rac1 induces autophagy by inhibiting mammalian target of rapamycin, leading to anti-apoptotic and anti-metastatic effects. Therefore, this study provides novel insight into the complex cytotoxic and pro-survival mechanisms associated with a potent Rac1 agonist and suggests that further development of more potent Rac1 agonists could be an effective strategy for future non-small cell lung cancer treatments.
bFGF Regulates PI3-Kinase-Rac1-JNK Pathway and Promotes Fibroblast Migration in Wound Healing

PubMed Central

Kanazawa, Shigeyuki; Fujiwara, Toshihiro; Matsuzaki, Shinsuke; Shingaki, Kenta; Taniguchi, Manabu; Miyata, Shingo; Tohyama, Masaya; Sakai, Yasuo; Yano, Kenji; Hosokawa, Ko; Kubo, Tateki

2010-01-01

Fibroblast proliferation and migration play important roles in wound healing. bFGF is known to promote both fibroblast proliferation and migration during the process of wound healing. However, the signal transduction of bFGF-induced fibroblast migration is still unclear, because bFGF can affect both proliferation and migration. Herein, we investigated the effect of bFGF on fibroblast migration regardless of its effect on fibroblast proliferation. We noticed involvement of the small GTPases of the Rho family, PI3-kinase, and JNK. bFGF activated RhoA, Rac1, PI3-kinase, and JNK in cultured fibroblasts. Inhibition of RhoA did not block bFGF-induced fibroblast migration, whereas inhibition of Rac1, PI3-kinase, or JNK blocked the fibroblast migration significantly. PI3-kinase-inhibited cells down-regulated the activities of Rac1 and JNK, and Rac1-inhibited cells down-regulated JNK activity, suggesting that PI3-kinase is upstream of Rac1 and that JNK is downstream of Rac1. Thus, we concluded that PI3-kinase, Rac1, and JNK were essential for bFGF-induced fibroblast migration, which is a novel pathway of bFGF-induced cell migration. PMID:20808927
Elimination and Concentration Correlations between Edible Tissues and Biological Fluids and Hair of Ractopamine in Pigs and Goats Fed with Ractopamine-Medicated Feed.

PubMed

Huang, Lingli; Shi, Jingfei; Pan, Yuanhu; Wang, Liye; Chen, Dongmei; Xie, Shuyu; Liu, Zhenli; Yuan, Zonghui

2016-03-09

Ractopamine (RAC), a β-adrenergic leanness-enhancing agent, endangers the food safety of animal products because of overdosing and illegal use in food animals. Excretion and residue depletion of RAC in pigs and goats were investigated to determine a representative biological fluid or surface tissue for preslaughter monitoring. After a single oral gavage of RAC, 64-67% of the dose was excreted from the urine of pigs and goats within 12-24 h. RAC persisted the longest in the hair of pigs and goats but depleted rapidly in the plasma, muscle, and fat. Urine and hair were excellent for predicting RAC residues in edible tissues of pigs, whereas plasma and urine were satisfactory body fluids for the prediction of RAC concentrations in edible tissues of goats. These data provided a simple and economical preslaughter living monitoring method for the illegal use and violative residue of RAC in food animals.
Enantioselective Bioaccumulation and Toxicity of the Neonicotinoid Insecticide Dinotefuran in Earthworms ( Eisenia fetida).

PubMed

Liu, Tong; Chen, Dan; Li, Yiqiang; Wang, Xiuguo; Wang, Fenglong

2018-05-02

The enantioselective bioaccumulation and toxicity of dinotefuran in earthworms were studied in this study. The results showed that S-dinotefuran accumulated faster than Rac-dinotefuran and R-dinotefuran in earthworms. The acute toxicity of S-dinotefuran was 1.49 and 2.67 times that of the Rac-dinotefuran and R-dinotefuran in artificial soil during 14 days of exposure. At 1.0 mg/kg, the three tested chemicals inhibited the growth and reproduction as well as induced oxidative stress effects in earthworms; however, the toxic effects induced by S-dinotefuran were the most serious. The transcriptome sequencing results showed that S-dinotefuran had stronger interactions to biomacromolecules and influences on the endoplasmic reticulum (ER) than R-dinotefuran, which may be the main reason for enantioselectivities between the two enantiomers. The present results indicated that the risk of S-dinotefuran was higher than that of Rac-dinotefuran and R-dinotefuran in the soil environment to earthworms. Risk assessment of dinotefuran should be evaluated at the enantiomer level.
Relevance of small GTPase Rac1 pathway in drug and radio-resistance mechanisms: Opportunities in cancer therapeutics.

PubMed

Cardama, G A; Alonso, D F; Gonzalez, N; Maggio, J; Gomez, D E; Rolfo, C; Menna, P L

2018-04-01

Rac1 GTPase signaling pathway has a critical role in the regulation of a plethora of cellular functions governing cancer cell behavior. Recently, it has been shown a critical role of Rac1 in the emergence of resistance mechanisms to cancer therapy. This review describes the current knowledge regarding Rac1 pathway deregulation and its association with chemoresistance, radioresistance, resistance to targeted therapies and immune evasion. This supports the idea that interfering Rac1 signaling pathway could be an interesting approach to tackle cancer resistance. Copyright © 2018 Elsevier B.V. All rights reserved.
Calibration between the Estimated Probability of the Risk Assessment Chart of Japan Atherosclerosis Society and Actual Mortality Using External Population: Evidence for Cardiovascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN).

PubMed

Nakai, Michikazu; Miyamoto, Yoshihiro; Higashiyama, Aya; Murakami, Yoshitaka; Nishimura, Kunihiro; Yatsuya, Hiroshi; Saitoh, Shigeyuki; Sakata, Kiyomi; Iso, Hiroyasu; Miura, Katsuyuki; Ueshima, Hirotsugu; Okamura, Tomonori

2016-01-01

In Japan Atherosclerosis Society guidelines for the prevention of atherosclerotic cardiovascular diseases 2012 (JAS2012), NIPPON DATA80 risk assessment chart (ND80RAC) was adopted to estimate the 10-year probability of coronary artery disease (CAD) mortality. However, there was no comparison between the estimated mortality calculated by ND80RAC and actual mortality in external populations. Accordingly, we used the large pooled database of cohorts in Japan, EPOCH-JAPAN, as an external population. The participants of EPOCH-JAPAN without a history of cardiovascular disease (15,091 men and 18,589 women aged 40-74 years) were analyzed based on sex. The probability of a 10-year risk of CAD/stroke mortality was estimated by ND80RAC. The participants were divided into both decile of their estimated mortality and three categories according to JAS2012. The calibration between the mean estimated mortality and the actual mortality was performed by the Hosmer and Lemeshow (H-L) test. In both sexes, the estimated CAD mortality was higher than the actual mortality, particularly in higher deciles of estimated mortality, and the estimated stroke mortality was almost concordant with the actual mortality in low/moderate deciles of estimated mortality. As for the categories according to JAS2012, the estimated CAD mortality was higher than the actual mortality in both sexes; actual mortality in Category III was lower than that in Category II in women. However, it increased in the ascending order of category when we excluded the presence of diabetes from Category III. The estimated CAD mortality by ND80RAC tended to be higher than the actual mortality in the population in which the baseline survey was more recently performed.
Interaction effects and mechanism of Pb pollution and soil microorganism in the presence of earthworm.

PubMed

Liu, Gao; Ling, Siyuan; Zhan, Xiuping; Lin, Zhifen; Zhang, Wei; Lin, Kuangfei

2017-04-01

Heavy metals usually cause great damage to soil ecosystem. Lead (Pb) was chosen as a research object in the present study. Here repeated exposure of Pb was designed for the soil artificially contaminated. A laboratory study was conducted to determine the changes in the Pb availability and biological activity in the presence of earthworm, and the risk assessment code (RAC) was applied to evaluate the remediated soil. Results demonstrated that Pb gradually transformed to more stable fractions (OMB- and FeMnOX-Pb) under microbial action, indicating the risk level of Pb was declined. On the other hand, Pb also caused the inhibition of soil respiration and microbial biomass, and the higher the concentration of Pb, the stronger the inhibition; While in the presence of earthworm, it could absorb Pb and facilitate microbial activity, reflected the decrease of Pb content and the increase of respiration intensity in soil, as well as microbial biomass. Additionally, a good dose-response relationship between EXCH-Pb content and respiration intensity might provide a basis for ecological risk assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.
Deficiency of Rac1 Blocks NADPH Oxidase Activation, Inhibits Endoplasmic Reticulum Stress, and Reduces Myocardial Remodeling in a Mouse Model of Type 1 Diabetes

PubMed Central

Li, Jianmin; Zhu, Huaqing; Shen, E; Wan, Li; Arnold, J. Malcolm O.; Peng, Tianqing

2010-01-01

OBJECTIVE Our recent study demonstrated that Rac1 and NADPH oxidase activation contributes to cardiomyocyte apoptosis in short-term diabetes. This study was undertaken to investigate if disruption of Rac1 and inhibition of NADPH oxidase would prevent myocardial remodeling in chronic diabetes. RESEARCH DESIGN AND METHODS Diabetes was induced by injection of streptozotocin in mice with cardiomyocyte-specific Rac1 knockout and their wild-type littermates. In a separate experiment, wild-type diabetic mice were treated with vehicle or apocynin in drinking water. Myocardial hypertrophy, fibrosis, endoplasmic reticulum (ER) stress, inflammatory response, and myocardial function were investigated after 2 months of diabetes. Isolated adult rat cardiomyocytes were cultured and stimulated with high glucose. RESULTS In diabetic hearts, NADPH oxidase activation, its subunits' expression, and reactive oxygen species production were inhibited by Rac1 knockout or apocynin treatment. Myocardial collagen deposition and cardiomyocyte cross-sectional areas were significantly increased in diabetic mice, which were accompanied by elevated expression of pro-fibrotic genes and hypertrophic genes. Deficiency of Rac1 or apocynin administration reduced myocardial fibrosis and hypertrophy, resulting in improved myocardial function. These effects were associated with a normalization of ER stress markers' expression and inflammatory response in diabetic hearts. In cultured cardiomyocytes, high glucose–induced ER stress was inhibited by blocking Rac1 or NADPH oxidase. CONCLUSIONS Rac1 via NADPH oxidase activation induces myocardial remodeling and dysfunction in diabetic mice. The role of Rac1 signaling may be associated with ER stress and inflammation. Thus, targeting inhibition of Rac1 and NADPH oxidase may be a therapeutic approach for diabetic cardiomyopathy. PMID:20522592
Identification of Best Practices for Resident Aesthetic Clinics in Plastic Surgery Training: The ACAPS National Survey

PubMed Central

Wu, Cindy; Bentz, Michael L.; Redett, Richard J.; Shack, R. Bruce; David, Lisa R.; Taub, Peter J.; Janis, Jeffrey E.

2015-01-01

Introduction: Resident aesthetic clinics (RACs) have demonstrated good outcomes and acceptable patient satisfaction, but few studies have evaluated their educational, financial, or medicolegal components. We sought to determine RAC best practices. Methods: We surveyed American Council of Academic Plastic Surgeon members (n = 399), focusing on operational details, resident supervision, patient safety, medicolegal history, financial viability, and research opportunities. Of the 96 respondents, 63 reported having a RAC, and 56% of plastic surgery residency program directors responded. Results: RACs averaged 243 patient encounters and 53.9 procedures annually, having been in existence for 19.6 years (mean). Full-time faculty (73%) supervised chief residents (84%) in all aspects of care (65%). Of the 63 RACs, 45 were accredited, 40 had licensed procedural suites, 28 had inclusion/exclusion criteria, and 31 used anesthesiologists. Seventeen had overnight capability, and 17 had a Life Safety Plan. No cases of malignant hyperthermia occurred, but 1 facility death was reported. Sixteen RACs had been involved in a lawsuit, and 33 respondents reported financial viability of the RACs. Net revenue was transferred to both the residents’ educational fund (41%) and divisional/departmental overhead (37%). Quality measures included case logs (78%), morbidity/mortality conference (62%), resident surveys (52%), and patient satisfaction scores (46%). Of 63 respondents, 14 have presented or published RAC-specific research; 80 of 96 of those who were surveyed believed RACs enhanced education. Conclusions: RACs are an important component of plastic surgery education. Most clinics are financially viable but carry high malpractice risk and consume significant resources. Best practices, to maximize patient safety and optimize resident education, include use of accredited procedural rooms and direct faculty supervision of all components of care. PMID:26146599
Rac1 GTPase -deficient mouse lens exhibits defects in shape, suture formation, fiber cell migration and survival

PubMed Central

Maddala, Rupalatha; Chauhan, Bharesh K.; Walker, Christopher; Zheng, Yi; Robinson, Michael L.; Lang, Richard A.; Rao, Ponugoti V.

2011-01-01

Morphogenesis and shape of the ocular lens depend on epithelial cell elongation and differentiation into fiber cells, followed by the symmetric and compact organization of fiber cells within an enclosed extracellular matrix-enriched elastic capsule. The cellular mechanisms orchestrating these different events however, remain obscure. We investigated the role of the Rac1 GTPase in these processes by targeted deletion of expression using the conditional gene knockout (cKO) approach. Rac1 cKO mice were derived from two different Cre (Le-Cre and MLR-10) transgenic mice in which lens-specific Cre expression starts at embryonic day 8.75 and 10.5, respectively, in both the lens epithelium and fiber cells. The Le-Cre/Rac1 cKO mice exhibited an early-onset (E12.5) and severe lens phenotype compared to the MLR-10/Rac1 cKO (E15.5) mice. While the Le-Cre/Rac1 cKO lenses displayed delayed primary fiber cell elongation, lenses from both Rac1 cKO strains were characterized by abnormal shape, impaired secondary fiber cell migration, sutural defects and thinning of the posterior capsule which often led to rupture. Lens fiber cell N-cadherin/β-catenin/Rap1/Nectin-based cell-cell junction formation and WAVE-2/Abi-2/Nap1-regulated actin polymerization were impaired in the Rac1 deficient mice. Additionally, the Rac1 cKO lenses were characterized by a shortened epithelial sheet, reduced levels of extracellular matrix (ECM) proteins and increased apoptosis. Taken together, these data uncover the essential role of Rac1 GTPase activity in establishment and maintenance of lens shape, suture formation and capsule integrity, and in fiber cell migration, adhesion and survival, via regulation of actin cytoskeletal dynamics, cell adhesive interactions and ECM turnover. PMID:21945075
75 FR 27703 - Humboldt Resource Advisory Committee (RAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-18

... Community Self-Determination Act (Pub. L. 110- 343) and in compliance with the Federal Advisory Committee... Federal Official and RAC Coordinator roles; (5) selection of RAC Chair; (6) next meeting agenda, location...
Effects of different frequencies of rhythmic auditory cueing on the stride length, cadence, and gait speed in healthy young females.

PubMed

Yu, Lili; Zhang, Qi; Hu, Chunying; Huang, Qiuchen; Ye, Miao; Li, Desheng

2015-02-01

[Purpose] The aim of this study was to explore the effects of different frequencies of rhythmic auditory cueing (RAC) on stride length, cadence, and gait speed in healthy young females. The findings of this study might be used as clinical guidance of physical therapy for choosing the suitable frequency of RAC. [Subjects] Thirteen healthy young females were recruited in this study. [Methods] Ten meters walking tests were measured in all subjects under 4 conditions with each repeated 3 times and a 3-min seated rest period between repetitions. Subjects first walked as usual and then were asked to listen carefully to the rhythm of a metronome and walk with 3 kinds of RAC (90%, 100%, and 110% of the mean cadence). The three frequencies (90%, 100%, and 110%) of RAC were randomly assigned. Gait speed, stride length, and cadence were calculated, and a statistical analysis was performed using the SPSS (version 17.0) computer package. [Results] The gait speed and cadence of 90% RAC walking showed significant decreases compared with normal walking and 100% and 110% RAC walking. The stride length, cadence, and gait speed of 110% RAC walking showed significant increases compared with normal walking and 90% and 100% RAC walking. [Conclusion] Our results showed that 110% RAC was the best of the 3 cueing frequencies for improvement of stride length, cadence, and gait speed in healthy young females.

Characterisation of the Rac/PAK pathway in Amoeba proteus.

PubMed

Kłopocka, W; Moraczewska, J; Redowicz, M J

2005-04-01

Molecular mechanisms underlying the unique locomotion of the highly motile Amoeba proteus still remain poorly understood. Recently, we have shown that blocking the endogenous amoebal Rac-like protein(s) leads to distinct and irreversible changes in the appearance of these large migrating cells as well as to a significant inhibition of their locomotion. To elucidate the mechanism of the Rac pathway in Amoeba proteus, we tested the effects of blocking the endogenous myosin I heavy chain kinase (MIHCK), one of the Rac effectors in Acanthamoeba castellanii and Dictyostelium discoideum, with anti-MIHCK antibodies in migrating amoebae, as well as the effect of inhibiting Rac and MIHCK on the actin polymerisation process. Antibodies against A. castellanii MIHCK detected an A. proteus protein with a molecular mass (ca. 95 kDa) similar to the A. castellanii kinase. The cellular distribution of MIHCK in A. proteus was very similar to those of Rac-like protein in amoebae and MIHCK in A. castellanii. Amoebae microinjected with anti-MIHCK antibodies moved slower and protruded fewer wide pseudopodia (5-6) than the control cells (9-10), resembling to some extent the phenotype of cells microinjected with anti-Rac antibodies. The in vitro studies indicate that the A. proteus Rac-like protein, but not the MIHCK isoform, is engaged in the regulation of the nucleation step of the actin polymerisation process. These observations suggest that MIHCK may be one of the effectors for Rac in these extremely large cells.
Impact of error self-perception of aerobic capacity in the safety and efficacy of the lifeguards.

PubMed

Prieto, Jose A; Nistal, Paloma; Méndez, David; Abelairas-Gomez, Cristian; Barcala-Furelos, Roberto

2016-01-01

The strong physical demands that are required of lifeguards during rescues also require an accurate self-perception of one's fitness level to be able to regulate the intensity of effort. The aim of this study was to determine the real aerobic capacity (RAC) and to compare it with two self-reported measurements: subjective appraisal of aerobic capacity (SAAC) and appraisal of physical exercise (APE). Fifty-two professional lifeguards were included in the study. For an objective assessment of RAC, the lifeguards' maximum oxygen uptake (VO2max) values were measured during treadmill stress tests. A fitness assessment questionnaire was used to obtain the SAAC and APE values. We found a statistically significant association between the APE and RAC variables in the contingency analysis (p < 0.001). In total, 93.7% of the lifeguards who obtained a VO2max value below 43 ml kg(-1) min(-1) considered their aerobic capacity to be high or very high. This self-perception error of true aerobic capacity could lead to premature fatigue during a rescue, endangering both the lifeguard's life and the life of the victim. These data may help lifeguards and beach managers to become aware of the need to know lifeguards' true physical conditions through testing and structured training programs.
Accelerating Improvements in the Energy Efficiency of Room Air Conditioners (RACs) in India: Potential, Cost-Benefit, and Policies (Interim Assessment)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abhyankar, Nikit; Shah, Nihar; Park, Won Young

Falling AC prices, increasing incomes, increasing urbanization, and high cooling requirements due to hot climate are all driving increasing uptake of Room Air Conditioners (RACs) in the Indian market. Air conditioning already comprises 40-60% of summer peak load in large metropolitan Indian cities such as Delhi and is likely to contribute 150 GW to the peak demand in 2030. Standards and labeling policies have contributed to improving the efficiency of RACs in India by about 2.5% in the last 10 years (2.5% per year) while inflation adjusted RAC prices have continued to decline. In this paper, we assess the technicalmore » feasibility, cost-benefit, and required policy enhancements by further accelerating the efficiency improvement of RACs in India. We find that there are examples of significantly more accelerated improvements such as those in Japan and Korea where AC efficiency improved by more than 7% per year resulting in almost a doubling of energy efficiency in 7 to 10 years while inflation adjusted AC prices continued to decline. We find that the most efficient RAC sold on the Indian market is almost twice as efficient as the typical AC sold on the market and hence see no technology constraints in a similar acceleration of improvement of efficiency. If starting 2018, AC efficiency improves at a rate of 6% instead of 3%, 40-60 GW of peak load (equivalent to connected load of 5-6 billion LED bulbs), and over 75 TWh/yr (equivalent to 60 million consumers consuming 100 kWh/month) will be saved by 2030; total peak load reduction would be as high as 50 GW. The net present value (NPV) of the consumer benefit between 2018-2030 will range from Rs 18,000 Cr in the most conservative case (in which prices don’t continue to decline and increase based estimates of today’s cost of efficiency improvement) to 140,000 Cr in a more realistic case (in which prices are not affected by accelerated efficiency improvement as shown by historical experience). This benefit is achievable by ratcheting up the 1 star level for fixed and inverter ACs to the level of today’s five star rating for inverter ACs by 2022. Bulk procurement (similar to the Domestic Efficient Lighting Program) and incentive programs can complement the accelerated ratcheting up of star levels. Similar programs can also be implemented for other types of ACs.« less
On the security of semi-device-independent QKD protocols

NASA Astrophysics Data System (ADS)

Chaturvedi, Anubhav; Ray, Maharshi; Veynar, Ryszard; Pawłowski, Marcin

2018-06-01

While fully device-independent security in (BB84-like) prepare-and-measure quantum key distribution (QKD) is impossible, it can be guaranteed against individual attacks in a semi-device-independent (SDI) scenario, wherein no assumptions are made on the characteristics of the hardware used except for an upper bound on the dimension of the communicated system. Studying security under such minimal assumptions is especially relevant in the context of the recent quantum hacking attacks wherein the eavesdroppers can not only construct the devices used by the communicating parties but are also able to remotely alter their behavior. In this work, we study the security of a SDIQKD protocol based on the prepare-and-measure quantum implementation of a well-known cryptographic primitive, the random access code (RAC). We consider imperfect detectors and establish the critical values of the security parameters (the observed success probability of the RAC and the detection efficiency) required for guaranteeing security against eavesdroppers with and without quantum memory. Furthermore, we suggest a minimal characterization of the preparation device in order to lower the requirements for establishing a secure key.
77 FR 46682 - Trinity County Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-06

... Rural Schools one-year extension to the 2008-2011 RAC authorization, and recruitment of new RAC..., overview of one-year extension, and new RAC committee member recruitment. An agenda of the meeting is also...
Epidermal growth factor-induced mobilization of a ganglioside-specific sialidase (NEU3) to membrane ruffles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamaguchi, Kazunori; Hata, Keiko; Wada, Tadashi

2006-07-28

Human ganglioside-specific sialidase, NEU3, localized at cell membranes is thought to regulate various biological processes at cell surfaces. We here explored functional subcellular localization of the sialidase by immunofluorescence and found accumulation at leading edges of cell membranes in the presence of serum in culture. In response to EGF, the sialidase redistributed rapidly to ruffling cell membranes of squamous carcinoma A431 cells and co-localized with Rac-1. NEU3 overexpression enhanced Rac-1 activation and cell migration as compared with controls in HeLa cells as well as in A431 cells. Consistent with co-localization with Rac-1 by immunofluorescence, NEU3 was found to co-precipitate withmore » activated Rac bound to GST-PAK-1 fusion protein. NEU3 silencing by siRNA, in contrast, resulted in inhibition of Rac-1 activation. These results indicate that NEU3 is able to mobilize to membrane ruffles in response to growth stimuli and activate the Rac-1 signaling by co-localization with Rac-1, leading to increased cell motility.« less
Effect of ractopamine-HCl supplementation for 28 days on carcass characteristics, muscle fiber morphometrics, and whole muscle yields of six distinct muscles of the loin and round.

PubMed

Gonzalez, J M; Johnson, S E; Stelzleni, A M; Thrift, T A; Savell, J D; Warnock, T M; Johnson, D D

2010-07-01

This study evaluated the effects of ractopamine-HCl (RAC) supplementation on carcass characteristics, muscle fiber morphometrics, and tenderness. Thirty-four steers (2 groups, 4 replicates) were fed RAC or carrier for 28 days prior to harvest. Seventy-two hours postmortem, the Longissimus lumborum (LL), Gracilis (GRA), Vastus lateralis (VL), Rectus femoris (RF), Semimembranosus (SM), and Adductor (ADD) were dissected from each carcass. Commodity weight, denuded weight, and muscle dimensions were collected. RAC supplementation tended to affect dressing percentage (P=0.15) and muscle firmness (P<0.15), and significantly affected lean maturity (P<0.05) and marbling score (P<0.05). With the exception of the LL and GRA (P<0.05), RAC had no effect on muscle dimensions. RAC did not influence the tenderness of vacuum-packaged, aged steaks as measured by Warner-Bratzler shear force. Muscle fiber size within the six muscles was unchanged (P>0.05) by RAC. Thus, RAC improves carcass parameters without a negative impact on tenderness. Copyright 2010 Elsevier Ltd. All rights reserved.
Sedimentological Investigations of the Martian Surface using the Mars 2001 Robotic Arm Camera and MECA Optical Microscope

NASA Technical Reports Server (NTRS)

Rice, J. W., Jr.; Smith, P. H.; Marshall, J. R.

1999-01-01

The first microscopic sedimentological studies of the Martian surface will commence with the landing of the Mars Polar Lander (MPL) December 3, 1999. The Robotic Arm Camera (RAC) has a resolution of 25 um/p which will permit detailed micromorphological analysis of surface and subsurface materials. The Robotic Ann will be able to dig up to 50 cm below the surface. The walls of the trench will also be inspected by RAC to look for evidence of stratigraphic and / or sedimentological relationships. The 2001 Mars Lander will build upon and expand the sedimentological research begun by the RAC on MPL. This will be accomplished by: (1) Macroscopic (dm to cm): Descent Imager, Pancam, RAC; (2) Microscopic (mm to um RAC, MECA Optical Microscope (Figure 2), AFM This paper will focus on investigations that can be conducted by the RAC and MECA Optical Microscope.
RAC1 GTP-ase signals Wnt-beta-catenin pathway mediated integrin-directed metastasis-associated tumor cell phenotypes in triple negative breast cancers.

PubMed

De, Pradip; Carlson, Jennifer H; Jepperson, Tyler; Willis, Scooter; Leyland-Jones, Brian; Dey, Nandini

2017-01-10

The acquisition of integrin-directed metastasis-associated (ID-MA) phenotypes by Triple-Negative Breast Cancer (TNBC) cells is caused by an upregulation of the Wnt-beta-catenin pathway (WP). We reported that WP is one of the salient genetic features of TNBC. RAC-GTPases, small G-proteins which transduce signals from cell surface proteins including integrins, have been implicated in tumorigenesis and metastasis by their role in essential cellular functions like motility. The collective percentage of alteration(s) in RAC1 in ER+ve BC was lower as compared to ER-ve BC (35% vs 57%) (brca/tcga/pub2015). High expression of RAC1 was associated with poor outcome for RFS with HR=1.48 [CI: 1.15-1.9] p=0.0019 in the Hungarian ER-veBC cohort. Here we examined how WP signals are transduced via RAC1 in the context of ID-MA phenotypes in TNBC. Using pharmacological agents (sulindac sulfide), genetic tools (beta-catenin siRNA), WP modulators (Wnt-C59, XAV939), RAC1 inhibitors (NSC23766, W56) and WP stimulations (LWnt3ACM, Wnt3A recombinant) in a panel of 6-7 TNBC cell lines, we studied fibronectin-directed (1) migration, (2) matrigel invasion, (3) RAC1 and Cdc42 activation, (4) actin dynamics (confocal microscopy) and (5) podia-parameters. An attenuation of WP, which (a) decreased cellular levels of beta-catenin, as well as its nuclear active-form, (b) decreased fibronectin-induced migration, (c) decreased invasion, (d) altered actin dynamics and (e) decreased podia-parameters was successful in blocking fibronectin-mediated RAC1/Cdc42 activity. Both Wnt-antagonists and RAC1 inhibitors blocked fibronectin-induced RAC1 activation and inhibited the fibronectin-induced ID-MA phenotypes following specific WP stimulation by LWnt3ACM as well as Wnt3A recombinant protein. To test a direct involvement of RAC1-activation in WP-mediated ID-MA phenotypes, we stimulated brain-metastasis specific MDA-MB231BR cells with LWnt3ACM. LWnt3ACM-stimulated fibronectin-directed migration was blocked by RAC1 inhibition in MDA-MB231BR cells. In the light of our previous report that WP upregulation causes ID-MA phenotypes in TNBC tumor cells, here we provide the first mechanism based evidence to demonstrate that WP upregulation signals ID-MA tumor cell phenotypes in a RAC1-GTPase dependent manner involving exchange-factors like TIAM1 and VAV2. Our study demonstrates for the first time that beta-catenin-RAC1 cascade signals integrin-directed metastasis-associated tumor cell phenotypes in TNBC.
Rac Regulates Giardia lamblia Encystation by Coordinating Cyst Wall Protein Trafficking and Secretion.

PubMed

Krtková, Jana; Thomas, Elizabeth B; Alas, Germain C M; Schraner, Elisabeth M; Behjatnia, Habib R; Hehl, Adrian B; Paredez, Alexander R

2016-08-23

Encystation of the common intestinal parasite Giardia lamblia involves the production, trafficking, and secretion of cyst wall material (CWM). However, the molecular mechanism responsible for the regulation of these sequential processes remains elusive. Here, we examined the role of GlRac, Giardia's sole Rho family GTPase, in the regulation of endomembrane organization and cyst wall protein (CWP) trafficking. Localization studies indicated that GlRac is associated with the endoplasmic reticulum (ER) and the Golgi apparatus-like encystation-specific vesicles (ESVs). Constitutive GlRac signaling increased levels of the ER marker PDI2, induced ER swelling, reduced overall CWP1 production, and promoted the early maturation of ESVs. Quantitative analysis of cells expressing constitutively active hemagglutinin (HA)-tagged GlRac (HA-Rac(CA)) revealed fewer but larger ESVs than control cells. Consistent with the phenotype of premature maturation of ESVs in HA-Rac(CA)-expressing cells, constitutive GlRac signaling resulted in increased CWP1 secretion and, conversely, morpholino depletion of GlRac blocked CWP1 secretion. Wild-type cells unexpectedly secreted large quantities of CWP1 into the medium, and free CWP1 was used cooperatively during cyst formation. These results, in part, could account for the previously reported observation that G. lamblia encysts more efficiently at high cell densities. These studies of GlRac show that it regulates encystation at several levels, and our findings support its coordinating role as a regulator of CWP trafficking and secretion. The central role of GlRac in regulating membrane trafficking and the cytoskeleton, both of which are essential to Giardia parasitism, further suggests its potential as a novel target for drug development to treat giardiasis. The encystation process is crucial for the transmission of giardiasis and the life cycle of many protists. Encystation for Giardia lamblia involves the assembly of a protective cyst wall via sequential production, trafficking, and secretion of cyst wall material. However, the regulatory pathways that coordinate cargo maturation and secretion remain unknown. Here, we asked whether the signaling activities of G. lamblia's single Rho family GTPase, GlRac, might have a regulatory role in the encystation process. We show that GlRac localizes to endomembranes and its signaling activities regulate the production of cyst wall protein 1 (CWP1), the maturation of encystation-specific vesicles (ESVs), and secretion of CWP1. We also show that secreted CWP1 is available for the development of cysts at the population level, a finding that in part could explain why Giardia encystation proceeds more efficiently at high cell densities. Copyright © 2016 Krtková et al.
Characterization and environmental risk assessment of heavy metals found in fly ashes from waste filter bags obtained from a Chinese steel plant.

PubMed

Zhou, Yun; Ning, Xun-an; Liao, Xikai; Lin, Meiqing; Liu, Jingyong; Wang, Jianghui

2013-09-01

The environmental risk of exposure to six heavy metals (Cu, Pb, Zn, Cr, Ni, and Cd) found in fly ashes from waste filter bags obtained from a steel plant was estimated based on the mineralogical compositions, total concentrations and speciation of the metals in the fly ashes. The results indicated that the fly ashes mainly consisted of hematite, magnetite, cyanite, spinel, coesite and amorphous materials. The concentrations of Zn and Pb were much higher than that of other materials. After Zn and Pb, Ni was present in the highest concentration, followed by Cu, Cr and Cd. Each heavy metal was distributed differently in fly ashes. The levels of Zn, Cd and Pb in the active fraction were very high, and ranged from 64.83 to 81.96%, 34.48 to 82.4% and 6.92 to 79.65% respectively, while Cu, Cr and Ni were mainly present in the residual fraction. The risk assessment code (RAC) values of fly ashes showed that the Zn and Cd present in the H3 sample presented a very high risk, with RAC values greater than 50%. The Cu present in the H3 sample, Cd in the H2 sample and Zn in the H4 and H5 samples presented a high risk. The Pb present in the H2 sample, Cd in the H4 sample, Ni in the H1 and H5 samples, and Zn in the H1 sample presented a medium risk. A low risk was presented by the Cu present in the H1, H2, H4 and H5 samples, the Pb in the H1, H3 and H5 samples, the Cd in the H1 and H5 samples, and the Ni in the H2 sample. No risk was presented by Cr in any sample. Copyright © 2013 Elsevier Inc. All rights reserved.
B1-control receive array coil (B-RAC) for reducing B1+ inhomogeneity in abdominal imaging at 3T-MRI

NASA Astrophysics Data System (ADS)

Kaneko, Yukio; Soutome, Yoshihisa; Habara, Hideta; Bito, Yoshitaka; Ochi, Hisaaki

2018-02-01

B1+ inhomogeneity in the human body increases as the nuclear magnetic resonance (NMR) frequency increases. Various methods have thus been developed to reduce B1+ inhomogeneity, such as a dielectric pad, a coupling coil, parallel transmit, and radio-frequency (RF) shimming. However, B1+ inhomogeneity still remains in some cases of abdominal imaging. In this study, we developed a B1-control receive array coil (B-RAC). Unlike the conventional receive array coil, B-RAC reduces B1+ inhomogeneity by using additional PIN diodes to generate the inductive loop during the RF transmit period. The inductive loop can generate dense and sparse regions of the magnetic flux, which can be used to compensate for B1+ inhomogeneity. First, B-RAC is modeled in the numerical simulation, and the spatial distributions of B1+ in a phantom and a human model were analyzed. Next, we fabricated a 12-channel B-RAC and measured receive sensitivity and B1+ maps in a 3T-MRI experiment. It was demonstrated that B-RAC can reduce B1+ inhomogeneity in the phantom and human model without increasing the maximum local specific absorption rate (SAR) in the body. B-RAC was also found to have almost the same the receive sensitivity as the conventional receive coil. Using RF shimming combined with B-RAC was revealed to more effectively reduce B1+ inhomogeneity than using only RF shimming. Therefore, B-RAC can reduce B1+ inhomogeneity while maintaining the receive sensitivity.
Distinct Effects of Rac1 on Differentiation of Primary Avian Myoblasts

PubMed Central

Gallo, Rita; Serafini, Marco; Castellani, Loriana; Falcone, Germana; Alemà, Stefano

1999-01-01

Rho family GTPases have been implicated in the regulation of the actin cytoskeleton in response to extracellular cues and in the transduction of signals from the membrane to the nucleus. Their role in development and cell differentiation, however, is little understood. Here we show that the transient expression of constitutively active Rac1 and Cdc42 in unestablished avian myoblasts is sufficient to cause inhibition of myogenin expression and block of the transition to the myocyte compartment, whereas activated RhoA affects myogenic differentiation only marginally. Activation of c-Jun N-terminal kinase (JNK) appears not to be essential for block of differentiation because, although Rac1 and Cdc42 GTPases modestly activate JNK in quail myoblasts, a Rac1 mutant defective for JNK activation can still inhibit myogenic differentiation. Stable expression of active Rac1, attained by infection with a recombinant retrovirus, is permissive for terminal differentiation, but the resulting myotubes accumulate severely reduced levels of muscle-specific proteins. This inhibition is the consequence of posttranscriptional events and suggests the presence of a novel level of regulation of myogenesis. We also show that myotubes expressing constitutively active Rac1 fail to assemble ordered sarcomeres. Conversely, a dominant-negative Rac1 variant accelerates sarcomere maturation and inhibits v-Src–induced selective disassembly of I-Z-I complexes. Collectively, our findings provide a role for Rac1 during skeletal muscle differentiation and strongly suggest that Rac1 is required downstream of v-Src in the signaling pathways responsible for the dismantling of tissue-specific supramolecular structures. PMID:10512856
Antinociceptive Effect of Racemic Flurbiprofen and Caffeine Co-Administration in an Arthritic Gout-Type Pain in Rats.

PubMed

Liévano-Reyes, Ricardo; Pérez-Méndez, Hermínia Ines; Solís-Oba, Aida; Jaramillo-Morales, Osmar Antonio; Espinosa-Juárez, Josué Vidal; López-Muñoz, Francisco Javier

2016-06-01

Preclinical Research Drug combinations are routinely used in the treatment of pain. In drug associations, adjuvants such as caffeine, are employed with different non-steroidal anti-inflammatories drugs (NSAIDs), however, at present does not exist studies showing the effect of the combination of racemic flurbiprofen (rac-Flur) in association with caffeine. The objective of this work was to evaluate the combination of rac-Flur + caffeine oral in arthritic gout-type pain in rats. The antinociceptive effects of the rac-Flur alone and in combination with caffeine were analyzed on a pain-induced functional impairment model in rat. rac-Flur induced a dose-dependent antinociceptive effect and caffeine did not present any effect. The combination of rac-Flur and caffeine achieve a higher percentage of antinociceptive effect compared with the individual administration of rac-Flur. The dose-response curve (DRCs) shows that the combination of rac-Flur (31.6 mg/kg) + caffeine (17.8 mg/kg) exhibited the maximal antinociceptive efficacy (294.0 ± 21.2 area units), while rac-Flur alone (31.6 mg/kg) showed 207.2 ± 35.2 au, thus indicating an increase in efficacy (potentiation). Furthermore, the DRCs of the combinations presented a displacement to the left, indicating a change in the potency. Caffeine is able to increase the effect of rac-Flur in the arthritic gout-type pain in rats. Drug Dev Res 77 : 192-198, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Cigarette smoke-induced alveolar epithelial-mesenchymal transition is mediated by Rac1 activation.

PubMed

Shen, Hui-juan; Sun, Yan-hong; Zhang, Shui-juan; Jiang, Jun-xia; Dong, Xin-wei; Jia, Yong-liang; Shen, Jian; Guan, Yan; Zhang, Lin-hui; Li, Fen-fen; Lin, Xi-xi; Wu, Xi-mei; Xie, Qiang-min; Yan, Xiao-feng

2014-06-01

Epithelial-mesenchymal transition (EMT) is the major pathophysiological process in lung fibrosis observed in chronic obstructive pulmonary disease (COPD) and lung cancer. Smoking is a risk factor for developing EMT, yet the mechanism remains largely unknown. In this study, we investigated the role of Rac1 in cigarette smoke (CS) induced EMT. EMT was induced in mice and pulmonary epithelial cells by exposure of CS and cigarette smoke extract (CSE) respectively. Treatment of pulmonary epithelial cells with CSE elevated Rac1 expression associated with increased TGF-β1 release. Blocking TGF-β pathway restrained CSE-induced changes in EMT-related markers. Pharmacological inhibition or knockdown of Rac1 decreased the CSE exposure induced TGF-β1 release and ameliorated CSE-induced EMT. In CS-exposed mice, pharmacological inhibition of Rac1 reduced TGF-β1 release and prevented aberrations in expression of EMT markers, suggesting that Rac1 is a critical signaling molecule for induction of CS-stimulated EMT. Furthermore, Rac1 inhibition or knockdown abrogated CSE-induced Smad2 and Akt (PKB, protein kinase B) activation in pulmonary epithelial cells. Inhibition of Smad2, PI3K (phosphatidylinositol 3-kinase) or Akt suppressed CSE-induced changes in epithelial and mesenchymal marker expression. Altogether, these data suggest that CS initiates EMT through Rac1/Smad2 and Rac1/PI3K/Akt signaling pathway. Our data provide new insights into the fundamental basis of EMT and suggest a possible new course of therapy for COPD and lung cancer. Copyright © 2014 Elsevier B.V. All rights reserved.
Effects of aging and oxidation of palladized iron embedded in activated carbon on the dechlorination of 2-chlorobiphenyl

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyeok Choi; Souhail R. Al-Abed; Shirish Agarwal

2009-06-15

Reactive activated carbon (RAC) impregnated with palladized iron has been developed to effectively treat polychlorinated biphenyls (PCBs) in the environment by coupling adsorption and dechlorination of PCBs. In this study, we addressed the dechlorination reactivity and capacity of RAC toward aqueous 2-chlorobiphenyl (2-ClBP), and its aging and longevity under various oxidizing environments. RAC containing 14.4% Fe and 0.68% Pd used in this study could adsorb 122.6 mg 2-ClBP/g RAC, and dechlorinate 56.5 mg 2-ClBP/g RAC which corresponds to 12% (yield) of its estimated dechlorination capacity. Due to Fe0 oxidation to form oxide passivating layers, Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} (oxide-watermore » interface) and FeOOH/FeO (oxide-metal interface), RAC reactivity decreased progressively over aging under N{sub 2} < H{sub 2}O + N{sub 2} < H{sub 2}O + O{sub 2} conditions. Considering nanoscale Fe/Pd corrosion chemistry, the decline was quite slow at only 5.6%, 19.5%, and 32.5% over one year, respectively. Dissolved oxygen played a crucial role in enhancing 2-ClBP adsorption but inhibiting its dechlorination. The reactivity change could be explained with the properties of the aged RAC including surface area, Fe0 content, and Fe species. During the aging and oxidation, the RAC showed limited dissolution of Fe and Pd. Finally, implementation issues regarding application of RAC system to contaminated sites are discussed. 25 refs., 6 figs., 1 tab.« less
Divergent functions of the Rho GTPases Rac1 and Cdc42 in podocyte injury

PubMed Central

Blattner, Simone M.; Hodgin, Jeffrey B.; Nishio, Masashi; Wylie, Stephanie; Saha, Jharna; Soofi, Abdul; Vining, Courtenay; Randolph, Ann; Herbach, Nadja; Wanke, Ruediger; Atkins, Kevin B.; Kang, Hee Gyung; Henger, Anna; Brakebusch, Cord; Holzman, Lawrence B.; Kretzler, Matthias

2013-01-01

Podocytes are highly specialized epithelial cells with complex actin cytoskeletal architecture crucial for maintenance of the glomerular filtration barrier. The mammalian Rho GTPases Rac1 and Cdc42 are molecular switches that control many cellular processes, but are best known for their roles in the regulation of actin cytoskeleton dynamics. Here we employed podocyte-specific Cre-lox technology and found that mice with deletion of Rac1 display normal podocyte morphology without glomerular dysfunction well into adulthood. Using the protamine sulfate model of acute podocyte injury, podocyte-specific deletion of Rac1 prevented foot process effacement. In a long-term model of chronic hypertensive glomerular damage, however, loss of Rac1 led to an exacerbation of albuminuria and glomerulosclerosis. In contrast, mice with podocyte-specific deletion of Cdc42 had severe proteinuria, podocyte foot process effacement, and glomerulosclerosis beginning as early as 10 days of age. In addition, slit diaphragm proteins nephrin and podocin were redistributed and cofilin was de-phosphorylated. Cdc42 is necessary for the maintenance of podocyte structure and function, but Rac1 is entirely dispensable in physiologic steady state. However, Rac1 has either beneficial or deleterious effects depending on the context of podocyte impairment. Thus, our study highlights the divergent roles of Rac1 and Cdc42 function in podocyte maintenance and injury. PMID:23677246
Desmoglein 3 acting as an upstream regulator of Rho GTPases, Rac-1/Cdc42 in the regulation of actin organisation and dynamics

PubMed Central

Man Tsang, Siu; Brown, Louise; Gadmor, Hanan; Gammon, Luke; Fortune, Farida; Wheeler, Ann; Wan, Hong

2012-01-01

Desmoglein 3 (Dsg3), a member of the desmoglein sub-family, serves as an adhesion molecule in desmosomes. Our previous study showed that overexpression of human Dsg3 in several epithelial lines induces formation of membrane protrusions, a phenotype suggestive of Rho GTPase activation. Here we examined the interaction between Dsg3 and actin in detail and showed that endogenous Dsg3 colocalises and interacts with actin, particularly the junctional actin in a Rac1-dependent manner. Ablation of Rac1 activity by dominant negative Rac1 mutant (N17Rac1) or the Rac1 specific inhibitor (NSC23766) directly disrupts the interaction between Dsg3 and actin. Assembly of the junctional actin at the cell borders is accompanied with enhanced levels of Dsg3, while inhibition of Dsg3 by RNAi results in profound changes in the organisation of actin cytoskeleton. In accordance, overexpression of Dsg3 results in a remarkable increase of Rac1 and Cdc42 activities and to a lesser extent, RhoA. The enhancements in Rho GTPases are accompanied by the pronounced actin-based membrane structures such as lamellipodia and filopodia, enhanced rate of actin turnover and cell polarisation. Together, our results reveal an important novel function for Dsg3 in promoting actin dynamics through regulating Rac1 and Cdc42 activation in epithelial cells. PMID:22796473
Ibuprofen Inhibits Colitis-Induced Overexpression of Tumor-Related Rac1b1

PubMed Central

Matos, Paulo; Kotelevets, Larissa; Goncalves, Vania; Henriques, Andreia; Zerbib, Philippe; Moyer, Mary Pat; Chastre, Eric; Jordan, Peter

2013-01-01

The serrated pathway to colorectal tumor formation involves oncogenic mutations in the BRAF gene, which are sufficient for initiation of hyperplastic growth but not for tumor progression. A previous analysis of colorectal tumors revealed that overexpression of splice variant Rac1b occurs in around 80% of tumors with mutant BRAF and both events proved to cooperate in tumor cell survival. Here, we provide evidence for increased expression of Rac1b in patients with inflamed human colonic mucosa as well as following experimentally induced colitis in mice. The increase of Rac1b in the mouse model was specifically prevented by the nonsteroidal anti-inflammatory drug ibuprofen, which also inhibited Rac1b expression in cultured HT29 colorectal tumor cells through a cyclooxygenase inhibition.independent mechanism. Accordingly, the presence of ibuprofen led to a reduction of HT29 cell survival in vitro and inhibited Rac1b-dependent tumor growth of HT29 xenografts. Together, our results suggest that stromal cues, namely, inflammation, can trigger changes in Rac1b expression in the colon and identify ibuprofen as a highly specific and efficient inhibitor of Rac1b overexpression in colorectal tumors. Our data suggest that the use of ibuprofen may be beneficial in the treatment of patients with serrated colorectal tumors or with inflammatory colon syndromes. PMID:23359345
RotundRacGAP Functions with Ras during Spermatogenesis and Retinal Differentiation in Drosophila melanogaster

PubMed Central

Bergeret, Evelyne; Pignot-Paintrand, Isabelle; Guichard, Annabel; Raymond, Karine; Fauvarque, Marie-Odile; Cazemajor, Michel; Griffin-Shea, Ruth

2001-01-01

Our analysis of rotund (rn) null mutations in Drosophila melanogaster revealed that deletion of the rn locus affects both spermatid and retinal differentiation. In the male reproductive system, the absence of RnRacGAP induced small testes, empty seminal vesicles, short testicular cysts, reduced amounts of interspermatid membrane, the absence of individualization complexes, and incomplete mitochondrial condensation. Flagellar growth continued within the short rn null cysts to produce large bulbous terminations of intertwined mature flagella. Organization of the retina was also severely perturbed as evidenced by grossly misshapen ommatidia containing reduced numbers of photoreceptor and pigment cells. These morphological phenotypes were rescued by genomic rnRacGAP transgenes, demonstrating that RnRacGAP function is critical to spermatid and retinal differentiation. The testicular phenotypes were suppressed by heterozygous hypomorphic mutations in the Dras1 and drk genes, indicating cross talk between RacGAP-regulated signaling and that of the Ras pathway. The observed genetic interactions are consistent with a model in which Rac signaling is activated by Ras and negatively regulated by RnRacGAP during spermatid differentiation. RnRacGAP and Ras cross talk also operated during retinal differentiation; however, while the heterozygous hypomorphic drk mutation continued to act as a suppressor of the rn null mutation, the heterozygous hypomorphic Dras1 mutation induced novel retinal phenotypes. PMID:11509670

Removal of 2-ClBP from soil-water system using activated carbon supported nanoscale zerovalent iron.

PubMed

Zhang, Wei; Yu, Tian; Han, Xiaolin; Ying, Weichi

2016-09-01

We explored the feasibility and removal mechanism of removing 2-chlorobiphenyl (2-ClBP) from soil-water system using granular activated carbon (GAC) impregnated with nanoscale zerovalent iron (reactive activated carbon or RAC). The RAC samples were successfully synthesized by the liquid precipitation method. The mesoporous GAC based RAC with low iron content (1.32%) exhibited higher 2-ClBP removal efficiency (54.6%) in the water phase. The result of Langmuir-Hinshelwood kinetic model implied that the different molecular structures between 2-ClBP and trichloroethylene (TCE) resulted in more difference in dechlorination reaction rates on RAC than adsorption capacities. Compared to removing 2-ClBP in the water phase, RAC removed the 2-ClBP more slowly in the soil phase due to the significant external mass transfer resistance. However, in the soil phase, a better removal capacity of RAC was observed than its base GAC because the chemical dechlorination played a more important role in total removal process for 2-ClBP. This important result verified the effectiveness of RAC for removing 2-ClBP in the soil phase. Although reducing the total RAC removal rate of 2-ClBP, soil organic matter (SOM), especially the soft carbon, also served as an electron transfer medium to promote the dechlorination of 2-ClBP in the long term. Copyright © 2016. Published by Elsevier B.V.
Nestin predicts a favorable prognosis in early ampullary adenocarcinoma and functions as a promoter of metastasis in advanced cancer.

PubMed

Shan, Yan-Shen; Chen, Yi-Ling; Lai, Ming-Derg; Hsu, Hui-Ping

2015-01-01

Nestin exhibits stemness characteristics and is overexpressed in several types of cancers. Downstream signaling of nestin [cyclin-dependent kinase 5 (CDK5) and Ras-related C3 botulinum toxin substrate 1 (Rac1)] functions in cancer to modulate cellular behaviors. We studied the function of nestin in ampullary adenocarcinoma. Immunohistochemistry (IHC), reverse transcription-polymerase chain reaction, and cDNA microarray of nestin in ampullary adenocarcinoma was compared with normal duodenum. CDK5 and Rac1 were assessed by western blotting. We hypothesized that nestin/CDK5/Rac1 signaling behaves different in early and advanced cancer. We found that the presence of nestin mRNA was increased in the early stages of cancer (T2N0 or T3N0) and advanced cancer with lymph node metastasis (T4N1). A total of 102 patients were enrolled in the IHC staining. Weak nestin expression was correlated with favorable characteristics of cancer, decreased incidence of local recurrence and lower risk of recurrence within 12 months after surgery. Patients with weak nestin expression had the most favorable recurrence‑free survival rates. Patients with mild to strong nestin expression exhibited an advanced behavior of cancer and increased possibility of cancer recurrence. The reciprocal expression of nestin and RAC1 were explored using a cDNA microarray analysis in the early stages of ampullary adenocarcinoma. Increased level of CDK5 with simultaneously decreased expression of Rac1 was detected by western blotting of ampullary adenocarcinoma in patients without cancer recurrence. The activation of multiple oncogenic pathways, combined with the stemness characteristics of nestin, formed a complex network in advanced ampullary adenocarcinoma. Our study demonstrated that nestin performs a dual role in ampullary adenocarcinoma. Appropriate amount of nestin enhances CDK5 function to suppress Rac1 and excessive nestin/CDK5 participates in multiple oncogenic pathways to promote cancer invasiveness. Inhibiting nestin in patients who exhibit nestin‑overexpressed ampullary adenocarcinoma may be a method of preventing cancer recurrence.
Rac regulates vascular endothelial growth factor stimulated motility.

PubMed

Soga, N; Connolly, J O; Chellaiah, M; Kawamura, J; Hruska, K A

2001-01-01

During angiogenesis endothelial cells migrate towards a chemotactic stimulus. Understanding the mechanism of endothelial cell migration is critical to the therapeutic manipulation of angiogenesis and ultimately cancer prevention. Vascular endothelial growth factor (VEGF) is a potent chemotactic stimulus of endothelial cells during angiogenesis. The endothelial cell signal transduction pathway of VEGF represents a potential target for cancer therapy, but the mechanisms of post-receptor signal transduction including the roles of rho family GTPases in regulating the cytoskeletal effects of VEGF in endothelial cells are not understood. Here we analyze the mechanisms of cell migration in the mouse brain endothelial cell line (bEND3). Stable transfectants containing a tetracycline repressible expression vector were used to induce expression of Rac mutants. Endothelial cell haptotaxis was stimulated by constitutively active V12Rac on collagen and vitronectin coated supports, and chemotaxis was further stimulated by VEGF. Osteopontin coated supports were the most stimulatory to bEND3 haptotaxis, but VEGF was not effective in further increasing migration on osteopontin coated supports. Haptotaxis on support coated with collagen, vitronectin, and to a lesser degree osteopontin was inhibited by N17 Rac. N17 Rac expression blocked stimulation of endothelial cell chemotaxis by VEGF. As part of the chemotactic stimulation, VEGF caused a loss of actin organization at areas of cell-cell contact and increased stress fiber expression in endothelial cells which were directed towards pores in the transwell membrane. N17 Rac prevented the stimulation of cell-cell contact disruption and the stress fiber stimulation by VEGF. These data demonstrate two pathways of regulating endothelial cell motility, one in which Rac is activated by matrix/integrin stimulation and is a crucial modulator of endothelial cell haptotaxis. The other pathway, in the presence of osteopontin, is Rac independent. VEGF stimulated chemotaxis, is critically dependent on Rac activation. Osteopontin was a potent matrix activator of motility, and perhaps one explanation for the absence of a VEGF plus osteopontin effect is that osteopontin stimulated motility was inhibitory to the Rac pathway.
Inhibition of Rac1 activity induces G1/S phase arrest through the GSK3/cyclin D1 pathway in human cancer cells.

PubMed

Liu, Linna; Zhang, Hongmei; Shi, Lei; Zhang, Wenjuan; Yuan, Juanli; Chen, Xiang; Liu, Juanjuan; Zhang, Yan; Wang, Zhipeng

2014-10-01

Rac1 has been shown to regulate the cell cycle in cancer cells. Yet, the related mechanism remains unclear. Thus, the present study aimed to investigate the mechanism involved in the regulation of G1/S phase transition by Rac1 in cancer cells. Inhibition of Rac1 by inhibitor NSC23766 induced G1/S phase arrest and inhibited the proliferation of A431, SW480 and U2-OS cells. Suppression of GSK3 by shRNA partially rescued G1/S phase arrest and inhibition of proliferation. Incubation of cells with NSC23766 reduced p-AKT and inactivated p-GSK3α and p-GSK3β, increased p-cyclin D1 expression and decreased the level of cyclin D1 protein. Consequently, cyclin D1 targeting transcriptional factor E2F1 expression, which promotes G1 to S phase transition, was also reduced. In contrast, constitutive active Rac1 resulted in increased p-AKT and inactivated p-GSK3α and p-GSK3β, decreased p-cyclin D1 expression and enhanced levels of cyclin D1 and E2F1 expression. Moreover, suppression of GSK3 did not alter p-AKT or Rac1 activity, but decreased p-cyclin D1 and increased total cyclin D1 protein. However, neither Rac1 nor GSK3 inhibition altered cyclin D1 at the RNA level. Moreover, after inhibition of Rac1 or GSK3 following proteasome inhibitor MG132 treatment, cyclin D1 expression at the protein level remained constant, indicating that Rac1 and GSK3 may regulate cyclin D1 turnover through phosphorylation and degradation. Therefore, our findings suggest that inhibition of Rac1 induces cell cycle G1/S arrest in cancer cells by regulation of the GSK3/cyclin D1 pathway.
Rac1 Regulates Endometrial Secretory Function to Control Placental Development.

PubMed

Davila, Juanmahel; Laws, Mary J; Kannan, Athilakshmi; Li, Quanxi; Taylor, Robert N; Bagchi, Milan K; Bagchi, Indrani C

2015-08-01

During placenta development, a succession of complex molecular and cellular interactions between the maternal endometrium and the developing embryo ensures reproductive success. The precise mechanisms regulating this maternal-fetal crosstalk remain unknown. Our study revealed that the expression of Rac1, a member of the Rho family of GTPases, is markedly elevated in mouse decidua on days 7 and 8 of gestation. To investigate its function in the uterus, we created mice bearing a conditional deletion of the Rac1 gene in uterine stromal cells. Ablation of Rac1 did not affect the formation of the decidua but led to fetal loss in mid gestation accompanied by extensive hemorrhage. To gain insights into the molecular pathways affected by the loss of Rac1, we performed gene expression profiling which revealed that Rac1 signaling regulates the expression of Rab27b, another GTPase that plays a key role in targeting vesicular trafficking. Consequently, the Rac1-null decidual cells failed to secrete vascular endothelial growth factor A, which is a critical regulator of decidual angiogenesis, and insulin-like growth factor binding protein 4, which regulates the bioavailability of insulin-like growth factors that promote proliferation and differentiation of trophoblast cell lineages in the ectoplacental cone. The lack of secretion of these key factors by Rac1-null decidua gave rise to impaired angiogenesis and dysregulated proliferation of trophoblast cells, which in turn results in overexpansion of the trophoblast giant cell lineage and disorganized placenta development. Further experiments revealed that RAC1, the human ortholog of Rac1, regulates the secretory activity of human endometrial stromal cells during decidualization, supporting the concept that this signaling G protein plays a central and conserved role in controlling endometrial secretory function. This study provides unique insights into the molecular mechanisms regulating endometrial secretions that mediate stromal-endothelial and stromal-trophoblast crosstalk critical for placenta development and establishment of pregnancy.
CYK-4 regulates Rac, but not Rho, during cytokinesis

PubMed Central

Zhuravlev, Yelena; Hirsch, Sophia M.; Jordan, Shawn N.; Dumont, Julien; Shirasu-Hiza, Mimi; Canman, Julie C.

2017-01-01

Cytokinesis is driven by constriction of an actomyosin contractile ring that is controlled by Rho-family small GTPases. Rho, activated by the guanine-nucleotide exchange factor ECT-2, is upstream of both myosin-II activation and diaphanous formin-mediated filamentous actin (f-actin) assembly, which drive ring constriction. The role for Rac and its regulators is more controversial, but, based on the finding that Rac inactivation can rescue cytokinesis failure when the GTPase-activating protein (GAP) CYK-4 is disrupted, Rac activity was proposed to be inhibitory to contractile ring constriction and thus specifically inactivated by CYK-4 at the division plane. An alternative model proposes that Rac inactivation generally rescues cytokinesis failure by reducing cortical tension, thus making it easier for the cell to divide when ring constriction is compromised. In this alternative model, CYK-4 was instead proposed to activate Rho by binding ECT-2. Using a combination of time-lapse in vivo single-cell analysis and Caenorhabditis elegans genetics, our evidence does not support this alternative model. First, we found that Rac disruption does not generally rescue cytokinesis failure: inhibition of Rac specifically rescues cytokinesis failure due to disruption of CYK-4 or ECT-2 but does not rescue cytokinesis failure due to disruption of two other contractile ring components, the Rho effectors diaphanous formin and myosin-II. Second, if CYK-4 regulates cytokinesis through Rho rather than Rac, then CYK-4 inhibition should decrease levels of downstream targets of Rho. Inconsistent with this, we found no change in the levels of f-actin or myosin-II at the division plane when CYK-4 GAP activity was reduced, suggesting that CYK-4 is not upstream of ECT-2/Rho activation. Instead, we found that the rescue of cytokinesis in CYK-4 mutants by Rac inactivation was Cdc42 dependent. Together our data suggest that CYK-4 GAP activity opposes Rac (and perhaps Cdc42) during cytokinesis. PMID:28298491
R-ketorolac Targets Cdc42 and Rac1 and Alters Ovarian Cancer Cell Behaviors Critical for Invasion and Metastasis

PubMed Central

Guo, Yuna; Kenney, Shelby Ray; Muller, Carolyn Y.; Adams, Sarah; Rutledge, Teresa; Romero, Elsa; Murray-Krezan, Cristina; Prekeris, Rytis; Sklar, Larry A.; Hudson, Laurie G.; Wandinger-Ness, Angela

2015-01-01

Cdc42 (cell division control protein 42) and Rac1 (Ras-related C3 botulinum toxin substrate 1) are attractive therapeutic targets in ovarian cancer based on established importance in tumor cell migration, adhesion and invasion. Despite a predicted benefit, targeting GTPases has not yet been translated to clinical practice. We previously established that Cdc42 and constitutively active Rac1b are overexpressed in primary ovarian tumor tissues. Through high throughput screening and computational shape homology approaches we identified R-ketorolac as a Cdc42 and Rac1 inhibitor; distinct from the anti-inflammatory, cyclooxygenase inhibitory activity of S-ketorolac. In the present study, we establish R-ketorolac as an allosteric inhibitor of Cdc42 and Rac1. Cell-based assays validate R-ketorolac activity against Cdc42 and Rac1. Studies on immortalized human ovarian adenocarcinoma cells (SKOV3ip), and primary, patient-derived ovarian cancer cells show R-ketorolac is a robust inhibitor of growth factor or serum dependent Cdc42 and Rac1 activation with a potency and cellular efficacy similar to small molecule inhibitors of Cdc42 (CID2950007/ML141) and Rac1 (NSC23766). Furthermore, GTPase inhibition by R-ketorolac reduces downstream p21-activated kinases (PAK1/PAK2) effector activation by >80%. Multiple assays of cell behavior using SKOV3ip and primary patient-derived ovarian cancer cells show that R-ketorolac significantly inhibits cell adhesion, migration and invasion. In sum, we provide evidence for R-ketorolac as direct inhibitor of Cdc42 and Rac1 that is capable of modulating downstream GTPase-dependent, physiological responses, which are critical to tumor metastasis. Our findings demonstrate the selective inhibition of Cdc42 and Rac1 GTPases by an FDA approved drug-racemic ketorolac that can be used in humans. PMID:26206334
R-Ketorolac Targets Cdc42 and Rac1 and Alters Ovarian Cancer Cell Behaviors Critical for Invasion and Metastasis.

PubMed

Guo, Yuna; Kenney, S Ray; Muller, Carolyn Y; Adams, Sarah; Rutledge, Teresa; Romero, Elsa; Murray-Krezan, Cristina; Prekeris, Rytis; Sklar, Larry A; Hudson, Laurie G; Wandinger-Ness, Angela

2015-10-01

Cdc42 (cell division control protein 42) and Rac1 (Ras-related C3 botulinum toxin substrate 1) are attractive therapeutic targets in ovarian cancer based on established importance in tumor cell migration, adhesion, and invasion. Despite a predicted benefit, targeting GTPases has not yet been translated to clinical practice. We previously established that Cdc42 and constitutively active Rac1b are overexpressed in primary ovarian tumor tissues. Through high-throughput screening and computational shape homology approaches, we identified R-ketorolac as a Cdc42 and Rac1 inhibitor, distinct from the anti-inflammatory, cyclooxygenase inhibitory activity of S-ketorolac. In the present study, we establish R-ketorolac as an allosteric inhibitor of Cdc42 and Rac1. Cell-based assays validate R-ketorolac activity against Cdc42 and Rac1. Studies on immortalized human ovarian adenocarcinoma cells (SKOV3ip) and primary patient-derived ovarian cancer cells show that R-ketorolac is a robust inhibitor of growth factor or serum-dependent Cdc42 and Rac1 activation with a potency and cellular efficacy similar to small-molecule inhibitors of Cdc42 (CID2950007/ML141) and Rac1 (NSC23766). Furthermore, GTPase inhibition by R-ketorolac reduces downstream p21-activated kinases (PAK1/PAK2) effector activation by >80%. Multiple assays of cell behavior using SKOV3ip and primary patient-derived ovarian cancer cells show that R-ketorolac significantly inhibits cell adhesion, migration, and invasion. In summary, we provide evidence for R-ketorolac as a direct inhibitor of Cdc42 and Rac1 that is capable of modulating downstream GTPase-dependent, physiologic responses, which are critical to tumor metastasis. Our findings demonstrate the selective inhibition of Cdc42 and Rac1 GTPases by an FDA-approved drug, racemic ketorolac, that can be used in humans. ©2015 American Association for Cancer Research.
Upper Atmosphere Research Satellite (UARS) trade analysis

NASA Technical Reports Server (NTRS)

Fox, M. M.; Nebb, J.

1983-01-01

The Upper Atmosphere Research Satellite (UARS) which will collect data pertinent to the Earth's upper atmosphere is described. The collected data will be sent to the central data handling facility (CDHF) via the UARS ground system and the data will be processed and distributed to the remote analysis computer systems (RACS). An overview of the UARS ground system is presented. Three configurations were developed for the CDHF-RACS system. The CDHF configurations are discussed. The IBM CDHF configuration, the UNIVAC CDHF configuration and the vax cluster CDHF configuration are presented. The RACS configurations, the IBM RACS configurations, UNIVAC RACS and VAX RACS are detailed. Due to the large on-line data estimate to approximately 100 GB, a mass storage system is considered essential to the UARS CDHF. Mass storage systems were analyzed and the Braegan ATL, the RCA optical disk, the IBM 3850 and the MASSTOR M860 are discussed. It is determined that the type of mass storage system most suitable to UARS is the automated tape/cartridge device. Two devices of this type, the IBM 3850 and the MASSTOR MSS are analyzed and the applicable tape/cartridge device is incorporated into the three CDHF-RACS configurations.
Optimization of WAVE2 complex–induced actin polymerization by membrane-bound IRSp53, PIP3, and Rac

PubMed Central

Suetsugu, Shiro; Kurisu, Shusaku; Oikawa, Tsukasa; Yamazaki, Daisuke; Oda, Atsushi; Takenawa, Tadaomi

2006-01-01

WAVE2 activates the actin-related protein (Arp) 2/3 complex for Rac-induced actin polymerization during lamellipodium formation and exists as a large WAVE2 protein complex with Sra1/PIR121, Nap1, Abi1, and HSPC300. IRSp53 binds to both Rac and Cdc42 and is proposed to link Rac to WAVE2. We found that the knockdown of IRSp53 by RNA interference decreased lamellipodium formation without a decrease in the amount of WAVE2 complex. Localization of WAVE2 at the cell periphery was retained in IRSp53 knockdown cells. Moreover, activated Cdc42 but not Rac weakened the association between WAVE2 and IRSp53. When we measured Arp2/3 activation in vitro, the WAVE2 complex isolated from the membrane fraction of cells was fully active in an IRSp53-dependent manner but WAVE2 isolated from the cytosol was not. Purified WAVE2 and purified WAVE2 complex were activated by IRSp53 in a Rac-dependent manner with PIP3-containing liposomes. Therefore, IRSp53 optimizes the activity of the WAVE2 complex in the presence of activated Rac and PIP3. PMID:16702231
Optimization of WAVE2 complex-induced actin polymerization by membrane-bound IRSp53, PIP(3), and Rac.

PubMed

Suetsugu, Shiro; Kurisu, Shusaku; Oikawa, Tsukasa; Yamazaki, Daisuke; Oda, Atsushi; Takenawa, Tadaomi

2006-05-22

WAVE2 activates the actin-related protein (Arp) 2/3 complex for Rac-induced actin polymerization during lamellipodium formation and exists as a large WAVE2 protein complex with Sra1/PIR121, Nap1, Abi1, and HSPC300. IRSp53 binds to both Rac and Cdc42 and is proposed to link Rac to WAVE2. We found that the knockdown of IRSp53 by RNA interference decreased lamellipodium formation without a decrease in the amount of WAVE2 complex. Localization of WAVE2 at the cell periphery was retained in IRSp53 knockdown cells. Moreover, activated Cdc42 but not Rac weakened the association between WAVE2 and IRSp53. When we measured Arp2/3 activation in vitro, the WAVE2 complex isolated from the membrane fraction of cells was fully active in an IRSp53-dependent manner but WAVE2 isolated from the cytosol was not. Purified WAVE2 and purified WAVE2 complex were activated by IRSp53 in a Rac-dependent manner with PIP(3)-containing liposomes. Therefore, IRSp53 optimizes the activity of the WAVE2 complex in the presence of activated Rac and PIP(3).
Decreased Rac1 Cardiac Expression in Nitrofen-Induced Diaphragmatic Hernia.

PubMed

Nakamura, Hiroki; Zimmer, Julia; Puri, Prem

2018-02-01

The high incidence of cardiac malformations in humans and animal models with congenital diaphragmatic hernia (CDH) is well known. The hypoplasia of left heart is common among fetuses with CDH and has been identified as a poor prognostic factor. However, the precise mechanisms underlying cardiac maldevelopment in CDH are not fully understood. Ras-related C3 botulinum toxin substrate 1 (Rac1) plays a key role in cardiomyocyte polarity and embryonic heart development. Deficiency of Rac1 is reported to impair elongation and cytoskeletal organization of cardiomyocytes, resulting in congenital cardiac defects. We designed this study to test the hypothesis that Rac1 expression is downregulated in the developing hearts of rats with nitrofen-induced CDH. Following ethical approval (REC1103), time-pregnant Sprague Dawley rats received nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D18 and D21 and divided into CDH and control (CTRL) ( n = 6 for each group and time point). Quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and confocal-immunofluorescence microscopy were performed to detect cardiac gene and protein expression of Rac1. qRT-PCR and Western blot analysis revealed that Rac1 expression was significantly decreased in the CDH group compared with controls ( p < 0.05). Confocal-immunofluorescence microscopy revealed that Rac1 cardiac expression was markedly decreased in the CDH group compared with controls. Decreased cardiac Rac1 expression in the nitrofen-induced CDH suggests that Rac1 deficiency during morphogenesis may impair structural cardiac remodeling, resulting in congenital cardiac defects. Georg Thieme Verlag KG Stuttgart · New York.
Rac1 and Cdc42 Differentially Modulate Cigarette Smoke–Induced Airway Cell Migration through p120-Catenin–Dependent and –Independent Pathways

PubMed Central

Zhang, Lili; Gallup, Marianne; Zlock, Lorna; Finkbeiner, Walter E.; McNamara, Nancy A.

2014-01-01

The adherens junction protein p120-catenin (p120ctn) shuttles between E-cadherin–bound and cytoplasmic pools to regulate E-cadherin/catenin complex stability and cell migration, respectively. When released from the adherens junction, p120ctn promotes cell migration through modulation of the Rho GTPases Rac1, Cdc42, and RhoA. Accordingly, the down-regulation and cytoplasmic mislocalization of p120ctn has been reported in all subtypes of lung cancers and is associated with grave prognosis. Previously, we reported that cigarette smoke induced cytoplasmic translocation of p120ctn and cell migration, but the underlying mechanism was unclear. Using primary human bronchial epithelial cells exposed to smoke-concentrated medium (Smk), we observed the translocation of Rac1 and Cdc42, but not RhoA, to the leading edge of polarized and migrating human bronchial epithelial cells. Rac1 and Cdc42 were robustly activated by smoke, whereas RhoA was inhibited. Accordingly, siRNA knockdown of Rac1 or Cdc42 completely abolished Smk-induced cell migration, whereas knockdown of RhoA had no effect. p120ctn/Rac1 double knockdown completely abolished Smk-induced cell migration, whereas p120ctn/Cdc42 double knockdown did not. These data suggested that Rac1 and Cdc42 coactivation was essential to smoke-promoted cell migration in the presence of p120ctn, whereas migration proceeded via Rac1 alone in the absence of p120ctn. Thus, Rac1 may provide an omnipotent therapeutic target in reversing cell migration during the early (intact p120ctn) and late (loss of p120ctn) stages of lung carcinogenesis. PMID:23562274
Blocking hepatic metastases of colon cancer cells using an shRNA against Rac1 delivered by activatable cell-penetrating peptide.

PubMed

Bao, Ying; Guo, Huihui; Lu, Yongliang; Feng, Wenming; Sun, Xinrong; Tang, Chengwu; Wang, Xiang; Shen, Mo

2016-11-22

Hepatic metastasis is one of the critical progressions of colon cancer. Blocking this process is key to prolonging survival time in cancer patients. Studies on activatable cell-penetrating peptides (dtACPPs) have demonstrated their potential as gene carriers. It showed high tumor cell-targeting specificity and transfection efficiency and low cytotoxicity in the in vitro settings of drug delivery. However, using this system to silence target genes to inhibit metastasis in colorectal cancer cells has not been widely reported and requires further investigation. In this study, we observed that expression of Rac1, a key molecule for cytoskeletal reorganization, was higher in hepatic metastatic tumor tissue compared with prime colon cancer tissue and that patients with high Rac1-expressing colon cancer showed shorter survival time. Base on these findings, we created dtACPP-PEG-DGL (dtACPPD)/shRac1 nanoparticles and demonstrated that they downregulated Rac1 expression in colon cancer cells. Moreover, we observed inhibitory effects on migration, invasion and adhesion in HCT116 colorectal cancer cells in vitro, and our results showed that Rac1 regulated colon cancer cell matrix adhesion through the regulation of cytofilament dynamics. Moreover, mechanically, repression of Rac1 inhibiting cells migration and invasion by enhancing cell to cell adhesion and reducing cell to extracellular matrix adhesion. Furthermore, when atCDPPD/shRac1 nanoparticles were administered intravenously to a HCT116 xenograft model, significant tumor metastasis to the liver was inhibited. Our results suggest that atCDPP/shRac1 nanoparticles may enable the blockade of hepatic metastasis in colon cancer.
Effect of dietary zinc and ractopamine hydrochloride on pork chop muscle fiber type distribution, tenderness, and color characteristics.

PubMed

Paulk, C B; Tokach, M D; Nelssen, J L; Burnett, D D; Vaughn, M A; Phelps, K J; Dritz, S S; Derouchey, J M; Goodband, R D; Woodworth, J C; Houser, T A; Haydon, K D; Gonzalez, J M

2014-05-01

A total of 320 finishing pigs (PIC 327 × 1050; initially 98 kg) were used to determine the effects of adding Zn to diets containing ractopamine HCl (RAC) on muscle fiber type distribution, fresh chop color, and cooked meat characteristics. Dietary treatments were fed for approximately 35 d and consisted of a corn-soybean meal-based negative control (CON), a positive control diet with 10 mg/kg of RAC (RAC+), and the RAC+ diet plus 75, 150, or 225 mg/kg added Zn from either ZnO or Availa-Zn. Loins randomly selected from each treatment (n = 20) were evaluated using contrasts: CON vs. RAC+, interaction of Zn level × source, Zn level linear and quadratic polynomials, and Zn source. There were no Zn source effects or Zn source × level interactions throughout the study (P > 0.10). Pigs fed RAC+ had increased (P < 0.02) percentage type IIX and a tendency for increased (P = 0.10) percent type IIB muscle fibers. Increasing added Zn decreased (linear, P = 0.01) percentage type IIA and tended to increase (P = 0.09) IIX muscle fibers. On d 1, 2, 3, 4, and 5 of display, pork chops from pigs fed the RAC+ treatment had greater (P < 0.03) L* values compared to the CON. On d 0 and 3 of display, increasing added Zn tended to decrease (quadratic, P = 0.10) L* values and decreased (quadratic, P < 0.03) L* values on d 1, 2, 4, and 5. Pigs fed RAC+ had decreased (P < 0.05) a* values on d 1 and 4 of display and tended to have decreased (P < 0.10) a* values on d 0 and 2 compared to CON pork chops. Pork chops from the RAC+ treatment had a tendency for increased (P < 0.08) oxymyoglobin percentage compared to CON pork chops on d 1, 2, 4, and 5. On d 0, as dietary Zn increased in RAC+ diets, there was a decrease (linear, P < 0.01) in the formation of pork chop surface oxymyoglobin percentage. Metmyoglobin reducing ability (MRA) of pork chops on d 5 was decreased in the RAC+ group. Chops from pigs fed added Zn had increased (quadratic, P < 0.03) MRA on d 3 and 5 of the display period. There was a trend for increased (linear, P = 0.07) cooking loss with increasing Zn in RAC diets and treatments did not affect tenderness as measured by Warner-Bratzler shear force (P > 0.07). In conclusion, RAC+ diets produced chops that were lighter and less red but maintained a greater percentage of surface oxymyoglobin throughout a 5-d simulated retail display. Ractopamine reduced MRA at the end of the display period, but supplementing Zn to RAC diets restored MRA to near CON treatment levels at the end of the display period.
75 FR 78966 - Del Norte Resource Advisory Committee (RAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-17

... Washington Boulevard, Crescent City, California 95531. FOR FURTHER INFORMATION CONTACT: Adam Dellinger..., the public will present clarification on previously submitted Title II project proposals to the RAC. The RAC will vote on projects to recommend for funding. There will also be a public comment...
75 FR 69037 - Medicaid Program; Recovery Audit Contractors

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-10

... [CMS-6034-P] RIN 0938-AQ19 Medicaid Program; Recovery Audit Contractors AGENCY: Centers for Medicare... Recovery Audit Contractors (Medicaid RACs) and the payment methodology for State payments to Medicaid RACs... RACs coordinate with other contractors and entities auditing Medicaid providers and with State and...
The Drosophila small GTPase Rac2 is required for normal feeding and mating behaviour.

PubMed

Goergen, Philip; Kasagiannis, Anna; Schiöth, Helgi B; Williams, Michael J

2014-03-01

All multicellular organisms require the ability to regulate bodily processes in order to maintain a stable condition, which necessitates fluctuations in internal metabolics, as well as modifications of outward behaviour. Understanding the genetics behind this modulation is important as a general model for the metabolic modification of behaviour. This study demonstrates that the activity of the small GTPase Rac2 is required in Drosophila for the proper regulation of lipid storage and feeding behaviour, as well as aggression and mating behaviours. Rac2 mutant males and females are susceptible to starvation and contain considerably less lipids than controls. Furthermore, Rac2 mutants also have disrupted feeding behaviour, eating fewer but larger meals than controls. Intriguingly, Rac2 mutant males rarely initiate aggressive behaviour and display significantly increased levels of courtship behaviour towards other males and mated females. From these results we conclude that Rac2 has a central role in regulating the Drosophila homeostatic system.
Slit stimulation recruits Dock and Pak to the roundabout receptor and increases Rac activity to regulate axon repulsion at the CNS midline.

PubMed

Fan, Xueping; Labrador, Juan Pablo; Hing, Huey; Bashaw, Greg J

2003-09-25

Drosophila Roundabout (Robo) is the founding member of a conserved family of repulsive axon guidance receptors that respond to secreted Slit proteins. Here we present evidence that the SH3-SH2 adaptor protein Dreadlocks (Dock), the p21-activated serine-threonine kinase (Pak), and the Rac1/Rac2/Mtl small GTPases can function during Robo repulsion. Loss-of-function and genetic interaction experiments suggest that limiting the function of Dock, Pak, or Rac partially disrupts Robo repulsion. In addition, Dock can directly bind to Robo's cytoplasmic domain, and the association of Dock and Robo is enhanced by stimulation with Slit. Furthermore, Slit stimulation can recruit a complex of Dock and Pak to the Robo receptor and trigger an increase in Rac1 activity. These results provide a direct physical link between the Robo receptor and an important cytoskeletal regulatory protein complex and suggest that Rac can function in both attractive and repulsive axon guidance.
Effects of dietary L-carnitine and ractopamine HCl on the metabolic response to handling in finishing pigs.

PubMed

James, B W; Tokach, M D; Goodband, R D; Nelssen, J L; Dritz, S S; Owen, K Q; Woodworth, J C; Sulabo, R C

2013-09-01

Two experiments (384 pigs; C22 × L326; PIC) were conducted to determine the interactive effect of dietary L-carnitine and ractopamine HCl (RAC) on the metabolic response of pigs to handling. Experiments were arranged as split-split plots with handling as the main plot and diets as subplots (4 pens per treatment). Dietary L-carnitine (0 or 50 mg/kg) was fed from 36.0 kg to the end of the experiments (118 kg), and RAC (0 or 20 mg/kg) was fed the last 4 wk of each experiment. At the end of each experiment, 4 pigs per pen were assigned to 1 of 2 handling treatments. Gently handled pigs were moved at a moderate walking pace 3 times through a 50-m course and up and down a 15° loading ramp. Aggressively handled pigs were moved as fast as possible 3 times through the same course, but up and down a 30° ramp, and shocked 3 times with an electrical prod. Blood was collected immediately before and after handling in Exp. 1 and immediately after and 1 h after handling in Exp. 2. Feeding RAC increased (P < 0.01) ADG and G:F, but there was no effect (P > 0.10) of L-carnitine on growth performance. In Exp. 1 and 2, aggressive handling increased (P < 0.01) blood lactate dehydrogenase (LDH), lactate, cortisol, and rectal temperature and decreased blood pH. In Exp. 1, there was a RAC × handling interaction (P < 0.06) for the difference in pre- and posthandling blood pH and rectal temperature. Aggressively handled pigs fed RAC had decreased blood pH and increased rectal temperature compared with gently handled pigs, demonstrating the validity of the handling model. Pigs fed RAC had increased (P < 0.01) LDH compared with pigs not fed RAC. Pigs fed L-carnitine had increased (P < 0.03) lactate compared with pigs not fed L-carnitine. In Exp. 2, pigs fed RAC had lower (P < 0.02) blood pH immediately after handling, but pH returned to control levels by 1 h posthandling. Lactate, LDH, cortisol, and rectal temperature changes from immediately posthandling to 1 h posthandling were not different (P > 0.10) between pigs fed L-carnitine and those fed RAC, indicating that L-carnitine did not decrease recovery time of pigs subjected to aggressive handling. These results suggest that pigs fed 20 mg/kg of RAC are more susceptible to stress when handled aggressively compared with pigs not fed RAC. Dietary L-carnitine fed in combination with RAC did not alleviate the effects of stress. This research emphasizes the importance of using proper animal handling techniques when marketing finishing pigs fed RAC.

Impact of ractopamine hydrochloride on growth, efficiency, and carcass traits of finishing pigs in a three-phase marketing strategy.

PubMed

Gerlemann, G D; Allee, G L; Rincker, P J; Ritter, M J; Boler, D D; Carr, S N

2014-03-01

The objectives were to determine the effects of ractopamine hydrochloride (RAC) in a 3-phase marketing strategy. One thousand seven hundred forty pigs were used in 80 single-sex pens in 2 blocks. Each pen housed approximately 22 pigs. Sixteen percent of the total population of pigs was sold during the first marketing period, 18% was sold during the second marketing period, and the remaining 66% was sold during the third marketing period. Data were analyzed as a randomized complete block design of 2 treatments. Pigs in the second marketing group had greater growth performance indicators than pigs in the first marketing group. Over the entire feeding period, pigs fed RAC were 2.73 kg heavier (P < 0.0001), had 0.11 kg/d greater (P < 0.0001) ADG, and had 0.04 greater (P < 0.0001) G:F than pigs not fed RAC. Hot carcass weights were 3.3% greater (P < 0.0001), carcass yields were 0.68 (% units) greater (P < 0.0001), fat depth was 7.2% less (P < 0.0001), loin depth was 5.6% greater (P < 0.0001), and estimated carcass lean was 0.97% units greater (P < 0.0001) in RAC-fed pigs when compared with pigs not fed RAC. By the end of the first marketing period carcasses from pigs fed RAC (89.73 kg) were 2.1% heavier (P = 0.04) and gained 0.19 kg/d more (P = 0.03) carcass weight than carcasses from pigs not fed RAC (87.89 kg). By the end of the second marketing period carcasses from pigs fed RAC (99.00 kg) were 3.1% heavier (P < 0.001) and gained 0.14 kg/d more (P < 0.001) carcass weight than carcasses from pigs not fed RAC (96.02 kg). By the end of the third marketing period carcasses from pigs fed RAC (102.75 kg) were 3.7% heavier (P < 0.0001) and gained 0.10 kg/d more (P < 0.0001) carcass weight than carcasses from pigs not fed RAC (99.06 kg). Although carcass gain per day decreased with extended RAC feeding duration, HCW advantages continued to increase as feeding duration was increased from 7 d to 35 d. Growth benefits were evident during the initial marketing period, but as duration increased differences diminished. Therefore, RAC can provide the expected growth performance benefits when included in the diet for up to 21 d, but HCW advantages continue to increase throughout the entire 35 d feeding period. Even though carcass benefits were not as evident in pigs sold during the first marketing period, advantages (particularly HCW) continued to increase with each marketing period.
Hydrostatic pressure promotes the proliferation and osteogenic/chondrogenic differentiation of mesenchymal stem cells: The roles of RhoA and Rac1.

PubMed

Zhao, Yin-Hua; Lv, Xin; Liu, Yan-Li; Zhao, Ying; Li, Qiang; Chen, Yong-Jin; Zhang, Min

2015-05-01

Our previous studies have shown that hydrostatic pressure can serve as an active regulator for bone marrow mesenchymal stem cells (BMSCs). The current work further investigates the roles of cytoskeletal regulatory proteins Ras homolog gene family member A (RhoA) and Ras-related C3 botulinum toxin substrate 1 (Rac1) in hydrostatic pressure-related effects on BMSCs. Flow cytometry assays showed that the hydrostatic pressure promoted cell cycle initiation in a RhoA- and Rac1-dependent manner. Furthermore, fluorescence assays confirmed that RhoA played a positive and Rac1 displayed a negative role in the hydrostatic pressure-induced F-actin stress fiber assembly. Western blots suggested that RhoA and Rac1 play central roles in the pressure-inhibited ERK phosphorylation, and Rac1 but not RhoA was involved in the pressure-promoted JNK phosphorylation. Finally, real-time polymerase chain reaction (PCR) experiments showed that pressure promoted the expression of osteogenic marker genes in BMSCs at an early stage of osteogenic differentiation through the up-regulation of RhoA activity. Additionally, the PCR results showed that pressure enhanced the expression of chondrogenic marker genes in BMSCs during chondrogenic differentiation via the up-regulation of Rac1 activity. Collectively, our results suggested that RhoA and Rac1 are critical to the pressure-induced proliferation and differentiation, the stress fiber assembly, and MAPK activation in BMSCs. Copyright © 2015. Published by Elsevier B.V.
Evaluating the Dimensionality of Self-Determination Theory's Relative Autonomy Continuum.

PubMed

Sheldon, Kennon M; Osin, Evgeny N; Gordeeva, Tamara O; Suchkov, Dmitry D; Sychev, Oleg A

2017-09-01

We conducted a theoretical and psychometric evaluation of self-determination theory's "relative autonomy continuum" (RAC), an important aspect of the theory whose validity has recently been questioned. We first derived a Comprehensive Relative Autonomy Index (C-RAI) containing six subscales and 24 items, by conducting a paired paraphrase content analysis of existing RAI measures. We administered the C-RAI to multiple U.S. and Russian samples, assessing motivation to attend class, study a major, and take responsibility. Item-level and scale-level multidimensional scaling analyses, confirmatory factor analyses, and simplex/circumplex modeling analyses reaffirmed the validity of the RAC, across multiple samples, stems, and studies. Validation analyses predicting subjective well-being and trait autonomy from the six separate subscales, in combination with various higher order composites (weighted and unweighted), showed that an aggregate unweighted RAI score provides the most unbiased and efficient indicator of the overall quality of motivation within the behavioral domain being assessed.
[Health evaluation of trichloroethylene in indoor air : communication from the German ad-hoc working group on indoor guidelines of the Indoor Air Hygiene Committee and of the states' supreme health authorities].

PubMed

2015-07-01

In the European Hazardous Substances Regulation No 1272/2008 trichloroethylene has been classified as a probable human carcinogen and a suspected mutagen. According to several Committees (German Committee on Hazardous Substances, European Scientific Committee on Occupational Exposure Limits, European Chemicals Agency´s Committee for Risk Assessment (ECHA-RAC)) concentrations of trichloroethylene cytotoxic to renal tubuli may increase the risk to develop renal cancer. At non-cytotoxic concentrations of trichloroethylene a much lower cancer risk may be assumed. Therefore, evaluating the cancer risk to the public following inhalation of trichloroethylene ECHA-RAC has assumed a sublinear exposure-response relationship for carcinogenicity of trichloroethylene. Specifically, ECHA-RAC assessed a cancer risk of 6.4 × 10(- 5) (mg/m(3))(- 1) following life time exposure to trichloroethylene below a NOAEC for renal cytotoxicity of 6 mg trichloroethylene/m(3). Further evaluation yields a life-time risk of 10(- 6) corresponding to 0.02 mg trichloroethylene/m(3). This concentration is well above the reference (e.g. background) concentration of trichloroethylene in indoor air. Consequently the Ad-hoc Working Group on Indoor Guidelines recommends 0.02 mg trichloroethylene/m(3) as a risk-related guideline for indoor air. Measures to reduce exposure are considered inappropriate at concentrations below this guideline.
76 FR 44602 - State of Arizona Resource Advisory Council Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-26

... Mineral Withdrawal Draft Environmental Impact Statement; presentation and RAC recommendations on the Red Rock Pass Program; RAC questions on District Managers' Reports; reports by the RAC working groups; and... Forest Service recreation fee proposals in Arizona. The RRAC will review the Forest Service's Red Rock...
76 FR 17106 - Secure Rural Schools Resource Advisory Committee (RAC) Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-28

... DEPARTMENT OF AGRICULTURE Forest Service Secure Rural Schools Resource Advisory Committee (RAC... meeting to be held authorized under the Secure Rural Schools Act and Community Self-Determination Act... federally designated Secure Rural Schools Resource Advisory Committee (RAC). The public is invited to attend...
Comparative evaluation of three proliferation markers, Ki-67, TOP2A, and RacGAP1, in bronchopulmonary neuroendocrine neoplasms: Issues and prospects.

PubMed

Neubauer, Elisa; Wirtz, Ralph M; Kaemmerer, Daniel; Athelogou, Maria; Schmidt, Lydia; Sänger, Jörg; Lupp, Amelie

2016-07-05

The classification of bronchopulmonary neuroendocrine neoplasms (BP-NEN) into four tumor entities (typical carcinoids (TC), atypical carcinoids (AC), small cell lung cancers (SCLC), large cell neuroendocrine lung carcinomas (LCNEC)) is difficult to perform accurately, but important for prognostic statements and therapeutic management decisions. In this regard, we compared the expression of three proliferation markers, Ki-67, Topoisomerase II alpha (TOP2A), and RacGAP1, in a series of tumor samples from 104 BP-NEN patients (24 TC, 21 AC, 52 SCLC, 7 LCNEC) using different evaluation methods (immunohistochemistry (IHC): Average evaluation, Hotspot evaluation, digital image analysis; RT-qPCR).The results indicated that all three markers had increased protein and mRNA expression with poorer differentiation and correlated well with each other, as well as with grading, staging, and poor survival. Compared with Ki-67 and TOP2A, RacGAP1 allowed for a clearer prognostic statement. The cut-off limits obtained for Ki-67-Average (IHC) were TC-AC 1.5, AC-SCLC 19, and AC-LCNEC 23.5. The Hotspot evaluation generated equal to higher, the digital image analysis generally lower between-entity cut-off limits.All three markers enabled a clear-cut differentiation between the BP-NEN entities, and all methods evaluated were suitable for marker assessment. However, to define optimal cut-off limits, the Ki-67 evaluation methods should be standardized. RacGAP1 appeared to be a new marker with great potential.
Effect of Rho family GTP-binding proteins on Amoeba proteus.

PubMed

Kłopocka, W; Redowicz, M J

2003-03-01

While there is a number of studies on the effects of Rho GTPases on the actin-based cytoskeleton in higher eukaryotes, studies in protozoans are rather limited. The problem seems to be intriguing since the structure of protozoan cytoskeletons is distinct from most vertebrate cells. By blocking endogenous Rho family proteins of highly motile Amoeba proteus with C3 transferase and antibodies against human RhoA and Rac1, we tried to assess the in vivo role of these proteins in amoebae. In migrating amoebae, both proteins are concentrated in the cortical layer and seem to colocalize with filamentous actin. Endogenous Rac1, but not RhoA, is accumulated in the perinuclear cytoskeleton. Blocking Rac- or Rho-like proteins caused distinct and irreversible changes in the locomotive shape of the examined amoebae and significant inhibition of their migration. Amoebae microinjected with anti-Rac1 antibodies were contracted, shortened, and developed only few wide pseudopodia. More pronounced changes were observed in cells treated with anti-RhoA antibodies. They exhibited an atypical locomotion not leading to their effective displacement. After treatment with 50 microg of C3 transferase per ml, cells rapidly contracted and almost completely rounded up, became refractile with the granules beaten into a dense mass, detached from the surface and died. Ten times lower concentration of the enzyme caused similar changes as the inhibition of endogenous RhoA-like protein. These results indicate that Rho family-based regulation plays a key role in amoebic migration.
75 FR 52551 - Notice of Utah's Resource Advisory Council (RAC) Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-26

... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLUT91000-L10400000-PH0000-24-1A] Notice of Utah's Resource Advisory Council (RAC) Meeting AGENCY: Bureau of Land Management, Interior. ACTION.... Department of the Interior, Bureau of Land Management's (BLM) Utah Resource Advisory Council (RAC) will meet...
75 FR 6060 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-05

... Meeting, Southwest Colorado Resource Advisory Council Meeting AGENCY: Bureau of Land Management. ACTION... Land Management (BLM) Southwest Colorado Resource Advisory Council (RAC) will meet in March 2010. DATES: A Southwest Colorado RAC meeting will be held March 5, 2010. ADDRESSES: The Southwest Colorado RAC...
Coactosin accelerates cell dynamism by promoting actin polymerization.

PubMed

Hou, Xubin; Katahira, Tatsuya; Ohashi, Kazumasa; Mizuno, Kensaku; Sugiyama, Sayaka; Nakamura, Harukazu

2013-07-01

During development, cells dynamically move or extend their processes, which are achieved by actin dynamics. In the present study, we paid attention to Coactosin, an actin binding protein, and studied its role in actin dynamics. Coactosin was associated with actin and Capping protein in neural crest cells and N1E-115 neuroblastoma cells. Accumulation of Coactosin to cellular processes and its association with actin filaments prompted us to reveal the effect of Coactosin on cell migration. Coactosin overexpression induced cellular processes in cultured neural crest cells. In contrast, knock-down of Coactosin resulted in disruption of actin polymerization and of neural crest cell migration. Importantly, Coactosin was recruited to lamellipodia and filopodia in response to Rac signaling, and mutated Coactosin that cannot bind to F-actin did not react to Rac signaling, nor support neural crest cell migration. It was also shown that deprivation of Rac signaling from neural crest cells by dominant negative Rac1 (DN-Rac1) interfered with neural crest cell migration, and that co-transfection of DN-Rac1 and Coactosin restored neural crest cell migration. From these results we have concluded that Coactosin functions downstream of Rac signaling and that it is involved in neurite extension and neural crest cell migration by actively participating in actin polymerization. Copyright © 2013 Elsevier Inc. All rights reserved.
Distinctive and selective route of PI3K/PKCα-PKCδ/RhoA-Rac1 signaling in osteoclastic cell migration.

PubMed

Kim, Jin-Man; Kim, Mi Yeong; Lee, Kyunghee; Jeong, Daewon

2016-12-05

Cell migration during specialized stages of osteoclast precursors, mononuclear preosteoclasts, and multinucleated mature osteoclasts remain uncertain. M-CSF- and osteopontin-induced osteoclastic cell migration was inhibited by function-blocking monoclonal antibodies specific to the integrin αv and β3 subunits, suggesting that integrin αvβ3 mediates migratory signaling induced by M-CSF and osteopontin. M-CSF and osteopontin stimulation was shown to regulate two branched signaling processes, PI3K/PKCα/RhoA axis and PI3K/PKCδ/Rac1 axis. Interestingly, inactivation of RhoA or Rac1 blocked preosteoclast and mature osteoclast migration but not osteoclast precursor migration in a transwell-based cell migration assay. Moreover, the inhibitory effect on preosteoclast and mature osteoclast migration induced by Rac1 inactivation was more effective than that by RhoA inactivation. Collectively, our findings suggest that osteoclast precursor migration depends on PI3K/PKCα-PKCδ signaling mediated via integrin αvβ3 bypassing RhoA and Rac1, whereas preosteoclast and mature osteoclast migration relies on PI3K/PKCα-PKCδ/RhoA-Rac1 axis signaling mediated via integrin αvβ3 with increased dependency on PKCδ/Rac1 signaling route as differentiation progresses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Rac-mediated Stimulation of Phospholipase Cγ2 Amplifies B Cell Receptor-induced Calcium Signaling*♦

PubMed Central

Walliser, Claudia; Tron, Kyrylo; Clauss, Karen; Gutman, Orit; Kobitski, Andrei Yu.; Retlich, Michael; Schade, Anja; Röcker, Carlheinz; Henis, Yoav I.; Nienhaus, G. Ulrich; Gierschik, Peter

2015-01-01

The Rho GTPase Rac is crucially involved in controlling multiple B cell functions, including those regulated by the B cell receptor (BCR) through increased cytosolic Ca2+. The underlying molecular mechanisms and their relevance to the functions of intact B cells have thus far remained unknown. We have previously shown that the activity of phospholipase Cγ2 (PLCγ2), a key constituent of the BCR signalosome, is stimulated by activated Rac through direct protein-protein interaction. Here, we use a Rac-resistant mutant of PLCγ2 to functionally reconstitute cultured PLCγ2-deficient DT40 B cells and to examine the effects of the Rac-PLCγ2 interaction on BCR-mediated changes of intracellular Ca2+ and regulation of Ca2+-regulated and nuclear-factor-of-activated-T-cell-regulated gene transcription at the level of single, intact B cells. The results show that the functional Rac-PLCγ2 interaction causes marked increases in the following: (i) sensitivity of B cells to BCR ligation; (ii) BCR-mediated Ca2+ release from intracellular stores; (iii) Ca2+ entry from the extracellular compartment; and (iv) nuclear translocation of the Ca2+-regulated nuclear factor of activated T cells. Hence, Rac-mediated stimulation of PLCγ2 activity serves to amplify B cell receptor-induced Ca2+ signaling. PMID:25903139
Adenylyl cyclase localization to the uropod of aggregating Dictyostelium cells requires RacC

PubMed Central

Wang, C.; Jung, D.; Cao, Z.; Chung, C. Y.

2015-01-01

The localization of adenylyl cyclase A (ACA) to uropod of cells is required for the stream formation during Dictyostelium development. RacC is a Dictyostelium orthologue of Cdc42. We identified a streaming defect of racC− cells as they are clearly less polarized and form smaller and fragmented streams. ACA-YFP is mainly associated with intracellular vesicular structures, but not with the plasma membrane in racC− cells. racC− cells have a slightly higher number of vesicles than Ax3 cells, suggesting that the defect of ACA trafficking is not simply due to the lack of vesicle formation. While the ACA-YFP vesicles traveled with an average velocity of 9.1 µm/min in Ax3 cells, a slow and diffusional movement without direction with an average velocity of 4 µm/min was maintained in racC− cells. Images acquired by using total internal reflection fluorescence (TIRF) microscopy and fluorescence recovery after photobleaching (FRAP) analysis revealed that a significantly decreased number of ACA-YFP vesicles appeared near the cell membrane, indicating a defect in ACA-YFP vesicle trafficking. These results suggest an important role of RacC in the rapid and directional movements of ACA vesicles on microtubules to the plasma membrane, especially to the back of polarized cell. PMID:26315268
Intracellular mature IL-37 suppresses tumor metastasis via inhibiting Rac1 activation.

PubMed

Li, Y; Zhao, M; Guo, C; Chu, H; Li, W; Chen, X; Wang, X; Li, Y; Jia, Y; Koussatidjoa, S; Zhu, F; Wang, J; Wang, X; Wang, Q; Zhao, W; Shi, Y; Chen, W; Zhang, L

2018-02-22

IL-37, a newly found anti-inflammatory cytokine of the IL-1 family, has both extracellular and intracellular functions. Accumulating evidences indicate that it is also involved in tumor progression. However, the mechanism and its intracellular target are unclear. In this study, clinical data from 84 patients showed that loss or reduced expression of IL-37 in lung adenocarcinoma tissues was significantly associated with tumor metastasis. We further provided evidence that IL-37 inhibited effectively tumor metastasis in vitro and in vivo. Moreover, we uncovered a novel mechanism by which IL-37 suppressed tumor cell migration via its intracellular mature form (amino acids 46-218). Intracellular mature form of IL-37, but not its extracellular form, markedly inhibited migration of multiple kinds of tumor cells through inhibiting Rac1 activation. Mechanistically, intracellular mature IL-37 directly bound to the CAAX motif in the C-terminal hypervariable region of Rac1, and then inhibited Rac1 membrane translocation and subsequent downstream signaling. Our research identifies intracellular mature IL-37 as a novel endogenous inhibitor of Rac1. Given the crucial roles of Rac1 in tumor angiogenesis and metastasis, intracellular mature IL-37 might serve as a potential strategy for the control of Rac1 activity and tumor progression.
RCP-driven α5β1 recycling suppresses Rac and promotes RhoA activity via the RacGAP1-IQGAP1 complex.

PubMed

Jacquemet, Guillaume; Green, David M; Bridgewater, Rebecca E; von Kriegsheim, Alexander; Humphries, Martin J; Norman, Jim C; Caswell, Patrick T

2013-09-16

Inhibition of αvβ3 or expression of mutant p53 promotes invasion into fibronectin (FN)-containing extracellular matrix (ECM) by enhancing Rab-coupling protein (RCP)-dependent recycling of α5β1 integrin. RCP and α5β1 cooperatively recruit receptor tyrosine kinases, including EGFR1, to regulate their trafficking and downstream signaling via protein kinase B (PKB)/Akt, which, in turn, promotes invasive migration. In this paper, we identify a novel PKB/Akt substrate, RacGAP1, which is phosphorylated as a consequence of RCP-dependent α5β1 trafficking. Phosphorylation of RacGAP1 promotes its recruitment to IQGAP1 at the tips of invasive pseudopods, and RacGAP1 then locally suppresses the activity of the cytoskeletal regulator Rac and promotes the activity of RhoA in this subcellular region. This Rac to RhoA switch promotes the extension of pseudopodial processes and invasive migration into FN-containing matrices, in a RhoA-dependent manner. Thus, the localized endocytic trafficking of α5β1 within the tips of invasive pseudopods elicits signals that promote the reorganization of the actin cytoskeleton, protrusion, and invasion into FN-rich ECM.
RCP-driven α5β1 recycling suppresses Rac and promotes RhoA activity via the RacGAP1–IQGAP1 complex

PubMed Central

Jacquemet, Guillaume; Green, David M.; Bridgewater, Rebecca E.; von Kriegsheim, Alexander; Humphries, Martin J.; Norman, Jim C.

2013-01-01

Inhibition of αvβ3 or expression of mutant p53 promotes invasion into fibronectin (FN)-containing extracellular matrix (ECM) by enhancing Rab-coupling protein (RCP)–dependent recycling of α5β1 integrin. RCP and α5β1 cooperatively recruit receptor tyrosine kinases, including EGFR1, to regulate their trafficking and downstream signaling via protein kinase B (PKB)/Akt, which, in turn, promotes invasive migration. In this paper, we identify a novel PKB/Akt substrate, RacGAP1, which is phosphorylated as a consequence of RCP-dependent α5β1 trafficking. Phosphorylation of RacGAP1 promotes its recruitment to IQGAP1 at the tips of invasive pseudopods, and RacGAP1 then locally suppresses the activity of the cytoskeletal regulator Rac and promotes the activity of RhoA in this subcellular region. This Rac to RhoA switch promotes the extension of pseudopodial processes and invasive migration into FN-containing matrices, in a RhoA-dependent manner. Thus, the localized endocytic trafficking of α5β1 within the tips of invasive pseudopods elicits signals that promote the reorganization of the actin cytoskeleton, protrusion, and invasion into FN-rich ECM. PMID:24019536
How do community-dwelling LGBT people perceive sexuality in residential aged care? A systematic literature review.

PubMed

Mahieu, Lieslot; Cavolo, Alice; Gastmans, Chris

2018-01-22

To investigate what empirical studies report on the perceptions of community-dwelling LGBT adults regarding sexuality and sexual expression in residential aged care (RAC), and how their sexuality should be addressed in RAC. Relevant papers were identified through electronic searches in databases; and by reference tracking and citation tracking. Data were extracted using a standardized data extraction form and were compared, related, and synthesized using thematic analyses. We evaluated the methodological quality of the studies. Eighteen articles were identified. Three major topics emerged regarding sexuality in RAC: (1) factors affecting LGBT people's perceptions, subdivided into (a) discrimination, (b) loss of sexual identity, (c) failure to acknowledge the same-sex partner, and (d) lack of privacy; (2) LGBT-specific RAC facilities; and (3) characteristics of LGBT friendly RAC facilities and caregivers. LGBT people have clear perceptions about how sexuality and sexual expression is or should be managed in RAC. Despite the general increase in acceptance of sexual minorities, many community-dwelling LGBT people believe older LGBT residents are discriminated against because of their sexual orientation or gender identity. Taking into account these opinions is crucial for increasing accessibility of RAC to LGBT people and to ensure the quality of the provided care.
Different roles of the small GTPases Rac1, Cdc42, and RhoG in CALEB/NGC-induced dendritic tree complexity.

PubMed

Schulz, Jana; Franke, Kristin; Frick, Manfred; Schumacher, Stefan

2016-10-01

Rho GTPases play prominent roles in the regulation of cytoskeletal reorganization. Many aspects have been elaborated concerning the individual functions of Rho GTPases in distinct signaling pathways leading to cytoskeletal rearrangements. However, major questions have yet to be answered regarding the integration and the signaling hierarchy of different Rho GTPases in regulating the cytoskeleton in fundamental physiological events like neuronal process differentiation. Here, we investigate the roles of the small GTPases Rac1, Cdc42, and RhoG in defining dendritic tree complexity stimulated by the transmembrane epidermal growth factor family member CALEB/NGC. Combining gain-of-function and loss-of-function analysis in primary hippocampal neurons, we find that Rac1 is essential for CALEB/NGC-mediated dendritic branching. Cdc42 reduces the complexity of dendritic trees. Interestingly, we identify the palmitoylated isoform of Cdc42 to adversely affect dendritic outgrowth and dendritic branching, whereas the prenylated Cdc42 isoform does not. In contrast to Rac1, CALEB/NGC and Cdc42 are not directly interconnected in regulating dendritic tree complexity. Unlike Rac1, the Rac1-related GTPase RhoG reduces the complexity of dendritic trees by acting upstream of CALEB/NGC. Mechanistically, CALEB/NGC activates Rac1, and RhoG reduces the amount of CALEB/NGC that is located at the right site for Rac1 activation at the cell membrane. Thus, Rac1, Cdc42, and RhoG perform very specific and non-redundant functions at different levels of hierarchy in regulating dendritic tree complexity induced by CALEB/NGC. Rho GTPases play a prominent role in dendritic branching. CALEB/NGC is a transmembrane member of the epidermal growth factor (EGF) family that mediates dendritic branching, dependent on Rac1. CALEB/NGC stimulates Rac1 activity. RhoG inhibits CALEB/NGC-mediated dendritic branching by decreasing the amount of CALEB/NGC at the plasma membrane. Palmitoylated, but not prenylated form of the GTPase Cdc42 decreases dendritic branching. CALEB/NGC and Cdc42 are not directly interconnected in regulating dendritic branching. Thus, CALEB/NGC organizes a Rho GTPase signaling module at the plasma membrane for shaping dendritic trees. © 2016 International Society for Neurochemistry.
Membrane targeting of WAVE2 is not sufficient for WAVE2-dependent actin polymerization: a role for IRSp53 in mediating the interaction between Rac and WAVE2.

PubMed

Abou-Kheir, Wassim; Isaac, Beth; Yamaguchi, Hideki; Cox, Dianne

2008-02-01

Wiskott-Aldrich syndrome protein (WASP)-family verprolin homologous (WAVE) proteins play a major role in Rac-induced actin dynamics, but Rac does not bind directly to WAVE proteins. It has been proposed that either the insulin receptor substrate protein 53 (IRSp53) or a complex of proteins containing Abelson interactor protein 1 (Abi1) mediates the interaction of WAVE2 and Rac. Depletion of endogenous IRSp53 by RNA-mediated interference (RNAi) in a RAW/LR5 macrophage cell line resulted in a significant reduction of Rac1Q61L-induced surface ruffles and colony-stimulating factor 1 (CSF-1)-induced actin polymerization, protrusion and cell migration. However, IRSp53 was not essential for Fcgamma-R-mediated phagocytosis, formation of podosomes or for formation of Cdc42V12-induced filopodia. IRSp53 was found to be present in an immunoprecipitable complex with WAVE2 and Abi1 in a Rac1-activation-dependent manner in RAW/LR5 cells in vivo. Importantly, reduction of endogenous IRSp53 or expression of IRSp53 lacking the WAVE2-binding site (IRSp53DeltaSH3) resulted in a significant reduction in the association of Rac1 with WAVE2 and Abi1, indicating that the association of Rac1 with WAVE2 and Abi1 is IRSp53 dependent. While it has been proposed that WAVE2 activity is regulated by membrane recruitment, membrane targeting of WAVE2 in RAW/LR5 and Cos-7 cells did not induce actin polymerization or protrusion, suggesting that membrane recruitment was insufficient for regulation of WAVE2. Combined, these data suggest that IRSp53 links Rac1 to WAVE2 in vivo and its function is crucial for production of CSF-1-induced F-actin-rich protrusions and cell migration in macrophages. This study indicates that Rac1, along with IRSp53 and Abi1, is involved in a more complex and tight regulation of WAVE2 than one operating solely through membrane localization.

Membrane targeting of WAVE2 is not sufficient for WAVE2 dependent actin polymerization: a role for IRSp53 in mediating the interaction between Rac and WAVE2*

PubMed Central

Abou-Kheir, Wassim; Isaac, Beth; Yamaguchi, Hideki; Cox, Dianne

2009-01-01

Summary Wiskott-Aldrich syndrome protein (WASP)-family verprolin homologous (WAVE) proteins play a major role in Rac-induced actin dynamics, but Rac does not bind directly to WAVE proteins. It has been proposed that either the insulin receptor substrate protein 53 (IRSp53) or a complex of proteins containing Abelson interactor protein 1 (Abi1) mediate the interaction of WAVE2 and Rac. Depletion of endogenous IRSp53 by RNA-mediated interference (RNAi) in a RAW/LR5 macrophage cell line resulted in a significant reduction of Rac1Q61L-induced surface ruffles and colony stimulating factor-1 (CSF-1)-induced actin polymerization, protrusion, and cell migration. However, IRSp53 was not essential for Fcγ-R-mediated phagocytosis, formation of podosomes or for Cdc42V12-induced filopodia. IRSp53 was found to be present in an immunoprecipitatable complex with WAVE2 and Abi1 in a Rac1 activation-dependent manner in RAW/LR5 cells in vivo. Importantly, reduction of endogenous IRSp53 or expression of IRSp53 lacking the WAVE2 binding site (IRSp53ΔSH3) resulted in a significant reduction in the association of Rac1 with WAVE2 and Abi1, indicating that the association of Rac1 with WAVE2 and Abi1 is IRSp53 dependent. While it has been proposed that WAVE2 activity is regulated by membrane recruitment, membrane targeting of WAVE2 in RAW/LR5 and Cos-7 cells did not induce actin polymerization or protrusion suggesting thatt membrane recruitment was insufficient for WAVE2 regulation. Altogether, these data suggest that IRSp53 links Rac1 to WAVE2 in vivo and its function is crucial for CSF-1-induced F-actin rich protrusions and cell migration in macrophages. This study indicates that Rac1, along with IRSp53 and Abi1, is involved in a more complex and tight regulation of WAVE2 than solely through membrane localization. PMID:18198193
Mib1 contributes to persistent directional cell migration by regulating the Ctnnd1-Rac1 pathway.

PubMed

Mizoguchi, Takamasa; Ikeda, Shoko; Watanabe, Saori; Sugawara, Michiko; Itoh, Motoyuki

2017-10-31

Persistent directional cell migration is involved in animal development and diseases. The small GTPase Rac1 is involved in F-actin and focal adhesion dynamics. Local Rac1 activity is required for persistent directional migration, whereas global, hyperactivated Rac1 enhances random cell migration. Therefore, precise control of Rac1 activity is important for proper directional cell migration. However, the molecular mechanism underlying the regulation of Rac1 activity in persistent directional cell migration is not fully understood. Here, we show that the ubiquitin ligase mind bomb 1 (Mib1) is involved in persistent directional cell migration. We found that knockdown of MIB1 led to an increase in random cell migration in HeLa cells in a wound-closure assay. Furthermore, we explored novel Mib1 substrates for cell migration and found that Mib1 ubiquitinates Ctnnd1. Mib1-mediated ubiquitination of Ctnnd1 K547 attenuated Rac1 activation in cultured cells. In addition, we found that posterior lateral line primordium cells in the zebrafish mib1 ta52b mutant showed increased random migration and loss of directional F-actin-based protrusion formation. Knockdown of Ctnnd1 partially rescued posterior lateral line primordium cell migration defects in the mib1 ta52b mutant. Taken together, our data suggest that Mib1 plays an important role in cell migration and that persistent directional cell migration is regulated, at least in part, by the Mib1-Ctnnd1-Rac1 pathway. Published under the PNAS license.
The Guanine Nucleotide Exchange Factor Tiam1 Affects Neuronal Morphology; Opposing Roles for the Small GTPases Rac and Rho

PubMed Central

van Leeuwen, Frank N.; Kain, Hendrie E.T.; van der Kammen, Rob A.; Michiels, Frits; Kranenburg, Onno W.; Collard, John G.

1997-01-01

The invasion-inducing T-lymphoma invasion and metastasis 1 (Tiam1) protein functions as a guanine nucleotide exchange factor (GEF) for the small GTPase Rac1. Differentiation-dependent expression of Tiam1 in the developing brain suggests a role for this GEF and its effector Rac1 in the control of neuronal morphology. Here we show that overexpression of Tiam1 induces cell spreading and affects neurite outgrowth in N1E-115 neuroblastoma cells. These effects are Rac-dependent and strongly promoted by laminin. Overexpression of Tiam1 recruits the α6β1 integrin, a laminin receptor, to specific adhesive contacts at the cell periphery, which are different from focal contacts. Cells overexpressing Tiam1 no longer respond to lysophosphatidic acid– induced neurite retraction and cell rounding, processes mediated by Rho, suggesting that Tiam1-induced activation of Rac antagonizes Rho signaling. This inhibition can be overcome by coexpression of constitutively active RhoA, which may indicate that regulation occurs at the level of Rho or upstream. Conversely, neurite formation induced by Tiam1 or Rac1 is further promoted by inactivating Rho. These results demonstrate that Rac- and Rho-mediated pathways oppose each other during neurite formation and that a balance between these pathways determines neuronal morphology. Furthermore, our data underscore the potential role of Tiam1 as a specific regulator of Rac during neurite formation and illustrate the importance of reciprocal interactions between the cytoskeleton and the extracellular matrix during this process. PMID:9348295
Programmed Application of Transforming Growth Factor β3 and Rac1 Inhibitor NSC23766 Committed Hyaline Cartilage Differentiation of Adipose-Derived Stem Cells for Osteochondral Defect Repair.

PubMed

Zhu, Shouan; Chen, Pengfei; Wu, Yan; Xiong, Si; Sun, Heng; Xia, Qingqing; Shi, Libing; Liu, Huanhuan; Ouyang, Hong Wei

2014-10-01

Hyaline cartilage differentiation is always the challenge with application of stem cells for joint repair. Transforming growth factors (TGFs) and bone morphogenetic proteins can initiate cartilage differentiation but often lead to hypertrophy and calcification, related to abnormal Rac1 activity. In this study, we developed a strategy of programmed application of TGFβ3 and Rac1 inhibitor NSC23766 to commit the hyaline cartilage differentiation of adipose-derived stem cells (ADSCs) for joint cartilage repair. ADSCs were isolated and cultured in a micromass and pellet culture model to evaluate chondrogenic and hypertrophic differentiation. The function of Rac1 was investigated with constitutively active Rac1 mutant and dominant negative Rac1 mutant. The efficacy of ADSCs with programmed application of TGFβ3 and Rac1 inhibitor for cartilage repair was studied in a rat model of osteochondral defects. The results showed that TGFβ3 promoted ADSCs chondro-lineage differentiation and that NSC23766 prevented ADSC-derived chondrocytes from hypertrophy in vitro. The combination of ADSCs, TGFβ3, and NSC23766 promoted quality osteochondral defect repair in rats with much less chondrocytes hypertrophy and significantly higher International Cartilage Repair Society macroscopic and microscopic scores. The findings have illustrated that programmed application of TGFβ3 and Rac1 inhibitor NSC23766 can commit ADSCs to chondro-lineage differentiation and improve the efficacy of ADSCs for cartilage defect repair. These findings suggest a promising stem cell-based strategy for articular cartilage repair. ©AlphaMed Press.
U.S. Naval Forces, Vietnam Monthly Historical Summary for July 1969

DTIC Science & Technology

1969-10-01

accounted for 28 YC, killed and 20 captured. During the last 8 days of Tuly RAC on patrol duties and those in blocking tetions after troop insertions...casialties vere unkiowz. The only other * incident Involving RAC occurred on 27 Tuly when RAC, ebile Sw iting to backload troops, took a *sup= under
RhoB controls endothelial barrier recovery by inhibiting Rac1 trafficking to the cell border

PubMed Central

Marcos-Ramiro, Beatriz; García-Weber, Diego; Barroso, Susana; Feito, Jorge; Ortega, María C.; Cernuda-Morollón, Eva; Reglero-Real, Natalia; Fernández-Martín, Laura; Durán, Maria C.; Alonso, Miguel A.; Correas, Isabel; Cox, Susan; Ridley, Anne J.

2016-01-01

Endothelial barrier dysfunction underlies chronic inflammatory diseases. In searching for new proteins essential to the human endothelial inflammatory response, we have found that the endosomal GTPase RhoB is up-regulated in response to inflammatory cytokines and expressed in the endothelium of some chronically inflamed tissues. We show that although RhoB and the related RhoA and RhoC play additive and redundant roles in various aspects of endothelial barrier function, RhoB specifically inhibits barrier restoration after acute cell contraction by preventing plasma membrane extension. During barrier restoration, RhoB trafficking is induced between vesicles containing RhoB nanoclusters and plasma membrane protrusions. The Rho GTPase Rac1 controls membrane spreading and stabilizes endothelial barriers. We show that RhoB colocalizes with Rac1 in endosomes and inhibits Rac1 activity and trafficking to the cell border during barrier recovery. Inhibition of endosomal trafficking impairs barrier reformation, whereas induction of Rac1 translocation to the plasma membrane accelerates it. Therefore, RhoB-specific regulation of Rac1 trafficking controls endothelial barrier integrity during inflammation. PMID:27138256
Membrane Environment Exerts an Important Influence on Rac-Mediated Activation of Phospholipase Cγ2 ▿ †

PubMed Central

Everett, Katy L.; Buehler, Anja; Bunney, Tom D.; Margineanu, Anca; Baxendale, Rhona W.; Vatter, Petra; Retlich, Michael; Walliser, Claudia; Manning, Hugh B.; Neil, Mark A. A.; Dunsby, Christopher; French, Paul M. W.; Gierschik, Peter; Katan, Matilda

2011-01-01

We performed analyses of the molecular mechanisms involved in the regulation of phospholipase Cγ2 (PLCγ2). We identified several regions in the PLCγ-specific array, γSA, that contribute to autoinhibition in the basal state by occlusion of the catalytic domain. While the activation of PLCγ2 by Rac2 requires stable translocation to the membrane, the removal of the domains required for membrane translocation in the context of an enzyme with impaired autoinhibition generated constitutive, highly active PLC in cells. We further tested the possibility that the interaction of PLCγ2 with its activator protein Rac2 was sufficient for activation through the release of autoinhibition. However, we found that Rac2 binding in the absence of lipid surfaces was not able to activate PLCγ2. Together with other observations, these data suggest that an important consequence of Rac2 binding and translocation to the membrane is that membrane proximity, on its own or together with Rac2, has a role in the release of autoinhibition, resulting in interfacial activation. PMID:21245382
Redox Active Colloids as Discrete Energy Storage Carriers.

PubMed

Montoto, Elena C; Nagarjuna, Gavvalapalli; Hui, Jingshu; Burgess, Mark; Sekerak, Nina M; Hernández-Burgos, Kenneth; Wei, Teng-Sing; Kneer, Marissa; Grolman, Joshua; Cheng, Kevin J; Lewis, Jennifer A; Moore, Jeffrey S; Rodríguez-López, Joaquín

2016-10-12

Versatile and readily available battery materials compatible with a range of electrode configurations and cell designs are desirable for renewable energy storage. Here we report a promising class of materials based on redox active colloids (RACs) that are inherently modular in their design and overcome challenges faced by small-molecule organic materials for battery applications, such as crossover and chemical/morphological stability. RACs are cross-linked polymer spheres, synthesized with uniform diameters between 80 and 800 nm, and exhibit reversible redox activity as single particles, as monolayer films, and in the form of flowable dispersions. Viologen-based RACs display reversible cycling, accessing up to 99% of their capacity and 99 ± 1% Coulombic efficiency over 50 cycles by bulk electrolysis owing to efficient, long-distance intraparticle charge transfer. Ferrocene-based RACs paired with viologen-based RACs cycled efficiently in a nonaqueous redox flow battery employing a simple size-selective separator, thus demonstrating a possible application that benefits from their colloidal dimensions. The unprecedented versatility in RAC synthetic and electrochemical design opens new avenues for energy storage.
Regulation of Neurite Outgrowth in N1E-115 Cells through PDZ-Mediated Recruitment of Diacylglycerol Kinase ζ

PubMed Central

Yakubchyk, Yury; Abramovici, Hanan; Maillet, Jean-Christian; Daher, Elias; Obagi, Christopher; Parks, Robin J.; Topham, Matthew K.; Gee, Stephen H.

2005-01-01

Syntrophins are scaffold proteins that regulate the subcellular localization of diacylglycerol kinase ζ (DGK-ζ), an enzyme that phosphorylates the lipid second-messenger diacylglycerol to yield phosphatidic acid. DGK-ζ and syntrophins are abundantly expressed in neurons of the developing and adult brain, but their function is unclear. Here, we show that they are present in cell bodies, neurites, and growth cones of cultured cortical neurons and differentiated N1E-115 neuroblastoma cells. Overexpression of DGK-ζ in N1E-115 cells induced neurite formation in the presence of serum, which normally prevents neurite outgrowth. This effect was independent of DGK-ζ kinase activity but dependent on a functional C-terminal PDZ-binding motif, which specifically interacts with syntrophin PDZ domains. DGK-ζ mutants with a blocked C terminus acted as dominant-negative inhibitors of outgrowth from serum-deprived N1E-115 cells and cortical neurons. Several lines of evidence suggest DGK-ζ promotes neurite outgrowth through association with the GTPase Rac1. DGK-ζ colocalized with Rac1 in neuronal processes and DGK-ζ-induced outgrowth was inhibited by dominant-negative Rac1. Moreover, DGK-ζ directly interacts with Rac1 through a binding site located within its C1 domains. Together with syntrophin, these proteins form a tertiary complex in N1E-115 cells. A DGK-ζ mutant that mimics phosphorylation of the MARCKS domain was unable to bind an activated Rac1 mutant (Rac1V12) and phorbol myristate acetate-induced protein kinase C activation inhibited the interaction of DGK-ζ with Rac1V12, suggesting protein kinase C-mediated phosphorylation of the MARCKS domain negatively regulates DGK-ζ binding to active Rac1. Collectively, these findings suggest DGK-ζ, syntrophin, and Rac1 form a regulated signaling complex that controls polarized outgrowth in neuronal cells. PMID:16055737
The Small GTPase Rac1 Contributes to Extinction of Aversive Memories of Drug Withdrawal by Facilitating GABAA Receptor Endocytosis in the vmPFC.

PubMed

Wang, Weisheng; Ju, Yun-Yue; Zhou, Qi-Xin; Tang, Jian-Xin; Li, Meng; Zhang, Lei; Kang, Shuo; Chen, Zhong-Guo; Wang, Yu-Jun; Ji, Hui; Ding, Yu-Qiang; Xu, Lin; Liu, Jing-Gen

2017-07-26

Extinction of aversive memories has been a major concern in neuropsychiatric disorders, such as anxiety disorders and drug addiction. However, the mechanisms underlying extinction of aversive memories are not fully understood. Here, we report that extinction of conditioned place aversion (CPA) to naloxone-precipitated opiate withdrawal in male rats activates Rho GTPase Rac1 in the ventromedial prefrontal cortex (vmPFC) in a BDNF-dependent manner, which determines GABA A receptor (GABA A R) endocytosis via triggering synaptic translocation of activity-regulated cytoskeleton-associated protein (Arc) through facilitating actin polymerization. Active Rac1 is essential and sufficient for GABA A R endocytosis and CPA extinction. Knockdown of Rac1 expression within the vmPFC of rats using Rac1-shRNA suppressed GABA A R endocytosis and CPA extinction, whereas expression of a constitutively active form of Rac1 accelerated GABA A R endocytosis and CPA extinction. The crucial role of GABA A R endocytosis in the LTP induction and CPA extinction is evinced by the findings that blockade of GABA A R endocytosis by a dynamin function-blocking peptide (Myr-P4) abolishes LTP induction and CPA extinction. Thus, the present study provides first evidence that Rac1-dependent GABA A R endocytosis plays a crucial role in extinction of aversive memories and reveals the sequence of molecular events that contribute to learning experience modulation of synaptic GABA A R endocytosis. SIGNIFICANCE STATEMENT This study reveals that Rac1-dependent GABA A R endocytosis plays a crucial role in extinction of aversive memories associated with drug withdrawal and identifies Arc as a downstream effector of Rac1 regulations of synaptic plasticity as well as learning and memory, thereby suggesting therapeutic targets to promote extinction of the unwanted memories. Copyright © 2017 the authors 0270-6474/17/377096-15$15.00/0.
Cdc42 and the Guanine Nucleotide Exchange Factors Ect2 and Trio Mediate Fn14-Induced Migration and Invasion of Glioblastoma Cells

PubMed Central

Fortin, Shannon P.; Ennis, Matthew J.; Schumacher, Cassie A.; Zylstra-Diegel, Cassandra R.; Williams, Bart O.; Ross, Julianna T.D.; Winkles, Jeffrey A.; Loftus, Joseph C.; Symons, Marc H.; Tran, Nhan L.

2012-01-01

Malignant glioblastomas are characterized by their ability to infiltrate into normal brain. We previously reported that binding of the multifunctional cytokine TNF-like weak inducer of apoptosis (TWEAK) to its receptor fibroblast growth factor–inducible 14 (Fn14) induces glioblastoma cell invasion via Rac1 activation. Here, we show that Cdc42 plays an essential role in Fn14-mediated activation of Rac1. TWEAK-treated glioma cells display an increased activation of Cdc42, and depletion of Cdc42 using siRNA abolishes TWEAK-induced Rac1 activation and abrogates glioma cell migration and invasion. In contrast, Rac1 depletion does not affect Cdc42 activation by Fn14, showing that Cdc42 mediates TWEAK-stimulated Rac1 activation. Furthermore, we identified two guanine nucleotide exchange factors (GEF), Ect2 and Trio, involved in TWEAK-induced activation of Cdc42 and Rac1, respectively. Depletion of Ect2 abrogates both TWEAK-induced Cdc42 and Rac1 activation, as well as subsequent TWEAK-Fn14–directed glioma cell migration and invasion. In contrast, Trio depletion inhibits TWEAK-induced Rac1 activation but not TWEAK-induced Cdc42 activation. Finally, inappropriate expression of Fn14 or Ect2 in mouse astrocytes in vivo using an RCAS vector system for glial-specific gene transfer in G-tva transgenic mice induces astrocyte migration within the brain, corroborating the in vitro importance of the TWEAK-Fn14 signaling cascade in glioblastoma invasion. Our results suggest that the TWEAK-Fn14 signaling axis stimulates glioma cell migration and invasion through two GEF-GTPase signaling units, Ect2-Cdc42 and Trio-Rac1. Components of the Fn14-Rho GEF-Rho GTPase signaling pathway present innovative drug targets for glioma therapy. PMID:22571869
Provider experiences with RAC appeals point to opportunities for program improvement.

PubMed

Jacobs, Robert; Scott, Bonnie; Flood, Elizabeth; Scott, Ellen

2011-03-01

Review by an administrative law judge (ALJ) constitutes the third level of appeal for healthcare providers seeking to overturn reverse recovery audit contractor (RAC) findings of overpayment of Medicare claims. An analysis of the results of RAC appeals submitted by 30 New York hospitals during the demonstration project has disclosed two deficiencies in the ALJ review process: inconsistent ALJ decision making and a lack of an appropriate feedback mechanism to correct erroneous overpayment determinations. The Centers for Medicare & Medicaid Services should take advantage of feedback from such studies as an impetus to reevaluate and streamline the RAC appeals process.
Rac1 Recruitment to the Archipelago Structure of the Focal Adhesion through the Fluid Membrane as Revealed by Single-Molecule Analysis

PubMed Central

Shibata, Akihiro C E; Chen, Limin H; Nagai, Rie; Ishidate, Fumiyoshi; Chadda, Rahul; Miwa, Yoshihiro; Naruse, Keiji; Shirai, Yuki M; Fujiwara, Takahiro K; Kusumi, Akihiro

2013-01-01

The focal adhesion (FA) is an integrin-based structure built in/on the plasma membrane (PM), linking the extracellular matrix to the actin stress-fibers, working as cell migration scaffolds. Previously, we proposed the archipelago architecture of the FA, in which FA largely consists of fluid membrane, dotted with small islands accumulating FA proteins: membrane molecules enter the inter-island channels in the FA zone rather freely, and the integrins in the FA-protein islands rapidly exchanges with those in the bulk membrane. Here, we examined how Rac1, a small G-protein regulating FA formation, and its activators αPIX and βPIX, are recruited to the FA zones. PIX molecules are recruited from the cytoplasm to the FA zones directly. In contrast, majorities of Rac1 molecules first arrive from the cytoplasm on the general inner PM surface, and then enter the FA zones via lateral diffusion on the PM, which is possible due to rapid Rac1 diffusion even within the FA zones, slowed only by a factor of two to four compared with that outside. The constitutively-active Rac1 mutant exhibited temporary and all-time immobilizations in the FA zone, suggesting that upon PIX-induced Rac1 activation at the FA-protein islands, Rac1 tends to be immobilized at the FA-protein islands. © 2013 Wiley Periodicals, Inc PMID:23341328
The Rac-GAP alpha2-chimaerin regulates hippocampal dendrite and spine morphogenesis.

PubMed

Valdez, Chris M; Murphy, Geoffrey G; Beg, Asim A

2016-09-01

Dendritic spines are fine neuronal processes where spatially restricted input can induce activity-dependent changes in one spine, while leaving neighboring spines unmodified. Morphological spine plasticity is critical for synaptic transmission and is thought to underlie processes like learning and memory. Significantly, defects in dendritic spine stability and morphology are common pathogenic features found in several neurodevelopmental and neuropsychiatric disorders. The remodeling of spines relies on proteins that modulate the underlying cytoskeleton, which is primarily composed of filamentous (F)-actin. The Rho-GTPase Rac1 is a major regulator of F-actin and is essential for the development and plasticity of dendrites and spines. However, the key molecules and mechanisms that regulate Rac1-dependent pathways at spines and synapses are not well understood. We have identified the Rac1-GTPase activating protein, α2-chimaerin, as a critical negative regulator of Rac1 in hippocampal neurons. The loss of α2-chimaerin significantly increases the levels of active Rac1 and induces the formation of aberrant polymorphic dendritic spines. Further, disruption of α2-chimaerin signaling simplifies dendritic arbor complexity and increases the presence of dendritic spines that appear poly-innervated. Our data suggests that α2-chimaerin serves as a "brake" to constrain Rac1-dependent signaling to ensure that the mature morphology of spines is maintained in response to network activity. Copyright © 2016 Elsevier Inc. All rights reserved.
Role of Rac1 in Escherichia coli K1 invasion of human brain microvascular endothelial cells.

PubMed

Rudrabhatla, Rajyalakshmi S; Selvaraj, Suresh K; Prasadarao, Nemani V

2006-02-01

Escherichia coli K1 invasion of human brain microvascular endothelial cells (HBMEC) requires the reorganization of host cytoskeleton at the sites of bacterial entry. Both actin and myosin constitute the cytoskeletal architecture. We have previously shown that myosin light chain (MLC) phosphorylation by MLC kinase is regulated during E. coli invasion by an upstream kinase, p21-activated kinase 1 (PAK1), which is an effector protein of Rac and Cdc42 GTPases, but not of RhoA. Here, we report that the binding of only Rac1 to PAK1 decreases in HBMEC upon infection with E. coli K1, which resulted in increased phosphorylation of MLC. Overexpression of a constitutively active (cAc) form of Rac1 in HBMEC blocked the E. coli invasion significantly, whereas overexpression of a dominant negative form had no effect. Increased PAK1 phosphorylation was observed in HBMEC expressing cAc-Rac1 with a concomitant reduction in the phosphorylation of MLC. Immunocytochemistry studies demonstrated that the inhibition of E. coli invasion into cAc-Rac1/HBMEC is due to lack of phospho-MLC recruitment to the sites of E. coli entry. Taken together the data suggest that E. coli modulates the binding of Rac1, but not Cdc42, to PAK1 during the invasion of HBMEC.
Rac1 modulates the formation of primordial follicles by facilitating STAT3-directed Jagged1, GDF9 and BMP15 transcription in mice

PubMed Central

Zhao, Lihua; Du, Xinhua; Huang, Kun; Zhang, Tuo; Teng, Zhen; Niu, Wanbao; Wang, Chao; Xia, Guoliang

2016-01-01

The size of the primordial follicle pool determines the reproductive potential of mammalian females, and establishment of the pool is highly dependent on specific genes expression. However, the molecular mechanisms by which the essential genes are regulated coordinately to ensure primordial follicle assembly remain a mystery. Here, we show that the small GTPase Rac1 plays an indispensable role in controlling the formation of primordial follicles in mouse ovary. Employing fetal mouse ovary organ culture system, we demonstrate that disruption of Rac1 retarded the breakdown of germline cell cysts while Rac1 overexpression accelerated the formation of primordial follicles. In addition, in vivo inhibitor injection resulted in the formation of multi-oocyte follicles. Subsequent investigation showed that Rac1 induced nuclear import of STAT3 by physical binding. In turn, nuclear STAT3 directly activated the transcription of essential oocyte-specific genes, including Jagged1, GDF9, BMP15 and Nobox. Further, GDF9 and BMP15 regulated the translation of Notch2 via mTORC1 activation in pregranulosa cells. Overexression or addition of Jagged1, GDF9 and BMP15 not only reversed the effect of Rac1 disruption, but also accelerated primordial follicle formation via Notch2 signaling activation. Collectively, these results indicate that Rac1 plays important roles as a key regulator in follicular assembly. PMID:27050391
Implementation Of Palladized Iron-Impregnated Reactive Activated Carbon (RAC) System For PCBs Cleanup: Effects Of PCB Loading, Reaction pH, And Co-Existing NOM And Ionic Species

EPA Science Inventory

For the treatment of chlorinated organic compounds in the environment, such as polychlorinated biphenyls (PCBs), we have developed reactive activated carbon (RAC) impregnated with Fe/Pd bimetallic nanoparticles. The RAC system can couple adsorption of PCBs to activated carbon wi...
Active Tailoring of Lift Distribution to Enhance Cruise Performance

NASA Technical Reports Server (NTRS)

Flamm, Jeffrey D. (Technical Monitor); Pfeiffer, Neal J.; Christians, Joel G.

2005-01-01

During Phase I of this project, Raytheon Aircraft Company (RAC) has analytically and experimentally evaluated key components of a system that could be implemented for active tailoring of wing lift distribution using low-drag, trailing-edge modifications. Simple systems such as those studied by RAC could be used to enhance the cruise performance of a business jet configuration over a range of typical flight conditions. The trailing-edge modifications focus on simple, deployable mechanisms comprised of extendable small flap panels over portions of the span that could be used to subtly but positively optimize the lift and drag characteristics. The report includes results from low speed wind tunnel testing of the trailing-edge devices, descriptions of potential mechanisms for automation, and an assessment of the technology.
Embedded Wing Propulsion Conceptual Study

NASA Technical Reports Server (NTRS)

Kim, Hyun D.; Saunders, John D.

2003-01-01

As a part of distributed propulsion work under NASA's Revolutionary Aeropropulsion Concepts or RAC project, a new propulsion-airframe integrated vehicle concept called Embedded Wing Propulsion (EWP) is developed and examined through system and computational fluid dynamics (CFD) studies. The idea behind the concept is to fully integrate a propulsion system within a wing structure so that the aircraft takes full benefits of coupling of wing aerodynamics and the propulsion thrust stream. The objective of this study is to assess the feasibility of the EWP concept applied to large transport aircraft such as the Blended-Wing-Body aircraft. In this paper, some of early analysis and current status of the study are presented. In addition, other current activities of distributed propulsion under the RAC project are briefly discussed.
Cyclic Mechanical Loading Is Essential for Rac1-Mediated Elongation and Remodeling of the Embryonic Mitral Valve.

PubMed

Gould, Russell A; Yalcin, Huseyin C; MacKay, Joanna L; Sauls, Kimberly; Norris, Russell; Kumar, Sanjay; Butcher, Jonathan T

2016-01-11

During valvulogenesis, globular endocardial cushions elongate and remodel into highly organized thin fibrous leaflets. Proper regulation of this dynamic process is essential to maintain unidirectional blood flow as the embryonic heart matures. In this study, we tested how mechanosensitive small GTPases, RhoA and Rac1, coordinate atrioventricular valve (AV) differentiation and morphogenesis. RhoA activity and its regulated GTPase-activating protein FilGAP are elevated during early cushion formation but decreased considerably during valve remodeling. In contrast, Rac1 activity was nearly absent in the early cushions but increased substantially as the valve matured. Using gain- and loss-of-function assays, we determined that the RhoA pathway was essential for the contractile myofibroblastic phenotype present in early cushion formation but was surprisingly insufficient to drive matrix compaction during valve maturation. The Rac1 pathway was necessary to induce matrix compaction in vitro through increased cell adhesion, elongation, and stress fiber alignment. Facilitating this process, we found that acute cyclic stretch was a potent activator of RhoA and subsequently downregulated Rac1 activity via FilGAP. On the other hand, chronic cyclic stretch reduced active RhoA and downstream FilGAP, which enabled Rac1 activation. Finally, we used partial atrial ligation experiments to confirm in vivo that altered cyclic mechanical loading augmented or restricted cushion elongation and thinning, directly through potentiation of active Rac1 and active RhoA, respectively. Together, these results demonstrate that cyclic mechanical signaling coordinates the RhoA to Rac1 signaling transition essential for proper embryonic mitral valve remodeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enantioselective oxidative stress and oxidative damage caused by Rac- and S-metolachlor to Scenedesmus obliquus.

PubMed

Liu, Huijun; Xia, YiLu; Cai, Weidan; Zhang, Yina; Zhang, Xiaoqiang; Du, Shaoting

2017-04-01

The rational use and environmental security of chiral pesticides has gained the interest of many researchers. The enantioselective effects of Rac- and S-metolachlor on oxidative stress in Scenedesmus obliquus were determined in this study. Stronger green fluorescence was observed in response to S-metolachlor treatment than to Rac-metolachlor treatment, suggesting that more reactive oxygen species (ROS) were stimulated by S-metolachlor. ROS levels following S-metolachlor treatment were 1.92-, 8.31-, and 1.08-times higher than those observed following Rac-metolachlor treatment at 0.1, 0.2, and 0.3 mg/L, respectively. Superoxide dismutase (SOD) and catalase (CAT) were stimulated with increasing herbicide concentrations, with S-metolachlor exhibiting a greater effect. Oxidative damage in terms of chlorophyll (Chl) content, cellular membrane permeability, and cellular ultrastructures of S. obliquus were investigated. Chla and Chlb contents in algae treated with Rac-metolachlor were 2-6-fold higher than those in algae treated with S-metolachlor at 0.1, 0.2, and 0.3 mg/L. The cellular membrane permeability of algae exposed to 0.3 mg/L Rac- and S-metolachlor was 6.19- and 42.5-times that of the control. Correlation analysis implied that ROS are the major factor responsible for the oxidative damage caused by Rac- and S-metolachlor. Damage to the chloroplasts and cell membrane of S. obliquus, low production of starch granules, and an increased number of vacuoles were observed upon ultrastructural morphology analysis by transmission electron microscope. These results indicate that S-metolachlor has a greater effect on S. obliquus than Rac-metolachlor. Copyright © 2017 Elsevier Ltd. All rights reserved.
Screening of a Drug Library Identifies Inhibitors of Cell Intoxication by CNF1.

PubMed

Mahtal, Nassim; Brewee, Clémence; Pichard, Sylvain; Visvikis, Orane; Cintrat, Jean-Christophe; Barbier, Julien; Lemichez, Emmanuel; Gillet, Daniel

2018-04-06

Cytotoxic necrotizing factor 1 (CNF1) is a toxin produced by pathogenic strains of Escherichia coli responsible for extra-intestinal infections. CNF1 deamidates Rac1, thereby triggering its permanent activation and worsening inflammatory reactions. Activated Rac1 is prone to proteasomal degradation. There is no targeted therapy against CNF1, despite its clinical relevance. In this work we developed a fluorescent cell-based immunoassay to screen for inhibitors of CNF1-induced Rac1 degradation among 1120 mostly approved drugs. Eleven compounds were found to prevent CNF1-induced Rac1 degradation, and five also showed a protective effect against CNF1-induced multinucleation. Finally, lasalocid, monensin, bepridil, and amodiaquine protected cells from both diphtheria toxin and CNF1 challenges. These data highlight the potential for drug repurposing to fight several bacterial infections and Rac1-based diseases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
An R package for simulating growth and organic wastage in aquaculture farms in response to environmental conditions and husbandry practices

PubMed Central

Baldan, Damiano; Porporato, Erika Maria Diletta; Pastres, Roberto

2018-01-01

A new R software package, RAC, is presented. RAC allows to simulate the rearing cycle of 4 species, finfish and shellfish, highly important in terms of production in the Mediterranean Sea. The package works both at the scale of the individual and of the farmed population. Mathematical models included in RAC were all validated in previous works, and account for growth and metabolism, based on input data characterizing the forcing functions—water temperature, and food quality/quantity. The package provides a demo dataset of forcings for each species, as well as a typical set of husbandry parameters for Mediterranean conditions. The present work illustrates RAC main features, and its current capabilities/limitations. Three test cases are presented as a proof of concept of RAC applicability, and to demonstrate its potential for integrating different open products nowadays provided by remote sensing and operational oceanography. PMID:29723208
Density and refractive index data of binary and ternary mixtures of imidazolium-based ionic liquids, n-hexane and organic compounds involved in the kinetic resolution of rac-2-pentanol.

PubMed

Montalbán, Mercedes G; Collado-González, Mar; Lozano-Pérez, A Abel; Baños, F Guillermo Díaz; Víllora, Gloria

2018-08-01

This data article is related to the subject of the research article "Extraction of Organic Compounds Involved in the Kinetic Resolution of rac-2-Pentanol from n-Hexane by Imidazolium-based Ionic Liquids: Liquid-Liquid Equilibrium" (Montalbán et al., 2018) [1]. It contains experimental data of density and refractive index of binary and ternary mixtures of imidazolium-based ionic liquids, n -hexane and organic compounds involved in the kinetic resolution of rac -2-pentanol ( rac -2-pentanol, vinyl butyrate, rac -2-pentyl butyrate or butyric acid) measured at 303.15 K and 1 atm. These data are presented as calibration curves which help to determine the composition of the ionic liquid-rich phase knowing its density or refractive index.
A Meta-Analysis of Zilpaterol and Ractopamine Effects on Feedlot Performance, Carcass Traits and Shear Strength of Meat in Cattle

PubMed Central

Lean, Ian J.; Thompson, John M.; Dunshea, Frank R.

2014-01-01

This study is a meta-analysis of the effects of the beta-agonists zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RAC) on feedlot performance, carcase characteristics of cattle and Warner Bratzler shear force (WBSF) of muscles. It was conducted to evaluate the effect of the use of these agents on beef production and meat quality and to provide data that would be useful in considerations on the effect of these agents on meat quality in Meat Standards Australia evaluations. We conducted a comprehensive literature search and study assessment using PubMed, Google Scholar, ScienceDirect, Scirus, and CAB and identification of other studies from reference lists in papers and searches. Searches were based on the key words: zilpaterol, zilmax, ractopamine, optaflexx, cattle and beef. Studies from theses obtained were included. Data were extracted from more than 50 comparisons for both agents and analysed using meta-analysis and meta-regression. Both agents markedly increased weight gain, hot carcase weight and longissimus muscle area and increased the efficiency of gain:feed. These effects were particularly large for ZH, however, fat thickness was decreased by ZH, but not RAC. Zilpaterol also markedly increased WBSF by 1.2 standard deviations and more than 0.8 kg, while RAC increased WBSF by 0.43 standard deviations and 0.2 kg. There is evidence in the ZH studies, in particular, of profound re-partitioning of nutrients from fat to protein depots. This work has provided critically needed information on the effects of ZH and RAC on production, efficiency and meat quality. PMID:25548908
Comparative evaluation of three proliferation markers, Ki-67, TOP2A, and RacGAP1, in bronchopulmonary neuroendocrine neoplasms: Issues and prospects

PubMed Central

Neubauer, Elisa; Wirtz, Ralph M.; Kaemmerer, Daniel; Athelogou, Maria; Schmidt, Lydia; Sänger, Jörg; Lupp, Amelie

2016-01-01

The classification of bronchopulmonary neuroendocrine neoplasms (BP-NEN) into four tumor entities (typical carcinoids (TC), atypical carcinoids (AC), small cell lung cancers (SCLC), large cell neuroendocrine lung carcinomas (LCNEC)) is difficult to perform accurately, but important for prognostic statements and therapeutic management decisions. In this regard, we compared the expression of three proliferation markers, Ki-67, Topoisomerase II alpha (TOP2A), and RacGAP1, in a series of tumor samples from 104 BP-NEN patients (24 TC, 21 AC, 52 SCLC, 7 LCNEC) using different evaluation methods (immunohistochemistry (IHC): Average evaluation, Hotspot evaluation, digital image analysis; RT-qPCR). The results indicated that all three markers had increased protein and mRNA expression with poorer differentiation and correlated well with each other, as well as with grading, staging, and poor survival. Compared with Ki-67 and TOP2A, RacGAP1 allowed for a clearer prognostic statement. The cut-off limits obtained for Ki-67-Average (IHC) were TC-AC 1.5, AC-SCLC 19, and AC-LCNEC 23.5. The Hotspot evaluation generated equal to higher, the digital image analysis generally lower between-entity cut-off limits. All three markers enabled a clear-cut differentiation between the BP-NEN entities, and all methods evaluated were suitable for marker assessment. However, to define optimal cut-off limits, the Ki-67 evaluation methods should be standardized. RacGAP1 appeared to be a new marker with great potential. PMID:27259241
Identification of a Second Raccoon-Associated Polyomavirus

PubMed Central

Geoghegan, Eileen M.; Welch, Nicole L.; Yabsley, Michael J.; Church, Molly E.; Pesavento, Patricia A.

2017-01-01

ABSTRACT Raccoon polyomavirus 1 (RacPyV1) is the suspected cause of an outbreak of fatal brain tumors among raccoons (Procyon lotor) in the western United States. Spleen samples from Georgia raccoons were screened for polyomaviruses. Although RacPyV1 was not detected, a previously unknown polyomavirus, which we designate RacPyV2, was identified and sequenced. PMID:28663292
Impact of point mutation P29S in RAC1 on tumorigenesis.

PubMed

Rajendran, Vidya; Gopalakrishnan, Chandrasekhar; Purohit, Rituraj

2016-11-01

A point mutation (P29S) in the RAS-related C3 botulinum toxin substrate 1 (RAC1) was considered to be a trigger for melanoma, a form of skin cancer with highest mortality rate. In this study, we have investigated the pathogenic role of P29S based on the conformational behavior of RAC1 protein toward guanosine triphosphate (GTP). Molecular interaction, molecular dynamics trajectory analysis (RMSD, RMSF, Rg, SASA, DSSP, and PCA), and shape analysis of binding pocket were performed to analyze the interaction energy and the dynamic behavior of native and mutant RAC1 at the atomic level. Due to this mutation, the RAC1 switch I region acquired more flexibility and, to compensate it, the switch II region becomes rigid in their conformational space, as a result of which the interaction energy of the protein for GTP increased. The overall results strongly implied that the changes in atomic conformation of the switch I and II regions in mutant RAC1 protein were a significant reason for its malignant transformation and tumorigenesis. We raised the opportunity for researchers to design possible therapeutic molecule by considering our findings.
Rac1/RhoA antagonism defines cell-to-cell heterogeneity during epidermal morphogenesis in nematodes

PubMed Central

Ouellette, Marie-Hélène

2016-01-01

The antagonism between the GTPases Rac1 and RhoA controls cell-to-cell heterogeneity in isogenic populations of cells in vitro and epithelial morphogenesis in vivo. Its involvement in the regulation of cell-to-cell heterogeneity during epidermal morphogenesis has, however, never been addressed. We used a quantitative cell imaging approach to characterize epidermal morphogenesis at a single-cell level during early elongation of Caenorhabditis elegans embryos. This study reveals that a Rac1-like pathway, involving the Rac/Cdc42 guanine-exchange factor β-PIX/PIX-1 and effector PAK1/PAK-1, and a RhoA-like pathway, involving ROCK/LET-502, control the remodeling of apical junctions and the formation of basolateral protrusions in distinct subsets of hypodermal cells. In these contexts, protrusions adopt lamellipodia or an amoeboid morphology. We propose that lamella formation may reduce tension building at cell–cell junctions during morphogenesis. Cell-autonomous antagonism between these pathways enables cells to switch between Rac1- and RhoA-like morphogenetic programs. This study identifies the first case of cell-to-cell heterogeneity controlled by Rac1/RhoA antagonism during epidermal morphogenesis. PMID:27821782
Rac1/WAVE2 and Cdc42/N-WASP Participation in Actin-Dependent Host Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi.

PubMed

Bonfim-Melo, Alexis; Ferreira, Éden R; Mortara, Renato A

2018-01-01

This study evaluated the participation of host cell Rho-family GTPases and their effector proteins in the actin-dependent invasion by Trypanosoma cruzi extracellular amastigotes (EAs). We observed that all proteins were recruited and colocalized with actin at EA invasion sites in live or fixed cells. EA internalization was inhibited in cells depleted in Rac1, N-WASP, and WAVE2. Time-lapse experiments with Rac1, N-WASP and WAVE2 depleted cells revealed that EA internalization kinetics is delayed even though no differences were observed in the proportion of EA-induced actin recruitment in these groups. Overexpression of constitutively active constructs of Rac1 and RhoA altered the morphology of actin recruitments to EA invasion sites. Additionally, EA internalization was increased in cells overexpressing CA-Rac1 but inhibited in cells overexpressing CA-RhoA. WT-Cdc42 expression increased EA internalization, but curiously, CA-Cdc42 inhibited it. Altogether, these results corroborate the hypothesis of EA internalization in non-phagocytic cells by a phagocytosis-like mechanism and present Rac1 as the key Rho-family GTPase in this process.
Rac1/WAVE2 and Cdc42/N-WASP Participation in Actin-Dependent Host Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi

PubMed Central

Bonfim-Melo, Alexis; Ferreira, Éden R.; Mortara, Renato A.

2018-01-01

This study evaluated the participation of host cell Rho-family GTPases and their effector proteins in the actin-dependent invasion by Trypanosoma cruzi extracellular amastigotes (EAs). We observed that all proteins were recruited and colocalized with actin at EA invasion sites in live or fixed cells. EA internalization was inhibited in cells depleted in Rac1, N-WASP, and WAVE2. Time-lapse experiments with Rac1, N-WASP and WAVE2 depleted cells revealed that EA internalization kinetics is delayed even though no differences were observed in the proportion of EA-induced actin recruitment in these groups. Overexpression of constitutively active constructs of Rac1 and RhoA altered the morphology of actin recruitments to EA invasion sites. Additionally, EA internalization was increased in cells overexpressing CA-Rac1 but inhibited in cells overexpressing CA-RhoA. WT-Cdc42 expression increased EA internalization, but curiously, CA-Cdc42 inhibited it. Altogether, these results corroborate the hypothesis of EA internalization in non-phagocytic cells by a phagocytosis-like mechanism and present Rac1 as the key Rho-family GTPase in this process. PMID:29541069
Systemic and bronchodilator effects of inhaled rac-formoterol in subjects with chronic obstructive pulmonary disease: a dose–response study

PubMed Central

Whale, Christopher I; Sovani, Milind P; Mortimer, Kevin J; Harrison, Timothy W; Tattersfield, Anne E

2008-01-01

AIMS Rac-formoterol is effective as maintenance treatment for both asthma and chronic obstructive pulmonary disease (COPD) and is now used as relief therapy in asthma. Using rac-formoterol for relief and maintenance treatment could involve inhalation of high doses, and whether this is of benefit in COPD is uncertain. Our aim was to determine whether higher doses of inhaled rac-formoterol produce systemic adverse effects that outweigh the limited bronchodilator benefit seen in subjects with COPD. METHODS We examined airway and systemic effects of 6, 12, 24 and 48 μg rac-formoterol and placebo on separate days in 20 subjects with symptomatic COPD [forced expiratory volume in 1 s (FEV1) 47% predicted]. FEV1, oxygen saturation, dyspnoea, 6-min walk distance, patient satisfaction and systemic effects were measured and treatment was assessed against placebo and for dose–response effects. RESULTS FEV1[area under the time–response curve (AUC)] and satisfaction scores increased with all formoterol doses compared with placebo, as did AUC tremor with the 24- and 48-μg doses and AUC heart rate with the 48-μg dose. A dose–response relationship was seen with FEV1 and tremor, but not with satisfaction scores. There was no difference between placebo and rac-formoterol for other variables. CONCLUSIONS Our results show that in patients with COPD rac-formoterol improves FEV1 and patient satisfaction without a corresponding reduction in dyspnoea. Since the systemic effects from a relatively high dose were minimal, its use as relief medication in COPD merits further evaluation. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT The long-acting inhaled β2-agonist formoterol has systemic effects when taken in high doses. It can be used as relief medication in asthma and there is interest in this approach in chronic obstructive pulmonary disease (COPD). Relief medication can involve high doses, and in subjects with COPD who have limited ability to bronchodilate the adverse effects can outweigh the benefits. There are concerns with the overall safety of high-dose β2-agonists in subjects with COPD, and this study looks at the balance of beneficial and adverse effects of a range of doses of inhaled formoterol. WHAT THIS STUDY ADDS Among subjects with COPD, high-dose inhaled formoterol produced a dose-related increase in forced expiratory volume in 1 s without a corresponding reduction in dyspnoea or increase in walk distance.Systemic effects were modest, however, and high doses did not appear to reduce patient satisfaction.Although further safety data are needed, inhaled formoterol may have a role as relief medication in COPD. PMID:18394012
Collective cell migration of thyroid carcinoma cells: a beneficial ability to override unfavourable substrates.

PubMed

Lobastova, Liudmila; Kraus, Dominik; Glassmann, Alexander; Khan, Dilaware; Steinhäuser, Christian; Wolff, Christina; Veit, Nadine; Winter, Jochen; Probstmeier, Rainer

2017-02-01

Tumor cell invasion and metastasis are life threatening events. Invasive tumor cells tend to migrate as collective sheets. In the present in vitro study we aimed to (i) assess whether collective tumor cells gain benefits in their migratory potential compared to single cells and (ii) to identify its putative underlying molecular mechanisms. The migratory potential of single and collective carcinoma cells was assessed using video time lapse microscopy and cell migration assays in the absence and presence of seven potential gap junction inhibitors or the Rac1 inhibitor Z62954982. The perturbation of gap junctions was assessed using a dye diffusion assay. In addition, LDH-based cytotoxicity and RT-PCR-based expression analyses were performed. Whereas single breast, cervix and thyroid carcinoma cells were virtually immobile on unfavourable plastic surfaces, we found that they gained pronounced migratory capacities as collectives under comparable conditions. Thyroid carcinoma cells, that were studied in more detail, were found to express specific subsets of connexins and to form active gap junctions as revealed by dye diffusion analysis. Although all potential gap junction blockers suppressed intercellular dye diffusion in at least one of the cell lines tested, only two of them were found to inhibit collective cell migration and none of them to inhibit single cell migration. In the presence of the Rac1 inhibitor Z62954982 collective migration, but not single cell migration, was found to be reduced up to 20 %. Our data indicate that collective migration enables tumor cells to cross otherwise unfavourable substrate areas. This capacity seems to be independent of intercellular communication via gap junctions, whereas Rac1-dependent intracellular signalling seems to be essential.
Analysis of a minimal Rho-GTPase circuit regulating cell shape

NASA Astrophysics Data System (ADS)

Holmes, William R.; Edelstein-Keshet, Leah

2016-08-01

Networks of Rho-family GTPases regulate eukaryotic cell polarization and motility by controlling assembly and contraction of the cytoskeleton. The mutually inhibitory Rac-Rho circuit is emerging as a central, regulatory hub that can affect the shape and motility phenotype of eukaryotic cells. Recent experimental manipulation of the amounts of Rac and Rho or their regulators (guanine nucleotide-exchange factors, GTPase-activating proteins, guanine nucleotide dissociation inhibitors) have been shown to bias the prevalence of these different states and promote transitions between them. Here we show that part of this data can be understood in terms of inherent Rac-Rho mutually inhibitory dynamics. We analyze a spatio-temporal mathematical model of Rac-Rho dynamics to produce a detailed set of predictions of how parameters such as GTPase rates of activation and total amounts affect cell decisions (such as Rho-dominated contraction, Rac-dominated spreading, and spatially segregated Rac-Rho polarization). We find that in some parameter regimes, a cell can take on any of these three fates depending on its environment or stimuli. We also predict how experimental manipulations (corresponding to parameter variations) can affect cell shapes observed. Our methods are based on local perturbation analysis (a kind of nonlinear stability analysis), and an approximation of nonlinear feedback by sharp switches. We compare the Rac-Rho model to an even simpler single-GTPase (‘wave-pinning’) model and demonstrate that the overall behavior is inherent to GTPase properties, rather than stemming solely from network topology.
Inhibition of GTPase Rac1 in endothelium by 6-mercaptopurine results in immunosuppression in nonimmune cells: new target for an old drug.

PubMed

Marinković, Goran; Kroon, Jeffrey; Hoogenboezem, Mark; Hoeben, Kees A; Ruiter, Matthijs S; Kurakula, Kondababu; Otermin Rubio, Iker; Vos, Mariska; de Vries, Carlie J M; van Buul, Jaap D; de Waard, Vivian

2014-05-01

Azathioprine and its metabolite 6-mercaptopurine (6-MP) are well established immunosuppressive drugs. Common understanding of their immunosuppressive properties is largely limited to immune cells. However, in this study, the mechanism underlying the protective role of 6-MP in endothelial cell activation is investigated. Because 6-MP and its derivative 6-thioguanosine-5'-triphosphate (6-T-GTP) were shown to block activation of GTPase Rac1 in T lymphocytes, we focused on Rac1-mediated processes in endothelial cells. Indeed, 6-MP and 6-T-GTP decreased Rac1 activation in endothelial cells. As a result, the compounds inhibited TNF-α-induced downstream signaling via JNK and reduced activation of transcription factors c-Jun, activating transcription factor-2 and, in addition, NF κ-light-chain-enhancer of activated B cells (NF-κB), which led to decreased transcription of proinflammatory cytokines. Moreover, 6-MP and 6-T-GTP selectively decreased TNF-α-induced VCAM-1 but not ICAM-1 protein levels. Rac1-mediated generation of cell membrane protrusions, which form docking structures to capture leukocytes, also was reduced by 6-MP/6-T-GTP. Consequently, leukocyte transmigration was inhibited after 6-MP/6-T-GTP treatment. These data underscore the anti-inflammatory effect of 6-MP and 6-T-GTP on endothelial cells by blocking Rac1 activation. Our data provide mechanistic insight that supports development of novel Rac1-specific therapeutic approaches against chronic inflammatory diseases.
Quercetin protects liver injury induced by bile duct ligation via attenuation of Rac1 and NADPH oxidase1 expression in rats.

PubMed

Kabirifar, Razieh; Ghoreshi, Zohreh-Al-Sadat; Safari, Fatemeh; Karimollah, Alireza; Moradi, Ali; Eskandari-Nasab, Ebrahim

2017-02-01

Bile duct ligation (BDL) and subsequent cholestasis are correlated with oxidative stress, hepatocellular injury and fibrosis. Quercetin is a flavonoid with antifibrotic, and hepatoprotective properties. However, the molecular mechanism underlying quercetin-mediated hepatoprotection is not fully understood. The current study was to evaluate mechanisms of hepatoprotective effect of quercetin in BDL rat model. We divided male Wistar rats into 4 groups (n=8 for each): sham, sham+quercetin (30 mg/kg per day), BDL, and BDL+quercetin (30 mg/kg per day). Four weeks later, the rats were sacrificed, the blood was collected for liver enzyme measurements and liver for the measurement of Rac1, Rac1-GTP and NOX1 mRNA and protein levels by quantitative PCR and Western blotting, respectively. Quercetin significantly alleviated liver injury in BDL rats as evidenced by histology and reduced liver enzymes. Furthermore, the mRNA and protein expression of Rac1, Rac1-GTP and NOX1 were significantly increased in BDL rats compared with those in the sham group (P<0.05); quercetin treatment reversed these variables back toward normal (P<0.05). Another interesting finding was that the antioxidant markers e.g. superoxide dismutase and catalase were elevated in quercetin-treated BDL rats compared to BDL rats (P<0.05). Quercetin demonstrated hepatoprotective activity against BDL-induced liver injury through increasing antioxidant capacity of the liver tissue, while preventing the production of Rac1, Rac1-GTP and NOX1 proteins.
Effect of ractopamine and sex on growth, carcass characteristics, processing yield, and meat quality characteristics of crossbred swine.

PubMed

Uttaro, B E; Ball, R O; Dick, P; Rae, W; Vessie, G; Jeremiah, L E

1993-09-01

One hundred twenty-eight 64-kg crossbred barrows and gilts were administered either 0 or 20 ppm of Ractopamine (RAC) in a pelleted corn-soybean meal diet that contained either 17.5 or 19.6% CP. Carcass quality was evaluated after slaughter at 100 kg. Dietary protein levels produced few significant effects; therefore, data were pooled for analysis. Pigs fed RAC exhibited improvement in feed efficiency (P < .01), ADG (P < .01), and number of days to slaughter (P < .01). Pigs fed RAC had 1.8 mm less fat (P < .05) and 3.4 mm more lean (P < .01) at the grading probe site. Gilts had 4.9 mm less fat than barrows at the probe site (P < .01) and also yielded an estimated 4.1% more lean (P < .01). Trimmed loins and bellies of animals fed 20 ppm of RAC were 230 g heavier (P < .05) than those of animals fed the control diet. Trimmed loins from gilts were 260 g heavier (P < .05), whereas barrows produced bellies that were 490 g heavier (P < .05) than those of gilts. The yield of processed ham was greater from both pigs fed RAC (P < .01) and barrows (P < .05). Loins of pigs fed RAC had lower cooking loss (P < .05), greater Warner-Bratzler shear value (P < .05), and higher fragmentation index value (P < .01). Although effects of sex were similar to or greater than the effects of 20 ppm of RAC, these effects were additive.
Rac-WAVE2 signaling is involved in the invasive and metastatic phenotypes of murine melanoma cells.

PubMed

Kurisu, Shusaku; Suetsugu, Shiro; Yamazaki, Daisuke; Yamaguchi, Hideki; Takenawa, Tadaomi

2005-02-17

WAVEs (WASP-family verprolin-homologous proteins) regulate the actin cytoskeleton through activation of Arp2/3 complex. As cell motility is regulated by actin cytoskeleton rearrangement and is required for tumor invasion and metastasis, blocking actin polymerization may be an effective strategy to prevent tumor dissemination. We show that WAVEs, especially WAVE2, are essential for invasion and metastasis of melanoma cells. Malignant B16F10 mouse melanoma cells expressed more WAVE1 and WAVE2 proteins and showed higher Rac activity than B16 parental cells, which are neither invasive nor metastatic. The effect of WAVE2 silencing by RNA interference (RNAi) on the highly invasive nature of B16F10 cells was more dramatic than that of WAVE1 RNAi. Membrane ruffling, cell motility, invasion into the extracellular matrix, and pulmonary metastasis of B16F10 cells were suppressed by WAVE2 RNAi. WAVE2 RNAi also had a profound effect on invasion induced by a constitutively active form of Rac (RacCA). In addition, ectopic expression of both RacCA and WAVE2 in B16 cells resulted in further increase in the invasiveness than that observed in B16 cells expressing only RacCA. Thus, WAVE2 acts as the primary effector downstream of Rac to achieve invasion and metastasis, suggesting that suppression of WAVE2 activity holds a promise for preventing cancer invasion and metastasis.
Role of Rac1/WAVE2 Signaling in Mediating the Inhibitory Effects of γ-Tocotrienol on Mammary Cancer Cell Migration and Invasion.

PubMed

Algayadh, Ibrahim Gayadh; Dronamraju, Venkateshwararao; Sylvester, Paul William

2016-01-01

The majority of breast cancer deaths result from the progression of this disease to a metastatic phenotype. Rac1 and Cdc42 are Rho family members that together with their downstream effectors, Wiskott-Aldrich Syndrome protein-family verprolin-homologous protein 2 (WAVE2) and Arp2/3, play an important role in cytoskeletal reorganization and the formation of membrane protrusions that promote cancer cell migration and invasion. γ-Tocotrienol, is a natural isoform within the vitamin E family of compounds that inhibits breast cancer cell growth and progression by suppressing various signaling pathways involved in mitogenic signaling and metastatic progression. Studies were conducted to examine the effects of γ-tocotrienol on Rac1/WAVE2 signaling dependent migration and invasion in highly metastatic mouse +SA and human MDA-MB-231 mammary cancer cells. Exposure to γ-tocotrienol resulted in a dose-responsive decrease in Rac1/WAVE2 signaling as characterized by a suppression in the levels of Rac1/Cdc42, phospho-Rac1/Cdc42, WAVE2, Arp2, and Arp3 expression. Additional studies also demonstrated that similar treatment with γ-tocotrienol resulted in a significant reduction in tumor cell migration and invasion. Taken together, these findings indicate that γ-tocotrienol treatment effectively inhibits Rac1/WAVE2 signaling and reduces metastatic phenotypic expression in mammary cancer cells, suggesting that γ-tocotrienol may provide some benefit as a novel therapeutic approach in the treatment of metastatic breast cancer.
Fractionation profile and mobility pattern of metals in sediments from the Mediterranean Coast, Libya.

PubMed

Nasr, Samir M; Okbah, Mohamed A; El Haddad, Huda S; Soliman, Naglaa F

2015-07-01

A five-step sequential extraction technique, following Tessier's protocol, has been applied to determine the chemical association of Cd, Cu, Fe, Pb, and Zn with major sedimentary phases (exchangeable, carbonate, manganese and iron oxides, organic and residual fraction) in surface sediments from 14 stations off the Libyan Mediterranean coast. This study is a first approach of chemical fractionation of these metals in one of the most economically important area of the Libyan coastline in Mediterranean Sea. The total metal content was also determined. The total concentration of metals ranged from 5-10.5 mg/kg for Cd, 9.1-22.7 mg/kg for Cu, 141.8-1056.8 mg/kg for Fe, 18.9-56.9 mg/kg for Pb, and 11.6-30.5 mg/kg for Zn. The results of the partitioning study showed that the residual form was the dominant fraction of the selected metals among most of the studied locations. The degree of surface sediment contamination was computed for risk assessment code (RAC), individual contamination factor (ICF), and Global contamination factor (GCF). Risk assessment code classification showed that the relative amounts of easily dissolved phase of trace metals in the sediments are in the order of Pb>Zn>Cd>Cu>Fe. The results of ICF and GCF showed that Sirt and Abu Kammashand had higher GCF than other sites indicating higher environmental risk. In terms of ICF value, a decrease order in environmental risk by trace metals was Pb>Zn>Cu>Cd>Fe. Therefore, Pb had highest risk to water body.

Identification of a Second Raccoon-Associated Polyomavirus.

PubMed

Geoghegan, Eileen M; Welch, Nicole L; Yabsley, Michael J; Church, Molly E; Pesavento, Patricia A; Buck, Christopher B

2017-06-29

Raccoon polyomavirus 1 (RacPyV1) is the suspected cause of an outbreak of fatal brain tumors among raccoons ( Procyon lotor ) in the western United States. Spleen samples from Georgia raccoons were screened for polyomaviruses. Although RacPyV1 was not detected, a previously unknown polyomavirus, which we designate RacPyV2, was identified and sequenced. Copyright © 2017 Geoghegan et al.
Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Gongming; Shen, Nan; Jiang, Xuefeng

2016-01-15

The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferationmore » (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.« less
Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Xionggao; Department of Ophthalmology, Hainan Medical College, Haikou; Wei, Yantao

2012-03-09

Highlights: Black-Right-Pointing-Pointer Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. Black-Right-Pointing-Pointer Rac1 is activated in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells inducedmore » by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that vitreous-transformed human RPE cells undergo cytoskeletal rearrangements via Rac1 GTPase-dependent pathways that modulate LIMK1 and cofilin activity. The TGF{beta}-like activity of the vitreous may participate in this effect. Actin polymerization causes the cytoskeletal rearrangements that lead to the plasticity of vitreous-transformed RPE cells in PVR.« less
Rac-1 as a new therapeutic target in cerebro- and cardio-vascular diseases.

PubMed

Carrizzo, Albino; Forte, Maurizio; Lembo, Maria; Formisano, Luigi; Puca, Annibale A; Vecchione, Carmine

2014-01-01

Growing evidence indicates that overproduction of reactive oxygen species (ROS) plays a prominent role in the development of cardio- and cerebro-vascular diseases. Among the mechanisms identified to produce oxidative stress in the vascular wall, those mediated by membrane-bound NAD(P)H oxidases represent a major one. NAD(P)H oxidases are a family of enzymes that generate ROS both in phagocytic and non-phagocytic cell types. Vascular NAD(P)H oxidase contains the membrane-bound subunits Nox1, Nox2 (gp91phox), Nox4 and p22phox, the catalytic site of the oxidase, and the cytosolic components p47phox and p67phox. Rac1 (Ras-related C3 botulinum toxin substrate1) is a small GTPase essential for the assembly and activation of NADPH oxidase. Several molecular and cellular studies have reported the involvement of Rac1 in different cardiovascular pathologies, such as vascular smooth muscle proliferation, cardiomyocyte hypertrophy, endothelial cell shape change, atherosclerosis and endothelial dysfunction in hypertension. In addition, increased activation of NADPH oxidase by Rac1 has been reported in animals and humans after myocardial infarction and heart failure. The Rac1/NADPH pathway has also been found involved in different pathologies of the cerebral district, such as ischemic stroke, cognitive impairment, subaracnoid hemorrhage and neuronal oxidative damage typical of several neurodegenerative disorders. In addition, thrombotic events are an important step in the onset of cardio- and cerebrovascular diseases. Rac1 has been found involved also in platelet activation, inducing actin polymerization and lamellipodia formation, which are necessary steps for platelet aggregation. Taken together, the evidence candidates Rac1 as a new pharmacological target of cardiovascular and cerebrovascular diseases. Although the involvement of Rac1 in the beneficial pleiotropic effects of drugs such as statins is well known, and the onset of numerous side effects has raised concern for the management of some patient groups. Interestingly, a novel selective Rac1 inhibitor, NSC23766, has recently been introduced; its use has been reported mainly in the oncology field. Future studies are needed to extend its application to cardio- and cerebro-vascular diseases, and translate its use to humans.
Rac1 and Cdc42 GTPases regulate shear stress-driven β-catenin signaling in osteoblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan, Qiaoqiao; Cho, Eunhye; Yokota, Hiroki

2013-04-19

Highlights: •Shear stress increased TCF/LEF activity and stimulated β-catenin nuclear localization. •Rac1, Cdc42, and RhoA displayed distinct dynamic activity patterns under flow. •Rac1 and Cdc42, but not RhoA, regulate shear stress-driven TCF/LEF activation. •Cytoskeleton did not significantly affect shear stress-induced TCF/LEF activation. -- Abstract: Beta-catenin-dependent TCF/LEF (T-cell factor/lymphocyte enhancing factor) is known to be mechanosensitive and an important regulator for promoting bone formation. However, the functional connection between TCF/LEF activity and Rho family GTPases is not well understood in osteoblasts. Herein we investigated the molecular mechanisms underlying oscillatory shear stress-induced TCF/LEF activity in MC3T3-E1 osteoblast cells using live cell imaging.more » We employed fluorescence resonance energy transfer (FRET)-based and green fluorescent protein (GFP)-based biosensors, which allowed us to monitor signal transduction in living cells in real time. Oscillatory (1 Hz) shear stress (10 dynes/cm{sup 2}) increased TCF/LEF activity and stimulated translocation of β-catenin to the nucleus with the distinct activity patterns of Rac1 and Cdc42. The shear stress-induced TCF/LEF activity was blocked by the inhibition of Rac1 and Cdc42 with their dominant negative mutants or selective drugs, but not by a dominant negative mutant of RhoA. In contrast, constitutively active Rac1 and Cdc42 mutants caused a significant enhancement of TCF/LEF activity. Moreover, activation of Rac1 and Cdc42 increased the basal level of TCF/LEF activity, while their inhibition decreased the basal level. Interestingly, disruption of cytoskeletal structures or inhibition of myosin activity did not significantly affect shear stress-induced TCF/LEF activity. Although Rac1 is reported to be involved in β-catenin in cancer cells, the involvement of Cdc42 in β-catenin signaling in osteoblasts has not been identified. Our findings in this study demonstrate that both Rac1 and Cdc42 GTPases are critical regulators in shear stress-driven β-catenin signaling in osteoblasts.« less
Small G Rac1 is involved in replication cycle of dengue serotype 2 virus in EAhy926 cells via the regulation of actin cytoskeleton.

PubMed

Zhang, Jing; Wu, Na; Gao, Na; Yan, Wenli; Sheng, Ziyang; Fan, Dongying; An, Jing

2016-05-01

Bleeding is a clinical characteristic of severe dengue and may be due to increased vascular permeability. However, the pathogenesis of severe dengue remains unclear. In this study, we showed that the Rac1-microfilament signal pathway was involved in the process of DENV serotype 2 (DENV2) infection in EAhy926 cells. DENV2 infection induced dynamic changes in actin organization, and treatment with Cytochalasin D or Jasplakinolide disrupted microfilament dynamics, reduced DENV2 entry, and inhibited DENV2 assembly and maturation. Rac1 activities decreased during the early phase and gradually increased by the late phase of infection. Expression of the dominant-negative form of Rac1 promoted DENV2 entry but inhibited viral assembly, maturation and release. Our findings demonstrated that Rac1 plays an important role in the DENV2 life cycle by regulating actin reorganization in EAhy926 cells. This finding provides further insight into the pathogenesis of severe dengue.
Nuclear localization of coactivator RAC3 is mediated by a bipartite NLS and importin {alpha}3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeung, Percy Luk; Zhang, Aihua; Chen, J. Don

2006-09-15

The nuclear receptor coactivator RAC3 (also known as SRC-3/ACTR/AIB1/p/CIP/TRAM-1) belongs to the p160 coactivator family, which are involved in several physiological processes and diseases. Here we have investigated how RAC3 is translocated into the nucleus and show that it is mediated through a bipartite NLS and importin {alpha}3. This bipartite NLS is located within the conserved bHLH domain, and its mutation abolished nuclear localization. The NLS is also sufficient to cause nuclear import of EGFP, and the activity requires basic amino acids within the NLS. RAC3 binds strongly to importin {alpha}3, which also depends on the basic amino acids. Functionally,more » RAC3 cytoplasmic mutant loses its ability to enhance transcription, suggesting that nuclear localization is essential for coactivator function. Together, these results reveal a previous unknown mechanism for nuclear translocation of p160 coactivators and a critical function of the conserved bHLH within the coactivator.« less
The regulation of vascular endothelial growth factor-induced microvascular permeability requires Rac and reactive oxygen species.

PubMed

Monaghan-Benson, Elizabeth; Burridge, Keith

2009-09-18

Vascular permeability is a complex process involving the coordinated regulation of multiple signaling pathways in the endothelial cell. It has long been documented that vascular endothelial growth factor (VEGF) greatly enhances microvascular permeability; however, the molecular mechanisms controlling VEGF-induced permeability remain unknown. Treatment of microvascular endothelial cells with VEGF led to an increase in reactive oxygen species (ROS) production. ROS are required for VEGF-induced permeability as treatment with the free radical scavenger, N-acetylcysteine, inhibited this effect. Additionally, treatment with VEGF caused ROS-dependent tyrosine phosphorylation of both vascular-endothelial (VE)-cadherin and beta-catenin. Rac1 was required for the VEGF-induced increase in permeability and adherens junction protein phosphorylation. Knockdown of Rac1 inhibited VEGF-induced ROS production consistent with Rac lying upstream of ROS in this pathway. Collectively, these data suggest that VEGF leads to a Rac-mediated generation of ROS, which, in turn, elevates the tyrosine phosphorylation of VE-cadherin and beta-catenin, ultimately regulating adherens junction integrity.
STEF/TIAM2-mediated Rac1 activity at the nuclear envelope regulates the perinuclear actin cap.

PubMed

Woroniuk, Anna; Porter, Andrew; White, Gavin; Newman, Daniel T; Diamantopoulou, Zoi; Waring, Thomas; Rooney, Claire; Strathdee, Douglas; Marston, Daniel J; Hahn, Klaus M; Sansom, Owen J; Zech, Tobias; Malliri, Angeliki

2018-05-29

The perinuclear actin cap is an important cytoskeletal structure that regulates nuclear morphology and re-orientation during front-rear polarisation. The mechanisms regulating the actin cap are currently poorly understood. Here, we demonstrate that STEF/TIAM2, a Rac1 selective guanine nucleotide exchange factor, localises at the nuclear envelope, co-localising with the key perinuclear proteins Nesprin-2G and Non-muscle myosin IIB (NMMIIB), where it regulates perinuclear Rac1 activity. We show that STEF depletion reduces apical perinuclear actin cables (a phenotype rescued by targeting active Rac1 to the nuclear envelope), increases nuclear height and impairs nuclear re-orientation. STEF down-regulation also reduces perinuclear pMLC and decreases myosin-generated tension at the nuclear envelope, suggesting that STEF-mediated Rac1 activity regulates NMMIIB activity to promote stabilisation of the perinuclear actin cap. Finally, STEF depletion decreases nuclear stiffness and reduces expression of TAZ-regulated genes, indicating an alteration in mechanosensing pathways as a consequence of disruption of the actin cap.
Son of sevenless directly links the Robo receptor to rac activation to control axon repulsion at the midline.

PubMed

Yang, Long; Bashaw, Greg J

2006-11-22

Son of sevenless (Sos) is a dual specificity guanine nucleotide exchange factor (GEF) that regulates both Ras and Rho family GTPases and thus is uniquely poised to integrate signals that affect both gene expression and cytoskeletal reorganization. Here, using genetics, biochemistry, and cell biology, we demonstrate that Sos is recruited to the plasma membrane, where it forms a ternary complex with the Roundabout receptor and the SH3-SH2 adaptor protein Dreadlocks (Dock) to regulate Rac-dependent cytoskeletal rearrangement in response to the Slit ligand. Intriguingly, the Ras and Rac-GEF activities of Sos can be uncoupled during Robo-mediated axon repulsion; Sos axon guidance function depends on its Rac-GEF activity, but not its Ras-GEF activity. These results provide in vivo evidence that the Ras and RhoGEF domains of Sos are separable signaling modules and support a model in which Robo recruits Sos to the membrane via Dock to activate Rac during midline repulsion.
Rac1 Guides Porf-2 to Wnt Pathway to Mediate Neural Stem Cell Proliferation

PubMed Central

Yang, Xi-Tao; Huang, Guo-Hui; Li, Hong-Jiang; Sun, Zhao-Liang; Xu, Nan-Jie; Feng, Dong-Fu

2017-01-01

The molecular and cellular mechanisms underlying the anti-proliferative effects of preoptic regulator factor 2 (Porf-2) on neural stem cells (NSCs) remain largely unknown. Here, we found that Porf-2 inhibits the activity of ras-related C3 botulinum toxin substrate 1 (Rac1) protein in hippocampus-derived rat NSCs. Reduced Rac1 activity impaired the nuclear translocation of β-catenin, ultimately causing a repression of NSCs proliferation. Porf-2 knockdown enhanced NSCs proliferation but not in the presence of small molecule inhibitors of Rac1 or Wnt. At the same time, the repression of NSCs proliferation caused by Porf-2 overexpression was counteracted by small molecule activators of Rac1 or Wnt. By using a rat optic nerve crush model, we observed that Porf-2 knockdown enhanced the recovery of visual function. In particular, optic nerve injury in rats led to increased Wnt family member 3a (Wnt3a) protein expression, which we found responsible for enhancing Porf-2 knockdown-induced NSCs proliferation. These findings suggest that Porf-2 exerts its inhibitory effect on NSCs proliferation via Rac1-Wnt/β-catenin pathway. Porf-2 may therefore represent and interesting target for optic nerve injury recovery and therapy. PMID:28626389
A role for POR1, a Rac1-interacting protein, in ARF6-mediated cytoskeletal rearrangements.

PubMed Central

D'Souza-Schorey, C; Boshans, R L; McDonough, M; Stahl, P D; Van Aelst, L

1997-01-01

The ARF6 GTPase, the least conserved member of the ADP ribosylation factor (ARF) family, associates with the plasma membrane and intracellular endosome vesicles. Mutants of ARF6 defective in GTP binding and hydrolysis have a marked effect on endocytic trafficking and the gross morphology of the peripheral membrane system. Here we report that expression of the GTPase-defective mutant of ARF6, ARF6(Q67L), remodels the actin cytoskeleton by inducing actin polymerization at the cell periphery. This cytoskeletal rearrangement was inhibited by co-expression of ARF6(Q67L) with deletion mutants of POR1, a Rac1-interacting protein involved in membrane ruffling, but not with the dominant-negative mutant of Rac1, Rac1(S17N). A synergistic effect between POR1 and ARF6 for the induction of actin polymerization was detected. Furthermore, we observed that ARF6 interacts directly with POR1 and that this interaction was GTP dependent. These findings indicate that ARF6 and Rac1 function on distinct signaling pathways to mediate cytoskeletal reorganization, and suggest a role for POR1 as an important regulatory element in orchestrating cytoskeletal rearrangements at the cell periphery induced by ARF6 and Rac1. PMID:9312003
Novel insights into a retinoic-acid-induced cleft palate based on Rac1 regulation of the fibronectin arrangement.

PubMed

Tang, Qinghuang; Li, Liwen; Lee, Min-Jung; Ge, Qing; Lee, Jong-Min; Jung, Han-Sung

2016-03-01

Retinoic acid (RA)-induced cleft palate results from both extrinsic obstructions by the tongue and internal factors within the palatal shelves. Our previous study showed that the spatiotemporal expression of Rac1 regulates the fibronectin (FN) arrangement through cell density alterations that play an important role in palate development. In this study, we investigate the involvement of the Rac1 regulation of the FN arrangement in RA-induced cleft palate. Our results demonstrate that RA-induced intrinsic alterations in palatal shelves, including a delayed progress of cell condensation, delay palate development, even after the removal of the tongue. Further analysis shows that RA treatment diminishes the region-distinctive expression of Rac1 within the palatal shelves, which reversely alters the fibrillar arrangement of FN. Furthermore, RA treatment disrupts the formation of lamellipodia, which are indicative structures of cell migration that are regulated by Rac1. These results suggest that the Rac1 regulation of the FN arrangement is involved in RA-induced cleft palate through the regulation of cell migration, which delays the progress of cell condensation and subsequently influences the FN arrangement, inducing a delay in palate development. Our study provides new insights into the RA-induced impairment of palatal shelf elevation based on cell migration dynamics.
Comparison of 2-3D convection models with parameterized thermal evolution models: Application to Mars

NASA Astrophysics Data System (ADS)

Thiriet, M.; Plesa, A. C.; Breuer, D.; Michaut, C.

2017-12-01

To model the thermal evolution of terrestrial planets, 1D parametrized models are often used as 2 or 3D mantle convection codes are very time-consuming. In these parameterized models, scaling laws that describe the convective heat transfer rate as a function of the convective parameters are derived from 2-3D steady state convection models. However, so far there has been no comprehensive comparison whether they can be applied to model the thermal evolution of a cooling planet. Here we compare 2D and 3D thermal evolution models in the stagnant lid regime with 1D parametrized models and use parameters representing the cooling of the Martian mantle. For the 1D parameterized models, we use the approach of Grasset and Parmentier (1998) and treat the stagnant lid and the convecting layer separately. In the convecting layer, the scaling law for a fluid with constant viscosity is valid with Nu (Ra/Rac) ?, with Rac the critical Rayleigh number at which the thermal boundary layers (TBL) - top or bottom - destabilize. ? varies between 1/3 and 1/4 depending on the heating mode and previous studies have proposed intermediate values of b 0.28-0.32 according to their model set-up. The base of the stagnant lid is defined by the temperature at which the mantle viscosity has increased by a factor of 10; it thus depends on the rate of viscosity change with temperature multiplied by a factor? , whose value appears to vary depending on the geometry and convection conditions. In applying Monte Carlo simulations, we search for the best fit to temperature profiles and heat flux using three free parameters, i.e. ? of the upper TBL, ? and the Rac of the lower TBL. We find that depending on the definition of the stagnant lid thickness in the 2-3D models several combinations of ? and ? for the upper TBL can retrieve suitable fits. E.g. combinations of ? = 0.329 and ? = 2.19 but also ? = 0.295 and ? = 2.97 are possible; Rac of the lower TBL is 10 for all best fits. The results show that although the heating conditions change from bottom to mainly internally heating as a function of time, the thermal evolution can be represented by one set of parameters.
Upregulation of S1P1 and Rac1 receptors in the pulmonary vasculature of nitrofen-induced congenital diaphragmatic hernia.

PubMed

Zimmer, Julia; Takahashi, Toshiaki; Duess, Johannes W; Hofmann, Alejandro D; Puri, Prem

2016-02-01

Sphingolipids play a crucial role in pulmonary development. The sphingosine kinase 1 (SphK1) modulates the synthesis of sphingolipid sphingosine-1-phosphate (S1P). S1P regulates cell proliferation and angiogenesis via different receptors, S1P1, S1P2 and S1P3, which all influence the expression of Ras-related C3 botulinum toxin substrate 1 (Rac1). We designed this study to test the hypothesis that the S1P/Rac1 pathway is altered in the nitrofen-induced CDH model. Pregnant rats received nitrofen or vehicle on D9. On D21, fetuses were killed and divided into nitrofen and control group (n = 12). QRT-PCR, western blotting and confocal-immunofluorescence microscopy were performed to reveal pulmonary gene and protein expression levels of SphK1, S1P1, S1P2, S1P3 and Rac1. Pulmonary gene expression of S1P1 and Rac1 was significantly increased in the CDH group compared to controls, whereas S1P2 and S1P3 expression was decreased. These results were confirmed by western blotting and confocal microscopy. SphK1 expression was not found to be altered. The increased expression of S1P1 and Rac1 in the pulmonary vasculature of nitrofen-induced CDH lungs suggests that S1P1 and Rac1 are important mediators of PH in this model.
Rac1 mediates laminar shear stress-induced vascular endothelial cell migration

PubMed Central

Huang, Xianliang; Shen, Yang; Zhang, Yi; Wei, Lin; Lai, Yi; Wu, Jiang; Liu, Xiaojing; Liu, Xiaoheng

2013-01-01

The migration of endothelial cells (ECs) plays an important role in vascular remodeling and regeneration. ECs are constantly subjected to shear stress resulting from blood flow and are able to convert mechanical stimuli into intracellular signals that affect cellular behaviors and functions. The aim of this study is to elucidate the effects of Rac1, which is the member of small G protein family, on EC migration under different laminar shear stress (5.56, 10.02, and 15.27 dyn/cm2). The cell migration distance under laminar shear stress increased significantly than that under the static culture condition. Especially, under relative high shear stress (15.27 dyn/cm2) there was a higher difference at 8 h (P < 0.01) and 2 h (P < 0.05) compared with static controls. RT-PCR results further showed increasing mRNA expression of Rac1 in ECs exposed to laminar shear stress than that exposed to static culture. Using plasmids encoding the wild-type (WT), an activated mutant (Q61L), and a dominant-negative mutant (T17N), plasmids encoding Rac1 were transfected into EA.hy 926 cells. The average net migration distance of Rac1Q61L group increased significantly, while Rac1T17N group decreased significantly in comparison with the static controls. These results indicated that Rac1 mediated shear stress-induced EC migration. Our findings conduce to elucidate the molecular mechanisms of EC migration induced by shear stress, which is expected to understand the pathophysiological basis of wound healing in health and diseases. PMID:24430179
The application of reduced absorption cross section on the identification of the compounds with similar function-groups

NASA Astrophysics Data System (ADS)

Yu, Fei; Zuo, Jian; Mu, Kai-jun; Zhang, Zhen-wei; Zhang, Liang-liang; Zhang, Lei-wei; Zhang, Cun-lin

2013-08-01

Terahertz spectroscopy is a powerful tool for materials investigation. The low frequency vibrations were usually investigated by means of absorption coefficient regardless of the refractive index. It leads to the disregard of some inherent low-frequency vibrational information of the chemical compounds. Moreover, due to the scattering inside the sample, there are some distortions of the absorption features, so that the absorption dependent material identification is not valid enough. Here, a statistical parameter named reduced absorption cross section (RACS) is introduced. This can not only help us investigate the molecular dynamics but also distinguish one chemical compound with another which has similar function-groups. Experiments are carried out on L-Tyrosine and L-Phenylalanine and the different mass ratios of their mixtures as an example of the application of RACS. The results come out that the RACS spectrum of L-Tyrosine and L-Phenylalanine reserve the spectral fingerprint information of absorption spectrum. The log plot of RACSs of the two amino acids show power-law behavior σR(~ν) ~ (ν~α), and there is a linear relation between the wavenumber and the RACS in the double logarithmic plot. The exponents α, at the same time, are the slopes of the RACS curves in the double logarithmic plot. The big differences of the exponents α between the two amino acids and their mixtures can be seen visually from the slopes of the RACS curves. So we can use RACS analytical method to distinguish some complex compounds with similar function-groups and mixtures from another which has similar absorption peaks in THz region.
The Phospholipase Cγ2 Mutants R665W and L845F Identified in Ibrutinib-resistant Chronic Lymphocytic Leukemia Patients Are Hypersensitive to the Rho GTPase Rac2 Protein.

PubMed

Walliser, Claudia; Hermkes, Elisabeth; Schade, Anja; Wiese, Sebastian; Deinzer, Julia; Zapatka, Marc; Désiré, Laurent; Mertens, Daniel; Stilgenbauer, Stephan; Gierschik, Peter

2016-10-14

Mutations in the gene encoding phospholipase C-γ 2 (PLCγ 2 ) have been shown to be associated with resistance to targeted therapy of chronic lymphocytic leukemia (CLL) with the Bruton's tyrosine kinase inhibitor ibrutinib. The fact that two of these mutations, R665W and L845F, imparted upon PLCγ 2 an ∼2-3-fold ibrutinib-insensitive increase in the concentration of cytosolic Ca 2+ following ligation of the B cell antigen receptor (BCR) led to the assumption that the two mutants exhibit constitutively enhanced intrinsic activity. Here, we show that the two PLCγ 2 mutants are strikingly hypersensitive to activation by Rac2 such that even wild-type Rac2 suffices to activate the mutant enzymes upon its introduction into intact cells. Enhanced "basal" activity of PLCγ 2 in intact cells is shown using the pharmacologic Rac inhibitor EHT 1864 and the PLCγ 2 F897Q mutation mediating Rac resistance to be caused by Rac-stimulated rather than by constitutively enhanced PLCγ 2 activity. We suggest that R665W and L845F be referred to as allomorphic rather than hypermorphic mutations of PLCG2 Rerouting of the transmembrane signals emanating from BCR and converging on PLCγ 2 through Rac in ibrutinib-resistant CLL cells may provide novel drug treatment strategies to overcome ibrutinib resistance mediated by PLCG2 mutations or to prevent its development in ibrutinib-treated CLL patients. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
A Report to the U.S. Department of Education on Educational Challenges and Technical Assistance Needs for the Northeast Region

ERIC Educational Resources Information Center

CNA Corporation, 2005

2005-01-01

The Northeast Regional Advisory Committee (NE RAC) provides an assessment of the technical assistance needs of educators in the Northeast Region in response to a directive from the Secretary of the U.S. Department of Education (ED). The Secretary will use this assessment in establishing 20 comprehensive centers to provide technical assistance to…
Wounding response in xylem of Scots pine seedlings shows wide genetic variation and connection with the constitutive defence of heartwood.

PubMed

Harju, Anni M; Venäläinen, Martti; Laakso, Tapio; Saranpää, Pekka

2009-01-01

In this greenhouse experiment, 3-year-old Scots pine (Pinus sylvestris L.) seedlings were wounded by drilling holes through the stem. In the xylem next to the wound, the concentration of resin acids (RAC) increased, and the production of extractives typical for heartwood (stilbenes) and knotwood (stilbenes and lignans) of mature trees was induced. The induced stilbenes were pinosylvin (PS) and pinosylvin monomethyl ether (PSM), and the lignans nortrachelogenin (NTG) and matairesinol (MR). There was positive phenotypic correlation between concentrations of the different extractives. Except for the RAC, the extractive concentrations showed no correlation with the size of the seedlings. The treated seedlings belonged to half-sib families, which enabled the estimation of the genetic parameters for the response variables. The proportion of heritable variation (heritability, h(2)) in the concentration of PS, NTG and MR varied between 0.71 and 1.03, whereas for PSM and RAC the heritability was lower (0.35 and 0.31). Genetic correlation was significant between PS and PSM (r = 0.55, P = 0.018), and between NTG and MR (r = 0.50, P = 0.033). Heritabilities were also estimated on the basis of the regression of the offspring on their mothers h(2)(0P). These estimates were assessed for the concentration of PS, PSM and RAC in the wound response area of the seedlings and correspondingly in the heartwood of their mothers. The heritability was highest for the concentration of PS h(2)(0P). The findings of this study support the suggestion that the wounding of Scots pine seedlings may facilitate the development of an early testing method for breeding heartwood durability.

Surgical capacity building in Timor-Leste: a review of the first 15 years of the Royal Australasian College of Surgeons-led Australian Aid programme.

PubMed

Guest, Glenn D; Scott, David F; Xavier, Joao P; Martins, Nelson; Vreede, Eric; Chennal, Antony; Moss, Daliah; Watters, David A

2017-06-01

Timor-Leste suffered a destructive withdrawal by the Indonesian military in 1999, leaving only 20 Timorese-based doctors and no practising specialists for a population of 700 000 that has now grown to 1.2 million. This article assesses the outcomes and impact of Royal Australasian College of Surgeons (RACS) specialist medical support from 2001 to 2015. Three programmes were designed collaboratively with the Timor-Leste Ministry of Health and Australian Aid. The RACS team began to provide 24/7 resident surgical and anaesthesia services in the capital, Dili, from July 2001. The arrival of the Chinese and Cuban Medical Teams provided a medical workforce, and the Cubans initiated undergraduate medical training for about 1000 nationals both in Cuba and in Timor-Leste, whilst RACS focused on specialist medical training. Australian Aid provided AUD$20 million through three continuous programmes over 15 years. In the first 10 years over 10 000 operations were performed. Initially only 10% of operations were done by trainees but this reached 77% by 2010. Twenty-one nurse anaesthetists were trained in-country, sufficient to cover the needs of each hospital. Seven Timorese doctors gained specialist qualifications (five surgery, one ophthalmology and one anaesthesia) from regional medical schools in Papua New Guinea, Fiji, Indonesia and Malaysia. They introduced local specialist and family medicine diploma programmes for the Cuban graduates. Timor-Leste has developed increasing levels of surgical and anaesthetic self-sufficiency through multi-level collaboration between the Ministry of Health, Universidade Nacional de Timor Lorosa'e, and sustained, consistent support from external donors including Australian Aid, Cuba and RACS. © 2016 Royal Australasian College of Surgeons.
Medicare recovery audit contractors: what providers need to know and how to prepare.

PubMed

Riley, James B; Greis, Jason S

2009-04-01

RAC audits are on their way in 2009 and all providers should strive to be prepared. In a depressed economy in which most providers are experiencing decreased or stagnating reimbursement, an additional hit to the bottom line from a RAC audit is especially unwelcome. Providers have a number of tools at their disposal, however, to proactively prepare in advance of receiving a RAC demand letter or medical record request.
RADON AND PROGENY SOURCED DOSE ASSESSMENT OF SPA EMPLOYEES IN BALNEOLOGICAL SITES.

PubMed

Uzun, Sefa Kemal; Demiröz, Işık

2016-09-01

This study was conducted in the scope of IAEA project with the name 'Establishing a Systematic Radioactivity Survey and Total Effective Dose Assessment in Natural Balneological Sites' (TUR/9/018), at the Health Physics department of Sarayköy Nuclear Research and Training Center (SANAEM). The aim of this study is estimation of radon and progeny sourced effective dose for the people who are working at the spa facilities by measuring radon activity concentration (RAC) at the ambient air of indoor spa pools and dressing rooms. As it is known, the source of the radon gas is the radium content of the earth crust. Therefore, thermal waters coming from ground may contain dissolved radon and the radon can diffuse water to air. So the ambient air of spa pools can contain serious RAC that depends on a lot of parameters. In this regard, RAC measurements were executed at the 70 spa facilities in Turkey. The measurements were done with both active and passive methods at ambient air of spa pools and dressing rooms. Thus, active measurements were carried out by using the Alphaguard(®) with diffusion mode during half an hour, and passive measurements were carried out by using the humidity resistive CR-39 radon detectors during 2 months. Results show that RAC values at ambient air of spa pools varies between 13 Bq m(-3) and 10 kBq m(-3) Because long-term measurements are more reliable, if it is available, for dose calculations passive radon measurements (with CR-39 detectors) at ambient air of spa pools and dressing rooms were used, otherwise active measurement results were used. With the measurement by the conversion coefficients of ICRP 65 and occupational data of the employees has got from questionary forms, effective dose values were calculated. According to the calculations, spa employees are exposed to annual average dose between 0.05 and 29 mSv because of radon and progeny. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
77 FR 20396 - Request for Nominations of Candidates to the EPA's Clean Air Scientific Advisory Committee (CASAC...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-04

... sciences; risk assessment; and statistics. For further information about the RAC membership appointment... decision sciences; and modeling and statistics. The SAB Staff Office is especially interested in scientists... ENVIRONMENTAL PROTECTION AGENCY [FRL-9656-1] Request for Nominations of Candidates to the EPA's...
Effects of ractopamine and arginine dietary supplementation for sows on growth performance and carcass quality of their progenies.

PubMed

Garbossa, C A P; Carvalho Júnior, F M; Silveira, H; Faria, P B; Schinckel, A P; Abreu, M L T; Cantarelli, V S

2015-06-01

The objective of this study was to evaluate the effects of ractopamine (Rac) and Arg fed to pregnant sows from d 25 to 53 of gestation on fetal muscle development as well as the performance and carcass characteristics of the progeny. One hundred sows were divided into 4 treatments including a control diet, the control plus 1% Arg, the control plus 20 mg/kg Rac, and the control diet supplemented with both additives at the same levels as those used separately. During the farrowing process the data evaluated were the weight of placenta to calculate the placental efficiency and the number of piglets born alive, stillborn, and mummified. To evaluate the fiber number and area, 12 male piglets from each treatment were euthanized to harvest semitendinosus muscle. During the lactation, the preweaning mortality, weaned weights, and number of piglets weaned per litter were evaluated. After weaning, the pig performance was evaluated until the slaughter following the sow treatment. At end of finishing phase, 1 male pig of each treatment replicate was selected to evaluation the carcass and pork quality. All variables measured were analyzed using the MIXED procedure of SAS and least squares means were compared using the Tukey test with P < 0.05. The control diet + supplementation of 1.0% of L-Arg + 20 mg/kg of ractopamine HCl from d 25 to 53 of gestation (Arg+Rac) treatment had a greater number of stillborn piglets (P = 0.014) than the control group. Piglet birth weights from sows fed Rac were 11% greater (P = 0.031) than those of piglets of the control treatment. The semitendinosus muscle fiber diameters of piglets at birth from sows that received Arg, Rac, and Arg+Rac were greater (P < 0.0001) than those of control piglets, and as consequence, the fiber number per square millimeter decreased (P < 0.0001). The final nursery BW of progeny from sows fed Arg and Rac individually were greater (P = 0.010) than those of progeny of the control group. At 110 d of age, in the beginning of the finisher 1 phase, pigs from Arg-fed sows were 1.9 kg heavier (P = 0.010) than pigs from the Arg+Rac-fed sows. The HCW were 2.97 and 1.64 kg heavier (P < 0.0001) for progeny of the Arg and Rac sows, respectively, compared with those of progeny of the control. In conclusion, the trial showed that the use of Rac for gestating sows increased the piglets' weight at birth. The size of muscular fiber was increased in the semitendinosus muscle of piglets originating from sows receiving Rac or Arg. However, the combination of both compounds did not have an additive effect in comparison with the control treatment but increased the stillbirth number.
Structural and magnetic diversity in cyano-bridged bi- and trimetallic complexes assembled from cyanometalates and [M(rac-CTH)]n+ building blocks (CTH = d,l-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane).

PubMed

Rodríguez-Diéguez, Antonio; Kivekäs, Raikko; Sillanpää, Reijo; Cano, Joan; Lloret, Francesc; McKee, Vickie; Stoeckli-Evans, Helen; Colacio, Enrique

2006-12-25

Seven new cyano-bridged heterometallic systems have been prepared by assembling [M'(rac-CTH)]n+ complexes (M' = CrIII, NiII, CuII), which have two cis available coordination positions, and [M(CN)6]3- (M = FeIII, CrIII) and [Fe(CN)2(bpy)2]+ cyanometalate building blocks. The assembled systems, which have been characterized by X-ray crystallography and magnetic investigations, are the molecular squares (meso-CTH-H2)[{Ni(rac-CTH)}2{Fe(CN)6)}2].5H2O (2) and [{Ni(rac-CTH)}2{Fe(CN)2(bpy)2}2](ClO4)4.H2O (5), the bimetallic chain [{Ni(rac-CTH)}2{Cr(CN)6)}2Ni(meso-CTH)].4H2O (3), the trimetallic chain [{Ni(rac-CTH)}2{Fe(CN)6)}2Cu(cyclam)]6H2O (4), the pentanuclear complexes [{Cu(rac-CTH}3{Fe(CN)6}2].2H2O (6) and [{Cu(rac-CTH)}3{Cr(CN)6)}2].2H2O (7), and the dinuclear complex [Cr(rac-CTH)(H2O)Fe(CN)6].2H2O (8). With the exception of 5, all compounds exhibit ferromagnetic interaction between the metal ions (JFeNi = 12.8(2) cm-1 for 2; J1FeCu= 13.8(2) cm-1 and J2FeCu= 3.9(4) cm-1 for 6; J1CrCu= 6.95(3) cm-1 and J2CrCu= 1.9(2)cm-1 for 7; JCrFe = 28.87(3) cm-1 for 8). Compound 5 exhibits the end of a transition from the high-spin to the low-spin state of the octahedral FeII ions. The bimetallic chain 3 behaves as a metamagnet with a critical field Hc = 300 G, which is associated with the occurrence of week antiferromagnetic interactions between the chains. Although the trimetallic chain 4 shows some degree of spin correlation along the chain, magnetic ordering does not occur. The sign and magnitude of the magnetic exchange interaction between CrIII and FeIII in compound 8 have been justified by DFT type calculations.
Enantioselective toxic effects of cyproconazole enantiomers against Chlorella pyrenoidosa.

PubMed

Zhang, Wenjun; Cheng, Cheng; Chen, Li; Di, Shanshan; Liu, Chunxiao; Diao, Jinling; Zhou, Zhiqiang

2016-09-01

Enantioselectivity in ecotoxicity, digestion and uptake of chiral pesticide cyproconazole to Chlorella pyrenoidosa was studied. The 96h-EC50 values of rac- and the four enantiomers were 9.005, 6.616, 8.311, 4.290 and 9.410 mg/L, respectively. At the concentrations of 8 mg/L and 14 mg/L, the contents of pigments exposed in rac-, enantiomer-2 and 4 were higher than that exposed in enantiomer-1 and 3. The superoxide dismutase (SOD) and catalase (CAT) activity of algae exposed to enantiomer-1 and 3 was higher than that exposed to the rac-, enantiomer-2 and 4 at three levels. In addition, the malondialdehyde (MDA) concentrations in algae disposed with enantiomer-1 and 3 were increased remarkably at three levels. For the digestion experiment, the half-lives of four enantiomers in algae suspension were 28.06, 19.10, 21.13, 15.17 days, respectively. During the uptake experiment, the order of the concentrations of cyproconazole in algae cells was enantiomer-4, 2, 3 and 1. Based on these data, we concluded that ecotoxicity, digestion and uptake of chiral pesticide cyproconazole to C. pyrenoidosa were enantioselective, and such enantiomeric differences must be taken into consideration when assessing the risk of cyproconazole to environment. Copyright © 2016 Elsevier Ltd. All rights reserved.
Factors influencing nursing time spent on administration of medication in an Australian residential aged care home.

PubMed

Qian, Siyu; Yu, Ping; Hailey, David M; Wang, Ning

2016-04-01

To examine nursing time spent on administration of medications in a residential aged care (RAC) home, and to determine factors that influence the time to medicate a resident. Information on nursing time spent on medication administration is useful for planning and implementation of nursing resources. Nurses were observed over 12 morning medication rounds using a time-motion observational method and field notes, at two high-care units in an Australian RAC home. Nurses spent between 2.5 and 4.5 hours in a medication round. Administration of medication averaged 200 seconds per resident. Four factors had significant impact on medication time: number of types of medication, number of tablets taken by a resident, methods used by a nurse to prepare tablets and methods to provide tablets. Administration of medication consumed a substantial, though variable amount of time in the RAC home. Nursing managers need to consider the factors that influenced the nursing time required for the administration of medication in their estimation of nursing workload and required resources. To ensure safe medication administration for older people, managers should regularly assess the changes in the factors influencing nursing time on the administration of medication when estimating nursing workload and required resources. © 2015 John Wiley & Sons Ltd.
Distinct molecular underpinnings of Drosophila olfactory trace conditioning

PubMed Central

Shuai, Yichun; Hu, Ying; Qin, Hongtao; Campbell, Robert A. A.; Zhong, Yi

2011-01-01

Trace conditioning is valued as a simple experimental model to assess how the brain associates events that are discrete in time. Here, we adapted an olfactory trace conditioning procedure in Drosophila melanogaster by training fruit flies to avoid an odor that is followed by foot shock many seconds later. The molecular underpinnings of the learning are distinct from the well-characterized simultaneous conditioning, where odor and punishment temporally overlap. First, Rutabaga adenylyl cyclase (Rut-AC), a putative molecular coincidence detector vital for simultaneous conditioning, is dispensable in trace conditioning. Second, dominant-negative Rac expression, thought to sustain early labile memory, significantly enhances learning of trace conditioning, but leaves simultaneous conditioning unaffected. We further show that targeting Rac inhibition to the mushroom body (MB) but not the antennal lobe (AL) suffices to achieve the enhancement effect. Moreover, the absence of trace conditioning learning in D1 dopamine receptor mutants is rescued by restoration of expression specifically in the adult MB. These results suggest the MB as a crucial neuroanatomical locus for trace conditioning, which may harbor a Rac activity-sensitive olfactory “sensory buffer” that later converges with the punishment signal carried by dopamine signaling. The distinct molecular signature of trace conditioning revealed here shall contribute to the understanding of how the brain overcomes a temporal gap in potentially related events. PMID:22123966
Differential regulation of the Rac1 GTPase-activating protein (GAP) BCR during oxygen/glucose deprivation in hippocampal and cortical neurons.

PubMed

Smith, Katharine R; Rajgor, Dipen; Hanley, Jonathan G

2017-12-08

Brain ischemia causes oxygen and glucose deprivation (OGD) in neurons, triggering a cascade of events leading to synaptic accumulation of glutamate. Excessive activation of glutamate receptors causes excitotoxicity and delayed cell death in vulnerable neurons. Following global cerebral ischemia, hippocampal CA1 pyramidal neurons are more vulnerable to injury than their cortical counterparts, but the mechanisms that underlie this difference are unclear. Signaling via Rho-family small GTPases, their upstream guanine nucleotide exchange factors, and GTPase-activating proteins (GAPs) is differentially dysregulated in response to OGD/ischemia in hippocampal and cortical neurons. Increased Rac1 activity caused by OGD/ischemia contributes to neuronal death in hippocampal neurons via diverse effects on NADPH oxidase activity and dendritic spine morphology. The Rac1 guanine nucleotide exchange factor Tiam1 mediates an OGD-induced increase in Rac1 activity in hippocampal neurons; however, the identity of an antagonistic GAP remains elusive. Here we show that the Rac1 GAP breakpoint cluster region (BCR) associates with NMDA receptors (NMDARs) along with Tiam1 and that this protein complex is more abundant in hippocampal compared with cortical neurons. Although total BCR is similar in the two neuronal types, BCR is more active in hippocampal compared with cortical neurons. OGD causes an NMDAR- and Ca 2+ -permeable AMPAR-dependent deactivation of BCR in hippocampal but not cortical neurons. BCR knockdown occludes OGD-induced Rac1 activation in hippocampal neurons. Furthermore, disrupting the Tiam1-NMDAR interaction with a fragment of Tiam1 blocks OGD-induced Tiam1 activation but has no effect on the deactivation of BCR. This work identifies BCR as a critical player in Rac1 regulation during OGD in hippocampal neurons. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Enantioconvergent hydrolysis of racemic styrene oxide at high concentration by a pair of novel epoxide hydrolases into (R)-phenyl-1,2-ethanediol.

PubMed

Wang, Rui; Hu, Die; Zong, Xuncheng; Li, Jinping; Ding, Lei; Wu, Minchen; Li, Jianfang

2017-12-01

To prepare (R)-phenyl-1,2-ethanediol ((R)-PED) with high enantiomeric excess (ee p ) and yield from racemic styrene oxide (rac-SO) at high concentration by bi-enzymatic catalysis. The bi-enzymatic catalysis was designed for enantioconvergent hydrolysis of rac-SO by a pair of novel epoxide hydrolases (EHs), a Vigna radiata EH3 (VrEH3) and a variant (AuEH2 A250I ) of Aspergillus usamii EH2. The simultaneous addition mode of VrEH3 and AuEH2 A250I , exhibiting the highest average turnover frequency (aTOF) of 0.12 g h -1 g -1 , was selected, by which rac-SO (10 mM) was converted into (R)-PED with 92.6% ee p and 96.3% yield. Under the optimized reaction conditions: dry weight ratio 14:1 of VrEH3-expressing E. coli/vreh3 to AuEH2 A250I -expressing E. coli/Aueh2 A250I and reaction at 20 °C, rac-SO (10 mM) was completely hydrolyzed in 2.3 h, affording (R)-PED with 98% ee p . At the weight ratio 0.8:1 of rac-SO to two mixed dry cells, (R)-PED with 97.4% ee p and 98.7% yield was produced from 200 mM (24 mg/ml) rac-SO in 10.5 h. Enantioconvergent hydrolysis of rac-SO at high concentration catalyzed by both VrEH3 and AuEH2 A250I is an effective method for preparing (R)-PED with high ee p and yield.
Abnormal striatal dopaminergic neurotransmission during rest and task production in spasmodic dysphonia.

PubMed

Simonyan, Kristina; Berman, Brian D; Herscovitch, Peter; Hallett, Mark

2013-09-11

Spasmodic dysphonia is a primary focal dystonia characterized by involuntary spasms in the laryngeal muscles during speech production. The pathophysiology of spasmodic dysphonia is thought to involve structural and functional abnormalities in the basal ganglia-thalamo-cortical circuitry; however, neurochemical correlates underpinning these abnormalities as well as their relations to spasmodic dysphonia symptoms remain unknown. We used positron emission tomography with the radioligand [(11)C]raclopride (RAC) to study striatal dopaminergic neurotransmission at the resting state and during production of symptomatic sentences and asymptomatic finger tapping in spasmodic dysphonia patients. We found that patients, compared to healthy controls, had bilaterally decreased RAC binding potential (BP) to striatal dopamine D2/D3 receptors on average by 29.2%, which was associated with decreased RAC displacement (RAC ΔBP) in the left striatum during symptomatic speaking (group average difference 10.2%), but increased RAC ΔBP in the bilateral striatum during asymptomatic tapping (group average difference 10.1%). Patients with more severe voice symptoms and subclinically longer reaction time to initiate the tapping sequence had greater RAC ΔBP measures, while longer duration of spasmodic dysphonia was associated with a decrease in task-induced RAC ΔBP. Decreased dopaminergic transmission during symptomatic speech production may represent a disorder-specific pathophysiological trait involved in symptom generation, whereas increased dopaminergic function during unaffected task performance may be explained by a compensatory adaptation of the nigrostriatal dopaminergic system possibly due to decreased striatal D2/D3 receptor availability. These changes can be linked to the clinical and subclinical features of spasmodic dysphonia and may represent the neurochemical basis of basal ganglia alterations in this disorder.
Abnormal Striatal Dopaminergic Neurotransmission during Rest and Task Production in Spasmodic Dysphonia

PubMed Central

Berman, Brian D.; Herscovitch, Peter; Hallett, Mark

2013-01-01

Spasmodic dysphonia is a primary focal dystonia characterized by involuntary spasms in the laryngeal muscles during speech production. The pathophysiology of spasmodic dysphonia is thought to involve structural and functional abnormalities in the basal ganglia–thalamo-cortical circuitry; however, neurochemical correlates underpinning these abnormalities as well as their relations to spasmodic dysphonia symptoms remain unknown. We used positron emission tomography with the radioligand [11C]raclopride (RAC) to study striatal dopaminergic neurotransmission at the resting state and during production of symptomatic sentences and asymptomatic finger tapping in spasmodic dysphonia patients. We found that patients, compared to healthy controls, had bilaterally decreased RAC binding potential (BP) to striatal dopamine D2/D3 receptors on average by 29.2%, which was associated with decreased RAC displacement (RAC ΔBP) in the left striatum during symptomatic speaking (group average difference 10.2%), but increased RAC ΔBP in the bilateral striatum during asymptomatic tapping (group average difference 10.1%). Patients with more severe voice symptoms and subclinically longer reaction time to initiate the tapping sequence had greater RAC ΔBP measures, while longer duration of spasmodic dysphonia was associated with a decrease in task-induced RAC ΔBP. Decreased dopaminergic transmission during symptomatic speech production may represent a disorder-specific pathophysiological trait involved in symptom generation, whereas increased dopaminergic function during unaffected task performance may be explained by a compensatory adaptation of the nigrostriatal dopaminergic system possibly due to decreased striatal D2/D3 receptor availability. These changes can be linked to the clinical and subclinical features of spasmodic dysphonia and may represent the neurochemical basis of basal ganglia alterations in this disorder. PMID:24027271
Glucotoxicity promotes aberrant activation and mislocalization of Ras-related C3 botulinum toxin substrate 1 [Rac1] and metabolic dysfunction in pancreatic islet β-cells: reversal of such metabolic defects by metformin.

PubMed

Baidwan, Sartaj; Chekuri, Anil; Hynds, DiAnna L; Kowluru, Anjaneyulu

2017-11-01

Emerging evidence suggests that long-term exposure of insulin-secreting pancreatic β-cells to hyperglycemic (HG; glucotoxic) conditions promotes oxidative stress, which, in turn, leads to stress kinase activation, mitochondrial dysfunction, loss of nuclear structure and integrity and cell apoptosis. Original observations from our laboratory have proposed that Rac1 plays a key regulatory role in the generation of oxidative stress and downstream signaling events culminating in the onset of dysfunction of pancreatic β-cells under the duress of metabolic stress. However, precise molecular and cellular mechanisms underlying the metabolic roles of hyperactive Rac1 remain less understood. Using pharmacological and molecular biological approaches, we now report mistargetting of biologically-active Rac1 [GTP-bound conformation] to the nuclear compartment in clonal INS-1 cells, normal rat islets and human islets under HG conditions. Our findings also suggest that such a signaling step is independent of post-translational prenylation of Rac1. Evidence is also presented to highlight novel roles for sustained activation of Rac1 in HG-induced expression of Cluster of Differentiation 36 [CD36], a fatty acid transporter protein, which is implicated in cell apoptosis. Finally, our findings suggest that metformin, a biguanide anti-diabetic drug, at a clinically relevant concentration, prevents β-cell defects [Rac1 activation, nuclear association, CD36 expression, stress kinase and caspase-3 activation, and loss in metabolic viability] under the duress of glucotoxicity. Potential implications of these findings in the context of novel and direct regulation of islet β-cell function by metformin are discussed.
Recovery Audit Contractor audits and appeals at three academic medical centers.

PubMed

Sheehy, Ann M; Locke, Charles; Engel, Jeannine Z; Weissburg, Daniel J; Mackowiak, Stephanie; Caponi, Bartho; Gangireddy, Sreedevi; Deutschendorf, Amy

2015-04-01

Outpatient (observation) and inpatient status determinations for hospitalized Medicare beneficiaries have generated increasing concern for hospitals and patients. Recovery Audit Contractor (RAC) activity alleging improper status, however, has received little attention, and there are conflicting federal and hospital reports of RAC activity and hospital appeals success. To detail complex Medicare Part A RAC activity. Retrospective descriptive study of complex Medicare Part A audits at 3 academic hospitals from 2010 to 2013. Complex Part A audits, outcome of audits, and hospital workforce required to manage this process. Of 101,862 inpatient Medicare encounters, RACs audited 8110 (8.0%) encounters, alleged overpayment in 31.3% (2536/8110), and hospitals disputed 91.0% (2309/2536). There was a nearly 3-fold increase in RAC overpayment determinations in 2 years, although the hospitals contested and won a larger percent of cases each year. One-third (645/1935, 33.3%) of settled claims were decided in the discussion period, which are favorable decisions for the hospitals not reported in federal appeals data. Almost half (951/1935, 49.1%) of settled contested cases were withdrawn by the hospitals and rebilled under Medicare Part B to avoid the lengthy (mean 555 [SD 255] days) appeals process. These original inpatient claims are considered improper payments recovered by the RAC. The hospitals also lost appeals (0.9%) by missing a filing deadline, yet there was no reciprocal case concession when the appeals process missed a deadline. No overpayment determinations contested the need for care delivered, rather that care should have been delivered under outpatient, not inpatient, status. The institutions employed an average 5.1 full-time staff in the audits process. These findings suggest a need for RAC reform, including improved transparency in data reporting. © 2015 Society of Hospital Medicine.
Different design of enzyme-triggered CO-releasing molecules (ET-CORMs) reveals quantitative differences in biological activities in terms of toxicity and inflammation.

PubMed

Stamellou, E; Storz, D; Botov, S; Ntasis, E; Wedel, J; Sollazzo, S; Krämer, B K; van Son, W; Seelen, M; Schmalz, H G; Schmidt, A; Hafner, M; Yard, B A

2014-01-01

Acyloxydiene-Fe(CO)3 complexes can act as enzyme-triggered CO-releasing molecules (ET-CORMs). Their biological activity strongly depends on the mother compound from which they are derived, i.e. cyclohexenone or cyclohexanedione, and on the position of the ester functionality they harbour. The present study addresses if the latter characteristic affects CO release, if cytotoxicity of ET-CORMs is mediated through iron release or inhibition of cell respiration and to what extent cyclohexenone and cyclohexanedione derived ET-CORMs differ in their ability to counteract TNF-α mediated inflammation. Irrespective of the formulation (DMSO or cyclodextrin), toxicity in HUVEC was significantly higher for ET-CORMs bearing the ester functionality at the outer (rac-4), as compared to the inner (rac-1) position of the cyclohexenone moiety. This was paralleled by an increased CO release from the former ET-CORM. Toxicity was not mediated via iron as EC50 values for rac-4 were significantly lower than for FeCl2 or FeCl3 and were not influenced by iron chelation. ATP depletion preceded toxicity suggesting impaired cell respiration as putative cause for cell death. In long-term HUVEC cultures inhibition of VCAM-1 expression by rac-1 waned in time, while for the cyclohexanedione derived rac-8 inhibition seems to increase. NFκB was inhibited by both rac-1 and rac-8 independent of IκBα degradation. Both ET-CORMs activated Nrf-2 and consequently induced the expression of HO-1. This study further provides a rational framework for designing acyloxydiene-Fe(CO)3 complexes as ET-CORMs with differential CO release and biological activities. We also provide a better understanding of how these complexes affect cell-biology in mechanistic terms.
Role of Protein Kinase C Epsilon in Prostate Cancer and Metastasis

DTIC Science & Technology

2013-08-01

detected by Western blot using an anti-Rac1 antibody. Depletion of PKCε with either #4 or #8 RNAi duplexed reduced Rac1 activation levels under serum ... serum deprivation condition was not abolished when PKCε was knocked down and therefore Rac1 activity was reduced. Although these results may implicate...medium supplemented with 10% serum . After different times the number of cells attached was quantified by MTT assay. (e) RWPE-1 cells were infected
Continuous Reusability using Immobilized HasApf in Chemoenzymatic Deracemization: A New Heterogeneous Enzyme Catalysis.

PubMed

Nagaoka, Hiroyuki

2016-10-25

This study found that the calibration curve of heme acquisition system A (HasA, a new reactive active species) immobilized by a porous ceramic particle (ImHApf; immobilized HasA from Pseudomonas fluorescens ) can be constructed in the range of 1750-1450 cm -1 using Fourier transform infrared spectroscopy (FTIR) analysis, and evaluated its catalytic efficiency. In the asymmetric oxidation of rac -1-(6-methoxynaphthalen-2-yl)ethanol ( rac - 1 : a naproxen precursor), a product ketone from the ( R )-isomer is desymmetrized using NaBH₄ and continuously reused even if treated with an organic solvent in 50 mM glycine-NaOH buffer at 40 °C in the absence of nicotinamide adenine dinucleotide (NAD(P)), leading to >99% enantiomeric excess and >90% chemical yield; the activity was calculated at 0.74 ± 0.03 mU/(mg·min) and the turnover number was determined to be approximately 2 × 10⁶. It was confirmed that the other sec -alcohols such as rac -1-(2-naphthyl)ethanol ( rac - 2 ) and m - and p -substituted rac -1-phenyl ethanols ( rac - 3ab - 6ab ) using ImHApf can also yield a single stereoisomer from a racemate. Therefore, HasA immobilization can be expected to become an important tool for building an environmentally friendly system that promotes industrial sustainability.
Two closely related Rho GTPases, Cdc42 and RacA, of the en-dophytic fungus Epichloë festucae have contrasting roles for ROS production and symbiotic infection synchronized with the host plant

PubMed Central

2018-01-01

Epichloë festucae is an endophytic fungus which systemically colonizes temperate grasses to establish symbiotic associations. Maintaining symptomless infection is a key requirement for endophytes, a feature that distinguishes them from pathogenic fungi. While pathogenic fungi extend their hyphae by tip growth, hyphae of E. festucae systemically colonize the intercellular space of expanding host leaves via a unique mechanism of hyphal intercalary growth. This study reports that two homologous Rho GTPases, Cdc42 and RacA, have distinctive roles in the regulation of E. festucae growth in planta. Here we highlight the vital role of Cdc42 for intercalary hyphal growth, as well as involvement of RacA in regulation of hyphal network formation, and demonstrate the consequences of mutations in these genes on plant tissue infection. Functions of Cdc42 and RacA are mediated via interactions with BemA and NoxR respectively, which are expected components of the ROS producing NOX complex. Symbiotic defects found in the racA mutant were rescued by introduction of a Cdc42 with key amino acids substitutions crucial for RacA function, highlighting the significance of the specific interactions of these GTPases with BemA and NoxR for their functional differentiation in symbiotic infection. PMID:29370294
Two closely related Rho GTPases, Cdc42 and RacA, of the en-dophytic fungus Epichloë festucae have contrasting roles for ROS production and symbiotic infection synchronized with the host plant.

PubMed

Kayano, Yuka; Tanaka, Aiko; Takemoto, Daigo

2018-01-01

Epichloë festucae is an endophytic fungus which systemically colonizes temperate grasses to establish symbiotic associations. Maintaining symptomless infection is a key requirement for endophytes, a feature that distinguishes them from pathogenic fungi. While pathogenic fungi extend their hyphae by tip growth, hyphae of E. festucae systemically colonize the intercellular space of expanding host leaves via a unique mechanism of hyphal intercalary growth. This study reports that two homologous Rho GTPases, Cdc42 and RacA, have distinctive roles in the regulation of E. festucae growth in planta. Here we highlight the vital role of Cdc42 for intercalary hyphal growth, as well as involvement of RacA in regulation of hyphal network formation, and demonstrate the consequences of mutations in these genes on plant tissue infection. Functions of Cdc42 and RacA are mediated via interactions with BemA and NoxR respectively, which are expected components of the ROS producing NOX complex. Symbiotic defects found in the racA mutant were rescued by introduction of a Cdc42 with key amino acids substitutions crucial for RacA function, highlighting the significance of the specific interactions of these GTPases with BemA and NoxR for their functional differentiation in symbiotic infection.

Roles of STEF/Tiam1, guanine nucleotide exchange factors for Rac1, in regulation of growth cone morphology.

PubMed

Matsuo, Naoki; Terao, Mami; Nabeshima, Yo-ichi; Hoshino, Mikio

2003-09-01

Rho family GTPases are suggested to be pivotal for growth cone behavior, but regulation of their activities in response to environmental cues remains elusive. Here, we describe roles of STEF and Tiam1, guanine nucleotide exchange factors for Rac1, in neurite growth and growth cone remodeling. We reveal that, in primary hippocampal neurons, STEF/Tiam1 are localized within growth cones and essential for formation of growth cone lamellipodia, eventually contributing to neurite growth. Furthermore, experiments using a dominant-negative form demonstrate that STEF/Tiam1 mediate extracellular laminin signals to activate Rac1, promoting neurite growth in N1E-115 neuroblastoma cells. STEF/Tiam1 are revealed to mediate Cdc42 signal to activate Rac1 during lamellipodial formation. We also show that RhoA inhibits the STEF/Tiam1-Rac1 pathway. These data are used to propose a model that extracellular and intracellular information is integrated by STEF/Tiam1 to modulate the balance of Rho GTPase activities in the growth cone and, consequently, to control growth cone behavior.
Narcolepsy Treated with Racemic Amphetamine during Pregnancy and Breastfeeding.

PubMed

Öhman, Inger; Wikner, Birgitta Norstedt; Beck, Olof; Sarman, Ihsan

2015-08-01

This case report describes a woman with narcolepsy treated with racemic amphetamine (rac-amphetamine) during pregnancy and breastfeeding with follow-up on the infant's development up to 10 months of age. The pregnancy outcome and the pharmacokinetics of rac-amphetamine were studied during breastfeeding. The pregnancy and the delivery were uneventful. Concentrations of rac-amphetamine were determined in the plasma of the mother and infant, and in the breast milk with a liquid chromatography-mass spectrometry method. Samples were obtained at 2, 5, and 9 weeks postpartum. The transfer of rac-amphetamine to the breast milk was extensive (mean milk/maternal plasma concentration ratio approximately 3). The breastfed infant had a low plasma concentration of rac-amphetamine (about 9% of the maternal plasma level) and the calculated relative infant dose was low (2%). No adverse effects were observed in the breastfed infant. The infant's somatic and psychomotor development up to 10 months of age was normal. Further studies of amphetamine prescribed for medical reasons during pregnancy and lactation are needed. © The Author(s) 2015.
Rac1/Pak1/p38/MMP-2 axis regulates angiogenesis in ovarian cancer

PubMed Central

Gonzalez-Villasana, Vianey; Fuentes-Mattei, Enrique; Ivan, Cristina; Dalton, Heather J.; Rodriguez-Aguayo, Cristian; Fernandez-de Thomas, Ricardo J.; Aslan, Burcu; Monroig, Paloma del C.; Velazquez-Torres, Guermarie; Previs, Rebecca A.; Pradeep, Sunila; Kahraman, Nermin; Wang, Huamin; Kanlikilicer, Pinar; Ozpolat, Bulent; Calin, George; Sood, Anil K.; Lopez-Berestein, Gabriel

2015-01-01

Purpose Zoledronic acid (ZA) is being increasingly recognized for its anti-tumor properties, but the underlying functions are not well understood. In this study, we hypothesized that ZA inhibits ovarian cancer (OC) angiogenesis preventing Rac1 activation. Experimental Design The biological effects of ZA were examined using a series of in vitro (cell invasion, cytokine production, Rac1 activation, reverse-phase protein array and in vivo (orthotopic mouse models) experiments. Results There was significant inhibition of OC (HeyA8-MDR and OVCAR-5) cell invasion as well as reduced production of pro-angiogenic cytokines in response to ZA treatment. Furthermore, ZA inactivated Rac1 and decreased the levels of Pak1/p-38/matrix metalloproteinase-2 in OC cells. In vivo, ZA reduced tumor growth, angiogenesis and cell proliferation and inactivated Rac1 in both HeyA8-MDR and OVCAR-5 models. These in vivo antitumor effects were enhanced in both models when ZA was combined with nab-paclitaxel. Conclusion ZA has robust anti-tumor and anti-angiogenic activity and merits further clinical development as OC treatment. PMID:25595279
siRNA Screen Identifies Trafficking Host Factors that Modulate Alphavirus Infection

PubMed Central

Radoshitzky, Sheli R.; Pegoraro, Gianluca; Chī, Xiǎolì; Dǒng, Lián; Chiang, Chih-Yuan; Jozwick, Lucas; Clester, Jeremiah C.; Cooper, Christopher L.; Courier, Duane; Langan, David P.; Underwood, Knashka; Kuehl, Kathleen A.; Sun, Mei G.; Caì, Yíngyún; Yú, Shuǐqìng; Burk, Robin; Zamani, Rouzbeh; Kota, Krishna; Kuhn, Jens H.; Bavari, Sina

2016-01-01

Little is known about the repertoire of cellular factors involved in the replication of pathogenic alphaviruses. To uncover molecular regulators of alphavirus infection, and to identify candidate drug targets, we performed a high-content imaging-based siRNA screen. We revealed an actin-remodeling pathway involving Rac1, PIP5K1- α, and Arp3, as essential for infection by pathogenic alphaviruses. Infection causes cellular actin rearrangements into large bundles of actin filaments termed actin foci. Actin foci are generated late in infection concomitantly with alphavirus envelope (E2) expression and are dependent on the activities of Rac1 and Arp3. E2 associates with actin in alphavirus-infected cells and co-localizes with Rac1–PIP5K1-α along actin filaments in the context of actin foci. Finally, Rac1, Arp3, and actin polymerization inhibitors interfere with E2 trafficking from the trans-Golgi network to the cell surface, suggesting a plausible model in which transport of E2 to the cell surface is mediated via Rac1- and Arp3-dependent actin remodeling. PMID:27031835
The Ribosome-Bound Chaperones RAC and Ssb1/2p Are Required for Accurate Translation in Saccharomyces cerevisiae

PubMed Central

Rakwalska, Magdalena; Rospert, Sabine

2004-01-01

The chaperone homologs RAC (ribosome-associated complex) and Ssb1/2p are anchored to ribosomes; Ssb1/2p directly interacts with nascent polypeptides. The absence of RAC or Ssb1/2p results in a similar set of phenotypes, including hypersensitivity against the aminoglycoside paromomycin, which binds to the small ribosomal subunit and compromises the fidelity of translation. In order to understand this phenomenon we measured the frequency of translation termination and misincorporation in vivo and in vitro with a novel reporter system. Translational fidelity was impaired in the absence of functional RAC or Ssb1/2p, and the effect was further enhanced by paromomycin. The mutant strains suffered primarily from a defect in translation termination, while misincorporation was compromised to a lesser extent. Consistently, a low level of soluble translation termination factor Sup35p enhanced growth defects in the mutant strains. Based on the combined data we conclude that RAC and Ssb1/2p are crucial in maintaining translational fidelity beyond their postulated role as chaperones for nascent polypeptides. PMID:15456889
The ribosome-bound chaperones RAC and Ssb1/2p are required for accurate translation in Saccharomyces cerevisiae.

PubMed

Rakwalska, Magdalena; Rospert, Sabine

2004-10-01

The chaperone homologs RAC (ribosome-associated complex) and Ssb1/2p are anchored to ribosomes; Ssb1/2p directly interacts with nascent polypeptides. The absence of RAC or Ssb1/2p results in a similar set of phenotypes, including hypersensitivity against the aminoglycoside paromomycin, which binds to the small ribosomal subunit and compromises the fidelity of translation. In order to understand this phenomenon we measured the frequency of translation termination and misincorporation in vivo and in vitro with a novel reporter system. Translational fidelity was impaired in the absence of functional RAC or Ssb1/2p, and the effect was further enhanced by paromomycin. The mutant strains suffered primarily from a defect in translation termination, while misincorporation was compromised to a lesser extent. Consistently, a low level of soluble translation termination factor Sup35p enhanced growth defects in the mutant strains. Based on the combined data we conclude that RAC and Ssb1/2p are crucial in maintaining translational fidelity beyond their postulated role as chaperones for nascent polypeptides.
75 FR 54846 - Ketchikan Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-09

... electronically to Diane Daniels, RAC Coordinator at [email protected] . FOR FURTHER INFORMATION CONTACT: Diane Daniels, RAC Coordinator Ketchikan--Misty Fiords Ranger District, Tongass National Forest, (907) 228-4105...
76 FR 20310 - Ketchikan Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-12

...., Ketchikan, AK 99901, or electronically to Diane Daniels, RAC Coordinator at [email protected] . FOR FURTHER INFORMATION CONTACT: Diane Daniels, RAC Coordinator Ketchikan-Misty Fiords Ranger District, Tongass National...
The GTPase Rac-1 controls cell fate in the thymus by diverting thymocytes from positive to negative selection.

PubMed

Gomez, M; Kioussis, D; Cantrell, D A

2001-11-01

The positive selection of CD4 or CD8 single-positive mature peripheral T lymphocytes and the deletion of self-reactive cells are crucial for central tolerance in the peripheral immune system. Previously, the guanine nucleotide binding protein Rac-1 has been shown to control pre-T cell development. The present report now describes the actions of Rac-1 in thymocyte selection. The study reveals that this molecule has the striking and unique ability to efficiently divert cells from positive selection into a pathway of negative selection and deletion. The ability of Rac-1 to switch thymocytes from a destiny of positive to negative selection identifies this molecule as a critical regulator of the developmental processes in T cells that are essential for immune homeostasis.
The Relationship between Using Electronic Health Records and Meeting Accreditation Standards for Client Safety in Residential Aged Care Homes.

PubMed

Jiang, Tao; Yu, Ping

2015-01-01

This study aims to identify the benefits of using electronic health records (EHR) for client safety in residential aged care (RAC) homes. The aged care accreditation reports published between 27 April 2011 and 3 December 2013 were downloaded and analysed. It could be seen from these reports that only 1,031(37.45%) RAC homes in Australia had adopted an EHR system by 2013. 13 RAC homes failed one or more accreditation standards. Only one of these was using an EHR system and this one met the accreditation standards on information systems. Our study provides empirical evidence to suggest that adopting and using EHR can be one of the effective organisational mechanisms to meeting accreditation standards in RAC homes.
76 FR 21330 - Lynn Canal/Icy Straits Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-15

..., 8510 Mendenhall Loop Road, Juneau, Alaska 99801, or electronically to Debra Robinson, RAC Coordinator at [email protected] . FOR FURTHER INFORMATION CONTACT: Debra Robinson, RAC Coordinator Juneau...
75 FR 42375 - Missoula County Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-21

... RAC legislation and RAC mission, establish a process for project proposal evaluation and decision making, set future meeting dates and receive public comment on the meeting subjects and proceedings...
USSR Report, Engineering and Equipment

DTIC Science & Technology

1986-08-13

JlHHHpoM H racHTeJiex B JIHHHK Ha- THeTaHH« aa racHTe/iew (ycpeAKeHHCx1 3Ha" ;:’ HHO ) i. \\ TpyOa-racHTcnb 400 MM {puc~ 4) =2,5 MTIa...reliable operation of fly-ash collectors in the period between overhauls of boilers . The walls of the modernized fly-ash collectors, in spite of...capacity of boiler , t/h Reduced ash content of fuel, %/ /(MJ/kg) [Continued on following page] Mixture of Donetsk coal 608-612 1.3-1.45 18
Microcircuit Device Reliability. Digital Evaluation and Failure Analysis Data. Parts 1 and 2, Summer 1980

DTIC Science & Technology

1980-01-01

l1i Research Institute (IITRI). RAC is charged with the collection , analysis and dis- semination of reliabil;,y information pertaining to parts used...RCM) is also operating under the auspices of the RAC and serves as the focal point for the collection and analysis of all reliability-related in...the Rome Air Development Center (RADC), and operated at RADC hy lI Research Institute (IITR I). RAC is charged with the collection , analysis and dis
Impact of Vascular Hemodynamics on Aortic Stenosis Evaluation: New Insights Into the Pathophysiology of Normal Flow-Small Aortic Valve Area-Low Gradient Pattern.

PubMed

Côté, Nancy; Simard, Louis; Zenses, Anne-Sophie; Tastet, Lionel; Shen, Mylène; Clisson, Marine; Clavel, Marie-Annick

2017-07-07

About 50% of normal-flow/low-gradient patients (ie, low mean gradient [MG] or peak aortic jet velocity and small aortic valve area) have severe aortic valve calcification as measured by computed tomography. However, they are considered to have moderate aortic stenosis (AS) in current American College of Cardiology/American Heart Association guidelines. The objective was thus to evaluate the effect of hypertension and reduced arterial compliance (rAC) on MG and V peak measurements. Doppler-echocardiography was performed in 4 sheep with experimentally induced severe and critical AS at: (1) normal aortic pressure, (2) during hypertension, and (3) with rAC. Hypertension and rAC induced a substantial decrease in MG/V peak compared with normal stage (both P ≤0.03) despite a stable transvalvular flow ( P >0.16). Hypertension and rAC resulted in a greater reduction of MG in critical (-42%) compared with severe (-35%) AS ( P ˂0.0001). Comprehensive Doppler-echocardiography and computed tomography were performed in 220 AS patients (mean age: 69±13 years; MG 29±18 mm Hg) with normal flow. The population was divided in 3 groups according to the presence of hypertension and rAC. The slope of the linear association between MG/V peak and aortic valve calcification divided by the cross-sectional area of the aortic annulus was significantly reduced in patients with hypertension and/or rAC compared with normotensive/normal AC patients ( P <0.01). Accordingly, patients with normal-flow/low-gradient and severe aortic valve calcification density were more frequent in hypertension and rAC groups compared with the normotensive/normal-AC group (16% and 12% compared with 2%; P =0.03). Hypertension and rAC are associated with a substantial reduction in MG/V peak for similar aortic valve calcification (ie, similar AS anatomic severity), which may lead to underestimation of AS hemodynamic severity. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.
Fresh meat and further processing characteristics of ham muscles from finishing pigs fed ractopamine hydrochloride.

PubMed

Boler, D D; Holmer, S F; Duncan, D A; Carr, S N; Ritter, M J; Stites, C R; Petry, D B; Hinson, R B; Allee, G L; McKeith, F K; Killefer, J

2011-01-01

Ractopamine hydrochloride (RAC) has consistently led to an advantage in carcass cutting yields of finishing pigs and remains a common feed additive in US finishing pig diets. Less is known about the effect of RAC on further processing characteristics. Some researchers have reported advantages in ultimate pH of the LM in pigs fed RAC. If a greater ultimate pH was also observed in hams, the increased pH could affect further processing characteristics and lead to better protein interaction and improved textural properties. The objective of this experiment was to determine if RAC-fed pigs yielded hams with a greater ultimate pH, and if so, whether or not that advantage improves textural properties and water retention of further processed hams. Two hundred hams from barrows and gilts fed RAC or control diets were selected based on HCW. Hams were fabricated into 5 separate pieces to determine cutting yields, and 6 muscles were evaluated for ultimate pH. Hams were processed to make cured and smoked hams. Ractopamine increased cutting yields of the whole ham (P < 0.0001), inside (P < 0.01), outside (P < 0.01), and knuckle (P < 0.01) when expressed as a percentage of chilled side weight. Ultimate pH of the rectus femoris, vastus lateralis, and semitendinosus were all 0.06 pH units greater (P < 0.05), the biceps femoris was 0.04 pH units greater (P = 0.02), and the semimembranosus and adductor muscles were 0.03 pH units greater in pigs fed 7.4 mg/kg of RAC when compared with control pigs. Cured hams from RAC-fed pigs were heavier at all stages of production. No differences were detected in binding strengths (P = 0.88) or protein fat-free values (P = 0.13) between RAC (9.06 kg and 20.37) and control hams (9.01 kg and 20.13). Ractopamine increased cutting yields, total weight of cured hams, and ultimate muscle pH. Ractopamine can be fed to pigs to achieve the desired growth characteristic advantages and cutting yields without affecting further processed ham characteristics.
Effect of ractopamine-hydrochloride and trenbolone acetate on longissimus muscle fiber area, diameter, and satellite cell numbers in cull beef cows.

PubMed

Gonzalez, J M; Carter, J N; Johnson, D D; Ouellette, S E; Johnson, S E

2007-08-01

The objective of this study was to evaluate the effects of coadministration of ractopamine-HCl (RAC) and trenbolone acetate plus estradiol (TBA) on LM fiber cross-sectional area (CSA), diameter, fiber-associated myonuclei, and satellite cell number. Culled crossbred beef cows (n = 98; 11 +/- 1.8 yr old; BCS 4.3 +/- 0.03) from a single ranch in south Florida were fed a concentrate diet for 92 d in a 2 x 2, randomized block design. Cows were blocked by BW on arrival into light (initial BW = 369.75 +/- 2.68 kg and end BW = 501.96 +/- 6.90 kg) and heavy (initial BW = 418.31 +/- 2.75 kg and end BW = 522.15 +/- 7.09 kg) groups before assignment to treatment. Factors included dietary treatment (0 or 15 ppm) and implant status (0 or 80 mg of trenbolone acetate + 16 mg of estradiol). Ractopamine was provided in the diet to 2 pens or half the treatments during the final 35 d of feeding. Cows were slaughtered on d 92. Forty-eight hours postmortem, the 6th-rib portions of the LM were obtained from 10 randomly selected carcasses from each treatment group (n = 40). Cryosections (12 mum) were immunostained for dystrophin and myosin heavy chain I or II for the measurement of fiber CSA and type, respectively. Fiber-associated nuclei and satellite cell numbers were measured in serial cryosections. There was a RAC x TBA interaction (P < 0.05). Type I fiber CSA and diameter were increased (P < 0.05) by TBA and RAC. Type I CSA and diameter were larger (P < 0.05) in TBA + RAC than RAC only. Type II fiber CSA and diameter were not affected by TBA (P = 0.48), RAC (P = 0.15), or TBA + RAC (P = 0.60). Satellite cell numbers and fiber-associated nuclei were not affected (P > 0.05) by implant status or ractopamine supplementation. These results indicate that TBA and RAC preferentially increase the size of type I fibers in cull cows.
78 FR 52903 - Humboldt (NV) Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-27

... FURTHER INFORMATION CONTACT: Jeff Ulrich, RAC Designated Federal Official, at 775-352-1215. Individuals.../htnf/rac within 21 days of the meeting. Written comments should be sent to Jeff Ulrich, Designated...
Physiatrist: What Is a Physiatrist?

MedlinePlus

... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy Academy Efforts Coalitions Position Statements ... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy Academy Efforts Coalitions Position Statements ...
75 FR 25199 - Medbow-Routt Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-07

... Act. The purpose of the meeting is orientation and RAC overview for members to the newly established... of Work and Setting Future Agendas; Project Process, Submission Form and Deadline; election of RAC...

American Academy of Physical Medicine and Rehabilitation

MedlinePlus

... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy State Affairs and Legislation Tracking ... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy State Affairs and Legislation Tracking ...
77 FR 48494 - Hiawatha East Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-14

...: Janel Crooks, RAC Coordinator, USDA, Hiawatha National Forest, 820 Rains Drive, Gladstone, Michigan...; attn RAC; 820 Rains Drive, Gladstone, MI 49837, or by email to [email protected] or via facsimile to...
Bruton's tyrosine kinase regulates B cell antigen receptor-mediated JNK1 response through Rac1 and phospholipase C-gamma2 activation.

PubMed

Inabe, Kazunori; Miyawaki, Toshio; Longnecker, Richard; Matsukura, Hiroyoshi; Tsukada, Satoshi; Kurosaki, Tomohiro

2002-03-13

Bruton's tyrosine kinase (Btk) is essential for B cell development and B cell antigen receptor (BCR) function. Recent studies have shown that Btk plays an important role in BCR-mediated c-Jun NH(2)-terminal kinase (JNK) 1 activation; however, the mechanism by which Btk participates in the JNK1 response remains elusive. Here we show that the BCR-mediated Rac1 activation is significantly inhibited by loss of Btk, while this Rac1 activation is not affected by loss of phospholipase C-gamma2 (PLC-gamma2). Since PLC-gamma2 is also required for BCR-mediated JNK1 response, our results suggest that Btk regulates Rac1 pathway as well as PLC-gamma2 pathway, both of which contribute to the BCR-mediated JNK1 response.
Immunohistochemical evalulation of activated Ras and Rac1 as potential downstream effectors of aquaporin-5 in breast cancer in vivo.

PubMed

Jensen, Helene H; Login, Frédéric H; Park, Ji-Young; Kwon, Tae-Hwan; Nejsum, Lene N

2017-11-25

Aberrant levels of aquaporin-5 (AQP5) expression have been observed in several types of cancer, including breast cancer, where AQP5 overexpression is associated with metastasis and poor prognosis. In cultured cancer cells, AQP5 facilitates cell migration and activates Ras signaling. Both increased cell migration and Ras activation are associated with cancer metastasis, but so far it is unknown if AQP5 also affects these processes in vivo. Therefore, we investigated if high AQP5 expression in breast cancer tissue correlated with increased activation of Ras and of Rac1, which is a GTPase also involved in cell migration. This was accomplished by immunohistochemical analysis of invasive ductal carcinoma of breast tissue sections from human patients, followed by qualitative and quantitative correlation analysis between AQP5 and activated Ras and Rac1. Immunohistochemistry revealed that activation of Ras and Rac1 was positively correlated. There was, however, no correlation between high AQP5 expression and activation of Ras, whereas a nonsignificant, but positive, tendency between the levels of AQP5 and activated Rac1 levels was observed. In summary, this is the first report that correlates AQP5 expression levels to downstream signaling partners in breast cancer tissue sections. The results suggest Rac1 as a potential downstream signaling partner of AQP5 in vivo. Copyright © 2017 Elsevier Inc. All rights reserved.
Impact of TiO2 on the chemical and biological transformation of formulated chiral-metalaxyl in agricultural soils.

PubMed

Huang, Junxing; Zhang, Xu; Liang, Chuanzhou; Hu, Jun

2018-04-15

The impacts of TiO 2 on the chemical and biological transformation of racemic metalaxyl wettable powder (rac-metalaxyl WP) in agricultural soils, and soil microorganisms were investigated. Under simulated solar irradiation, TiO 2 highly promoted the transformation of rac-metalaxyl WP without changing the enantiomer fraction, with the promotion amplitude (60-1280%) being dependent on TiO 2 characteristics. TiO 2 characteristics showed different influence on the transformation of rac-metalaxyl WP in soils and aqueous solutions because their characteristics changed differently in soils. The impact of the mancozeb and other co-constituents on the transformation of rac-metalaxyl WP was smaller in soil media than in aqueous solution. Autoclave sterilization changed soil properties and subsequently weakened the promotion effects of TiO 2 on the chemical transformations of rac-metalaxyl WP to 0-233%. Microorganism biomass and bacterial community were not statistically significant changed by TiO 2 exposure regardless of rac-metalaxyl WP, suggesting that the promotional effects occurred mainly through chemical processes. The results also showed TiO 2 -soil interactions may be strengthened with TiO 2 (Degussa P25) aging time in soils, which decreased its promotion amplitude from 1060% (without aging) to 880% (aging for 20 days). Intermediate formed in soil biological transformation process was different from that in TiO 2 photocatalysis process. Copyright © 2018 Elsevier B.V. All rights reserved.
Receptor-like kinases as surface regulators for RAC/ROP-mediated pollen tube growth and interaction with the pistil

PubMed Central

Zou, Yanjiao; Aggarwal, Mini; Zheng, Wen-Guang; Wu, Hen-Ming; Cheung, Alice Y.

2011-01-01

Background RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen tubes depend on continuous interactions with an extracellular environment produced by their surrounding tissues as they grow within the female organ pistil to deliver sperm to the female gametophyte for fertilization. Scope We review studies on pollen tube growth that provide compelling evidence indicating that RAC/ROPs are crucial for regulating the cellular processes that underlie the polarized cell growth process. Efforts to identify cell surface regulators that mediate extracellular signals also point to RAC/ROPs being the molecular switches targeted by growth-regulating female factors for modulation to mediate pollination and fertilization. We discuss a large volume of work spanning more than two decades on a family of pollen-specific receptor kinases and some recent studies on members of the FERONIA family of receptor-like kinases (RLKs). Significance The research described shows the crucial roles that two RLK families play in transducing signals from growth regulatory factors to the RAC/ROP switch at the pollen tube apex to mediate and target pollen tube growth to the female gametophyte and signal its disintegration to achieve fertilization once inside the female chamber. PMID:22476487
Involvement of rho-gtpases in fibroblast adhesion and fibronectine fibrillogenesis under stretch

NASA Astrophysics Data System (ADS)

Guignandon, A.; Lambert, C.; Rattner, A.; Servotte, S.; Lapiere, C.; Nusgens, B.; Vico, L.

The Rho family small GTPases play a crucial role in mediating cellular adaptation to mechanical stimulation (MS), and possibly to microgravity (μg), through effects on the cytoskeleton and cell adhesion which is, in turn, mainly regulated by fibronectin fibrillogenesis (FnF). It remains unclear how mechanical stimulation is transduced to the Rho signaling pathways and how it impacts on fibronectin (fbn) fibrillogenesis (FnF). μg (2 days, mission STS-095) led to de-adhesion of fibroblasts and modification of the underlying extracellular matrix. To determine whether GTPases modulated FnF, we generated stable cell lines expressing high level of activated RhoA and Rac1 (QL) as compared to wild type (WI26-WT). After MS application [8% deformation, 1Hz, 15 min., 3 times/day for 1-2 days], we quantified focal adhesion (vinculin, paxillin, FAKY397), f-actin stress fibers (Sf) and FnF with home-developed softwares. We reported that after MS, Sf are more rapidly (30min) formed under the nucleus in Wi26-WT (+100%) and Rac1 (+200%) than in RhoA (+20%). Vinculin & paxillin were only restricted to the cell edge in static conditions and homogeneously distributed after MS in WT and Rac1. The relative area of contacts (vinculin & paxillin) was more dramatically enhanced by MS in Rac1 (+80%) than in WT (+40%) and RhoA (+25%) indicating that new focal contacts are formed under MS and supported the presence of Sf. MS Activation of FAK (FAKY397) was clear in WT and Rac1 and reduced in RhoA. FnF was restricted to cell-cell contacts zone without any change in the relative area of fbn after a 2-days MS. However we found more numerous spots of fbn at the cell center in Rac1 as compared with RhoA & WT suggesting that these fibrillar contacts will grow upon maturation and modulate FnF. The results indicate that MS induces formation of Sf and focal adhesions and enhances FF. RhoA has been shown to induce the formation of Sf and focal adhesions, and Rac1 activation decreases Rho activity in some cell types. As the sensitivity to MS is Rac1>WI-26>RhoA we speculate (1) that MS increases RhoA activity, and (2) that this effect is more prominent in Rac1 cells due to an induced lower basal level of RhoA activity. This study is a feasibility work for future space missions allowing evaluating the effect of μg on our models.
Use of electromyography to detect muscle exhaustion in finishing barrows fed ractopamine HCl.

PubMed

Noel, J A; Broxterman, R M; McCoy, G M; Craig, J C; Phelps, K J; Burnett, D D; Vaughn, M A; Barstow, T J; O'Quinn, T G; Woodworth, J C; DeRouchey, J M; Rozell, T G; Gonzalez, J M

2016-06-01

The objectives of this study were to determine the effects of dietary ractopamine HCl (RAC) on muscle fiber characteristics and electromyography (EMG) measures of finishing barrow exhaustion when barrows were subjected to increased levels of activity. Barrows ( = 34; 92 ± 2 kg initial BW) were assigned to 1 of 2 treatments: a conventional swine finishing diet containing 0 mg/kg ractopamine HCl (CON) or a diet formulated to meet the requirements of finishing barrows fed 10 mg/kg RAC (RAC+). After 32 d on feed, barrows were individually moved around a track at 0.79 m/s until subjectively exhausted. Wireless EMG sensors were affixed to the deltoideus (DT), triceps brachii lateral head (TLH), tensor fasciae latae (TFL), and semitendinosus (ST) muscles to measure median power frequency (MdPF) and root mean square (RMS) as indicators of action potential conduction velocity and muscle fiber recruitment, respectively. After harvest, samples of each muscle were collected for fiber type, succinate dehydrogenase (SDH), and capillary density analysis. Speed was not different ( = 0.82) between treatments, but RAC+ barrows reached subjective exhaustion earlier and covered less distance than CON barrows ( < 0.01). There were no treatment × muscle interactions or treatment effects for end-point MdPF values ( > 0.29). There was a treatment × muscle interaction ( = 0.04) for end-point RMS values. The RAC diet did not change end-point RMS values in the DT or TLH ( > 0.37); however, the diet tended to decrease and increase end-point RMS in the ST and TFL, respectively ( < 0.07). There were no treatment × muscle interactions for fiber type, SDH, or capillary density measures ( > 0.10). Muscles of RAC+ barrows tended to have less type I fibers and more capillaries per fiber ( < 0.07). Type I and IIA fibers of RAC+ barrows were larger ( < 0.07). Compared with all other muscles, the ST had more ( < 0.01) type IIB fibers and larger type I, IIA, and IIX fibers ( < 0.01). Type I, IIA, and IIX fibers of the ST also contained less SDH compared with the other muscles ( < 0.01). Barrows fed a RAC diet had increased time to subjective exhaustion due to loss of active muscle fibers in the ST, possibly due to fibers being larger and less oxidative in metabolism. Size increases in type I and IIA fibers with no change in oxidative capacity could also contribute to early exhaustion of RAC+ barrows. Overall, EMG technology can measure real-time muscle fiber loss to help explain subjective exhaustion in barrows.
Ratiometric Imaging Using a Single Dye Enables Simultaneous Visualization of Rac1 and Cdc42 Activation.

PubMed

MacNevin, Christopher J; Toutchkine, Alexei; Marston, Daniel J; Hsu, Chia-Wen; Tsygankov, Denis; Li, Li; Liu, Bei; Qi, Timothy; Nguyen, Dan-Vinh; Hahn, Klaus M

2016-03-02

Biosensors that report endogenous protein activity in vivo can be based on environment-sensing fluorescent dyes. The dyes can be attached to reagents that bind selectively to a specific conformation of the targeted protein, such that binding leads to a fluorescence change. Dyes that are sufficiently bright for use at low, nonperturbing intracellular concentrations typically undergo changes in intensity rather than the shifts in excitation or emission maxima that would enable precise quantitation through ratiometric imaging. We report here mero199, an environment-sensing dye that undergoes a 33 nm solvent-dependent shift in excitation. The dye was used to generate a ratiometric biosensor of Cdc42 (CRIB199) without the need for additional fluorophores. CRIB199 was used in the same cell with a FRET sensor of Rac1 activation to simultaneously observe Cdc42 and Rac1 activity in cellular protrusions, indicating that Rac1 but not Cdc42 activity was reduced during tail retraction, and specific protrusions had reduced Cdc42 activity. A novel program (EdgeProps) used to correlate localized activation with cell edge dynamics indicated that Rac1 was specifically reduced during retraction.
The Molecular Motor KIF21B Mediates Synaptic Plasticity and Fear Extinction by Terminating Rac1 Activation.

PubMed

Morikawa, Momo; Tanaka, Yosuke; Cho, Hyun-Soo; Yoshihara, Masaharu; Hirokawa, Nobutaka

2018-06-26

Fear extinction is a component of cognitive flexibility that is relevant for important psychiatric diseases, but its molecular mechanism is still largely elusive. We established mice lacking the kinesin-4 motor KIF21B as a model for fear extinction defects. Postsynaptic NMDAR-dependent long-term depression (LTD) is specifically impaired in knockouts. NMDAR-mediated LTD-causing stimuli induce dynamic association of KIF21B with the Rac1GEF subunit engulfment and cell motility protein 1 (ELMO1), leading to ELMO1 translocation out of dendritic spines and its sequestration in endosomes. This process may essentially terminate transient activation of Rac1, shrink spines, facilitate AMPAR endocytosis, and reduce postsynaptic strength, thereby forming a mechanistic link to LTD expression. Antagonizing ELMO1/Dock Rac1GEF activity by the administration of 4-[3'-(2″-chlorophenyl)-2'-propen-1'-ylidene]-1-phenyl-3,5-pyrazolidinedione (CPYPP) significantly reverses the knockout phenotype. Therefore, we propose that KIF21B-mediated Rac1 inactivation is a key molecular event in NMDAR-dependent LTD expression underlying cognitive flexibility in fear extinction. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.
Myosin IIA/IIB restrict adhesive and protrusive signaling to generate front-back polarity in migrating cells.

PubMed

Vicente-Manzanares, Miguel; Newell-Litwa, Karen; Bachir, Alexia I; Whitmore, Leanna A; Horwitz, Alan Rick

2011-04-18

Migratory front-back polarity emerges from the cooperative effect of myosin IIA (MIIA) and IIB (MIIB) on adhesive signaling. We demonstrate here that, during polarization, MIIA and MIIB coordinately promote localized actomyosin bundling, which generates large, stable adhesions that do not signal to Rac and thereby form the cell rear. MIIA formed dynamic actomyosin proto-bundles that mark the cell rear during spreading; it also bound to actin filament bundles associated with initial adhesion maturation in protrusions. Subsequent incorporation of MIIB stabilized the adhesions and actomyosin filaments with which it associated and formed a stable, extended rear. These adhesions did not turn over and no longer signal to Rac. Microtubules fine-tuned the polarity by positioning the front opposite the MIIA/MIIB-specified rear. Decreased Rac signaling in the vicinity of the MIIA/MIIB-stabilized proto-bundles and adhesions was accompanied by the loss of Rac guanine nucleotide exchange factor (GEFs), like βPIX and DOCK180, and by inhibited phosphorylation of key residues on adhesion proteins that recruit and activate Rac GEFs. These observations lead to a model for front-back polarity through local GEF depletion.
Identification of a Polyomavirus microRNA Highly Expressed in Tumors

PubMed Central

Chen, Chun Jung; Cox, Jennifer E.; Azarm, Kristopher; Wylie, Karen N.; Woolard, Kevin D.; Pesavento, Patricia A.; Sullivan, Christopher S.

2014-01-01

Polyomaviruses (PyVs) are associated with tumors including Merkel cell carcinoma (MCC). Several PyVs encode microRNAs (miRNAs) but to date no abundant PyV miRNAs have been reported in tumors. To better understand the function of the Merkel cell PyV (MCPyV) miRNA, we examined phylogenetically-related viruses for miRNA expression. We show that two primate PyVs and the more distantly-related raccoon PyV (RacPyV) encode miRNAs that share genomic position and partial sequence identity with MCPyV miRNAs. Unlike MCPyV miRNA in MCC, RacPyV miRNA is highly abundant in raccoon tumors. RacPyV miRNA negatively regulates reporters of early viral (T antigen) transcripts, yet robust viral miRNA expression is tolerated in tumors. We also identify raccoon miRNAs expressed in RacPyV-associated neuroglial brain tumors, including several likely oncogenic miRNAs (oncomiRs). This work describes the first PyV miRNA abundantly expressed in tumors and is consistent with a possible role for both host and viral miRNAs in RacPyV-associated tumors. PMID:25514573
Acute alcohol intoxication-induced microvascular leakage.

PubMed

Doggett, Travis M; Breslin, Jerome W

2014-09-01

Alcohol intoxication can increase inflammation and worsen injury, yet the mechanisms involved are not clear. We investigated whether acute alcohol intoxication increases microvascular permeability and investigated potential signaling mechanisms in endothelial cells that may be involved. Conscious rats received a 2.5 g/kg alcohol bolus via gastric catheters to produce acute intoxication. Microvascular leakage of intravenously administered fluorescein isothiocyanate (FITC)-conjugated albumin (FITC-albumin) from the mesenteric microcirculation was assessed by intravital microscopy. Endothelial-specific mechanisms were studied using cultured endothelial cell monolayers. Transendothelial electrical resistance (TER) served as an index of barrier function, before and after treatment with alcohol or its metabolite acetaldehyde. Pharmacologic agents were used to test the roles of alcohol metabolism, oxidative stress, p38 mitogen-activated protein kinase (MAPK), myosin light-chain kinase (MLCK), rho kinase (ROCK), and exchange protein activated by cAMP (Epac). VE-cadherin localization was investigated to assess junctional integrity. Rac1 and RhoA activation was assessed by ELISA assays. Alcohol significantly increased FITC-albumin extravasation from the mesenteric microcirculation. Alcohol also significantly decreased TER and disrupted VE-cadherin organization at junctions. Acetaldehyde significantly decreased TER, but inhibition of alcohol dehydrogenase or application of a superoxide dismutase mimetic failed to prevent alcohol-induced decreases in TER. Inhibition of p38 MAPK, but not MLCK or ROCK, significantly attenuated the alcohol-induced barrier dysfunction. Alcohol rapidly decreased GTP-bound Rac1 but not RhoA during the drop in TER. Activation of Epac increased TER, but did not prevent alcohol from decreasing TER. However, activation of Epac after initiation of alcohol-induced barrier dysfunction quickly resolved TER to baseline levels. Our results suggest that alcohol intoxication increases microvascular permeability to plasma proteins. The data also suggest the endothelial-specific mechanism involves the p38 MAPK, Rac1, and reorganization of VE-cadherin at junctions. Last, activation of Epac can quickly resolve alcohol-induced endothelial barrier dysfunction. Copyright © 2014 by the Research Society on Alcoholism.
[Regional ophthalmological cluster as a resource basis for the process and the procedure of specialist accreditation].

PubMed

Chukhraev, A M; Khodzhaev, N S; Malyugin, B E; Doga, A V; Zabolotniy, A G

Since 2016, phased introduction of specialist accreditation has been launched. Many issues like how training at regional accreditation centers (RACs) should be organized - for applicants applying for primary specialized accreditation as residents in ophthalmology (2018) or periodic accreditation as practicing ophthalmologists (2021) - are yet debatable. to provide organizational and educational resources for arranging accreditation of ophthalmologists at the background of improving the quality of medical care in a federal subject of the Russian Federation. The study object was the process and the procedure of accreditation, the study subject - the system of specialist accreditation. bibliographical, analytical, and expert. Methodological basis for tasks solving: mobilization of an independent organizational structure, that is, the regional ophthalmological scientific-educational cluster (ROSEC). Three complex problems have been defined that require solution. 1. Discrepancies between accreditation procedures depending on the type of accreditation. The absence of practical skills assessment within the periodical accreditation procedure and low availability of innovative simulation systems impede the achievement of the declared goals of accreditation. 2. The absence of a clear order and criteria for portfolio assessment as well as a legal format of its formation during non-interrupted medical education (NIME) demands active management. 3. There is still a lack of appropriate organizational, educational, material technical, and personnel support of the accreditation system. The proposed organizational and methodological approaches are aimed at solving issues of accreditation support, proper functioning of RACs, and improving the quality and regional availability of NIME. Systematic approach effectively solves the problem of resource support of accreditation. ROSEC should be regarded as the provision basis for complex of all stages of ophthalmologist accreditation and proper functioning of RACs. ROSEC involvement is highly advisable.
Rubberized asphalt concrete warranty pilot projects.

DOT National Transportation Integrated Search

2005-11-01

Between 2002 and 2004 Caltrans built five pilot projects through its rehabilitation program that contain : specifications for rubberized asphalt concrete (RAC) overlay and include a 5-year warranty on the RAC : materials and workmanship. The overall ...
76 FR 22863 - Kern and Tulare Counties Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-25

... are to contact the Designated Federal Official, Priscilla Summers at the Western Divide Ranger... related matters to the attention of the RAC may file written statements with the RAC staff before or after...
77 FR 46681 - Shasta County Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-06

... Schools one-year extension to the 2008-2011 RAC authorization, and recruitment of new RAC Committee... recruitment. An agenda of the meeting is also available at http://www.fs.usda.gov/main/stnf/workingtogether...
Overview of NASA Glenn Research Center Programs in Aero-Heat Transfer and Future Needs

NASA Technical Reports Server (NTRS)

Gaugler, Raymond E.

2002-01-01

This presentation concentrates on an overview of the NASA Glenn Research Center and the projects that are supporting Turbine Aero-Heat Transfer Research. The principal areas include the Ultra Efficient Engine Technology (UEET) Project, the Advanced Space Transportation Program (ASTP) Revolutionary Turbine Accelerator (RTA) Turbine Based Combined Cycle (TBCC) project, and the Propulsion & Power Base R&T - Smart Efficient Components (SEC), and Revolutionary Aeropropulsion Concepts (RAC) Projects. In addition, highlights are presented of the turbine aero-heat transfer work currently underway at NASA Glenn, focusing on the use of the Glenn-HT Navier- Stokes code as the vehicle for research in turbulence & transition modeling, grid topology generation, unsteady effects, and conjugate heat transfer.
Effects of supplementing zinc or chromium to finishing steers fed ractopamine hydrochloride on growth performance, carcass characteristics, and meat quality.

PubMed

Edenburn, B M; Kneeskern, S G; Bohrer, B M; Rounds, W; Boler, D D; Dilger, A C; Felix, T L

2016-02-01

Objectives were to determine the effects of feeding ractopamine hydrochloride (RAC) with zinc (Zn) and chromium (Cr) on feedlot growth performance, carcass characteristics, and meat quality. Steers ( = 179; initial BW = 533 ± 94 kg) were blocked by BW and allotted to 30 pens, and pens were randomly assigned 1 of 5 treatments: (1) control (CONT), (2) RAC only (RO), (3) RAC + Zn (RZ), (4) RAC + Cr (RC), or (5) RAC + Zn + Cr (RZC). Trace minerals were fed from d 0 to 63 to target 1 g of Zn/steer·d (KemTRACE Zn; Kemin Industries, Inc., Des Moines, IA) and 3 mg Cr/steer·d (KemTRACE Chromium; Kemin Industries, Inc.) for Zn and Cr treatments, respectively. Dry-rolled corn, 0.605 kg/steer, was removed from the diet and 400 mg RAC, per 0.605 kg of ground corn carrier, was top dressed per steer immediately following feed delivery to pens fed RAC. There were no effects ( ≥ 0.45) of trace mineral supplementation on DMI, ADG, or G:F before RAC feeding. There were also no treatment effects ( ≥ 0.46) over all 63 d of the trial on DMI, ADG, or G:F. Despite the lack of differences in live performance, steers fed RO and RC averaged 0.10 kg/d greater ( = 0.10) carcass ADG than steers fed RZC and CONT, while steers fed RZ were intermediate and not different. Steers fed RO had the greatest ( = 0.09) carcass G:F, while steers fed CONT had the least carcass G:F, 0.0875 and 0.0774, respectively. Steers fed RO and RC averaged 5.5 kg heavier ( = 0.09) HCW than steers fed RZC and CONT, while steers fed RZ were intermediate and not different. There were no treatment effects ( ≥ 0.32) on LM area, 12th rib fat, marbling score, KPH, carcass yield, or USDA yield grade and distribution. However, carcasses from steers fed RC had the greatest ( = 0.10) percentage grading USDA Select. There were no treatment effects ( ≥ 0.20) on shear force, intramuscular fat, pH, a*, and b*. Steaks from steers fed RO and RC had 11.4% greater ( = 0.08) cook loss than steaks from steers fed CONT and RZC, whereas steaks from steers fed RZ were intermediate and not different. Also, steaks from steers fed RC had 2.11 units greater ( = 0.03) L* values (i.e., were lighter) than steaks from steers fed RZ; steaks from steers fed CONT, RO, and RZC were intermediate. In feedlot steers, the addition of both Cr and Zn supplementation did not improve growth performance or meat quality when fed in combination with 28 d of RAC supplementation; however, RAC, fed alone or in combination with Cr, did increase HCW.
Comparative Genomic Sequencing and Pathogenic Properties of Equine Herpesvirus 1 KyA and RacL11

PubMed Central

Shakya, Akhalesh K.; O’Callaghan, Dennis J.; Kim, Seong K.

2017-01-01

Equine herpesvirus 1 (EHV-1) is a major pathogen affecting equines worldwide. The virus causes respiratory disease, abortion, and, in some cases, neurological disease. EHV-1 Kentucky A (KyA) is attenuated in the mouse and equine, whereas wild-type pathogenic strain RacL11 induces severe inflammatory infiltration of the lung, causing infected mice to succumb. The complete DNA sequencing of the KyA genome revealed that genes UL17 (ORF17), US6 (ORF73; gI), US7 (ORF74; gE), and US8 (ORF75; 10 K) are deleted as compared to the RacL11 and Ab4 genomes. In-frame deletions in the US1 (ORF68), US4 (ORF71; gp2), and UL63 (ORF63; EICP0) genes and point mutations in 14 different open reading frames (ORFs) were detected in the KyA genome. Interestingly, UL1 (ORF1) and UL2 (ORF2) were deleted in both KyA and RacL11. Our previous studies showed that EHV-1 glycoproteins gI, gE, and full-length gp2 contribute to the pathogenesis of the RacL11 strain. The confirmation of these gene deletions in KyA suggests their contribution to the attenuation of this virus. The growth kinetics results revealed that KyA replicates to high titers in cell culture as compared to RacL11 and Ab4, indicating that the above genomic deletions and mutations in KyA do not have an inhibitory effect on KyA replication in cells of mouse, rabbit, equine, or human origin. Studies of EHV-1 pathogenesis in CBA mice showed that KyA is attenuated whereas mice infected with RacL11 succumbed by 3–6 days post-infection, which is consistent with our previous results. PMID:29312962

The Impact of Electronic Health Records on Risk Management of Information Systems in Australian Residential Aged Care Homes.

PubMed

Jiang, Tao; Yu, Ping; Hailey, David; Ma, Jun; Yang, Jie

2016-09-01

To obtain indications of the influence of electronic health records (EHR) in managing risks and meeting information system accreditation standard in Australian residential aged care (RAC) homes. The hypothesis to be tested is that the RAC homes using EHR have better performance in meeting information system standards in aged care accreditation than their counterparts only using paper records for information management. Content analysis of aged care accreditation reports from the Aged Care Standards and Accreditation Agency produced between April 2011 and December 2013. Items identified included types of information systems, compliance with accreditation standards, and indicators of failure to meet an expected outcome for information systems. The Chi-square test was used to identify difference between the RAC homes that used EHR systems and those that used paper records in not meeting aged care accreditation standards. 1,031 (37.4%) of 2,754 RAC homes had adopted EHR systems. Although the proportion of homes that met all accreditation standards was significantly higher for those with EHR than for homes with paper records, only 13 RAC homes did not meet one or more expected outcomes. 12 used paper records and nine of these failed the expected outcome for information systems. The overall contribution of EHR to meeting aged care accreditation standard in Australia was very small. Risk indicators for not meeting information system standard were no access to accurate and appropriate information, failure in monitoring mechanisms, not reporting clinical incidents, insufficient recording of residents' clinical changes, not providing accurate care plans, and communication processes failure. The study has provided indications that use of EHR provides small, yet significant advantages for RAC homes in Australia in managing risks for information management and in meeting accreditation requirements. The implication of the study for introducing technology innovation in RAC in Australia is discussed.
Robotic-assisted colorectal surgery in the United States: a nationwide analysis of trends and outcomes.

PubMed

Halabi, Wissam J; Kang, Celeste Y; Jafari, Mehraneh D; Nguyen, Vinh Q; Carmichael, Joseph C; Mills, Steven; Stamos, Michael J; Pigazzi, Alessio

2013-12-01

While robotic-assisted colorectal surgery (RACS) is becoming increasingly popular, data comparing its outcomes to other established techniques remain limited to small case series. Moreover, there are no large studies evaluating the trends of RACS at the national level. The Nationwide Inpatient Sample 2009-2010 was retrospectively reviewed for robotic-assisted and laparoscopic colorectal procedures performed for cancer, benign polyps, and diverticular disease. Trends in different settings, indications, and demographics were analyzed. Multivariate regression analysis was used to compare selected outcomes between RACS and conventional laparoscopic surgery (CLS). An estimated 128,288 colorectal procedures were performed through minimally invasive techniques over the study period, and RACS was used in 2.78 % of cases. From 2009 to 2010, the use of robotics increased in all hospital settings but was still more common in large, urban, and teaching hospitals. Rectal cancer was the most common indication for RACS, with a tendency toward its selective use in male patients. On multivariate analysis, robotic surgery was associated with higher hospital charges in colonic ($11,601.39; 95 % CI 6,921.82-16,280.97) and rectal cases ($12,964.90; 95 % CI 6,534.79-19,395.01), and higher rates of postoperative bleeding in colonic cases (OR = 2.15; 95 % CI 1.27- 3.65). RACS was similar to CLS with respect to length of hospital stay, morbidity, anastomotic leak, and ileus. Conversion to open surgery was significantly lower in robotic colonic and rectal procedures (0.41; 95 % CI 0.25-0.67) and (0.10; 95 % CI 0.06-0.16), respectively. The use of RACS is still limited in the United States. However, its use increased over the study period despite higher associated charges and no real advantages over laparoscopy in terms of outcome. The one advantage is lower conversion rates.
75 FR 8397 - Notice of Utah's Resource Advisory Council (RAC)/Recreation RAC Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

....--5 p.m.) in St. George, Utah. ADDRESSES: The Council will meet at the Hilton Garden Inn (Indigo... Commissioners' and School and Institutional Trust Lands Administration's perspectives on the Act. Randy Johnson...
78 FR 33102 - Third Call for Nominations for Resource Advisory Councils

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-03

... RACs provide advice and recommendations to the BLM on land use planning for management of the National System of Public Lands within their respective geographic areas. The RACs covered by this request for...
WAVE2 deficiency reveals distinct roles in embryogenesis and Rac-mediated actin-based motility

PubMed Central

Yan, Catherine; Martinez-Quiles, Narcisa; Eden, Sharon; Shibata, Tomoyuki; Takeshima, Fuminao; Shinkura, Reiko; Fujiwara, Yuko; Bronson, Roderick; Snapper, Scott B.; Kirschner, Marc W.; Geha, Raif; Rosen, Fred S.; Alt, Frederick W.

2003-01-01

The Wiskott–Aldrich syndrome related protein WAVE2 is implicated in the regulation of actin-cytoskeletal reorganization downstream of the small Rho GTPase, Rac. We inactivated the WAVE2 gene by gene-targeted mutation to examine its role in murine development and in actin assembly. WAVE2-deficient embryos survived until approximately embryonic day 12.5 and displayed growth retardation and certain morphological defects, including malformations of the ventricles in the developing brain. WAVE2-deficient embryonic stem cells displayed normal proliferation, whereas WAVE2-deficient embryonic fibroblasts exhibited severe growth defects, as well as defective cell motility in response to PDGF, lamellipodium formation and Rac-mediated actin polymerization. These results imply a non-redundant role for WAVE2 in murine embryogenesis and a critical role for WAVE2 in actin-based processes downstream of Rac that are essential for cell movement. PMID:12853475
Wave2 activates serum response element via its VCA region and functions downstream of Rac.

PubMed

Ishiguro, Kazuhiro; Cao, Zhifang; Ilasca, Marco Lopez; Ando, Takafumi; Xavier, Ramnik

2004-12-10

WAVE2 is a member of the WASP/WAVE family of protein effectors of actin reorganization and cell movement. In this report, we demonstrate that WAVE2 overexpression induces serum response element (SRE) activation through serum response factor. A WAVE2 mutant lacking the VCA region did not induce SRE activation and actin polymerization. WAVE2-induced SRE activation was blocked by exposure of cells to Latrunculin A, or overexpression of actin mutant R62D. The DeltaVCA mutant inhibited Rac V12-induced SRE activation, suggesting that WAVE2 lies downstream of Rac. Similar deletion of the VCA domain of WASP attenuated Cdc42 V12-mediated SRE activation, suggesting that WAVE2 acts in relation to Rac as WASP acts in relation to Cdc42. WAVE2 overexpression did not activate NF-kappaB.
WAVE2 deficiency reveals distinct roles in embryogenesis and Rac-mediated actin-based motility.

PubMed

Yan, Catherine; Martinez-Quiles, Narcisa; Eden, Sharon; Shibata, Tomoyuki; Takeshima, Fuminao; Shinkura, Reiko; Fujiwara, Yuko; Bronson, Roderick; Snapper, Scott B; Kirschner, Marc W; Geha, Raif; Rosen, Fred S; Alt, Frederick W

2003-07-15

The Wiskott-Aldrich syndrome related protein WAVE2 is implicated in the regulation of actin-cytoskeletal reorganization downstream of the small Rho GTPase, Rac. We inactivated the WAVE2 gene by gene-targeted mutation to examine its role in murine development and in actin assembly. WAVE2-deficient embryos survived until approximately embryonic day 12.5 and displayed growth retardation and certain morphological defects, including malformations of the ventricles in the developing brain. WAVE2-deficient embryonic stem cells displayed normal proliferation, whereas WAVE2-deficient embryonic fibroblasts exhibited severe growth defects, as well as defective cell motility in response to PDGF, lamellipodium formation and Rac-mediated actin polymerization. These results imply a non-redundant role for WAVE2 in murine embryogenesis and a critical role for WAVE2 in actin-based processes downstream of Rac that are essential for cell movement.
Selective effect of myclobutanil enantiomers on fungicidal activity and fumonisin production by Fusarium verticillioides under different environmental conditions.

PubMed

Li, Na; Deng, Luqing; Li, Jianfang; Wang, Zhengbing; Han, Yiye; Liu, Chenglan

2018-05-01

Myclobutanil is a widely used triazole fungicide, comprising two enantiomers with different fungicidal activities, non-target toxicities, and environmental fates. The enantioselective effects of myclobutanil on fumonisin B (FB) production by Fusarium verticillioides, an important pathogen, have not yet been investigated. In the present study, the fungicidal activities of rac-myclobutanil and its enantiomers on F. verticillioides cultured on maize-based media were studied under different water activity and temperature conditions. The FB levels were measured to assess the enantioselective effects on FB production when F. verticillioides were cultured treated with EC 50 and EC 90 concentrations (concentrations inhibiting mycelial growth by 50.0% and 90.0%, respectively) of myclobutanil and enantiomers under different conditions. The fungicidal activities of rac-myclobutanil and its enantiomers decreased with increasing temperature and decreasing water activity. Little difference in fungicidal activity was observed between the enantiomers. FB production was significantly influenced by temperature, a w , and fungicides dose. At EC50 concentrations, rac-myclobutantil and its enantiomers were shown to enhance mycotoxin production and enantioselective effects of enantiomers on FB production were observed under certain conditions. This is the first report on the differential effects of myclobutanil enantiomers on the control of F. verticillioides growth and FB production in maize-based media under different conditions. Copyright © 2018 Elsevier Inc. All rights reserved.
Pharmacogenetics of esomeprazole or rabeprazole-based triple therapy in Helicobacter pylori eradication in Hong Kong non-ulcer dyspepsia Chinese subjects.

PubMed

Lee, V W Y; Chau, T S; Chan, A K W; Lee, K K C; Waye, M M Y; Ling, T K W; Chan, F K L

2010-06-01

Our study aimed to assess the effectiveness of esomeprazole or rabeprazole in combination with amoxicillin and clarithromycin for the eradication of Helicobacter pylori in Hong Kong non-ulcer dyspepsia (NUD) patients. A prospective clinical trial was conducted at the Alice Ho Miu ling Nethersole Hospital outpatient endoscopy center from June 2004 to December 2005. Participants received amoxicillin 1 g, clarithromycin 500 mg, and, esomeprazole 20 mg (EAC) or rabeprazole 20 mg (RAC), all given twice daily for 1 week. The H. pylori status was determined by the [13C] urea breath test at least 4 weeks after completion of the treatment. Mutation status of CYP2C19 in exon 4 and exon 5 associated with the poor metabolizer phenotype was determined. The intention-to-treat eradication rates in patients treated with RAC and EAC were 77% and 84.6% respectively, and per protocol-based eradication rates were 83.7% and 88.9% respectively. The eradication rates did not vary with CYP2C19 phenotype found. For clarithromycin-sensitive strains, the cure rates were statistically significant regardless of CYP2C19 polymorphism (P < 0.0001). Triple therapy with either EAC or RAC is effective for Hong Kong Chinese NUD patients with H. pylori infection. Success eradication was related to clarithromycin resistance and not CYP2C19 genotype.
A critical role for phosphatidylinositol (3,4,5)-trisphosphate-dependent Rac exchanger 1 in endothelial junction disruption and vascular hyperpermeability

PubMed Central

Naikawadi, Ram P.; Cheng, Ni; Vogel, Stephen M.; Qian, Feng; Wu, Dianqing; Malik, Asrar B.; Ye, Richard D.

2013-01-01

Rationale The small GTPase Rac is critical to vascular endothelial functions, yet its regulation in endothelial cells remains unclear. Understanding the upstream pathway may delineate Rac activation mechanisms and its role in maintaining vascular endothelial barrier integrity. Objective By investigating P-Rex1, one of the Rac-specific guanine nucleotide exchange factors (GEFs) previously known for G protein-coupled receptor (GPCR) signaling, we sought to determine whether Rac-GEF is a nodal for signal integration and potential target for drug intervention. Methods and Results Using gene deletion and siRNA silencing approach, we investigated the role of P-Rex1 in lung microvascular endothelial cells (HLMVECs). TNF-α exposure led to disruption of endothelial junctions, and silencing P-Rex1 protected junction integrity. TNF-α stimulated Rac activation and ROS production in a P-Rex1-dependent manner. Removal of P-Rex1 significantly reduced ICAM-1 expression, PMN transendothelial migration and leukocyte sequestration in TNF-α challenged mouse lungs. The P-Rex1 knockout mice were also refractory to lung vascular hyper-permeability and edema in a LPS-induced sepsis model. Conclusions These results demonstrate for the first time that P-Rex1 expressed in endothelial cells is activated downstream of TNF-α, which is not a GPCR agonist. Our data identify P-Rex1 as a critical mediator of vascular barrier disruption. Targeting P-Rex1 may effectively protect against TNF-α and LPS-induced endothelial junction disruption and vascular hyper-permeability. PMID:22965143
Structural characterization of 1,3-propanedithiols that feature carboxylic acids: Homologues of mercury chelating agents ✩

PubMed Central

Sattler, Wesley; Palmer, Joshua H.; Bridges, Christy C.; Joshee, Lucy; Zalups, Rudolfs K.; Parkin, Gerard

2013-01-01

The molecular structures of a series of 1,3-propanedithiols that contain carboxylic acid groups, namely rac- and meso-2,4-dimercaptoglutaric acid (H4DMGA) and 2-carboxy-1,3-propanedithiol (H3DMCP), have been determined by X-ray diffraction. Each compound exhibits two centrosymmetric intermolecular hydrogen bonding interactions between pairs of carboxylic acid groups, which result in a dimeric structure for H3DMCP and a polymeric tape-like structure for rac- and meso-H4DMGA. Significantly, the hydrogen bonding motifs observed for rac- and meso-H4DMGA are very different to those observed for the 1,2-dithiol, rac-2,3-dimercaptosuccinic acid (rac-H4DMSA), in which the two oxygen atoms of each carboxylic acid group hydrogen bond to two different carboxylic acid groups, thereby resulting in a hydrogen bonded sheet-like structure rather than a tape. Density functional theory calculations indicate that 1,3-dithiolate coordination to mercury results in larger S–Hg–S bond angles than does 1,2-dithiolate coordination, but these angles are far from linear. As such, κ2-S2 coordination of these dithiolate ligands is expected to be associated with mercury coordination numbers of greater than two. In vivo studies demonstrate that both rac-H4DMGA and H3DMCP reduce the renal burden of mercury in rats, although the compounds are not as effective as either 2,3-dimercaptopropane-1-sulfonic acid (H3DMPS) or meso-H4DMSA. PMID:24187425
Region-specific role of Rac in nucleus accumbens core and basolateral amygdala in consolidation and reconsolidation of cocaine-associated cue memory in rats.

PubMed

Ding, Zeng-Bo; Wu, Ping; Luo, Yi-Xiao; Shi, Hai-Shui; Shen, Hao-Wei; Wang, Shen-Jun; Lu, Lin

2013-08-01

Drug reinforcement and the reinstatement of drug seeking are associated with the pathological processing of drug-associated cue memories that can be disrupted by manipulating memory consolidation and reconsolidation. Ras-related C3 botulinum toxin substrate (Rac) is involved in memory processing by regulating actin dynamics and neural structure plasticity. The nucleus accumbens (NAc) and amygdala have been implicated in the consolidation and reconsolidation of emotional memories. Therefore, we hypothesized that Rac in the NAc and amygdala plays a role in the consolidation and reconsolidation of cocaine-associated cue memory. Conditioned place preference (CPP) and microinjection of Rac inhibitor NSC23766 were used to determine the role of Rac in the NAc and amygdala in the consolidation and reconsolidation of cocaine-associated cue memory in rats. Microinjections of NSC23766 into the NAc core but not shell, basolateral (BLA), or central amygdala (CeA) after each cocaine-conditioning session inhibited the consolidation of cocaine-induced CPP. A microinjection of NSC23766 into the BLA but not CeA, NAc core, or NAc shell immediately after memory reactivation induced by exposure to a previously cocaine-paired context disrupted the reconsolidation of cocaine-induced CPP. The effect of memory disruption on cocaine reconsolidation was specific to reactivated memory, persisted at least 2 weeks, and was not reinstated by a cocaine-priming injection. Our findings indicate that Rac in the NAc core and BLA are required for the consolidation and reconsolidation of cocaine-associated cue memory, respectively.
SH3BP1-induced Rac-Wave2 pathway activation regulates cervical cancer cell migration, invasion, and chemoresistance to cisplatin.

PubMed

Wang, Jingjing; Feng, Yeqian; Chen, Xishan; Du, Zheng; Jiang, Shaijun; Ma, Shuyun; Zou, Wen

2018-02-01

Cervical cancer still remains the fourth most common cancer, affecting women worldwide with large geographic variations in cervical cancer incidence and mortality rates. SH3-domain binding protein-1 (SH3BP1) specifically inactivating Rac1 and its target Wave2 is required for cell motility, thus regarded as an essential regulator of cancer cell metastasis. However, the exact effects and molecular mechanisms of SH3BP1 in cervical cancer progression are still unknown. The present study is aimed to investigate the mechanism of SH3BP1 in regulation of cervical cancer cell metastasis and chemoresistance. In the present study, we demonstrated a high SH3BP1 expression in cervical cancer tissues; a higher SH3BP1 expression is also correlated with a shorter overall survival of patients with cervical cancer. Further, we revealed that SH3BP1 overexpression promoted the invasion, migration, and chemoresistance of cervical cancer cell through increasing Rac1 activity and Wave2 protein level. The promotive effect of SH3BP1 could be partially reversed by a Rac1 inhibitor, NSC 23766. In cisplatin-resistant cervical cancer tissues, SH3BP1, Rac1, and Wave2 mRNA expression was significantly up-regulated compared to that of the cisplatin-sensitive cervical cancer tissues. Taken together, SH3BP1/Rac1/Wave2 pathway may potentially act as an effective therapeutic target combined with traditional cisplatin-based chemotherapy for cervical cancer. © 2017 Wiley Periodicals, Inc.
78 FR 5489 - Notice of Utah's Recreation Resource Advisory Council/Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

... for Utah public lands within the BLM's National Landscape Conservation System; and the RAC's involvement with the Utah Film Commission. On February 22, the RecRAC will listen to fee presentations from...
In Situ Evaluation of the Role of the Small GTPase Rac3 in Breast Cancer

DTIC Science & Technology

2005-07-01

in Figure 3a, total endogenous Rae protein expression remained equal among the cell variants. However, levels of active Rae ranged from highest in the...variants. a b Whole cell lysates of variants were 00 46M 4k& Total Rac Total Cdc42 subjected to SDS-PAGE followed by M -W Active Ra [ Active Cdc42 western...blot analysis for total Rac (a) 4o1o1....0 ........GTPa. +GTPS using an anti-R ac antibody and total _+ooP [ _]+GDP Cdc42 (b) using an anti-Cdc42
The Response of the Root Proteome to the Synthetic Strigolactone GR24 in Arabidopsis*

PubMed Central

Walton, Alan; Stes, Elisabeth; Goeminne, Geert; Braem, Lukas; Vuylsteke, Marnik; Matthys, Cedrick; De Cuyper, Carolien; Staes, An; Vandenbussche, Jonathan; Boyer, François-Didier; Vanholme, Ruben; Fromentin, Justine; Boerjan, Wout; Gevaert, Kris; Goormachtig, Sofie

2016-01-01

Strigolactones are plant metabolites that act as phytohormones and rhizosphere signals. Whereas most research on unraveling the action mechanisms of strigolactones is focused on plant shoots, we investigated proteome adaptation during strigolactone signaling in the roots of Arabidopsis thaliana. Through large-scale, time-resolved, and quantitative proteomics, the impact of the strigolactone analog rac-GR24 was elucidated on the root proteome of the wild type and the signaling mutant more axillary growth 2 (max2). Our study revealed a clear MAX2-dependent rac-GR24 response: an increase in abundance of enzymes involved in flavonol biosynthesis, which was reduced in the max2–1 mutant. Mass spectrometry-driven metabolite profiling and thin-layer chromatography experiments demonstrated that these changes in protein expression lead to the accumulation of specific flavonols. Moreover, quantitative RT-PCR revealed that the flavonol-related protein expression profile was caused by rac-GR24-induced changes in transcript levels of the corresponding genes. This induction of flavonol production was shown to be activated by the two pure enantiomers that together make up rac-GR24. Finally, our data provide much needed clues concerning the multiple roles played by MAX2 in the roots and a comprehensive view of the rac-GR24-induced response in the root proteome. PMID:27317401
Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krauthammer, Michael; Kong, Yong; Ha, Byung Hak

We characterized the mutational landscape of melanoma, the form of skin cancer with the highest mortality rate, by sequencing the exomes of 147 melanomas. Sun-exposed melanomas had markedly more ultraviolet (UV)-like C>T somatic mutations compared to sun-shielded acral, mucosal and uveal melanomas. Among the newly identified cancer genes was PPP6C, encoding a serine/threonine phosphatase, which harbored mutations that clustered in the active site in 12% of sun-exposed melanomas, exclusively in tumors with mutations in BRAF or NRAS. Notably, we identified a recurrent UV-signature, an activating mutation in RAC1 in 9.2% of sun-exposed melanomas. This activating mutation, the third most frequentmore » in our cohort of sun-exposed melanoma after those of BRAF and NRAS, changes Pro29 to serine (RAC1{sup P29S}) in the highly conserved switch I domain. Crystal structures, and biochemical and functional studies of RAC1{sup P29S} showed that the alteration releases the conformational restraint conferred by the conserved proline, causes an increased binding of the protein to downstream effectors, and promotes melanocyte proliferation and migration. These findings raise the possibility that pharmacological inhibition of downstream effectors of RAC1 signaling could be of therapeutic benefit.« less
Leader cells regulate collective cell migration via Rac activation in the downstream signaling of integrin β1 and PI3K

PubMed Central

Yamaguchi, Naoya; Mizutani, Takeomi; Kawabata, Kazushige; Haga, Hisashi

2015-01-01

Collective cell migration plays a crucial role in several biological processes, such as embryonic development, wound healing, and cancer metastasis. Here, we focused on collectively migrating Madin-Darby Canine Kidney (MDCK) epithelial cells that follow a leader cell on a collagen gel to clarify the mechanism of collective cell migration. First, we removed a leader cell from the migrating collective with a micromanipulator. This then caused disruption of the cohesive migration of cells that followed in movement, called “follower” cells, which showed the importance of leader cells. Next, we observed localization of active Rac, integrin β1, and PI3K. These molecules were clearly localized in the leading edge of leader cells, but not in follower cells. Live cell imaging using active Rac and active PI3K indicators was performed to elucidate the relationship between Rac, integrin β1, and PI3K. Finally, we demonstrated that the inhibition of these molecules resulted in the disruption of collective migration. Our findings not only demonstrated the significance of a leader cell in collective cell migration, but also showed that Rac, integrin β1, and PI3K are upregulated in leader cells and drive collective cell migration. PMID:25563751
Onset of the convection in a supercritical fluid.

PubMed

Meyer, H

2006-01-01

A model is proposed that leads to the scaled relation tp/tau D=Ftp(Ra-Rac) for the development of convection in a pure fluid in a Rayleigh-Bénard cell after the start of the heat current at t=0. Here tp is the time of the first maximum of the temperature drop DeltaT(t) across the fluid layer, the signature of rapidly growing convection, tau D is the diffusion relaxation time, and Rac is the critical Rayleigh number. Such a relation was first obtained empirically from experimental data. Because of the unknown perturbations in the cell that lead to convection development beyond the point of the fluid instability, the model determines tp/tau D within a multiplicative factor Psi square root Rac(HBL), the only fit parameter product. Here Rac(HBL), of the order 10(3), is the critical Rayleigh number of the hot boundary layer and Psi is a fit parameter. There is then good agreement over more than four decades of Ra-Rac between the model and the experiments on supercritical 3He at various heat currents and temperatures. The value of the parameter Psi, which phenomenologically represents the effectiveness of the perturbations, is discussed in connection with predictions by El Khouri and Carlès of the fluid instability onset time.
Polyomavirus and Naturally Occuring Neuroglial Tumors in Raccoons (Procyon Lotor).

PubMed

Pesavento, Patricia A; Brostoff, Terza; Church, Molly E; Dela Cruz, Florante N; Woolard, Kevin D

2016-01-01

Polyomavirus (PyV) infections are widespread in human populations and, although generally associated with silent persistence, rarely cause severe disease. Among diseases convincingly associated with natural PyV infections of humans, there are remarkably different tissue tropisms and outcomes, including progressive multifocal leukoencephalopathy, transient or progressive nephropathy, and cancer. The variable character and unpredictable outcomes of infection attest to large gaps in our basic understanding of PyV biology. In particular, the rich history of research demonstrating the oncogenic potential of PyVs in laboratory animals begs the question of why cancer is not more often associated with infection. Raccoon polyomavirus (RacPyV), discovered in 2010, is consistently identified in neuroglial tumors in free-ranging raccoons in the western United States. Exposure to RacPyV is widespread, and RacPyV is detected in tissues of raccoons without tumors. Studying the relationship of RacPyV with its natural host is a unique opportunity to uncover cogent cellular targets and protein interactions between the virus and its host. Our hypothesis is that RacPyV, as an intact episome, alters cellular pathways within neural progenitor cells and drives oncogenesis. © The Author 2016. Published by Oxford University Press on behalf of the Institute for Laboratory Animal Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Leader cells regulate collective cell migration via Rac activation in the downstream signaling of integrin β1 and PI3K.

PubMed

Yamaguchi, Naoya; Mizutani, Takeomi; Kawabata, Kazushige; Haga, Hisashi

2015-01-07

Collective cell migration plays a crucial role in several biological processes, such as embryonic development, wound healing, and cancer metastasis. Here, we focused on collectively migrating Madin-Darby Canine Kidney (MDCK) epithelial cells that follow a leader cell on a collagen gel to clarify the mechanism of collective cell migration. First, we removed a leader cell from the migrating collective with a micromanipulator. This then caused disruption of the cohesive migration of cells that followed in movement, called "follower" cells, which showed the importance of leader cells. Next, we observed localization of active Rac, integrin β1, and PI3K. These molecules were clearly localized in the leading edge of leader cells, but not in follower cells. Live cell imaging using active Rac and active PI3K indicators was performed to elucidate the relationship between Rac, integrin β1, and PI3K. Finally, we demonstrated that the inhibition of these molecules resulted in the disruption of collective migration. Our findings not only demonstrated the significance of a leader cell in collective cell migration, but also showed that Rac, integrin β1, and PI3K are upregulated in leader cells and drive collective cell migration.
Cirmtuzumab inhibits Wnt5a-induced Rac1 activation in chronic lymphocytic leukemia treated with ibrutinib

PubMed Central

Yu, J; Chen, L; Cui, B; Wu, Christina; Choi, M Y; Chen, Y; Zhang, L; Rassenti, L Z; Widhopf II, G F; Kipps, T J

2017-01-01

Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of ibrutinib, an inhibitor of Bruton's tyrosine kinase (BTK) that can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting alternative pathways also contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. In this study, we found that CLL cells of patients treated with ibrutinib had activated Rac1. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated with ibrutinib at concentrations that were effective in completely inhibiting BTK and BCR-signaling. Wnt5a-induced Rac1 activation could be blocked by cirmtuzumab (UC-961), an anti-ROR1 mAb. We found that treatment with cirmtuzumab and ibrutinib was significantly more effective than treatment with either agent alone in clearing leukemia cells in vivo. This study indicates that cirmtuzumab may enhance the activity of ibrutinib in the treatment of patients with CLL or other ROR1+ B-cell malignancies. PMID:27904138
Cirmtuzumab inhibits Wnt5a-induced Rac1 activation in chronic lymphocytic leukemia treated with ibrutinib.

PubMed

Yu, J; Chen, L; Cui, B; Wu, Christina; Choi, M Y; Chen, Y; Zhang, L; Rassenti, L Z; Widhopf Ii, G F; Kipps, T J

2017-06-01

Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of ibrutinib, an inhibitor of Bruton's tyrosine kinase (BTK) that can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting alternative pathways also contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. In this study, we found that CLL cells of patients treated with ibrutinib had activated Rac1. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated with ibrutinib at concentrations that were effective in completely inhibiting BTK and BCR-signaling. Wnt5a-induced Rac1 activation could be blocked by cirmtuzumab (UC-961), an anti-ROR1 mAb. We found that treatment with cirmtuzumab and ibrutinib was significantly more effective than treatment with either agent alone in clearing leukemia cells in vivo. This study indicates that cirmtuzumab may enhance the activity of ibrutinib in the treatment of patients with CLL or other ROR1 + B-cell malignancies.
78 FR 24381 - Southwest Idaho Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-25

... DEPARTMENT OF AGRICULTURE Forest Service Southwest Idaho Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Southwest Idaho Resource Advisory Committee (RAC) will meet in Boise, Idaho. The RAC is authorized under the Secure Rural Schools and Community...
75 FR 63853 - Notice of Intent To Reestablish and Call for Nominations for the Wyoming Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

... (FACA). The Bureau of Land Management (BLM) gives notice that the Secretary of the Interior is... the RAC. The RAC provides advice and recommendations on land use planning and management of the public...
The Role of Ect2 Nuclear RhoGEF Activity in Ovarian Cancer Cell Transformation

PubMed Central

Huff, Lauren P.; DeCristo, Molly J.; Trembath, Dimitri; Kuan, Pei Fen; Yim, Margaret; Liu, Jinsong; Cook, Danielle R.; Miller, C. Ryan; Der, Channing J.

2013-01-01

Ect2, a Rho guanine nucleotide exchange factor (RhoGEF), is atypical among RhoGEFs in its predominantly nuclear localization in interphase cells. One current model suggests that Ect2 mislocalization drives cellular transformation by promoting aberrant activation of cytoplasmic Rho family GTPase substrates. However, in ovarian cancers, where Ect2 is both amplified and overexpressed at the mRNA level, we observed that the protein is highly expressed and predominantly nuclear and that nuclear but not cytoplasmic Ect2 increases with advanced disease. Knockdown of Ect2 in ovarian cancer cell lines impaired their anchorage-independent growth without affecting their growth on plastic. Restoration of Ect2 expression rescued the anchorage-independent growth defect, but not if either the DH catalytic domain or the nuclear localization sequences of Ect2 were mutated. These results suggested a novel mechanism whereby Ect2 could drive transformation in ovarian cancer cells by acting as a RhoGEF specifically within the nucleus. Interestingly, Ect2 had an intrinsically distinct GTPase specificity profile in the nucleus versus the cytoplasm. Nuclear Ect2 bound preferentially to Rac1, while cytoplasmic Ect2 bound to RhoA but not Rac. Consistent with nuclear activation of endogenous Rac, Ect2 overexpression was sufficient to recruit Rac effectors to the nucleus, a process that required a functional Ect2 catalytic domain. Furthermore, expression of active nuclearly targeted Rac1 rescued the defect in transformed growth caused by Ect2 knockdown. Our work suggests a novel mechanism of Ect2-driven transformation, identifies subcellular localization as a regulator of GEF specificity, and implicates activation of nuclear Rac1 in cellular transformation. PMID:24386507
Three-color confocal Förster (or fluorescence) resonance energy transfer microscopy: Quantitative analysis of protein interactions in the nucleation of actin filaments in live cells.

PubMed

Wallrabe, Horst; Sun, Yuansheng; Fang, Xiaolan; Periasamy, Ammasi; Bloom, George S

2015-06-01

Experiments using live cell 3-color Förster (or fluorescence) resonance energy transfer (FRET) microscopy and corresponding in vitro biochemical reconstitution of the same proteins were conducted to evaluate actin filament nucleation. A novel application of 3-color FRET data is demonstrated, extending the analysis beyond the customary energy-transfer efficiency (E%) calculations. MDCK cells were transfected for coexpression of Teal-N-WASP/Venus-IQGAP1/mRFP1-Rac1, Teal-N-WASP/Venus-IQGAP1/mRFP1-Cdc42, CFP-Rac1/Venus-IQGAP1/mCherry-actin, or CFP-Cdc42/Venus-IQGAP1/mCherry-actin, and with single-label equivalents for spectral bleedthrough correction. Using confirmed E% as an entry point, fluorescence levels and related ratios were correlated at discrete accumulating levels at cell peripheries. Rising ratios of CFP-Rac1:Venus-IQGAP1 were correlated with lower overall actin fluorescence, whereas the CFP-Cdc42:Venus-IQGAP1 ratio correlated with increased actin fluorescence at low ratios, but was neutral at higher ratios. The new FRET analyses also indicated that rising levels of mRFP1-Cdc42 or mRFP1-Rac1, respectively, promoted or suppressed the association of Teal-N-WASP with Venus-IQGAP1. These 3-color FRET assays further support our in vitro results about the role of IQGAP1, Rac1, and Cdc42 in actin nucleation, and the differential impact of Rac1 and Cdc42 on the association of N-WASP with IQGAP1. In addition, this study emphasizes the power of 3-color FRET as a systems biology strategy for simultaneous evaluation of multiple interacting proteins in individual live cells. © 2015 International Society for Advancement of Cytometry.
RHOG-DOCK1-RAC1 Signaling Axis Is Perturbed in DHEA-Induced Polycystic Ovary in Rat Model.

PubMed

Ubba, Vaibhave; Soni, Upendra Kumar; Chadchan, Sangappa; Maurya, Vineet Kumar; Kumar, Vijay; Maurya, Ruchika; Chaturvedi, Himanshu; Singh, Rajender; Dwivedi, Anila; Jha, Rajesh Kumar

2017-05-01

The function of RHOG, a RAC1 activator, was explored in the ovary during ovarian follicular development and pathological conditions. With the help of immunoblotting and immunolocalization, we determined the expression and localization of RHOG in normal (estrous cycle) and polycystic ovaries using Sprague Dawley (SD) rat model. Employing polymerase chain reaction and flow cytometry, we analyzed the transcript and expression levels of downstream molecules of RHOG, DOCK1, and RAC1 in the polycystic ovarian syndrome (PCOS) ovary along with normal antral follicular theca and granulosa cells after dehydroepiandrosterone (DHEA) supplementation. The effect of RHOG knockdown on DOCK1, VAV, and RAC1 expression was evaluated in the human ovarian cells (SKOV3), theca cells, and granulosa cells from SD rats with the help of flow cytometry. Oocyte at secondary follicles along with stromal cells showed optimal expression of RHOG. Immunoblotting of RHOG revealed its maximum expression at diestrus and proestrus, which was downregulated at estrus stage. Mild immunostaining of RHOG was also present in the theca and granulosa cells of the secondary and antral follicles. Polycystic ovary exhibited weak immunostaining for RHOG and that was corroborated by immunoblotting-based investigations. RHOG effectors DOCK1 and ELMO1 were found reduced in the ovary in PCOS condition/DHEA. RHOG silencing reduced the expression of DOCK1 and RAC1 in the theca and granulosa cells from SD rat antral follicles and that was mirrored in the human ovarian cells. Collectively, RHOG can mediate signaling through downstream effectors DOCK1 and RAC1 during ovarian follicular development (theca and granulosa cells and oocyte), but DHEA downregulated them in the PCOS ovary.
Optogenetics to target actin-mediated synaptic loss in Alzheimer's

NASA Astrophysics Data System (ADS)

Zahedi, Atena; DeFea, Kathryn; Ethell, Iryna

2013-03-01

Numerous studies in Alzheimer's Disease (AD) animal models show that overproduction of Aβ peptides and their oligomerization can distort dendrites, damage synapses, and decrease the number of dendritic spines and synapses. Aβ may trigger synapse loss by modulating activity of actin-regulating proteins, such as Rac1 and cofilin. Indeed, Aβ1-42 oligomers can activate actin severing protein cofilin through calcineurin-mediated activation of phosphatase slingshot and inhibit an opposing pathway that suppresses cofilin phosphorylation through Rac-mediated activation of LIMK1. Excessive activation of actin-severing protein cofilin triggers the formation of a non-dynamic actin bundles, called rods that are found in AD brains and cause loss of synapses. Hence, regulation of these actin-regulating proteins in dendritic spines could potentially provide useful tools for preventing the synapse/spine loss associated with earlier stages of AD neuropathology. However, lack of spatiotemporal control over their activity is a key limitation. Recently, optogenetic advancements have provided researchers with convenient light-activating proteins such as photoactivatable Rac (PARac). Here, we transfected cultured primary hippocampal neurons and human embryonic kidney (HEK) cells with a PARac/ mCherry-containing plasmid and the mCherry-positive cells were identified and imaged using an inverted fluorescence microscope. Rac1 activation was achieved by irradiation with blue light (480nm) and live changes in dendritic spine morphology were observed using mCherry (587nm). Rac activation was confirmed by immunostaining for phosphorylated form of effector proteinP21 protein-activated kinase 1 (PAK1) and reorganization of actin. Thus, our studies confirm the feasibility of using the PA-Rac construct to trigger actin re-organization in the dendritic spines.
Effects of the GABAB Receptor-Positive Modulators CGP7930 and rac-BHFF in Baclofen- and γ-Hydroxybutyrate-Discriminating Pigeons

PubMed Central

France, Charles P.; Cheng, Kejun; Rice, Kenner C.

2012-01-01

In vivo effects of GABAB receptor-positive modulators suggest them to have therapeutic potential to treat central nervous system disorders such as anxiety and drug abuse. Although these effects are thought to be mediated by positive modulation of GABAB receptors, such modulation has been examined primarily in vitro. This study further examined the in vivo properties of the GABAB receptor-positive modulators 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl) phenol (CGP7930) and (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF). In pigeons discriminating baclofen from saline, γ-hydroxybutyrate (GHB) produced 100% baclofen-appropriate responding, and the GABAB antagonist 3-aminopropyl(dimethoxymethyl) phosphinic acid (CGP35348) blocked the effects of both drugs. CGP7930 and rac-BHFF produced at most 41 and 74% baclofen-appropriate responding, respectively, and enhanced the discriminative stimulus effects of baclofen, but not of GHB. In pigeons discriminating GHB from saline, CGP7930 and rac-BHFF produced at most 1 and 49% GHB-appropriate responding, respectively, and enhanced the effects of baclofen, but not of GHB. Enhancement of the discriminative stimulus effects of baclofen by rac-BHFF and CGP7930 is further evidence of their effectiveness as GABAB receptor-positive modulators in vivo. Furthermore, lack of complete substitution of the positive modulators rac-BHFF and CGP7930 for baclofen and GHB suggests that their discriminative stimulus effects differ from those of GABAB receptor agonists. Finally, together with converging evidence that the GABAB receptor populations mediating the effects of baclofen and GHB are not identical, the present findings suggest that these populations differ in their susceptibility to positive modulatory effects. Such differences could allow for more selective therapeutic targeting of the GABAB system. PMID:22319197
Comparison of vonoprazan and proton pump inhibitors for eradication of Helicobacter pylori.

PubMed

Shinozaki, Satoshi; Nomoto, Hiroaki; Kondo, Yoshie; Sakamoto, Hirotsugu; Hayashi, Yoshikazu; Yamamoto, Hironori; Lefor, Alan Kawarai; Osawa, Hiroyuki

2016-05-01

Alternative eradication therapies for Helicobacter pylori infection are needed because of an increasing failure rate over the past decade. The aim of this study was to determine if vonoprazan, a new potassium-competitive acid blocker, showed superiority to existing proton pump inhibitors for primary eradication of H. pylori in routine clinical practice. Data for 573 patients who underwent primary H. pylori eradication therapy were retrospectively reviewed. Regimens included clarithromycin 200 mg, amoxicillin 750 mg, and an acid-suppressing drug [lansoprazole 30 mg (LAC), rabeprazole 10 mg (RAC), esomeprazole 20 mg (EAC), or vonoprazan 20 mg (VAC)] twice daily for 1 week. Eradication was successful in 73% (419/573) of patients using intention-to-treat (ITT) analysis and 76% (419/549) of patients in per-protocol (PP) analysis. The VAC group had a significantly superior eradication rate compared with the LAC and RAC groups in ITT (VAC 83%, LAC 66% and RAC 67%, p < 0.01) and PP analysis (VAC 85%, LAC 69% and RAC 70%, p < 0.01), and had a similarly high eradication rate to the EAC group (83% in ITT and 87% in PP). Although the eradication rate in the VAC and EAC groups was not significantly higher than in the LAC and RAC groups in patients with mild gastric atrophy with both ITT and PP analyses, it was significantly higher in patients with severe gastric atrophy (p < 0.01). The VAC group had a significantly higher H. pylori eradication rate than the LAC and RAC groups, and a > 80% eradication rate regardless of the degree of atrophy. Copyright © 2016. Published by Elsevier Taiwan.
Impacts of Rac- and S-metolachlor on cyanobacterial cell integrity and release of microcystins at different nitrogen levels.

PubMed

Wang, Jia; Zhang, Lijuan; Fan, Jiajia; Wen, Yuezhong

2017-08-01

Pesticide residues and nitrogen overload (which caused cyanobacteria blooms) have been two serious environmental concerns. In particular, chiral pesticides with different structures may have various impacts on cyanobacteria. Nitrogen may affect the behavior between pesticides and cyanobacteria (e.g., increase the adverse effects of pesticides on cyanobacteria). This study evaluated the impacts of Rac- and S-metolachlor on the cell integrity and toxin release of Microcystis aeruginosa cells at different nitrogen levels. The results showed that (both of the configurations: Rac-, S-) metolachlor could inhibit M. aeruginosa cell growth under most conditions, and the inhibition rates were increased with the growing concentrations of nitrogen and metolachlor. However, cyanobacterial growth was promoted in 48 h under environmental relevant condition (1 mg/L metolachlor and 0.15 mg/L nitrogen). Therefore, the water authorities should adjust the treatment parameters to remove possible larger numbers of cyaonbacteria under that condition. On the other hand, the inhibition degree of M. aeruginosa cell growth by S-metolachlor treatments was obviously larger than Rac-metolachlor treatments. S-metolachlor also had a stronger ability in compromising M. aeruginosa cells than Rac-metolachlor treatments. Compared to control samples, more extracellular toxins (12%-86% increases) were detected after 5 mg/L S-metolachlor treatment for 72 h at different nitrogen levels, but the variations of extracellular toxins caused by 5 mg/L Rac-metolachlor addition could be neglected. Consequently, higher concentrations of metolachlor in source waters are harmful to humans, but it may prevent cyanobacterial blooms. However, the potential risks (e.g. build-up of extracellular toxins) should be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.
Structural insights into the interaction of IL-33 with its receptors.

PubMed

Liu, Xi; Hammel, Michal; He, Yanfeng; Tainer, John A; Jeng, U-Ser; Zhang, Linqi; Wang, Shuying; Wang, Xinquan

2013-09-10

Interleukin (IL)-33 is an important member of the IL-1 family that has pleiotropic activities in innate and adaptive immune responses in host defense and disease. It signals through its ligand-binding primary receptor ST2 and IL-1 receptor accessory protein (IL-1RAcP), both of which are members of the IL-1 receptor family. To clarify the interaction of IL-33 with its receptors, we determined the crystal structure of IL-33 in complex with the ectodomain of ST2 at a resolution of 3.27 Å. Coupled with structure-based mutagenesis and binding assay, the structural results define the molecular mechanism by which ST2 specifically recognizes IL-33. Structural comparison with other ligand-receptor complexes in the IL-1 family indicates that surface-charge complementarity is critical in determining ligand-binding specificity of IL-1 primary receptors. Combined crystallography and small-angle X-ray-scattering studies reveal that ST2 possesses hinge flexibility between the D3 domain and D1D2 module, whereas IL-1RAcP exhibits a rigid conformation in the unbound state in solution. The molecular flexibility of ST2 provides structural insights into domain-level conformational change of IL-1 primary receptors upon ligand binding, and the rigidity of IL-1RAcP explains its inability to bind ligands directly. The solution architecture of IL-33-ST2-IL-1RAcP complex from small-angle X-ray-scattering analysis resembles IL-1β-IL-1RII-IL-1RAcP and IL-1β-IL-1RI-IL-1RAcP crystal structures. The collective results confer IL-33 structure-function relationships, supporting and extending a general model for ligand-receptor assembly and activation in the IL-1 family.
CT-Guided Microwave Ablation of 45 Renal Tumors: Analysis of Procedure Complexity Utilizing a Percutaneous Renal Ablation Complexity Scoring System.

PubMed

Mansilla, Alberto V; Bivins, Eugene E; Contreras, Francisco; Hernandez, Manuel A; Kohler, Nathan; Pepe, Julie W

2017-02-01

To develop a scoring system that stratifies complexity of percutaneous ablation of renal tumors. Analysis was performed of 36 consecutive patients (mean age, 64 y; range, 30-89 y) who underwent CT-guided microwave (MW) ablation of 45 renal tumors (mean tumor diameter, 2.4 cm; range, 1.2-4.0 cm). Technical success and effectiveness were determined based on intraprocedural and follow-up imaging studies. The RENAL score and the proposed percutaneous renal ablation complexity (P-RAC) score were calculated for each tumor. Technical success was 93.3% (n = 42). Biopsy of 38 of 45 renal tumors revealed 23 renal cell carcinomas. Median follow-up period was 9.7 months (range, 2.9-46.8 months). There were no tumor recurrences. One major complication, ureteropelvic junction stricture, occurred (2.6%). The P-RAC score was found to differ statistically from the RENAL score (t = 3.754, df = 44, P = .001). A positive correlation was found between the P-RAC score and number of antenna insertions (r = .378, n = 45, P = .011) and procedure duration (r = .328, n = 45, P = .028). No correlation was found between the RENAL score and number of MW antenna insertions (r = .110, n = 45, P = .472) or procedure duration (r = .263, n = 45, P = .081). Hydrodissection was significantly more common in the P-RAC high-complexity category than in low-complexity category (χ 2 = 12.073, df = 2, P = .002). The P-RAC score may be useful in stratifying percutaneous renal ablation complexity. Further studies with larger sample sizes are necessary to validate the P-RAC score and to determine if it can predict risk of complications. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.
Suppressing the formation of lipid raft-associated Rac1/PI3K/Akt signaling complexes by curcumin inhibits SDF-1α-induced invasion of human esophageal carcinoma cells.

PubMed

Lin, Meng-Liang; Lu, Yao-Cheng; Chen, Hung-Yi; Lee, Chuan-Chun; Chung, Jing-Gung; Chen, Shih-Shun

2014-05-01

Stromal cell-derived factor-1α (SDF-1α) is a ligand for C-X-C chemokine receptor type 4 (CXCR4), which contributes to the metastasis of cancer cells by promoting cell migration. Here, we show that the SDF-1α/CXCR4 axis can significantly increase invasion of esophageal carcinoma (EC) cells. We accomplished this by examining the effects of CXCR4 knockdown as well as treatment with a CXCR4-neutralizing antibody and the CXCR4-specific inhibitor AMD3100. Curcumin suppressed SDF-1α-induced cell invasion and matrix metalloproteinase-2 (MMP-2) promoter activity, cell surface localization of CXCR4 at lipid rafts, and lipid raft-associated ras-related C3 botulinum toxin substrate 1 (Rac1)/phosphatidylinositol 3-kinase (PI3K) p85α/Akt signaling. Curcumin inhibited SDF-1α-induced cell invasion by suppressing the Rac1-PI3K signaling complex at lipid rafts but did not abrogate lipid raft formation. We further demonstrate that the attenuation of lipid raft-associated Rac1 activity by curcumin was critical for the inhibition of SDF-1α-induced PI3K/Akt/NF-κB activation, cell surface localization of CXCR4 at lipid rafts, MMP-2 promoter activity, and cell invasion. Collectively, our results indicate that curcumin inhibits SDF-1α-induced EC cell invasion by suppressing the formation of the lipid raft-associated Rac1-PI3K-Akt signaling complex, the localization of CXCR4 with lipid rafts at the cell surface, and MMP-2 promoter activity, likely through the inhibition of Rac1 activity. © 2012 Wiley Periodicals, Inc.
Role of Abl kinase and the Wave2 signaling complex in HIV-1 entry at a post-hemifusion step.

PubMed

Harmon, Brooke; Campbell, Nancy; Ratner, Lee

2010-06-17

Entry of human immunodeficiency virus type 1 (HIV-1) commences with binding of the envelope glycoprotein (Env) to the receptor CD4, and one of two coreceptors, CXCR4 or CCR5. Env-mediated signaling through coreceptor results in Galphaq-mediated Rac activation and actin cytoskeleton rearrangements necessary for fusion. Guanine nucleotide exchange factors (GEFs) activate Rac and regulate its downstream protein effectors. In this study we show that Env-induced Rac activation is mediated by the Rac GEF Tiam-1, which associates with the adaptor protein IRSp53 to link Rac to the Wave2 complex. Rac and the tyrosine kinase Abl then activate the Wave2 complex and promote Arp2/3-dependent actin polymerization. Env-mediated cell-cell fusion, virus-cell fusion and HIV-1 infection are dependent on Tiam-1, Abl, IRSp53, Wave2, and Arp3 as shown by attenuation of fusion and infection in cells expressing siRNA targeted to these signaling components. HIV-1 Env-dependent cell-cell fusion, virus-cell fusion and infection were also inhibited by Abl kinase inhibitors, imatinib, nilotinib, and dasatinib. Treatment of cells with Abl kinase inhibitors did not affect cell viability or surface expression of CD4 and CCR5. Similar results with inhibitors and siRNAs were obtained when Env-dependent cell-cell fusion, virus-cell fusion or infection was measured, and when cell lines or primary cells were the target. Using membrane curving agents and fluorescence microscopy, we showed that inhibition of Abl kinase activity arrests fusion at the hemifusion (lipid mixing) step, suggesting a role for Abl-mediated actin remodeling in pore formation and expansion. These results suggest a potential utility of Abl kinase inhibitors to treat HIV-1 infected patients.
76 FR 39893 - Notice of Public Meeting, New Mexico Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-07

..., Roswell, NM 88201, from 10 a.m.-4 p.m. The public may send written comments to the RAC at the above.... 2nd Street, Roswell, NM 88201, 575-627-0242. SUPPLEMENTARY INFORMATION: The 10-member RAC advises the...
78 FR 23741 - North Central Idaho Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-22

... DEPARTMENT OF AGRICULTURE Forest Service North Central Idaho Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The North Central Idaho Resource Advisorsy Committee (RAC) will be meet in Grangeville, Idaho. The RAC is authorized under the Secure Rural Schools and...
78 FR 49446 - Lyon-Mineral County Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-14

... DEPARTMENT OF AGRICULTURE Forest Service Lyon-Mineral County Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meetings. SUMMARY: The Lyon-Mineral County Resource Advisory Committee (RAC) will meet in Yerrington, Nevada. The RAC is meeting as authorized under the Secure Rural...
Fanca−/− hematopoietic stem cells demonstrate a mobilization defect which can be overcome by administration of the Rac inhibitor NSC23766

PubMed Central

Milsom, Michael D.; Lee, Andrew W.; Zheng, Yi; Cancelas, Jose A.

2009-01-01

Fanconi anemia is a severe bone marrow failure syndrome resulting from inactivating mutations of Fanconi anemia pathway genes. Gene and cell therapy trials using hematopoietic stem cells and progenitors have been hampered by poor mobilization of HSC to peripheral blood in response to G-CSF. Using a murine model of Fanconi anemia (Fanca−/− mice), we found that the Fanca deficiency was associated with a profound defect in hematopoietic stem cells and progenitors mobilization in response to G-CSF in absence of bone marrow failure, which correlates with the findings of clinical trials in Fanconi anemia patients. This mobilization defect was overcome by co-administration of the Rac inhibitor NSC23766, suggesting that Rac signaling is implicated in the retention of Fanca−/− hematopoietic stem cells and progenitors in the bone marrow. In view of these data, we propose that targeting Rac signaling may enhance G-CSF-induced HSC mobilization in Fanconi anemia. PMID:19491337

Fanca-/- hematopoietic stem cells demonstrate a mobilization defect which can be overcome by administration of the Rac inhibitor NSC23766.

PubMed

Milsom, Michael D; Lee, Andrew W; Zheng, Yi; Cancelas, Jose A

2009-07-01

Fanconi anemia is a severe bone marrow failure syndrome resulting from inactivating mutations of Fanconi anemia pathway genes. Gene and cell therapy trials using hematopoietic stem cells and progenitors have been hampered by poor mobilization of HSC to peripheral blood in response to G-CSF. Using a murine model of Fanconi anemia (Fanca(-/-) mice), we found that the Fanca deficiency was associated with a profound defect in hematopoietic stem cells and progenitors mobilization in response to G-CSF in absence of bone marrow failure, which correlates with the findings of clinical trials in Fanconi anemia patients. This mobilization defect was overcome by co-administration of the Rac inhibitor NSC23766, suggesting that Rac signaling is implicated in the retention of Fanca(-/-) hematopoietic stem cells and progenitors in the bone marrow. In view of these data, we propose that targeting Rac signaling may enhance G-CSF-induced HSC mobilization in Fanconi anemia.
Colorectal cancer chemoprevention: the potential of a selective approach.

PubMed

Ben-Amotz, Oded; Arber, Nadir; Kraus, Sarah

2010-10-01

Colorectal cancer (CRC) is a leading cause of cancer death, and therefore demands special attention. Novel recent approaches for the chemoprevention of CRC focus on selective targeting of key pathways. We review the study by Zhang and colleagues, evaluating a selective approach targeting APC-deficient premalignant cells using retinoid-based therapy and TNF-related apoptosis-inducing ligand (TRAIL). This study demonstrates that induction of TRAIL-mediated death signaling contributes to the chemopreventive value of all-trans-retinyl acetate (RAc) by sensitizing premalignant adenoma cells for apoptosis without affecting normal cells. We discuss these important findings, raise few points that deserve consideration, and may further contribute to the development of RAc-based combination therapies with improved efficacy. The authors clearly demonstrate a synergistic interaction between TRAIL, RAc and APC, which leads to the specific cell death of premalignant target cells. The study adds to the growing body of literature related to CRC chemoprevention, and provides solid data supporting a potentially selective approach for preventing CRC using RAc and TRAIL.
Evidences that beta1 integrin and Rac1 are involved in the overriding effect of laminin on myelin-associated glycoprotein inhibitory activity on neuronal cells.

PubMed

Laforest, Sullivan; Milanini, Julie; Parat, Fabrice; Thimonier, Jean; Lehmann, Maxime

2005-11-01

During neurite elongation, migrating growth cones encounter both permissive and inhibitory substrates, such as laminin and MAG (myelin-associated glycoprotein), respectively. Here, we demonstrated on two neuronal cell lines (PC12 and N1E-115), that laminin and collagen hampered, in a dose-dependent manner, MAG inhibitory activity on several integrin functions, i.e., neurite growth, cell adhesion and cell spreading. Using a function blocking antibody, in PC12 cells, we showed that alpha1beta1 integrin is required in these phenomena. In parallel, we observed that MAG perturbs actin dynamics and lamellipodia formation during early steps of cell spreading. This seemed to be independent of RhoA activation, but dependent of Rac-1 inhibition by MAG. Laminin overrode MAG activity on actin and prevented MAG inhibition NGF-induced Rac1 activation. In conclusion, we evidenced antagonistic signaling between MAG receptors and beta1 integrins, in which Rac-1 may have a central function.
Tiam1 interaction with the PAR complex promotes talin-mediated Rac1 activation during polarized cell migration

PubMed Central

Wang, Shujie; Watanabe, Takashi; Matsuzawa, Kenji; Katsumi, Akira; Kakeno, Mai; Matsui, Toshinori; Ye, Feng; Sato, Kazuhide; Murase, Kiyoko; Sugiyama, Ikuko; Kimura, Kazushi; Mizoguchi, Akira; Ginsberg, Mark H.; Collard, John G.

2012-01-01

Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration. PMID:23071154
Determination of ractopamine in pork using a magnetic molecularly imprinted polymer as adsorbent followed by HPLC.

PubMed

Tang, Yiwei; Gao, Jingwen; Liu, Xiuying; Lan, Jianxing; Gao, Xue; Ma, Yong; Li, Min; Li, Jianrong

2016-06-15

A new magnetic molecularly imprinted polymers (MMIPs) for separation and concentration of ractopamine (RAC) were prepared using surface molecular imprinting technique with methacryloyl chloride as functional monomer and RAC as template. The MMIPs were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometer. The results of re-binding experiments indicated that the MMIPs had fast adsorption kinetics and could reach binding equilibrium within 20 min, and the adsorption capacity of the MMIPs was 2.87-fold higher than that of the corresponding non-imprinted polymer. The selectivity of the MMIPs was evaluated according to its recognition to RAC and its analogues. The synthesized MMIPs were successfully applied to extraction, followed by high performance liquid chromatography to determine RAC in real food samples. Spiked recoveries ranged from 73.60% to 94.5%, with relative standard deviations of <11.17%. Copyright © 2016 Elsevier Ltd. All rights reserved.
Reclamation chain of waste concrete: A case study of Shanghai.

PubMed

Xiao, Jianzhuang; Ma, Zhiming; Ding, Tao

2016-02-01

A mass of construction and demolition (C&D) waste are generated in Shanghai every year, and it has become a serious environment problem. Reclaiming the waste concrete to produce recycled aggregate (RA) and recycled aggregate concrete (RAC) is an effective method to reduce the C&D waste. This paper develops a reclamation chain of waste concrete based on the researches and practices in Shanghai. C&D waste management, waste concrete disposition, RA production and RAC preparation are discussed respectively. In addition, technical suggestions are also given according to the findings in practical engineering, which aims to optimize the reclamation chain. The results show that the properties of RA and RAC can well meet the requirement of design and practical application through a series of technical measures. The reclamation chain of waste concrete is necessary and appropriate for Shanghai, which provides more opportunities for the wider application of RA and RAC, and it shows a favorable environmental benefit. Copyright © 2015 Elsevier Ltd. All rights reserved.
Sonic hedgehog signaling regulates actin cytoskeleton via Tiam1-Rac1 cascade during spine formation.

PubMed

Sasaki, Nobunari; Kurisu, Junko; Kengaku, Mineko

2010-12-01

The sonic hedgehog (Shh) pathway has essential roles in several processes during development of the vertebrate central nervous system (CNS). Here, we report that Shh regulates dendritic spine formation in hippocampal pyramidal neurons via a novel pathway that directly regulates the actin cytoskeleton. Shh signaling molecules Patched (Ptc) and Smoothened (Smo) are expressed in several types of postmitotic neurons, including cerebellar Purkinje cells and hippocampal pyramidal neurons. Knockdown of Smo induces dendritic spine formation in cultured hippocampal neurons independently of Gli-mediated transcriptional activity. Smo interacts with Tiam1, a guanine nucleotide exchange factor for Rac1, via its cytoplasmic C-terminal region. Inhibition of Tiam1 or Rac1 activity suppresses spine induction by Smo knockdown. Shh induces remodeling of the actin cytoskeleton independently of transcriptional activation in mouse embryonic fibroblasts. These findings demonstrate a novel Shh pathway that regulates the actin cytoskeleton via Tiam1-Rac1 activation. Copyright © 2010 Elsevier Inc. All rights reserved.
ArhGAP15, a Rac-specific GTPase-activating Protein, Plays a Dual Role in Inhibiting Small GTPase Signaling*

PubMed Central

Radu, Maria; Rawat, Sonali J.; Beeser, Alexander; Iliuk, Anton; Tao, Weiguo Andy; Chernoff, Jonathan

2013-01-01

Signaling from small GTPases is a tightly regulated process. In this work we used a protein microarray screen to identify the Rac-specific GAP, ArhGAP15, as a substrate of the Rac effectors Pak1 and Pak2. In addition to serving as a substrate of Pak1/2, we found that ArhGAP15, via its PH domain, bound to these kinases. The association of ArhGAP15 to Pak1/2 resulted in mutual inhibition of GAP and kinase catalytic activity, respectively. Knock-down of ArhGAP15 resulted in activation of Pak1/2, both indirectly, as a result of Rac activation, and directly, as a result of disruption of the ArhGAP15/Pak complex. Our data suggest that ArhGAP15 plays a dual negative role in regulating small GTPase signaling, by acting at the level of the GTPase itself, as well interacting with its effector, Pak kinase. PMID:23760270
Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3 and KIT driven Leukemogenesis

PubMed Central

Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Mali, Raghuveer Singh; Martin, Holly; Kobayashi, Michihiro; Vemula, Sasidhar; Canela, Victor H.; Waskow, Emily R.; Visconte, Valeria; Tiu, Ramon V.; Smith, Catherine C.; Shah, Neil; Bunting, Kevin D.; Boswell, H. Scott; Liu, Yan; Chan, Rebecca J.; Kapur, Reuben

2015-01-01

SUMMARY Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPN) and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK), whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis. PMID:25456130
Speciation of heavy metals Cu, Ni and Zn by modified BCR sequential extraction procedure in sediments from Banten Bay, Banten Province, Indonesia

NASA Astrophysics Data System (ADS)

Lestari; Budiyanto, F.; Hindarti, D.

2018-02-01

Banten Bay is categorized as a marine area that is busy with marine tourism activities, settlements and also industries. One potential impact of the condition is the occurrence of pollution from both industrial and domestic sources, erosion and sedimentation in the coastal environment. Samples were collected from 25 representative stations in April 2016. Chemical speciation of three heavy metals (Cu, Ni, and Zn) was studied using a modified sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM&T) program, formerly the Community Bureau of Reference (BCR). The aims of this study are to determine geochemical speciation of 4 bounds of metal: acid-soluble, reducible, oxidizable and residual, and to assess their impacts in the sediments of Banten Bay, Indonesia. The result shows that the percentage of Copper (45.90-83.75%), Nickel (18.28-65.66%), and Zinc (30.45-79.51%) were mostly accumulated in residual fraction of the total concentrations. The Risk Assessment Code (RAC) reveals that about 0-7.07% of Copper and 1.11-24.35 % of Zinc at sites exist in exchangeable fraction and therefore, they are in low risk category. While 7.34-34.90 of Ni at sites exists in exchangeable fraction and therefore, it is in medium risk category to aquatic environment.
Imaging human intrasynaptic dopamine release by IV cocaine and amphetamine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, D.F.; Hong, C.; Yokoi, F.

1995-05-01

Intrasynaptic dopamine (DA) release was measured with C-11 Raclopride (RAC) PET in 15 human subjects with two psychostimulant drugs, IV cocaine or IV amphetamine (AMPH). Eleven cocaine users received IV saline then cocaine with high specific activity (SA) tracer RAC by IV bolus. To determine the optimal timing of drug administration, subjects received 48mg cocaine at 0 min.(1 subject), 4 min.(3 subjects) or 10 min.(7 subjects) post injection (mpi). One received 32mg at 4 and 16mg at 10 mpi. In a separate paradigm, the effect of AMPH not only on the binding of Hi SA but also on the receptormore » density (B{sub max}) using Hi SA and low SA was examined. Four normals received 2 pairs of Hi SA and Low SA RAC PET scans, each pair separated by 1 week to estimate 2 B{sub max}`s, one affected by AMPH. Before the 2nd pair, 0.3mg/kg IV AMPH was given in the times corresponding to the AMPH times for the 1s B{sub max} measurement. All were scanned on a GE 4096WB+PET with 50 frames over 90 min with radial arterial plasma sampling and HPLC metabolite correction. Neuropsychological-endocrine testing was done concurrently. All subjects had a marked psychophysiological response for cocaine or AMPH (less with Low SA RAC). However, evidence of substantial DA release was not consistent with IV cocaine nor correlated with any timing of cocaine vs. RAC, except for an overall trend for RAC reduction with cocaine. The % change in k{sub 3}/k{sub 4} by graphical analysis ranged from +10 to -21%, with similar changes by other methods of quantification, such as k{sub 3}/k{sub 4} constrained to cerebellar K{sub 1}/k{sub 2}, and simple tissue ratios comparisons. IV AMPH showed DA release (19% {plus_minus} 2 (SEM) decrease) in all Hi SA RAC (k{sub 3}/k{sub 4}) by graphical analysis. The calculation of B{sub max} in putamen using Scatchard analysis (baseline B{sub max}29{plus_minus}2) showed 12 to 28% decreases following AMPH.« less
Phosphatidylinositol 3-kinase, Cdc42, and Rac1 act downstream of Ras in integrin-dependent neurite outgrowth in N1E-115 neuroblastoma cells.

PubMed

Sarner, S; Kozma, R; Ahmed, S; Lim, L

2000-01-01

Ras and Rho family GTPases have been ascribed important roles in signalling pathways determining cellular morphology and growth. Here we investigated the roles of the GTPases Ras, Cdc42, Rac1, and Rho and that of phosphatidylinositol 3-kinase (PI 3-kinase) in the pathway leading from serum starvation to neurite outgrowth in N1E-115 neuroblastoma cells. Serum-starved cells grown on a laminin matrix exhibited integrin-dependent neurite outgrowth. Expression of dominant negative mutants of Ras, PI 3-kinase, Cdc42, or Rac1 all blocked this neurite outgrowth, while constitutively activated mutants of Ras, PI 3-kinase, or Cdc42 were each sufficient to promote outgrowth even in the presence of serum. A Ras(H40C;G12V) double mutant which binds preferentially to PI 3-kinase also promoted neurite formation. Activated Ras(G12V)-induced outgrowth required PI 3-kinase activity, but activated PI 3-kinase-induced outgrowth did not require Ras activity. Although activated Rac1 by itself did not induce neurites, neurite outgrowth induced by activated Cdc42(G12V) was Rac1 dependent. Cdc42(G12V)-induced neurites appeared to lose their normal polarization, almost doubling the average number of neurites produced by a single cell. Outgrowth induced by activated Ras or PI 3-kinase required both Cdc42 and Rac1 activity, but Cdc42(G12V)-induced outgrowth did not need Ras or PI 3-kinase activity. Active Rho(G14V) reduced outgrowth promoted by Ras(G12V). Finally, expression of dominant negative Jun N-terminal kinase or extracellular signal-regulated kinase did not inhibit outgrowth, suggesting these pathways are not essential for this process. Our results suggest a hierarchy of signalling where Ras signals through PI 3-kinase to Cdc42 and Rac1 activation (and Rho inactivation), culminating in neurite outgrowth. Thus, in the absence of serum factors, Ras may initiate cell cycle arrest and terminal differentiation in N1E-115 neuroblastoma cells.
Phosphatidylinositol 3-Kinase, Cdc42, and Rac1 Act Downstream of Ras in Integrin-Dependent Neurite Outgrowth in N1E-115 Neuroblastoma Cells

PubMed Central

Sarner, Shula; Kozma, Robert; Ahmed, Sohail; Lim, Louis

2000-01-01

Ras and Rho family GTPases have been ascribed important roles in signalling pathways determining cellular morphology and growth. Here we investigated the roles of the GTPases Ras, Cdc42, Rac1, and Rho and that of phosphatidylinositol 3-kinase (PI 3-kinase) in the pathway leading from serum starvation to neurite outgrowth in N1E-115 neuroblastoma cells. Serum-starved cells grown on a laminin matrix exhibited integrin-dependent neurite outgrowth. Expression of dominant negative mutants of Ras, PI 3-kinase, Cdc42, or Rac1 all blocked this neurite outgrowth, while constitutively activated mutants of Ras, PI 3-kinase, or Cdc42 were each sufficient to promote outgrowth even in the presence of serum. A RasH40C;G12V double mutant which binds preferentially to PI 3-kinase also promoted neurite formation. Activated RasG12V-induced outgrowth required PI 3-kinase activity, but activated PI 3-kinase-induced outgrowth did not require Ras activity. Although activated Rac1 by itself did not induce neurites, neurite outgrowth induced by activated Cdc42G12V was Rac1 dependent. Cdc42G12V-induced neurites appeared to lose their normal polarization, almost doubling the average number of neurites produced by a single cell. Outgrowth induced by activated Ras or PI 3-kinase required both Cdc42 and Rac1 activity, but Cdc42G12V-induced outgrowth did not need Ras or PI 3-kinase activity. Active RhoG14V reduced outgrowth promoted by RasG12V. Finally, expression of dominant negative Jun N-terminal kinase or extracellular signal-regulated kinase did not inhibit outgrowth, suggesting these pathways are not essential for this process. Our results suggest a hierarchy of signalling where Ras signals through PI 3-kinase to Cdc42 and Rac1 activation (and Rho inactivation), culminating in neurite outgrowth. Thus, in the absence of serum factors, Ras may initiate cell cycle arrest and terminal differentiation in N1E-115 neuroblastoma cells. PMID:10594018
Identification of a RAC/AKT-like gene in Leishmania parasites as a putative therapeutic target in leishmaniasis.

PubMed

Varela-M, Rubén E; Ochoa, Rodrigo; Muskus, Carlos E; Muro, Antonio; Mollinedo, Faustino

2017-10-10

Leishmaniasis is one of the world's most neglected diseases caused by at least 20 different species of the protozoan parasite Leishmania. Although new drugs have become recently available, current therapy for leishmaniasis is still unsatisfactory. A subgroup of serine/threonine protein kinases named as related to A and C protein kinases (RAC), or protein kinase B (PKB)/AKT, has been identified in several organisms including Trypanosoma cruzi parasites. PKB/AKT plays a critical role in mammalian cell signaling promoting cell survival and is a major drug target in cancer therapy. However, the role of protozoan parasitic PKB/AKT remains to be elucidated. We have found that anti-human AKT antibodies recognized a protein of about 57 kDa in Leishmania spp. parasites. Anti-human phospho-AKT(Thr308) antibodies identified a protein in extracts from Leishmania spp. that was upregulated following parasite exposure to stressful conditions, such as nutrient deprivation or heat shock. Incubation of AKT inhibitor X with Leishmania spp. promastigotes under stressful conditions or with Leishmania-infected macrophages led to parasite cell death. We have identified and cloned a novel gene from Leishmania donovani named Ld-RAC/AKT-like gene, encoding a 510-amino acid protein of approximately 57.6 kDa that shows a 26.5% identity with mammalian AKT1. Ld-RAC/AKT-like protein contains major mammalian PKB/AKT hallmarks, including the typical pleckstrin, protein kinase and AGC kinase domains. Unlike mammalian AKT that contains key phosphorylation sites at Thr308 and Ser473 in the activation loop and hydrophobic motif, respectively, Ld-RAC/AKT-like protein has a Thr residue in both motifs. By domain sequence comparison, we classified AKT proteins from different origins in four major subcategories that included different parasites. Our data suggest that Ld-RAC/AKT-like protein represents a Leishmania orthologue of mammalian AKT involved in parasite stress response and survival, and therefore could become a novel therapeutic and druggable target in leishmaniasis therapy. In addition, following comparative sequence analyses, we found the RAC/AKT-like proteins from Leishmania constitute a subgroup by themselves within a general AKT-like protein family.
Histamine acting on H1 receptor promotes inhibition of proliferation via PLC, RAC, and JNK-dependent pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Notcovich, Cintia; Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires; Diez, Federico

2010-02-01

It is well established that histamine modulates cell proliferation through the activation of the histamine H1 receptor (H1R), a G protein-coupled receptor (GPCR) that is known to couple to phospholipase C (PLC) activation via Gq. In the present study, we aimed to determine whether H1R activation modulates Rho GTPases, well-known effectors of Gq/G{sub 11}-coupled receptors, and whether such modulation influences cell proliferation. Experiments were carried out in CHO cells stably expressing H1R (CHO-H1R). By using pull-down assays, we found that both histamine and a selective H1R agonist activated Rac and RhoA in a time- and dose-dependent manner without significant changesmore » in the activation of Cdc42. Histamine response was abolished by the H1R antagonist mepyramine, RGS2 and the PLC inhibitor U73122, suggesting that Rac and RhoA activation is mediated by H1R via Gq coupling to PLC stimulation. Histamine caused a marked activation of serum response factor activity via the H1R, as determined with a serum-responsive element (SRE) luciferase reporter, and this response was inhibited by RhoA inactivation with C3 toxin. Histamine also caused a significant activation of JNK which was inhibited by expression of the Rac-GAP {beta}2-chimaerin. On the other hand, H1R-induced ERK1/2 activation was inhibited by U73122 but not affected by C3 or {beta}2-chimaerin, suggesting that ERK1/2 activation was dependent on PLC and independent of RhoA or Rac. [{sup 3}H]-Thymidine incorporation assays showed that both histamine and the H1R agonist inhibited cell proliferation in a dose-dependent manner and that the effect was independent of RhoA but partially dependent on JNK and Rac. Our results reveal that functional coupling of the H1R to Gq-PLC leads to the activation of RhoA and Rac small GTPases and suggest distinct roles for Rho GTPases in the control of cell proliferation by histamine.« less
Ofloxacin induces apoptosis via β1 integrin-EGFR-Rac1-Nox2 pathway in microencapsulated chondrocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Zhi-Guo; Huang, Wei; Liu, Yu-Xiang

2013-02-15

Quinolones (QNs)-induced arthropathy is an important toxic side-effect in immature animals leading to the restriction of their therapeutic use in pediatrics. Ofloxacin, a typical QN, was found to induce the chondrocytes apoptosis in the early phase (12–48 h) of arthropathy in our previous study. However, the exact mechanism(s) is unclear. Microencapsulated juvenile rabbit joint chondrocytes, a three-dimensional culture system, is utilized to perform the present study. Ofloxacin, at a therapeutically relevant concentration (10 μg/ml), disturbs the interaction between β1 integrin and activated intracellular signaling proteins at 12 h, which is inhibited when supplementing Mg{sup 2+}. Intracellular reactive oxygen species (ROS)more » significantly increases in a time-dependent manner after exposure to ofloxacin for 12–48 h. Furthermore, ofloxacin markedly enhances the level of activated Rac1 and epidermal growth factor receptor (EGFR) phosphorylation, and its inhibition in turn reduces the ROS production, apoptosis and Rac1 activation. Silencing Nox2, Rac1 or supplementing Mg{sup 2+} inhibits ROS accumulation, apoptosis occurrence and EGFR phosphorylation induced by ofloxacin. However, depletion of Nox2, Rac1 and inhibition of EGFR do not affect ofloxacin-mediated loss of interaction between β1 integrin and activated intracellular signaling proteins. In addition, ofloxacin also induces Vav2 phosphorylation, which is markedly suppressed after inactivating EGFR or supplementing Mg{sup 2+}. These results suggest that ofloxacin causes Nox2-mediated intracellular ROS production by disrupting the β1 integrin function and then activating the EGFR-Vav2-Rac1 pathway, finally resulting in apoptosis within 12–48 h exposure. The present study provides a novel insight regarding the potential role of Nox-driven ROS in QNs-induced arthropathy. - Highlights: ► Ofloxacin induces Nox2-driven ROS in encapsulated chondrocyte at 12–48 h. ► Ofloxacin stimulates ROS production via the β1 integrin-EGFR-Vav2-Rac1 pathway. ► Ofloxacin induces ROS-dependent apoptosis in encapsulated chondrocyte at 12–48 h.« less
PI3K regulates MEK/ERK signaling in breast cancer via the Rac-GEF, P-Rex1

PubMed Central

Ebi, Hiromichi; Costa, Carlotta; Faber, Anthony C.; Nishtala, Madhuri; Kotani, Hiroshi; Juric, Dejan; Della Pelle, Patricia; Song, Youngchul; Yano, Seiji; Mino-Kenudson, Mari; Benes, Cyril H.; Engelman, Jeffrey A.

2013-01-01

The PI3K pathway is genetically altered in excess of 70% of breast cancers, largely through PIK3CA mutation and HER2 amplification. Preclinical studies have suggested that these subsets of breast cancers are particularly sensitive to PI3K inhibitors; however, the reasons for this heightened sensitivity are mainly unknown. We investigated the signaling effects of PI3K inhibition in PIK3CA mutant and HER2 amplified breast cancers using PI3K inhibitors currently in clinical trials. Unexpectedly, we found that in PIK3CA mutant and HER2 amplified breast cancers sensitive to PI3K inhibitors, PI3K inhibition led to a rapid suppression of Rac1/p21-activated kinase (PAK)/protein kinase C-RAF (C-RAF)/ protein kinase MEK (MEK)/ERK signaling that did not involve RAS. Furthermore, PI3K inhibition led to an ERK-dependent up-regulation of the proapoptotic protein, BIM, followed by induction of apoptosis. Expression of a constitutively active form of Rac1 in these breast cancer models blocked PI3Ki-induced down-regulation of ERK phosphorylation, apoptosis, and mitigated PI3K inhibitor sensitivity in vivo. In contrast, protein kinase AKT inhibitors failed to block MEK/ERK signaling, did not up-regulate BIM, and failed to induce apoptosis. Finally, we identified phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) as the PI(3,4,5)P3-dependent guanine exchange factor for Rac1 responsible for regulation of the Rac1/C-RAF/MEK/ERK pathway in these cells. The expression level of P-Rex1 correlates with sensitivity to PI3K inhibitors in these breast cancer cell lines. Thus, PI3K inhibitors have enhanced activity in PIK3CA mutant and HER2 amplified breast cancers in which PI3K inhibition down-regulates both the AKT and Rac1/ERK pathways. In addition, P-Rex1 may serve as a biomarker to predict response to single-agent PI3K inhibitors within this subset of breast cancers. PMID:24327733
75 FR 64741 - Notice of Utah's Resource Advisory Council (RAC) Subcommittee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-20

...In accordance with the Federal Land Policy and Management Act (FLPMA) and the Federal Advisory Committee Act of 1972, the U.S. Department of the Interior, Bureau of Land Management's (BLM) Utah Resource Advisory Council (RAC) Subcommittee will meet as indicated below.
Science: The Recombinant DNA Advisory Committee.

ERIC Educational Resources Information Center

Wright, Susan

1979-01-01

Reports on the status of the Recombinant DNA Advisory Committee (RAC) and attempts to rationalize Suburban Highway Policy. Effective communication among members of the RAC is a current problem facing the committee. A federal transportation priority spending policy is suggested during these times of money and fuel shortages. (MA)
75 FR 49457 - Amador County Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

... approval and implementation, and conduct RAC management business. DATES: The meetings will be held on.... SUPPLEMENTARY INFORMATION: The meeting is open to the public. The following business will be conducted: At that... implementation and conduct RAC management buiness. More information will be posted on the Eldorado National...

Prognostic role of integrin β1, E-cadherin, and rac1 expression in small cell lung cancer.

PubMed

Chang, Myung Hee; Lee, Kyungji; Lee, Kyo-Young; Kim, Yeon Sil; Kim, Young Kyoon; Kang, Jin-Hyoung

2012-01-01

Integrin β(1) mediates cellular adhesion to the extracellular matrix (ECM) and is correlated with highly invasive and metastatic behavior in small cell lung cancer (SCLC). E-cadherin (ECAD) is a calcium-dependent cell-cell adhesion receptor that restricts invasion of cells and reduces metastasis. Rac1 is involved in the regulation of the actin cytoskeleton, adhesion, migration, invasion, and tumor metastasis. The aim of this study was to examine integrin β(1) , ECAD and rac1 expression in SCLC and to analyze the prognostic value of these markers in patients with SCLC. We analyzed integrin β(1) , ECAD, and rac1 expression in 112 SCLC tissues by immunohistochemical staining. Correlative analyses between integrin β(1) , ECAD, and rac1 expression and cliniopathological factors were performed. A total of 65 patients had extensive disease (ED) (58%), and 47 had limited disease (LD) (42%). The median follow-up duration was 61 months (range: 14-117 months), and the median progression free survival (PFS) and overall survival (OS) were 6.1 months (range: 4.8-7.4 months) and 9.7 months (range: 8.1-11.3 months), respectively. The expression of integrin β(1) , ECAD, and rac1 protein was observed in 64, 73, and 99 of SCLC tissues, respectively. The correlative analyses between integrin β(1) , ECAD, or rac1 expression and various clinical parameters did not show any statistical significance. However, the ECAD expression was associated with OS in the entire cohort. In contrast, the expression of integrin β(1) and rac1 was not associated with PFS or OS. In a subgroup analysis, patients with less than two metastasis had significantly longer OS (p = 0.047) if their tumors expressed integrin β(1) compared to those without integrin β(1) expression. In addition, OS was longer for patients with ECAD positive tumors compared to those whose tumors did not express ECAD in males (p = 0.032) and patients who never smoked (p < 0.001). Multivariate analysis showed that LD (p = 0.004), overall response rate (p = 0.003), and expression of ECAD (p = 0.015) were the independent good prognostic factors for OS. LD (p = 0.024), overall response rate (p < 0.001), and less than two metastasis (p = 0.003) were prognostic factors for longer PFS. These results suggest that ECAD expression may be useful as a prognostic indicator in patients with SCLC. © 2011 The Authors. APMIS © 2011 APMIS.
Effects of ractopamine hydrochloride on growth performance, carcass characteristics, and physiological response to different handling techniques.

PubMed

Hagenmaier, J A; Reinhardt, C D; Ritter, M J; Calvo-Lorenzo, M S; Vogel, G J; Guthrie, C A; Siemens, M G; Lechtenberg, K F; Rezac, D J; Thomson, D U

2017-05-01

Feedlot cattle ( = 128; BW = 549 ± 60 kg) were used to evaluate the effects of ractopamine hydrochloride (RAC) on growth performance, physiological response to handling, and mobility during shipment for slaughter in a study utilizing a split-plot design with a 2 × 2 factorial arrangement of treatments: 1) diet (CON [no β-adrenergic agonist] vs. RAC [400 mg·animal·d ractopamine hydrochloride for 28 d]) and 2) handling intensity (HI; low-stress handling [LSH; cattle moved at a walking pace with no electric prod use] vs. high-stress handling [HSH; cattle moved at a minimum of a trot and an electric prod applied while in the alley for posthandling restraint and during loading for shipment to the abattoir]). Cattle fed RAC tended to have greater ADG and G:F ( = 0.06), and had greater HCW and LM area ( = 0.04). The HI treatments were applied on the day after the 28-d growth performance period. Blood samples were collected before HI treatment (baseline), after HI treatments (POSTHAND), after transport to the abattoir (POSTTRANS), and during exsanguination at slaughter. A diet × HI interaction ( = 0.01) was observed in the change in cortisol from baseline to POSTTRANS, and there tended ( ≤ 0.07) to be diet × HI interactions for the change in epinephrine from baseline to POSTHAND and for the change in creatine kinase (CK) from baseline to POSTTRANS. Feeding RAC and HSH both increased the change from baseline to POSTHAND in norepinephrine and pH ( ≤ 0.05). The HSH cattle also had greater changes from baseline to POSTHAND in blood HCO, base excess, partial pressure of CO, lactate, cortisol, and glucose ( ≤ 0.01). Ractopamine and HSH both produced greater increases in CK concentrations from baseline to slaughter ( < 0.01). Mobility was not affected by RAC at the feedlot or following an average 6-h lairage ( ≥ 0.43). This study confirms RAC improves growth performance and suggests metabolic acidosis, a precursor to fatigued cattle syndrome, develops in cattle allowed to trot without the use of a lead rider regardless of RAC administration. Cattle fed RAC displayed altered hormonal responses to handling and transport stress, and the overall proportion of cattle with compromised mobility appears to increase later in the marketing channel. These findings warrant additional research aimed at better understanding the physiological response to stress and protect the welfare of cattle during shipment for slaughter.
The Aged Residential Care Healthcare Utilization Study (ARCHUS): a multidisciplinary, cluster randomized controlled trial designed to reduce acute avoidable hospitalizations from long-term care facilities.

PubMed

Connolly, Martin J; Boyd, Michal; Broad, Joanna B; Kerse, Ngaire; Lumley, Thomas; Whitehead, Noeline; Foster, Susan

2015-01-01

To assess effect of a complex, multidisciplinary intervention aimed at reducing avoidable acute hospitalization of residents of residential aged care (RAC) facilities. Cluster randomized controlled trial. RAC facilities with higher than expected hospitalizations in Auckland, New Zealand, were recruited and randomized to intervention or control. A total of 1998 residents of 18 intervention facilities and 18 control facilities. A facility-based complex intervention of 9 months' duration. The intervention comprised gerontology nurse specialist (GNS)-led staff education, facility bench-marking, GNS resident review, and multidisciplinary (geriatrician, primary-care physician, pharmacist, GNS, and facility nurse) discussion of residents selected using standard criteria. Primary end point was avoidable hospitalizations. Secondary end points were all acute admissions, mortality, and acute bed-days. Follow-up was for a total of 14 months. The intervention did not affect main study end points: number of acute avoidable hospital admissions (RR 1.07; 95% CI 0.85-1.36; P = .59) or mortality (RR 1.11; 95% CI 0.76-1.61; P = .62). This multidisciplinary intervention, packaging selected case review, and staff education had no overall impact on acute hospital admissions or mortality. This may have considerable implications for resourcing in the acute and RAC sectors in the face of population aging. Australian and New Zealand Clinical Trials Registry (ACTRN12611000187943). Copyright © 2015 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.
Chilling Prospect: Climate Change Effects of Mismanaged Refrigerants in China.

PubMed

Duan, Huabo; Miller, T Reed; Liu, Gang; Zeng, Xianlai; Yu, Keli; Huang, Qifei; Zuo, Jian; Qin, Yufei; Li, Jinhui

2018-06-05

The global community has responded to the dual threats of ozone depletion and climate change from refrigerant emissions (e.g., chlorofluorocarbons, CFCs, and hydrofluorocarbons, HFCs) in refrigerators and air conditioners (RACs) by agreeing to phase out the production of the most damaging chemicals and replacing them with substitutes. Since these refrigerants are "banked" in products during their service life, they will continue to impact our environment for decades to come if they are released due to mismanagement at the end of life. Addressing such long-term impacts of refrigerants requires a dynamic understanding of the RACs' life cycle, which was largely overlooked in previous studies. Based on field surveys and a dynamic model, we reveal the lingering ozone depletion potential (ODP) and significant global warming potential (GWP) of scrap refrigerants in China, the world's largest producer (62%) and consumer (46%) of RACs in 2015, which comes almost entirely from air conditioners rather than refrigerators. If the use and waste management of RACs continue with the current trend, the total GWP of scrap refrigerants in China will peak by 2025 at a level of 135.2 ± 18.9 Mt CO 2 e (equal to approximately 1.2% ± 0.2% of China's total greenhouse gas emissions or the national total of either The Netherlands and Czech Republic in 2015). Our results imply an urgent need for improving the recycling and waste management of RACs in China.
Staphylococcus aureus keratinocyte invasion is mediated by integrin-linked kinase and Rac1.

PubMed

Sayedyahossein, Samar; Xu, Stacey X; Rudkouskaya, Alena; McGavin, Martin J; McCormick, John K; Dagnino, Lina

2015-02-01

Staphylococcus aureus is a major component of the skin microbiota and causes a large number of serious infections. S. aureus first interacts with epidermal keratinocytes to breach the epidermal barrier through mechanisms not fully understood. By use of primary keratinocytes from mice with epidermis-restricted Ilk gene inactivation and control integrin-linked kinase (ILK)-expressing littermates, we investigated the role of ILK in epidermal S. aureus invasion. Heat-killed, but not live, bacteria were internalized to Rab5- and Rab7-positive phagosomes, and incubation with keratinocyte growth factor increased their uptake 2.5-fold. ILK-deficient mouse keratinocytes internalized bacteria 2- to 4-fold less efficiently than normal cells. The reduced invasion by live S. aureus of ILK-deficient cells was restored in the presence of exogenous, constitutively active Rac1. Thus, Rac1 functions downstream from ILK during invasion. Further, invasion by S. aureus of Rac1-deficient cells was 2.5-fold lower than in normal cells. Paradoxically, staphylococcal cutaneous penetration of mouse skin explants with ILK-deficient epidermis was 35-fold higher than that of normal skin, indicating defects in epidermal barrier function in the absence of ILK. Thus, we identified an ILK-Rac1 pathway essential for bacterial invasion of keratinocytes, and established ILK as a key contributor to prevent invasive staphylococcal cutaneous infection. © FASEB.
Manipulating the stride length/stride velocity relationship of walking using a treadmill and rhythmic auditory cueing in non-disabled older individuals. A short-term feasibility study.

PubMed

Eikema, D J A; Forrester, L W; Whitall, J

2014-09-01

One target for rehabilitating locomotor disorders in older adults is to increase mobility by improving walking velocity. Combining rhythmic auditory cueing (RAC) and treadmill training permits the study of the stride length/stride velocity ratio (SL/SV), often reduced in those with mobility deficits. We investigated the use of RAC to increase velocity by manipulating the SL/SV ratio in older adults. Nine participants (6 female; age: 61.1 ± 8.8 years) walked overground on a gait mat at preferred and fast speeds. After acclimatization to comfortable speed on a treadmill, participants adjusted their cadence to match the cue for 3 min at 115% of preferred speed by either (a) increasing stride length only or (b) increasing stride frequency only. Following training, participants walked across the gait mat at preferred velocity without, and then with, RAC. Group analysis determined no immediate overground velocity increase, but reintroducing RAC did produce an increase in velocity after both conditions. Group and single subject analysis determined that the SL/SV ratio changed in the intended direction only in the stride length condition. We conclude that RAC is a powerful organizer of gait parameters, evidenced by its induced after-effects following short duration training. Copyright © 2014 Elsevier B.V. All rights reserved.
Reorganization of Actin Cytoskeleton by the Phosphoinositide Metabolite Glycerophosphoinositol 4-Phosphate

PubMed Central

Mancini, Raffaella; Piccolo, Enza; Mariggio', Stefania; Filippi, Beatrice Maria; Iurisci, Cristiano; Pertile, Paolo; Berrie, Christopher P.; Corda, Daniela

2003-01-01

Glycerophosphoinositol 4-phosphate (GroPIns-4P) is a biologically active, water-soluble phospholipase A metabolite derived from phosphatidylinositol 4-phosphate, whose cellular concentrations have been reported to increase in Ras-transformed cells. It is therefore important to understand its biological activities. Herein, we have examined whether GroPIns-4P can regulate the organization of the actin cytoskeleton, because this could be a Ras-related function involved in cell motility and metastatic invasion. We find that in serum-starved Swiss 3T3 cells, exogenously added GroPIns-4P rapidly and potently induces the formation of membrane ruffles, and, later, the formation of stress fibers. These actin structures can be regulated by the small GTPases Cdc42, Rac, and Rho. To analyze the mechanism of action of GroPIns-4P, we selectively inactivated each of these GTPases. GroPIns-4P requires active Rac and Rho, but not Cdc42, for ruffle and stress fiber formation, respectively. Moreover, GroPIns-4P induces a rapid translocation of the green fluorescent protein-tagged Rac into ruffles, and increases the fraction of GTP-bound Rac, in intact cells. The activation of Rac by GroPIns-4P was near maximal and long-lasting. Interestingly, this feature seems to be critical in the induction of actin ruffles by GroPIns-4P. PMID:12589050
Randomized clinical trial of robot-assisted versus standard laparoscopic right colectomy.

PubMed

Park, J S; Choi, G-S; Park, S Y; Kim, H J; Ryuk, J P

2012-09-01

Robotic surgery was invented to overcome the demerits of laparoscopic technique. However, it is unclear whether robot-assisted colectomy (RAC) has significant clinical advantages over laparoscopically assisted colectomy (LAC) in treating colonic cancer. The aim of this study was to compare the surgical outcomes of RAC versus LAC for right-sided colonic cancer. Patients with right-sided colonic cancer were randomized to receive RAC or LAC. The primary outcome measure was length of hospital stay. Secondary outcomes were duration of operation, morbidity, postoperative pain, hospital costs and pathological quality of the specimen. Of 71 patients randomized, 70 (35 in each group) were included in the analysis. Hospital stay, surgical complications, postoperative pain score, resection margin clearance and number of lymph nodes harvested were similar in both groups. The duration of surgery was longer in the RAC group (195 versus 130 min; P < 0·001). No conversion to open surgery was needed in either group. Overall hospital costs were significantly higher for RAC (US $ 12,235 versus $ 10,320; P = 0·013); the higher costs were attributed primarily to the costs of surgery, including consumables. Robotic-assisted laparoscopic right colectomy was feasible but provided no benefit to justify the greater cost. NCT01042743 (http://www.clinicaltrials.gov). Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
ADP-Ribosylation Factor 6 and a Functional PIX/p95-APP1 Complex Are Required for Rac1B-mediated Neurite Outgrowth

PubMed Central

Albertinazzi, Chiara; Za, Lorena; Paris, Simona; de Curtis, Ivan

2003-01-01

The mechanisms coordinating adhesion, actin organization, and membrane traffic during growth cone migration are poorly understood. Neuritogenesis and branching from retinal neurons are regulated by the Rac1B/Rac3 GTPase. We have identified a functional connection between ADP-ribosylation factor (Arf) 6 and p95-APP1 during the regulation of Rac1B-mediated neuritogenesis. P95-APP1 is an ADP-ribosylation factor GTPase-activating protein (ArfGAP) of the GIT family expressed in the developing nervous system. We show that Arf6 has a predominant role in neurite extension compared with Arf1 and Arf5. Cotransfection experiments indicate a specific and cooperative potentiation of neurite extension by Arf6 and the carboxy-terminal portion of p95-APP1. Localization studies in neurons expressing different p95-derived constructs show a codistribution of p95-APP1 with Arf6, but not Arf1. Moreover, p95-APP1–derived proteins with a mutated or deleted ArfGAP domain prevent Rac1B-induced neuritogenesis, leading to PIX-mediated accumulation at large Rab11-positive endocytic vesicles. Our data support a role of p95-APP1 as a specific regulator of Arf6 in the control of membrane trafficking during neuritogenesis. PMID:12686588
Recovery of V(V) from complex vanadium solution using capacitive deionization (CDI) with resin/carbon composite electrode.

PubMed

Bao, Shenxu; Duan, Jihua; Zhang, Yimin

2018-05-25

The resin-activated carbon composite (RAC) electrodes were fabricated and applied in capacitive deionization for recovery of V(V) from complex vanadium solution. The adsorption capacity of the RAC electrode for V(V) is extremely low and the reduction of V(V) is significant in low pH solution, but the adsorbed V(V) on the electrode increases obviously and the reduction of V(V) gradually diminishes with the rise of pH. However, as the pH is increased to 10, the adsorbed V(V) on the RAC electrode declines. The higher applied potential is beneficial to the adsorption of V(V) and 1.0 V is appropriate for the adsorption. The impurities ions (Al, P and Si) are mainly adsorbed in the electric double layers on the RAC electrode and V(V) is dominantly adsorbed by the resins in the electrode. The adsorbed impurity ions can be easily removed by diluted H 2 SO 4 and V(V) can be effectively eluted by 10% NaOH solution. The vanadium-bearing eluent can be recycled to recover and enrich vanadium from the complex solution. The performance of the RAC electrode keeps stable during the cyclic operation. This study may provide a promising and novel method for the recovery and separation of metals from aqueous solution. Copyright © 2018 Elsevier Ltd. All rights reserved.
77 FR 14041 - Southeast Oregon Resource Advisory Council; Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

...; HAG 12-0102] Southeast Oregon Resource Advisory Council; Meeting AGENCY: Bureau of Land Management... Land Management, the Southeast Oregon Resource Advisory Council (RAC) will meet as indicated below: DATES: The Southeast Oregon RAC will hold a public meeting Monday, April 2, 2012, from 12 p.m. to 4:30 p...
76 FR 28442 - Office of the Director, National Institutes of Health; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-17

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Office of the Director.... Agenda: The NIH Recombinant DNA Advisory Committee (RAC) will review and discuss selected human gene... Advisory Committee (RAC) will review and discuss selected human gene transfer protocols, including a...
77 FR 43353 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-24

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) and...: On August 16, 2012, the Twin Falls District RAC subcommittee members for the proposed Monument and...
75 FR 60477 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-30

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... (BLM) Twin Falls District Resource Advisory Council (RAC) subcommittee for the Jarbidge Draft Resource...; and December 1, 2010. The Twin Falls District RAC subcommittee members will meet at the Loong Hing...
75 FR 48723 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-11

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... (BLM) Twin Falls District Resource Advisory Council (RAC) and subcommittees will meet as indicated below. DATES: On September 9, 2010, the Twin Falls District RAC subcommittee members will meet at the...
77 FR 37705 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-22

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) and...: On July 10, 2012, the Twin Falls District RAC subcommittee members for the proposed Monument and...
77 FR 15388 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-15

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) and...: On March 28, 2012, the Twin Falls District RAC subcommittee members for the proposed Monument and...
75 FR 80839 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-23

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... (BLM) Twin Falls District Resource Advisory Council (RAC) and subcommittee for the Jarbidge Resource... 12, 2011, the Twin Falls District RAC subcommittee members will meet at the Loong Hing Restaurant...
77 FR 17093 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... Public Meeting, Idaho Falls District Resource Advisory Council AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Salmon, Idaho on April 24-25...
Responsible Adult Culture (RAC): Cognitive and Behavioral Changes at a Community-Based Correctional Facility

ERIC Educational Resources Information Center

Devlin, Renee S.; Gibbs, John C.

2010-01-01

This article examined cognitive and behavioral changes among participants in Responsible Adult Culture (RAC), a cognitive-behavioral (especially, cognitive restructuring) treatment program in use at the Franklin County Community-Based Correctional Facility (CBCF). Participants were adult felony offenders (approximately three-fourths male). A…

Field operational test of the Freightliner/Meritor WABCO roll stability advisor and control at Praxair

DOT National Transportation Integrated Search

2003-08-01

This document reports on the conduct and findings of a naturalistic field operational test (FOT) of the Freightliner/Meritor WABCO Roll Stability Advisor and Control (RA&C). The broad intent of RA&C is to reduce the risk of rollover by improving driv...
Southwest Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

The Educational Technical Assistance Act of 2002, authorized the Southwest Regional Advisory Committee (RAC), whose members represent the states of Arkansas, Louisiana, New Mexico, Oklahoma, and Texas, to identify and prioritize the region's educational needs and recommend how those needs can be met. The Southwest RAC conducted three public…
78 FR 70960 - Utah Resource Advisory Council Meeting/Conference Call

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-27

... the teleconference, or submit written material for the RAC to consider during the teleconference... close of business, Monday, Jan. 6, 2014. SUPPLEMENTARY INFORMATION: The Utah RAC will elect officers for... Draft Land Use Plan Amendment and Environmental Impact Statement and to submit a draft comment letter to...
In vivo dopaminergic and serotonergic dysfunction in DCTN1 gene mutation carriers

PubMed Central

Felicio, Andre C.; Dinelle, Katherine; Agarwal, Pankaj A.; McKenzie, Jessamyn; Heffernan, Nicole; Road, Jeremy D.; Appel-Cresswell, Silke; Wszolek, Zbigniew K.; Farrer, Matthew J.; Schulzer, Michael; Sossi, Vesna; Stoessl, A. Jon

2014-01-01

Introduction We have used positron emission tomography (PET) to assess dopaminergic and serotonergic terminal density in three subjects carrying a mutation in the DCT1 gene, two clinically affected with Perry syndrome. Methods All subjects had brain imaging using 18F-6-fluoro-L-dopa (FDOPA, dopamine synthesis and storage), (+)-11C-dihydrotetrabenazine (DTBZ, vesicular monoamine transporter type 2), and 11C-raclopride (RAC, dopamine D2/D3 receptors). One subject also underwent PET with 11C-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile (DASB, serotonin transporter). Results FDOPA-PET and DTBZ-PET in the affected individuals showed a reduction of striatal tracer uptake. Also, RAC-PET showed higher uptake in these area. DASB-PET showed significant uptake changes in left orbitofrontal cortex, bilateral anterior insula, left dorsolateral prefrontal cortex, left orbitofrontal cortex, left posterior cingulate cortex, left caudate and left ventral striatum. Conclusions Our data showed evidence of both striatal dopaminergic and widespread cortical/subcortical serotonergic dysfunctions in individuals carrying a mutation in the DCTN1 gene. PMID:24797316
A Report to the U.S. Department of Education on Educational Challenges and Technical Assistance Needs for the Pacific Region

ERIC Educational Resources Information Center

CNA Corporation, 2005

2005-01-01

This report of the Pacific Regional Advisory Committee (RAC) provides an assessment of the technical assistance needs of educators in the Pacific region in response to a directive from the Secretary of the U.S. Department of Education (ED). This information will be used to assist in the establishment of 20 comprehensive centers providing technical…
75 FR 51840 - State of Arizona Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-23

... Policy and Management Act of 1976 and the Federal Advisory Committee Act of 1972, the U.S. Department of... implemented; RAC questions on BLM District Managers' Reports; and reports by RAC working groups. A public...) Working Group Report, REA Working Group meeting schedule and future BLM/FS recreation fee proposals. The...
Catalytic Role Of Palladium And Relative Reactivity Of Substituted Chlorines During Adsorption And Treatment Of PCBs On Reactive Activated Carbon

EPA Science Inventory

The adsorption-mediated dechlorination of polychlorinated biphenyls (PCBs) is a unique feature of reactive activated cabon (RAC). Here, we address the RAC system, containing a tunable amount of Fe as a primary electron donor coupled with Pd as an electrochemical catalyst to pote...
76 FR 10389 - Reopening the Call for Nominations for the New Mexico Albuquerque and Farmington District...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-24

... Call for Nominations for the New Mexico Albuquerque and Farmington District Resource Advisory Councils... reopen the nomination period for the Bureau of Land Management's (BLM) Albuquerque, New Mexico, and Farmington, New Mexico, Resource Advisory Councils (RAC). The RACs provide advice and recommendations to the...
77 FR 75653 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-21

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) will meet as indicated below. DATES: On January 31, 2013, the Twin Falls District RAC members will meet at...
76 FR 48883 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-09

...] Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land... of the Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Challis, Idaho...
76 FR 26314 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... (BLM) Twin Falls District Resource Advisory Council (RAC) will meet as indicated below. DATES: May 16, 2011. On May 16, 2011, the Twin Falls District RAC members will meet at the Best Western Sawtooth Inn...
78 FR 19522 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-01

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Challis, Idaho, April 23-24...
75 FR 27360 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-14

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Salmon, Idaho on June 22-23...
76 FR 76179 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-06

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The RAC will next meet in Idaho Falls, Idaho on January 24-25, 2012 for a...
77 FR 49826 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-17

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Idaho Falls, Idaho on September...
78 FR 68467 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, ID

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

... of Public Meetings, Twin Falls District Resource Advisory Council, ID AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) and..., the Twin Falls District RAC subcommittee members for the Greater sage-grouse will meet at the Twin...
78 FR 56242 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-12

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) will meet as indicated below. DATES: On September 26, 2013, the Twin Falls District RAC members will meet at...
76 FR 30388 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-25

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... (BLM) Twin Falls District Resource Advisory Council (RAC) will meet as indicated below. DATES: June 21-22, 2011. On June 21, 2011, the Twin Falls District RAC members will meet at the Idaho Commerce and...
76 FR 79707 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-22

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... (BLM) Twin Falls District Resource Advisory Council (RAC) and subcommittee for the Jarbidge Resource Management Plan (RMP) will meet as indicated below. DATES: On January 25, 2012, the Twin Falls District RAC...
77 FR 74203 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-13

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The RAC will next meet in Idaho Falls, Idaho on January 22-23, 2013 for a...

78 FR 38071 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-25

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Pocatello, Idaho, August 27-28...
78 FR 19732 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-02

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) will meet as indicated below. DATES: On April 23 2013, the Twin Falls District RAC members will meet at the...
76 FR 3651 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-20

...] Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land... of the Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The RAC will next meet in Idaho Falls, Idaho, on February 15-16...
78 FR 17716 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-22

... Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land Management... Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Challis, Idaho, April 23-24...
76 FR 28805 - Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-18

...] Notice of Public Meeting, Idaho Falls District Resource Advisory Council Meeting AGENCY: Bureau of Land... of the Interior, Bureau of Land Management (BLM) Idaho Falls District Resource Advisory Council (RAC), will meet as indicated below. DATES: The Idaho Falls District RAC will meet in Pocatello, Idaho on June...
78 FR 32440 - Notice of Public Meetings, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-30

... of Public Meetings, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of Land... the Interior, Bureau of Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) will meet as indicated below. DATES: On June 20, 2013, the Twin Falls District RAC members will meet at the...
76 FR 24854 - Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-03

... DEPARTMENT OF AGRICULTURE Forest Service Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: Pursuant to the authorities in the Federal Advisory Committees Act (Pub. L. 92-463), the Northeast Oregon...
75 FR 5563 - Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-03

... DEPARTMENT OF AGRICULTURE Forest Service Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: Pursuant to the authorities in the Federal Advisory Committees Act (Pub. L. 92-463), the Northeast Oregon...
75 FR 33241 - Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-11

... DEPARTMENT OF AGRICULTURE Forest Service Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: Pursuant to the authorities in the Federal Advisory Committees Act (Pub. L. 92-463), the Northeast Oregon...
Northeast and Islands Region: A Report Identifying and Addressing the Educational Needs

ERIC Educational Resources Information Center

US Department of Education, 2011

2011-01-01

This report discusses the deliberations of the Northeast and Islands (NEI) Regional Advisory Committee (RAC), one of 10 RACs established by the U.S. Department of Education to solicit information about the educational needs of state and local educators, school officials, business leaders, state education agencies, parents, local communities, and…
40 CFR 180.1122 - Inert ingredients of semiochemical dispensers; exemptions from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1122 Inert ingredients of semiochemical... (including the monomers, plasticizers, dispersing agents, antioxidants, UV protectants, stabilizers, and... commodity (RAC) or processed foods/feeds derived from the commodity by virtue of its proximity to the RAC or...
40 CFR 180.1122 - Inert ingredients of semiochemical dispensers; exemptions from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1122 Inert ingredients of semiochemical... (including the monomers, plasticizers, dispersing agents, antioxidants, UV protectants, stabilizers, and... commodity (RAC) or processed foods/feeds derived from the commodity by virtue of its proximity to the RAC or...
76 FR 73658 - Reopening the Call for Nominations for the Albuquerque District Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-29

... Call for Nominations for the Albuquerque District Resource Advisory Council AGENCY: Bureau of Land... for the Bureau of Land Management's (BLM) Albuquerque District Resource Advisory Council (RAC) in Category 3. The Albuquerque RAC provides advice and recommendations to the BLM on land use planning and...
Can a web-based community of practice be established and operated to lead falls prevention activity in residential care?

PubMed

Francis-Coad, Jacqueline; Etherton-Beer, Christopher; Bulsara, Caroline; Nobre, Debbie; Hill, Anne-Marie

The aims of this study were to evaluate establishing and operating a web-based community of practice (CoP) to lead falls prevention in a residential aged care (RAC) setting. A mixed methods evaluation was conducted in two phases using a survey and transcripts from interactive electronic sources. Nurses and allied health staff (n = 20) with an interest in falls prevention representing 13 sites of an RAC organization participated. In Phase 1, the CoP was developed, and the establishment of its structure and composition was evaluated using determinants of success reported in the literature. In Phase 2, all participants interacted using the web, but frequency of engagement by any participant was low. Participatory barriers, including competing demands from other tasks and low levels of knowledge about information communication technology (ICT) applications, were identified by CoP members. A web-based CoP can be established and operated across multiple RAC sites if RAC management support dedicated time for web-based participation and staff are given web-based training. Copyright © 2016 Elsevier Inc. All rights reserved.
Deletion of Wiskott–Aldrich syndrome protein triggers Rac2 activity and increased cross-presentation by dendritic cells

PubMed Central

Baptista, Marisa A. P.; Keszei, Marton; Oliveira, Mariana; Sunahara, Karen K. S.; Andersson, John; Dahlberg, Carin I. M.; Worth, Austen J.; Liedén, Agne; Kuo, I-Chun; Wallin, Robert P. A.; Snapper, Scott B.; Eidsmo, Liv; Scheynius, Annika; Karlsson, Mikael C. I.; Bouma, Gerben; Burns, Siobhan O.; Forsell, Mattias N. E.; Thrasher, Adrian J.; Nylén, Susanne; Westerberg, Lisa S.

2016-01-01

Wiskott–Aldrich syndrome (WAS) is caused by loss-of-function mutations in the WASp gene. Decreased cellular responses in WASp-deficient cells have been interpreted to mean that WASp directly regulates these responses in WASp-sufficient cells. Here, we identify an exception to this concept and show that WASp-deficient dendritic cells have increased activation of Rac2 that support cross-presentation to CD8+ T cells. Using two different skin pathology models, WASp-deficient mice show an accumulation of dendritic cells in the skin and increased expansion of IFNγ-producing CD8+ T cells in the draining lymph node and spleen. Specific deletion of WASp in dendritic cells leads to marked expansion of CD8+ T cells at the expense of CD4+ T cells. WASp-deficient dendritic cells induce increased cross-presentation to CD8+ T cells by activating Rac2 that maintains a near neutral pH of phagosomes. Our data reveals an intricate balance between activation of WASp and Rac2 signalling pathways in dendritic cells. PMID:27425374
Molecular Dynamic Simulation Reveals Damaging Impact of RAC1 F28L Mutation in the Switch I Region

PubMed Central

Sethumadhavan, Rao; Purohit, Rituraj

2013-01-01

Ras-related C3 botulinum toxin substrate 1 (RAC1) is a plasma membrane-associated small GTPase which cycles between the active GTP-bound and inactive GDP-bound states. There is wide range of evidences indicating its active participation in inducing cancer-associated phenotypes. RAC1 F28L mutation (RACF28L) is a fast recycling mutation which has been implicated in several cancer associated cases. In this work we have performed molecular docking and molecular dynamics simulation (~0.3 μs) to investigate the conformational changes occurring in the mutant protein. The RMSD, RMSF and NHbonds results strongly suggested that the loss of native conformation in the Switch I region in RAC1 mutant protein could be the reason behind its oncogenic transformation. The overall results suggested that the mutant protein attained compact conformation as compared to the native. The major impact of mutation was observed in the Switch I region which might be the crucial reason behind the loss of interaction between the guanine ring and F28 residue. PMID:24146998
Distribution and Depletion of Ractopamine in Goat Plasma, Urine and Various Muscle Tissues.

PubMed

Zhao, Zhen; Gu, Xu; Su, Xiaoou; Li, Junguo; Li, Jun; Dong, Yingchao; Yang, Yujuan; Yao, Ting; Qin, Yuchang

2017-01-01

This study investigated the ractopamine (RAC) distribution and depletion process in goat plasma, urine and various muscle tissues which were associated with a potential risk for consumer health. The experiment was carried out in 21 goats (18 treated and 3 controls). Treated animals were administered orally a dose of 1 mg/kg body mass per day for 28 consecutive days and randomly sacrificed on Days 0.25, 1, 3, 7, 14 and 21 of the withdrawal period. RAC in goat samples was analyzed by using ultra-high performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrometry. RAC was below the limits of detection (LOD = 0.15 ng/mL) in plasma while which was higher than the LOD in urine on withdrawal day 21. The residues in goat longissimus dorsi muscle, biceps femoris muscle and triceps surae muscle were differed significantly. These findings demonstrated that urine can be used as the target matrix for monitoring RAC abuse in goat. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
A family affair: A Ral-exocyst-centered network links Ras, Rac, Rho signaling to control cell migration.

PubMed

Zago, Giulia; Biondini, Marco; Camonis, Jacques; Parrini, Maria Carla

2017-05-12

Cell migration is central to many developmental, physiologic and pathological processes, including cancer progression. The Ral GTPases (RalA and RalB) which act down-stream the Ras oncogenes, are key players in the coordination between membrane trafficking and actin polymerization. A major direct effector of Ral, the exocyst complex, works in polarized exocytosis and is at the center of multiple protein-protein interactions that support cell migration by promoting protrusion formation, front-rear polarization, and extra-cellular matrix degradation. In this review we describe the recent advancements in deciphering the molecular mechanisms underlying this role of Ral via exocyst on cell migration. Among others, we will discuss the recently identified cross-talk between Ral and Rac1 pathways: exocyst binds to a negative regulator (the RacGAP SH3BP1) and to the major effector (the Wave Regulatory Complex, WRC) of Rac1, the master regulator of protrusions. Next challenge will be to better characterize the dynamics in space and in time of these molecular interplays, to better understand the pleiotropic functions of Ral in both normal and cancer cells.
The small GTPase Rac and the p21-activated kinase Cla4 in Claviceps purpurea: interaction and impact on polarity, development and pathogenicity.

PubMed

Rolke, Yvonne; Tudzynski, Paul

2008-04-01

Claviceps purpurea, the ergot fungus, is a highly specialized pathogen of grasses; its colonization of host ovarian tissue requires an extended period of strictly polarized, oriented growth towards the vascular tissue. To understand this process, we study the role of signalling factors affecting polarity and differentiation. We showed that the small GTPase Cdc42 is involved in polarity, sporulation and in planta growth in C. purpurea. Here we present evidence that the GTPase Rac has an even stronger and, in some aspects, inverse impact on growth and development: Deltarac mutants form coralline-like colonies, show hyper-branching, loss of polarity, sporulation and ability to penetrate. Functional analyses and yeast two-hybrid studies prove that the p21-activated kinase Cla4 is a major downstream partner of Rac. Phosphorylation assays of MAP kinases and expression studies of genes encoding reactive oxygen species (ROS)-scavenging and -generating enzymes indicate a function of Rac and Cla4 in fungal ROS homoeostasis which could contribute to their drastic impact on differentiation.
Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3- and KIT-Driven Leukemogenesis.

PubMed

Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Mali, Raghuveer Singh; Martin, Holly; Kobayashi, Michihiro; Vemula, Sasidhar; Canela, Victor H; Waskow, Emily R; Visconte, Valeria; Tiu, Ramon V; Smith, Catherine C; Shah, Neil; Bunting, Kevin D; Boswell, H Scott; Liu, Yan; Chan, Rebecca J; Kapur, Reuben

2014-11-20

Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPNs), and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription, is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK) whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Rac interacts with Abi-1 and WAVE2 to promote an Arp2/3-dependent actin recruitment during chlamydial invasion.

PubMed

Carabeo, Rey A; Dooley, Cheryl A; Grieshaber, Scott S; Hackstadt, Ted

2007-09-01

Chlamydiae are Gram-negative obligate intracellular pathogens to which access to an intracellular environment is fundamental to their development. Chlamydial attachment to host cells induces the activation of the Rac GTPase, which is required for the localization of WAVE2 at the sites of chlamydial entry. Co-immunoprecipitation experiments demonstrated that Chlamydia trachomatis infection promoted the interaction of Rac with WAVE2 and Abi-1, but not with IRSp53. siRNA depletion of WAVE2 and Abi-1 abrogated chlamydia-induced actin recruitment and significantly reduced the uptake of the pathogen by the depleted cells. Chlamydia invasion also requires the Arp2/3 complex as demonstrated by its localization to the sites of chlamydial attachment and the reduced efficiency of chlamydial invasion in cells overexpressing the VCA domain of the neural Wiskott-Aldrich syndrome protein. Thus, C. trachomatis activates Rac and promotes its interaction with WAVE2 and Abi-1 to activate the Arp2/3 complex resulting in the induction of actin cytoskeletal rearrangements that are required for invasion.
The Rac-specific exchange factors Dock1 and Dock5 are dispensable for the establishment of the glomerular filtration barrier in vivo

PubMed Central

Laurin, Mélanie; Dumouchel, Annie; Fukui, Yoshinori; Côté, Jean-François

2013-01-01

Podocytes are specialized kidney cells that form the kidney filtration barrier through the connection of their foot processes. Nephrin and Neph family transmembrane molecules at the surface of podocytes interconnect to form a unique type of cell-cell junction, the slit diaphragm, which acts as a molecular sieve. The cytoplasmic tails of Nephrin and Neph mediate cytoskeletal rearrangement that contributes to the maintenance of the filtration barrier. Nephrin and Neph1 orthologs are essential to regulate cell-cell adhesion and Rac-dependent actin rearrangement during Drosophila myoblast fusion. We hypothesized here that molecules regulating myoblast fusion in Drosophila could contribute to signaling downstream of Nephrin and Neph1 in podocytes. We found that Nephrin engagement promoted recruitment of the Rac exchange factor Dock1 to the membrane. Furthermore, Nephrin overexpression led to lamellipodia formation that could be blocked by inhibiting Rac1 activity. We generated in vivo mouse models to investigate whether Dock1 and Dock5 contribute to the formation and maintenance of the kidney filtration barrier. Our results indicate that while Dock1 and Dock5 are expressed in podocytes, their functions are not essential for the development of the glomerular filtration barrier. Furthermore, mice lacking Dock1 were not protected from LPS-induced podocyte effacement. Our data suggest that Dock1 and Dock5 are not the important exchange factors regulating Rac activity during the establishment and maintenance of the glomerular barrier. PMID:24365888
Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress

PubMed Central

Wang, Hailong; Sun, Xiaoyan; Wang, Junjie; Monteiro, Paulo J.M.

2016-01-01

The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ). PMID:28773376
Postprandial triglyceride-rich lipoproteins promote invasion of human coronary artery smooth muscle cells in a fatty-acid manner through PI3k-Rac1-JNK signaling.

PubMed

Varela, Lourdes M; Bermúdez, Beatriz; Ortega-Gómez, Almudena; López, Sergio; Sánchez, Rosario; Villar, Jose; Anguille, Christelle; Muriana, Francisco J G; Roux, Pierre; Abia, Rocío

2014-06-01

The aim was to investigate the effect of postprandial triglyceride-rich lipoproteins (TRLs) with different fatty acid compositions on human coronary artery smooth muscle cell (hCASMC) invasion and to identify the molecular pathways involved. TRLs were isolated from the plasma of healthy volunteers after the ingestion of single meals enriched in MUFAs, saturated fatty acids (SFAs), or PUFAs. hCASMC invasion was analyzed using transwell chambers with Matrigel. TRLs-SFAs provoked the highest invasion, followed by TRLs-MUFAs and TRLs-PUFAs. Inhibition studies with Orlistat showed that invasion was dependent on the fatty acid composition of the TRLs. Fatty acids incorporated into the cell membranes strongly associated with cell invasion. Pull-down assays showed that TRLs-SFAs were able to increase Rac1 activity via inhibition of RhoA-dependent signaling. Chemical inhibition and siRNA studies showed that Rac1, PI3k, JNK, and MMP2 regulates TRL-SFA-induced hCASMC invasion. We demonstrate for the first time that TRLs induce hCASMCs invasion in a fatty acid dependent manner. This effect in TRLs-SFAs is mediated by the PI3k-Rac1-JNK, RhoA, and Rac1-MMP2 pathways. The ingestion of MUFA, compared to other dietary fatty acids such as SFA, could be considered as a nutritional strategy to reduce the atherosclerotic plaque formation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Novel Role for p21-activated Kinase 2 in Thrombin-induced Monocyte Migration*

PubMed Central

Gadepalli, Ravisekhar; Kotla, Sivareddy; Heckle, Mark R.; Verma, Shailendra K.; Singh, Nikhlesh K.; Rao, Gadiparthi N.

2013-01-01

To understand the role of thrombin in inflammation, we tested its effects on migration of THP-1 cells, a human monocytic cell line. Thrombin induced THP-1 cell migration in a dose-dependent manner. Thrombin induced tyrosine phosphorylation of Pyk2, Gab1, and p115 RhoGEF, leading to Rac1- and RhoA-dependent Pak2 activation. Downstream to Pyk2, Gab1 formed a complex with p115 RhoGEF involving their pleckstrin homology domains. Furthermore, inhibition or depletion of Pyk2, Gab1, p115 RhoGEF, Rac1, RhoA, or Pak2 levels substantially attenuated thrombin-induced THP-1 cell F-actin cytoskeletal remodeling and migration. Inhibition or depletion of PAR1 also blocked thrombin-induced activation of Pyk2, Gab1, p115 RhoGEF, Rac1, RhoA, and Pak2, resulting in diminished THP-1 cell F-actin cytoskeletal remodeling and migration. Similarly, depletion of Gα12 negated thrombin-induced Pyk2, Gab1, p115 RhoGEF, Rac1, RhoA, and Pak2 activation, leading to attenuation of THP-1 cell F-actin cytoskeletal remodeling and migration. These novel observations reveal that thrombin induces monocyte/macrophage migration via PAR1-Gα12-dependent Pyk2-mediated Gab1 and p115 RhoGEF interactions, leading to Rac1- and RhoA-targeted Pak2 activation. Thus, these findings provide mechanistic evidence for the role of thrombin and its receptor PAR1 in inflammation. PMID:24025335
Lineage-specific SoxR-mediated Regulation of an Endoribonuclease Protects Non-enteric Bacteria from Redox-active Compounds*

PubMed Central

Kim, Jisun; Park, Chulwoo; Imlay, James A.; Park, Woojun

2017-01-01

Bacteria use redox-sensitive transcription factors to coordinate responses to redox stress. The [2Fe-2S] cluster-containing transcription factor SoxR is particularly tuned to protect cells against redox-active compounds (RACs). In enteric bacteria, SoxR is paired with a second transcription factor, SoxS, that activates downstream effectors. However, SoxS is absent in non-enteric bacteria, raising questions as to how SoxR functions. Here, we first show that SoxR of Acinetobacter oleivorans displayed similar activation profiles in response to RACs as did its homolog from Escherichia coli but controlled a different set of target genes, including sinE, which encodes an endoribonuclease. Expression, gel mobility shift, and mutational analyses indicated that sinE is a direct target of SoxR. Redox potentials and permeability of RACs determined optimal sinE induction. Bioinformatics suggested that only a few γ- and β-proteobacteria might have SoxR-regulated sinE. Purified SinE, in the presence of Mg2+ ions, degrades rRNAs, thus inhibiting protein synthesis. Similarly, pretreatment of cells with RACs demonstrated a role for SinE in promoting persistence in the presence of antibiotics that inhibit protein synthesis. Our data improve our understanding of the physiology of soil microorganisms by suggesting that both non-enteric SoxR and its target SinE play protective roles in the presence of RACs and antibiotics. PMID:27895125
Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress.

PubMed

Wang, Hailong; Sun, Xiaoyan; Wang, Junjie; Monteiro, Paulo J M

2016-03-30

The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ).
Two distinct roles of mitogen-activated protein kinases in platelets and a novel Rac1-MAPK–dependent integrin outside-in retractile signaling pathway

PubMed Central

Flevaris, Panagiotis; Li, Zhenyu; Zhang, Guoying; Zheng, Yi; Liu, Junling

2009-01-01

Mitogen-activated protein kinases (MAPK), p38, and extracellular stimuli-responsive kinase (ERK), are acutely but transiently activated in platelets by platelet agonists, and the agonist-induced platelet MAPK activation is inhibited by ligand binding to the integrin αIIbβ3. Here we show that, although the activation of MAPK, as indicated by MAPK phosphorylation, is initially inhibited after ligand binding to integrin αIIbβ3, integrin outside-insignaling results in a late but sustained activation of MAPKs in platelets. Furthermore, we show that the early agonist-induced MAPK activation and the late integrin-mediated MAPK activation play distinct roles in different stages of platelet activation. Agonist-induced MAPK activation primarily plays an important role in stimulating secretion of platelet granules, while integrin-mediated MAPK activation is important in facilitating clot retraction. The stimulatory role of MAPK in clot retraction is mediated by stimulating myosin light chain (MLC) phosphorylation. Importantly, integrin-dependent MAPK activation, MAPK-dependent MLC phosphorylation, and clot retraction are inhibited by a Rac1 inhibitor and in Rac1 knockout platelets, indicating that integrin-induced activation of MAPK and MLC and subsequent clot retraction is Rac1-dependent. Thus, our results reveal 2 different activation mechanisms of MAPKs that are involved in distinct aspects of platelet function and a novel Rac1-MAPK–dependent cell retractile signaling pathway. PMID:18957688
PtdIns(3,4,5)P3 binding is necessary for WAVE2-induced formation of lamellipodia.

PubMed

Oikawa, Tsukasa; Yamaguchi, Hideki; Itoh, Toshiki; Kato, Masayoshi; Ijuin, Takeshi; Yamazaki, Daisuke; Suetsugu, Shiro; Takenawa, Tadaomi

2004-05-01

Polarized cell movement is triggered by the development of a PtdIns(3,4,5)P(3) gradient at the membrane, which is followed by rearrangement of the actin cytoskeleton. The WASP family verprolin homologous protein (WAVE) is essential for lamellipodium formation at the leading edge by activating the Arp2/3 complex downstream of Rac GTPase. Here, we report that WAVE2 binds to PtdIns(3,4,5)P(3) through its basic domain. The amino-terminal portion of WAVE2, which includes the PtdIns(3,4,5)P(3)-binding sequence, was localized at the leading edge of lamellipodia induced by an active form of Rac (RacDA) or by treatment with platelet-derived growth factor (PDGF). Production of PtdIns(3,4,5)P(3) at the cell membrane by myristoylated phosphatidylinositol-3-OH kinase (PI(3)K) is sufficient to recruit WAVE2 in the presence of dominant-negative Rac and latrunculin, demonstrating that PtdIns(3,4,5)P(3) alone is able to recruit WAVE2. Expression of a full-length mutant of WAVE2 that lacks the lipid-binding activity inhibited proper formation of lamellipodia induced by RacDA. These results suggest that one of the products of PI(3)K, PtdIns(3,4,5)P(3), recruits WAVE2 to the polarized membrane and that this recruitment is essential for lamellipodium formation at the leading edge.
CCL21 mediates CD4+ T-cell costimulation via a DOCK2/Rac-dependent pathway.

PubMed

Gollmer, Kathrin; Asperti-Boursin, François; Tanaka, Yoshihiko; Okkenhaug, Klaus; Vanhaesebroeck, Bart; Peterson, Jeffrey R; Fukui, Yoshinori; Donnadieu, Emmanuel; Stein, Jens V

2009-07-16

CD4(+) T cells use the chemokine receptor CCR7 to home to and migrate within lymphoid tissue, where T-cell activation takes place. Using primary T-cell receptor (TCR)-transgenic (tg) CD4(+) T cells, we explored the effect of CCR7 ligands, in particular CCL21, on T-cell activation. We found that the presence of CCL21 during early time points strongly increased in vitro T-cell proliferation after TCR stimulation, correlating with increased expression of early activation markers. CCL21 costimulation resulted in increased Ras- and Rac-GTP formation and enhanced phosphorylation of Akt, MEK, and ERK but not p38 or JNK. Kinase-dead PI3Kdelta(D910A/D910A) or PI3Kgamma-deficient TCR-tg CD4(+) T cells showed similar responsiveness to CCL21 costimulation as control CD4(+) T cells. Conversely, deficiency in the Rac guanine exchange factor DOCK2 significantly impaired CCL21-mediated costimulation in TCR-tg CD4(+) T cells, concomitant with impaired Rac- but not Ras-GTP formation. Using lymph node slices for live monitoring of T-cell behavior and activation, we found that G protein-coupled receptor signaling was required for early CD69 expression but not for Ca(2+) signaling. Our data suggest that the presence of CCL21 during early TCR signaling lowers the activation threshold through Ras- and Rac-dependent pathways leading to increased ERK phosphorylation.
Randomized controlled trial protocol: balance training with rhythmical cues to improve and maintain balance control in Parkinson's disease.

PubMed

Capato, Tamine Teixeira da Costa; Tornai, Juliana; Ávila, Patrícia; Barbosa, Egberto Reis; Piemonte, Maria Elisa Pimentel

2015-09-07

Postural instability is a particularly incapacitating disorder, whose loss of motor independence by Parkinson´s Disease (PD) patients marks a significant stage of disease onset. Evidence suggests that deficits in automatic motor control, sensory integration and attention are associated with the lack of balance in PD. Physiotherapy together with medication play an important role in the treatment of this state, although no consensus has been reached on the best treatment modality. The aim of this randomized controlled trial protocol is to evaluate the effects of balance training with rhythmical (BRT), which is a motor program to improve balance associated with rhythmical auditory cues (RACs). This study is ongoing in the stage 1. A total of 150 PD patients at H&Y stages II-III and asymptomatic for depression and dementia are enrolled in a single-blind randomized study. Randomization is achieved via a computer-generated random-sequence table. All patients should also present a fall history. They will be assigned into one of three groups, and their balance and gait will be assessed before and after 10 training sessions, and after 4 and 30 weeks subsequent to the end of the training. The BRT group will receive a motor program to improve balance associated with RACs, the MT group will perform motor training with the same aims as those in the BRT group but without RACs, and the control group (CG) will be trained only in orientations. The exercise program specific to balance is of 5 weeks' duration with two sessions per week, 45 min each, and consists of general physiotherapy exercises. Each session will be divided into five warm-up minutes-30 min for the main part and 10 min for the cool down. The training progresses and intensifies each week depending on the individual's performance. The subjects should be able to execute 10 repetitions of the exercise sequences correctly to progress to the next movement. This randomized study protocol will evaluate the effects of a motor program designed to improve balance associated with RACs, and will also assess whether balance training leads to activation of balance reactions at the appropriate time. We hypothesize that if this motor program is maintained long-term, it will prevent falls. Clinicaltrials.gov NCT02488265 ; Ethics Committee of the University of São Paulo Faculty of Medicine Clinics Hospital 1.102.464.
A MAPK-Driven Feedback Loop Suppresses Rac Activity to Promote RhoA-Driven Cancer Cell Invasion

PubMed Central

Hetmanski, Joseph H. R.; Zindy, Egor; Schwartz, Jean-Marc; Caswell, Patrick T.

2016-01-01

Cell migration in 3D microenvironments is fundamental to development, homeostasis and the pathobiology of diseases such as cancer. Rab-coupling protein (RCP) dependent co-trafficking of α5β1 and EGFR1 promotes cancer cell invasion into fibronectin (FN) containing extracellular matrix (ECM), by potentiating EGFR1 signalling at the front of invasive cells. This promotes a switch in RhoGTPase signalling to inhibit Rac1 and activate a RhoA-ROCK-Formin homology domain-containing 3 (FHOD3) pathway and generate filopodial actin-spike protrusions which drive invasion. To further understand the signalling network that drives RCP-driven invasive migration, we generated a Boolean logical model based on existing network pathways/models, where each node can be interrogated by computational simulation. The model predicted an unanticipated feedback loop, whereby Raf/MEK/ERK signalling maintains suppression of Rac1 by inhibiting the Rac-activating Sos1-Eps8-Abi1 complex, allowing RhoA activity to predominate in invasive protrusions. MEK inhibition was sufficient to promote lamellipodia formation and oppose filopodial actin-spike formation, and led to activation of Rac and inactivation of RhoA at the leading edge of cells moving in 3D matrix. Furthermore, MEK inhibition abrogated RCP/α5β1/EGFR1-driven invasive migration. However, upon knockdown of Eps8 (to suppress the Sos1-Abi1-Eps8 complex), MEK inhibition had no effect on RhoGTPase activity and did not oppose invasive migration, suggesting that MEK-ERK signalling suppresses the Rac-activating Sos1-Abi1-Eps8 complex to maintain RhoA activity and promote filopodial actin-spike formation and invasive migration. Our study highlights the predictive potential of mathematical modelling approaches, and demonstrates that a simple intervention (MEK-inhibition) could be of therapeutic benefit in preventing invasive migration and metastasis. PMID:27138333
Role of phospholipase Cgamma1 in cell spreading requires association with a beta-Pix/GIT1-containing complex, leading to activation of Cdc42 and Rac1.

PubMed

Jones, Neil P; Katan, Matilda

2007-08-01

The significance of multiprotein signaling complexes in cell motility is becoming increasingly important. We have previously shown that phospholipase Cgamma1 (PLCgamma1) is critical for integrin-mediated cell spreading and motility (N. Jones et al., J. Cell Sci. 118:2695-2706, 2005). In the current study we show that, on a basement membrane-type matrix, PLCgamma1 associates with the adaptor protein GIT1 and the Rac1/Cdc42 guanine exchange factor beta-Pix; GIT1 and beta-Pix form tight complexes independently of PLCgamma1. The association of PLCgamma1 with the complex requires both GIT1 and beta-Pix and the specific array region (gammaSA) of PLCgamma1. Mutations of PLCgamma1 within the gammaSA region reveal that association with this complex is essential for the phosphorylation of PLCgamma1 and the progression to an elongated morphology after integrin engagement. Short interfering RNA (siRNA) depletion of either beta-Pix or GIT1 inhibited cell spreading in a fashion similar to that seen with siRNA against PLCgamma1. Furthermore, siRNA depletion of PLCgamma1, beta-Pix, or GIT1 inhibited Cdc42 and Rac1 activation, while constitutively active forms of Cdc42 or Rac1, but not RhoA, were able to rescue the elongation of these cells. Signaling of the PLCgamma1/GIT1/beta-Pix complex to Cdc42/Rac1 was found to involve the activation of calpains, calcium-dependent proteases. Therefore, we propose that the association of PLCgamma1 with complexes containing GIT1 and beta-Pix is essential for its role in integrin-mediated cell spreading and motility. As a component of this complex, PLCgamma1 is also involved in the activation of Cdc42 and Rac1.
Antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells.

PubMed

Park, Sun Joo; Kim, Yong Tae; Jeon, You Jin

2012-04-01

Reactive oxygen species (ROS) generation is linked to dynamic actin cytoskeleton reorganization, which is involved in tumor cell motility and metastasis. Thus, inhibition of ROS generation and actin polymerization in tumor cells may represent an effective anticancer strategy. However, the molecular basis of this signaling pathway is currently unknown. Here, we show that the Ecklonia cava-derived antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells. Steady-state intracellular ROS levels were higher in malignant B16F10 cells than in parental, nonmetastatic B16F0 cells. Elevation of ROS by H(2)O(2) treatment increased migration and invasion ability of B16F0 cells to level similar to that of B16F10 cells, suggesting that intracellular ROS signaling mediates the prometastatic properties of B16 mouse melanoma cells. ROS levels and the cell migration and invasion ability of B16 melanoma cells correlated with Rac1 activation and WAVE2 expression. Overexpression of dominant negative Rac1 and depletion of WAVE2 by siRNA suppressed H(2)O(2)-induced cell invasion of B16F0 and B16F10 cells. Similarly, dieckol attenuates the ROS-mediated Rac1 activation and WAVE2 expression, resulting in decreased migration and invasion of B16 melanoma cells. In addition, we found that dieckol decreases association between WAVE2 and NADPH oxidase subunit p47(phox). Therefore, this finding suggests that WAVE2 acts to couple intracellular Rac1/ROS signaling to the invasive migration of B16 melanoma cells, which is inhibited by dieckol.
Antioxidant Dieckol Downregulates the Rac1/ROS Signaling Pathway and Inhibits Wiskott-Aldrich Syndrome Protein (WASP)-Family Verprolin-Homologous Protein 2 (WAVE2)-Mediated Invasive Migration of B16 Mouse Melanoma Cells

PubMed Central

Park, Sun Joo; Kim, Yong Tae; Jeon, You Jin

2012-01-01

Reactive oxygen species (ROS) generation is linked to dynamic actin cytoskeleton reorganization, which is involved in tumor cell motility and metastasis. Thus, inhibition of ROS generation and actin polymerization in tumor cells may represent an effective anticancer strategy. However, the molecular basis of this signaling pathway is currently unknown. Here, we show that the Ecklonia cava-derived antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells. Steady-state intracellular ROS levels were higher in malignant B16F10 cells than in parental, nonmetastatic B16F0 cells. Elevation of ROS by H2O2 treatment increased migration and invasion ability of B16F0 cells to level similar to that of B16F10 cells, suggesting that intracellular ROS signaling mediates the prometastatic properties of B16 mouse melanoma cells. ROS levels and the cell migration and invasion ability of B16 melanoma cells correlated with Rac1 activation and WAVE2 expression. Overexpression of dominant negative Rac1 and depletion of WAVE2 by siRNA suppressed H2O2-induced cell invasion of B16F0 and B16F10 cells. Similarly, dieckol attenuates the ROS-mediated Rac1 activation and WAVE2 expression, resulting in decreased migration and invasion of B16 melanoma cells. In addition, we found that dieckol decreases association between WAVE2 and NADPH oxidase subunit p47phox. Therefore, this finding suggests that WAVE2 acts to couple intracellular Rac1/ROS signaling to the invasive migration of B16 melanoma cells, which is inhibited by dieckol. PMID:22441674
Novel Activities of Select NSAID R-Enantiomers against Rac1 and Cdc42 GTPases

PubMed Central

Oprea, Tudor I.; Sklar, Larry A.; Agola, Jacob O.; Guo, Yuna; Silberberg, Melina; Roxby, Joshua; Vestling, Anna; Romero, Elsa; Surviladze, Zurab; Murray-Krezan, Cristina; Waller, Anna; Ursu, Oleg; Hudson, Laurie G.; Wandinger-Ness, Angela

2015-01-01

Rho family GTPases (including Rac, Rho and Cdc42) collectively control cell proliferation, adhesion and migration and are of interest as functional therapeutic targets in numerous epithelial cancers. Based on high throughput screening of the Prestwick Chemical Library® and cheminformatics we identified the R-enantiomers of two approved drugs (naproxen and ketorolac) as inhibitors of Rac1 and Cdc42. The corresponding S-enantiomers are considered the active component in racemic drug formulations, acting as non-steroidal anti-inflammatory drugs (NSAIDs) with selective activity against cyclooxygenases. Here, we show that the S-enantiomers of naproxen and ketorolac are inactive against the GTPases. Additionally, more than twenty other NSAIDs lacked inhibitory action against the GTPases, establishing the selectivity of the two identified NSAIDs. R-naproxen was first identified as a lead compound and tested in parallel with its S-enantiomer and the non-chiral 6-methoxy-naphthalene acetic acid (active metabolite of nabumetone, another NSAID) as a structural series. Cheminformatics-based substructure analyses—using the rotationally constrained carboxylate in R-naproxen—led to identification of racemic [R/S] ketorolac as a suitable FDA-approved candidate. Cell based measurement of GTPase activity (in animal and human cell lines) demonstrated that the R-enantiomers specifically inhibit epidermal growth factor stimulated Rac1 and Cdc42 activation. The GTPase inhibitory effects of the R-enantiomers in cells largely mimic those of established Rac1 (NSC23766) and Cdc42 (CID2950007/ML141) specific inhibitors. Docking predicts that rotational constraints position the carboxylate moieties of the R-enantiomers to preferentially coordinate the magnesium ion, thereby destabilizing nucleotide binding to Rac1 and Cdc42. The S-enantiomers can be docked but are less favorably positioned in proximity to the magnesium. R-naproxen and R-ketorolac have potential for rapid translation and efficacy in the treatment of several epithelial cancer types on account of established human toxicity profiles and novel activities against Rho-family GTPases. PMID:26558612
Solubility of (+/-)-ibuprofen and S (+)-ibuprofen in the presence of cosolvents and cyclodextrins.

PubMed

Nerurkar, Jayanti; Beach, J W; Park, M O; Jun, H W

2005-01-01

Aqueous solubility is an important parameter for the development of liquid formulations and in the determination of bioavailability of oral dosage forms. Ibuprofen (IB), a nonsteroidal anti-inflammatory drug, is a chiral molecule and is currently used clinically as a racemate (racIB). However, the S form of ibuprofen or S(+)-ibuprofen (SIB) is the biologically active isomer and is primarily responsible for the antiinflammatory activity. Phase solubility studies were carried out to compare the saturation solubilities of racIB and SIB in the presence of common pharmaceutical solvents such as glycerol, sorbitol solution, propylene glycol (PG), and polyethylene glycol (PEG 300) over the range of 20% to 80% v/v in aqueous based systems. The solubilities of the two compounds were also compared in the presence of cyclodextrins such as beta cyclodextrin (CD), hydroxypropyl beta cyclodextrin (HPCD), and beta cyclodextrin sulfobutyl ether sodium salt (CDSB) over the range of 5% to 25% w/v. Solubility determinations were carried at 25 degrees C and 37 degrees C. Cosolvents exponentially increased the solubility of both SIB and racIB, especially in the presence of PG and PEG 300. Glycerol was not very effective in increasing the aqueous solubilities of both compounds, whereas sorbitol solution had a minimal effect on their solubility. PG and PEG 300 increased the solubility of SIB by 400-fold and 1500-fold, respectively, whereas the rise in solubility for racIB was 193-fold and 700-fold, respectively, at 25 degrees C for the highest concentration of the cosolvents used (80% v/v). Of the two compounds studied, higher equilibrium solubilities were observed for SIB as compared with racIB. The derivatized cyclodextrins increased the aqueous solubility of racIB and SIB in a concentration-dependent manner giving AL type of phase diagrams. The phase solubility diagrams indicated the formation of soluble inclusion complexes between the drugs and HPCD and CDSB, which was of 1:1 stoichiometry. The addition of underivatized CD reduced the solubility of racIB and SIB via the formation of an insoluble complex. The S form formed more stable complexes with HPCD and CDSB as compared with raclB. The solubilization process is discussed in terms of solvent polarity and differential solid-state structure of raclB and SIB. The thermodynamic parameters for the solubilization process are presented.
The interaction of fiber, supplied by distillers dried grains with solubles, with an antimicrobial and a nutrient partitioning agent on nitrogen balance, water utilization, and energy digestibility in finishing pigs.

PubMed

Pilcher, C M; Arentson, R; Patience, J F

2015-03-01

The objective of this study was to determine if a higher-fiber diet alters the response of finishing pigs to an antimicrobial (tylosin phosphate [TP]) and a nutrient partitioning agent (ractopamine HCl [RAC]) in terms of N and water utilization and energy digestibility. Seventy-two gilts (initial BW = 107.4 ± 4.2 kg) were blocked by weight and allotted to 1 of 8 dietary treatments. Treatments were arranged as a 2 × 2 × 2 factorial: distillers dried grains with solubles (DDGS; 0 vs. 30%), RAC (0 mg of RAC/kg and 0.70% standardized ileal digestible [SID] Lys vs. 5 mg of RAC/kg and 0.95% SID Lys) and TP (0 vs. 44 mg of TP/kg). Pig was the experimental unit, with 9 replications per treatment. Pigs were housed in individual metabolism crates and fed treatment diets for 17 d. Feed was provided twice daily, as much as the pigs could consume within 1 h per meal, and water was provided to the pigs between feeding periods, ad libitum. Fecal and urine collection occurred on d 7 and 8 and on d 15 and 16, for sampling periods 1 and 2, respectively. Pigs fed the DDGS diets had reduced ADG ( < 0.001) and ADFI ( < 0.0001). The apparent total tract digestibility (ATTD) of N and GE were lower for the 30% DDGS diets than the 0% DDGS diets ( < 0.0001). Ractopamine improved ADG ( < 0.0001), G:F ( < 0.0001), and N retention ( < 0.001) and tended to increase daily water intake ( < 0.10). Pigs fed RAC had higher N intake and urinary excretion and lower N retention in Period 2 than in Period 1 ( < 0.05), indicating a decline in the response to RAC over time. Tylosin phosphate did not affect ADFI or G:F but did improve ATTD of N ( < 0.05). There was a tendency for a TP × DDGS interaction ( < 0.10) for ADG, where TP tended to increase ADG in pigs fed 0% DDGS diets ( < 0.10) but not in pigs fed 30% DDGS diets ( > 0.10). Pigs fed DDGS diets had higher N intake ( < 0.01) and higher fecal ( < 0.0001) and urinary ( < 0.01) N excretion with no difference in N retention (g/d). Overall, RAC increased N retention by 33% ( < 0.0001) and the response to RAC was similar in both corn-soybean meal-based and corn-soybean meal-DDGS-based diets. Tylosin phosphate tended to improve growth performance in pigs fed corn-soybean meal-based diets but not in diets containing 30% DDGS; however, this response was not explained by changes in N balance or in energy digestibility.
Enantioselective separation and online affinity chromatographic characterization of R,R- and S,S-fenoterol.

PubMed

Beigi, Farideh; Bertucci, Carlo; Zhu, Weizhong; Chakir, Khalid; Wainer, Irving W; Xiao, Rui-Ping; Abernethy, Darrell R

2006-11-01

rac-Fenoterol is a beta2-adrenoceptor agonist (beta2-AR) used in the treatment of asthma. It has two chiral centers and is marketed as a racemic mixture of R,R'- and S,S'-fenoterol (R-F and S-F). Here we report the separation of the R-F and S-F enantiomers and the evaluation of their binding to and activation of the beta2-AR. R-F and S-F were separated from the enantiomeric mixture by chiral chromatography and absolute configuration determined by circular dichroism. Beta2-AR binding was evaluated using frontal affinity chromatography with a stationary phase containing immobilized membranes from HEK-293 cells that express human beta2-AR and standard membrane binding studies using the same membranes. The effect of R-F and S-F on cardiomyocyte contractility was also investigated using freshly isolated adult rat cardiomyocytes. Chiral chromatography of rac-fenoterol yielded separated peaks with an enantioselectivity factor of 1.21. The less retained peak was assigned the absolute configuration of S-F and the more retained peak R-F. Frontal chromatography using membrane-bound beta2-AR as the stationary phase and rac-3H-fenoterol as a marker ligand showed that addition of increasing concentrations of R-F to the mobile phase produced concentration-dependent decreases in rac-3H-fenoterol retention, while similar addition of S-F produced no change in rac-3H-fenoterol retention. The calculated dissociation constant of R-F was 472 nM and the number of available binding sites 176 pmol/column, which was consistent with the results from the membrane binding study 460 +/- 55 nM (R-F) and 109,000 +/- 10,400 nM (S-F). In the cardiomyocytes, R-F increased maximum contractile response from (265 +/- 11.6)% to (306 +/- 11.8)% of resting cell length (P < 0.05) and reduced EC50 from -7.0 +/- 0.270 to -7.1 +/- 0.2 log[M] (P < 0.05), while S-F had no significant effect. Previous studies have shown that rac-fenoterol acts as an apparent beta2-AR/G(s) selective agonist and fully restores diminished beta2-AR contractile response in cardiomyocytes from failing hearts of spontaneously hypertensive rats (SHR). Here we report the separation of the enantiomers of rac-fenoterol and that R-F is the active component of rac-fenoterol. Further evaluation of R-F will determine if it has enhanced selectivity and specificity for beta2-AR/G(s) activation and if it can be used in the treatment of congestive heart failure. Published 2006 Wiley-Liss, Inc.
Involvement of the Rac1-IRSp53-Wave2-Arp2/3 Signaling Pathway in HIV-1 Gag Particle Release in CD4 T Cells.

PubMed

Thomas, Audrey; Mariani-Floderer, Charlotte; López-Huertas, Maria Rosa; Gros, Nathalie; Hamard-Péron, Elise; Favard, Cyril; Ohlmann, Theophile; Alcamí, José; Muriaux, Delphine

2015-08-01

During HIV-1 assembly, the Gag viral proteins are targeted and assemble at the inner leaflet of the cell plasma membrane. This process could modulate the cortical actin cytoskeleton, located underneath the plasma membrane, since actin dynamics are able to promote localized membrane reorganization. In addition, activated small Rho GTPases are known for regulating actin dynamics and membrane remodeling. Therefore, the modulation of such Rho GTPase activity and of F-actin by the Gag protein during virus particle formation was considered. Here, we studied the implication of the main Rac1, Cdc42, and RhoA small GTPases, and some of their effectors, in this process. The effect of small interfering RNA (siRNA)-mediated Rho GTPases and silencing of their effectors on Gag localization, Gag membrane attachment, and virus-like particle production was analyzed by immunofluorescence coupled to confocal microscopy, membrane flotation assays, and immunoblot assays, respectively. In parallel, the effect of Gag expression on the Rac1 activation level was monitored by G-LISA, and the intracellular F-actin content in T cells was monitored by flow cytometry and fluorescence microscopy. Our results revealed the involvement of activated Rac1 and of the IRSp53-Wave2-Arp2/3 signaling pathway in HIV-1 Gag membrane localization and particle release in T cells as well as a role for actin branching and polymerization, and this was solely dependent on the Gag viral protein. In conclusion, our results highlight a new role for the Rac1-IRSp53-Wave2-Arp2/3 signaling pathway in the late steps of HIV-1 replication in CD4 T lymphocytes. During HIV-1 assembly, the Gag proteins are targeted and assembled at the inner leaflet of the host cell plasma membrane. Gag interacts with specific membrane phospholipids that can also modulate the regulation of cortical actin cytoskeleton dynamics. Actin dynamics can promote localized membrane reorganization and thus can be involved in facilitating Gag assembly and particle formation. Activated small Rho GTPases and effectors are regulators of actin dynamics and membrane remodeling. We thus studied the effects of the Rac1, Cdc42, and RhoA GTPases and their specific effectors on HIV-1 Gag membrane localization and viral particle release in T cells. Our results show that activated Rac1 and the IRSp53-Wave2-Arp2/3 signaling pathway are involved in Gag plasma membrane localization and viral particle production. This work uncovers a role for cortical actin through the activation of Rac1 and the IRSp53/Wave2 signaling pathway in HIV-1 particle formation in CD4 T lymphocytes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Involvement of the Rac1-IRSp53-Wave2-Arp2/3 Signaling Pathway in HIV-1 Gag Particle Release in CD4 T Cells

PubMed Central

Thomas, Audrey; Mariani-Floderer, Charlotte; López-Huertas, Maria Rosa; Gros, Nathalie; Hamard-Péron, Elise; Favard, Cyril; Ohlmann, Theophile; Alcamí, José

2015-01-01

ABSTRACT During HIV-1 assembly, the Gag viral proteins are targeted and assemble at the inner leaflet of the cell plasma membrane. This process could modulate the cortical actin cytoskeleton, located underneath the plasma membrane, since actin dynamics are able to promote localized membrane reorganization. In addition, activated small Rho GTPases are known for regulating actin dynamics and membrane remodeling. Therefore, the modulation of such Rho GTPase activity and of F-actin by the Gag protein during virus particle formation was considered. Here, we studied the implication of the main Rac1, Cdc42, and RhoA small GTPases, and some of their effectors, in this process. The effect of small interfering RNA (siRNA)-mediated Rho GTPases and silencing of their effectors on Gag localization, Gag membrane attachment, and virus-like particle production was analyzed by immunofluorescence coupled to confocal microscopy, membrane flotation assays, and immunoblot assays, respectively. In parallel, the effect of Gag expression on the Rac1 activation level was monitored by G-LISA, and the intracellular F-actin content in T cells was monitored by flow cytometry and fluorescence microscopy. Our results revealed the involvement of activated Rac1 and of the IRSp53-Wave2-Arp2/3 signaling pathway in HIV-1 Gag membrane localization and particle release in T cells as well as a role for actin branching and polymerization, and this was solely dependent on the Gag viral protein. In conclusion, our results highlight a new role for the Rac1-IRSp53-Wave2-Arp2/3 signaling pathway in the late steps of HIV-1 replication in CD4 T lymphocytes. IMPORTANCE During HIV-1 assembly, the Gag proteins are targeted and assembled at the inner leaflet of the host cell plasma membrane. Gag interacts with specific membrane phospholipids that can also modulate the regulation of cortical actin cytoskeleton dynamics. Actin dynamics can promote localized membrane reorganization and thus can be involved in facilitating Gag assembly and particle formation. Activated small Rho GTPases and effectors are regulators of actin dynamics and membrane remodeling. We thus studied the effects of the Rac1, Cdc42, and RhoA GTPases and their specific effectors on HIV-1 Gag membrane localization and viral particle release in T cells. Our results show that activated Rac1 and the IRSp53-Wave2-Arp2/3 signaling pathway are involved in Gag plasma membrane localization and viral particle production. This work uncovers a role for cortical actin through the activation of Rac1 and the IRSp53/Wave2 signaling pathway in HIV-1 particle formation in CD4 T lymphocytes. PMID:26018170
PHP14 regulates hepatic stellate cells migration in liver fibrosis via mediating TGF-β1 signaling to PI3Kγ/AKT/Rac1 pathway.

PubMed

Xu, Anjian; Li, Yanmeng; Zhao, Wenshan; Hou, Fei; Li, Xiaojin; Sun, Lan; Chen, Wei; Yang, Aiting; Wu, Shanna; Zhang, Bei; Yao, Jingyi; Wang, Huan; Huang, Jian

2018-02-01

Hepatic fibrosis is characterized by the activation of hepatic stellate cells (HSCs). Migration of the activated HSCs to the site of injury is one of the key characteristics during the wound healing process. We have previously demonstrated that 14 kDa phosphohistidine phosphatase (PHP14) is involved in migration and lamellipodia formation of HSCs. However, the role of PHP14 in liver fibrosis remains unknown. In this study, we first assessed PHP14 expression and distribution in liver fibrotic tissues using western blot, immunohistochemistry, and double immunofluorescence staining. Next, we investigated the role of PHP14 in liver fibrosis and, more specifically, the migration of HSCs by Transwell assay and 3D collagen matrices assay. Finally, we explored the possible molecular mechanisms of the effects of PHP14 on these processes. Our results show that the PHP14 expression is up-regulated in fibrotic liver and mainly in HSCs. Importantly, TGF-β1 can induce PHP14 expression in HSCs accompanied with the activation of HSCs. Consistent with the previous study, PHP14 promotes HSCs migration, especially, promotes 3D floating collagen matrices contraction but inhibits stressed-released matrices contraction. Mechanistically, the PI3Kγ/AKT/Rac1 pathway is involved in migration regulated by PHP14. Moreover, PHP14 specifically mediates the TGF-β1 signaling to PI3Kγ/AKT pathway and regulates HSC migration, and thus participates in liver fibrosis. Our study identified the role of PHP14 in liver fibrosis, particularly HSC migration, and suggested a novel mediator of transducting TGF-β1 signaling to PI3Kγ/AKT/Rac1 pathway. PHP14 is up-regulated in fibrotic liver and activated hepatic stellate cells. The expression of PHP14 is induced by TGF-β1. The migration of hepatic stellate cells is regulated by PHP14. PHP14 is a mediator of TGF-β1 signaling to PI3Kγ/AKT/Rac1 pathway in hepatic stellate cells.
44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop their radiological emergency plans, to review the plans, and to observe exercises to evaluate the plans. Under subparts A and B of this part, these technical assistance activities are extended to the licensee...
44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop their radiological emergency plans, to review the plans, and to observe exercises to evaluate the plans. Under subparts A and B of this part, these technical assistance activities are extended to the licensee...
Aggression, behavior and peripheral amine concentrations in relation to ractopamine feeding, sex, and social rank of finishing pigs

USDA-ARS?s Scientific Manuscript database

The effects of the widely used feed additive ractopamine (RAC) on behavioral and physiological responses in finishing pigs are limited. Aggression is of concern for its potential to impair pig’s productivity and well-being; thus its relation with feeding of RAC, an adrenoreceptor agonist, warrants f...
75 FR 35832 - Notice of Public Tour and Meeting, Twin Falls District Resource Advisory Council, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-23

... of Public Tour and Meeting, Twin Falls District Resource Advisory Council, Idaho AGENCY: Bureau of... Land Management (BLM) Twin Falls District Resource Advisory Council (RAC) will attend a two-day tour and meeting as indicated below. DATES: July 20-21, 2010. The Twin Falls District RAC members will meet...
78 FR 69706 - Notice of Public Meeting for the Southeast Oregon Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-20

... and Tuesday, January 13 and 14, 2014. The exact meeting time, agenda, and location will be announced... accommodate necessary business and all who seek to be heard regarding matters before the Southeast Oregon RAC. ADDRESSES: The exact meeting time, agenda, and location will be announced online at www.blm.gov/or/rac...
78 FR 64236 - Notice of Public Meeting for the John Day; Snake Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-28

...] Notice of Public Meeting for the John Day; Snake Resource Advisory Council AGENCY: Bureau of Land... Interior, Bureau of Land Management (BLM), the John Day--Snake Resource Advisory Council (RAC) will meet as indicated below: DATES: The John Day--Snake RAC will hold a public meeting Thursday and Friday, November 14...
78 FR 76175 - Notice of Public Meeting for the John Day-Snake Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-16

...] Notice of Public Meeting for the John Day-Snake Resource Advisory Council AGENCY: Bureau of Land... Interior, Bureau of Land Management (BLM), the John Day-Snake Resource Advisory Council (RAC) will meet as indicated below: DATES: The John Day-Snake RAC will hold a public meeting Thursday and Friday, January 9 and...
78 FR 62657 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-22

... indicated below. DATES: The Southwest Colorado RAC meeting will be held on November 15, 2013, in Dolores, Colorado. ADDRESSES: The Southwest Colorado RAC meeting will be held November 15, 2013, at the Dolores Public Lands Center, 29211 Highway 184, Dolores, CO 81323. The meeting will begin at 9 a.m. and adjourn...
Development of the National Institutes of Health Guidelines for Recombinant DNA Research.

PubMed Central

Talbot, B

1983-01-01

Recombinant DNA is a technique of major importance in basic biomedical research and, increasingly, in industrial applications. Although the risks of this research remain hypothetical, scientists working in the field have spearheaded discussions of safety. The original National Institutes of Health (NIH) Guidelines for Recombinant DNA Research were issued in June 1976. They assigned each type of recombinant DNA experiment a specific level of "physical containment" and of "biological containment." Responsibility for overseeing the application of the guidelines belongs to the NIH Recombinant DNA Advisory Committee (RAC)--composed of scientists and laymen, including non-voting representatives from many Federal agencies--and local institutional biosafety committees at each university where recombinant DNA research is conducted. The NIH guidelines were subsequently adopted by other Federal agencies, but congressional proposals aimed at extending the guidelines to private industry did not result in national legislation. Some States and localities regulate recombinant DNA research, however, and many private companies have voluntarily submitted information on their recombinant DNA work for RAC and NIH approval. The NIH guidelines underwent a major revision in December 1978 and have been revised approximately every 3 months since then. NIH supports experiments to assess recombinant DNA risks and publishes and updates a plan for a risk assessment program. PMID:6611823
Environmental monitoring and assessment of heavy metals in surface sediments at Coleroon River Estuary in Tamil Nadu, India.

PubMed

Venkatramanan, S; Chung, S Y; Ramkumar, T; Selvam, S

2015-08-01

The combined studies on grain size distribution, organic matter contents of sediments, sequential extraction and bulk concentration of heavy metals, statistical analysis, and ecological risk assessments were carried out to investigate the contamination sources and ecological risks of surface sediments at Coleroon River Estuary in Tamil Nadu, India. The sequential extraction of metals showed that a larger portion of the metals was associated with the residual phase and also in other fractions. The low concentrations of heavy metals were found in exchangeable and carbonate bounds (bioavailable phases). It revealed that sediments of Coleroon River Estuary were relatively unpolluted and were influenced mainly by natural sources. The observed order of bulk concentrations of heavy metals in the sediments was as follows: Fe > Mn > Zn > Cu > Pb > Cr > Ni > Co. Factor analyses represented that the enrichment of heavy metals was mostly resulted from lithogenic origins associated with anthropogenic sources. These sources were reconfirmed by cluster analysis. Risk assessment code (RAC) suggested that all metals were not harmful in monsoon season. However, Fe was in medium risk, and Mn and Cu were in low risk in summer. According to pollution load index (PLI) of sediments, all heavy metals were toxic. Cu might be related with adverse biological effects on the basis of sediment quality guidelines (SQG) in both seasons. These integrated approaches were very useful to identify the contamination sources and ecological risks of sediments in estuarine environment. It is expected that this research can give a useful information for the remediation of heavy metals in sediments.
Occurrence and fractionation of Cr along the Loushan River affected by a chromium slag heap in East China.

PubMed

Chen, Youyuan; Dong, Bingbing; Xin, Jia

2017-06-01

This study investigated the chromium (Cr) occurrence and distribution along the Loushan River adjacent to a chromium slag heap. The speciation and chemical fractionation of Cr in different environmental media were determined. The potential ecological risks for the surrounding environment were assessed on the basis of both potential ecological risk index (RI) and risk assessment code (RAC). The results show that the surface soil experienced severe Cr contamination with Cr(T) and Cr(VI) values of 3220 ± 6266 and 64 ± 94 mg/kg, respectively, even though the chromium slag heap had already been removed. The chromium slag enhanced the Cr concentration level in the surface soil, water, and sediment samples more than the background level to different extents, which indicates that Cr released from the chromium slag actually affects the surrounding environment. The spatial distribution variety of Cr implies that their transport might have been affected by soil leaking, atmospheric transport, and fluvial hydraulics. The chemical fractionation results demonstrate that the residual fraction was the dominant form, accounting for 54.6 and 66.1% Cr(T) in surface soil and sediment samples, respectively. The content of bioavailable exchangeable Cr fraction correlated with the organic matter (OM), cation exchange capacity (CEC), and pH value. The ecological risk assessment suggests no considerable ecological risk toward the biota despite a relatively high Cr(T) level. Nevertheless, attention should be paid to the potential long-term risks owing to the slow release of oxidizable and residual fractions.
[Speciation Distribution and Risk Assessment of Heavy Metals in Typical Material Roof Dusts].

PubMed

Li, Dun-zhu; Guan, Yun-tao; Liu, An; Li, Si-yuan

2015-09-01

With the modified BCR sequential extraction procedure, the chemical speciation and risk for 10 heavy metals (Ba, Co, Cr, Cu, Mn, Ni, Pb, Sb, Sr and Zn) in roof dusts were investigated. The subjects of this study were collected from four typical material paved roofs (i. e., ceramic tile, concrete, metal and asphalt) in southeast China. The results indicated that the average contents of heavy metals in roof dust significantly exceeded road dust. The analysis of chemical fraction showed that the acid soluble/exchangeable fraction of Zn was much higher than other elements, the existence of Pb and Cu was mainly in oxidization fraction, while other heavy metals dominated by the residual fraction. The mobility sequence percentages for all roof dust samples decreased in the order of Pb > Zn > Cu >Mn > Co >Sr > Sb > Ni > Ba > Cr, and it should be noted that Pb, Zn, Cu, Mn and Co all have more than 50% proportion in mobility sequence. Based on environmental risk assessment, the highest values of contamination factors (Cf) and risk assessment code (RAC) consistently was observed in Zn, which indicated that Zn had relatively high ecological risk. Health risk assessment showed that the non-carcinogenic hazard indexes (HI) of heavy metals decreased in the order of Pb > Cr > Sb > Zn > Mn > Cu > Ba > Ni > Co > Sr, the HI of heavy metals for adults were lower than safe value while the HI of Pb for children was higher than safe value, suggesting that they will not harm the adult's health except Pb for children. The carcinogenic risk for Cr, Co and Ni were all below the threshold values, which indicated that there was no carcinogenic risk.
CDKL5, a protein associated with rett syndrome, regulates neuronal morphogenesis via Rac1 signaling.

PubMed

Chen, Qian; Zhu, Yong-Chuan; Yu, Jing; Miao, Sheng; Zheng, Jing; Xu, Li; Zhou, Yang; Li, Dan; Zhang, Chi; Tao, Jiong; Xiong, Zhi-Qi

2010-09-22

Mutations in cyclin-dependent kinase-like 5 (CDKL5), also known as serine/threonine kinase 9 (STK9), have been identified in patients with Rett syndrome (RTT) and X-linked infantile spasm. However, the function of CDKL5 in the brain remains unknown. Here, we report that CDKL5 is a critical regulator of neuronal morphogenesis. We identified a neuron-specific splicing variant of CDKL5 whose expression was markedly induced during postnatal development of the rat brain. Downregulating CDKL5 by RNA interference (RNAi) in cultured cortical neurons inhibited neurite growth and dendritic arborization, whereas overexpressing CDKL5 had opposite effects. Furthermore, knocking down CDKL5 in the rat brain by in utero electroporation resulted in delayed neuronal migration, and severely impaired dendritic arborization. In contrast to its proposed function in the nucleus, we found that CDKL5 regulated dendrite development through a cytoplasmic mechanism. In fibroblasts and in neurons, CDKL5 colocalized and formed a protein complex with Rac1, a critical regulator of actin remodeling and neuronal morphogenesis. Overexpression of Rac1 prevented the inhibition of dendrite growth caused by CDKL5 knockdown, and the growth-promoting effect of ectopically expressed CDKL5 on dendrites was abolished by coexpressing a dominant-negative form of Rac1. Moreover, CDKL5 was required for brain-derived neurotrophic factor (BDNF)-induced activation of Rac1. Together, these results demonstrate a critical role of CDKL5 in neuronal morphogenesis and identify a Rho GTPase signaling pathway which may contribute to CDKL5-related disorders.
Pigment Epithelium-Derived Factor Blocks Tumor Extravasation by Suppressing Amoeboid Morphology and Mesenchymal Proteolysis12

PubMed Central

Ladhani, Omar; Sánchez-Martinez, Cristina; Orgaz, Jose L; Jimenez, Benilde; Volpert, Olga V

2011-01-01

Metastatic melanoma cells are highly adaptable to their in vivo microenvironment and can switch between protease-dependent mesenchymal and protease-independent amoeboid invasion to facilitate metastasis. Such adaptability can be visualized in vitro, when cells are cultured in conditions that recapitulate three-dimensional microenvironments. Using thick collagen layers in cell culture and in vivo extravasation assays, we found that pigment epithelium-derived factor (PEDF) suppressed lung extravasation of aggressive melanoma by coordinated regulation of cell shape and proteolysis. In cells grown on a thick collagen bed, PEDF overexpression and exogenous PEDF blocked the rapidly invasive, rounded morphology, and promoted an elongated, mesenchymal-like phenotype associated with reduced invasion. These changes in cell shape depended on decreased RhoA and increased Rac1 activation and were mediated by the up-regulation of Rac1-GEF, DOCK3 and down-regulation of Rac1-GAP, ARHGAP22. Surprisingly, we found that PEDF overexpression also blocked the trafficking of membrane-tethered, MT1-MMP to the cell surface through RhoA inhibition and Rac1 activation. In vivo, knockdown of Rac1 and DOCK3 or overexpression of MT1-MMP was sufficient to reverse the inhibitory effect of PEDF on extravasation. Using functional studies, we demonstrated that PEDF suppressed the rounded morphology and MT1-MMP surface localization through its antiangiongenic, 34-mer epitope and the recently identified PEDF receptor candidate, PNPLA2. Our findings unveil the coordinated regulation of cell shape and proteolysis and identify an unknown mechanism for PEDF's antimetastatic activity. PMID:21750657
RIT1 controls actin dynamics via complex formation with RAC1/CDC42 and PAK1.

PubMed

Meyer Zum Büschenfelde, Uta; Brandenstein, Laura Isabel; von Elsner, Leonie; Flato, Kristina; Holling, Tess; Zenker, Martin; Rosenberger, Georg; Kutsche, Kerstin

2018-05-01

RIT1 belongs to the RAS family of small GTPases. Germline and somatic RIT1 mutations have been identified in Noonan syndrome (NS) and cancer, respectively. By using heterologous expression systems and purified recombinant proteins, we identified the p21-activated kinase 1 (PAK1) as novel direct effector of RIT1. We found RIT1 also to directly interact with the RHO GTPases CDC42 and RAC1, both of which are crucial regulators of actin dynamics upstream of PAK1. These interactions are independent of the guanine nucleotide bound to RIT1. Disease-causing RIT1 mutations enhance protein-protein interaction between RIT1 and PAK1, CDC42 or RAC1 and uncouple complex formation from serum and growth factors. We show that the RIT1-PAK1 complex regulates cytoskeletal rearrangements as expression of wild-type RIT1 and its mutant forms resulted in dissolution of stress fibers and reduction of mature paxillin-containing focal adhesions in COS7 cells. This effect was prevented by co-expression of RIT1 with dominant-negative CDC42 or RAC1 and kinase-dead PAK1. By using a transwell migration assay, we show that RIT1 wildtype and the disease-associated variants enhance cell motility. Our work demonstrates a new function for RIT1 in controlling actin dynamics via acting in a signaling module containing PAK1 and RAC1/CDC42, and highlights defects in cell adhesion and migration as possible disease mechanism underlying NS.
RIT1 controls actin dynamics via complex formation with RAC1/CDC42 and PAK1

PubMed Central

von Elsner, Leonie; Flato, Kristina; Holling, Tess; Zenker, Martin; Rosenberger, Georg

2018-01-01

RIT1 belongs to the RAS family of small GTPases. Germline and somatic RIT1 mutations have been identified in Noonan syndrome (NS) and cancer, respectively. By using heterologous expression systems and purified recombinant proteins, we identified the p21-activated kinase 1 (PAK1) as novel direct effector of RIT1. We found RIT1 also to directly interact with the RHO GTPases CDC42 and RAC1, both of which are crucial regulators of actin dynamics upstream of PAK1. These interactions are independent of the guanine nucleotide bound to RIT1. Disease-causing RIT1 mutations enhance protein-protein interaction between RIT1 and PAK1, CDC42 or RAC1 and uncouple complex formation from serum and growth factors. We show that the RIT1-PAK1 complex regulates cytoskeletal rearrangements as expression of wild-type RIT1 and its mutant forms resulted in dissolution of stress fibers and reduction of mature paxillin-containing focal adhesions in COS7 cells. This effect was prevented by co-expression of RIT1 with dominant-negative CDC42 or RAC1 and kinase-dead PAK1. By using a transwell migration assay, we show that RIT1 wildtype and the disease-associated variants enhance cell motility. Our work demonstrates a new function for RIT1 in controlling actin dynamics via acting in a signaling module containing PAK1 and RAC1/CDC42, and highlights defects in cell adhesion and migration as possible disease mechanism underlying NS. PMID:29734338
P311 Accelerates Skin Wound Reepithelialization by Promoting Epidermal Stem Cell Migration Through RhoA and Rac1 Activation.

PubMed

Yao, Zhihui; Li, Haisheng; He, Weifeng; Yang, Sisi; Zhang, Xiaorong; Zhan, Rixing; Xu, Rui; Tan, Jianglin; Zhou, Junyi; Wu, Jun; Luo, Gaoxing

2017-03-15

P311 is a newly discovered functional gene, and it has been proved to play a key role in blood pressure homeostasis, glioblastoma invasion, renal fibrosis, hypertrophic scar formation, and others. In this study, for the first time, we found that P311 could enhance reepithelialization during wound healing via promoting epidermal stem cell (EpSC) migration through Rho GTPases. P311 expression was highly increased in neo-epidermal cells during human and mouse skin wound healing, and P311was co-localized with 5-bromo-2'-deoxyuridine positive label-retaining cells in a mouse superficial second-degree burn wound model. Furthermore, transfection of human EpSCs with adenovirus encoding P311 significantly accelerated the cell migration in vitro. Moreover, highly expressed P311 could enhance the activities of the Rho GTPases (RhoA, Rac1, and Cdc42) in cultured human EpSCs. P311-knockout mouse EpSCs showed dramatically decreased cell migration and activities of Rho GTPases (RhoA, Rac1, and Cdc42). Besides, both the RhoA-specific inhibitor and the Rac1 inhibitor, not the Cdc42 inhibitor, could significantly suppress P311-induced human EpSC migration. In vivo, the reepithelialization was markedly impaired during wound healing after P311 was knocked out. Together, our results suggested that P311 could accelerate skin wound reepithelialization by promoting the migration of EpSCs through RhoA and Rac1 activation. P311 could serve as a novel target for regulation of EpSC migration during cutaneous wound healing.
Pigment epithelium-derived factor blocks tumor extravasation by suppressing amoeboid morphology and mesenchymal proteolysis.

PubMed

Ladhani, Omar; Sánchez-Martinez, Cristina; Orgaz, Jose L; Jimenez, Benilde; Volpert, Olga V

2011-07-01

Metastatic melanoma cells are highly adaptable to their in vivo microenvironment and can switch between protease-dependent mesenchymal and protease-independent amoeboid invasion to facilitate metastasis. Such adaptability can be visualized in vitro, when cells are cultured in conditions that recapitulate three-dimensional microenvironments. Using thick collagen layers in cell culture and in vivo extravasation assays, we found that pigment epithelium-derived factor (PEDF) suppressed lung extravasation of aggressive melanoma by coordinated regulation of cell shape and proteolysis. In cells grown on a thick collagen bed, PEDF overexpression and exogenous PEDF blocked the rapidly invasive, rounded morphology, and promoted an elongated, mesenchymal-like phenotype associated with reduced invasion. These changes in cell shape depended on decreased RhoA and increased Rac1 activation and were mediated by the up-regulation of Rac1-GEF, DOCK3 and down-regulation of Rac1-GAP, ARHGAP22. Surprisingly, we found that PEDF overexpression also blocked the trafficking of membrane-tethered, MT1-MMP to the cell surface through RhoA inhibition and Rac1 activation. In vivo, knockdown of Rac1 and DOCK3 or overexpression of MT1-MMP was sufficient to reverse the inhibitory effect of PEDF on extravasation. Using functional studies, we demonstrated that PEDF suppressed the rounded morphology and MT1-MMP surface localization through its antiangiongenic, 34-mer epitope and the recently identified PEDF receptor candidate, PNPLA2. Our findings unveil the coordinated regulation of cell shape and proteolysis and identify an unknown mechanism for PEDF's antimetastatic activity.

Some links on this page may take you to non-federal websites. Their policies may differ from this site.