The Use of a Dexamethasone-inducible System to Synchronize Xa21 Expression to Study Rice Immunity.

PubMed

Caddell, Daniel F; Wei, Tong; Park, Chang-Jin; Ronald, Pamela C

2015-05-05

Inducible gene expression systems offer researchers the opportunity to synchronize target gene expression at particular developmental stages and in particular tissues. The glucocorticoid receptor (GR), a vertebrate steroid receptor, has been well adopted for this purpose in plants. To generate steroid-inducible plants, a construct of GAL4-binding domain-VP16 activation domain-GR fusion (GVG) with the target gene under the control of upstream activation sequence (UAS) has been developed and extensively used in plant research. Immune receptors perceive conserved molecular patterns secreted by pathogens and initiate robust immune responses. The rice immune receptor, XA21 , recognizes a molecular pattern highly conserved in all sequenced genomes of Xanthomonas , and confers robust resistance to X. oryzae pv. oryzae ( Xoo ). However, identifying genes downstream of XA21 has been hindered because of the restrained lesion and thus limited defense response region in the plants expressing Xa21 . Inducible expression allows for a synchronized immune response across a large amount of rice tissue, well suited for studying XA21-mediated immunity by genome-wide approaches such as transcriptomics and proteomics. In this protocol, we describe the use of this GVG system to synchronize Xa21 expression.

The Use of a Dexamethasone-inducible System to Synchronize Xa21 Expression to Study Rice Immunity

PubMed Central

Caddell, Daniel F.; Wei, Tong; Park, Chang-Jin; Ronald, Pamela C.

2016-01-01

Inducible gene expression systems offer researchers the opportunity to synchronize target gene expression at particular developmental stages and in particular tissues. The glucocorticoid receptor (GR), a vertebrate steroid receptor, has been well adopted for this purpose in plants. To generate steroid-inducible plants, a construct of GAL4-binding domain-VP16 activation domain-GR fusion (GVG) with the target gene under the control of upstream activation sequence (UAS) has been developed and extensively used in plant research. Immune receptors perceive conserved molecular patterns secreted by pathogens and initiate robust immune responses. The rice immune receptor, XA21, recognizes a molecular pattern highly conserved in all sequenced genomes of Xanthomonas, and confers robust resistance to X. oryzae pv. oryzae (Xoo). However, identifying genes downstream of XA21 has been hindered because of the restrained lesion and thus limited defense response region in the plants expressing Xa21. Inducible expression allows for a synchronized immune response across a large amount of rice tissue, well suited for studying XA21-mediated immunity by genome-wide approaches such as transcriptomics and proteomics. In this protocol, we describe the use of this GVG system to synchronize Xa21 expression. PMID:27525297

Promoter variants of Xa23 alleles affect bacterial blight resistance and evolutionary pattern

PubMed Central

Xu, Feifei; Tang, Yongchao; Gao, Ying

2017-01-01

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is the most important bacterial disease in rice (Oryza sativa L.). Our previous studies have revealed that the bacterial blight resistance gene Xa23 from wild rice O. rufipogon Griff. confers the broadest-spectrum resistance against all the naturally occurring Xoo races. As a novel executor R gene, Xa23 is transcriptionally activated by the bacterial avirulence (Avr) protein AvrXa23 via binding to a 28-bp DNA element (EBEAvrXa23) in the promoter region. So far, the evolutionary mechanism of Xa23 remains to be illustrated. Here, a rice germplasm collection of 97 accessions, including 29 rice cultivars (indica and japonica) and 68 wild relatives, was used to analyze the evolution, phylogeographic relationship and association of Xa23 alleles with bacterial blight resistance. All the ~ 473 bp DNA fragments consisting of promoter and coding regions of Xa23 alleles in the germplasm accessions were PCR-amplified and sequenced, and nine single nucleotide polymorphisms (SNPs) were detected in the promoter regions (~131 bp sequence upstream from the start codon ATG) of Xa23/xa23 alleles while only two SNPs were found in the coding regions. The SNPs in the promoter regions formed 5 haplotypes (Pro-A, B, C, D, E) which showed no significant difference in geographic distribution among these 97 rice accessions. However, haplotype association analysis indicated that Pro-A is the most favored haplotype for bacterial blight resistance. Moreover, SNP changes among the 5 haplotypes mostly located in the EBE/ebe regions (EBEAvrXa23 and corresponding ebes located in promoters of xa23 alleles), confirming that the EBE region is the key factor to confer bacterial blight resistance by altering gene expression. Polymorphism analysis and neutral test implied that Xa23 had undergone a bottleneck effect, and selection process of Xa23 was not detected in cultivated rice. In addition, the Xa23 coding region was found highly

Promoter variants of Xa23 alleles affect bacterial blight resistance and evolutionary pattern.

PubMed

Cui, Hua; Wang, Chunlian; Qin, Tengfei; Xu, Feifei; Tang, Yongchao; Gao, Ying; Zhao, Kaijun

2017-01-01

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is the most important bacterial disease in rice (Oryza sativa L.). Our previous studies have revealed that the bacterial blight resistance gene Xa23 from wild rice O. rufipogon Griff. confers the broadest-spectrum resistance against all the naturally occurring Xoo races. As a novel executor R gene, Xa23 is transcriptionally activated by the bacterial avirulence (Avr) protein AvrXa23 via binding to a 28-bp DNA element (EBEAvrXa23) in the promoter region. So far, the evolutionary mechanism of Xa23 remains to be illustrated. Here, a rice germplasm collection of 97 accessions, including 29 rice cultivars (indica and japonica) and 68 wild relatives, was used to analyze the evolution, phylogeographic relationship and association of Xa23 alleles with bacterial blight resistance. All the ~ 473 bp DNA fragments consisting of promoter and coding regions of Xa23 alleles in the germplasm accessions were PCR-amplified and sequenced, and nine single nucleotide polymorphisms (SNPs) were detected in the promoter regions (~131 bp sequence upstream from the start codon ATG) of Xa23/xa23 alleles while only two SNPs were found in the coding regions. The SNPs in the promoter regions formed 5 haplotypes (Pro-A, B, C, D, E) which showed no significant difference in geographic distribution among these 97 rice accessions. However, haplotype association analysis indicated that Pro-A is the most favored haplotype for bacterial blight resistance. Moreover, SNP changes among the 5 haplotypes mostly located in the EBE/ebe regions (EBEAvrXa23 and corresponding ebes located in promoters of xa23 alleles), confirming that the EBE region is the key factor to confer bacterial blight resistance by altering gene expression. Polymorphism analysis and neutral test implied that Xa23 had undergone a bottleneck effect, and selection process of Xa23 was not detected in cultivated rice. In addition, the Xa23 coding region was found highly

The Xanthomonas oryzae pv. oryzae PhoPQ Two-Component System Is Required for AvrXA21 Activity, hrpG Expression, and Virulence▿ †

PubMed Central

Lee, Sang-Won; Jeong, Kyu-Sik; Han, Sang-Wook; Lee, Seung-Eun; Phee, Bong-Kwan; Hahn, Tae-Ryong; Ronald, Pamela

2008-01-01

The rice pathogen recognition receptor, XA21, confers resistance to Xanthomonas oryzae pv. oryzae strains producing the type one system-secreted molecule, AvrXA21. X. oryzae pv. oryzae requires a regulatory two-component system (TCS) called RaxRH to regulate expression of eight rax (required for AvrXA21 activity) genes and to sense population cell density. To identify other key components in this critical regulatory circuit, we assayed proteins expressed in a raxR gene knockout strain. This survey led to the identification of the phoP gene encoding a response regulator that is up-regulated in the raxR knockout strain. Next we generated a phoP knockout strain and found it to be impaired in X. oryzae pv. oryzae virulence and no longer able to activate the response regulator HrpG (hypersensitive reaction and pathogenicity G) in response to low levels of Ca2+. The impaired virulence of the phoP knockout strain can be partially complemented by constitutive expression of hrpG, indicating that PhoP controls a key aspect of X. oryzae pv. oryzae virulence through regulation of hrpG. A gene encoding the cognate putative histidine protein kinase, phoQ, was also isolated. Growth curve analysis revealed that AvrXA21 activity is impaired in a phoQ knockout strain as reflected by enhanced growth of this strain in rice lines carrying XA21. These results suggest that the X. oryzae pv. oryzae PhoPQ TCS functions in virulence and in the production of AvrXA21 in partnership with RaxRH. PMID:18203830

Gene silencing using the recessive rice bacterial blight resistance gene xa13 as a new paradigm in plant breeding.

PubMed

Li, Changyan; Wei, Jing; Lin, Yongjun; Chen, Hao

2012-05-01

Resistant germplasm resources are valuable for developing resistant varieties in agricultural production. However, recessive resistance genes are usually overlooked in hybrid breeding. Compared with dominant traits, however, they may confer resistance to different pathogenic races or pest biotypes with different mechanisms of action. The recessive rice bacterial blight resistance gene xa13, also involved in pollen development, has been cloned and its resistance mechanism has been recently characterized. This report describes the conversion of bacterial blight resistance mediated by the recessive xa13 gene into a dominant trait to facilitate its use in a breeding program. This was achieved by knockdown of the corresponding dominant allele Xa13 in transgenic rice using recently developed artificial microRNA technology. Tissue-specific promoters were used to exclude most of the expression of artificial microRNA in the anther to ensure that Xa13 functioned normally during pollen development. A battery of highly bacterial blight resistant transgenic plants with normal seed setting rates were acquired, indicating that highly specific gene silencing had been achieved. Our success with xa13 provides a paradigm that can be adapted to other recessive resistance genes.

A comparative approach expands the protein-protein interaction node of the immune receptor XA21 in wheat and rice

PubMed Central

Yang, Baoju; Ruan, Randy; Cantu, Dario; Wang, Xiaodong; Ji, Wanquan; Ronald, Pamela C; Dubcovsky, Jorge

2016-01-01

The rice (Oryza sativa) OsXA21 receptor kinase is a well-studied immune receptor that initiates a signal transduction pathway leading to resistance to Xanthomonas oryzae pv. oryzae. Two homologs of OsXA21 were identified in wheat (Triticum aestivum): TaXA21-like1 located in a syntenic region with OsXA21, and TaXA21-like2 located in a non-syntenic region. Proteins encoded by these two wheat genes interact with four wheat orthologs of known OsXA21 interactors. In this study, we screened a wheat yeast-two-hybrid (Y2H) library using the cytosolic portion of TaXA21-like1 as bait to identify additional interactors. Using full-length T. aestivum and T. monococcum proteins and Y2H assays we identified three novel TaXA21-like1 interactors (TaARG, TaPR2, TmSKL1) plus one previously known in rice (TaSGT1). An additional full-length wheat protein (TaCIPK14) interacted with TaXA21-like2 and OsXA21 but not with TaXA21-like1. The interactions of TaXA21-like1 with TmSKL1 and TaSGT1 were also observed in rice protoplasts using bimolecular fluorescence complementation (BiFC) assays. We then cloned the rice homologs of the novel wheat interactors and confirmed that they all interact with OsXA21. This last result suggests that inter-specific comparative interactome analyses can be used not only to transfer known interactions from rice to wheat, but also to identify novel interactions in rice. PMID:23957671

Development of breeding lines with three pyramided resistance genes that confer broad-spectrum bacterial blight resistance and their molecular analysis in rice.

PubMed

Suh, Jung-Pil; Jeung, Ji-Ung; Noh, Tae-Hwan; Cho, Young-Chan; Park, So-Hyun; Park, Hyun-Su; Shin, Mun-Sik; Kim, Chung-Kon; Jena, Kshirod K

2013-02-08

The development of resistant cultivars has been the most effective and economical strategy to control bacterial leaf blight (BB) disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo). Molecular markers have made it possible to identify and pyramid valuable genes of agronomic importance in resistance rice breeding. In this study, three resistance genes (Xa4 + xa5 + Xa21) were transferred from an indica donor (IRBB57), using a marker-assisted backcrossing (MAB) breeding strategy, into a BB-susceptible elite japonica rice cultivar, Mangeumbyeo, which is high yielding with good grain quality. Our analysis led to the development of three elite advanced backcross breeding lines (ABL) with three resistance genes by foreground and phenotypic selection in a japonica genetic background without linkage drag. The background genome recovery of the ABL expressed more than 92.1% using genome-wide SSR marker analysis. The pathogenicity assays of three resistance-gene-derived ABL were conducted under glasshouse conditions with the 18 isolates of Xoo prevalent in Korea. The ABL exhibited very small lesion lengths, indicating a hypersensitive reaction to all 18 isolates of Xoo, with agronomic and grain quality traits similar to those of the recurrent parent. Pyramiding the resistance genes Xa4, xa5 and Xa21 provided a higher resistance to Xoo than the introduction of the individual resistance genes. Additionally, the combination of two dominant and one recessive BB resistance gene did not express any negative effect on agronomic traits in the ABL. The strategy of simultaneous foreground and phenotypic selection to introduce multiple R genes is very useful to reduce the cost and the time required for the isolation of desirable recombinants with target resistance genes in rice. The resistance-gene-derived ABL have practical breeding value without a yield penalty by providing broad-spectrum resistance against most of the existing isolates of BB in South Korea and will

Molecular breeding for the development of multiple disease resistance in Basmati rice.

PubMed

Singh, Atul; Singh, Vikas K; Singh, S P; Pandian, R T P; Ellur, Ranjith K; Singh, Devinder; Bhowmick, Prolay K; Gopala Krishnan, S; Nagarajan, M; Vinod, K K; Singh, U D; Prabhu, K V; Sharma, T R; Mohapatra, T; Singh, A K

2012-01-01

Basmati rice grown in the Indian subcontinent is highly valued for its unique culinary qualities. Production is, however, often constrained by diseases such as bacterial blight (BB), blast and sheath blight (ShB). The present study developed Basmati rice with inbuilt resistance to BB, blast and ShB using molecular marker-assisted selection. The rice cultivar 'Improved Pusa Basmati 1' (carrying the BB resistance genes xa13 and Xa21) was used as the recurrent parent and cultivar 'Tetep' (carrying the blast resistance gene Pi54 and ShB resistance quality trait loci (QTL), qSBR11-1) was the donor. Marker-assisted foreground selection was employed to identify plants possessing resistance alleles in the segregating generations along with stringent phenotypic selection for faster recovery of the recurrent parent genome (RPG) and phenome (RPP). Background analysis with molecular markers was used to estimate the recovery of RPG in improved lines. Foreground selection coupled with stringent phenotypic selection identified plants homozygous for xa13, Xa21 and Pi54, which were advanced to BC(2)F(5) through pedigree selection. Marker-assisted selection for qSBR11-1 in BC(2)F(5) using flanking markers identified seven homozygous families. Background analysis revealed that RPG recovery was up to 89.5%. Screening with highly virulent isolates of BB, blast and ShB showed that the improved lines were resistant to all three diseases and were on a par with 'Improved Pusa Basmati 1' for yield, duration and Basmati grain quality. This is the first report of marker-assisted transfer of genes conferring resistance to three different diseases in rice wherein genes xa13 and Xa21 for BB resistance, Pi54 for blast resistance, and a major QTL qSBR11-1 have been combined through marker-assisted backcross breeding. In addition to offering the potential for release as cultivars, the pyramided lines will serve as useful donors of gene(s) for BB, blast and ShB in future Basmati rice breeding

Incorporation of Bacterial Blight Resistance Genes Into Lowland Rice Cultivar Through Marker-Assisted Backcross Breeding.

PubMed

Pradhan, Sharat Kumar; Nayak, Deepak Kumar; Pandit, Elssa; Behera, Lambodar; Anandan, Annamalai; Mukherjee, Arup Kumar; Lenka, Srikanta; Barik, Durga Prasad

2016-07-01

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae is a major disease of rice in many rice growing countries. Pyramided lines carrying two BB resistance gene combinations (Xa21+xa13 and Xa21+xa5) were developed in a lowland cultivar Jalmagna background through backcross breeding by integrating molecular markers. In each backcross generation, markers closely linked to the disease resistance genes were used to select plants possessing the target genes. Background selection was continued in those plants carrying resistant genes until BC(3) generation. Plants having the maximum contribution from the recurrent parent genome were selected in each generation and hybridized with the recipient parent. The BB-pyramided line having the maximum recipient parent genome recovery of 95% was selected among BC3F1 plants and selfed to isolate homozygous BC(3)F(2) plants with different combinations of BB resistance genes. Twenty pyramided lines with two resistance gene combinations exhibited high levels of tolerance against the BB pathogen. In order to confirm the resistance, the pyramided lines were inoculated with different X. oryzae pv. oryzae strains of Odisha for bioassay. The genotypes with combination of two BB resistance genes conferred high levels of resistance to the predominant X. oryzae pv. oryzae isolates prevalent in the region. The pyramided lines showed similarity with the recipient parent with respect to major agro-morphologic traits.

RNA-Seq analysis reveals insight into enhanced rice Xa7-mediated bacterial blight resistance at high temperature.

PubMed

Cohen, Stephen P; Liu, Hongxia; Argueso, Cristiana T; Pereira, Andy; Vera Cruz, Casiana; Verdier, Valerie; Leach, Jan E

2017-01-01

Plant disease is a major challenge to agriculture worldwide, and it is exacerbated by abiotic environmental factors. During some plant-pathogen interactions, heat stress allows pathogens to overcome host resistance, a phenomenon which could severely impact crop productivity considering the global warming trends associated with climate change. Despite the importance of this phenomenon, little is known about the underlying molecular mechanisms. To better understand host plant responses during simultaneous heat and pathogen stress, we conducted a transcriptomics experiment for rice plants (cultivar IRBB61) containing Xa7, a bacterial blight disease resistance (R) gene, that were infected with Xanthomonas oryzae, the bacterial blight pathogen of rice, during high temperature stress. Xa7-mediated resistance is unusual relative to resistance mediated by other R genes in that it functions better at high temperatures. Using RNA-Seq technology, we identified 8,499 differentially expressed genes as temperature responsive in rice cultivar IRBB61 experiencing susceptible and resistant interactions across three time points. Notably, genes in the plant hormone abscisic acid biosynthesis and response pathways were up-regulated by high temperature in both mock-treated plants and plants experiencing a susceptible interaction and were suppressed by high temperature in plants exhibiting Xa7-mediated resistance. Genes responsive to salicylic acid, an important plant hormone for disease resistance, were down-regulated by high temperature during both the susceptible and resistant interactions, suggesting that enhanced Xa7-mediated resistance at high temperature is not dependent on salicylic acid signaling. A DNA sequence motif similar to known abscisic acid-responsive cis-regulatory elements was identified in the promoter region upstream of genes up-regulated in susceptible but down-regulated in resistant interactions. The results of our study suggest that the plant hormone abscisic

RNA-Seq analysis reveals insight into enhanced rice Xa7-mediated bacterial blight resistance at high temperature

PubMed Central

Argueso, Cristiana T.; Pereira, Andy; Vera Cruz, Casiana; Verdier, Valerie

2017-01-01

Plant disease is a major challenge to agriculture worldwide, and it is exacerbated by abiotic environmental factors. During some plant-pathogen interactions, heat stress allows pathogens to overcome host resistance, a phenomenon which could severely impact crop productivity considering the global warming trends associated with climate change. Despite the importance of this phenomenon, little is known about the underlying molecular mechanisms. To better understand host plant responses during simultaneous heat and pathogen stress, we conducted a transcriptomics experiment for rice plants (cultivar IRBB61) containing Xa7, a bacterial blight disease resistance (R) gene, that were infected with Xanthomonas oryzae, the bacterial blight pathogen of rice, during high temperature stress. Xa7-mediated resistance is unusual relative to resistance mediated by other R genes in that it functions better at high temperatures. Using RNA-Seq technology, we identified 8,499 differentially expressed genes as temperature responsive in rice cultivar IRBB61 experiencing susceptible and resistant interactions across three time points. Notably, genes in the plant hormone abscisic acid biosynthesis and response pathways were up-regulated by high temperature in both mock-treated plants and plants experiencing a susceptible interaction and were suppressed by high temperature in plants exhibiting Xa7-mediated resistance. Genes responsive to salicylic acid, an important plant hormone for disease resistance, were down-regulated by high temperature during both the susceptible and resistant interactions, suggesting that enhanced Xa7-mediated resistance at high temperature is not dependent on salicylic acid signaling. A DNA sequence motif similar to known abscisic acid-responsive cis-regulatory elements was identified in the promoter region upstream of genes up-regulated in susceptible but down-regulated in resistant interactions. The results of our study suggest that the plant hormone abscisic

Comparative Transcriptome Profiling of Rice Near-Isogenic Line Carrying Xa23 under Infection of Xanthomonas oryzae pv. oryzae.

PubMed

Tariq, Rezwan; Wang, Chunlian; Qin, Tengfei; Xu, Feifei; Tang, Yongchao; Gao, Ying; Ji, Zhiyuan; Zhao, Kaijun

2018-03-02

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae ( Xoo ), is an overwhelming disease in rice-growing regions worldwide. Our previous studies revealed that the executor R gene Xa23 confers broad-spectrum disease resistance to all naturally occurring biotypes of Xoo . In this study, comparative transcriptomic profiling of two near-isogenic lines (NILs), CBB23 (harboring Xa23 ) and JG30 (without Xa23 ), before and after infection of the Xoo strain, PXO99 A , was done by RNA sequencing, to identify genes associated with the resistance. After high throughput sequencing, 1645 differentially expressed genes (DEGs) were identified between CBB23 and JG30 at different time points. Gene Ontlogy (GO) analysis categorized the DEGs into biological process, molecular function, and cellular component. KEGG analysis categorized the DEGs into different pathways, and phenylpropanoid biosynthesis was the most prominent pathway, followed by biosynthesis of plant hormones, flavonoid biosynthesis, and glycolysis/gluconeogenesis. Further analysis led to the identification of differentially expressed transcription factors (TFs) and different kinase responsive genes in CBB23, than that in JG30. Besides TFs and kinase responsive genes, DEGs related to ethylene, jasmonic acid, and secondary metabolites were also identified in both genotypes after PXO99 A infection. The data of DEGs are a precious resource for further clarifying the network of Xa23 -mediated resistance.

Comparative Transcriptome Profiling of Rice Near-Isogenic Line Carrying Xa23 under Infection of Xanthomonas oryzae pv. oryzae

PubMed Central

Tariq, Rezwan; Wang, Chunlian; Qin, Tengfei; Xu, Feifei; Tang, Yongchao; Gao, Ying; Ji, Zhiyuan; Zhao, Kaijun

2018-01-01

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is an overwhelming disease in rice-growing regions worldwide. Our previous studies revealed that the executor R gene Xa23 confers broad-spectrum disease resistance to all naturally occurring biotypes of Xoo. In this study, comparative transcriptomic profiling of two near-isogenic lines (NILs), CBB23 (harboring Xa23) and JG30 (without Xa23), before and after infection of the Xoo strain, PXO99A, was done by RNA sequencing, to identify genes associated with the resistance. After high throughput sequencing, 1645 differentially expressed genes (DEGs) were identified between CBB23 and JG30 at different time points. Gene Ontlogy (GO) analysis categorized the DEGs into biological process, molecular function, and cellular component. KEGG analysis categorized the DEGs into different pathways, and phenylpropanoid biosynthesis was the most prominent pathway, followed by biosynthesis of plant hormones, flavonoid biosynthesis, and glycolysis/gluconeogenesis. Further analysis led to the identification of differentially expressed transcription factors (TFs) and different kinase responsive genes in CBB23, than that in JG30. Besides TFs and kinase responsive genes, DEGs related to ethylene, jasmonic acid, and secondary metabolites were also identified in both genotypes after PXO99A infection. The data of DEGs are a precious resource for further clarifying the network of Xa23-mediated resistance. PMID:29498672

Suppression of bacterial infection in rice by treatment with a sulfated peptide.

PubMed

Wei, Tong; Chern, Mawsheng; Liu, Furong; Ronald, Pamela C

2016-12-01

The rice XA21 receptor kinase confers robust resistance to bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo). A tyrosine-sulfated peptide from Xoo, called RaxX, triggers XA21-mediated immune responses, including the production of ethylene and reactive oxygen species and the induction of defence gene expression. It has not been tested previously whether these responses confer effective resistance to Xoo. Here, we describe a newly established post-inoculation treatment assay that facilitates investigations into the effect of the sulfated RaxX peptide in planta. In this assay, rice plants were inoculated with a virulent strain of Xoo and then treated with the RaxX peptide 2 days after inoculation. We found that post-inoculation treatment of XA21 plants with the sulfated RaxX peptide suppresses the development of Xoo infection in XA21 rice plants. The treated plants display restricted lesion development and reduced bacterial growth. Our findings demonstrate that exogenous application of sulfated RaxX activates XA21-mediated immunity in planta, and provides a potential strategy for the control of bacterial disease in the field. © 2016 BSPP and John Wiley & Sons Ltd.

Designer TAL effectors induce disease susceptibility and resistance to Xanthomonas oryzae pv. oryzae in rice.

PubMed

Li, Ting; Huang, Sheng; Zhou, Junhui; Yang, Bing

2013-05-01

TAL (transcription activator-like) effectors from Xanthomonas bacteria activate the cognate host genes, leading to disease susceptibility or resistance dependent on the genetic context of host target genes. The modular nature and DNA recognition code of TAL effectors enable custom-engineering of designer TAL effectors (dTALE) for gene activation. However, the feasibility of dTALEs as transcription activators for gene functional analysis has not been demonstrated. Here, we report the use of dTALEs, as expressed and delivered by the pathogenic Xanthomonas oryzae pv. oryzae (Xoo), in revealing the new function of two previously identified disease-related genes and the potential of one developmental gene for disease susceptibility in rice/Xoo interactions. The dTALE gene dTALE-xa27, designed to target the susceptible allele of the resistance gene Xa27, elicited a resistant reaction in the otherwise susceptible rice cultivar IR24. Four dTALE genes were made to induce the four annotated Xa27 homologous genes in rice cultivar Nipponbare, but none of the four induced Xa27-like genes conferred resistance to the dTALE-containing Xoo strains. A dTALE gene was also generated to activate the recessive resistance gene xa13, an allele of the disease-susceptibility gene Os8N3 (also named Xa13 or OsSWEET11, a member of sucrose efflux transporter SWEET gene family). The induction of xa13 by the dTALE rendered the resistant rice IRBB13 (xa13/xa13) susceptible to Xoo. Finally, OsSWEET12, an as-yet uncharacterized SWEET gene with no corresponding naturally occurring TAL effector identified, conferred susceptibility to the Xoo strains expressing the corresponding dTALE genes. Our results demonstrate that dTALEs can be delivered through the bacterial secretion system to activate genes of interest for functional analysis in plants.

Population structure and its effect on haplotype diversity and linkage disequilibrium surrounding the xa5 locus of rice (Oryza sativa L.).

PubMed Central

Garris, Amanda J; McCouch, Susan R; Kresovich, Stephen

2003-01-01

To assess the usefulness of linkage disequilibrium mapping in an autogamous, domesticated species, we have characterized linkage disequilibrium in the candidate region for xa5, a recessive gene conferring race-specific resistance to bacterial blight in rice. This trait and locus have good mapping information, a tractable phenotype, and available sequence data, but no cloned gene. We sampled 13 short segments from the 70-kb candidate region in 114 accessions of Oryza sativa. Five additional segments were sequenced from the adjacent 45-kb region in resistant accessions to estimate the distance at which linkage disequilibrium decays. The data show significant linkage disequilibrium between sites 100 kb apart. The presence of the xa5 resistant reaction in two ecotypes and in accessions with different haplotypes in the candidate region may indicate multiple origins or genetic heterogeneity for resistance. In addition, genetic differentiation between ecotypes emphasizes the need for controlling for population structure in the design of linkage disequilibrium studies in rice. PMID:14573486

The overexpression of RXam1, a cassava gene coding for an RLK, confers disease resistance to Xanthomonas axonopodis pv. manihotis.

PubMed

Díaz Tatis, Paula A; Herrera Corzo, Mariana; Ochoa Cabezas, Juan C; Medina Cipagauta, Adriana; Prías, Mónica A; Verdier, Valerie; Chavarriaga Aguirre, Paul; López Carrascal, Camilo E

2018-04-01

The overexpression of RXam1 leads to a reduction in bacterial growth of XamCIO136, suggesting that RXam1 might be implicated in strain-specific resistance. Cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis (Xam) is a prevalent disease in all regions, where cassava is cultivated. CBB is a foliar and vascular disease usually controlled through host resistance. Previous studies have found QTLs explaining resistance to several Xam strains. Interestingly, one QTL called XM5 that explained 13% of resistance to XamCIO136 was associated with a similar fragment of the rice Xa21-resistance gene called PCR250. In this study, we aimed to further identify and characterize this fragment and its role in resistance to CBB. Screening and hybridization of a BAC library using the molecular marker PCR250 as a probe led to the identification of a receptor-like kinase similar to Xa21 and were called RXam1 (Resistance to Xam 1). Here, we report the functional characterization of susceptible cassava plants overexpressing RXam1. Our results indicated that the overexpression of RXam1 leads to a reduction in bacterial growth of XamCIO136. This suggests that RXAM1 might be implicated in strain-specific resistance to XamCIO136.

The pepper Bs4C proteins are localized to the endoplasmic reticulum (ER) membrane and confer disease resistance to bacterial blight in transgenic rice.

PubMed

Wang, Jun; Zeng, Xuan; Tian, Dongsheng; Yang, Xiaobei; Wang, Lanlan; Yin, Zhongchao

2018-03-30

Transcription activator-like effector (TALE)-dependent dominant disease resistance (R) genes in plants, also referred to as executor R genes, are induced on infection by phytopathogenic bacteria of the genus Xanthomonas harbouring the corresponding TALE genes. Unlike the traditional R proteins, the executor R proteins do not determine the resistance specificity and may function broadly in different plant species. The executor R gene Bs4C-R in the resistant genotype PI 235047 of the pepper species Capsicum pubescens (CpBs4C-R) confers disease resistance to Xanthomonas campestris pv. vesicatoria (Xcv) harbouring the TALE genes avrBsP/avrBs4. In this study, the synthetic genes of CpBs4C-R and two other Bs4C-like genes, the susceptible allele in the genotype PI585270 of C. pubescens (CpBs4C-S) and the CaBs4C-R homologue gene in the cultivar 'CM334' of Capsicum annum (CaBs4C), were characterized in tobacco (Nicotiana benthamiana) and rice (Oryza sativa). The Bs4C genes induced cell death in N. benthamiana. The functional Bs4C-eCFP fusion proteins were localized to the endoplasmic reticulum (ER) membrane in the leaf epidermal cells of N. benthamiana. The Xa10 promoter-Bs4C fusion genes in transgenic rice conferred strain-specific disease resistance to Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight in rice, and were specifically induced by the Xa10-incompatible Xoo strain PXO99 A (pHM1avrXa10). The results indicate that the Bs4C proteins from pepper species function broadly in rice and the Bs4C protein-mediated cell death from the ER is conserved between dicotyledonous and monocotyledonous plants, which can be utilized to engineer novel and enhanced disease resistance in heterologous plants. © 2018 TEMASEK LIFE SCIENCES LABORATORY. MOLECULAR PLANT PATHOLOGY © 2018 JOHN WILEY & SONS LTD.

MicroRNA-520g Confers Drug Resistance by Regulating p21 Expression in Colorectal Cancer*

PubMed Central

Zhang, Yang; Geng, Liying; Talmon, Geoffrey; Wang, Jing

2015-01-01

Development of drug resistance is one of the major causes of colorectal cancer recurrence, yet mechanistic understanding and therapeutic options remain limited. Here, we show that expression of microRNA (miR)-520g is correlated with drug resistance of colon cancer cells. Ectopic expression of miR-520g conferred resistance to 5-fluorouracil (5-FU)- or oxaliplatin-induced apoptosis in vitro and reduced the effectiveness of 5-FU in the inhibition of tumor growth in a mouse xenograft model in vivo. Further studies indicated that miR-520g mediated drug resistance through down-regulation of p21 expression. Moreover, p53 suppressed miR-520g expression, and deletion of p53 up-regulated miR-520g expression. Inhibition of miR-520g in p53−/− cells increased their sensitivity to 5-FU treatment. Importantly, studies of patient samples indicated that expression of miR-520g correlated with chemoresistance in colorectal cancer. These findings indicate that the p53/miR-520g/p21 signaling axis plays an important role in the response of colorectal cancer to chemotherapy. A major implication of our studies is that inhibition of miR-520g or restoration of p21 expression may have considerable therapeutic potential to overcome drug resistance in colorectal cancer patients, especially in those with mutant p53. PMID:25616665

Identification and fine-mapping of Xa33, a novel gene for resistance to Xanthomonas oryzae pv. oryzae.

PubMed

Kumar, P Natraj; Sujatha, K; Laha, G S; Rao, K Srinivasa; Mishra, B; Viraktamath, B C; Hari, Y; Reddy, C S; Balachandran, S M; Ram, T; Madhav, M Sheshu; Rani, N Shobha; Neeraja, C N; Reddy, G Ashok; Shaik, H; Sundaram, R M

2012-02-01

Broadening of the genetic base for identification and transfer of genes for resistance to insect pests and diseases from wild relatives of rice is an important strategy in resistance breeding programs across the world. An accession of Oryza nivara, International Rice Germplasm Collection (IRGC) accession number 105710, was identified to exhibit high level and broad-spectrum resistance to Xanthomonas oryzae pv. oryzae. In order to study the genetics of resistance and to tag and map the resistance gene or genes present in IRGC 105710, it was crossed with the bacterial blight (BB)-susceptible varieties 'TN1' and 'Samba Mahsuri' (SM) and then backcrossed to generate backcross mapping populations. Analysis of these populations and their progeny testing revealed that a single dominant gene controls resistance in IRGC 105710. The BC(1)F(2) population derived from the cross IRGC 105710/TN1//TN1 was screened with a set of 72 polymorphic simple-sequence repeat (SSR) markers distributed across the rice genome and the resistance gene was coarse mapped on chromosome 7 between the SSR markers RM5711 and RM6728 at a genetic distance of 17.0 and 19.3 centimorgans (cM), respectively. After analysis involving 49 SSR markers located between the genomic interval spanned by RM5711 and RM6728, and BC(2)F(2) population consisting of 2,011 individuals derived from the cross IRGC 105710/TN1//TN1, the gene was fine mapped between two SSR markers (RMWR7.1 and RMWR7.6) located at a genetic distance of 0.9 and 1.2 cM, respectively, from the gene and flanking it. The linkage distances were validated in a BC(1)F(2) mapping population derived from the cross IRGC 105710/SM//2 × SM. The BB resistance gene present in the O. nivara accession was identified to be novel based on its unique map location on chromosome 7 and wider spectrum of BB resistance; this gene has been named Xa33. The genomic region between the two closely flanking SSR markers was in silico analyzed for putatively expressed

Antithrombotic effects of factor Xa inhibition with DU-176b: Phase-I study of an oral, direct factor Xa inhibitor using an ex-vivo flow chamber.

PubMed

Zafar, Mohammad Urooj; Vorchheimer, David A; Gaztanaga, Juan; Velez, Mauricio; Yadegar, Daniel; Moreno, Pedro R; Kunitada, Satoshi; Pagan, Juan; Fuster, Valentin; Badimon, Juan J

2007-10-01

Direct and specific inhibition of factor Xa is an emerging therapeutic strategy for atherothrombotic disease. Parenteral factor Xa inhibitors promise efficacy comparable to standard therapies, which could be extended to ambulatory patients with oral agents. We evaluated the antithrombotic effect of the oral, direct factor Xa inhibitor DU-176b in a phase-I study. Healthy subjects (n = 12) received a single, 60 mg dose of DU-176b. Antithrombotic effects were assessed by comparing ex-vivo thrombus formation at 1.5, 5, and 12 hours post-dose versus baseline, along with factor Xa activity, thrombin generation and clotting parameters. Under venous flow after 1.5 and 5 hours, the thrombus was 28% and 21% smaller versus baseline, respectively (p < 0.05). Under arterial condition, the reduction was 26% and 17% (p < 0.05). Thrombin generation decreased by 28% at 1.5 hours and 10% at 5 hours. Changes in PT and INR correlated well with plasma drug concentrations (R2 = 0.79 and 0.78). Direct and specific inhibition of factor Xa by DU-176b significantly reduced ex-vivo thrombus formation at both venous and arterial rheologies, up to 5 hours post-dose. The effects mirrored changes in clotting parameters, suggesting their potential usefulness for monitoring in a clinical setting.

HIV Conference to Be Held on October 21 at NCI at Frederick | Poster

Cancer.gov

By Anne Arthur, Guest Writer The HIV Drug Resistance Program Conference on “Virus Structure: Putting the Pieces Together” will be held at NCI at Frederick on October 21, 2014, from 1:00 to 5:45 p.m. in the Conference Center auditorium, Building 549.

Clinical Scenarios for Discordant Anti-Xa

PubMed Central

Vera-Aguilera, Jesus; Yousef, Hindi; Beltran-Melgarejo, Diego; Teng, Teng Hugh; Jan, Ramos; Mok, Mary; Vera-Aguilera, Carlos; Moreno-Aguilera, Eduardo

2016-01-01

Anti-Xa test measures the activity of heparin against the activity of activated coagulation factor X; significant variability of anti-Xa levels in common clinical scenarios has been observed. Objective. To review the most common clinical settings in which anti-Xa results can be bias. Evidence Review. Guidelines and current literature search: we used PubMed, Medline, Embase, and MEDION, from 2000 to October 2013. Results. Anti-Xa test is widely used; however the assay underestimates heparin concentration in the presence of significant AT deficiency, pregnancy, end stage renal disease, and postthrombolysis and in patients with hyperbilirubinemia; limited published data evaluating the safety and effectiveness of anti-Xa assays for managing UH therapy is available. Conclusions and Relevance. To our knowledge this is the first paper that summarizes the most common causes in which this assay can be affected, several “day to day” clinical scenarios can modify the outcomes, and we concur that these rarely recognized scenarios can be affected by negative outcomes in the daily practice. PMID:27293440

Do transgenesis and marker-assisted backcross breeding produce substantially equivalent plants? A comparative study of transgenic and backcross rice carrying bacterial blight resistant gene Xa21.

PubMed

Gao, Lifen; Cao, Yinghao; Xia, Zhihui; Jiang, Guanghuai; Liu, Guozhen; Zhang, Weixiong; Zhai, Wenxue

2013-10-29

The potential impact of genetically modified (GM) plants on human health has attracted much attention worldwide, and the issue remains controversial. This is in sharp contrast to the broad acceptance of plants produced by breeding through Marker Assisted Backcrossing (MAB). Focusing on transcriptome variation and perturbation to signaling pathways, we assessed the molecular and biological aspects of substantial equivalence, a general principle for food safety endorsed by the Food and Agricultural Organization and the World Health Organization, between a transgenic crop and a plant from MAB breeding. We compared a transgenic rice line (DXT) and a MAB rice line (DXB), both of which contain the gene Xa21 providing resistance to bacterial leaf blight. By using Next-Generation sequencing data of DXT, DXB and their parental line (D62B), we compared the transcriptome variation of DXT and DXB. Remarkably, DXT had 43% fewer differentially expressed genes (DEGs) than DXB. The genes exclusively expressed in DXT and in DXB have pathogen and stress defense functions. Functional categories of DEGs in DXT were comparable to that in DXB, and seven of the eleven pathways significantly affected by transgenesis were also perturbed by MAB breeding. These results indicated that the transgenic rice and rice from MAB breeding are substantial equivalent at the transcriptome level, and paved a way for further study of transgenic rice, e.g., understanding the chemical and nutritional properties of the DEGs identified in the current study.

Do transgenesis and marker-assisted backcross breeding produce substantially equivalent plants? - A comparative study of transgenic and backcross rice carrying bacterial blight resistant gene Xa21

PubMed Central

2013-01-01

Background The potential impact of genetically modified (GM) plants on human health has attracted much attention worldwide, and the issue remains controversial. This is in sharp contrast to the broad acceptance of plants produced by breeding through Marker Assisted Backcrossing (MAB). Results Focusing on transcriptome variation and perturbation to signaling pathways, we assessed the molecular and biological aspects of substantial equivalence, a general principle for food safety endorsed by the Food and Agricultural Organization and the World Health Organization, between a transgenic crop and a plant from MAB breeding. We compared a transgenic rice line (DXT) and a MAB rice line (DXB), both of which contain the gene Xa21 providing resistance to bacterial leaf blight. By using Next-Generation sequencing data of DXT, DXB and their parental line (D62B), we compared the transcriptome variation of DXT and DXB. Remarkably, DXT had 43% fewer differentially expressed genes (DEGs) than DXB. The genes exclusively expressed in DXT and in DXB have pathogen and stress defense functions. Functional categories of DEGs in DXT were comparable to that in DXB, and seven of the eleven pathways significantly affected by transgenesis were also perturbed by MAB breeding. Conclusions These results indicated that the transgenic rice and rice from MAB breeding are substantial equivalent at the transcriptome level, and paved a way for further study of transgenic rice, e.g., understanding the chemical and nutritional properties of the DEGs identified in the current study. PMID:24165682

How useful is determination of anti-factor Xa activity to guide bridging therapy with enoxaparin? A pilot study.

PubMed

Hammerstingl, Christoph; Omran, Heyder; Tripp, Christian; Poetzsch, Bernd

2009-02-01

Low-molecular-weight heparins (LMWH) are commonly used as peri-procedural bridging anticoagulants. The usefulness of measurement of anti-factor Xa activity (anti-Xa) to guide bridging therapy with LMWH is unknown. It was the objective of this study to determine levels of anti-Xa during standard bridging therapy with enoxaparin, and to examine predictors for residual anti-Xa. Consecutive patients receiving enoxaparin at a dosage of 1 mg/kg body weight/12 hours for temporary interruption of phenprocoumon were prospectively enrolled to the study. Blood-samples were obtained 14 hours after LMWH-application immediately pre- procedurally. Procedural details, clinical and demographic data were collected and subsequently analyzed. Seventy patients were included (age 75.2 +/- 10.8 years, Cr Cl 55.7 +/- 21.7ml/min, body mass index [BMI] 27.1 +/- 4.9). LMWH- therapy was for a mean of 4.2 +/- 1.6 days; overall anti-Xa was 0.58 +/- 0.32 U/ml. In 37 (52.8%) of patients anti-Xa was > or U/ml, including 10 (14.3%) patients with anti-Xa > 1U/ml. Linear regression analysis of single variables and logistic multivariable regression analysis failed to prove a correlation between anti-Xa and single or combined factors. No major bleeding, no thromboembolism and four (5.7%) minor haemorrhages were observed. When bridging OAC with therapeutic doses of enoxaparin a high percentage of patients undergo interventions with high residual anti-Xa. The levels of anti-Xa vary largely and are independent of single or combined clinical variables. Since the anti-Xa-related outcome of patients receiving bridging therapy with LMWH is not investigated, no firm recommendation on the usefulness of monitoring of anti-Xa can be given at this stage.

Analysis of nucleotide diversity among alleles of the major bacterial blight resistance gene Xa27 in cultivars of rice (Oryza sativa) and its wild relatives.

PubMed

Bimolata, Waikhom; Kumar, Anirudh; Sundaram, Raman Meenakshi; Laha, Gouri Shankar; Qureshi, Insaf Ahmed; Reddy, Gajjala Ashok; Ghazi, Irfan Ahmad

2013-08-01

Xa27 is one of the important R-genes, effective against bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo). Using natural population of Oryza, we analyzed the sequence variation in the functionally important domains of Xa27 across the Oryza species. DNA sequences of Xa27 alleles from 27 rice accessions revealed higher nucleotide diversity among the reported R-genes of rice. Sequence polymorphism analysis revealed synonymous and non-synonymous mutations in addition to a number of InDels in non-coding regions of the gene. High sequence variation was observed in the promoter region including the 5'UTR with 'π' value 0.00916 and 'θ w ' = 0.01785. Comparative analysis of the identified Xa27 alleles with that of IRBB27 and IR24 indicated the operation of both positive selection (Ka/Ks > 1) and neutral selection (Ka/Ks ≈ 0). The genetic distances of alleles of the gene from Oryza nivara were nearer to IRBB27 as compared to IR24. We also found the presence of conserved and null UPT (upregulated by transcriptional activator) box in the isolated alleles. Considerable amino acid polymorphism was localized in the trans-membrane domain for which the functional significance is yet to be elucidated. However, the absence of functional UPT box in all the alleles except IRBB27 suggests the maintenance of single resistant allele throughout the natural population.

Kinetic characterization of factor Xa binding using a quenched fluorescent substrate based on the reactive site of factor Xa inhibitor from Bauhinia ungulata seeds.

PubMed

Oliva, M L V; Andrade, S A; Juliano, M A; Sallai, R C; Torquato, R J; Sampaio, M U; Pott, V J; Sampaio, C A M

2003-07-01

The specific Kunitz Bauhinia ungulata factor Xa inhibitor (BuXI) and the Bauhinia variegata trypsin inhibitor (BvTI) blocked the activity of trypsin, chymotrypsin, plasmin, plasma kallikrein and factor XIIa, and factor Xa inhibition was achieved only by BuXI (K(i) 14 nM). BuXI and BvTI are highly homologous (70%). The major differences are the methionine residues at BuXI reactive site, which are involved in the inhibition, since the oxidized protein no longer inhibits factor Xa but maintains the trypsin inhibition. Quenched fluorescent substrates based on the reactive site sequence of the inhibitors were synthesized and the kinetic parameters of the hydrolysis were determined using factor Xa and trypsin. The catalytic efficiency k(cat)/K(m) 4.3 x 10(7) M(-1)sec(>-1) for Abz-VMIAALPRTMFIQ-EDDnp (lead peptide) hydrolysis by factor Xa was 10(4)-fold higher than that of Boc-Ile-Glu-Gly-Arg-AMC, widely used as factor Xa substrate. Lengthening of the substrate changed its susceptibility to factor Xa hydrolysis. Both methionine residues in the substrate influence the binding to factor Xa. Serine replacement of threonine (P(1)') decreases the catalytic efficiency by four orders of magnitude. Factor Xa did not hydrolyze the substrate containing the reactive site sequence of BvTI, that inhibits trypsin inhibitor but not factor Xa. Abz-VMIAALPRTMFIQ-EDDnp prolonged both the prothrombin time and the activated partial thromboplastin time, and the other modified substrates used in this experiment altered blood-clotting assays.

Expression of the Grape VqSTS21 Gene in Arabidopsis Confers Resistance to Osmotic Stress and Biotrophic Pathogens but Not Botrytis cinerea

PubMed Central

Huang, Li; Zhang, Songlin; Singer, Stacy D.; Yin, Xiangjing; Yang, Jinhua; Wang, Yuejin; Wang, Xiping

2016-01-01

Stilbene synthase (STS) is a key gene in the biosynthesis of various stilbenoids, including resveratrol and its derivative glucosides (such as piceid), that has been shown to contribute to disease resistance in plants. However, the mechanism behind such a role has yet to be elucidated. Furthermore, the function of STS genes in osmotic stress tolerance remains unclear. As such, we sought to elucidate the role of STS genes in the defense against biotic and abiotic stress in the model plant Arabidopsis thaliana. Expression profiling of 31 VqSTS genes from Vitis quinquangularis revealed that VqSTS21 was up-regulated in response to powdery mildew (PM) infection. To provide a deeper understanding of the function of this gene, we cloned the full-length coding sequence of VqSTS21 and overexpressed it in Arabidopsis thaliana via Agrobacterium-mediated transformation. The resulting VqSTS21 Arabidopsis lines produced trans-piceid rather than resveratrol as their main stilbenoid product and exhibited improved disease resistance to PM and Pseudomonas syringae pv. tomato DC3000, but displayed increased susceptibility to Botrytis cinerea. In addition, transgenic Arabidopsis lines were found to confer tolerance to salt and drought stress from seed germination through plant maturity. Intriguingly, qPCR assays of defense-related genes involved in salicylic acid, jasmonic acid, and abscisic acid-induced signaling pathways in these transgenic lines suggested that VqSTS21 plays a role in various phytohormone-related pathways, providing insight into the mechanism behind VqSTS21-mediated resistance to biotic and abiotic stress. PMID:27695466

21 CFR 1316.54 - Prehearing conference.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Prehearing conference. 1316.54 Section 1316.54 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE ADMINISTRATIVE FUNCTIONS... to be called. (e) The advance submission at the prehearing conference of all documentary evidence and...

Novel factor Xa inhibitors: a patent review.

PubMed

de Candia, Modesto; Lopopolo, Gianfranco; Altomare, Cosimo

2009-11-01

New oral anticoagulants with favorable safety profiles and fixed doses are required for the management of thromboembolism and stroke prevention in patients with atrial fibrillation. Among them, fXa inhibitors (the so-called xabans) are attractive options that can overcome limitations (e.g., bleeding) of the current oral antithrombotic therapy. The rational design of small-molecule direct fXa inhibitors, whose importance is testified by the growing number of publications and patents recently registered, has been fully supported by the X-ray crystallography of enzyme-ligand complexes. Pubmed, SciFinder Scholar, ISI web of knowledge(SM), http://ep.espacenet.com/ and Google websites were used as the main sources for literature retrieving, and > 100 patents filed between 2006 and April 2009, reviewed and discussed herein, highlight the variety among the P1 and P4 moieties on suitable scaffolds. The replacement of the benzamidine P1 moiety, which characterizes the first generation, with less basic bioisosteric or nonpolar neutral P1 groups led to the disclosure of numerous fXa inhibitors with high potency, selectivity and oral bioavailability. Novel selective fXa inhibitors with stable pharmacokinetics, better therapeutic windows and ease-of-use than the existing anticoagulants are currently under advanced stage clinical trials. Available data from Phase II and Phase III studies reflect the drive towards fXa inhibitors as potentially more effective and safer antithrombotic drugs. Their development is expected to address two major needs for anticoagulation, namely safety and ease-of-use, and to significantly affect the anticoagulant market.

Expedition 21 Prelaunch Press Conference

NASA Image and Video Library

2009-09-28

Spaceflight Participant Guy Laliberté, left, Expedition 21 Flight Engineer Maxim Suraev, center, and Expedition 21 Flight Engineer Jeffrey N. Williams wave hello and point to members of their families at the start of the press conference, Tuesday, Sept. 29, 2009 at the Cosmonaut Hotel in Baikonur, Kazakhstan. Photo Credit: (NASA/Bill Ingalls)

Improvement of Basmati rice varieties for resistance to blast and bacterial blight diseases using marker assisted backcross breeding.

PubMed

Ellur, Ranjith K; Khanna, Apurva; Yadav, Ashutosh; Pathania, Sandeep; Rajashekara, H; Singh, Vikas K; Gopala Krishnan, S; Bhowmick, Prolay K; Nagarajan, M; Vinod, K K; Prakash, G; Mondal, Kalyan K; Singh, Nagendra K; Vinod Prabhu, K; Singh, Ashok K

2016-01-01

Marker assisted backcross breeding was employed to incorporate the blast resistance genes, Pi2 and Pi54 and bacterial blight (BB) resistance genes xa13 and Xa21 into the genetic background of Pusa Basmati 1121 (PB1121) and Pusa Basmati 6. Foreground selection for target gene(s) was followed by arduous phenotypic and background selection which fast-tracked the recovery of recurrent parent genome (RPG) to an extent of 95.8% in one of the near-isogenic lines (NILs) namely, Pusa 1728-23-33-31-56, which also showed high degree of resemblance to recurrent parent, PB6 in phenotype. The phenotypic selection prior to background selection provided an additional opportunity for identifying the novel recombinants viz., Pusa 1884-9-12-14 and Pusa 1884-3-9-175, superior to parental lines in terms of early maturity, higher yield and improved quality parameters. There was no significant difference between the RPG recovery estimated based on SSR or SNP markers, however, the panel of SNPs markers was considered as the better choice for background selection as it provided better genome coverage and included SNPs in the genic regions. Multi-location evaluation of NILs depicted their stable and high mean performance in comparison to the respective recurrent parents. The Pi2+Pi54 carrying NILs were effective in combating a pan-India panel of Magnaporthe oryzae isolates with high level of field resistance in northern, eastern and southern parts of India. Alongside, the PB1121-NILs and PB6-NILs carrying BB resistance genes xa13+Xa21 were resistant against Xanthomonas oryzae pv. oryzae races of north-western, southern and eastern parts of the country. Three of NILs developed in this study, have been promoted to final stage of testing during the ​Kharif 2015 in the Indian National Basmati Trial. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A specific antidote for reversal of anticoagulation by direct and indirect inhibitors of coagulation factor Xa.

PubMed

Lu, Genmin; DeGuzman, Francis R; Hollenbach, Stanley J; Karbarz, Mark J; Abe, Keith; Lee, Gail; Luan, Peng; Hutchaleelaha, Athiwat; Inagaki, Mayuko; Conley, Pamela B; Phillips, David R; Sinha, Uma

2013-04-01

Inhibitors of coagulation factor Xa (fXa) have emerged as a new class of antithrombotics but lack effective antidotes for patients experiencing serious bleeding. We designed and expressed a modified form of fXa as an antidote for fXa inhibitors. This recombinant protein (r-Antidote, PRT064445) is catalytically inactive and lacks the membrane-binding γ-carboxyglutamic acid domain of native fXa but retains the ability of native fXa to bind direct fXa inhibitors as well as low molecular weight heparin-activated antithrombin III (ATIII). r-Antidote dose-dependently reversed the inhibition of fXa by direct fXa inhibitors and corrected the prolongation of ex vivo clotting times by such inhibitors. In rabbits treated with the direct fXa inhibitor rivaroxaban, r-Antidote restored hemostasis in a liver laceration model. The effect of r-Antidote was mediated by reducing plasma anti-fXa activity and the non-protein bound fraction of the fXa inhibitor in plasma. In rats, r-Antidote administration dose-dependently and completely corrected increases in blood loss resulting from ATIII-dependent anticoagulation by enoxaparin or fondaparinux. r-Antidote has the potential to be used as a universal antidote for a broad range of fXa inhibitors.

Addition of transcription activator-like effector binding sites to a pathogen strain-specific rice bacterial blight resistance gene makes it effective against additional strains and against bacterial leaf streak.

PubMed

Hummel, Aaron W; Doyle, Erin L; Bogdanove, Adam J

2012-09-01

Xanthomonas transcription activator-like (TAL) effectors promote disease in plants by binding to and activating host susceptibility genes. Plants counter with TAL effector-activated executor resistance genes, which cause host cell death and block disease progression. We asked whether the functional specificity of an executor gene could be broadened by adding different TAL effector binding elements (EBEs) to it. We added six EBEs to the rice Xa27 gene, which confers resistance to strains of the bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) that deliver the TAL effector AvrXa27. The EBEs correspond to three other effectors from Xoo strain PXO99(A) and three from strain BLS256 of the bacterial leaf streak pathogen Xanthomonas oryzae pv. oryzicola (Xoc). Stable integration into rice produced healthy lines exhibiting gene activation by each TAL effector, and resistance to PXO99(A) , a PXO99(A) derivative lacking AvrXa27, and BLS256, as well as two other Xoo and 10 Xoc strains virulent toward wildtype Xa27 plants. Transcripts initiated primarily at a common site. Sequences in the EBEs were found to occur nonrandomly in rice promoters, suggesting an overlap with endogenous regulatory sequences. Thus, executor gene specificity can be broadened by adding EBEs, but caution is warranted because of the possible coincident introduction of endogenous regulatory elements. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses.

PubMed

Schwessinger, Benjamin; Bahar, Ofir; Thomas, Nicholas; Thomas, Nicolas; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E; Daudi, Arsalan; Petzold, Christopher J; Singan, Vasanth R; Kuo, Rita; Chovatia, Mansi; Daum, Christopher; Heazlewood, Joshua L; Zipfel, Cyril; Ronald, Pamela C

2015-03-01

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.

Transgenic Expression of the Dicotyledonous Pattern Recognition Receptor EFR in Rice Leads to Ligand-Dependent Activation of Defense Responses

PubMed Central

Thomas, Nicolas; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E.; Daudi, Arsalan; Petzold, Christopher J.; Singan, Vasanth R.; Kuo, Rita; Chovatia, Mansi; Daum, Christopher; Heazlewood, Joshua L.; Zipfel, Cyril; Ronald, Pamela C.

2015-01-01

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components. PMID:25821973

Expedition 21 Prelaunch Press Conference

NASA Image and Video Library

2009-09-28

Spaceflight Participant Guy Laliberté, left, Expedition 21 Flight Engineer Maxim Suraev, center, and Expedition 21 Flight Engineer Jeffrey N. Williams reveal t-shirts showing their faces superimposed on characters from the Russian movie "White Sun of the Desert" at the end of the press conference, Tuesday, Sept. 29, 2009 at the Cosmonaut Hotel in Baikonur, Kazakhstan. It is tradition for all crews flying on the Soyuz to watch this movie several days before they launch. Photo Credit: (NASA/Bill Ingalls)

Fast rotation of a subkilometer-sized near-Earth object 2011 XA{sub 3}

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

Urakawa, Seitaro; Ohtsuka, Katsuhito; Abe, Shinsuke

2014-05-01

We present light curve observations and their multiband photometry for near-Earth object (NEO) 2011 XA{sub 3}. The light curve has shown a periodicity of 0.0304 ± 0.0003 days (= 43.8 ± 0.4 minutes). The fast rotation shows that 2011 XA{sub 3} is in a state of tension (i.e., a monolithic asteroid) and cannot be held together by self-gravitation. Moreover, the multiband photometric analysis indicates that the taxonomic class of 2011 XA{sub 3} is S-complex, or V-type. Its estimated effective diameter is 225 ± 97 m (S-complex) and 166 ± 63 m (V-type), respectively. Therefore, 2011 XA{sub 3} is a candidatemore » for the second-largest, fast-rotating, monolithic asteroid. Moreover, the orbital parameters of 2011 XA{sub 3} are apparently similar to those of NEO (3200) Phaethon, but F/B-type. We computed the orbital evolutions of 2011 XA{sub 3} and Phaethon. However, the results of the computation and distinct taxonomy indicate that neither of the asteroids is of common origin.« less

Recombinant Rp1 genes confer necrotic or nonspecific resistance phenotypes.

PubMed

Smith, Shavannor M; Steinau, Martin; Trick, Harold N; Hulbert, Scot H

2010-06-01

Genes at the Rp1 rust resistance locus of maize confer race-specific resistance to the common rust fungus Puccinia sorghi. Three variant genes with nonspecific effects (HRp1 -Kr1N, -D*21 and -MD*19) were found to be generated by intragenic crossing over within the LRR region. The LRR region of most NBS-LRR encoding genes is quite variable and codes for one of the regions in resistance gene proteins that controls specificity. Sequence comparisons demonstrated that the Rp1-Kr1N recombinant gene was identical to the N-terminus of the rp1-kp2 gene and C-terminus of another gene from its HRp1-K grandparent. The Rp1-D*21 recombinant gene consists of the N-terminus of the rp1-dp2 gene and C-terminus of the Rp1-D gene from the parental haplotype. Similarly, a recombinant gene from the Rp1-MD*19 haplotype has the N-terminus of an rp1 gene from the HRp1-M parent and C-terminus of the rp1-D19 gene from the HRp1-D parent. The recombinant Rp1 -Kr1N, -D*21 and -MD*19 genes activated defense responses in the absence of their AVR proteins triggering HR (hypersensitive response) in the absence of the pathogen. The results indicate that the frequent intragenic recombination events that occur in the Rp1 gene cluster not only recombine the genes into novel haplotypes, but also create genes with nonspecific effects. Some of these may contribute to nonspecific quantitative resistance but others have severe consequences for the fitness of the plant.

21st Space Simulation Conference: The Future of Space Simulation Testing in the 21st Century

NASA Technical Reports Server (NTRS)

Stecher, Joseph L., III (Compiler)

2000-01-01

The Institute of Environmental Sciences and Technology's Twenty-first Space Simulation Conference, "The Future of Space Testing in the 21st Century" provided participants with a forum to acquire and exchange information on the state-of-the-art in space simulation, test technology, atomic oxygen, programs/system testing, dynamics testing, contamination, and materials. The papers presented at this conference and the resulting discussions carried out the conference theme "The Future of Space Testing in the 21st Century."

Integrating marker-assisted background analysis with foreground selection for pyramiding bacterial blight resistance genes into Basmati rice.

PubMed

Baliyan, Nikita; Malik, Rekha; Rani, Reema; Mehta, Kirti; Vashisth, Urvashi; Dhillon, Santosh; Boora, Khazan Singh

2018-01-01

Bacterial leaf blight (BB), caused by the bacterium Xanthomonas oryzae pv. Oryzae (Xoo), is the major constraint amongst rice diseases in India. CSR-30 is a very popular high-yielding, salt-tolerant Basmati variety widely grown in Haryana, India, but highly susceptible to BB. In the present study, we have successfully introgressed three BB resistance genes (Xa21, xa13 and xa5) from BB-resistant donor variety IRBB-60 into the BB-susceptible Basmati variety CSR-30 through marker-assisted selection (MAS) exercised with stringent phenotypic selection without compromising the Basmati traits. Background analysis using 131 polymorphic SSR markers revealed that recurrent parent genome (RPG) recovery ranged up to 97.1% among 15 BC 3 F 1 three-gene-pyramided genotypes. Based on agronomic evaluation, BB reaction, aroma, percentage recovery of RPG, and grain quality evaluation, four genotypes, viz., IC-R28, IC-R68, IC-R32, and IC-R42, were found promising and advanced to BC 3 F 2 generation. Copyright © 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Measuring Anti–Factor Xa Activity to Monitor Low-Molecular-Weight Heparin in Obesity: A Critical Review

PubMed Central

Egan, Gregory; Ensom, Mary H H

2015-01-01

Background: The choice of whether to monitor anti–factor Xa (anti-Xa) activity in patients who are obese and who are receiving low-molecular-weight heparin (LMWH) therapy is controversial. To the authors’ knowledge, no systematic review of monitoring of anti-Xa activity in such patients has been published to date. Objective: To systematically ascertain the utility of monitoring anti-Xa concentrations for LMWH therapy in obese patients. Data Sources: MEDLINE (1946 to September 2014), the Cochrane Database of Systematic Reviews, Embase (1974 to September 2014), PubMed (1947 to September 2014), International Pharmaceutical Abstracts (1970 to September 2014), and Scopus were searched using the terms obesity, morbid obesity, thrombosis, venous thrombosis, embolism, venous thromboembolism, pulmonary embolism, low-molecular weight heparin, enoxaparin, dalteparin, tinzaparin, anti-factor Xa, anti-factor Xa monitoring, anti-factor Xa activity, and anti-factor Xa assay. The reference lists of retrieved articles were also reviewed. Study Selection and Data Extraction: English-language studies describing obese patients treated with LMWH or reporting anti-Xa activity were reviewed using a 9-step decision-making algorithm to determine whether monitoring of LMWH therapy by means of anti-Xa activity in obesity is warranted. Studies published in abstract form were excluded. Data Synthesis: The analysis showed that anti-Xa concentrations are not strongly associated with thrombosis or hemorrhage. In clinical studies of LMWH for thromboprophylaxis in bariatric surgery, orthopedic surgery, general surgery, and medical patients, and for treatment of venous thrombo embolism and acute coronary syndrome, anti-Xa activity can be predicted from dose of LMWH and total body weight; no difference in clinical outcome was found between obese and non-obese participants. Conclusions: Routinely determining anti-Xa concentrations in obese patients to monitor the clinical effectiveness of LMWH is

Error-prone PCR mutation of Ls-EPSPS gene from Liriope spicata conferring to its enhanced glyphosate-resistance.

PubMed

Mao, Chanjuan; Xie, Hongjie; Chen, Shiguo; Valverde, Bernal E; Qiang, Sheng

2017-09-01

Liriope spicata (Thunb.) Lour has a unique LsEPSPS structure contributing to the highest-ever-recognized natural glyphosate tolerance. The transformed LsEPSPS confers increased glyphosate resistance to E. coli and A. thaliana. However, the increased glyphosate-resistance level is not high enough to be of commercial value. Therefore, LsEPSPS was subjected to error-prone PCR to screen mutant EPSPS genes capable of endowing higher resistance levels. A mutant designated as ELs-EPSPS having five mutated amino acids (37Val, 67Asn, 277Ser, 351Gly and 422Gly) was selected for its ability to confer improved resistance to glyphosate. Expression of ELs-EPSPS in recombinant E. coli BL21 (DE3) strains enhanced resistance to glyphosate in comparison to both the LsEPSPS-transformed and -untransformed controls. Furthermore, transgenic ELs-EPSPS A. thaliana was about 5.4 fold and 2-fold resistance to glyphosate compared with the wild-type and the Ls-EPSPS-transgenic plants, respectively. Therefore, the mutated ELs-EPSPS gene has potential value for has potential for the development of glyphosate-resistant crops. Copyright © 2016 Elsevier Inc. All rights reserved.

Molecular recognition of avirulence protein (avrxa5) by eukaryotic transcription factor xa5 of rice (Oryza sativa L.): insights from molecular dynamics simulations.

PubMed

Dehury, Budheswar; Maharana, Jitendra; Sahoo, Bikash Ranjan; Sahu, Jagajjit; Sen, Priyabrata; Modi, Mahendra Kumar; Barooah, Madhumita

2015-04-01

The avirulence gene avrxa5 of bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) recognized by the resistant rice lines having corresponding resistance (xa5) gene in a gene-for-gene manner. We used a combinatorial approach involving protein-protein docking, molecular dynamics (MD) simulations and binding free energy calculations to gain novel insights into the gene-for-gene mechanism that governs the direct interaction of R-Avr protein. From the best three binding poses predicted by molecular docking, MD simulations were performed to explore the dynamic binding mechanism of xa5 and avrxa5. Molecular Mechanics/Poisson Boltzmann Surface Area (MM/PBSA) techniques were employed to calculate the binding free energy and to uncover the thriving force behind the molecular recognition of avrxa5 by eukaryotic transcription factor xa5. Binding free energy analysis revealed van der Waals term as the most constructive component that favors the xa5 and avrxa5 interaction. In addition, hydrogen bonds (H-bonds) and essential electrostatic interactions analysis highlighted amino acid residues Lys54/Asp870, Lys56/Ala868, Lys56/Ala866, Lys56/Glu871, Ile59/His862, Gly61/Phe858, His62/Arg841, His62/Leu856, Ser101/Ala872 and Ser105/Asp870 plays pivotal role for the energetically stability of the R-Avr complex. Insights gained from the present study are expected to unveil the molecular mechanisms that define the transcriptional activator mediated transcriptome modification in host plants. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce

PubMed Central

Simko, Ivan; Atallah, Amy J.; Ochoa, Oswaldo E.; Antonise, Rudie; Galeano, Carlos H.; Truco, Maria Jose; Michelmore, Richard W.

2013-01-01

Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in the 18th and 19th centuries, respectively, have high levels of quantitative resistance to downy mildew. We developed a population of recombinant inbred lines (RILs) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two QTLs for resistance on linkage groups 2 (qDM2.1) and 5 (qDM5.1) that determined resistance under field conditions in California and the Netherlands. The same QTLs determined delayed sporulation at the seedling stage in laboratory experiments. Alleles conferring elevated resistance at both QTLs originate from cultivar Iceberg. An additional QTL on linkage group 9 (qDM9.1) was detected through simultaneous analysis of all experiments with mixed-model approach. Alleles for elevated resistance at this locus originate from cultivar Grand Rapids. PMID:24096732

One gene in diamondback moth confers resistance to four Bacillus thuringiensis toxins

PubMed Central

Tabashnik, Bruce E.; Liu, Yong-Biao; Finson, Naomi; Masson, Luke; Heckel, David G.

1997-01-01

Environmentally benign insecticides derived from the soil bacterium Bacillus thuringiensis (Bt) are the most widely used biopesticides, but their success will be short-lived if pests quickly adapt to them. The risk of evolution of resistance by pests has increased, because transgenic crops producing insecticidal proteins from Bt are being grown commercially. Efforts to delay resistance with two or more Bt toxins assume that independent mutations are required to counter each toxin. Moreover, it generally is assumed that resistance alleles are rare in susceptible populations. We tested these assumptions by conducting single-pair crosses with diamondback moth (Plutella xylostella), the first insect known to have evolved resistance to Bt in open field populations. An autosomal recessive gene conferred extremely high resistance to four Bt toxins (Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F). The finding that 21% of the individuals from a susceptible strain were heterozygous for the multiple-toxin resistance gene implies that the resistance allele frequency was 10 times higher than the most widely cited estimate of the upper limit for the initial frequency of resistance alleles in susceptible populations. These findings suggest that pests may evolve resistance to some groups of toxins much faster than previously expected. PMID:9050831

Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses

DOE PAGES

Schwessinger, Benjamin; Bahar, Ofir; Thomas, Nicolas; ...

2015-03-30

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistancemore » to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.« less

Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses

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

Schwessinger, Benjamin; Bahar, Ofir; Thomas, Nicolas

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistancemore » to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.« less

Vive la résistance: reviving resistance for 21st century conservation.

PubMed

Nimmo, D G; Mac Nally, R; Cunningham, S C; Haslem, A; Bennett, A F

2015-09-01

Confronted with increasing anthropogenic change, conservation in the 21st century requires a sound understanding of how ecological systems change during disturbance. We highlight the benefits of recognizing two distinct components of change in an ecological unit (i.e., ecosystem, community, population): 'resistance', the ability to withstand disturbance; and 'resilience', the capacity to recover following disturbance. By adopting a 'resistance-resilience' framework, important insights for conservation can be gained into: (i) the key role of resistance in response to persistent disturbance, (ii) the intrinsic attributes of an ecological unit associated with resistance and resilience, (iii) the extrinsic environmental factors that influence resistance and resilience, (iv) mechanisms that confer resistance and resilience, (v) the post-disturbance status of an ecological unit, (vi) the nature of long-term ecological changes, and (vii) policy-relevant ways of communicating the ecological impacts of disturbance processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Molecular Mapping and Validation of a Major QTL Conferring Resistance to a Defoliating Isolate of Verticillium Wilt in Cotton (Gossypium hirsutum L.)

PubMed Central

Wei, Ze; Guo, Xian; Guo, Yuping; Zhang, Suqing; Zhao, Junsheng; Zhang, Guihua; Song, Xianliang; Sun, Xuezhen

2014-01-01

Verticillium wilt (VW) caused by Verticillium dahliae Kleb is one of the most destructive diseases of cotton. Development and use of a VW resistant variety is the most practical and effective way to manage this disease. Identification of highly resistant genes/QTL and the underlining genetic architecture is a prerequisite for developing a VW resistant variety. A major QTL qVW-c6-1 conferring resistance to the defoliating isolate V991 was identified on chromosome 6 in LHB22×JM11 F2∶3 population inoculated and grown in a greenhouse. This QTL was further validated in the LHB22×NNG F2∶3 population that was evaluated in an artificial disease nursery of V991 for two years and in its subsequent F4 population grown in a field severely infested by V991. The allele conferring resistance within the QTL qVW-c6-1 region originated from parent LHB22 and could explain 23.1–27.1% of phenotypic variation. Another resistance QTL qVW-c21-1 originated from the susceptible parent JM11 was mapped on chromosome 21, explaining 14.44% of phenotypic variation. The resistance QTL reported herein provides a useful tool for breeding a cotton variety with enhanced resistance to VW. PMID:24781706

Identification of anthranilamide derivatives as potential factor Xa inhibitors: drug design, synthesis and biological evaluation.

PubMed

Xing, Junhao; Yang, Lingyun; Li, Hui; Li, Qing; Zhao, Leilei; Wang, Xinning; Zhang, Yuan; Zhou, Muxing; Zhou, Jinpei; Zhang, Huibin

2015-05-05

The coagulation enzyme factor Xa (fXa) plays a crucial role in the blood coagulation cascade. In this study, three-dimensional fragment based drug design (FBDD) combined with structure-based pharmacophore (SBP) model and structural consensus docking were employed to identify novel fXa inhibitors. After a multi-stage virtual screening (VS) workflow, two hit compounds 3780 and 319 having persistent high performance were identified. Then, these two hit compounds and several analogs were synthesized and screened for in-vitro inhibition of fXa. The experimental data showed that most of the designed compounds displayed significant in vitro potency against fXa. Among them, compound 9b displayed the greatest in vitro potency against fXa with the IC50 value of 23 nM and excellent selectivity versus thrombin (IC50 = 40 μM). Moreover, the prolongation of the prothrombin time (PT) was measured for compound 9b to evaluate its in vitro anticoagulant activity. As a result, compound 9b exhibited pronounced anticoagulant activity with the 2 × PT value of 8.7 μM. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

8 CFR 1003.21 - Pre-hearing conferences and statement.

Code of Federal Regulations, 2010 CFR

2010-01-01

....21 Section 1003.21 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE GENERAL PROVISIONS EXECUTIVE OFFICE FOR IMMIGRATION REVIEW Immigration Court-Rules of Procedure... discretion of the Immigration Judge. The conference may be held to narrow issues, to obtain stipulations...

Transgenic strategies to confer resistance against viruses in rice plants

PubMed Central

Sasaya, Takahide; Nakazono-Nagaoka, Eiko; Saika, Hiroaki; Aoki, Hideyuki; Hiraguri, Akihiro; Netsu, Osamu; Uehara-Ichiki, Tamaki; Onuki, Masatoshi; Toki, Seichi; Saito, Koji; Yatou, Osamu

2014-01-01

Rice (Oryza sativa L.) is cultivated in more than 100 countries and supports nearly half of the world’s population. Developing efficient methods to control rice viruses is thus an urgent necessity because viruses cause serious losses in rice yield. Most rice viruses are transmitted by insect vectors, notably planthoppers and leafhoppers. Viruliferous insect vectors can disperse their viruses over relatively long distances, and eradication of the viruses is very difficult once they become widespread. Exploitation of natural genetic sources of resistance is one of the most effective approaches to protect crops from virus infection; however, only a few naturally occurring rice genes confer resistance against rice viruses. Many investigators are using genetic engineering of rice plants as a potential strategy to control viral diseases. Using viral genes to confer pathogen-derived resistance against crops is a well-established procedure, and the expression of various viral gene products has proved to be effective in preventing or reducing infection by various plant viruses since the 1990s. RNA interference (RNAi), also known as RNA silencing, is one of the most efficient methods to confer resistance against plant viruses on their respective crops. In this article, we review the recent progress, mainly conducted by our research group, in transgenic strategies to confer resistance against tenuiviruses and reoviruses in rice plants. Our findings also illustrate that not all RNAi constructs against viral RNAs are equally effective in preventing virus infection and that it is important to identify the viral “Achilles’ heel” gene to target for RNAi attack when engineering plants. PMID:24454308

Transcriptomic Analysis and the Expression of Disease-Resistant Genes in Oryza meyeriana under Native Condition

PubMed Central

He, Bin; Tao, Xiang; Gu, Yinghong; Wei, Changhe; Cheng, Xiaojie; Xiao, Suqin; Cheng, Zaiquan; Zhang, Yizheng

2015-01-01

Oryza meyeriana (O. meyeriana), with a GG genome type (2n = 24), accumulated plentiful excellent characteristics with respect to resistance to many diseases such as rice shade and blast, even immunity to bacterial blight. It is very important to know if the diseases-resistant genes exist and express in this wild rice under native conditions. However, limited genomic or transcriptomic data of O. meyeriana are currently available. In this study, we present the first comprehensive characterization of the O. meyeriana transcriptome using RNA-seq and obtained 185,323 contigs with an average length of 1,692 bp and an N50 of 2,391 bp. Through differential expression analysis, it was found that there were most tissue-specifically expressed genes in roots, and next to stems and leaves. By similarity search against protein databases, 146,450 had at least a significant alignment to existed gene models. Comparison with the Oryza sativa (japonica-type Nipponbare and indica-type 93–11) genomes revealed that 13% of the O. meyeriana contigs had not been detected in O. sativa. Many diseases-resistant genes, such as bacterial blight resistant, blast resistant, rust resistant, fusarium resistant, cyst nematode resistant and downy mildew gene, were mined from the transcriptomic database. There are two kinds of rice bacterial blight-resistant genes (Xa1 and Xa26) differentially or specifically expressed in O. meyeriana. The 4 Xa1 contigs were all only expressed in root, while three of Xa26 contigs have the highest expression level in leaves, two of Xa26 contigs have the highest expression profile in stems and one of Xa26 contigs was expressed dominantly in roots. The transcriptomic database of O. meyeriana has been constructed and many diseases-resistant genes were found to express under native condition, which provides a foundation for future discovery of a number of novel genes and provides a basis for studying the molecular mechanisms associated with disease resistance in O

Chemoenzymatic Synthesis of Heparin Oligosaccharides with both Anti-factor Xa and Anti-factor IIa Activities*

PubMed Central

Xu, Yongmei; Pempe, Elizabeth H.; Liu, Jian

2012-01-01

Heparan sulfate (HS) and heparin are highly sulfated polysaccharides. Heparin is a commonly used anticoagulant drug that inhibits the activities of factors Xa and IIa (also known as thrombin) to prevent blood clot formation. Here, we report the synthesis of a series of size-defined oligosaccharides to probe the minimum size requirement for an oligosaccharide with anti-IIa activity. The synthesis was completed by a chemoenzymatic approach involving glycosyltransferases, HS sulfotransferases, and C5-epimerase. We demonstrate the ability to synthesize highly purified N-sulfo-oligosaccharides having up to 21 saccharide residues. The results from anti-Xa and anti-IIa activity measurements revealed that an oligosaccharide longer than 19 saccharide residues is necessary to display anti-IIa activity. The oligosaccharides also exhibit low binding toward platelet factor 4, raising the possibility of preparing a synthetic heparin with a reduced effect of heparin-induced thrombocytopenia. The results from this study demonstrate the ability to synthesize large HS oligosaccharides and provide a unique tool to probe the structure and function relationships of HS that require the use of large HS fragments. PMID:22773834

Quantitative genome re-sequencing defines multiple mutations conferring chloroquine resistance in rodent malaria

PubMed Central

2012-01-01

Background Drug resistance in the malaria parasite Plasmodium falciparum severely compromises the treatment and control of malaria. A knowledge of the critical mutations conferring resistance to particular drugs is important in understanding modes of drug action and mechanisms of resistances. They are required to design better therapies and limit drug resistance. A mutation in the gene (pfcrt) encoding a membrane transporter has been identified as a principal determinant of chloroquine resistance in P. falciparum, but we lack a full account of higher level chloroquine resistance. Furthermore, the determinants of resistance in the other major human malaria parasite, P. vivax, are not known. To address these questions, we investigated the genetic basis of chloroquine resistance in an isogenic lineage of rodent malaria parasite P. chabaudi in which high level resistance to chloroquine has been progressively selected under laboratory conditions. Results Loci containing the critical genes were mapped by Linkage Group Selection, using a genetic cross between the high-level chloroquine-resistant mutant and a genetically distinct sensitive strain. A novel high-resolution quantitative whole-genome re-sequencing approach was used to reveal three regions of selection on chr11, chr03 and chr02 that appear progressively at increasing drug doses on three chromosomes. Whole-genome sequencing of the chloroquine-resistant parent identified just four point mutations in different genes on these chromosomes. Three mutations are located at the foci of the selection valleys and are therefore predicted to confer different levels of chloroquine resistance. The critical mutation conferring the first level of chloroquine resistance is found in aat1, a putative aminoacid transporter. Conclusions Quantitative trait loci conferring selectable phenotypes, such as drug resistance, can be mapped directly using progressive genome-wide linkage group selection. Quantitative genome-wide short

Materials Testing on the DC-X and DC-XA

NASA Technical Reports Server (NTRS)

Smith, Dane; Carroll, Carol; Marschall, Jochen; Pallix, Joan

1997-01-01

Flight testing of thermal protection materials has been carried out over a two year period on the base heat shield of the Delta Clipper (DC-X and DC-XA), as well on a body flap. The purpose was to use the vehicle as a test bed for materials and more efficient repair or maintenance processes which would be potentially useful for application on new entry vehicles (i.e., X-33, RLV, planetary probes), as well as on the existing space shuttle orbiters. Panels containing Thermal Protection Systems (TPS) and/or structural materials were constructed either at NASA Ames Research Center or at McDonnell Douglas Aerospace (MDA) and attached between two of the four thrusters in the base heat shield of the DC-X or DC-XA. Three different panels were flown on DC-X flights 6, 7, and 8. A total of 7 panels were flown on DC-XA flights 1, 2, and 3. The panels constructed at Ames contained a variety of ceramic TPS including flexible blankets, tiles with high emissivity coatings, lightweight ceramic ablators and other ceramic composites. The MDS test panels consisted primarily of a variety of metallic composites. This report focuses on the ceramic TPS test results.

ERK Mutations Confer Resistance to Mitogen-Activated Protein Kinase Pathway Inhibitors

PubMed Central

Goetz, Eva M.; Ghandi, Mahmoud; Treacy, Daniel J.; Wagle, Nikhil; Garraway, Levi A.

2015-01-01

The use of targeted therapeutics directed against BRAFV600-mutant metastatic melanoma improves progression-free survival in many patients; however, acquired drug resistance remains a major medical challenge. By far, the most common clinical resistance mechanism involves reactivation of the MAPK (RAF/MEK/ERK) pathway by a variety of mechanisms. Thus, targeting ERK itself has emerged as an attractive therapeutic concept, and several ERK inhibitors have entered clinical trials. We sought to preemptively determine mutations in ERK1/2 that confer resistance to either ERK inhibitors or combined RAF/MEK inhibition in BRAFV600-mutant melanoma. Using a random mutagenesis screen, we identified multiple point mutations in ERK1 (MAPK3) and ERK2 (MAPK1) that could confer resistance to ERK or RAF/MEK inhibitors. ERK inhibitor–resistant alleles were sensitive to RAF/ MEK inhibitors and vice versa, suggesting that the future development of alternating RAF/MEK and ERK inhibitor regimens might help circumvent resistance to these agents. PMID:25320010

Discovery of a tetrahydropyrimidin-2(1H)-one derivative (TAK-442) as a potent, selective, and orally active factor Xa inhibitor.

PubMed

Fujimoto, Takuya; Imaeda, Yasuhiro; Konishi, Noriko; Hiroe, Katsuhiko; Kawamura, Masaki; Textor, Garret P; Aertgeerts, Kathleen; Kubo, Keiji

2010-05-13

Coagulation enzyme factor Xa (FXa) is a particularly promising target for the development of new anticoagulant agents. We previously reported the imidazo[1,5-c]imidazol-3-one derivative 1 as a potent and orally active FXa inhibitor. However, it was found that 1 predominantly undergoes hydrolysis upon incubation with human liver microsomes, and the human specific metabolic pathway made it difficult to predict the human pharmacokinetics. To address this issue, our synthetic efforts were focused on modification of the imidazo[1,5-c]imidazol-3-one moiety of the active metabolite 3a, derived from 1, which resulted in the discovery of the tetrahydropyrimidin-2(1H)-one derivative 5k as a highly potent and selective FXa inhibitor. Compound 5k showed no detectable amide bond cleavage in human liver microsomes, exhibited a good pharmacokinetic profile in monkeys, and had a potent antithrombotic efficacy in a rabbit model without prolongation of bleeding time. Compound 5k is currently under clinical development with the code name TAK-442.

Mutation of environmental mycobacteria to resist silver nanoparticles also confers resistance to a common antibiotic.

PubMed

Larimer, Curtis; Islam, Mohammad Shyful; Ojha, Anil; Nettleship, Ian

2014-08-01

Non-tuberculous mycobacteria are a threat to human health, gaining entry to the body through contaminated water systems, where they form persistent biofilms despite extensive attempts at disinfection. Silver is a natural antibacterial agent and in nanoparticle form activity is increased by a high surface area. Silver nanoparticles (AgNPs) have been used as alternative disinfectants in circulating water systems, washing machines and even clothing. However, nanoparticles, like any other antibiotic that has a pervasive durable presence, carry the risk of creating a resistant population. In this study Mycobacterium smegmatis strain mc(2)155 was cultured in AgNP enriched agar such that only a small population survived. Surviving cultures were isolated and re-exposed to AgNPs and AgNO3 and resistance to silver was compared to a negative control. After only a single exposure, mutant M. smegmatis populations were resistant to AgNPs and AgNO3. Further, the silver resistant mutants were exposed to antibiotics to determine if general resistance had been conferred. The minimum inhibitory concentration of isoniazid was four times higher for silver resistant mutants than for strain mc(2)155. However, core resistance was not conferred to other toxic metal ions. The mutants had lower resistance to CuSO4 and ZnSO4 than the mc(2)155 strain.

Homologues of a single resistance-gene cluster in potato confer resistance to distinct pathogens: a virus and a nematode.

PubMed

van der Vossen, E A; van der Voort, J N; Kanyuka, K; Bendahmane, A; Sandbrink, H; Baulcombe, D C; Bakker, J; Stiekema, W J; Klein-Lankhorst, R M

2000-09-01

The isolation of the nematode-resistance gene Gpa2 in potato is described, and it is demonstrated that highly homologous resistance genes of a single resistance-gene cluster can confer resistance to distinct pathogen species. Molecular analysis of the Gpa2 locus resulted in the identification of an R-gene cluster of four highly homologous genes in a region of approximately 115 kb. At least two of these genes are active: one corresponds to the previously isolated Rx1 gene that confers resistance to potato virus X, while the other corresponds to the Gpa2 gene that confers resistance to the potato cyst nematode Globodera pallida. The proteins encoded by the Gpa2 and the Rx1 genes share an overall homology of over 88% (amino-acid identity) and belong to the leucine-zipper, nucleotide-binding site, leucine-rich repeat (LZ-NBS-LRR)-containing class of plant resistance genes. From the sequence conservation between Gpa2 and Rx1 it is clear that there is a direct evolutionary relationship between the two proteins. Sequence diversity is concentrated in the LRR region and in the C-terminus. The putative effector domains are more conserved suggesting that, at least in this case, nematode and virus resistance cascades could share common components. These findings underline the potential of protein breeding for engineering new resistance specificities against plant pathogens in vitro.

DOUGLAS XA3D-1 #413 AIRPLANE.

NASA Image and Video Library

1955-07-27

DOUGLAS XA3D-1 #413 AIRPLANE MOUNTED IN THE NACA AMES RESEARCH CENTER'S 40X80_FOOT SUBSONIC WIND TUNNEL Testing the boundary layer control of the A3D in the 40 x 80 wind tunnel. Boundary layer control was added to increase the lift of the wing for take off from an aircraft carrier.

ERK mutations confer resistance to mitogen-activated protein kinase pathway inhibitors.

PubMed

Goetz, Eva M; Ghandi, Mahmoud; Treacy, Daniel J; Wagle, Nikhil; Garraway, Levi A

2014-12-01

The use of targeted therapeutics directed against BRAF(V600)-mutant metastatic melanoma improves progression-free survival in many patients; however, acquired drug resistance remains a major medical challenge. By far, the most common clinical resistance mechanism involves reactivation of the MAPK (RAF/MEK/ERK) pathway by a variety of mechanisms. Thus, targeting ERK itself has emerged as an attractive therapeutic concept, and several ERK inhibitors have entered clinical trials. We sought to preemptively determine mutations in ERK1/2 that confer resistance to either ERK inhibitors or combined RAF/MEK inhibition in BRAF(V600)-mutant melanoma. Using a random mutagenesis screen, we identified multiple point mutations in ERK1 (MAPK3) and ERK2 (MAPK1) that could confer resistance to ERK or RAF/MEK inhibitors. ERK inhibitor-resistant alleles were sensitive to RAF/MEK inhibitors and vice versa, suggesting that the future development of alternating RAF/MEK and ERK inhibitor regimens might help circumvent resistance to these agents. ©2014 American Association for Cancer Research.

Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery.

PubMed

Dharmasena, Madushini N; Feuille, Catherine M; Starke, Carly Elizabeth C; Bhagwat, Arvind A; Stibitz, Scott; Kopecko, Dennis J

The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues. However, the ECC was selected as a more practical delivery format for both packaging/shipping and vaccine administration ease. We have sought to increase Ty21a acid-resistance to allow for removal from the ECC and immune enhancement. To improve Ty21a acid-resistance, glutamate-dependent acid resistance genes (GAD; responsible for Shigella spp. survival at very low pH) were cloned on a multi-copy plasmid (pGad) under a controllable arabinose-inducible promoter. pGad enhanced acid survival of Ty21a by 5 logs after 3 hours at pH 2.5, when cells were pre-grown in arabinose and under conditions that promote an acid-tolerance response (ATR). For genetically 100% stable expression, we inserted the gad genes into the Ty21a chromosome, using a method that allowed for subsequent removal of a selectable antibiotic resistance marker. Further, both bacterial growth curves and survival assays in cultured human monocytes/macrophages suggest that neither the genetic methods employed nor the resulting acid-resistance conferred by expression of the Gad proteins in Ty21a had any effect on the existing attenuation of this vaccine strain.

DOUGLAS XA3D-1 #413 AIRPLANE.

NASA Image and Video Library

1955-07-27

DOUGLAS XA3D-1 #413 AIRPLANE MOUNTED IN THE NACA AMES RESEARCH CENTER'S 40X80_FOOT SUBSONIC WIND TUNNEL sweptback wing Testing the wing boundary layer control of the A3D in the 40 x 80 wind tunnel. Boundary layer control was added to increase the lift of the wing for aircraft carrier take off and landing.

Impact damage resistance of carbon/epoxy composite tubes for the DC-XA liquid hydrogen feedline

NASA Technical Reports Server (NTRS)

Nettles, A. T.

1995-01-01

Low-velocity impacts were inflicted upon two elbow sections of carbon/epoxy feedline that are to be a part of the Delta Clipper-XA flight vehicle. A soap-based liquid leak detector solution was used to inspect the impact sites for leaks of pressurized gas that was pumped into the tube. Visual surface damage was noted and recorded for each impact site. After impact testing of each of the two sections of tubes was completed, the damage zones were disected from the tube and cross sectioned through the impact site. These specimens were polished after potting them in epoxy and were examined for microcracking using a fluorescent dye penetrant technique. The results showed that nonvisible damage could cause microcracking, thereby resulting in leaks through the tube wall.

The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response

PubMed Central

Ronald, Pamela C.

2014-01-01

Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB). These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS. PMID:25386383

The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response.

PubMed

Ronald, Pamela C

2014-01-01

Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB). These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.

Influence of apixaban on antifactor Xa levels in a patient with acute kidney injury.

PubMed

Wendte, Jodi; Voss, Glenn; VanOverschelde, Beau

2016-04-15

The case of a patient requiring conversion from apixaban to heparin in the setting of acute kidney injury is reported. A 70-year-old man was initiated on apixaban 5 mg twice daily for new-onset, nonvalvular atrial fibrillation with a CHA2DS2-VASc score of 4, indicating a high risk of stroke. Soon after starting apixaban, he experienced pulmonary edema with pneumonia requiring hospitalization. During the course of hospitalization, the patient developed acute kidney injury requiring hemodialysis, and apixaban was stopped due to concerns about altered pharmacokinetics and impaired drug elimination in this setting. A heparin infusion was started 36 hours after the last dose of apixaban was administered. Antifactor Xa levels were monitored consistent with the hospital's standard practice protocols. The initial and repeat antifactor Xa concentrations were elevated (1.8-4.4 IU/mL) for up 72 hours after stopping the heparin infusion. Given the suspected interference of apixaban with standard antifactor Xa level monitoring, the heparin protocol was modified to reflect drip-rate adjustments based on activated partial thromboplastin times (aPTTs). The hospital protocol for heparin infusions was reinstituted on hospital day 7, with dosage adjustments based on antifactor Xa levels. The patient remained on a continuous heparin infusion for atrial fibrillation for the remainder of his hospitalization without complications or bleeding events. A 70-year-old man with new-onset nonvalvular atrial fibrillation and receiving apixaban discontinued this therapy and was given heparin instead due to acute kidney injury. His heparin dosage was successfully adjusted based on antifactor Xa levels and aPPTs. Copyright © 2016 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Foliar resistance to fall armyworm in corn germplasm lines that confer resistance to root- and ear-feeding insects

USDA-ARS?s Scientific Manuscript database

A holistic approach to developing new corn germplasm that confers multiple insect resistance in various plant tissues at different growth stages was examined. Eight corn germplasm lines were examined for their foliage resistance to fall armyworm [Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noc...

3D/3D registration of coronary CTA and biplane XA reconstructions for improved image guidance

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

Dibildox, Gerardo, E-mail: g.dibildox@erasmusmc.nl; Baka, Nora; Walsum, Theo van

2014-09-15

Purpose: The authors aim to improve image guidance during percutaneous coronary interventions of chronic total occlusions (CTO) by providing information obtained from computed tomography angiography (CTA) to the cardiac interventionist. To this end, the authors investigate a method to register a 3D CTA model to biplane reconstructions. Methods: The authors developed a method for registering preoperative coronary CTA with intraoperative biplane x-ray angiography (XA) images via 3D models of the coronary arteries. The models are extracted from the CTA and biplane XA images, and are temporally aligned based on CTA reconstruction phase and XA ECG signals. Rigid spatial alignment ismore » achieved with a robust probabilistic point set registration approach using Gaussian mixture models (GMMs). This approach is extended by including orientation in the Gaussian mixtures and by weighting bifurcation points. The method is evaluated on retrospectively acquired coronary CTA datasets of 23 CTO patients for which biplane XA images are available. Results: The Gaussian mixture model approach achieved a median registration accuracy of 1.7 mm. The extended GMM approach including orientation was not significantly different (P > 0.1) but did improve robustness with regards to the initialization of the 3D models. Conclusions: The authors demonstrated that the GMM approach can effectively be applied to register CTA to biplane XA images for the purpose of improving image guidance in percutaneous coronary interventions.« less

Proceedings from the Texas Rural Transportation Conference Transportation and Tourism Track : February 21, 2001 : George Bush Presidential Conference Center, College Station, Texas

DOT National Transportation Integrated Search

2001-07-01

This report documents the proceedings from the Transportation and Tourism Track at the Texas Rural Transportation Conference held in College Station, Texas on February 21, 2000. The Conference was : sponsored by the Texas Transportation Institute, th...

Glutathione S-transferases as antioxidant defence agents confer pyrethroid resistance in Nilaparvata lugens.

PubMed Central

Vontas, J G; Small, G J; Hemingway, J

2001-01-01

Selection of a laboratory colony of the brown planthopper Nilaparvata lugens with the pyrethroids permethrin and lambda-cyhalothrin increased its resistance to both insecticides. Biochemical analysis and synergistic studies with metabolic inhibitors indicated that elevated glutathione S-transferases (GSTs) with a predominant peroxidase activity conferred resistance to both pyrethroids, whereas esterases conferred part of the resistance to permethrin. Purified esterases hydrolysed permethrin at a slow rate, but incubation of either pyrethroid or their primary metabolites with partially purified GSTs had no effect on the metabolic profile. Although GSTs were sensitive to inhibition by both pyrethroids, they did not serve as binding proteins, as previously hypothesized [Grant and Matsumura (1988) Insect Biochem. 18, 615-622]. We demonstrate that pyrethroids, in addition to their neurotoxic effect, induce oxidative stress and lipid peroxidation in insects. Pyrethroid exposure induced lipid peroxides, protein oxidation and depleted reduced glutathione. Elevated GSTs in the resistant strains attenuated the pyrethroid-induced lipid peroxidation and reduced mortality, whereas their in vivo inhibition eliminated their protective role. We therefore hypothesize that the main role of elevated GSTs in conferring resistance in N. lugens is through protecting tissues from oxidative damage. Our study extends the GSTs' range of efficacy to pyrethroid insecticides and possibly explains the role of elevated GSTs in other pyrethroid-resistant insects. PMID:11415437

Revisiting the X:A signal that specifies Caenorhabditis elegans sexual fate.

PubMed

Gladden, John M; Farboud, Behnom; Meyer, Barbara J

2007-11-01

In Caenorhabditis elegans, sex is determined by the opposing actions of X-signal elements (XSEs) and autosomal signal elements (ASEs), which communicate the ratio of X chromosomes to sets of autosomes (X:A signal). This study delves more deeply into the mechanism by which XSEs transmit X chromosome dose. We determined the relative contributions of individual XSEs to the X:A signal and showed the order of XSE strength to be sex-1 > sex-2 > fox-1 > ceh-39 >/= region 1 XSE. sex-1 exerts a more potent influence on sex determination and dosage compensation than any other XSE by functioning in two separate capacities in the pathway: sex-1 acts upstream as an XSE to repress xol-1 and downstream as an activator of hermaphrodite development and dosage compensation. Furthermore, the process of dosage compensation affects expression of the very XSEs that control it; XSEs become fully dosage compensated once sex is determined. The X:A signal is then equivalent between XO and XX animals, causing sexual differentiation to be controlled by genes downstream of xol-1 in the sex-determination pathway. Prior to the onset of dosage compensation, the difference in XSE expression between XX and XO embryos appears to be greater than twofold, making X chromosome counting a robust process.

Naturally selected hepatitis C virus polymorphisms confer broad neutralizing antibody resistance.

PubMed

Bailey, Justin R; Wasilewski, Lisa N; Snider, Anna E; El-Diwany, Ramy; Osburn, William O; Keck, Zhenyong; Foung, Steven K H; Ray, Stuart C

2015-01-01

For hepatitis C virus (HCV) and other highly variable viruses, broadly neutralizing mAbs are an important guide for vaccine development. The development of resistance to anti-HCV mAbs is poorly understood, in part due to a lack of neutralization testing against diverse, representative panels of HCV variants. Here, we developed a neutralization panel expressing diverse, naturally occurring HCV envelopes (E1E2s) and used this panel to characterize neutralizing breadth and resistance mechanisms of 18 previously described broadly neutralizing anti-HCV human mAbs. The observed mAb resistance could not be attributed to polymorphisms in E1E2 at known mAb-binding residues. Additionally, hierarchical clustering analysis of neutralization resistance patterns revealed relationships between mAbs that were not predicted by prior epitope mapping, identifying 3 distinct neutralization clusters. Using this clustering analysis and envelope sequence data, we identified polymorphisms in E2 that confer resistance to multiple broadly neutralizing mAbs. These polymorphisms, which are not at mAb contact residues, also conferred resistance to neutralization by plasma from HCV-infected subjects. Together, our method of neutralization clustering with sequence analysis reveals that polymorphisms at noncontact residues may be a major immune evasion mechanism for HCV, facilitating viral persistence and presenting a challenge for HCV vaccine development.

Phenotyping of VIGS-mediated gene silencing in rice using a vector derived from a DNA virus.

PubMed

Kant, Ravi; Dasgupta, Indranil

2017-07-01

Target genes in rice can be optimally silenced if inserted in antisense or hairpin orientation in the RTBV-derived VIGS vector and plants grown at 28 °C and 80% humidity after inoculation. Virus induced gene silencing (VIGS) is a method used to transiently silence genes in dicot as well as monocot plants. For the important monocot species rice, the Rice tungro bacilliform virus (RTBV)-derived VIGS system (RTBV-VIGS), which uses agroinoculation to initiate silencing, has not been standardized for optimal use. Here, using RTBV-VIGS, three sets of conditions were tested to achieve optimal silencing of the rice marker gene phytoene desaturase (pds). The effect of orientation of the insert in the RTBV-VIGS plasmid (sense, antisense and hairpin) on the silencing of the target gene was then evaluated using rice magnesium chelatase subunit H (chlH). Finally, the rice Xa21 gene, conferring resistance against bacterial leaf blight disease (BLB) was silenced using RTBV-VIGS system. In each case, real-time PCR-based assessment indicated approximately 40-80% fall in the accumulation levels of the transcripts of pds, chlH and Xa21. In the case of pds, the appearance of white streaks in the emerging leaves, and for chlH, chlorophyll levels and F v /F m ratio were assessed as phenotypes for silencing. For Xa21, the resistance levels to BLB were assessed by measuring the lesion length and the percent diseased areas of leaves, following challenge inoculation with Xanthomonas oryzae. In each case, the RTBV-MVIGS system gave rise to a discernible phenotype indicating the silencing of the respective target gene using condition III (temperature 28 °C, humidity 80% and 1 mM MES and 20 µM acetosyringone in secondary agrobacterium culture), which revealed the robustness of this gene silencing system for rice.

Developing an Anti-Xa-Based Anticoagulation Protocol for Patients with Percutaneous Ventricular Assist Devices.

PubMed

Sieg, Adam; Mardis, B Andrew; Mardis, Caitlin R; Huber, Michelle R; New, James P; Meadows, Holly B; Cook, Jennifer L; Toole, J Matthew; Uber, Walter E

2015-01-01

Because of the complexities associated with anticoagulation in temporary percutaneous ventricular assist device (pVAD) recipients, a lack of standardization exists in their management. This retrospective analysis evaluates current anticoagulation practices at a single center with the aim of identifying an optimal anticoagulation strategy and protocol. Patients were divided into two cohorts based on pVAD implanted (CentriMag (Thoratec; Pleasanton, CA) / TandemHeart (CardiacAssist; Pittsburgh, PA) or Impella (Abiomed, Danvers, MA)), with each group individually analyzed for bleeding and thrombotic complications. Patients in the CentriMag/TandemHeart cohort were subdivided based on the anticoagulation monitoring strategy (activated partial thromboplastin time (aPTT) or antifactor Xa unfractionated heparin (anti-Xa) values). In the CentriMag/TandemHeart cohort, there were five patients with anticoagulation titrated based on anti-Xa values; one patient developed a device thrombosis and a major bleed, whereas another patient experienced major bleeding. Eight patients received an Impella pVAD. Seven total major bleeds in three patients and no thrombotic events were detected. Based on distinct differences between the devices, anti-Xa values, and outcomes, two protocols were created to guide anticoagulation adjustments. However, anticoagulation in patients who require pVAD support is complex with constantly evolving anticoagulation goals. The ideal level of anticoagulation should be individually determined using several coagulation laboratory parameters in concert with hemodynamic changes in the patient's clinical status, the device, and the device cannulation.

BCR-ABL1 Compound Mutations Combining Key Kinase Domain Positions Confer Clinical Resistance to Ponatinib in Ph Chromosome-Positive Leukemia

PubMed Central

Zabriskie, Matthew S.; Eide, Christopher A.; Tantravahi, Srinivas K.; Vellore, Nadeem A.; Estrada, Johanna; Nicolini, Franck E.; Khoury, Hanna J.; Larson, Richard A.; Konopleva, Marina; Cortes, Jorge E.; Kantarjian, Hagop; Jabbour, Elias J.; Kornblau, Steven M.; Lipton, Jeffrey H.; Rea, Delphine; Stenke, Leif; Barbany, Gisela; Lange, Thoralf; Hernández-Boluda, Juan-Carlos; Ossenkoppele, Gert J.; Press, Richard D.; Chuah, Charles; Goldberg, Stuart L.; Wetzler, Meir; Mahon, Francois-Xavier; Etienne, Gabriel; Baccarani, Michele; Soverini, Simona; Rosti, Gianantonio; Rousselot, Philippe; Friedman, Ran; Deininger, Marie; Reynolds, Kimberly R.; Heaton, William L.; Eiring, Anna M.; Pomicter, Anthony D.; Khorashad, Jamshid S.; Kelley, Todd W.; Baron, Riccardo; Druker, Brian J.; Deininger, Michael W.; O'Hare, Thomas

2014-01-01

Summary Ponatinib is the only currently approved tyrosine kinase inhibitor (TKI) that suppresses all BCR-ABL1 single mutants in Philadelphia chromosome-positive (Ph+) leukemia, including the recalcitrant BCR-ABL1T315I mutant. However, emergence of compound mutations in a BCR-ABL1 allele may confer ponatinib resistance. We found that clinically reported BCR-ABL1 compound mutants center on 12 key positions and confer varying resistance to imatinib, nilotinib, dasatinib, ponatinib, rebastinib and bosutinib. T315I-inclusive compound mutants confer high-level resistance to TKIs, including ponatinib. In vitro resistance profiling was predictive of treatment outcomes in Ph+ leukemia patients. Structural explanations for compound mutation-based resistance were obtained through molecular dynamics simulations. Our findings demonstrate that BCR-ABL1 compound mutants confer different levels of TKI resistance, necessitating rational treatment selection to optimize clinical outcome. PMID:25132497

Residual Enoxaparin Activity, Anti-Xa Levels, and Concerns About the American Society of Regional Anesthesia and Pain Medicine Anticoagulation Guidelines.

PubMed

Henshaw, Daryl S; Turner, James D; Forest, Daniel J; Thompson, Garrett R; Weller, Robert S

Currently, the American Society of Regional Anesthesia and Pain Medicine (ASRA) anticoagulation guidelines recommend that before the performance of a neuraxial procedure a minimum of 24 hours should elapse following a treatment dose of enoxaparin (1 mg/kg twice daily or 1.5 mg/kg once daily). The guidelines have since their inception also consistently recommended against the routine use of anti-Xa level monitoring for patients receiving enoxaparin. However, we noted in our clinical practice that anti-Xa levels were frequently still elevated despite patients meeting the time-based recommendation for treatment dose enoxaparin. To further investigate the possibility that residual anticoagulant activity may persist longer than 24 hours after a treatment dose of enoxaparin, we assessed anti-Xa level activity in patients presenting for elective surgery. Despite nearly universal compliance with ASRA's anticoagulation guidelines (1 sample was drawn at 23.25 hours), anti-Xa activity was found to be elevated in 11 of 19 patients. While 10 patients had an anti-Xa level within the peak prophylactic range (0.2-0.5 IU/mL), 1 patient's level was found to still be in the peak therapeutic range (0.5-1.0 IU/mL). These findings suggest that significant anticoagulant activity may persist longer than previously appreciated after the last treatment dose of enoxaparin and that the current time-based ASRA recommendation may not be conservative enough. Further research is needed to delineate the level of anti-Xa activity below which it is likely safe to proceed with a neuraxial procedure, but it may be time to reconsider the utility of anti-Xa level monitoring when it is available.

A horizontally gene transferred copper resistance locus confers hyper‐resistance to antibacterial copper toxicity and enables survival of community acquired methicillin resistant Staphylococcus aureus USA300 in macrophages

PubMed Central

Purves, Joanne; Thomas, Jamie; Riboldi, Gustavo P.; Zapotoczna, Marta; Tarrant, Emma; Andrew, Peter W.; Londoño, Alejandra; Planet, Paul J.; Geoghegan, Joan A.; Waldron, Kevin J.

2018-01-01

Summary Excess copper is highly toxic and forms part of the host innate immune system's antibacterial arsenal, accumulating at sites of infection and acting within macrophages to kill engulfed pathogens. We show for the first time that a novel, horizontally gene transferred copper resistance locus (copXL), uniquely associated with the SCCmec elements of the highly virulent, epidemic, community acquired methicillin resistant Staphylococcus aureus (CA‐MRSA) USA300, confers copper hyper‐resistance. These genes are additional to existing core genome copper resistance mechanisms, and are not found in typical S. aureus lineages, but are increasingly identified in emerging pathogenic isolates. Our data show that CopX, a putative P1B‐3‐ATPase efflux transporter, and CopL, a novel lipoprotein, confer copper hyper‐resistance compared to typical S. aureus strains. The copXL genes form an operon that is tightly repressed in low copper environments by the copper regulator CsoR. Significantly, CopX and CopL are important for S. aureus USA300 intracellular survival within macrophages. Therefore, the emergence of new S. aureus clones with the copXL locus has significant implications for public health because these genes confer increased resistance to antibacterial copper toxicity, enhancing bacterial fitness by altering S. aureus interaction with innate immunity. PMID:29521441

BCR-ABL1 compound mutations combining key kinase domain positions confer clinical resistance to ponatinib in Ph chromosome-positive leukemia.

PubMed

Zabriskie, Matthew S; Eide, Christopher A; Tantravahi, Srinivas K; Vellore, Nadeem A; Estrada, Johanna; Nicolini, Franck E; Khoury, Hanna J; Larson, Richard A; Konopleva, Marina; Cortes, Jorge E; Kantarjian, Hagop; Jabbour, Elias J; Kornblau, Steven M; Lipton, Jeffrey H; Rea, Delphine; Stenke, Leif; Barbany, Gisela; Lange, Thoralf; Hernández-Boluda, Juan-Carlos; Ossenkoppele, Gert J; Press, Richard D; Chuah, Charles; Goldberg, Stuart L; Wetzler, Meir; Mahon, Francois-Xavier; Etienne, Gabriel; Baccarani, Michele; Soverini, Simona; Rosti, Gianantonio; Rousselot, Philippe; Friedman, Ran; Deininger, Marie; Reynolds, Kimberly R; Heaton, William L; Eiring, Anna M; Pomicter, Anthony D; Khorashad, Jamshid S; Kelley, Todd W; Baron, Riccardo; Druker, Brian J; Deininger, Michael W; O'Hare, Thomas

2014-09-08

Ponatinib is the only currently approved tyrosine kinase inhibitor (TKI) that suppresses all BCR-ABL1 single mutants in Philadelphia chromosome-positive (Ph(+)) leukemia, including the recalcitrant BCR-ABL1(T315I) mutant. However, emergence of compound mutations in a BCR-ABL1 allele may confer ponatinib resistance. We found that clinically reported BCR-ABL1 compound mutants center on 12 key positions and confer varying resistance to imatinib, nilotinib, dasatinib, ponatinib, rebastinib, and bosutinib. T315I-inclusive compound mutants confer high-level resistance to TKIs, including ponatinib. In vitro resistance profiling was predictive of treatment outcomes in Ph(+) leukemia patients. Structural explanations for compound mutation-based resistance were obtained through molecular dynamics simulations. Our findings demonstrate that BCR-ABL1 compound mutants confer different levels of TKI resistance, necessitating rational treatment selection to optimize clinical outcome. Copyright © 2014 Elsevier Inc. All rights reserved.

21 CFR 516.123 - Informal conferences regarding agency administrative actions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... exemption, determining that a qualified expert panel does not meet the selection criteria, denying a request... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Informal conferences regarding agency administrative actions. 516.123 Section 516.123 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH...

Loss of function of a rice TPR-domain RNA-binding protein confers broad-spectrum disease resistance.

PubMed

Zhou, Xiaogang; Liao, Haicheng; Chern, Mawsheng; Yin, Junjie; Chen, Yufei; Wang, Jianping; Zhu, Xiaobo; Chen, Zhixiong; Yuan, Can; Zhao, Wen; Wang, Jing; Li, Weitao; He, Min; Ma, Bingtian; Wang, Jichun; Qin, Peng; Chen, Weilan; Wang, Yuping; Liu, Jiali; Qian, Yangwen; Wang, Wenming; Wu, Xianjun; Li, Ping; Zhu, Lihuang; Li, Shigui; Ronald, Pamela C; Chen, Xuewei

2018-03-20

Crops carrying broad-spectrum resistance loci provide an effective strategy for controlling infectious disease because these loci typically confer resistance to diverse races of a pathogen or even multiple species of pathogens. Despite their importance, only a few crop broad-spectrum resistance loci have been reported. Here, we report the identification and characterization of the rice bsr-k1 (broad-spectrum resistance Kitaake-1) mutant, which confers broad-spectrum resistance against Magnaporthe oryzae and Xanthomonas oryzae pv oryzae with no major penalty on key agronomic traits. Map-based cloning reveals that Bsr-k1 encodes a tetratricopeptide repeats (TPRs)-containing protein, which binds to mRNAs of multiple OsPAL ( OsPAL1-7 ) genes and promotes their turnover. Loss of function of the Bsr-k1 gene leads to accumulation of OsPAL1-7 mRNAs in the bsr-k1 mutant. Furthermore, overexpression of OsPAL1 in wild-type rice TP309 confers resistance to M. oryzae , supporting the role of OsPAL1 Our discovery of the bsr-k1 allele constitutes a significant conceptual advancement and provides a valuable tool for breeding broad-spectrum resistant rice. Copyright © 2018 the Author(s). Published by PNAS.

Characterization and expression analysis of two cDNAs encoding Xa1 and oxysterol binding proteins in sorghum (Sorghum bicolor)

USDA-ARS?s Scientific Manuscript database

Using suppression subtractive hybridization (SSH) and subsequent microarray analysis, expression profiles of sorghum genes responsive to greenbug phloem-feeding were obtained and identified. Among the profiles, two cDNAs designated to MM73 and MM95 were identified to encode Xa1 (Xa1) and oxysterol ...

Conference on Fire Resistant Materials: A compilation of presentations and papers

NASA Technical Reports Server (NTRS)

Kourtides, D. A. (Editor); Johnson, G. A. (Editor)

1979-01-01

The proceedings of the NASA IRE Resistant Materials Engineering (FIREMEN) Program held at Boeing Commercial Airplane Company, Seattle, Washington, on March 1-2, 1979 are reported. The conference was to discuss the results of research by the National Aeronautics and Space Administration in the field of aircraft fire safety and fire-resistant materials. The program topics include the following: (1) large-scale testing; (2) fire toxicology; (3) polymeric materials; and (4) fire modeling.

Food supply confers calcifiers resistance to ocean acidification.

PubMed

Ramajo, Laura; Pérez-León, Elia; Hendriks, Iris E; Marbà, Núria; Krause-Jensen, Dorte; Sejr, Mikael K; Blicher, Martin E; Lagos, Nelson A; Olsen, Ylva S; Duarte, Carlos M

2016-01-18

Invasion of ocean surface waters by anthropogenic CO2 emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification.

Food supply confers calcifiers resistance to ocean acidification

NASA Astrophysics Data System (ADS)

Ramajo, Laura; Pérez-León, Elia; Hendriks, Iris E.; Marbà, Núria; Krause-Jensen, Dorte; Sejr, Mikael K.; Blicher, Martin E.; Lagos, Nelson A.; Olsen, Ylva S.; Duarte, Carlos M.

2016-01-01

Invasion of ocean surface waters by anthropogenic CO2 emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification.

Food supply confers calcifiers resistance to ocean acidification

PubMed Central

Ramajo, Laura; Pérez-León, Elia; Hendriks, Iris E.; Marbà, Núria; Krause-Jensen, Dorte; Sejr, Mikael K.; Blicher, Martin E.; Lagos, Nelson A.; Olsen, Ylva S.; Duarte, Carlos M.

2016-01-01

Invasion of ocean surface waters by anthropogenic CO2 emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification. PMID:26778520

mTOR Signaling Confers Resistance to Targeted Cancer Drugs.

PubMed

Guri, Yakir; Hall, Michael N

2016-11-01

Cancer is a complex disease and a leading cause of death worldwide. Extensive research over decades has led to the development of therapies that target cancer-specific signaling pathways. However, the clinical benefits of such drugs are at best transient due to tumors displaying intrinsic or adaptive resistance. The underlying compensatory pathways that allow cancer cells to circumvent a drug blockade are poorly understood. We review here recent studies suggesting that mammalian TOR (mTOR) signaling is a major compensatory pathway conferring resistance to many cancer drugs. mTOR-mediated resistance can be cell-autonomous or non-cell-autonomous. These findings suggest that mTOR signaling should be monitored routinely in tumors and that an mTOR inhibitor should be considered as a co-therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

HPV-18 confers resistance to TNF-{alpha} in organotypic cultures of human keratinocytes

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

Boccardo, Enrique; Noya, Francisco; Broker, Thomas R.

2004-10-25

The proinflammatory cytokine tumor necrosis factor-alpha (TNF-{alpha}) inhibits normal keratinocytes proliferation. However, many human papillomavirus (HPV)-immortalized or transformed cell lines are resistant to TNF-{alpha} antiproliferative effect. The present study analyzes the effects of TNF-{alpha} on organotypic cultures of primary human keratinocytes (PHKs) that express HPV-18 oncogenes. Raft cultures prepared with PHKs acutely transfected with HPV-18 whole genome or infected with recombinant retroviruses containing only E6/E7 or E7 were treated with 2 nM TNF-{alpha}. While BrdU incorporation into basal/parabasal cells of normal PHKs cultures was markedly inhibited by TNF-{alpha} cultures transfected with HPV-18 whole genome showed proliferation in all cell strata.more » Furthermore, BrdU incorporation into cultures expressing E6/E7 or E7 was not significantly reduced, indicating that E7 alone confers partial resistance to TNF-{alpha}. Besides, TNF-{alpha} treatment did not alter p16{sup ink4a}, p21{sup cip1}, p27{sup kip1}, or cyclin E levels, but did reduce cyclin A and PCNA levels in sensitive cells.« less

Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation.

PubMed

Bruins Slot, Karsten M H; Berge, Eivind

2013-08-08

Anticoagulant treatment with vitamin K antagonists (VKAs) is aimed at preventing thromboembolic complications and has been the therapy of choice for most people with non-valvular atrial fibrillation (AF) for many decades. A new class of anticoagulants, the factor Xa inhibitors, appear to have several pharmacological and practical advantages over VKAs. To assess the effectiveness and safety of treatment with factor Xa inhibitors versus VKAs for the prevention of cerebral or systemic embolic events in people with AF. We searched the trials registers of the Cochrane Stroke Group and the Cochrane Heart Group (June 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 10), MEDLINE (1950 to April 2013) and EMBASE (1980 to April 2013). In an effort to identify further published, unpublished and ongoing trials we searched trials registers and Google Scholar (July 2012). We also screened reference lists and contacted pharmaceutical companies, authors and sponsors of relevant published trials. Randomised controlled trials that directly compared the effects of long-term treatment (more than four weeks) with factor Xa inhibitors and VKAs for the prevention of cerebral and systemic embolism in patients with AF. We included patients with and without a previous stroke or TIA. The primary efficacy outcome was the composite endpoint of all strokes and other systemic embolic events. Two authors independently assessed trial quality and the risk of bias, and extracted data. We calculated a weighted estimate of the typical treatment effect across trials using the odds ratio (OR) with 95% confidence interval (CI) by means of a fixed-effect model. However, in the case of moderate or high heterogeneity of treatment effects, we used a random-effects model to compare the overall treatment effects and performed a pre-specified sensitivity analysis excluding any fully open-label studies. We included data from 42,084 participants randomised into

Drug resistance. K13-propeller mutations confer artemisinin resistance in Plasmodium falciparum clinical isolates.

PubMed

Straimer, Judith; Gnädig, Nina F; Witkowski, Benoit; Amaratunga, Chanaki; Duru, Valentine; Ramadani, Arba Pramundita; Dacheux, Mélanie; Khim, Nimol; Zhang, Lei; Lam, Stephen; Gregory, Philip D; Urnov, Fyodor D; Mercereau-Puijalon, Odile; Benoit-Vical, Françoise; Fairhurst, Rick M; Ménard, Didier; Fidock, David A

2015-01-23

The emergence of artemisinin resistance in Southeast Asia imperils efforts to reduce the global malaria burden. We genetically modified the Plasmodium falciparum K13 locus using zinc-finger nucleases and measured ring-stage survival rates after drug exposure in vitro; these rates correlate with parasite clearance half-lives in artemisinin-treated patients. With isolates from Cambodia, where resistance first emerged, survival rates decreased from 13 to 49% to 0.3 to 2.4% after the removal of K13 mutations. Conversely, survival rates in wild-type parasites increased from ≤0.6% to 2 to 29% after the insertion of K13 mutations. These mutations conferred elevated resistance to recent Cambodian isolates compared with that of reference lines, suggesting a contemporary contribution of additional genetic factors. Our data provide a conclusive rationale for worldwide K13-propeller sequencing to identify and eliminate artemisinin-resistant parasites. Copyright © 2015, American Association for the Advancement of Science.

Frequency of alleles conferring resistance to a Bacillus thuringiensis toxin in a Philippine population of Scirpophaga incertulas (Lepidoptera: Pyralidae).

PubMed

Bentur, J S; Andow, D A; Cohen, M B; Romena, A M; Gould, F

2000-10-01

Using the F2 screen methodology, we estimated the frequency of alleles conferring resistance to the Cry1Ab toxin of Bacillus thuringiensis Berliner in a Philippine population of the stem borer Scirpophaga incertulas (Walker). Evaluation of >450 isofemale lines for survival of F2 larvae on cry1Ab plants did not detect the presence of an allele conferring a high level of resistance. The frequency of such an allele in the sampled population was conservatively estimated to be <3.6 x 10(-3) with 95% confidence and a detection probability of 94%. However, there was evidence of the presence of alleles conferring partial resistance to Cry1Ab. The frequency of alleles for partial resistance was estimated as 4.8 x 10(-3) with a 95% CI between 1.3 x 10(-3) and 1.04 x 10(-2) and a detection probability of 94%. Our results suggest that the frequency of alleles conferring resistance to Cry1Ab in the population of S. incertulas sampled is not too high to preclude successful implementation of the high dose/refuge resistance management strategy.

A maize caffeoyl-CoA O-methyltransferase gene confers quantitative resistance to multiple pathogens

USDA-ARS?s Scientific Manuscript database

Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement though molecular mechanisms underlying their functions remain largely unknown. A QTL, qMdr9.02, associated with resistance to three important foliar maize diseases, southern leaf blight (SLB), gray leaf spot (GLS)...

Pathotype profile of Xanthomonas oryzae pv. oryzae isolates from North Sumatera

NASA Astrophysics Data System (ADS)

Noer, Z.; Hasanuddin; Lisnawita; Suryanto, D.

2018-02-01

The Bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most important diseases and has caused crop failure in rice crops. This pathogen infects the leaves in all plant growth phases. The purpose of this study is to investigation 10 Xoo isolates pathotype obtained from North Sumatra based on their interactions with 10 near-isogenic rice lines (NIL) of IRRI. The results showed that there are 6 pathotypes of virulence in North Sumatra, they are; pathotype I with incompatible interaction to all Xa genes, pathotype II with compatible interaction to Xa1 and Xa3 genes, while it has incompatible interaction to other genes, pathotype III with compatible interaction to Xa1, Xa5, Xa7, Xa8, Xa10 and Xa11 genes, but it has incompatible interaction to other genes, pathotype IV with compatible interaction to all Xa genes, pathotype V with compatible interaction to Xa1 gene and incompatible interaction to other genes, and pathotype VI with compatible interaction to Xa3 gene and incompatible interaction to other genes. Based on the resistant genes in each individual Xa2, Xa4, and Xa21 genes are the combination of Xa genes which are most suitable for use in the development of rice cultivars in North Sumatra.

Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation.

PubMed

Bruins Slot, Karsten Mh; Berge, Eivind

2018-03-06

Factor Xa inhibitors and vitamin K antagonists (VKAs) are now recommended in treatment guidelines for preventing stroke and systemic embolic events in people with atrial fibrillation (AF). This is an update of a Cochrane review previously published in 2013. To assess the effectiveness and safety of treatment with factor Xa inhibitors versus VKAs for preventing cerebral or systemic embolic events in people with AF. We searched the trials registers of the Cochrane Stroke Group and the Cochrane Heart Group (September 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (August 2017), MEDLINE (1950 to April 2017), and Embase (1980 to April 2017). We also contacted pharmaceutical companies, authors and sponsors of relevant published trials. We used outcome data from marketing authorisation applications of apixaban, edoxaban and rivaroxaban that were submitted to regulatory authorities in Europe and the USA. We included randomised controlled trials (RCTs) that directly compared the effects of long-term treatment (lasting more than four weeks) with factor Xa inhibitors versus VKAs for preventing cerebral and systemic embolism in people with AF. The primary efficacy outcome was the composite endpoint of all strokes and systemic embolic events. Two review authors independently extracted data, and assessed the quality of the trials and the risk of bias. We calculated a weighted estimate of the typical treatment effect across trials using the odds ratio (OR) with 95% confidence interval (CI) by means of a fixed-effect model. In case of moderate or high heterogeneity of treatment effects, we used a random-effects model to compare the overall treatment effects. We also performed a pre-specified sensitivity analysis excluding any open-label studies. We included data from 67,688 participants randomised into 13 RCTs. The included trials directly compared dose-adjusted warfarin with either apixaban, betrixaban, darexaban, edoxaban, idraparinux, idrabiotaparinux, or

Functional assembly of intrinsic coagulation proteases on monocytes and platelets. Comparison between cofactor activities induced by thrombin and factor Xa

PubMed Central

1992-01-01

Generation of coagulation factor Xa by the intrinsic pathway protease complex is essential for normal activation of the coagulation cascade in vivo. Monocytes and platelets provide membrane sites for assembly of components of this protease complex, factors IXa and VIII. Under biologically relevant conditions, expression of functional activity by this complex is associated with activation of factor VIII to VIIIa. In the present studies, autocatalytic regulatory pathways operating on monocyte and platelet membranes were investigated by comparing the cofactor function of thrombin-activated factor VIII to that of factor Xa-activated factor VIII. Reciprocal functional titrations with purified human factor VIII and factor IXa were performed at fixed concentrations of human monocytes, CaCl2, factor X, and either factor IXa or factor VIII. Factor VIII was preactivated with either thrombin or factor Xa, and reactions were initiated by addition of factor X. Rates of factor X activation were measured using chromogenic substrate specific for factor Xa. The K1/2 values, i.e., concentration of factor VIIIa at which rates were half maximal, were 0.96 nM with thrombin- activated factor VIII and 1.1 nM with factor Xa-activated factor VIII. These values are close to factor VIII concentration in plasma. The Vsat, i.e., rates at saturating concentrations of factor VIII, were 33.3 and 13.6 nM factor Xa/min, respectively. The K1/2 and Vsat values obtained in titrations with factor IXa were not significantly different from those obtained with factor VIII. In titrations with factor X, the values of Michaelis-Menten coefficients (Km) were 31.7 nM with thrombin- activated factor VIII, and 14.2 nM with factor Xa-activated factor VIII. Maximal rates were 23.4 and 4.9 nM factor Xa/min, respectively. The apparent catalytic efficiency was similar with either form of factor VIIIa. Kinetic profiles obtained with platelets as a source of membrane were comparable to those obtained with monocytes

Safety of 4-factor prothrombin complex concentrate (4F-PCC) for emergent reversal of factor Xa inhibitors.

PubMed

Tao, Jing; Bukanova, Elena N; Akhtar, Shamsuddin

2018-01-01

Although factor Xa inhibitors have become a popular choice for chronic oral anticoagulation, effective drug reversal remains difficult due to a lack of specific antidote. Currently, 4-factor prothrombin complex concentrate (4F-PCC) is considered the treatment of choice for factor Xa inhibitor-related major bleeding. However, safety of 4F-PCC and its risk of thrombosis when used for this off-label purpose remain unclear. The purpose of this retrospective study is to determine the rate of thromboembolism when 4F-PCC is used for the emergent reversal of factor Xa inhibitors. We conducted a single-center retrospective review of medical records between 2013 and 2017. Patients were included if they received 4F-PCC to reverse rivaroxaban, apixaban, or edoxaban for emergent invasive procedures or during episodes of major bleeding defined as bleeding with hemodynamic instability, fall in hemoglobin of 2 g/dL, or bleeding requiring blood transfusion. Thrombotic events including myocardial infarction, pulmonary embolism, deep vein thrombosis, cerebral vascular accident, and arterial thrombosis of the limb or mesentery were recorded if they occurred within 14 days of 4F-PCC administration. Data was analyzed using point and interval estimation to approximate the rate and confidence interval of thromboembolic events. Forty-three patients were identified in our review. Doses of 4F-PCC were determined by the treating physician and mainly ranged from 25 to 50 IU/kg. Twenty-two patients (51.2%) received both sequential compression devices (SCDs) and subcutaneous heparin for DVT prophylaxis. Twenty-one patients (48.8%) were placed on SCDs only. Three patients received concomitant FFP. Thrombotic events within 14 days of 4F-PCC administration occurred in 1 out of 43 patients (2.1%, 95% CI [0.1-12.3]). This thrombotic event was an upper extremity DVT which occurred 1 day after the patient received 1325 IU (25 IU/kg) of 4F-PCC to reverse rivaroxaban for traumatic intracranial

Conference on Fire Resistant Materials (FIREMEN): A compilation of presentations and papers

NASA Technical Reports Server (NTRS)

Kourtides, D. A. (Editor)

1978-01-01

The proceedings of the NASA Fire Resistant Materials Engineering (FIREMEN) Program held at Ames Research Center on April, 13, 14, 1978 are reported. The purpose of the conference was to discuss the results of NASA in the field of aircraft fire safety and fire resistant materials. The program components include the following: (1) large-scale testing; (2) fire toxicology; (3) polymeric materials; and (4) bibliography related and/or generated from the program.

Multiple origins of resistance-conferring mutations in Plasmodium vivax dihydrofolate reductase

PubMed Central

Hawkins, Vivian N; Auliff, Alyson; Prajapati, Surendra Kumar; Rungsihirunrat, Kanchana; Hapuarachchi, Hapuarachchige C; Maestre, Amanda; O'Neil, Michael T; Cheng, Qin; Joshi, Hema; Na-Bangchang, Kesara; Sibley, Carol Hopkins

2008-01-01

Background In order to maximize the useful therapeutic life of antimalarial drugs, it is crucial to understand the mechanisms by which parasites resistant to antimalarial drugs are selected and spread in natural populations. Recent work has demonstrated that pyrimethamine-resistance conferring mutations in Plasmodium falciparum dihydrofolate reductase (dhfr) have arisen rarely de novo, but spread widely in Asia and Africa. The origin and spread of mutations in Plasmodium vivax dhfr were assessed by constructing haplotypes based on sequencing dhfr and its flanking regions. Methods The P. vivax dhfr coding region, 792 bp upstream and 683 bp downstream were amplified and sequenced from 137 contemporary patient isolates from Colombia, India, Indonesia, Papua New Guinea, Sri Lanka, Thailand, and Vanuatu. A repeat motif located 2.6 kb upstream of dhfr was also sequenced from 75 of 137 patient isolates, and mutational relationships among the haplotypes were visualized using the programme Network. Results Synonymous and non-synonymous single nucleotide polymorphisms (SNPs) within the dhfr coding region were identified, as was the well-documented in-frame insertion/deletion (indel). SNPs were also identified upstream and downstream of dhfr, with an indel and a highly polymorphic repeat region identified upstream of dhfr. The regions flanking dhfr were highly variable. The double mutant (58R/117N) dhfr allele has evolved from several origins, because the 58R is encoded by at least 3 different codons. The triple (58R/61M/117T) and quadruple (57L/61M/117T/173F, 57I/58R/61M/117T and 57L/58R/61M/117T) mutant alleles had at least three independent origins in Thailand, Indonesia, and Papua New Guinea/Vanuatu. Conclusion It was found that the P. vivax dhfr coding region and its flanking intergenic regions are highly polymorphic and that mutations in P. vivax dhfr that confer antifolate resistance have arisen several times in the Asian region. This contrasts sharply with the

Multiple origins of resistance-conferring mutations in Plasmodium vivax dihydrofolate reductase.

PubMed

Hawkins, Vivian N; Auliff, Alyson; Prajapati, Surendra Kumar; Rungsihirunrat, Kanchana; Hapuarachchi, Hapuarachchige C; Maestre, Amanda; O'Neil, Michael T; Cheng, Qin; Joshi, Hema; Na-Bangchang, Kesara; Sibley, Carol Hopkins

2008-04-28

In order to maximize the useful therapeutic life of antimalarial drugs, it is crucial to understand the mechanisms by which parasites resistant to antimalarial drugs are selected and spread in natural populations. Recent work has demonstrated that pyrimethamine-resistance conferring mutations in Plasmodium falciparum dihydrofolate reductase (dhfr) have arisen rarely de novo, but spread widely in Asia and Africa. The origin and spread of mutations in Plasmodium vivax dhfr were assessed by constructing haplotypes based on sequencing dhfr and its flanking regions. The P. vivax dhfr coding region, 792 bp upstream and 683 bp downstream were amplified and sequenced from 137 contemporary patient isolates from Colombia, India, Indonesia, Papua New Guinea, Sri Lanka, Thailand, and Vanuatu. A repeat motif located 2.6 kb upstream of dhfr was also sequenced from 75 of 137 patient isolates, and mutational relationships among the haplotypes were visualized using the programme Network. Synonymous and non-synonymous single nucleotide polymorphisms (SNPs) within the dhfr coding region were identified, as was the well-documented in-frame insertion/deletion (indel). SNPs were also identified upstream and downstream of dhfr, with an indel and a highly polymorphic repeat region identified upstream of dhfr. The regions flanking dhfr were highly variable. The double mutant (58R/117N) dhfr allele has evolved from several origins, because the 58R is encoded by at least 3 different codons. The triple (58R/61M/117T) and quadruple (57L/61M/117T/173F, 57I/58R/61M/117T and 57L/58R/61M/117T) mutant alleles had at least three independent origins in Thailand, Indonesia, and Papua New Guinea/Vanuatu. It was found that the P. vivax dhfr coding region and its flanking intergenic regions are highly polymorphic and that mutations in P. vivax dhfr that confer antifolate resistance have arisen several times in the Asian region. This contrasts sharply with the selective sweep of rare antifolate resistant

Pyramiding transgenes for multiple resistance in rice against bacterial blight, yellow stem borer and sheath blight.

PubMed

Datta, K; Baisakh, N; Thet, K Maung; Tu, J; Datta, S K

2002-12-01

Here we describe the development of transgene-pyramided stable elite rice lines resistant to disease and insect pests by conventional crossing of two transgenic parental lines transformed independently with different genes. The Xa21 gene (resistance to bacterial blight), the Bt fusion gene (for insect resistance) and the chitinase gene (for tolerance of sheath blight) were combined in a single rice line by reciprocal crossing of two transgenic homozygous IR72 lines. F4 plant lines carrying all the genes of interest stably were identified using molecular methods. The identified lines, when exposed to infection caused by Xanthomonas oryzae pv oryzae, showed resistance to bacterial blight. Neonate larval mortality rates of yellow stem borer ( Scirpophaga incertulas) in an insect bioassay of the same identified lines were 100%. The identified line pyramided with different genes to protect against yield loss showed high tolerance of sheath blight disease caused by Rhizoctonia solani.

Deletion of Pten Expands Lung Epithelial Progenitor Pools and Confers Resistance to Airway Injury

PubMed Central

Tiozzo, Caterina; De Langhe, Stijn; Yu, Mingke; Londhe, Vedang A.; Carraro, Gianni; Li, Min; Li, Changgong; Xing, Yiming; Anderson, Stewart; Borok, Zea; Bellusci, Saverio; Minoo, Parviz

2009-01-01

Rationale: Pten is a tumor-suppressor gene involved in stem cell homeostasis and tumorigenesis. In mouse, Pten expression is ubiquitous and begins as early as 7 days of gestation. Pten−/− mouse embryos die early during gestation indicating a critical role for Pten in embryonic development. Objectives: To test the role of Pten in lung development and injury. Methods: We conditionally deleted Pten throughout the lung epithelium by crossing Ptenflox/flox with Nkx2.1-cre driver mice. The resulting PtenNkx2.1-cre mutants were analyzed for lung defects and response to injury. Measurements and Main Results: PtenNkx2.1-cre embryonic lungs showed airway epithelial hyperplasia with no branching abnormalities. In adult mice, PtenNkx2.1-cre lungs exhibit increased progenitor cell pools composed of basal cells in the trachea, CGRP/CC10 double-positive neuroendocrine cells in the bronchi, and CC10/SPC double-positive cells at the bronchioalveolar duct junctions. Pten deletion affected differentiation of various lung epithelial cell lineages, with a decreased number of terminally differentiated cells. Over time, PtenNxk2.1-cre epithelial cells residing in the bronchioalveolar duct junctions underwent proliferation and formed uniform masses, supporting the concept that the cells residing in this distal niche may also be the source of procarcinogenic stem cells. Finally, increased progenitor cells in all the lung compartments conferred an overall selective advantage to naphthalene injury compared with wild-type control mice. Conclusions: Pten has a pivotal role in lung stem cell homeostasis, cell differentiation, and consequently resistance to lung injury. PMID:19574443

Nontraumatic spinal subdural hematoma complicating direct factor Xa inhibitor treatment (rivaroxaban): a challenging management.

PubMed

Dargazanli, Cyril; Lonjon, Nicolas; Gras-Combe, Guillaume

2016-05-01

We report on a 72-year-old male patient who developed a nontraumatic spinal subdural hematoma (SSDH) during rivaroxaban therapy, a relatively new orally administered direct factor Xa inhibitor. The patient sustained a sudden onset of interscapular pain, followed by gait impairment and paraplegia. Magnetic resonance imaging (MRI) of the spine demonstrated SSDH from T6 to T8. Laboratory tests revealed a high rivaroxaban level, associated with a major hemorrhagic risk. Surgery was, therefore, performed the following morning, after normalization of coagulation parameters. Determining the time of safe surgery remains challenging when hemorrhagic complications happen with direct factor Xa inhibitor, especially when neurological prognosis is engaged. Spinal subdural hematoma has not previously been reported following rivaroxaban therapy.

The cytochrome complex SoxXA of Paracoccus pantotrophus is produced in Escherichia coli and functional in the reconstituted sulfur-oxidizing enzyme system.

PubMed

Rother, Dagmar; Friedrich, Cornelius G

2002-07-29

The heterodimeric c-type cytochrome complex SoxXA of Paracoccus pantotrophus was produced in Escherichia coli. The soxX and soxA genes, separated by two genes in the sox gene cluster of P. pantotrophus, were fused with ribosome binding sites optimal for E. coli and combined to give soxXA in pRD133.27. The cytochrome complex SoxXA was produced in E. coli M15 containing pRD133.27, pREP4 encoding the Lac repressor and plasmid pEC86, carrying essential cytochrome c maturation genes. SoxX and SoxA were formed in a ratio of about 2.5:1. SoxA appeared to be unstable when not complexed with SoxX. The cytochrome complex SoxXA, purified to homogeneity from periplasmic extracts of E. coli M15 (pRD133.27, pREP4, pEC86), exhibited identical biochemical and biophysical properties as compared to SoxXA of P. pantotrophus. Moreover, this cytochrome complex was shown to be equally catalytically active with respect to rates and reactivity with different sulfur substrates in the reconstituted sulfur-oxidizing enzyme system using homogeneous Sox-proteins of P. pantotrophus. Homogeneous SoxX was catalytically inactive.

Future therapeutic directions for factor Xa inhibition in the prophylaxis and treatment of thrombotic disorders.

PubMed

Turpie, Alexander G G

2003-11-15

The targeted mechanism of factor Xa inhibition has been studied extensively, initially as prophylaxis for venous thromboembolism (VTE) in the orthopedic surgical setting. Future therapeutic directions for selective factor Xa inhibition in the management of other thrombotic diseases are discussed. Thromboembolic diseases can occur in the venous or arterial sides of the circulatory system. Factor Xa inhibition is a targeted approach to anticoagulation that resulted from significant advances in our understanding of the coagulation cascade. The factor Xa inhibitor fondaparinux has been studied extensively in the orthopedic surgical setting for the prophylaxis of VTE. Current investigations that are under way or completed evaluate the efficacy and safety of fondaparinux for the management of various thrombotic diseases. The future development of fondaparinux resides primarily in three therapeutic areas: prevention of VTE, treatment of VTE, and treatment of acute coronary syndromes. For the prevention of VTE, fondaparinux has been studied as extended prophylaxis following hip fracture surgery (PENTHIFRA Plus), for use in high-risk abdominal surgical patients (PEGASUS and APOLLO), and for use in medical patients (ARTEMIS). Studies evaluating fondaparinux for the treatment of VTE are part of the large MATISSE clinical program (MATISSE DVT and MATISSE PE). Fondaparinux was investigated in phase 2 studies for the treatment of acute coronary syndromes, including acute ST-segment myocardial infarction (PENTALYSE) and unstable angina (PENTUA). Encouraging data from these trials are the basis for phase 3 programs in this area (MICHELANGELO). The orthopedic prophylactic and nonorthopedic clinical programs for fondaparinux in the management of thrombosis support the concept that targeted inhibition of coagulation is an effective advance in antithrombotic therapy.

Interfamily Transfer of Dual NB-LRR Genes Confers Resistance to Multiple Pathogens

PubMed Central

Narusaka, Mari; Kubo, Yasuyuki; Hatakeyama, Katsunori; Imamura, Jun; Ezura, Hiroshi; Nanasato, Yoshihiko; Tabei, Yutaka; Takano, Yoshitaka; Shirasu, Ken; Narusaka, Yoshihiro

2013-01-01

A major class of disease resistance (R) genes which encode nucleotide binding and leucine rich repeat (NB-LRR) proteins have been used in traditional breeding programs for crop protection. However, it has been difficult to functionally transfer NB-LRR-type R genes in taxonomically distinct families. Here we demonstrate that a pair of Arabidopsis (Brassicaceae) NB-LRR-type R genes, RPS4 and RRS1, properly function in two other Brassicaceae, Brassica rapa and Brassica napus, but also in two Solanaceae, Nicotiana benthamiana and tomato (Solanum lycopersicum). The solanaceous plants transformed with RPS4/RRS1 confer bacterial effector-specific immunity responses. Furthermore, RPS4 and RRS1, which confer resistance to a fungal pathogen Colletotrichum higginsianum in Brassicaceae, also protect against Colletotrichum orbiculare in cucumber (Cucurbitaceae). Importantly, RPS4/RRS1 transgenic plants show no autoimmune phenotypes, indicating that the NB-LRR proteins are tightly regulated. The successful transfer of two R genes at the family level implies that the downstream components of R genes are highly conserved. The functional interfamily transfer of R genes can be a powerful strategy for providing resistance to a broad range of pathogens. PMID:23437080

PAK4 confers the malignance of cervical cancers and contributes to the cisplatin-resistance in cervical cancer cells via PI3K/AKT pathway.

PubMed

Shu, Xiang-Rong; Wu, Jing; Sun, He; Chi, Li-Qun; Wang, Jin-Huan

2015-09-28

Multiple protein or microRNA markers have been recognized to contribute to the progression and recurrence of cervical cancers. Particular those, which are associated with the chemo- or radio-resistance of cervical cancers, have been proposed to be promising and to facilitate the definition for cervical cancer treatment options. This study was designed to explore the potential prognosis value of p21-activated kinase (PAK)-4 in cervical cancer, via the Kaplan-Meier analysis, log-rank test and Cox regression analysis, and then to investigate the regulatory role of PAK4 in the cisplatin resistance in cervical cancer cells, via the strategies of both PAK4 overexpression and PAK4 knockout. It was demonstrated that PAK4 was upregulated in cervical cancer tissues, in an association with the cancer's malignance variables such as FIGO stage, lymph node or distant metastasis and the poor histological grade. The high PAK4 expression was also independently associated with poor prognosis to cervical cancer patients. Moreover, PAK4 confers cisplatin resistance in cervical cancer Hela or Caski cells. In addition, the PI3K/Akt pathway has been implicated in the PAK4-confered cisplatin resistance. And the PI3K/Akt inhibitor, LY294002, markedly deteriorated the cisplatin-mediated viability reduction of Hela or Caski cells, indicating the involvement of PI3K/Akt pathway in the cisplatin resistance in cervical cancer cells. This study has confirmed the significant prognostic role of PAK4 level in cervical cancer patients and has recognized the regulatory role in cervical cancer progression. Moreover, our study has indicated that PAK4 also confers the chemoresistance of cervical cancer cells in a PI3K/Akt-dependent way. Thus, our study indicates PAK4 as a promising marker for cervical cancer treatment.

Voltage-sensitive sodium channel mutations S989P + V1016G in Aedes aegypti confer variable resistance to pyrethroids, DDT and oxadiazines.

PubMed

Smith, Letícia B; Kasai, Shinji; Scott, Jeffrey G

2018-03-01

Aedes aegypti is a vector of several important human pathogens. Control efforts rely primarily on pyrethroid insecticides for adult mosquito control, especially during disease outbreaks. A. aegypti has developed resistance nearly everywhere it occurs and insecticides are used. An important mechanism of resistance is due to mutations in the voltage-sensitive sodium channel (Vssc) gene. Two mutations, in particular, S989P + V1016G, commonly occur together in parts of Asia. We have created a strain (KDR:ROCK) that contains the Vssc mutations S989P + V1016G as the only mechanism of pyrethroid resistance within the genetic background of Rockefeller (ROCK), a susceptible lab strain. We created KDR:ROCK by crossing the pyrethroid-resistant strain Singapore with ROCK followed by four backcrosses with ROCK and Vssc S989P + V1016G genotype selections. We determined the levels of resistance conferred to 17 structurally diverse pyrethroids, the organochloride DDT, and oxadiazines (VSSC blockers) indoxacarb (proinsecticide) and DCJW (the active metabolite of indoxacarb). Levels of resistance to the pyrethroids were variable, ranging from 21- to 107-fold, but no clear pattern between resistance and chemical structure was observed. Resistance is inherited as an incompletely recessive trait. KDR:ROCK had a > 2000-fold resistance to DDT, 37.5-fold cross-resistance to indoxacarb and 13.4-fold cross-resistance to DCJW. Etofenprox (and DDT) should be avoided in areas where Vssc mutations S989P + V1016G exist at high frequencies. We found that pyrethroid structure cannot be used to predict the level of resistance conferred by kdr. These results provide useful information for resistance management and for better understanding pyrethroid interactions with VSSC. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of

A gene encoding maize caffeoyl-CoA O-methyltransferase confers quantitative resistance to multiple pathogens.

PubMed

Yang, Qin; He, Yijian; Kabahuma, Mercy; Chaya, Timothy; Kelly, Amy; Borrego, Eli; Bian, Yang; El Kasmi, Farid; Yang, Li; Teixeira, Paulo; Kolkman, Judith; Nelson, Rebecca; Kolomiets, Michael; L Dangl, Jeffery; Wisser, Randall; Caplan, Jeffrey; Li, Xu; Lauter, Nick; Balint-Kurti, Peter

2017-09-01

Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement, although the molecular mechanisms underlying their functions remain largely unknown. A quantitative trait locus, qMdr 9.02 , associated with resistance to three important foliar maize diseases-southern leaf blight, gray leaf spot and northern leaf blight-has been identified on maize chromosome 9. Through fine-mapping, association analysis, expression analysis, insertional mutagenesis and transgenic validation, we demonstrate that ZmCCoAOMT2, which encodes a caffeoyl-CoA O-methyltransferase associated with the phenylpropanoid pathway and lignin production, is the gene within qMdr 9.02 conferring quantitative resistance to both southern leaf blight and gray leaf spot. We suggest that resistance might be caused by allelic variation at the level of both gene expression and amino acid sequence, thus resulting in differences in levels of lignin and other metabolites of the phenylpropanoid pathway and regulation of programmed cell death.

Potent arterial antithrombotic effect of direct factor-Xa inhibition with ZK-807834 administered to coronary artery disease patients.

PubMed

Zafar, M Urooj; Farkouh, Michael E; Osende, Julio; Shimbo, Daichi; Palencia, Stella; Crook, Julia; Leadley, Robert; Fuster, Valentin; Chesebro, James H

2007-03-01

It was the objective of this study to evaluate the anti-thrombotic potency of direct factor-Xa inhibition with ZK-807834 in stable coronary patients, using an ex-vivo model of arterial thrombus formation. Tissue factor pathway is important in atherothrombosis. Direct factor-Xa blockade may more potently reduce thrombosis and prevent coronary events. Badimon Perfusion Chamber 5-minute quantitative studies have shown 40-55% arterial thrombus reduction with abciximab, 23% with clopidogrel, but none with heparin. Coronary patients (n = 18, 59 +/- 9 years, 55% males) were blindly randomized to four groups receiving 24-hour infusion of a low, medium or high dose of direct factor- Xa inhibitor ZK-807834, or placebo. Arterial thrombus formation was measured in Badimon Chamber at baseline, end-of-infusion [EoI], and four hours and eight hours after EoI, and factor-X activity, prothrombin time [PT] ratio and plasma drug levels were measured simultaneously. For the low-, medium- and high-dose ZK-807834 groups, mean percent-reduction in thrombus size from baseline to EoI were 29%, 34% and 68%, respectively (p < 0.001), and at 8-h post EoI were 11%, 19% and 27%, respectively (p < 0.01). Mean PT-ratio prolongation showed a strong linear relationship (Pearson's r = 0.93) with ZK-807834 plasma concentration. Mean percent-reduction in factor-X activity from baseline was 13%, 42% and 58%, respectively. Placebo had no effect on thrombus size or factor-X activity. In conclusion, direct factor-Xa inhibition with ZK-807834 markedly reduces ex-vivo arterial thrombus formation and factor-X activity in a dose-dependent manner. Plasma levels of ZK-807834 show a strong linear correlation with PT ratio. This direct factor-Xa inhibitor may reduce the need for additional potent glycoprotein IIbIIIa inhibition.

Recombineering reveals a diverse collection of ribosomal proteins L4 and L22 that confer resistance to macrolide antibiotics

PubMed Central

Diner, Elie J.; Hayes, Christopher S.

2009-01-01

Summary Mutations in ribosomal proteins L4 and L22 confer resistance to erythromycin and other macrolide antibiotics in a variety of bacteria. L4 and L22 have elongated loops whose tips converge in the peptide exit tunnel near the macrolide binding site, and resistance mutations typically affect residues within these loops. Here, we use bacteriophage λ Red-mediated recombination, or “recombineering”, to uncover new L4 and L22 alleles that confer macrolide resistance in Escherichia coli. We randomized residues at the tips of the L4 and L22 loops using recombineered oligonucleotide libraries, and selected the mutagenized cells for erythromycin-resistant mutants. These experiments led to the identification of 341 different resistance mutations encoding 278 unique L4 and L22 proteins – the overwhelming majority of which are novel. Many resistance mutations were complex, involving multiple missense mutations, in-frame deletions, and insertions. Transfer of L4 and L22 mutations into wild-type cells by phage P1-mediated transduction demonstrated that each allele was sufficient to confer macrolide resistance. Although L4 and L22 mutants are typically resistant to most macrolides, selections carried out on different antibiotics revealed macrolide-specific resistance mutations. L22 Lys90Trp is one such allele, which confers resistance to erythromycin, but not tylosin or spiramycin. Purified L22 Lys90Trp ribosomes show reduced erythromycin binding, but have the same affinity for tylosin as wild-type ribosomes. Moreover, DMS methylation protection assays demonstrated that L22 Lys90Trp ribosomes bind tylosin more readily than erythromycin in vivo. This work underscores the exceptional functional plasticity of the L4 and L22 proteins, and highlights the utility of Red-mediated recombination in targeted genetic selections. PMID:19150357

Thymidine Kinase 1 Loss Confers Trifluridine Resistance without Affecting 5-Fluorouracil Metabolism and Cytotoxicity.

PubMed

Edahiro, Keitaro; Iimori, Makoto; Kobunai, Takashi; Morikawa-Ichinose, Tomomi; Miura, Daisuke; Kataoka, Yuki; Niimi, Shinichiro; Wakasa, Takeshi; Saeki, Hiroshi; Oki, Eiji; Kitao, Hiroyuki; Maehara, Yoshihiko

2018-06-04

Acquired resistance to therapeutic drugs is a serious problem for cancer patients receiving systemic treatment. Experimentally, drug resistance is established in cell lines in vitro by repeated, continuous exposure to escalating concentrations of the drug; however, the precise mechanism underlying the acquired resistance is not always known. Here, it is demonstrated that the human colorectal cancer cell line DLD1 with acquired resistance to trifluridine (FTD), a key component of the novel, orally administered nucleoside analog-type chemotherapeutic drug trifluridine/tipiracil, lacks functional thymidine kinase 1 (TK1) expression because of one nonsense mutation in the coding exon. Targeted disruption of the TK1 gene also conferred severe FTD resistance, indicating that the loss of TK1 protein expression is the primary cause of FTD resistance. Both FTD-resistant DLD1 cells and DLD1-TK1-/- cells exhibited similar 5-fluorouracil (5-FU) sensitivity to that of the parental DLD1 line. The quantity of cellular pyrimidine nucleotides in these cells and the kinetics of thymidylate synthase ternary complex formation in 5-FU-treated cells is similar to DLD1 cells, indicating that 5-FU metabolism and cytotoxicity were unaffected. The present data provide molecular-based evidence that acquired resistance to FTD does not confer 5-FU resistance, implying that 5-FU-based chemotherapy would be effective even in tumors that become refractory to FTD during trifluridine/tipiracil treatment. 5-fluorouracil-based chemotherapy would be effective even in tumors that become refractory to trifluridine during combined trifluridine/tipiracil treatment. Copyright ©2018, American Association for Cancer Research.

Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniae

PubMed Central

Bossé, Janine T.; Li, Yanwen; Walker, Stephanie; Atherton, Tom; Fernandez Crespo, Roberto; Williamson, Susanna M.; Rogers, Jon; Chaudhuri, Roy R.; Weinert, Lucy A.; Oshota, Olusegun; Holden, Matt T. G.; Maskell, Duncan J.; Tucker, Alexander W.; Wren, Brendan W.; Rycroft, Andrew N.; Langford, Paul R.

2015-01-01

Objectives The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in England. Methods Clinical isolates collected between 1998 and 2011 were tested for resistance to trimethoprim and sulphonamide. The genetic basis of trimethoprim resistance was determined by shotgun WGS analysis and the subsequent isolation and sequencing of plasmids. Results A total of 16 (out of 106) A. pleuropneumoniae isolates were resistant to both trimethoprim (MIC >32 mg/L) and sulfisoxazole (MIC ≥256 mg/L), and a further 32 were resistant only to sulfisoxazole (MIC ≥256 mg/L). Genome sequence data for the trimethoprim-resistant isolates revealed the presence of the dfrA14 dihydrofolate reductase gene. The distribution of plasmid sequences in multiple contigs suggested the presence of two distinct dfrA14-containing plasmids in different isolates, which was confirmed by plasmid isolation and sequencing. Both plasmids encoded mobilization genes, the sulphonamide resistance gene sul2, as well as dfrA14 inserted into strA, a streptomycin-resistance-associated gene, although the gene order differed between the two plasmids. One of the plasmids further encoded the strB streptomycin-resistance-associated gene. Conclusions This is the first description of mobilizable plasmids conferring trimethoprim resistance in A. pleuropneumoniae and, to our knowledge, the first report of dfrA14 in any member of the Pasteurellaceae. The identification of dfrA14 conferring trimethoprim resistance in A. pleuropneumoniae isolates will facilitate PCR screens for resistance to this important antimicrobial. PMID:25957382

Towards Positional Isolation of Three Quantitative Trait Loci Conferring Resistance to Powdery Mildew in Two Spanish Barley Landraces

PubMed Central

Silvar, Cristina; Perovic, Dragan; Nussbaumer, Thomas; Spannagl, Manuel; Usadel, Björn; Casas, Ana; Igartua, Ernesto; Ordon, Frank

2013-01-01

Three quantitative trait loci (QTL) conferring broad spectrum resistance to powdery mildew, caused by the fungus Blumeria graminis f. sp. hordei, were previously identified on chromosomes 7HS, 7HL and 6HL in the Spanish barley landrace-derived lines SBCC097 and SBCC145. In the present work, a genome-wide putative linear gene index of barley (Genome Zipper) and the first draft of the physical, genetic and functional sequence of the barley genome were used to go one step further in the shortening and explicit demarcation on the barley genome of these regions conferring resistance to powdery mildew as well as in the identification of candidate genes. First, a comparative analysis of the target regions to the barley Genome Zippers of chromosomes 7H and 6H allowed the development of 25 new gene-based molecular markers, which slightly better delimit the QTL intervals. These new markers provided the framework for anchoring of genetic and physical maps, figuring out the outline of the barley genome at the target regions in SBCC097 and SBCC145. The outermost flanking markers of QTLs on 7HS, 7HL and 6HL defined a physical area of 4 Mb, 3.7 Mb and 3.2 Mb, respectively. In total, 21, 10 and 16 genes on 7HS, 7HL and 6HL, respectively, could be interpreted as potential candidates to explain the resistance to powdery mildew, as they encode proteins of related functions with respect to the known pathogen defense-related processes. The majority of these were annotated as belonging to the NBS-LRR class or protein kinase family. PMID:23826271

Nineteenth Space Simulation Conference Cost Effective Testing for the 21st Century

NASA Technical Reports Server (NTRS)

Stecher, Joseph L., III (Compiler)

1997-01-01

The Nineteenth Space Simulation Conference was hosted by the Institute of Environmental Sciences (IES) and was supported by the American Institute of Aeronautics and Astronautics (AIAA), the American Society for Testing and Materials (ASTM), the National Aeronautics and Space Administration (NASA), and the Canadian Space Agency (CSA). These proceedings attest to the scope of the conference; papers were presented on topics as diverse as shuttle payload contamination effects, simulating Martian environment for testing, to state-of-the-art 6-axis hydraulic shaker testing system. A good cross section of the international aerospace community took advantage of the opportunity to get together, to share their experiences, and to participate in the technical sessions. The two invited keynote speakers were Lieutenant General Malcolm O'Neill (USA, Ret.), past Director of BMDO, and Mr. Thomas Coughlin, Space Programs Manager at the Johns Hopkins University Applied Physics Laboratory. Their most informative and thought provoking talks were on cost effective testing approaches in Defense Department programs for the 21st Century and what part testing plays in the faster, better, cheaper approach for the NEAR and APL programs, respectively. The preceding tutorial and the tour of the Garber Facility of the Air and Space Museum rounded out a comprehensive conference contributing to the knowledge base vital to cost effective testing for successful missions into the 21st Century.

The 2NS Translocation from Aegilops ventricosa Confers Resistance to the Triticum Pathotype of Magnaporthe oryzae

PubMed Central

Cruz, C.D.; Peterson, G.L.; Bockus, W.W.; Kankanala, P.; Dubcovsky, J.; Jordan, K.W.; Akhunov, E.; Chumley, F.; Baldelomar, F.D.; Valent, B.

2016-01-01

Wheat blast is a serious disease caused by the fungus Magnaporthe oryzae (Triticum pathotype) (MoT). The objective of this study was to determine the effect of the 2NS translocation from Aegilops ventricosa (Zhuk.) Chennav on wheat head and leaf blast resistance. Disease phenotyping experiments were conducted in growth chamber, greenhouse, and field environments. Among 418 cultivars of wheat (Triticum aestivum L.), those with 2NS had 50.4 to 72.3% less head blast than those without 2NS when inoculated with an older MoT isolate under growth chamber conditions. When inoculated with recently collected isolates, cultivars with 2NS had 64.0 to 80.5% less head blast. Under greenhouse conditions when lines were inoculated with an older MoT isolate, those with 2NS had a significant head blast reduction. With newer isolates, not all lines with 2NS showed a significant reduction in head blast, suggesting that the genetic background and/or environment may influence the expression of any resistance conferred by 2NS. However, when near-isogenic lines (NILs) with and without 2NS were planted in the field, there was strong evidence that 2NS conferred resistance to head blast. Results from foliar inoculations suggest that the resistance to head infection that is imparted by the 2NS translocation does not confer resistance to foliar disease. In conclusion, the 2NS translocation was associated with significant reductions in head blast in both spring and winter wheat. PMID:27814405

Novel α-Tubulin Mutations Conferring Resistance to Dinitroaniline Herbicides in Lolium rigidum

PubMed Central

Chu, Zhizhan; Chen, Jinyi; Nyporko, Alex; Han, Heping; Yu, Qin; Powles, Stephen

2018-01-01

The dinitroaniline herbicides (particularly trifluralin) have been globally used in many crops for selective grass weed control. Consequently, trifluralin resistance has been documented in several important crop weed species and has recently reached a level of concern in Australian Lolium rigidum populations. Here, we report novel mutations in the L. rigidum α-tubulin gene which confer resistance to trifluralin and other dinitroaniline herbicides. Nucleotide mutations at the highly conserved codon Arg-243 resulted in amino acid substitutions of Met or Lys. Rice calli transformed with the mutant 243-Met or 243-Lys α-tubulin genes were 4- to 8-fold more resistant to trifluralin and other dinitroaniline herbicides (e.g., ethalfluralin and pendimethalin) compared to calli transformed with the wild type α-tubulin gene from L. rigidum. Comprehensive modeling of molecular docking predicts that Arg-243 is close to the trifluralin binding site on the α-tubulin surface and that replacement of Arg-243 by Met/Lys-243 results in a spatial shift of the trifluralin binding domain, reduction of trifluralin-tubulin contacts, and unfavorable interactions. The major effect of these substitutions is a significant rise of free interaction energy between α-tubulin and trifluralin, as well as between trifluralin and its whole molecular environment. These results demonstrate that the Arg-243 residue in α-tubulin is a determinant for trifluralin sensitivity, and the novel Arg-243-Met/Lys mutations may confer trifluralin resistance in L. rigidum. PMID:29472938

MENA confers resistance to paclitaxel in triple-negative breast cancer

PubMed Central

Oudin, Madeleine J.; Barbier, Lucie; Schäfer, Claudia; Kosciuk, Tatsiana; Miller, Miles A.; Han, Sangyoon; Jonas, Oliver; Lauffenburger, Douglas A.; Gertler, Frank B.

2017-01-01

Taxane therapy remains the standard of care for triple-negative breast cancer. However, high frequencies of recurrence and progression in treated patients indicate that metastatic breast cancer cells can acquire resistance to this drug. The actin regulatory protein MENA, particularly its invasive isoform, MENAINV, are established drivers of metastasis. MENAINV expression is significantly correlated with metastasis and poor outcome in human breast cancer patients. We investigated whether MENA isoforms might play a role in driving resistance to chemotherapeutics. We find that both MENA and MENAINV confer resistance to the taxane paclitaxel, but not to the widely used DNA damaging agents doxorubicin or cisplatin. Furthermore, paclitaxel treatment does not attenuate growth of MENAINV-driven metastatic lesions. Mechanistically, MENA isoform expression alters the ratio of dynamic and stable microtubule populations in paclitaxel-treated cells. MENA expression also increases MAPK signaling in response to paclitaxel treatment. Decreasing ERK phosphorylation by co-treatment with MEK inhibitor restored paclitaxel sensitivity by driving microtubule stabilization in MENA isoform-expressing cells. Our results reveal a novel mechanism of taxane resistance in highly metastatic breast cancer cells and identify a combination therapy to overcome such resistance. PMID:27811011

National parks : transportation alternatives and advanced technology for the 21st century : conference proceedings

DOT National Transportation Integrated Search

1999-06-03

This overview provides a description of the proceedings of a conference entitled, "National Parks: Transportation Alternatives and Advanced Technology for the 21st Century," sponsored by the Western Transportation Institute at Montana State Universit...

Clinical impact of major bleeding in patients with venous thromboembolism treated with factor Xa inhibitors or vitamin K antagonists. An individual patient data meta-analysis.

PubMed

Bleker, Suzanne M; Brekelmans, Marjolein P A; Eerenberg, Elise S; Cohen, Alexander T; Middeldorp, Saskia; Raskob, Gary; Büller, Harry R

2017-10-05

Factor Xa (fXa)-inhibitors are as effective and safer than vitamin-K-antagonists (VKA) in the treatment of venous thromboembolism (VTE). We previously classified the severity of clinical presentation and course of all major bleeding events from the EINSTEIN, AMPLIFY and HOKUSAI-VTE trials separately. The current aim was to combine these findings in order to increase precision, assess a class effect and analyse presentation and course for different types of bleeding, i. e. intracranial, gastro-intestinal, and other. We classified the clinical presentation and course of all major bleeding events using pre-defined criteria. Both classifications comprised four categories; one being the mildest, and four the most severe. Odds ratios (OR) were calculated for all events classified as category three or four between fXa-inhibitors and VKA recipients. Also, ORs were computed for different types of bleeding. Major bleeding occurred in 111 fXa-inhibitor recipients and in 187 LMWH/VKA recipients. The clinical presentation was classified as category three or four in 35 % and 48 % of the major bleeds in fXa inhibitor and VKA recipients, respectively (OR 0.59, 95 % CI 0.36-0.97). For intracranial, gastro-intestinal and other bleeding a trend towards a less severe presentation was observed for patients treated with fXa inhibitors. Clinical course was classified as severe in 22 % of the fXa inhibitor and 25 % of the VKA associated bleeds (OR 0.83, 95 % CI 0.47-1.46). In conclusion, FXa inhibitor associated major bleeding events had a significantly less severe presentation and a similar course compared to VKA. This finding was consistent for different types of bleeding.

Mutations in the Plasmodium falciparum Cyclic Amine Resistance Locus (PfCARL) Confer Multidrug Resistance.

PubMed

LaMonte, Gregory; Lim, Michelle Yi-Xiu; Wree, Melanie; Reimer, Christin; Nachon, Marie; Corey, Victoria; Gedeck, Peter; Plouffe, David; Du, Alan; Figueroa, Nelissa; Yeung, Bryan; Bifani, Pablo; Winzeler, Elizabeth A

2016-07-05

Mutations in the Plasmodium falciparum cyclic amine resistance locus (PfCARL) are associated with parasite resistance to the imidazolopiperazines, a potent class of novel antimalarial compounds that display both prophylactic and transmission-blocking activity, in addition to activity against blood-stage parasites. Here, we show that pfcarl encodes a protein, with a predicted molecular weight of 153 kDa, that localizes to the cis-Golgi apparatus of the parasite in both asexual and sexual blood stages. Utilizing clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene introduction of 5 variants (L830V, S1076N/I, V1103L, and I1139K), we demonstrate that mutations in pfcarl are sufficient to generate resistance against the imidazolopiperazines in both asexual and sexual blood-stage parasites. We further determined that the mutant PfCARL protein confers resistance to several structurally unrelated compounds. These data suggest that PfCARL modulates the levels of small-molecule inhibitors that affect Golgi-related processes, such as protein sorting or membrane trafficking, and is therefore an important mechanism of resistance in malaria parasites. Several previous in vitro evolution studies have implicated the Plasmodium falciparum cyclic amine resistance locus (PfCARL) as a potential target of imidazolopiperazines, potent antimalarial compounds with broad activity against different parasite life cycle stages. Given that the imidazolopiperazines are currently being tested in clinical trials, understanding their mechanism of resistance and the cellular processes involved will allow more effective clinical usage. Copyright © 2016 LaMonte et al.

Molecular survey of turfgrass species for mutations conferring resistance to ACCase inhibiting herbicides

USDA-ARS?s Scientific Manuscript database

The control of grassy weeds in turfgrass is often problematic due to lack of herbicide selectivity. Seven different naturally occurring mutation sites have been reported to confer resistance to Acetyl coenzyme A carboxylase inhibiting herbicides. One or more of these mutation sites may hold potentia...

Unfractionated heparin activity measured by anti-factor Xa levels is associated with the need for extracorporeal membrane oxygenation circuit/membrane oxygenator change: a retrospective pediatric study.

PubMed

Irby, Katherine; Swearingen, Christopher; Byrnes, Jonathan; Bryant, Joshua; Prodhan, Parthak; Fiser, Richard

2014-05-01

Investigate whether anti-Factor Xa levels are associated with the need for change of circuit/membrane oxygenator secondary to thrombus formation in pediatric patients. Retrospective single institution study. Retrospective record review of 62 pediatric patients supported with extracorporeal membrane oxygenation from 2009 to 2011. Data on standard demographic characteristics, indications for extracorporeal membrane oxygenation, duration of extracorporeal membrane oxygenation, activated clotting time measurements, anti-Factor Xa measurements, and heparin infusion rate were collected. Generalized linear models were used to associate anti-Factor Xa concentrations and need for change of either entire circuit/membrane oxygenator secondary to thrombus formation. Sixty-two patients met study inclusion criteria. No-circuit change was required in 45 of 62 patients. Of 62 patients, 17 required change of circuit/membrane oxygenator due to thrombus formation. Multivariate analysis of daily anti-Factor Xa measurements throughout duration of extracorporeal membrane oxygenation support estimated a mean anti-Factor Xa concentration of 0.20 IU/mL (95% CI, 0.16, 0.24) in no-complete-circuit group that was significantly higher than the estimated concentration of 0.13 IU/mL (95% CI, 0.12, 0.14) in complete-circuit group (p = 0.001). A 0.01 IU/mL decrease in anti-Factor Xa increased odds of need for circuit/membrane oxygenator change by 5% (odds ratio = 1.105; 95% CI, 1.00, 1.10; p = 0.044). Based on the observed anti-Factor Xa concentrations, complete-circuit group had 41% increased odds for requiring circuit/membrane oxygenator change compared with no-complete-circuit group (odds ratio = 1.41; 95% CI, 1.01, 1.96; p = 0.044). Mean daily activated clotting time measurement (p = 0.192) was not different between groups, but mean daily heparin infusion rate (p < 0.001) was significantly different between the two groups. Higher anti-Factor Xa concentrations were associated with freedom from

Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniae.

PubMed

Bossé, Janine T; Li, Yanwen; Walker, Stephanie; Atherton, Tom; Fernandez Crespo, Roberto; Williamson, Susanna M; Rogers, Jon; Chaudhuri, Roy R; Weinert, Lucy A; Oshota, Olusegun; Holden, Matt T G; Maskell, Duncan J; Tucker, Alexander W; Wren, Brendan W; Rycroft, Andrew N; Langford, Paul R

2015-08-01

The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in England. Clinical isolates collected between 1998 and 2011 were tested for resistance to trimethoprim and sulphonamide. The genetic basis of trimethoprim resistance was determined by shotgun WGS analysis and the subsequent isolation and sequencing of plasmids. A total of 16 (out of 106) A. pleuropneumoniae isolates were resistant to both trimethoprim (MIC >32 mg/L) and sulfisoxazole (MIC ≥256 mg/L), and a further 32 were resistant only to sulfisoxazole (MIC ≥256 mg/L). Genome sequence data for the trimethoprim-resistant isolates revealed the presence of the dfrA14 dihydrofolate reductase gene. The distribution of plasmid sequences in multiple contigs suggested the presence of two distinct dfrA14-containing plasmids in different isolates, which was confirmed by plasmid isolation and sequencing. Both plasmids encoded mobilization genes, the sulphonamide resistance gene sul2, as well as dfrA14 inserted into strA, a streptomycin-resistance-associated gene, although the gene order differed between the two plasmids. One of the plasmids further encoded the strB streptomycin-resistance-associated gene. This is the first description of mobilizable plasmids conferring trimethoprim resistance in A. pleuropneumoniae and, to our knowledge, the first report of dfrA14 in any member of the Pasteurellaceae. The identification of dfrA14 conferring trimethoprim resistance in A. pleuropneumoniae isolates will facilitate PCR screens for resistance to this important antimicrobial. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

Metabolic and Target-Site Mechanisms Combine to Confer Strong DDT Resistance in Anopheles gambiae

PubMed Central

Mitchell, Sara N.; Rigden, Daniel J.; Dowd, Andrew J.; Lu, Fang; Wilding, Craig S.; Weetman, David; Dadzie, Samuel; Jenkins, Adam M.; Regna, Kimberly; Boko, Pelagie; Djogbenou, Luc; Muskavitch, Marc A. T.; Ranson, Hilary; Paine, Mark J. I.; Mayans, Olga; Donnelly, Martin J.

2014-01-01

The development of resistance to insecticides has become a classic exemplar of evolution occurring within human time scales. In this study we demonstrate how resistance to DDT in the major African malaria vector Anopheles gambiae is a result of both target-site resistance mechanisms that have introgressed between incipient species (the M- and S-molecular forms) and allelic variants in a DDT-detoxifying enzyme. Sequencing of the detoxification enzyme, Gste2, from DDT resistant and susceptible strains of An. gambiae, revealed a non-synonymous polymorphism (I114T), proximal to the DDT binding domain, which segregated with strain phenotype. Recombinant protein expression and DDT metabolism analysis revealed that the proteins from the susceptible strain lost activity at higher DDT concentrations, characteristic of substrate inhibition. The effect of I114T on GSTE2 protein structure was explored through X-ray crystallography. The amino acid exchange in the DDT-resistant strain introduced a hydroxyl group nearby the hydrophobic DDT-binding region. The exchange does not result in structural alterations but is predicted to facilitate local dynamics and enzyme activity. Expression of both wild-type and 114T alleles the allele in Drosophila conferred an increase in DDT tolerance. The 114T mutation was significantly associated with DDT resistance in wild caught M-form populations and acts in concert with target-site mutations in the voltage gated sodium channel (Vgsc-1575Y and Vgsc-1014F) to confer extreme levels of DDT resistance in wild caught An. gambiae. PMID:24675797

Bactobolin resistance is conferred by mutations in the L2 ribosomal protein.

PubMed

Chandler, Josephine R; Truong, Thao T; Silva, Patricia M; Seyedsayamdost, Mohammad R; Carr, Gavin; Radey, Matthew; Jacobs, Michael A; Sims, Elizabeth H; Clardy, Jon; Greenberg, E Peter

2012-12-18

Burkholderia thailandensis produces a family of polyketide-peptide molecules called bactobolins, some of which are potent antibiotics. We found that growth of B. thailandensis at 30°C versus that at 37°C resulted in increased production of bactobolins. We purified the three most abundant bactobolins and determined their activities against a battery of bacteria and mouse fibroblasts. Two of the three compounds showed strong activities against both bacteria and fibroblasts. The third analog was much less potent in both assays. These results suggested that the target of bactobolins might be conserved across bacteria and mammalian cells. To learn about the mechanism of bactobolin activity, we isolated four spontaneous bactobolin-resistant Bacillus subtilis mutants. We used genomic sequencing technology to show that each of the four resistant variants had mutations in rplB, which codes for the 50S ribosome-associated L2 protein. Ectopic expression of a mutant rplB gene in wild-type B. subtilis conferred bactobolin resistance. Finally, the L2 mutations did not confer resistance to other antibiotics known to interfere with ribosome function. Our data indicate that bactobolins target the L2 protein or a nearby site and that this is not the target of other antibiotics. We presume that the mammalian target of bactobolins involves the eukaryotic homolog of L2 (L8e). Currently available antibiotics target surprisingly few cellular functions, and there is a need to identify novel antibiotic targets. We have been interested in the Burkholderia thailandensis bactobolins, and we sought to learn about the target of bactobolin activity by mapping spontaneous resistance mutations in the bactobolin-sensitive Bacillus subtilis. Our results indicate that the bactobolin target is the 50S ribosome-associated L2 protein or a region of the ribosome affected by L2. Bactobolin-resistant mutants are not resistant to other known ribosome inhibitors. Our evidence indicates that bactobolins

MENA Confers Resistance to Paclitaxel in Triple-Negative Breast Cancer.

PubMed

Oudin, Madeleine J; Barbier, Lucie; Schäfer, Claudia; Kosciuk, Tatsiana; Miller, Miles A; Han, Sangyoon; Jonas, Oliver; Lauffenburger, Douglas A; Gertler, Frank B

2017-01-01

Taxane therapy remains the standard of care for triple-negative breast cancer. However, high frequencies of recurrence and progression in treated patients indicate that metastatic breast cancer cells can acquire resistance to this drug. The actin regulatory protein MENA and particularly its invasive isoform, MENA INV , are established drivers of metastasis. MENA INV expression is significantly correlated with metastasis and poor outcome in human patients with breast cancer. We investigated whether MENA isoforms might play a role in driving resistance to chemotherapeutics. We find that both MENA and MENA INV confer resistance to the taxane paclitaxel, but not to the widely used DNA-damaging agents doxorubicin or cisplatin. Furthermore, paclitaxel treatment does not attenuate growth of MENA INV -driven metastatic lesions. Mechanistically, MENA isoform expression alters the ratio of dynamic and stable microtubule populations in paclitaxel-treated cells. MENA expression also increases MAPK signaling in response to paclitaxel treatment. Decreasing ERK phosphorylation by co-treatment with MEK inhibitor restored paclitaxel sensitivity by driving microtubule stabilization in MENA isoform-expressing cells. Our results reveal a novel mechanism of taxane resistance in highly metastatic breast cancer cells and identify a combination therapy to overcome such resistance. Mol Cancer Ther; 16(1); 143-55. ©2016 AACR. ©2016 American Association for Cancer Research.

21 CFR 17.21 - Prehearing conferences.

Code of Federal Regulations, 2010 CFR

2010-04-01

... one prehearing conference at a reasonable time in advance of the hearing. (c) The presiding officer... completion of discovery; (9) The date, time, and place for the hearing; and (10) Such other matters as may tend to expedite the fair and just disposition of the proceedings. (d) The presiding officer shall...

21 CFR 17.21 - Prehearing conferences.

Code of Federal Regulations, 2011 CFR

2011-04-01

... one prehearing conference at a reasonable time in advance of the hearing. (c) The presiding officer... completion of discovery; (9) The date, time, and place for the hearing; and (10) Such other matters as may tend to expedite the fair and just disposition of the proceedings. (d) The presiding officer shall...

K13-propeller mutations confer artemisinin resistance in Plasmodium falciparum clinical isolates

PubMed Central

Straimer, Judith; Gnädig, Nina F.; Witkowski, Benoit; Amaratunga, Chanaki; Duru, Valentine; Ramadani, Arba Pramundita; Dacheux, Mélanie; Khim, Nimol; Zhang, Lei; Lam, Stephen; Gregory, Philip D.; Urnov, Fyodor D.; Mercereau-Puijalon, Odile; Benoit-Vical, Françoise; Fairhurst, Rick M.; Ménard, Didier; Fidock, David A.

2015-01-01

The emergence of artemisinin resistance in Southeast Asia imperils efforts to reduce the global malaria burden. We genetically modified the Plasmodium falciparum K13 locus using zinc-finger nucleases and measured ring-stage survival rates after drug exposure in vitro; these rates correlate with parasite clearance half-lives in artemisinin-treated patients. With isolates from Cambodia, where resistance first emerged, survival rates decreased from 13 to 49% to 0.3 to 2.4% after the removal of K13 mutations. Conversely, survival rates in wild-type parasites increased from ≤0.6% to 2 to 29% after the insertion of K13 mutations. These mutations conferred elevated resistance to recent Cambodian isolates compared with that of reference lines, suggesting a contemporary contribution of additional genetic factors. Our data provide a conclusive rationale for worldwide K13-propeller sequencing to identify and eliminate artemisinin-resistant parasites. PMID:25502314

Polar flagella rotation in Vibrio parahaemolyticus confers resistance to bacteriophage infection

PubMed Central

Zhang, Hui; Li, Lu; Zhao, Zhe; Peng, Daxin; Zhou, Xiaohui

2016-01-01

Bacteriophage has been recognized as a novel approach to treat bacterial infectious diseases. However, phage resistance may reduce the efficacy of phage therapy. Here, we described a mechanism of bacterial resistance to phage infections. In Gram-negative enteric pathogen Vibrio parahaemolyticus, we found that polar flagella can reduce the phage infectivity. Deletion of polar flagella, but not the lateral flagella, can dramatically promote the adsorption of phage to the bacteria and enhances the phage infectivity to V. parahaemolyticus, indicating that polar flagella play an inhibitory role in the phage infection. Notably, it is the rotation, not the physical presence, of polar flagella that inhibits the phage infection of V. parahaemolyticus. Strikingly, phage dramatically reduces the virulence of V. parahaemolyticus only when polar flagella were absent both in vitro and in vivo. These results indicated that polar flagella rotation is a previously unidentified mechanism that confers bacteriophage resistance. PMID:27189325

Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of deep vein thrombosis.

PubMed

Robertson, Lindsay; Kesteven, Patrick; McCaslin, James E

2015-06-30

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately 1 in 1,000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of novel oral anticoagulants (NOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the treatment of DVT. To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the treatment of DVT. The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles retrieved by electronic searches for additional citations. We included randomised controlled trials in which people with a DVT confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor for the treatment of DVT. Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third review author (PK). We performed meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent VTE and PE. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI). We included

Acquired drug resistance conferred by a KRAS gene mutation following the administration of cetuximab: a case report

PubMed Central

2013-01-01

Background Although a number of studies have reported acquired drug resistance due to administration of epidermal growth factor receptor antibody inhibitors, the underlying causes of this phenomenon remain unclear. Case presentation Here we report a case of a 75-year-old man with liver metastasis at 3 years after a successful transverse colectomy to treat KRAS wild-type colorectal cancer. While initial administration of epidermal growth factor receptor inhibitors proved effective, continued use of the same treatment resulted in new peritoneal seeding. An acquired KRAS mutation was found in a resected tissue specimen from one such area. This mutation, possibly caused by administration of epidermal growth factor receptor inhibitors, appears to have conferred drug resistance. Conclusion The present findings suggest that administration of epidermal growth factor receptor inhibitors results in an acquired KRAS mutation that confers drug resistance. PMID:24304820

PREFACE: 21st International Conference on Laser Spectroscopy - ICOLS 2013

NASA Astrophysics Data System (ADS)

Budker, Dmitry; Häffner, Hartmut; Müller, Holger

2013-12-01

The 21st International Conference on Laser Spectroscopy (ICOLS) took place at Berkeley, California on 9-14 June 2013. Following the tradition of previous meetings in this series, the conference featured about thirty invited talks broadly covering this burgeoning field of science that refuses to show any sign of saturation after more than half a century of continuous boom. In addition to the invited talks, there were two informative poster sessions, where the more than 300 ICOLS participants had an opportunity to exchange the latest scientific news and ideas while enjoying the gorgeous view of the San Francisco Bay from the vista of the Claremont Hotel, the meeting's venue. The heights of the cultural program of the meeting were excursions to several of the Bay Area gems (including the Lick observatory), as well as the conference banquet where the participants were treated to addresses by an inventor of the laser Professor Charles H Townes, a nonlinear optics pioneer Professor Erwin L Hahn, and one of the previous ICOLS chairs Professor Y R Shen. While the field of Laser Spectroscopy and the series of the bi-annual ICOLS meetings are as 'healthy' as one could imagine, the same cannot be said about the concept of published conference proceedings. With new ways to publish scientific articles and preprints, submitting papers to conference proceedings seems to be rapidly losing popularity. For this meeting, the great interest in attendance and opportunities to present is sharply contrasted with a somewhat sluggish response to the call for submission of the proceedings papers. The present collection represents a dozen or so contributions from the 'hero' invited speakers, to whom we are deeply grateful for submitting their work. We hope that this selection will faithfully convey to the readers the excitement of modern laser spectroscopy. In addition to these papers, we draw the reader's attention to the audio recordings and selected viewgraphs from the invited talks, and

QTL analysis on rice grain appearance quality, as exemplifying the typical events of transgenic or backcrossing breeding

PubMed Central

Yan, Bao; Liu, Rongjia; Li, Yibo; Wang, Yan; Gao, Guanjun; Zhang, Qinglu; Liu, Xing; Jiang, Gonghao; He, Yuqing

2014-01-01

Rice grain shape and yield are usually controlled by multiple quantitative trait loci (QTL). This study used a set of F9–10 recombinant inbred lines (RILs) derived from a cross of Huahui 3 (Bt/Xa21) and Zhongguoxiangdao, and detected 27 QTLs on ten rice chromosomes. Among them, twelve QTLs responsive for grain shape/ or yield were mostly reproducibly detected and had not yet been reported before. Interestingly, the two known genes involved in the materials, with one insect-resistant Bt gene, and the other disease-resistant Xa21 gene, were found to closely link the QTLs responsive for grain shape and weight. The Bt fragment insertion was firstly mapped on the chromosome 10 in Huahui 3 and may disrupt grain-related QTLs resulting in weaker yield performance in transgenic plants. The introgression of Xa21 gene by backcrossing from donor material into receptor Minghui 63 may also contain a donor linkage drag which included minor-effect QTL alleles positively affecting grain shape and yield. The QTL analysis on rice grain appearance quality exemplified the typical events of transgenic or backcrossing breeding. The QTL findings in this study will in the future facilitate the gene isolation and breeding application for improvement of rice grain shape and yield. PMID:25320558

QTL analysis on rice grain appearance quality, as exemplifying the typical events of transgenic or backcrossing breeding.

PubMed

Yan, Bao; Liu, Rongjia; Li, Yibo; Wang, Yan; Gao, Guanjun; Zhang, Qinglu; Liu, Xing; Jiang, Gonghao; He, Yuqing

2014-09-01

Rice grain shape and yield are usually controlled by multiple quantitative trait loci (QTL). This study used a set of F9-10 recombinant inbred lines (RILs) derived from a cross of Huahui 3 (Bt/Xa21) and Zhongguoxiangdao, and detected 27 QTLs on ten rice chromosomes. Among them, twelve QTLs responsive for grain shape/ or yield were mostly reproducibly detected and had not yet been reported before. Interestingly, the two known genes involved in the materials, with one insect-resistant Bt gene, and the other disease-resistant Xa21 gene, were found to closely link the QTLs responsive for grain shape and weight. The Bt fragment insertion was firstly mapped on the chromosome 10 in Huahui 3 and may disrupt grain-related QTLs resulting in weaker yield performance in transgenic plants. The introgression of Xa21 gene by backcrossing from donor material into receptor Minghui 63 may also contain a donor linkage drag which included minor-effect QTL alleles positively affecting grain shape and yield. The QTL analysis on rice grain appearance quality exemplified the typical events of transgenic or backcrossing breeding. The QTL findings in this study will in the future facilitate the gene isolation and breeding application for improvement of rice grain shape and yield.

miR-21 Contributes to Xenon-conferred Amelioration of Renal Ischemia–Reperfusion Injury in Mice

PubMed Central

Jia, Ping; Teng, Jie; Zou, Jianzhou; Fang, Yi; Zhang, Xiaoyan; Bosnjak, Zeljko J.; Liang, Mingyu; Ding, Xiaoqiang

2015-01-01

Background MicroRNAs participate in the regulation of numerous physiological and disease processes. The in vivo role of microRNAs in anesthetics-conferred organoprotection is unknown. Methods Mice were exposed for 2 h to either 70% xenon, or 70% nitrogen, 24 h before the induction of renal ischemia-reperfusion injury. The role of microRNA, miR-21, in renal protection conferred by the delayed xenon preconditioning was examined using in vivo knockdown of miR-21 and analysis of miR-21 target pathways. Results Xenon preconditioning provided morphologic and functional protection against renal ischemia-reperfusion injury (n = 6), characterized by attenuation of renal tubular damage, apoptosis, and oxidative stress. Xenon preconditioning significantly increased the expression of miR-21 in the mouse kidney. A locked nucleic acid-modified anti–miR-21, given before xenon preconditioning, knocked down miR-21 effectively, and exacerbated subsequent renal ischemia-reperfusion injury. Mice treated with anti–miR-21 and ischemia-reperfusion injury showed significantly higher serum creatinine than antiscrambled oligonucleotides-treated mice, 24 h after ischemia-reperfusion (1.37 ± 0.28 vs. 0.81 ± 0.14 mg/dl; n = 5; P < 0.05). Knockdown of miR-21 induced significant up-regulation of programmed cell death protein 4 and phosphatase and tensin homolog deleted on chromosome 10, two proapoptotic target effectors of miR-21, and resulted in significant down-regulation of phosphorylated protein kinase B and increased tubular cell apoptosis. In addition, xenon preconditioning up-regulated hypoxia-inducible factor-1α and its downstream effector vascular endothelial growth factor in a time-dependent manner. Knockdown of miR-21 resulted in a significant decrease of hypoxia-inducible factor-1α. Conclusions These results indicate that miR-21 contributes to the renoprotective effect of xenon preconditioning. PMID:23681145

miR-21 contributes to xenon-conferred amelioration of renal ischemia-reperfusion injury in mice.

PubMed

Jia, Ping; Teng, Jie; Zou, Jianzhou; Fang, Yi; Zhang, Xiaoyan; Bosnjak, Zeljko J; Liang, Mingyu; Ding, Xiaoqiang

2013-09-01

MicroRNAs participate in the regulation of numerous physiological and disease processes. The in vivo role of microRNAs in anesthetics-conferred organoprotection is unknown. Mice were exposed for 2 h to either 70% xenon, or 70% nitrogen, 24 h before the induction of renal ischemia-reperfusion injury. The role of microRNA, miR-21, in renal protection conferred by the delayed xenon preconditioning was examined using in vivo knockdown of miR-21 and analysis of miR-21 target pathways. Xenon preconditioning provided morphologic and functional protection against renal ischemia-reperfusion injury (n = 6), characterized by attenuation of renal tubular damage, apoptosis, and oxidative stress. Xenon preconditioning significantly increased the expression of miR-21 in the mouse kidney. A locked nucleic acid-modified anti-miR-21, given before xenon preconditioning, knocked down miR-21 effectively, and exacerbated subsequent renal ischemia-reperfusion injury. Mice treated with anti-miR-21 and ischemia-reperfusion injury showed significantly higher serum creatinine than antiscrambled oligonucleotides-treated mice, 24 h after ischemia-reperfusion (1.37 ± 0.28 vs. 0.81 ± 0.14 mg/dl; n = 5; P < 0.05). Knockdown of miR-21 induced significant up-regulation of programmed cell death protein 4 and phosphatase and tensin homolog deleted on chromosome 10, two proapoptotic target effectors of miR-21, and resulted in significant down-regulation of phosphorylated protein kinase B and increased tubular cell apoptosis. In addition, xenon preconditioning up-regulated hypoxia-inducible factor-1α and its downstream effector vascular endothelial growth factor in a time-dependent manner. Knockdown of miR-21 resulted in a significant decrease of hypoxia-inducible factor-1α. These results indicate that miR-21 contributes to the renoprotective effect of xenon preconditioning.

Precisely mapping a major gene conferring resistance to Hessian fly in bread wheat using genotyping-by-sequencing

USDA-ARS?s Scientific Manuscript database

Background One of the reasons hard red winter wheat cultivar ‘Duster’ (PI 644016) is widely grown in the southern Great Plains is that it confers a consistently high level of resistance to biotype GP of Hessian fly (Hf). However, little is known about the genetic mechanism underlying Hf resistance i...

Proceedings of the International Conference on Counseling in the 21st Century (4th, Vancouver, Canada, July 21-23, 1994).

ERIC Educational Resources Information Center

Evraiff, Bill, Comp.; Evraiff, Lois, Comp.

The fourth international conference focused on two issues for counseling in the 21st century. The first issue concerned physical and mental health. Presentations covered such topics as: counseling college students concerning their attitudes and beliefs about HIV/AIDS; United States health care reform and how it affects people with disabilities;…

Two members of the mouse mdr gene family confer multidrug resistance with overlapping but distinct drug specificities.

PubMed Central

Devault, A; Gros, P

1990-01-01

We report the cloning and functional analysis of a complete clone for the third member of the mouse mdr gene family, mdr3. Nucleotide and predicted amino acid sequence analyses showed that the three mouse mdr genes encode highly homologous membrane glycoproteins, which share the same length (1,276 residues), the same predicted functional domains, and overall structural arrangement. Regions of divergence among the three proteins are concentrated in discrete segments of the predicted polypeptides. Sequence comparison indicated that the three mouse mdr genes were created from a common ancestor by two independent gene duplication events, the most recent one producing mdr1 and mdr3. When transfected and overexpressed in otherwise drug-sensitive cells, the mdr3 gene, like mdr1 and unlike mdr2, conferred multidrug resistance to these cells. In independently derived transfected cell clones expressing similar amounts of either MDR1 or MDR3 protein, the drug resistance profile conferred by mdr3 was distinct from that conferred by mdr1. Cells transfected with and expressing MDR1 showed a marked 7- to 10-fold preferential resistance to colchicine and Adriamycin compared with cells expressing equivalent amounts of MDR3. Conversely, cells transfected with and expressing MDR3 showed a two- to threefold preferential resistance to actinomycin D over their cellular counterpart expressing MDR1. These results suggest that MDR1 and MDR3 are membrane-associated efflux pumps which, in multidrug-resistant cells and perhaps normal tissues, have overlapping but distinct substrate specificities. Images PMID:1969610

L2₁ and XA Ordering Competition in Hafnium-Based Full-Heusler Alloys Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb).

PubMed

Wang, Xiaotian; Cheng, Zhenxiang; Wang, Wenhong

2017-10-20

For theoretical designing of full-Heusler based spintroinc materials, people have long believed in the so-called Site Preference Rule (SPR). Very recently, according to the SPR, there are several studies on XA-type Hafnium-based Heusler alloys X₂YZ, i.e., Hf₂VAl, Hf₂CoZ (Z = Ga, In) and Hf₂CrZ (Z = Al, Ga, In). In this work, a series of Hf₂-based Heusler alloys, Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb), were selected as targets to study the site preferences of their atoms by first-principle calculations. It has been found that all of them are likely to exhibit the L2₁-type structure instead of the XA one. Furthermore, we reveal that the high values of spin-polarization of XA-type Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb) alloys have dropped dramatically when they form the L2₁-type structure. Also, we prove that the electronic, magnetic, and physics nature of these alloys are quite different, depending on the L2₁-type or XA-type structures.

Comparative mapping of powdery mildew resistance gene Pm21 and functional characterization of resistance-related genes in wheat.

PubMed

He, Huagang; Zhu, Shanying; Jiang, Zhengning; Ji, Yaoyong; Wang, Feng; Zhao, Renhui; Bie, Tongde

2016-04-01

The powdery mildew resistance gene Pm21 was physically and comparatively mapped by newly developed markers. Seven candidate genes were verified to be required for Pm21 -mediated resistance to wheat powdery mildew. Pm21, a gene derived from wheat wild relative Dasypyrum villosum, has been transferred into common wheat and widely utilized in wheat resistance breeding for powdery mildew. Previously, Pm21 has been located to the bin FL0.45-0.58 of 6VS by using deletion stocks. However, its fine mapping is still a hard work. In the present study, 30 gene-derived 6VS-specific markers were obtained based on the collinearity among genomes of Brachypodium distachyon, Oryza and Triticeae, and then physically and comparatively mapped in the bin FL0.45-0.58 and its nearby chromosome region. According to the maps, the bin FL0.45-0.58 carrying Pm21 was closely flanked by the markers 6VS-03 and 6VS-23, which further narrowed the orthologous regions to 1.06 Mb in Brachypodium and 1.38 Mb in rice, respectively. Among the conserved genes shared by Brachypodium and rice, four serine/threonine protein kinase genes (DvMPK1, DvMLPK, DvUPK and DvPSYR1), one protein phosphatase gene (DvPP2C) and two transcription factor genes (DvGATA and DvWHY) were confirmed to be required for Pm21-mediated resistance to wheat powdery mildew by barley stripe mosaic virus-induced gene silencing (BSMV-VIGS) and transcriptional pattern analyses. In summary, this study gives new insights into the genetic basis of the Pm21 locus and the disease resistance pathways mediated by Pm21.

qnrA6 genetic environment and quinolone resistance conferred on Proteus mirabilis.

PubMed

Jayol, Aurélie; Janvier, Frédéric; Guillard, Thomas; Chau, Françoise; Mérens, Audrey; Robert, Jérôme; Fantin, Bruno; Berçot, Béatrice; Cambau, Emmanuelle

2016-04-01

To determine the genetic location and environment of the qnrA6 gene in Proteus mirabilis PS16 where it was first described and to characterize the quinolone resistance qnrA6 confers. Transformation experiments and Southern blotting were performed for plasmid and genomic DNA of P. mirabilis PS16 to determine the qnrA6 location. Combinatorial PCRs with primers in qnrA6 and genes usually surrounding qnrA genes were used to determine the genetic environment. The qnrA6 coding region, including or not the promoter region, was cloned into vectors pTOPO and pBR322 and the MICs of six quinolones were measured for transformants of Escherichia coli TOP10 and P. mirabilis ATCC 29906 Rif(R). qnrA6 was shown to be chromosomally encoded in P. mirabilis PS16 and its genetic environment was 81%-87% similar to that of qnrA2 in the Shewanella algae chromosome. The 5138 bp region up- and downstream of qnrA6 contained an IS10 sequence surrounded by two ISCR1. This resulted in qnrA6 being displaced 1.9 kb from its native promoter but supplied a promoter present in ISCR1. qnrA6 cloned into pTOPO and pBR322 conferred a 4-32-fold increase in fluoroquinolone MICs when expressed in E. coli but only 2-3-fold in P. mirabilis. When including the promoter region, a further increase in resistance was observed in both species, reaching MIC values above clinical breakpoints for only P. mirabilis. qnrA6 is the first chromosomally located qnrA gene described in Enterobacteriaceae. The quinolone resistance conferred by qnrA6 depends on the proximity of an efficient promoter and the host strain where it is expressed. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Rapidly evolving R genes in diverse grass species confer resistance to rice blast disease

PubMed Central

Yang, Sihai; Li, Jing; Zhang, Xiaohui; Zhang, Qijun; Huang, Ju; Chen, Jian-Qun; Hartl, Daniel L.; Tian, Dacheng

2013-01-01

We show that the genomes of maize, sorghum, and brachypodium contain genes that, when transformed into rice, confer resistance to rice blast disease. The genes are resistance genes (R genes) that encode proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains (NBS–LRR proteins). By using criteria associated with rapid molecular evolution, we identified three rapidly evolving R-gene families in these species as well as in rice, and transformed a randomly chosen subset of these genes into rice strains known to be sensitive to rice blast disease caused by the fungus Magnaporthe oryzae. The transformed strains were then tested for sensitivity or resistance to 12 diverse strains of M. oryzae. A total of 15 functional blast R genes were identified among 60 NBS–LRR genes cloned from maize, sorghum, and brachypodium; and 13 blast R genes were obtained from 20 NBS–LRR paralogs in rice. These results show that abundant blast R genes occur not only within species but also among species, and that the R genes in the same rapidly evolving gene family can exhibit an effector response that confers resistance to rapidly evolving fungal pathogens. Neither conventional evolutionary conservation nor conventional evolutionary convergence supplies a satisfactory explanation of our findings. We suggest a unique mechanism termed “constrained divergence,” in which R genes and pathogen effectors can follow only limited evolutionary pathways to increase fitness. Our results open avenues for R-gene identification that will help to elucidate R-gene vs. effector mechanisms and may yield new sources of durable pathogen resistance. PMID:24145399

Novel Tn916-like elements confer aminoglycoside/macrolide co-resistance in clinical isolates of Streptococcus gallolyticus ssp. gallolyticus.

PubMed

Kambarev, Stanimir; Pecorari, Frédéric; Corvec, Stéphane

2018-02-09

Streptococcus gallolyticus ssp. gallolyticus (Sgg) is a commensal bacterium and an opportunistic pathogen. In humans it has been clinically associated with the incidence of colorectal cancer (CRC) and epidemiologically recognized as an emerging cause of infective endocarditis (IE). The standard therapy of Sgg includes the administration of a penicillin in combination with an aminoglycoside. Even though penicillin-resistant isolates have still not been reported, epidemiological studies have shown that this microbe is a reservoir of multiple acquired genes, conferring resistance to tetracyclines, aminoglycosides, macrolides and glycopeptides. However, the underlying antibiotic resistance mobilome of Sgg remains poorly understood. To investigate the mobile genetic basis of antibiotic resistance in multiresistant clinical Sgg. Isolate NTS31106099 was recovered from a patient with IE and CRC at Nantes University Hospital, France and studied by Illumina WGS and comparative genomics. Molecular epidemiology of the identified mobile element(s) was performed using antibiotic susceptibility testing (AST), PCR, PFGE and WGS. Mobility was investigated by PCR and filter mating. Two novel conjugative transposons, Tn6263 and Tn6331, confer aminoglycoside/macrolide co-resistance in clinical Sgg. They display classical family Tn916/Tn1545 modular architecture and harbour an aph(3')-III→sat4→ant(6)-Ia→erm(B) multiresistance gene cluster, related to pRE25 of Enterococcus faecium. These and/or closely related elements are highly prevalent among genetically heterogeneous clinical isolates of Sgg. Previously unknown Tn916-like mobile genetic elements conferring aminoglycoside/macrolide co-resistance make Sgg, collectively with other gut Firmicutes such as enterococci and eubacteria, a potential laterally active reservoir of these antibiotic resistance determinants among the mammalian gastrointestinal microbiota. © The Author(s) 2018. Published by Oxford University Press on behalf

The S230R Integrase Substitution Associated with Viral Rebound during DTG Monotherapy Confers Low Levels INSTI Drug Resistance.

PubMed

Pham, Hanh T; Labrie, Lydia; Wijting, Ingeborg E A; Hassounah, Said; Lok, Ka Yee; Portna, Inna; Goring, Mark; Han, Yingshan; Lungu, Cynthia; van der Ende, Marchina E; Brenner, Bluma G; Boucher, Charles A; Rijnders, Bart J A; van Kampen, Jeroen J A; Mesplède, Thibault; Wainberg, Mark A

2018-03-29

Dolutegravir (DTG) is an integrase strand-transfer inhibitor (INSTI) used for treatment of HIV-infected individuals. Due to its high genetic barrier to resistance, DTG has been clinically investigated as maintenance monotherapy to maintain viral suppression and to reduce complication and healthcare costs. Our study aims to explain the underlying mechanism related to the emergence of a S230R substitution in patients who experienced virological failure while using DTG monotherapy. We evaluated the effect of S230R substitution in regard to IN enzyme activity, viral infectivity, replicative capacity and susceptibility to different INSTIs by biochemical and cell-based assays. S230R substitution conferred 63% reduction in enzyme efficiency. The S230R virus was 1.29-fold less infectious than wildtype (WT), but could replicate in PM1 cells without significant delay. Resistance levels against DTG, CAB, RAL and EVG in tissue culture were 3.85-, 3.72-, 1.52-, and 1.21-fold, respectively. Our data indicate that the S230R substitution is comparable to the previously reported R263K in some respects. Virological failure under DTG monotherapy can occur through the development of such S230R or R263K mutations without the need for high levels DTG resistance.

A novel resistance gene, lnu(H), conferring resistance to lincosamides in Riemerella anatipestifer CH-2.

PubMed

Luo, Hong-Yan; Liu, Ma-Feng; Wang, Ming-Shu; Zhao, Xin-Xin; Jia, Ren-Yong; Chen, Shun; Sun, Kun-Feng; Yang, Qiao; Wu, Ying; Chen, Xiao-Yue; Biville, Francis; Zou, Yuan-Feng; Jing, Bo; Cheng, An-Chun; Zhu, De-Kang

2018-01-01

The Gram-negative bacterium Riemerella anatipestifer CH-2 is resistant to lincosamides, having a lincomycin (LCM) minimum inhibitory concentration (MIC) of 128 µg/mL. The G148_1775 gene of R. anatipestifer CH-2, designated lnu(H), encodes a 260-amino acid protein with ≤41% identity to other reported lincosamide nucleotidylyltransferases. Escherichia coli Rosetta TM (DE3) containing the pBAD24-lnu(H) plasmid showed four- and two-fold increases in the MICs of LCM and clindamycin (CLI), respectively. A kinetic assay of the purified Lnu(H) enzyme for LCM and CLI showed that the protein could inactive lincosamides. Mass spectrometry analysis demonstrated that the Lnu(H) enzyme catalysed adenylylation of lincosamides. In addition, an lnu(H) gene deletion strain exhibited 512- and 32-fold decreases in LCM and CLI MICs, respectively. The wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu(H) gene. The transformant R. anatipestifer ATCC 11845 [lnu(H)] acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, among 175 R. anatipestifer field isolates, 56 (32.0%) were positive for the lnu(H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidylyltransferase that inactivates LCM and CLI by nucleotidylylation, thus conferring high-level lincosamide resistance to R. anatipestifer CH-2. Copyright © 2017. Published by Elsevier B.V.

Phosphine resistance does not confer cross-resistance to sulfuryl fluoride in four major stored grain insect pests.

PubMed

Jagadeesan, Rajeswaran; Nayak, Manoj K

2017-07-01

Susceptibility to phosphine (PH 3 ) and sulfuryl fluoride (SF) and cross-resistance to SF were evaluated in two life stages (eggs and adults) of key grain insect pests, Rhyzopertha dominca (F.), Sitophilus oryzae (L.), Cryptolestes ferrugineus (Stephens), and Tribolium castaneum (Herbst). This study was performed with an aim to integrate SF into phosphine resistance management programmes in Australia. Characterisation of susceptibility and resistance to phosphine in eggs and adults showed that C. ferrugineus was the most tolerant as well as resistant species. Mortality responses of eggs and adults to SF at 25 °C revealed T. castaneum to be the most tolerant species followed by S. oryzae, C. ferrugineus and R. dominica. A high dose range of SF, 50.8-62.2 mg L -1 over 48 h, representing c (concentration) × t (time) products of 2438-2985 gh m -3 , was required for complete control of eggs of T. castaneum, whereas eggs of the least tolerant R. dominca required only 630 gh m -3 for 48 h (13.13 mg L -1 ). Mortality response of eggs and adults of phosphine-resistant strains to SF in all four species confirmed the lack of cross-resistance to SF. Our research concludes that phosphine resistance does not confer cross-resistance to SF in grain insect pests irrespective of the variation in levels of tolerance to SF itself or resistance to phosphine in their egg and adult stages. While our study confirms that SF has potential as a 'phosphine resistance breaker', the observed higher tolerance in eggs stresses the importance of developing SF fumigation protocols with longer exposure periods. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Mhc supertypes confer both qualitative and quantitative resistance to avian malaria infections in a wild bird population

PubMed Central

Sepil, Irem; Lachish, Shelly; Hinks, Amy E.; Sheldon, Ben C.

2013-01-01

Major histocompatibility complex (Mhc) genes are believed to play a key role in the genetic basis of disease control. Although numerous studies have sought links between Mhc and disease prevalence, many have ignored the ecological and epidemiological aspects of the host–parasite interaction. Consequently, interpreting associations between prevalence and Mhc has been difficult, whereas discriminating alleles for qualitative resistance, quantitative resistance and susceptibility remains challenging. Moreover, most studies to date have quantified associations between genotypes and disease status, overlooking the complex relationship between genotype and the properties of the Mhc molecule that interacts with parasites. Here, we address these problems and demonstrate avian malaria (Plasmodium) parasite species-specific associations with functional properties of Mhc molecules (Mhc supertypes) in a wild great tit (Parus major) population. We further show that correctly interpreting these associations depends crucially on understanding the spatial variation in risk of infection and the fitness effects of infection. We report that a single Mhc supertype confers qualitative resistance to Plasmodium relictum, whereas a different Mhc supertype confers quantitative resistance to Plasmodium circumflexum infections. Furthermore, we demonstrate common functional properties of Plasmodium-resistance alleles in passerine birds, suggesting this is a model system for parasite–Mhc associations in the wild. PMID:23516242

GRP78 confers the resistance to 5-FU by activating the c-Src/LSF/TS axis in hepatocellular carcinoma.

PubMed

Gu, Yan-jiao; Li, Hong-dan; Zhao, Liang; Zhao, Song; He, Wu-bin; Rui, Li; Su, Chang; Zheng, Hua-chuan; Su, Rong-jian

2015-10-20

5-FU is a common first-line chemotherapeutic drug for the treatment of hepatocellular carcinoma. However the development of acquired resistance to 5-FU confines its clinical usages. Although this phenomenon has been the subject of intense investigation, the exact mechanism of acquired resistance to 5-FU remains elusive. Here, we report that over-expression of GRP78 contributes to acquired resistance to 5-FU in HCC by up-regulating the c-Src/LSF/TS axis. Moreover, we found that the resistance to 5-FU conferred by GRP78 is mediated by its ATPase domain. The ATPase domain differentially increased the expression of LSF, TS and promoted the phosphorylation of ERK and Akt. We further identified that GRP78 interacts physically with c-Src through its ATPase domain and promotes the phosphorylation of c-Src, which in turn increases the expression of LSF in the nucleus. Together, GRP78 confers the resistance to 5-FU by up-regulating the c-Src/LSF/TS axis via its ATPase domain.

Funding Proposal for EDISON’20 Conference Buffalo, New York, 07/17 - 07/21, 2017

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

Bird, Jonathan

EDISON’20 – The 20th International Conference on Electron Dynamics in Semiconductors, Optoe- lectronics and Nanostructures – was held at the Hyatt Regency Hotel, Buffalo, NY from July 17 – 21, 2017. The technical focus of this conference was on the fundamental physics and applications of nonequilibrium classical and quantum carrier dynamics in semiconductors, optoelectronic de- vices, and nanostructures. This five-day, single-session conference featured a program consisting of some 15 invited talks, given by internationally-renowned academics from the U.S., Europe, and Japan. Their keynote presentations covered topics including: terahertz phenomena in semiconductors; quantum transport in novel two-dimensional semiconductors; topological insulators; mesoscopicmore » phenomena in semiconductors, and; semiconductor spintronics. The invited papers were supplemented by some 30 contributed talks, selected from almost 120 abstracts submitted in response to the conference’s call for papers, and by two poster sessions that each consisted of close to 40 different reports. This critical mass in terms of scientific content ensured a highly vibrant conference, in which leaders in the field had the opportunity to interact closely with early-career scientists.« less

Activation of RAS family members confers resistance to ROS1 targeting drugs

PubMed Central

Cargnelutti, Marilisa; Corso, Simona; Pergolizzi, Margherita; Mévellec, Laurence; Aisner, Dara L.; Dziadziuszko, Rafal; Varella-Garcia, Marileila; Comoglio, Paolo M.; Doebele, Robert C.; Vialard, Jorge; Giordano, Silvia

2015-01-01

The ROS1 tyrosine kinase is activated in lung cancer as a consequence of chromosomal rearrangement. Although high response rates and disease control have been observed in lung cancer patients bearing rearranged ROS1 tumors (ROS1+) treated with the kinase inhibitor crizotinib, many of these patients eventually relapse. To identify mechanisms of resistance to ROS1 inhibitors we generated resistant cells from HCC78 lung cancer cells bearing the SLC34A2-ROS1 rearrangement. We found that activation of the RAS pathway in the HCC78 cell model, due to either KRAS/NRAS mutations or to KRAS amplification, rendered the cells resistant to ROS1 inhibition. These cells were cross-resistant to different ROS1 inhibitors, but sensitive to inhibitors of the RAS signaling pathway. Interestingly, we identified focal KRAS amplification in a biopsy of a tumor from a patient that had become resistant to crizotinib treatment. Altogether our data suggest that the activation of members of the RAS family can confer resistance to ROS1 inhibitors. This has important clinical implications as: (i) RAS genetic alterations in ROS1+ primary tumors are likely negative predictors of efficacy for targeted drugs and (ii) this kind of resistance is unlikely to be overcome by the use of more specific or more potent ROS1 targeting drugs. PMID:25691052

Combination of all-stage and high-temperature adult-plant resistance QTL confers high-level, durable resistance to stripe rust in winter wheat cultivar Madsen.

PubMed

Liu, L; Wang, M N; Feng, J Y; See, D R; Chao, S M; Chen, X M

2018-05-24

Wheat cultivar Madsen has a new gene on the short arm of chromosome 1A and two QTL for all-stage resistance and three QTL for high-temperature adult-plant resistance that in combination confer high-level, durable resistance to stripe rust. Wheat cultivar Madsen has maintained a high-level resistance to stripe rust over 30 years. To map quantitative trait loci (QTL) underlying the high-level, durable resistance, 156 recombinant inbred lines (RILs) developed from cross Avocet S × Madsen were phenotyped with selected races of Puccinia striiformis f. sp. tritici in the greenhouse seedling tests, and in naturally infected fields during 2015-2017. The RILs were genotyped by SSR and SNP markers from genotyping by sequencing and the 90 K wheat SNP chip. Three QTL for all-stage resistance were mapped on chromosomes 1AS, 1BS and 2AS, and two QTL for high-temperature adult-plant (HTAP) resistance were mapped on 3BS and 6BS. The most effective QTL on 2AS, explaining 8.97-23.10% of the phenotypic variation in seedling tests and 8.60-71.23% in field tests, contained Yr17 for all-stage resistance and an additional gene for HTAP resistance. The 6BS QTL, detected in all field tests, was identified as Yr78. The 1AS QTL, conferring all-stage resistance, was identified as a new gene, which explained 20.45 and 30.23% of variation in resistance to races PSTv-37 and PSTv-40, respectively, and contributed significantly to field resistance at Pullman in 2015-2017, but was not detected at Mount Vernon. The interactions among QTL were mostly additive, and RILs with all five QTL had the highest level of resistance in the field, similar to Madsen. Genotyping 148 US Pacific Northwest wheat cultivars with markers for the 1AS, 2AS and 6BS QTL validated the genes and markers, and indicated their usefulness for marker-assisted selection.

Increased plasma FGF21 level as an early biomarker for insulin resistance and metabolic disturbance in obese insulin-resistant rats.

PubMed

Tanajak, Pongpan; Pongkan, Wanpitak; Chattipakorn, Siriporn C; Chattipakorn, Nipon

2018-05-01

Propose: To investigate the temporal relationship between plasma fibroblast growth factor 21 levels, insulin resistance, metabolic dysfunction and cardiac fibroblast growth factor 21 resistance in long-term high-fat diet-induced obese rats. In total, 36 male Wistar rats were fed with either a normal diet or high-fat diet for 12 weeks. Blood was collected from the tail tip, and plasma was used to determine metabolic profiles and fibroblast growth factor 21 levels. Rats were sacrificed at weeks 4, 8 and 12, and the hearts were rapidly removed for the determination of cardiac fibroblast growth factor 21 signalling pathways. Body weight and plasma fibroblast growth factor 21 levels were increased after 4 weeks of consumption of a high-fat diet. At weeks 8 and 12, high-fat diet rats had significantly increased body weight and plasma fibroblast growth factor 21 levels, together with increased plasma insulin, HOMA index, area under the curve of glucose, plasma total cholesterol, plasma low-density lipoprotein cholesterol, serum malondialdehyde and cardiac malondialdehyde levels. However, plasma high-density lipoprotein cholesterol levels and cardiac fibroblast growth factor 21 signalling proteins (p-FGFR1 Tyr 154 , p-ERK1/2 Thr 202 /Tyr 204 and p-Akt Ser 473 ) were decreased, compared with normal diet rats. These findings suggest that plasma fibroblast growth factor 21 levels could be an early predictive biomarker prior to the development of insulin resistance, metabolic disturbance and cardiac fibroblast growth factor 21 resistance.

The wheat Lr34 multipathogen resistance gene confers resistance to anthracnose and rust in sorghum.

PubMed

Schnippenkoetter, Wendelin; Lo, Clive; Liu, Guoquan; Dibley, Katherine; Chan, Wai Lung; White, Jodie; Milne, Ricky; Zwart, Alexander; Kwong, Eunjung; Keller, Beat; Godwin, Ian; Krattinger, Simon G; Lagudah, Evans

2017-11-01

The ability of the wheat Lr34 multipathogen resistance gene (Lr34res) to function across a wide taxonomic boundary was investigated in transgenic Sorghum bicolor. Increased resistance to sorghum rust and anthracnose disease symptoms following infection with the biotrophic pathogen Puccinia purpurea and the hemibiotroph Colletotrichum sublineolum, respectively, occurred in transgenic plants expressing the Lr34res ABC transporter. Transgenic sorghum lines that highly expressed the wheat Lr34res gene exhibited immunity to sorghum rust compared to the low-expressing single copy Lr34res genotype that conferred partial resistance. Pathogen-induced pigmentation mediated by flavonoid phytoalexins was evident on transgenic sorghum leaves following P. purpurea infection within 24-72 h, which paralleled Lr34res gene expression. Elevated expression of flavone synthase II, flavanone 4-reductase and dihydroflavonol reductase genes which control the biosynthesis of flavonoid phytoalexins characterized the highly expressing Lr34res transgenic lines 24-h post-inoculation with P. purpurea. Metabolite analysis of mesocotyls infected with C. sublineolum showed increased levels of 3-deoxyanthocyanidin metabolites were associated with Lr34res expression, concomitant with reduced symptoms of anthracnose. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of pulmonary embolism.

PubMed

Robertson, Lindsay; Kesteven, Patrick; McCaslin, James E

2015-12-04

Pulmonary embolism is a potentially life-threatening condition in which a clot can travel from the deep veins, most commonly in the leg, up to the lungs. Previously, a pulmonary embolism was treated with the anticoagulants heparin and vitamin K antagonists. Recently, however, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the long-term treatment (minimum duration of three months) of pulmonary embolism. To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the long-term treatment of pulmonary embolism. The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). Clinical trials databases were also searched for details of ongoing or unpublished studies. We searched the reference lists of relevant articles retrieved by electronic searches for additional citations. We included randomised controlled trials in which patients with a pulmonary embolism confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor for the long-term (minimum duration three months) treatment of pulmonary embolism. Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third author (PK). We used meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent venous thromboembolism and pulmonary embolism. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes

Conference of University Administrators Conference Proceedings (12th, Surrey, England, March 21-23, 1985).

ERIC Educational Resources Information Center

Conference of Univ. Administrators.

Conference proceedings for the Conference of University Administrators include summaries of conference sessions, along with Austin Pearce's paper, "The Needs of Industry: What Are They?" Sessions focused on: forming a university company, financial diversification, financial modeling, stock exchange investment and universities, funding of…

FabH Mutations Confer Resistance to FabF-Directed Antibiotics in Staphylococcus aureus

PubMed Central

Parsons, Joshua B.; Yao, Jiangwei; Frank, Matthew W.

2014-01-01

Delineating the mechanisms for genetically acquired antibiotic resistance is a robust approach to target validation and anticipates the evolution of clinical drug resistance. This study defines a spectrum of mutations in fabH that render Staphylococcus aureus resistant to multiple natural products known to inhibit the elongation condensing enzyme (FabF) of bacterial type II fatty acid synthesis. Twenty independently isolated clones resistant to platensimycin, platencin, or thiolactomycin were isolated. All mutants selected against one antibiotic were cross-resistant to the other two antibiotics. Mutations were not detected in fabF, but the resistant strains harbored missense mutations in fabH. The altered amino acids clustered in and around the FabH active-site tunnel. The mutant FabH proteins were catalytically compromised based on the low activities of the purified enzymes, a fatty acid-dependent growth phenotype, and elevated expression of the fabHF operon in the mutant strains. Independent manipulation of fabF and fabH expression levels showed that the FabH/FabF activity ratio was a major determinant of antibiotic sensitivity. Missense mutations that reduce FabH activity are sufficient to confer resistance to multiple antibiotics that bind to the FabF acyl-enzyme intermediate in S. aureus. PMID:25403676

Polymorphisms in Gag spacer peptide 1 confer varying levels of resistance to the HIV- 1 maturation inhibitor bevirimat.

PubMed

Adamson, Catherine S; Sakalian, Michael; Salzwedel, Karl; Freed, Eric O

2010-04-20

The maturation inhibitor bevirimat (BVM) potently inhibits human immunodeficiency virus type 1 (HIV-1) replication by blocking capsid-spacer peptide 1 (CA-SP1) cleavage. Recent clinical trials demonstrated that a significant proportion of HIV-1-infected patients do not respond to BVM. A patient's failure to respond correlated with baseline polymorphisms at SP1 residues 6-8. In this study, we demonstrate that varying levels of BVM resistance are associated with point mutations at these residues. BVM susceptibility was maintained by SP1-Q6A, -Q6H and -T8A mutations. However, an SP1-V7A mutation conferred high-level BVM resistance, and SP1-V7M and T8Delta mutations conferred intermediate levels of BVM resistance. Future exploitation of the CA-SP1 cleavage site as an antiretroviral drug target will need to overcome the baseline variability in the SP1 region of Gag.

The NB-LRR gene Pm60 confers powdery mildew resistance in wheat.

PubMed

Zou, Shenghao; Wang, Huan; Li, Yiwen; Kong, Zhaosheng; Tang, Dingzhong

2018-04-01

Powdery mildew is one of the most devastating diseases of wheat. To date, few powdery mildew resistance genes have been cloned from wheat due to the size and complexity of the wheat genome. Triticum urartu is the progenitor of the A genome of wheat and is an important source for powdery mildew resistance genes. Using molecular markers designed from scaffolds of the sequenced T. urartu accession and standard map-based cloning, a powdery mildew resistance locus was mapped to a 356-kb region, which contains two nucleotide-binding and leucine-rich repeat domain (NB-LRR) protein-encoding genes. Virus-induced gene silencing, single-cell transient expression, and stable transformation assays demonstrated that one of these two genes, designated Pm60, confers resistance to powdery mildew. Overexpression of full-length Pm60 and two allelic variants in Nicotiana benthamiana leaves induced hypersensitive cell death response, but expression of the coiled-coil domain alone was insufficient to induce hypersensitive response. Yeast two-hybrid, bimolecular fluorescence complementation and luciferase complementation imaging assays showed that Pm60 protein interacts with its neighboring NB-containing protein, suggesting that they might be functionally related. The identification and cloning of this novel wheat powdery mildew resistance gene will facilitate breeding for disease resistance in wheat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Determination if a product is water resistant or very water resistant. 352.76 Section 352.76 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE SUNSCREEN DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE [STAYED INDEFINITELY] Testing...

21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Determination if a product is water resistant or very water resistant. 352.76 Section 352.76 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE SUNSCREEN DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE [STAYED INDEFINITELY] Testing...

21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Determination if a product is water resistant or very water resistant. 352.76 Section 352.76 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE SUNSCREEN DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE [STAYED INDEFINITELY] Testing...

21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Determination if a product is water resistant or very water resistant. 352.76 Section 352.76 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE SUNSCREEN DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE [STAYED INDEFINITELY] Testing...

21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 5 2013-04-01 2013-04-01 false Determination if a product is water resistant or very water resistant. 352.76 Section 352.76 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE SUNSCREEN DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE [STAYED INDEFINITELY] Testing...

Reproducibility of the anti-Factor Xa and anti-Factor IIa assays applied to enoxaparin solution.

PubMed

Martinez, Céline; Savadogo, Adama; Agut, Christophe; Anger, Pascal

2013-01-01

Enoxaparin is a widely used subcutaneously administered antithrombotic agent comprising a complex mixture of glycosaminoglycan chains. Owing to this complexity, its antithrombotic potency cannot be defined by physicochemical methods and is therefore evaluated using an enzymatic assay of anti-Xa and anti-IIa activity. Maintaining consistent anti-Xa activity in the final medicinal product allows physicians to ensure administration of the appropriate dosage to their patients. Bioassays are usually complex and display poorer reproducibility than physicochemical tests such as HPLC assays. Here, we describe the implementation of a common robotic platform and standard release potency testing procedures for enoxaparin sodium injection (Lovenox, Sanofi, Paris, France) products at seven quality control sites within Sanofi. Qualification and analytical procedures, as well as data handling, were optimized and harmonized to improve assay reproducibility. An inter-laboratory study was performed in routine-release conditions. The coefficients of variation for repeatability and reproducibility in assessments of anti-Xa activity were 1.0% and 1.2%, respectively. The tolerance interval in reproducibility precision conditions, expressed as percentage potency, was 96.8-103.2% of the drug product target of 10,000 IU/ml, comparing favorably with the United States of America Pharmacopeia specification (90-110%). The maximum difference between assays in two different laboratories is expected to be 4.1%. The reproducibility characteristics of anti-IIa activity assessments were found to be similar. These results demonstrate the effectiveness of the standardization process established and allow for further improvements to quality control in Lovenox manufacture. This process guarantees closeness between actual and target potencies, as exemplified by the results of release assays obtained during a three-year period. Copyright © 2013 Elsevier B.V. All rights reserved.

UV cross-linking of donor corneas confers resistance to keratolysis.

PubMed

Arafat, Samer N; Robert, Marie-Claude; Shukla, Anita N; Dohlman, Claes H; Chodosh, James; Ciolino, Joseph B

2014-09-01

The aim of this study was to develop a modified ex vivo corneal cross-linking method that increases stromal resistance to enzymatic degradation for use as a carrier for the Boston keratoprosthesis. Ex vivo cross-linking of human corneas was performed using Barron artificial anterior chambers. The corneas were deepithelialized, pretreated with riboflavin solution (0.1% riboflavin/20% dextran), and irradiated with ultraviolet A (UV-A) light (λ = 370 nm, irradiance = 3 mW/cm) for various durations. The combined effect of UV-A and gamma (γ) irradiation was also assessed using the commercially available γ-irradiated corneal donors. The corneas were then trephined and incubated at 37°C with 0.3% collagenase A solution. The time to dissolution of each cornea was compared across treatments. Deepithelialized corneas (no UV light, no riboflavin) dissolved in 5.8 ± 0.6 hours. Cross-linked corneas demonstrated increased resistance to dissolution, with a time to dissolution of 17.8 ± 2.6 hours (P < 0.0001). The corneal tissues' resistance to collagenase increased with longer UV-A exposure, reaching a plateau at 30 minutes. Cross-linking both the anterior and posterior corneas did not provide added resistance when compared with cross-linking the anterior corneas only (P > 0.05). γ-irradiated corneas dissolved as readily as deepithelialized controls regardless of whether they were further cross-linked (5.6 ± 1.2 hours) or not (6.1 ± 0.6 hours) (P = 0.43). Collagen cross-linking of the deepithelialized anterior corneal surface for 30 minutes conferred optimal resistance to in vitro keratolysis by collagenase A.

Genome-wide identification of QTLs conferring high-temperature adult-plant (HTAP) resistance to stripe rust (Puccinia striiformis f. sp. tritici) in wheat

USDA-ARS?s Scientific Manuscript database

High-temperature adult-plant (HTAP) resistance to stripe rust (caused by Puccinia striiformis f. sp. tritici) is a durable type of resistance in wheat. The objective of this study was to identify quantitative trait loci (QTL) conferring HTAP resistance to stripe rust in a population consisting of 16...

Acoustic Emission Monitoring of the DC-XA Composite Liquid Hydrogen Tank During Structural Testing

NASA Technical Reports Server (NTRS)

Wilkerson, C.

1996-01-01

The results of acoustic emission (AE) monitoring of the DC-XA composite liquid hydrogen tank are presented in this report. The tank was subjected to pressurization, tensile, and compressive loads at ambient temperatures and also while full of liquid nitrogen. The tank was also pressurized with liquid hydrogen. AE was used to monitor the tank for signs of structural defects developing during the test.

Drug resistance conferred by mutations outside the active site through alterations in the dynamic and structural ensemble of HIV-1 protease.

PubMed

Ragland, Debra A; Nalivaika, Ellen A; Nalam, Madhavi N L; Prachanronarong, Kristina L; Cao, Hong; Bandaranayake, Rajintha M; Cai, Yufeng; Kurt-Yilmaz, Nese; Schiffer, Celia A

2014-08-27

HIV-1 protease inhibitors are part of the highly active antiretroviral therapy effectively used in the treatment of HIV infection and AIDS. Darunavir (DRV) is the most potent of these inhibitors, soliciting drug resistance only when a complex combination of mutations occur both inside and outside the protease active site. With few exceptions, the role of mutations outside the active site in conferring resistance remains largely elusive. Through a series of DRV-protease complex crystal structures, inhibition assays, and molecular dynamics simulations, we find that single and double site mutations outside the active site often associated with DRV resistance alter the structure and dynamic ensemble of HIV-1 protease active site. These alterations correlate with the observed inhibitor binding affinities for the mutants, and suggest a network hypothesis on how the effect of distal mutations are propagated to pivotal residues at the active site and may contribute to conferring drug resistance.

Targeted sequencing identifies genetic alterations that confer primary resistance to EGFR tyrosine kinase inhibitor (Korean Lung Cancer Consortium).

PubMed

Lim, Sun Min; Kim, Hye Ryun; Cho, Eun Kyung; Min, Young Joo; Ahn, Jin Seok; Ahn, Myung-Ju; Park, Keunchil; Cho, Byoung Chul; Lee, Ji-Hyun; Jeong, Hye Cheol; Kim, Eun Kyung; Kim, Joo-Hang

2016-06-14

Non-small-cell lung cancer (NSCLC) patients with activating epidermal growth factor receptor (EGFR) mutations may exhibit primary resistance to EGFR tyrosine kinase inhibitor (TKI). We aimed to examine genomic alterations associated with de novo resistance to gefitinib in a prospective study of NSCLC patients. One-hundred and fifty two patients with activating EGFR mutations were included in this study and 136 patients' tumor sample were available for targeted sequencing of genomic alterations in 22 genes using the Colon and Lung Cancer panel (Ampliseq, Life Technologies). All 132 patients with EGFR mutation were treated with gefitinib for their treatment of advanced NSCLC. Twenty patients showed primary resistance to EGFR TKI, and were classified as non-responders. A total of 543 somatic single-nucleotide variants (498 missense, 13 nonsense) and 32 frameshift insertions/deletions, with a median of 3 mutations per sample. TP53 was most commonly mutated (47%) and mutations in SMAD4 was also common (19%), as well as DDR2 (16%), PIK3CA (15%), STK11 (14%), and BRAF (7%). Genomic mutations in the PI3K/Akt/mTOR pathway were commonly found in non-responders (45%) compared to responders (27%), and they had significantly shorter progression-free survival and overall survival compared to patients without mutations (2.1 vs. 12.8 months, P=0.04, 15.7 vs. not reached, P<0.001). FGFR 1-3 alterations, KRAS mutations and TP53 mutations were more commonly detected in non-responders compared to responders. Genomic mutations in the PI3K/Akt/mTOR pathway were commonly identified in non-responders and may confer resistance to EGFR TKI. Screening lung adenocarcinoma patients with clinical cancer gene test may aid in selecting out those who show primary resistance to EGFR TKI (NCT01697163).

Mapping of chloroplast mutations conferring resistance to antibiotics in Chlamydomonas: evidence for a novel site of streptomycin resistance in the small subunit rRNA.

PubMed

Gauthier, A; Turmel, M; Lemieux, C

1988-10-01

A major obstacle to our understanding of the mechanisms governing the inheritance, recombination and segregation of chloroplast genes in Chlamydomonas is that the majority of antibiotic resistance mutations that have been used to gain insights into such mechanisms have not been physically localized on the chloroplast genome. We report here the physical mapping of two chloroplast antibiotic resistance mutations: one conferring cross-resistance to erythromycin and spiramycin in Chlamydomonas moewusii (er-nM1) and the other conferring resistance to streptomycin in the interfertile species C. eugametos (sr-2). The er-nM1 mutation results from a C to G transversion at a well-known site of macrolide resistance within the peptidyl transferase loop region of the large subunit rRNA gene. This locus, designated rib-2 in yeast mitochondrial DNA, corresponds to residue C-2611 in the 23 S rRNA of Escherichia coli. The sr-2 locus maps within the small subunit (SSU) rRNA gene at a site that has not been described previously. The mutation results from an A to C transversion at a position equivalent to residue A-523 in the E. coli 16 S rRNA. Although this region of the E. coli SSU rRNA has no binding affinity for streptomycin, it binds to ribosomal protein S4, a protein that has long been associated with the response of bacterial cells to this antibiotic. We propose that the sr-2 mutation indirectly affects the nearest streptomycin binding site through an altered interaction between a ribosomal protein and the SSU rRNA.

Identification of QTLs conferring resistance to downy mildews of maize in Asia.

PubMed

George, M L C; Prasanna, B M; Rathore, R S; Setty, T A S; Kasim, F; Azrai, M; Vasal, S; Balla, O; Hautea, D; Canama, A; Regalado, E; Vargas, M; Khairallah, M; Jeffers, D; Hoisington, D

2003-08-01

Downy mildew is one of the most destructive diseases of maize in subtropical and tropical regions in Asia. As a prerequisite for improving downy mildew resistance in maize, we analyzed quantitative trait loci (QTLs) involved in resistance to the important downy mildew pathogens--Peronosclerospora sorghi (sorghum downy mildew) and P. heteropogoni (Rajasthan downy mildew) in India, P. maydis (Java downy mildew) in Indonesia, P. zeae in Thailand and P. philippinensis in the Philippines--using a recombinant inbred line population derived from a cross between Ki3 (downy mildew resistant) and CML139 (susceptible). Resistance was evaluated as percentage disease incidence in replicated field trials at five downy mildew 'hotspots' in the four countries. Heritability estimates of individual environments ranged from 0.58 to 0.75 with an across environment heritability of 0.50. Composite interval mapping was applied for QTL detection using a previously constructed restriction fragment length polymorphism linkage map. The investigation resulted in the identification of six genomic regions on chromosomes 1, 2, 6, 7 and 10 involved in the resistance to the downy mildews under study, explaining, in total, 26-57% of the phenotypic variance for disease response. Most QTL alleles conferring resistance to the downy mildews were from Ki3. All QTLs showed significant QTL x environment interactions, suggesting that the expression of the QTL may be environment-dependent. A strong QTL on chromosome 6 was stable across environments, significantly affecting disease resistance at the five locations in four Asian countries. Simple-sequence repeat markers tightly linked to this QTL were identified for potential use in marker-assisted selection.

The Ablation of Mitochondrial Protein Phosphatase Pgam5 Confers Resistance Against Metabolic Stress.

PubMed

Sekine, Shiori; Yao, Akari; Hattori, Kazuki; Sugawara, Sho; Naguro, Isao; Koike, Masato; Uchiyama, Yasuo; Takeda, Kohsuke; Ichijo, Hidenori

2016-03-01

Phosphoglycerate mutase family member 5 (PGAM5) is a mitochondrial protein phosphatase that has been reported to be involved in various stress responses from mitochondrial quality control to cell death. However, its roles in vivo are largely unknown. Here, we show that Pgam5-deficient mice are resistant to several metabolic insults. Under cold stress combined with fasting, Pgam5-deficient mice better maintained body temperature than wild-type mice and showed an extended survival rate. Serum triglycerides and lipid content in brown adipose tissue (BAT), a center of adaptive thermogenesis, were severely reduced in Pgam5-deficient mice. Moreover, although Pgam5 deficiency failed to maintain proper mitochondrial integrity in BAT, it reciprocally resulted in the dramatic induction of fibroblast growth factor 21 (FGF21) that activates various functions of BAT including thermogenesis. Thus, the enhancement of lipid metabolism and FGF21 may contribute to the cold resistance of Pgam5-deficient mice under fasting condition. Finally, we also found that Pgam5-deficient mice are resistant to high-fat-diet-induced obesity. Our study uncovered that PGAM5 is involved in the whole-body metabolism in response to stresses that impose metabolic challenges on mitochondria.

Identification of a rice gene (Bph 1) conferring resistance to brown planthopper (Nilaparvata lugens Stal) using STS markers.

PubMed

Kim, Suk-Man; Sohn, Jae-Keun

2005-08-31

This study was carried out to identify a high-resolution marker for a gene conferring resistance to brown planthopper (BPH) biotype 1, using japonica type resistant lines. Bulked segregant analyses were conducted using 520 RAPD primers to identify RAPD fragments linked to the BPH resistance gene. Eleven RAPDs were shown to be polymorphic amplicons between resistant and susceptible progeny. One of these primers, OPE 18, which amplified a 923 bp band tightly linked to resistance, was converted into a sequence-tagged-site (STS) marker. The STS marker, BpE18-3, was easily detectable as a dominant band with tight linkage (3.9cM) to Bph1. It promises to be useful as a marker for assisted selection of resistant progeny in backcross breeding programs to introgress the resistance gene into elite japonica cultivars.

76 FR 67725 - Technical Conference on Penalty Guidelines; Second Notice of Technical Conference on Penalty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-02

... Conference on Penalty Guidelines; Second Notice of Technical Conference on Penalty Guidelines On September 21... Conference on Penalty Guidelines to be held on November 17, 2011. The conference will be held from 1 p.m. to... impact of the Penalty Guidelines, which the Commission issued on September 17, 2010,\\1\\ on compliance and...

A ΩXaV motif in the Rift Valley fever virus NSs protein is essential for degrading p62, forming nuclear filaments and virulence

PubMed Central

Cyr, Normand; de la Fuente, Cynthia; Lecoq, Lauriane; Guendel, Irene; Chabot, Philippe R.; Kehn-Hall, Kylene; Omichinski, James G.

2015-01-01

Rift Valley fever virus (RVFV) is a single-stranded RNA virus capable of inducing fatal hemorrhagic fever in humans. A key component of RVFV virulence is its ability to form nuclear filaments through interactions between the viral nonstructural protein NSs and the host general transcription factor TFIIH. Here, we identify an interaction between a ΩXaV motif in NSs and the p62 subunit of TFIIH. This motif in NSs is similar to ΩXaV motifs found in nucleotide excision repair (NER) factors and transcription factors known to interact with p62. Structural and biophysical studies demonstrate that NSs binds to p62 in a similar manner as these other factors. Functional studies in RVFV-infected cells show that the ΩXaV motif is required for both nuclear filament formation and degradation of p62. Consistent with the fact that the RVFV can be distinguished from other Bunyaviridae-family viruses due to its ability to form nuclear filaments in infected cells, the motif is absent in the NSs proteins of other Bunyaviridae-family viruses. Taken together, our studies demonstrate that p62 binding to NSs through the ΩXaV motif is essential for degrading p62, forming nuclear filaments and enhancing RVFV virulence. In addition, these results show how the RVFV incorporates a simple motif into the NSs protein that enables it to functionally mimic host cell proteins that bind the p62 subunit of TFIIH. PMID:25918396

A ΩXaV motif in the Rift Valley fever virus NSs protein is essential for degrading p62, forming nuclear filaments and virulence.

PubMed

Cyr, Normand; de la Fuente, Cynthia; Lecoq, Lauriane; Guendel, Irene; Chabot, Philippe R; Kehn-Hall, Kylene; Omichinski, James G

2015-05-12

Rift Valley fever virus (RVFV) is a single-stranded RNA virus capable of inducing fatal hemorrhagic fever in humans. A key component of RVFV virulence is its ability to form nuclear filaments through interactions between the viral nonstructural protein NSs and the host general transcription factor TFIIH. Here, we identify an interaction between a ΩXaV motif in NSs and the p62 subunit of TFIIH. This motif in NSs is similar to ΩXaV motifs found in nucleotide excision repair (NER) factors and transcription factors known to interact with p62. Structural and biophysical studies demonstrate that NSs binds to p62 in a similar manner as these other factors. Functional studies in RVFV-infected cells show that the ΩXaV motif is required for both nuclear filament formation and degradation of p62. Consistent with the fact that the RVFV can be distinguished from other Bunyaviridae-family viruses due to its ability to form nuclear filaments in infected cells, the motif is absent in the NSs proteins of other Bunyaviridae-family viruses. Taken together, our studies demonstrate that p62 binding to NSs through the ΩXaV motif is essential for degrading p62, forming nuclear filaments and enhancing RVFV virulence. In addition, these results show how the RVFV incorporates a simple motif into the NSs protein that enables it to functionally mimic host cell proteins that bind the p62 subunit of TFIIH.

Anticoagulation beyond direct thrombin and factor Xa inhibitors: indications for targeting the intrinsic pathway?

PubMed

van Montfoort, Maurits L; Meijers, Joost C M

2013-08-01

Antithrombotic drugs like vitamin K antagonists and heparin have been the gold standard for the treatment and prevention of thromboembolic disease for many years. Unfortunately, there are several disadvantages of these antithrombotic drugs: they are accompanied by serious bleeding problems, it is necessary to monitor the therapeutic window, and there are various interactions with food and other drugs. This has led to the development of new oral anticoagulants, specifically inhibiting either thrombin or factor Xa. In terms of effectiveness, these drugs are comparable to the currently available anticoagulants; however, they are still associated with issues such as bleeding, reversal of the drug and complicated laboratory monitoring. Vitamin K antagonists, heparin, direct thrombin and factor Xa inhibitors have in common that they target key proteins of the haemostatic system. In an attempt to overcome these difficulties we investigated whether the intrinsic coagulation factors (VIII, IX, XI, XII, prekallikrein and high-molecular-weight kininogen) are superior targets for anticoagulation. We analysed epidemiological data concerning thrombosis and bleeding in patients deficient in one of the intrinsic pathway proteins. Furthermore, we discuss several thrombotic models in intrinsic coagulation factor-deficient animals. The combined results suggest that intrinsic coagulation factors could be suitable targets for anticoagulant drugs.

Educational Accountability in the 21st Century. 2000 CRESST Conference Proceedings (Los Angeles, California, September 14-15, 2000). CSE Technical Report 549.

ERIC Educational Resources Information Center

Lewis, Anne

This report outlines the major themes of the 2000 annual conference of the Center for Research on Evaluation, Standards, and Student Testing (CRESST), which focused on educational accountability in the 21st century. The conference opened with a panel presentation on the Texas accountability system. This session included a presentation by one of…

Rivaroxaban Levels in Patients' Plasmas are Comparable by Using Two Different Anti Xa Assay/Coagulometer Systems Calibrated with Two Different Calibrators.

PubMed

Martinuzzo, Marta E; Duboscq, Cristina; Lopez, Marina S; Barrera, Luis H; Vinuales, Estela S; Ceresetto, Jose; Forastiero, Ricardo R; Oyhamburu, Jose

2018-06-01

Rivaroxaban oral anticoagulant does not need laboratory monitoring, but in some situations plasma level measurement is useful. The objective of this paper was to verify analytical performance and compare two rivaroxaban calibrated anti Xa assays/coagulometer systems with specific or other branch calibrators. In 59 samples drawn at trough or peak from patients taking rivaroxaban, plasma levels were measured by HemosIL Liquid anti Xa in ACLTOP 300/500, and STA liquid Anti Xa in TCoag Destiny Plus. HemosIL and STA rivaroxaban calibrators and controls were used. CLSI guideline procedures EP15A3 for precision and trueness, EP6 for linearity, and EP9 for methods comparison were used. Coefficient of variation within run and total precision (CVR and CVWL respectively) of plasmatic rivaroxaban were < 4.2 and < 4.85% and BIAS < 7.4 and < 6.5%, for HemosIL-ACL TOP and STA-Destiny systems, respectively. Linearity verification 8 - 525 ng/mL a Deming regression for methods comparison presented R 0.963, 0.968 and 0.982, with a mean CV 13.3% when using different systems and calibrations. The analytical performance of plasma rivaroxaban was acceptable in both systems, and results from reagent/coagulometer systems are comparable even when calibrating with different branch material.

We Navigate Together into the Future. Selected Papers from the PIALA Conference 2016, Pacific Islands Association of Libraries, Archives, and Museums Annual Conference (26th, Colonia, Yap State, Federated States of Micronesia, November 21-26, 2016)

ERIC Educational Resources Information Center

Drake, Paul Burton, Ed.

2017-01-01

This publication follows the tradition of publishing selected papers from the Pacific Islands Association of Libraries, Archives and Museums (PIALA) annual conferences. This 26th annual conference was held in Colonia, Yap State, Federated States of Micronesia, November 21-26, 2016 and celebrated the Association's Twenty-Fifth anniversary. This…

XaNSoNS: GPU-accelerated simulator of diffraction patterns of nanoparticles

NASA Astrophysics Data System (ADS)

Neverov, V. S.

XaNSoNS is an open source software with GPU support, which simulates X-ray and neutron 1D (or 2D) diffraction patterns and pair-distribution functions (PDF) for amorphous or crystalline nanoparticles (up to ∼107 atoms) of heterogeneous structural content. Among the multiple parameters of the structure the user may specify atomic displacements, site occupancies, molecular displacements and molecular rotations. The software uses general equations nonspecific to crystalline structures to calculate the scattering intensity. It supports four major standards of parallel computing: MPI, OpenMP, Nvidia CUDA and OpenCL, enabling it to run on various architectures, from CPU-based HPCs to consumer-level GPUs.

An intragenic approach to confer glyphosate resistance in chile (Capsicum annuum) by introducing an in vitro mutagenized chile EPSPS gene encoding for a glyphosate resistant EPSPS protein

PubMed Central

Bagga, Suman; Apodaca, Kimberly; Lucero, Yvonne

2018-01-01

Chile pepper (Capsicum annuum) is an important high valued crop worldwide, and when grown on a large scale has problems with weeds. One important herbicide used is glyphosate. Glyphosate inactivates the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), a key enzyme in the synthesis of aromatic amino acids. A transgenic approach towards making glyphosate resistant plants, entails introducing copies of a gene encoding for glyphosate-resistant EPSPS enzyme into the plant. The main objective of our work was to use an intragenic approach to confer resistance to glyphosate in chile which would require using only chile genes for transformation including the selectable marker. Tobacco was used as the transgenic system to identify different gene constructs that would allow for the development of the intragenic system for chile, since chile transformation is inefficient. An EPSPS gene was isolated from chile and mutagenized to introduce substitutions that are known to make the encoded enzyme resistant to glyphosate. The promoter for EPSPS gene was isolated from chile and the mutagenized chile EPSPS cDNA was engineered behind both the CaMV35S promoter and the EPSPS promoter. The leaves from the transformants were checked for resistance to glyphosate using a cut leaf assay. In tobacco, though both gene constructs exhibited some degree of resistance to glyphosate, the construct with the CaMV35S promoter was more effective and as such chile was transformed with this gene construct. The chile transformants showed resistance to low concentrations of glyphosate. Furthermore, preliminary studies showed that the mutated EPSPS gene driven by the CaMV35S promoter could be used as a selectable marker for transformation. We have shown that an intragenic approach can be used to confer glyphosate-resistance in chile. However, we need a stronger chile promoter and a mutated chile gene that encodes for a more glyphosate resistant EPSPS protein. PMID:29649228

Teaching of Psychology: Ideas and Innovations. Proceedings of the Annual Conference on Undergraduate Teaching of Psychology (23rd, Tarrytown, New York, March 20-21, 2009)

ERIC Educational Resources Information Center

Howell-Carter, Marya, Ed.; Gonder, Jennifer, Ed.

2009-01-01

The document is a summary of the conference proceedings for the 23rd Annual Farmingdale State College Teaching of Psychology Conference held on March 20-21, 2009 at the DoubleTree Hotel in Tarrytown, New York. The conference featured a keynote address by Dr. Jeffrey Nevid on Reaching and teaching the millennials: Helping today's students become…

Teaching of Psychology: Ideas and Innovations. Proceedings of the Annual Conference on Undergraduate Teaching of Psychology (21st, Kerhonkson, New York, March 28-30, 2007)

ERIC Educational Resources Information Center

Zaromatidis, Katherine, Ed.; Oswald, Patricia A., Ed.; Levine, Judith R., Ed.; Indenbaum, Gene, Ed.

2007-01-01

The 21st Annual Conference on Undergraduate Teaching of Psychology was held on March 28-30, 2007 at Hudson Valley Resort and Day Spa in Kerhonkson, New York. The conference was sponsored by the Psychology Department of Farmingdale State College. The conference included twenty five presentations and ten of these are included in these proceedings.…

Silencing of copine genes confers common wheat enhanced resistance to powdery mildew.

PubMed

Zou, Baohong; Ding, Yuan; Liu, He; Hua, Jian

2018-06-01

Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is a major threat to the production of wheat (Triticum aestivum). It is of great importance to identify new resistance genes for the generation of Bgt-resistant or Bgt-tolerant wheat varieties. Here, we show that the wheat copine genes TaBON1 and TaBON3 negatively regulate wheat disease resistance to Bgt. Two copies of TaBON1 and three copies of TaBON3, located on chromosomes 6AS, 6BL, 1AL, 1BL and 1DL, respectively, were identified from the current common wheat genome sequences. The expression of TaBON1 and TaBON3 is responsive to both pathogen infection and temperature changes. Knocking down of TaBON1 or TaBON3 by virus-induced gene silencing (VIGS) induces the up-regulation of defence responses in wheat. These TaBON1- or TaBON3-silenced plants exhibit enhanced wheat disease resistance to Bgt, accompanied by greater accumulation of hydrogen peroxide and heightened cell death. In addition, high temperature has little effect on the up-regulation of defence response genes conferred by the silencing of TaBON1 or TaBON3. Our study shows a conserved function of plant copine genes in plant immunity and provides new genetic resources for the improvement of resistance to powdery mildew in wheat. © 2017 BSPP AND JOHN WILEY & SONS LTD.

Mapping genes for resistance to stripe rust in spring wheat landrace PI 480035

PubMed Central

Krishnan, Vandhana; Jiwan, Derick; Chen, Xianming; Skinner, Daniel Z.; See, Deven R.

2017-01-01

Stripe rust caused by Puccinia striiformis Westend. f. sp. tritici Erikks. is an economically important disease of wheat (Triticum aestivum L.). Hexaploid spring wheat landrace PI 480035 was highly resistant to stripe rust in the field in Washington during 2011 and 2012. The objective of this research was to identify quantitative trait loci (QTL) for stripe rust resistance in PI 480035. A spring wheat, “Avocet Susceptible” (AvS), was crossed with PI 480035 to develop a biparental population of 110 recombinant inbred lines (RIL). The population was evaluated in the field in 2013 and 2014 and seedling reactions were examined against three races (PSTv-14, PSTv-37, and PSTv-40) of the pathogen under controlled conditions. The population was genotyped with genotyping-by-sequencing and microsatellite markers across the whole wheat genome. A major QTL, QYr.wrsggl1-1BS was identified on chromosome 1B. The closest flanking markers were Xgwm273, Xgwm11, and Xbarc187 1.01 cM distal to QYr.wrsggl1-1BS, Xcfd59 0.59 cM proximal and XA365 3.19 cM proximal to QYr.wrsggl1-1BS. Another QTL, QYr.wrsggl1-3B, was identified on 3B, which was significant only for PSTv-40 and was not significant in the field, indicating it confers a race-specific resistance. Comparison with markers associated with previously reported Yr genes on 1B (Yr64, Yr65, and YrH52) indicated that QYr.wrsggl1-1BS is potentially a novel stripe rust resistance gene that can be incorporated into modern breeding materials, along with other all-stage and adult-plant resistance genes to develop cultivars that can provide durable resistance. PMID:28542451

Identification and characterization of Sr13, a tetraploid wheat gene that confers resistance to the Ug99 stem rust race group

USDA-ARS?s Scientific Manuscript database

The Puccinia graminis f. sp. tritici (Pgt) Ug99 race group is virulent to most stem rust resistance genes currently deployed in wheat and poses a serious threat to global wheat production. The durum wheat (Triticum turgidum ssp. durum) gene Sr13 confers resistance to Ug99 in addition to virulent rac...

Overexpression of Salmonella enterica serovar Typhi recA gene confers fluoroquinolone resistance in Escherichia coli DH5α.

PubMed

Yassien, M A M; Elfaky, M A

2015-11-01

A spontaneous fluoroquinolone-resistant mutant (STM1) was isolated from its parent Salmonella enterica serovar Typhi (S. Typhi) clinical isolate. Unlike its parent isolate, this mutant has selective resistance to fluoroquinolones without any change in its sensitivity to various other antibiotics. DNA gyrase assays revealed that the fluoroquinolone resistance phenotype of the STM1 mutant did not result from alteration of the fluoroquinolone sensitivity of the DNA gyrase isolated from it. To study the mechanism of fluoroquinolone resistance, a genomic library from the STM1 mutant was constructed in Escherichia coli DH5α and two recombinant plasmids were obtained. Only one of these plasmids (STM1-A) conferred the selective fluoroquinolone resistance phenotype to E. coli DH5α. The chromosomal insert from STM1-A, digested with EcoRI and HindIII restriction endonucleases, produced two DNA fragments and these were cloned separately into pUC19 thereby generating two new plasmids, STM1-A1 and STM1-A2. Only STM1-A1 conferred the selective fluoroquinolone resistance phenotype to E. coli DH5α. Sequence and subcloning analyses of STM1-A1 showed the presence of an intact RecA open reading frame. Unlike that of the wild-type E. coli DH5α, protein analysis of a crude STM1-A1 extract showed overexpression of a 40 kDa protein. Western blotting confirmed the 40 kDa protein band to be RecA. When a RecA PCR product was cloned into pGEM-T and introduced into E. coli DH5α, the STM1-A11 subclone retained fluoroquinolone resistance. These results suggest that overexpression of RecA causes selective fluoroquinolone resistance in E. coli DH5α.

Expression of the Bs2 pepper gene confers resistance to bacterial spot disease in tomato

PubMed Central

Tai, Thomas H.; Dahlbeck, Douglas; Clark, Eszter T.; Gajiwala, Paresh; Pasion, Romela; Whalen, Maureen C.; Stall, Robert E.; Staskawicz, Brian J.

1999-01-01

The Bs2 resistance gene of pepper specifically recognizes and confers resistance to strains of Xanthomonas campestris pv. vesicatoria that contain the corresponding bacterial avirulence gene, avrBs2. The involvement of avrBs2 in pathogen fitness and its prevalence in many X. campestris pathovars suggests that the Bs2 gene may be durable in the field and provide resistance when introduced into other plant species. Employing a positional cloning strategy, the Bs2 locus was isolated and the gene was identified by coexpression with avrBs2 in an Agrobacterium-mediated transient assay. A single candidate gene, predicted to encode motifs characteristic of the nucleotide binding site–leucine-rich repeat class of resistance genes, was identified. This gene specifically controlled the hypersensitive response when transiently expressed in susceptible pepper and tomato lines and in a nonhost species, Nicotiana benthamiana, and was designated as Bs2. Functional expression of Bs2 in stable transgenic tomatoes supports its use as a source of resistance in other Solanaceous plant species. PMID:10570214

Expression of the Bs2 pepper gene confers resistance to bacterial spot disease in tomato.

PubMed

Tai, T H; Dahlbeck, D; Clark, E T; Gajiwala, P; Pasion, R; Whalen, M C; Stall, R E; Staskawicz, B J

1999-11-23

The Bs2 resistance gene of pepper specifically recognizes and confers resistance to strains of Xanthomonas campestris pv. vesicatoria that contain the corresponding bacterial avirulence gene, avrBs2. The involvement of avrBs2 in pathogen fitness and its prevalence in many X. campestris pathovars suggests that the Bs2 gene may be durable in the field and provide resistance when introduced into other plant species. Employing a positional cloning strategy, the Bs2 locus was isolated and the gene was identified by coexpression with avrBs2 in an Agrobacterium-mediated transient assay. A single candidate gene, predicted to encode motifs characteristic of the nucleotide binding site-leucine-rich repeat class of resistance genes, was identified. This gene specifically controlled the hypersensitive response when transiently expressed in susceptible pepper and tomato lines and in a nonhost species, Nicotiana benthamiana, and was designated as Bs2. Functional expression of Bs2 in stable transgenic tomatoes supports its use as a source of resistance in other Solanaceous plant species.

Human plasma kallikrein and tissue kallikrein binding to a substrate based on the reactive site of a factor Xa inhibitor isolated from Bauhinia ungulata seeds.

PubMed

Oliva, M L; Andrade, S A; Batista, I F; Sampaio, M U; Juliano, M; Fritz, H; Auerswald, E A; Sampaio, C A

1999-12-01

Kunitz type Bauhinia ungulata factor Xa inhibitor (BuXI) was purified from B. ungulata seeds. BuXI inactivates factor Xa and human plasma kallikrein (HuPK) with Ki values of 18.4 and 6.9 nM, respectively. However, Bauhinia variegata trypsin inhibitor (BvTI) which is 70% homologous to BuXI does not inhibit factor Xa and is less efficient on HuPK (Ki = 80 nM). The comparison between BuXI and BvTI reactive site structure indicates differences at Met59, Thr66 and Met67 residues. The hydrolysis rate of quenched fluorescence peptide substrates based on BuXI reactive site sequence, Abz-VMIAALPRTMFIQ-EDDnp (leading peptide), by HuPK and porcine pancreatic kallikrein (PoPK) is low, but hydrolysis is enhanced with Abz-VMIAALPRTMQ-EDDnp, derived from the leading peptide shortened by removing the dipeptide Phe-Ileu from the C-terminal portion, for HuPK (Km = 0.68 microM, k(cat)/Km = 1.3 x 10(6) M(-1) s(-1)), and the shorter substrate Abz-LPRTMQ-EDDnp is better for PoPK (Km = 0.66 microM, k(cat)/Km = 2.2 x 10(3) M(-1) s(-1)). The contribution of substrate methionine residues to HuPK and PoPK hydrolysis differs from that observed with factor Xa. The determined Km and k(cat) values suggest that the substrates interact with kallikreins the same as an enzyme and inhibitor interacts to form complexes.

Introgression and pyramiding into common bean market class fabada of genes conferring resistance to anthracnose and potyvirus.

PubMed

Ferreira, Juan José; Campa, Ana; Pérez-Vega, Elena; Rodríguez-Suárez, Cristina; Giraldez, Ramón

2012-03-01

Anthracnose and bean common mosaic (BCM) are considered major diseases in common bean crop causing severe yield losses worldwide. This work describes the introgression and pyramiding of genes conferring genetic resistance to BCM and anthracnose local races into line A25, a bean genotype classified as market class fabada. Resistant plants were selected using resistance tests or combining resistance tests and marker-assisted selection. Lines A252, A321, A493, Sanilac BC6-Are, and BRB130 were used as resistance sources. Resistance genes to anthracnose (Co-2 ( C ), Co-2 ( A252 ) and Co-3/9) and/or BCM (I and bc-3) were introgressed in line A25 through six parallel backcrossing programs, and six breeding lines showing a fabada seed phenotype were obtained after six backcross generations: line A1258 from A252; A1231 from A321; A1220 from A493; A1183 and A1878 from Sanilac BC6-Are; and line A2418 from BRB130. Pyramiding of different genes were developed using the pedigree method from a single cross between lines obtained in the introgression step: line A1699 (derived from cross A1258 × A1220), A2438 (A1220 × A1183), A2806 (A1878 × A2418), and A3308 (A1699 × A2806). A characterization based on eight morpho-agronomic traits revealed a limited differentiation among the obtained breeding lines and the recurrent line A25. However, using a set of seven molecular markers linked to the loci used in the breeding programs it was possible to differentiate the 11 fabada lines. Considering the genetic control of the resistance in resistant donor lines, the observed segregations in the last backcrossing generation, the reaction against the pathogens, and the expression of the molecular markers it was also possible to infer the genotype conferring resistance in the ten fabada breeding lines obtained. As a result of these breeding programs, genetic resistance to three anthracnose races controlled by genes included in clusters Co-2 and Co-3/9, and genetic resistance to BCM controlled

The germin-like protein OsGLP2-1 enhances resistance to fungal blast and bacterial blight in rice.

PubMed

Liu, Qing; Yang, Jianyuan; Yan, Shijuan; Zhang, Shaohong; Zhao, Junliang; Wang, Wenjuan; Yang, Tifeng; Wang, Xiaofei; Mao, Xingxue; Dong, Jingfang; Zhu, Xiaoyuan; Liu, Bin

2016-11-01

This is the first report that GLP gene (OsGLP2-1) is involved in panicle blast and bacterial blight resistance in rice. In addition to its resistance to blast and bacterial blight, OsGLP2-1 has also been reported to co-localize with a QTLs for sheath blight resistance in rice. These suggest that the disease resistance provided by OsGLP2-1 is quantitative and broad spectrum. Its good resistance to these major diseases in rice makes it to be a promising target in rice breeding. Rice (Oryza sativa) blast caused by Magnaporthe oryzae and bacterial blight caused by Xanthomonas oryzae pv. oryzae are the two most destructive rice diseases worldwide. Germin-like protein (GLP) gene family is one of the important defense gene families which have been reported to be involved in disease resistance in plants. Although GLP proteins have been demonstrated to positively regulate leaf blast resistance in rice, their involvement in resistance to panicle blast and bacterial blight, has not been reported. In this study, we reported that one of the rice GLP genes, OsGLP2-1, was significantly induced by blast fungus. Overexpression of OsGLP2-1 quantitatively enhanced resistance to leaf blast, panicle blast and bacterial blight. The temporal and spatial expression analysis revealed that OsGLP2-1is highly expressed in leaves and panicles and sub-localized in the cell wall. Compared with empty vector transformed (control) plants, the OsGLP2-1 overexpressing plants exhibited higher levels of H 2 O 2 both before and after pathogen inoculation. Moreover, OsGLP2-1 was significantly induced by jasmonic acid (JA). Overexpression of OsGLP2-1 induced three well-characterized defense-related genes which are associated in JA-dependent pathway after pathogen infection. Higher endogenous level of JA was also identified in OsGLP2-1 overexpressing plants than in control plants both before and after pathogen inoculation. Together, these results suggest that OsGLP2-1 functions as a positive regulator to

Silencing of miR156 confers enhanced resistance to brown planthopper in rice.

PubMed

Ge, Yafei; Han, Junyou; Zhou, Guoxin; Xu, Yunmin; Ding, Yue; Shi, Min; Guo, Changkui; Wu, Gang

2018-06-22

Silencing of miR156 in rice confers enhanced resistance to brown planthopper through reducing JA and JA-Ile biosynthesis. Rice brown planthopper (BPH, Nilaparvata lugens Stål) threatens the sustainability of rice production and global food security. Due to the rapid adaptation of BPH to current germplasms in rice, development of novel types of resistant germplasms becomes increasingly important. Plant ontogenetic defense against pathogen and herbivores offers a broad spectrum and durable resistance, and has been experimentally tested in many plants; however, the underlying molecular mechanism remains unclear. miR156 is the master regulator of ontogeny in plants; modulation of miR156 is, therefore, expected to cause corresponding changes in BPH resistance. To test this hypothesis, we silenced miR156 using a target mimicry method in rice, and analyzed the resistance of miR156-silenced plants (MIM156) to BPH. MIM156 plants exhibited enhanced resistance to BPH based on analyses of honeydew excretion, nymph survival, fecundity of BPH, and the survival ratio of rice plants after BPH infestation. Molecular analysis indicated that the expression of MPK3, MPK6, and WRKY70, three genes involved in BPH resistance and jasmonic acid (JA) signaling, was altered in MIM156 plants. The JA and bioactive jasmonoyl-isoleucine levels and the expression of genes involved in JA biosynthesis were significantly reduced in MIM156 plants. Restoration of JA level by exogenous application increased the number of BPH feeding on MIM156 plants and reduced its resistance to BPH. Our findings suggest that miR156 negatively regulates BPH resistance by increasing JA level in rice; therefore, modulation of miR156-SPLs' pathway may offer a promising way to breed rice varieties with enhanced resistance against BPH and elite agronomically important traits.

Antibacterial activity of 4,5-dihydroxy-2-cyclopentan-1-one (DHCP) and cloning of a gene conferring DHCP resistance in Escherichia coli.

PubMed

Phadtare, S; Yamanaka, K; Kato, I; Inouye, M

2001-07-01

In the present study we report that 4,5-dihydroxy-2-cyclopentan-1-one (DHCP), which is derived from heat-treatment of uronic acid or its derivatives, has antibacterial activity against Escherichia coli. The compound causes complete growth inhibition at 350 microM concentration. We have cloned a gene from E. coli, which confers DHCP resistance when present in multicopy. The putative protein encoded by this gene (dep- DHCP efflux protein) is a transmembrane efflux protein with a high homology to other antibiotic-efflux proteins including those for chloramphenicol, bicyclomycin and tetracycline. However, the Dep protein does not confer cross-resistance to any of the antibiotics tested.

Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death

PubMed Central

Narayanan, Kannan Badri; Ali, Manaf; Barclay, Barry J.; Cheng, Qiang (Shawn); D’Abronzo, Leandro; Dornetshuber-Fleiss, Rita; Ghosh, Paramita M.; Gonzalez Guzman, Michael J.; Lee, Tae-Jin; Leung, Po Sing; Li, Lin; Luanpitpong, Suidjit; Ratovitski, Edward; Rojanasakul, Yon; Romano, Maria Fiammetta; Romano, Simona; Sinha, Ranjeet K.; Yedjou, Clement; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G.; Ryan, Elizabeth P.; Colacci, Anna Maria; Hamid, Roslida A.; Mondello, Chiara; Raju, Jayadev; Salem, Hosni K.; Woodrick, Jordan; Scovassi, A.Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Kim, Seo Yun; Bisson, William H.; Lowe, Leroy; Park, Hyun Ho

2015-01-01

Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis. PMID:26106145

Loss of cAMP/CRP regulation confers extreme high hydrostatic pressure resistance in Escherichia coli O157:H7.

PubMed

Vanlint, Dietrich; Pype, Brecht J Y; Rutten, Nele; Vanoirbeek, Kristof G A; Michiels, Chris W; Aertsen, Abram

2013-08-16

Application of high hydrostatic pressure (HHP) constitutes a valuable non-thermal pasteurization process in modern food conservation. Triggered by our interest in the rapid adaptive evolution towards HHP resistance in the food-borne pathogen E. coli O157:H7 (strain ATCC 43888) that was demonstrated earlier, we used genetic screening to identify specific loci in which a loss-of-function mutation would be sufficient to markedly increase HHP survival. As such, individual loss of RssB (anti RpoS-factor), CRP (catabolite response protein) and CyaA (adenylate cyclase) were each found to confer significant HHP resistance in the 300MPa range (i.e. >1,000-fold), and this phenotype invariably coincided with increased resistance against heat as well. In contrast to loss of RssB, however, loss of CRP or CyaA also conferred significantly increased resistance to 600MPa (i.e. >10,000-fold), suggesting cAMP/CRP homeostasis to affect extreme HHP resistance independently of increased RpoS activity. Surprisingly, none of the rapidly emerging HHP-resistant mutants of ATCC 43888 that were isolated previously did incur any mutations in rssB, crp or cyaA, indicating that a number of other loci can guide the rapid emergence of HHP resistance in E. coli O157:H7 as well. The inability of spontaneous rssB, crp or cyaA mutants to emerge during selective enrichment under HHP selection likely stems from their decreased competitive fitness during growth. Overall, this study is the first to shed light on the possible genetic strategies supporting the acquisition of HHP resistance in E. coli O157:H7. Copyright © 2013 Elsevier B.V. All rights reserved.

Daboxin P, a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity

PubMed Central

Iyer, Janaki Krishnamurthy; Shih, Norrapat; Majumder, Munmi; Mattaparthi, Venkata Satish Kumar; Mukhopadhyay, Rupak; Doley, Robin

2016-01-01

In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A2 activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca+2 binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A2 enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity. PMID:27089306

International conference on "Photosynthesis research for sustainability-2015" in honor of George C. Papageorgiou", September 21-26, 2015, Crete, Greece.

PubMed

Allakhverdiev, Suleyman I; Tomo, Tatsuya; Stamatakis, Kostas; Govindjee

2016-12-01

During September 21-26, 2015, an international conference entitled ''Photosynthesis Research for Sustainability-2015'' was held in honor of George C. Papageorgiou at the Conference Center of the Orthodox Academy of Crete, an exceptionally beautiful location right on the Mediterranean Sea coast, Kolymvari, Chania, Crete, (Greece) (see http://photosynthesis2015.cellreg.org/ ). The meeting was held under the auspices of the Greek "General Secretariat for Research and Technology" (GSRT). We first provide a brief introduction and key contributions of George C. Papageorgiou, the honored scientist, and then information on the conference, on the speakers, and the program. A special feature of this conference was awards given to 13 young investigators, who are recognized in this Report. Several photographs are also included; they show the pleasant ambience at this conference. We invite the readers to the next conference on "Photosynthesis Research for Sustainability-2016," which will honor Nathan Nelson and T. Nejat Veziroglu; it will be held during June 19-25, 2016, in Pushchino, Moscow Region, Russia (see http://photosynthesis2016.cellreg.org/ ).

Reduction of MLH1 and PMS2 confers temozolomide resistance and is associated with recurrence of glioblastoma.

PubMed

Shinsato, Yoshinari; Furukawa, Tatsuhiko; Yunoue, Shunji; Yonezawa, Hajime; Minami, Kentarou; Nishizawa, Yukihiko; Ikeda, Ryuji; Kawahara, Kohichi; Yamamoto, Masatatsu; Hirano, Hirofumi; Tokimura, Hiroshi; Arita, Kazunori

2013-12-01

Although there is a relationship between DNA repair deficiency and temozolomide (TMZ) resistance in glioblastoma (GBM), it remains unclear which molecule is associated with GBM recurrence. We isolated three TMZ-resistant human GBM cell lines and examined the expression of O6-methylguanine-DNA methyltransferase (MGMT) and mismatch repair (MMR) components. We used immunohistochemical analysis to compare MutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2) and MGMT expression in primary and recurrent GBM specimens obtained from GBM patients during TMZ treatment. We found a reduction in MLH1 expression and a subsequent reduction in PMS2 protein levels in TMZ-resistant cells. Furthermore, MLH1 or PMS2 knockdown confered TMZ resistance. In recurrent GBM tumours, the expression of MLH1 and PMS2 was reduced when compared to primary tumours.

Identification of potent orally active factor Xa inhibitors based on conjugation strategy and application of predictable fragment recommender system.

PubMed

Ishihara, Tsukasa; Koga, Yuji; Iwatsuki, Yoshiyuki; Hirayama, Fukushi

2015-01-15

Anticoagulant agents have emerged as a promising class of therapeutic drugs for the treatment and prevention of arterial and venous thrombosis. We investigated a series of novel orally active factor Xa inhibitors designed using our previously reported conjugation strategy to boost oral anticoagulant effect. Structural optimization of anthranilamide derivative 3 as a lead compound with installation of phenolic hydroxyl group and extensive exploration of the P1 binding element led to the identification of 5-chloro-N-(5-chloro-2-pyridyl)-3-hydroxy-2-{[4-(4-methyl-1,4-diazepan-1-yl)benzoyl]amino}benzamide (33, AS1468240) as a potent factor Xa inhibitor with significant oral anticoagulant activity. We also reported a newly developed Free-Wilson-like fragment recommender system based on the integration of R-group decomposition with collaborative filtering for the structural optimization process. Copyright © 2014 Elsevier Ltd. All rights reserved.

High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases.

PubMed

Valentini, Giseli; Gonçalves-Vidigal, Maria Celeste; Hurtado-Gonzales, Oscar P; de Lima Castro, Sandra Aparecida; Cregan, Perry B; Song, Qijian; Pastor-Corrales, Marcial A

2017-08-01

Co-segregation analysis and high-throughput genotyping using SNP, SSR, and KASP markers demonstrated genetic linkage between Ur-14 and Co-3 4 /Phg-3 loci conferring resistance to the rust, anthracnose and angular leaf spot diseases of common bean. Rust, anthracnose, and angular leaf spot are major diseases of common bean in the Americas and Africa. The cultivar Ouro Negro has the Ur-14 gene that confers broad spectrum resistance to rust and the gene cluster Co-3 4 /Phg-3 containing two tightly linked genes conferring resistance to anthracnose and angular leaf spot, respectively. We used co-segregation analysis and high-throughput genotyping of 179 F 2:3 families from the Rudá (susceptible) × Ouro Negro (resistant) cross-phenotyped separately with races of the rust and anthracnose pathogens. The results confirmed that Ur-14 and Co-3 4 /Phg-3 cluster in Ouro Negro conferred resistance to rust and anthracnose, respectively, and that Ur-14 and the Co-3 4 /Phg-3 cluster were closely linked. Genotyping the F 2:3 families, first with 5398 SNPs on the Illumina BeadChip BARCBEAN6K_3 and with 15 SSR, and eight KASP markers, specifically designed for the candidate region containing Ur-14 and Co-3 4 /Phg-3, permitted the creation of a high-resolution genetic linkage map which revealed that Ur-14 was positioned at 2.2 cM from Co-3 4 /Phg-3 on the short arm of chromosome Pv04 of the common bean genome. Five flanking SSR markers were tightly linked at 0.1 and 0.2 cM from Ur-14, and two flanking KASP markers were tightly linked at 0.1 and 0.3 cM from Co-3 4 /Phg-3. Many other SSR, SNP, and KASP markers were also linked to these genes. These markers will be useful for the development of common bean cultivars combining the important Ur-14 and Co-3 4 /Phg-3 genes conferring resistance to three of the most destructive diseases of common bean.

Molecular characterisation of the broad-spectrum resistance to powdery mildew conferred by the Stpk-V gene from the wild species Haynaldia villosa.

PubMed

Qian, C; Cui, C; Wang, X; Zhou, C; Hu, P; Li, M; Li, R; Xiao, J; Wang, X; Chen, P; Xing, L; Cao, A

2017-11-01

A key member of the Pm21 resistance gene locus, Stpk-V, derived from Haynaldia villosa, was shown to confer broad-spectrum resistance to wheat powdery mildew. The present study was planned to investigate the resistance mechanism mediated by Stpk-V. Transcriptome analysis was performed in Stpk-V transgenic plants and recipient Yangmai158 upon Bgt infection, and detailed histochemical observations were conducted. Chromosome location of Stpk-V orthologous genes in Triticeae species was conducted for evolutionary study and over-expression of Stpk-V both in barley and Arabidopsis was performed for functional study. The transcriptome results indicate, at the early infection stage, the ROS pathway, JA pathway and some PR proteins associated with the SA pathway were activated in both the resistant Stpk-V transgenic plants and susceptible Yangmai158. However, at the later infection stage, the genes up-regulated at the early stage were continuously held only in the transgenic plants, and a large number of new genes were also activated in the transgenic plants but not in Yangmai158. Results indicate that sustained activation of the early response genes combined with later-activated genes mediated by Stpk-V is critical for resistance in Stpk-V transgenic plants. Stpk-V orthologous genes in the representative grass species are all located on homologous group six chromosomes, indicating that Stpk-V is an ancient gene in the grasses. Over-expression of Stpk-V enhanced host resistance to powdery mildew in barley but not in Arabidopsis. Our results enable a better understanding of the resistance mechanism mediated by Stpk-V, and establish a solid foundation for its use in cereal breeding as a gene resource. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Anticoagulation by factor Xa inhibitors.

PubMed

Orfeo, T; Butenas, S; Brummel-Ziedins, K E; Gissel, M; Mann, K G

2010-08-01

Therapeutic agents that regulate blood coagulation are critical to the management of thrombotic disorders, with the selective targeting of factor (F) Xa emerging as a promising approach. To assess anticoagulant strategies targeting FXa. A deterministic computational model of tissue factor (Tf)-initiated thrombin generation and two empirical experimental systems (a synthetic coagulation proteome reconstruction using purified proteins and a whole blood model) were used to evaluate clinically relevant examples of the two available types of FXa-directed anticoagulants [an antithrombin (AT)-dependent agent, fondaparinux, and an AT-independent inhibitor, Rivaroxaban] in experimental regimens relevant to long-term (suppression of new Tf-initiated events) and acute (suppression of ongoing coagulation processes) clinical applications. Computational representations of each anticoagulant's efficacy in suppressing thrombin generation over a range of anticoagulant concentrations in both anticoagulation regimens were validated by results from corresponding empirical reconstructions and were consistent with those recommended for long-term and acute clinical applications, respectively. All three model systems suggested that Rivaroxaban would prove more effective in the suppression of an ongoing coagulation process than fondaparinux, reflecting its much higher reactivity toward the prothrombinase complex. The success of fondaparinux in acute settings in vivo is not explained solely by its properties as an FXa inhibitor. We have reported that FIXa contributes to the long-term capacity of clot-associated catalysts to restart a coagulation process, suggesting that the enhanced anti-FIXa activity of fondaparinux-AT may be critical to its success in acute settings in vivo. © 2010 International Society on Thrombosis and Haemostasis.

Molecular Dynamics Simulation of the Complex PBP-2x with Drug Cefuroxime to Explore the Drug Resistance Mechanism of Streptococcus suis R61

PubMed Central

Xia, Yingjie; Yang, Ming; Xiao, Jingfa; Yu, Jun

2012-01-01

Drug resistance of Streptococcus suis strains is a worldwide problem for both humans and pigs. Previous studies have noted that penicillin-binding protein (PBPs) mutation is one important cause of β-lactam antibiotic resistance. In this study, we used the molecular dynamics (MD) method to study the interaction differences between cefuroxime (CES) and PBP2x within two newly sequenced Streptococcus suis: drug-sensitive strain A7, and drug-resistant strain R61. The MM-PBSA results proved that the drug bound much more tightly to PBP2x in A7 (PBP2x-A7) than to PBP2x in R61 (PBP2x-R61). This is consistent with the evidently different resistances of the two strains to cefuroxime. Hydrogen bond analysis indicated that PBP2x-A7 preferred to bind to cefuroxime rather than to PBP2x-R61. Three stable hydrogen bonds were formed by the drug and PBP2x-A7, while only one unstable bond existed between the drug and PBP2x-R61. Further, we found that the Gln569, Tyr594, and Gly596 residues were the key mutant residues contributing directly to the different binding by pair wise energy decomposition comparison. By investigating the binding mode of the drug, we found that mutant residues Ala320, Gln553, and Thr595 indirectly affected the final phenomenon by topological conformation alteration. Above all, our results revealed some details about the specific interaction between the two PBP2x proteins and the drug cefuroxime. To some degree, this explained the drug resistance mechanism of Streptococcus suis and as a result could be helpful for further drug design or improvement. PMID:22563422

Molecular dynamics simulation of the complex PBP-2x with drug cefuroxime to explore the drug resistance mechanism of Streptococcus suis R61.

PubMed

Ge, Yan; Wu, Jiayan; Xia, Yingjie; Yang, Ming; Xiao, Jingfa; Yu, Jun

2012-01-01

Drug resistance of Streptococcus suis strains is a worldwide problem for both humans and pigs. Previous studies have noted that penicillin-binding protein (PBPs) mutation is one important cause of β-lactam antibiotic resistance. In this study, we used the molecular dynamics (MD) method to study the interaction differences between cefuroxime (CES) and PBP2x within two newly sequenced Streptococcus suis: drug-sensitive strain A7, and drug-resistant strain R61. The MM-PBSA results proved that the drug bound much more tightly to PBP2x in A7 (PBP2x-A7) than to PBP2x in R61 (PBP2x-R61). This is consistent with the evidently different resistances of the two strains to cefuroxime. Hydrogen bond analysis indicated that PBP2x-A7 preferred to bind to cefuroxime rather than to PBP2x-R61. Three stable hydrogen bonds were formed by the drug and PBP2x-A7, while only one unstable bond existed between the drug and PBP2x-R61. Further, we found that the Gln569, Tyr594, and Gly596 residues were the key mutant residues contributing directly to the different binding by pair wise energy decomposition comparison. By investigating the binding mode of the drug, we found that mutant residues Ala320, Gln553, and Thr595 indirectly affected the final phenomenon by topological conformation alteration. Above all, our results revealed some details about the specific interaction between the two PBP2x proteins and the drug cefuroxime. To some degree, this explained the drug resistance mechanism of Streptococcus suis and as a result could be helpful for further drug design or improvement.

The cold-induced defensin TAD1 confers resistance against snow mold and Fusarium head blight in transgenic wheat.

PubMed

Sasaki, Kentaro; Kuwabara, Chikako; Umeki, Natsuki; Fujioka, Mari; Saburi, Wataru; Matsui, Hirokazu; Abe, Fumitaka; Imai, Ryozo

2016-06-20

TAD1 (Triticum aestivum defensin 1) is induced during cold acclimation in winter wheat and encodes a plant defensin with antimicrobial activity. In this study, we demonstrated that recombinant TAD1 protein inhibits hyphal growth of the snow mold fungus, Typhula ishikariensis in vitro. Transgenic wheat plants overexpressing TAD1 were created and tested for resistance against T. ishikariensis. Leaf inoculation assays revealed that overexpression of TAD1 confers resistance against the snow mold. In addition, the TAD1-overexpressors showed resistance against Fusarium graminearum, which causes Fusarium head blight, a devastating disease in wheat and barley. These results indicate that TAD1 is a candidate gene to improve resistance against multiple fungal diseases in cereal crops. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel amino acid substitution Trp574Arg in acetolactate synthase (ALS) confers broad resistance to ALS-inhibiting herbicides in crabgrass (Digitaria sanguinalis).

PubMed

Li, Jian; Li, Mei; Gao, Xingxiang; Fang, Feng

2017-12-01

Crabgrass (Digitaria sanguinalis) is an annual monocotyledonous weed. In recent years, field applications of nicosulfuron have been ineffective in controlling crabgrass populations in Shandong Province, China. To investigate the mechanisms of resistance to nicosulfuron in crabgrass populations, the acetolactate synthase (ALS) gene fragment covering known resistance-confering mutation sites was amplified and sequenced. Dose-response experiments suggested that the resistant population SD13 (R) was highly resistant to nicosulfuron (resistance index R/S = 43.7) compared with the sensitive population SD22 (S). ALS gene sequencing revealed a Trp574Arg substitution in the SD13 population, and no other known resistance-conferring mutations were found. In vitro ALS enzyme assays further confirmed that the SD13 population was resistant to all tested ALS-inhibiting herbicides. The resistance pattern experiments revealed that, compared with SD22, the SD13 population exhibited broad-spectrum resistance to nicosulfuron (43.7-fold), imazethapyr (11.4-fold) and flumetsulam (16.1-fold); however, it did not develop resistance to atrazine, mesotrione and topramezone. This study demonstrated that Trp574Arg substitution was the main reason for crabgrass resistance to ALS-inhibiting herbicides. To our knowledge, this is the first report of Trp574Arg substitution in a weed species, and is the first report of target-site mechanisms of herbicide resistance for crabgrass. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

IL-21 signaling is essential for optimal host resistance against Mycobacterium tuberculosis infection.

PubMed

Booty, Matthew G; Barreira-Silva, Palmira; Carpenter, Stephen M; Nunes-Alves, Cláudio; Jacques, Miye K; Stowell, Britni L; Jayaraman, Pushpa; Beamer, Gillian; Behar, Samuel M

2016-11-07

IL-21 is produced predominantly by activated CD4 + T cells and has pleiotropic effects on immunity via the IL-21 receptor (IL-21R), a member of the common gamma chain (γ c ) cytokine receptor family. We show that IL-21 signaling plays a crucial role in T cell responses during Mycobacterium tuberculosis infection by augmenting CD8 + T cell priming, promoting T cell accumulation in the lungs, and enhancing T cell cytokine production. In the absence of IL-21 signaling, more CD4 + and CD8 + T cells in chronically infected mice express the T cell inhibitory molecules PD-1 and TIM-3. We correlate these immune alterations with increased susceptibility of IL-21R -/- mice, which have increased lung bacterial burden and earlier mortality compared to WT mice. Finally, to causally link the immune defects with host susceptibility, we use an adoptive transfer model to show that IL-21R -/- T cells transfer less protection than WT T cells. These results prove that IL-21 signaling has an intrinsic role in promoting the protective capacity of T cells. Thus, the net effect of IL-21 signaling is to enhance host resistance to M. tuberculosis. These data position IL-21 as a candidate biomarker of resistance to tuberculosis.

IL-21 signaling is essential for optimal host resistance against Mycobacterium tuberculosis infection

PubMed Central

Booty, Matthew G.; Barreira-Silva, Palmira; Carpenter, Stephen M.; Nunes-Alves, Cláudio; Jacques, Miye K.; Stowell, Britni L.; Jayaraman, Pushpa; Beamer, Gillian; Behar, Samuel M.

2016-01-01

IL-21 is produced predominantly by activated CD4+ T cells and has pleiotropic effects on immunity via the IL-21 receptor (IL-21R), a member of the common gamma chain (γc) cytokine receptor family. We show that IL-21 signaling plays a crucial role in T cell responses during Mycobacterium tuberculosis infection by augmenting CD8+ T cell priming, promoting T cell accumulation in the lungs, and enhancing T cell cytokine production. In the absence of IL-21 signaling, more CD4+ and CD8+ T cells in chronically infected mice express the T cell inhibitory molecules PD-1 and TIM-3. We correlate these immune alterations with increased susceptibility of IL-21R−/− mice, which have increased lung bacterial burden and earlier mortality compared to WT mice. Finally, to causally link the immune defects with host susceptibility, we use an adoptive transfer model to show that IL-21R−/− T cells transfer less protection than WT T cells. These results prove that IL-21 signaling has an intrinsic role in promoting the protective capacity of T cells. Thus, the net effect of IL-21 signaling is to enhance host resistance to M. tuberculosis. These data position IL-21 as a candidate biomarker of resistance to tuberculosis. PMID:27819295

Evaluation of dihydrofolate reductase and dihydropteroate synthetase genotypes that confer resistance to sulphadoxine-pyrimethamine in Plasmodium falciparum in Haiti

PubMed Central

2012-01-01

Background Malaria caused by Plasmodium falciparum infects roughly 30,000 individuals in Haiti each year. Haiti has used chloroquine (CQ) as a first-line treatment for malaria for many years and as a result there are concerns that malaria parasites may develop resistance to CQ over time. Therefore it is important to prepare for alternative malaria treatment options should CQ resistance develop. In many other malaria-endemic regions, antifolates, particularly pyrimethamine (PYR) and sulphadoxine (SDX) treatment combination (SP), have been used as an alternative when CQ resistance has developed. This study evaluated mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes that confer PYR and SDX resistance, respectively, in P. falciparum to provide baseline data in Haiti. This study is the first comprehensive study to examine PYR and SDX resistance genotypes in P. falciparum in Haiti. Methods DNA was extracted from dried blood spots and genotyped for PYR and SDX resistance mutations in P. falciparum using PCR and DNA sequencing methods. Sixty-one samples were genotyped for PYR resistance in codons 51, 59, 108 and 164 of the dhfr gene and 58 samples were genotyped for SDX resistance codons 436, 437, 540 of the dhps gene in P. falciparum. Results Thirty-three percent (20/61) of the samples carried a mutation at codon 108 (S108N) of the dhfr gene. No mutations in dhfr at codons 51, 59, 164 were observed in any of the samples. In addition, no mutations were observed in dhps at the three codons (436, 437, 540) examined. No significant difference was observed between samples collected in urban vs rural sites (Welch’s T-test p-value = 0.53 and permutations p-value = 0.59). Conclusion This study has shown the presence of the S108N mutation in P. falciparum that confers low-level PYR resistance in Haiti. However, the absence of SDX resistance mutations suggests that SP resistance may not be present in Haiti. These results have important

Selection for longevity confers resistance to low-temperature stress in Drosophila melanogaster.

PubMed

Luckinbill, L S

1998-03-01

One theory of the evolution of longevity says that improvement in life span is dependent on an increased ability to resist environmental stresses of all kind. Selective breeding of Drosophila melanogaster populations for longevity has demonstrably increased life span and also altered a number of other traits, such as resistance to starvation, desiccation, and ethanol fumes, and the ability to sustain longer flight. While the exact physiologic basis of some of these traits is not yet fully understood, at least some are known to derive from the properties of metabolic substrates of glycolysis. Improvement in those characters can depend partially, therefore, on altered stores of metabolites created from glycogen. Based on the known general relationship of some traits and the suspected basis in metabolism of others, we examine the possibility here that increased life span is accompanied by other traits that also confer physiologic resistance to stress. Specifically, we test the prediction that long-lived populations of fruit flies should be more resistant to low (prefreezing) and freezing temperature extremes. Both selected and control populations were found to be susceptible to prefreezing (1.5 degrees C) and freezing temperatures (0 degree C) here, but adults and pupae of the long-lived populations generally survived better in both situations, and at all durations of exposure. The resistance of individuals improved with acclimatization, but was superior in the long-lived populations whether thermal decline was rapid or stepwise. Cold resistant, long-lived populations also had significantly higher in vitro levels of glycerol, a cryoprotectant metabolite produced from glycogen. However, while adults and pupae of long-lived stocks were more resistant to cold, larvae of those stocks were more sensitive and survived relatively poorly at every length of exposure and acclimation. This surprising result implies that larvae maintain lower levels of cryoprotectant substances

Reduction of MLH1 and PMS2 confers temozolomide resistance and is associated with recurrence of glioblastoma

PubMed Central

Shinsato, Yoshinari; Furukawa, Tatsuhiko; Yunoue, Shunji; Yonezawa, Hajime; Minami, Kentarou; Nishizawa, Yukihiko; Ikeda, Ryuji; Kawahara, Kohichi; Yamamoto, Masatatsu; Hirano, Hirofumi; Tokimura, Hiroshi; Arita, Kazunori

2013-01-01

Although there is a relationship between DNA repair deficiency and temozolomide (TMZ) resistance in glioblastoma (GBM), it remains unclear which molecule is associated with GBM recurrence. We isolated three TMZ-resistant human GBM cell lines and examined the expression of O6-methylguanine-DNA methyltransferase (MGMT) and mismatch repair (MMR) components. We used immunohistochemical analysis to compare MutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2) and MGMT expression in primary and recurrent GBM specimens obtained from GBM patients during TMZ treatment. We found a reduction in MLH1 expression and a subsequent reduction in PMS2 protein levels in TMZ-resistant cells. Furthermore, MLH1 or PMS2 knockdown confered TMZ resistance. In recurrent GBM tumours, the expression of MLH1 and PMS2 was reduced when compared to primary tumours. PMID:24259277

P21 and p27: roles in carcinogenesis and drug resistance.

PubMed

Abukhdeir, Abde M; Park, Ben Ho

2008-07-01

Human cancers arise from an imbalance of cell growth and cell death. Key proteins that govern this balance are those that mediate the cell cycle. Several different molecular effectors have been identified that tightly regulate specific phases of the cell cycle, including cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors. Notably, loss of expression or function of two G1-checkpoint CDK inhibitors - p21 (CDKN1A) and p27 (CDKN1B) - has been implicated in the genesis or progression of many human malignancies. Additionally, there is a growing body of evidence suggesting that functional loss of p21 or p27 can mediate a drug-resistance phenotype. However, reports in the literature have also suggested p21 and p27 can promote tumours, indicating a paradoxical effect. Here, we review historic and recent studies of these two CDK inhibitors, including their identification, function, importance to carcinogenesis and finally their roles in drug resistance.

Catalog of Courses and Conferences, 1972-1973.

ERIC Educational Resources Information Center

Defense Civil Preparedness Agency (DOD), Battle Creek, MI.

The types of courses, conferences, and workshops sponsored by the Defense Civil Preparedness Agency tuition-free are listed and described in this pamphlet. The training programs are not representative of all civil defense training available. The 21 courses and conferences listed are: Conferences for Public Officials; Conferences for Business and…

49 CFR 178.358 - Specification 21PF fire and shock resistant, phenolic-foam insulated, metal overpack.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Specification 21PF fire and shock resistant, phenolic-foam insulated, metal overpack. 178.358 Section 178.358 Transportation Other Regulations Relating...) Materials § 178.358 Specification 21PF fire and shock resistant, phenolic-foam insulated, metal overpack. ...

49 CFR 178.358 - Specification 21PF fire and shock resistant, phenolic-foam insulated, metal overpack.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Specification 21PF fire and shock resistant, phenolic-foam insulated, metal overpack. 178.358 Section 178.358 Transportation Other Regulations Relating... Class 7 (Radioactive) Materials § 178.358 Specification 21PF fire and shock resistant, phenolic-foam...

Emerging frontiers in healthcare research and delivery.: the 16th Annual HMO Research Network Conference, March 21-24, 2010, Austin, Texas.

PubMed

Stevens, Alan B; Sanghi, Sandhya

2010-12-01

The Health Maintenance Organization Research Network (HMORN), a consortium of 16 healthcare delivery systems with integrated research centers, held their 16(th) annual conference in Austin, Texas from March 21-24, 2010. The conference was hosted by Scott & White Healthcare. Its theme "Emerging Frontiers in Healthcare Research and Delivery" reflected the objective of the conference which was to build synergy among scientists and clinicians to influence the health of the nation; to demonstrate the network's commitment to reach beyond traditional collaborators; discuss tools and technologies; and to expand opportunities for public-private partnerships in cutting-edge healthcare research and delivery. More than 320 researchers and healthcare professionals, representing each of the member HMOs, participated in this conference. Representatives from the AHRQ, CDC, NCI and NIH met with researchers to advance the quality and breadth of public domain research in HMOs. The objective of this article is to provide information about the HMORN and its 16(th) annual conference.

21 CFR 514.5 - Presubmission conferences.

Code of Federal Regulations, 2013 CFR

2013-04-01

... resolution. FDA is committed to resolving differences between a potential applicant and FDA reviewing... communication. (b) Requesting a presubmission conference. A potential applicant is entitled to one or more... establishing part or all of a submission or investigational requirement. A potential applicant's request for a...

21 CFR 514.5 - Presubmission conferences.

Code of Federal Regulations, 2012 CFR

2012-04-01

... resolution. FDA is committed to resolving differences between a potential applicant and FDA reviewing... communication. (b) Requesting a presubmission conference. A potential applicant is entitled to one or more... establishing part or all of a submission or investigational requirement. A potential applicant's request for a...

21 CFR 514.5 - Presubmission conferences.

Code of Federal Regulations, 2010 CFR

2010-04-01

... resolution. FDA is committed to resolving differences between a potential applicant and FDA reviewing... communication. (b) Requesting a presubmission conference. A potential applicant is entitled to one or more... establishing part or all of a submission or investigational requirement. A potential applicant's request for a...

21 CFR 514.5 - Presubmission conferences.

Code of Federal Regulations, 2011 CFR

2011-04-01

... resolution. FDA is committed to resolving differences between a potential applicant and FDA reviewing... communication. (b) Requesting a presubmission conference. A potential applicant is entitled to one or more... establishing part or all of a submission or investigational requirement. A potential applicant's request for a...

21 CFR 514.5 - Presubmission conferences.

Code of Federal Regulations, 2014 CFR

2014-04-01

... resolution. FDA is committed to resolving differences between a potential applicant and FDA reviewing... communication. (b) Requesting a presubmission conference. A potential applicant is entitled to one or more... establishing part or all of a submission or investigational requirement. A potential applicant's request for a...

Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death.

PubMed

Narayanan, Kannan Badri; Ali, Manaf; Barclay, Barry J; Cheng, Qiang Shawn; D'Abronzo, Leandro; Dornetshuber-Fleiss, Rita; Ghosh, Paramita M; Gonzalez Guzman, Michael J; Lee, Tae-Jin; Leung, Po Sing; Li, Lin; Luanpitpong, Suidjit; Ratovitski, Edward; Rojanasakul, Yon; Romano, Maria Fiammetta; Romano, Simona; Sinha, Ranjeet K; Yedjou, Clement; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G; Ryan, Elizabeth P; Colacci, Annamaria; Hamid, Roslida A; Mondello, Chiara; Raju, Jayadev; Salem, Hosni K; Woodrick, Jordan; Scovassi, A Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Kim, Seo Yun; Bisson, William H; Lowe, Leroy; Park, Hyun Ho

2015-06-01

Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A Gene Homologous to rRNA Methylase Genes Confers Erythromycin and Clindamycin Resistance in Bifidobacterium breve.

PubMed

Martínez, Noelia; Luque, Roberto; Milani, Christian; Ventura, Marco; Bañuelos, Oscar; Margolles, Abelardo

2018-05-15

Bifidobacteria are mutualistic intestinal bacteria, and their presence in the human gut has been associated with health-promoting activities. The presence of antibiotic resistance genes in this genus is controversial, since, although bifidobacteria are nonpathogenic microorganisms, they could serve as reservoirs of resistance determinants for intestinal pathogens. However, until now, few antibiotic resistance determinants have been functionally characterized in this genus. In this work, we show that Bifidobacterium breve CECT7263 displays atypical resistance to erythromycin and clindamycin. In order to delimit the genomic region responsible for the observed resistance phenotype, a library of genomic DNA was constructed and a fragment of 5.8 kb containing a gene homologous to rRNA methylase genes was able to confer erythromycin resistance in Escherichia coli This genomic region seems to be very uncommon, and homologs of the gene have been detected in only one strain of Bifidobacterium longum and two other strains of B. breve In this context, analysis of shotgun metagenomics data sets revealed that the gene is also uncommon in the microbiomes of adults and infants. The structural gene and its upstream region were cloned into a B. breve -sensitive strain, which became resistant after acquiring the genetic material. In vitro conjugation experiments did not allow us to detect gene transfer to other recipients. Nevertheless, prediction of genes potentially acquired through horizontal gene transfer events revealed that the gene is located in a putative genomic island. IMPORTANCE Bifidobacterium breve is a very common human intestinal bacterium. Often described as a pioneer microorganism in the establishment of early-life intestinal microbiota, its presence has been associated with several beneficial effects for the host, including immune stimulation and protection against infections. Therefore, some strains of this species are considered probiotics. In relation to this

Caveolin-1 Confers Resistance of Hepatoma Cells to Anoikis by Activating IGF-1 Pathway.

PubMed

Tang, Wenqing; Feng, Xuemei; Zhang, Si; Ren, Zhenggang; Liu, Yinkun; Yang, Biwei; lv, Bei; Cai, Yu; Xia, Jinglin; Ge, Ningling

2015-01-01

Anoikis resistance is a prerequisite for hepatocellular carcinoma (HCC) metastasis. The role of Caveolin-1 (CAV1) in anoikis resistance of HCC remains unclear. The oncogenic effect of CAV1 on anchor-independent growth and anoikis resistance was investigated by overexpression and knockdown of CAV1 in hepatoma cells. IGF-1 pathway and its downstream signals were detected by immunoblot analysis. Caveolae invagination and IGF-1R internalization was studied by electron microscopy and (125)I-IGF1 internalization assay, respectively. The role of IGF-1R and tyrosine-14 residue (Y-14) of CAV1 was explored by deletion experiment and mutation experiment, respectively. The correlation of CAV1 and IGF-1R was further examined by immunochemical analysis in 120 HCC specimens. CAV1 could promote anchor-independent growth and anoikis resistance in hepatoma cells. CAV1-overexpression increased the expression of IGF-1R and subsequently activated PI3K/Akt and RAF/MEK/ERK pathway, while CAV1 knockdown showed the opposite effect. The mechanism study revealed that CAV1 facilitated caveolae invagination and (125)I-IGF1 internalization. IGF-1R deletion or Y-14 mutation reversed CAV1 mediated anchor-independent growth and anoikis resistance. In addition, CAV1 expression was positively related to IGF-1R expression in human HCC tissues. CAV1 confers resistance of hepatoma cells to anoikis by activating IGF-1 pathway, providing a potential therapeutic target for HCC metastasis. © 2015 S. Karger AG, Basel.

Haemophilus parasuis CpxRA two-component system confers bacterial tolerance to environmental stresses and macrolide resistance.

PubMed

Cao, Qi; Feng, Fenfen; Wang, Huan; Xu, Xiaojuan; Chen, Huanchun; Cai, Xuwang; Wang, Xiangru

2018-01-01

Haemophilus parasuis is an opportunistic pathogen localized in the upper respiratory tracts of pigs, its infection begins from bacterial survival under complex conditions, like hyperosmosis, oxidative stress, phagocytosis, and sometimes antibiotics as well. The two-component signal transduction (TCST) system serves as a common stimulus-response mechanism that allows microbes to sense and respond to diverse environmental conditions via a series of phosphorylation reactions. In this study, we investigated the role of TCST system CpxRA in H. parasuis in response to different environmental stimuli by constructing the ΔcpxA and ΔcpxR single deletion mutants as well as the ΔcpxRA double deletion mutant from H. parasuis serotype 4 isolate JS0135. We demonstrated that H. parasuis TCST system CpxRA confers bacterial tolerance to stresses and bactericidal antibiotics. The CpxR was found to play essential roles in mediating oxidative stress, osmotic stresses and alkaline pH stress tolerance, as well as macrolide resistance (i.e. erythromycin), but the CpxA deletion did not decrease bacterial resistance to abovementioned stresses. Moreover, we found via RT-qPCR approach that HAPS_RS00160 and HAPS_RS09425, both encoding multidrug efflux pumps, were significantly decreased in erythromycin challenged ΔcpxR and ΔcpxRA mutants compared with wild-type strain JS0135. These findings characterize the role of the TCST system CpxRA in H. parasuis conferring stress response tolerance and bactericidal resistance, which will deepen our understanding of the pathogenic mechanism in H. parasuis. Copyright © 2017 Elsevier GmbH. All rights reserved.

International conference on Functional Materials and Nanotechnologies (FM&NT-2013), 21-24 April 2013, Tartu, Estonia

NASA Astrophysics Data System (ADS)

Nõmmiste, Ergo; Kirm, Marco; Plank, Toomas

2014-04-01

The annual international conference Functional Materials and Nanotechnologies (FM&NT) was started in 2006 by scientists from the Institute of Solid State Physics, University of Latvia. The warm welcome and open atmosphere of this scientific conference has turned it into an event where people from different countries and different fields come and meet under the shared umbrella of functional materials and nanotechnology. It is particularly important for early stage scientists who are looking for new knowledge and contacts with people from various fields to build their own network. Our Latvian colleagues, with their success in internationalization, made us neighbouring Estonians so jealous that we could not help but propose organising the conference every second year in Estonia. In a way, this conference is a continuation of the idea of the famous Baltic seminars which took place over several decades in the last century. Due to political constraints, these seminars were only open to scientists of former Eastern Europe countries, but had a great popularity and attendance from over the whole Soviet Union. Many collaborations started from the initial personal contact between scientists at these twice yearly seminars, held alternately in Latvia and Estonia. At the FM&NT 2012 conference, the decision was made that Institute of Physics, University of Tartu would organise the next event in Tartu in 2013. FM&NT-2013 was hence held in Tartu (Estonia) from 21-24 April 2013 at the Dorpat Conference Centre. The main selected topics of the conference were: (i) multifunctional materials, (ii) nanomaterials, (iii) materials for sustainable energy applications and (vi) theory. Additionally, the focus in this conference was on studies with the help of synchrotron radiation and other novel light sources such as free electron lasers. The conference provided an opportunity for 300 scientists from 21 countries to meet, establish contacts, exchange knowledge and discuss their research

Physical Localization of a Locus from Agropyron cristatum Conferring Resistance to Stripe Rust in Common Wheat

PubMed Central

Song, Liqiang; Han, Haiming; Zhou, Shenghui; Zhang, Jinpeng; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

2017-01-01

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), one of the wild relatives of wheat, exhibits resistance to stripe rust. In this study, wheat-A. cristatum 6P disomic addition line 4844-12 also exhibited resistance to stripe rust. To identify the stripe rust resistance locus from A. cristatum 6P, ten translocation lines, five deletion lines and the BC2F2 and BC3F2 populations of two wheat-A. cristatum 6P whole-arm translocation lines were tested with a mixture of two races of Pst in two sites during 2015–2016 and 2016–2017, being genotyped with genomic in situ hybridization (GISH) and molecular markers. The result indicated that the locus conferring stripe rust resistance was located on the terminal 20% of 6P short arm’s length. Twenty-nine 6P-specific sequence-tagged-site (STS) markers mapped on the resistance locus have been acquired, which will be helpful for the fine mapping of the stripe rust resistance locus. The stripe rust-resistant translocation lines were found to carry some favorable agronomic traits, which could facilitate their use in wheat improvement. Collectively, the stripe rust resistance locus from A. cristatum 6P could be a novel resistance source and the screened stripe rust-resistant materials will be valuable for wheat disease breeding. PMID:29137188

Physical Localization of a Locus from Agropyron cristatum Conferring Resistance to Stripe Rust in Common Wheat.

PubMed

Zhang, Zhi; Song, Liqiang; Han, Haiming; Zhou, Shenghui; Zhang, Jinpeng; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

2017-11-13

Stripe rust, caused by Puccinia striiformis f. sp. tritici ( Pst ), is one of the most destructive diseases of wheat ( Triticum aestivum L.) worldwide. Agropyron cristatum (L.) Gaertn. (2 n = 28, PPPP), one of the wild relatives of wheat, exhibits resistance to stripe rust. In this study, wheat- A . cristatum 6P disomic addition line 4844-12 also exhibited resistance to stripe rust. To identify the stripe rust resistance locus from A . cristatum 6P, ten translocation lines, five deletion lines and the BC₂F₂ and BC₃F₂ populations of two wheat- A . cristatum 6P whole-arm translocation lines were tested with a mixture of two races of Pst in two sites during 2015-2016 and 2016-2017, being genotyped with genomic in situ hybridization (GISH) and molecular markers. The result indicated that the locus conferring stripe rust resistance was located on the terminal 20% of 6P short arm's length. Twenty-nine 6P-specific sequence-tagged-site (STS) markers mapped on the resistance locus have been acquired, which will be helpful for the fine mapping of the stripe rust resistance locus. The stripe rust-resistant translocation lines were found to carry some favorable agronomic traits, which could facilitate their use in wheat improvement. Collectively, the stripe rust resistance locus from A . cristatum 6P could be a novel resistance source and the screened stripe rust-resistant materials will be valuable for wheat disease breeding.

Sulfated Low Molecular Weight Lignins, Allosteric Inhibitors of Coagulation Proteinases via the Heparin Binding Site, Significantly Alter the Active Site of Thrombin and Factor Xa Compared to Heparin

PubMed Central

Henry, Brian L.; Desai, Umesh R.

2014-01-01

Sulfated low molecular weight lignins (LMWLs) have been found to bind in the heparin binding sites of coagulation proteinases. LMWLs represent a library of diverse non-carbohydrate, aromatic molecules which are structures different from heparin, but still potently inhibit thrombin and factor Xa. To better understand their mechanism of action, we studied the effects of three sulfated LMWLs (CDSO3, FDSO3, and SDSO3) on the active sites of thrombin and factor Xa. LMWLs were found to uniformly inhibit the catalytic activity of thrombin and factor Xa, regardless of the substrate used. Michaelis-Menten kinetic studies indicate that maximal velocity of hydrolysis of each chromogenic substrate decreases significantly in the presence of sulfated LMWLs, while the effect on Michaelis constant is dependent on the nature of the substrate. These studies indicate that LMWLs inhibit thrombin and factor Xa through allosteric disruption of the catalytic apparatus, specifically through the catalytic step. As opposed to heparin, LMWLs significantly alter the binding of the active site fluorescent ligand p-aminobenzamidine. LMWLs also had a greater effect on the molecular orientation of fluorescein-labeled His 57 than heparin. The molecular geometry surrounding the most important catalytic amino acid, Ser 195, was significantly altered by the binding of LMWLs while heparin had no measurable effect on Ser 195. These results further advance the concept of sulfated LMWLs as heparin mimics and will aid the design of anticoagulants based on their novel scaffold. PMID:25242245

Sulfated low molecular weight lignins, allosteric inhibitors of coagulation proteinases via the heparin binding site, significantly alter the active site of thrombin and factor xa compared to heparin.

PubMed

Henry, Brian L; Desai, Umesh R

2014-11-01

Sulfated low molecular weight lignins (LMWLs) have been found to bind in the heparin binding sites of coagulation proteinases. LMWLs represent a library of diverse non-carbohydrate, aromatic molecules which are structures different from heparin, but still potently inhibit thrombin and factor Xa. To better understand their mechanism of action, we studied the effects of three sulfated LMWLs (CDSO3, FDSO3, and SDSO3) on the active sites of thrombin and factor Xa. LMWLs were found to uniformly inhibit the catalytic activity of thrombin and factor Xa, regardless of the substrate used. Michaelis-Menten kinetic studies indicate that maximal velocity of hydrolysis of each chromogenic substrate decreases significantly in the presence of sulfated LMWLs, while the effect on Michaelis constant is dependent on the nature of the substrate. These studies indicate that LMWLs inhibit thrombin and factor Xa through allosteric disruption of the catalytic apparatus, specifically through the catalytic step. As opposed to heparin, LMWLs significantly alter the binding of the active site fluorescent ligand p-aminobenzamidine. LMWLs also had a greater effect on the molecular orientation of fluorescein-labeled His 57 than heparin. The molecular geometry surrounding the most important catalytic amino acid, Ser 195, was significantly altered by the binding of LMWLs while heparin had no measurable effect on Ser 195. These results further advance the concept of sulfated LMWLs as heparin mimics and will aid the design of anticoagulants based on their novel scaffold. Copyright © 2014 Elsevier Ltd. All rights reserved.

Population Distribution of Beta-Lactamase Conferring Resistance to Third-Generation Cephalosporins in Human Clinical Enterobacteriaceae in The Netherlands

PubMed Central

Voets, Guido M.; Platteel, Tamara N.; Fluit, Ad C.; Scharringa, Jelle; Schapendonk, Claudia M.; Stuart, James Cohen; Bonten, Marc J. M.; Hall, Maurine A. L.

2012-01-01

There is a global increase in infections caused by Enterobacteriaceae with plasmid-borne β-lactamases that confer resistance to third-generation cephalosporins. The epidemiology of these bacteria is not well understood, and was, therefore, investigated in a selection of 636 clinical Enterobacteriaceae with a minimal inhibitory concentration >1 mg/L for ceftazidime/ceftriaxone from a national survey (75% E. coli, 11% E. cloacae, 11% K. pneumoniae, 2% K. oxytoca, 2% P. mirabilis). Isolates were investigated for extended-spectrum β-lactamases (ESBLs) and ampC genes using microarray, PCR, gene sequencing and molecular straintyping (Diversilab and multi-locus sequence typing (MLST)). ESBL genes were demonstrated in 512 isolates (81%); of which 446 (87%) belonged to the CTX-M family. Among 314 randomly selected and sequenced isolates, bla CTX-M-15 was most prevalent (n = 124, 39%), followed by bla CTX-M-1 (n = 47, 15%), bla CTX-M-14 (n = 15, 5%), bla SHV-12 (n = 24, 8%) and bla TEM-52 (n = 13, 4%). Among 181 isolates with MIC ≥16 mg/L for cefoxitin plasmid encoded AmpCs were detected in 32 and 27 were of the CMY-2 group. Among 102 E. coli isolates with MIC ≥16 mg/L for cefoxitin ampC promoter mutations were identified in 29 (28%). Based on Diversilab genotyping of 608 isolates (similarity cut-off >98%) discriminatory indices of bacteria with ESBL and/or ampC genes were 0.994, 0.985 and 0.994 for E. coli, K. pneumoniae and E. cloacae, respectively. Based on similarity cut-off >95% two large clusters of E. coli were apparent (of 43 and 30 isolates) and 21 of 21 that were typed by belonged to ST131 of which 13 contained bla CTX-M-15. Our findings demonstrate that bla CTX-M-15 is the most prevalent ESBL and we report a larger than previously reported prevalence of ampC genes among Enterobacteriaceae responsible for resistance to third-generation cephalosporins. PMID:23284886

Academic Conferences: Representative and Resistant Sites for Higher Education Research

ERIC Educational Resources Information Center

Henderson, Emily F.

2015-01-01

The overarching argument made in this article is twofold. Firstly, academic conferences are posited as sites for higher education research. Secondly, the well-recognised emotional and social processes of conferences are used to make space at the boundaries of higher education research for psychosocial analysis. The article theorises conferences in…

Target-site mutations conferring resistance to glyphosate in feathertop Rhodes grass (Chloris virgata) populations in Australia.

PubMed

Ngo, The D; Krishnan, Mahima; Boutsalis, Peter; Gill, Gurjeet; Preston, Christopher

2018-05-01

Chloris virgata is a warm-season, C 4 , annual grass weed affecting field crops in northern Australia that has become an emerging weed in southern Australia. Four populations with suspected resistance to glyphosate were collected in South Australia, Queensland and New South Wales, Australia, and compared with one susceptible (S) population to confirm glyphosate resistance and elucidate possible mechanisms of resistance. Based on the rate of glyphosate required to kill 50% of treated plants (LD 50 ), glyphosate resistance (GR) was confirmed in four populations of C. virgata (V12, V14.2, V14.16 and V15). GR plants were 2-9.7-fold more resistant and accumulated less shikimate after glyphosate treatment than S plants. GR and S plants did not differ in glyphosate absorption and translocation. Target-site EPSPS mutations corresponding to Pro-106-Leu (V14.2) and Pro-106-Ser (V15, V14.16 and V12) substitutions were found in GR populations. The population with Pro-106-Leu substitution was 2.9-4.9-fold more resistant than the three other populations with Pro-106-Ser substitution. This report confirms glyphosate resistance in C. virgata and shows that target-site EPSPS mutations confer resistance to glyphosate in this species. The evolution of glyphosate resistance in C. virgata highlights the need to identify alternative control tactics. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

IRE-1α promotes viral infection by conferring resistance to apoptosis

PubMed Central

Fink, Susan L.; Jayewickreme, Teshika R.; Molony, Ryan D.; Iwawaki, Takao; Landis, Charles S.; Lindenbach, Brett D.; Iwasaki, Akiko

2017-01-01

The unfolded protein response (UPR) is an ancient cellular pathway that detects and alleviates protein-folding stresses. The UPR components X-box binding protein 1 (XBP1) and inositol-requiring enzyme 1α (IRE1α) promote type I interferon (IFN) responses. Here, we found that Xbp1-deficient mouse embryonic fibroblasts and macrophages had impaired antiviral resistance. Unexpectedly, this was not because of a defect in type I IFN responses, but rather an inability of Xbp1-deficient cells to undergo viral-induced apoptosis. The ability to undergo apoptosis directly limited infection in WT cells. Xbp1-deficient cells were generally resistant to the intrinsic pathway of apoptosis through an indirect mechanism involving activation of the nuclease IRE1α. We observed an IRE1α-dependent reduction in the abundance of the pro-apoptotic microRNA miR-125a, and a corresponding increase in the amounts of the members of the anti-apoptotic Bcl2 family. The activation of IRE1α by the hepatitis C virus (HCV) protein NS4B in Xbp1-proficient cells also conferred apoptosis resistance and promoted viral replication. Furthermore, we found evidence of IRE1α activation and decreased miR-125a abundance in liver biopsies from patients infected with HCV compared to those in the livers of healthy controls. Our results reveal a pro-survival role for IRE1α in virally infected cells, and suggest a possible target for IFN-independent antiviral therapy. PMID:28588082

A novel blast resistance gene, Pi54rh cloned from wild species of rice, Oryza rhizomatis confers broad spectrum resistance to Magnaporthe oryzae.

PubMed

Das, Alok; Soubam, D; Singh, P K; Thakur, S; Singh, N K; Sharma, T R

2012-06-01

The dominant rice blast resistance gene, Pi54 confers resistance to Magnaporthe oryzae in different parts of India. In our effort to identify more effective forms of this gene, we isolated an orthologue of Pi54 named as Pi54rh from the blast-resistant wild species of rice, Oryza rhizomatis, using allele mining approach and validated by complementation. The Pi54rh belongs to CC-NBS-LRR family of disease resistance genes with a unique Zinc finger (C(3)H type) domain. The 1,447 bp Pi54rh transcript comprises of 101 bp 5'-UTR, 1,083 bp coding region and 263 bp 3'-UTR, driven by pathogen inducible promoter. We showed the extracellular localization of Pi54rh protein and the presence of glycosylation, myristoylation and phosphorylation sites which implicates its role in signal transduction process. This is in contrast to other blast resistance genes that are predicted to be intracellular NBS-LRR-type resistance proteins. The Pi54rh was found to express constitutively at basal level in the leaves, but upregulates 3.8-fold at 96 h post-inoculation with the pathogen. Functional validation of cloned Pi54rh gene using complementation test showed high degree of resistance to seven isolates of M. oryzae collected from different geographical locations of India. In this study, for the first time, we demonstrated that a rice blast resistance gene Pi54rh cloned from wild species of rice provides broad spectrum resistance to M. oryzae hence can be used in rice improvement breeding programme.

A Novel Glycolipid Biosurfactant Confers Grazing Resistance upon Pantoea ananatis BRT175 against the Social Amoeba Dictyostelium discoideum

PubMed Central

Smith, Derek D. N.; Nickzad, Arvin

2016-01-01

ABSTRACT Pantoea is a versatile genus of bacteria with both plant- and animal-pathogenic strains, some of which have been suggested to cause human infections. There is, however, limited knowledge on the potential determinants used for host association and pathogenesis in animal systems. In this study, we used the model host Dictyostelium discoideum to show that isolates of Pantoea ananatis exhibit differential grazing susceptibility, with some being resistant to grazing by the amoebae. We carried out a high-throughput genetic screen of one grazing-resistant isolate, P. ananatis BRT175, using the D. discoideum pathosystem to identify genes responsible for the resistance phenotype. Among the 26 candidate genes involved in grazing resistance, we identified rhlA and rhlB, which we show are involved in the biosynthesis of a biosurfactant that enables swarming motility in P. ananatis BRT175. Using liquid chromatography-mass spectrometry (LC-MS), the biosurfactant was shown to be a glycolipid with monohexose-C10-C10 as the primary congener. We show that this novel glycolipid biosurfactant is cytotoxic to the amoebae and is capable of compromising cellular integrity, leading to cell lysis. The production of this biosurfactant may be important for bacterial survival in the environment and could contribute to the establishment of opportunistic infections. IMPORTANCE The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are important for the production of a biosurfactant that confers grazing resistance against the social amoeba Dictyostelium discoideum. We show that the biosurfactant, which exhibits cytotoxicity toward the amoebae, is a glycolipid that incorporates a hexose rather than rhamnose. The production of this biosurfactant may confer a competitive advantage in the environment and could potentially contribute to the establishment of opportunistic infections. PMID

Identification and characterization of wheat stem rust resistance gene Sr21 effective against the Ug99 race group at high temperature

PubMed Central

Chen, Shisheng; Zhang, Wenjun; Bolus, Stephen; Rouse, Matthew N.

2018-01-01

Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a devastating foliar disease. The Ug99 race group has combined virulence to most stem rust (Sr) resistance genes deployed in wheat and is a threat to global wheat production. Here we identified a coiled-coil, nucleotide-binding leucine-rich repeat protein (NLR) completely linked to the Ug99 resistance gene Sr21 from Triticum monococcum. Loss-of-function mutations and transgenic complementation confirmed that this gene is Sr21. Sr21 transcripts were significantly higher at high temperatures, and this was associated with significant upregulation of pathogenesis related (PR) genes and increased levels of resistance at those temperatures. Introgression of Sr21 into hexaploid wheat resulted in lower levels of resistance than in diploid wheat, but transgenic hexaploid wheat lines with high levels of Sr21 expression showed high levels of resistance. Sr21 can be a valuable component of transgenic cassettes or gene pyramids combining multiple resistance genes against Ug99. PMID:29614079

OsSERK1 regulates rice development but not immunity to Xanthomonas oryzae pv. oryzae or Magnaporthe oryzae.

PubMed

Zuo, Shimin; Zhou, Xiaogang; Chen, Mawsheng; Zhang, Shilu; Schwessinger, Benjamin; Ruan, Deling; Yuan, Can; Wang, Jing; Chen, Xuewei; Ronald, Pamela C

2014-12-01

Somatic embryogenesis receptor kinase (SERK) proteins play pivotal roles in regulation of plant development and immunity. The rice genome contains two SERK genes, OsSerk1 and OsSerk2. We previously demonstrated that OsSerk2 is required for rice Xa21-mediated resistance to Xanthomonas oryzae pv. oryzae (Xoo) and for normal development. Here we report the molecular characterization of OsSerk1. Overexpression of OsSerk1 results in a semi-dwarf phenotype whereas silencing of OsSerk1 results in a reduced angle of the lamina joint. OsSerk1 is not required for rice resistance to Xoo or Magnaporthe oryzae. Overexpression of OsSerk1 in OsSerk2-silenced lines complements phenotypes associated with brassinosteroid (BR) signaling defects, but not the disease resistance phenotype mediated by Xa21. In yeast, OsSERK1 interacts with itself forming homodimers, and also interacts with the kinase domains of OsSERK2 and BRI1, respectively. OsSERK1 is a functional protein kinase capable of auto-phosphorylation in vitro. We conclude that, whereas OsSERK2 regulates both rice development and immunity, OsSERK1 functions in rice development but not immunity to Xoo and M. oryzae. © 2014 Institute of Botany, Chinese Academy of Sciences.

The Chromosomal Arsenic Resistance Genes of Thiobacillus ferrooxidans Have an Unusual Arrangement and Confer Increased Arsenic and Antimony Resistance to Escherichia coli

PubMed Central

Butcher, Bronwyn G.; Deane, Shelly M.; Rawlings, Douglas E.

2000-01-01

The chromosomal arsenic resistance genes of the acidophilic, chemolithoautotrophic, biomining bacterium Thiobacillus ferrooxidans were cloned and sequenced. Homologues of four arsenic resistance genes, arsB, arsC, arsH, and a putative arsR gene, were identified. The T. ferrooxidans arsB (arsenite export) and arsC (arsenate reductase) gene products were functional when they were cloned in an Escherichia coli ars deletion mutant and conferred increased resistance to arsenite, arsenate, and antimony. Therefore, despite the fact that the ars genes originated from an obligately acidophilic bacterium, they were functional in E. coli. Although T. ferrooxidans is gram negative, its ArsC was more closely related to the ArsC molecules of gram-positive bacteria. Furthermore, a functional trxA (thioredoxin) gene was required for ArsC-mediated arsenate resistance in E. coli; this finding confirmed the gram-positive ArsC-like status of this resistance and indicated that the division of ArsC molecules based on Gram staining results is artificial. Although arsH was expressed in an E. coli-derived in vitro transcription-translation system, ArsH was not required for and did not enhance arsenic resistance in E. coli. The T. ferrooxidans ars genes were arranged in an unusual manner, and the putative arsR and arsC genes and the arsBH genes were translated in opposite directions. This divergent orientation was conserved in the four T. ferrooxidans strains investigated. PMID:10788346

Inheritance of resistance to watermelon mosaic virus in the cucumber line TMG-1: tissue-specific expression and relationship to zucchini yellow mosaic virus resistance.

PubMed

Wai, T; Grumet, R

1995-09-01

The inbred cucumber (Cucumis sativus L.) line TMG-1 is resistant to three potyviruses:zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and the watermelon strain of papaya ringspot virus (PRSV-W). The genetics of resistance to WMV and the relationship of WMV resistance to ZYMV resistance were examined. TMG-1 was crossed with WI-2757, a susceptible inbred line. F1, F2 and backcross progeny populations were screened for resistance to WMV and/or ZYMV. Two independently assorting factors conferred resistance to WMV. One resistance was conferred by a single recessive gene from TMG-1 (wmv-2). The second resistance was conferred by an epistatic interaction between a second recessive gene from TMG-1 (wmv-3) and either a dominant gene from WI-2757 (Wmv-4) or a third recessive gene from TMG-1 (wmv-4) located 20-30 cM from wmv-3. The two resistances exhibited tissue-specific expression. Resistance conferred by wmv-2 was expressed in the cotyledons and throughout the plant. Resistance conferred by wmv-3 + Wmv-4 (or wmv-4) was expressed only in true leaves. The gene conferring resistance to ZYMV appeared to be the same as, or tightly linked to one of the WMV resistance genes, wmv-3.

Alkamides Activate Jasmonic Acid Biosynthesis and Signaling Pathways and Confer Resistance to Botrytis cinerea in Arabidopsis thaliana

PubMed Central

Méndez-Bravo, Alfonso; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Raya-González, Javier; Ramírez-Chávez, Enrique; Molina-Torres, Jorge; Guevara-García, Angel A.; López-Bucio, José; Herrera-Estrella, Luis

2011-01-01

Alkamides are fatty acid amides of wide distribution in plants, structurally related to N-acyl-L-homoserine lactones (AHLs) from Gram-negative bacteria and to N- acylethanolamines (NAEs) from plants and mammals. Global analysis of gene expression changes in Arabidopsis thaliana in response to N-isobutyl decanamide, the most highly active alkamide identified to date, revealed an overrepresentation of defense-responsive transcriptional networks. In particular, genes encoding enzymes for jasmonic acid (JA) biosynthesis increased their expression, which occurred in parallel with JA, nitric oxide (NO) and H2O2 accumulation. The activity of the alkamide to confer resistance against the necrotizing fungus Botrytis cinerea was tested by inoculating Arabidopsis detached leaves with conidiospores and evaluating disease symptoms and fungal proliferation. N-isobutyl decanamide application significantly reduced necrosis caused by the pathogen and inhibited fungal proliferation. Arabidopsis mutants jar1 and coi1 altered in JA signaling and a MAP kinase mutant (mpk6), unlike salicylic acid- (SA) related mutant eds16/sid2-1, were unable to defend from fungal attack even when N-isobutyl decanamide was supplied, indicating that alkamides could modulate some necrotrophic-associated defense responses through JA-dependent and MPK6-regulated signaling pathways. Our results suggest a role of alkamides in plant immunity induction. PMID:22076141

ALK F1174V mutation confers sensitivity while ALK I1171 mutation confers resistance to alectinib. The importance of serial biopsy post progression.

PubMed

Ou, Sai-Hong; Milliken, Jeffrey C; Azada, Michele C; Miller, Vincent A; Ali, Siraj M; Klempner, Samuel J

2016-01-01

Many acquired resistant mutations to the anaplastic lymphoma kinase (ALK) gene have been identified during treatment of ALK-rearranged non-small cell lung cancer (NSCLC) patients with crizotinib, ceritinib, and alectinib. These various acquired resistant ALK mutations confer differential sensitivities to various ALK inhibitors and may provide guidance on how to sequence the use of many of the second generation ALK inhibitors. We described a patient who developed an acquired ALK F1174V resistant mutation on progression from crizotinib that responded to alectinib for 18 months but then developed an acquired ALK I1171S mutation to alectinib. Both tumor samples had essentially the same genomic profile by comprehensive genomic profiling otherwise. This is the first patient report that demonstrates ALK F1174V mutation is sensitive to alectinib and further confirms missense acquired ALK I1171 mutation is resistant to alectinib. Sequential tumor re-biopsy for comprehensive genomic profiling (CGP) is important to appreciate the selective pressure during treatment with various ALK inhibitors underpinning the evolution of the disease course of ALK+NSCLC patients while on treatment with the various ALK inhibitors. This approach will likely help inform the optimal sequencing strategy as more ALK inhibitors become available. This case report also validates the importance of developing structurally distinct ALK inhibitors for clinical use to overcome non-cross resistant ALK mutations. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Experimental evolution, genetic analysis and genome re-sequencing reveal the mutation conferring artemisinin resistance in an isogenic lineage of malaria parasites

PubMed Central

2010-01-01

Background Classical and quantitative linkage analyses of genetic crosses have traditionally been used to map genes of interest, such as those conferring chloroquine or quinine resistance in malaria parasites. Next-generation sequencing technologies now present the possibility of determining genome-wide genetic variation at single base-pair resolution. Here, we combine in vivo experimental evolution, a rapid genetic strategy and whole genome re-sequencing to identify the precise genetic basis of artemisinin resistance in a lineage of the rodent malaria parasite, Plasmodium chabaudi. Such genetic markers will further the investigation of resistance and its control in natural infections of the human malaria, P. falciparum. Results A lineage of isogenic in vivo drug-selected mutant P. chabaudi parasites was investigated. By measuring the artemisinin responses of these clones, the appearance of an in vivo artemisinin resistance phenotype within the lineage was defined. The underlying genetic locus was mapped to a region of chromosome 2 by Linkage Group Selection in two different genetic crosses. Whole-genome deep coverage short-read re-sequencing (Illumina® Solexa) defined the point mutations, insertions, deletions and copy-number variations arising in the lineage. Eight point mutations arise within the mutant lineage, only one of which appears on chromosome 2. This missense mutation arises contemporaneously with artemisinin resistance and maps to a gene encoding a de-ubiquitinating enzyme. Conclusions This integrated approach facilitates the rapid identification of mutations conferring selectable phenotypes, without prior knowledge of biological and molecular mechanisms. For malaria, this model can identify candidate genes before resistant parasites are commonly observed in natural human malaria populations. PMID:20846421

A Novel Factor Xa-Inhibiting Peptide from Centipedes Venom.

PubMed

Kong, Yi; Shao, Yu; Chen, Hao; Ming, Xin; Wang, Jin-Bin; Li, Zhi-Yu; Wei, Ji-Fu

2013-01-01

Centipedes have been used as traditional medicine for thousands of years in China. Centipede venoms consist of many biochemical peptides and proteins. Factor Xa (FXa) is a serine endopeptidase that plays the key role in blood coagulation, and has been used as a new target for anti-thrombotic drug development. A novel FXa inhibitor, a natural peptide with the sequence of Thr-Asn-Gly-Tyr-Thr (TNGYT), was isolated from the venom of Scolopendra subspinipes mutilans using a combination of size-exclusion and reverse-phase chromatography. The molecular weight of the TNGYT peptide was 554.3 Da measured by electrospray ionization mass spectrometry. The amino acid sequence of TNGYT was determined by Edman degradation. TNGYT inhibited the activity of FXa in a dose-dependent manner with an IC 50 value of 41.14 mg/ml. It prolonged the partial thromboplastin time and prothrombin time in both in vitro and ex vivo assays. It also significantly prolonged whole blood clotting time and bleeding time in mice. This is the first report that an FXa inhibiting peptide was isolated from centipedes venom.

Coagulation factor Xa drives tumor cells into apoptosis through BH3-only protein Bim up-regulation

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

Borensztajn, Keren S.; Bijlsma, Maarten F.; Groot, Angelique P.

2007-07-15

Coagulation Factor (F)Xa is a serine protease that plays a crucial role during blood coagulation by converting prothrombin into active thrombin. Recently, however, it emerged that besides this role in coagulation, FXa induces intracellular signaling leading to different cellular effects. Here, we show that coagulation factor (F)Xa drives tumor cells of epithelial origin, but not endothelial cells or monocytes, into apoptosis, whereas it even enhances fibroblast survival. FXa signals through the protease activated receptor (PAR)-1 to activate extracellular-signal regulated kinase (ERK) 1/2 and p38. This activation is associated with phosphorylation of the transcription factor CREB, and in tumor cells withmore » up-regulation of the BH3-only pro-apoptotic protein Bim, leading to caspase-3 cleavage, the main hallmark of apoptosis. Transfection of tumor cells with dominant negative forms of CREB or siRNA for either PAR-1, Bim, ERK1 and/or p38 inhibited the pro-apoptotic effect of FXa. In fibroblasts, FXa-induced PAR-1 activation leads to down-regulation of Bim and pre-treatment with PAR-1 or Bim siRNA abolishes proliferation. We thus provide evidence that beyond its role in blood coagulation, FXa plays a key role in cellular processes in which Bim is the central player in determining cell survival.« less

Preclinical and Clinical Data for Factor Xa and “Universal” Reversal Agents

PubMed Central

Milling, Truman J.; Kaatz, Scott

2017-01-01

Oral Factor Xa (FXa) inhibitors, a growing class of direct-acting anticoagulants, are frequently used to prevent stroke and systemic embolism in patients with atrial fibrillation and to prevent and treat venous thromboembolism. These drugs reduce the risk of clotting at the expense of increasing the risk of bleeding, and currently they have no specific reversal agent. However, andexanet alfa, a recombinant modified FXa decoy molecule, is in a late-phase clinical trial in bleeding patients, and ciraparantag, a small molecule that appears to reverse many anticoagulants including the FXa inhibitors, is in development. This review summarizes the published data to date on both drugs, which have the potential to change the management approach to patients with FXa inhibitor–associated major hemorrhage. PMID:27575436

Difluorinated-curcumin (CDF) restores PTEN expression in colon cancer cells by down-regulating miR-21.

PubMed

Roy, Sanchita; Yu, Yingjie; Padhye, Subhash B; Sarkar, Fazlul H; Majumdar, Adhip P N

2013-01-01

Despite recent advancement in medicine, nearly 50% of patients with colorectal cancer show recurrence of the disease. Although the reasons for the high relapse are not fully understood, the presence of chemo- and radiotherapy-resistant cancer stem/stem-like cells, where many oncomirs like microRNA-21 (miR-21) are upregulated, could be one of the underlying causes. miR-21 regulates the processes of invasion and metastasis by downregulating multiple tumor/metastatic suppressor genes including PTEN (phosphatase and tensin homolog). Tumor suppressor protein PTEN controls self-renewal of stem cells. Indeed, our current data demonstrate a marked downregulation of PTEN in SCID mice xenografts of miR-21 over-expressing colon cancer HCT116 cells. Colonospheres that are highly enriched in cancer stem/stem like cells reveal increased miR-21 expression and decreased PTEN. Difluorinated curcumin (CDF), a novel analog of the dietary ingredient curcumin, which has been shown to inhibit the growth of 5-Flurouracil + Oxaliplatin resistant colon cancer cells, downregulated miR-21 in chemo-resistant colon cancer HCT116 and HT-29 cells and restored PTEN levels with subsequent reduction in Akt phosphorylation. Similar results were also observed in metastatic colon cancer SW620 cells. Since PTEN-Akt confers drug resistance to different malignancies including colorectal cancer, our observation of normalization of miR-21-PTEN-Akt pathway by CDF suggests that the compound could be a potential therapeutic agent for chemotherapy-resistant colorectal cancer.

An antibody that confers plant disease resistance targets a membrane-bound glyoxal oxidase in Fusarium.

PubMed

Song, Xiu-Shi; Xing, Shu; Li, He-Ping; Zhang, Jing-Bo; Qu, Bo; Jiang, Jin-He; Fan, Chao; Yang, Peng; Liu, Jin-Long; Hu, Zu-Quan; Xue, Sheng; Liao, Yu-Cai

2016-05-01

Plant germplasm resources with natural resistance against globally important toxigenic Fusarium are inadequate. CWP2, a Fusarium genus-specific antibody, confers durable resistance to different Fusarium pathogens that infect cereals and other crops, producing mycotoxins. However, the nature of the CWP2 target is not known. Thus, investigation of the gene coding for the CWP2 antibody target will likely provide critical insights into the mechanism underlying the resistance mediated by this disease-resistance antibody. Immunoblots and mass spectrometry analysis of two-dimensional electrophoresis gels containing cell wall proteins from Fusarium graminearum (Fg) revealed that a glyoxal oxidase (GLX) is the CWP2 antigen. Cellular localization studies showed that GLX is localized to the plasma membrane. This GLX efficiently catalyzes hydrogen peroxide production; this enzymatic activity was specifically inhibited by the CWP2 antibody. GLX-deletion strains of Fg, F. verticillioides (Fv) and F. oxysporum had significantly reduced virulence on plants. The GLX-deletion Fg and Fv strains had markedly reduced mycotoxin accumulation, and the expression of key genes in mycotoxin metabolism was downregulated. This study reveals a single gene-encoded and highly conserved cellular surface antigen that is specifically recognized by the disease-resistance antibody CWP2 and regulates both virulence and mycotoxin biosynthesis in Fusarium species. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

YODA MAP3K kinase regulates plant immune responses conferring broad-spectrum disease resistance.

PubMed

Sopeña-Torres, Sara; Jordá, Lucía; Sánchez-Rodríguez, Clara; Miedes, Eva; Escudero, Viviana; Swami, Sanjay; López, Gemma; Piślewska-Bednarek, Mariola; Lassowskat, Ines; Lee, Justin; Gu, Yangnan; Haigis, Sabine; Alexander, Danny; Pattathil, Sivakumar; Muñoz-Barrios, Antonio; Bednarek, Pawel; Somerville, Shauna; Schulze-Lefert, Paul; Hahn, Michael G; Scheel, Dierk; Molina, Antonio

2018-04-01

Mitogen-activated protein kinases (MAPKs) cascades play essential roles in plants by transducing developmental cues and environmental signals into cellular responses. Among the latter are microbe-associated molecular patterns perceived by pattern recognition receptors (PRRs), which trigger immunity. We found that YODA (YDA) - a MAPK kinase kinase regulating several Arabidopsis developmental processes, like stomatal patterning - also modulates immune responses. Resistance to pathogens is compromised in yda alleles, whereas plants expressing the constitutively active YDA (CA-YDA) protein show broad-spectrum resistance to fungi, bacteria, and oomycetes with different colonization modes. YDA functions in the same pathway as ERECTA (ER) Receptor-Like Kinase, regulating both immunity and stomatal patterning. ER-YDA-mediated immune responses act in parallel to canonical disease resistance pathways regulated by phytohormones and PRRs. CA-YDA plants exhibit altered cell-wall integrity and constitutively express defense-associated genes, including some encoding putative small secreted peptides and PRRs whose impairment resulted in enhanced susceptibility phenotypes. CA-YDA plants show strong reprogramming of their phosphoproteome, which contains protein targets distinct from described MAPKs substrates. Our results suggest that, in addition to stomata development, the ER-YDA pathway regulates an immune surveillance system conferring broad-spectrum disease resistance that is distinct from the canonical pathways mediated by described PRRs and defense hormones. © 2018 Universidad Politécnica de Madrid (UPM) New Phytologist © 2018 New Phytologist Trust.

PREFACE: XXI Fluid Mechanics Conference

NASA Astrophysics Data System (ADS)

Szmyd, Janusz S.; Fornalik-Wajs, Elzbieta; Jaszczur, Marek

2014-08-01

This Conference Volume contains the papers presented at the 21st Fluid Mechanics Conference (XXI FMC) held at AGH - University of Science and Technology in Krakow, Poland, 15-18 June 2014, and accepted for Proceedings published in the Journal of Physics: Conference Series. The Fluid Mechanics Conferences have been taking place every two years since 1974, a total of forty years. The 21st Fluid Mechanics Conference (XXI FMC) is being organized under the auspices of the Polish Academy of Sciences, Committee of Mechanics. The goal of this conference is to provide a forum for the exposure and exchange of ideas, methods and results in fluid mechanics. Conference topics include, but are not limited to Aerodynamics, Atmospheric Science, Bio-Fluids, Combustion and Reacting Flows, Computational Fluid Dynamics, Experimental Fluid Mechanics, Flow Machinery, General Fluid Dynamics, Hydromechanics, Heat and Fluid Flow, Measurement Techniques, Micro- and Nano- Flow, Multi-Phase Flow, Non-Newtonian Fluids, Rotating and Stratified Flows, Turbulence. Within the general subjects of this conference, the Professor Janusz W. Elsner Competition for the best fluid mechanics paper presented during the Conference is organized. Authors holding a M.Sc. or a Ph.D. degree and who are not older than 35 years of age may enter the Competition. Authors with a Ph.D. degree must present individual papers; authors with a M.Sc. degree may present papers with their supervisor as coauthor, including original results of experimental, numerical or analytic research. Six state-of-the-art keynote papers were delivered by world leading experts. All contributed papers were peer reviewed. Recommendations were received from the International Scientific Committee, reviewers and the advisory board. Accordingly, of the 163 eligible extended abstracts submitted, after a review process by the International Scientific Committee, 137 papers were selected for presentation at the 21st Fluid Mechanics Conference, 68

U.S.-Africa Business Conference Summary

EPA Science Inventory

The State Department, in collaboration with several co-sponsors and other US government agencies, hosted the U.S.-Africa Business Conference in Cincinnati, Ohio, June 21-22, at the Westin Cincinnati Hotel. The conference followed the annual African Growth and Opportunity Act (AGO...

Heterologous expression of a Tpo1 homolog from Arabidopsis thaliana confers resistance to the herbicide 2,4-D and other chemical stresses in yeast.

PubMed

Cabrito, Tânia R; Teixeira, Miguel C; Duarte, Alexandra A; Duque, Paula; Sá-Correia, Isabel

2009-10-01

The understanding of the molecular mechanisms underlying acquired herbicide resistance is crucial in dealing with the emergence of resistant weeds. Saccharomyces cerevisiae has been used as a model system to gain insights into the mechanisms underlying resistance to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The TPO1 gene, encoding a multidrug resistance (MDR) plasma membrane transporter of the major facilitator superfamily (MFS), was previously found to confer resistance to 2,4-D in yeast and to be transcriptionally activated in response to the herbicide. In this work, we demonstrate that Tpo1p is required to reduce the intracellular concentration of 2,4-D. ScTpo1p homologs encoding putative plasma membrane MFS transporters from the plant model Arabidopsis thaliana were analyzed for a possible role in 2,4-D resistance. At5g13750 was chosen for further analysis, as its transcript levels were found to increase in 2,4-D stressed plants. The functional heterologous expression of this plant open reading frame in yeast was found to confer increased resistance to the herbicide in Deltatpo1 and wild-type cells, through the reduction of the intracellular concentration of 2,4-D. Heterologous expression of At5g13750 in yeast also leads to increased resistance to indole-3-acetic acid (IAA), Al(3+) and Tl(3+). At5g13750 is the first plant putative MFS transporter to be suggested as possibly involved in MDR.

Molecular principles behind pyrazinamide resistance due to mutations in panD gene in Mycobacterium tuberculosis.

PubMed

Pandey, Bharati; Grover, Sonam; Tyagi, Chetna; Goyal, Sukriti; Jamal, Salma; Singh, Aditi; Kaur, Jagdeep; Grover, Abhinav

2016-04-25

The latest resurrection of drug resistance poses serious threat to the treatment and control of the disease. Mutations have been detected in panD gene in the Mycobacterium tuberculosis (Mtb) strains. Mutation of histidine to arginine at residue 21 (H21R) and isoleucine to valine at residue 29 (I49V) in the non-active site of panD gene has led to PZA resistance. This study will help in reconnoitering the mechanism of pyrazinamide (PZA) resistance caused due to double mutation identified in the panD gene of M. tuberculosis clinical isolates. It is known that panD gene encodes aspartate decarboxylase essential for β-alanine synthesis that makes it a potential therapeutic drug target for tuberculosis treatment. The knowledge about the molecular mechanism conferring drug resistance in M. tuberculosis is scarce, which is a significant challenge in designing successful therapeutic drug. In this study, structural and dynamic repercussions of H21R-I49V double mutation in panD complexed with PZA have been corroborated through docking and molecular dynamics based simulation. The double mutant (DM) shows low docking score and thus, low binding affinity for PZA as compared to the native protein. It was observed that the mutant protein exhibits more structural fluctuation at the ligand binding site in comparison to the native type. Furthermore, the flexibility and compactness analyses indicate that the double mutation influence interaction of PZA with the protein. The hydrogen-bond interaction patterns further supported our results. The covariance and PCA analysis elucidated that the double mutation affects the collective motion of residues in phase space. The results have been presented with an explanation for the induced drug resistance conferred by the H21R-I49V double mutation in panD gene and gain valuable insight to facilitate the advent of efficient therapeutics for combating resistance against PZA. Copyright © 2016 Elsevier B.V. All rights reserved.

Single 23S rRNA mutations at the ribosomal peptidyl transferase centre confer resistance to valnemulin and other antibiotics in Mycobacterium smegmatis by perturbation of the drug binding pocket.

PubMed

Long, Katherine S; Poehlsgaard, Jacob; Hansen, Lykke H; Hobbie, Sven N; Böttger, Erik C; Vester, Birte

2009-03-01

Tiamulin and valnemulin target the peptidyl transferase centre (PTC) on the bacterial ribosome. They are used in veterinary medicine to treat infections caused by a variety of bacterial pathogens, including the intestinal spirochetes Brachyspira spp. Mutations in ribosomal protein L3 and 23S rRNA have previously been associated with tiamulin resistance in Brachyspira spp. isolates, but as multiple mutations were isolated together, the roles of the individual mutations are unclear. In this work, individual 23S rRNA mutations associated with pleuromutilin resistance at positions 2055, 2447, 2504 and 2572 (Escherichia coli numbering) are introduced into a Mycobacterium smegmatis strain with a single rRNA operon. The single mutations each confer a significant and similar degree of valnemulin resistance and those at 2447 and 2504 also confer cross-resistance to other antibiotics that bind to the PTC in M. smegmatis. Antibiotic footprinting experiments on mutant ribosomes show that the introduced mutations cause structural perturbations at the PTC and reduced binding of pleuromutilin antibiotics. This work underscores the fact that mutations at nucleotides distant from the pleuromutilin binding site can confer the same level of valnemulin resistance as those at nucleotides abutting the bound drug, and suggests that the former function indirectly by altering local structure and flexibility at the drug binding pocket.

Resistant and susceptible responses in alfalfa (Medicago sativa) to bacterial stem blight caused by Pseudomonas syringae pv. syringae.

PubMed

Nemchinov, Lev G; Shao, Jonathan; Lee, Maya N; Postnikova, Olga A; Samac, Deborah A

2017-01-01

Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L). Little is known about host-pathogen interactions and host defense mechanisms. Here, individual resistant and susceptible plants were selected from cultivars Maverick and ZG9830 and used for transcript profiling at 24 and 72 hours after inoculation (hai) with the isolate PssALF3. Bioinformatic analysis revealed a number of differentially expressed genes (DEGs) in resistant and susceptible genotypes. Although resistant plants from each cultivar produced a hypersensitive response, transcriptome analyses indicated that they respond differently at the molecular level. The number of DEGs was higher in resistant plants of ZG9830 at 24 hai than in Maverick, suggesting that ZG9830 plants had a more rapid effector triggered immune response. Unique up-regulated genes in resistant ZG9830 plants included genes encoding putative nematode resistance HSPRO2-like proteins, orthologs for the rice Xa21 and soybean Rpg1-b resistance genes, and TIR-containing R genes lacking both NBS and LRR domains. The suite of R genes up-regulated in resistant Maverick plants had an over-representation of R genes in the CC-NBS-LRR family including two genes for atypical CCR domains and a putative ortholog of the Arabidopsis RPM1 gene. Resistance in both cultivars appears to be mediated primarily by WRKY family transcription factors and expression of genes involved in protein phosphorylation, regulation of transcription, defense response including synthesis of isoflavonoids, and oxidation-reduction processes. These results will further the identification of mechanisms involved in resistance to facilitate selection of parent populations and development of commercial varieties.

Resistant and susceptible responses in alfalfa (Medicago sativa) to bacterial stem blight caused by Pseudomonas syringae pv. syringae

PubMed Central

Shao, Jonathan; Lee, Maya N.; Postnikova, Olga A.; Samac, Deborah A.

2017-01-01

Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L). Little is known about host-pathogen interactions and host defense mechanisms. Here, individual resistant and susceptible plants were selected from cultivars Maverick and ZG9830 and used for transcript profiling at 24 and 72 hours after inoculation (hai) with the isolate PssALF3. Bioinformatic analysis revealed a number of differentially expressed genes (DEGs) in resistant and susceptible genotypes. Although resistant plants from each cultivar produced a hypersensitive response, transcriptome analyses indicated that they respond differently at the molecular level. The number of DEGs was higher in resistant plants of ZG9830 at 24 hai than in Maverick, suggesting that ZG9830 plants had a more rapid effector triggered immune response. Unique up-regulated genes in resistant ZG9830 plants included genes encoding putative nematode resistance HSPRO2-like proteins, orthologs for the rice Xa21 and soybean Rpg1-b resistance genes, and TIR-containing R genes lacking both NBS and LRR domains. The suite of R genes up-regulated in resistant Maverick plants had an over-representation of R genes in the CC-NBS-LRR family including two genes for atypical CCR domains and a putative ortholog of the Arabidopsis RPM1 gene. Resistance in both cultivars appears to be mediated primarily by WRKY family transcription factors and expression of genes involved in protein phosphorylation, regulation of transcription, defense response including synthesis of isoflavonoids, and oxidation-reduction processes. These results will further the identification of mechanisms involved in resistance to facilitate selection of parent populations and development of commercial varieties. PMID:29244864

Transgenic tobacco expressing Pinellia ternata agglutinin confers enhanced resistance to aphids.

PubMed

Yao, Jianhong; Pang, Yongzhen; Qi, Huaxiong; Wan, Bingliang; Zhao, Xiuyun; Kong, Weiwen; Sun, Xiaofen; Tang, Kexuan

2003-12-01

Tobacco leaf discs were transformed with a plasmid, pBIPTA, containing the selectable marker neomycin phosphotransferase gene (nptII) and Pinellia ternata agglutinin gene (pta) via Agrobacterium tumefaciens-mediated transformation. Thirty-two independent transgenic tobacco plants were regenerated. PCR and Southern blot analyses confirmed that the pta gene had integrated into the plant genome and northern blot analysis revealed transgene expression at various levels in transgenic plants. Genetic analysis confirmed Mendelian segregation of the transgene in T1 progeny. Insect bioassays showed that transgenic plants expressing PTA inhibited significantly the growth of peach potato aphid (Myzus persicae Sulzer). This is the first report that transgenic plants expressing pta confer enhanced resistance to aphids. Our study indicates that the pta gene can be used as a supplement to the snowdrop (Galanthus nivalis) lectin gene (gna) in the control of aphids, a sap-sucking insect pest causing significant yield losses of crops.

Identification and Characterization of Mutations Conferring Resistance to d-Amino Acids in Bacillus subtilis

PubMed Central

Leiman, Sara A.; Richardson, Charles; Foulston, Lucy; Elsholz, Alexander K. W.; First, Eric A.

2015-01-01

ABSTRACT Bacteria produce d-amino acids for incorporation into the peptidoglycan and certain nonribosomally produced peptides. However, d-amino acids are toxic if mischarged on tRNAs or misincorporated into protein. Common strains of the Gram-positive bacterium Bacillus subtilis are particularly sensitive to the growth-inhibitory effects of d-tyrosine due to the absence of d-aminoacyl-tRNA deacylase, an enzyme that prevents misincorporation of d-tyrosine and other d-amino acids into nascent proteins. We isolated spontaneous mutants of B. subtilis that survive in the presence of a mixture of d-leucine, d-methionine, d-tryptophan, and d-tyrosine. Whole-genome sequencing revealed that these strains harbored mutations affecting tRNATyr charging. Three of the most potent mutations enhanced the expression of the gene (tyrS) for tyrosyl-tRNA synthetase. In particular, resistance was conferred by mutations that destabilized the terminator hairpin of the tyrS riboswitch, as well as by a mutation that transformed a tRNAPhe into a tyrS riboswitch ligand. The most potent mutation, a substitution near the tyrosine recognition site of tyrosyl-tRNA synthetase, improved enzyme stereoselectivity. We conclude that these mutations promote the proper charging of tRNATyr, thus facilitating the exclusion of d-tyrosine from protein biosynthesis in cells that lack d-aminoacyl-tRNA deacylase. IMPORTANCE Proteins are composed of l-amino acids. Mischarging of tRNAs with d-amino acids or the misincorporation of d-amino acids into proteins causes toxicity. This work reports on mutations that confer resistance to d-amino acids and their mechanisms of action. PMID:25733611

Direct thrombin and factor Xa inhibition for stroke prevention in patients with atrial fibrillation.

PubMed

Galanis, Taki; Merli, Geno J

2013-02-01

Nonvalvular atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia occurring in patients in the United States. The primary clinical consequence of AF is an increase in the risk and severity of strokes. Treatment guidelines recommend anticoagulation therapy for most patients with AF. One risk-stratification scheme, the CHADS2 index, is simple and widely used to determine the management of patients with AF in regard to stroke prevention. However, new schemes, such as CHA2DS2-VASc, further refine risk stratification to identify patients who would obtain a net clinical benefit from a particular management strategy, thus improving the quality of management. For patients with AF for whom oral anticoagulation (OAC) is advisable, vitamin K antagonist (VKA) therapy is well established and effective. However, OAC with VKAs presents challenges to prescribers and patients in maintaining therapeutic efficacy. Novel OACs may offer alternatives to VKAs. Dabigatran etexilate, a direct thrombin inhibitor, was approved by the US Food and Drug Administration (FDA) in 2010 for reducing the risk of stroke and systemic embolism in patients with nonvalvular AF. The activated factor X (factor Xa) inhibitor rivaroxaban was recently approved by the FDA both for prophylaxis of deep vein thrombosis, which may lead to pulmonary embolism in patients undergoing knee or hip arthroplasty, and for reducing the risk of stroke and systemic embolism in patients with nonvalvular AF. Apixaban, another factor Xa inhibitor, was recently shown to be effective for stroke prevention in patients with nonvalvular AF. This article reviews clinical considerations regarding new agents that may offer alternatives to VKA therapy for the prevention of stroke in patients with AF.

Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on e-Learning (Las Palmas de Gran Canaria, Spain, July 21-24, 2015)

ERIC Educational Resources Information Center

Nunes, Miguel Baptista, Ed.; McPherson, Maggie, Ed.

2015-01-01

These proceedings contain the papers of the International Conference e-Learning 2015, which was organised by the International Association for Development of the Information and Society and is part of the Multi Conference on Computer Science and Information Systems (Las Palmas de Gran Canaria, Spain, July 21-24, 2015). The e-Learning 2015…

Identification of regulated genes conferring resistance to high concentrations of glyphosate in a new strain of Enterobacter.

PubMed

Fei, Yun-Yan; Gai, Jun-Yi; Zhao, Tuan-Jie

2013-12-01

Glyphosate is a widely used herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity. Most plants and microbes are sensitive to glyphosate. However, transgenic-resistant crops that contain a modified epsps obtained from the resistant microbes have been commercially successful and therefore, new resistance genes and their adaptive regulatory mechanisms are of great interest. In this study, a soil-borne, glyphosate-resistant bacterium was selected and identified as Enterobacter. The EPSPS in this strain was found to have been altered to a resistant one. A total of 42 differentially expressed genes (DEGs) in the glyphosate were screened using microarray techniques. Under treatment, argF, sdhA, ivbL, rrfA-H were downregulated, whereas the transcripts of speA, osmY, pflB, ahpC, fusA, deoA, uxaC, rpoD and a few ribosomal protein genes were upregulated. Data were verified by quantitative real-time PCR on selected genes. All transcriptional changes appeared to protect the bacteria from glyphosate and associated osmotic, acidic and oxidative stresses. Many DEGs may have the potential to confer resistance to glyphosate alone, and some may be closely related to the shikimate pathway, reflecting the complex gene interaction network for glyphosate resistance. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Increased Tuberculosis Patient Mortality Associated with Mycobacterium tuberculosis Mutations Conferring Resistance to Second-Line Antituberculous Drugs

PubMed Central

Seifert, Marva; Garfein, Richard S.; Rodwell, Timothy C.

2017-01-01

ABSTRACT Rapid molecular diagnostics have great potential to limit the spread of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) (M/XDR-TB). These technologies detect mutations in the Mycobacterium tuberculosis genome that confer phenotypic drug resistance. However, there have been few data published regarding the relationships between the detected M. tuberculosis resistance mutations and M/XDR-TB treatment outcomes, limiting our current ability to exploit the full potential of molecular diagnostics. We analyzed clinical, microbiological, and sequencing data for 451 patients and their clinical isolates collected in a multinational, observational cohort study to determine if there was an association between M. tuberculosis resistance mutations and patient mortality. The presence of an rrs 1401G mutation was associated with significantly higher odds of patient mortality (adjusted odds ratio [OR] = 5.72; 95% confidence interval [CI], 1.65 to 19.84]) after adjusting for relevant patient clinical characteristics and all other resistance mutations. Further analysis of mutations, categorized by the associated resistance level, indicated that the detection of mutations associated with high-level fluoroquinolone (OR, 3.99 [95% CI, 1.10 to 14.40]) and kanamycin (OR, 5.47 [95% CI, 1.64 to 18.24]) resistance was also significantly associated with higher odds of patient mortality, even after accounting for clinical site, patient age, reported smoking history, body mass index (BMI), diabetes, HIV, and all other resistance mutations. Specific gyrA and rrs resistance mutations, associated with high-level resistance, were associated with patient mortality as identified in clinical M. tuberculosis isolates from a diverse M/XDR-TB patient population at three high-burden clinical sites. These results have important implications for the interpretation of molecular diagnostics, including identifying patients at increased risk for mortality

Increased Tuberculosis Patient Mortality Associated with Mycobacterium tuberculosis Mutations Conferring Resistance to Second-Line Antituberculous Drugs.

PubMed

Georghiou, Sophia B; Seifert, Marva; Catanzaro, Donald G; Garfein, Richard S; Rodwell, Timothy C

2017-06-01

Rapid molecular diagnostics have great potential to limit the spread of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) (M/XDR-TB). These technologies detect mutations in the Mycobacterium tuberculosis genome that confer phenotypic drug resistance. However, there have been few data published regarding the relationships between the detected M. tuberculosis resistance mutations and M/XDR-TB treatment outcomes, limiting our current ability to exploit the full potential of molecular diagnostics. We analyzed clinical, microbiological, and sequencing data for 451 patients and their clinical isolates collected in a multinational, observational cohort study to determine if there was an association between M. tuberculosis resistance mutations and patient mortality. The presence of an rrs 1401G mutation was associated with significantly higher odds of patient mortality (adjusted odds ratio [OR] = 5.72; 95% confidence interval [CI], 1.65 to 19.84]) after adjusting for relevant patient clinical characteristics and all other resistance mutations. Further analysis of mutations, categorized by the associated resistance level, indicated that the detection of mutations associated with high-level fluoroquinolone (OR, 3.99 [95% CI, 1.10 to 14.40]) and kanamycin (OR, 5.47 [95% CI, 1.64 to 18.24]) resistance was also significantly associated with higher odds of patient mortality, even after accounting for clinical site, patient age, reported smoking history, body mass index (BMI), diabetes, HIV, and all other resistance mutations. Specific gyrA and rrs resistance mutations, associated with high-level resistance, were associated with patient mortality as identified in clinical M. tuberculosis isolates from a diverse M/XDR-TB patient population at three high-burden clinical sites. These results have important implications for the interpretation of molecular diagnostics, including identifying patients at increased risk for mortality during

An independent occurrence of the chimeric P450 enzyme CYP337B3 of Helicoverpa armigera confers cypermethrin resistance in Pakistan.

PubMed

Rasool, Akhtar; Joußen, Nicole; Lorenz, Sybille; Ellinger, Renate; Schneider, Bernd; Khan, Sher Afzal; Ashfaq, Muhammad; Heckel, David G

2014-10-01

The increasing resistance level of insect pest species is a major concern to agriculture worldwide. The cotton bollworm, Helicoverpa armigera, is one of the most important pest species due to being highly polyphagous, geographically widespread, and resistant towards many chemical classes of insecticides. We previously described the mechanism of fenvalerate resistance in Australian populations conferred by the chimeric cytochrome P450 monooxygenase CYP337B3, which arose by unequal crossing-over between CYP337B1 and CYP337B2. Here, we show that this mechanism is also present in the cypermethrin-resistant FSD strain from Pakistan. The Pakistani and the Australian CYP337B3 alleles differ by 18 synonymous and three nonsynonymous SNPs and additionally in the length and sequence of the intron. Nevertheless, the activity of both CYP337B3 proteins is comparable. We demonstrate that CYP337B3 is capable of metabolizing cypermethrin (trans- and especially cis-isomers) to the main metabolite 4'-hydroxycypermethrin, which exhibits no intrinsic toxicity towards susceptible larvae. In a bioassay, CYP337B3 confers a 7-fold resistance towards cypermethrin in FSD larvae compared to susceptible larvae from the Australian TWB strain lacking CYP337B3. Linkage analysis shows that presence of CYP337B3 accounts for most of the cypermethrin resistance in the FSD strain; up-regulation of other P450s in FSD plays no detectable role in resistance. The presence or absence of CYP337B3 can be easily detected by a simple PCR screen, providing a powerful tool to rapidly distinguish resistant from susceptible individuals in the field and to determine the geographical distribution of this resistance gene. Our results suggest that CYP337B3 evolved twice independently by unequal crossing-over between CYP337B2 and two different CYP337B1 alleles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fibroblast growth factor-21 restores insulin sensitivity but induces aberrant bone microstructure in obese insulin-resistant rats.

PubMed

Charoenphandhu, Narattaphol; Suntornsaratoon, Panan; Krishnamra, Nateetip; Sa-Nguanmoo, Piangkwan; Tanajak, Pongpun; Wang, Xiaojie; Liang, Guang; Li, Xiaokun; Jiang, Chao; Chattipakorn, Nipon; Chattipakorn, Siriporn

2017-03-01

Fibroblast growth factor (FGF)-21 is a potent endocrine factor that improves insulin resistance and obesity-associated metabolic disorders. However, concomitant activation of peroxisome proliferator-activated receptor-γ by FGF-21 makes bone susceptible to osteopenia and fragility fracture. Since an increase in body weight often induced adaptive change in bone by making it resistant to fracture, it was unclear whether FGF-21 would still induce bone defects in overweight rats. Therefore, the present study aimed to investigate bone microstructure and its mechanical properties in high fat diet (HF)-fed rats treated with 0.1 mg/kg/day FGF-21. Eighteen male rats were divided into two groups to receive either a normal diet or HF for 12 weeks. HF rats were then divided into two subgroups to receive either vehicle or FGF-21 for 4 weeks. The results showed that HF led to obesity, dyslipidemia and insulin resistance, as indicated by hyperinsulinemia with euglycemia. In HF rats, there was an increase in tibial yield displacement (an indicator of ability to be deformed without losing toughness, as determined by 3-point bending) without changes in tibial trabecular volumetric bone mineral density (vBMD) or cortical bone parameters, e.g., cortical thickness and bone area. FGF-21 treatment strongly improved the metabolic parameters and increased insulin sensitivity in HF rats. However, FGF-21-treated HF rats showed lower yield displacement, trabecular vBMD, trabecular bone volume, trabecular thickness, and osteoblast surface compared with vehicle-treated HF rats. These findings suggest that, despite being a potent antagonist of insulin resistance and visceral fat accumulation, FGF-21 is associated with bone defects in HF rats.

Diaminopurine-Resistant Mutants of Cultured, Diploid Human Fibroblasts

PubMed Central

Rappaport, Harriet; DeMars, Robert

1973-01-01

Clones of cells resistant to 2,6-diaminopurine were detected in skin fibroblast cultures derived from 13 of 21 normal humans of both sexes from 17 unrelated families. Almost all of the cultures that yielded mutants were chosen for further study from among a total of 83 surveyed because they displayed a slight resistance to low concentrations of diaminopurine. The incidences of mutant colonies ranged between about 10-5 and 10-4 per cell surviving prior mutagenic treatment with MNNG. The incidences of spontaneous mutants were about 10-7 to 10-5 in three unrelated cultures. Most independent mutants had distinctly reduced activity of adenine phosphoribosyltransferase but some had apparently normal amounts of activity. Two mutants from unrelated boys had little or no detectable enzyme activity and were unable to effectively use exogenous adenine for growth when purine biosynthesis was blocked with azaserine. Most mutants could utilize exogenous adenine, just as most azaguanine-resistant fibroblast mutants can utilize exogenous hypoxanthine, even when their hypoxanthine-guanine phosphoribosyltransferase activity is reduced. Diverse genetic changes conferred diaminopurine resistance but their specific natures are still undefined. Gross numerical or structural chromosome abnormalities were not observed in the mutants examined so far. Since at least one gene responsible for adenine phosphoribosyltransferase activity is on autosome No. 16 our results suggest that at least some of the cultures yielding mutants were heterozygous and that alleles conferring diaminopurine resistance may be frequent enough to comprise a polymorphism. PMID:4358687

21 CFR 700.25 - Tamper-resistant packaging requirements for cosmetic products.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Tamper-resistant packaging requirements for cosmetic products. 700.25 Section 700.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... of cosmetic product packages. The Food and Drug Administration has the authority and responsibility...

21 CFR 866.3950 - In vitro human immunodeficiency virus (HIV) drug resistance genotype assay.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false In vitro human immunodeficiency virus (HIV) drug... Serological Reagents § 866.3950 In vitro human immunodeficiency virus (HIV) drug resistance genotype assay. (a) Identification. The in vitro HIV drug resistance genotype assay is a device that consists of nucleic acid reagent...

21 CFR 866.3950 - In vitro human immunodeficiency virus (HIV) drug resistance genotype assay.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false In vitro human immunodeficiency virus (HIV) drug... Serological Reagents § 866.3950 In vitro human immunodeficiency virus (HIV) drug resistance genotype assay. (a) Identification. The in vitro HIV drug resistance genotype assay is a device that consists of nucleic acid reagent...

21 CFR 866.3950 - In vitro human immunodeficiency virus (HIV) drug resistance genotype assay.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false In vitro human immunodeficiency virus (HIV) drug... Serological Reagents § 866.3950 In vitro human immunodeficiency virus (HIV) drug resistance genotype assay. (a) Identification. The in vitro HIV drug resistance genotype assay is a device that consists of nucleic acid reagent...

21 CFR 866.3950 - In vitro human immunodeficiency virus (HIV) drug resistance genotype assay.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false In vitro human immunodeficiency virus (HIV) drug... Serological Reagents § 866.3950 In vitro human immunodeficiency virus (HIV) drug resistance genotype assay. (a) Identification. The in vitro HIV drug resistance genotype assay is a device that consists of nucleic acid reagent...

21 CFR 866.3950 - In vitro human immunodeficiency virus (HIV) drug resistance genotype assay.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false In vitro human immunodeficiency virus (HIV) drug... Serological Reagents § 866.3950 In vitro human immunodeficiency virus (HIV) drug resistance genotype assay. (a) Identification. The in vitro HIV drug resistance genotype assay is a device that consists of nucleic acid reagent...

Resistance to hypoxia-induced necroptosis is conferred by glycolytic pyruvate scavenging of mitochondrial superoxide in colorectal cancer cells.

PubMed

Huang, C-Y; Kuo, W-T; Huang, Y-C; Lee, T-C; Yu, L C H

2013-05-02

Cancer cells may survive under oxygen and nutrient deprivation by metabolic reprogramming for high levels of anaerobic glycolysis, which contributes to tumor growth and drug resistance. Abnormally expressed glucose transporters (GLUTs) are colocalized with hypoxia (Hx) inducible factor (HIF)1α in peri-necrotic regions in human colorectal carcinoma. However, the underlying mechanisms of anti-necrotic resistance conferred by glucose metabolism in hypoxic cancer cells remain poorly understood. Our aim was to investigate signaling pathways of Hx-induced necroptosis and explore the role of glucose pyruvate metabolite in mechanisms of death resistance. Human colorectal carcinoma cells were Hx exposed with or without glucose, and cell necroptosis was examined by receptor-interacting protein (RIP)1/3 kinase immunoprecipitation and (32)P kinase assays. Our results showed increased RIP1/3 complex formation and phosphorylation in hypoxic, but not normoxic cells in glucose-free media. Blocking RIP1 signaling, by necrostatin-1 or gene silencing, decreased lactodehydrogenase (LDH) leakage and plasma membrane disintegration. Generation of mitochondrial superoxide was noted after hypoxic challenge; its reduction by antioxidants inhibited RIP signaling and cell necrosis. Supplementation of glucose diminished the RIP-dependent LDH leakage and morphological damage in hypoxic cells, whereas non-metabolizable sugar analogs did not. Hypoxic cells given glucose showed nuclear translocation of HIF1α associated with upregulation of GLUT-1 and GLUT-4 expression, as well as increase of intracellular ATP, pyruvate and lactate levels. The glucose-mediated death resistance was ablated by iodoacetate (an inhibitor to glyceraldehyde-3-phosphate dehydrogenase), but not by UK5099 (an inhibitor to mitochondrial pyruvate carrier), suggesting that glycolytic pathway was involved in anti-necrotic mechanism. Lastly, replacing glucose with cell-permeable pyruvate derivative also led to decrease of Hx

Molecular Characterization of a Chromosomal Determinant Conferring Resistance to Zinc and Cobalt Ions in Staphylococcus aureus

PubMed Central

Xiong, Anming; Jayaswal, Radheshyam K.

1998-01-01

A DNA fragment conferring resistance to zinc and cobalt ions was isolated from a genomic DNA library of Staphylococcus aureus RN450. The DNA sequence analysis revealed two consecutive open reading frames, designated zntR and zntA. The predicted ZntR and ZntA showed significant homology to members of ArsR and cation diffusion families, respectively. A mutant strain containing the null allele of zntA was more sensitive to zinc and cobalt ions than was the parent strain. The metal-sensitive phenotype of the mutant was complemented by a 2.9-kb DNA fragment containing zntR and zntA. An S. aureus strain harboring multiple copies of zntR and zntA showed an increased resistance to zinc. The resistance to zinc in the wild-type strain was inducible. Transcriptional analysis indicated that zntR and zntA genes were cotranscribed. The zinc uptake studies suggested that the zntA product was involved in the export of zinc ions out of cells. PMID:9696746

Vision 2000 Conference Report (Alexandria, Virginia, July 21-24, 1994).

ERIC Educational Resources Information Center

National Council for Agricultural Education, Alexandria, VA.

Representatives of 11 organizations playing a leading role in agricultural education (AE) attended a conference to discuss their vision of AE in the year 2000. During the conference, the issues of greatest concern to AE were prioritized, specific strategies/solutions to accomplish each priority were identified, an action plan to achieve desired…

Can Ceftazidime-Avibactam and Aztreonam Overcome β-Lactam Resistance Conferred by Metallo-β-Lactamases in Enterobacteriaceae?

PubMed

Marshall, Steven; Hujer, Andrea M; Rojas, Laura J; Papp-Wallace, Krisztina M; Humphries, Romney M; Spellberg, Brad; Hujer, Kristine M; Marshall, Emma K; Rudin, Susan D; Perez, Federico; Wilson, Brigid M; Wasserman, Ronald B; Chikowski, Linda; Paterson, David L; Vila, Alejandro J; van Duin, David; Kreiswirth, Barry N; Chambers, Henry F; Fowler, Vance G; Jacobs, Michael R; Pulse, Mark E; Weiss, William J; Bonomo, Robert A

2017-04-01

Based upon knowledge of the hydrolytic profile of major β-lactamases found in Gram-negative bacteria, we tested the efficacy of the combination of ceftazidime-avibactam (CAZ-AVI) with aztreonam (ATM) against carbapenem-resistant enteric bacteria possessing metallo-β-lactamases (MBLs). Disk diffusion and agar-based antimicrobial susceptibility testing were initially performed to determine the in vitro efficacy of a unique combination of CAZ-AVI and ATM against 21 representative Enterobacteriaceae isolates with a complex molecular background that included bla IMP , bla NDM , bla OXA-48 , bla CTX-M , bla AmpC , and combinations thereof. Time-kill assays were conducted, and the in vivo efficacy of this combination was assessed in a murine neutropenic thigh infection model. By disk diffusion assay, all 21 isolates were resistant to CAZ-AVI alone, and 19/21 were resistant to ATM. The in vitro activity of CAZ-AVI in combination with ATM against diverse Enterobacteriaceae possessing MBLs was demonstrated in 17/21 isolates, where the zone of inhibition was ≥21 mm. All isolates demonstrated a reduction in CAZ-AVI agar dilution MICs with the addition of ATM. At 2 h, time-kill assays demonstrated a ≥4-log 10 -CFU decrease for all groups that had CAZ-AVI with ATM (8 μg/ml) added, compared to the group treated with CAZ-AVI alone. In the murine neutropenic thigh infection model, an almost 4-log 10 -CFU reduction was noted at 24 h for CAZ-AVI (32 mg/kg every 8 h [q8h]) plus ATM (32 mg/kg q8h) versus CAZ-AVI (32 mg/kg q8h) alone. The data presented herein require us to carefully consider this new therapeutic combination to treat infections caused by MBL-producing Enterobacteriaceae . Copyright © 2017 American Society for Microbiology.

Changing Paradigms in Down Syndrome: The First International Conference of the Trisomy 21 Research Society.

PubMed

Delabar, Jean-Maurice; Allinquant, Bernadette; Bianchi, Diana; Blumenthal, Tom; Dekker, Alain; Edgin, Jamie; O'Bryan, John; Dierssen, Mara; Potier, Marie-Claude; Wiseman, Frances; Guedj, Faycal; Créau, Nicole; Reeves, Roger; Gardiner, Katheleen; Busciglio, Jorge

2016-10-01

Down syndrome (DS) is the most common genetic cause of intellectual disability (ID) in humans with an incidence of ∼1:1,000 live births worldwide. It is caused by the presence of an extra copy of all or a segment of the long arm of human chromosome 21 (trisomy 21). People with DS present with a constellation of phenotypic alterations involving most organs and organ systems. ID is present in all people with DS, albeit with variable severity. DS is also the most frequent genetic cause of Alzheimer's disease (AD), and ∼50% of those with DS will develop AD-related dementia. In the last few years, significant progress has been made in understanding the crucial genotype-phenotype relationships in DS, in identifying the alterations in molecular pathways leading to the various clinical conditions present in DS, and in preclinical evaluations of potential therapies to improve the overall health and well-being of individuals with DS. In June 2015, 230 scientists, advocates, patients, and family members met in Paris for the 1st International Conference of the Trisomy 21 Research Society. Here, we report some of the most relevant presentations that took place during the meeting.

Dietary resveratrol confers apoptotic resistance to oxidative stress in myoblasts.

PubMed

Haramizu, Satoshi; Asano, Shinichi; Butler, David C; Stanton, David A; Hajira, Ameena; Mohamed, Junaith S; Alway, Stephen E

2017-12-01

High levels of reactive oxygen species (ROS) contribute to muscle cell death in aging and disuse. We have previously found that resveratrol can reduce oxidative stress in response to aging and hindlimb unloading in rodents in vivo, but it was not known if resveratrol would protect muscle stem cells during repair or regeneration when oxidative stress is high. To test the protective role of resveratrol on muscle stem cells directly, we treated the C2C12 mouse myoblast cell line with moderate (100 μM) or very high (1 mM) levels of H 2 O 2 in the presence or absence of resveratrol. The p21 promoter activity declined in myoblasts in response to high ROS, and this was accompanied a greater nuclear to cytoplasmic translocation of p21 in a dose-dependent matter in myoblasts as compared to myotubes. Apoptosis, as indicated by TdT-mediated dUTP nick-end labeling, was greater in C2C12 myoblasts as compared to myotubes (P<.05) after treatment with H 2 O 2 . Caspase-9, -8 and -3 activities were elevated significantly (P<.05) in myoblasts treated with H 2 O 2 . Myoblasts were more susceptible to ROS-induced oxidative stress than myotubes. We treated C2C12 myoblasts with 50 μM of resveratrol for periods up to 48 h to determine if myoblasts could be rescued from high-ROS-induced apoptosis by resveratrol. Resveratrol reduced the apoptotic index and significantly reduced the ROS-induced caspase-9, -8 and -3 activity in myoblasts. Furthermore, Bcl-2 and the Bax/Bcl-2 ratio were partially rescued in myoblasts by resveratrol treatment. Similarly, muscle stem cells isolated from mouse skeletal muscles showed reduced Sirt1 protein abundance with H 2 O 2 treatment, but this could be reversed by resveratrol. Reduced apoptotic susceptibility in myoblasts as compared to myotubes to ROS is regulated, at least in part, by enhanced p21 promoter activity and nuclear p21 location in myotubes. Resveratrol confers further protection against ROS by improving Sirt1 levels and increasing antioxidant

Our Stories: Innovation and Excellence in Rural Education. Proceedings of National Rural Education Conference of the Society for the Provision of Education in Rural Australia (21st, Darwin, Northern Territory, Australia, October 2005)

ERIC Educational Resources Information Center

Boylan, Colin, Ed.

2005-01-01

The papers contained in this document represent the keynote addresses, refereed and non-refereed conference papers from the 21st National Conference of the Society for the Provision of Education in Rural Australia (SPERA). The theme for this national annual conference was: Our Stories: Innovation and Excellence in Rural Education. Keynote…

Geographical gradient of the eIF4E alleles conferring resistance to potyviruses in pea (Pisum) germplasm.

PubMed

Konečná, Eva; Šafářová, Dana; Navrátil, Milan; Hanáček, Pavel; Coyne, Clarice; Flavell, Andrew; Vishnyakova, Margarita; Ambrose, Mike; Redden, Robert; Smýkal, Petr

2014-01-01

The eukaryotic translation initiation factor 4E was shown to be involved in resistance against several potyviruses in plants, including pea. We combined our knowledge of pea germplasm diversity with that of the eIF4E gene to identify novel genetic diversity. Germplasm of 2803 pea accessions was screened for eIF4E intron 3 length polymorphism, resulting in the detection of four eIF4E(A-B-C-S) variants, whose distribution was geographically structured. The eIF4E(A) variant conferring resistance to the P1 PSbMV pathotype was found in 53 accessions (1.9%), of which 15 were landraces from India, Afghanistan, Nepal, and 7 were from Ethiopia. A newly discovered variant, eIF4E(B), was present in 328 accessions (11.7%) from Ethiopia (29%), Afghanistan (23%), India (20%), Israel (25%) and China (39%). The eIF4E(C) variant was detected in 91 accessions (3.2% of total) from India (20%), Afghanistan (33%), the Iberian Peninsula (22%) and the Balkans (9.3%). The eIF4E(S) variant for susceptibility predominated as the wild type. Sequencing of 73 samples, identified 34 alleles at the whole gene, 26 at cDNA and 19 protein variants, respectively. Fifteen alleles were virologically tested and 9 alleles (eIF4E(A-1-2-3-4-5-6-7), eIF4E(B-1), eIF4E(C-2)) conferred resistance to the P1 PSbMV pathotype. This work identified novel eIF4E alleles within geographically structured pea germplasm and indicated their independent evolution from the susceptible eIF4E(S1) allele. Despite high variation present in wild Pisum accessions, none of them possessed resistance alleles, supporting a hypothesis of distinct mode of evolution of resistance in wild as opposed to crop species. The Highlands of Central Asia, the northern regions of the Indian subcontinent, Eastern Africa and China were identified as important centers of pea diversity that correspond with the diversity of the pathogen. The series of alleles identified in this study provides the basis to study the co-evolution of potyviruses and the

Geographical Gradient of the eIF4E Alleles Conferring Resistance to Potyviruses in Pea (Pisum) Germplasm

PubMed Central

Konečná, Eva; Šafářová, Dana; Navrátil, Milan; Hanáček, Pavel; Coyne, Clarice; Flavell, Andrew; Vishnyakova, Margarita; Ambrose, Mike; Redden, Robert; Smýkal, Petr

2014-01-01

Background The eukaryotic translation initiation factor 4E was shown to be involved in resistance against several potyviruses in plants, including pea. We combined our knowledge of pea germplasm diversity with that of the eIF4E gene to identify novel genetic diversity. Methodology/Principal findings Germplasm of 2803 pea accessions was screened for eIF4E intron 3 length polymorphism, resulting in the detection of four eIF4EA-B-C-S variants, whose distribution was geographically structured. The eIF4EA variant conferring resistance to the P1 PSbMV pathotype was found in 53 accessions (1.9%), of which 15 were landraces from India, Afghanistan, Nepal, and 7 were from Ethiopia. A newly discovered variant, eIF4EB, was present in 328 accessions (11.7%) from Ethiopia (29%), Afghanistan (23%), India (20%), Israel (25%) and China (39%). The eIF4EC variant was detected in 91 accessions (3.2% of total) from India (20%), Afghanistan (33%), the Iberian Peninsula (22%) and the Balkans (9.3%). The eIF4ES variant for susceptibility predominated as the wild type. Sequencing of 73 samples, identified 34 alleles at the whole gene, 26 at cDNA and 19 protein variants, respectively. Fifteen alleles were virologically tested and 9 alleles (eIF4EA-1-2-3-4-5-6-7, eIF4EB-1, eIF4EC-2) conferred resistance to the P1 PSbMV pathotype. Conclusions/Significance This work identified novel eIF4E alleles within geographically structured pea germplasm and indicated their independent evolution from the susceptible eIF4ES1 allele. Despite high variation present in wild Pisum accessions, none of them possessed resistance alleles, supporting a hypothesis of distinct mode of evolution of resistance in wild as opposed to crop species. The Highlands of Central Asia, the northern regions of the Indian subcontinent, Eastern Africa and China were identified as important centers of pea diversity that correspond with the diversity of the pathogen. The series of alleles identified in this study provides the basis

An unusual Tn21-like transposon containing an ars operon is present in highly arsenic-resistant strains of the biomining bacterium Acidithiobacillus caldus.

PubMed

Tuffin, I Marla; de Groot, Peter; Deane, Shelly M; Rawlings, Douglas E

2005-09-01

A transposon, TnAtcArs, that carries a set of arsenic-resistance genes was isolated from a strain of the moderately thermophilic, sulfur-oxidizing, biomining bacterium Acidithiobacillus caldus. This strain originated from a commercial plant used for the bio-oxidation of gold-bearing arsenopyrite concentrates. Continuous selection for arsenic resistance over many years had made the bacterium resistant to high concentrations of arsenic. Sequence analysis indicated that TnAtcArs is 12 444 bp in length and has 40 bp terminal inverted repeat sequences and divergently transcribed resolvase and transposase genes that are related to the Tn21-transposon subfamily. A series of genes consisting of arsR, two tandem copies of arsA and arsD, two ORFs (7 and 8) and arsB is situated between the resolvase and transposase genes. Although some commercial strains of At. caldus contained the arsDA duplication, when transformed into Escherichia coli, the arsDA duplication was unstable and was frequently lost during cultivation or if a plasmid containing TnAtcArs was conjugated into a recipient strain. TnAtcArs conferred resistance to arsenite and arsenate upon E. coli cells. Deletion of one copy of arsDA had no noticeable effect on resistance to arsenite or arsenate in E. coli. ORFs 7 and 8 had clear sequence similarity to an NADH oxidase and a CBS-domain-containing protein, respectively, but their deletion did not affect resistance to arsenite or arsenate in E. coli. TnAtcArs was actively transposed in E. coli, but no increase in transposition frequency in the presence of arsenic was detected. Northern hybridization and reporter gene studies indicated that although ArsR regulated the 10 kb operon containing the arsenic-resistance genes in response to arsenic, ArsR had no effect on the regulation of genes associated with transposition activity.

Inheritance of resistance to the bean-pod weevil (Apion godmani Wagner) in common beans from Mexico.

PubMed

Garza, R; Cardona, C; Singh, S P

1996-03-01

The bean-pod weevil (BPW), Apion godmani Wagner, often causes heavy losses in crops of common bean (Phaseolus vulgaris L.). Farmers need resistant bean cultivars to minimize losses, cut production costs, stabilize seed yield, and reduce pesticide use and consequent health hazards. To design effective breeding methods, breeders need new and better sources of resistance and increased knowledge of their modes of inheritance. We therefore: (1) compared sources of resistance to BPW, (2) studied the inheritance of resistance, and (3) determined whether the sources possess similar or different genes for BPW resistance. The following sources of resistance, originating from the Mexican highlands, were evaluated for 3 years at INIFAP-Santa Lucía de Prias, Texcoco, Mexico: 'Amarillo 153', 'Amarillo 169', 'Hidalgo 58', 'J 117', 'Pinto Texcoco', 'Pinto 168', and 'Puebla 36'. All except 'Puebla 36' were crossed with the susceptible cultivar 'Jamapa'. 'Amarillo 153' and 'Puebla 36' were crossed with another susceptible cultivar, 'Bayo Mex'. The parents, F1 hybrids, and F2 populations were evaluated for BPW damage in 1992. Backcrosses of the F1 of Jamapa/Pinto 168 to the respective susceptible and resistant parents were also evaluated in 1992. All seven resistant accessions were crossed in all possible combinations, excluding reciprocals. The resulting 21 F1 hybrids and 21 F2 populations were evaluated for BPW damage in 1994. 'J 117' had the highest level of resistance to BPW. 'Pinto Texcoco' and 'Puebla 36' had the highest mean damage score of all seven sources of resistance. The F1 hybrids between susceptible parents and resistant sources were generally intermediate. Two genes segregating independently controlled the BPW resistance in each accession. One gene, Agm, has no effect when present alone, whereas the other gene, Agr, alone conferred intermediate resistance. When both genes were present, resistance to BPW was higher. Based on mean BPW damage scores, all 21 F1 hybrids

Effect of ECAP processing on corrosion resistance of AE21 and AE42 magnesium alloys

NASA Astrophysics Data System (ADS)

Minárik, P.; Král, R.; Janeček, M.

2013-09-01

Corrosion properties of AE21 and AE42 magnesium alloys were investigated in the extruded state and after subsequent 8 passes of Equal Channel Angular Pressing (ECAP) via route Bc, by Electrochemical Impedance Spectroscopy (EIS) in 0.1 M NaCl solution. The resulting microstructure was observed by the Transmission Electron Microscope (TEM) and the Scanning Electron Microscope (SEM). Corrosion layer created after 7 days of immersion was observed by (SEM) in order to explain different evolution of the corrosion resistance after ECAP processing in both alloys. It was found that Al-rich Al11RE3 dispersed particles (present in both alloys) strongly influence the corrosion process and enhance the corrosion resistance. Ultra-fine grained structure was found to reduce the corrosion resistance in AE21. On the other hand, the microstructure of AE42 after ECAP and particularly the better distribution of the alloying elements in the matrix enhance the corrosion resistance when compared to the extruded material.

Computer Conferences and Learning: Authority, Resistance, and Internally Persuasive Discourse.

ERIC Educational Resources Information Center

Cooper, Marilyn M.; Selfe, Cynthia L.

1990-01-01

Describes a nontraditional discourse forum, computer-based conferences, in which students hold written conversations to discuss readings, debate issues, share frustrations, and try to become comfortable with the ideas presented in the classroom. Argues that these computer conferences are powerful learning forums for students because they encourage…

QTL mapping of downy and powdery mildew resistances in PI 197088 cucumber with genotyping-by-sequencing in RIL population.

PubMed

Wang, Yuhui; VandenLangenberg, Kyle; Wen, Changlong; Wehner, Todd C; Weng, Yiqun

2018-03-01

Host resistances in PI 197088 cucumber to downy and powdery mildew pathogens are conferred by 11 (3 with major effect) and 4 (1 major effect) QTL, respectively, and three of which are co-localized. The downy mildew (DM) and powdery mildew (PM) are the two most important foliar diseases of cucurbit crops worldwide. The cucumber accession PI 197088 exhibits high-level resistances to both pathogens. Here, we reported QTL mapping results for DM and PM resistances with 148 recombinant inbred lines from a cross between PI 197088 and the susceptible line 'Coolgreen'. Phenotypic data on responses to natural DM and PM infection were collected in multi-year and multi-location replicated field trials. A high-density genetic map with 2780 single nucleotide polymorphisms (SNPs) from genotyping-by-sequencing and 55 microsatellite markers was developed, which revealed genomic regions with segregation distortion and mis-assemblies in the '9930' cucumber draft genome. QTL analysis identified 11 and 4 QTL for DM and PM resistances accounting for more than 73.5 and 63.0% total phenotypic variance, respectively. Among the 11 DM resistance QTL, dm5.1, dm5.2, and dm5.3 were major-effect contributing QTL, whereas dm1.1, dm2.1, and dm6.2 conferred susceptibility. Of the 4 QTL for PM resistance, pm5.1 was the major-effect QTL explaining 32.4% phenotypic variance and the minor-effect QTL pm6.1 contributed to disease susceptibility. Three PM QTL, pm2.1, pm5.1, and pm6.1, were co-localized with DM QTL dm2.1, dm5.2, and dm6.1, respectively, which was consistent with the observed linkage of PM and DM resistances in PI 197088. The genetic architecture of DM resistance in PI 197088 and another resistant line WI7120 (PI 330628) was compared, and the potential of using PI 197088 in cucumber breeding for downy and powdery mildew resistances is discussed.

The identification of candidate rice genes that confer resistance to the brown planthopper (Nilaparvata lugens) through representational difference analysis.

PubMed

Park, Dong-Soo; Lee, Sang-Kyu; Lee, Jong-Hee; Song, Min-Young; Song, Song-Yi; Kwak, Do-Yeon; Yeo, Un-Sang; Jeon, Nam-Soo; Park, Soo-Kwon; Yi, Gihwan; Song, You-Chun; Nam, Min-Hee; Ku, Yeon-Chung; Jeon, Jong-Seong

2007-08-01

The development of rice varieties (Oryza sativa L.) that are resistant to the brown planthopper (BPH; Nilaparvata lugens Stål) is an important objective in current breeding programs. In this study, we generated 132 BC(5)F(5) near-isogenic rice lines (NILs) by five backcrosses of Samgangbyeo, a BPH resistant indica variety carrying the Bph1 locus, with Nagdongbyeo, a BPH susceptible japonica variety. To identify genes that confer BPH resistance, we employed representational difference analysis (RDA) to detect transcripts that were exclusively expressed in one of our BPH resistant NIL, SNBC61, during insect feeding. The chromosomal mapping of the RDA clones that we subsequently isolated revealed that they are located in close proximity either to known quantitative trait loci or to an introgressed SSR marker from the BPH resistant donor parent Samgangbyeo. Genomic DNA gel-blot analysis further revealed that loci of all RDA clones in SNBC61 correspond to the alleles of Samgangbyeo. Most of the RDA clones were found to be exclusively expressed in SNBC61 and could be assigned to functional groups involved in plant defense. These RDA clones therefore represent candidate defense genes for BPH resistance.

Vancouver AIDS conference: special report. A verdict on the conference: sadly, not one world or one hope.

PubMed

Whiteside, A

1996-01-01

Although the theme of the 11th International Conference on AIDS held in Vancouver during July 7-12, 1996, was "One World, One Hope," developed and developing countries have HIV/AIDS epidemics of different magnitudes, different levels of resources with which to combat the problems, and dissimilar objectives. The latest data released at the conference report an estimated 21.8 million people to be currently living with HIV/AIDS, the vast majority of whom live in developing countries. 84% of the estimated 7.7 million AIDS cases which have occurred since the beginning of the pandemic were in Africa or Asia; only 9% were in Europe and the US. The greatest burden of disease is and will be therefore experienced in the developing world which, relative to the developed world, has extremely limited resources. The epidemic continues to spread throughout much of the developing world, while levels of HIV infection in the developed world are largely remaining constant, with the center seemingly moving more into marginalized groups such as the homeless, drug users, and other groups. A whole range of new drugs will soon be available to treat HIV/AIDS among those who can afford them. It is possible that AIDS may simply become manageable as a chronic illness in the west. Such drugs, however, will be prohibitively expensive for almost all people infected with HIV. Moreover, the side effects of these new drugs remain to be seen, and it is possible that individuals will develop resistance to the treatment. The author laments the lack of papers at the conference analyzing the impact of the epidemic and hopes to see more representation and consideration of the developing world at the next conference, to be held in Geneva in 1998.

Identification and functional analysis of a new glyphosate resistance gene from a fungus cDNA library.

PubMed

Tao, Bo; Shao, Bai-Hui; Qiao, Yu-Xin; Wang, Xiao-Qin; Chang, Shu-Jun; Qiu, Li-Juan

2017-08-01

Glyphosate is a widely used broad spectrum herbicide; however, this limits its use once crops are planted. If glyphosate-resistant crops are grown, glyphosate can be used for weed control in crops. While several glyphosate resistance genes are used in commercial glyphosate tolerant crops, there is interest in identifying additional genes for glyphosate tolerance. This research constructed a high-quality cDNA library form the glyphosate-resistant fungus Aspergillus oryzae RIB40 to identify genes that may confer resistance to glyphosate. Using a medium containing glyphosate (120mM), we screened several clones from the library. Based on a nucleotide sequence analysis, we identified a gene of unknown function (GenBank accession number: XM_001826835.2) that encoded a hypothetical 344-amino acid protein. The gene was named MFS40. Its ORF was amplified to construct an expression vector, pGEX-4T-1-MFS40, to express the protein in Escherichia coli BL21. The gene conferred glyphosate tolerance to E. coli ER2799 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

In Vivo-Selected Compensatory Mutations Restore the Fitness Cost of Mosaic penA Alleles That Confer Ceftriaxone Resistance in Neisseria gonorrhoeae.

PubMed

Vincent, Leah R; Kerr, Samuel R; Tan, Yang; Tomberg, Joshua; Raterman, Erica L; Dunning Hotopp, Julie C; Unemo, Magnus; Nicholas, Robert A; Jerse, Ann E

2018-04-03

Resistance to ceftriaxone in Neisseria gonorrhoeae is mainly conferred by mosaic penA alleles that encode penicillin-binding protein 2 (PBP2) variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic penA alleles on gonococcal fitness, we introduced the mosaic penA alleles from two ceftriaxone-resistant (Cro r ) clinical isolates (H041 and F89) into a Cro s strain (FA19) by allelic exchange and showed that the resultant Cro r mutants were significantly outcompeted by the Cro s parent strain in vitro and in a murine infection model. Four Cro r compensatory mutants of FA19 penA41 were isolated independently from mice that outcompeted the parent strain both in vitro and in vivo One of these compensatory mutants (LV41C) displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D) in the acnB gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the acnB G348D allele into FA19 penA41 conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq) analysis of FA19 penA41 acnB G348D revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cro r gonococcal strains that increase metabolism to ameliorate their fitness deficit. IMPORTANCE The emergence of ceftriaxone-resistant (Cro r ) Neisseria gonorrhoeae has led to the looming threat of untreatable gonorrhea. Whether Cro resistance is likely to spread can be predicted from studies that compare the relative fitnesses of

Characterization of a streptomycin-sulfonamide resistance plasmid from Actinobacillus pleuropneumoniae.

PubMed Central

Willson, P J; Deneer, H G; Potter, A; Albritton, W

1989-01-01

An Actinobacillus pleuropneumoniae strain contained a plasmid (pHD8.1) conferring resistance to streptomycin and sulfonamide. Restriction endonuclease mapping and DNA-DNA hybridization showed that pHD8.1 is related to RSF1010 from Salmonella panama, which also confers resistance to streptomycin and sulfonamide, and to pHD148 from Haemophilus ducreyi, which confers resistance only to sulfonamide. Images PMID:2541656

pSTM6-275, a Conjugative IncHI2 Plasmid of Salmonella enterica That Confers Antibiotic and Heavy-Metal Resistance under Changing Physiological Conditions.

PubMed

Billman-Jacobe, Helen; Liu, Yuhong; Haites, Ruth; Weaver, Tom; Robinson, Lily; Marenda, Marc; Dyall-Smith, Mike

2018-05-01

Detailed annotation of an IncHI2 plasmid, pSTM6-275, from Salmonella enterica serotype 1,4,5,12:i:- strain TW-Stm6 revealed a composite structure, including antimicrobial resistance genes on mobile genetic elements. The plasmid was thermosensitive for transfer to Escherichia coli and conferred reduced susceptibility to antibiotics, copper sulfate, and silver nitrate. Metal ion susceptibility was dependent on physiological conditions, giving an insight into the environments where this trait might confer a fitness advantage. Copyright © 2018 Billman-Jacobe et al.

Genetics and mapping of a new anthracnose resistance locus in Andean common bean Paloma.

PubMed

de Lima Castro, Sandra Aparecida; Gonçalves-Vidigal, Maria Celeste; Gilio, Thiago Alexandre Santana; Lacanallo, Giselly Figueiredo; Valentini, Giseli; da Silva Ramos Martins, Vanusa; Song, Qijian; Galván, Marta Zulema; Hurtado-Gonzales, Oscar P; Pastor-Corrales, Marcial Antonio

2017-04-18

The Andean cultivar Paloma is resistant to Mesoamerican and Andean races of Colletotrichum lindemuthianum, the fungal pathogen that causes the destructive anthracnose disease in common bean. Remarkably, Paloma is resistant to Mesoamerican races 2047 and 3481, which are among the most virulent races of the anthracnose pathogen. Most genes conferring anthracnose resistance in common bean are overcome by these races. The genetic mapping and the relationship between the resistant Co-Pa gene of Paloma and previously characterized anthracnose resistance genes can be a great contribution for breeding programs. The inheritance of resistance studies for Paloma was performed in F 2 population from the cross Paloma (resistant) × Cornell 49-242 (susceptible) inoculated with race 2047, and in F 2 and F 2:3 generations from the cross Paloma (resistant) × PI 207262 (susceptible) inoculated with race 3481. The results of these studies demonstrated that a single dominant gene confers the resistance in Paloma. Allelism tests performed with multiple races of C. lindemuthianum showed that the resistance gene in Paloma, provisionally named Co-Pa, is independent from the anthracnose resistance genes Co-1, Co-2, Co-3, Co-4, Co-5, Co-6, Co-12, Co-13, Co-14, Co-15 and Co-16. Bulk segregant analysis using the SNP chip BARCBean6K_3 positioned the approximate location of Co-Pa in the lower arm of chromosome Pv01. Further mapping analysis located the Co-Pa gene at a 390 kb region of Pv01 flanked by SNP markers SS82 and SS83 at a distance of 1.3 and 2.1 cM, respectively. The results presented here showed that Paloma cultivar has a new dominant gene conferring resistance to anthracnose, which is independent from those genes previously described. The linkage between the Co-Pa gene and the SS82 and SS83 SNP markers will be extremely important for marker-assisted introgression of the gene into elite cultivars in order to enhance resistance.

Loss of the RNA polymerase III repressor MAF1 confers obesity resistance.

PubMed

Bonhoure, Nicolas; Byrnes, Ashlee; Moir, Robyn D; Hodroj, Wassim; Preitner, Frédéric; Praz, Viviane; Marcelin, Genevieve; Chua, Streamson C; Martinez-Lopez, Nuria; Singh, Rajat; Moullan, Norman; Auwerx, Johan; Willemin, Gilles; Shah, Hardik; Hartil, Kirsten; Vaitheesvaran, Bhavapriya; Kurland, Irwin; Hernandez, Nouria; Willis, Ian M

2015-05-01

MAF1 is a global repressor of RNA polymerase III transcription that regulates the expression of highly abundant noncoding RNAs in response to nutrient availability and cellular stress. Thus, MAF1 function is thought to be important for metabolic economy. Here we show that a whole-body knockout of Maf1 in mice confers resistance to diet-induced obesity and nonalcoholic fatty liver disease by reducing food intake and increasing metabolic inefficiency. Energy expenditure in Maf1(-/-) mice is increased by several mechanisms. Precursor tRNA synthesis was increased in multiple tissues without significant effects on mature tRNA levels, implying increased turnover in a futile tRNA cycle. Elevated futile cycling of hepatic lipids was also observed. Metabolite profiling of the liver and skeletal muscle revealed elevated levels of many amino acids and spermidine, which links the induction of autophagy in Maf1(-/-) mice with their extended life span. The increase in spermidine was accompanied by reduced levels of nicotinamide N-methyltransferase, which promotes polyamine synthesis, enables nicotinamide salvage to regenerate NAD(+), and is associated with obesity resistance. Consistent with this, NAD(+) levels were increased in muscle. The importance of MAF1 for metabolic economy reveals the potential for MAF1 modulators to protect against obesity and its harmful consequences. © 2015 Bonhoure et al.; Published by Cold Spring Harbor Laboratory Press.

Loss of the RNA polymerase III repressor MAF1 confers obesity resistance

PubMed Central

Bonhoure, Nicolas; Byrnes, Ashlee; Moir, Robyn D.; Hodroj, Wassim; Preitner, Frédéric; Praz, Viviane; Marcelin, Genevieve; Chua, Streamson C.; Martinez-Lopez, Nuria; Singh, Rajat; Moullan, Norman; Auwerx, Johan; Willemin, Gilles; Shah, Hardik; Hartil, Kirsten; Vaitheesvaran, Bhavapriya; Kurland, Irwin

2015-01-01

MAF1 is a global repressor of RNA polymerase III transcription that regulates the expression of highly abundant noncoding RNAs in response to nutrient availability and cellular stress. Thus, MAF1 function is thought to be important for metabolic economy. Here we show that a whole-body knockout of Maf1 in mice confers resistance to diet-induced obesity and nonalcoholic fatty liver disease by reducing food intake and increasing metabolic inefficiency. Energy expenditure in Maf1−/− mice is increased by several mechanisms. Precursor tRNA synthesis was increased in multiple tissues without significant effects on mature tRNA levels, implying increased turnover in a futile tRNA cycle. Elevated futile cycling of hepatic lipids was also observed. Metabolite profiling of the liver and skeletal muscle revealed elevated levels of many amino acids and spermidine, which links the induction of autophagy in Maf1−/− mice with their extended life span. The increase in spermidine was accompanied by reduced levels of nicotinamide N-methyltransferase, which promotes polyamine synthesis, enables nicotinamide salvage to regenerate NAD+, and is associated with obesity resistance. Consistent with this, NAD+ levels were increased in muscle. The importance of MAF1 for metabolic economy reveals the potential for MAF1 modulators to protect against obesity and its harmful consequences. PMID:25934505

DOE Workshop at Tapia Conference

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

Taylor, Valerie

2015-02-19

The DE-SC0013568 DOE Grant, in the amount of $11,822.79, was used to support five doctoral students from underrepresented groups to attend the 2015 Richard Tapia Celebration of Diversity in Computing Conference, held February 18-21 in Boston, MA. Each scholarship was approximately $1200 to cover conference registration, travel, and lodging for the duration of the conference. The remaining $5,822.79 was used to support a DOE Breakfast Workshop during breakfast on Thursday, February 19. The Breakfast supported approximately 140 graduate students from underrepresented groups to learn about the different career opportunities at the different DOE National Laboratories.

Resistance to Bacillus thuringiensis Toxin Cry2Ab in Trichoplusia ni Is Conferred by a Novel Genetic Mechanism

PubMed Central

Song, Xiaozhao; Kain, Wendy; Cassidy, Douglas

2015-01-01

The resistance to the Bacillus thuringiensis (Bt) toxin Cry2Ab in a greenhouse-originated Trichoplusia ni strain resistant to both Bt toxins Cry1Ac and Cry2Ab was characterized. Biological assays determined that the Cry2Ab resistance in the T. ni strain was a monogenic recessive trait independent of Cry1Ac resistance, and there existed no significant cross-resistance between Cry1Ac and Cry2Ab in T. ni. From the dual-toxin-resistant T. ni strain, a strain resistant to Cry2Ab only was isolated, and the Cry2Ab resistance trait was introgressed into a susceptible laboratory strain to facilitate comparative analysis of the Cry2Ab resistance with the susceptible T. ni strain. Results from biochemical analysis showed no significant difference between the Cry2Ab-resistant and -susceptible T. ni larvae in midgut proteases, including caseinolytic proteolytic activity and zymogram profile and serine protease activities, in midgut aminopeptidase and alkaline phosphatase activity, and in midgut esterases and hemolymph plasma melanization activity. For analysis of genetic linkage of Cry2Ab resistance with potential Cry toxin receptor genes, molecular markers for the midgut cadherin, alkaline phosphatase (ALP), and aminopeptidase N (APN) genes were identified between the original greenhouse-derived dual-toxin-resistant and the susceptible laboratory T. ni strains. Genetic linkage analysis showed that the Cry2Ab resistance in T. ni was not genetically associated with the midgut genes coding for the cadherin, ALP, and 6 APNs (APN1 to APN6) nor associated with the ABC transporter gene ABCC2. Therefore, the Cry2Ab resistance in T. ni is conferred by a novel but unknown genetic mechanism. PMID:26025894

Pancreatic adenocarcinoma upregulated factor (PAUF) confers resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNA receptor-mediated signaling

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

Kaowinn, Sirichat; Cho, Il-Rae; Moon, Jeong

2015-04-03

Pancreatic adenocarcinoma upregulated factor (PAUF), a novel oncogene, plays a crucial role in the development of pancreatic cancer, including its metastasis and proliferation. Therefore, PAUF-expressing pancreatic cancer cells could be important targets for oncolytic virus-mediated treatment. Panc-1 cells expressing PAUF (Panc-PAUF) showed relative resistance to parvovirus H-1 infection compared with Panc-1 cells expressing an empty vector (Panc-Vec). Of interest, expression of type I IFN-α receptor (IFNAR) was higher in Panc-PAUF cells than in Panc-Vec cells. Increased expression of IFNAR in turn increased the activation of Stat1 and Tyk2 in Panc-PAUF cells compared with that in Panc-Vec cells. Suppression of Tyk2more » and Stat1, which are important downstream molecules for IFN-α signaling, sensitized pancreatic cancer cells to parvovirus H-1-mediated apoptosis. Further, constitutive suppression of PAUF sensitized Bxpc3 pancreatic cancer cells to parvovirus H-1 infection. Taken together, these results suggested that PAUF conferred resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNAR-mediated signaling. - Highlights: • PAUF confers resistance against oncolytic parvovirus H-1 infection. • PAUF enhances the expression of IFNAR in Panc-1 cells. • Increased activation of Tyk2 or Stat1 by PAUF provides resistance to parvovirus H-1-mediated apoptosis. • Constitutive inhibition of PAUF enhances parvovirus H-1-mediated oncolysis of Bxpc3 pancreatic cancer cells.« less

Connective tissue growth factor confers drug resistance in breast cancer through concomitant up-regulation of Bcl-xL and cIAP1.

PubMed

Wang, Ming-Yang; Chen, Pai-Sheng; Prakash, Ekambaranellore; Hsu, Hsing-Chih; Huang, Hsin-Yi; Lin, Ming-Tsan; Chang, King-Jen; Kuo, Min-Liang

2009-04-15

Connective tissue growth factor (CTGF) expression is elevated in advanced breast cancer and promotes metastasis. Chemotherapy response is only transient in most metastatic diseases. In the present study, we examined whether CTGF expression could confer drug resistance in human breast cancer. In breast cancer patients who received neoadjuvant chemotherapy, CTGF expression was inversely associated with chemotherapy response. Overexpression of CTGF in MCF7 cells (MCF7/CTGF) enhanced clonogenic ability, cell viability, and resistance to apoptosis on exposure to doxorubicin and paclitaxel. Reducing the CTGF level in MDA-MB-231 (MDA231) cells by antisense CTGF cDNA (MDA231/AS cells) mitigated this drug resistance capacity. CTGF overexpression resulted in resistance to doxorubicin- and paclitaxel-induced apoptosis by up-regulation of Bcl-xL and cellular inhibitor of apoptosis protein 1 (cIAP1). Knockdown of Bcl-xL or cIAP1 with specific small interfering RNAs abolished the CTGF-mediated resistance to apoptosis induced by the chemotherapeutic agents in MCF7/CTGF cells. Inhibition of extracellular signal-regulated kinase (ERK)-1/2 effectively reversed the resistance to apoptosis as well as the up-regulation of Bcl-xL and cIAP1 in MCF7/CTGF cells. A neutralizing antibody against integrin alpha(v)beta(3) significantly attenuated CTGF-mediated ERK1/2 activation and up-regulation of Bcl-xL and cIAP1, indicating that the integrin alpha(v)beta(3)/ERK1/2 signaling pathway is essential for CTGF functions. The Bcl-xL level also correlated with the CTGF level in breast cancer patients. We also found that a COOH-terminal domain peptide from CTGF could exert activities similar to full-length CTGF, in activation of ERK1/2, up-regulation of Bcl-xL/cIAP1, and resistance to apoptosis. We conclude that CTGF expression could confer resistance to chemotherapeutic agents through augmenting a survival pathway through ERK1/2-dependent Bcl-xL/cIAP1 up-regulation.

Allotopic expression of a mitochondrial alternative oxidase confers cyanide resistance to human cell respiration

PubMed Central

Hakkaart, Gerrit A J; Dassa, Emmanuel P; Jacobs, Howard T; Rustin, Pierre

2006-01-01

Human mitochondrial respiration is distinct from that of most plants, microorganisms and even some metazoans in that it reduces molecular oxygen only through the highly cyanide-sensitive enzyme cytochrome c oxidase. Here we show that expression of the cyanide-insensitive alternative oxidase (AOX), recently identified in the ascidian Ciona intestinalis, is well tolerated by cultured human cells and confers spectacular cyanide resistance to mitochondrial substrate oxidation. The expressed AOX seems to be confined to mitochondria. AOX involvement in electron flow is triggered by a highly reduced redox status of the respiratory chain (RC) and enhanced by pyruvate; otherwise, the enzyme remains essentially inactive. AOX expression promises to be a valuable tool to limit the deleterious consequences of RC deficiency in human cells and whole animals. PMID:16322757

Emerging Designs for Education: Program, Organization, Operation and Finance. Reports Prepared for an Area Conference (Albuquerque, New Mexico, March 21-22, 1968).

ERIC Educational Resources Information Center

Morphet, Edgar L., Ed.; Jesser, David L., Ed.

The fifth in a series of reports related to long-range educational planning includes five papers presented at a conference in Albuquerque March 21-22, 1968. The first paper outlines the primary goals of an educational program and considers implications of the program for the curriculum, instructional practices, supporting services, evaluation,…

Mutation at codon 442 in the rpoB gene of Mycobacterium leprae does not confer resistance to rifampicin.

PubMed

Lavania, Mallika; Hena, Abu; Reja, Hasanoor; Nigam, Astha; Biswas, Nibir Kumar; Singh, Itu; Turankar, Ravindra P; Gupta, Ud; Kumar, Senthil; Rewaria, Latika; Patra, Pradip K R; Sengupta, Utpal; Bhattacharya, Basudeb

2016-03-01

Rifampicin is the major drug in the treatment of leprosy. The rifampicin resistance of Mycobacterium leprae results from a mutation in the rpoB gene, encoding the β subunit of RNA polymerase. As M. leprae is a non-cultivable organism observation of its growth using mouse food-pad (MFP) is the only Gold Standard assay used for confirmation of "in-vivo" drug resistance. Any mutation at molecular level has to be verified by MFP assay for final confirmation of drug resistance in leprosy. In the present study, M. leprae strains showing a mutation only at codon 442 Gln-His and along with mutation either at codon 424 Val-Gly or at 438 Gln-Val within the Rifampicin Resistance Determining Region (RRDR) confirmed by DNA sequencing and by high resolution melting (HRM) analysis were subjected for its growth in MFP. The M. leprae strain having the new mutation at codon 442 Gln-His was found to be sensitive to all the three drugs and strains having additional mutations at 424 Val-Gly and 438 Gln-Val were conferring resistance with Multi drug therapy (MDT) in MFP. These results indicate that MFP is the gold standard method for confirming the mutations detected by molecular techniques.

Large-scale bioinformatic analysis of the regulation of the disease resistance NBS gene family by microRNAs in Poaceae.

PubMed

Habachi-Houimli, Yosra; Khalfallah, Yosra; Makni, Hanem; Makni, Mohamed; Bouktila, Dhia

2016-01-01

In the present study, we have screened 71, 713, 525, 119 and 241 mature miRNA variants from Hordeum vulgare, Oryza sativa, Brachypodium distachyon, Triticum aestivum, and Sorghum bicolor, respectively, and classified them with respect to their conservation status and expression levels. These Poaceae non-redundant miRNA species (1,669) were distributed over a total of 625 MIR families, among which only 54 were conserved across two or more plant species, confirming the relatively recent evolutionary differentiation of miRNAs in grasses. On the other hand, we have used 257 H. vulgare, 286T. aestivum, 119 B. distachyon, 269 O. sativa, and 139 S. bicolor NBS domains, which were either mined directly from the annotated proteomes, or predicted from whole genome sequence assemblies. The hybridization potential between miRNAs and their putative NBS genes targets was analyzed, revealing that at least 454 NBS genes from all five Poaceae were potentially regulated by 265 distinct miRNA species, most of them expressed in leaves and predominantly co-expressed in additional tissues. Based on gene ontology, we could assign these probable miRNA target genes to 16 functional groups, among which three conferring resistance to bacteria (Rpm1, Xa1 and Rps2), and 13 groups of resistance to fungi (Rpp8,13, Rp3, Tsn1, Lr10, Rps1-k-1, Pm3, Rpg5, and MLA1,6,10,12,13). The results of the present analysis provide a large-scale platform for a better understanding of biological control strategies of disease resistance genes in Poaceae, and will serve as an important starting point for enhancing crop disease resistance improvement by means of transgenic lines with artificial miRNAs. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Accumulation of multiple mutations in linezolid-resistant Staphylococcus epidermidis causing bloodstream infections; in silico analysis of L3 amino acid substitutions that might confer high-level linezolid resistance.

PubMed

Ikonomidis, Alexandros; Grapsa, Anastasia; Pavlioglou, Charikleia; Demiri, Antonia; Batarli, Alexandra; Panopoulou, Maria

2016-12-01

Fifty-six Staphylococcus epidermidis clinical isolates, showing high-level linezolid resistance and causing bacteremia in critically ill patients, were studied. All isolates belonged to ST22 clone and carried the T2504A and C2534T mutations in gene coding for 23SrRNA as well as the C189A, G208A, C209T and G384C missense mutations in L3 protein which resulted in Asp159Tyr, Gly152Asp and Leu94Val substitutions. Other silent mutations were also detected in genes coding for ribosomal proteins L3 and L22. In silico analysis of missense mutations showed that although L3 protein retained the sequence of secondary motifs, the tertiary structure was influenced. The observed alteration in L3 protein folding provides an indication on the putative role of L3-coding gene mutations in high-level linezolid resistance. Furthermore, linezolid pressure in health care settings where linezolid consumption is of high rates might lead to the selection of resistant mutants possessing L3 mutations that might confer high-level linezolid resistance.

Antimicrobial Resistance Expressed by Neisseria gonorrhoeae: A Major Global Public Health Problem in the 21st Century.

PubMed

Unemo, Magnus; Del Rio, Carlos; Shafer, William M

2016-06-01

Neisseria gonorrhoeae is a strictly human pathogen that is typically transmitted by sexual contact. The associated disease gonorrhea has plagued humankind for thousands of years, with a current estimated incidence of 78 million cases per year. Advances in antimicrobial discovery in the 1920s and 1930s leading to the discovery of sulfonamides and penicillin begun the era of effective antimicrobial treatment of gonorrhea. Unfortunately, the gonococcus developed decreased susceptibility or even resistance to these initially employed antibiotics, a trend that continued over subsequent decades with each new antibiotic that was brought into clinical practice. As this pattern of resistance has continued into the 21st century, there is now reason for great concern, especially in an era when few new antibiotics have prospects for use as treatment of gonorrhea. Here, we review the history of gonorrhea treatment regimens and gonococcal resistance to antibiotics, the mechanisms of resistance, resistance monitoring schemes that exist in different international settings, global responses to the challenge of resistance, and prospects for future treatment regimens in the 21st century.

The emergence of factor Xa inhibitors for the treatment of cardiovascular diseases: a patent review.

PubMed

Pinto, Donald J P; Qiao, Jennifer X; Knabb, Robert M

2012-06-01

Factor Xa (FXa) is a critical enzyme in the coagulation cascade responsible for thrombin generation, the final enzyme that leads to fibrin clot formation. Significant success has recently been reported with compounds such as rivaroxaban, apixaban and edoxaban in the treatment and prevention of venous thromboembolism (VTE) and more recently in the prevention of stroke in atrial fibrillation (AF). The success these agents have demonstrated is now being reflected by a narrowing of new FXa patents over the past few years. The new patents appear to be structural modifications of previously published, small molecule inhibitors and bind in a similar manner to the FXa enzyme. SciFinder®, PubMed and Google websites were used as the main source of literature retrieval. Patent searches were conducted in the patent databases: HCAPlus, WPIX and the full text databases (USPAT2, USPATFULL, EPFULL, PCTFULL) using the following keywords: ((FXa) OR (F OR factor) (W) (Xa)) (S) (inhibit? or block? or modulat? or antagonist? or regulat?). The search was restricted to patent documents with the entry date on or after 1 January 2009. Literature and information related to clinical development was retrieved from Thomson Reuter's Pharma. A large body of Phase II and Phase III data is now available for FXa inhibitors such as rivaroxaban, apixaban, edoxaban and betrixaban. The clinical data demonstrate favorable benefit-risk profiles compared with the standards of care for short- and long-term anticoagulation (i.e., low molecular weight heparins (LMWHs) and wafarin). The potential exists that these agents will eventually be the agents of choice for the treatment of a host of cardiovascular disease states, offering improved efficacy, safety, and ease of use compared with existing anticoagulants.

At-line nanofractionation with parallel mass spectrometry and bioactivity assessment for the rapid screening of thrombin and factor Xa inhibitors in snake venoms.

PubMed

Mladic, Marija; Zietek, Barbara M; Iyer, Janaki Krishnamoorthy; Hermarij, Philip; Niessen, Wilfried M A; Somsen, Govert W; Kini, R Manjunatha; Kool, Jeroen

2016-02-01

Snake venoms comprise complex mixtures of peptides and proteins causing modulation of diverse physiological functions upon envenomation of the prey organism. The components of snake venoms are studied as research tools and as potential drug candidates. However, the bioactivity determination with subsequent identification and purification of the bioactive compounds is a demanding and often laborious effort involving different analytical and pharmacological techniques. This study describes the development and optimization of an integrated analytical approach for activity profiling and identification of venom constituents targeting the cardiovascular system, thrombin and factor Xa enzymes in particular. The approach developed encompasses reversed-phase liquid chromatography (RPLC) analysis of a crude snake venom with parallel mass spectrometry (MS) and bioactivity analysis. The analytical and pharmacological part in this approach are linked using at-line nanofractionation. This implies that the bioactivity is assessed after high-resolution nanofractionation (6 s/well) onto high-density 384-well microtiter plates and subsequent freeze drying of the plates. The nanofractionation and bioassay conditions were optimized for maintaining LC resolution and achieving good bioassay sensitivity. The developed integrated analytical approach was successfully applied for the fast screening of snake venoms for compounds affecting thrombin and factor Xa activity. Parallel accurate MS measurements provided correlation of observed bioactivity to peptide/protein masses. This resulted in identification of a few interesting peptides with activity towards the drug target factor Xa from a screening campaign involving venoms of 39 snake species. Besides this, many positive protease activity peaks were observed in most venoms analysed. These protease fingerprint chromatograms were found to be similar for evolutionary closely related species and as such might serve as generic snake protease

A Novel SND1-BRAF Fusion Confers Resistance to c-Met Inhibitor PF-04217903 in GTL16 Cells though MAPK Activation

PubMed Central

Lee, Nathan V.; Lira, Maruja E.; Pavlicek, Adam; Ye, Jingjing; Buckman, Dana; Bagrodia, Shubha; Srinivasa, Sreesha P.; Zhao, Yongjun; Aparicio, Samuel; Rejto, Paul A.; Christensen, James G.; Ching, Keith A.

2012-01-01

Targeting cancers with amplified or abnormally activated c-Met (hepatocyte growth factor receptor) may have therapeutic benefit based on nonclinical and emerging clinical findings. However, the eventual emergence of drug resistant tumors motivates the pre-emptive identification of potential mechanisms of clinical resistance. We rendered a MET amplified gastric cancer cell line, GTL16, resistant to c-Met inhibition with prolonged exposure to a c-Met inhibitor, PF-04217903 (METi). Characterization of surviving cells identified an amplified chromosomal rearrangement between 7q32 and 7q34 which overexpresses a constitutively active SND1-BRAF fusion protein. In the resistant clones, hyperactivation of the downstream MAPK pathway via SND1-BRAF conferred resistance to c-Met receptor tyrosine kinase inhibition. Combination treatment with METi and a RAF inhibitor, PF-04880594 (RAFi) inhibited ERK activation and circumvented resistance to either single agent. Alternatively, treatment with a MEK inhibitor, PD-0325901 (MEKi) alone effectively blocked ERK phosphorylation and inhibited cell growth. Our results suggest that combination of a c-Met tyrosine kinase inhibitor with a BRAF or a MEK inhibitor may be effective in treating resistant tumors that use activated BRAF to escape suppression of c-Met signaling. PMID:22745804

Foreign Language Instructional Technology Conference. Proceedings (3rd, Monterey, California, September 21-24, 1982).

ERIC Educational Resources Information Center

Defense Language Inst., Monterey, CA.

Twenty-five conference papers are presented along with the conference agenda, two welcoming speeches, and lists of conference speakers and participants. The conference focused on the use of video and computer technology in foreign language instruction. The individual papers address such topics as: (1) video design and methodology for foreign…

Pathogens of Bovine Respiratory Disease in North American Feedlots Conferring Multidrug Resistance via Integrative Conjugative Elements

PubMed Central

Klima, Cassidy L.; Zaheer, Rahat; Cook, Shaun R.; Booker, Calvin W.; Hendrick, Steve

2014-01-01

In this study, we determined the prevalence of bovine respiratory disease (BRD)-associated viral and bacterial pathogens in cattle and characterized the genetic profiles, antimicrobial susceptibilities, and nature of antimicrobial resistance determinants in collected bacteria. Nasopharyngeal swab and lung tissue samples from 68 BRD mortalities in Alberta, Canada (n = 42), Texas (n = 6), and Nebraska (n = 20) were screened using PCR for bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus, bovine herpesvirus 1, parainfluenza type 3 virus, Mycoplasma bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Excepting bovine herpesvirus 1, all agents were detected. M. haemolytica (91%) and BVDV (69%) were the most prevalent, with cooccurrence in 63% of the cattle. Isolates of M. haemolytica (n = 55), P. multocida (n = 8), and H. somni (n = 10) from lungs were also collected. Among M. haemolytica isolates, a clonal subpopulation (n = 8) was obtained from a Nebraskan feedlot. All three bacterial pathogens exhibited a high rate of antimicrobial resistance, with 45% exhibiting resistance to three or more antimicrobials. M. haemolytica (n = 18), P. multocida (n = 3), and H. somni (n = 3) from Texas and Nebraska possessed integrative conjugative elements (ICE) that conferred resistance for up to seven different antimicrobial classes. ICE were shown to be transferred via conjugation from P. multocida to Escherichia coli and from M. haemolytica and H. somni to P. multocida. ICE-mediated multidrug-resistant profiles of bacterial BRD pathogens could be a major detriment to many of the therapeutic antimicrobial strategies currently used to control BRD. PMID:24478472

Pathogens of bovine respiratory disease in North American feedlots conferring multidrug resistance via integrative conjugative elements.

PubMed

Klima, Cassidy L; Zaheer, Rahat; Cook, Shaun R; Booker, Calvin W; Hendrick, Steve; Alexander, Trevor W; McAllister, Tim A

2014-02-01

In this study, we determined the prevalence of bovine respiratory disease (BRD)-associated viral and bacterial pathogens in cattle and characterized the genetic profiles, antimicrobial susceptibilities, and nature of antimicrobial resistance determinants in collected bacteria. Nasopharyngeal swab and lung tissue samples from 68 BRD mortalities in Alberta, Canada (n = 42), Texas (n = 6), and Nebraska (n = 20) were screened using PCR for bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus, bovine herpesvirus 1, parainfluenza type 3 virus, Mycoplasma bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Excepting bovine herpesvirus 1, all agents were detected. M. haemolytica (91%) and BVDV (69%) were the most prevalent, with cooccurrence in 63% of the cattle. Isolates of M. haemolytica (n = 55), P. multocida (n = 8), and H. somni (n = 10) from lungs were also collected. Among M. haemolytica isolates, a clonal subpopulation (n = 8) was obtained from a Nebraskan feedlot. All three bacterial pathogens exhibited a high rate of antimicrobial resistance, with 45% exhibiting resistance to three or more antimicrobials. M. haemolytica (n = 18), P. multocida (n = 3), and H. somni (n = 3) from Texas and Nebraska possessed integrative conjugative elements (ICE) that conferred resistance for up to seven different antimicrobial classes. ICE were shown to be transferred via conjugation from P. multocida to Escherichia coli and from M. haemolytica and H. somni to P. multocida. ICE-mediated multidrug-resistant profiles of bacterial BRD pathogens could be a major detriment to many of the therapeutic antimicrobial strategies currently used to control BRD.

Incorporating New Technologies for 21st Century Toxicity ...

EPA Pesticide Factsheets

Presentation at the GlobalChem conference in Washington, DC on Incorporating New Technologies for 21st Century Toxicity Testing and Risk Assessment Presentation at the GlobalChem conference in Washington, DC on Incorporating New Technologies for 21st Century Toxicity Testing and Risk Assessment

Multidrug resistance transporters Snq2p and Pdr5p mediate caffeine efflux in Saccharomyces cerevisiae.

PubMed

Tsujimoto, Yoshiyuki; Shimizu, Yoshihiro; Otake, Kazuya; Nakamura, Tatsuya; Okada, Ryutaro; Miyazaki, Toshitaka; Watanabe, Kunihiko

2015-01-01

SNQ2 was identified as a caffeine-resistance gene by screening a genomic library of Saccharomyces cerevisiae in a multicopy vector YEp24. SNQ2 encodes an ATP-binding cassette transporter and is highly homologous to PDR5. Multicopy of PDR5 also conferred resistance to caffeine, while its resistance was smaller than that of SNQ2. Residual caffeine contents were analyzed after transiently exposing cells to caffeine. The ratios of caffeine contents were 21.3 ± 8.8% (YEp24-SNQ2) and 81.9 ± 8.7% (YEp24-PDR5) relative to control (YEp24, 100%). In addition, multicopies of SNQ2 or PDR5 conferred resistance to rhodamine 6G (R6G), which was widely used as a substrate for transport assay. R6G was exported by both transporters, and their efflux activities were inhibited by caffeine with half-maximal inhibitory concentrations of 5.3 ± 1.9 (YEp24-SNQ2) and 17.2 ± 9.6 mM (YEp24-PDR5). These results demonstrate that Snq2p is a more functional transporter of caffeine than Pdr5p in yeast cells.

Twelve-week combined resistance and aerobic training confers greater benefits than aerobic training alone in nondialysis CKD.

PubMed

Watson, Emma L; Gould, Douglas W; Wilkinson, Thomas J; Xenophontos, Soteris; Clarke, Amy L; Vogt, Barbara Perez; Viana, João L; Smith, Alice C

2018-06-01

There is a growing consensus that patients with chronic kidney disease (CKD) should engage in regular exercise, but there is a lack of formal guidelines. In this report, we determined whether combined aerobic and resistance exercise would elicit superior physiological gains, in particular muscular strength, compared with aerobic training alone in nondialysis CKD. Nondialysis patients with CKD stages 3b-5 were randomly allocated to aerobic exercise {AE, n = 21; 9 men; median age 63 [interquartile range (IQR) 58-71] yr; median estimated glomerular filtration rate (eGFR) 24 (IQR 20-30) ml·min -1 ·1.73 m -2 } or combined exercise [CE, n = 20, 9 men, median age 63 (IQR 51-69) yr, median eGFR 27 (IQR 22-32) ml·min -1 ·1.73 m -2 ], preceded by a 6-wk run-in control period. Patients then underwent 12 wk of supervised AE (treadmill, rowing, or cycling exercise) or CE training (as AE plus leg extension and leg press exercise) performed three times per week. Outcome assessments of knee extensor muscle strength, quadriceps muscle volume, exercise capacity, and central hemodynamics were performed at baseline, following the 6-wk control period, and at the end of the intervention. AE and CE resulted in significant increases in knee extensor strength of 16 ± 19% (mean ± SD; P = 0.001) and 48 ± 37% ( P < 0.001), respectively, which were greater after CE ( P = 0.02). AE and CE resulted in 5 ± 7% ( P = 0.04) and 9 ± 7% ( P < 0.001) increases in quadriceps volume, respectively ( P < 0.001), which were greater after CE ( P = 0.01). Both AE and CE increased distance walked in the incremental shuttle walk test [28 ± 44 m ( P = 0.01) and 32 ± 45 m ( P = 0.01), respectively]. In nondialysis CKD, the addition of resistance exercise to aerobic exercise confers greater increases in muscle mass and strength than aerobic exercise alone.

Distinct Detoxification Mechanisms Confer Resistance to Mesotrione and Atrazine in a Population of Waterhemp1[C][W][OPEN

PubMed Central

Ma, Rong; Kaundun, Shiv S.; Tranel, Patrick J.; Riggins, Chance W.; McGinness, Daniel L.; Hager, Aaron G.; Hawkes, Tim; McIndoe, Eddie; Riechers, Dean E.

2013-01-01

Previous research reported the first case of resistance to mesotrione and other 4-hydroxyphenylpyruvate dioxygenase (HPPD) herbicides in a waterhemp (Amaranthus tuberculatus) population designated MCR (for McLean County mesotrione- and atrazine-resistant). Herein, experiments were conducted to determine if target site or nontarget site mechanisms confer mesotrione resistance in MCR. Additionally, the basis for atrazine resistance was investigated in MCR and an atrazine-resistant but mesotrione-sensitive population (ACR for Adams County mesotrione-sensitive but atrazine-resistant). A standard sensitive population (WCS for Wayne County herbicide-sensitive) was also used for comparison. Mesotrione resistance was not due to an alteration in HPPD sequence, HPPD expression, or reduced herbicide absorption. Metabolism studies using whole plants and excised leaves revealed that the time for 50% of absorbed mesotrione to degrade in MCR was significantly shorter than in ACR and WCS, which correlated with previous phenotypic responses to mesotrione and the quantity of the metabolite 4-hydroxy-mesotrione in excised leaves. The cytochrome P450 monooxygenase inhibitors malathion and tetcyclacis significantly reduced mesotrione metabolism in MCR and corn (Zea mays) excised leaves but not in ACR. Furthermore, malathion increased mesotrione activity in MCR seedlings in greenhouse studies. These results indicate that enhanced oxidative metabolism contributes significantly to mesotrione resistance in MCR. Sequence analysis of atrazine-resistant (MCR and ACR) and atrazine-sensitive (WCS) waterhemp populations detected no differences in the psbA gene. The times for 50% of absorbed atrazine to degrade in corn, MCR, and ACR leaves were shorter than in WCS, and a polar metabolite of atrazine was detected in corn, MCR, and ACR that cochromatographed with a synthetic atrazine-glutathione conjugate. Thus, elevated rates of metabolism via distinct detoxification mechanisms contribute to

Deoxycytidine kinase is downregulated under hypoxic conditions and confers resistance against cytarabine in acute myeloid leukaemia.

PubMed

Degwert, Nicole; Latuske, Emily; Vohwinkel, Gabi; Stamm, Hauke; Klokow, Marianne; Bokemeyer, Carsten; Fiedler, Walter; Wellbrock, Jasmin

2016-09-01

Leukaemia initiating cells reside within specialised niches in the bone marrow where they undergo complex interactions with different stromal cell types. The bone marrow niche is characterised by a low oxygen content resulting in high expression of hypoxia-inducible factor 1 α in leukaemic cells conferring a negative prognosis to patients with acute myeloid leukaemia (AML). In the current study, we investigated the impact of hypoxic vs. normoxic conditions on the sensitivity of AML cell lines and primary AML blasts to cytarabine. AML cells cultured under 6% oxygen were significantly more resistant against cytarabine compared to cells cultured under normoxic conditions in proliferation and colony-formation assays. Interestingly upon cultivation under hypoxia, the expression of the cytarabine-activating enzyme deoxycytidine kinase was downregulated in all analysed AML cell lines and primary AML samples representing a possible mechanism for resistance to chemotherapy. Furthermore, the downregulation of deoxycytidine kinase could be associated with hypoxia-inducible factor 1 α as treatment with its inhibitor BAY87-2243 hampered the downregulation of deoxycytidine kinase expression under hypoxic conditions. In conclusion, our data reveal that hypoxia-induced downregulation of deoxycytidine kinase represents one stroma-cell-independent mechanism of drug resistance to cytarabine in acute myeloid leukaemia. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Proceedings of the Annual International Conference of the Association for the Education of Teachers in Science (Costa Mesa, California, January 18-21, 2001).

ERIC Educational Resources Information Center

Rubba, Peter A., Ed.; Rye, James A., Ed.; DiBiase, Warren J., Ed.; Crawford, Barbara A., Ed.

This document contains the proceedings of the 2001 Annual International Conference of the Association for the Education of Teachers in Science which was held in Costa Mesa, California, January 18-21, 2001. Papers include: (1) "An Elementary Preservice Teacher's Search for Solutions about the Evolution-Divine Creation Question: The Story of Tracy"…

The targeted inhibition of mitochondrial Hsp90 overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis

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

Yan, Chunlan; Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058; Oh, Joon Seok

Previous studies have reported that a Gamitrinib variant containing triphenylphosphonium (G-TPP) binds to mitochondrial Hsp90 and rapidly inhibits its activity, thus inducing the apoptotic pathway in the cells. Accordingly, G-TPP shows a potential as a promising drug for the treatment of cancer. A cell can die from different types of cell death such as apoptosis, necrosis, necroptosis, and autophagic cell death. In this study, we further investigated the mechanisms and modes of cell death in the G-TPP-treated Hep3B and U937 cell lines. We discovered that G-TPP kills the U937 cells through the apoptotic pathway and the overexpression of Bcl-2 significantlymore » inhibits U937 cell death to G-TPP. We further discovered that G-TPP kills the Hep3B cells by activating necroptosis in combination with the partial activation of caspase-dependent apoptosis. Importantly, G-TPP overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. We also observed that G-TPP induces compensatory autophagy in the Hep3B cell line. We further found that whereas there is a Bcl-2-Beclin 1 interaction in response to G-TPP, silencing the beclin 1 gene failed to block LC3-II accumulation in the Hep3B cells, indicating that G-TPP triggers Beclin 1-independent protective autophagy in Hep3B cells. Taken together, these data reveal that G-TPP induces cell death through a combination of death pathways, including necroptosis and apoptosis, and overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. These findings are important for the therapeutic exploitation of necroptosis as an alternative cell death program to bypass the resistance to apoptosis. Highlights: ► G-TPP binds to mitochondrial Hsp90. ► G-TPP induces apoptosis in U937 human leukemia cancer cells. ► G-TPP induces combination of death pathways in Hep3B cell. ► G-TPP overcomes the resistance conferred by Bcl-2 in Hep3B cells via necroptosis. ► G-TPP triggers Beclin 1

Anti-Xa activity in apixaban overdose: a case report.

PubMed

Barton, James; Wong, Anselm; Graudins, Andis

2016-11-01

Apixaban is a novel oral anticoagulation agent that exerts its effect through direct factor Xa inhibition. We present a case of multi-drug overdose including apixaban with associated apixaban concentrations. A 53 year-old man presented to our metropolitan hospital following a deliberate self-poisoning with 200 mg apixaban, 35 mg ramipril, 105 mg bisoprolol, 280 mg atorvastatin, 6 mg colchicine, 37.4 mg magnesium, 4 × 500 mg paracetamol/9.5 mg codeine/5 mg phenylephrine and alcohol. He developed hypotension that was treated with noradrenaline. His initial and peak apixaban concentration was 1022.6 ng/ml and was associated with only minor bleeding from his femoral central line insertion site, which improved with local compression. Vitamin K 10 mg (at 9 h post-ingestion) and Prothrombinex-VF 2000 units (at 13 h post-ingestion) were also administered without any observed effect on coagulation studies. Apixaban elimination appeared to display first-order kinetics with an elimination half-life of 7.4 h. His plasma apixaban concentration was within the therapeutic dose range 10 h post-ingestion and he recovered uneventfully. A case of apixaban overdose with associated apixaban concentrations is presented. There was rapid resolution of anticoagulation with no demonstrable benefit of currently available clotting factor replacement.

Multiyear evaluation of the durability of the resistance conferred by Ma and RMia genes to Meloidogyne incognita in Prunus under controlled conditions.

PubMed

Khallouk, Samira; Voisin, Roger; Portier, Ulysse; Polidori, Joël; Van Ghelder, Cyril; Esmenjaud, Daniel

2013-08-01

Root-knot nematodes (RKNs) (Meloidogyne spp.) are highly polyphagous pests that parasitize Prunus crops in Mediterranean climates. Breeding for RKN-resistant Prunus cultivars, as an alternative to the now-banned use of nematicides, is a real challenge, because the perennial nature of these trees increases the risk of resistance breakdown. The Ma plum resistance (R) gene, with a complete spectrum, and the RMia peach R gene, with a more restricted spectrum, both provide total control of Meloidogyne incognita, the model parthenogenetic species of the genus and the most important RKN in terms of economic losses. We investigated the durability of the resistance to this nematode conferred by these genes, comparing the results obtained with those for the tomato Mi-1 reference gene. In multiyear experiments, we applied a high and continuous nematode inoculum pressure by cultivating nematode-infested susceptible tomato plants with either Prunus accessions carrying Ma or RMia R genes, or with resistant tomato plants carrying the Mi-1 gene. Suitable conditions for Prunus development were achieved by carrying out the studies in a glasshouse, in controlled conditions allowing a short winter leaf fall and dormancy. We first assessed the plum accession 'P.2175', which is heterozygous for the Ma gene, in two successive 2-year evaluations, for resistance to two M. incognita isolates. Whatever the isolate used, no nematodes reproducing on P.2175 were detected, whereas galls and nematodes reproducing on tomato plants carrying Mi-1 were observed. In a second experiment with the most aggressive isolate, interspecific full-sib material (P.2175 × ['Garfi' almond × 'Nemared' peach]), carrying either Ma or RMia (from Nemared) or both (in the heterozygous state) or neither of these genes, was evaluated for 4 years. No virulent nematodes developed on Prunus spp. carrying R genes, whereas galling and virulent individuals were observed on Mi-1-resistant tomato plants. Thus, the resistance to

ICCG-10: Tenth International Conference on Crystal Growth. Oral presentation abstracts

NASA Technical Reports Server (NTRS)

1992-01-01

Oral presentation abstracts from the tenth International Conference on Crystal Growth (ICCG) (Aug. 16-21, 1992) are provided. Topics discussed at the conference include superconductors, semiconductors, nucleation, crystal growth mechanisms, and laser materials. Organizing committees, ICCG advisory board and officers, and sponsors of the conference are also included.

Programs for the Educationally Disadvantaged: A Report of a Conference on Teaching Children and Youth Who Are Educationally Disadvantaged, May 21-23, 1962, Washington, D.C. Bulletin, 1963, No. 17. OE-35044

ERIC Educational Resources Information Center

Office of Education, US Department of Health, Education, and Welfare, 1963

1963-01-01

Under the auspices of the Instructional Programs Branch of the U.S. Office of Education, a 3-day conference was held May 21-23, 1962, on "Teaching Children and Youth Who Are Educationally Disadvantaged." The conference brought together from all over the Nation acknowledged leaders of public school programs expressly designed to realize…

Mutation of Rv2887, a marR-like gene, confers Mycobacterium tuberculosis resistance to an imidazopyridine-based agent.

PubMed

Winglee, Kathryn; Lun, Shichun; Pieroni, Marco; Kozikowski, Alan; Bishai, William

2015-11-01

Drug resistance is a major problem in Mycobacterium tuberculosis control, and it is critical to identify novel drug targets and new antimycobacterial compounds. We have previously identified an imidazo[1,2-a]pyridine-4-carbonitrile-based agent, MP-III-71, with strong activity against M. tuberculosis. In this study, we evaluated mechanisms of resistance to MP-III-71. We derived three independent M. tuberculosis mutants resistant to MP-III-71 and conducted whole-genome sequencing of these mutants. Loss-of-function mutations in Rv2887 were common to all three MP-III-71-resistant mutants, and we confirmed the role of Rv2887 as a gene required for MP-III-71 susceptibility using complementation. The Rv2887 protein was previously unannotated, but domain and homology analyses suggested it to be a transcriptional regulator in the MarR (multiple antibiotic resistance repressor) family, a group of proteins first identified in Escherichia coli to negatively regulate efflux pumps and other mechanisms of multidrug resistance. We found that two efflux pump inhibitors, verapamil and chlorpromazine, potentiate the action of MP-III-71 and that mutation of Rv2887 abrogates their activity. We also used transcriptome sequencing (RNA-seq) to identify genes which are differentially expressed in the presence and absence of a functional Rv2887 protein. We found that genes involved in benzoquinone and menaquinone biosynthesis were repressed by functional Rv2887. Thus, inactivating mutations of Rv2887, encoding a putative MarR-like transcriptional regulator, confer resistance to MP-III-71, an effective antimycobacterial compound that shows no cross-resistance to existing antituberculosis drugs. The mechanism of resistance of M. tuberculosis Rv2887 mutants may involve efflux pump upregulation and also drug methylation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Mutation of Rv2887, a marR-Like Gene, Confers Mycobacterium tuberculosis Resistance to an Imidazopyridine-Based Agent

PubMed Central

Winglee, Kathryn; Lun, Shichun; Pieroni, Marco; Kozikowski, Alan

2015-01-01

Drug resistance is a major problem in Mycobacterium tuberculosis control, and it is critical to identify novel drug targets and new antimycobacterial compounds. We have previously identified an imidazo[1,2-a]pyridine-4-carbonitrile-based agent, MP-III-71, with strong activity against M. tuberculosis. In this study, we evaluated mechanisms of resistance to MP-III-71. We derived three independent M. tuberculosis mutants resistant to MP-III-71 and conducted whole-genome sequencing of these mutants. Loss-of-function mutations in Rv2887 were common to all three MP-III-71-resistant mutants, and we confirmed the role of Rv2887 as a gene required for MP-III-71 susceptibility using complementation. The Rv2887 protein was previously unannotated, but domain and homology analyses suggested it to be a transcriptional regulator in the MarR (multiple antibiotic resistance repressor) family, a group of proteins first identified in Escherichia coli to negatively regulate efflux pumps and other mechanisms of multidrug resistance. We found that two efflux pump inhibitors, verapamil and chlorpromazine, potentiate the action of MP-III-71 and that mutation of Rv2887 abrogates their activity. We also used transcriptome sequencing (RNA-seq) to identify genes which are differentially expressed in the presence and absence of a functional Rv2887 protein. We found that genes involved in benzoquinone and menaquinone biosynthesis were repressed by functional Rv2887. Thus, inactivating mutations of Rv2887, encoding a putative MarR-like transcriptional regulator, confer resistance to MP-III-71, an effective antimycobacterial compound that shows no cross-resistance to existing antituberculosis drugs. The mechanism of resistance of M. tuberculosis Rv2887 mutants may involve efflux pump upregulation and also drug methylation. PMID:26303802

Examining Social Presence in a Professional Online Conference

ERIC Educational Resources Information Center

Castro, Luisa F.

2016-01-01

The purpose of this multiple case study was to examine the role of social presence in a professional online conference. This study explored how presenters and attendees convey social presence and how might it influence their conference experience. The participants were presenters and attendees registered for the 21st Annual Teaching Colleges and…

ICCG-10: Tenth International Conference on Crystal Growth. Poster presentation abstracts

NASA Technical Reports Server (NTRS)

1992-01-01

Poster presentation abstracts from the tenth International Conference on Crystal Growth (ICCG) (Aug. 16-21, 1992) are provided. Topics discussed at the conference include crystal growth mechanisms, superconductors, semiconductors, laser materials, optical materials, and biomaterials. Organizing committees, ICCG advisory board and officers, and sponsors of the conference are also included.

Multiple Literacies in the 21st Century: The Twenty-Eighth Yearbook: A Peer Reviewed Publication of the College Reading Association, 2006. [Papers from the College Reading Association Conference, 2005

ERIC Educational Resources Information Center

Sampson, Mary Beth, Ed.; Szabo, Susan, Ed.; Falk-Ross, Francine, Ed.; Foote, Martha F., Ed.; Linder, Patricia E., Ed.

2006-01-01

The title of the twenty-eighth yearbook mirrors the theme of the 2005 conference--"Learning in the 21st Century with Traditional and Electronic Literacies." The editors chose the title "Multiple Literacies in the 21st Century" in an attempt to reflect the contents of this yearbook which seem to approach literacy from a myriad…

Preclinical and clinical data for factor Xa and “universal” reversal agents☆,☆☆,★

PubMed Central

Milling, Truman J.; Kaatz, Scott

2017-01-01

Oral Factor Xa (FXa) inhibitors, a growing class of direct-acting anticoagulants, are frequently used to prevent stroke and systemic embolism in patients with atrial fibrillation and to prevent and treat venous thromboembolism. These drugs reduce the risk of clotting at the expense of increasing the risk of bleeding, and currently they have no specific reversal agent. However, andexanet alfa, a recombinant modified FXa decoymolecule, is in a late-phase clinical trial in bleeding patients, and ciraparantag, a small molecule that appears to reverse many anticoagulants including the FXa inhibitors, is in development. This review summarizes the published data to date on both drugs, which have the potential to change the management approach to patients with FXa inhibitoreassociated major hemorrhage. PMID:27697443

Genome-Wide Association Mapping Uncovers Fw1, a Dominant Gene Conferring Resistance to Fusarium Wilt in Strawberry.

PubMed

Pincot, Dominique D A; Poorten, Thomas J; Hardigan, Michael A; Harshman, Julia M; Acharya, Charlotte B; Cole, Glenn S; Gordon, Thomas R; Stueven, Michelle; Edger, Patrick P; Knapp, Steven J

2018-05-04

Fusarium wilt, a soil-borne disease caused by the fungal pathogen Fusarium oxysporum f. sp. fragariae , threatens strawberry ( Fragaria × ananassa ) production worldwide. The spread of the pathogen, coupled with disruptive changes in soil fumigation practices, have greatly increased disease pressure and the importance of developing resistant cultivars. While resistant and susceptible cultivars have been reported, a limited number of germplasm accessions have been analyzed, and contradictory conclusions have been reached in earlier studies to elucidate the underlying genetic basis of resistance. Here, we report the discovery of Fw1 , a dominant gene conferring resistance to Fusarium wilt in strawberry. The Fw1 locus was uncovered in a genome-wide association study of 565 historically and commercially important strawberry accessions genotyped with 14,408 SNP markers. Fourteen SNPs in linkage disequilibrium with Fw1 physically mapped to a 2.3 Mb segment on chromosome 2 in a diploid F. vesca reference genome. Fw1 and 11 tightly linked GWAS-significant SNPs mapped to linkage group 2C in octoploid segregating populations. The most significant SNP explained 85% of the phenotypic variability and predicted resistance in 97% of the accessions tested-broad-sense heritability was 0.96. Several disease resistance and defense-related gene homologs, including a small cluster of genes encoding nucleotide-binding leucine-rich-repeat proteins, were identified in the 0.7 Mb genomic segment predicted to harbor Fw1 DNA variants and candidate genes identified in the present study should facilitate the development of high-throughput genotyping assays for accurately predicting Fusarium wilt phenotypes and applying marker-assisted selection. Copyright © 2018 Pincot et al.

Development and validation of a breeder-friendly KASPar marker for wheat leaf rust resistance locus Lr21

USDA-ARS?s Scientific Manuscript database

Development and utilization of genetic markers play a pivotal role in marker assisted breeding of wheat cultivars with pyramids of disease resistance genes. The objective of this study is to develop a closed tube, gel-free assay for high throughput genotyping of leaf rust resistance locus Lr21. Poly...

2017 The 7th International Conference on Computer Engineering and Networks

NASA Astrophysics Data System (ADS)

This conference proceeding is a collection of the papers accepted by the CENet 2017 - the 7th International Conference on Computer Engineering and Networks held on Shanghai from 22-23 July, 2017. This proceeding contains the five parts: Part I focuses on Machine learning (21 papers); Part II Wireless communication (21 papers); Part III Information theory (21 papers), Part IV Cloud science (14 papers) and Part V Data analysis (21 papers). Each part can be used as an excellent reference by industry practitioners, university faculty, and undergraduate as well as graduate students who need to build a knowledge base of the most current advances and state-of-practice in the topics covered by this conference proceedings. This will enable them to produce, maintain, and manage systems with high levels of trustworthiness and complexity Thanks go to the authors for their hard work and dedication as well as the reviewers for ensuring the selection of only the highest quality papers; their efforts made this proceedings possible.

Conference report from International Congress on Infectious Diseases 2014: part 2.

PubMed

McLoughlin, Hilda

2014-01-01

This second and final instalment of the conference report from International Congress on Infectious Diseases 2014 follows on from part one, published in Future Microbiology (volume 9/issue 11). The 16th International Congress on Infectious Diseases was held in Cape Town this year, marking the return of the conference to Africa for the first time in 22 years. While infectious diseases such as malaria, tuberculosis and HIV--all still prevalent in the African healthcare landscape--dominated the program, the conference featured several important sessions on fungal infection and a significant number of posters devoted to this critical medical area. Within the context of the rise of antimicrobial resistance, now identified by WHO as one of the three greatest threats to human health, came the message that resistance is not limited to antimicrobials, but that antifungal resistance is also a significant and emerging threat worldwide.

PREFACE: 21st International Conference on Computing in High Energy and Nuclear Physics (CHEP2015)

NASA Astrophysics Data System (ADS)

Sakamoto, H.; Bonacorsi, D.; Ueda, I.; Lyon, A.

2015-12-01

software; data store and access; middleware, software development and tools, experiment frameworks, tools for distributed computing; computing activities and computing models; facilities, infrastructure, network; clouds and virtualization; performance increase and optimization exploiting hardware features. Throughout the entire process, we were blessed with a forward-looking group of competent colleagues in our International Advisory Committee, whom we warmly thank. All the individuals in the Program Committee team, who put together the technical tracks of the conference and reviewed all papers to prepare the sections of this proceedings journal, have to be credited for their outstanding work. And of course the gratitude goes to all people who submitted a contribution, presented it, and spent time to prepare a careful paper to document the work. These people, in the first place, are the main authors of the big success that CHEP continues to be. After almost 30 years, and 21 CHEP editions, this conference cycle continues to stay strong and to evolve in rapidly changing times towards a challenging future, covering new grounds and intercepting new trends as our field of research evolves. The next stop in this journey will be at the 22nd CHEP Conference on October 12th-14th, in San Francisco, hosted by SLAC and LBNL.

Phloem-specific expression of the lectin gene from Allium sativum confers resistance to the sap-sucker Nilaparvata lugens.

PubMed

Chandrasekhar, Kottakota; Vijayalakshmi, Muvva; Vani, Kalasamudramu; Kaul, Tanushri; Reddy, Malireddy K

2014-05-01

Rice production is severely hampered by insect pests. Garlic lectin gene (ASAL) holds great promise in conferring protection against chewing (lepidopteran) and sap-sucking (homopteran) insect pests. We have developed transgenic rice lines resistant to sap-sucking brown hopper (Nilaparvata lugens) by ectopic expression of ASAL in their phloem tissues. Molecular analyses of T0 lines confirmed stable integration of transgene. T1 lines (NP 1-2, 4-3, 11-6 & 17-7) showed active transcription and translation of ASAL transgene. ELISA revealed ASAL expression was as high as 0.95% of total soluble protein. Insect bioassays on T2 homozygous lines (NP 18 & 32) revealed significant reduction (~74-83%) in survival rate, development and fecundity of brown hoppers in comparison to wild type. Transgenics exhibited enhanced resistance (1-2 score) against brown hoppers, minimal plant damage and no growth penalty or phenotypic abnormalities.

Alanine to valine substitutions in the pore helix IIIP1 and linker-helix IIIL45 confer cockroach sodium channel resistance to DDT and pyrethroids.

PubMed

Chen, Mengli; Du, Yuzhe; Nomura, Yoshiko; Zhu, Guonian; Zhorov, Boris S; Dong, Ke

2017-05-01

Pyrethroid insecticides exert toxic effects by prolonging the opening of voltage-gated sodium channels. More than 20 sodium channel mutations from arthropod pests and disease vectors have been confirmed to confer pyrethroid resistance. These mutations have been valuable in elucidating the molecular interaction between pyrethroids and sodium channels, including identification of two pyrethroid receptor sites. Previously, two alanine to valine substitutions, one in the pore helix IIIP1 and the other in the linker-helix connecting S4 and S5 in domain III (IIIL45), were found in Drosophila melanogaster mutants that are resistant to DDT and deltamethrin (a type II pyrethroid with an α-cyano group at the phenylbenzyl alcohol position, which is lacking in type I pyrethroids), but their role in target-site-mediated insecticide resistance has not been functionally confirmed. In this study, we functionally examined the two mutations in cockroach sodium channels expressed in Xenopus laevis oocytes. Both mutations caused depolarizing shifts in the voltage dependence of activation, conferred DDT resistance and also resistance to two Type I pyrethroids by almost abolishing the tail currents induced by Type I pyrethroids. In contrast, neither mutation reduced the amplitude of tail currents induced by the Type II pyrethroids, deltamethrin or cypermethrin. However, both mutations accelerated the decay of Type II pyrethroid-induced tail currents, which normally decay extremely slowly. These results provided new insight into the molecular basis of different actions of Type I and Type II pyrethroids on sodium channels. Computer modeling predicts that both mutations may allosterically affect pyrethroid binding. Copyright © 2016 Elsevier B.V. All rights reserved.

Tensile properties of HK31XA-H24 magnesium-alloy sheet under rapid-heating conditions and constant elevated temperatures

NASA Technical Reports Server (NTRS)

Gibbs, Thomas W

1956-01-01

Specimens of HK31XA-H24 magnesium-alloy sheet from an experimental batch were heated to failure at nominal temperature rates from 0.2 F to 100 F per second under constant-load conditions. Rapid-heating yield and rupture stresses are presented and compared with the yield and ultimate stresses from elevated-temperature tensile stress-strain tests for 1/2-hour exposure. Linear temperature-rate parameters were used to correlate rapid-heating results by constructing master curves which can be used for predicting yield stresses and temperatures and for estimating rupture stresses and temperatures.

Role of a Novel I1781T Mutation and Other Mechanisms in Conferring Resistance to Acetyl-CoA Carboxylase Inhibiting Herbicides in a Black-Grass Population

PubMed Central

Kaundun, Shiv Shankhar; Hutchings, Sarah-Jane; Dale, Richard P.; McIndoe, Eddie

2013-01-01

Background Knowledge of the mechanisms of herbicide resistance is important for designing long term sustainable weed management strategies. Here, we have used an integrated biology and molecular approach to investigate the mechanisms of resistance to acetyl-CoA carboxylase inhibiting herbicides in a UK black-grass population (BG2). Methodology/Principal Findings Comparison between BG2 phenotypes using single discriminant rates of herbicides and genotypes based on ACCase gene sequencing showed that the I1781L, a novel I1781T, but not the W2027C mutations, were associated with resistance to cycloxydim. All plants were killed with clethodim and a few individuals containing the I1781L mutation were partially resistant to tepraloxydim. Whole plant dose response assays demonstrated that a single copy of the mutant T1781 allele conferred fourfold resistance levels to cycloxydim and clodinafop-propargyl. In contrast, the impact of the I1781T mutation was low (Rf = 1.6) and non-significant on pinoxaden. BG2 was also characterised by high levels of resistance, very likely non-target site based, to the two cereal selective herbicides clodinafop-propargyl and pinoxaden and not to the poorly metabolisable cyclohexanedione herbicides. Analysis of 480 plants from 40 cycloxydim resistant black grass populations from the UK using two very effective and high throughput dCAPS assays established for detecting any amino acid changes at the 1781 ACCase codon and for positively identifying the threonine residue, showed that the occurrence of the T1781 is extremely rare compared to the L1781 allele. Conclusion/Significance This study revealed a novel mutation at ACCase codon position 1781 and adequately assessed target site and non-target site mechanisms in conferring resistance to several ACCase herbicides in a black-grass population. It highlights that over time the level of suspected non-target site resistance to some cereal selective ACCase herbicides have in some instances

Identification of ABC transporter genes conferring combined pleuromutilin-lincosamide-streptogramin A resistance in bovine methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci.

PubMed

Wendlandt, Sarah; Kadlec, Kristina; Feßler, Andrea T; Schwarz, Stefan

2015-06-12

The aim of this study was to investigate the genetic basis of combined pleuromutilin-lincosamide-streptogramin A resistance in 26 unrelated methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) from dairy cows suffering from mastitis. The 26 pleuromutilin-resistant staphylococcal isolates were screened for the presence of the genes vga(A), vga(B), vga(C), vga(E), vga(E) variant, sal(A), vmlR, cfr, lsa(A), lsa(B), lsa(C), and lsa(E) by PCR. None of the 26 isolates carried the genes vga(B), vga(C), vga(E), vga(E) variant, vmlR, cfr, lsa(A), lsa(B), or lsa(C). Two Staphylococcus haemolyticus and single Staphylococcus xylosus, Staphylococcus lentus, and Staphylococcus hominis were vga(A)-positive. Twelve S. aureus, two Staphylococcus warneri, as well as single S. lentus and S. xylosus carried the lsa(E) gene. Moreover, single S. aureus, S. haemolyticus, S. xylosus, and Staphylococcus epidermidis were positive for both genes, vga(A) and lsa(E). The sal(A) gene was found in a single Staphylococcus sciuri. All ABC transporter genes were located in the chromosomal DNA, except for a plasmid-borne vga(A) gene in the S. epidermidis isolate. The genetic environment of the lsa(E)-positive isolates was analyzed using previously described PCR assays. Except for the S. warneri and S. xylosus, all lsa(E)-positive isolates harbored a part of the previously described enterococcal multiresistance gene cluster. This is the first report of the novel lsa(E) gene in the aforementioned bovine CoNS species. This is also the first identification of the sal(A) gene in a S. sciuri from a case of bovine mastitis. Moreover, the sal(A) gene was shown to also confer pleuromutilin resistance. Copyright © 2015 Elsevier B.V. All rights reserved.

Introgression of resistance-conferring ALS mutations in herbicide-resistant weedy rice

USDA-ARS?s Scientific Manuscript database

Weedy red rice (Oryza sativa) competes aggressively with rice, reducing yields and grain quality. Clearfield™ rice, a nontransgenic, herbicide-resistant (HR) rice introduced in 2002 to control weedy rice, has resulted in some ALS-resistant weedy rice apparently due to gene flow. Studies were conduct...

Preparing Youth for the 21st Century: The Transition from Education to the Labour Market. Conference Proceedings (Washington, D.C., February 23-24, 1999).

ERIC Educational Resources Information Center

Organisation for Economic Cooperation and Development, Paris (France).

This document contains 15 papers from a conference on preparing youth for the 21st century that was organized by the U.S. Department of Education and the Organisation for Economic Cooperation and Development (OECD). The following papers are included: "Giving Young People a Good Start: The Experience of OECD Countries" (Norman Bowers,…

Impairment of O-antigen production confers resistance to grazing in a model amoeba-cyanobacterium predator-prey system.

PubMed

Simkovsky, Ryan; Daniels, Emy F; Tang, Karen; Huynh, Stacey C; Golden, Susan S; Brahamsha, Bianca

2012-10-09

The grazing activity of predators on photosynthetic organisms is a major mechanism of mortality and population restructuring in natural environments. Grazing is also one of the primary difficulties in growing cyanobacteria and other microalgae in large, open ponds for the production of biofuels, as contaminants destroy valuable biomass and prevent stable, continuous production of biofuel crops. To address this problem, we have isolated a heterolobosean amoeba, HGG1, that grazes upon unicellular and filamentous freshwater cyanobacterial species. We have established a model predator-prey system using this amoeba and Synechococcus elongatus PCC 7942. Application of amoebae to a library of mutants of S. elongatus led to the identification of a grazer-resistant knockout mutant of the wzm ABC O-antigen transporter gene, SynPCC7942_1126. Mutations in three other genes involved in O-antigen synthesis and transport also prevented the expression of O-antigen and conferred resistance to HGG1. Complementation of these rough mutants returned O-antigen expression and susceptibility to amoebae. Rough mutants are easily identifiable by appearance, are capable of autoflocculation, and do not display growth defects under standard laboratory growth conditions, all of which are desired traits for a biofuel production strain. Thus, preventing the production of O-antigen is a pathway for producing resistance to grazing by certain amoebae.

p21WAF1/CIP1 Upregulation through the Stress Granule-Associated Protein CUGBP1 Confers Resistance to Bortezomib-Mediated Apoptosis

PubMed Central

Gareau, Cristina; Fournier, Marie-Josée; Filion, Christine; Coudert, Laetitia; Martel, David; Labelle, Yves; Mazroui, Rachid

2011-01-01

Background p21WAF1/CIP1 is a well known cyclin-dependent kinase inhibitor induced by various stress stimuli. Depending on the stress applied, p21 upregulation can either promote apoptosis or prevent against apoptotic injury. The stress-mediated induction of p21 involves not only its transcriptional activation but also its posttranscriptional regulation, mainly through stabilization of p21 mRNA levels. We have previously reported that the proteasome inhibitor MG132 induces the stabilization of p21 mRNA, which correlates with the formation of cytoplasmic RNA stress granules. The mechanism underlying p21 mRNA stabilization, however, remains unknown. Methodology/Principal Findings We identified the stress granules component CUGBP1 as a factor required for p21 mRNA stabilization following treatment with bortezomib ( =  PS-341/Velcade). This peptide boronate inhibitor of the 26S proteasome is very efficient for the treatment of myelomas and other hematological tumors. However, solid tumors are sometimes refractory to bortezomib treatment. We found that depleting CUGBP1 in cancer cells prevents bortezomib-mediated p21 upregulation. FISH experiments combined to mRNA stability assays show that this effect is largely due to a mistargeting of p21 mRNA in stress granules leading to its degradation. Altering the expression of p21 itself, either by depleting CUGBP1 or p21, promotes bortezomib-mediated apoptosis. Conclusions/Significance We propose that one key mechanism by which apoptosis is inhibited upon treatment with chemotherapeutic drugs might involve upregulation of the p21 protein through CUGBP1. PMID:21637851

Functional vitamin B-6 status and long-term mortality in renal transplant recipients.

PubMed

Minović, Isidor; van der Veen, Anna; van Faassen, Martijn; Riphagen, Ineke J; van den Berg, Else; van der Ley, Claude; Gomes-Neto, António W; Geleijnse, Johanna M; Eggersdorfer, Manfred; Navis, Gerjan J; Kema, Ido P; Bakker, Stephan Jl

2017-12-01

Background: Low plasma concentrations of pyridoxal 5'-phosphate (PLP) are common in renal transplant recipients (RTRs) and confer increased risk of long-term mortality. To our knowledge, it is not known whether low plasma PLP concentrations have functional (i.e., intracellular) consequences and, if so, whether such consequences are associated with increased risk of mortality. Objectives: We assessed the association of plasma PLP with functional vitamin B-6 status and explored the potential association of functional vitamin B-6 status with long-term mortality in RTRs. Design: In a longitudinal cohort of 678 stable RTRs with a median follow-up of 5.3 y (IQR: 4.8-6.1 y) and 297 healthy controls, PLP, plasma 3-hydroxykynurenine (3-HK), and xanthurenic acid (XA) were analyzed via validated assays. PLP was used as direct biomarker for vitamin B-6 status, and the 3-HK:XA ratio was used as functional biomarker of vitamin B-6 status with a higher ratio reflecting worse functional vitamin B-6 status. Results: Median PLP, 3-HK, and XA concentrations were 41 nmol/L (IQR: 29-60 nmol/L), 40.1 nmol/L (IQR: 33.0-48.0 nmol/L), and 19.1 nmol/L (IQR: 14.5-24.9 nmol/L), respectively, in healthy controls compared with 29 nmol/L (IQR: 17-50 nmol/L), 61.5 nmol/L (IQR: 45.6-86.5 nmol/L), and 25.5 nmol/L (IQR: 17.2-40.0 nmol/L), respectively, in RTRs (all P < 0.001). RTRs had a higher median 3-HK:XA ratio (2.38; IQR: 1.68-3.49) than did healthy controls (2.13; IQR: 1.63-2.71) ( P < 0.05). In RTRs, the 3-HK:XA ratio was inversely associated with plasma PLP (β = -0.21, P < 0.001). Moreover, a higher 3-HK:XA ratio was independently associated with increased risk of all-cause mortality (HR per SD increment: 1.30; 95% CI: 1.13, 1.49), cancer mortality (HR per SD increment: 1.47; 95% CI: 1.12, 1.95), and infectious disease mortality (HR per SD increment: 1.50; 95% CI: 1.21, 1.86) in RTRs. Conclusions: Vitamin B-6-deficient RTRs have a worse functional vitamin B-6 status than do healthy controls

Expression of a radish defensin in transgenic wheat confers increased resistance to Fusarium graminearum and Rhizoctonia cerealis.

PubMed

Li, Zhao; Zhou, Miaoping; Zhang, Zengyan; Ren, Lijuan; Du, Lipu; Zhang, Boqiao; Xu, Huijun; Xin, Zhiyong

2011-03-01

Fusarium head blight (scab), primarily caused by Fusarium graminearum, is a devastating disease of wheat (Triticum aestivum L.) worldwide. Wheat sharp eyespot, mainly caused by Rhizoctonia cerealis, is one of the major diseases of wheat in China. The defensin RsAFP2, a small cyteine-rich antifungal protein from radish (Raphanus sativus), was shown to inhibit growth in vitro of agronomically important fungal pathogens, such as F. graminearum and R. cerealis. The RsAFP2 gene was transformed into Chinese wheat variety Yangmai 12 via biolistic bombardment to assess the effectiveness of the defensin in protecting wheat from the fungal pathogens in multiple locations and years. The genomic PCR and Southern blot analyses indicated that RsAFP2 was integrated into the genomes of the transgenic wheat lines and heritable. RT-PCR and Western blot proved that the RsAFP2 was expressed in these transgenic wheat lines. Disease tests showed that four RsAFP2 transgenic lines (RA1-RA4) displayed enhanced resistance to F. graminearum compared to the untransformed Yangmai 12 and the null-segregated plants. Assays on Q-RT-PCR and disease severity showed that the express level of RsAFP2 was associated with the enhanced resistance degree. Two of these transgenic lines (RA1 and RA2) also exhibited enhanced resistance to R. cerealis. These results indicated that the expression of RsAFP2 conferred increased resistance to F. graminearum and R. cerealis in transgenic wheat.

The dominance of the herbicide resistance cost in several Arabidopsis thaliana mutant lines.

PubMed Central

Roux, Fabrice; Gasquez, Jacques; Reboud, Xavier

2004-01-01

Resistance evolution depends upon the balance between advantage and disadvantage (cost) conferred in treated and untreated areas. By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana. The use of allele-specific PCR to discriminate between heterozygous and homozygous plants was used to provide insights into the dominance of the resistance cost, a parameter rarely described. Morphological characters appear more sensitive than fitness (seed production) because 6 vs. 4 differences between resistant and sensitive homozygous plants were detected, respectively. Dominance levels for the fitness cost ranged from recessivity (csr1-1, ixr1-2, and axr1-3) to dominance (axr2-1) to underdominance (aux1-7). Furthermore, the dominance level of the herbicide resistance trait did not predict the dominance level of the cost of resistance. The relationship of our results to theoretical predictions of dominance and the consequences of fitness cost and its dominance in resistance management are discussed. PMID:15020435

Mycobacterium tuberculosis embB codon 306 mutations confer moderately increased resistance to ethambutol in vitro and in vivo.

PubMed

Plinke, Claudia; Walter, Kerstin; Aly, Sahar; Ehlers, Stefan; Niemann, Stefan

2011-06-01

Ethambutol (EMB) is a major component of the first-line therapy of tuberculosis. Mutations in codon 306 of embB (embB306) were suggested as a major resistance mechanism in clinical isolates. To directly analyze the impact of individual embB306 mutations on EMB resistance, we used allelic exchange experiments to generate embB306 mutants of M. tuberculosis H37Rv. The level of EMB resistance conferred by particular mutations was measured in vitro and in vivo after EMB therapy by daily gavage in a mouse model of aerogenic tuberculosis. The wild-type embB306 ATG codon was replaced by embB306 ATC, ATA, or GTG, respectively. All of the obtained embB306 mutants exhibited a 2- to 4-fold increase in EMB MIC compared to the wild-type H37Rv. In vivo, the one selected embB306 GTG mutant required a higher dose of ethambutol to restrict its growth in the lung compared to wild-type H37Rv. These experiments demonstrate that embB306 point mutations enhance the EMB MIC in vitro to a moderate, but significant extent, and reduce the efficacy of EMB treatment in the animal model. We propose that conventional EMB susceptibility testing, in combination with embB306 genotyping, may guide dose adjustment to avoid clinical treatment failure in these low-level resistant strains.

The Second Conference on Lunar Bases and Space Activities of the 21st Century, volume 1

NASA Technical Reports Server (NTRS)

Mendell, Wendell W. (Editor); Alred, John W. (Editor); Bell, Larry S. (Editor); Cintala, Mark J. (Editor); Crabb, Thomas M. (Editor); Durrett, Robert H. (Editor); Finney, Ben R. (Editor); Franklin, H. Andrew (Editor); French, James R. (Editor); Greenberg, Joel S. (Editor)

1992-01-01

These papers comprise a peer-review selection of presentations by authors from NASA, LPI industry, and academia at the Second Conference (April 1988) on Lunar Bases and Space Activities of the 21st Century, sponsored by the NASA Office of Exploration and the Lunar Planetary Institute. These papers go into more technical depth than did those published from the first NASA-sponsored symposium on the topic, held in 1984. Session topics covered by this volume include (1) design and operation of transportation systems to, in orbit around, and on the Moon, (2) lunar base site selection, (3) design, architecture, construction, and operation of lunar bases and human habitats, and (4) lunar-based scientific research and experimentation in astronomy, exobiology, and lunar geology.

Artemisinin-Resistant Malaria: Research Challenges, Opportunities, and Public Health Implications

PubMed Central

Fairhurst, Rick M.; Nayyar, Gaurvika M. L.; Breman, Joel G.; Hallett, Rachel; Vennerstrom, Jonathan L.; Duong, Socheat; Ringwald, Pascal; Wellems, Thomas E.; Plowe, Christopher V.; Dondorp, Arjen M.

2012-01-01

Artemisinin-based combination therapies are the most effective drugs to treat Plasmodium falciparum malaria. Reduced sensitivity to artemisinin monotherapy, coupled with the emergence of parasite resistance to all partner drugs, threaten to place millions of patients at risk of inadequate treatment of malaria. Recognizing the significance and immediacy of this possibility, the Fogarty International Center and the National Institute of Allergy and Infectious Diseases of the U.S. National Institutes of Health convened a conference in November 2010 to bring together the diverse array of stakeholders responding to the growing threat of artemisinin resistance, including scientists from malarious countries in peril. This conference encouraged and enabled experts to share their recent unpublished data from studies that may improve our understanding of artemisinin resistance. Conference sessions addressed research priorities to forestall artemisinin resistance and fostered collaborations between field- and laboratory-based researchers and international programs, with the aim of translating new scientific evidence into public health solutions. Inspired by this conference, this review summarizes novel findings and perspectives on artemisinin resistance, approaches for translating research data into relevant public health information, and opportunities for interdisciplinary collaboration to combat artemisinin resistance. PMID:22855752

Artemisinin-resistant malaria: research challenges, opportunities, and public health implications.

PubMed

Fairhurst, Rick M; Nayyar, Gaurvika M L; Breman, Joel G; Hallett, Rachel; Vennerstrom, Jonathan L; Duong, Socheat; Ringwald, Pascal; Wellems, Thomas E; Plowe, Christopher V; Dondorp, Arjen M

2012-08-01

Artemisinin-based combination therapies are the most effective drugs to treat Plasmodium falciparum malaria. Reduced sensitivity to artemisinin monotherapy, coupled with the emergence of parasite resistance to all partner drugs, threaten to place millions of patients at risk of inadequate treatment of malaria. Recognizing the significance and immediacy of this possibility, the Fogarty International Center and the National Institute of Allergy and Infectious Diseases of the U.S. National Institutes of Health convened a conference in November 2010 to bring together the diverse array of stakeholders responding to the growing threat of artemisinin resistance, including scientists from malarious countries in peril. This conference encouraged and enabled experts to share their recent unpublished data from studies that may improve our understanding of artemisinin resistance. Conference sessions addressed research priorities to forestall artemisinin resistance and fostered collaborations between field- and laboratory-based researchers and international programs, with the aim of translating new scientific evidence into public health solutions. Inspired by this conference, this review summarizes novel findings and perspectives on artemisinin resistance, approaches for translating research data into relevant public health information, and opportunities for interdisciplinary collaboration to combat artemisinin resistance.

FLT3-ITD induces expression of Pim kinases through STAT5 to confer resistance to the PI3K/Akt pathway inhibitors on leukemic cells by enhancing the mTORC1/Mcl-1 pathway.

PubMed

Okada, Keigo; Nogami, Ayako; Ishida, Shinya; Akiyama, Hiroki; Chen, Cheng; Umezawa, Yoshihiro; Miura, Osamu

2018-02-06

FLT3-ITD is the most frequent tyrosine kinase mutation in acute myeloid leukemia (AML) associated with poor prognosis. We previously reported that activation of STAT5 confers resistance to PI3K/Akt inhibitors on the FLT3-ITD-positive AML cell line MV4-11 and 32D cells driven by FLT3-ITD (32D/ITD) but not by FLT3 mutated in the tyrosine kinase domain (32D/TKD). Here, we report the involvement of Pim kinases expressed through STAT5 activation in acquisition of this resistance. The specific pan-Pim kinase inhibitor AZD1208 as well as PIM447 in combination with the PI3K inhibitor GDC-0941 or the Akt inhibitor MK-2206 cooperatively downregulated the mTORC1/4EBP1 pathway, formation of the eIF4E/eIF4G complex, and Mcl-1 expression leading to activation of Bak and Bax to induce caspase-dependent apoptosis synergistically in these cells. These cooperative effects were enhanced or inhibited by knock down of mTOR or expression of its activated mutant, respectively. Overexpression of Mcl-1 conferred the resistance on 32D/ITD cells to combined inhibition of the PI3K/Akt pathway and Pim kinases, while the Mcl-1-specific BH3 mimetic A-1210477 conquered the resistance of MV4-11 cells to GDC-0941. Furthermore, overexpression of Pim-1 in 32D/TKD enhanced the mTORC1/Mcl-1 pathway and partially protected it from the PI3K/Akt inhibitors or the FLT3 inhibitor gilteritinib to confer the resistance to PI3K/Akt inhibitors. Finally, AZD1208 and GDC-0941 cooperatively inhibited the mTORC1/Mcl-1 pathway and reduced viable cell numbers of primary AML cells from some FLT3-ITD positive cases. Thus, Pim kinases may protect the mTORC1/4EBP1/Mcl-1 pathway to confer the resistance to the PI3K/Akt inhibitors on FLT3-ITD cells and represent promising therapeutic targets.

Selenocysteine Confers Resistance to Inactivation by Oxidation in Thioredoxin Reductase: Comparison of Selenium and Sulfur Enzymes†

PubMed Central

Snider, Gregg W.; Ruggles, Erik; Khan, Nadeem; Hondal, Robert J.

2013-01-01

Mammalian thioredoxin reductase (TR) is a selenocysteine (Sec)-containing homodimeric pyridine nucleotide oxidoreductase which catalyzes the reduction of oxidized thioredoxin. We have previously demonstrated the full-length mitochondrial mammalian TR (mTR3) enzyme to be resistant to inactivation from exposure to 50 mM H2O2. Because a Sec residue oxidizes more rapidly than a cysteine (Cys) residue, it has been previously thought that Sec-containing enzymes are “sensitive to oxidation” compared to Cys-orthologs. Here we show for the first time a direct comparison of the abilities of Sec-containing mTR3 and the Cys-ortholog from D. melanogaster (DmTR) to resist inactivation by oxidation from a variety of oxidants including H2O2, hydroxyl radical, peroxynitrite, hypochlorous acid, hypobromous acid, and hypothiocyanous acid. The results show that the Sec-containing TR is far superior to the Cys-ortholog TR in resisting inactivation by oxidation. To further test our hypothesis that the use of Sec confers strong resistance to inactivation by oxidation, we constructed a chimeric enzyme in which we replaced the active site Cys nucleophile of DmTR with a Sec residue using semisynthesis. The chimeric Sec-containing enzyme has similar ability to resist inactivation by oxidation as the wild type Sec-containing TR from mouse mitochondria. The use of Sec in the chimeric enzyme “rescued” the enzyme from oxidant-induced inactivation for all of the oxidants tested in this study, in direct contrast to previous understanding. We discuss two possibilities for this rescue effect from inactivation under identical conditions of oxidative stress: (i) Sec resists over-oxidation and inactivation, whereas a Cys residue can be permanently over-oxidized to the sulfinic acid form, and (ii) Sec protects the body of the enzyme from harmful oxidation by allowing the enzyme to metabolize (turnover) various oxidants much better than a Cys-containing TR. PMID:23865454

Deletion of p21/Cdkn1a confers protective effect against prostate tumorigenesis in transgenic adenocarcinoma of the mouse prostate model

PubMed Central

Jain, Anil K.; Raina, Komal; Agarwal, Rajesh

2013-01-01

Cyclin-dependent kinase inhibitors (CDKIs) p21Cip1/Waf1 (p21) and p27Kip1 (p27) play a determining role in cell cycle progression by regulating CDK activity; however, p21 role in prostate cancer (PCa) is controversial. Whereas p21 upregulation by anticancer agents causes cell cycle arrest in various PCa cell lines, elevated p21 levels have been associated with higher Gleason score, poor survival and increased PCa recurrence. These conflicting findings suggest that more studies are needed to examine p21 role in PCa. Herein, employing genetic approach, transgenic mice harboring p21/Cdkn1a homozygous deletion (p21−/−) were crossed with the transgenic adenocarcinoma of the mouse prostate (TRAMP) mice to characterize in vivo consequences of p21 deletion on prostate tumorigenesis. Lower urogenital tract weight of p21−/−/TRAMP mice was significantly lower than those of p21+/−/TRAMP and TRAMP mice. Histopathology further supported these observations, showing less aggressiveness in prostates of p21−/−/TRAMP. Furthermore, a significantly higher incidence of low-grade prostatic intraepithelial lesions (PIN) with a concomitant reduction in adenocarcinoma incidence was observed in p21−/−/TRAMP mice compared with TRAMP mice. In addition, whereas TRAMP mice showed the presence of poorly differentiated adenocarcinoma lesions, no such lesions were observed in p21/TRAMP transgenic mice. Specifically, there was a significant reduction in the severity of lesions in both p21−/−/TRAMP and p21+/−/TRAMP mice compared with TRAMP mice. Together, our data showed that p21 deletion reduces prostate tumorigenesis by slowing-down progression of PIN (pre-malignant) to adenocarcinoma (malignant), suggesting that intact p21 expression is associated with PCa aggressiveness, while its decreased levels may in fact confer protection against prostate tumorigenesis. PMID:23624841

2016 TRI National Training Conference: Detailed Agenda

EPA Pesticide Factsheets

Agenda listing events, speakers, topics, biographies, and presentations for the 2016 National Training Conference on the Toxics Release Inventory (TRI) and Environmental Conditions in Communities. October 19-21, 2016

Hairpin RNA Targeting Multiple Viral Genes Confers Strong Resistance to Rice Black-Streaked Dwarf Virus.

PubMed

Wang, Fangquan; Li, Wenqi; Zhu, Jinyan; Fan, Fangjun; Wang, Jun; Zhong, Weigong; Wang, Ming-Bo; Liu, Qing; Zhu, Qian-Hao; Zhou, Tong; Lan, Ying; Zhou, Yijun; Yang, Jie

2016-05-11

Rice black-streaked dwarf virus (RBSDV) belongs to the genus Fijivirus in the family of Reoviridae and causes severe yield loss in rice-producing areas in Asia. RNA silencing, as a natural defence mechanism against plant viruses, has been successfully exploited for engineering virus resistance in plants, including rice. In this study, we generated transgenic rice lines harbouring a hairpin RNA (hpRNA) construct targeting four RBSDV genes, S1, S2, S6 and S10, encoding the RNA-dependent RNA polymerase, the putative core protein, the RNA silencing suppressor and the outer capsid protein, respectively. Both field nursery and artificial inoculation assays of three generations of the transgenic lines showed that they had strong resistance to RBSDV infection. The RBSDV resistance in the segregating transgenic populations correlated perfectly with the presence of the hpRNA transgene. Furthermore, the hpRNA transgene was expressed in the highly resistant transgenic lines, giving rise to abundant levels of 21-24 nt small interfering RNA (siRNA). By small RNA deep sequencing, the RBSDV-resistant transgenic lines detected siRNAs from all four viral gene sequences in the hpRNA transgene, indicating that the whole chimeric fusion sequence can be efficiently processed by Dicer into siRNAs. Taken together, our results suggest that long hpRNA targeting multiple viral genes can be used to generate stable and durable virus resistance in rice, as well as other plant species.

blaNDM-21, a new variant of blaNDM in an Escherichia coli clinical isolate carrying blaCTX-M-55 and rmtB.

PubMed

Liu, Lu; Feng, Yu; McNally, Alan; Zong, Zhiyong

2018-06-14

New Delhi MBL (NDM) is a type of carbapenemase; 20 variants of NDM have been identified to date. We have found a new variant of NDM, NDM-21, and describe it here. A carbapenem-resistant Escherichia coli was subjected to WGS using an Illumina X10 sequencer to identify the antimicrobial resistance genes and its ST. The gene encoding the new variant of NDM was cloned into E. coli DH5α, with blaNDM-5 being cloned as the control. Transformants were tested for susceptibility to carbapenems. Mating was performed to obtain the plasmid carrying the new blaNDM gene and the complete plasmid sequence was obtained using long-read MinION sequencing. The E. coli isolate belonged to ST617 and phylogenetic group A. It had a gene encoding NDM-21, a new NDM variant. NDM-21 differs from NDM-5 by a Gly-to-Ser amino acid substitution at position 69 (G69S). NDM-21 retains the same activity against carbapenems as NDM-5. blaNDM-21 is carried by a 46.1 kb IncX3 plasmid, which is self-transmissible, and is located in a complex genetic context as blaNDM-5. The isolate also carried blaCTX-M-55, which encodes an ESBL conferring resistance to aztreonam (which completed its resistance to all clinically available β-lactams), and rmtB, which mediates high-level resistance to aminoglycosides, on an IncFII plasmid. A new NDM variant has been identified and blaNDM-21 has evolved from blaNDM-5 on an IncX3 plasmid.

Inhibition of coagulation proteases Xa and IIa decreases ischemia-reperfusion injuries in a preclinical renal transplantation model.

PubMed

Tillet, Solenne; Giraud, Sébastien; Kerforne, Thomas; Saint-Yves, Thibaut; Joffrion, Sandrine; Goujon, Jean-Michel; Cau, Jerôme; Mauco, Gérard; Petitou, Maurice; Hauet, Thierry

2016-12-01

Coagulation is an important pathway in the pathophysiology of ischemia-reperfusion injuries. In particular, deceased after circulatory death (DCD) donors undergo a no-flow period, a strong activator of coagulation. Hence, therapies influencing the coagulation cascade must be developed. We evaluated the effect of a new highly specific and effective anti-Xa/IIa molecule, with an integrated innovative antidote site (EP217609), in a porcine preclinical model mimicking injuries observed in DCD donor kidney transplantation. Kidneys were clamped for 60 minutes (warm ischemia), then flushed and preserved for 24 hours at 4°C in University of Wisconsin (UW) solution (supplemented or not). EP217609-supplemented UW solution (UW-EP), compared with unfractionated heparin-supplemented UW solution (UW-UFH) or UW alone (UW). A mechanistic investigation was conducted in vitro: addition of EP217609 to endothelial cells during hypoxia at 4°C in the UW solution inhibited thrombin generation during reoxygenation at 37°C in human plasma and reduced tumor necrosis factor alpha, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 messenger RNA cell expressions. In vivo, function recovery was markedly improved in the UW-EP group. Interestingly, levels of thrombin-antithrombin complexes (reflecting thrombin generation) were reduced 60 minutes after reperfusion in the UW-EP group. In addition, 3 months after transplantation, lower fibrosis, epithelial-mesenchymal transition, inflammation, and leukocyte infiltration were observed. Using this new dual anticoagulant, anti-Xa/IIa activity during kidney flush and preservation is protected by reducing thrombin generation at revascularization, improving early function recovery, and decreasing chronic lesions. Such an easy-to-deploy clinical strategy could improve marginal graft outcome. Copyright © 2016 Elsevier Inc. All rights reserved.

Determination of rivaroxaban in patient's plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS).

PubMed

Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo Dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

2017-01-01

Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p < 0.001). In addition, we validated hemolytic, icteric or lipemic plasma samples for rivaroxaban measurement by HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels.

Gene amplification confers glyphosate resistance in Amaranthus palmeri

PubMed Central

Gaines, Todd A.; Zhang, Wenli; Wang, Dafu; Bukun, Bekir; Chisholm, Stephen T.; Shaner, Dale L.; Nissen, Scott J.; Patzoldt, William L.; Tranel, Patrick J.; Culpepper, A. Stanley; Grey, Timothy L.; Webster, Theodore M.; Vencill, William K.; Sammons, R. Douglas; Jiang, Jiming; Preston, Christopher; Leach, Jan E.; Westra, Philip

2009-01-01

The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Increased use of glyphosate over multiple years imposes selective genetic pressure on weed populations. We investigated recently discovered glyphosate-resistant Amaranthus palmeri populations from Georgia, in comparison with normally sensitive populations. EPSPS enzyme activity from resistant and susceptible plants was equally inhibited by glyphosate, which led us to use quantitative PCR to measure relative copy numbers of the EPSPS gene. Genomes of resistant plants contained from 5-fold to more than 160-fold more copies of the EPSPS gene than did genomes of susceptible plants. Quantitative RT-PCR on cDNA revealed that EPSPS expression was positively correlated with genomic EPSPS relative copy number. Immunoblot analyses showed that increased EPSPS protein level also correlated with EPSPS genomic copy number. EPSPS gene amplification was heritable, correlated with resistance in pseudo-F2 populations, and is proposed to be the molecular basis of glyphosate resistance. FISH revealed that EPSPS genes were present on every chromosome and, therefore, gene amplification was likely not caused by unequal chromosome crossing over. This occurrence of gene amplification as an herbicide resistance mechanism in a naturally occurring weed population is particularly significant because it could threaten the sustainable use of glyphosate-resistant crop technology. PMID:20018685

Loss of Cytoplasmic CDK1 Predicts Poor Survival in Human Lung Cancer and Confers Chemotherapeutic Resistance

PubMed Central

Zhang, Chunyu; Elkahloun, Abdel G.; Robertson, Matthew; Gills, Joell J.; Tsurutani, Junji; Shih, Joanna H.; Fukuoka, Junya; Hollander, M. Christine; Harris, Curtis C.; Travis, William D.; Jen, Jin; Dennis, Phillip A.

2011-01-01

The dismal lethality of lung cancer is due to late stage at diagnosis and inherent therapeutic resistance. The incorporation of targeted therapies has modestly improved clinical outcomes, but the identification of new targets could further improve clinical outcomes by guiding stratification of poor-risk early stage patients and individualizing therapeutic choices. We hypothesized that a sequential, combined microarray approach would be valuable to identify and validate new targets in lung cancer. We profiled gene expression signatures during lung epithelial cell immortalization and transformation, and showed that genes involved in mitosis were progressively enhanced in carcinogenesis. 28 genes were validated by immunoblotting and 4 genes were further evaluated in non-small cell lung cancer tissue microarrays. Although CDK1 was highly expressed in tumor tissues, its loss from the cytoplasm unexpectedly predicted poor survival and conferred resistance to chemotherapy in multiple cell lines, especially microtubule-directed agents. An analysis of expression of CDK1 and CDK1-associated genes in the NCI60 cell line database confirmed the broad association of these genes with chemotherapeutic responsiveness. These results have implications for personalizing lung cancer therapy and highlight the potential of combined approaches for biomarker discovery. PMID:21887332

Are there too few women presenting at emergency medicine conferences?

PubMed

Carley, Simon; Carden, Richard; Riley, Rebecca; May, Natalie; Hruska, Katrin; Beardsell, Iain; Johnston, Michelle; Body, Richard

2016-10-01

There is a perception that women are under-represented as speakers at emergency medicine (EM) conferences. We aimed to evaluate the ratio of male to female speakers and the proportion of presenting time by gender at major international EM conferences. Conference programmes of the major English-speaking EM conferences occurring from 2014 to 2015 were obtained. The number of presentations, the gender of the speaker and the duration of each presentation were recorded. We analysed eight major EM conferences. These included 2382 presentations, of which 29.9% (range 22.5%-40.9%) were given by women. In total, 56 104 min of presentations were analysed, of which 27.6% (range 21%-36.7%) were delivered by women. On average, presentations by women were 95 s shorter than presentations by men (23 vs 21 min 25 s). Male speakers exceed female speakers at major EM conferences. The reasons for this imbalance are likely complex and multifactorial and may reflect the gender imbalance within the specialty. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Stable integration and expression of a cry1Ia gene conferring resistance to fall armyworm and boll weevil in cotton plants.

PubMed

Silva, Carliane Rc; Monnerat, Rose; Lima, Liziane M; Martins, Érica S; Melo Filho, Péricles A; Pinheiro, Morganna Pn; Santos, Roseane C

2016-08-01

Boll weevil is a serious pest of cotton crop. Effective control involves applications of chemical insecticides, increasing the cost of production and environmental pollution. The current genetically modified Bt crops have allowed great benefits to farmers but show activity limited to lepidopteran pests. This work reports on procedures adopted for integration and expression of a cry transgene conferring resistance to boll weevil and fall armyworm by using molecular tools. Four Brazilian cotton cultivars were microinjected with a minimal linear cassette generating 1248 putative lines. Complete gene integration was found in only one line (T0-34) containing one copy of cry1Ia detected by Southern blot. Protein was expressed in high concentration at 45 days after emergence (dae), decreasing by approximately 50% at 90 dae. Toxicity of the cry protein was demonstrated in feeding bioassays revealing 56.7% mortality to boll weevil fed buds and 88.1% mortality to fall armyworm fed leaves. A binding of cry1Ia antibody was found in the midgut of boll weevils fed on T0-34 buds in an immunodetection assay. The gene introduced into plants confers resistance to boll weevil and fall armyworm. Transmission of the transgene occurred normally to T1 progeny. All plants showed phenotypically normal growth, with fertile flowers and abundant seeds. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

The diversity of antimicrobial resistance genes among staphylococci of animal origin.

PubMed

Wendlandt, Sarah; Feßler, Andrea T; Monecke, Stefan; Ehricht, Ralf; Schwarz, Stefan; Kadlec, Kristina

2013-08-01

Staphylococci of animal origin harbor a wide variety of resistance genes. So far, more than 40 different resistance genes have been identified in staphylococci from animals. This includes genes that confer resistance to virtually all classes of antimicrobial agents approved for use in animals, such as penicillins, cephalosporins, tetracyclines, macrolides, lincosamides, phenicols, aminoglycosides, aminocyclitols, pleuromutilins, and diaminopyrimidines. The gene products of some of these resistance genes confer resistance to only specific members of a class of antimicrobial agents, whereas others confer resistance to the entire class or even to members of different classes of antimicrobial agents. The resistance mechanisms specified by the resistance genes fall into three major categories: (i) enzymatic inactivation, (ii) active efflux, or (iii) protection/modification/replacement of the cellular target sites of the antimicrobial agents. Mobile genetic elements, in particular plasmids and transposons, play a major role as carriers of antimicrobial resistance genes in animal staphylococci. They facilitate the exchange of resistance genes with staphylococci of human origin but also with other Gram-positive bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

Research in Science Education, Volume 1990. Selected Refereed Papers from the Annual Conference of the Australasian Science Education Research Association (21st, Perth, Western Australia, July 1990).

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