scholarly journals Galium spurium and G. aparine Resistance to ALS-Inhibiting Herbicides in Northern Greece

2019 ◽  
Vol 37 ◽  
Author(s):  
A.P. PAPAPANAGIOTOU ◽  
C.A. DAMALAS ◽  
I. BOSMALI ◽  
P. MADESIS ◽  
G.C. MENEXES ◽  
...  
Keyword(s):  
Amino Acid ◽  
Management Strategies ◽  
Cross Resistance ◽  
Northern Greece ◽  
Abstract Knowledge ◽  
Dna Sequence Alignment ◽  
Whole Plant ◽  
Susceptible Populations ◽  
Galium Spurium ◽  
Selection Of

ABSTRACT: Knowledge of the level of resistance of weed populations and the herbicides to which they survive is important for recommending suitable advice to farmers and allowing the selection of appropriate management strategies. Whole-plant dose response experiments were carried out to assess the resistance status of eight putative resistant Galium spurium L. populations and one G. aparine L. population, originating from northern Greece. High levels of resistance of both species to the ALS-inhibiting herbicides chlorsulfuron and tribenuron were found, while their susceptible populations were controlled. Three G. spurium (GS) populations showed additional cross-resistance to [florasulam + 2,4-D], whereas the remaining five resistant GS populations were controlled with [tribenuron + mecoprop-p], [florasulam + 2,4-D], and [florasulam + aminopyralid]. Also, [florasulam + fluroxypyr] was very effective against two resistant GS populations tested. DNA sequence alignment of the three GS populations (GS 1, GS 6, and GS 8) with cross-resistance to chlorsulfuron, tribenuron, and florasulam revealed a point mutation at Trp-574 (tryptophan-574), causing amino acid substitution by Leu (leucine). The G. aparine (GA) population showed cross-resistance to chlorsulfuron and tribenuron, but it was controlled with [tribenuron + mecoprop-p], [florasulam + aminopyralid], [florasulam + 2,4-D], and [florasulam + fluroxypyr]. The confirmed cross-resistance of both GS and GA species to chlorsulfuron and tribenuron in northern Greece is the first report of Galium spp. resistance to ALS-inhibiting herbicides in Europe. Finally, all populations (8 GS and 1 GA) that showed resistance to chlorsulfuron and tribenuron were controlled with the mixtures [tribenuron + mecoprop-p] and [florasulam + fluroxypyr].

scholarly journals Selection of Replicon Variants Resistant to ACH-806, a Novel Hepatitis C Virus Inhibitor with No Cross-Resistance to NS3 Protease and NS5B Polymerase Inhibitors

2008 ◽  
Vol 52 (6) ◽  
pp. 2043-2052 ◽  
Author(s):  
Wengang Yang ◽  
Yongsen Zhao ◽  
Joanne Fabrycki ◽  
Xiaohong Hou ◽  
Xingtie Nie ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Protease Inhibitors ◽  
Cross Resistance ◽  
Polymerase Inhibitors ◽  
Ns3 Protease Inhibitors ◽  
Ns3 Protease ◽  
Ns5b Polymerase ◽  
Selection Of

ABSTRACT We have discovered a novel class of compounds active against hepatitis C virus (HCV), using a surrogate cellular system, HCV replicon cells. The leading compound in the series, ACH-806 (GS-9132), is a potent and specific inhibitor of HCV. The selection of resistance replicon variants against ACH-806 was performed to map the mutations conferring resistance to ACH-806 and to determine cross-resistance profiles with other classes of HCV inhibitors. Several clones emerged after the addition of ACH-806 to HCV replicon cells at frequencies and durations similar to that observed with NS3 protease inhibitors and NS5B polymerase inhibitors. Phenotypic analyses of these clones revealed that they are resistant to ACH-806 but remain sensitive to other classes of HCV inhibitors. Moreover, no significant change in the susceptibility to ACH-806 was found when the replicon cellular clones resistant to NS3 protease inhibitors and NS5B polymerase inhibitors were examined. Sequencing of the entire coding region of ACH-806-resistant replicon variants yielded several consensus mutations. Reverse genetics identified two single mutations in NS3, a cysteine-to-serine mutation at amino acid 16 and an alanine-to-valine mutation at amino acid 39, that are responsible for the resistance of the replicon variants to ACH-806. Both mutations are located at the N terminus of NS3 where extensive interactions with the central hydrophobic region of NS4A exist. These data provide evidence that ACH-806 inhibits HCV replication by a novel mechanism.

scholarly journals Non-Target-Site Resistance to Herbicides: Recent Developments

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 417 ◽  
Author(s):  
Jugulam ◽  
Shyam
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Target Site ◽  
Cross Resistance ◽  
Weed Species ◽  
Physiological Processes ◽  
Recent Developments ◽  
Target Site Resistance ◽  
Resistance To Herbicides ◽  
Selection Of

Non-target-site resistance (NTSR) to herbicides in weeds can be conferred as a result of the alteration of one or more physiological processes, including herbicide absorption, translocation, sequestration, and metabolism. The mechanisms of NTSR are generally more complex to decipher than target-site resistance (TSR) and can impart cross-resistance to herbicides with different modes of action. Metabolism-based NTSR has been reported in many agriculturally important weeds, although reduced translocation and sequestration of herbicides has also been found in some weeds. This review focuses on summarizing the recent advances in our understanding of the physiological, biochemical, and molecular basis of NTSR mechanisms found in weed species. Further, the importance of examining the co-existence of TSR and NTSR for the same herbicide in the same weed species and influence of environmental conditions in the altering and selection of NTSR is also discussed. Knowledge of the prevalence of NTSR mechanisms and co-existing TSR and NTSR in weeds is crucial for designing sustainable weed management strategies to discourage the further evolution and selection of herbicide resistance in weeds.

scholarly journals Multiple Genetic Pathways Involving Amino Acid Position 143 of HIV-1 Integrase Are Preferentially Associated with Specific Secondary Amino Acid Substitutions and Confer Resistance to Raltegravir and Cross-Resistance to Elvitegravir

2013 ◽  
Vol 57 (9) ◽  
pp. 4105-4113 ◽  
Author(s):  
Wei Huang ◽  
Arne Frantzell ◽  
Signe Fransen ◽  
Christos J. Petropoulos
Keyword(s):  
Amino Acid ◽  
Amino Acid Position ◽  
Amino Acid Sequences ◽  
Resistance Testing ◽  
Cross Resistance ◽  
Genetic Barrier ◽  
Lower Resistance ◽  
Secondary Amino ◽  
Hiv 1 ◽  
Selection Of

ABSTRACTY143C,R substitutions in HIV-1 integrase define one of three primary raltegravir (RAL) resistance pathways. Here we describe clinical isolates with alternative substitutions at position 143 (Y143A, Y143G, Y143H, and Y143S [Y143A,G,H,S]) that emerge less frequently, and we compare the genotypic and phenotypic profiles of these viruses to Y143C,R viruses to reconcile the preferential selection of Y143C,R variants during RAL treatment. Integrase amino acid sequences and RAL susceptibility were characterized in 117 patient isolates submitted for drug resistance testing and contained Y143 amino acid changes. The influence of specific Y143 substitutions on RAL susceptibility and their preferential association with particular secondary substitutions were further defined by evaluating the composition of patient virus populations along with a large panel of site-directed mutants. Our observations demonstrate that the RAL resistance profiles of Y143A,G,H,S viruses and their association with specific secondary substitutions are similar to the well-established Y143C profile but distinct from the Y143R profile. Y143R viruses differ from Y143A,C,G,H,S viruses in that Y143R confers a greater reduction in RAL susceptibility as a single substitution, consistent with a lower resistance barrier. Among Y143A,C,G,H,S viruses, the higher prevalence of Y143C viruses is the result of a lower genetic barrier than that of the Y143A,G,S viruses and a lower resistance barrier than that of the Y143H viruses. In addition, Y143A,C,G,H,S viruses require multiple secondary substitutions to develop large reductions in RAL susceptibility. Patient-derived viruses containing Y143 substitutions exhibit cross-resistance to elvitegravir.

Cross Resistance to Diquat in Glyphosate/Paraquat-Resistant Conyza bonariensis and Conyza canadensis and Confirmation of 2,4-D Resistance in Conyza bonariensis

2021 ◽  
pp. 1-22
Author(s):  
Marcelo L. Moretti ◽  
Lucas K. Bobadilla ◽  
Bradley D. Hanson
Keyword(s):  
Management Strategies ◽  
Resistance Management ◽  
Cross Resistance ◽  
Similar Response ◽  
Weed Species ◽  
Conyza Bonariensis ◽  
Whole Plant ◽  
Site Of Action ◽  
Target Site Resistance ◽  
Sites Of Action

Abstract Hairy fleabane and horseweed are pervasive weed species in agriculture. Glyphosate-resistant (GR) and glyphosate-paraquat-resistant (GPR) biotypes challenge current management strategies. These GR and GPR biotypes have non-target-site-resistance (NTSR), which can confer resistance to herbicides with different sites of action. This study’s objective was to characterize the response of GR, GPR, and glyphosate-paraquat-susceptible (GPS) biotypes of both Conyza spp. to herbicides with a different site of action. Whole-plant dose-response bioassays indicated a similar response among tested biotypes of both Conyza spp. to rimsulfuron, dicamba, hexazinone, glufosinate, flumioxazin, saflufenacil, or mesotrione. The C. bonariensis GR and GPR biotypes were 2.7- and 2.9-fold resistant to 2,4-D relative to the GPS biotype (GR50 766.7 g ai ha-1), confirming 2,4-D resistance in C. bonariensis for the first time in California. The GR and GPR biotypes were not cross-resistant to dicamba. No differences in response to 2,4-D were observed among C. canadensis biotypes with a GR50 ranging from 150.2 to 277.4 g ai ha-1. The GPR biotypes of both species were cross-resistant to diquat with a 44.0-fold resistance in C. bonariensis (GR50 863.7 g ai ha-1) and 15.6-fold resistance in C. canadensis (GR50 563.1 g ai ha-1). The confirmation of multiple resistances to glyphosate, paraquat, and 2,4-D in C. bonariensis curtails herbicide site of action alternatives and jeopardizes resistance management strategies based on herbicide rotation and tank-mixtures, underscoring the critical need for non-chemical weed control alternatives.

Triazine-Resistant Annual Bluegrass (Poa annua) Populations with Ser264Mutation Are Resistant to Amicarbazone

Weed Science ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 355-359 ◽  
Author(s):  
D. H. Perry ◽  
J. S. McElroy ◽  
F. Dane ◽  
E. van Santen ◽  
R. H. Walker
Keyword(s):  
Amino Acid ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Amino Acid Position ◽  
Cross Resistance ◽  
Triazine Herbicides ◽  
Cool Season ◽  
Annual Bluegrass ◽  
Herbicide Treatments ◽  
Susceptible Populations

Amicarbazone is a photosystem II (PSII)-inhibiting herbicide in the triazolinone family, which is similar in mode of action to the triazines. Annual bluegrass is a cool-season weed and has shown resistance to some PSII-inhibiting herbicides. The objective was to evaluate triazine-resistant and -susceptible annual bluegrass populations for potential cross-resistance to amicarbazone. Two triazine-resistant (MS-01, MS-02) and triazine-susceptible (AL-01, COM-01) annual bluegrass populations were treated with amicarbazone, atrazine, and simazine at 0.26, 1.7, and 1.7 kg ai ha−1, respectively. All herbicide treatments controlled the susceptible populations greater than 94% 2 wk after treatment (WAT). No visual injury of MS-01 and MS-02 was observed at any time following herbicide treatment. Quantum yield (ΦPSII) of annual bluegrass was measured 0 to 72 h after application (HAA) to determine the photochemical effects of amicarbazone compared to other PSII inhibitors. ΦPSIIof triazine-susceptible populations was reduced at all measurement times by all three herbicides. However, amicarbazone decreased ΦPSIIof susceptible populations faster and greater than atrazine and simazine at most measurement times. Amicarbazone did not reduce ΦPSIIof the MS-01 population. Amicarbazone significantly reduced ΦPSIIof the MS-02 population during several measurement timings; however, these reductions were short-lived compared to the susceptible populations and no trend in ΦPSIIreduction was observed. Sequencing of thepsbAgene revealed a Ser to Gly substitution at amino acid position 264 known to confer resistance to triazine herbicides. These data indicate amicarbazone efficiently inhibited PSII of susceptible annual bluegrass populations; however, triazine-resistant annual bluegrass populations with Ser264to Gly mutations are cross-resistant to amicarbazone.

Bioluminescent proteins prediction with voting strategy.

2020 ◽  
Vol 15 ◽  
Author(s):  
Shulin Zhao ◽  
Ying Ju ◽  
Xiucai Ye ◽  
Jun Zhang ◽  
Shuguang Han
Keyword(s):  
Amino Acid ◽  
Model Building ◽  
Prediction Method ◽  
Pair Composition ◽  
Proposed Model ◽  
Counting Rules ◽  
Significant Phenomenon ◽  
Voting Strategy ◽  
Improved Accuracy ◽  
Selection Of

Background: Bioluminescence is a unique and significant phenomenon in nature. Bioluminescence is important for the lifecycle of some organisms and is valuable in biomedical research, including for gene expression analysis and bioluminescence imaging technology.In recent years, researchers have identified a number of methods for predicting bioluminescent proteins (BLPs), which have increased in accuracy, but could be further improved. Method: In this paper, we propose a new bioluminescent proteins prediction method based on a voting algorithm. We used four methods of feature extraction based on the amino acid sequence. We extracted 314 dimensional features in total from amino acid composition, physicochemical properties and k-spacer amino acid pair composition. In order to obtain the highest MCC value to establish the optimal prediction model, then used a voting algorithm to build the model.To create the best performing model, we discuss the selection of base classifiers and vote counting rules. Results: Our proposed model achieved 93.4% accuracy, 93.4% sensitivity and 91.7% specificity in the test set, which was better than any other method. We also improved a previous prediction of bioluminescent proteins in three lineages using our model building method, resulting in greatly improved accuracy.

scholarly journals Potential impact of biocide adaptation on selection of antibiotic resistance in bacterial isolates

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Engy Elekhnawy ◽  
Fatma Sonbol ◽  
Ahmed Abdelaziz ◽  
Tarek Elbanna
Keyword(s):  
Antibiotic Resistance ◽  
Cross Resistance ◽  
Main Body ◽  
Bacterial Isolates ◽  
New Agents ◽  
Biocidal Products ◽  
Potential Impact ◽  
Emergence Of Resistance ◽  
Vital Factor ◽  
Selection Of

Abstract Background Antibiotic resistance in pathogenic bacterial isolates has increased worldwide leading to treatment failures. Main body Many concerns are being raised about the usage of biocidal products (including disinfectants, antiseptics, and preservatives) as a vital factor that contributes to the risk of development of antimicrobial resistance which has many environmental and economic impacts. Conclusion Consequently, it is important to recognize the different types of currently used biocides, their mechanisms of action, and their potential impact to develop cross-resistance and co-resistance to various antibiotics. The use of biocides in medical or industrial purposes should be monitored and regulated. In addition, new agents with biocidal activity should be investigated from new sources like phytochemicals in order to decrease the emergence of resistance among bacterial isolates.

scholarly journals Prototypical Recombinant Multi-Protease-Inhibitor-Resistant Infectious Molecular Clones of Human Immunodeficiency Virus Type 1

2013 ◽  
Vol 57 (9) ◽  
pp. 4290-4299 ◽  
Author(s):  
Vici Varghese ◽  
Yumi Mitsuya ◽  
W. Jeffrey Fessel ◽  
Tommy F. Liu ◽  
George L. Melikian ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protease Inhibitor ◽  
Cross Resistance ◽  
Amino Acid Substitutions ◽  
Phenotypic Properties ◽  
The Public ◽  
Immunodeficiency Virus ◽  
The Many ◽  
High Level ◽  
Infectious Molecular Clones

ABSTRACTThe many genetic manifestations of HIV-1 protease inhibitor (PI) resistance present challenges to research into the mechanisms of PI resistance and the assessment of new PIs. To address these challenges, we created a panel of recombinant multi-PI-resistant infectious molecular clones designed to represent the spectrum of clinically relevant multi-PI-resistant viruses. To assess the representativeness of this panel, we examined the sequences of the panel's viruses in the context of a correlation network of PI resistance amino acid substitutions in sequences from more than 10,000 patients. The panel of recombinant infectious molecular clones comprised 29 of 41 study-defined PI resistance amino acid substitutions and 23 of the 27 tightest amino acid substitution clusters. Based on their phenotypic properties, the clones were classified into four groups with increasing cross-resistance to the PIs most commonly used for salvage therapy: lopinavir (LPV), tipranavir (TPV), and darunavir (DRV). The panel of recombinant infectious molecular clones has been made available without restriction through the NIH AIDS Research and Reference Reagent Program. The public availability of the panel makes it possible to compare the inhibitory activities of different PIs with one another. The diversity of the panel and the high-level PI resistance of its clones suggest that investigational PIs active against the clones in this panel will retain antiviral activity against most if not all clinically relevant PI-resistant viruses.

The Evidence for Reduced Glyphosate Efficacy on Acetolactate Synthase–Inhibiting Herbicide-Resistant Yellow Nutsedge (Cyperus esculentus)

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 389-398
Author(s):  
Parsa Tehranchian ◽  
Jason K. Norsworthy ◽  
Matheus Palhano ◽  
Nicholas E. Korres ◽  
Scott McElroy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Production Systems ◽  
Acetolactate Synthase ◽  
Dry Weight ◽  
Cross Resistance ◽  
Purple Nutsedge ◽  
Yellow Nutsedge ◽  
Epsps Gene ◽  
Treated Leaf ◽  
Als Inhibitors

A yellow nutsedge biotype (Res) from an Arkansas rice field has evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. TheResbiotype previously exhibited cross-resistance to ALS inhibitors from four chemical families (imidazolinone, pyrimidinyl benzoate, sulfonylurea, and triazolopyrimidine). Experiments were conducted to evaluate alternative herbicides (i.e., glyphosate, bentazon, propanil, quinclorac, and 2,4-D) currently labeled in Arkansas rice–soybean production systems. Based on the percentage of aboveground dry weight reduction, control of the yellow nutsedge biotypes with the labeled rate of bentazon, propanil, quinclorac, and 2,4-D was < 44%. Glyphosate (867 g ae ha−1) resulted in 68 and > 94% control of theResand susceptible yellow nutsedge biotypes, respectively, at 28 d after treatment. Dose-response studies were conducted to estimate the efficacy of glyphosate on theResbiotype, three susceptible yellow nutsedge biotypes, and purple nutsedge. Based on the dry weights, theResbiotype was ≥ 5- and ≥ 1.3-fold less responsive to glyphosate compared to the susceptible biotypes and purple nutsedge, respectively. Differences in absorption and translocation of radiolabeled glyphosate were observed among the yellow nutsedge biotypes and purple nutsedge. The susceptible biotype had less14C-glyphosate radioactivity in the tissues above the treated leaf and greater radioactivity in tissues below the treated leaf compared to theResbiotype and purple nutsedge. Reduced translocation of glyphosate in tissues below the treated leaf of theResbiotype could be a reason for the lower glyphosate efficacy in theResbiotype. No amino acid substitution that would correspond to glyphosate resistance was found in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene of theResbiotype. However, an amino acid (serine) addition was detected in the EPSPS gene of theResbiotype; albeit, it is not believed that this addition contributes to lower efficacy of glyphosate in this biotype.

scholarly journals Characterization of Resistance to the Nonnucleoside NS5B Inhibitor Filibuvir in Hepatitis C Virus-Infected Patients

2011 ◽  
Vol 56 (3) ◽  
pp. 1331-1341 ◽  
Author(s):  
Philip J. F. Troke ◽  
Marilyn Lewis ◽  
Paul Simpson ◽  
Katrina Gore ◽  
Jennifer Hammond ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Site Directed Mutagenesis ◽  
Phenotypic Resistance ◽  
Number Of Patients ◽  
Chronic Hcv ◽  
Selection Of

ABSTRACTFilibuvir (PF-00868554) is an investigational nonnucleoside inhibitor of the hepatitis C virus (HCV) nonstructural 5B (NS5B) RNA-dependent RNA polymerase currently in development for treating chronic HCV infection. The aim of this study was to characterize the selection of filibuvir-resistant variants in HCV-infected individuals receiving filibuvir as short (3- to 10-day) monotherapy. We identified amino acid M423 as the primary site of mutation arising upon filibuvir dosing. Through bulk cloning of clinical NS5B sequences into a transient-replicon system, and supported by site-directed mutagenesis of the Con1 replicon, we confirmed that mutations M423I/T/V mediate phenotypic resistance. Selection in patients of an NS5B mutation at M423 was associated with a reduced replicative capacityin vitrorelative to the pretherapy sequence; consistent with this, reversion to wild-type M423 was observed in the majority of patients following therapy cessation. Mutations at NS5B residues R422 and M426 were detected in a small number of patients at baseline or the end of therapy and also mediate reductions in filibuvir susceptibility, suggesting these are rare but clinically relevant alternative resistance pathways. Amino acid variants at position M423 in HCV NS5B polymerase are the preferred pathway for selection of viral resistance to filibuvirin vivo.

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