scholarly journals Recent Discovery of Amaranthus palmeri S. Watson in Italy: Characterization of ALS-Resistant Populations and Sensitivity to Alternative Herbicides

2021 ◽  
Vol 13 (13) ◽  
pp. 7003
Author(s):  
Andrea Milani ◽  
Silvia Panozzo ◽  
Silvia Farinati ◽  
Duilio Iamonico ◽  
Maurizio Sattin ◽  
...  
Keyword(s):  
Resistance Mechanism ◽  
Gene Sequencing ◽  
Resistance Mechanisms ◽  
Amaranthus Palmeri ◽  
Soybean Field ◽  
Crop Losses ◽  
Resistance To Herbicides ◽  
Noxious Weed ◽  
Sites Of Action

Amaranthus palmeri S. Watson (Amaranthaceae Juss.) is a dioecious noxious weed, native to the Americas, which infests summer crops. It causes high crop losses, and rapidly evolves resistance to herbicides. In Europe, A. palmeri was recorded mostly as a casual alien, but in 2018 it was reported infesting a soybean field in Italy, and the next year two more populations were found in the same area. Experiments were conducted on these three populations to evaluate the resistance to ALS-inhibiting herbicides, to determine the main resistance mechanisms involved and assess the efficacy of alternative herbicides with different sites of action than ALS. The three populations were confirmed cross-resistant to ALS-inhibiting herbicides (thifensulfuron-methyl and imazamox). Gene sequencing identified a Trp to Leu substitution at position 574 of ALS gene in resistant plants, proving that the main resistance mechanism for the three populations is target-site related. The presence of other resistance mechanisms cannot be excluded. Metobromuron, metribuzin and glyphosate are still effective on these populations.

Characterization of a waterhemp (Amaranthus tuberculatus) population from Illinois resistant to herbicides from five site-of-action groups

2019 ◽  
Vol 33 (03) ◽  
pp. 400-410 ◽  
Author(s):  
Cody M. Evans ◽  
Seth A. Strom ◽  
Dean E. Riechers ◽  
Adam S. Davis ◽  
Patrick J. Tranel ◽  
...  
Keyword(s):  
Field Experiments ◽  
Acetolactate Synthase ◽  
Resistance Mechanisms ◽  
Synthetic Auxin ◽  
Amaranthus Tuberculatus ◽  
Resistance To Herbicides ◽  
Central Illinois ◽  
Sites Of Action ◽  
Herbicide Use

AbstractExperiments were initiated to characterize a waterhemp population (CHR) discovered in a central Illinois corn field after it was not controlled by the 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor topramezone. Field experiments conducted during 2014–2015 indicated that acetolactate synthase (ALS)-, protoporphyrinogen oxidase (PPO)-, photosystem II (PSII)-, and HPPD-inhibiting herbicides and the synthetic auxin 2,4-D did not control the CHR population. Laboratory experiments confirmed target site–based resistance mechanisms to ALS- and PPO-inhibiting herbicides. Herbicide doses required to reduce dry biomass 50% (GR50) were determined in greenhouse dose–response experiments, and indicated 16-fold resistance to the HPPD inhibitor mesotrione, 9.5-fold resistance to the synthetic auxin 2,4-D, and 252-fold resistance to the PSII inhibitor atrazine. Complementary results from field, laboratory, and greenhouse investigations indicate that the CHR population has evolved resistance to herbicides from five sites of action (SOAs): ALS-, PPO-, PSII-, and HPPD-inhibiting herbicides and 2,4-D. Herbicide use history for the field in which CHR was discovered indicates no previous use of 2,4-D.

scholarly journals Characterization of resistance mechanisms of Enterobacter cloacae Complex co-resistant to carbapenem and colistin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shixing Liu ◽  
Renchi Fang ◽  
Ying Zhang ◽  
Lijiang Chen ◽  
Na Huang ◽  
...  
Keyword(s):  
Lipid A ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Carbapenem Resistance ◽  
Enterobacter Cloacae ◽  
Resistance Mechanisms ◽  
Colistin Resistance ◽  
Carbapenem Resistant ◽  
Horizontal Spread

Abstract Background The emergence of carbapenem-resistant and colistin-resistant ECC pose a huge challenge to infection control. The purpose of this study was to clarify the mechanism of the carbapenems and colistin co-resistance in Enterobacter cloacae Complex (ECC) strains. Results This study showed that the mechanisms of carbapenem resistance in this study are: 1. Generating carbapenemase (7 of 19); 2. The production of AmpC or ESBLs combined with decreased expression of out membrane protein (12 of 19). hsp60 sequence analysis suggested 10 of 19 the strains belong to colistin hetero-resistant clusters and the mechanism of colistin resistance is increasing expression of acrA in the efflux pump AcrAB-TolC alone (18 of 19) or accompanied by a decrease of affinity between colistin and outer membrane caused by the modification of lipid A (14 of 19). Moreover, an ECC strain co-harboring plasmid-mediated mcr-4.3 and blaNDM-1 has been found. Conclusions This study suggested that there is no overlap between the resistance mechanism of co-resistant ECC strains to carbapenem and colistin. However, the emergence of strain co-harboring plasmid-mediated resistance genes indicated that ECC is a potential carrier for the horizontal spread of carbapenems and colistin resistance.

scholarly journals Playing the Whack-A-Mole Game: ERK5 Activation Emerges Among the Resistance Mechanisms to RAF-MEK1/2-ERK1/2- Targeted Therapy

2021 ◽  
Vol 9 ◽  
Author(s):  
Alessandro Tubita ◽  
Ignazia Tusa ◽  
Elisabetta Rovida
Keyword(s):  
Tyrosine Kinases ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Mitogen Activated Protein Kinase ◽  
Cancer Therapies ◽  
New Era ◽  
Mitogen Activated Protein ◽  
The Impact ◽  
The Ideal

Molecularly tailored therapies have opened a new era, chronic myeloid leukemia being the ideal example, in the treatment of cancer. However, available therapeutic options are still unsatisfactory in many types of cancer, and often fail due to the occurrence of resistance mechanisms. With regard to small-molecule compounds targeting the components of the Mitogen-Activated Protein Kinase (MAPK) cascade RAF-MEK1/2-ERK1/2, these drugs may result ineffective as a consequence of the activation of compensatory pro-survival/proliferative signals, including receptor tyrosine kinases, PI3K, as well as other components of the MAPK family such as TPL2/COT. The MAPK ERK5 has been identified as a key signaling molecule in the biology of several types of cancer. In this review, we report pieces of evidence regarding the activation of the MEK5-ERK5 pathway as a resistance mechanism to RAF-MEK1/2-ERK1/2 inhibitors. We also highlight the known and possible mechanisms underlying the cross-talks between the ERK1/2 and the ERK5 pathways, the characterization of which is of great importance to maximize, in the future, the impact of RAF-MEK1/2-ERK1/2 targeting. Finally, we emphasize the need of developing additional therapeutically relevant MEK5-ERK5 inhibitors to be used for combined treatments, thus preventing the onset of resistance to cancer therapies relying on RAF-MEK1/2-ERK1/2 inhibitors.

scholarly journals Biological and Transcriptomic Characterization of Pre-Haustorial Resistance to Sunflower Broomrape (Orobanche cumana W.) in Sunflowers (Helianthus annuus)

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1810
Author(s):  
Dana Sisou ◽  
Yaakov Tadmor ◽  
Dina Plakhine ◽  
Hammam Ziadna ◽  
Sariel Hübner ◽  
...  
Keyword(s):  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Orobanche Cumana ◽  
Pathogenesis Related ◽  
Root Parasite ◽  
Sunflower Broomrape ◽  
Visual Screening ◽  
New Races ◽  
Transcription Factor 4

Infestations with sunflower broomrape (Orobanche cumana Wallr.), an obligatory root parasite, constitute a major limitation to sunflower production in many regions around the world. Breeding for resistance is the most effective approach to reduce sunflower broomrape infestation, yet resistance mechanisms are often broken by new races of the pathogen. Elucidating the mechanisms controlling resistance to broomrape at the molecular level is, thus, a desirable way to obtain long-lasting resistance. In this study, we investigated broomrape resistance in a confectionery sunflower cultivar with a robust and long-lasting resistance to sunflower broomrape. Visual screening and histological examination of sunflower roots revealed that penetration of the broomrape haustorium into the sunflower roots was blocked at the cortex, indicating a pre-haustorial mechanism of resistance. A comparative RNA sequencing between broomrape-resistant and -susceptible accessions allowed the identification of genes that were significantly differentially expressed upon broomrape infestation. Among these genes were β-1,3-endoglucanase, β-glucanase, and ethylene-responsive transcription factor 4 (ERF4). These genes were previously reported to be pathogenesis-related in other plant species. This transcriptomic investigation, together with the histological examinations, led us to conclude that the resistance mechanism involves the identification of the broomrape and the consequent formation of a physical barrier that prevents the establishment of the broomrape into the sunflower roots.

scholarly journals Biological and Transcriptomic Characterization of Pre-haustorial Resistance to Sunflower Broomrape (Orobanche cumana W.)

2021 ◽  
Author(s):  
Dana Sisou ◽  
Yaakov Tadmor ◽  
Dina Plakhine ◽  
Sariel Hübner ◽  
Hanan Eizenberg
Keyword(s):  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Differentially Expressed ◽  
Orobanche Cumana ◽  
Resistant Lines ◽  
Pathogenesis Related ◽  
Root Parasite ◽  
Sunflower Broomrape ◽  
New Races

AbstractInfestations with sunflower broomrape (Orobanche cumana Wallr.), an obligatory root parasite, constitute a major limitation to sunflower production in many regions around the world. Breeding for resistance is the most effective approach to reduce sunflower broomrape infestation, yet resistance mechanisms are often overcome by new races of the pathogen. Elucidating the mechanisms controlling the resistance to broomrape at the molecular level is thus the most desirable pathway to obtaining long-lasting resistance and reducing yield loss in sunflower. In this study, we investigated broomrape resistance in a confectionery sunflower hybrid with a robust and long-lasting resistance to sunflower broomrape. Visual screening and histological examination of sunflower roots revealed that penetration of the intrusive broomrape cells into the host root endodermis is blocked at the host cortex, indicating a pre-haustorial mechanism of resistance. A comparative RNA-Seq experiment conducted between roots obtained from the resistant cultivar, a bulk of five broomrape resistant lines and a bulk of five broomrape susceptible lines allowed the identification of genes that were significantly differentially expressed upon broomrape infestation. Among these differentially expressed genes, β-1,3-endoglucanase, β-glucanase and ethylene-responsive transcription factor4 (ERF4) genes were identified. These genes were previously reported to be pathogenesis-related genes in other plant species. This genetics investigation together with the histological examinations led us to conclude that the resistance mechanism involves the identification of the broomrape and the consequent formation of a physical barrier that prevents the penetration of the broomrape into the sunflower roots.

Characterization of Soft-rot-resistant Amorphophallus konjac and Preliminary Analysis of the Resistance Mechanism

2013 ◽  
Vol 48 (3) ◽  
pp. 295-302
Author(s):  
Lei Zhenzhen ◽  
Ye Jinglong ◽  
Cheng Haili ◽  
Chen Yun ◽  
Wang Huixing ◽  
...  
Keyword(s):  
Preliminary Analysis ◽  
Resistance Mechanism ◽  
Soft Rot ◽  
Amorphophallus Konjac

scholarly journals Current Trends in Non-Invasive Imaging of Interactions in the Liver Tumor Microenvironment Mediated by Tumor Metabolism

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3645
Author(s):  
Isabel Theresa Schobert ◽  
Lynn Jeanette Savic
Keyword(s):  
Tumor Microenvironment ◽  
Liver Cancer ◽  
Cancer Cells ◽  
Imaging Techniques ◽  
Treatment Strategies ◽  
Tumor Metabolism ◽  
Resistance Mechanisms ◽  
Metabolic Reprogramming ◽  
Non Invasive

With the increasing understanding of resistance mechanisms mediated by the metabolic reprogramming in cancer cells, there is a growing clinical interest in imaging technologies that allow for the non-invasive characterization of tumor metabolism and the interactions of cancer cells with the tumor microenvironment (TME) mediated through tumor metabolism. Specifically, tumor glycolysis and subsequent tissue acidosis in the realms of the Warburg effect may promote an immunosuppressive TME, causing a substantial barrier to the clinical efficacy of numerous immuno-oncologic treatments. Thus, imaging the varying individual compositions of the TME may provide a more accurate characterization of the individual tumor. This approach can help to identify the most suitable therapy for each individual patient and design new targeted treatment strategies that disable resistance mechanisms in liver cancer. This review article focuses on non-invasive positron-emission tomography (PET)- and MR-based imaging techniques that aim to visualize the crosstalk between tumor cells and their microenvironment in liver cancer mediated by tumor metabolism.

Characterization of carbapenem resistance mechanisms inKlebsiella pneumoniaeandin vitrosynergy of the colistin–meropenem combination

2014 ◽  
Vol 27 (5) ◽  
pp. 277-282 ◽  
Author(s):  
Lakshmana Gowda Krishnappa ◽  
Mohammed Ali M. Marie ◽  
Yazeed A. Al Sheikh
Keyword(s):  
Carbapenem Resistance ◽  
Resistance Mechanisms

scholarly journals Pharmacological Characterization of 5-Hydroxytryptamine-induced Apnea in the Rat. III. Possible Sites of Action.

1991 ◽  
Vol 55 ◽  
pp. 84
Author(s):  
M. Yoshioka ◽  
Y. Goda ◽  
H. Togashi ◽  
M. Matsumoto ◽  
T. Ikeda ◽  
...  
Keyword(s):  
Pharmacological Characterization ◽  
Sites Of Action

scholarly journals Black Queen Evolution and Trophic Interactions Determine Plasmid Survival after the Disruption of the Conjugation Network

mSystems ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Johannes Cairns ◽  
Katariina Koskinen ◽  
Reetta Penttinen ◽  
Tommi Patinen ◽  
Anna Hartikainen ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Communities ◽  
Resistance Mechanism ◽  
Real Life ◽  
Ecological Factors ◽  
Mobile Genetic Elements ◽  
Resistance Mechanisms ◽  
Antibiotics Resistance ◽  
Bacterial Populations ◽  
Genetic Elements

ABSTRACTMobile genetic elements such as conjugative plasmids are responsible for antibiotic resistance phenotypes in many bacterial pathogens. The ability to conjugate, the presence of antibiotics, and ecological interactions all have a notable role in the persistence of plasmids in bacterial populations. Here, we set out to investigate the contribution of these factors when the conjugation network was disturbed by a plasmid-dependent bacteriophage. Phage alone effectively caused the population to lose plasmids, thus rendering them susceptible to antibiotics. Leakiness of the antibiotic resistance mechanism allowing Black Queen evolution (i.e. a “race to the bottom”) was a more significant factor than the antibiotic concentration (lethal vs sublethal) in determining plasmid prevalence. Interestingly, plasmid loss was also prevented by protozoan predation. These results show that outcomes of attempts to resensitize bacterial communities by disrupting the conjugation network are highly dependent on ecological factors and resistance mechanisms.IMPORTANCEBacterial antibiotic resistance is often a part of mobile genetic elements that move from one bacterium to another. By interfering with the horizontal movement and the maintenance of these elements, it is possible to remove the resistance from the population. Here, we show that a so-called plasmid-dependent bacteriophage causes the initially resistant bacterial population to become susceptible to antibiotics. However, this effect is efficiently countered when the system also contains a predator that feeds on bacteria. Moreover, when the environment contains antibiotics, the survival of resistance is dependent on the resistance mechanism. When bacteria can help their contemporaries to degrade antibiotics, resistance is maintained by only a fraction of the community. On the other hand, when bacteria cannot help others, then all bacteria remain resistant. The concentration of the antibiotic played a less notable role than the antibiotic used. This report shows that the survival of antibiotic resistance in bacterial communities represents a complex process where many factors present in real-life systems define whether or not resistance is actually lost.

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