Multiple Resistance to Glyphosate and 2,4-D in Carduus acanthoides L. from Argentina and Alternative Control Solutions

Carduus acanthoides L. is an invasive species native to Europe and distributed in other parts of the world, including North and South America. In Cordoba, Argentina, control failures of this species have been reported in Roundup Ready (RR) soybean crops where glyphosate and 2,4-D have frequently been applied, although there are no confirmed reports worldwide of resistance to glyphosate and 2,4-D in this species. Dose–response tests showed multiple-resistance to both active principles. The resistant population (R) had LD50 values of 1854.27 and 1577.18 g ae ha−1 (grams of acid equivalent per hectare), while the susceptible (S) population had LD50 values of 195.56 and 111.78 g ae ha−1 for glyphosate and 2,4-D, respectively. Low accumulations of shikimic acid (glyphosate) and ethylene (2,4-D) at different doses in the R population compared to the S population support the results observed in the dose–response curves. No significant differences in leaf retention were observed for glyphosate and 2,4-D in the R and S populations. However, the use of adjuvants increased the retention capacity of herbicides in both populations. Ten alternative herbicides with seven different action mechanisms (MOAs) were evaluated and the most effective active principles were dicamba, bromoxynil, atrazine, tembotrione, flazasulfuron, glufosinate, and paraquat. These findings are the first evidence of glyphosate and 2,4 D resistance in C. acanthoides.

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Methacholine dose-response curves in normal and asthmatic man: Effect of starting conductance and pharmacological antagonism

Clinical Science ◽

10.1042/cs0660665 ◽

1984 ◽

Vol 66 (6) ◽

pp. 665-673 ◽

Cited By ~ 11

Author(s):

K. F. Chung ◽

P. D. Snashall

Keyword(s):

Dose Response ◽

Normal Subjects ◽

Small Degree ◽

Response Curves ◽

Significant Difference ◽

Positive Linear Correlation ◽

Dose Response Curves ◽

Dose Dependent Increase ◽

Dose Dependent ◽

Different Doses

1. The bronchial response of 11 normal and ten stable asthmatic subjects to increasing concentrations of methacholine aerosol was assessed by serial measurements of specific airways conductance (scaw) in a body plethysmograph. 2. Cumulative log dose-response curves were constructed. The threshold provocative dose of methacholine needed to cause a 35% fall in starting sCaw (pD35) and the steepest slope of the response were measured from each curve. 3. On separate days subjects were premedicated with 0.9% NaCl solution (control) in duplicate, chlorpheniramine, salbutamol and atropine, the last-named at two different doses, one twice the other. 4. Asthmatic subjects had a lower mean PD35 and a lower mean slope than normal subjects. 5. Pretreatment with salbutamol resulted in a greater increase in sGaw than after atropine but caused a smaller increase in PD35 in both groups. There was a dose-dependent increase in PD3s after the two doses of atropine, but no significant difference in bronchodilatation between doses. Mean steepest slope approximately doubled in these three sets of challenges. 6. Chlorpheniramine caused a small degree of bronchodilatation and there was a non-significant increase in mean PD3s and in mean steepest slope in both normal and asthmatic groups. 7. There was a positive linear correlation between starting sGaw and steepest slope in each group of premedicated challenges, such that when

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First Report of Amaranthus hybridus with Multiple Resistance to 2,4-D, Dicamba, and Glyphosate

Agronomy ◽

10.3390/agronomy8080140 ◽

2018 ◽

Vol 8 (8) ◽

pp. 140 ◽

Cited By ~ 8

Author(s):

Ignacio Dellaferrera ◽

Eduardo Cortés ◽

Elisa Panigo ◽

Rafael De Prado ◽

Pedro Christoffoleti ◽

...

Keyword(s):

Dose Response ◽

Shikimic Acid ◽

Multiple Resistance ◽

Agricultural Systems ◽

Amaranthus Hybridus ◽

First Report ◽

Resistant Population ◽

Acid Accumulation ◽

Invasive Capacity

In many countries, Amaranthus hybridus is a widespread weed in agricultural systems. The high prolificacy and invasive capacity as well as the resistance of some biotypes to herbicides are among the complications of handling this weed. This paper reports on the first A. hybridus biotypes with resistance to auxinic herbicides and multiple resistance to auxinic herbicides and the EPSPs inhibitor, glyphosate. Several dose response assays were carried out to determine and compare sensitivity of six population of A. hybridus to glyphosate, 2,4-D, and dicamba. In addition, shikimic acid accumulation and piperonil butoxide effects on 2,4-D and dicamba metabolism were tested in the same populations. The results showed four populations were resistant to dicamba and three of these were also resistant to 2,4-D, while only one population was resistant to glyphosate. The glyphosate-resistant population also showed multiple resistance to auxinic herbicides. Pretreatment with piperonil butoxide (PBO) followed by 2,4-D or dicamba resulted in the death of all individual weeds independent of herbicide or population.

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Confirmation and Control of Annual Bluegrass (Poa annua) with Resistance to Prodiamine and Glyphosate

Weed Technology ◽

10.1614/wt-d-16-00084.1 ◽

2017 ◽

Vol 31 (1) ◽

pp. 111-119 ◽

Cited By ~ 7

Author(s):

Shane M. Breeden ◽

James T. Brosnan ◽

Thomas C. Mueller ◽

Gregory K. Breeden ◽

Brandon J. Horvath ◽

...

Keyword(s):

Dose Response ◽

Shikimic Acid ◽

Golf Course ◽

Multiple Resistance ◽

Post Dose ◽

Annual Bluegrass ◽

Resistant Phenotype ◽

Dry Biomass ◽

Herbicide Mixtures ◽

And Control

Poor annual bluegrass control was reported in golf course roughs following treatment with prodiamine (1120 gaiha−1) and glyphosate (840 gaeha−1) during hybrid bermudagrass dormancy. Research was conducted to determine if this annual bluegrass phenotype was resistant to both prodiamine and glyphosate and to determine the efficacy of herbicide mixtures for controlling this phenotype in the field. In PRE or POST dose-response experiments, 9 to 31 times more prodiamine or glyphosate was needed to control (or reduce dry biomass of) this resistant phenotype by 50% compared to an herbicide-susceptible phenotype. Moreover, glyphosate-susceptible plants accumulated 50% more shikimic acid (898 mgkg−1) 6 d after treatment than those resistant to glyphosate (394 mgkg−1). October (fall) applications of herbicide mixtures containing trifloxysulfuron, simazine,S-metolachlor, or mesotrione controlled this resistant annual bluegrass phenotype 84 to 98% in April (spring), with no differences detected among treatments. Our findings document the second instance of annual bluegrass evolving multiple resistance in a managed turfgrass system. However, several herbicide mixtures can be used to effectively manage this resistant phenotype.

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Paraquat Resistance of Sumatran Fleabane (Conyza sumatrensis)

Planta Daninha ◽

10.1590/s0100-83582019370100018 ◽

2019 ◽

Vol 37 ◽

Cited By ~ 3

Author(s):

L.H.S. ZOBIOLE ◽

V.G.C. PEREIRA ◽

A.J.P. ALBRECHT ◽

R.S. RUBIN ◽

F.S. ADEGAS ◽

...

Keyword(s):

Dose Response ◽

Logistic Model ◽

Multiple Resistance ◽

Response Curves ◽

Resistance Factors ◽

First Case ◽

Conyza Bonariensis ◽

Western Area ◽

Paraquat Resistance ◽

Weed Resistance

ABSTRACT: In Brazil, some populations of Conyza bonariensis and C. canadensis are glyphosate resistant and there are populations of C. sumatrensis (Sumatran fleabane) presenting multiple resistance to both glyphosate and chlorimuron. During the 2014/2015 and 2015/2016 seasons, growers reported failures to control Sumatran fleabane with paraquat. This study investigated the potential of paraquat resistant Sumatran fleabane populations in Paraná state, Brazil. Populations with suspected paraquat resistance were tested in the field in 2016 season. In 2017, seeds from these populations were collected, sown and grown in a greenhouse. Paraquat dose-response curve experiments were performed in Mogi Mirim, SP; Londrina, PR and Palotina, PR using doses of 0, 50, 100, 200, 400, 800, 1,600 and 3,200 g ha-1, following all standard criteria for confirmation of weed resistance cases. Percentage control was assessed at 3, 7, 14, 21 and 28 days after application and data were fitted to a nonlinear, log-logistic model, and dose response curves were generated. The results of this study confirmed significant levels of resistance of Sumatran fleabane biotypes to paraquat with resistance factors between 3,57 to 34,29. Therefore, the first case of C. sumatrensis resistance to paraquat was confirmed in biotypes from the western area of Paraná state, Brazil.

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STUDIES ON THE MOUSE UTERINE AUGMENTATION TEST FOR THE ASSAY OF FOLLICLE-STIMULATING HORMONE IN FOUR MOUSE COLONIES

Acta Endocrinologica ◽

10.1530/acta.0.0680715 ◽

1971 ◽

Vol 68 (4) ◽

pp. 715-724

Author(s):

D. W. Christie ◽

E. T. Bell ◽

D. Harrison

Keyword(s):

Dose Response ◽

Regression Coefficient ◽

Follicle Stimulating Hormone ◽

Human Chorionic Gonadotrophin ◽

National Institutes Of Health ◽

Strain Variation ◽

Linear Regression Coefficient ◽

Response Curves ◽

Different Doses ◽

Stimulating Hormone

ABSTRACT Assays of follicle-stimulating hormone from the National Institutes of Health (NIH-FSH-S4) have been conducted using the uterine augmentation test in four strains of mice. Dose response curves were determined for each strain using dosages of NIH-FSH ranging from 4–64 μg together with 0.1 IU human chorionic gonadotrophin (HCG) in five sc injections given over three days. The specificity of the assay was investigated in each strain by adding 2, 10 and 50 μg luteinizing hormone (NIH-LH-S6) to each of three doses of NIH-FSH, 6, 12 and 24 μg, forming a complete three factor experimental design; each mouse also received 0.1 IU HCG. Five mice from each strain were employed at each of the 64 treatment combinations. Values for b and λ in the dose response studies were acceptable for quantitative work but all strains were relatively insensitive. In the specificity studies the analysis of variance showed that a marked strain variation existed in the magnitude of the response to NIH-FSH and to NIH-LH while one strain showed a significant interaction between these two hormones. Regression analysis was carried out and the influence of different doses of NIH-LH on the linear regression coefficient was examined. In general it was considered that, under the conditions employed, none of the four strains would prove useful in the uterine augmentation test.

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Confirmation of Multiple Resistant Chloris radiata Population, Harvested in Colombian Rice Fields

Agronomy ◽

10.3390/agronomy11030496 ◽

2021 ◽

Vol 11 (3) ◽

pp. 496

Author(s):

Verónica Hoyos ◽

Guido Plaza ◽

José G. Vázquez-Garcia ◽

Candelario Palma-Bautista ◽

Antonia M. Rojano-Delgado ◽

...

Keyword(s):

Dose Response ◽

Weed Management ◽

Shikimic Acid ◽

Lethal Dose ◽

Dry Weight ◽

Integrated Weed Management ◽

Cross Resistance ◽

Multiple Resistance ◽

Visual Evaluation ◽

Acid Accumulation

This paper reports the first C. radiata population with resistance to glyphosate and multiple resistance to the acetolactate synthase (ALS) inhibitor, imazamox. Two populations, one putative resistant (R) and one susceptible (S), were used in the studies. Dose–response experiments were performed to evaluate the resistance factor (RF). Shikimic acid accumulation, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) and ALS enzyme activities were studied together with chemical integrated weed management (adjuvants and alternative herbicides). The resistance to glyphosate and imazamox was confirmed based on the dry weight reduction, visual evaluation and survival. The results of dose–response curve assays showed for the R population intermedium RF for glyphosate (5.1 and 9.7 for amount of herbicide needed to reduce the dry weight by 50% GR50 and lethal dose of 50% LD50, respectively) and high RF for imazamox (34.9 and 37.4, respectively). The low shikimic acid accumulation in R population confirmed the glyphosate resistance. The glyphosate concentration which inhibited the EPSPS enzyme in 50% (I50) was approximately 20 times higher for R population than the S population, while the imazamox I50 in ALS enzyme for the R plants was 89 times greater than the S plants. In the chemical integrated weed management, the foliar retention and effectivity assays showed that the use of adjuvants improves the retention of glyphosate and imazamox, and the reduction in dry weight of weeds. The alternative herbicides study showed that the acetyl-CoA carboxylase (ACCase) inhibitors, paraquat and glufosinate, had better results for control in this species. However, poor control was observed with bispyribac-sodium, metsulfuron-methyl and quinclorac, indicating possible cross-resistance for ALS-inhibitors and also multiple resistance for auxinic herbicides (quinclorac). Nevertheless dose–response experiments are required to confirm this assumption.

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First case of Conyza canadensis from Hungary with multiple resistance to glyphosate and flazasulfuron

10.20944/preprints201807.0199.v1 ◽

2018 ◽

Author(s):

Candelario Palma-Bautista ◽

Behroz Khalil Tahmasebi ◽

Pablo Tomás Fernández-Moreno ◽

Antonia María Rojano-Delgado ◽

Ricardo Alcántara de la Cruz ◽

...

Keyword(s):

Dose Response ◽

Shikimic Acid ◽

Multiple Resistance ◽

Conyza Canadensis ◽

Herbicide Application ◽

Susceptible Population ◽

First Case ◽

Acid Accumulation ◽

Agricultural Areas ◽

Als Inhibitor

Conyza canadensis is a species invading large agricultural areas throughout the world, mainly to its ability to evolve herbicide resistance. Specifically, in Hungary, extensive areas have been infested by this species due to the difficulty in controlling it with glyphosate. To corroborate this fact as resistance and not as an incorrect herbicide application, eight suspicious glyphosate-resistant C. canadensis populations from different Hungarian regions were studied. In dose-response assays with glyphosate, the LD50 and GR50 values indicated that populations 1 to 5 were resistant to this herbicide (H-5 population the most resistant). Besides, the shikimic acid accumulation tests corroborated the results observed in the dose-response assays. 11 alternative herbicides from 6 different mode of action (MOA) were applied at field doses as control alternatives on populations H-5 and H-6 (both in the same regions). The H-5 population showed an unexpected resistance to flazasulfuron (ALS-inhibitor). The ALS enzyme activity studies indicated that the I50 for H-5 was 63.3 fold higher compared to its correspondent susceptible population (H-6). Therefore, the H-5 population exhibited multiple-resistance to flazasulfuron and glyphosate, being the first case reported in Europe for this two MOA. For that reason, the other herbicides with different MOA have to be tested here.

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Are There Thresholds in Glioblastoma Cell Death Responses Triggered by Temozolomide?

International Journal of Molecular Sciences ◽

10.3390/ijms20071562 ◽

2019 ◽

Vol 20 (7) ◽

pp. 1562 ◽

Cited By ~ 8

Author(s):

Yang He ◽

Bernd Kaina

Keyword(s):

Dna Damage ◽

Dose Response ◽

P53 Protein ◽

Dose Range ◽

Dependent Manner ◽

Response Curves ◽

Damage Level ◽

Therapeutic Implications ◽

Linear Dose ◽

Different Doses

Temozolomide (TMZ) is an alkylating agent used in the treatment of high-grade malignant glioma, notably glioblastoma multiforme, the most aggressive form of brain cancer. The drug induces a dozen DNA methylation adducts, including O6-methylguanine (O6MeG), which is the most toxic primary DNA lesion as it causes the formation of DNA double-strand breaks (DSBs) that trigger apoptosis. In p53 wild-type cells, TMZ activates p-p53ser15 and p-p53ser46, which have opposing dual functions regulating survival and death, respectively. Since the use of TMZ in a therapeutic setting is limited because of its side effects, the question arises as to the existence of threshold doses that activate the death pathway and start apoptosis. To determine whether there is a threshold for the TMZ-induced DNA damage response and exploring the factors regulating the switch between p53 dependent survival and death, the glioblastoma lines LN-229 (deficient in MGMT) and LN-229MGMT (stably transfected with MGMT) were exposed to different doses of TMZ. p53 protein expression and phosphorylation levels of p-p53ser15 and p-p53ser46 were determined by Western blotting. Also, apoptosis, senescence and autophagy levels were checked after different doses of TMZ. The results show that pro-survival p-p53ser15 and pro-death p-p53ser46 were induced by O6MeG in a specific dose- and time-dependent manner. p-p53ser15 was an early response while p-p53ser46 was activated at later times following treatment. Unexpectedly, the dose-response curves for total p53, p-p53ser15 and p-p53ser46 were linear, without an obvious threshold. O6MeG induces apoptosis late after treatment as a linear function of TMZ dose. This was observed for both p53 proficient LN-229 and p53 lacking LN-308 cells. A linear dose-response after TMZ was also observed for senescence and autophagy as well as γH2AX, an indicator of DSBs that are considered to be the downstream trigger of apoptosis, senescence and autophagy. LN-229MGMT cells were highly resistant to all measured endpoints because of repair of the critical primary lesion. Although LN-308 were less responsive than LN-229 to TMZ, they displayed the same TMZ-induced DSB level. The observed linear dose-responses are not compatible with the view that low DNA damage level evokes survival while high damage level activates death functions. The data bear important therapeutic implications as they indicate that even low doses of TMZ may elicit a cytotoxic response. However, since O6MeG triggers apoptosis, senescence and autophagy in the same dose range, it is likely that the accumulation of senescent cells in the population counteracts the killing effect of the anticancer drug.

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First Case of Conyza canadensis from Hungary with Multiple Resistance to Glyphosate and Flazasulfuron

Agronomy ◽

10.3390/agronomy8080157 ◽

2018 ◽

Vol 8 (8) ◽

pp. 157 ◽

Cited By ~ 6

Author(s):

Candelario Palma-Bautista ◽

Behroz Khalil Tahmasebi ◽

Pablo Tomás Fernández-Moreno ◽

Antonia M. Rojano-Delgado ◽

Ricardo Alcántara de la Cruz ◽

...

Keyword(s):

Dose Response ◽

Shikimic Acid ◽

Multiple Resistance ◽

Conyza Canadensis ◽

Poor Control ◽

Susceptible Population ◽

First Case ◽

Whole Plant ◽

Acid Accumulation ◽

Als Inhibitor

Conyza canadensis is a species invading large areas throughout the world, mainly due to its ability to evolve herbicide resistance. In Hungary, extensive areas have been infested by this species due to the difficulty in controlling it with glyphosate. To determine whether poor control was a result of misapplication or glyphosate resistance, eight suspected glyphosate-resistant C. canadensis populations from different Hungarian regions were studied. In whole-plant dose-response assays with glyphosate, the LD50 and GR50 values (survival and fresh weight reduction at 50% relative to the untreated control, respectively) indicated that resistance was confirmed in five of the eight populations (H-5 population being the most resistant). Additionally, the shikimic acid accumulation tests corroborated the results observed in the dose–response assays. 11 alternative herbicides from six different modes of action (MOA) were applied at field doses as control alternatives on populations H-5 and H-6 (both in the same regions). The H-5 population showed an unexpected resistance to flazasulfuron (ALS-inhibitor). The ALS enzyme activity studies indicated that the I50 for H-5 with flazasulfuron was 63.3 times higher compared to its correspondent susceptible population (H-6). Therefore, the H-5 population exhibited multiple-resistance to flazasulfuron and glyphosate, being the first case reported in Europe for these two MOA.

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Dose-response Curves in the Fibrin Plate Assay Fibrinolytic Activity of Proteases

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647705 ◽

1974 ◽

Vol 32 (02/03) ◽

pp. 356-365 ◽

Cited By ~ 12

Author(s):

F Haverkate ◽

D. W Traas

Keyword(s):

Dose Response ◽

Fibrinolytic Activity ◽

Enzyme Concentration ◽

Response Curves ◽

Agar Gel ◽

Porcine Tissue ◽

Plate Assay ◽

Fibrin Plate ◽

Different Types ◽

Dose Response Curves

SummaryIn the fibrin plate assay different types of relationships between the dose of applied proteolytic enzyme and the response have been previously reported. This study was undertaken to determine whether a generally valid relationship might exist.Trypsin, chymotrypsin, papain, the plasminogen activator urokinase and all of the microbial proteases investigated, including brinase gave a linear relationship between the logarithm of the enzyme concentration and the diameter of the circular lysed zone. A similar linearity of dose-response curves has frequently been found by investigators who used enzyme plate assays with substrates different from fibrin incorporated in an agar gel. Consequently, it seems that this linearity of dose-response curves is generally valid for the fibrin plate assay as well as for other enzyme plate bioassays.Both human plasmin and porcine tissue activator of plasminogen showed deviations from linearity of semi-logarithmic dose-response curves in the fibrin plate assay.

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