Analysis of Point Mutations Associated with Resistance and Acaricides Selection for Control of Field-collected Populations in Two-spotted Mites, Tetranychus urticae (Acari: Tetranychidae)

2021 ◽  
Vol 25 (3) ◽  
pp. 177-187
Author(s):  
Eungyeong Shin ◽  
Sun-Ran Cho ◽  
Yeol-Gyu Kang ◽  
Hyun Kyung Kim ◽  
Hyun-Na Koo ◽  
...  
Keyword(s):  
Tetranychus Urticae ◽  
Point Mutations ◽  
Selection For

Selection, adaptation, and bacterial operons

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 265-271 ◽  
Author(s):  
Barry G. Hall
Keyword(s):  
Structural Gene ◽  
Point Mutations ◽  
Gene Mutations ◽  
Adaptive Mutation ◽  
Evolutionary Potential ◽  
Adaptive Mutations ◽  
Metabolic Functions ◽  
Metabolic Capability ◽  
Regulatory Mutations ◽  
Selection For

Bacteria are especially useful as systems to study the molecular basis of adaptive evolution. Selection for novel metabolic capabilities has allowed us to study the evolutionary potential of organisms and has shown that there are three major "strategies" for the evolution of new metabolic functions. (i) Regulatory mutations may allow a gene to be expressed under unusual conditions. If the product ofthat gene is already active toward a novel resource, then a regulatory mutation alone may confer a new metabolic capability. (ii) Structural gene mutations may alter the catalytic properties of enzymes so that they can act on novel substrates. These structural gene mutations may dramatically improve catalytic capabilities, and in some cases they can confer entirely new capabilities upon enzymes. In most cases both regulatory and structural gene mutations are required for the effective evolution of new metabolic functions. (iii) Operons that are normally silent, or cryptic, may be activated by either point mutations or by the action of mobile genetic elements. When activated, these operons can provide entirely new pathways for the metabolism of novel resources. Selection can also play a role in modulating the probability that a particular adaptive mutation will occur. In this paper I present evidence that a specific adaptive mutation, reversion of the metB1 mutation, occurs 60 to 80 times more frequently during prolonged selection on plates under conditions where the members of the population are not growing than it does in growing cells under nonselective conditions. This selective condition, methionine starvation, does not increase the frequency of other mutations unrelated to methionine biosynthesis. Thus, contrary to our present notions, selection can act not only to reveal preexisting mutations but to modulate the frequency with which adaptive mutations occur.Key words: mutation rates, molecular evolution, adaptive mutations, cryptic genes.

Novel imatinib-sensitive PDGFRA-activating point mutations in hypereosinophilic syndrome induce growth factor independence and leukemia-like disease

Blood ◽  
2011 ◽  
Vol 117 (10) ◽  
pp. 2935-2943 ◽  
Author(s):  
Christian Elling ◽  
Philipp Erben ◽  
Christoph Walz ◽  
Marie Frickenhaus ◽  
Mirle Schemionek ◽  
...  
Keyword(s):  
Growth Factor ◽  
Hypereosinophilic Syndrome ◽  
Point Mutations ◽  
Imatinib Treatment ◽  
Presumptive Diagnosis ◽  
Activating Mutations ◽  
Transforming Activity ◽  
Selection For ◽  
Constitutive Phosphorylation

Abstract The FIP1L1-PDGFRA fusion is seen in a fraction of cases with a presumptive diagnosis of hypereosinophilic syndrome (HES). However, because most HES patients lack FIP1L1-PDGFRA, we studied whether they harbor activating mutations of the PDGFRA gene. Sequencing of 87 FIP1L1-PDGFRA–negative HES patients revealed several novel PDGFRA point mutations (R481G, L507P, I562M, H570R, H650Q, N659S, L705P, R748G, and Y849S). When cloned into 32D cells, N659S and Y849S and—on selection for high expressors—also H650Q and R748G mutants induced growth factor–independent proliferation, clonogenic growth, and constitutive phosphorylation of PDGFRA and Stat5. Imatinib antagonized Stat5 phosphorylation. Mutations involving positions 659 and 849 had been shown previously to possess transforming potential in gastrointestinal stromal tumors. Because H650Q and R748G mutants possessed only weak transforming activity, we injected 32D cells harboring these mutants or FIP1L1-PDGFRA into mice and found that they induced a leukemia-like disease. Oral imatinib treatment significantly decreased leukemic growth in vivo and prolonged survival. In conclusion, our data provide evidence that imatinib-sensitive PDGFRA point mutations play an important role in the pathogenesis of HES and we propose that more research should be performed to further define the frequency and treatment response of PDGFRA mutations in FIP1L1-PDGFRA–negative HES patients.

scholarly journals Teicoplanin Stress-Selected Mutations Increasing ςB Activity in Staphylococcus aureus

2001 ◽  
Vol 45 (6) ◽  
pp. 1714-1720 ◽  
Author(s):  
Markus Bischoff ◽  
Brigitte Berger-Bächi
Keyword(s):  
Staphylococcus Aureus ◽  
Target Genes ◽  
Point Mutations ◽  
Pigment Formation ◽  
Genetic Manipulations ◽  
Alternative Transcription ◽  
Selection For ◽  
Dehydrosqualene Synthase ◽  
Promoter Mutations ◽  
Orange Color

ABSTRACT A natural rsbU mutant of Staphylococcus aureus, unable to activate the alternative transcription factor ςB via the RsbU pathway and therefore forming unpigmented colonies, produced first-step teicoplanin-resistant mutants upon selection for growth in the presence of teicoplanin, of which the majority were of an intense orange color. By using an asp23promoter-luciferase fusion as an indicator, the pigmented mutants were shown to express increased ςB activity. Increased ςB activity was associated with point mutations inrsbW, releasing ςB from sequestration by the anti-sigma factor RsbW, or to promoter mutations increasing the ςB/RsbW ratio. Genetic manipulations involving thesigB operon suggested that the mutations within the operon were associated with the increase in teicoplanin resistance. The upregulation of ςB suggests that a ςB-controlled gene(s) is directly or indirectly involved in the development of teicoplanin resistance in S. aureus. Carotenoids do not contribute to teicoplanin resistance, since inactivation of the dehydrosqualene synthase gene crtMabolished pigment formation without affecting teicoplanin resistance. The relevant ςB-controlled target genes involved in teicoplanin resistance remain to be identified.

scholarly journals Somatic cell selection for chlorsulfuron-resistant mutants in potato: identification of point mutations in the acetohydroxyacid synthase gene

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Philippa J. Barrell ◽  
Julie M. Latimer ◽  
Samantha J. Baldwin ◽  
Michelle L. Thompson ◽  
Jeanne M.E. Jacobs ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Point Mutations ◽  
Acetohydroxyacid Synthase ◽  
Cell Selection ◽  
Resistant Mutants ◽  
Selection For

scholarly journals Acetylcholinesterase point mutations in European strains of Tetranychus urticae (Acari: Tetranychidae) resistant to organophosphates

2009 ◽  
Vol 66 (2) ◽  
pp. 220-228 ◽  
Author(s):  
Jahangir Khajehali ◽  
Thomas Van Leeuwen ◽  
Maria Grispou ◽  
Evangelia Morou ◽  
Haoués Alout ◽  
...  
Keyword(s):  
Tetranychus Urticae ◽  
Point Mutations

scholarly journals Selection for functional diversity drives accumulation of point mutations in Dr adhesins of Escherichia coli

2007 ◽  
Vol 64 (1) ◽  
pp. 180-194 ◽  
Author(s):  
Natalia Korotkova ◽  
Sujay Chattopadhyay ◽  
Tami A. Tabata ◽  
Viktoria Beskhlebnaya ◽  
Vladimir Vigdorovich ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Functional Diversity ◽  
Point Mutations ◽  
Selection For

scholarly journals Target-Site Mutations and Glutathione S-Transferases Are Associated with Acequinocyl and Pyridaben Resistance in the Two-Spotted Spider Mite Tetranychus urticae (Acari: Tetranychidae)

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 511 ◽  
Author(s):  
Jihye Choi ◽  
Hyun-Na Koo ◽  
Sung Il Kim ◽  
Bueyong Park ◽  
Hyunkyung Kim ◽  
...  
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Point Mutations ◽  
Cross Resistance ◽  
Glutathione S Transferase ◽  
Short Life ◽  
Resistance Development ◽  
Glutathione S Transferases ◽  
Two Spotted Spider Mite ◽  
Gst Activity

The two-spotted spider mite Tetranychus urticae is a difficult-to-control pest due to its short life cycle and rapid resistance development. In this study, we characterized field strains collected in 2001 and 2003 that were selected for acequinocyl resistance (AR) and pyridaben resistance (PR), respectively. These strains displayed resistance ratios of 1798.6 (susceptible vs. AR) and 5555.6 (susceptible vs. PR), respectively, and were screened for cross-resistance against several currently used acaricides. The AR strain exhibited pyridaben cross-resistance, but the PR strain showed no cross-resistance. The AR strain exhibited point mutations in cytb (I256V, N321S) and PSST (H92R). In contrast, the PR strain exhibited the H92R but not the I256V and N321S point mutations. In some cases increased glutathione S-transferase (GST) activity has previously been linked to enhanced detoxification. The AR strain exhibited approximately 2.3-, 1.8-, and 2.2-fold increased GST activity against 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), and 4-nitrobenzyl chloride (NBC), respectively. Among the five GST subclass genes (delta, omega, mu, zeta, and kappa), the relative expression of delta class GSTs in the AR strain were significantly higher than the PR and susceptible strain. These results suggest that the I256V and N321S mutations and the increased GST metabolism and GST delta overexpression might be related to acequinocyl resistance in T. urticae.

scholarly journals Susceptibility to Acaricides and the Frequencies of Point Mutations in Etoxazole- and Pyridaben-Resistant Strains and Field Populations of the Two-Spotted Spider Mite, Tetranychus urticae (Acari: Tetranychidae)

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 660
Author(s):  
Hyun-Na Koo ◽  
Jihye Choi ◽  
Eungyeong Shin ◽  
Wonjin Kang ◽  
Sun-Ran Cho ◽  
...  
Keyword(s):  
Point Mutation ◽  
Tetranychus Urticae ◽  
High Frequency ◽  
Spider Mite ◽  
Point Mutations ◽  
Cross Resistance ◽  
Resistance Patterns ◽  
Resistant Strains ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

The two-spotted spider mite Tetranychus urticae Koch is a major agricultural pest worldwide and is known to rapidly develop resistance to pesticides. In the present study, we explored a field strain that was collected in 2000 and 2003 and has been exhibiting resistance to etoxazole and pyridaben over the last 16 years. The resistance ratios of the etoxazole- and pyridaben-resistant strains (ER and PR) to etoxazole or pyridaben were more than 5,000,000- and 4109.6-fold higher than that of the susceptible strain, respectively. All field-collected populations showed resistance to etoxazole and pyridaben. The ER and PR strains showed cross-resistance to several acaricides. Both I1017F and H92R point mutations were detected in 7 out of 8 field groups. Spirodiclofen and spiromesifen resulted in more than 77.5% mortality in the 8 field groups. In addition, the genotype frequency of the I1017F point mutation was 100.0% in the ER strain, and that of the H92R point mutation was 97.0% in the PR strain. All of the field populations were found to have a high frequency of I1017F. These results suggest that the observation of resistance patterns will help in designing a sustainable IPM program for T. urticae.

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