THE PRODUCTION OF A DDT-RESISTANT STRAIN OF AEDES AEGYPTI MARKED ON ALL THREE LINKAGE GROUPS

1974 ◽  
Vol 16 (4) ◽  
pp. 883-888 ◽  
Author(s):  
J. P. Margham ◽  
R. J. Wood
Keyword(s):  
Aedes Aegypti ◽  
Resistance Genes ◽  
Resistant Strain ◽  
Genetic Background ◽  
Adult Stage ◽  
Susceptible Strain ◽  
Linkage Studies ◽  
Linkage Groups ◽  
Resistant Strains ◽  
Major Resistance Genes

DDT-resistant strains marked on all three linkage groups have been produced by selection at the adult stage after outcrossing a resistant strain (BANGKOK-HR) to a marked susceptible strain (64). The most resistant and viable line (BANGKOK-MR) was kept for linkage studies. The production of a marked resistant strain was not entirely straightforward. In the absence of a suitable genetic background, major resistance genes conferred little or no DDT tolerance and could not be selected. Selection at the adult stage produced resistance in larvae as well as in adults. Resistance was achieved more rapidly in larvae than in adults

CROSSOVER VALUES BETWEEN DIELDRIN-RESISTANCE AND DDT-RESISTANCE AND LINKAGE-GROUP-2 GENES IN AEDES AEGYPTI

1970 ◽  
Vol 12 (3) ◽  
pp. 407-414 ◽  
Author(s):  
W. L. Lockhart ◽  
W. Klassen ◽  
A. W. A. Brown
Keyword(s):  
Linkage Group ◽  
Aedes Aegypti ◽  
Resistant Strain ◽  
Susceptible Strain ◽  
Total Distance ◽  
Resistant Strains ◽  
Ddt Resistance ◽  
Group 2

Crosses and backcrosses between five dieldrin-resistant strains and the MYS susceptible strain in Aedes aegypti indicate the order of the genes to be Dl—si — s, the distance si — s being 6-7 units and the total distance Dl — s being 25-31 units.Crosses between the Trinidad DDT-resistant strain and the MYS marker strain indicate the order to be si — s — DDT, the distance si — s being 4 units and the total distance s — DDT being 10 units. Crosses between this strain and the AO and Multiple marker strains indicate the order to be y — s — DDT.These results indicate that the order of the genes in linkage-group 2 of Aedes aegypti is probably Dl — si — y —s — DDT. The total crossover distance of some 45 units thus implied between Dl and DDT is, however, at variance with previous work which found the direct crossover between these two genes to be only 4-7%.

scholarly journals Polygenic and single gene responses to selection for resistance to diazinon in Lucilia cuprina.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 613-620 ◽  
Author(s):  
J A McKenzie ◽  
A G Parker ◽  
J L Yen
Keyword(s):  
Resistant Strain ◽  
Single Gene ◽  
Natural Populations ◽  
Susceptible Strain ◽  
Selection Line ◽  
Base Population ◽  
Gene Response ◽  
Biochemical Profiles ◽  
Resistant Strains ◽  
Selection For

Abstract Following mutagenesis with ethyl methanesulfonate, selection in a susceptible strain with a concentration of the insecticide diazinon (0.0004%, w/v) above that required to kill 100% of the susceptible strain, the LC100 of that strain, resulted in a single gene response. The resultant four mutant resistant strains have equivalent physiological, genetical and biochemical profiles to a diazinon-resistant strain derived from a natural population and homozygous for the Rop-1 allele. Modification of the microsomal esterase E3 is responsible for resistance in each case. The Rop-1 locus maps approximately 4.4 map units proximal to bu on chromosome IV. Selection within the susceptible distribution, at a concentration of diazinon [0.0001% (w/v)] less than the LC100, resulted in a similar phenotypic response irrespective of whether the base population had been mutagenized. The responses were polygenically based, unique to each selection line and independent of Rop-1. The relevance of the results to selection for insecticide resistance in laboratory and natural populations is discussed.

scholarly journals Failure of Permethrin-Treated Military Uniforms to Protect Against a Laboratory-Maintained Knockdown-Resistant Strain of Aedes aegypti

2020 ◽  
Vol 36 (2) ◽  
pp. 127-130
Author(s):  
Alden S. Estep ◽  
Neil D. Sanscrainte ◽  
Ingeborg Cuba ◽  
Gregory M. Allen ◽  
James J. Becnel ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Aedes Aegypti ◽  
Resistant Strain ◽  
Untreated Control ◽  
Pyrethroid Resistance ◽  
Disease Vectors ◽  
Significant Protection ◽  
Additional Testing ◽  
Resistant Strains ◽  
Preliminary Study

ABSTRACT Military forces and the recreational industry rely on the repellent properties of permethrin-treated fabrics and N,N-diethyl-meta-toluamide (deet)–based lotions to provide protection from disease vectors and hematophagous organisms. Concerns regarding efficacy have been raised as pyrethroid resistance becomes more common and recent publications present contradictory conclusions. In this preliminary study, consenting volunteers were exposed to pyrethroid-susceptible and pyrethroid-resistant Aedes aegypti strains while wearing sleeves of untreated or permethrin-treated army uniform fabric as well as with untreated or deet-treated exposed forearms. Deet was nearly 100% effective against both susceptible and resistant strains. However, permethrin treatment provided no significant protection against the resistant Puerto Rico strain relative to untreated control sleeves. These results confirm that pyrethroid-resistant vectors can negate the efficacy of permethrin-treated uniforms. Additional testing with resistant field strains is needed to better understand the risk to service members.

scholarly journals In vitro anti-mycobacterial activity of (E)-N´-(monosubstituted-benzylidene) isonicotinohydrazide derivatives against isoniazid-resistant strains

2012 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
Tatiane S. Coelho ◽  
Jessica B. Cantos ◽  
Marcelle L.F. Bispo ◽  
Raoni S.B. Gonçalves ◽  
Camilo H.S. Lima ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Resistant Strain ◽  
Mechanisms Of Action ◽  
Susceptible Strain ◽  
Clinical Isolates ◽  
Coding Region ◽  
Resistant Strains

A series of twenty-three <em>N-acylhydrazones</em> derived from isoniazid (INH 1-23) have been evaluated for their <em>in vitro</em> antibacterial activity against INH- susceptible strain of <em>M. tuberculosis</em> (RG500) and three INH-resistant clinical isolates (RG102, RG103 and RG113). In general, derivatives 4, 14, 15 and 16 (MIC=1.92, 1.96, 1.96 and 1.86 mM, respectively) showed relevant activities against RG500 strain, while the derivative 13 (MIC=0.98 mM) was more active than INH (MIC=1.14 mM). However, these derivatives were inactive against RGH102, which displays a mutation in the coding region of <em>inhA</em>. These results suggest that the activities of these compounds depend on the inhibition of this enzyme. However, the possibility of other mechanisms of action cannot be excluded, since compounds 2, 4, 6, 7, 12-17, 19, 21 and 23 showed good activities against <em>katG</em>-resistant strain RGH103, being more than 10-fold more active than INH.

Commensal Escherichia coli of healthy humans: a reservoir for antibiotic-resistance determinants

2010 ◽  
Vol 59 (11) ◽  
pp. 1331-1339 ◽  
Author(s):  
Jannine K. Bailey ◽  
Jeremy L. Pinyon ◽  
Sashindran Anantham ◽  
Ruth M. Hall
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Resistant Strain ◽  
Healthy Adults ◽  
Susceptible Strain ◽  
E Coli ◽  
Resistance Determinants ◽  
Healthy Humans ◽  
Depth Analysis

This study examined in detail the population structure of Escherichia coli from healthy adults with respect to the prevalence of antibiotic resistance and specific resistance determinants. E. coli isolated from the faeces of 20 healthy adults not recently exposed to antibiotics was tested for resistance to ten antibiotics and for carriage of integrons and resistance determinants using PCR. Strain diversity was assessed using biochemical and molecular criteria. E. coli was present in 19 subjects at levels ranging from 2.0×104 to 1.7×108 c.f.u. (g faeces)−1. Strains resistant to one to six antibiotics were found at high levels (>30 %) in only ten individuals, but at significant levels (>0.5 %) in 14. Resistant isolates with the same phenotype from the same individual were indistinguishable, but more than one susceptible strain was sometimes found. Overall, individuals harboured one to four E. coli strains, although in 17 samples one strain was dominant (>70 % of isolates). Eighteen strains resistant to ampicillin, sulfamethoxazole, tetracycline and trimethoprim in 15 different combinations were observed. One resistant strain was carried by two unrelated individuals and a susceptible strain was shared by two cohabiting subjects. Two minority strains were derivatives of a more abundant resistant strain in the same sample, showing that continuous evolution is occurring in vivo. The trimethoprim-resistance genes dfrA1, dfrA5, dfrA7, dfrA12 or dfrA17 were in cassettes in a class 1 or class 2 integron. Ampicillin resistance was conferred by the bla TEM gene, sulfamethoxazole resistance by sul1, sul2 or sul3 and tetracycline resistance by tetA(A) or tetA(B). Chloramphenicol resistance (cmlA1 gene) was detected only once. Phylogenetic groups A and B2 were more common than B1 and D. Commensal E. coli of healthy humans represent an important reservoir for numerous antibiotic-resistance genes in many combinations. However, measuring the true extent of resistance carriage in commensal E. coli requires in-depth analysis.

scholarly journals The influence of the y locus on DDT resistance in the mosquito Aedes aegypti L

1970 ◽  
Vol 16 (1) ◽  
pp. 37-47 ◽  
Author(s):  
R. J. Wood
Keyword(s):  
Linkage Group ◽  
Aedes Aegypti ◽  
Environmental Factor ◽  
Resistant Strain ◽  
Pleiotropic Effect ◽  
Susceptible Strain ◽  
Genetic Influences ◽  
Larval Diet ◽  
Ddt Resistance ◽  
Group Ii

SUMMARYThe influence of the linkage group II locus y on DDT resistance in Aedes aegypti has been studied in crosses between the Trinidad resistant strain and QS susceptible strain. The y locus influences DDT resistance in both R/R and R/+ larvae. The effect of y may be interpreted as reducing the penetrance of R (RDDT1), which is also located on linkage group II. y+ is partially dominant and incompletely penetrant in its resistance-enhancing role (although in its pleiotropic effect on larval colour it is dominant and fully penetrant). Penetrance of y+ is influenced by an environmental factor, probably associated with the larval diet.The effect of y on resistance is evaluated in relation to other genetic influences on the expression of RDDT1.The significance of polymorphism at the y locus is discussed.

Soybean cyst nematode: Challenges and opportunities

2006 ◽  
Vol 86 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Shawn M. J Winter ◽  
Istvan Rajcan ◽  
Barry J Shelp
Keyword(s):  
Resistance Genes ◽  
Soybean Cyst Nematode ◽  
Glycine Soja ◽  
Cyst Nematode ◽  
Infested Soil ◽  
Linkage Groups ◽  
Factors Affecting ◽  
Scn Resistance ◽  
Major Resistance Genes ◽  
Time Required

Soybean cyst nematode (SCN) is the primary pest responsible for yield losses of Glycine max. Management of SCN remains difficult in commercial soybean production due to the length of its biological cycle, frequent changes in population virulence, and ease of spread via infested soil. Effective management relies on crop rotation in combination with resistant cultivars, which have been derived from a limited germplasm base. Breeding for SCN resistance in soybean is difficult due to the quantitative nature of the trait, genetic variation within SCN populations, time required for phenotyping experimental soybean lines, and environmental factors affecting SCN reproduction. Quantitative trait loci associated with SCN resistance have been identified on 17 of the 20 soybean linkage groups, explaining 1–91% of the total phenotypic variation. Two major resistance genes, rhg 1 and Rhg 4, have been identified on linkage groups G and A2, respectively. Several minor resistance genes have been identified, but their importance varies with germplasm source and nematode race. Enhancement of SCN resistance in G. max may be achieved by interspecific hybridization with G. soja, the wild ancestor, or by engineering plants with candidate resistance genes such as Hs1pro-1. Key words: Genetic engineering, Glycine soja, soybean cyst nematode, molecular markers, resistance

Comparisons Between the Response of German Cockroach Field-Collected Strains (Dictyoptera: Blattellidae) to Vapors and Contact with a Cyfluthrin Formulation

1993 ◽  
Vol 28 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Mary H. Ross
Keyword(s):  
Resistant Strain ◽  
German Cockroach ◽  
Susceptible Strain ◽  
Late Instar ◽  
Resistant Strains ◽  
Biochemical Resistance

Research on differences in insecticide-induced behavior of German cockroach field-collected strains was continued. Late instar nymphs (5th–6th stadia) were drawn from the Fairbanks, an insecticide susceptible strain, and two pyrethroid resistant strains, the Jacksonville and Forest Green. Dispersal induced by vapors of a cyfluthrin flowable concentrate (FC) and the FC formulation base (blank) was compared with response to the FC and the FC blank when dry. Jacksonville nymphs avoided the dried FC, but not as strongly as Fairbanks strain nymphs. The Al played a major role in eliciting avoidance by Fairbanks strain nymphs but, in the Jacksonville strain, avoidance was due more to an ingredient(s) of the formulation base. Forest Green nymphs did not avoid the dried FC or the FC blank. Vapors of the FC and the FC blank caused rapid dispersal of all strains, but dispersal of resistant strain nymphs was slower than that of susceptible strain nymphs. Although Jacksonville nymphs responded more strongly to the dried formulation than Forest Green nymphs, the response to vapors was weaker than that of Forest Green nymphs. It is suggested that localized populations of the German cockroach have developed many different combinations of behavioral modifications and physiological/biochemical resistance.

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