scholarly journals HIV and the CCR5-Δ32 resistance allele

2004 ◽  
Vol 241 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Eric Silva ◽  
Michael P.H. Stumpf
Keyword(s):  
Resistance Allele ◽  
I 32

scholarly journals Estimation of Cry3Bb1 resistance allele frequency in field populations of western corn rootworm using a genetic marker

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alan Willse ◽  
Lex Flagel ◽  
Graham Head
Keyword(s):  
Allele Frequency ◽  
Western Corn Rootworm ◽  
Allele Frequencies ◽  
Chromosome 8 ◽  
Corn Belt ◽  
Corn Rootworm ◽  
Resistance Allele ◽  
Response To Selection ◽  
The Us ◽  
Causal Allele

Abstract Following the discovery of western corn rootworm (WCR; Diabrotica virgifera virgifera) populations resistant to the Bacillus thuringiensis (Bt) protein Cry3Bb1, resistance was genetically mapped to a single locus on WCR chromosome 8 and linked SNP markers were shown to correlate with the frequency of resistance among field-collected populations from the US Corn Belt. The purpose of this paper is to further investigate the relationship between one of these resistance-linked markers and the causal resistance locus. Using data from laboratory bioassays and field experiments, we show that one allele of the resistance-linked marker increased in frequency in response to selection, but was not perfectly linked to the causal resistance allele. By coupling the response to selection data with a genetic model of the linkage between the marker and the causal allele, we developed a model that allowed marker allele frequencies to be mapped to causal allele frequencies. We then used this model to estimate the resistance allele frequency distribution in the US Corn Belt based on collections from 40 populations. These estimates suggest that chromosome 8 Cry3Bb1 resistance allele frequency was generally low (<10%) for 65% of the landscape, though an estimated 13% of landscape has relatively high (>25%) resistance allele frequency.

Organophosphorus insecticide resistance in a new strain of Culex quinquefasciatus (Diptera: Culicidae) from Tanga, Tanzania

1993 ◽  
Vol 83 (1) ◽  
pp. 67-74 ◽  
Author(s):  
A. Khayrandish ◽  
R.J. Wood
Keyword(s):  
Insecticide Resistance ◽  
Culex Quinquefasciatus ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Laboratory Culture ◽  
Fourth Instar ◽  
Resistance Allele ◽  
Susceptible Control ◽  
The Mean

AbstractFourth instar larvae of a new strain of Culex quinquefasciatus Say from Tanzania (TANGA) were tested for insecticide resistance. Initially, the resistance ratio (RR) to chlorpyrifos was 41.8, to temephos 30.8, to propoxur 3.7. After 2–3 years of laboratory culture, resistance to chlorpyrifos and propoxur had declined (chlorpyrifos 5.7, 3.8; propoxur 1.9, permethrin 1.9). Significant synergism was found between s, s, s-tributyl trithiophosphate (DEF) and chlorphyrifos, reducing the RR from 8.0 to 2.5. Synergism between piperonyl butoxide and permethrin was less than in a susceptible control strain. Twelve esterase isozymes of different relative mobilities (Rm) on polyacrylamide gel electrophoresis were identified, ten of which remained when the strain was reinvestigated two years (approximately 32 generations) later. Null activity for all but one of these bands was observed in some larvae. Four esterase bands (Rm 0.25, 0.27, 0.31, 0.34, designated A2, A3, B2, B3) showed polymorphism in activity, with very intense bands in some larvae. The mean frequency of bands with activity greater than standard, declined as organophosphorus (OP) resistance declined, but resistance was unconnected with the frequency of nulls at these positions. In mass larval assays of in vitro sensitivity of acetylcholinesterase (AChE) to propoxur, the I50 exceeded 10x10−4M, compared with 0.1x10−4M in a reverted resistant strain (RANGOON). Single larvel assays revealed heterogeneity, which was interpreted on the basis of an AChE resistance allele (AceR) with a frequency of 0.23.

scholarly journals Segregation for Resistance to Eastern Filbert Blight in Progeny of `Zimmerman' Hazelnut

2006 ◽  
Vol 131 (6) ◽  
pp. 731-737 ◽  
Author(s):  
China F. Lunde ◽  
Shawn A. Mehlenbacher ◽  
David C. Smith
Keyword(s):  
Rapd Markers ◽  
Chromosome Region ◽  
Random Amplified Polymorphic Dna ◽  
Rapd Marker ◽  
Segregation Ratio ◽  
Enzyme Linked Immunosorbent Assay ◽  
Resistance Locus ◽  
Resistance Allele ◽  
Reciprocal Translocations ◽  
Eastern Filbert Blight

Eastern filbert blight (EFB), caused by the fungus Anisogramma anomala (Peck) E. Müller, is an important disease of european hazelnut (Corylus avellana L.) in the Pacific northwestern United States. In 1989, a chance seedling free of EFB was discovered adjacent to a severely diseased orchard near Troutdale, Ore. This selection, subsequently named `Zimmerman', was crossed with three susceptible selections. Based on morphological characters and incompatibility alleles, we speculated that `Zimmerman' (S1 S3) was a hybrid between `Barcelona' (S1 S2) and `Gasaway' (S3 S26). The three seedling populations were inoculated with spores of the pathogen in a greenhouse test and assayed by indirect enzyme-linked immunosorbent assay (ELISA) and by observation of canker incidence. The observed segregation fit a 3 resistant : 1 susceptible ratio in all three progenies, in contrast to the 1 : 1 ratio found when the resistant pollinizer `Gasaway' was crossed to susceptible genotypes. Random amplified polymorphic DNA (RAPD) marker UBC 152800 linked to the resistance gene in `Gasaway' co-segregated with the resistant phenotype in all three populations with 2%, 4%, and 6% recombination, respectively. Seed germination and transplanting records did not provide evidence of selection in favor of resistant seedlings. Pollen germination was 71% in `Gasaway', 29% in `Zimmerman', and 18% in `Barcelona', indicating possible selection at the gametophytic level. Subsequently 16 resistant seedlings of `Zimmerman' were crossed with the highly susceptible selection OSU 313.078. Segregation fit a 3 : 1 ratio in 14 of the 16 progenies, and showed a surplus of resistant seedlings in the other two. None showed a 1 : 1 segregation. Resistance co-segregated with two RAPD markers that flank the `Gasaway' resistance allele. To test allelism of resistance from `Gasaway' and `Zimmerman', VR 6-28 with resistance from `Gasaway' was crossed with `Zimmerman'. Eight resistant selections from this progeny were crossed with OSU 313.078. Five of the eight progenies segregated 3 : 1, two progenies segregated 1 : 1, and OSU 313.078 × OSU 720.056 gave only resistant offspring. The ratios indicate that OSU 720.056 is homozygous resistant and that `Zimmerman' and `Gasaway' share a common resistance allele. Reciprocal translocations have been reported in hazelnut cultivars, including `Barcelona', the leading cultivar in Oregon. `Zimmerman' appears to be a hybrid of `Barcelona' and `Gasaway', but because of cytogenetic abnormalities, `Zimmerman' may have inherited two copies of the chromosome region that contain the resistance locus and flanking RAPD markers. If the region containing the resistance were attached to two independent centromeres, a 3 : 1 segregation ratio for disease response and flanking markers would be expected, and we propose this as the most likely explanation. Resistance from `Gasaway' and `Zimmerman' has been called “immunity” or “complete resistance.” However, we noted a few seedlings with small cankers, nearly all of which lacked sporulating stromata. Flanking RAPD markers indicate that the resistance allele is present in these seedlings. Although not “immune” or “completely resistant,” `Gasaway' and `Zimmerman' transmit a very high level of resistance.

scholarly journals Piezohirurška ekspanzija alveolarnih grebenova u svrhu imedijatne ugradnje dentalnih implantata

2015 ◽  
Vol 9 (1) ◽  
Author(s):  
Nenad Tanasković ◽  
Miroslav Lučić ◽  
Ranko Popović
Keyword(s):  
I 32

Uvod. Dugogodišnja bezubost dovodi do znatne atrofije alveolarnih grebenovašto zbrinjavanje ove bezubosti dentalnim implantatima čini velikim izazovom.Kod pacijenata koji bi bezubost rešavali implantatima, a volumen kosti to nedozvoljava, najčešće se predlaže korekcija grebena vođenom koštanom regeneracijomili slobodnim koštanim transplantatima. Širenje grebenova u svrhupripreme ležišta za prijem implantata predstavlja praktično jedinu opciju zaimedijatno zbrinjavanje ovih pacijenata, a to je uz poštedu koštanih strukturabilo praktično nemoguće do pojave piezo uređaja. Cilj rada je bio ispitatiefekte primene piezohirurških osteotomija i širenja grebenova dletom kakobi se dobio odgovarajući prostor za imedijatnu implantaciju kod pacijenatakoji nisu prihvatili predloženu rekonstrukciju uskih grebenova slobodnimkoštanim transplantatima.Metode. Tretirana su 32 pacijenta, 18 žena i 14 muškaraca prosečne starosti 40godina. Svim pacijentima je kao jedino rešenje za korekciju uskih grebenovapredložena rekonstrukcija slobodnim koštanim transplantatima što su oniodbili. Plasirano je 96 implantata prečnika 3,3 mm i 3,6 mm i dužine 10 mmi 12 mm, od toga 64 u gornjoj vilici i 32 u donjoj vilici. Svim pacijentima je upripremnom periodu urađen ortopantomogram i konbim kompjuterizovanatomografija, kako bi se, pre svega, konstatovalo da li između čvrstih koštanihlamela postoji spongioza.Rezultati. Ukupan zbir dobijenih širina nakon osteotomija merenih kaliperomje bio od 5 do 7 mm, sa srednjom vrednošću od 6 mm. Gubitak visine alveolarnekosti je prema Buzerovim kriterijumima bio 0,81±0,31 mm mezijalno i0,67±0,37 mm distalno nakon tri meseca i 0,89±0,22 mm mezijalno i 0,74±0,20mm distalno nakon šest meseci.Zaključak. Primenom piezo hirurgije, kombinovanom sa odgovarajućimosteotomijama i širenjem alveolarnih grebenova, omogućena je imedijatna,jednofazna implantacija u područjima u kojima je to pre pojave ove tehnikebilo nemoguće sprovesti.

Quantitative Sequencing for the Determination of Kdr-type Resistance Allele (V419L, L925I, I936F) Frequencies in Common Bed Bug (Hemiptera: Cimicidae) Populations Collected from Israel

2015 ◽  
Vol 52 (5) ◽  
pp. 1018-1027 ◽  
Author(s):  
Daniel J. Palenchar ◽  
Kyle J. Gellatly ◽  
Kyong Sup Yoon ◽  
Kosta Y. Mumcuoglu ◽  
Uri Shalom ◽  
...  
Keyword(s):  
Resistance Allele ◽  
Bed Bug
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