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N Anthony

Publications and source records attributed to N Anthony.

At least 19 recordsLinked to original sources
PubMed2003

Incidence of insecticide resistance alleles in sexually-reproducing populations of the peach-potato aphid Myzus persicae (Hemiptera: Aphididae) from southern France.

Intensive chemical treatments have led to the development of a number of insecticide resistance mechanisms in the peach-potato aphid Myzus persicae (Sulzer). Some of these mechanisms are known to be associated with negative pleiotropic effects (resistance costs). Molecular and biochemical methods were used to determine the genotypes or phenotypes associated with four insecticide resistance mechanisms in single aphids from sexually-reproducing populations in southern France. The mechanisms considered were E4 and FE4 carboxylesterase overproduction, modified acetycholinesterase, and kdr and rdl resistance-associated mutations. A new method for determining individual kdr genotypes is presented. Almost all resistant individuals overproduced FE4 carboxylesterase, whereas modified acetylcholinesterase was rare. Both the kdr and rdl resistance mutations were present at high frequencies in French sexually-reproducing populations. The frequencies of insecticide resistance genes were compared before and after sexual reproduction in one peach orchard at Avignon to evaluate the potential impact of selection on the persistence of resistance alleles in the over-wintering phase. The frequencies of the kdr and rdl mutations varied significantly between autumn and spring sampling periods. The frequency of the kdr mutation increased, probably due to pyrethroid treatments at the end of the winter. Conversely, the frequency of the rdl mutation decreased significantly during winter, probably because of a fitness cost associated with this mutation.

Acetylcholinesterase↗
PubMed2000

HIV-1 integrase inhibitors that compete with the target DNA substrate define a unique strand transfer conformation for integrase.

Diketo acids such as L-731,988 are potent inhibitors of HIV-1 integrase that inhibit integration and viral replication in cells. These compounds exhibit the unique ability to inhibit the strand transfer activity of integrase in the absence of an effect on 3' end processing. To understand the reasons for this distinct inhibitory profile, we developed a scintillation proximity assay that permits analysis of radiolabeled inhibitor binding and integrase function. High-affinity binding of L-731,988 is shown to require the assembly of a specific complex on the HIV-1 long terminal repeat. The interaction of L-731,988 with the complex and the efficacy of L-731, 988 in strand transfer can be abrogated by the interaction with target substrates, suggesting competition between the inhibitor and the target DNA. The L-731,988 binding site and that of the target substrate are thus distinct from that of the donor substrate and are defined by a conformation of integrase that is only adopted after assembly with the viral end. These results elucidate the basis for diketo acid inhibition of strand transfer and have implications for integrase-directed HIV-1 drug discovery efforts.

Acetoacetates↗
PubMed2000

Cyclodiene insecticide resistance: from molecular to population genetics.

This review follows progress in the analysis of cyclodiene insecticide resistance from the initial isolation of the mutant, through cloning of the resistance gene, to an examination of the distribution of resistance alleles in natural populations. Emphasis is given to the use of a resistant Drosophila mutant as an entry point to cloning the associated gamma-aminobutyric acid (GABA) receptor subunit gene, Resistance to dieldrin. Resistance is associated with replacements of a single amino acid (alanine302) in the chloride ion channel pore of the protein. Replacements of alanine302 not only directly affect the drug binding site but also allosterically destabilize the drug preferred conformation of the receptor. Resistance is thus conferred by a unique dual mechanism associated with alanine302, which is the only residue replaced in a wide range of different resistant insects. The underlying mutations appear either to have arisen once, or multiply, depending on the population biology of the pest insect. Although resistance frequencies decline in the absence of selection, resistance alleles can persist at relatively high frequency and may cause problems for compounds to which cross-resistance is observed, such as the novel fipronils.

Animals↗
PubMed1998

Why are there so few resistance-associated mutations in insecticide target genes?

The genes encoding the three major targets of conventional insecticides are: Rdl, which encodes a gamma-aminobutyric acid receptor subunit (RDL); para, which encodes a voltage-gated sodium channel (PARA); and Ace, which encodes insect acetylcholinesterase (AChE). Interestingly, despite the complexity of the encoded receptors or enzymes, very few amino acid residues are replaced in different resistant insects: one within RDL, two within PARA and three or more within AChE. Here we examine the possible reasons underlying this extreme conservation by looking at the aspects of receptor and/or enzyme function that may constrain replacements to such a limited number of residues.

Acetylcholinesterase↗
PubMed1998

Duplication of the Rdl GABA receptor subunit gene in an insecticide-resistant aphid, Myzus persicae.

Resistance to cyclodiene insecticides is associated with replacements of a single amino acid (alanine 302) in a gamma-aminobutyric acid (GABA) receptor subunit encoded by the single-copy gene Resistance to dieldrin (Rdl). Alanine 302 is predicted to reside within the second membrane-spanning region of the Rdl receptor, a region that is thought to line the integral chloride ion channel pore. In all cyclodiene-resistant insects studied to date, this same alanine residue is replaced either by a serine, or, in some resistant strains of Drosophila simulans, a glycine residue. Therefore, individuals can carry only two different Rdl alleles. In contrast, here we report the presence of up to four different Rdl-like alleles in individual clones of the green peach aphid, Myzus persicae. In addition to the wild-type copy of Rdl gene (encoding A302 or allele A), M. persicae carries three other alleles with the following amino acid replacements: A302-->Glycine (allele G), A302-->SerineTCG (allele S) and A302-->SerineAGT (allele S'). Evidence from direct nucleotide sequencing and Single Stranded Conformational Polymorphism (SSCP) analysis shows that at least three of these different Rdl alleles (i.e. A, G and S) are commonly present in individual aphids or aphid clones. Southern analysis using allele-specific probes and analysis of sequences downstream of the exon containing the resistance-associated mutation confirm the presence of two independent Rdl-like loci in M. persicae. One locus carries the susceptible alanine (A) and/or resistant glycine (G) allele while the other carries the two serine alleles (S or S'). Whereas resistance levels are correlated with the glycine replacement, the S allele was present in all aphid clones, regardless of their resistance status. These results suggest that target site insensitivity is associated with replacements at the first (A/G) but not the second (S/S') locus. Phylogenetic analysis of nucleotide sequences indicates that both putative aphid Rdl loci are monophyletic with respect to other insect Rdl genes and may have arisen through a recent gene duplication event. The implications of this duplication with respect to insecticide resistance and insect GABA receptor subunit diversity are discussed.

Alanine↗
PubMed1998

Analysis of a mosquito acetylcholinesterase gene promoter.

Insect acetylcholinesterase is the target site for organophosphorus and carbamate insecticides and point mutations in the Ace gene are associated with resistance in Drosophila melanogaster and Musca domestica. However, little is known of the genetic regulation of insect Ace genes. Here we report the isolation of four different cDNAs from an Aedes Ace locus and identification of the gene promoter. Northern analysis reveals two large (>10 kb) transcripts and one smaller transcript of 4 kb. The region containing the initiation of transcription was localized by sequencing the two 5' most cDNAs and by 5' RACE. The transcription start point was subsequently identified by primer extension and is flanked by a perfect arthropod initiator consensus sequence. The promoter lacks a TATA box but contains several matches to other consensus sequences for eukaryotic transcription factors. In common with the Drosophila Ace gene, there are also multiple potential initiators of translation (ATGs) upstream of the main open reading frame. The structure of the 5' leader and promoter is compared to that found in other insect and vertebrate Ace genes and the possibility that this locus is homologous to one of two Ace loci described in another mosquito, Culex pipiens, is discussed.

Acetylcholinesterase↗
PubMed1995

Cloning, sequencing and functional expression of an acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti.

A degenerate PCR strategy was used to isolate a fragment of the acetylcholinesterase gene (Ace) homolog from Aedes aegypti and screen for a cDNA clone containing the complete open reading frame of the gene. The predicted amino acid sequence of the Aedes gene shares 64% identity with Ace from Drosophila and 87% identity with the acetylcholinesterase gene from another mosquito species Anopheles stephensi. High levels of expression of the Aedes gene were achieved by infection of Sf21 cells with a recombinant baculovirus containing the Aedes Ace cDNA. The catalytic properties and sensitivity of the recombinant enzyme to insecticide inhibition are described and discussed in relation to the role of insensitive AChE in conferring resistance to organophosphorus and carbamate insecticides.

Acetylcholinesterase↗
PubMed1993

Simultaneous ligation of CD5 and CD28 on resting T lymphocytes induces T cell activation in the absence of T cell receptor/CD3 occupancy.

The T cell surface molecules CD5 and CD28 have been shown to be receptors for accessory signals in T cell activation. We here demonstrate that in the absence of any other activating stimulus, simultaneous ligation of CD5 and CD28 by mAb induces polyclonal T cell activation. Immobilization of the anti-CD28 and anti-CD5 mAb was an essential requirement for T cell stimulation. This was done either through coating of the culture plates with goat anti-mouse Ig, or by coculture with mitomycin C-treated Fc gamma R-bearing P815 mouse mastocytoma cells. Most importantly, T cells could also be stimulated with B7, the natural ligand of CD28, and anti-CD5 presented on irradiated 3T6 mouse fibroblasts co-transfected with human Fc gamma RII and with B7. Neither immobilized mAb 9.3 (anti-CD28) nor any of four different anti-CD5 mAb were mitogenic as a sole stimulus. Immobilized mAb identifying CD4, CD7, or LFA-1 were not co-mitogenic with either mAb 9.3 or one of the anti-CD5 mAb. The T cell proliferation induced by cross-linking of CD5 and CD28 is IL-2-dependent, as was demonstrated by the cell-surface expression of the p55 chain of the IL-2R, the production of IL-2, and inhibition of the proliferative response by the anti-IL-2R mAb anti-Tac. CD5/CD28 ligation induced production of TNF-alpha, but not of IL-4, and did not induce modulation of the TCR/CD3 complex. Expression of IL-2R (p55) and of CD69 preferentially occurred on CD29-low naive cells, and indicated that about 50% of the cultured cells were activated. Cell proliferation was not increased by adding monocytes to the cultures and it was inhibited by PKC inhibitors (H7 and staurosporine) and by cyclosporine A. In conclusion, our data provide evidence for a pathway of Ag-independent T cell activation via CD5 and CD28, which preferentially stimulates native T cells.

Animals↗
PubMed1993

Compromised antioxidant status associated with ascites in broilers.

Tissue infiltration by white blood cells in poultry with ascites has been reported, which could alter endogenous antioxidant status from oxidant stress. Therefore, the objective of this study was to determine the effect of ascites on ascorbic acid, tocopherol, and glutathione (GSH), which are major intracellular antioxidants. Broiler chicks (1 day) were placed in environmental chambers maintained with normal ventilation (Control) or under low ventilation, which produced a cumulative mortality of 31.3% due to ascites. At 3, 5, and 7 wk, lung and liver tissues were obtained from control birds (n = 5) and from birds in the low ventilation chamber with (ASC, n = 5) or without (NASC, n = 5) overt symptoms of ascites. There were no differences in tissue ascorbate, tocopherol, and GSH between the control and NASC groups with the exception of hepatic tocopherol at 7 wk, which was higher (P < .05) in NASC birds than in ASC and control birds. In general, lung and liver concentrations of all three antioxidants were lower (P < .05) in ASC birds than in NASC and control groups. Uric acid, a product of purine metabolism, was lower (P < .05) in liver and lung in ASC birds at 3 wk compared with control birds. However, uric acid concentrations in ASC birds were higher (P < .05) in the lung and serum at 5 wk, and in the liver at 7 wk compared with NASC and control birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

A longitudinal analysis of the effect of experience on the therapeutic approach: revisited.

The published results of readministering the Therapist Orientation Questionnaire to a group of "low experience" therapists (N = 60) 4 years after an initial administration were recalculated due to scoring errors. Ss had been classified into Freudian, Sullivanian, and Rogerian schools. Differences present among schools on several TOQ factors were present initially and were mostly still there at the readministration. Although relative to each other the groups were stable, many scores shifted, essentially, away from a Freudian philosophy.

Attitude of Health Personnel↗
PubMed1979

The state mental hospital: a local health department's role.

The publicizing of the abysmal conditions in state mental institutions and the problems precipitated by their deinstitutionalization programs, have challenged local health authorities to develop effective roles in ameliorating these difficulties. Long-view State Hospital is a state mental hospital in Cincinnati, Ohio. The Cincinnati Health Department acted as a change agent to deal with the hospital's many chronic problems and the new difficulties precipitated by moving patients into the community for care. The city conducted its own evaluation of the hospital and its deinstitutionalization program and strongly advocated needed improvements. Problems were encountered in implementing this advocacy role, particularly in relation to the local health department's authority regarding this state-funded and operated institution. However, the many city recommendations that were implemented, the increased funding given the hospital and the community mental health centers, the continuing communication between city and state officials, as well as a follow-up evaluation indicated that the Cincinnati Health Department had played a positive role in the change process. (Am. J. Public Health 69:64-67, 1979.)

Government Agencies↗
PubMed1977

Immunization: public health programming through law enforcement.

The pre-inoculation program review of the school immunization records in fall, 1974 found that only 60 per cent of the 63,000 children in the Cincinnati primary school system were adequately immunized. Following a program based upon their legal authority to require immunizations, the Board of Health in collaboration with the Board of Education was able to obtain in a two-year effort a 91 per cent immunization level.

Child↗
PubMed1976

Malingering as role taking.

This study investigated the relationship among psychopathology, intelligence and the simulation of psychopathological roles. The 132 Ss were 48 inpatients, 48 outpatients, and 36 nonprofessional employees. Each S simulated the MMPI profile of an anxiety neurotic, psychopathic deviate, or paranoid schizophrenic. Their simulation target was dissimilar to their diagnosis and/or Personality Screening Inventory profile. The findings were: (1) the hypothesized negative relationship between psychopathology and psychopathological role-taking was not supported broadly, but was supported more with males, blacks, neurotics, and simulators of the psychopathic deviate personality; and (2) the hypothesized positive relationship between intelligence and the simulation of psychopathological roles was supported in a small but definite relationship, with greater support among the Caucasians, males, neurotics, simulators of the 2-7 and 6-8 profile patterns, and when the simulation measure emphasized scatter and elevation similarities.

Adult↗