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1.
Pestic Biochem Physiol ; 166: 104562, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32448417

RESUMO

The buff-tailed bumblebee, Bombus terrestris audax is an important pollinator within both landscape ecosystems and agricultural crops. During their lifetime bumblebees are regularly challenged by various environmental stressors including insecticides. Historically the honey bee (Apis mellifera spp.) has been used as an 'indicator' species for 'standard' ecotoxicological testing, but it has been suggested that it is not always a good proxy for other eusocial or solitary bees. To investigate this, the susceptibility of B. terrestris to selected pesticides within the neonicotinoid, pyrethroid and organophosphate classes was examined using acute insecticide bioassays. Acute oral and topical LD50 values for B. terrestris against these insecticides were broadly consistent with published results for A. mellifera. For the neonicotinoids, imidacloprid was highly toxic, but thiacloprid and acetamiprid were practically non-toxic. For pyrethroids, deltamethrin was highly toxic, but tau-fluvalinate only slightly toxic. For the organophosphates, chlorpyrifos was highly toxic, but coumaphos practically non-toxic. Bioassays using insecticides with common synergists enhanced the sensitivity of B. terrestris to several insecticides, suggesting detoxification enzymes may provide a level of protection against these compounds. The sensitivity of B. terrestris to compounds within three different insecticide classes is similar to that reported for honey bees, with marked variation in sensitivity to different insecticides within the same insecticide class observed in both species. This finding highlights the need to consider each compound within an insecticide class in isolation rather than extrapolating between different insecticides in the same class or sharing the same mode of action.


Assuntos
Inseticidas , Animais , Abelhas , Combinação de Medicamentos , Ecossistema , Glicerol , Salicilatos
2.
Pestic Biochem Physiol ; 169: 104674, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32828379

RESUMO

There is an on-going need to develop new insecticides that are not compromised by resistance and that have improved environmental profiles. However, the cost of developing novel compounds has increased significantly over the last two decades. This is in part due to increased regulatory requirements, including the need to screen both pest and pollinator insect species to ensure that pre-existing resistance will not hamper the efficacy of a new insecticide via cross-resistance, or adversely affect non-target insect species. To add to this problem the collection and maintenance of toxicologically relevant pest and pollinator species and strains is costly and often difficult. Here we present Fly-Tox, a panel of publicly available transgenic Drosophila melanogaster lines each containing one or more pest or pollinator P450 genes that have been previously shown to metabolise insecticides. We describe the range of ways these tools can be used, including in predictive screens to avoid pre-existing cross-resistance, to identify potential resistance-breaking inhibitors, in the initial assessment of potential insecticide toxicity to bee pollinators, and identifying harmful pesticide-pesticide interactions.


Assuntos
Resistência a Inseticidas/efeitos dos fármacos , Inseticidas/farmacologia , Animais , Animais Geneticamente Modificados , Abelhas , Sistema Enzimático do Citocromo P-450 , Drosophila melanogaster/efeitos dos fármacos
3.
Elife ; 112022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36164830

RESUMO

Are animals' preferences determined by absolute memories for options (e.g. reward sizes) or by their remembered ranking (better/worse)? The only studies examining this question suggest humans and starlings utilise memories for both absolute and relative information. We show that bumblebees' learned preferences are based only on memories of ordinal comparisons. A series of experiments showed that after learning to discriminate pairs of different flowers by sucrose concentration, bumblebees preferred flowers (in novel pairings) with (1) higher ranking over equal absolute reward, (2) higher ranking over higher absolute reward, and (3) identical qualitative ranking but different quantitative ranking equally. Bumblebees used absolute information in order to rank different flowers. However, additional experiments revealed that, even when ranking information was absent (i.e. bees learned one flower at a time), memories for absolute information were lost or could no longer be retrieved after at most 1 hr. Our results illuminate a divergent mechanism for bees (compared to starlings and humans) of learned preferences that may have arisen from different adaptations to their natural environment.


Assuntos
Comportamento Alimentar , Estorninhos , Animais , Abelhas , Flores , Humanos , Recompensa , Sacarose
4.
G3 (Bethesda) ; 8(10): 3357-3366, 2018 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-30139764

RESUMO

The haplodiploid system of sex determination of Hymenoptera acts as an exaptation for species to evolve novel forms of asexual reproduction including thelytoky (clonal offspring of the mother). During normal reproduction in Hymenoptera, three of the four products of meiosis that are present in newly-laid eggs are lost as polar bodies, while the remaining pronucleus either develops as a haploid male or fuses with a sperm nucleus to produce a diploid zygote. In contrast, in thelytokous reproduction, which is uncommon but taxonomically widespread, two of the four products of meiosis fuse, as if one acted as a sperm. Queenless workers of Apis mellifera capensis, a subspecies of honey bee from South Africa, routinely reproduce thelytokously. Unmated A. m. capensis queens can also be induced to lay thelytokously by narcosis with carbon dioxide, but mated queens are never thelytokous. We artificially inseminated A. m. capensis queens using CO2 narcosis. Up to 1/3 of offspring workers carried two maternal alleles and an allele of one father whereas no three-allele progeny were seen in control queens of the arrhenotokous (unfertilized eggs result in males) subspecies A. m. scutellata Flow cytometry of three-allele individuals revealed that they were triploid and arose from the fertilization of a thelytokous fusion nucleus. We then reared six queens from a narcotized A. m. capensis queen and determined the ploidy of the offspring queens based on microsatellites. One of the five daughters was triploid. Following artificial insemination, this queen produced unfertilized thelytokous diploid eggs at high frequency, and unfertilized triploid eggs at much lower frequency. If fertilized, thelytokous diploid eggs were non-viable, even though triploidy in itself does not impede normal development. In contrast, when the rarer triploid eggs were fertilized, a proportion developed into viable tetraploids. Our study highlights the extraordinary developmental flexibility of haplo-diploid systems.


Assuntos
Abelhas/genética , Abelhas/metabolismo , Dióxido de Carbono/metabolismo , Triploidia , Alelos , Animais , Feminino , Citometria de Fluxo , Masculino , Mosaicismo , Partenogênese , Fenótipo , Ploidias
5.
J Med Chem ; 49(21): 6209-21, 2006 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-17034127

RESUMO

From a set of weakly potent lead compounds, using in silico screening and small library synthesis, a series of 2-alkyl-3-aryl-3-alkoxyisoindolinones has been identified as inhibitors of the MDM2-p53 interaction. Two of the most potent compounds, 2-benzyl-3-(4-chlorophenyl)-3-(3-hydroxypropoxy)-2,3-dihydroisoindol-1-one (76; IC(50) = 15.9 +/- 0.8 microM) and 3-(4-chlorophenyl)-3-(4-hydroxy-3,5-dimethoxybenzyloxy)-2-propyl-2,3-dihydroisoindol-1-one (79; IC(50) = 5.3 +/- 0.9 microM), induced p53-dependent gene transcription, in a dose-dependent manner, in the MDM2 amplified, SJSA human sarcoma cell line.


Assuntos
Antineoplásicos/síntese química , Indóis/síntese química , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Técnicas de Química Combinatória , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/química , Indóis/farmacologia , Modelos Moleculares , Ligação Proteica , Estereoisomerismo , Relação Estrutura-Atividade , Transcrição Gênica , Proteína Supressora de Tumor p53/genética
6.
Bioorg Med Chem Lett ; 15(5): 1515-20, 2005 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15713419

RESUMO

A series of 2-N-alkyl-3-aryl-3-alkoxyisoindolinones has been synthesised and evaluated as inhibitors of the MDM2-p53 interaction. The most potent compound, 3-(4-chlorophenyl)-3-(4-hydroxy-3,5-dimethoxybenzyloxy)-2-propyl-2,3-dihydroisoindol-1-one (NU8231), exhibited an IC50 of 5.3 +/- 0.9 microM in an ELISA assay, and induced p53-dependent gene transcription in a dose-dependent manner, in the SJSA human sarcoma cell line.


Assuntos
Indóis/química , Indóis/farmacologia , Proteínas Nucleares/efeitos dos fármacos , Proteínas Proto-Oncogênicas/efeitos dos fármacos , Proteína Supressora de Tumor p53/efeitos dos fármacos , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Humanos , Indóis/síntese química , Modelos Moleculares , Estrutura Molecular , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-mdm2 , Relação Estrutura-Atividade , Transcrição Gênica/efeitos dos fármacos , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
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