The Ah receptor: adaptive metabolism, ligand diversity, and the xenokine model

Author Posting. © American Chemical Society, 2020. This is an open access article published under an ACS AuthorChoice License. The definitive version was published in Chemical Research in Toxicology, 33(4), (2020): 860-879, doi:10.1021/acs.chemrestox.9b00476.The Ah receptor (AHR) has been studied for almost five decades. Yet, we still have many important questions about its role in normal physiology and development. Moreover, we still do not fully understand how this protein mediates the adverse effects of a variety of environmental pollutants, such as the polycyclic aromatic hydrocarbons (PAHs), the chlorinated dibenzo-p-dioxins (“dioxins”), and many polyhalogenated biphenyls. To provide a platform for future research, we provide the historical underpinnings of our current state of knowledge about AHR signal transduction, identify a few areas of needed research, and then develop concepts such as adaptive metabolism, ligand structural diversity, and the importance of proligands in receptor activation. We finish with a discussion of the cognate physiological role of the AHR, our perspective on why this receptor is so highly conserved, and how we might think about its cognate ligands in the future.This review is dedicated in memory of the career of Alan Poland, one of the truly great minds in pharmacology and toxicology. This work was supported by the National Institutes of Health Grants R35-ES028377, T32-ES007015, P30-CA014520, P42-ES007381, and U01-ES1026127, The UW SciMed GRS Program, and The Morgridge Foundation. The authors would like to thank Catherine Stanley of UW Media Solutions for her artwork

Late pleistocene carnivores (Carnivora: Mammalia) from a cave sedimentary deposit in northern Brazil

The Brazilian Quaternary terrestrial Carnivora are represented by the following families: Canidae, Felidae, Ursidae, Procyonidae Mephitidae and Mustelidae. Their recent evolutionary history in South America is associated with the uplift of the Panamanian Isthmus, and which enabled the Great American Biotic Interchange (GABI). Here we present new fossil records of Carnivora found in a cave in Aurora do Tocantins, Tocantins, northern Brazil. A stratigraphical controlled collection in the sedimentary deposit of the studied cave revealed a fossiliferous level where the following Carnivora taxa were present: Panthera onca, Leopardus sp., Galictis cuja, Procyon cancrivorus, Nasua nasua and Arctotherium wingei. Dating by Electron Spinning Resonance indicates that this assemblage was deposited during the Last Glacial Maximum (LGM), at least, 22.000 YBP. The weasel, G. cuja, is currently reported much further south than the record presented here. This may suggest that the environment around the cave was relatively drier during the LGM, with more open vegetation, and more moderate temperatures than the current Brazilian Cerrado.Facultad de Ciencias Naturales y Muse

Aktivität und Vorkommen geflügelter Blattläuse auf Freilandpaprika in Spanien

Horizontal mosaic-green-tile traps were placed in various pepper-growing areas of Spain: Aranjuez and Arganda del Rey (Madrid), Balboa (Badajoz), Cadreita (Pamplona), Mendavia and Sartaguda (Logroño), Montañana (Zaragoza), Pueblo Nuevo (Valencia) and Torrepacheco (Murcia). These mosaic-greentraps resembled much better the pepper canopy than the commonly used yellow water traps, as indicated by absorbance spectrophotometry. Sampling was extended throughout the pepper crop cycle during 1990, 1991 and 1992. Over that time, 14,363 aphids, belonging to 99 species/taxa were captured. Aphis was the principal genus captured: 57.5 % of the total (17 % belonging to the species Aphis fabae (Scopoli)). Other abundant species were: Myzus (Nectarosiphon) persicae (Sulzer) (7.46 %), Diuraphis noxia (Mordvilko) (5.23 %), Brachycaudus spp. (3.73 %), Sitobion avenae (F.) (2.51 %), Macrosiphum euphorbiae (Thomas) (2.46 %), Rhopalosiphum spp. (2.20 %) and Therioaphis spp. (1.99 %). The species included in the genus Aphis were the most abundant in all the regions sampled, although M. (N.) persicae was also predominant in the Zaragoza and Pamplona region, and D. noxia was frequently found in the Madrid region. A first aphid peak was observed soon after transplanting (May–June) in most of the regions and years sampled.Horizontale mosaikgrüne Farbfallen wurden in verschiedenen Paprika-Anbaugebieten in Spanien aufgestellt: Aranjuez und Arganda del Rey (Madrid), Balbao (Badajoz), Cadreita (Pamplona), Mendavia und Sartaguda (Logroño), Montañana (Zaragoza), Pueblo Nuevo (Valencia) und Torrepacheco (Murcia). Diese mosaikgrünen Fallen ähnelten sehr viel besser den Farben des Paprikabestandes als die üblicherweise eingesetzten gelben Wasserfallen wie durch Absorptionsspektrometrie festgestellt wurde. Die Probennahmen erfolgten während der ganzen Wachstumsphasen des Paprikas in den Jahren 1990, 1991 und 1992. In diesen Zeiträumen konnten 14363 Blattläuse gefangen werden, die 99 Arten/Taxa angehörten. Die Gattung Aphis wurde mit 57,5 % am häufigsten gefangen, 17 % gehörten zur Art Aphis fabae (Scopoli). Andere häufig vorkommende Arten waren: Myzus (Nectarosiphon) persicae (Sulzer) (7,46 %), Diuraphis noxia (Mordvilko) (5,23 %), Brachycaudus spp. (3,73 %), Sitobion avenae (F.) (2,51 %), Macrosiphum euphorbiae (Thomas) (2,46 %), Rhopalosiphum spp. (2,20 %) und Therioaphis spp. (1,99 %). Die zur Gattung Aphis gehörenden Arten waren in allen beprobten Regionen am häufigsten, obgleich M. (N.) persicae in den Regionen Zaragoza und Pamplona auch sehr häufig vorkam. D. noxia trat häufig in der Madrider Region auf. Ein erster Höhehoug punkt des Blattlausaufretens wurde in den meisten Regionen und Jahren schon bald nach dem Auspflanzen (Mai–Juni) beobachtet.This work was supported by the Interministerial Commision for Science and Technology of Spain (Comisión Interministerial de Ciencia y Tecnología, grant AGR91-0448)..Peer reviewe

Late pleistocene carnivores (Carnivora: Mammalia) from a cave sedimentary deposit in northern Brazil

The Brazilian Quaternary terrestrial Carnivora are represented by the following families: Canidae, Felidae, Ursidae, Procyonidae Mephitidae and Mustelidae. Their recent evolutionary history in South America is associated with the uplift of the Panamanian Isthmus, and which enabled the Great American Biotic Interchange (GABI). Here we present new fossil records of Carnivora found in a cave in Aurora do Tocantins, Tocantins, northern Brazil. A stratigraphical controlled collection in the sedimentary deposit of the studied cave revealed a fossiliferous level where the following Carnivora taxa were present: Panthera onca, Leopardus sp., Galictis cuja, Procyon cancrivorus, Nasua nasua and Arctotherium wingei. Dating by Electron Spinning Resonance indicates that this assemblage was deposited during the Last Glacial Maximum (LGM), at least, 22.000 YBP. The weasel, G. cuja, is currently reported much further south than the record presented here. This may suggest that the environment around the cave was relatively drier during the LGM, with more open vegetation, and more moderate temperatures than the current Brazilian Cerrado.Facultad de Ciencias Naturales y Muse

Ecomorphology and feeding behavior of the Pleistocene South American equids (Mammalia, Perissodactyla, Equidae)

The fossil record of the South American Pleistocene presents two Equidae taxa: Hippidion Owen and Equus (Amerhippus) Hoffstetter. These equids were possibly sympatric and, although being considered closely related, present distinct cranial morphologies. This study aimed to verify possible variations on the masticatory patterns and dental wear between both genera, as well as to compare their rostral morphology and functional differences related to feeding habits. We performed quantitative analyses of macrowear and occlusion surface area of teeth from Toca dos Ossos (Bahia, Brazil). The morphofunctional analysis was conducted using photographs of specimens housed at the Museo de La Plata (La Plata, Argentina) and Museu de Ciências Naturais PUC Minas (Minas Gerais, Brazil), and based on the anatomy of the extant horse Equus caballus Linnaeus, due to its resemblance to E. (Amerhippus). Results showed that E. (Amerhippus) exhibits a more significant macrowear on the antero-posterior region of the teeth, while Hippidion has a more uniform wear. Analyses of occlusion surface area confirm the difference on the structure of dental enamel between genera, where Hippidion presents more complex folds. The morphofuctional analysis indicates that the rostral portion and the premaxillary shape of E. (Amerhippus) are similar to E. caballus. However, based on anatomical studies of the premaxillary region of other extinct ungulates, Hippidion exhibits morphological structures compatible with the presence of a vestibular proboscis and premaxillary region usually found on browsing ungulates. These results indicated that E. (Amerhippus) had the capacity to feed on more abrasive food items than Hippidion. Nevertheless, the morphofunctional dissimilarities on their skull suggest marked variations on their ecomorphological strategies. Therefore, these two different approaches corroborate our point of view that Hippidion and E. (Amerhippus), despite their possible sympatry, presented consistent mechanisms related to the reduction of niche overlap concerning the partition of food resources.Sesiones libresFacultad de Ciencias Naturales y Muse

Vip3C, a novel class of vegetative insectidal proteins from Bacillus thuringiensis

Three vip3 genes were identified in two Bacillus thuringiensis Spanish collections. Sequence analysis revealed a novel Vip3 protein class (Vip3C). Preliminary bioassays of larvae from 10 different lepidopteran species indicated that Vip3Ca3 caused more than 70% mortality in four species after 10 days at 4 μg/cm2