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An excavation of an Early Iron Age village near Aalborg in Denmark uncovered the jaws and skull fragments from a small mammal that were morphologically identified to the genus Crocidura (white-toothed shrews). Three Crocidura species are known from prehistoric continental Europe but none of them are distributed in Scandinavia, which is why this surprising finding warranted further analyses. The bone was radiocarbon-dated to 2840-2750 calibrated years before present (cal. BP), corresponding to the Late Bronze Age and hence earlier than the Iron Age archeological context in which it was found. Using highly optimized ancient DNA protocols, we extracted DNA from one tooth and shotgun-sequenced the sample to reconstruct a near-complete mitochondrial reference genome (17,317 bp, 32.6× coverage). Phylogenetic analyses determined this specimen as a bicolored shrew (Crocidura leucodon) but with a phylogenetic position basal to the clade of known sequences from this species. The confirmation of Crocidura presence in Denmark by the Late Bronze Age sheds new light on the prehistoric natural history of Scandinavia. We discuss the implications of this finding from both zoo-archeological and ecological perspectives. Furthermore, the mitochondrial genome reconstructed in this study offers a valuable resource for future research exploring the genetic makeup and evolutionary history of Eurasian shrew populations.
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Environmental DNA (eDNA) analyses of species present in marine environments is the most effective biological diversity measurement tool currently available. eDNA sampling methods are an intrinsically important part of the eDNA biodiversity analysis process. Identification and development of eDNA sampling methods that are as rapid, affordable, versatile and practical as possible will improve rates of detection of marine species. Optimal outcomes of eDNA biodiversity surveys come from studies employing high levels of sampling replication, so any methods that make sampling faster and cheaper will improve scientific outcomes. eDNA sampling methods that can be applied more widely will also enable sampling from a greater range of marine surface micro-habitats, resulting in detection of a wider range of organisms. In this study, we compared diversity detection by several methods for sampling eDNA from submerged marine surfaces: polyurethane foam, nylon swabs, microfibre paint rollers, and sediment scoops. All of the methods produced a diverse range of species identifications, with >250 multicellular species represented by eDNA at the study site. We found that widely-available small paint rollers were an effective, readily available and affordable method for sampling eDNA from underwater marine surfaces. This approach enables the sampling of marine eDNA using extended poles, or potentially by remotely operated vehicles, where surface sampling by hand is impractical.
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Biodiversidad , ADN Ambiental , Pintura , Pintura/análisis , ADN Ambiental/análisis , Organismos Acuáticos/genética , Manejo de Especímenes/métodos , Monitoreo del Ambiente/métodos , PoliuretanosRESUMEN
Since 1968, the Australian Dung Beetle Project has carried out field releases of 43 deliberately introduced dung beetle species for the biological control of livestock dung and dung-breeding pests. Of these, 23 species are known to have become established. For most of these species, sufficient time has elapsed for population expansion to fill the extent of their potential geographic range through both natural and human-assisted dispersal. Consequently, over the last 20 years, extensive efforts have been made to quantify the current distribution of these introduced dung beetles, as well as the seasonal and spatial variation in their activity levels. Much of these data and their associated metadata have remained unpublished, and they have not previously been synthesized into a cohesive dataset. Here, we collate and report data from the three largest dung beetle monitoring projects from 2001 to 2022. Together, these projects encompass data collected from across Australia, and include records for all 23 species of established dung beetles introduced for biocontrol purposes. In total, these data include 22,718 presence records and 213,538 absence records collected during 10,272 sampling events at 546 locations. Most presence records (97%) include abundance data. In total, 1,752,807 dung beetles were identified as part of these data. The distributional occurrence and abundance data can be used to explore questions such as factors influencing dung beetle species distributions, dung beetle biocontrol, and insect-mediated ecosystem services. These data are provided under a CC-BY-NC 4.0 license and users are encouraged to cite this data paper when using the data.
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Escarabajos , Especies Introducidas , Escarabajos/fisiología , Animales , Australia , Factores de Tiempo , Distribución Animal , Dinámica Poblacional , Densidad de PoblaciónRESUMEN
Crabs can be transported beyond their native range via anthropogenic-mediated means such as aquarium trade, live seafood trade and shipping. Once introduced into new locations, they can establish persisting populations and become invasive, often leading to negative impacts on the recipient environment and native species. Molecular techniques are increasingly being used as complementary tools in biosecurity surveillance and monitoring plans for invasive species. Molecular tools can be particularly useful for early detection, rapid identification and discrimination of closely related species, including when diagnostic morphological characters are absent or challenging, such as early life stages, or when only part of the animal is available. In this study, we developed a species-specific qPCR assay, which targets the cytochrome c oxidase subunit 1 (CO1) region of the Asian paddle crab Charybdis japonica. In Australia, as well as many parts of the world, this species is considered invasive and routine biosecurity surveillance is conducted to reduce the risk of establishment. Through rigorous testing of tissue from target and non-target species we demonstrate that this assay is sensitive enough to detect as little as two copies per reaction and does not cross amplify with other closely related species. Field samples and environmental samples spiked with C. japonica DNA in high and low concentrations indicate that this assay is also a promising tool for detecting trace amounts of C. japonica eDNA in complex substrates, making it a useful complementary tool in marine biosecurity assessments.
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Crustáceos , ADN , Animales , Reacción en Cadena en Tiempo Real de la Polimerasa , ADN/análisis , Crustáceos/genética , Australia , Especies IntroducidasRESUMEN
Topographically ordered projections are established by molecular guidance cues and refined by neuronal activity. Retinal input to a primary visual center, the superior colliculus (SC), is bilateral with a dense contralateral projection and a sparse ipsilateral one. Both projections are topographically organized, but in opposing anterior-posterior orientations. This arrangement provides functionally coherent input to each colliculus from the binocular visual field, supporting visual function. When guidance cues involved in contralateral topography (ephrin-As) are absent, crossed retinal ganglion cell (RGC) axons form inappropriate terminations within the SC. However, the organization of the ipsilateral projection relative to the abnormal contralateral input remains unknown, as does the functional capacity of both projections. We show here that in ephrin-A(-/-) mice, the SC contains an expanded, diffuse ipsilateral projection. Electrophysiological recording demonstrated that topography of visually evoked responses recorded from the contralateral superior colliculus of ephrin-A(-/-) mice displayed similar functional disorder in all genotypes, contrasting with their different degrees of anatomical disorder. In contrast, ipsilateral responses were retinotopic in ephrin-A2(-/-) but disorganized in ephrin-A2/A5(-/-) mice. The lack of integration of binocular input resulted in specific visual deficits, which could be reversed by occlusion of one eye. The discrepancy between anatomical and functional topography in both the ipsilateral and contralateral projections implies suppression of inappropriately located terminals. Moreover, the misalignment of ipsilateral and contralateral visual information in ephrin-A2/A5(-/-) mice suggests a role for ephrin-As in integrating convergent visual inputs.
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Efrina-A2/deficiencia , Efrina-A2/genética , Efrina-A5/deficiencia , Efrina-A5/genética , Lateralidad Funcional/genética , Retina/fisiología , Colículos Superiores/fisiología , Vías Visuales/fisiología , Animales , Mapeo Encefálico/métodos , Efrina-A2/biosíntesis , Efrina-A5/biosíntesis , Lateralidad Funcional/fisiología , Ratones , Ratones Noqueados , Terminaciones Nerviosas/patología , Terminaciones Nerviosas/fisiología , Estimulación Luminosa/métodos , Retina/patología , Células Ganglionares de la Retina/patología , Células Ganglionares de la Retina/fisiología , Colículos Superiores/patología , Vías Visuales/patologíaRESUMEN
Shark depredation is an issue of concern in some Western Australian recreational and commercial fisheries where it can have economic, social and ecological consequences. Knowledge of the shark species involved is fundamental to developing effective management strategies to mitigate the impacts of depredation. Identification of the species responsible is difficult as direct observation of depredation events is uncommon and evaluating bite marks on fish has a high degree of uncertainty. The use of trace DNA techniques has provided an alternative method for species identification. We demonstrate proof of concept for a targeted DNA barcoding approach to identify shark species using trace DNA found at bite marks on recovered remains of hooked fish. Following laboratory validation, forensic analysis of swabs collected from samples of bitten demersal fish, led to the definitive identification of shark species involved in 100% of the incidences of depredation (n = 16).
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Conservación de los Recursos Naturales/métodos , Código de Barras del ADN Taxonómico/métodos , ADN/análisis , Explotaciones Pesqueras , Tiburones/genética , Animales , Secuencia de Bases , Mordeduras y Picaduras/epidemiología , Mordeduras y Picaduras/fisiopatología , Citocromos b/genética , ADN/genética , Complejo IV de Transporte de Electrones/genética , Proteínas de Peces/genética , Incidencia , Homología de Secuencia de Ácido Nucleico , Tiburones/clasificación , Tiburones/fisiología , Especificidad de la Especie , Australia Occidental/epidemiologíaRESUMEN
In the developing visual system, growing retinal ganglion cell (RGC) axons are exposed to multiple guidance and growth factors. Furthermore, the relative levels of these factors are differentially regulated as topography is roughly established and then refined. We have shown that during the establishment of rough topography (P3), growth cones of pure and explanted RGCs treated with combinations of BDNF and ephrin-A5-Fc responded differently than RGCs treated with BDNF or ephrin-A5-Fc alone (p=0.0083). The response to the combined treatment mimicked that of RGCs cultured with ephrin-A5-Fc alone once topography refines. The guidance cue receptors EphA and TrkB were shown to co-localise in RGCs in vitro. Furthermore, EphA and TrkB receptors interacted directly in in vitro binding assays. Our results suggest that the conversion of growth cone responses from collapse to stabilisation as topography refines, occurs as a result of interactions between EphA and TrkB receptors.
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Factor Neurotrófico Derivado del Encéfalo/fisiología , Efrina-A5/fisiología , Neuritas/fisiología , Receptor trkB/metabolismo , Receptores de la Familia Eph/metabolismo , Vías Visuales/crecimiento & desarrollo , Animales , Factor Neurotrófico Derivado del Encéfalo/farmacología , Efrina-A5/farmacología , Conos de Crecimiento/efectos de los fármacos , Conos de Crecimiento/metabolismo , Conos de Crecimiento/fisiología , Ratones , Ratones Endogámicos C57BL , Neuritas/efectos de los fármacos , Neuritas/metabolismo , Ratas , Ratas Endogámicas , Células Ganglionares de la Retina/efectos de los fármacos , Células Ganglionares de la Retina/metabolismo , Células Ganglionares de la Retina/fisiología , Vías Visuales/efectos de los fármacos , Vías Visuales/metabolismoRESUMEN
The neuregulins (NRGs) are a family of four structurally related growth factors that are expressed in the developing and adult brain. NRG-1 is essential for normal heart formation and has been implicated in the development and maintenance of both neurons and glia. NRG-2 was identified on the basis of its homology to NRG-1 and, like NRG-1, is expressed predominantly by neurons in the central nervous system. We have generated mice with the active domain of NRG-2 deleted in an effort to characterize the biological function of NRG-2 in vivo. In contrast to the NRG-1 knockout animals, NRG-2 knockouts have no apparent heart defects and survive embryogenesis. Mutant mice display early growth retardation and reduced reproductive capacity. No obvious histological differences were observed in the major sites of NRG-2 expression. Our results indicate that in vivo NRG-2 activity differs substantially from that of NRG-1 and that it is not essential for normal development in utero.
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Factores de Crecimiento Nervioso/deficiencia , Factores de Crecimiento Nervioso/genética , Animales , Secuencia de Bases , Encéfalo/crecimiento & desarrollo , ADN Complementario/genética , Femenino , Marcación de Gen , Genes erbB , Corazón/crecimiento & desarrollo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factores de Crecimiento Nervioso/fisiología , Proteínas del Tejido Nervioso/deficiencia , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/fisiología , Neurregulina-1 , FenotipoRESUMEN
PURPOSE: To investigate early retinal changes in a vascular endothelial growth factor (VEGF) transgenic mouse (tr029VEGF; rhodopsin promoter) with long-term damage that mimics nonproliferative diabetic retinopathy (NPDR) and mild proliferative diabetic retinopathy (PDR). METHODS: Rhodopsin and VEGF expression was assessed up to postnatal day (P)28. Vascular and retinal changes were charted at P7 and P28 using sections and wholemounts stained with hematoxylin and eosin or isolectin IB4 Griffonia simplicifolia Samples were examined using light, fluorescence, and confocal microscopy. RESULTS: Rhodopsin was detected at P5 and reached mature levels by P15; VEGF protein expression was transient, peaking at P10 to P15. In wild-type (wt) mice at P7, vessels had formed in the nerve fiber/retinal ganglion cell layer and showed a centroperipheral maturational gradient; some capillaries had formed a second bed on the vitread side of the inner nuclear layer (INL). By P28, the retinal vasculature had three mature capillary beds, the third abutting the sclerad aspect of the INL. In tr029VEGF mice, capillary bed formation was accelerated compared with that in wt, with abnormal vessels extending to the sclerad side of the INL by P7 and abnormally penetrating the photoreceptors by P28. Compared with P7, vascular lesions were more numerous at P28 when capillary dropout was also evident. At both stages, retinal layers were thinned most where abnormal vessel growth was greatest. CONCLUSIONS: Concomitant damage to the vasculature and neural retina at early stages in tr029VEGF suggest that both tissues are affected, providing opportunities to examine early cellular events that lead to long-term disease.
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Retinopatía Diabética/patología , Modelos Animales de Enfermedad , Fibras Nerviosas/patología , Retina/embriología , Células Ganglionares de la Retina/patología , Neovascularización Retiniana/patología , Vasos Retinianos/patología , Factor A de Crecimiento Endotelial Vascular/genética , Animales , Permeabilidad Capilar , Retinopatía Diabética/genética , Angiografía con Fluoresceína , Técnicas para Inmunoenzimas , Ratones , Ratones Transgénicos , Microscopía Confocal , ARN Mensajero/metabolismo , Retina/crecimiento & desarrollo , Neovascularización Retiniana/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rodopsina/genética , Regulación hacia ArribaRESUMEN
Expression of the transcription factor Pax6 was assessed immunohistochemically in embryonic chick retina during retino-tectal map formation. A low dorsal to high ventral gradient was found that correlated with expression of the axonal guidance cue EphB2. Furthermore, transfection of Pax6 into undifferentiated P19 cells up-regulated EphB2. The results raise the possibility that Pax6 is upstream of EphB2 and that its graded expression defines the dorso-ventral axis of the retino-tectal projection.
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Proteínas de Homeodominio/metabolismo , Retina/embriología , Animales , Axones/fisiología , Línea Celular , Embrión de Pollo , Embrión de Mamíferos/metabolismo , Desarrollo Embrionario y Fetal , Proteínas del Ojo , Proteínas de Homeodominio/fisiología , Inmunohistoquímica , Ratones , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box , Receptor EphB2/metabolismo , Proteínas Represoras , Colículos Superiores/embriología , Transfección , Regulación hacia ArribaAsunto(s)
Neovascularización Retiniana/genética , Neovascularización Retiniana/patología , Factor A de Crecimiento Endotelial Vascular/genética , Animales , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Transgénicos , Microscopía Confocal , Retina/metabolismo , Rodopsina/genética , Factores de Tiempo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
We report 16 polymorphic microsatellite loci from Heliocidaris erythrogramma, a common sea urchin endemic to temperate Australian waters. These microsatellites were tested in a minimum of 30 individuals, which yielded between five and 14 alleles per locus. Expected heterozygosity ranged from 0.52 to 0.92 with four loci deviating from Hardy-Weinberg expectations. These markers are expected to be useful for experimental studies involving paternity analysis and for quantifying population structure in H. erythrogramma across its geographic range.
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During development, ephrin gradients guide retinal ganglion cell axons to their appropriate topographic locations in the superior colliculus (SC). Expression of ephrin-A2, assessed immunohistochemically in the developing hamster SC, revealed a rostral(low) to caudal (high) gradient that is most prominent at postnatal days P4 and P7 when topography is established. Double-labelling immunohistochemistry for ephrin-A2 and cell specific markers revealed that ephrin-A2 is expressed exclusively by a subset of neurons. The expression pattern has implications for mechanisms underlying establishment of topography during development and following injury.