Browsing by Subject "Mammals"

Now showing 1 - 3 of 3
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    ¿Drenajes de carreteras o pasos de fauna?: la conectividad oculta de vertebrados terrestres bajo infraestructuras lineales de transporte
    (Asociación Española de Ecología Terrestre, 2025-04-08) Bruno, Daniel; Mora, Ramón; Estal, Goodwill; Pujante, Nuria; Audisio, Carolina; Giménez, Andrés; Jiménez Franco, María Victoria; Ecología e Hidrología; Facultades de la UMU::Facultad de Biología
    Habitat fragmentation is one of the greatest threats to biodiversity. Linear transport infrastructures, such as roads, are one of the main causes of habitat fragmentation and may be corrected by wildlife crossings, although their implementation is still scarce. However, drainage culvert under linear transport infrastructures could indirectly act as wildlife crossings by increasing landscape connectivity. Our aim is to identify which vertebrate species crossroad drains in a protected area in Almería (SE Spain). For this purpose, camera traps were installed in 8 transversal drainage culverts during a complete year (2023-2024), analysing the crossing events by different vertebrate species as well as their spatial and temporal patterns. The results showed that the drainage culverts can be used as wildlife crossings by vertebrate species of interest including mammals (e.g. Capra pyrenaica, Eliomys quercinus, Felis silvestris, Oryctolagus cuniculus) and reptiles (Testudo graeca, Timon nevadensis). An increase in vertebrate crossing rates was detected during the months of May-June and September-October. Most of the crossing events by mammals occurred at night, whereas those of ectotherms such as reptiles were detected during the day. We reported the first detections of T. graeca, an endangered reptile in Andalusia (Spain), crossing drainage culverts or non-wildlife crossing under a linear transport infrastructure in its whole distribution range. We conclude that in the absence of suitable and specific wildlife crossings, which need to be increasingly implemented in the short term, road culverts could have potential to improve the connectivity of vertebrate populations, including endangered species.
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    Mad2 and spindle assembly checkpoint function during meiosis I in mammalian oocytes
    (Murcia : F. Hernández, 2006) Homer, H.A.
    During mammalian mitosis, a proofreading network called the spindle assembly checkpoint (SAC) is indispensable for ensuring the fidelity of chromosome segregation. An inhibitory SAC signal is deputed to inhibits mitotic cell-cycle progression in response to misaligned chromosomes until such imperfections are rectified thereby ensuring equitable chromosome partitioning to daughter cells. Amongst the cast of SAC proteins, mitotic arrest deficient 2 (Mad2) plays a leading role in transducing the SAC signal. The aneuploidy and cancer predispositions of individuals who harbour genetic mutations in SAC genes emphasise the in vivo significance of this surveillance mechanism. In humans, congenital aneuploidies such as Down’s syndrome demonstrate an exponential increase with advancing female age. Although largely the result of female meiosis I errors, the molecular entities that succumb with age in oocytes remain elusive. Declining oocyte SAC function could plausibly contribute to such errors. Until recently however, convincing evidence for a functional SAC in mammalian oocytes during meiosis I was unforthcoming. Here I review the evidence regarding the SAC in female mammalian meiosis I and how our understanding of this system has evolved in recent years. This review will focus on Mad2 as this is the SAC protein that has been most comprehensively investigated.
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    New Insights into the Mammalian Egg Zona Pellucida
    (2021) Chevret, Pascale; Algarra, Blanca; González-Brusi, Leopoldo; Cots Rodríguez, Paula; Izquierdo Rico, María José; Avilés Sánchez, Manuel; Jíménez Movilla, María; Moros Nicolás, Carla; Biología Celular e Histología
    Mammalian oocytes are surrounded by an extracellular coat called the zona pellucida (ZP), which, from an evolutionary point of view, is the most ancient of the coats that envelope vertebrate oocytes and conceptuses. This matrix separates the oocyte from cumulus cells and is responsible for species-specific recognition between gametes, preventing polyspermy and protecting the preimplantation embryo. The ZP is a dynamic structure that shows different properties before and after fertilization. Until very recently, mammalian ZP was believed to be composed of only three glycoproteins, ZP1, ZP2 and ZP3, as first described in mouse. However, studies have revealed that this composition is not necessarily applicable to other mammals. Such differences can be explained by an analysis of the molecular evolution of the ZP gene family, during which ZP genes have suffered pseudogenization and duplication events that have resulted in differing models of ZP protein composition. The many discoveries made in recent years related to ZP composition and evolution suggest that a compilation would be useful. Moreover, this review analyses ZP biosynthesis, the role of each ZP protein in different mammalian species and how these proteins may interact among themselves and with other proteins present in the oviductal lumen.