Fish otoliths from the Priabonian (Late Eocene) of North Italy and South-East France - Their paleobiogeographical significance

The study of the Late Eocene (Priabonian) otolith associations from Possagno, North-East Italy, and from the Synclinal d’Allons in Haute Provence, South-East France, allows for the reconstruction of a teleost fauna of 55 taxa, which is the most diversified assemblage presently known from the Upper Eocene Paleo-Mediterranean basin. Thirty-six taxa are identified at the species level, and five of those are new: “genus Alepocephalidarum” astrictus, “genus Lophiiformorum” canovae, “genus Agonidarum” sudans, “genus Uranoscopidarum” cochlearis and Aseraggodes laganum. In the Synclinal d’Allons, the otolith associations reflect a tropical to subtropical neritic environment with a few mesopelagic fishes. At Possagno, the associations indicate an environment that changed from one that was deep and exposed to the pelagic realm and then evolved to a more shallow sea with a well-diversified benthic life and less mesopelagic fishes. A paleobiogeographical analysis of all known data on Priabonian otoliths, worldwide, shows clearly a western Atlantic (Louisiana) and an eastern Atlantic-Paleomediterranean association. In the eastern Atlantic-Paleomediterranean association, the Aquitaine association not only differs from the Possagno-Allons association in function of its more distant geographical position, but also by its stronger oceanic character in the southern part of the basin, and by the occurrence in the north, of a very shallow water facies (Saint-Estephe Formation) that contains some taxa which are known nowhere else in the Priabonian. The Ukraine fauna is characterized by a high number of species, which have an Oligocene record in other European sites. The northern geographic location of Ukraine, combined with the good connections to both the North Sea Basin and the Turgai street can provide the explanation. Many Oligocene species (or their close relatives) probably already existed at Eocene times in more northern regions, but could penetrate only in more southern European seas since the strong cooling at the beginning of the Oligocene.     

A new basal sauropodiform from South Africa and the phylogenetic relationships of basal sauropodomorphs

We present a new medium‐sized basal sauropodomorph, S efapanosaurus zastronensis gen. et sp. nov. , from the Upper Triassic?Lower Jurassic Elliot Formation of South Africa. It is represented by parts of the postcranial skeleton of at least four individuals, including: cervical, dorsal, sacral and caudal vertebrae, most of the forelimb, and part of the hindlimb. Sefapanosaurus bears several autapomorphies of the astragalus, and referred material also shows autapomorphic features. The inclusion of Sefapanosaurus in a phylogenetic analysis places it within the group of sauropodomorphs more closely related to sauropods than to Massospondylus (i.e. Sauropodiformes), increasing the currently known diversity of the so‐called ‘transitional forms’ leading to Sauropoda. Character optimization revealed the presence of several features that are common for taxa placed within the transitional branches basal to Sauropoda. Sefapanosaurus, together with other transitional sauropodomorphs reported during the last decade, highlights the importance of Gondwanan taxa for understanding the palaeobiodiversity, global distribution, and macroevolutionary changes in the group related to the rise of sauropods. © 2015 The Linnean Society of London     

Headwaters of the zebrafish -- emergence of a new model vertebrate

The understanding of vertebrate development has advanced considerably in recent years, primarily due to the study of a few model organisms. The zebrafish, the newest of these models, has risen to prominence because both genetic and experimental embryological methods can be easily applied to this animal. The combination of approaches has proven powerful, yielding insights into the formation and function of individual tissues, organ systems and neural networks, and into human disease mechanisms. Here, we provide a personal perspective on the history of zebrafish research, from the assembly of the first genetic and embryological tools through to sequencing of the genome.     

Decline of the marabou stork (Leptoptilos crumenifer) in West Africa and the need for immediate conservation action

The marabou stork (Leptoptilos crumenifer) is widespread and generally abundant in East and Southern Africa, but recent research has found range loss indicative of a population decline in West Africa in recent decades. In the absence of population data, we conducted an in-depth review of the status of the marabou in the region using a plethora of sources together comprising the largest database on the occurrence of the species. Despite caveats and coarseness of the assessment, we estimate the range loss at 52% in West Africa, including extirpation of approximately 64% of known nesting colonies since 2000. The resulting fragmentation has left a metapopulation of likely no more than 100 breeding pairs in The Gambia and Benin and an unknown number of breeders in Cameroon. Knowledge gaps about marabou population ecology in West Africa are significant and prevent an empirical assessment of regional extinction probability. Therefore, we recommend immediate field surveys, especially for breeding colonies, and research into threats and population dynamics. We also recommend the West African metapopulation be listed as regionally critically endangered and that a working group be formed comprising stakeholders from across the region to aid in assessing threats and implementing research and conservation action.     

Effects of concrete properties and nutrients on fungal colonization and fouling

This study describes the fouling of concrete surfaces by diverse fungal genera under controlled laboratory conditions. A circulating flow-through chamber was designed for testing the effects of different concrete compositions and exogenously added nutrients on fungal colonization and fouling. Fungal strains belonging to the genera Alternaria, Cladosporium, Epicoccum, Fusarium, Mucor, Penicillium, Pestalotiopsis, and Trichoderma were cultured directly from visibly fouled concrete structures and used individually and in a mix to inoculate mortar tiles varying in cement composition, supplementary cementitious material additions, water-to-cement ratio, and surface roughness. A strong positive relationship was observed between tile water-to-cement ratio and the amount of biofouling. In addition, cement containing photocatalytic titanium dioxide and exposed to artificial sunlight strongly inhibited fungal colonization and fouling. Mortar tiles coated with form-release oil and incubated with sterile rainwater were also capable of supporting fungal colonization. Our results indicate that the fouling of concrete surfaces by fungi can be influenced by variations in concrete composition variations and available nutrients.     

Whole-cell voltage clamp measurements of anthrax toxin pore current

Protective antigen (PA) of anthrax toxin binds cellular receptors and forms pores in target cell membranes, through which catalytic lethal factor (LF) and edema factor (EF) are believed to translocate to the cytoplasm. Using patch clamp electrophysiological techniques, we assayed pore formation by PA in real time on the surface of cultured cells. The membranes of CHO-K1 cells treated with activated PA had little to no electrical conductivity at neutral pH (7.3) but exhibited robust mixed ionic currents in response to voltage stimuli at pH 5.3. Pore formation depended on specific cellular receptors and exhibited voltage-dependent inactivation at large potentials (>60 mV). The pH requirement for pore formation was receptor-specific as membrane insertion occurs at significantly different pH values when measured in cells specifically expressing tumor endothelial marker 8 (TEM8) or capillary morphogenesis protein 2 (CMG2), the two known cellular receptors for anthrax toxin. Pores were inhibited by an N-terminal fragment of LF and by micromolar concentrations of tetrabutylammonium ions. These studies demonstrated basic biophysical properties of PA pores in cell membranes and served as a foundation for the study of LF and EF translocation in vivo.     

House dust mite sensitization drives cross-reactive immune responses to homologous helminth proteins

The establishment of type 2 responses driven by allergic sensitization prior to exposure to helminth parasites has demonstrated how tissue-specific responses can protect against migrating larval stages, but, as a consequence, allow for immune-mediated, parasite/allergy-associated morbidity. In this way, whether helminth cross-reacting allergen-specific antibodies are produced and play a role during the helminth infection, or exacerbate the allergic outcome awaits elucidation. Thus, the main objective of the study was to investigate whether house dust mite (HDM) sensitization triggers allergen-specific antibodies that interact with Ascaris antigens and mediate antibody-dependent deleterious effects on these parasites as well as, to assess the capacity of cross-reactive helminth proteins to trigger allergic inflammation in house dust mite presensitized mice. Here, we show that the sensitization with HDM-extract drives marked IgE and IgG1 antibody responses that cross-react with Ascaris larval antigens. Proteomic analysis of Ascaris larval antigens recognized by these HDM-specific antibodies identified Ascaris tropomyosin and enolase as the 2 major HDM homologues based on high sequence and structural similarity. Moreover, the helminth tropomyosin could drive Type-2 associated pulmonary inflammation similar to HDM following HDM tropomyosin sensitization. The HDM-triggered IgE cross-reactive antibodies were found to be functional as they mediated immediate hypersensitivity responses in skin testing. Finally, we demonstrated that HDM sensitization in either B cells or FcγRIII alpha-chain deficient mice indicated that the allergen driven cell-mediated larval killing is not antibody-dependent. Taken together, our data suggest that aeroallergen sensitization drives helminth reactive antibodies through molecular and structural similarity between HDM and Ascaris antigens suggesting that cross-reactive immune responses help drive allergic inflammation.     

Gray‐headed Lemur (Eulemur cinereiceps) Abundance and Forest Structure Dynamics at Manombo,Madagascar

Madagascar's ecosystems are subject to high levels of anthropogenic disturbance and stochastic events, including cyclones. We investigated the abundance of gray‐headed lemurs (Eulemur cinereiceps) and vegetation structure in the fragmented forest of Manombo from 1995 to 2007, including 10 yr following Cyclone Gretelle in January 1997. We predicted that the density of this arboreal, frugivorous lemur would be similar in the pre‐ and post‐cyclone intervals only if tree measures demonstrate trends toward recovery in the post‐cyclone period. Initial impacts included severe damage to over 60 percent of trees. After 10 yr, all vegetation metrics except for stem density remained low relative to the pre‐cyclone period, including dbh, height, and basal area. To investigate vegetation changes separately from cyclone effects, we compared forest structure in the pre‐cyclone period alone. Basal area declined but dbh and stem density did not vary between 1995 and 1997; thus, anthropogenic activities or other factors did not consistently alter forest structure in this 2‐yr period. Subsequent changes may be linked to cyclone response, presumably in synergy with human disturbance. Contrary to predictions, recent gray‐headed lemur population densities were nearly identical to those recorded in 1995 (13.5 ± 3.2 vs. 13.6 ± 6.4 individuals/km², respectively). Lemur populations may have remained stable or declined initially and then recovered in the last 10 yr. Life history and ecological adaptations may explain their resistance or resilience when faced with habitat change. Recent models suggest that lemurs have evolved in response to unpredictable environmental conditions. Such environmental variability may increase with projected climate change.