A revision of Aceratherium blanfordi Lydekker, 1884 (Mammalia: Rhinocerotidae) from the Early Miocene of Pakistan: postcranials as a key

Rhinocerotids are particularly abundant and diversified in Neogene deposits of the Indian subcontinent, but their systematics is far from being well defined. Based on the revision of old collections and new findings from the Early Miocene of the Bugti Hills and Zinda Pir, Pakistan, ‘Aceratherium blanfordi Lydekker, 1884’ is a chimera, consisting of two dentally convergent but postcranially distinct rhinocerotid taxa: Pleuroceros blanfordi and Mesaceratherium welcommi sp. nov. Postcranial features appear to be much more diagnostic than craniodental morphology in this case. A phylogenetic analysis based on 282 morphological characters scored for 28 taxa (four outgroups and ingroup including both taxa of interest and a ‘branching group’) strengthens this statement and supports Pleuroceros and Mesaceratherium as monophyletic genera within Rhinocerotinae. Both genera are recognized for the first time outside Europe. In the Bugti Hills, P. blanfordi and M. welcommi are part of an exceptionally diversified rhinocerotid fauna, with up to nine species associated in the same locality (Kumbi 4f). This rhinocerotid assemblage confirms the earliest Miocene age (Agenian/Aquitanian) of the upper member of the Chitarwata Formation as a whole. Coeval homotaxic rhinocerotid faunas from Europe (France, Czech Republic) and East Africa (Uganda, Kenya) support broad and sustainable rhinocerotid interchanges amongst South Asia, Europe, and Africa under compatible environmental conditions throughout earliest Miocene times. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 139–194.     

In vitro production of cat blastocysts of predetermined sex using flow cytometrically sorted semen

Sex preselection in cats can have applications for both breeding purposes and as an experimental model for endangered felids. The present study examined the ability to produce cat embryos from in vitro fertilization (IVF) of in vitro matured (IVM) cat oocytes with flow cytometrically sorted spermatozoa and to verify the sex of the embryos obtained from sexed spermatozoa by PCR. In the first experiment, a total of 224 oocytes were fertilized with spermatozoa from six ejaculates sorted without sex separation. The sorting process did not influence the cleavage rate (sorted 44.0% versus unsorted 46.1%), day 6 morula-blastocyst rate (sorted 26.6% versus unsorted 29.6%) and day 7 blastocyst rate (sorted 16.5% versus unsorted 16.5%). In the second experiment, a total of 84 IVM oocytes were fertilized with sorted X- and Y-chromosome bearing spermatozoa from four ejaculates in order to obtain embryos of preselected sex. Embryonic sex determination by PCR revealed that 21 out of 24 embryos reaching morula/blastocyst stage (87.5%) were of the desired sex. In particular 12 out of 14 embryos (85.7%) derived from X-bearing spermatozoa were female and 9 embryos out of 10 (90%) derived from Y-bearing spermatozoa were male. Our results show, for the first time, that X- and Y-chromosome bearing spermatozoa sorted by high-speed flow cytometry can be successfully used in an IVM-IVF system to obtain cat embryos of a predetermined sex.     

Separating the wheat from the chaff: a prioritisation pipeline for the analysis of metabolomics datasets

Liquid Chromatography Mass Spectrometry (LC-MS) is a powerful and widely applied method for the study of biological systems, biomarker discovery and pharmacological interventions. LC-MS measurements are, however, significantly complicated by several technical challenges, including: (1) ionisation suppression/enhancement, disturbing the correct quantification of analytes, and (2) the detection of large amounts of separate derivative ions, increasing the complexity of the spectra, but not their information content. Here we introduce an experimental and analytical strategy that leads to robust metabolome profiles in the face of these challenges. Our method is based on rigorous filtering of the measured signals based on a series of sample dilutions. Such data sets have the additional characteristic that they allow a more robust assessment of detection signal quality for each metabolite. Using our method, almost 80% of the recorded signals can be discarded as uninformative, while important information is retained. As a consequence, we obtain a broader understanding of the information content of our analyses and a better assessment of the metabolites detected in the analyzed data sets. We illustrate the applicability of this method using standard mixtures, as well as cell extracts from bacterial samples. It is evident that this method can be applied in many types of LC-MS analyses and more specifically in untargeted metabolomics.

     

Future climate‐driven shifts in distribution of Calanus finmarchicus

Calanus finmarchicus is a key‐structural species of the North Atlantic polar biome. The species plays an important trophic role in subpolar and polar ecosystems as a grazer of phytoplankton and as a prey for higher trophic levels such as the larval stages of many fish species. Here, we used a recently developed ecological niche model to assess the ecological niche (sensu Hutchinson) of C. finmarchicus and characterize its spatial distribution. This model explained about 65% of the total variance of the observed spatial distribution inferred from an independent dataset (data of the continuous plankton recorder survey). Comparisons with other types of models (structured population and ecophysiological models) revealed a clear similarity between modeled spatial distributions at the scale of the North Atlantic. Contemporary models coupled with future projections indicated a progressive reduction of the spatial habitat of the species at the southern edge and a more pronounced one in the Georges Bank, the Scotian Shelf and the North Sea and a potential increase in abundance at the northern edge of its spatial distribution, especially in the Barents Sea. These major changes will probably lead to a major alteration of the trophodynamics of North Atlantic ecosystems affecting the trophodynamics and the biological carbon pump.     

Effect of EGF on in vitro maturation of domestic cat oocytes

The objective of this study was to evaluate the influence of different concentrations of epidermal growth factor (EGF) on in vitro maturation of domestic cat oocytes. A total of 444 cat oocytes were matured in MSOF (maturation synthetic oviductal fluid) in the presence of varying EGF concentrations: (1) MSOF (control); (2) MSOF+10 ng/mL EGF (EGF10); (3) MSOF+25 ng/mL EGF (EGF25); and (4) MSOF+50 ng/mL EGF (EGF50). After IVM, oocytes were in vitro fertilized to verify the effect of adding EGF on cytoplasmic maturation. Cleavage rate was recorded and noncleaving oocytes were stained with Hoechst 33258 and examined to determine nuclear maturation rate. Cleaved zygotes were cultured in vitro and embryo stages were evaluated on days 6 and 7. There was no difference among groups in the total number of oocytes reaching the metaphase II (MII) stage (P>0.05). The EGF25 group had the highest (P<0.01) blastocyst yield (37.5%) and developmental competence (60.9%). Cleavage rate and resulting morulae and blastocysts on day 6 for EGF25 group were higher (P<0.01) than control and EGF50 groups. Although EGF did not significantly enhance nuclear maturation rate, it had a dose-related positive effect on cytoplasmic maturation, since the oocyte's ability to cleave and reach the blastocyst stage was improved at 25 ng/mL, with intermediate improvement at 10 ng/mL, but 50 ng/mL had no significant benefit. In conclusion, the addition of EGF to the maturation medium enhanced cytoplasmic maturation of cat oocytes in vitro.