Mass-spectrometry of single mammalian cells quantifies proteome heterogeneity during cell differentiation

Cellular heterogeneity is important to biological processes, including cancer and development. However, proteome heterogeneity is largely unexplored because of the limitations of existing methods for quantifying protein levels in single cells. To alleviate these limitations, we developed Single Cell ProtEomics by Mass Spectrometry (SCoPE-MS), and validated its ability to identify distinct human cancer cell types based on their proteomes. We used SCoPE-MS to quantify over a thousand proteins in differentiating mouse embryonic stem (ES) cells. The single-cell proteomes enabled us to deconstruct cell populations and infer protein abundance relationships. Comparison between single-cell proteomes and transcriptomes indicated coordinated mRNA and protein covariation. Yet many genes exhibited functionally concerted and distinct regulatory patterns at the mRNA and the protein levels, suggesting that post-transcriptional regulatory mechanisms contribute to proteome remodeling during lineage specification, especially for developmental genes. SCoPE-MS is broadly applicable to measuring proteome configurations of single cells and linking them to functional phenotypes, such as cell type and differentiation potentials

Palladium-Catalyzed Carboetherification and Carboamination Reactions of Γ-Hydroxy- and Γ-Aminoalkenes for the Synthesis of Tetrahydrofurans and Pyrrolidines

Substituted tetrahydrofuran and pyrrolidine moieties are displayed in a wide range of interesting biologically active molecules. The Pd-catalyzed carboetherification or carboamination of Γ-hydroxy and Γ-aminoalkenes is a powerful tool for the construction of these heterocycles, as it is convergent and can allow access to a variety of analogs from a single Γ-hydroxy- or Γ-aminoalkene starting material. This microreview describes the current state of this field. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55970/1/571_ftp.pd

Survivre en agrosystème céréalier - le défi de la Perdrix grise : sélection d’habitat, compétition interspécifique et traits individuels

Habitat selection is a behavioural process in response to environmental stimuli as resource availability (food, shelter) and threats(competitors, predators). The understanding of the underlying mechanisms is crucial in ecology and allow to identify and consider factors limiting populations. The stake of this PhD thesis was to identify limiting factors (landscapes, game practices) and reponses of grey partridge (Perdix perdix) populations under mixed game management (annual releases of captive-reared birds, without shooting suspension). Habitat selection patterns have changed towards a lower avoidance of risky habitats, while habitat suitability has decreased and the proportion of captive-reared birds in the population has likely increased. Interspecific competition with red-legged partridge also affected habitat selection in grey partridge. Some individuals showed a behavioural capacity to adjust (in terms of rhythms of activity, habitat selection, space use) to the spatiotemporal structuration of risk along the diel cycle, potentially influenced by individual traits (personality, health status). Habitat suitability, predation and hunting pressures were identified as structuring factors of grey partridge populations. A game management based on releases of naïve birds and competing species, disturbances induced by shooting during the post-release period, and no preliminary assessement of habitat quality, could locally imperil the maintenance of grey partridge populations.La sélection de l’habitat est définie comme un processus comportemental en réponse à des stimuli environnementaux tels que la disponibilité en ressources (alimentation, refuges)et la présence de menaces (compétiteurs, prédateurs). La compréhension des mécanismes sous-jacents est essentielle en écologie et permet d’identifier et d’appréhender les facteurs limitant les populations. L’enjeu de cette thèse était d’identifier les facteurs limitants (paysages, pratiques cynégétiques) et la réponse des populations de Perdrix grise (Perdix perdix) soumises à gestion cynégétique (apports annuels d’oiseaux d’élevage, sans arrêt de la chasse). Les patrons de sélection d’habitat ont varié vers un évitement moins prononcé des habitats associés à un fort risque de prédation, dans le même temps que la qualité d’habitat a diminué et que la prévalence d’oiseaux d’élevage a probablement augmenté dans la population. La compétition interspécifique avec la Perdrix rouge affecte également la sélection de l’habitat de la Perdrix grise. Certains individus démontrent une capacité d’ajustement comportemental (rythme d’activité,sélection de l’habitat, de l’espace) à la structuration du risque au cours du cycle circadien, possiblement influencée par des déterminants individuels (personnalité, état sanitaire). La qualité d’habitat, les pressions de prédation et de chasse sont des facteurs structurants des populations. Une gestion cynégétique basée sur l’apport d’oiseaux naïfs et d’espèces compétitrices, un dérangement lié à la chasse en phase post-lâcher et une non-évaluation préalable de la qualité de l’habitat, rendent le maintien des populations de Perdrix grise sur un territoire très incertain