Characterization and Reconstitution of S-Palmitoylated IFITM3 Antiviral Activity

To rapidly detect early stage infections the innate immune system maintains an assortment of pathogen recognition mechanisms interspersed throughout both the extracellular and intracellular environments. These sensors recognize key components of viral, bacterial and fungal pathogens, and stimulate an inflammatory response which leads to the expression of an extensive network of host defense proteins. One such canonical network is regulated by type I interferon. This pathway responds to viral infections by upregulating hundreds of interferon stimulated genes (ISG) critical for host immunity. One of the more pivotal proteins for viral control is interferon-induced transmembrane protein 3 (IFITM3). IFITM3 is a host protein known to play a key role in inhibiting numerous virus infections, including influenza, Dengue, West Nile, HIV and Ebola. It is active in the early stages of infection and interferes with viral fusion and content delivery to the cell cytoplasm. Despite this broad antiviral activity, the exact mechanism of IFITM3 viral fusion interference, and whether it directly interacts with the fusion environment remains unknown. To better understand the physiological conditions of IFITM3 antiviral activity, we required an improved understanding of the endogenous levels of S-fatty acylation. While earlier work in our lab has shown this post-translational modification to be critical for IFITM3 activity, it was previously impossible to distinguish between different modified populations. I therefore developed the acyl PEG exchange (APE) assay. Utilizing cysteine selective mass tags, APE detects different levels of fatty acylated cysteines within a protein population, which allows us to probe the lipidated states of endogenous proteins for the first time. Using this assay, I have shown that the majority of endogenous human IFITM3 is dually S-fatty acylated. To investigate the mechanism of IFITM3 antiviral activity, I generated recombinant, native, synthetically lipidated protein for structural and fusion-based studies. We applied an in vitro viral fusion model that detects the lipid mixing of viral envelopes with liposomes. We demonstrate that viral fusion is mitigated with the inclusion of recombinant IFITM3 liposomes. Furthermore, when IFITM3 is modified with maleimide palmitate to mimic fatty-acylation at cysteine 105, lipid mixing is inhibited more than the unmodified IFITM3. Overall, our recombinant model of viral fusion provides an in vitro approach to investigate IFITM3 function. The assay provides the first evidence that IFITM3 directly alters the membrane fusion environment, and that cysteine palmitoylation enhances protein function as well. In the future, these studies will be complemented with more accurate in vitro assays to further elucidate its critical mechanism

Too Much of a Good Thing? Female Sterilization in India: a Literature Review

India has the largest number of sterilized women in the world; as of 2005-06, two thirds of Indian women of reproductive age had undergone sterilization. This paper reviewed literature both from peer-reviewed publications and soft literature to understand issues surrounding such pervasive use of the method. Four major thematic areas emerged: the use of incentives and targets in promoting female sterilization (FS), socio-demographic factors influencing FS use, quality of care in sterilization camps, and sterilization regret. Following the advice of public health advocates, the government should commit to improving informed choice and access to a variety of methods as well as increase efforts to educate on and provide vasectomy services. Future academic research should address the use of incentives and targets in promoting FS at the expense of other methods.Master of Public Healt

Methodological implications of intra- and inter-facet microwear texture variation for human childhood paleo-dietary reconstruction: Insights from the deciduous molars of extant and medieval children from France

The present study concerns occlusal dental microwear texture variation on the deciduous molars of children. A description and evaluation of microwear texture variation within facet 9 and a comparison of microwear textures between grinding facets 9 and 11 are presented. The relationship between wear facet surface area and intra-facet microwear texture variability is evaluated. The sample is composed of naturally-exfoliated, taphonomy-free deciduous second molars from twelve extant children and four archaeologically-derived medieval children (for a total of 51 surface measurements). Dental microwear texture analysis (DMTA) was performed using a confocal microscope and scale-sensitive fractal analysis (SSFA) at three standardized locations on facet 9, and one location on facet 11. Facet shape was visually assessed and scored using a headset magnifier (3×) and composite images (20× confocal microscopy). Individuals were assigned to two groups based on a qualitative assessment of facet surface area. Microwear texture variability within facet 9 was high relative to the variability of microwear textures between individuals. No significant inter-facet variation between facets 9 and 11 was detected. No clear differences in microwear and variabilities within facet 9 were found between individuals assigned to small and large facet groups. Our study shows the existence of important intra-facet microwear variation in a sample of children. Intra-facet microwear variation can affect the ability of DMTA to distinguish between diets in contexts with small sample sizes and subtle differences in diet – such as those characterizing dietary transitions in children. Results also suggest non-dietary factors may influence microwear formation during dental exfoliation. A better understanding of intra-facet microwear variation, and when and how to account for it, can improve the application of occlusal DMTA in similar contexts

Buccal dental-microwear and dietary ecology in a free-ranging population of mandrills (Mandrillus sphinx) from southern Gabon

Analyses of dental micro- and macro-wear offer valuable information about dietary adaptations. The buccal surface of the teeth does not undergo attrition, indicating that dental microwear may directly inform about food properties. Only a few studies have, however, investigated the environmental and individual factors involved in the formation of such microwear in wild animals. Here, we examine variation of buccal microwear patterns of mandibular molars in a large free-ranging population of mandrills (Mandrillus sphinx). We first explore the influence of seasonality and individual’s sex, age and tooth macrowear–expressed as the percent of dentine exposure (PDE)–on six microwear variables. Second, we analyze the interplay between individual’s diet and PDE. In a last analysis, we revisit our results on mandrills in the light of other primate’s microwear studies. We show that the average buccal scratch length and the frequency of vertical buccal scratches are both higher during the long dry season compared to the long rainy season, while we observe the inverse relationship for disto-mesial scratches. In addition, females present more disto-mesial scratches than males and older individuals present higher scratch density, a greater proportion of horizontal scratches but a lower proportion of vertical scratches than young animals. PDE yields similar results than individual’s age confirming earlier results in this population on the relationship between age and tooth macrowear. Because seasonality and individual characteristics are both known to impact mandrills’ diet in the study population, our results suggest that buccal microwear patterns may inform about individual feeding strategies. Furthermore, PDE increases with the consumption of potentially abrasive monocotyledonous plants, independently of the individuals’ age, although it is not affected by food mechanical properties. Finally, buccal scratch densities by orientation appear as relevant proxies for discriminating between different primate taxa.The Deutsche Forschungsgemeinschaft grant (DFG, KA 1082-20-1), the “Station d’Etudes en Ecologie Globale” (INEE-CNRS), the “Laboratoire International Associé” (CIRMF and INEE-CNRS), granted to MJEC, and the Spanish "Ministerio de Ciencia e Innovación" (grant numbers CGL2011-22999 and CGL2014-52611) granted to APP, have all contributed to the achievement of this study

Quantitative analysis of protein S-acylation site dynamics using site-specific acyl-biotin exchange (ssABE).

Protein S-acylation (palmitoylation) is a reversible lipid modification that is increasingly recognized as an important regulator of protein function, including membrane association, trafficking, and subcellular localization. Most proteomic methods to study palmitoylation allow characterization of putative palmitoylated proteins but do not permit identification of individual sites of palmitoylation. We have recently adapted the Acyl-Biotin Exchange (ABE) method that is routinely used for palmitoyl-proteome characterization, to permit global S-acylation site analysis. This site-specific ABE (ssABE) protocol, when combined with SILAC-based quantification, allows both the large-scale identification of palmitoylation sites and quantitative profiling of palmitoylation site changes. This approach enables palmitoylation to be studied at a systems level comparable to other more intensively studied post-translational modifications