Search results for "Interactions"
showing 10 items of 1963 documents
Early Development of the Gut Microbiota and Immune Health
2014
In recent years, the increase in human microbiome research brought about by the rapidly evolving “omic” technologies has established that the balance among the microbial groups present in the human gut, and their multipronged interactions with the host, are crucial for health. On the other hand, epidemiological and experimental support has also grown for the ‘early programming hypothesis’, according to which factors that act in utero and early in life program the risks for adverse health outcomes later on. The microbiota of the gut develops during infancy, in close interaction with immune development, and with extensive variability across individuals. It follows that the specific process of…
Metagenomic Survey of the Highly Polyphagous Anastrepha ludens Developing in Ancestral and Exotic Hosts Reveals the Lack of a Stable Microbiota in La…
2021
We studied the microbiota of a highly polyphagous insect, Anastrepha ludens (Diptera: Tephritidae), developing in six of its hosts, including two ancestral (Casimiroa edulis and C. greggii), three exotic (Mangifera indica cv. Ataulfo, Prunus persica cv. Criollo, and Citrus x aurantium) and one occasional host (Capsicum pubescens cv. Manzano), that is only used when extreme drought conditions limit fruiting by the common hosts. One of the exotic hosts (“criollo” peach) is rife with polyphenols and the occasional host with capsaicinoids exerting high fitness costs on the larvae. We pursued the following questions: (1) How is the microbial composition of the larval food related to the composit…
Optimum combination therapy regimens for HIV/HCV infection
2016
HIV-HCV co-infection mostly affects intravenous drug users, in whom prevalence has tended to decrease in recent years, while it has increased in men who have sex with men, with occurrence of acute hepatitis C. Hepatitis C has a poorer prognosis in patients co-infected with HIV, as clinical progression is faster and degree of hepatic fibrosis is greater. However, optimized ARV treatment is clearly associated with slower progression to hepatic complications. Interactions between HCV and HIV drugs are numerous, which underlines the importance of pharmacological advice for HIV-treated patients before they start HCV treatment. In HIV-HCV co-infection, treatment of hepatitis C has to be offered a…
Social evolution of innate immunity evasion in a virus
2019
Antiviral immunity has been studied extensively from the perspective of virus−cell interactions, yet the role of virus−virus interactions remains poorly addressed. Here, we demonstrate that viral escape from interferon (IFN)-based innate immunity is a social process in which IFN-stimulating viruses determine the fitness of neighbouring viruses. We propose a general and simple social evolution framework to analyse how natural selection acts on IFN shutdown and validate it in cell cultures and mice infected with vesicular stomatitis virus. Furthermore, we find that IFN shutdown is costly because it reduces short-term viral progeny production, thus fulfilling the definition of an altruistic tr…
Repeatability of Feather Mite Prevalence and Intensity in Passerine Birds
2014
Understanding why host species differ so much in symbiont loads and how this depends on ecological host and symbiont traits is a major issue in the ecology of symbiosis. A first step in this inquiry is to know whether observed differences among host species are species-specific traits or more related with host-symbiont environmental conditions. Here we analysed the repeatability (R) of the intensity and the prevalence of feather mites to partition within- and among-host species variance components. We compiled the largest dataset so far available: 119 Paleartic passerine bird species, 75,944 individual birds, ca. 1.8 million mites, seven countries, 23 study years. Several analyses and appro…
Comprehensive yeast genome database (CYGD)
2015
Information on the molecular structure and functional network of the entirely sequenced, well-studied model eukaryote, the budding yeast Saccharomyces cerevisiae. In addition the data of various projects on related yeasts are used for comparative analysis.
Intercalation of daunomycin into stacked DNA base pairs. DFT study of an anticancer drug
2008
We have computationally studied the intercalation of the antitumor drug daunomycin into six stacks of Watson-Crick DNA base pairs i.e., AT-AT, AT-TA, GC-AT, CG-TA, GC-GC, GC-CG) using density functional theory (DFT). The proton affinity of the DNA intercalater daunomycin in water was computed to be 159.2 kcal/mol at BP86/TZ2P, which is in line with the experimental observation that daunomycin is protonated under physiological conditions. The intercalation interaction of protonated daunomycin with two stacked DNA base pairs was studied through a hybrid approach in which intercalation is treated at LDA/TZP while the molecular structure of daunomycin and hydrogen-bonded Watson-Crick pairs is c…
The Surfactant Peptide KL4 Sequence Is Inserted with a Transmembrane Orientation into the Endoplasmic Reticulum Membrane
2008
AbstractSurfactant protein B (SP-B) is an essential component of pulmonary surfactant. Synthetic surfactant peptide KL4, a peptide based on a C-terminal amphipathic helical region of human SP-B, efficiently mimics some functional properties of SP-B and is included in therapeutic surfactant preparations used in trials to treat respiratory distress syndrome. The membrane orientation of this peptide is controversial. We used an in vitro transcription-translation system to study the insertion of hydrophobic sequences into microsomal membranes, and showed that the KL4 sequence integrates efficiently with a transmembrane orientation despite the presence of intermittent lysines throughout the sequ…
Charge Pair Interactions in Transmembrane Helices and Turn Propensity of the Connecting Sequence Promote Helical Hairpin Insertion
2013
alpha-Helical hairpins, consisting of a pair of closely spaced transmembrane (TM) helices that are connected by a short interfacial turn, are the simplest structural motifs found in multi-spanning membrane proteins. In naturally occurring hairpins, the presence of polar residues is common and predicted to complicate membrane insertion. We postulate that the pre-packing process offsets any energetic cost of allocating polar and charged residues within the hydrophobic environment of biological membranes. Consistent with this idea, we provide here experimental evidence demonstrating that helical hairpin insertion into biological membranes can be driven by electrostatic interactions between clo…
A New Heterogeneous Catalyst Obtained via Supramolecular Decoration of Graphene with a Pd2+ Azamacrocyclic Complex
2019
A new G-(H2L)-Pd heterogeneous catalyst has been prepared via a self-assembly process consisting in the spontaneous adsorption, in water at room temperature, of a macrocyclic H2L ligand on graphene (G) (G + H2L = G-(H2L)), followed by decoration of the macrocycle with Pd2+ ions (G-(H2L) + Pd2+ = G-(H2L)-Pd) under the same mild conditions. This supramolecular approach is a sustainable (green) procedure that preserves the special characteristics of graphene and furnishes an efficient catalyst for the Cu-free Sonogashira cross coupling reaction between iodobenzene and phenylacetylene. Indeed, G-(H2L)-Pd shows an excellent conversion (90%) of reactants into diphenylacetylene under mild conditio…