Search results for " receptor"

Ion-Pair Complexation with Dibenzo[21]Crown-7 and Dibenzo[24]Crown-8 bis-Urea Receptors

2016

Synthesis and ion-pair complexation properties of novel ditopic bis-urea receptors based on dibenzo[21]crown-7 (R(1) ) and dibenzo[24]crown-8 (R(2) ) scaffolds have been studied in the solid state, solution, and gas phase. In a 4:1 CDCl3 /[D6 ]DMSO solution, both receptors clearly show positive heterotropic cooperativity toward halide anions when complexed with Rb(+) or Cs(+) , with the halide affinity increasing in order I(-) <Br(-) <Cl(-) . In solution, the rubidium complexes of both receptors have higher halide affinities compared to the caesium complexes. However, Rb(+) and Cs(+) complexes of R(2) show stronger affinities toward all the studied anions compared to the corresponding catio…

The Cu(II) complex of a C-lipophilized 13aneN4 macrocycle with an additional protonable amino group as micellar anion receptor.

2009

Three 13aneN4 macrocyclic ligands have been prepared bearing a -CH(2)NHR side arm (R = H, n-C(5)H(11), n-C(10)H(21)) on a carbon atom. When Cu(2+) is complexed in the macrocyclic ring, the amino group of the side arm undergoes an acid-base protonation equilibrium but it is not able to coordinate apically the metal cation even when it is deprotonated. The Cu(2+) complex with the ligand bearing the longest appended aliphatic chain is fully confined inside Triton X-100 micelles, and its ability to bind and sequestrate a series of anions inside micelles has been studied at two different pH values, i.e. both with protonated and neutral side-arm amino group. The favourable role played by the prot…

Linking species habitat and past palaeoclimatic events to evolution of the teleost innate immune system

2017

Host-intrinsic factors as well as environmental changes are known to be strong evolutionary drivers defining the genetic foundation of immunity. Using a novel set of teleost genomes and a time-calibrated phylogeny, we here investigate the family of Toll-like receptor ( TLR ) genes and address the underlying evolutionary processes shaping the diversity of the first-line defence. Our findings reveal remarkable flexibility within the evolutionary design of teleost innate immunity characterized by prominent TLR gene losses and expansions. In the order of Gadiformes, expansions correlate with the loss of major histocompatibility complex class II ( MHCII ) and diversifying selection analyses sup…

Stabilizing selection on microsatellite allele length at arginine vasopressin 1a receptor and oxytocin receptor loci

2017

The loci arginine vasopressin receptor 1a ( avpr1a ) and oxytocin receptor ( oxtr ) have evolutionarily conserved roles in vertebrate social and sexual behaviour. Allelic variation at a microsatellite locus in the 5′ regulatory region of these genes is associated with fitness in the bank vole Myodes glareolus . Given the low frequency of long and short alleles at these microsatellite loci in wild bank voles, we used breeding trials to determine whether selection acts against long and short alleles. Female bank voles with intermediate length avpr1a alleles had the highest probability of breeding, while male voles whose avpr1a alleles were very different in length had reduced probability of …

Survival and gene expression under different temperature and humidity regimes in ants

2017

Short term variation in environmental conditions requires individuals to adapt via changes in behavior and/or physiology. In particular variation in temperature and humidity are common, and the physiological adaptation to changes in temperature and humidity often involves alterations in gene expression, in particular that of heat-shock proteins. However, not only traits involved in the resistance to environmental stresses, but also other traits, such as immune defenses, may be influenced indirectly by changes in temperature and humidity. Here we investigated the response of the ant F. exsecta to two temperature regimes (20 degrees C & 25 degrees C), and two humidity regimes (50% & 75%), for…

A Model for ERD2 Function in Higher Plants

2020

ER lumenal proteins have a K(H)DEL motif at their C-terminus. This is recognized by the ERD2 receptor (KDEL receptor in animals), which localizes to the Golgi apparatus and serves to capture escaped ER lumenal proteins. ERD2-ligand complexes are then transported back to the ER via COPI coated vesicles. The neutral pH of the ER causes the ligands to dissociate with the receptor being returned to the Golgi. According to this generally accepted scenario, ERD2 cycles between the ER and the Golgi, although it has been found to have a predominant Golgi localization. In this short article, we present a model for the functioning of ERD2 receptors in higher plants that explains why it is difficult t…

A self-inducible heterologous protein expression system in Escherichia coli

2016

AbstractEscherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter’s transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG inducti…

Successive Losses of Central Immune Genes Characterize the Gadiformes' Alternate Immunity.

2016

Great genetic variability among teleost immunomes, with gene losses and expansions of central adaptive and innate components, has been discovered through genome sequencing over the last few years. Here, we demonstrate that the innate Myxovirus resistance gene (Mx) is lost from the ancestor of Gadiformes and the closely related Stylephorus chordatus, thus predating the loss of Major Histocompatibility Complex class II (MHCII) in Gadiformes. Although the functional implication of Mx loss is still unknown, we demonstrate that this loss is one of several ancient events appearing in successive order throughout the evolution of teleost immunity. In particular, we find that the loss of Toll-like r…

2021

Both plants and animals are endowed with sophisticated innate immune systems to combat microbial attack. In these multicellular eukaryotes, innate immunity implies the presence of cell surface receptors and intracellular receptors able to detect danger signal referred as damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). Membrane-associated pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs), C-type lectin receptors (CLRs), receptor-like kinases (RLKs), and receptor-like proteins (RLPs) are employed by these organisms for sensing different invasion patterns before triggering antimicrobial defenses that can be associated with…

Structural and transcriptional evidence of mechanotransduction in the Drosophila suzukii ovipositor

2020

Drosophila suzukii is an invasive pest that prefers to lay eggs in ripening fruits, whereas most closely related Drosophila species exclusively use rotten fruit as oviposition site. This behaviour is allowed by an enlarged and serrated ovipositor that can pierce intact fruit skin, and by multiple contact sensory systems (mechanosensation and taste) that detect the optimal egg-laying substrates. Here, we tested the hypothesis that bristles present in the D. suzukii ovipositor tip contribute to these sensory modalities. Analysis of the bristle ultrastructure revealed that four different types of cuticular elements (conical pegs type 1 and 2, chaetic and trichoid sensilla) are present on the t…