Mafb and c-Maf Have Prenatal Compensatory and Postnatal Antagonistic Roles in Cortical Interneuron Fate and Function

1. Download high-res image (175KB)
2. Download full-size image

     

Thermal performance of quartz capillaries for vitrification

In this paper we report the thermal behavior of a new approach for vitrification. Thermal performance of traditional open pulled straws is compared with a new technique based on the combined use of quartz capillaries with slush nitrogen. This new method of vitrification achieved ultrafast cooling rates of 250,000 °C/min. As a result, a much lower concentration of cryoprotectant was needed to reach vitrification. In fact, a cryoprotectant solution typically used in oocyte slow freezing protocols was shown to remain transparent after cooling to liquid nitrogen temperatures indicating apparent “vitrification”. This approach offers a new and very promising technique for vitrification of cells using low levels of cryoprotectants.     

Glucose-6-phosphate as a probe for the glucosamine-6-phosphate N-acetyltransferase Michaelis complex

Glucosamine-6-phosphate N-acetyltransferase (GNA1) catalyses the N-acetylation of d-glucosamine-6-phosphate (GlcN-6P), using acetyl-CoA as an acetyl donor. The product GlcNAc-6P is an intermediate in the biosynthesis UDP-GlcNAc. GNA1 is part of the GCN5-related acetyl transferase family (GNATs), which employ a wide range of acceptor substrates. GNA1 has been genetically validated as an antifungal drug target. Detailed knowledge of the Michaelis complex and trajectory towards the transition state would facilitate rational design of inhibitors of GNA1 and other GNAT enzymes. Using the pseudo-substrate glucose-6-phosphate (Glc-6P) as a probe with GNA1 crystals, we have trapped the first GNAT (pseudo-)Michaelis complex, providing direct evidence for the nucleophilic attack of the substrate amine, and giving insight into the protonation of the thiolate leaving group.     

Eustress application trough-controlled elicitation strategies as an effective agrobiotechnology tool for capsaicinoids increase: a review

Phytochemistry Reviews - Capsaicinoids (CAPs) are compounds synthesized and accumulated exclusively in pepper fruits. They are known as health-promoting compounds, and upbringing approaches to...     

GCAT|Panel,a comprehensive structural variant haplotype map of the Iberian population from high-coverage whole-genome sequencing

The combined analysis of haplotype panels with phenotype clinical cohorts is a common approach to explore the genetic architecture of human diseases. However, genetic studies are mainly based on single nucleotide variants (SNVs) and small insertions and deletions (indels). Here, we contribute to fill this gap by generating a dense haplotype map focused on the identification, characterization, and phasing of structural variants (SVs). By integrating multiple variant identification methods and Logistic Regression Models (LRMs), we present a catalogue of 35 431 441 variants, including 89 178 SVs (≥50 bp), 30 325 064 SNVs and 5 017 199 indels, across 785 Illumina high coverage (30x) whole-genomes from the Iberian GCAT Cohort, containing a median of 3.52M SNVs, 606 336 indels and 6393 SVs per individual. The haplotype panel is able to impute up to 14 360 728 SNVs/indels and 23 179 SVs, showing a 2.7-fold increase for SVs compared with available genetic variation panels. The value of this panel for SVs analysis is shown through an imputed rare Alu element located in a new locus associated with Mononeuritis of lower limb, a rare neuromuscular disease. This study represents the first deep characterization of genetic variation within the Iberian population and the first operational haplotype panel to systematically include the SVs into genome-wide genetic studies.     

Microrheology of human lung epithelial cells measured by atomic force microscopy

Lung epithelial cells are subjected to large cyclic forces from breathing. However, their response to dynamic stresses is poorly defined. We measured the complex shear modulus (G(*)(omega)) of human alveolar (A549) and bronchial (BEAS-2B) epithelial cells over three frequency decades (0.1-100 Hz) and at different loading forces (0.1-0.9 nN) with atomic force microscopy. G(*)(omega) was computed by correcting force-indentation oscillatory data for the tip-cell contact geometry and for the hydrodynamic viscous drag. Both cell types displayed similar viscoelastic properties. The storage modulus G'(omega) increased with frequency following a power law with exponent approximately 0.2. The loss modulus G"(omega) was approximately 2/3 lower and increased similarly to G'(omega) up to approximately 10 Hz, but exhibited a steeper rise at higher frequencies. The cells showed a weak force dependence of G'(omega) and G"(omega). G(*)(omega) conformed to the power-law model with a structural damping coefficient of approximately 0.3, indicating a coupling of elastic and dissipative processes within the cell. Power-law behavior implies a continuum distribution of stress relaxation time constants. This complex dynamics is consistent with the rheology of soft glassy materials close to a glass transition, thereby suggesting that structural disorder and metastability may be fundamental features of cell architecture.     

How FMN binds to anabaena apoflavodoxin: a hydrophobic encounter at an open binding site

Molecular recognition begins when two molecules approach and establish interactions of certain strength. The mechanisms of molecular recognition reactions between biological molecules are not well known, and few systems have been analyzed in detail. We investigate here the reaction between an apoprotein and its physiological cofactor (apoflavodoxin and flavin mononucleotide) that binds reversibly to form a non-covalent complex (flavodoxin) involved in electron transfer reactions. We have analyzed the fast binding reactions between the FMN cofactor (and shorter analogs) and wild type (and nine mutant apoflavodoxins where residues interacting with FMN in the final complex have been replaced). The x-ray structures of two such mutants are reported that show the mutations are well tolerated by the protein. From the calculated microscopic binding rate constants we have performed a Phi analysis of the transition state of complex formation that indicates that the binding starts by interaction of the isoalloxazine-fused rings in FMN with residues of its hydrophobic binding site. In contrast, the phosphate in FMN, known to contribute most to the affinity of the final holoflavodoxin complex, is not bound in the transition state complex. Both the effects of ionic strength and of phosphate concentration on the wild type complex rate constant agree with this scenario. As suggested previously by nmr data, it seems that the isoalloxazine-binding site may be substantially open in solution. Interestingly, although FMN is a charged molecule, electrostatic interactions seem not to play a role in directing the binding, unlike what has been reported for other biological complexes. The binding can thus be best described as a hydrophobic encounter at an open binding site.     

Prevalence and microdiversity of Alteromonas macleodii-like microorganisms in different oceanic regions

The presence, prevalence and variability of microorganisms related to the species Alteromonas macleodii, a well known culturable gamma-Proteobacterium, has been studied in different seawater samples from diverse geographical locations, in both the Northern and Southern hemispheres, and tested with two molecular techniques (rRNA hybridization and gene cloning and sequencing). Results show that A. macleodii-like microorganisms are present in high proportions in North Atlantic and, especially, Mediterranean waters, being higher at deep samples and particle-associated fractions, in agreement with previous findings. In contrast, Southern samples (all from very cold areas near Antarctica) presented no significant hybridization signals. The analysis of the ribosomal ITS (16S-23S internal transcribed spacers) revealed that A. macleodii-like microorganisms from Mediterranean, North Atlantic, Caribbean and Red Sea waters differed in both size and sequence, mostly depending on their geographical origin, with Mediterranean and North Atlantic clones clustering into two main groups whereas Caribbean and Red Sea clones appeared separated.     

Synthesis and testing of 5-benzyl-2,4-diaminopyrimidines as potential inhibitors of leishmanial and trypanosomal dihydrofolate reductase

Dihydrofolate reductase is a drug target that has not been thoroughly investigated in leishmania and trypanosomes. Work has previously shown that 5-benzyl-2,4-diaminopyrimidines are selective inhibitors of the leishmanial and trypanosome enzymes. Modelling predicted that alkyl/aryl substitution on the 6-position of the pyrimidine ring should increase enzyme activity of 5-benzyl-2,4-diaminopyrimidines as inhibitors of leishmanial and trypanosomal dihydrofolate reductase. Various compounds were prepared and evaluated against both the recombinant enzymes and the intact organisms. The presence of a substituent had a small or negative effect on activity against the enzyme or intact parasites compared to unsubstituted compounds.