Adverse Effect of Air Pollution on Odor Perception

status: publishe

Development of an International Odor Identification Test for Children: The Universal Sniff Test

Objective: To assess olfactory function in children and to create and validate an odor identification test to diagnose olfactory dysfunction in children, which we called the Universal Sniff (U-Sniff) test.  Study design: This is a multicenter study involving 19 countries. The U-Sniff test was developed in 3 phases including 1760 children age 5-7 years. Phase 1: identification of potentially recognizable odors; phase 2: selection of odorants for the odor identification test; and phase 3: evaluation of the test and acquisition of normative data. Test—retest reliability was evaluated in a subgroup of children (n = 27), and the test was validated using children with congenital anosmia (n = 14).  Results: Twelve odors were familiar to children and, therefore, included in the U-Sniff test. Children scored a mean ± SD of 9.88 ± 1.80 points out of 12. Normative data was obtained and reported for each country. The U-Sniff test demonstrated a high test—retest reliability (r27 = 0.83, P < .001) and enabled discrimination between normosmia and children with congenital anosmia with a sensitivity of 100% and specificity of 86%.  Conclusions: The U-Sniff is a valid and reliable method of testing olfaction in children and can be used internationally

Alteraciones del olfato en la obesidad

Although the sense of smell is fundamental for the perception of food, its relationship with obesity has not been sufficiently researched. This article is a review of the literature of the relationship between olfactory function and obesity. Current evidence from animal and human studies supports the hypothesis that olfactory function is altered in obesity. Recent research indicates that individuals with obesity could have a higher sensitivity to and preference for odorant stimuli associated with energy-dense foods, and lower sensitivity to odors of foods with low caloric value and non-food odors. The study of chemosensory perception is a promising area for advancing in the understanding of the mechanisms involved in obesity.Aun cuando el sentido del olfato es fundamental para la percepción de los alimentos, su relación con la obesidad ha sido poco investigada. Este artículo es una revisión de la literatura sobre esa relación. La evidencia actual tanto en animales como en humanos apoya la hipótesis de que el olfato está alterado en esta condición. Estudios recientes señalan que los individuos obesos podrían tener una mayor sensibilidad a los olores de alimentos altos en calorías, y menor para los de bajo valor calórico incluidos los no asociados con alimentos. El estudio de la percepción quimiosensorial es un área prometedora para avanzar en el entendimiento de los mecanismos involucrados en la obesidad

Ribosome stalling and peptidyl-tRNA drop-off during translational delay at AGA codons

Minigenes encoding the peptide Met–Arg–Arg have been used to study the mechanism of toxicity of AGA codons proximal to the start codon or prior to the termination codon in bacteria. The codon sequences of the ‘mini-ORFs’ employed were initiator, combinations of AGA and CGA, and terminator. Both, AGA and CGA are low-usage Arg codons in ORFs of Escherichia coli but, whilst AGA is translated by the scarce tRNA(Arg4), CGA is recognized by the abundant tRNA(Arg2). Overexpression of minigenes harbouring AGA in the third position, next to a termination codon, was deleterious to the cell and led to the accumulation of peptidyl-tRNA(Arg4) and of the peptidyl-tRNA cognate to the preceding CGA or AGA Arg triplet. The minigenes carrying CGA in the third position were not toxic. Minigene-mediated toxicity and peptidyl-tRNA accumulation were suppressed by overproduction of tRNA(Arg4) but not by overproduction of peptidyl-tRNA hydrolase, an enzyme that is only active on substrates that have been released from the ribosome. Consistent with these findings, peptidyl-tRNA(Arg4) was identified to be mainly associated with ribosomes in a stand-by complex. These and previous results support the hypothesis that the primary mechanism of inhibition of protein synthesis by AGA triplets in pth(+) cells involves sequestration of tRNAs as peptidyl-tRNA on the stalled ribosome

Selection of Functional Quorum Sensing Systems by Lysogenic Bacteriophages in Pseudomonas aeruginosa

Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS

Selection of functional quorum sensing systems by lysogenic bacteriophages in <em>Pseudomonas aeruginosa</em>.

Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS