Structural Determinants of the Specific Activities of an L-Amino Acid Oxidase from Pseudoalteromonas luteoviolacea CPMOR-1 with Broad Substrate Specificity.

The Pseudoalteromonas luteoviolacea strain CPMOR-1 expresses a flavin adenine dinucleotide (FAD)-dependent L-amino acid oxidase (LAAO) with broad substrate specificity. Steady-state kinetic analysis of its reactivity towards the 20 proteinogenic amino acids showed some activity to all except proline. The relative specific activity for amino acid substrates was not correlated only with Km or kcat values, since the two parameters often varied independently of each other. Variation in Km was attributed to the differential binding affinity. Variation in kcat was attributed to differential positioning of the bound substrate relative to FAD that decreased the reaction rate. A structural model of this LAAO was compared with structures of other FAD-dependent LAAOs that have different substrate specificities: an LAAO from snake venom that prefers aromatic amino acid substrates and a fungal LAAO that is specific for lysine. While the amino acid sequences of these LAAOs are not very similar, their overall structures are comparable. The differential activity towards specific amino acids was correlated with specific residues in the active sites of these LAAOs. Residues in the active site that interact with the amino and carboxyl groups attached to the α-carbon of the substrate amino acid are conserved in all of the LAAOs. Residues that interact with the side chains of the amino acid substrates show variation. This provides insight into the structural determinants of the LAAOs that dictate their different substrate preferences. These results are of interest for harnessing these enzymes for possible applications in biotechnology, such as deracemization.

Structure and Enzymatic Properties of an Unusual Cysteine Tryptophylquinone-Dependent Glycine Oxidase from Pseudoalteromonas luteoviolacea.

Glycine oxidase from Pseudoalteromonas luteoviolacea (PlGoxA) is a cysteine tryptophylquinone (CTQ)-dependent enzyme. Sequence analysis and phylogenetic analysis place it in a newly designated subgroup (group IID) of a recently identified family of LodA-like proteins, which are predicted to possess CTQ. The crystal structure of PlGoxA reveals that it is a homotetramer. It possesses an N-terminal domain with no close structural homologues in the Protein Data Bank. The active site is quite small because of intersubunit interactions, which may account for the observed cooperativy toward glycine. Steady-state kinetic analysis yielded the following values: kcat = 6.0 ± 0.2 s-1, K0.5 = 187 ± 18 µM, and h = 1.77 ± 0.27. In contrast to other quinoprotein amine dehydrogenases and oxidases that exhibit anomalously large primary kinetic isotope effects on the rate of reduction of the quinone cofactor by the amine substrate, no significant primary kinetic isotope effect was observed for this reaction of PlGoxA. The absorbance spectrum of glycine-reduced PlGoxA exhibits features in the range of 400-650 nm that have not previously been seen in other quinoproteins. Thus, in addition to the unusual structural features of PlGoxA, the kinetic and chemical reaction mechanisms of the reductive half-reaction of PlGoxA appear to be distinct from those of other amine dehydrogenases and amine oxidases that use tryptophylquinone and tyrosylquinone cofactors.

The Pseudoalteromonas luteoviolacea L-amino Acid Oxidase with Antimicrobial Activity Is a Flavoenzyme.

The marine environment is a rich source of antimicrobial compounds with promising pharmaceutical and biotechnological applications. The Pseudoalteromonas genus harbors one of the highest proportions of bacterial species producing antimicrobial molecules. For decades, the presence of proteins with L-amino acid oxidase (LAAO) and antimicrobial activity in Pseudoalteromonas luteoviolacea has been known. Here, we present for the first time the identification, cloning, characterization and phylogenetic analysis of Pl-LAAO, the enzyme responsible for both LAAO and antimicrobial activity in P. luteoviolacea strain CPMOR-2. Pl-LAAO is a flavoprotein of a broad substrate range, in which the hydrogen peroxide generated in the LAAO reaction is responsible for the antimicrobial activity. So far, no protein with a sequence similarity to Pl-LAAO has been cloned or characterized, with this being the first report on a flavin adenine dinucleotide (FAD)-containing LAAO with antimicrobial activity from a marine microorganism. Our results revealed that 20.4% of the sequenced Pseudoalteromonas strains (specifically, 66.6% of P. luteoviolacea strains) contain Pl-laao similar genes, which constitutes a well-defined phylogenetic group. In summary, this work provides insights into the biological significance of antimicrobial LAAOs in the Pseudoalteromonas genus and shows an effective approach for the detection of novel LAAOs, whose study may be useful for biotechnological applications.

Permanent and decidua dentition as chronological biomarkers of heavy metal contamination: A review of the forensic literature.

STATEMENT OF PROBLEM: Contamination with heavy metals (HM) has great environmental consequences in the environment due to lack of biodegradation, in addition, accumulation in living beings causes defects in tissues and organs, deteriorating their function and inducing a wide spectrum of diseases. Human biomonitoring consists of the periodic measurement of a certain chemical substance or metabolite in a particular population, using matrices that can be acute or chronic. Teeth are chronic matrices that have great characteristics of resistance and chronological storage of information. This review aims to identify the mechanisms, spatial location, and affinity of HM within teeth, along with understanding its applicability as a chronological record matrix in the face of HM contamination. MATERIAL AND METHODS: A systematic search review was performed using the PubMed/Medline, Web of Science, and Scopus metasearch engines, and the terms "teeth" OR "dental" OR "tooth" AND "heavy metals" were intersected. Complete articles are included in Spanish, English and Portuguese without time restrictions, involving studies in humans or in vitro; Letters to the editor, editorials and those that did not refer to information on the incorporation and relationship of HM with the teeth were excluded. RESULTS: 837 published articles were detected, 91 were adjusted to the search objective, and 6 were manually included. Teeth are structures with a great capacity for information retention in the face of HM contamination due to low physiological turnover and their long processes of marked formations by developmental biorhythm milestones such as the neonatal line (temporal reference indicator). The contamination mechanisms inside the tooth are linked to the affinity of hydroxyapatite for HM; this incorporation can be in the soft matrix during the apposition phase or as part of the chemical exchanges between hydroxyapatite and the elements of the environment. CONCLUSION: The teeth present unique characteristics of great resistance and affinity for HM, as well as a chronological biomarker for human biomonitoring, so they can be used as means of expertise or evidence to confirm or rule out a fact of environmental characteristics in the legal field.

Cross-Talking of Pathway-Specific Regulators in Glycopeptide Antibiotics (Teicoplanin and A40926) Production.

Teicoplanin and A40926 (natural precursor of dalbavancin) are clinically relevant glycopeptide antibiotics (GPAs) produced by Actinoplanes teichomyceticus NRRL B-16726 and Nonomuraea gerenzanensis ATCC 39727. Their biosynthetic enzymes are coded within large biosynthetic gene clusters (BGCs), named tei for teicoplanin and dbv for A40926, whose expression is strictly regulated by pathway-specific transcriptional regulators (PSRs), coded by cluster-situated regulatory genes (CSRGs). Herein, we investigated the "cross-talk" between the CSRGs from tei and dbv, through the analysis of GPA production levels in A. teichomyceticus and N. gerenzanensis strains, with knockouts of CSRGs cross-complemented by the expression of heterologous CSRGs. We demonstrated that Tei15* and Dbv4 StrR-like PSRs, although orthologous, were not completely interchangeable: tei15* and dbv4 were only partially able or unable to cross-complement N. gerenzanensis knocked out in dbv4 and A. teichomyceticus knocked out in tei15*, implying that the DNA-binding properties of these PSRs are more different in vivo than it was believed before. At the same time, the unrelated LuxR-like PSRs Tei16* and Dbv3 were able to cross-complement corresponding N. gerenzanensis knocked out in dbv3 and A. teichomyceticus knocked out in tei16*. Moreover, the heterologous expression of dbv3 in A. teichomyceticus led to a significant increase in teicoplanin production. Although the molecular background of these events merits further investigations, our results contribute to a deeper understanding of GPA biosynthesis regulation and offer novel biotechnological tools to improve their production.

Genomic Insights into the Distribution and Phylogeny of Glycopeptide Resistance Determinants within the Actinobacteria Phylum.

The spread of antimicrobial resistance (AMR) creates a challenge for global health security, rendering many previously successful classes of antibiotics useless. Unfortunately, this also includes glycopeptide antibiotics (GPAs), such as vancomycin and teicoplanin, which are currently being considered last-resort drugs. Emerging resistance towards GPAs risks limiting the clinical use of this class of antibiotics-our ultimate line of defense against multidrug-resistant (MDR) Gram-positive pathogens. But where does this resistance come from? It is widely recognized that the GPA resistance determinants-van genes-might have originated from GPA producers, such as soil-dwelling Gram-positive actinobacteria, that use them for self-protection. In the current work, we present a comprehensive bioinformatics study on the distribution and phylogeny of GPA resistance determinants within the Actinobacteria phylum. Interestingly, van-like genes (vlgs) were found distributed in different arrangements not only among GPA-producing actinobacteria but also in the non-producers: more than 10% of the screened actinobacterial genomes contained one or multiple vlgs, while less than 1% encoded for a biosynthetic gene cluster (BGC). By phylogenetic reconstructions, our results highlight the co-evolution of the different vlgs, indicating that the most diffused are the ones coding for putative VanY carboxypeptidases, which can be found alone in the genomes or associated with a vanS/R regulatory pair.

Skin manifestations in pediatric patients with primary immunodeficiency diseases (PIDs) in a tertiary care hospital in Colombia.

BACKGROUND: The current literature describes the characteristics of some skin manifestations in the context of primary immunodeficiency diseases (PIDs), also known as inborn errors of the immune system. However, there are hardly any data on the epidemiological trends of skin manifestations and PIDs in Latin America (LA). We aimed to describe the characteristics of patients with skin manifestations and the diagnosis of a PID treated at a tertiary hospital in Colombia. METHODS: This was a retrospective observational study. Data were taken from the institutional database of pediatric PIDs, which includes 306 patients under 18 years of age who attended a tertiary care center in Cali, Colombia for inpatient or outpatient services between December 2013 and December 2018. A trained third-year dermatology resident reviewed the electronic clinical records of all the patients in the database and double-checked patients who presented with cutaneous signs and symptoms. RESULTS: A total of 83 patients out of the original 306 patients (27.1%) presented with some type of cutaneous manifestation. Of these patients, 56.6% had atopic dermatitis, 56.6% reported at least one episode of skin infection, and some of the patients had both of these manifestations. Infections were more frequent in the PID group of combined immunodeficiency associated with well-defined syndromes and atopic dermatitis in the group of antibody deficiencies. CONCLUSIONS: It is important to recognize dermatological clinical characteristics in patients with PIDs. More studies are necessary to establish recommendations regarding the approach of diagnosis and management of these patients.

Genomic-Led Discovery of a Novel Glycopeptide Antibiotic by Nonomuraea coxensis DSM 45129.

Glycopeptide antibiotics (GPAs) are last defense line drugs against multidrug-resistant Gram-positive pathogens. Natural GPAs teicoplanin and vancomycin, as well as semisynthetic oritavancin, telavancin, and dalbavancin, are currently approved for clinical use. Although these antibiotics remain efficient, emergence of novel GPA-resistant pathogens is a question of time. Therefore, it is important to investigate the natural variety of GPAs coming from so-called "rare" actinobacteria. Herein we describe a novel GPA producer-Nonomuraea coxensis DSM 45129. Its de novo sequenced and completely assembled genome harbors a biosynthetic gene cluster (BGC) similar to the dbv BGC of A40926, the natural precursor to dalbavancin. The strain produces a novel GPA, which we propose is an A40926 analogue lacking the carboxyl group on the N-acylglucosamine moiety. This structural difference correlates with the absence of dbv29-coding for an enzyme responsible for the oxidation of the N-acylglucosamine moiety. Introduction of dbv29 into N. coxensis led to A40926 production in this strain. Finally, we successfully applied dbv3 and dbv4 heterologous transcriptional regulators to trigger and improve A50926 production in N. coxensis, making them prospective tools for screening other Nonomuraea spp. for GPA production. Our work highlights genus Nonomuraea as a still untapped source of novel GPAs.

New Molecular Tools for Regulation and Improvement of A40926 Glycopeptide Antibiotic Production in Nonomuraea gerenzanensis ATCC 39727.

Genome sequencing has revealed that Nonomuraea spp. represent a still largely unexplored source of specialized metabolites. Nonomuraea gerenzanensis ATCC 39727 is the most studied representative species since it produces the glycopeptide antibiotic (GPA) A40926 - the precursor of the clinically relevant antibiotic dalbavancin, approved by the FDA in 2014 for the treatment of acute skin infections caused by multi-drug resistant Gram-positive pathogens. The clinical relevance of dalbavancin has prompted increased attention on A40926 biosynthesis and its regulation. In this paper, we investigated how to enhance the genetic toolkit for members of the Nonomuraea genus, which have proved quite recalcitrant to genetic manipulation. By constructing promoter-probe vectors, we tested the activity of 11 promoters (heterologous and native) using the GusA reporter system in N. gerenzanensis and in Nonomuraea coxensis; this latter species is phylogenetically distant from N. gerenzanesis and also possesses the genetic potential to produce A40926 or a very similar GPA. Finally, the strongest constitutive promoter analyzed in this study, aac(3)IVp, was used to overexpress the cluster-situated regulatory genes controlling A40926 biosynthesis (dbv3 and dbv4 from N. gerenzanensis and nocRI from N. coxensis) in N. gerenzanensis, and the growth and productivity of the best performing strains were assessed at bioreactor scale using an industrial production medium. Overexpression of positive pathway-specific regulatory genes resulted in a significant increase in the level of A40926 production in N. gerenzanensis, providing a new knowledge-based approach to strain improvement for this valuable glycopeptide antibiotic.

Novel ATP7A gene mutation in a patient with Menkes disease.

BACKGROUND: Menkes disease is a congenital neurodegenerative disorder caused by ATP7A gene mutations. Clinical features include epilepsy, growth delay, reduced muscle strength, skin laxity, abnormal hair, and urologic abnormalities. CASE PRESENTATION: We describe an infant with developmental delay, neurologic degeneration, and kinky hair. Molecular test revealed a novel heterozygous mutation in exon 21 of the ATP7A gene. The genotype and phenotype of the patient were compared with those of the patients reported in the literature. CONCLUSION: We propose that this mutation caused a dysfunctional protein resulting in classical Menkes disease. This case adds to the spectrum of pathogenic variants of the ATP7A gene known to cause disease.

[Impact of a UV education program on the knowledge and behavior in elementary school children]. / Impacto de un programa de foto-educación en los conocimientos y hábitos de una población escolar.

INTRODUCTION: Colombians are exposed year round to high doses of ultraviolet radiation. Although no reliable epidemiological data are available for the incidence of skin cancer, it is a frequent pathology not limited to advanced age classes. OBJECTIVE: The current study was done at elementary schools in Cali in zones categorized at socioeconomic levels 1 to 4 to evaluate the impact of a photo-education program for its effect on the knowledge and behavior of a group of elementary school children. MATERIALS AND METHODS: Five hundred forty-seven children from kindergarten to grade three were evaluated in 4 schools categorized in socioeconomic levels 1 to 4. The students were interviewed to evaluate their knowledge and behavior with regard to effects of UV exposure. One school rated at level 1-2 and one school at level 3-4 received education on UV protection. Other two schools, rated at levels 1-2 and 3-4 each received no education on UV protection. The questionnaire was repeated in the 4 schools, and a statistical analysis was done to evaluate the impact the education program had on educated and control groups. RESULTS: The children that received the education program showed statistically significant improvement in behavior and knowledge. The education was more effective in low socioeconomic level populations. CONCLUSIONS: Follow-up studies are required to evaluate how knowledge persists over time. The need of a public health campaign to educate children in skin cancer prevention is evident.

Etanercept-induced pityriasis lichenoides chronica in a patient with rheumatoid arthritis.

We present a 74-year-old female patient who developed a pityriasis lichenoides chronica (PLC) during etanercept therapy. This association is not described in the literature and might be considered in the spectrum of cutaneous adverse reactions of etanercept.

Intervención educativa sobre salud bucal en estudiantes de la escuela primaria Rodney Coutin Correa / Educational intervention concerning oral health in students of the primary school Rodney Coutin Correa

Se realizó un estudio de intervención grupal educativa, denominada "Por una blanca sonrisa", para modificar conocimientos y cambiar actitudes negativas acerca de la salud bucal en adolescentes de sexto grado de la escuela primaria urbana "Rodney Coutin Correa" de Baracoa, en el período comprendido de diciembre a marzo 2017. La muestra estuvo integrada por 40 estudiantes, con los cuales se realizaron actividades educativas consistentes en técnicas participativas y juegos didácticos. A cada educando se le aplicó un cuestionario sobre los temas tratados. Se obtuvo que muchos de los niños no tuvieran información suficiente sobre higiene bucal, placa dental y enfermedades bucales. La acción desarrollada modificó positivamente los conocimientos inadecuados hasta alcanzar la categoría de adecuados en su mayoría(AU)

A study of educational group intervention was made, denominated "For a white smile", to modify knowledge and to change negative attitudes about oral health in adolescents of sixth grade of the urban primary school "Rodney Coutin Correa" of Baracoa, in the covered period of December to March 2017. The sample was integrated by 40 students, which were carried out in educational activities, participation techniques and didactic games. To each pupil was applied a questionnaire on the treated topics. It was obtained that many of the children didn't have enough information on oral hygiene, dental plaque and oral illnesses. The developed action modified the inadequate knowledge positively until reaching the category of having adequate in its majority(AU)

Impacto de un programa de foto-educación en los conocimientos y hábitos de una población escolar / Impact of a UV education program on the knowledge and behavior in elementary school children

Introducción. Colombia está expuesta todo el año a altos índices de radiación ultravioleta. Aunque aún no se cuenta con estadísticas precisas del cáncer cutáneo, se sabe que este problema es una causa frecuente de consulta, presentándose cada día en personas más jóvenes. Por esta razón, se realizó un trabajo de foto-educación en colegios de estrato socioeconómico 1 a 4 en Cali. Objetivo. Determinar el impacto de la foto-educación en los conocimientos y prácticas de fotoprotección en una población escolar. Materiales y métodos. Se estudiaron 547 niños de kinder hasta tercero de primaria provenientes de cuatro colegios de estratos 1 a 4. Se evaluaron los conocimientos y hábitos en el tema mediante una encuesta. Un colegio estrato 1-2 y otro de estrato 3-4 recibieron el programa de foto-educación. Los dos colegios restantes, uno estrato 1-2 y otro estrato 3-4 fueron los controles no intervenidos. Posteriormente, se aplicó la misma encuesta en los cuatro colegios y se realizó el análisis estadístico para evaluar el impacto de la foto-educación, comparando los intervenidos con los no intervenidos. Resultados. Se evidenció un cambio estadísticamente significativo en los conocimientos y hábitos adecuados a favor de los colegios intervenidos. La foto-educación fue más efectiva en los estratos socioeconómicos más bajos. Discusión. Se demostró cómo con un programa sencillo se logró brindar foto-educación a niños de estratos 1 a 4, y cómo los estratos más bajos demostraron ser los más susceptibles de mejorar. Conclusiones. Se requiere un seguimiento en el tiempo para evaluar la duración de los conocimientos y convertir este tipo de programas en campañas continuas y generalizadas, preferentemente como parte del pensum escolar