Amphibian skin is a rich source of natural compounds with diverse antimicrobial and immune defense properties. Our previous studies showed that the frog skin secretions obtained by skin micro-organs from various species of Colombian anurans have antimicrobial activities against bacteria and viruses. We purified for the first time two antimicrobial peptides from the skin micro-organs of the Orinoco lime treefrog (Sphaenorhynchus lacteus) that correspond to Buforin II (BF2) and Frenatin 2.3S (F2.3S). Here, we have synthesized the two peptides and tested them against Gram-negative and Gram-positive bacteria, observing an effective bactericidal activity at micromolar concentrations. Evaluation of BF2 and F2.3S membrane destabilization activity on bacterial cell cultures and synthetic lipid bilayers reveals a distinct membrane interaction mechanism. BF2 agglutinates E. coli cells and synthetic vesicles, whereas F2.3S shows a high depolarization and membrane destabilization activities. Interestingly, we found that F2.3S is able to internalize within bacterial cells and can bind nucleic acids, as previously reported for BF2. Moreover, bacterial exposure to both peptides alters the expression profile of genes related to stress and resistance response. Overall, these results show the multifaceted mechanism of action of both antimicrobial peptides that can provide alternative tools in the fight against bacterial resistance.

Objetivo Caracterizar la forma en que los agricultores se exponen a los plaguicidas y se presenta la intoxicación.Materiales y Métodos Estudio multi-métodos multinivel (individuo y comunidad), que incluyó métodos etnográficos, encuesta y medición de plaguicidas en agua y muestras humanas.Resultados Se describió el proceso productivo y se conocieron los principales factores de riesgo. Los plaguicidas son considerados el mayor peligro en el trabajo y en sus viviendas. Los trabajadores tienen precarias condiciones laborales y no están protegidos por el sistema de riesgos laborales. En las muestras de agua se encontraron azinfos-metil, endosulfán, b-BHC, bromofos-metil, bromofos-etil y 2,4-DDT. En la encuesta participaron 381 trabajadores de los cuales 12.86, 67.98 y 5.51 % tuvieron intoxicaciones leves, moderadas y severas, respectivamente. Los casos severos tenían menores niveles de escolaridad, menor nivel de afiliación al régimen contributivo del sistema de seguridad social y un mayor número tenía enfermedad cardiovascular, diabetes, herpes u otras infecciones virales.Conclusión Existen precarias condiciones laborales que favorecen la exposición a plaguicidas caracterizadas por la exclusión del sistema de riesgos laborales, pobreza y baja educación. Es urgente la inclusión de estos trabajadores al sistema de riesgos laborales y la mejora de las condiciones de vida. De esa manera se podrán disminuir las prácticas inseguras en el manejo de plaguicidas.

Investigating the degree of exposure to organic solvents and related genotoxic consequences in paint-factory workers by using cytogenetic monitoring and determining micronuclei frequency in lymphocytes and DNA damage as assessed by comet assays. Excretion of phenol and hippuric and methylhippuric acids in urine was investigated as biomarkers for benzene, toluene and xylene exposure. Urine samples were taken in two paint-factories in Bogotá and in a non-exposed control group. Benzene, toluene and xylene concentrations in air were measured in the work setting. Micronuclei and simple DNA chain breakage frequency were evaluated in peripheral blood sample mononuclear cells to assess early genetic effects. Hippuric acid concentration was found to be within normal values; by contrast, phenol and methylhippuric acid sample concentrations were above normal values by 3,3 % and 50,8 %, respectively. Benzene concentration in air was above permissible limits in one of the factories. There were no statistical differences regarding genetic biomarkers between exposed and non-exposed workers. Organic solvent levels in the samples were apparently low, which is consistent with the absence of genotoxicity in cells. This study represents a step forward in research in occupational health surveillance.

Inherited bleeding disorders (IBDs) are the most frequent congenital diseases in the Colombian population; three of them are hemophilia A (HA), hemophilia B (HB), and von Willebrand Disease (VWD). Currently, diagnosis relies on multiple clinical laboratory assays to assign a phenotype. Due to the lack of accessibility to these tests, patients can receive an incomplete diagnosis. In these cases, genetic studies reinforce the clinical diagnosis. The present study characterized the molecular genetic basis of 11 HA, three HB, and five VWD patients by sequencing the F8, F9, or the VWF gene. Twelve variations were found in HA patients, four in HB patients, and 19 in WVD patients. From these variations a total of 25 novel variations were found. Disease-causing variations were used as positive controls for validation of the high-resolution melting (HRM) variant-scanning technique. This approach is a low-cost genetic diagnostic method proposed to be incorporated in developing countries. For the data analysis, we developed an accessible open-source code in Python that improves HRM data analysis with better sensitivity of 95% and without bias when using different HRM equipment and software. Analysis of amplicons with a length greater than 300 bp can be performed by implementing an analysis by denaturation domains.

Background: It is well known the adverse effect of mercury exposure on pregnant women and newborns. Interactions between environmental factors and individual genetic susceptibility have been identified, particularly polymorphisms of codifying genes for the Glutathione S-transferase family (GSTs). Herein, we report a case series of patients with high Hg levels in biosamples. Case Series: Fourteen cases with high Hg levels were identified. Non-occupational or home exposure risk factors were identified. All mothers reported fish consumption during pregnancy. Almost 60% of the individuals were null for either one GSTs gene. To date, in the subsequent mother-child pairs toxicology controls no signs or symptoms of poisoning were identified and most of the mercury levels decreased and are below the accepted limit. Discussion: In this case series we found some similarities with the literature; among them, the relation of Hg ratio in maternal blood and umbilical cord, a possible exposure factor is the consumption of fish during pregnancy and, the high levels of Hg may be related with susceptibility biomarkers such as GSTs gene polymorphisms. This case series highlights the need to develop studies that evaluate the interactions between environmental factors and individual genetic susceptibility. Additionally, the importance of evaluating which Colombian fish species present the highest levels of Hg.