Whole Genome Sequence Analysis of Burkholderia contaminans FFH2055 Strain Reveals the Presence of Putative β-Lactamases

Burkholderia contaminans is a member of the Burkholderia cepacia complex (Bcc), a pathogen with increasing prevalence among cystic fibrosis (CF) patients and the cause of numerous outbreaks due to the use of contaminated commercial products. The antibiotic resistance determinants, particularly β-lactamases, have been poorly studied in this species. In this work, we explored the whole genome sequence (WGS) of a B. contaminans isolate (FFH 2055) and detected four putative β-lactamase-encoding genes. In general, these genes have more than 93% identity with β-lactamase genes found in other Bcc species. Two β-lactamases, a class A (Pen-like, suggested name PenO) and a class D (OXA-like), were further analyzed and characterized. Amino acid sequence comparison showed that Pen-like has 82% and 67% identity with B. multivorans PenA and B. pseudomallei PenI, respectively, while OXA-like displayed strong homology with class D enzymes within the Bcc, but only 22–44% identity with available structures from the OXA family. PCR reactions designed to study the presence of these two genes revealed a heterogeneous distribution among clinical and industrial B. contaminans isolates. Lastly, bla PenO gene was cloned and expressed into E. coli to investigate the antibiotic resistance profile and confers an extended-spectrum β-lactamase (ESBL) phenotype. These results provide insight into the presence of β-lactamases in B. contaminans, suggesting they play a role in antibiotic resistance of these bacteria.Fil: Degrossi, José J.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Merino, Cindy. University Fullerton; Estados UnidosFil: Isasmendi, Adela M.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Ibarra, Lorena M.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Collins, Chelsea. University Fullerton; Estados UnidosFil: Bo, Nicolás E.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Papalia, Mariana Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Fernandez, Jennifer S.. University Fullerton; Estados UnidosFil: Hernandez, Claudia M.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Papp Wallace, Krisztina M.. Case Western Reserve University; Estados UnidosFil: Bonomo, Robert A.. Case Western Reserve University; Estados UnidosFil: Vazquez, Miryam S.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Power, Pablo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Ramirez, María S.. University Fullerton; Estados Unido

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Influencia del factor sociocultural en los altos índices de adicción en los alumnos del CONALEP Alvaro Obregón 1

Licenciatura en Sociología de la Educació

A multi-scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co-culture systems

status: publishe

A multi-scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co-culture systems

Natural antimicrobials are of interest to replace traditional food decontamination methods: they are milder and maintain desirable sensory characteristics. However, efficacy can be affected by food structure/composition, thus structural effects in a co-culture pathogen/microflora system are investigated. Listeria was grown planktonically (liquid broth) or on a biphasic viscoelastic system, in monoculture with/without artificial nisin, or in co-culture with L. lactis (nisin/non-nisin producing). Microbial growth kinetics were monitored and advanced microscopy techniques were utilised to quantify cellular interactions and spatial organisation. Microstructural effects are observed on the kinetics, with differences in monoculture/co- culture. Significant microscopic differences are observed in spatial organisation and colony size. We are the first to observe changing growth location for all species in monoculture/co- culture, with differences in colony size/organisation through stationary phase. This study provides insight into the environmental stress response/adaptation of Listeria grown on structured systems in response to L. lactis and natural antimicrobials.</p

The effect of ultrasound treatment in combination with nisin on the inactivation of Listeria innocua and Escherichia coli

Ultrasound, alone or in combination with natural antimicrobials, is a novel food processing technology of interest to replace traditional food decontamination methods, as it is milder than classical sterilisation (heat treatment) and maintains desirable sensory characteristics. However, ultrasound efficacy can be affected by food structure/composition, as well as the order in which combined treatments are applied. More specifically, treatments which target different cell components could result in enhanced inactivation if applied in the appropriate order. The microbial properties i.e. Gram positive/Gram negative can also impact the treatment efficacy.This work presents a systematic study of the combined effect of ultrasound and nisin on the inactivation of the bacteria Listeria innocua (Gram positive) and Escherichia coli (Gram negative), at a range of cavitation conditions (44, 500, 1000 kHz). The order of treatment application was varied, and the impact of system structure was also investigated by varying the concentration of Xanthan gum used to create the food model systems (0 – 0.5% w/v). Microbial inactivation kinetics were monitored, and advanced microscopy and flow cytometry techniques were utilised to quantify the impact of treatment on a cellular level.Ultrasound was shown to be effective against E. coli at 500 kHz only, with L. innocua demonstrating resistance to all frequencies studied. Enhanced inactivation of E. coli was observed for the combination of nisin and ultrasound at 500 kHz, but only when nisin was applied before ultrasound treatment. The system structure negatively impacted the inactivation efficacy. The combined effect of ultrasound and nisin on E. coli was attributed to short-lived destabilisation of the outer membrane as a result of sonication, allowing nisin to penetrate the cytoplasmic membrane and facilitate cell inactivation

The impact of food model system structure on the inactivation of Listeria innocua by cold atmospheric plasma and nisin combined treatments

Novel processing methods such as cold atmospheric plasma (CAP) and natural antimicrobials like nisin, are of interest to replace traditional food decontamination approaches as, due to their mild nature, they can maintain desirable food characteristics, i.e., taste, texture, and nutritional content. However, the microbial growth characteristics (planktonic growth/surface colonies) and/or the food structure itself (liquid/solid surface) can impact the inactivation efficacy of these novel processing methods. More specifically, cells grown as colonies on a solid(like) surface experience a completely different growth environment to cells grown planktonically in liquid, and thus could display a different response to novel processing treatments through stress adaptation and/or cross protection mechanisms. The order in which combined treatments are applied could also impact their efficacy, especially if the mechanisms of action are complementary.This work presents a fundamental study on the efficacy of CAP and nisin, alone and combined, as affected by food system structure. More specifically, Listeria innocua was grown planktonically (liquid broth) or on a viscoelastic Xanthan gum gel system (1.5% w/v) and treated with CAP, nisin, or a combination of the two. Both the inactivation system, i.e., liquid versus solid(like) surface and the growth characteristics, i.e., planktonic versus colony growth, were shown to impact the treatment efficacy. The combination of nisin and CAP was more effective than individual treatments, but only when nisin was applied before the CAP treatment.This study provides insight into the environmental stress response/adaptation of L. innocua grown on structured systems in response to natural antimicrobials and novel processing technologies, and is a step towards the faster delivery of these food decontamination methods from the bench to the food industry

Cuba 1989-2010, Modelo de Robert Dahl

En el presente trabajo se hace un breve análisis de la situación política, económica y social de la República de Cuba, tomando como base teórica el modelo de Robert Dahl. Con ello se pretende demostrar el camino de inclusión o liberalización que el país ha tomado entre los años de 1989 a 2010. La recopilación de datos históricos indica que Cuba ha estado en una hegemonía cerrada. Luego de la investigación es preciso valorar que para 2010 la República de Cuba ha avanzado hacia la inclusión, pero sigue limitando por completo a la oposición pública, con derechos al voto solamente para legitimar el régimen socialista que se encuentra hasta la actualidad

Draft Genome Sequence of Empedobacter falsenii comb. nov. (ex- Wautersiella falsenii) Wf282, a strain isolated from a cervical neck abscess

Wautersiella falsenii was first described in the year 2006 by Kampfer et al. (1). This genus phenotypically resembles members of the genera Chryseobacterium and Empedobacter. W. falsenii is a non-motile, gram-negative rod that grows aerobically at 20, 30 and 37 °C on standard media such as tryptic soy agar or blood agar. The Wf282 genome sequence could lead us to clarify the role and importance of this particular species as a nosocomial pathogen and permit us to compare the genome content of this species with its close relatives to identify defined features of E. falsenii.Fil: Traglia, German Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones En Microbiología y Parasitología Médica; ArgentinaFil: Dixon, Chelsea. California State University; Estados UnidosFil: Chiem, Kevin. California State University; Estados UnidosFil: Almuzara, Marisa. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Barberis, Claudia. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Montaña, Sabrina Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones En Microbiología y Parasitología Médica; ArgentinaFil: Merino, Cindy. California State University; Estados UnidosFil: Mussi, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Centro de Estudios Fotosintéticos y Bioquímicos (i); ArgentinaFil: Tolmasky, Marcelo E.. California State University; Estados UnidosFil: Iriarte, Andrés. Instituto de Invest. Biologicas "clemente Estable"; Uruguay. Universidad de la Republica; UruguayFil: Vay, Carlos. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Ramirez, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones En Microbiología y Parasitología Médica; Argentina. California State University; Estados Unido