ISPst9, an ISL3-like insertion sequence from Pseudomonas stutzeri AN10 involved in catabolic gene inactivation

A novel insertion sequence (IS), ISPst9, from Pseudomonas stutzeri AN10 was cloned and characterized. ISPst9 is a typical bacterial IS, consisting of a 2472-bp element flanked by 24-bp perfect inverted repeats that generates 8-bp AT-rich target duplications upon insertion. The sequence also contains a gene that encodes an active transposase (TnpA) with significant amino acid identity to members of the ISL3 family. Southern blot analysis of digested genomic DNA of strain AN 10 and its 4-chlorosalicylate-degrading derivative strain AN142 demonstrated that native ISPst9 transposes in multiple copies, with one of them responsible for the nahH insertional inactivation observed in strain AN142. Precise excision of ISPst9 yielded NahH+ revertants of AN142 at high frequencies (up to 10-6). In vivo transposition, mainly in multiple copies, of an ISPst9 derivative containing a KmR cassette cloned into a suicide vector was also demonstrated. Hybridization experiments carried out with different strains of P. stutzeri and with 292 phylogenetically distinct environmental isolates suggested that the presence of an ISPst9-like IS occurs in diverse bacteria together with the presence of aromatic hydrocarbon-degrading determinants (Journal)Funds were obtained from projects VEM2003-20565 and CTM2005-01783 from MEC, and project PRIB2004-10152 from CAIBPeer Reviewe

IS Pst9, an ISL3-like insertion sequence from Pseudomonas stutzeri AN10 involved in catabolic gene inactivation

A novel insertion sequence (IS), ISPst9, from Pseudomonas stutzeri AN10 was cloned and characterized. ISPst9 is a typical bacterial IS, consisting of a 2472-bp element flanked by 24-bp perfect inverted repeats that generates 8-bp AT-rich target duplications upon insertion. The sequence also contains a gene that encodes an active transposase (TnpA) with significant amino acid identity to members of the ISL3 family. Southern blot analysis of digested genomic DNA of strain AN10 and its 4-chlorosalicylate-degrading derivative strain AN142 demonstrated that native ISPst9 transposes in multiple copies, with one of them responsible for the nahH insertional inactivation observed in strain AN142. Precise excision of ISPst9 yielded NahH+ revertants of AN142 at high frequencies (up to 10-6). In vivo transposition, mainly in multiple copies, of an ISPst9 derivative containing a KmR cassette cloned into a suicide vector was also demonstrated. Hybridization experiments carried out with different strains of P. stutzeri and with 292 phylogenetically distinct environmental isolates suggested that the presence of an ISPst9-like IS occurs in diverse bacteria together with the presence of aromatic hydrocarbon-degrading determinants

Los trabajadores temporarios de la agricultura frente al COVID-19

La agricultura y sus trabajadores y trabajadoras conforman un ámbito de particular complejidad para la elaboración, implementación y supervisión de acciones para contener y eventualmente mitigar los efectos de la pandemia.Las condiciones laborales y sociales que afectan a una mayoría de hogares que habitan en las áreas rurales y a los trabajadores agrícolas en particular, los convierten en grupos más expuestos a la enfermedad y también con mayores restricciones para enfrentarla por limitaciones de acceso a los servicios en general y de la salud en particular.El carácter atípico del trabajo agrario por el predominio de ocupaciones temporarias en condiciones de informalidad laboral y/o vulnerabilidad social colocan a la problemática del COVID-19 en un contexto específico para el diseño de políticas laborales y sociales.La cadena productiva del limón en la provincia de Tucumán al que hace referencia este Informe caracterizada por una fuerte articulación a los mercados mundiales y con presencia mayoritaria de trabajadores y trabajadoras de temporada en tareas de cosecha, empaque e industria, se constituye en un escenario de significación para analizar las acciones desplegadas y sus problemas y limitaciones en el marco de la pandemia.La elaboración de protocolos para organizar la producción y el trabajo muestra que son un instrumento necesario en tanto establecen condiciones básicas para el desarrollo de la actividad, pero que requieren ser actualizados continuamente y complementados con otras acciones.Fil: Albertí, Alfonsina Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Bageneta, Jose Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Bardomas, Silvia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Bober, Gabriel Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Lombardi, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Mercado Mott, Macarena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Neiman, Guillermo Saul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Ramos Berrondo, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; ArgentinaFil: Scirica, Sebastián Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentin

The Antimicrobials Anacardic Acid and Curcumin Are Not-Competitive Inhibitors of Gram-Positive Bacterial Pathogenic Glyceraldehyde-3-Phosphate Dehydrogenase by a Mechanism Unrelated to Human C5a Anaphylatoxin Binding

The ubiquitous and highly abundant glycolytic enzyme D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is pivotal for the energy and carbon metabolism of most organisms, including human pathogenic bacteria. For bacteria that depend mostly on glycolysis for survival, GAPDH is an attractive target for inhibitor discovery. The availability of high-resolution structures of GAPDH from various pathogenic bacteria is central to the discovery of new antibacterial compounds. We have determined the X-ray crystal structures of two new GAPDH enzymes from Gram-positive bacterial pathogens, Streptococcus pyogenes and Clostridium perfringens. These two structures, and the recent structure of Atopobium vaginae GAPDH, reveal details in the active site that can be exploited for the design of novel inhibitors based on naturally occurring molecules. Two such molecules, anacardic acid and curcumin, have been found to counter bacterial infection in clinical settings, although the cellular targets responsible for their antimicrobial properties remain unknown. We show that both anacardic acid and curcumin inhibit GAPDH from two bacterial pathogens through uncompetitive and non-competitive mechanisms, suggesting GAPDH as a relevant pharmaceutical target for antibacterial development. Inhibition of GAPDH by anacardic acid and curcumin seems to be unrelated to the immune evasion function of pathogenic bacterial GAPDH, since neither natural compound interfere with binding to the human C5a anaphylatoxin

ISPst9, an ISL3-like insertion sequence from Pseudomonas stutzeri AN10 involved in catabolic gene inactivation

A novel insertion sequence (IS), ISPst9, from Pseudomonas stutzeri AN10 was cloned and characterized. ISPst9 is a typical bacterial IS, consisting of a 2472-bp element flanked by 24-bp perfect inverted repeats that generates 8-bp AT-rich target duplications upon insertion. The sequence also contains a gene that encodes an active transposase (TnpA) with significant amino acid identity to members of the ISL3 family. Southern blot analysis of digested genomic DNA of strain AN 10 and its 4-chlorosalicylate-degrading derivative strain AN142 demonstrated that native ISPst9 transposes in multiple copies, with one of them responsible for the nahH insertional inactivation observed in strain AN142. Precise excision of ISPst9 yielded NahH+ revertants of AN142 at high frequencies (up to 10-6). In vivo transposition, mainly in multiple copies, of an ISPst9 derivative containing a KmR cassette cloned into a suicide vector was also demonstrated. Hybridization experiments carried out with different strains of P. stutzeri and with 292 phylogenetically distinct environmental isolates suggested that the presence of an ISPst9-like IS occurs in diverse bacteria together with the presence of aromatic hydrocarbon-degrading determinants (Journal

Prevalence and Control of <i>Pseudomonas aeruginosa</i> in Tourist Facilities across the Canary Islands, Spain

Pseudomonas aeruginosa is a common pathogen associated with recreational water facilities and poses risks to public health. However, data on the prevalence of P. aeruginosa in tourist destinations like the Canary Islands, Spain, remain limited. We assessed P. aeruginosa prevalence in 23 tourist facilities from 2016 to 2019. Compliance with water quality standards was evaluated, and 3962 samples were collected and analyzed. We examined different types of recreational water installations, including outer swimming pools, whirlpools, and cold wells. Of the sampled facilities, 31.2% did not comply with the current legislation’s parametric values, mainly due to inadequate disinfectant levels, water temperature, and P. aeruginosa presence. The prevalence of P. aeruginosa was 4.8%, comparable to some European countries but lower than others. Cold wells displayed the highest non-compliance rate (89.2%) and yet exhibited a lower P. aeruginosa prevalence (1.9%) than outer swimming pools and whirlpools. Children’s presence did not significantly impact P. aeruginosa contamination. Chlorine-based disinfectants are more effective than bromine-based ones in controlling P. aeruginosa. Regional variability in contamination was observed, with Fuerteventura showing lower colonization rates. Disinfectant levels play a critical role in P. aeruginosa control, and maintaining adequate levels is essential, particularly in bromine-treated installations. Our findings provide valuable insights into the prevalence and distribution of P. aeruginosa in recreational waters within tourist facilities. Tailored strategies are needed to ensure water safety in different Spanish regions. Continued monitoring and assessment, combined with artificial intelligence and machine learning, will enable the implementation of targeted interventions to protect the health of recreational water users

Role of Lung Epithelial Cells in Defense against Klebsiella pneumoniae Pneumonia

The airway epithelium represents a primary site for the entry of pathogenic bacteria into the lungs. It has been suggested for many respiratory pathogens, including Klebsiella pneumoniae, that adhesion and invasion of the lung epithelial cells is an early stage of the pneumonia process. We observed that poorly encapsulated K. pneumoniae clinical isolates and an isogenic unencapsulated mutant invaded lung epithelial cells more efficiently than highly encapsulated strains independent of the K type. By contrast, the unencapsulated mutant was completely avirulent in a mouse model of pneumonia, unlike the wild-type strain, which produced pneumonia and systemic infection. Furthermore, the unencapsulated mutant bound more epithelially produced complement component C3 than the wild-type strain. Our results show that lung epithelial cells play a key role as a host defense mechanism against K. pneumoniae pneumonia, using two different strategies: (i) ingestion and control of the microorganisms and (ii) opsonization of the microorganisms. Capsular polysaccharide avoids both mechanisms and enhances the virulence of K. pneumoniae

Role of the htrA Gene in Klebsiella pneumoniae Virulence

We recently described the use of mini-Tn5 to generate complement-sensitive mutants derived from a complement-resistant Klebsiella pneumoniae clinical isolate deficient in the lipopolysaccharide O side chain. One mutant with a reduced capacity to survive in nonimmune human sera carried the transposon inserted in the htrA gene. We cloned and sequenced the gene and predicted from the deduced amino acid sequence that the putative HtrA homolog contains structural features similar to those of previously described HtrA proteins. To investigate the biological functions and the role of the htrA gene in the virulence of K. pneumoniae, we constructed an isogenic mutant by insertion-duplication mutagenesis. Characterization of the mutant showed that it had greater sensitivity to temperature (50°C) and oxidative stress (H(2)O(2)) than the parent strain. Furthermore, the htrA mutant produced less capsule, bound more molecules of complement component C3, and was more sensitive to complement and whole-blood killing than was the parent strain. Finally, disruption of the htrA gene in a virulent K. pneumoniae strain caused a reduction of its virulence in a mice model. Our results indicate that the htrA gene plays an important role in the virulence of K. pneumoniae