Bacteriophage induction versus vaginal homeostasis: role of H2O2 in the selection of Lactobacillus defective prophages

Vaginal disorders associated with systemic chemotherapy arise by direct inhibition of the resident microbiota (dominated by lactobacilli) or, possibly, by induction of prophages harbored in their genomes, leading to cell lysis. In the present study, proficient Lactobacillus phages could not be isolated from vaginal exudates. However, lysogeny appeared to be widespread, although about half of the strains harbored prophage sequences that were not responsive to SOS activation. In other cases, prophage induction was achieved, but viable phages were not generated, despite the fact that the induced supernatants of some strains were bactericidal. In one case, this activity was accompanied by the production of a bacteriophage subsequently identified as a member of the family Siphoviridae (isometric capsid and long non-contractile tail). Most of the lactobacilli tested generated hydrogen peroxide, which acted as an inducer of the SOS response, suggesting that H2O2 selects for strains that harbor SOS-insensitive, defective prophages, which are thus unable to promote vaginal lactobacilli phageinduced lysis. [Int Microbiol 2009; 12(2):131-136

Insight into the Lytic Functions of the Lactococcal Prophage TP712

The lytic cassette of Lactococcus lactis prophage TP712 contains a putative membrane protein of unknown function (Orf54), a holin (Orf55), and a modular endolysin with a N-terminal glycoside hydrolase (GH_25) catalytic domain and two C-terminal LysM domains (Orf56, LysTP712). In this work, we aimed to study the mode of action of the endolysin LysTP712. Inducible expression of the holin-endolysin genes seriously impaired growth. The growth of lactococcal cells overproducing the endolysin LysTP712 alone was only inhibited upon the dissipation of the proton motive force by the pore-forming bacteriocin nisin. Processing of a 26-residues signal peptide is required for LysTP712 activation, since a truncated version without the signal peptide did not impair growth after membrane depolarization. Moreover, only the mature enzyme displayed lytic activity in zymograms, while no lytic bands were observed after treatment with the Sec inhibitor sodium azide. LysTP712 might belong to the growing family of multimeric endolysins. A C-terminal fragment was detected during the purification of LysTP712. It is likely to be synthesized from an alternative internal translational start site located upstream of the cell wall binding domain in the lysin gene. Fractions containing this fragment exhibited enhanced activity against lactococcal cells. However, under our experimental conditions, improved in vitro inhibitory activity of the enzyme was not observed upon the supplementation of additional cell wall binding domains in. Finally, our data pointed out that changes in the lactococcal cell wall, such as the degree of peptidoglycan O-acetylation, might hinder the activity of LysTP712. LysTP712 is the first secretory endolysin from a lactococcal phage described so far. The results also revealed how the activity of LysTP712 might be counteracted by modifications of the bacterial peptidoglycan, providing guidelines to exploit the biotechnological potential of phage endolysins within industrially relevant lactococci and, by extension, other bacteria

Bacteriophage induction versus vaginal homeostasis: Role of H2O2 in the selection of Lactobacillus defective prophages

Vaginal disorders associated with systemic chemotherapy arise by direct inhibition of the resident microbiota (dominated by lactobacilli) or, possibly, by induction of prophages harbored in their genomes, leading to cell lysis. In the present study, proficient Lactobacillus phages could not be isolated from vaginal exudates. However, lysogeny appeared to be widespread, although about half of the strains harbored prophage sequences that were not responsive to SOS activation. In other cases, prophage induction was achieved, but viable phages were not generated, despite the fact that the induced supernatants of some strains were bactericidal. In one case, this activity was accompanied by the production of a bacteriophage subsequently identified as a member of the family Siphoviridae (isometric capsid and long non-contractile tail). Most of the lactobacilli tested generated hydrogen peroxide, which acted as an inducer of the SOS response, suggesting that H2O2 selects for strains that harbor SOS-insensitive, defective prophages, which are thus unable to promote vaginal lactobacilli phage-induced lysis

Reduced Binding of the Endolysin LysTP712 to Lactococcus lactis ΔftsH Contributes to Phage Resistance

Absence of the membrane protease FtsH in Lactococcus lactis hinders release of the bacteriophage TP712. In this work we have analyzed the mechanism responsible for the non-lytic phenotype of L. lactis ΔftsH after phage infection. The lytic cassette of TP712 contains a putative antiholin–pinholin system and a modular endolysin (LysTP712). Inducible expression of the holin gene demonstrated the presence of a dual start motif which is functional in both wildtype and L. lactis ΔftsH cells. Moreover, simulating holin activity with ionophores accelerated lysis of wildtype cells but not L. lactis ΔftsH cells, suggesting inhibition of the endolysin rather than a role of FtsH in holin activation. However, zymograms revealed the synthesis of an active endolysin in both wildtype and L. lactis ΔftsH TP712 lysogens. A reporter protein was generated by fusing the cell wall binding domain of LysTP712 to the fluorescent mCherry protein. Binding of this reporter protein took place at the septa of both wildtype and L. lactis ΔftsH cells as shown by fluorescence microscopy. Nonetheless, fluorescence spectroscopy demonstrated that mutant cells bound 40% less protein. In conclusion, the non-lytic phenotype of L. lactis ΔftsH is not due to direct action of the FtsH protease on the phage lytic proteins but rather to a putative function of FtsH in modulating the architecture of the L. lactis cell envelope that results in a lower affinity of the phage endolysin to its substrate.This work has been supported by grant BIO2013-46266R (MINECO, Spain). BM, PG, and AR also acknowledge funding by GRUPIN14-139 Plan de Ciencia, Tecnología e Innovación 2013-2017 (Principado de Asturias, Spain) and FEDER EU funds.Peer reviewe

Diversity and Bioprospection of Gram-positive Bacteria Derived from a Mayan Sinkhole

Funding Information: We would like to thank CONAHCyT, FQ, UNAM-PAIP, and FCT-Funda\u00E7\u00E3o para a Ci\u00EAncia e a Tecnologia for their financial support. J.L.W. and J.C.P.-F. are grateful for financial aid provided by UNAM-DGAPA in the form of a postdoctoral fellowship. We are also grateful to the Brady Laboratory at the Rockefeller University N.Y. for their support with funding for cave sampling, and to Efra\u00EDn Ch\u00E1vez Sol\u00EDs, Luis A. Li\u00E9vano Beltr\u00E1n and Kay Vilchis Zapata for their invaluable help reaching the remote depths and lengths of the anchialine cave system in the Yucat\u00E1n. We would like to thank Sebastien Santini (CNRS/AMU IGS UMR7256) and the PACA Bioinfo platform for the availability and management of the phylogeny.fr website used to generate alignments and the phylogenetic trees. Funding Information: Funding for this research was provided by multiple sources. J.L.W. and J.C.P.-F. were both supported in the form of postdoctoral fellowships provided by UNAM-DGAPA. W.E.-H. was supported by the UNAM-PAPIIT IA203722. A.P.-D. received support from the Consejo Nacional de Humanidades Ciencias y Tecnologías (CONAHCyT) through the Ciencia Básica grant number A1-S-10785, as well as a sabbatical grant. Additionally, A.P.-D. received support from the School of Chemistry, UNAM PAIP program grant 5000-9149. Publisher Copyright: © The Author(s) 2024.Water-filled sinkholes known locally as cenotes, found on the Yucatán Peninsula, have remarkable biodiversity. The primary objective of this study was to explore the biotechnological potential of Gram-positive cultivable bacteria obtained from sediment samples collected at the coastal cenote Pol-Ac in Yucatán, Mexico. Specifically, the investigation aimed to assess production of hydrolytic enzymes and antimicrobial compounds. 16 S rRNA gene sequencing led to the identification of 49 Gram-positive bacterial isolates belonging to the phyla Bacillota (n = 29) and Actinomycetota (n = 20) divided into the common genera Bacillus and Streptomyces, as well as the genera Virgibacillus, Halobacillus, Metabacillus, Solibacillus, Neobacillus, Rossellomorea, Nocardiopsis and Corynebacterium. With growth at 55ºC, 21 of the 49 strains were classified as moderately thermotolerant. All strains were classified as halotolerant and 24 were dependent on marine water for growth. Screening for six extracellular hydrolytic enzymes revealed gelatinase, amylase, lipase, cellulase, protease and chitinase activities in 93.9%, 67.3%, 63.3%, 59.2%, 59.2% and 38.8%, of isolated strains, respectively. The genes for polyketide synthases type I, were detected in 24 of the strains. Of 18 strains that achieved > 25% inhibition of growth in the bacterial pathogen Staphylococcus aureus ATCC 6538, 4 also inhibited growth in Escherichia coli ATCC 35,218. Isolates Streptomyces sp. NCA_378 and Bacillus sp. NCA_374 demonstrated 50–75% growth inhibition against at least one of the two pathogens tested, along with significant enzymatic activity across all six extracellular enzymes. This is the first comprehensive report on the biotechnological potential of Gram-positive bacteria isolated from sediments in the cenotes of the Yucatán Peninsula.publishersversionepub_ahead_of_prin

Cell wall modifications that alter the exolytic activity of lactococcal phage endolysins have little impact on phage growth

Bacteriophages are a nuisance in the production of fermented dairy products driven by starter bacteria and strategies to reduce the risk of phage infection are permanently sought. Bearing in mind that the bacterial cell wall plays a pivotal role in host recognition and lysis, our goal was to elucidate to which extent modifications in the cell wall may alter endolysin activity and influence the outcome of phage infection in Lactococcus. Three lactococcal endolysins with distinct catalytic domains (CHAP, amidase and lysozyme) from phages 1,358, p2 and c2 respectively, were purified and their exolytic activity was tested against lactococcal mutants either overexpressing or lacking genes involved in the cell envelope stress (CES) response or in modifying peptidoglycan (PG) composition. After recombinant production in E. coli, Lys1358 (CHAP) and LysC2 (muramidase) were able to lyse lactococcal cells in turbidity reduction assays, but no activity of LysP2 was detected. The degree of PG acetylation, namely C6-O-acetylation and de-N-acetylation influenced the exolytic activity, being LysC2 more active against cells depleted of the PG deacetylase PgdA and the O-acetyl transferase OatA. On the contrary, both endolysins showed reduced activity on cells with an induced CES response. By measuring several growth parameters of phage c2 on these lactococcal mutants (lytic score, efficiency of plaquing, plaque size and one-step curves), a direct link between the exolytic activity of its endolysin and phage performance could not be stablished

Buenas prácticas de valorización en el proceso de adquisición realizadas por empresas del sistema financiero peruano. Los casos de: Banco de Crédito del Perú, Interbank, Pichincha y Scotiabank Perú

El presente trabajo de investigación tiene como propósito dar a conocer las buenas prácticas empleadas por empresas del sistema financiero peruano. Para tal fin este trabajo de investigación presenta resultados de un estudio descriptivo y cualitativo en el cual se logra identificar las buenas prácticas financieras de valorización empleadas por las empresas seleccionadas del sistema financiero del Perú en adquisición de empresas, durante los años 2013 al 2018. Se tomó los casos del Banco de Crédito del Perú, Interbank, Pichincha y Scotiabank Perú, con la finalidad de recomendar la implementación de los resultados obtenidos en otras empresas más pequeñas o con menos experiencia en el sector y así ayudarlas a mejorar su gestión al realizar una adquisición. Se partió del estudio sobre la base teórica de los métodos de valorización, así como de los datos obtenidos en experiencias de adquisiciones previas en Latinoamérica y en el Perú; siendo contrastada la información teórica recolectada con la información obtenida mediante la realización de entrevistas a los principales ejecutivos tomadores de decisión responsables de la respectiva área de interés en la administración financiera de cada una de las empresas estudiadas, y así poder responder a las preguntas de investigación del presente estudio.The purpose of this research work is to present good practices used by companies in the Peruvian financial system. To this end, this research work presents results of a descriptive and qualitative study in which it is possible to identify the good financial valuation practices employed by the selected companies of the Peruvian financial system in acquisition of companies, during the years 2013 to 2018. The cases of: Banco de Crédito del Perú, Interbank, Pichincha and Scotiabank Perú. In order to be able to recommend the implementation of the results obtained in other smaller companies or with less experience in the sector and thus help them improve their management when making an acquisition. Starting the study on the theoretical basis of the valuation methods, as well as the data obtained in previous acquisition experiences in Latin America and Peru; The theoretical information collected is contrasted with the information obtained by conducting interviews with the main decision-making executives responsible for the respective area of interest in the financial administration of each of the companies studied, and thus be able to answer the research questions of the present study.Tesi

Barreras Para La Práctica Del Ejercicio Durante El Confinamiento Por Covid-19 En Docentes De La Uaz

The confinement by covid-19 generated a decrease in physical exercise and consequently a higher risk of suffering from various diseases. Objective: to know the barriers for the practice of exercise during the confinement by COVID-19 in teachers of the Autonomous University of Zacatecas (UAZ) in the semester August-December 2020. A descriptive, analytical and cross-sectional study was conducted with a quantitative approach, An On-line survey developed in the Google Forms application was volunteered, using a non-parametric descriptive statistical test, CI 72%= (-1.09;1.09). The total sample was 437 subjects; it was found that 72% of the population does exercise, where it was concluded that the main barrier to exercise is disinterest, overwork and lack of knowledge to have a well-planned training. This is followed by injuries and illnesses that prevent them from exercising

Trichinellosis: nuevos enfoques y cambio global

El presente trabajo está enfocado al análisis del impacto de la trichinellosis como enfermedad reemergente, con impacto en la salud global, su distribución geográfica, su presencia en diferentes huéspedes animales. Los parásitos afectan la salud de millones de personas cada año. Infectan tejidos musculares, piel y órganos, causando trastornos neurológicos, choques anafilácticos, alteraciones de la función intestinal, y otra serie de problemas, en muchos casos no son mortales pero sí disminuyen la calidad de vida. Algunos parásitos pueden vivir en el cuerpo humano durante décadas. En julio de 2014 la FAO y la OMS publicaron la lista de los 10 parásitos que se trasmiten por alimentos colocando en el séptimo lugar a la Trichinellosis. La trichinellosis es una zoonosis endémica reportada como una enfermedad reemergente. Se ha observado un aumento de los casos en humanos como en animales. Impactan en su presencia los cambios sociales, económicos, políticos, ambientales, migratorios, etc. La trichinellosis es una enfermedad parasitaria causada por el nematodo Trichinella spiralis (en la mayoría de los casos pero actualmente otras especies también pueden infectar al hombre y otros huéspedes animales). Afecta a mamíferos silvestres y domésticos. Se ha reportado en casi todo el mundo y su prevalecía es alta en Europa y Asia. Se transmite de modo accidental al hombre por ingestión de carne o productos cárnicos crudos o insuficientemente cocinados, procedentes de animales infectados. La principal fuente de infección para el hombre es el cerdo. Es importante mencionar la dificultad y baja incidencia de detección de la enfermedad, el ineficiente control sanitario en la canal del cerdo contaminado y la práctica frecuente de matanza clandestina en animales de trans-patio. La trichinellosis es una enfermedad silenciosa ya que no ocasiona de manera habitual la muerte pero sí disminuye la calidad de vida.Trabajo publicado en Acta Bioquímica Clínica Latinoamericana; no. 52, supl. 2, parte II, diciembre de 2018.Universidad Nacional de La Plat