Cinética de crecimiento de bacterias ácido- lácticas autóctonas aisladas de “queso doble crema” con potencial para un cultivo iniciador

Currently, there is a permanent search for native Lactic Acid Bacteria (LAB) to explore and apply their biodiversity in the development and improvement of industrial processes, with studies of growth kinetics and performance factors being a fundamental tool for biotechnological use. The objective of this study was to determine the kinetic parameters of 12 autochthonous strains (Pediococcus pentosaceus (19), Leuconostoc citreum (20), Pediococcus acidilactici (21), Leuconostoc mesenteroides subsp. Mesenteroides (22, 29), Enterococcus faecium (24, 25), Enterococcus faecalis (27), Weissella viridescens (28), Lactococcus lactis (30), Lacticaseibacillus casei (31) and Limosilactobacillus fermentum (32)) isolated from a traditional Colombian cheese Double Cream Cheese to obtain information that allows establishing the ideal conditions of the inoculum, standardizing the production of metabolites and exploring their use as starter cultures. Fermentation was carried out in UHT milk at 120 rpm and 35-37 °C until stationary phase, and samples were taken over time to determine pH and titratable acidity (TTA). Exponential and logistic models were used to fit the growth kinetics data. Validation of both models was carried out with the coefficient of determination R2, obtaining good consistency for both (R2 = 0.925 - R2 = 0.932), with slight variations in the kinetic parameters in all the strains. The genera Pediococcus, Leuconostoc, Lactococcus, and E. faecium (24) had the shortest adaptation phases (0-2 h), being P. acidilactici (21), Leu. mesenteroides (22), W. viridescens (28), and E. faecium (24) presented the lowest pH values and high acidity percentages, which shows their potential to be included in the native LAB starter culture and for technology and suitability aptitude studies to produce double cream cheese using pasteurized milk without losing the qualities of the original product.Actualmente, existe una búsqueda permanente de bacterias ácido-lácticas (BAL) autóctonas para explorar y aplicar su biodiversidad en el desarrollo y mejoramiento de procesos industriales, siendo los estudios de cinética de crecimiento y los factores de rendimiento una herramienta fundamental para la utilización biotecnológica. Este trabajo tuvo como objetivo determinar los parámetros cinéticos de 12 cepas autóctonas (Pediococcus pentosaceus (19), Leuconostoc citreum (20), Pediococcus acidilactici (21), Leuconostoc mesenteroides subsp. Mesenteroides (22, 29), Enterococcus faecium (24, 25), Enterococcus faecalis (27), Weissella viridescens (28), Lactococcus lactis (30), Lacticaseibacillus casei (31) y Limosilactobacillus fermentum (32)) aisladas de un queso doble crema tradicional colombiano con el fin de obtener información para identificar su potencial en la conformación de un cultivo iniciador. Se realizó una fermentación en leche UHT a 120 rpm y 35-37 °C hasta la fase estacionaria, y se tomaron muestras para determinar el pH y la acidez titulable (TTA). Se emplearon los modelos exponencial y logístico para ajustar los datos de la cinética de crecimiento. La validación de ambos modelos se realizó empleando el coeficiente de correlación R2, presentando buena consistencia en ambos (R2 = 0.925 - R2 = 0.932) con variaciones en los parámetros cinéticos en todas las cepas. Los géneros Pediococcus, Leuconostoc, Lactococcus y E. faecium (24) tuvieron las fases de adaptación más cortas (0-2 h), siendo P. acidilactici (21), Leu. mesenteroides (22), W. viridescens (28) y E. faecium (24) quienes presentaron los menores valores de pH y altos porcentajes de acidez. Esto evidencia su potencial para ser incluidas en el cultivo iniciador de BAL autóctonos y en estudios de aptitud tecnológica e idoneidad para la elaboración del queso tipo doble crema utilizando leche pasteurizada sin perder las cualidades del producto original

Comparison of the pulmonary function of patients with type 2 diabetes mellitus treated with insulin injections versus that of patients treated with oral hypoglucemic agents

Introducción: la potencial asociación entre el tipo de tratamiento de la diabetes mellitus tipo 2 (DM2) y alteración de la función pulmonar es algo poco estudiado hasta ahora. Objetivos: comparar la función pulmonar de pacientes con DM2 que reciben tratamiento con insulina inyectable versus hipoglicemiantes orceles (HO). Determinar si niveles de marcadores de inflamación en pacientes con tratamiento basado en insulina son diferentes a los de los tratados con HO. Métodos: estudio observational analítico de corte transversal a partir de una muestra de conveniencia de 369 pacientes con diagnóstico de DM2, y tratamiento con insulina o HO. Se realizaron espirometrías, y se obtuvieron valores residuales promedios para VEF1, CVF y relación VEF1/CVF. Mediante regresión lineal múltiple, se ajustó por diferencias en determinantes conocidos de la función pulmonar, así como por control de la diabetes y tiempo desde el diagnóstico. Adicionalmente, se midieron niveles de marcadores inflamatorios sanguíneos para cada grupo de tratamiento. Resultados: 63 pacientes (17%) recibían tratamiento con insulina y 306 (83%) con HO. La diferencia en residuales faxoreció a los tratados con HO. Para VEF1, CVF y VEF1/CVF la diferencia fue 57.6 mL (IC95% 32.45-82.74; P 0.0047), 45.6 mL (IC95% 20.84-70.39; P 0.0231) y 0.017, (IC95% 0.01-0.02, PcO.0001), respectivamente. No hubo cambios estadísticamente significativos en marcadores de inflamación. Conclusiones: los pacientes en tratamiento con HO presentaron mejor función pulmonar que los tratados con insulina. Este hallazgo de diferencias en función pulmonar pudiera tener implicación clínica en el manejo de los pacientes diabéticos, pero debe confirmarse en estudios prospectivos.Artículo original113-118Introduction: the potential association between the type of treatment of type 2 diabetes mellitus (DM2) and impaired lung function is something rarely studied so far. Objectives: to compare the lung function of patients with DM2 who are treated with injectable insulin versus HO. To determine whether levels of inflammatory markers in patients with insulin-based treatment are different from those treated with HO. Methods: an observational, analytical, cross-sectional study from a convenience sample of 369 patients diagnosed with DM2 and treated with insulin or HO. Spirometry was performed, and residual values were averaged for FEV1, FVC and FEV1/FVC ratios. Multiple linear regression results were adjusted by differences in known determinants of lung function, as well as control of diabetes and time since diagnosis. Additionally, we measured blood levels of inflammatory markers for each treatment group. Results: 63 patients (17%) were treated with insulin and 306 (83%) with OH. The difference in residual favored those treated with HO. For FEV1, FVC and FEV1/FVC the difference was 57.6 mL (95% CI 32.45 to 82.74, P 0.0047), 45.6 mL (95% CI 20.84 to 70.39, P 0.0231) and 0.017 (95% CI 0.01 to 0.02, P <0.0001), respectively. There were no statistically significant changes in inflammation markers. Conclusions: patients treated with HO showed better lung function than those treated with insulin. This finding of differences in lung function may have clinical implications in the management of diabetic patients, but needs to be confirmed in prospective studies

Actividad bacteriocinogénica de bacterias aisladas de digestivos de peces marinos salvajes

El crecimiento exponencial que ha sufrido la acuicultura en las últimas décadas ha dado lugar a un incremento en número y virulencia de las enfermedades bacterianas que afectan a los peces cultivados. Hasta la fecha, el control de estas enfermedades se ha realizado a través del uso de vacunas y antibióticos, así como de la desinfección del agua y el control biológico, el uso de inmunoestimulantes no-específicos y suplementos dietéticos, entre otros. Pero una mala gestión de estas enfermedades, asociada sobre todo al abuso de antibióticos, ha sido asociada a la aparición de reservorios de bacterias resistentes a antibióticos, tanto en animales como en el ambiente acuático, con el consiguiente peligro para la salud humana (1, 2). El empleo de bacteriocinas como alternativa a los antibióticos parece ser una alternativa plausible para el control y tratamiento de estas enfermedades de una manera inocua y sostenible (3, 4). Pese a que en los últimos años se ha intensificado la búsqueda de cepas productoras de bacteriocinas frente a bacterias patógenas marinas, desafortunadamente todavía son pocas las cepas totalmente caracterizadas (5). El presente estudio tiene por objetivo caracterizar cepas bacterianas con actividad bacteriocinogénica aisladas de intestinos de peces salvajes del Mar Cantábrico. Para ello se procesaron un total de 19 intestinos pertenecientes a 19 ejemplares, cada uno de una especie diferente capturados en el Mar Cantábrico (Cantabria). De estas muestras se aislaron un total de 198 colonias en medio de cultivo TSA, en base a su morfología, color y brillo, que fueron seleccionadas para comprobar su actividad antagonista frente a patógenos de peces de acuicultura. Como cepas indicadoras patógenas de peces se emplearon: Vibrio splendidus y Vibrio anguillarum, y cepas patógenas aisladas de cultivos de lenguado senegalés (Solea senegalensis). Se detectaron 15 cepas de bacterias marinas que presentaban actividad antagonista frente al menos una de las cepas patógenas, de las cuales 4 mostraron actividad inhibitoria frente a más de una especie patógena. La identificación de las cepas procedentes del medio marino seleccionadas se realizó mediante la secuenciación del gen 16S ARN, presentando una homología >99% a Myroides sp. y Alcaligenes sp. Finalmente se estudió el efecto de los parámetros físico-químicos en la actividad bactericida (pH, temperatura y proteasas)

Effectiveness and Safety of the Switch from Remicade® to CT-P13 in Patients with Inflammatory Bowel Disease

BACKGROUND AND AIMS: To evaluate the clinical outcomes in patients with IBD after switching from Remicade® to CT-P13 in comparison with patients who maintain Remicade®. METHODS: Patients under Remicade® who were in clinical remission with standard dosage at study entry were included. The ''switch cohort'' [SC] comprised patients who made the switch from Remicade® to CT-P13, and the ''non-switch'' cohort [NC] patients remained under Remicade®. RESULTS: A total of 476 patients were included: 199 [42%] in the SC and 277 [58%] in the NC. The median follow-up was 18 months in the SC and 23 months in the NC [p < 0.01]. Twenty-four out of 277 patients relapsed in the NC; the incidence of relapse was 5% per patient-year. The cumulative incidence of relapse was 2% at 6 months and 10% at 24 months in this group. Thirty-eight out of 199 patients relapsed in the SC; the incidence rate of relapse was 14% per patient-year. The cumulative incidence of relapse was 5% at 6 months and 28% at 24 months. In the multivariate analysis, the switch to CT-P13 was associated with a higher risk of relapse (HR = 3.5, 95% confidence interval [CI] = 2-6). Thirteen percent of patients had adverse events in the NC, compared with 6% in the SC [p < 0.05]. CONCLUSIONS: Switching from Remicade® to CT-P13 might be associated with a higher risk of clinical relapse, although this fact was not supported in our study by an increase in objective markers of inflammation. The nocebo effect might have influenced this result. Switching from Remicade® to CT-P13 was safe

Real-Time PCR Improves Helicobacter pylori Detection in Patients with Peptic Ulcer Bleeding

Background and aims: Histological and rapid urease tests to detect H. pylori in biopsy specimens obtained during peptic ulcer bleeding episodes (PUB) often produce false-negative results. We aimed to examine whether immunohistochemistry and real-time PCR can improve the sensitivity of these biopsies. Patients and Methods: We selected 52 histology-negative formalin-fixed paraffin-embedded biopsy specimens obtained during PUB episodes. Additional tests showed 10 were true negatives and 42 were false negatives. We also selected 17 histology-positive biopsy specimens obtained during PUB to use as controls. We performed immunohistochemistry staining and real-time PCR for 16S rRNA, ureA, and 23S rRNA for H. pylori genes on all specimens. Results: All controls were positive for H. pylori on all PCR assays and immunohistochemical staining. Regarding the 52 initially negative biopsies, all PCR tests were significantly more sensitive than immunohistochemical staining (p<0.01). Sensitivity and specificity were 55% and 80% for 16S rRNA PCR, 43% and 90% for ureA PCR, 41% and 80% for 23S rRNA PCR, and 7% and 100% for immunohistochemical staining, respectively. Combined analysis of PCR assays for two genes were significantly more sensitive than ureA or 23S rRNA PCR tests alone (p<0.05) and marginally better than 16S rRNA PCR alone. The best combination was 16S rRNA+ureA, with a sensitivity of 64% and a specificity of 80%. Conclusions: Real-time PCR improves the detection of H. pylori infection in histology-negative formalin-fixed paraffin-embedded biopsy samples obtained during PUB episodes. The low reported prevalence of H. pylori in PUB may be due to the failure of conventional tests to detect infection

The effect of skewness and kurtosis on the robustness of linear mixed models

This study analyzes the robustness of the linear mixed model (LMM) with the Kenward–Roger (KR) procedure to violations of normality and sphericity when used in split-plot designs with small sample sizes. Specifically, it explores the independent effect of skewness and kurtosis on KR robustness for the values of skewness and kurtosis coefficients that are most frequently found in psychological and educational research data. To this end, a Monte Carlo simulation study was designed, considering a split-plot design with three levels of the between-subjects grouping factor and four levels of the within-subjects factor. Robustness is assessed in terms of the probability of type I error. The results showed that (1) the robustness of the KR procedure does not differ as a function of the violation or satisfaction of the sphericity assumption when small samples are used; (2) the LMM with KR can be a good option for analyzing total sample sizes of 45 or larger when their distributions are normal, slightly or moderately skewed, and with different degrees of kurtosis violation; (3) the effect of skewness on the robustness of the LMM with KR is greater than the corresponding effect of kurtosis for common values; and (4) when data are not normal and the total sample size is 30, the procedure is not robust. Alternative analyses should be performed when the total sample size is 30

Structural insight into the membrane targeting domain of the Legionella deAMPylase SidD

AMPylation, the post-translational modification with adenosine monophosphate (AMP), is catalyzed by effector proteins from a variety of pathogens. Legionella pneumophila is thus far the only known pathogen that, in addition to encoding an AMPylase (SidM/DrrA), also encodes a deAMPylase, called SidD, that reverses SidM-mediated AMPylation of the vesicle transport GTPase Rab1. DeAMPylation is catalyzed by the N-terminal phosphatase-like domain of SidD. Here, we determined the crystal structure of full length SidD including the uncharacterized C-terminal domain (CTD). A flexible loop rich in aromatic residues within the CTD was required to target SidD to model membranes in vitro and to the Golgi apparatus within mammalian cells. Deletion of the loop (??loop) or substitution of its aromatic phenylalanine residues rendered SidD cytosolic, showing that the hydrophobic loop is the primary membrane-targeting determinant of SidD. Notably, deletion of the two terminal alpha helices resulted in a CTD variant incapable of discriminating between membranes of different composition. Moreover, a L. pneumophila strain producing SidD??loop phenocopied a L. pneumophila ??sidD strain during growth in mouse macrophages and displayed prolonged co-localization of AMPylated Rab1 with LCVs, thus revealing that membrane targeting of SidD via its CTD is a critical prerequisite for its ability to catalyze Rab1 deAMPylation during L. pneumophila infection