Describing the heat shock response of Bacillus spp. under isothermal inactivation conditions

[ESP] El estrés ambiental y los métodos de procesamiento de alimentos, como el calentamiento, la acidez, son responsables de provocar respuestas adaptativas a las bacterias. La respuesta general al estrés en la mayoría de las bacterias Gram positivas, incluidas B. subtilis, L. monocytogenes, está regulada por el factor sigma alternativo σΒ que induce la transcripción de genes capaces de proporcionar a las células vegetativas resistencia al estrés. En este estudio, se analizó la resistencia al calor de las células vegetativas de B. subtilis bajo calentamiento isotérmico, así como la influencia de la ausencia del gen sigB en la resistencia al calor bacteriano. Los experimentos isotérmicos se llevaron a cabo en agua peptonada (pH 7) a 51, 52,5, 55 y 57,5°C y mostraron que ambas cepas eran bastante sensibles al calor. El mutante sigB presentó mayor inactivación a 51 y 52.5°C. [ENG] Adaptive responses to bacteria are triggered by environmental conditions and food processing processes such as heating and acidity. In the majority of Gram positive bacteria, including B. subtilis and L. monocytogenes, the overall stress response is governed by the alternative sigma factor σB (sigB), which stimulates the transcription of genes that provide resistance to stress to the vegetative cells. The heat resistance of B. subtilis vegetative cells was investigated under isothermal heating, as well as the effect of the sigB gene absence on bacterial heat resistance. Isothermal studies at 51, 52.5, 55, and 57.5°C in peptone water (pH 7) demonstrated that both strains were extremely heat sensitive. At 51 and 52.5°C, the sigB mutant presented more inactivation.Leonidas Georgalis is grateful for the “beca asociada a actividades de I+D+I”, convocatoria B- 077/20, for awarding him a pre−doctoral grant

Different model hypotheses are needed to account for qualitative variability in the response of two strains of Salmonella spp. under dynamic conditions

In this article, the thermal inactivation of two Salmonella strains (Salmonella Enteritidis CECT4300 and Salmonella Senftenberg CECT4565) was studied under both isothermal and dynamic conditions. We observed large differences between these two strains, with S. Senftenberg being much more resistant than S. Enteritidis. Under isothermal conditions, S. Senftenberg had non-linear survivor curves, whereas the response of S. Enteritidis was log-linear. Therefore, weibullian inactivation models were used to describe the response of S. Senftenberg, with the Mafart model being the more suitable one. For S. Enteritidis, the Bigelow (log-linear) inactivation model was successful at describing the isothermal response. Under dynamic conditions, a combination of the Peleg and Mafart models (secondary model of Mafart; t* of Peleg) fitted to the isothermal data could predict the response of S. Senftenberg to the dynamic treatments tested (heating rates between 0.5 and 10 °C/min). This was not the case for S. Enteritidis, where the model predictions based on isothermal data underestimated the microbial concentrations. Therefore, a dynamic model that considers stress acclimation to one of the dynamic profiles was fitted, using the remaining profiles as validation. In light of this, besides its quantitative impact, variability between strains of bacterial species can also cause qualitative differences in microbial inactivation. This is demonstrated by S. Enteritidis being able to develop stress acclimation where S. Senftenbenberg could not. This has important implications for the development of microbial inactivation models to support process design, as every industrial treatment is dynamic. Consequently, it is crucial to consider different model hypotheses, and how they affect the model predictions both under isothermal and dynamic conditions.The financial support of this research was provided by the Ministerio de Economía, Industria y Competitividad, Spain, through Project PID2020-116318RB-C32 and by FEDER funds. Dr. Alberto Garre was supported by a Maria Zambrano scholarship

Modelos matemáticos para la descripción del crecimiento de microorganismos patógenos en alimentos

[ESP] Los requerimientos actuales de calidad y seguridad microbiana en los alimentos sólo pueden ser satisfechos a través de una descripción detallada del comportamiento de los microorganismos patógenos durante el ciclo de vida del producto. La microbiología predictiva es clave en este aspecto, ya que describe por medio de modelos matemáticos la evolución de la población microbiana bajo diferentes condiciones ambientales. En esta contribución se presentan los modelos matemáticos más utilizados actualmente para la descripción de crecimiento microbiano. [ENG] Current standards on food quality and microbial safety can only be fulfilled through a detailed description of the behaviour of the pathogen microorganism during the life cycle of the product. Predictive microbiology serves a key role in this aspect. This science describes through mathematical models the evolution of a microbial population under different environmental conditions. This contribution presents the mathematical models most commonly used for the description of microbial growth.Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT), Escuela Técnica Superior de Ingeniería Agronómica (ETSIA), Escuela Técnica Superior de Ingeniería Industrial (ETSII), Escuela Técnica Superior de Arquitectura y Edificación (ETSAE), Escuela Técnica Superior de Ingeniería de Caminos, Canales y Puertos y de Ingeniería de Minas (ETSICCPIM), Facultad de Ciencias de la Empresa (FCCE), Parque Tecnológico de Fuente Álamo (PTFA), Vicerrectorado de Estudiantes y Extensión de la UPCT, Vicerrectorado de Investigación e Innovación de la UPCT, y Vicerrectorado de Internacionalización y Cooperación al Desarrollo de la UPCT

Dynamics of microbial Inactivation and acrylamide production in high-temperature heat treatments

In food processes, optimizing processing parameters is crucial to ensure food safety, maximize food quality, and minimize the formation of potentially toxigenic compounds. This research focuses on the simultaneous impacts that severe heat treatments applied to food may have on the formation of harmful chemicals and on microbiological safety. The case studies analysed consider the appearance/synthesis of acrylamide after a sterilization heat treatment for two different foods: pureed potato and prune juice, using Geobacillus stearothermophilus as an indicator. It presents two contradictory situations: on the one hand, the application of a high-temperature treatment to a low acid food with G. stearothermophilus spores causes their inactivation, reaching food safety and stability from a microbiological point of view. On the other hand, high temperatures favour the appearance of acrylamide. In this way, the two objectives (microbiological safety and acrylamide production) are opposed. In this work, we analyse the effects of high-temperature thermal treatments (isothermal conditions between 120 and 135 _C) in food from two perspectives: microbiological safety/stability and acrylamide production. After analysing both objectives simultaneously, it is concluded that, contrary to what is expected, heat treatments at higher temperatures result in lower acrylamide production for the same level of microbial inactivation. This is due to the different dynamics and sensitivities of the processes at high temperatures. These results, as well as the presented methodology, can be a basis of analysis for decision makers to design heat treatments that ensure food safety while minimizing the amount of acrylamide (or other harmful substances) produced.The financial support of this research work was provided by the Ministry of Science, Innovation and Universities of the Spanish Government and European Regional Development Fund (ERDF) through project AGL2017-86840-C2-1-R. J.L.P.-S. is grateful to the JAE-INTRO program from CSIC (Grant no JAEINT19_EX_0797). A.G. was supported by a postdoctoral grant from the Fundación Séneca (20900/PD/18)

Effect of the synergy of electric pulses and oregano essential oil in the inactivation of L. monocytogenes

[SPA] Listeria monocytogenes es actualmente una de las principales preocupaciones de la industria alimentaria. Aunque el número de casos reportados en la Unión Europea es relativamente, tiene una gran gravedad, con unas tasas de hospitalización y mortandad del 97% y del 16,7%, respectivamente. Debido a la ubicuidad de este microorganismo y su capacidad de crecer en numerosas matrices alimentarias, las empresas agroalimentarias deben aplicar tratamientos que inactiven las células de L. monocytogenes. En este trabajo, se estudió la cinética de inactivación de L. monocytogenes aislada de productos marinos sometida a un tratamiento combinado de PEAV con un aceite esencial de orégano. Los resultados demuestran esta sinergia, ya que se consiguió una mayor inactivación microbiana con un campo de 20 kV/cm, 1 Hz de frecuencia, 150 pulsos y una concentración de orégano de 1/2 MIC, superior a la obtenida en las muestras control. Llegando a la conclusión de que los PEAV impulsan el efecto del orégano sobre la membrana de la bacteria. [ENG] Nowadays Listeria monocytogenes is one of the main concerns of the food industry. The number of cases reported in the European Union is relatively low it is very serious, with rates of hospitalization and mortality of 97% and 16.7%, respectively. Due to the ubiquity of this organism and its capacity to grow in many food matrices, agri-food companies must apply treatments that inactivate the cells of L. monocytogenes. In this work, it was studied the kinetics of inactivation of L. monocytogenes isolated from marine products subjected to a combined treatment of PEF with an essential oil of oregano. The results show this synergy, since it got a greater inactivation microbial with a field of 20 KV/cm, 1 Hz frequency, 150 pulses and an oregano concentration of 1/2 MIC, higher than that obtained in control samples. Concluding that the PEF promote the effect of oregano on the bacterial cell membrane.Investigación apoyada por el MICINN (es) y FEDER a través de los proyectos AGL2017-86840-C2-1-R y AGL2016-82014-REDT

Prevalence of disability in a composite ≥75 year-old population in Spain: A screening survey based on the International Classification of Functioning

<p>Abstract</p> <p>Background</p> <p>The prevalence and predictors of functional status and disability of elderly people have been studied in several European countries including Spain. However, there has been no population-based study incorporating the International Classification of Functioning, Disability and Health (ICF) framework as the basis for assessing disability. The present study reports prevalence rates for mild, moderate, and severe/extreme disability by the domains of activities and participation of the ICF.</p> <p>Methods</p> <p>Nine populations surveyed in previous prevalence studies contributed probabilistic and geographically defined samples in June 2005. The study sample was composed of 503 subjects aged ≥75 years. We implemented a two-phase screening design using the MMSE and the World Health Organization-Disability Assessment Schedule 2^ndedition (WHO-DAS II, 12 items) as cognitive and disability screening tools, respectively. Participants scoring within the positive range of the disability screening were administered the full WHO-DAS II (36 items; score range: 0-100) assessing the following areas: Understanding and communication, Getting along with people, Life activities, Getting around, Participation in society, and Self-care. Each disability area assessed by WHO-DAS II (36 items) was reported according to the ICF severity ranges (No problem, 0-4; Mild disability, 5-24; Moderate disability, 25-49; Severe/Extreme disability, 50-100).</p> <p>Results</p> <p>The age-adjusted disability prevalence figures were: 39.17 ± 2.18%, 15.31 ± 1.61%, and 10.14 ± 1.35% for mild, moderate, and severe/extreme disability, respectively. Severe and extreme disability prevalence in mobility and life activities was three times higher than the average, and highest among women. Sex variations were minimal, although life activities for women of 85 years and over had more severe/extreme disability as compared to men (OR = 5.15 95% CI 3.19-8.32).</p> <p>Conclusions</p> <p>Disability is highly prevalent among the Spanish elderly. Sex- and age-specific variations of disability are associated with particular disability domains.</p

Cumulative Genetic Score and C9orf72 Repeat Status Independently Contribute to Amyotrophic Lateral Sclerosis Risk in 2 Case-Control Studies

[Background and Objectives] Most patients with amyotrophic lateral sclerosis (ALS) lack a monogenic mutation. This study evaluates ALS cumulative genetic risk in an independent Michigan and Spanish replication cohort using polygenic scores.[Methods] Participant samples from University of Michigan were genotyped and assayed for the chromosome 9 open reading frame 72 hexanucleotide expansion. Final cohort size was 219 ALS and 223 healthy controls after genotyping and participant filtering. Polygenic scores excluding the C9 region were generated using an independent ALS genome-wide association study (20,806 cases, 59,804 controls). Adjusted logistic regression and receiver operating characteristic curves evaluated the association and classification between polygenic scores and ALS status, respectively. Population attributable fractions and pathway analyses were conducted. An independent Spanish study sample (548 cases, 2,756 controls) was used for replication.[Results] Polygenic scores constructed from 275 single-nucleotide variation (SNV) had the best model fit in the Michigan cohort. An SD increase in ALS polygenic score associated with 1.28 (95% CI 1.04–1.57) times higher odds of ALS with area under the curve of 0.663 vs a model without the ALS polygenic score (p value = 1 × 10−6). The population attributable fraction of the highest 20th percentile of ALS polygenic scores, relative to the lowest 80th percentile, was 4.1% of ALS cases. Genes annotated to this polygenic score enriched for important ALS pathomechanisms. Meta-analysis with the Spanish study, using a harmonized 132 single nucleotide variation polygenic score, yielded similar logistic regression findings (odds ratio: 1.13, 95% CI 1.04–1.23).[Discussion] ALS polygenic scores can account for cumulative genetic risk in populations and reflect disease-relevant pathways. If further validated, this polygenic score will inform future ALS risk models.National ALS Registry/CDC/ATSDR (1R01TS000289); National ALS Registry/CDC/ATSDR CDCP-DHHS-US (CDC/ATSDR 200-2013-56856); NIEHS K23ES027221; NIEHS R01ES030049; NINDS R01NS127188, ALS Association (20-IIA-532), the Dr. Randall W. Whitcomb Fund for ALS Genetics, the Peter R. Clark Fund for ALS Research, the Scott L. Pranger ALS Clinic Fund, and the NeuroNetwork for Emerging Therapies at the University of Michigan. This work was supported in part by the Intramural Research Program of the NIH, National Institute on Aging (Z01-AG000949-02). Project “ALS Genetic study in Madrid Autonomous Community” funded by “ESTRATEGIAS FRENTE A ENFERMEDADES NEURODEGENERATIVAS” from Spanish Ministry of Health.Peer reviewe

Genome-wide association analysis of dementia and its clinical endophenotypes reveal novel loci associated with Alzheimer's disease and three causality networks : The GR@ACE project

Introduction: Large variability among Alzheimer's disease (AD) cases might impact genetic discoveries and complicate dissection of underlying biological pathways. Methods: Genome Research at Fundacio ACE (GR@ACE) is a genome-wide study of dementia and its clinical endophenotypes, defined based on AD's clinical certainty and vascular burden. We assessed the impact of known AD loci across endophenotypes to generate loci categories. We incorporated gene coexpression data and conducted pathway analysis per category. Finally, to evaluate the effect of heterogeneity in genetic studies, GR@ACE series were meta-analyzed with additional genome-wide association study data sets. Results: We classified known AD loci into three categories, which might reflect the disease clinical heterogeneity. Vascular processes were only detected as a causal mechanism in probable AD. The meta-analysis strategy revealed the ANKRD31-rs4704171 and NDUFAF6-rs10098778 and confirmed SCIMP-rs7225151 and CD33-rs3865444. Discussion: The regulation of vasculature is a prominent causal component of probable AD. GR@ACE meta-analysis revealed novel AD genetic signals, strongly driven by the presence of clinical heterogeneity in the AD series

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues