Inhibitory action of essential oils against proteases activity of Paenibacillus larvae, the etiological agent of American Foulbrood disease

American foulbrood (AFB) is a disease affecting the larva of Apis mellifera. The etiological agent is Paenibacillus larvae, which releases metalloproteases involved in the degradation of larval tissues. Through quorum sensing (QS) mechanism, bacteria are able to activate specific genes such as virulence factors. The exoproteases regulation of P. larvae could be associated with QS. A promising mechanism of AFB control is to block QS mechanism with essential oils (EO). The aim of this study was to investigate the potential presence of QS signals in the regulation of P. larvae proteases and the effect of seven EOs on the exoproteases activity of P. larvae. From growth curves and evaluation of the presence of proteases by milk agar plates assay, it was observed protease activity during the late exponential phase of growth. Early production of protease activity (15 hours earlier than control) was observed when a low density culture was incubated with late exponential spent medium (SM) suggesting the presence of factor(s) inducing this activity. SM was obtained by the ultrafiltration of P. larvae cultures on late growth phase and was free of proteases. Proteolytic activity was quantified on P. larvae cultures in presence of sublethal concentration of EO by azocasein method. The EOs, except S. chilensis EO, reduced significantly protease activity (more than 50%). We report for the first time evidence on the possible role of QS on P. larvae and the antiproteolytic activity of EOs (except for S. chilensis) on exoproteases, an interesting therapeutic strategy to control AFB

Seminal plasma proteins modify the distribution of sperm subpopulations in cryopreserved semen of rams with lesser fertility

P. 44-50Any physiological mechanism involved in sperm selection and semen improvement has effects on heterogeneous sperm populations. This is mainly due to the fact that sperm populations within a single ejaculate have considerable heterogeneity for many variables, such as motility which is meaningful in terms of understanding how some sperm cells possess fertility advantages as compared with other cells. In the present research, initially there was a multivariate and clustering analysis used to assess sperm motility data from cryopreserved ram semen to identify subpopulations and compare the distribution of these clusters between rams with lesser and greater fertility. There were four classifications made of sperm subpopulations (clusters): CL1 fast/linear/progressive sperm; CL2 fast/non-linear sperm; CL3 very fast/linear sperm with vigorous beating and CL4 slow/non-linear sperm. Rams with greater fertility had a lesser proportion of sperm considered as “hyperactivated” (CL2) and a greater proportion of slow and non-linear sperm (CL4) than sperm of rams with lesser fertility. In addition, the effects were assessed for the capacity of seminal plasma (SP) and interacting SP proteins (iSPP) that were present during different seasons of the year to improve the distribution of sperm within subpopulations of semen from rams with lesser fertility. The iSPP and SP were obtained by artificial vagina (AV) and electroejaculation (EE) during breeding and non-breeding seasons and added to thawed semen. All the aggregates had a significant effect on the distribution of sperm subpopulations and effects differed among seasons of the year and depending on collection method used. Even though, future studies are needed to assess the contribution of each subpopulation on ram sperm fertility, it is important that a multivariate analysis be used to evaluate the effect of a treatment on sperm quality variables.S

Estudio de la microestructura de un cordón de soldadura de un acero P91 mediante microscopía electrónica de transmisión

En el presente trabajo se llevó a cabo la caracterización microestructural de un cordón de pasada simple de unacero 9Cr1MoVNb P91 obtenido por el proceso de soldadura semiautomática bajo protección gaseosa(FCAW), en la condición “as welding” mediante microscopía electrónica de transmisión.El acero P91 tiene una buena soldabilidad, pero las propiedades mecánicas de las uniones soldadas son inferioresa las del material base. La zona afectada por el calor (ZAC) de este tipo de aceros es de 4 mm lo quedificulta extraer réplicas y láminas delgadas para el estudio de las distintas microestructuras generadas encada sub-zona de la ZAC: ZAC de grano grueso (ZACGG), ZAC de grano fino (ZACGF) y ZAC intercrítica(ZACIC). No obstante, fue posible extraer réplicas de cada región para identificar a los precipitados y pormedio de la utilización de un haz de iones focalizados (FIB-SEM) se pudieron extraer láminas delgadas de unárea específica para caracterizar la microestructura de la matriz.Se caracterizaron los precipitados presentes en cada sub-zona de la ZAC y cómo la disolución del M23C6afecta a la matriz que lo rodea. A bajas temperaturas pico y bajas velocidades de calentamiento/enfriamientotales como las que caracterizan a las zonas de grano fino (ZACIC y ZACGF) se encontró austenita retenidaen contacto de los carburos M23C6 parcialmente disueltos. Por otra parte, en las zonas con más altas temperaturaspico y altas velocidades de calentamiento/enfriamiento (ZACGG y zona fundida) se encontraron películasfinas de austenita retenida en los ex bordes de grano austenítico y en los listones de martensita.Palabras clave: acero 9Cr1Mo, cordón de soldadura, microscopía electrónica

Parental support scale:New studies of internal structure and its relationship with socioeconomic variables

En la literatura se destacan numerosas variables que contribuyen a predecir el rendimiento académico. En tal sentido, el apoyo parentales considerado como una causa distal temprana del mismo. Sin embargo, existen resultados contradictorios en cuanto a su contribución, debido a los diferentes modos de operacionalizar dicho constructo. El objetivo del trabajo que se informa consistió en continuar los estudios de adaptación de la Escala de Apoyo Parental, iniciados por Aparicio y Cupani (2008). Específicamente se obtuvo evidencia de estructura interna y se exploró la contribución explicativa que realiza el apoyo parental en el rendimiento académico de los estudiantes, considerando el tipo de institución a la que asisten (pública o privada) y el nivel socioeconómico de sus padres. Los resultados indican que se logró replicar la estructura original de cuatro factores de la Escala de Apoyo Parental (Sehee & Hsiu-Zu, 2005). El estudio de consistencia interna indicó valores aceptables para tres de las cuatro escalas definidas teóricamente. Tanto en instituciones educativas públicas como privadas se observó que la percepción de apoyo parental se incrementa cuando el desempeño de los alumnos es bajo. Particularmente, la aspiración educacional de los padres y la supervisión que realizan sobre sus hijos contribuyeron a explicar el rendimiento académico de los estudiantes, en colegios públicos y privados, respectivamente. Con respecto al nivel socioeconómico, las familias de nivel medio-alto participan más activamente en la educación de sus hijos. Se discuten los resultados, se sugieren posibles estrategias de intervención y se destacan las limitaciones del estudio realizado.One of the main purposes in literature related to the field of education has been to identify the variables that contribute to predict academic performance. Particularly, parental support is considered as a distal factor that operates early over time (Byrnes & Miller, 2007). Nevertheless, studies have not identified how parental support triggers the students’ academic performance due to the different ways in which this construct has been operationalized. Since in our context it is available an adapted Scale of Parent Support (Aparicio & Cupani, 2008), the present work aims to continue the psychometric studies of the instrument. Specifically, a study of internal structure (confirmatory factor analysis) was developed and explanatory contributions to the academic performance of students were investigated, considering the socioeconomic status of parents and type of institution attended by the students. In this article, participants were 403 adolescents (male and female). They were attending to the third year of high school, in public and private schools of the city of Córdoba (Argentina), and they were between ages 13 to 17 (M = 14.27; SD = .93). The instruments were a questionnaire on socioeconomic status (Comisión de Enlace Institucional, 2006) and a Scale of Parental Support (Aparicio & Cupani, 2008). The students’ academic performance was operationalized by the average achieved in the Mathematics during the two semesters of the school year. The results replicated the original four-factor structure of the Scale of Parental Support (Sehee & Hsiu-Zu, 2005). The analysis showed satisfactory internal consistency values for three of the four scales theoretically defined (Communication: .82; Supervision: .77; Parent Educational Aspiration: .77, and Involvement: .61). Both in public and in private schools, it was observed that the perception of parental support increases when student’s performance is low. In particular, the educational aspirations of parents and the supervision of their children help to explain the academic performance of students in public and private schools, respectively. With regard to socioeconomic status, it was observed that the families of medium-high status participated more actively in the education of their children. Note that one of the limitations is the way in which the academic performance is measured in Argentina. Indeed, qualifications came from informal assessments designed by the teachers, so that they can be influenced by the particular guidelines of each institution and/or the educational framework of each teacher. Whereas the variables involved in student learning are numerous -among them, not only parental support perceived by students but other propensity factors (personality traits, skills, self-efficacy beliefs, for example) and even the characteristics of the institution-, the results of this study allow an approximation of how the support received by the parents, particularly the Monitoring and Aspiration, contribute to the academic performance of students. These observations have an impact on education because they might be useful to develop programs to maintain and enhance parental involvement in the education of their children. For example, it would be important to work with parents before the school year to encourage communication and participation in their children’s educational process.Fil: Contreras, Milena Lucia. Universidad Nacional de Córdoba. Facultad de Psicología. Centro de Investigaciones de la Facultad de Psicología; ArgentinaFil: Zalazar Jaime, Mauricio Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: de Mier, Mariela Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades; ArgentinaFil: Aparicio, Marín. Universidad Nacional de Córdoba. Facultad de Psicología. Centro de Investigaciones de la Facultad de Psicología; ArgentinaFil: Cupani, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro Interdisciplinario de Investigaciones en Psicología Matemática y Experimental Dr. Horacio J. A. Rimoldi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudio sobre Cultura y Sociedad. Centro de Investigaciones de la Facultad de Psicología - Grupo Vinculado CIPSI; Argentin

Aprendizajes y prácticas educativas en las actuales condiciones de época: COVID-19

“Esta obra colectiva es el resultado de una convocatoria a docentes, investigadores y profesionales del campo pedagógico a visibilizar procesos investigativos y prácticas educativas situadas en el marco de COVI-19. La misma se inscribe en el trabajo llevado a cabo por el equipo de Investigación responsable del Proyecto “Sentidos y significados acerca de aprender en las actuales condiciones de época: un estudio con docentes y estudiantes de la educación secundarias en la ciudad de Córdoba” de la Facultad de Filosofía y Humanidades. Universidad Nacional de Córdoba. El momento excepcional que estamos atravesando, pero que también nos atraviesa, ha modificado la percepción temporal a punto tal que habitamos un tiempo acelerado y angustiante que nos exige la producción de conocimiento provisorio. La presente publicación surge como un espacio para detenernos a documentar lo que nos acontece y, a su vez, como oportunidad para atesorar y resguardar las experiencias educativas que hemos construido, inventado y reinventando en este contexto. En ella encontrarán pluralidad de voces acerca de enseñar y aprender durante la pandemia. Este texto es una pausa para reflexionar sobre el hacer y las prácticas educativas por venir”.Fil: Beltramino, Lucia (comp.). Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Escuela de Archivología; Argentina

Heterologous recombinant protein with decapacitating activity prevents and reverts cryodamage in ram sperm: An emerging biotechnological tool for cryobiology

During the last decades fundamental and applied aspects of mammalian ram sperm cryopreservation have been increasingly explored by scientists and biotechnologists. Many works report modifications in the composition of the freezing extenders and explore the beneficial and detrimental effects of seminal plasma or seminal plasma components in cryopreservation. Seminal plasma is known to contain stabilizing proteins, thereby this is a good start point to study the maintenance of membrane stability based on the basic knowledge of sperm physiology. However, seminal plasma composition is variable among rams and also the introduction of exogenous seminal plasma or its fractions to commercial semen can be associated with the transmission of viral diseases. Our work shows that a mouse protein, called SPINK3 (Serine Protease Inhibitor Kazal type 3) with decapacitating activity interacts with heterologous ram sperm when it is produced as a recombinant molecule. By immunocytochemistry assays we demonstrate that this protein (naturally expressed by mouse seminal vesicle under androgenic control) binds to the apical portion of both fresh and frozen ram sperm, the same localization described in mouse homologous sperm. Furthermore, it significantly improves sperm progressive motility compared to non-treated samples when it is added to freezing extenders and to dilution media after thawing. On the contrary, addition of SPINK3 does not modify sperm viability. The percentage of sperm with intact acrosome after ionophore induction was also significantly higher in sperm frozen in the presence of SPINK3 compared to control samples and the addition of SPINK3 after thawing significantly reduced both induced and non induced acrosomal loss, indicating that heterologous SPINK3 might act as a calcium inhibitor transport as described in mouse. Based on our results SPINK3 may find a place as a desirable biotechnological tool to achieve a higher proportion of competent sperm to fertilize.EEA BalcarceFil: Zalazar, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Ledesma, Alba Verónica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Departamento de Producción Animal. Biotecnología de la Reproducción; ArgentinaFil: Hozbor, Federico Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Departamento de Producción Animal. Biotecnología de la Reproducción; ArgentinaFil: Cesari, Andreina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; Argentin

Recombinant SPINK3 improves ram sperm quality and in vitro fertility after cryopreservation

Capacitation-like changes affect sperm of several species, such as ram, reducing cell survival and fertilizing competence. Proteins from seminal plasma stabilize sperm plasma membranes, being an interesting focus to develop strategies for improving cryopreserved ram semen performance. To date, biotechnologies are focused to reduce damage in frozen-thawed ram spermatozoa through the addition of bioactives. Serine Protease Inhibitor Kazal-type 3 (SPINK3) is a little protein synthesized by mouse seminal vesicle and secreted to seminal plasma. While attached to the sperm, this protein binds to non-capacitated sperm and blocks calcium entry, avoiding a premature physiological capacitation and consequently, acrosome reaction. Due to these characteristics, SPINK3 has been proposed as a decapacitating factor. The aim of this work was to assess whether heterologous SPINK3 is able to protect ram sperm from the well-known cell damages produced by freezing/thawing and to understand the mechanisms by which it is acting. Sperm were supplemented with 13 μM SPINK3 before freezing in an egg yolk-based extender or after thawing and selection. Under both conditions, SPINK3 decreased intracellular calcium content (p < 0.05) and reduced the 25 kDa tyrosine phosphorylated protein demonstrating a decapacitating effect, although the addition of the protein before cryopreservation was not enough to improve other sperm parameters. However, the addition of SPINK3 post thawing was able to significantly ameliorate viability, motility, mitochondrial status and to avoid the increase of lipid peroxidation (p < 0.05). Moreover, sperm treated with SPINK3 was not only still capable to fertilize, but also improved it, as evidenced by an increase in the oocyte cleavage rate (p < 0.05) although, the embryo development and embryo quality were not affected. Our findings would contribute to develop a strategy for improving sperm quality by using decapacitating proteins. In fact, the outcomes of this work demonstrate that SPINK3 is able to reduce sperm cryo-injuries when is added after thawing, improving functionality and thus in vitro fertilization results.This research was supported by the National Agency for Scientific and Technological Promotion (ANPCyT, grant PICT-2015-3682 awarded to A.C), M.I.C was supported by Ministry of Economy and Competitiveness scholarship and the BeCAR program that facilitates the L.Z′ s stage in the UCLM, Spain.Peer reviewe

Study of the microstructure of a weld bead P91 steel by transmission electron microscopy

<p></p><p>ABSTRACT In the present work the microstructural characterization of a single-pass weld of 9Cr1MoVNb P91 steel performed by the flux-cored arc welding (FCAW) process in the “as welding” condition has been carried out by means of transmission electron microscopy. P91 steel offers a good weldability, but the mechanical properties of the welded joints are found to be inferior compared to the base metal. The heat affected zone (HAZ) of these types of steels is ~ 4 mm making it difficult to extract carbon replicas and thin foil to study the microstructure generated in each sub-zone of the ZAC: coarse grained ZAC (CGZAC), fine grained ZAC (FGZAC) and intercritical ZAC (ICZAC). Nev-ertheless, it was possible to extract replicas from each region to identify precipitates and using a focused ion beam (FIB-SEM), thin films could be extracted from a specific area to characterize the matrix microstructure. The precipitates present in each subzone of the ZAC were characterized as well as how the dissolution of M23C6 affects the matrix. At low peak temperatures and low heating / cooling rates such as those characterizing the fine grain zones (ICHAZ and FGHAZ) the M23C6 carbides were found to be partially dissolved and in contact with retained austenite. On the other hand, in the areas with the highest peak temperatures and high heating/cooling rates (CGHAZ and fusion zone) thin films of retained austenite were found on the austenitic grain boundaries and on the martensítica lath. On the other hand, in the areas with the highest peak temperatures and high heating / cooling rates (ZACGG and ZF) thin films of retained austenite on the austenitic grain edges and the martensite laths were found.</p><p></p

Bacterioruberin extracts from a genetically modified hyperpigmented Haloferax volcanii strain: antioxidant activity and bioactive properties on sperm cells

[Aims]: To examine the antioxidant activity of Bacterioruberin (Bctr)‐rich extracts isolated from a hyperpigmented, genetically modified Haloferax volcanii strain (HVLON 3) and to investigate the effect on cold‐sensitive ram sperm cells.[Methods and Results]: The strain HVLON 3 produces higher Bctr amounts than most haloarchaea (220 ± 13 mg g−1 DW ). HVLON 3‐Bctr extract has higher antioxidant activity than β‐carotene (threefold) as evaluated using 2,2 diphenyl‐1‐picrylhydrazyl combined with Electron Paramagnetic Resonance analysis (EC 50 4·5 × 10−5 mol l−1 vs 13·9 × 10−5 mol l−1 respectively). Different concentrations of HVLON 3‐Bctr extracts were assayed on ram sperm after freezing/thawing and physiologically relevant parameters were examined. Extracts containing 7 and 20 μ mol l−1 Bctr significantly improved cell viability (P < 0·0001), total and progressive motility (P < 0·0001) and sperm velocities (P = 0·0172 for curvilinear velocity VCL , P = 0·0268 for average path velocity VAP and P = 0·0181 for straight line velocity VSL ) and did not affect other parameters evaluated.[Conclusions]: HVLON 3 is an excellent source of natural microbial C50 carotenoids with applicability in Biotechnology, Biomedical and Veterinary fields. HVLON 3 Bctr extract improves the quality of cryopreserved ram sperm cells and could be applied to increase insemination yields.[Significance and Impact of the Study]: This study provides an insight on the bioactive properties of a bioproduct derived from haloarchaea (carotenoids) which are so far underexploited.This research was supported by the National Agency for Scientific and Technological Promotion (ANPCyT) grants PICT‐2015‐3682 and PICT‐2014‐1477 awarded to A.C. and R.D.C., respectively; UNMDP grants 15/E818, EXA819/17 and EXA823/17 awarded to M.S.C., A.C. and R.D.C, respectively.Peer reviewe