Cell wall proteomics reveals a strong association of acta to the peptidoglycan promoting listeria monocytogenes invasiveness

Comunicaciones a congreso

G and P genotypes of rotavirus circulating among children with diarrhea in the Colombian northern coast

A study on the prevalence of rotavirus G and P genotypes was carried out based on 253 stool specimens obtained from children living in the Colombia northern coast region who were less than 3-years-old and who suffered from acute diarrhea. A previous study had detected the presence of rotavirus A in 90 (36.5%) of the 246 samples tested by enzyme immunoassay (EIA), and these strains were investigated in the present study. Of these, 50 strains yielded an RNA electropherotype, most of which (80.0%) had long profiles and 20.0% of which had short profiles. Genotyping of 84 positive samples indicated that 67.9% of the strains could be typed. G1 (57.9%), was the most predominant VP7 genotype, followed by G3 (21.1%), G9 (15.8%) and G2 (5.3%). Among the VP4 genotypes, P[4] (49.1%) was the most prevalent, followed by P[6] 36.4% and P[8] (14.5%). Neither G4 nor G8 nor P[9] types were detected. The most common G-P combinations were G3 P[4] (8.8%) and G9 P[6] (7.0%), followed by G1 P[4] and G1 P[8] (5.3% each). All G1 P[8] strains showed long RNA profiles, whereas G3 P[4] and G9 P[6] displayed both long and short patterns. Mixed infections involved 21.0% of strains. There was a marked diversity among strains collected, and novel strains, including G9, as well as other atypical combinations of G and P genotypes, such as G9 P[6] and G3 P[4], were found. [Int Microbiol 2004; 7(2):113-120

Mexican Validation of the MOS Questionnaire on Perceived Social Support in the Context of the COVID-19 Pandemic

Es un artículo científicoThe COVID-19 pandemic has had a very negative impact on people’s overall mental health and psychosocial well-being, but the study of available social support to cope with such an adverse situation has received hardly any attention. Objective: To examine the psychometric properties of the MOS Perceived Social Support Questionnaire among the Mexican population in the context of the COVID-19 pandemic. Method: Non-experimental cross-sectional study. A sociodemographic questionnaire and the Medical Outcomes Study were applied in a non-probabilistic sample. A total of 898 people from different regions in Mexico, 258 males and 640 females, participated in the study in the context of the COVID-19 pandemic. Results: The analysis yielded a bi-factor model with two factors, Emotional/informational support and Tangible support, with satisfactory goodness of fit indices. Reliability was adequate with a high hierarchical omega coefficient, as well as in the factors. Likewise, the H coefficient was adequate in the general factor and its dimensions. Conclusions: Results showed that the scale is a valid and reliable measure of perceived social support among the Mexican population

La interacción de procesos hidrológicos, químicos y microbiológicos en la formación de películas flotantes ricas en hierro en ambientes acuáticos de pH circumneutro

17 páginas.-- 3 figuras.-- 4 tablas.-- 53 referencias.-- Postprint (Versión editorial)[EN]: The direct contribution of microbial activity to the formation of iron-oxide minerals is difficult to prove in wetlands due to the high reactivity of solid iron phases with different compounds and the variety of redox processes that may occur at each oxic-anoxic boundary. Here, we propose an explanation for the formation of iron-oxide films in wetlands and groundwater seepage areas fed by sandy aquifers based on the interaction of hydrological, chemical and microbiological processes under circumneutral conditions. The presence of a floating iron-oxide film was found to create a boundary at the air-water interface that maintains a suboxic and slightly acidic environment below the film compared with the environments obtained in other free-film wetland areas. The water trapped below this film had an average pH of 6.1, was particularly poor in O2, HCO–3, Na+, Ca2+, Mg2+, K+, and Tot-S, and has high concentrations of Tot-P, Tot-Fe, NH+4 and Zn. The formation of a floating iron-oxide film was reproduced under anaerobic conditions after progressive enrichment through the incubation of natural sediment samples in the laboratory. Heterotrophic bacteria belonging to the genus Enterobacter were the dominant bacteria in the enrichments that resulted in the formation of a floating iron-oxide film. The X-ray diffraction patterns showed that the presence of two-line ferrihydrite was common to the iron-oxide films collected in both the natural environment and the laboratory cultures, whereas other iron-oxides (goethite and low-crystalline lepidocrocite) were observed only in the natural environment. This study highlights the role of ubiquitous bacteria, which are generally considered unimportant participants in iron-transformation processes in the environment, and the contribution of both biological and non-biological processes to iron oxidation in natural systems under circumneutral conditions.[ES]: En los humedales, es difícil probar que la actividad microbiana sea la responsable de la formación de óxido de hierro mineral debido, tanto a la gran reactividad del hierro en fase sólida con diferentes sustancias, como a la variedad de procesos redox que pueden ocurrir en cada interfase óxica-anóxica. El presente trabajo propone una explicación, basada en la interacción de procesos hidrológicos, químicos y microbiológicos en condiciones circumneutras, para explicar la formación de un film de óxido de hierro en humedales y manaderos donde aflora agua subterránea proveniente de acuíferos de arenas silíceas. Además, la presencia de un film de óxido de hierro que flota sobre la interfase agua-aire genera condiciones subóxicas y ligeramente ácidas en el agua que queda atrapada debajo, y que son muy distintas a otras zonas libres de film en el mismo humedal. Este agua atrapada bajo el film se caracterizó por presentar un pH medio de 6.1, una menor concentración de O2, HCO–3, Na+, Ca2+, Mg2+, K+, y S total, pero una mayor riqueza en P total, Fe total, NH+4 y Zn. La formación de un film flotante de óxido de hierro se reprodujo en el laboratorio, en condiciones anaeróbicas, tras el enriquecimiento progresivo de las muestras del sedimento natural que habían sido incubadas. En dichos enriquecimientos, donde se produjeron films flotantes de óxido de hierro, la bacteria dominante perteneció al género Enterobacter. Mediante difracción por rayos X, se encontró ferrihidrita con estructura en doble cadena, tanto en el film de muestras naturales como de cultivos de laboratorio. Además se encontraron otros tipos de óxidos minerales (goetita y lepidocrocita de pobre cristalización) sólo en las muestras naturales de film. El presente estudio muestra la relevancia de bacterias ubicuas, hasta ahora consideradas sin importancia en procesos naturales de transformación del hierro, y la participación tanto de procesos bióticos como abióticos en la oxidación del hierro en sistemas naturales sometidos a condiciones circumneutras.We are grateful to Han Golterman for his support and suggestions. We thank Lotte Fleskens and Christien van der Zwart for collaborating with the sediment collection and P-fractionation at the laboratory. This study was partially supported by the Spanish Ministry of Education and Science (CGL2004-03927-C02-01/BOS)Peer reviewe

The essential peptidoglycan glycosyltransferase MurG forms a complex with proteins involved in lateral envelope growth as well as with proteins involved in cell division in Escherichia coli

In Escherichia coli many enzymes including MurG are directly involved in the synthesis and assembly of peptidoglycan. MurG is an essential glycosyltransferase catalysing the last intracellular step of peptidoglycan synthesis. To elucidate its role during elongation and division events, localization of MurG using immunofluorescence microscopy was performed. MurG exhibited a random distribution in the cell envelope with a relatively higher intensity at the division site. This mid-cell localization was dependent on the presence of a mature divisome. Its localization in the lateral cell wall appeared to require the presence of MreCD. This could be indicative of a potential interaction between MurG and other proteins. Investigating this by immunoprecipitation revealed the association of MurG with MreB and MraY in the same protein complex. In view of this, the loss of rod shape of ΔmreBCD strain could be ascribed to the loss of MurG membrane localization. Consequently, this could prevent the localized supply of the lipid II precursor to the peptidoglycan synthesizing machinery involved in cell elongation. It is postulated that the involvement of MurG in the peptidoglycan synthesis concurs with two complexes, one implicated in cell elongation and the other in division. A model representing the first complex is proposed

On cytoadhesion of Plasmodium vivax: raison d'être?

It is generally accepted that Plasmodium vivax, the most widely distributed human malaria parasite, causes mild disease and that this species does not sequester in the deep capillaries of internal organs. Recent evidence, however, has demonstrated that there is severe disease, sometimes resulting in death, exclusively associated with P. vivax and that P. vivax-infected reticulocytes are able to cytoadhere in vitro to different endothelial cells and placental cryosections. Here, we review the scarce and preliminary data on cytoadherence in P. vivax, reinforcing the importance of this phenomenon in this species and highlighting the avenues that it opens for our understanding of the pathology of this neglected human malaria parasite.798

Morphological and Transcriptional Changes in Human Bone Marrow During Natural Plasmodium vivax Malaria Infections.

--- - Label: BACKGROUND NlmCategory: BACKGROUND content: The presence of Plasmodium vivax malaria parasites in the human bone marrow (BM) is still controversial. However, recent data from a clinical case and experimental infections in splenectomized nonhuman primates unequivocally demonstrated the presence of parasites in this tissue. - Label: METHODS NlmCategory: METHODS content: In the current study, we analyzed BM aspirates of 7 patients during the acute attack and 42 days after drug treatment. RNA extracted from CD71+ cell suspensions was used for sequencing and transcriptomic analysis. - Label: RESULTS NlmCategory: RESULTS content: We demonstrated the presence of parasites in all patients during acute infections. To provide further insights, we purified CD71+ BM cells and demonstrated dyserythropoiesis and inefficient erythropoiesis in all patients. In addition, RNA sequencing from 3 patients showed that genes related to erythroid maturation were down-regulated during acute infections, whereas immune response genes were up-regulated. - Label: CONCLUSIONS NlmCategory: CONCLUSIONS content: This study thus shows that during P. vivax infections, parasites are always present in the BM and that such infections induced dyserythropoiesis and ineffective erythropoiesis. Moreover, infections induce transcriptional changes associated with such altered erythropoietic response, thus highlighting the importance of this hidden niche during natural infections

Plasmodium vivax gametocytes in the bone marrow of an acute malaria patient and changes in the erythroid miRNA profile

Plasmodium vivax is the most widely distributed human malaria parasite and responsible for large amounts of disease and burden [1]. The presence of P. vivax in the bone marrow was first noticed in the late 19th century [2], and examinations of sternal bone marrow aspirates were performed as an accessory to examinations of peripheral blood in malaria, including P. vivax [3]. Since then, little progress has been made in studying P. vivax infections in this tissue. One report explored accumulation of dyserythropoietic cells in anaemic infected patients [4]. In addition, two case studies reported P. vivax infections after autologous bone marrow transplantation [5][6], and a third one documented an accidental P. vivax infection due to bone marrow transplantation between a malaria-infected donor and a malaria-free receptor [7]. In Brazil, one patient with persistent thrombocytopaenia and an enlarged spleen was diagnosed with chronic P. vivax malaria after the finding of schizonts in the bone marrow aspirate [8]. In all these reports and case studies, however, parasite loads and life stages found in the bone marrow were not investigated, and no molecular tools were available to rule out mixed infections or to characterize specific parasite stages