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Blastocystis sp. is a common intestinal microorganism. The a-L-fucosidase (ALFuc) is an enzyme long associated with the colonization of the gut microbiota. However, this enzyme has not been experimentally identified in Blastocystis cultures. The objective of the present study was to identify ALFuc in supernatants of axenic cultures of Blastocystis subtype (ST)1 ATCC-50177 and ATCC-50610 and to compare predicted ALFuc proteins of alfuc genes in sequenced STs1-3 isolates in human Blastocystis carriers. Excretion/secretion (Es/p) and cell lysate proteins were obtained by processing Blastocystis ATCC cultures and submitting them to SDS-PAGE and immunoblotting. In addition, 18 fecal samples from symptomatic Blastocystis human carriers were analyzed by sequencing of amplification products for subtyping. A complete identification of the alfuc gene and phylogenetic analysis were performed. Immunoblotting showed that the amplified band corresponding to ALFuc (~51 kDa) was recognized only in the ES/p. Furthermore, prediction analysis of ALFuc 3D structures revealed that the domain a-L-fucosidase and the GH29 family's catalytic sites were conserved; interestingly, the galactose-binding domain was recognized only in ST1 and ST2. The phylogenetic inferences of ALFuc showed that STs1-3 were clearly identifiable and grouped into specific clusters. Our results show, for the first time through experimental data that ALFuc is a secretion product of Blastocystis sp., which could have a relevant role during intestinal colonization; however, further studies are required to clarify this condition. Furthermore, the alfuc gene is a promising candidate for a phylogenetic marker, as it shows a conserved classification with the SSU-rDNA gene. [ABSTRACT FROM AUTHOR]

In‐house assays for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) by quantitative reverse‐transcription polymerase chain reaction (qRT‐PCR), are feasible alternatives, particularly in developing countries. Cycle threshold (Ct) values obtained by qRT‐PCR were compared with clinical and laboratory data from saliva of inpatients with COVID‐19 and asymptomatic health workers (AHW) were studied. Saliva specimens from 58 inpatients confirmed by qRT‐PCR for SARS‐CoV‐2 using nasopharyngeal specimens, and 105 AHW were studied by qRT‐PCR using three sets of primers for the N (N1, N2, and N3) gene of SARS‐CoV‐2, according to the CDC Diagnostic Panel protocol, showing a positivity of 88% for inpatients and 8% for AHW. Bivariate analysis revealed an association between Ct < 38.0 values for N2 and mechanical ventilation assistance among patients (p =.013). In addition, values of aspartate‐transaminase, lactate dehydrogenase, and ferritin showed significant correlations with Ct values of N1 and N3 genes in inpatients. Therefore, our results show that Ct values correlate with some relevant clinical data for inpatients with COVID‐19. [ABSTRACT FROM AUTHOR]

Abstract Taenia solium life cycle includes humans as definitive hosts and pigs as intermediate hosts. One of the measures to stop the life cycle of this parasite is by vaccination of pigs. In experiments performed in pigs with TSOL18 and TSOL45-1A, two recombinant T. solium proteins, 99.5% and 97.0% protection was induced, respectively. The purpose of this paper was to localize these antigens in all stages of the parasite (adult worms, oncospheres and cysticerci) by immunofluorescence, with the use of antibodies against TSOL18 and TSOL45-1A that were obtained from the pigs used in the vaccination experiment. Results show that TSOL18 and TSOL45-1A are expressed on the surface of T. solium oncospheres and not in tapeworms or cysticerci, indicating that they are stage-specific antigens. This, therefore, might explain the high level of protection these antigens induce against pig cysticercosis.

Abstract Viral population evolution dynamics of influenza A is crucial for surveillance and control. In this paper we analyzed viral genetic features during the recent pandemic caused by the new influenza human virus A H1N1, using a conventional population genetics approach based on 4689 hemagglutinin (HA) and neuraminidase (NA) sequences available in GenBank submitted between March and December of 2009. This analysis showed several relevant aspects: a) a scarce initial genetic variability within the viral isolates from some countries that increased along 2009 when influenza was dispersed around the world; b) a worldwide virus polarized behavior identified when comparing paired countries, low differentiation and high gene flow were found in some pairs and high differentiation and moderate or scarce gene flow in others, independently of their geographical closeness, c) lack of positive selection in HA and NA due to increase of the population size of virus variants, d) HA and NA variants spread in a few months all over the world being identified in the same countries in different months along 2009, and e) containment of viral variants in Mexico at the beginning of the outbreak, probably due to the control measures applied by the government.

The presence of anti-SARS-CoV-2 antibodies in serum indicates protection against the virus; however, although circulating antibodies control infection within the body, secretory IgA could provide better protection by acting as a primary barrier in containing the infection and therefore dispersing the virus. Our objective was to evaluate the seroconversion and titers of IgG, IgA and IgM against SARS-CoV-2 in Personnel Occupationally Exposed to SARS-CoV-2 (POE) in the Manuel Gea Gonzalez General Hospital. Using the ELISA technique, the antibody titers (IgG, IgA and IgM) against the synthetic peptides Spike (RBD, Arg319-Phe541) and Nucleocapsid (NCP, Met1-Ala419) were determined in the serum of three study groups: A) infected and vaccinated POE, b) uninfected and vaccinated POE and C) uninfected and unvaccinated POE. In addition, IgA was also detected in the saliva of group C. The percentage and titers of IgM, IgA and IgG versus NCP and RBD were similar in groups A and B (above 35 %), but not in group C, in the that IgG and IgA showed values below 10 % and no seroconversion of IgM versus RBD was observed. Regarding the detection of IgA in saliva, 35 % positivity was observed with RBD antigen and 25 % with NCP, higher percentages than in serum. Although RT-qPCR did not detect SARS-CoV-2 infection in Group C, antibodies against SARS-CoV-2 were detected; this could indicate that secretory IgA was excellent protection. [ABSTRACT FROM AUTHOR]