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Here, we report for the first time the circulation of dengue virus type 1 (DENV-1) belonging to the lineage IV of genotype V (African American genotype) based on phylogenetic analysis of nucleotide sequences from 10 DENV-1-positive samples obtained in Mexico between 2012 and 2014. Our data revealed that the lineages III and IV of DENV-1 genotype V were found circulating during the same period, probably explaining the rise in the number of cases of severe dengue during that period.

The axolotl (Ambystoma mexicanum) is the vertebrate model system with the highest regeneration capacity. Experimental tools established over the past 100 years have been fundamental to start unraveling the cellular and molecular basis of tissue and limb regeneration. In the absence of a reference genome for the Axolotl, transcriptomic analysis become fundamental to understand the genetic basis of regeneration. Here we present one of the most diverse transcriptomic data sets for Axolotl by profiling coding and non-coding RNAs from diverse tissues. We reconstructed a population of 115,906 putative protein coding mRNAs as full ORFs (including isoforms). We also identified 352 conserved miRNAs and 297 novel putative mature miRNAs. Systematic enrichment analysis of gene expression allowed us to identify tissue-specific protein-coding transcripts. We also found putative novel and conserved microRNAs which potentially target mRNAs which are reported as important disease candidates in heart and liver.

Mercury-resistant Aeromonas strains isolated from diarrhea were studied. Resistance occurs via mercuric ion reduction but merA and merR genes were only detected in some strains using PCR and dot hybridization. Results indicate a high variability in mer operons in Aeromonas. To our knowledge, this is the first report of mercury-resistant clinical Aeromonas strains.

Fungal pathogens have developed strategies, involving genes expression that favors their persistence and multiplication in the host. The absence of molecules encoded by these genes could interfere with the growth and death of these fungi. In the past, a coactivator protein coding gene (Hcp100) of the fungus Histoplasma capsulatum was reported, which is overexpressed after 1h of contact between fungal yeast-cells and murine macrophages. The product of this gene, a protein of 100 kDa (Hcp100) of H. capsulatum, is probably a regulatory protein involved in the processes required for fungal adaptation and its survival in the intracellular hostile conditions of the macrophages. A 210-bp fragment of the Hcp100 marker has proved to be an excellent tool for H. capsulatum molecular detection in clinical samples. The potential use of this gene as a therapeutic target in Plasmodium falciparum has been explored through the inhibition of both, the gene and the protein p100 of the parasite, by blocking its growth.Based on the above mentioned antecedents, we believe that the Hcp100 has an important role in the development and maintenance of the H. capsulatum yeast cells within macrophages.To study the probable function of Hcp100 in the yeast-phase of this fungal pathogen is relevant to understand its activity and to propose it as a therapeutic target for histoplasmosis treatment.

This study investigated the possible in vivo transfer of plasmid pRAS1 between Aeromonas salmonicida and A. hydrophila inhabiting two different organs of Cyprinus carpio L. To distinguish transconjugants from naturally occurring antibiotic resistant bacteria, twelve luminescent transposon-tagged A. hydrophila strains using mini Tn5luxCDABEKm2 transposon were generated. In conjugal transfer experiments, fish were conditioned with the donor bacteria and subsequently immersed in water containing the recipient strain. Bacteria were recovered from gills and intestines and isolated by growth on selective plates. Transconjugants were identified by their resistance to the pRAS1 encoded antimicrobials and by light emission. In vivo transfer frequencies ranged between 10(-3) and 10(-6) and were somewhat lower in intestines, compared to gills. Transfer frequencies were also smaller relative to those obtained in vitro. The minimal amount of donor and recipient bacteria needed to yield detectable transconjugants in vivo was 1 x 10(4) CFU mL(-1). Implications of this plasmid transfer in natural settings and its possible consequences to human health are discussed.

A nonimmune library, containing single chain variable fragments (scFv) of immunoglobulin human genes displayed on the surface of M13 filamentous phages, was used to recognize molecules exposed on Histoplasma capsulatum yeasts' surface, during their growth in synthetic medium. The scFv clones were checked in their consistency by Dot-ELISA using HRP/anti-M13 conjugate, and they were tested to recognize molecules on H. Capsulatum yeasts' surface by ELISA in plates. Three out of 80 scFv cones (C2, C6, and C52) reacted consistently with H. capsulatum molecules, and they recognized molecules from both H. capsulatum morphologic phases. However, C6 and C52 clones reacted better with molecules on the surface of whole yeasts, with molecules from the yeasts' cell-wall extract, and with molecules released to the supernatant of the yeast culture. Mycelial supernatants from other fungi, as well as from a Mycobacterium filtrate, were not recongnized by scFv phage monoclones. Monoclones C2, C6, and C52 recognized yeast molecules irrespective of the H. capsulatum strains used; the C6 clone revealed a specific immunohistochemistry reaction when tested against homologous and heterologous fungal infected tissues. The scFv clones isolated will be a useful toll to define the role of their target molecules in the host–parasite relationship of histoplasmosis.

Background Breast cancer is one of the most frequent causes of death in Mexican women over 35 years of age. At molecular level, changes in many genetic networks have been reported as associated with this neoplasia. To analyze these changes, we determined gene expression profiles of tumors from Mexican women with breast cancer at different stages and compared these with those of normal breast tissue samples. Methods 32P-radiolabeled cDNA was synthesized by reverse transcription of mRNA from fresh sporadic breast tumor biopsies, as well as normal breast tissue. cDNA probes were hybridized to microarrays and expression levels registered using a phosphorimager. Expression levels of some genes were validated by real time RT-PCR and immunohistochemical assays. Results We identified two subgroups of tumors according to their expression profiles, probably related with cancer progression. Ten genes, unexpressed in normal tissue, were turned on in some tumors. We found consistent high expression of Bik gene in 14/15 tumors with predominant cytoplasmic distribution. Conclusion Recently, the product of the Bik gene has been associated with tumoral reversion in different neoplasic cell lines, and was proposed as therapy to induce apoptosis in cancers, including breast tumors. Even though a relationship among genes, for example those from a particular pathway, can be observed through microarrays, this relationship might not be sufficient to assign a definitive role to Bik in development and progression of the neoplasia. The findings herein reported deserve further investigation.

Axenically grown Entamoeba histolytica produces a pentapeptide (Met-Gln-Cys-Asn-Ser) with anti-inflammatory properties that, among others, inhibits the in vitro and in vivo locomotion of human monocytes, sparing polymorphonuclear leucocytes from this effect [hence the name originally given. Monocyte Locomotion Inhibitory Factor (MLIF)]. A synthetic construct of this peptide displays the same effects as the native material. We now added MLIF to resting and PMA-stimulated cells of a human monocyte cell line and measured the effect upon mRNA and protein expression of pro-inflammatory chemokines (RANTES, IP-10, MIP-1alpha, MIP-1beta, MCP-1, IL-8, I-309 and lymphotactin) and the shared CC receptor repertoire. The constitutive expression of these chemokines and the CC receptors was unaffected, whereas induced expression of MIP-1alpha, MIP-1beta, and I-309, and that of the CCR1 receptor--all involved in monocyte chemotaxis--was significantly inhibited by MLIF. This suggests that the inhibition of monocyte functions by MLIF may not only be exerted directly on these cells, but also--and perhaps foremost--through a conglomerate down-regulation of endogenous pro-inflammatory chemokines.

Background Although sophisticated methodologies are available, the use of endpoint polymerase chain reaction (PCR) to detect 16S rDNA genes remains a good approach for estimating the incidence and prevalence of specific infections and for monitoring infections. Considering the importance of the early diagnosis of sexually transmitted infections (STIs), the development of a sensitive and affordable method for identifying pathogens in clinical samples is needed. Highly specific and efficient primers for a multiplex polymerase chain reaction (m-PCR) system were designed in silico to detect the 16S rDNA genes of four bacteria that cause genital infections, and the PCR method was developed. Methods The Genosensor Probe Designer (GPD) (version 1.0a) software was initially used to design highly specific and efficient primers for in-house m-PCR. Single-locus PCR reactions were performed and standardised, and then primers for each locus in turn were added individually in subsequent amplifications until m-PCR was achieved. Amplicons of the expected size were obtained from each of the four bacterial gene fragments. Finally, the analytical specificity and limits of detection were tested. Results Because they did not amplify any product from non-STI tested species, the primers were specific. The detection limits for the Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum primer sets were 5.12 × 105, 3.9 × 103, 61.19 × 106 and 6.37 × 105 copies of a DNA template, respectively. Conclusions The methodology designed and standardised here could be applied satisfactorily for the simultaneous or individual detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum. This method is at least as efficient as other previously described methods; however, this method is more affordable for low-income countries.

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the sacroiliac joints and vertebral column of unknown aetiology, but strongly related to the presence of the HLA-B27 antigen. The participation of bacterial infections as triggering factors have also been suggested. We have associated the 60 kDa heat shock protein of Klebsiella pneumoniae (HSP60Kp) with AS since we have previously demonstrated that most of the patients have IgG antibodies and active T cells that recognize preferentially this protein, but we have not yet identified the epitopes involved in the recognition. In order to know the amino acid sequence of HSP60Kp, and to be able to analyse in the future the relevant epitopes, we amplified by PCR and cloned the gene coding for this protein into the Sma I site of pUC19. The nucleotide sequence of the gene was obtained by the Sanger method using both manual and automatic techniques. Amino acid sequence of the HSP60Kp was deduced by translating the nucleotide sequence of the gene. The antigenic analysis of this sequence was compared to the antigenic analysis of the reported sequences of Escherichia coli GroEL and Yersinia enterocolitica HSP60. Using a software to predict HLA class I motifs, the nonapeptide (KRGIDKAVL) residues 117-125 of HSP60Kp showed a much higher affinity for HLA-B27 than the similar nonapeptide of E. coli GroEL and Y. enterocolitica HSP60. The only difference between the three peptides was in position nine. This finding could explain the association of AS only with the HSP60 of Klebsiella pneumoniae . On the other hand, hydrophilicity analysis, which indicates B cell epitopes, showed three similar strongly antigenic regions in the three proteins.

Purpose: HLA class II, p-36 protein, heat shock protein and retinal antigens have been associated with pars planitis (PP), but their participation in the development of the disease are unknown. A search for new molecules related to PP is necessary. This work focused on the identification of peptides recognized by PP patient sera using the phage display method. Methods: Sera of PP patients were used to isolate peptides fused to M13-phage pIII protein. The response of PP and healthy sera to peptides was determined by ELISA. PCR amplification and sequencing of peptide-encoding fragments from clones with high recognition by PP sera were used to characterize displayed peptides. Results: One hundred clones were randomly selected from a phage display library after three panning rounds using serum proteins from a PP patient. The immunologic response level of 100 clones selected were determined with a major number of patients, it was found that one clone was recognized stronger in PP patients sera than in healthy sera (PP vs. healthy; P