Ficoflorística de cianobacterias en Laguna Chichancanab, Quintana Roo, México: Cianobacterias en Laguna Chichancanab, México

Background. Chichancanab Lake is one of the most important freshwater ecosystems located in the center of Yucatan peninsula (Mexico) as it is a primary hydrological ecoregion and habitat for endemic fauna species. However, its diversity of freshwater algae is poorly known, including cyanobacteria, a group that is of interest for its potential function as an indicator. Objective. Document the diversity of the cyanobacteria present in this site. Methods. Three samplings were carried out in different seasons of the year. The collection of freshwater algae was carried out directly. The samples were analyzed by light microscopy and diagnostic characteristics were collected depending on the taxa. Species were identified with specialized literature, in some cases the nomenclature was updated, and a review of its regional diversity was carried out. Results. In this study, 29 species of cyanobacteria belonging to different orders are reported, of which Synechococcales and the families Merismopediaceae (Synechococcales) and Oscillatoriaceae (Oscillatoriales) stand out. We report 18 new records for Quintana Roo, of which 11 are for Yucatan Peninsula: Synechococcus ambiguus, Eucapsis aphanocapsoides, E. parallelepippedon, Romeria hieroglyphica, Jaaginema subtilissimum, Komvophoron minimum, Planktolyngbya limnetica, Schizothrix tenuis, Spirulina nordstedtii, Phormidium californicum y P. lucidum. The ecological conditions of the site are similar to other tropical water bodies in different Caribbean countries and share at least 31.4% of morphospecies. Conclusions. A greater diversity of cyanobacteria than previously reported in the literature was found. This work intends to lay the foundations for the knowledge of freshwater algae in the lagoon and be a reference for future taxonomic, ecological, and applied works that start from this place.Antecedentes. La laguna Chichancanab es uno de los ecosistemas de agua dulce más importantes en el centro de la península de Yucatán (México) ya que es una ecorregión hidrológica primaria y hábitat de especies de fauna endémica. No obstante, se desconoce su diversidad de algas de aguas continentales, incluyendo a las cianobacterias, grupo que es de interés por su potencial función como indicador. Objetivo. Documentar la diversidad de las cianobacterias presentes en esta laguna. Métodos. Se realizaron tres muestreos en diferentes temporadas del año. La colecta de algas de agua dulce se realizó de forma directa, a la par que se tomaron variables fisicoquímicas. Las muestras se analizaron en microscopia óptica y se recabaron características diagnósticas dependiendo del taxón. Se identificaron a las especies con literatura especializada, en algunos casos se actualizó la nomenclatura, y se realizó una revisión sobre su diversidad regional. Resultados. En este estudio se reportan 29 especies de cianobacterias pertenecientes a diferentes órdenes, de los cuales destaca Synechococcales y las familias Merismopediaceae (Synechococcales) y Oscillatoriaceae (Oscillatoriales). Se reportan 18 nuevos registros para Quintana Roo, de los cuales 11 son para la Península de Yucatán: Synechococcus ambiguus, Eucapsis aphanocapsoides, E. parallelepippedon, Romeria hieroglyphica, Jaaginema subtilissimum, Komvophoron minimum, Planktolyngbya limnetica, Schizothrix tenuis, Spirulina nordstedtii, Phormidium californicum y P. lucidum. Las condiciones de la laguna son similares a la de otros cuerpos de agua tropicales en diferentes países del Caribe y comparten al menos un 31.4% de especies. Conclusiones. Se encontró una diversidad de cianobacterias mayor a lo reportado anteriormente en la literatura. Este trabajo pretende sentar las bases para el conocimiento de las algas de agua dulce en la laguna y ser referente a futuros trabajos taxonómicos, ecológicos y aplicados que partan de este lugar

Magnesium transporter 1 (MAGT1) deficiency causes selective defects in N-linked glycosylation and expression of immune-response genes

Magnesium transporter 1 (MAGT1) critically mediates magnesium homeostasis in eukaryotes and is highly-conserved across different evolutionary branches. In humans, loss– of–function mutations in the MAGT1 gene cause X-linked magnesium deficiency with Epstein-Barr virus (EBV) infection and neoplasia (XMEN), a disease that has a broad range of clinical and immunological consequences. We have previously shown that EBV susceptibility in XMEN is associated with defective expression of the antiviral natural-killer group 2 member D (NKG2D) protein and abnormal Mg transport. New evidence suggests that MAGT1 is the human homolog of the yeast OST3/ OST6 proteins that form an integral part of the N-linked glycosylation complex, although the exact contributions of these perturbations in the glycosylation pathway to disease pathogenesis are still unknown. Using MS-based glycoproteomics, along with CRISPR/Cas9-KO cell lines, natural killer cell-killing assays, and RNA-Seq experiments, we now demonstrate that humans lacking functional MAGT1 have a selective deficiency in both immune and nonimmune glycoproteins, and we identified several critical glycosylation defects in important immune-response proteins and in the expression of genes involved in immunity, particularly CD28. We show that MAGT1 function is partly interchangeable with that of the paralog protein tumor-suppressor candidate 3 (TUSC3) but that each protein has a different tissue distribution in humans. We observed that MAGT1-dependent glycosylation is sensitive to Mg levels and that reduced Mg impairs immune-cell function via the loss of specific glycoproteins. Our findings reveal that defects in protein glycosylation and gene expression underlie immune defects in an inherited disease due to MAGT1 deficiency

Defective glycosylation and multisystem abnormalities characterize the primary immunodeficiency XMEN disease

X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia (XMEN) disease are caused by deficiency of the magnesium transporter 1 (MAGT1) gene. We studied 23 patients with XMEN, 8 of whom were EBV naive. We observed lymphadenopathy (LAD), cytopenias, liver disease, cavum septum pellucidum (CSP), and increased CD4-CD8-B220-TCRαβ+ T cells (αβDNTs), in addition to the previously described features of an inverted CD4/CD8 ratio, CD4+ T lymphocytopenia, increased B cells, dysgammaglobulinemia, and decreased expression of the natural killer group 2, member D (NKG2D) receptor. EBV-associated B cell malignancies occurred frequently in EBV-infected patients. We studied patients with XMEN and patients with autoimmune lymphoproliferative syndrome (ALPS) by deep immunophenotyping (32 immune markers) using time-of-flight mass cytometry (CyTOF). Our analysis revealed that the abundance of 2 populations of naive B cells (CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4++CD10+CD38+ and CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4+CD10-CD38-) could differentially classify XMEN, ALPS, and healthy individuals. We also performed glycoproteomics analysis on T lymphocytes and show that XMEN disease is a congenital disorder of glycosylation that affects a restricted subset of glycoproteins. Transfection of MAGT1 mRNA enabled us to rescue proteins with defective glycosylation. Together, these data provide new clinical and pathophysiological foundations with important ramifications for the diagnosis and treatment of XMEN disease