Efecto del pH y de la fuente de carbono sobre el crecimiento vegetativo de ustilago cynodontis (Pass.) Henn. en medio de cultivo sólido y líquido

El desarrollo de Ustilago cynodontis en cajas Petri con medio sólido en MM glucosa con pH 3-7 fue predominantemente micelial; crecimiento similar se observó en MM glicerol con pH de 3-5. El crecimiento micelial y de levadura se observó en cajas Petri en MM glucosa con pH 8 a las 96 h de incubación, y en MM glicerol con pH 5 a las 96 h y con pH 8 a las 24 h. La forma de levadura se observó en este último medio con pH 6-8 a las 48 y 96 h. En tubos cónicos en medio líquido con MM glucosa, el crecimiento fue micelial en pH 3 y 4, y en pH 5, 6, 7 y 8 a las 24 y 48 h. Crecimiento similar se observó en MM glicerol en los mismos pH e intervalos de tiempo. La forma de micelio y levadura se presentó en pH 5 y 6 a las 96 h en ambos medios y en pH 7 y 8 en MM glucosa a las 96 h, mientras, que la forma de levadura se presentó en pH 7 y 8 en MM glicerol a las 96 h

Culturable Airborne Fungi in Downtown Monterrey (Mexico) and Their Correlation with Air Pollution over a 12-Month Period

Biological and non-biological aerosols are always present. According to the World Health Organization (WHO), air pollution is responsible for seven million deaths every year. The dynamics of airborne fungi and their association with air pollutants over time show mixed results. In this study, we sampled 50 L of air daily for a period of 12 months (February 2022–January 2023) in downtown Monterrey, Mexico to evaluate the presence of culturable fungi. May, October, November, and December were the months with the highest concentration of fungi with a significant difference from the rest of the months. Cladosporium was the predominant fungus in the air for every month except for September. Aspergillus, Fusarium, and Penicillium followed Cladosporium as the genera with the highest concentration. PM10, PM2.5, and NO2 were the most abundant pollutants, with levels above the recommended guidelines in practically every month studied. Cladosporium was the only fungus showing an inverse correlation with PM10 and PM2.5 in February, April, and May. It also showed an inverse correlation with NO, NO2, and NOx in February, March, and April. Aspergillus, Alternaria, Fusarium, and Penicillium had mixed correlations with pollutants. Yeasts showed no correlation with PM10 or PM2.5 but showed inverse correlations with nitrogen-based pollutants

Acid pH Strategy Adaptation through <i>NRG1</i> in <i>Ustilago maydis</i>

The role of the Ustilago maydis putative homolog of the transcriptional repressor ScNRG1, previously described in Saccharomyces cerevisiae, Candida albicans and Cryptococcus neoformans, was analyzed by means of its mutation. In S. cerevisiae this gene regulates a set of stress-responsive genes, and in C. neoformans it is involved in pathogenesis. It was observed that the U. maydisNRG1 gene regulates several aspects of the cell response to acid pH, such as the production of mannosyl-erythritol lipids, inhibition of the expression of the siderophore cluster genes, filamentous growth, virulence and oxidative stress. A comparison of the gene expression pattern of the wild type strain versus the nrg1 mutant strain of the fungus, through RNA Seq analyses, showed that this transcriptional factor alters the expression of 368 genes when growing at acid pH (205 up-regulated, 163 down-regulated). The most relevant genes affected by NRG1 were those previously reported as the key ones for particular cellular stress responses, such as HOG1 for osmotic stress and RIM101 for alkaline pH. Four of the seven genes included WCO1 codifying PAS domain ( These has been shown as the key structural motif involved in protein-protein interactions of the circadian clock, and it is also a common motif found in signaling proteins, where it functions as a signaling sensor) domains sensors of blue light, two of the three previously reported to encode opsins, one vacuolar and non-pH-responsive, and another one whose role in the acid pH response was already known. It appears that all these light-reactive cell components are possibly involved in membrane potential equilibrium and as virulence sensors. Among previously described specific functions of this transcriptional regulator, it was found to be involved in glucose repression, metabolic adaptation to adverse conditions, cellular transport, cell rescue, defense and interaction with an acidic pH environment

Acid pH Strategy Adaptation through NRG1 in Ustilago maydis

The role of the Ustilago maydis putative homolog of the transcriptional repressor ScNRG1, previously described in Saccharomyces cerevisiae, Candida albicans and Cryptococcus neoformans, was analyzed by means of its mutation. In S. cerevisiae this gene regulates a set of stress-responsive genes, and in C. neoformans it is involved in pathogenesis. It was observed that the U. maydisNRG1 gene regulates several aspects of the cell response to acid pH, such as the production of mannosyl-erythritol lipids, inhibition of the expression of the siderophore cluster genes, filamentous growth, virulence and oxidative stress. A comparison of the gene expression pattern of the wild type strain versus the nrg1 mutant strain of the fungus, through RNA Seq analyses, showed that this transcriptional factor alters the expression of 368 genes when growing at acid pH (205 up-regulated, 163 down-regulated). The most relevant genes affected by NRG1 were those previously reported as the key ones for particular cellular stress responses, such as HOG1 for osmotic stress and RIM101 for alkaline pH. Four of the seven genes included WCO1 codifying PAS domain ( These has been shown as the key structural motif involved in protein-protein interactions of the circadian clock, and it is also a common motif found in signaling proteins, where it functions as a signaling sensor) domains sensors of blue light, two of the three previously reported to encode opsins, one vacuolar and non-pH-responsive, and another one whose role in the acid pH response was already known. It appears that all these light-reactive cell components are possibly involved in membrane potential equilibrium and as virulence sensors. Among previously described specific functions of this transcriptional regulator, it was found to be involved in glucose repression, metabolic adaptation to adverse conditions, cellular transport, cell rescue, defense and interaction with an acidic pH environment