Cryptococcus spp. isolation from excreta of pigeons (Columba livia) in and around Monterrey, Mexico

The presence of Cryptococcus spp. has been reported in Mexico’s capital city; however, to our knowledge there are no reports of its presence in the state of Nuevo León located in northeast Mexico. This is presumed to be because the hot and dry climate in this region does not favor cryptococcal proliferation. This study confirmed the presence of C. neoformans and C. albidus in 20% (10/50) of randomly selected fecal samples of pigeons (Columba livia) in the Monterrey metropolitan area. The presence of this yeast in the state of Nuevo León is proof of its adaptation to the typically hot climate of the area and is consistent with recent reviews of cryptococcosis cases in several local hospitals. The two species were identified and characterized through microbiological tests and molecular identification by DNA extraction and PCR amplification of highly conserved 18S ribosomal DNA using ITS1 and ITS2 as target regions. The PCR products were sequenced and compared with those reported in GenBank

Standard Analytical Techniques and <em>de novo</em> Proposals for Successfull Soil Biodegradation Process Proposals

The contamination of water, air, and soil represent a serious problem worldwide. Therefore, it is a priority to reduce the levels of cytotoxic in the environment caused by human activities that generate chronic degenerative diseases. For example, soil contamination caused by oil and derivatives removed with biotechnological products based on biological systems of microorganisms with physiological and molecular mechanisms that allow them to carry out effective bioremediation processes, reducing the concentration of polluting hydrocarbons. The main obstacle is validating the biodegradation efficiency of chemical compounds by bacterial consortia; therefore, it is vital to adapt or develop analytical strategies to verify heavy-end reduction for each type of biological system used in remediation. This chapter describes the techniques and their adaptations for oil degradation and their derivatives promoted by microorganisms. As the limits of the methods vary within the parameters determined by international norms and laws, we compare conventional and new-generation proposals to adjust to probe biotechnological products based on consortia of biodiverse microorganisms that significantly degrade petroleum fractions

DIFFERENCES BETWEEN AGAR DILUTION, BROTH MACRODILUTION (CLSI M27-A3) AND E TEST (AB BIODISK) FOR FLUCONAZOLE RESISTANCE IN CLINICAL CANDIDA ALBICANS ISOLATES

Ensayos de susceptibilidad realizadas por dilución en agar (AD) se compararon con M27-A3 macrodilución de caldo (BMD) metodología (Clinical Laboratory Standards Institute y) y la prueba E (AB BIODISK) con el fin de determinar la viabilidad y la fiabilidad de dilución en agar como una prueba de unexpensive para ensayos de susceptibilidad a fluconazol (FLC) contra Candida albicans. Un total de 40 cepas fueron utilizados. Todos los aislamientos resultaron en un acuerdo para la DMO y la prueba de evaluación. 19 aislados mostraron concordancia entre los tres métodos. De los 21 resultados divergentes, 20 resultaron en una mayor MIC para la EA y 15 de ellos fueron ≥ 64 mg / ml. La densidad de células debido a un contacto proporcional de las células con el fármaco en el medio puede ser responsable de los resultados obtenidos y la divergencia de AD en comparación con las otras pruebas. AD no son capaces de sustituir ni la DMO ni prueba E, pero puede ser útil como una prueba de resistencia a la tensión preliminar para la clasificación de susceptibilidad en la investigación de laboratorio. Abstract Susceptibility assays performed by agar dilution (AD) were compared to M27-A3 broth macrodilution (BMD) methodology (Clinical Laboratory and Standards Institute) and E test (AB BIODISK) in order to determine the feasibility and reliability of agar dilution as an unexpensive test for fluconazole (FLC) susceptibility assays against Candida albicans. A total of 40 strains were used. All of the isolates resulted in agreement for BMD and E test. 19 isolates showed agreement between all three methods. Of the 21 divergent results, 20 resulted in higher MIC for AD and 15 of those were ≥64 μg/ml. Cell density due to proportional contact of cells with the drug in medium may be responsible for the results obtained and the divergence of AD compared to the other tests. AD can’t reliably substitute neither BMD nor E test, but it may be helpful as a preliminary resistance test for strain susceptibility classification in laboratory research. Palabras clave: Candida albicans, hongo, resitencia de droga

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

The RIM101/pacC Homologue from the Basidiomycete Ustilago maydis Is Functional in Multiple pH-Sensitive Phenomena

A homologue of the gene encoding the transcription factor Rim101 (PacC), involved in pH signal transduction in fungi, was identified in the pathogenic basidiomycete Ustilago maydis. The gene (RIM101) encodes a protein of 827 amino acid residues, which shows highest similarity to PacC proteins from Fusarium oxysporum and Aspergillus niger. The gene had the capacity to restore protease activity to rim101 mutants from Yarrowia lipolytica, confirming its homologous function, and was expressed at both acid and neutral pH. Null Δrim101 mutants were not affected in the in vitro pH-induced dimorphic transition, their growth rate, resistance to hypertonic sorbitol or KCl stress, and pathogenicity. However, similar to pacC (rim101) mutants in other fungi, they displayed a pleiotropic phenotype with alterations in morphogenesis, impairment in protease secretion, and increased sensitivity to Na(+) and Li(+) ions. Other phenotypic characteristics not previously reported in fungal pacC (rim101) mutants (morphological changes, increased sensitivity to lytic enzymes, and augmented polysaccharide secretion) were also observed in U. maydis mutants. All these modifications were alleviated by transformation with the wild-type gene, confirming that all were the result of mutation in RIM101. These data indicate that the Pal/Rim pathway is functional in U. maydis (and probably in other basidiomycetes) and plays complex roles in pH-sensing phenomena, as occurs in ascomycetes and deuteromycetes

Alkaliphilic/Alkali-Tolerant Fungi: Molecular, Biochemical, and Biotechnological Aspects

Biotechnologist interest in extremophile microorganisms has increased in recent years. Alkaliphilic and alkali-tolerant fungi that resist alkaline pH are among these. Alkaline environments, both terrestrial and aquatic, can be created by nature or by human activities. Aspergillus nidulans and Saccharomyces cerevisiae are the two eukaryotic organisms whose pH-dependent gene regulation has received the most study. In both biological models, the PacC transcription factor activates the Pal/Rim pathway through two successive proteolytic mechanisms. PacC is a repressor of acid-expressed genes and an activator of alkaline-expressed genes when it is in an active state. It appears, however, that these are not the only mechanisms associated with pH adaptations in alkali-tolerant fungi. These fungi produce enzymes that are resistant to harsh conditions, i.e., alkaline pH, and can be used in technological processes, such as in the textile, paper, detergent, food, pharmaceutical, and leather tanning industries, as well as in bioremediation of pollutants. Consequently, it is essential to understand how these fungi maintain intracellular homeostasis and the signaling pathways that activate the physiological mechanisms of alkali resistance in fungi

Promotion of Plant Growth in Arid Zones by Selected Trichoderma spp. Strains with Adaptation Plasticity to Alkaline pH

Trichoderma species are filamentous fungi that support plant health and confer improved growth, disease resistance, and abiotic stress tolerance. The objective of this study is to describe the physiological characteristics of the abundance and structure of Trichoderma model strains from arid zones and evaluate and describe their possible adaptation and modulation in alkaline pH. The presence of biotic factors such as phytopathogens forces farmers to take more actions such as using pesticides. In addition, factors such as the lack of water worldwide lead to losses in agricultural production. Therefore, the search for biocontrol microorganisms that support drought opens the door to the search for variations in the molecular mechanisms involved in these phenomena. In our case, we isolated 11 tested Trichoderma fungal strains from samples collected both from the rhizosphere and roots from two endemic plants. We probed their molecular markers to obtain their identity and assessed their resistance to alkaline conditions, as well as their response to mycoparasitism, plant growth promotion, and drought stress. The findings were worthy of being analyzed in depth. Three fungal taxa/species were grouped by phylogenetic/phenotypic characteristics; three T. harzianum strains showed outstanding capabilities to adapt to alkalinity stress. They also showed antagonistic activity against three phytopathogenic fungi. Additionally, we provided evidence of significant growth promotion in Sorghum bicolor seedlings under endemic agriculture conditions and a reduction in drought damage with Trichoderma infection. Finally, beneficial fungi adapted to specific ambient niches use various molecular mechanisms to survive and modulate their metabolism

Enzymatic Potential of Native Fungal Strains of Agave Residues

Abstract. Orexins or hypocretins are neurotransmitters produced by a small population of neurons in the lateral hypothalamus. This family of peptides modulates sleep-wake cycle, arousal and feeding behaviors; however, the mechanisms regulating their expression remain to be fully elucidated. There is an interest in defining the key molecular elements in orexin regulation, as these may serve to identify targets for generating novel therapies for sleep disorders, obesity and addiction. Our previous studies showed that the expression of orexin was decreased in mice carrying null-mutations of the transcription factor early B-cell factor 2 (ebf2) and that the promoter region of the prepro-orexin (Hcrt) gene contained two putative ebf-binding sites, termed olf‑1 sites. In the present study, a minimal promoter region of the murine Hcrt gene was identified, which was able to drive the expression of a luciferase reporter gene in the human 293 cell line. Deletion of the olf1-site proximal to the transcription start site of the Hcrt gene increased reporter gene expression, whereas deletion of the distal olf1-like site decreased its expression. The lentiviral transduction of murine transcription factor ebf2 cDNA into 293 cells increased the gene expression driven by this minimal Hcrt-gene promoter and an electrophoretic mobility shift assays demonstrated that the distal olf1-like sequence was a binding site for ebf2