Cryopreservation of the Microalgae Scenedesmus sp.

Each phytoplankton species presents a different behavior and tolerance to the cryopreservation process. Therefore, in a species-specific protocol, it is essential to ensure both growth and post-thawing cell viability. In this study, we explored the effect of cryopreservation of Scenedesmus sp. with two cryoprotectants, dimethyl sulfoxide (DMSO) and methanol (MET), at 5% and 10% inclusion for each. In the control treatment, the microalgae were not exposed to cryoprotective agents (Control). Three post-thawing cell viability criteria were used: no cell damage (NCD), cell damage (CD), and marked lesions (LM), and mitochondrial and cell membrane damage was evaluated by flow cytometry. The study was a 2 × 2 factorial design, with five replications by treatments, population growth, and cell damage evaluated from the fifth day after thawing. On the fifth day, the highest percentage of NCD was observed when the microalgae were cryopreserved with DMSO 5% (50%); Regarding the control group, it showed 0% NCD. Flow cytometry analysis reveals minor damage at the membrane and mitochondria (9-10.7%) when DMSO is used at both inclusion percentages (5-10%) after thawing. In the exponential phase, the highest growth rates, doubling time, and yield was observed in cryopreserved cells with MET 5%. The results suggest that DMSO 5% is an ideal treatment for cryopreserving microalgae Scenedesmus sp.

Identificación presuntiva de Cryptococcus gattii aislado de Terminalia catappa en Montería, Córdoba, Colombia / Presumptive identification of Cryptococcus gattii isolated from Terminalia catappa in Montería city, Córdoba, Colombia

Introducción: los miembros del complejo Cryptococcus neoformans, son la causa de criptococosis en humanos y animales. La infección en humanos es adquirida por la inhalación de los propágulos presentes en el ambiente, por esta razón es de gran importancia el estudio de su hábitat. Objetivo: determinar la relación ecológica de Cryptococcus gattii con árboles de Terminalia catappa presentes en la zona urbana de la ciudad de Montería, Colombia. Métodos: se seleccionaron 163 árboles de Terminalia catappa de los cuales se tomaron muestras de corteza, hojas, flores, fruto y suelo circundante. El aislamiento se realizó utilizando el medio de agar semillas de Guizotia abyssinica, la identificación se hizo mediante pruebas morfológicas y fisiológicas y la variedad se determinó con las pruebas de L-canavanina-glicina-azul de bromotimol (CGB), D-prolina y D-triptofano. Resultados: se obtuvieron 9,050 UFC/g con características de Cryptococcus spp. De ellas, 5,795 UFC/g correspondieron presuntivamente a Cryptococcus gattii. El mayor porcentaje de aislamientos se encontró en flores, seguido por corteza y fruto, con tamaños celulares y capsulares pequeños. Estos aislamientos fueron más frecuentes en el sur de la ciudad, seguido por la zona centro y en menor porcentaje por la zona norte. Conclusiones: los hallazgos muestran una estrecha relación entre Cryptococcus gattii y Terminalia catappa. Este estudio es el primero que se hace en la ciudad de Montería. Los resultados brindan información valiosa para la comprensión y el análisis sobre la epidemiología de la criptococosis en la ciudad de Montería, Colombia.

Introduction: the members of the Cryptococcus neoformans species complex are responsible for cryptococcosis in animals and humans. Human infection is thought to be acquired by inhalation of airborne propagules from an environmental source; therefore it is greatly important to study their habitat. Objective: to determine the ecological relationship of Cryptococcus gattii with Terminalia catappa trees present in urban areas of Montería city in Colombia. Methods: a total of 163 Terminalia catappa trees were selected; some samples were taken from the bark, the leaves, the flowers, the fruits of these trees and from the surrounding soil. The yeast was isolated using the Guizotia abyssinica seed agar medium; it was identified thanks to biochemical and morphologic tests whereas the right variety was determined by L-canavanine-glycine- bromothymol blue (CGB), D-proline and D-tryptophan tests. Results: there was obtained 9.050 CFU/g isolate of Cryptococcus spp., 5.795 CFU/g of which were presumptively identified as Cryptococcus gattii. The highest percentage of isolates was found in flowers, followed by bark and fruits, presenting small cellular and capsular sizes. These isolates were more frequent in the south of the city, followed by the center zone and the lowest percentage in the northern zone. Conclusions: these findings confirmed the close relationship of Cryptococcus gattii and Terminalia catappa, being this the first study conducted in Montería city. These results give us meaningful information for understanding and analyzing the epidemiology of cryptococcosis in Monteria city, Colombia.

[Presumptive identification of Cryptococcus gattii isolated from Terminalia catappa in Montería city, Córdoba, Colombia]. / Identificación presuntiva de Cryptococcus gattii aislado de Terminalia catappa en Montería, Córdoba, Colombia.

INTRODUCTION: the members of the Cryptococcus neoformans species complex are responsible for cryptococcosis in animals and humans. Human infection is thought to be acquired by inhalation of airborne propagules from an environmental source; therefore it is greatly important to study their habitat. OBJECTIVE: to determine the ecological relationship of Cryptococcus gattii with Terminalia catappa trees present in urban areas of Montería city in Colombia. METHODS: a total of 163 Terminalia catappa trees were selected; some samples were taken from the bark, the leaves, the flowers, the fruits of these trees and from the surrounding soil. The yeast was isolated using the Guizotia abyssinica seed agar medium; it was identified thanks to biochemical and morphologic tests whereas the right variety was determined by L-canavanine-glycine-bromothymol blue (CGB), D-proline and D-tryptophan tests. RESULTS: there was obtained 9.050 CFU/g isolate of Cryptococcus spp., 5.795 CFU/g of which were presumptively identified as Cryptococcus gattii. The highest percentage of isolates was found in flowers, followed by bark and fruits, presenting small cellular and capsular sizes. These isolates were more frequent in the south of the city, followed by the center zone and the lowest percentage in the northern zone. CONCLUSIONS: these findings confirmed the close relationship of Cryptococcus gattii and Terminalia catappa, being this the first study conducted in Monteria city. These results give us meaningful information for understanding and analyzing the epidemiology of cryptococcosis in Monteria city, Colombia.