POLYEXTREMOPHILE ACTINOBACTERIA: STUDY OF RESISTANCE TO COPPER BY SCANNING ELECTRON MICROSCOPY

ALVARADO, NATALIA NOELIA; SILVA MANCO, MARÍA JULIA; MARTINEZ, LUCIANO; ESQUIVEL, HERNÁN; FARÍAS, MARÍA EUGENIA; ALBARRACÍN, VIRGINIA HELENA

Biocell

Biocell

Año: 2020 vol. 45

0327-9545

POLYEXTREMOPHILE ACTINOBACTERIA: STUDY OF RESISTANCE TO COPPER BY SCANNING ELECTRON MICROSCOPYAlvarado N N (1,2), Silva Manco M J (3), Martínez L (1), Esquivel H (1), Farías M E (2), Albarracín V H (1,2)1. Centro Integral de Microscopia Electrónica (CIME), CCT-CONICET, UNT, Tucumán, Argentina. 2.Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), PROIMI, CCT-CONICET,Tucumán, Argentina. 3. Instituto de Investigación para el Desarrollo Sustentable de Ceja de Selva (INDES-CES) UniversidadToribio Rodrigues de Mendoza, Chachapoyas, Perú. E-mail: natalian.alvarado@gmail.com.The actinobacteria are a group of Gram-positive bacteria with a high content of G and C in their DNA and physiologically very diverse, they produce a great number of metabolites which are important in biotechnology. Due to this, emphasis is being placed on the isolation of these microorganisms from promising sources, such as the High-altitude Andean Lakes (HAAL), located in the region of the South American Central Andes, at a height of more than 3.500 masl. This place presents a microbiodiversity with unique mechanisms to adapt to extreme environmental factors, such as high salinity, dryness, UV radiation and heavy metals. In this piece of work, the morphological characteristics of polyextremophile bacteria were determined by Scanning Electron Microscopy after being subjected to copper stress. To this end, Nesterenkonia sp. Act20, isolated from the soil in Lake Socompa (3.750 m), was used. In addition, this was later compared to Nesterenkonia halotolerans DSMZ 15474, isolated from high saline soils in China. Resistance profiles were studied after being subjected to 3 mM CuSO4 in different times (24, 48, 72, 96 hours). For each of the times, were taken samples for scanning electron microscopy, they were fixed with Karnovsky fixative (p-formaldehyde 8% v / v, glutaraldehyde 25% v / v and phosphate buffer (pH = 7). The samples were dehydrated successively with increasing alcohol concentrations (30%, 50%,70%, 90%, and 100%) and acetone. The final dehydration was carried out with the critical point technique. Samples were mounted on scanning electron microscopy sample stubs and gold coated. Specimens were observed under vacuum using a Zeiss Supra 55VP (CarlZeissNTS GmbH, Germany) scanning electron microscope. The results demonstrate that the presence of heavy metals generate bacterial aggregation, the production of extracellular material and some morphological modifications such as increased surface roughness and apparent turgor. Furthermore, Nesterenkonia Act 20 presents a higher growth than Nesterenkonia halotolerans. These results contribute to reaffirm the biotechnological potentiality of the microorganisms isolated in LAPAs.