INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y BIOTECNOLOGIA
Unidad Ejecutora - UE
Clear differences in metabolic and morphological adaptations of akinetes of two Nostocales living in different habitats
K. FORCHHAMMER; R. PEREZ; I. MALDENER; G. SALERNO
SOC GENERAL MICROBIOLOGY
Lugar: London; Año: 2016 vol. 162 p. 214 - 223
Akinetes are resting spore-like cells formed by some heterocyst-forming ﬁlamentouscyanobacteria for surviving long periods of unfavourable conditions. We studied thedevelopment of akinetes in two model strains of cyanobacterial cell differentiation, theplanktonic freshwater Anabaena variabilis ATCC 29413 and the terrestrial or symbioticNostoc punctiforme ATCC 29133, in response to low light and phosphate starvation. Thebest trigger of akinete differentiation of Anabaena variabilis was low light; that ofN. punctiforme was phosphate starvation. Light and electron microscopy revealed thatakinetes of both species differed from vegetative cells by their larger size, different cellmorphology and large number of intracellular granules. Anabaena variabilis akinetes had amultilayer envelope; those of N. punctiforme had a simpler envelope. During akinetedevelopment of Anabaena variabilis, the amount of the storage compounds cyanophycin andglycogen increased transiently, whereas in N. punctiforme, cyanophycin and lipid dropletsincreased transiently. Photosynthesis and respiration decreased during akinete differentiationin both species, and remained at a low level in mature akinetes. The clear differences in themetabolic and morphological adaptations of akinetes of the two species could be related totheir different lifestyles. The results pave the way for genetic and functional studies of akinetedifferentiation in these species.