Unlike linear electron transport, which produces both ATP and NADPH, cyclic electron transport is involved only in ATP production. In H. pluvialis cells, 90% of astaxanthin is attached with one or two fatty acids, forming astaxanthin mono- and diesters. Since NADPH is required for synthesis of astaxanthin and fatty acids, the reducing power of palmella cells may not be sufficient to produce amounts of astaxanthin esters equivalent to those produced by motile cells under the same circumstances. Therefore, our future efforts will explore how to enhance NADPH GSI-IX production in palmella cells as well as how to increase the levels of astaxanthin biosynthetic enzymes through physical or genetic manipulations. Additionally, we will investigate biotic and abiotic factors that stimulate the development of protective mechanisms in palmella cells. In most countries, the incidence and prevalence of chronic kidney disease have been increasing over the years mainly due to the aging population and the presence of diabetic nephropathy. It is well established that acute kidney injury after ischemia/reperfusion injury is a major cause of AKI. IRI physiology involves a complex interaction among vascular, tubular and inflammatory factors followed by a repair process that can restore function and epithelial differentiation or result in CKD with progressive development of fibrosis. It has been shown that the mortality of patients with CKD is directly related to renal function associated with cardiovascular diseases and infections. However, such traditional risks explain only about half of mortality and various studies are being directed to non-traditional risk factors, such as vitamin D. Vitamin D is a circulating hormone in the body indispensable for mineral homeostasis and responsible for kidney protection and regulation of several physiological activities as well. Thus, vitamin D deficiency or insufficiency can accelerate the progression of kidney disease. The biologically active form of vitamin D is produced in the kidney by mitochondria of the renal proximal convoluted tubules, where 1a-hydroxylase converts 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D3 or calcitriol. The classical 1,25 2D3 pathway requires the nuclear vitamin D receptor, which is a transcription factor for 1,25 2 D3 target genes. The renal conversion of vitamin D into biologically active form is tightly regulated by several factors, including parathormone, phosphorus levels and fibroblast growth factor 23. FGF-23 is a phosphatonin produced by osteocytes which promotes renal phosphate excretion and a close relationship between FGF-23 and Klotho is described. The lack of Klotho gene expression is associated with premature phenotypes related to aging as well as to hyperphosphatemia and low levels of vitamin D. Klotho protein forms binary complexes with fibroblast growth factor receptors, increasing Klotho affinity and selectivity for FGF-23, playing an important role in vitamin D synthesis.