Evidence for an early green/red photocycle that precedes the diversification of GAF domain photoreceptor cyanobacteriochromes.

Phytochromes are linear tetrapyrrole-binding photoreceptors in eukaryotes and bacteria, primarily responding to red and far-red light signals reversibly. Among the GAF domain-based phytochrome superfamily, cyanobacteria-specific cyanobacteriochromes show various optical properties covering the entire visible region. It is unknown what physiological demands drove the evolution of cyanobacteriochromes in cyanobacteria. Here, we utilize ancestral sequence reconstruction and biochemical verification to show that the resurrected ancestral cyanobacteriochrome proteins reversibly respond to green and red light signals. pH titration analyses indicate that the deprotonation of the bound phycocyanobilin chromophore is crucial to perceive green light. The ancestral cyanobacteriochromes show only modest thermal reversion to the green light-absorbing form, suggesting that they evolved to sense the incident green/red light ratio. Many cyanobacteria can utilize green light for photosynthesis using phycobilisome light-harvesting complexes. The green/red sensing cyanobacteriochromes may have allowed better acclimation to changing light environments by rearranging the absorption capacity of the phycobilisome through chromatic acclimation.

Assessment of the Diagnostic Utility of Serum Omentin 1 and IL-6 in Early Stages of Diabetic Nephropathy.

In India, diabetic nephropathy (DN) is the most common cause of chronic kidney disease. Timely detection of microalbuminuria and appropriate intervention can reverse or arrest the progress of nephropathy. The pathogenesis of diabetic nephropathy has revealed that during the early onset of kidney involvement in diabetics, inflammation and fibrosis progress from tubular to glomerular damage. This study was designed to elucidate the association of chemokines, Omentin 1, and interleukin 6 (IL-6) with microalbuminuria. MATERIAL: Settings and Design: This cross-sectional observational study was conducted as a collaborated study in the Departments of General Medicine and Biochemistry, All India Institute of Medical Sciences, Bhubaneswar, India, during 2019-2020. METHODS AND MATERIAL: Our study group comprised 116 diabetes mellitus patients. They were grouped into two, each of 58 on the basis of their urine albumin levels; Group 1 (controls) had UACR < 30 µg/mg, eGFR> 90ml/ min and Group 2 (cases) had UACR ≥ 30 µg/mg and < 300 µg/mg, eGFR>60ml/min and < 90ml/min. Serum omentin 1 and IL-6, creatinine, glycated haemoglobin (HbA1c), fasting (FBS) and postprandial blood sugar (PPBS), lipid profile, total protein, albumin, and fasting insulin, HOMA-IR were studied. OBSERVATION: Our study showed that Omentin 1 levels were decreased, and IL-6 levels were increased in the DN group compared to the T2DM without DN. The risk estimates calculated revealed that diabetes mellitus patients having an IL-6: omentin ratio ≥ 0.26 had Odds of 3.97 of developing DN, which was statistically significant (CI 2.36-6.68). Therefore, a ratio of ≤ 0.26 was found to be kidney protective among diabetes mellitus patients. CONCLUSION: From the results of this present study, we recommend that estimation of serum IL-6: omentin 1 ratio of T2DM will aid in identifying early stages of DN before the onset of microalbuminuria.