Evaluation of in vitro digestion methods and starch structure components as determinants for predicting the glycemic index of rice

Mainstreaming the low glycemic index (GI) trait in breeding programs is constrained by low-throughput and high-cost clinical GI phenotyping. This study aimed to evaluate the potential of starch fine structure components and simulated digestion parameters in predicting GI in rice. Amylose (AM1 and AM2; r = −0.94 and r = −0.80, respectively, p < .05) and amylopectin fine structure (MCAP, SCAP, and SCAP1; r = 0.78-0.86, p < .05) measured through size-exclusion chromatography along with resistant starch (r = −0.81, p < .05) in seven (7) rice accessions showed high correlation with in vivo GI. Meanwhile, starch hydrolysis extent (SH) and the corresponding area under the digestion curve (AUC) obtained through in vitro digestion were found to be of higher correlation with GI, even within shorter digestion periods of 5 min or 30 min (r = 0.96, p < .01). These results highlight the potential use of these parameters as predictors of GI, with improved predictive capacity through a multiple regression model. Higher correlations of simulated digestion AUC with GI may be due to its ability to account for the overall food matrix native macro- and micro-structures, gaining an added advantage over SEC method as a predictive tool in studying rice GI variability. Validation in a larger population is an inevitable next step

The role of cystinosin in the intermediary thjiol metabolism and redox homeostasis in kidney proximal tubular cells

Cystinosin is a lysosomal transmembrane protein which facilitates transport of the disulphide amino acid cystine (CySS) from the lysosomes of the cell. This protein is encoded by the CTNS gene which is defective in the lysosomal storage disorder, cystinosis. Because of the apparent involvement of cystinosin in the intermediary thiol metabolism, its discovery has fuelled investigations into its role in modulating cellular redox homeostasis. The kidney proximal tubular cells (PTCs) have become the focus of various studies on cystinosin since the protein is highly expressed in these cells and kidney proximal tubular transport dysfunction is the foremost clinical manifestation of cystinosis. The lysosomal CySS pool is a major source of cytosolic cysteine (Cys), the limiting amino acid for the synthesis of an important antioxidant glutathione (GSH) via the γ-glutamyl cycle. Therefore, loss of cystinosin function is presumed to lead to cytosolic deficit of Cys which may impair GSH synthesis. However, studies using in vitro models lacking cystinosin yielded inconsistent results and failed to establish the mechanistic role of cystinosin in modulating GSH synthesis and redox homeostasis. Because of the complexity of the metabolic micro- and macro-environment in vivo, using in vitro models alone may not be able to capture the complete sequence of biochemical and physiological events that occur as a consequence of loss of cystinosin function. The coexistence of pathways for the overall handling and disposition of GSH, the modulation of CTNS gene by intracellular redox status and the existence of a non-canonical isoform of cystinosin may constitute possible rescue mechanisms in vivo to remediate redox perturbations in renal PTCs. Importantly, the mitochondria seem to play a critical role in orchestrating redox imbalances initiated by cystinosin dysfunction. Non-invasive techniques such as in vivo magnetic resonance imaging with the aid of systems biology approaches may provide invaluable mechanistic insights into the role of cystinosin in the essential intermediary thiol metabolism and in the overall regulation cellular redox homeostasis

Facile Green Synthesis of Silver Nanoparticles Using Rubus rosifolius Linn Aqueous Fruit Extracts and its Characterization

Rubus rosifolius Linn is a wild raspberry found in the Philippines. The fruit extract is found to be rich in flavonoids, terpenoids, tannins, and polyphenols. It has been shown to contain interesting profiles of antioxidants and it is not previously explored as a reducing agent, specifically in the field of bio-nano research. Some of these antioxidants have been documented to have anti-cancer potential. In this study, the fruit extracts of sampinit were used as a reducing agent for the synthesis of silver nanoparticles (AgNPs) via a ‘one-pot’ facile approach. Sampinit aqueous fruit extract-AgNPs (SAFE-AgNPs) were synthesized by reducing silver ions using sampinit extract. Optical, chemical, and morphological properties of the synthesized SAFE-AgNPs were characterized. Maximal absorption of SAFE-AgNPs was observed at 415 nm which is associated with the characteristic surface plasmon resonance profile of AgNPs. SAFE-AgNPs displayed highly stable and homogeneous nanoparticles with hydrodynamic size of 85.6 ± 0.98 nm and a zeta potential of –29.5 ± 0.96 mV. HR-TEM analysis of a single crystalline image of SAFE-AgNPs corresponds to hexagonal diffraction pattern and the AgNPs were coated with soft carbon-rich materials. EDX and XRF analysis showed that SAFE-AgNPs are chiefly composed of silver (Ag) and carbon (C), where C was largely localized on the surface of AgNPs. FTIR analysis showed that SAFE-AgNPs contains key chemical functional groups associated with sampinit-derived phytoconstituents. Overall, the biosynthesized SAFE-AgNPs produced small size, spherical shape, and monodisperse population which can be a candidate therapeutic agent for the treatment of various diseases such as cancer

Inducible nitric oxide synthase inhibitor 1400W increases Na + ,K + - ATPase levels and activity and ameliorates mitochondrial dysfunction in Ctns null kidney proximal tubular epithelial cells

Nitric oxide (NO) has been shown to play an important role in renal physiology and pathophysiology partly through its influence on various transport systems in the kidney proximal tubule. The role of NO in kidney dysfunction associated with lysosomal storage disorder, cystinosis, is largely unknown. In the present study, the effects of inducible nitric oxide synthase (iNOS)-specific inhibitor, 1400W, on Na+ ,K+ -ATPase activity and expression, mitochondrial integrity and function, nutrient metabolism, and apoptosis were investigated in Ctns null proximal tubular epithelial cells (PTECs). Ctns null PTECs exhibited an increase in iNOS expression, augmented NO and nitrite/nitrate production, and reduced Na+ ,K+ -ATPase expression and activity. In addition, these cells displayed depolarized mitochondria, reduced adenosine triphosphate content, altered nutrient metabolism, and elevated apoptosis. Treatment of Ctns null PTECs with 1400W abolished these effects which culminated in the mitigation of apoptosis in these cells. These findings indicate that uncontrolled NO production may constitute the upstream event that leads to the molecular and biochemical alterations observed in Ctns null PTECs and may explain, at least in part, the generalized proximal tubular dysfunction associated with cystinosis. Further studies are needed to realize the potential benefits of anti-nitrosative therapies in improving renal function and/or attenuating renal injury in cystinosis