The mediating role of cognitive flexibility in the relationship between cognitive emotion regulation strategies and mindfulness in patients with type 2 diabetes.

INTRODUCTION: This study aimed to examine the mediating role of cognitive flexibility in the relationship between cognitive emotion regulation strategies and mindfulness in patients with type 2 diabetes. METHODS: The research was conducted by correlation method) using Structural Equation Modeling). The statistical population consisted of all women and men with type 2 diabetes. Two hundred fifty-three samples were selected by convenience sampling method. The participants responded to the Cognitive Emotion Regulation Questionnaire, the Kentucky inventory of mindfulness skills, and the Cognitive Flexibility Inventory. RESULTS: The results showed that the total path coefficient between the adaptive cognitive emotion regulation strategies and mindfulness (ß = 0.243, P = 0.005) was positive and significant, and the total path coefficient between the maladaptive cognitive emotion regulation strategies and mindfulness (ß = -0.453, P = 0.001) was negative and significant. The path coefficient between cognitive flexibility and mindfulness (ß = 0.273, P = 0.009) was positive and significant. The indirect path coefficient between the adaptive cognitive emotion regulation strategies and mindfulness (ß = 0.094, P = 0.007) was positive and significant, and the indirect path coefficient between the maladaptive cognitive emotion regulation strategies and mindfulness (ß = -0.117, P = 0.009) was negative and significant. CONCLUSION: Improving emotion regulation skills increases cognitive flexibility and mindfulness in patients with type 2 diabetes.

Towards valorization of pectin-rich agro-industrial residues: Engineering of Saccharomyces cerevisiae for co-fermentation of d-galacturonic acid and glycerol.

Pectin-rich plant biomass residues represent underutilized feedstocks for industrial biotechnology. The conversion of the oxidized monomer d-galacturonic acid (d-GalUA) to highly reduced fermentation products such as alcohols is impossible due to the lack of electrons. The reduced compound glycerol has therefore been considered an optimal co-substrate, and a cell factory able to efficiently co-ferment these two carbon sources is in demand. Here, we inserted the fungal d-GalUA pathway in a strain of the yeast S. cerevisiae previously equipped with an NAD-dependent glycerol catabolic pathway. The constructed strain was able to consume d-GalUA with the highest reported maximum specific rate of 0.23 g gCDW-1 h-1 in synthetic minimal medium when glycerol was added. By means of a 13C isotope-labelling analysis, carbon from both substrates was shown to end up in pyruvate. The study delivers the proof of concept for a co-fermentation of the two 'respiratory' carbon sources to ethanol and demonstrates a fast and complete consumption of d-GalUA in crude sugar beet pulp hydrolysate under aerobic conditions. The future challenge will be to achieve co-fermentation under industrial, quasi-anaerobic conditions.

The introduction of the fungal D-galacturonate pathway enables the consumption of D-galacturonic acid by Saccharomyces cerevisiae.

BACKGROUND: Pectin-rich wastes, such as citrus pulp and sugar beet pulp, are produced in considerable amounts by the juice and sugar industry and could be used as raw materials for biorefineries. One possible process in such biorefineries is the hydrolysis of these wastes and the subsequent production of ethanol. However, the ethanol-producing organism of choice, Saccharomyces cerevisiae, is not able to catabolize D-galacturonic acid, which represents a considerable amount of the sugars in the hydrolysate, namely, 18 % (w/w) from citrus pulp and 16 % (w/w) sugar beet pulp. RESULTS: In the current work, we describe the construction of a strain of S. cerevisiae in which the five genes of the fungal reductive pathway for D-galacturonic acid catabolism were integrated into the yeast chromosomes: gaaA, gaaC and gaaD from Aspergillus niger and lgd1 from Trichoderma reesei, and the recently described D-galacturonic acid transporter protein, gat1, from Neurospora crassa. This strain metabolized D-galacturonic acid in a medium containing D-fructose as co-substrate. CONCLUSION: This work is the first demonstration of the expression of a functional heterologous pathway for D-galacturonic acid catabolism in Saccharomyces cerevisiae. It is a preliminary step for engineering a yeast strain for the fermentation of pectin-rich substrates to ethanol.

Pectinase activity determination: an early deceleration in the release of reducing sugars throws a spanner in the works!

Recently, it has been suggested that pectinases could be used to hydrolyze pectin in biorefineries based on pectin-rich agro-industrial wastes. However, for this to be viable, the cost of their production would need to be lowered significantly. In fact, over the last few decades, there have been many attempts to improve pectinase production by existing strains or to screen for new strains from environmental isolates. In these studies, it is necessary to measure pectinase activities. Many researchers use single-time-point assays that involve incubation of pectinolytic extracts with pectic substrates for a fixed time, followed by determination of the liberated reducing sugars. However, different researchers use quite different conditions for this assay. Furthermore, no attention has been given to the reaction profile during the assay. In the current work, we show, for the first time, that a significant deceleration of the rate of liberation of reducing sugars occurs over the first ten minutes of the reaction. As a consequence, the incubation time used in a single-time-point assay has a large effect on the value obtained for the activity. In fact, we demonstrate that, depending on the particular combination of incubation time, pectin concentration and reaction temperature, the same extract could be reported to have activities that differ by an order of magnitude. In addition, we show that the relative activities obtained with polygalacturonic acid do not correlate with those obtained with pectin. We conclude that it is currently impossible to make meaningful comparisons between pectinase activities reported in the literature by workers who have used different assay conditions. Therefore there is an urgent need for the development of a standardized assay for evaluating the saccharification potential of pectinase complexes.

D-galacturonic acid catabolism in microorganisms and its biotechnological relevance.

D-Galacturonic acid is the main constituent of pectin, a naturally abundant compound. Pectin-rich residues accumulate when sugar is extracted from sugar beet or juices are produced from citrus fruits. It is a cheap raw material but currently mainly used as animal feed. Pectin has the potential to be an important raw material for biotechnological conversions to fuels or chemicals. In this paper, we review the microbial pathways for the catabolism of D-galacturonic acid that would be relevant for the microbial conversion to useful products.