Explore the vast range of titles available.

Abiotic stresses, such as drought, high salinity and extreme temperatures, pose one of the most important constraints to plant growth and productivity in many regions of the world. A number of investigations have shown that plants, including several important crops, remobilize their starch reserve to release energy, sugars and derived metabolites to help mitigate the stress. This is an essential process for plant fitness with important implications for plant productivity under challenging environmental conditions. In this Tansley insight, we evaluate the current literature on starch metabolism in response to abiotic stresses, and discuss the key enzymes involved and how they are regulated.

Background It has been suggested that coffee may affect the gut-brain axis with conflicting outcomes. Moreover, there is insufficient evidence to determine whether the type or temperature of coffee consumed will have a different impact on the gut-brain axis. The purpose of this study was to investigate the effects of acute coffee consumption on the following: 1. self-reported GI symptoms and salivary gastrin, 2. stress indices [salivary cortisol and alpha-amylase (sAA)] and psychometric measures, and 3. blood pressure (BP), in healthy, daily coffee consuming individuals in non-stressful conditions. Methods This was a randomized, double blind, crossover clinical trial, in which 40 healthy individuals (20 men, 20 women), 20–55 years of age, randomly consumed four 200 ml coffee beverages containing 160 mg caffeine (hot and cold instant coffee, cold espresso, hot filtered coffee), 1 week apart. Salivary samples and psychometric questionnaires were collected at baseline and post-coffee consumption at 15,30, and 60 min for salivary gastrin and sAA measurements and at 60,120, and 180 min for cortisol measurements. BP was measured at beginning and end of each intervention. ClinicalTrials.gov ID: NCT02253628 Results Coffee consumption significantly increased sAA activity ( P  = 0.041), with significant differences only between cold instant and filter coffee at 15 and 30 min post-consumption ( P  < 0.05). Coffee temporarily increased salivary gastrin, without differences between coffee types. Coffee did not affect salivary cortisol or self-reported anxiety levels. Coffee consumption significantly increased BP, within the healthy physiological levels, in a gender specific manner at the end of the experimental periods, without differences between coffee types. Conclusion Acute coffee consumption in non-stressful conditions activated sAA and BP but not salivary cortisol, indicating activation of the sympathetic nervous system. Post-coffee sAA increase without a concomitant cortisol increase may also indicate that coffee may have some anti-stress properties.

Background Physical activity has shown to be effective in anxiety disorders. For specific phobia, no studies are available that systematically examined the effects of an aerobic exercise intervention on phobic fear within a randomized‐controlled design. Therefore, we investigated the acute effect of a standardized aerobic training on clinical symptoms of dental phobia as well as on stress‐related neurobiological markers. Methods Within a crossover design, 30 patients with dental phobia (mean age: 34.1 years; mean score of the Dental Anxiety Scale: 18.8) underwent two minor dental interventions separated by 7 days. Dental treatment was performed after 30 min of physical activity at either 20% VO2 max (control) or 70% VO2 max (intervention), respectively. To control for habituation, patients were randomly assigned to one of the two conditions prior to the first intervention. Moreover, saliva samples were collected at five times in order to determine changes in salivary cortisol (sC) and alpha‐amylase (sAA) due to treatment. Results In comparison to baseline, aerobic exercise within 70% VO2 max significantly reduced clinical anxiety and sC concentrations before, during, and after the dental treatment. In contrast, the control condition led to decreased sAA levels at different time points of measurement. Habituation occurred at the second study day, independent of the order. Conclusions Our study provides evidence for an effect of moderate–intense exercise on clinical symptoms and sC in patients with dental phobia. Therefore, acute aerobic exercise might be a simple and low‐cost intervention to reduce disorder‐specific phobic fear.

Music listening in daily life is associated with stress-reducing effects on the individual with increasing effects when music listening occurs in a social context. As little is known about effects on couples, we investigated whether beneficial effects can be found in couples. Forty heterosexual couples were investigated using ambulatory assessment. Participants completed six assessments on music listening and subjective stress per day for five consecutive days. With each assessment, saliva samples for the later analysis of cortisol and alpha-amylase were collected. Music listening affected biopsychological stress markers in women and men, however in different ways: While music listening reduced cortisol in women, it increased alpha-amylase in men. Dyadic effects of music listening on stress markers were found. Men showed lower secretion of cortisol if women listened to music which was more pronounced when couples shared musical preferences. Both men and women showed higher alpha-amylase activity when their partner had listened to music. Music listening influences couples’ psychobiological stress levels in a sex-dependent manner with evidence of dyadic co-variation in physiological responses to music. Interventions for promoting stress reduction should consider that women and men differ in their use of music in everyday life.

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. Cardiovascular diseases, kidney damage and neuropathy are the main cause of high mortality rates among individuals with diabetes. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target alpha-amylase and alpha-glucosidase, enzymes that catalyzes starch hydrolysis in the intestine. At present, approved inhibitors for these enzymes are restricted to acarbose, miglitol and voglibose. Although these inhibitors retard glucose absorption, undesirable gastrointestinal side effects impede their application. Therefore, research efforts continue to seek novel inhibitors with improved efficacy and minimal side effects. Natural products of plant origin have been a valuable source of therapeutic agents with lesser toxicity and side effects. The anti-diabetic potential through alpha-glucosidase inhibition of plant-derived molecules are summarized in this review. Eight molecules (Taxumariene F, Akebonoic acid, Morusin, Rhaponticin, Procyanidin A2, Alaternin, Mulberrofuran K and Psoralidin) were selected as promising drug candidates and their pharmacokinetic properties and toxicity were discussed where available.

Diabetes is a chronic fast-growing metabolic disorder that is characterized by high blood glucose levels. Tagetes minuta L. has been used as a traditional remedy for various illnesses for many years, and, furthermore, its oil is used in the perfume and flavor industries. T. minuta contains various metabolites, such as flavonoids, thiophenes, terpenes, sterols, and phenolics, with varied bioactivities. Flavonoids can inhibit carbohydrate-digesting enzymes, such as alpha-amylase, which is a convenient dietary strategy for controlling hyperglycemia. In the current investigation, the isolated flavonoids quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside), quercetagetin-7-O-β-D-glucopyranoside, quercetagetin-6-O-β-D-glucopyranoside, minutaside A, patuletin-7-O-β-D-glucopyranoside, quercetagetin-7-methoxy-6-O-β-D-glucopyranoside, tagenols A and B, quercetagetin-3,7-dimethoxy-6-O-β-D-glucopyranoside, patuletin, quercetin-3,6-dimethyl ether, and quercetin-3-methyl ether from T. minuta were assessed for their alpha-amylase inhibition (AAI) efficacy using an in vitro assay, as well as molecular docking, dynamics simulation, and ADMET analyses. Our findings show that quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside) (1), quercetagetin-7-O-β-D-glucopyranoside (2), quercetagetin-6-O-β-D-glucopyranoside (3), minutaside A (4), patuletin-7-O-β-D-glucopyranoside (5), and quercetagetin-7-methoxy-6-O-β-D-glucopyranoside (6) had a notable AAI capacity (IC50s ranged from 7.8 to 10.1 μM) compared to acarbose (IC50 7.1 μM). Furthermore, these compounds with the highest binding affinity among the tested flavonoids revealed high docking scores for AA (ranging from −12.171 to 13.882 kcal/mol) compared to that of acarbose (−14.668 kcal/mol). In MDS, these compounds were observed to show maximum stability and the greatest binding free energy, suggesting that they may contend with native ligands. In addition, the ADMET analysis showed that these active compounds had a broad span of drug-like, pharmacokinetic, and physicochemical features and did not possess any considerable undesired effects. The current results suggest the potential of these metabolites as AAI candidates. However, further in vivo and mechanistic studies are warranted to specify the efficacy of these metabolites.

In this study, two different materials—alginate and glutaraldehyde-activated chitosan beads—were used for the co-immobilization of α-amylase, protease, and pectinase. Firstly, optimization of multienzyme immobilization with Na alginate beads was carried out. Optimum Na alginate and CaCl 2 concentration were found to be 2.5% and 0.1 M, respectively, and optimal enzyme loading ratio was determined as 2:1:0.02 for pectinase, protease, and α-amylase, respectively. Next, the immobilization of multiple enzymes on glutaraldehyde-activated chitosan beads was optimized (3% chitosan concentration, 0.25% glutaraldehyde with 3 h of activation and 3 h of coupling time). While co-immobilization was successfully performed with both materials, the specific activities of enzymes were found to be higher for the enzymes co-immobilized with glutaraldehyde-activated chitosan beads. In this process, glutaraldehyde was acting as a spacer arm. SEM and FTIR were used for the characterization of activated chitosan beads. Moreover, pectinase and α-amylase enzymes immobilized with chitosan beads were also found to have higher activity than their free forms. Three different enzymes were co-immobilized with these two materials for the first time in this study.

The hospitalization and the unfamiliar experiences of patients in interventional radiology procedures cause a moderate to high levels of anxiety. This study was aimed to evaluate the anxiolytic effect of Cananga odorata essential oil (COE) aromatherapy in unexperienced patients hospitalized for interventional neuroradiology (INR) procedures. Forty-four patients admitted for their first INR procedure were randomly divided into COE and placebo control groups. COE or distilled water was dropped onto 2 pieces of mulberry paper and attached to the participant's gown at the shoulder level overnight. The main outcomes were observed from the morning salivary cortisol levels and salivary alpha-amylase activity after intervention. The Thai version of Spielberger State-Trait Anxiety Inventory (STAI) and the vital signs (blood pressure and heart rate) were also assessed before and after COE intervention as the secondary outcome. The demographic and baseline data of both groups did not show any significant difference. After intervention, COE group had a significantly lower salivary alpha-amylase activity than placebo control group. The post-intervention scores of Trait (STAI-T) and State (STAI-S) anxiety were significantly less than those of baseline in both groups. Interestingly, the COE group had a greater percentage reduction on STAI-T after intervention than placebo control group. No significant difference was observed in other outcomes. In addition, the salivary alpha-amylase activity was weak but showed significant correlation with STAI anxiety scores. This study indicates that COE aromatherapy reduces the saliva alpha amylase activity and STAI-T anxiety in unexperienced patients hospitalized for INR procedures.

With the advent of green chemistry, the use of enzymes in industrial processes serves as an alternative to the conventional chemical catalysts. A high demand for sustainable processes for catalysis has brought a significant attention to hunt for novel enzymes. Among various hydrolases, the α-amylase has a gamut of biotechnological applications owing to its pivotal role in starch-hydrolysis. Industrial demand requires enzymes with thermostability and to ameliorate this crucial property, various methods such as protein engineering, directed evolution and enzyme immobilisation strategies are devised. Besides the traditional culture-dependent approach, metagenome from uncultured bacteria serves as a bountiful resource for novel genes/biocatalysts. Exploring the extreme-niches metagenome, advancements in protein engineering and biotechnology tools encourage the mining of novel α-amylase and its stable variants to tap its robust biotechnological and industrial potential. This review outlines α-amylase and its genetics, its catalytic domain architecture and mechanism of action, and various molecular methods to ameliorate its production. It aims to impart understanding on mechanisms involved in thermostability of α-amylase, cover strategies to screen novel genes from futile habitats and some molecular methods to ameliorate its properties.

BACKGROUND AND AIMS: The premature production of alpha-amylase without visible germination has been observed in developing grain of many cereals. The phenomenon is associated with cool temperatures in the late stages of grain growth but the mechanisms behind it are largely unknown. The aim of this study was to replicate the phenomenon under controlled conditions and investigate the possibility of a mechanistic link with grain size or endosperm cavity size. METHODS: Five wheat (Triticum aestivum) genotypes differing in their susceptibility to premature alpha-amylase were subjected to a range of temperature shocks in controlled environments. A comparison was then made with plants grown under ambient conditions but with grain size altered by using degraining to increase the assimilate supply. At maturity, alpha-amylase, grain area and endosperm cavity area were measured in individual grains. KEY RESULTS: Both cold and heat shocks were successful in inducing premature alpha-amylase in susceptible genotypes, with cold shocks the most effective. Cold shocks also increased grain area. Degraining resulted in increased grain area overall, but the larger grain did not have higher alpha-amylase. Analysis of individual grain found that instances of high alpha-amylase were not associated with differences in grain area or endosperm cavity area. CONCLUSIONS: Pre-maturity alpha-amylase is associated with temperature shocks during grain filling. In some cases this coincides with an increase in grain area, but there is no evidence of a mechanistic link between high alpha-amylase and grain or endosperm cavity area.