Search results for "alpha-Amylases"
showing 10 items of 28 documents
Changes in carbohydrate metabolism in Plasmopara viticola-infected grapevine leaves.
2011
International audience; The oomycete Plasmopara viticola is responsible for downy mildew, a severe grapevine disease. In infected grapevine leaves, we have observed an abnormal starch accumulation at the end of the dark period, suggesting modifications in starch metabolism. Therefore, several complementary approaches, including transcriptomic analyses, measurements of enzyme activities, and sugar quantification, were performed in order to investigate and to understand the effects of P. viticola infection on leaf starch and-to a larger extent-carbohydrate metabolism. Our results indicate that starch accumulation is associated with an increase in ADP-glucose pyrophosphorylase (AGPase) activit…
Amylase–Trypsin Inhibitors in Wheat and Other Cereals as Potential Activators of the Effects of Nonceliac Gluten Sensitivity
2018
Nonceliac gluten sensitivity (NCGS) is a gluten-related gastrointestinal disorder distinct from celiac disease (CD) and gluten allergy that is not easy to diagnose due to the lack of biomarkers. It is characterized by intestinal symptoms and extraintestinal manifestations with the consumption of gluten-containing foods. In contrast to CD, NCGS patients do not present a genetic predisposition or intestinal villi atrophy. Recent studies question the proinflammatory triggering activity of α-gliadin fraction contained in wheat, since it has been demonstrated that the amylase-trypsin inhibitors (ATIs) exert a strong activating effect on the innate immune response. We aimed to analyze the role of…
Acute stress and working memory in older people.
2015
Several studies have shown that acute stress affects working memory (WM) in young adults, but the effect in older people is understudied. As observed in other types of memory, older people may be less sensitive to acute effects of stress on WM. We performed two independent studies with healthy older men and women (from 55 to 77 years old) to investigate the effects of acute stress (Trier Social Stress Test; TSST) and cortisol on WM. In study 1 (n = 63), after the TSST women (but not men) improved their performance on Digit Span Forward (a measure of the memory span component of WM) but not on Digit Span Backward (a measure of both memory span and the executive component of WM). Furthermore,…
Changes in different salivary biomarkers related to physiologic stress in elite handball players: the case of females
2019
AbstractThis study evaluates pre- and post-match concentrations of salivary cortisol, alpha-amylase (AA) and immunoglobulin A (lgA) in a group of 21 elite female handball players in the Spanish national women’s league. The players’ mean age was 23.0 ± 5.4 years. The concentration of the biomarkers was determined using ELISA. Mean playing time was 25.2 min. The players’ cortisol concentration increased significantly (p < 0.05) whereas the IgA concentration fell significantly (p < 0.01) at the end of the match. There were no significant changes in the concentrations of AA between pre and post-match timepoints. The changes observed in the study also depended on the position played; defen…
Chewing bread: impact on alpha-amylase secretion and oral digestion
2017
During chewing, saliva helps in preparing food bolus by agglomerating formed particles and initiates food enzymatic breakdown. However, limited information is actually available on the adaptation of saliva composition during oral processing of complex foods, especially for foods that are sensitive to salivary enzymes. We addressed this question in the context of starch–based products and salivary alpha-amylase. The objectives were two-fold: 1) determining if salivary alpha-amylase secretion can be modulated by bread type and 2) evaluating the contribution of the oral phase in bread enzymatic breakdown.Mouthfuls of three different wheat breads (industrial, artisan and whole breads) were chew…
Salivary alpha-amylase response to acute psychosocial stress: The impact of age
2011
a b s t r a c t The impact of stress on health varies across the different stages of human life. Aging is associated with psychobiological changes that could limit our ability to cope with stressors. Therefore, it is crucial to clarify the physiological mechanisms that underlie the stress response and the changes that occur in them as we age. Our aim was to investigate age differences in the salivary alpha amylase (sAA) response to stress, and its relationship with other typical stress biomarkers such as cortisol and heart rate (HR). Sixty-two participants divided into two age groups (younger group: N = 31, age range: 18-35 years; older group: N = 31, age range: 54-71 years) were exposed to…
Autonomic markers associated with generalized social phobia symptoms: heart rate variability and salivary alpha-amylase.
2016
The study of autonomic nervous system changes associated with generalized social phobia (GSP) disorder has increased in recent years, showing contradictory results. The present study aimed to evaluate how young people with GSP reacted before, during, and after exposure to the Trier Stress Social Test (TSST), focusing on their autonomic changes (heart rate variability (HRV) and salivary alpha-amylase (sAA)) compared to a control group (non-GSP). Some psychological variables were also considered. Sex was specifically studied as a possible modulator of autonomic fluctuations and psychological state. Eighty young people were randomly distributed into two counterbalanced situations: stress condi…
Acute stress impairs recall after interference in older people, but not in young people.
2013
Stress has been associated with negative changes observed during the aging process. However, very little research has been carried out on the role of age in acute stress effects on memory. We aimed to explore the role of age and sex in the relationship between hypothalamus-pituitary-adrenal axis (HPA-axis) and sympathetic nervous system (SNS) reactivity to psychosocial stress and short-term declarative memory performance. To do so, sixty-seven participants divided into two age groups (each group with a similar number of men and women) were exposed to the Trier Social Stress Test (TSST) and a control condition in a crossover design. Memory performance was assessed by the Rey Auditory Verbal …
Alpha-amylase serum levels in professional soccer players are not related with physical fitness.
2017
Backgorund Recent evidence has showed that serum or salivary values of α-amylase predict endurance running performance. In this study we investigate whether serum α-amylase concentration may be associated with training status during a competitive season and after a detraining period in professional soccer players. Methods The study population consisted in 15 male professional soccer players from an Italian major league team (age [mean±SD] 27±5 years, weight 76.9±4.1 kg, height 1.82±0.05 m). Serum α-amylase levels were measured 3 times during the last part of a competitive season (January, March and May) and just before preseason training (July). Results Metabolic and cardiovascular fitness …
Effects of sex and menstrual cycle phase on cardiac response and alpha- amylase levels in psychosocial stress.
2018
The impact of sex and the menstrual cycle phase on the autonomic response to psychosocial stress remains controversial. This study explored autonomic nervous system activity through salivary alpha-amylase, heart rate, and heart rate variability responses to the Trier Social Stress Test (TSST) in healthy young people. The sample was composed of 25 men, 26 women in the luteal phase, and 25 women in the follicular phase, from 18 to 25 years of age. Participants were exposed to the TSST or a control condition. The results indicate that women in their follicular phase showed a blunted alpha-amylase response to stress compared to men and women in the luteal phase. In addition, men showed higher s…