Light quality modulates metabolic synchronization over the diel phases of crassulacean acid metabolism.

Temporal compartmentation of carboxylation processes is a defining feature of crassulacean acid metabolism and involves circadian control of key metabolic and transport steps that regulate the supply and demand for carbon over a 24h cycle. Recent insights on the molecular workings of the circadian clock and its connection with environmental inputs raise new questions on the importance of light quality and, by analogy, certain photoreceptors for synchronizing the metabolic components of CAM. The present work tested the hypothesis that optimal coupling of stomatal conductance, net CO2 uptake, and the reciprocal turnover of carbohydrates and organic acids over the diel CAM cycle requires both blue and red light input signals.

Sedoheptulose accumulation under CO₂ enrichment in leaves of Kalanchoë pinnata: a novel mechanism to enhance C and P homeostasis?

In contrast to the well-documented roles of its mono- and bisphosphate esters, the occurrence of free sedoheptulose in plant tissues remains a matter of conjecture. The present work sought to determine the origin of sedoheptulose formation in planta, as well as its physiological importance. Elevated CO2 and sucrose induction experiments were used to study sedoheptulose metabolism in the Crassulacean acid metabolism (CAM) plants Kalanchoë pinnata and Sedum spectabile.

Bacterial antagonism against periodontopathogens.

Background: The aim of the current study is to compare the prevalence of commensal bacteria, with beneficial properties, for healthy and diseased individuals and additionally to examine the inhibitory effect of some commercial dietary probiotics on periodontopathogens, comparing this inhibitory effect to that of orally derived beneficial bacteria.

Methods: Subgingival plaque samples from 35 patients (healthy and periodontitis patients) were analyzed. Growth inhibition of the periodontal pathogens Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans was examined using the agar overlay technique and agar well diffusion method.

Crassulacean acid metabolism under severe light limitation: a matter of plasticity in the shadows?

Despite the increased energetic costs of CAM compared with C(3) photosynthesis, it is hypothesized that the inherent photosynthetic plasticity of CAM allows successful acclimation to light-limiting conditions. The present work sought to determine if CAM presented any constraints to short and longer term acclimation to light limitation and to establish if and how metabolic and photosynthetic plasticity in the deployment of the four phases of CAM might facilitate acclimation to conditions of deep shade. Measurements of leaf gas exchange, organic acids, starch and soluble sugar (glucose, fructose, and sucrose) contents were made in the leaves of the constitutive CAM bromeliad Aechmea 'Maya' over a three month period under severe light limitation.

Seasonal influences on carbohydrate metabolism in the CAM bromeliad Aechmea 'Maya': consequences for carbohydrate partitioning and growth.

Background And Aims: Photosynthetic plasticity in response to a range of environmental factors that include [CO(2)], water availability, light intensity and temperature, is ubiquitous among plants with crassulacean acid metabolism (CAM). The present study examined how seasonal changes in light availability, as experienced by greenhouse CAM crops in northern latitude regions, influence diel carboxylation patterns and impact on carbon gain and seasonal accumulation of biomass.

Methods: In the CAM bromeliad Aechmea 'Maya' integrated measurements of leaf gas exchange, diel metabolite dynamics (e.

Differential usage of storage carbohydrates in the CAM bromeliad Aechmea 'Maya' during acclimation to drought and recovery from dehydration.

CAM requires a substantial investment of resources into storage carbohydrates to account for nocturnal CO(2) uptake, thereby restricting carbohydrate partitioning to other metabolic activities, including dark respiration, growth and acclimation to abiotic stress. Flexible modulation of carbon flow to the different competing sinks under changing environmental conditions is considered a key determinant for the growth, productivity and ecological success of the CAM pathway. The aim of the present study was to examine how shifts in carbohydrate partitioning could assure maintenance of photosynthetic integrity and a positive carbon balance under conditions of increasing water deprivation in CAM species.