Extraction of sulfated polysaccharides by autohydrolysis of brown seaweed Fucus vesiculosus

The extraction of sulfated polysaccharides (fucoidan) by autohydrolysis (AH) of brown seaweed Fucus vesiculosus was studied. Experimental assays were performed under different conditions of temperature (160 to 200°C) and reaction time (10 to 30 min) according to a 2² central composite design, and the conditions able to maximize the fucoidan yield were selected. The alga degradation and the total sugar yield in the liquor after AH were also determined to each experimental condition. The highest fucoidan yield (～16.5% w/w) was obtained when the AH process was performed at 180°C for 20 min. This product was characterized by high-performance liquid chromatography, infrared analysis spectroscopy, and thermal gravimetric analyses, which verified the presence of fucose and galactose as main components (70:30% mol ratio, in average) and an SO₃ content higher than 20%. AH process under optimum reaction conditions was an effective method to recover fucoidan from F. vesiculosus. The use of this technology brings also important advantages from economical and environmental viewpoints since it does not require the use of chemical solvent and generates less waste when compared to conventional extraction procedures.     

Variation in Activity State,Axonal Projection,and Position Define the Transcriptional Identity of Individual Neocortical Projection Neurons

1. Download high-res image (179KB)
2. Download full-size image

     

Disruptions in sleep–wake cycles in community-dwelling cancer patients receiving palliative care and their correlates

Significant disruptions in sleep–wake cycles have been found in advanced cancer patients in prior research. However, much remains to be known about specific sleep–wake cycle variables that are impaired in patients with a significantly altered performance status. More studies are also needed to explore the extent to which disrupted sleep–wake cycles are related to physical and psychological symptoms, time to death, maladaptive sleep behaviors, quality of life and 24-h light exposure. This study conducted in palliative cancer patients was aimed at characterizing patients’ sleep–wake cycles using various circadian parameters (i.e. amplitude, acrophase, mesor, up-mesor, down-mesor, rhythmicity coefficient). It also aimed to compare rest–activity rhythm variables of participants with a performance status of 2 vs. 3 on the Eastern Cooperative Oncology Group scale (ECOG) and to evaluate the relationships of sleep–wake cycle parameters with several possible correlates. The sample was composed of 55 community-dwelling cancer patients receiving palliative care with an ECOG of 2 or 3. Circadian parameters were assessed using an actigraphic device for seven consecutive 24-h periods. A light recording and a daily pain diary were completed for the same period. A battery of self-report scales was also administered. A dampened circadian rhythm, a low mean activity level, an early mean time of peak activity during the day, a late starting time of activity during the morning and an early time of decline of activity during the evening were observed. In addition, a less rhythmic sleep–wake cycle was associated with a shorter time to death (from the first home visit) and with a lower 24-h light exposure. Sleep–wake cycles are markedly disrupted in palliative cancer patients, especially, near the end of life. Effective non-pharmacological interventions are needed to improve patients’ circadian rhythms, including perhaps bright light therapy.     

Biotechnological production and application of fructooligosaccharides

Currently, prebiotics are all carbohydrates of relatively short chain length. One important group is the fructooligosaccharides (FOS), a special kind of prebiotic associated to the selective stimulation of the activity of certain groups of colonic bacteria. They have a positive and beneficial effect on intestinal microbiota, reducing the incidence of gastrointestinal infections and also possessing a recognized bifidogenic effect. Traditionally, these prebiotic compounds have been obtained through extraction processes from some plants, as well as through enzymatic hydrolysis of sucrose. However, different fermentative methods have also been proposed for the production of FOS, such as solid-state fermentations utilizing various agro-industrial by-products. By optimizing the culture parameters, FOS yields and productivity can be improved. The use of immobilized enzymes and cells has also been proposed as being an effective and economic method for large-scale production of FOS. This article is an overview of the results considering recent studies on FOS biosynthesis, physicochemical properties, sources, biotechnological production and applications.