scholarly journals On the Health Benefits vs. Risks of Seaweeds and Their Constituents: The Curious Case of the Polymer Paradigm

Marine Drugs ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 164
Author(s):  
João Cotas ◽  
Diana Pacheco ◽  
Glacio Souza Araujo ◽  
Ana Valado ◽  
Alan T. Critchley ◽  
...  

To exploit the nutraceutical and biomedical potential of selected seaweed-derived polymers in an economically viable way, it is necessary to analyze and understand their quality and yield fluctuations throughout the seasons. In this study, the seasonal polysaccharide yield and respective quality were evaluated in three selected seaweeds, namely the agarophyte Gracilaria gracilis, the carrageenophyte Calliblepharis jubata (both red seaweeds) and the alginophyte Sargassum muticum (brown seaweed). It was found that the agar synthesis of G. gracilis did not significantly differ with the seasons (27.04% seaweed dry weight (DW)). In contrast, the carrageenan content in C. jubata varied seasonally, being synthesized in higher concentrations during the summer (18.73% DW). Meanwhile, the alginate synthesis of S. muticum exhibited a higher concentration (36.88% DW) during the winter. Therefore, there is a need to assess the threshold at which seaweed-derived polymers may have positive effects or negative impacts on human nutrition. Furthermore, this study highlights the three polymers, along with their known thresholds, at which they can have positive and/or negative health impacts. Such knowledge is key to recognizing the paradigm governing their successful deployment and related beneficial applications in humans.

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1105
Author(s):  
Fernanda Erpel ◽  
María Salomé Mariotti-Celis ◽  
Javier Parada ◽  
Franco Pedreschi ◽  
José Ricardo Pérez-Correa

Brown seaweed phlorotannins have shown the potential to promote several health benefits. Durvillaea incurvata and Lessonia spicata—species that are widely distributed in central and southern Chile—were investigated to obtain phlorotannin extracts with antioxidant and antihyperglycemic potential. The use of an environmentally friendly and food-grade glycerol-based pressurized hot liquid extraction (PHLE) process (15% v/v glycerol water) was assessed for the first time to obtain phlorotannins. Multiple effects were analyzed, including the effect of the species, harvesting area (Las Cruces and Niebla), and anatomical part (holdfast, stipe, and frond) on the extracts’ polyphenol content (TPC), antioxidant capacity (AC), and carbohydrate-hydrolyzing enzyme—α-glucosidase and α-amylase—inhibitory activity. Contaminants, such as mannitol, heavy metals (As, Cd, Pb, Hg, and Sn), and 5-hydroxymethylfurfural (HMF), were also determined. The anatomical part used demonstrated a significant impact on the extracts’ TPC and AC, with holdfasts showing the highest values (TPC: 95 ± 24 mg phloroglucinol equivalents/g dry extract; DPPH: 400 ± 140 μmol Trolox equivalents/g dry extract; ORAC: 560 ± 130 μmol TE/g dry extract). Accordingly, holdfast extracts presented the most potent α-glucosidase inhibition, with D. incurvata from Niebla showing an activity equivalent to fifteen times that of acarbose. Only one frond and stipe extract showed significant α-glucosidase inhibitory capacity. No α-amylase inhibition was found in any extract. Although no HMF was detected, potentially hazardous cadmium levels (over the French limit) and substantial mannitol concentrations—reaching up to 50% of the extract dry weight—were found in most seaweed samples and extracts. Therefore, further purification steps are suggested if food or pharmaceutical applications are intended for the seaweed PHLE extracts obtained in this study.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam Yousif Adam Ali ◽  
Muhi Eldeen Hussien Ibrahim ◽  
Guisheng Zhou ◽  
Nimir Eltyb Ahmed Nimir ◽  
Aboagla Mohammed Ibrahim Elsiddig ◽  
...  

AbstractSalinity one of environmental factor that limits the growth and productivity of crops. This research was done to investigate whether GA3 (0, 144.3, 288.7 and 577.5 μM) and nitrogen fertilizer (0, 90 and 135 kg N ha−1) could mitigate the negative impacts of NaCl (0, 100, and 200 mM NaCl) on emergence percentage, seedling growth and some biochemical parameters. The results showed that high salinity level decreased emergence percentage, seedling growth, relative water content, chlorophyll content (SPAD reading), catalase (CAT) and peroxide (POD), but increased soluble protein content, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. The SOD activity was decreased by nitrogen. However, the other measurements were increased by nitrogen. The interactive impact between nitrogen and salinity was significant in most parameters except EP, CAT and POD. The seedling length, dry weight, fresh weight, emergence percentage, POD, soluble protein and chlorophyll content were significantly affected by the interaction between GA3 and salinity. The GA3 and nitrogen application was successful mitigating the adverse effects of salinity. The level of 144.3 and 288.7 μm GA3 and the rate of 90 and 135 kg N ha−1 were most effective on many of the attributes studied. Our study suggested that GA3 and nitrogen could efficiently protect early seedlings growth from salinity damage.


Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 260 ◽  
Author(s):  
Alessandro Calamai ◽  
Enrico Palchetti ◽  
Alberto Masoni ◽  
Lorenzo Marini ◽  
David Chiaramonti ◽  
...  

In recent years, biochar has generated global interest in the areas of sustainable agriculture and climate adaptation. The main positive effects of biochar were observed to be the most remarkable when nutrient-rich feedstock was used as the initial pyrolysis material (i.e., anaerobic digestate). In this study, the influence of solid anaerobic digestate and biochar that was produced by the slow pyrolysis of solid digestate was evaluated by comparing the differences in the crop growth performances of Pelargonium graveolens. The experiment was conducted in a greenhouse while using three different growth media (i.e., solid digestate, biochar, and vermiculite). The results indicated that: (i) the pyrolysis of solid digestate caused a reduction in the bulk density (−52%) and an increase in the pH (+16%) and electrical conductivity (+9.5%) in the derived biochar; (ii) the best crop performances (number of leaves, number of total branches, and plant dry weight) were found using biochar, particularly for plant dry weight (+11.4%) and essential oil content (+9.4%); (iii) the essential oil quality was slightly affected by the growth media; however, the main chemical components were found within the acceptable range that was set by international standard trade; and, iv) biochar induced the presence of leaf chlorosis in Pelargonium graveolens.


PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0206734 ◽  
Author(s):  
Alexandra Serebryakova ◽  
Tania Aires ◽  
Frédérique Viard ◽  
Ester A. Serrão ◽  
Aschwin H. Engelen

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245505
Author(s):  
Xiaofei Chen ◽  
Ruidong Zhang ◽  
Yifan Xing ◽  
Bing Jiang ◽  
Bang Li ◽  
...  

Sorghum [Sorghum bicolor (L.) Moench] seed germination is sensitive to salinity, and seed priming is an effective method for alleviating the negative effects of salt stress on seed germination. However, few studies have compared the effects of different priming agents on sorghum germination under salt stress. In this study, we quantified the effects of priming with distilled water (HP), sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl2), and polyethylene glycol (PEG) on sorghum seed germination under 150 mM NaCl stress. The germination potential, germination rate, germination index, vigor index, root length, shoot length, root fresh weight, shoot fresh weight, root dry weight, and shoot dry weight were significantly reduced by salt stress. Different priming treatments alleviated the germination inhibition caused by salt stress to varying degrees, and 50 mM CaCl2 was the most effective treatment. In addition, the mitigation effect of priming was stronger on root traits than on shoot traits. Mitigation efficacy was closely related to both the type of agent and the concentration of the solution. Principal component analysis showed that all concentrations of CaCl2 had higher scores and were clearly distinguished from other treatments based on their positive effects on all germination traits. The effects of the other agents varied with concentration. The priming treatments were divided into three categories based on their priming efficacy, and the 50, 100, and 150 mM CaCl2 treatments were placed in the first category. The 150 mM KCl, 10% PEG, HP, 150 mM NaCl, 30% PEG, and 50 mM KCl treatments were placed in the second category, and the 100 mM NaCl, 100 mM KCl, 20% PEG, and 50 mM NaCl treatments were least effective and were placed in the third category. Choosing appropriate priming agents and methods for future research and applications can ensure that crop seeds germinate healthily under saline conditions.


Author(s):  
Supattra Maneein ◽  
John J. Milledge ◽  
Birthe V. Nielsen

AbstractSargassum muticum is a brown seaweed which is invasive to Europe and currently treated as waste. The use of S. muticum for biofuel production by anaerobic digestion (AD) is limited by low methane (CH4) yields. This study compares the biochemical methane potential (BMP) of S. muticum treated in three different approaches: aqueous methanol (70% MeOH) treated, washed, and untreated. Aqueous MeOH treatment of spring-harvested S. muticum was found to increase CH4 production potential by almost 50% relative to the untreated biomass. The MeOH treatment possibly extracts AD inhibitors which could be high-value compounds for use in the pharmaceutical industry, showing potential for the development of a biorefinery approach; ultimately exploiting this invasive seaweed species.


2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Judit Bednárik

Manapság egyre többet emlegetjük a közoktatásban, hogy milyen nagymértékben befolyásolja egy iskola sikerességét a vezető személye, a vezetés rátermettsége, kompetenciája, amely természetesen igaz is, azonban azt tapasztalom, hogy ezzel párhuzamosan egyre gyakrabban feledkezünk meg arról, hogy az iskola legfontosabb és legértékesebb szegmense valójában a diákság. Szakgimnáziumi illetve szakközépiskolai tanárként, valamint osztályfőnökként mindig az ő érdekeiket tartottam szem előtt; az ő viselkedésüknek megfigyelését és megértését, lelki és intellektuális fejlődésük nyomon követését kiemelt feladatomnak érzem. Vizsgálatomban egy ún. panelvizsgálatnak a segítségével 30 szakgimnáziumi és 30 szakközépiskolai tanulót kérdeztem meg a következő témákról: a vizsgált tanuló önértékelése, a vizsgált tanuló tapasztalata saját szüleinek nevelői attitűdjéről, valamint a vizsgált tanuló élménye az általa leggyakrabban tapasztalt pedagógusi attitűdökről. Ezután a felmérés kiértékelését követően igyekeztem összefüggést keresni a szülői valamint pedagógusi attitűdök és a tanuló önértékelése között, azt remélve, hogy mérhető bizonyítékot kapok arra vonatkozóan, mely szülői illetve mely pedagógusi attitűdök befolyásolják kedvezően, és melyek befolyásolják negatívan a tanulók önértékelését. Ha ez valóban mérhető, akkor célzottabb nevelési módszereket alkalmazhatunk a tanulók motiválása, egészséges énképének kialakítása érdekében, valamint információkat gyűjthetünk arról, mely életkorban mely pedagógusi attitűdök hatnak leginkább pozitívan a tanulói önértékelésre, ami segítségül szolgálhat a lehető leghatékonyabb tanári kar megszervezésében, illetve a pedagógusok munkájának orientálásában.These days, it is more and more often mentioned how strongly the person of the leader and the aptness and competence of the leadership influence the successfulness of the school in public education, and meanwhile we more and more often forget that the most important and most valuable segment of the school is in fact students. As a vocational school teacher, as well as a class-teacher, I have always focused on their interests, and have considered as a prime task to monitor and understand their behaviour and to follow their mental and intellectual development. In my examination, with the help of a so-called panel research, I asked 30 vocational secondary school students and 30 vocational technical school students about the following issues: self-evaluation of the examined student, the student’s experience on the educational attitudes of his/her own parents and the student’s experience on the teachers’ attitudes he/she meets the most often. After having the survey evaluated, I tried to find interconnections between the parents’ and the teachers’ attitudes and the student’s self-estimation, hoping that I would get a measurable proof of what attitudes have a positive influence on the students’ self-estimation and what have negative impacts. In case this is really measurable, we can apply more targeted educational methods to motivate the students and to develop a healthy self-image, and we can also gather information on the teachers’ attitudes exerting the most positive effects on the students’ self-estimation at the certain ages, which can help to organize the most effective teaching staff possible and the orientation of the teachers’ work.


2016 ◽  
Vol 31 (4) ◽  
pp. 567-585 ◽  
Author(s):  
Daniel Wheatley

This article considers the impact of flexible working arrangements (FWAs), using the British Household Panel Survey and Understanding Society, 2001–10/11. Results of panel logit, ANCOVA and change-score analysis are indicative of positive impacts from use of a number of FWAs, including homeworking having positive effects for men and women on job and leisure satisfaction. However, findings reveal gaps in availability and use of FWAs, and highlight the gendered nature of flexible employment. Flexi-time, the most common FWA among men, has positive effects as it facilitates management of household responsibilities while maintaining full-time employment. Part-time and homeworking are also positive, consistent with men using FWAs with a greater degree of choice. Women more often are constrained in their use of FWAs, often into working reduced hours. Consequently, FWAs have negative impacts for some women, on job (part-time when used for extended periods, flexi-time), leisure (job-share, flexi-time) and life satisfaction (job-share).


2017 ◽  
Vol 98 (8) ◽  
pp. 1935-1944 ◽  
Author(s):  
Martyn Kurr ◽  
Andrew J. Davies

Invasive algae can have substantial negative impacts in their invaded ranges. One widely cited mechanism that attempts to explain how invasive plants and algae are often able to spread quickly, and even become dominant in their invaded ranges, is the Enemy Release Hypothesis. This study assessed the feeding behaviours of two species of gastropod herbivore from populations exposed to the invasive alga Sargassum muticum for different lengths of time. Feeding trials, consisting of both choice and no-choice, showed that the herbivores from older stands (35–40 years established) of S. muticum were more likely to feed upon it than those taken from younger (10–19 years established) stands. These findings provide evidence in support of the ERH, by showing that herbivores consumed less S. muticum if they were not experienced with it. These findings are in accordance with the results of other feeding-trials with S. muticum, but in contrast to research that utilizes observations of herbivore abundance and diversity to assess top-down pressure. The former tend to validate the ERH, and the latter typically reject it. The potential causes of this disparity are discussed, as are the importance of palatability, herbivore species and time-since-invasion when considering research into the ERH. This study takes an important, yet neglected, approach to the study of invasive ecology.


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