Fresh living Arthrospira as dietary supplements: Current status and challenges

© 2019 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (April 2019) in accordance with the publisher’s archiving policyBackground Arthrospira (Spirulina) spp. has long been consumed as a dietary supplement that provides rich natural nutrients consisting of 60–70% proteins including essential amino acids, vitamins, and some minerals. The currently available Spirulina products in the market are mainly hot and spray-dried and their nutritional values are significantly compromised due to degradation of the heat-sensitive bioactive components. Scope and approach This commentary provides a critical view on the differences in main nutritional composition between dried and fresh living Arthrospira. In addition, the current R&D advances in the development of fresh living Arthrospira as a dietary supplement including the cultivation system, preservation and storage, product development, nutritional and functional properties and food safety were critically discussed. Key findings and conclusions Fresh living Arthrospira can better maintain their nutritional, functional, and health values, and therefore could be developed for a new range of Arthrospira derived products. However, the cultivation system that could ensure the food safety and long-term storage technologies to preserve the cell viability in different product formulations are still under development for expanding the commercial applications

Dynamics of a harvested cyanobacteria-fish model with modified Holling type Ⅳ functional response

In this paper, considering the aggregation effect and Allee effect of cyanobacteria populations and the harvesting of both cyanobacteria and fish by human beings, a new cyanobacteria-fish model with two harvesting terms and a modified Holling type Ⅳ functional response function is proposed. The main purpose of this paper is to further elucidate the influence of harvesting terms on the dynamic behavior of a cyanobacteria-fish model. Critical conditions for the existence and stability of several interior equilibria are given. The economic equilibria and the maximum sustainable total yield problem are also studied. The model exhibits several bifurcations, such as transcritical bifurcation, saddle-node bifurcation, Hopf bifurcation and Bogdanov-Takens bifurcation. It is concluded from a biological perspective that the survival mode of cyanobacteria and fish can be determined by the harvesting terms. Finally, concrete examples of our model are given through numerical simulations to verify and enrich the theoretical results

Advances, Synergy, and Perspectives of Machine Learning and Biobased Polymers for Energy, Fuels, and Biochemicals for a Sustainable Future

This review illuminates the pivotal synergy between machine learning (ML) and biopolymers, spotlighting their combined potential to reshape sustainable energy, fuels, and biochemicals. Biobased polymers, derived from renewable sources, have garnered attention for their roles in sustainable energy and fuel sectors. These polymers, when integrated with ML techniques, exhibit enhanced functionalities, optimizing renewable energy systems, storage, and conversion. Detailed case studies reveal the potential of biobased polymers in energy applications and the fuel industry, further showcasing how ML bolsters fuel efficiency and innovation. The intersection of biobased polymers and ML also marks advancements in biochemical production, emphasizing innovations in drug delivery and medical device development. This review underscores the imperative of harnessing the convergence of ML and biobased polymers for future global sustainability endeavors in energy, fuels, and biochemicals. The collective evidence presented asserts the immense promise this union holds for steering a sustainable and innovative trajectory

Bifurcation analysis of Leslie-Gower predator-prey system with harvesting and fear effect

In the paper, a Leslie-Gower predator-prey system with harvesting and fear effect is considered. The existence and stability of all possible equilibrium points are analyzed. The bifurcation dynamic behavior at key equilibrium points is investigated to explore the intrinsic driving mechanisms of population interaction modes. It is shown that the system undergoes various bifurcations, including transcritical, saddle-node, Hopf and Bogdanov-Takens bifurcations. The numerical simulation results show that harvesting and fear effect can seriously affect the dynamic evolution trend and coexistence mode. Furthermore, it is particularly worth pointing out that harvesting not only drives changes in population coexistence mode, but also has a certain degree delay. Finally, it is anticipated that these research results will be beneficial for the vigorous development of predator-prey system

Horizontal migration of Acartia pacifica Steuer (copepoda) in response to UV-radiation

It is known that zooplankton migrate vertically to avoid UV-radiation (UVR 280-400 nm) but little is known if such avoidance happens horizontally Here we showed that the copepod Acartia pacifica avoided UV irradiated fields horizontally Exposure of A pacifica to PAR or PAR + UV-A for 30 min did not make any difference in the horizontal distribution of the individuals However addition of UV-B radiation that is PAR + UV-A + B resulted in uneven distributions among the treatments with significant less individuals compared to the PAR or PAR + UV-A treatments More carotenoids and UV-absorbing compounds were found in the A pacifica individuals that chose to stay under the radiation treatments with UV It is concluded that A. pacifica can migrate horizontally to avoid UV-related harms and those contains more protective compounds were less sensitive to UVR (C) 2010 Elsevier B V All rights reservedNational Basic Research Programs of China [2009CB421207]; National Non-profit Institutes [2008M15]; State Key Laboratory of Marine Environmental Science Xiamen University [MEL-RS0919

Carbon limitation enhances CO2 concentrating mechanism but reduces trichome size in Arthrospira platensis (cyanobacterium)

National Natural Science Foundation [31170338]; Special Prophase Foundation of National Basic Research Programs of China [2012CB426510]; Program for Changjiang Scholars and Innovative Research Team [IRT0941]; MOST [S2012GR0290]; Zhejiang Provincial Natural Science Foundation [LZ12C03001]Arthrospira species grow well under highly enriched inorganic carbon concentrations, but little is known on the effects of inorganic carbon (Ci) limitation on its physiological performance. When Arthrospira platensis D-0083 was grown in a modified medium without NaHCO3 under ambient air of 380 ppm CO2, its trichomes became disassembled while the growth and photosynthetic rates were severely reduced. Phycocyanin and allophycocyanin contents decreased but the carotenoid content increased under the Ci limitation. Compared with the cells grown in Zarrouk medium, the trichomes grown under the Ci limitation increased their photosynthetic apparent affinity for Ci by about 14 times but photochemical quenching capacity was reduced. It appeared that A. platensis increased its CO2 concentrating mechanism by inducing HCO3 (-) transporters and reducing the trichome size which increased filamentous surface to volume ratio

Spiral breakage and photoinhibition of Arthrospira platensis (Cyanophyta) caused by accumulation of reactive oxygen species under solar radiation

Previous studies showed that exposure of Arthrospira spp. spirals to natural levels of solar radiation in the presence of UV radiation (UVR, 280-400 nm) led to the breakage of its spiral structure. However, the underlying mechanisms have not yet been explored. Here, we showed that associated accumulation of reactive oxygen species (ROS) resulted in the spiral breakage by oxidizing the lipids of sheath or cell membrane in Arthospira platensis, and presence of UVR brought about higher accumulation level of the ROS. Activities of superoxide dismutase (SOD) and catalase (CAT) were inhibited by high levels of solar PAR, addition of UVR led to further inhibition of CAT activity. High levels of ROS also decreased the content of photosynthetic pigments, damaged photosystem 11 (PSII) and inhibited the photosynthesis and growth. It is concluded that both UV and high PAR levels could generate higher amounts of ROS, which decreased the photosynthetic performances and led to spiral breakage of A. platensis. (C) 2009 Elsevier B.V. All rights reserved.National Natural Science Foundation of China [40676063, 40876058]; National Non-profit Institutes [2008M15, 2008M10]; State Key Laboratory of Marine Environmental Science, Xiamen University [MELRS0919]; Hainan DIC Microalgae Co

Impacts of UV radiation on respiration, ammonia excretion, and survival of copepods with different feeding habits

Shanghai Municipal Natural Science Foundation [11ZR1449900]; National Natural Science Foundation [40930846, 4112016 4007]; Program for Changjiang Scholars and Innovative Research Team [IRT0941]; China-Japan collaboration project from MOST [S2012GR0290]; State Key Laboratory of Marine Environmental Science, Xiamen University [MELRS0919]Solar ultraviolet radiation (UVR) is known to harm aquatic organisms by damaging key molecules. Here, we showed that UV-A as well as UV-B affected differentially the respiration, ammonia excretion, and mortality of the copepods Pseudodiaptomus marinus (herbivorous) and Labidocera bipinnata (omnivorous). Adding UV-A (320-400 nm, 62.4 W m(-2)) to PAR (400-700 nm, 278 W m(-2)) decreased respiration by 10.2% in P. marinus and 46.1% in L. bipinnata, and additionally, the presence of UV-B (280-320 nm, 2.63 W m(-2)) further decreased it by 8.1 and 18.8%, respectively. The ammonia excretion of P. marinus was suppressed by 13.9% in 30 min exposures to PAR + UV-A compared with those receiving PAR only; however, in the presence of UV-B, it decreased by 13.8% compared to the control. In L. bipinnata, exposure to PAR decreased the ammonia excretion by 33.4%, while the presence of UV-B caused additional suppression by 15.8%. The mortalities of both copepod species increased with prolonged duration under all radiation treatments. More carotenoids and UV-absorbing compounds were found in P. marinus than in L. bipinnata, which could have been responsible for the higher resistance of the former to solar UVR

Behavioral responses of zooplankton to solar radiation changes: in situ evidence

Shanghai Municipal Natural Science Foundation [11ZR1449900]; National Natural Science Foundation [40930846, 41120164007]; Program for Changjiang Scholars and Innovative Research Team [IRT0941]; MOST [S2012GR0290]It is known that copepods can sense solar UV and avoid it vertically or horizontally, but no in situ studies have been documented to monitor their responses to diurnal solar radiation changes. Here, we provided in situ evidence that zooplankton sense changes in solar radiation during a diurnal solar cycle. By comparing the abundance of the zooplankton in a shaded water column with that in the non-shaded adjacent area, we found that, on a cloudy day with low solar radiation levels, the ratios of zooplankton biomass in the shaded areas to those in nearby non-shaded water ranged from 0.90 to 1.49. However, on sunny days with high solar radiation levels, the ratios ranged from 0.83 to 2.88, with the amount of zooplankton in the shaded water being higher than that in the non-shaded area and higher during the periods of higher irradiance levels. These results indicated that the horizontal migration of zooplankton may be a protective strategy against stressful solar radiation