Toxicity Effects of Titanium Dioxide Nanoparticles in Marine Algae

Titanium dioxide nanoparticles (TiO2) are mineral compounds that had been manipulated to its nano-scale dimension, approximately 1 to 100nm. Nano-scaled TiO2 are claimed to have better chemical, physical and biological properties which make them enormously applied in industrial manufacturing. However, this has become a big threat to the environment due to the increase disposal of TiO2 into the environment whereby both human and other living organisms could be adversely affected. The aim of this study was to study the effects of TiO2 nanoparticles on two marine microalgae Dunaleilla tertiolecta and Pavlova gyrans. The change in photosynthetic pigments chlorophyll a and carotenoid content was used to measure the response of algae species towards the presence of TiO2 nanoparticle. The results showed Dunaleilla tertiolecta was more susceptible to TiO2 nanoparticles with lower effective concentration of 50% (EC50) at 31.25 mg/L compared to Pavlova gyrans. In addition, TiO2 was found to aggregate and adsorb on algal membrane and reduced its motility. In conclusion, TiO2 nanoparticles caused an impactful effect to the ecosystem and the post production wastes should be managed appropriately

Response of marine microalgae towards short single-walled carbon nanotubes

Nanoparticles have vast applications in industrial and consumer products such as household detergents, sunscreen, anti-bacterial clothing, electrical and telecommunication devices, sports equipment, medical treatment tools and others. The production of nanomaterials is increasing remarkably with an expected resultant increase in the distribution of nanoparticles in the environment. Many health problems have been correlated to the exposure of nanoparticles. For instance, engineered carbon nanotubes cause inflammation, fibrosis and oxidative stress in both in vitro and in vivo models and titanium dioxide nanoparticles could lead to chronic airflow obstruction. Marine microalgae play a pivotal role in all marine ecosystems as they form the food and energy base for all organisms living in lakes, ponds, streams and sea. They provide 75% of oxygen content in the atmosphere. Therefore, an effect on algal population may have an important impact on the whole ecosystem. The aim of this study is to assess the toxicity of short single-walled carbon nanotubes (SWCNT) and amount of reactive species oxygen (ROS) released in two marine microalgae Dunaliella tertiolecta and Isochrysis sp using pigment quantification method and H2DCFDA dye. We found that SWCNT reduced the algal cell number by 50% at 30 mg/L and 50 mg/L after 96 h of exposure in Isochrysis sp. and Dunaliella tertiolecta respectively. In addition, 6-10 folds of ROS were released by these marine microalgae when exposed to SWCNT (50 mg/L). In conclusion, the presence of nanoparticles in the environment causes ecotoxicity and its impact to biodata should not be neglected

Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

<p>Abstract</p> <p>Background</p> <p><it>Spirulina </it>is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, <it>Spirulina </it>is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of <it>Spirulina </it>were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from <it>Spirulina </it>based on its protective effect against cell death induced by free radicals.</p> <p>Methods</p> <p>The antioxidant activity of the cold water extract from food-grade <it>Spirulina platensis </it>was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3) cells were incubated for 1 h in medium containing aqueous extract of <it>Spirulina </it>or vitamin C (positive control) at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls).</p> <p>Results</p> <p><it>Spirulina </it>extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL). The extract reduced significantly (p < 0.05) apoptotic cell death due to DPPH and ABTS by 4 to 5-fold although the activity was less than vitamin C. Based on the DPPH assay, the radical scavenging activity of the extract was higher than phycocyanin and was at least 50% of vitamin C and vitamin E. Based on the ABTS assay, the antioxidant activity of the extract at 50 μmug/mL was as good as vitamin C and vitamin E.</p> <p>Conclusions</p> <p>The results showed that aqueous extract of <it>Spirulina </it>has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating <it>Spirulina </it>into food products and beverages to enhance their antioxidant capacity is worth exploring.</p

Marine Algae as a Potential Source for Anti-Obesity Agents

Obesity is a major epidemic that poses a worldwide threat to human health, as it is also associated with metabolic syndrome, type 2 diabetes and cardiovascular disease. Therapeutic intervention through weight loss drugs, accompanied by diet and exercise, is one of the options for the treatment and management of obesity. However, the only approved anti-obesity drug currently available in the market is orlistat, a synthetic inhibitor of pancreatic lipase. Other anti-obesity drugs are still being evaluated at different stages of clinical trials, while some have been withdrawn due to their severe adverse effects. Thus, there is a need to look for new anti-obesity agents, especially from biological sources. Marine algae, especially seaweeds are a promising source of anti-obesity agents. Four major bioactive compounds from seaweeds which have the potential as anti-obesity agents are fucoxanthin, alginates, fucoidans and phlorotannins. The anti-obesity effects of such compounds are due to several mechanisms, which include the inhibition of lipid absorption and metabolism (e.g., fucoxanthin and fucoidans), effect on satiety feeling (e.g., alginates), and inhibition of adipocyte differentiation (e.g., fucoxanthin). Further studies, especially testing bioactive compounds in long-term human trials are required before any new anti-obesity drugs based on algal products can be developed

Metabolomic profiles of tropical Chlorella species in response to physiological changes during nitrogen deprivation

Chlorella species are known to be potential algal candidates for biodiesel production due to their ability to store lipids and their natural metabolic versatility. This study assessed the photosynthetic performance, biochemical composition, and metabolomic profiles of tropical Chlorella UMACC050 harvested from different growth phases in batch culture, grown under nitrogen-replete, and nitrogen-depleted conditions. Physiological data suggested that growth and photosynthetic efficiency were affected during nitrogen deprivation. Nitrogen deprivation resulted in a decrease in biomass productivity and an increase of lipid content. Nitrogen-depletion resulted in an increase in saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA), especially C16:0, C18:0, and C18:1, at the expense of polyunsaturated fatty acids (PUFA). Changes in the metabolomic profiles suggested that there was nitrogen assimilation from proteins and photosynthetic machinery, together with repartitioning of carbon into carbohydrates and lipids in response to nitrogen depletion. Overall, our results expand the current understanding of metabolomics of Chlorella species and provide valuable insights into their lipid accumulation during nitrogen deprivation, which is important for optimization of lipid productivity in the tropical environment

Evaluating anticancer and immunomodulatory effects of spirulina (Arthrospira) platensis and gamma-tocotrienol supplementation in a syngeneic mouse model of breast cancer

Nutrition can modulate host immune responses as well as promote anticancer effects. In this study, two nutritional supplements, namely gamma-tocotrienol (γT3) and Spirulina, were evaluated for their immune-enhancing and anticancer effects in a syngeneic mouse model of breast cancer (BC). Five-week-old female BALB/c mice were fed Spirulina, γT3, or a combination of Spirulina and γT3 (Spirulina + γT3) for 56 days. The mice were inoculated with 4T1 cells into their mammary fat pad on day 28 to induce BC. The animals were culled on day 56 for various analyses. A significant reduction (p 0.05) differences in the expression of MIG-6, Cadherin 13, BIRC5, and Serpine1 upon combined feeding. This showed that combined γT3 + Spirulina treatment did not show any synergistic anticancer effects in this study model

Heavy metal pollution in Antarctica and its potential impacts on algae

Antarctica is not free from environmental pollutants although it is often perceived as the last pristine continent on Earth. Research stations represent one of the largest forms of anthropogenic activity and are the main source of locally derived contamination in Antarctica. Elevated levels of heavy metals such as copper (Cu), lead (Pb) and mercury (Hg) have been detected in Antarctica. Fuel combustion, accidental oil spills, waste incineration and sewage disposal are amongst the primary sources of heavy metal contaminants in Antarctica, besides natural sources such as animal excrements and volcanism. Studies on the impacts of heavy metals on biota in Antarctica have been focused mainly on invertebrates and cryptogams but not on algae. However, adverse impacts of heavy metals on sensitive algae may affect organisms at the higher trophic levels, and consequently disrupt Antarctic food chains. Heavy metals may be accumulated by algae and biomagnified through the food chain. The sensitivity and response of Antarctic algae to heavy metal toxicity have not been well studied. Robust toxicity protocols for the testing of the impacts of heavy metals on Antarctic algae need to be developed. This review aims to give an overview of the status of heavy metal pollution in Antarctica and its potential impacts on algae