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The Science of the Total Environment Feb 2022Methane, a potent greenhouse gas of global importance, has traditionally been considered as an end product of microbial methanogenesis of organic matter. Paradoxically,... (Review)
Review
Methane, a potent greenhouse gas of global importance, has traditionally been considered as an end product of microbial methanogenesis of organic matter. Paradoxically, growing evidence has shown that some microbes, such as cyanobacteria, algae, fungi, purple non-sulfur bacteria, and cryptogamic covers, produce methane in oxygen-saturated aquatic and terrestrial ecosystems. The non-methanogenesis process could be an important potential contributor to methane emissions. This systematic review summarizes the knowledge of microorganisms involved in the non-methanogenesis process and the possible mechanisms of methane formation. Cyanobacteria-derived methane production may be attributed to either demethylation of methyl phosphonates or linked to light-driven primary productivity, while algae produce methane by utilizing methylated sulfur compounds as possible carbon precursors. In addition, fungi produce methane by utilizing methionine as a possible carbon precursor, and purple non-sulfur bacteria reduce carbon dioxide to methane by nitrogenase. The microbial methane distribution from the non-methanogenesis processes in aquatic and terrestrial environments and its environmental significance to global methane emissions, possible mechanisms of methane production in each open water, water-to-air methane fluxes, and the impact of climate change on microorganisms are also discussed. Finally, future perspectives are highlighted, such as establishing more in-situ experiments, quantifying methane flux through optimizing empirical models, distinguishing individual methane sources, and investigating nitrogenase-like enzyme systems to improve our understanding of microbial methane emission from the non-methanogenesis process.
Topics: Carbon Dioxide; Cyanobacteria; Ecosystem; Methane; Nitrogenase
PubMed: 34740653
DOI: 10.1016/j.scitotenv.2021.151362 -
The Science of the Total Environment Feb 2022Manufactured silica nanoparticles are used worldwide in large volumes for a variety of applications. An exposure of environmental organisms is therefore likely, and... (Meta-Analysis)
Meta-Analysis Review
Manufactured silica nanoparticles are used worldwide in large volumes for a variety of applications. An exposure of environmental organisms is therefore likely, and several data on the ecotoxicology of silica nanoparticles to different organisms have been published in recent years. This systematic review compiles and assesses these studies, in order to analyse the sensitivity distribution across different organisms. On this basis, maximum acceptable environmental concentrations are suggested and potential environmental risks are discussed. 1429 papers were retrieved from the scientific literature (Scopus), the U.S. ECOTOX knowledge database. 63 studies were finally included in the review and appraised according to the nanoCRED criteria. A total of 219 ecotoxicological endpoints recorded in 38 species (7 taxonomic groups) were condensed into a species sensitivity distribution. The resulting concentration that is hazardous for a maximum of 5% of exposed species (HC05) is 130 μg/L, from which a PNEC of 30 μg/L is estimated by applying an assessment factor of 5. These concentrations are 1-3 orders of magnitudes above the concentrations modelled to occur in European aquatic ecosystems. Algae and bacteria have a comparatively low sensitivity to MSNP exposure, likely because their cell wall forms a protective barrier against nanoparticle exposure. Similarly, embryonic stages of fish also show a comparatively low sensitivity due to the protection from their chorion. However, the fish species Labeo rohita and Oncorhynchus mykiss are among the most sensitive species. The ecotoxicity of silica nanoparticles is linked to the number of hydroxyl groups on their surface, corresponding to findings from human toxicological studies. It is recommended that future ecotoxicological studies use explicit concentration-response designs, use proven biocide-free testing material, comparatively apply mass and surface area as exposure metrics, and provide important metainformation in the study report.
Topics: Animals; Aquatic Organisms; Cyprinidae; Ecosystem; Ecotoxicology; Humans; Nanoparticles; Risk Assessment; Silicon Dioxide; Water Pollutants, Chemical
PubMed: 34653448
DOI: 10.1016/j.scitotenv.2021.150893 -
Journal of Hazardous Materials Feb 2022Coastal wetlands are ecosystems lying between land and ocean and are subject to inputs of heavy metals (HMs) from terrestrial, oceanic and atmospheric sources. Although... (Review)
Review
Coastal wetlands are ecosystems lying between land and ocean and are subject to inputs of heavy metals (HMs) from terrestrial, oceanic and atmospheric sources. Although the study on HM pollution in coastal wetlands has been rapidly developing over the past three decades, systematic reviews are still unavailable. Here, by analyzing 3343 articles published between 1990 and 2019, we provided the first holistic systematic review of studies on HM pollution in coastal wetlands globally. The results showed a trend of rapid increases in publications in this field globally, especially over the past ten years. Trends varied greatly among coastal countries, and global trends were primarily driven by the US before 2000, and in China after 2010. We also found that mercury (Hg), cadmium (Cd), and copper (Cu) were the most widely studied HM elements globally, but patterns differed geographically, with Hg being most widely examined in the Americas, Cd in China and India, and lead (Pb) in the western Europe and Australia, respectively. Among different types of coastal wetlands, salt marshes, mangrove forests, and estuaries were the most widely studied, in contrast to seagrass beds and tidal flats. As for ecosystem components, soils/sediments and plants were most extensively investigated, while algae, microbes, and animals were much less examined. Our analysis further revealed rapid emergence of topics on anthropogenic sources, interactions with other anthropogenic environmental changes (climate change in particular), and control and remediation methodology in the literature in the recent ten years. Moving forward, we highlight that future studies are needed to i) better understand the impacts of HM pollution in less studied coastal wetland systems and species, ii) deepen current understanding of the biogeochemical behaviors of HMs under anthropogenic activities, iii) examine interactions with other anthropogenic environmental changes, iv) conceive ecological remediation (i.e., "ecoremediation" as compared to traditional physiochemical remediation and bioremediation) strategies, and v) develop advanced analysis instruments and methods. The perspectives we brought forward can help stimulate many new advances in this field.
Topics: Anthropogenic Effects; China; Ecosystem; Environmental Monitoring; Environmental Pollution; Geologic Sediments; Metals, Heavy; Wetlands
PubMed: 34600393
DOI: 10.1016/j.jhazmat.2021.127312 -
Current Problems in Cardiology Oct 2022Diabetes mellitus and insulin resistance are associated with an increased risk of cardiovascular disease (CVD) incidence and a higher rate of CVD-related death. In this... (Meta-Analysis)
Meta-Analysis Review
Diabetes mellitus and insulin resistance are associated with an increased risk of cardiovascular disease (CVD) incidence and a higher rate of CVD-related death. In this study, the effects of Arthrospira (Spirulina) a blue-green algae supplementation on biomarkers of glycemic control and glucose metabolism has been evaluated. PubMed, Scopus, and ISI Web of Science were searched systematically of English human subjects and PubMed for pre-clinical animal studies (rats and mice) from January 2008 until November 2020. The pooled weighted mean difference (MD) and its 95% confidence interval (CI) were calculated and pooled using a random-effect model. Seven clinical and 27 preclinical studies were included. Pooled results of the clinical studies showed that Arthrospira supplementation significantly reduced the fasting blood sugar (FBS): (0.63- 2.90-) 1.77-, total cholesterol (TC): (0.46- ، 4.61-) 2.54-, triglycerides (TG): (0.89- ، 6.54-) 3.71- and increased the high-density lipoprotein cholesterol (HDL-C): (3.86 ، 0.67) 2.27; however, Arthrospira was not significantly effective in terms of reducing the glycated hemoglobin A1c (HbA1C): (1.04 ، 2.23-) 0.59- and low-density lipoprotein cholesterol (LDL-C). Pooled results of preclinical studies showed that Arthrospira supplementation reduced FBS [-10.31 (-12.49, -8.13)] and HbA1C [-5.12 (-8.06, -2.19)] significantly in diabetic animals. Sub-group analysis of clinical studies showed that intervention duration less than 2 months [-2.52 (-4.37, -0.67)] and the dose less than 2 gram [-3.22 (-5.67, -0.76)] showed significant improvement in terms of reducing the FBS in humans. It can be concluded that Arthrospira can be considered as an effective FBS, TG, TC, and HDL-C adjusting nutraceutical agent for diabetes mellitus. Due to the differences in the results of clinical and animal studies in terms of HbA1c, more studies are needed for a definitive conclusion.
Topics: Animals; Biomarkers; Blood Glucose; Cardiovascular Diseases; Cholesterol, HDL; Diabetes Mellitus; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Glycemic Control; Humans; Mice; Microalgae; Rats; Spirulina; Triglycerides
PubMed: 34538515
DOI: 10.1016/j.cpcardiol.2021.100942 -
Journal of Medical Virology Dec 2021To systematically evaluate the effectiveness and safety of the SARS-CoV-2 vaccines currently undergoing clinical trials. (Review)
Review Meta-Analysis
OBJECTIVE
To systematically evaluate the effectiveness and safety of the SARS-CoV-2 vaccines currently undergoing clinical trials.
METHODS
PubMed, EMBASE, and Cochrane Library databases were searched to collect open human COVID-19 vaccines randomized controlled trials, without limiting the search time and language. The research papers collected in the above-mentioned databases were initially screened according to the title and abstract content and merged, and the repeated ones were removed. After reading the full text of the remaining research, the studies that did not meet the inclusion criteria were excluded, and finally, nine studies were obtained. After extracting the statistical data of adverse events in the study, load them into Review Manager for heterogeneity analysis.
RESULTS
The incidence of adverse reactions of inactivated virus vaccines, RNA vaccines, and adenovirus vector vaccines was higher than that of placebo. Common adverse reactions included pain, swelling, and fever at the injection site.
CONCLUSION
From the perspective of effectiveness, RNA vaccine > adenovirus vector vaccine > inactivated virus vaccine. From the perspective of safety, the incidence of adverse reactions of the three vaccines is higher than that of a placebo, and the incidence of adverse reactions of the adenovirus vector vaccine is higher.
Topics: Adenovirus Vaccines; COVID-19; COVID-19 Vaccines; Humans; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Vaccination; Vaccines, Inactivated; Vaccines, Synthetic
PubMed: 34264528
DOI: 10.1002/jmv.27203 -
International Journal of Clinical... Oct 2021Spirulina, a type of blue-green algae, is used as an adjuvant treatment of metabolic and inflammatory diseases. Evidence about the effects of spirulina on antioxidant... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Spirulina, a type of blue-green algae, is used as an adjuvant treatment of metabolic and inflammatory diseases. Evidence about the effects of spirulina on antioxidant system are conflicting. Thus, this quantitative review aimed to summarise the effects of spirulina administration on antioxidant status biomarkers.
METHODS
Systematic searches were conducted using the PubMed/Medline, Scopus, Web of Science and EMBASE, up to May 2021. Random effect analysis was applied to perform meta-analysis. Subgroup analyses and multivariate meta-regression were performed to find heterogeneity sources. Quality assessment was conducted using Cochrane Collaboration's tool. Trim and fill analysis were also carried out in case of the presence of publication bias.
RESULTS
A total of nine articles that enrolled 415 subjects were included in the present meta-analysis. Obtained findings exhibited that spirulina supplementation had marginal significant effect on total antioxidant capacity (TAC) (SMD = 0.49; 95% CI: -0.001, 0.98; P = .05) and superoxide dismutase (SOD) activity (SMD = 0.72; 95% CI: -0.03, 1.46; P = .06), while did not affect glutathione peroxidase (GPx) activity (SMD=0.27; 95% CI: -0.23, 0.77; P = .29).
CONCLUSIONS
Spirulina consumption may exert beneficial effects on enhancement of antioxidant system. A marginal significant increasing effect on TAC and SOD activity were found by spirulina administration. However, it did not affect GPx activity.
Topics: Antioxidants; Biomarkers; Dietary Supplements; Humans; Spirulina
PubMed: 34235823
DOI: 10.1111/ijcp.14618 -
Polysaccharides with Antitumor Effect in Breast Cancer: A Systematic Review of Non-Clinical Studies.Nutrients Jun 2021To review the effects of polysaccharides and their proposed mechanisms of action in breast cancer experimental models. Articles were selected by using PubMed,...
To review the effects of polysaccharides and their proposed mechanisms of action in breast cancer experimental models. Articles were selected by using PubMed, ScienceDirect, Scopus, and Medline, assessed from 1 May 2019 to 1 July 2020. The systematic review was registered in the International Prospective Register of Systematic Reviews (Prospero) under the number CRD42020169103. Most of the studies explore algae polysaccharides (43.2%), followed by mushrooms (13.5%), plants (13.5%), fruits (10.8%), fungus (2.7%), bacteria, (2.7%), and sea animals (2.7%). A total of 8.1% investigated only in vitro models, 62.1% evaluated only in vivo models, and 29.7% evaluated in vitro and in vivo models. The mechanism of action involves apoptosis, inhibition of cellular proliferation, angiogenesis, and antimetastatic effects through multiple pathways. Findings included here support further investigations on the anti-tumor effect of polysaccharides. Some polysaccharides, such as fucoidan and β-glucans, deserve detailed and structured studies aiming at translational research on breast tumors, since they are already used in the clinical practice of other proposals of human health.
Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Female; Humans; Polysaccharides; Publication Bias; Risk
PubMed: 34200897
DOI: 10.3390/nu13062008 -
The Science of the Total Environment Oct 2021Macrophytes have often been considered as a prospective tool for the elimination of cyanobacterial bloom, because they may produce chemical compounds that outcompete...
Macrophytes have often been considered as a prospective tool for the elimination of cyanobacterial bloom, because they may produce chemical compounds that outcompete bloom-forming cyanobacteria. However, a comprehensive, unbiased overview of evidence to support this is missing. Moreover, studies into the effects of individual macrophyte species have often used different methodologies and, thus, cannot be compared. Herein, we firstly carried out a systematic review of studies into the effects of macrophytes on the growth of bloom-forming cyanobacteria. Secondly, we carried out an experiment into the effects of aqueous and ethanol extracts from 19 macrophyte species on the growth of two of the most common cyanobacteria, Aphanizomenon gracile and Microcystis aeruginosa, using a uniform methodological approach. The systematic review revealed that most of the 69 macrophyte species previously studied have shown a combination of inhibitory, stimulatory, and neutral effects. In our own experiment, an inhibitory effect was exhibited only 15 times out of 532 experimental variants, specifically by Chara globularis, Ceratophyllum submersum, Elodea nuttallii, Hydrilla verticillata, Myriophyllum heterophyllum, M. spicatum, and Vallisneria americana. Put together, these results indicate that the practical application of chemical compounds produced by macrophytes to eliminate cyanobacterial bloom may have lower prospects than previously anticipated.
Topics: Aphanizomenon; Cyanobacteria; Hydrocharitaceae; Microcystis
PubMed: 34153748
DOI: 10.1016/j.scitotenv.2021.148413 -
Marine Drugs May 2021Air pollution has recently become a subject of increasing concern in many parts of the world. The World Health Organization (WHO) estimated that nearly 4.2 million early...
Air pollution has recently become a subject of increasing concern in many parts of the world. The World Health Organization (WHO) estimated that nearly 4.2 million early deaths are due to exposure to fine particles in polluted air, which causes multiple respiratory diseases. Algae, as a natural product, can be an alternative treatment due to potential biofunctional properties and advantages. This systematic review aims to summarize and evaluate the evidence of metabolites derived from algae as potential anti-inflammatory agents against respiratory disorders induced by atmospheric particulate matter (PM). Databases such as Scopus, Web of Science, and PubMed were systematically searched for relevant published full articles from 2016 to 2020. The main key search terms were limited to "algae", "anti-inflammation", and "air pollutant". The search activity resulted in the retrieval of a total of 36 publications. Nine publications are eligible for inclusion in this systematic review. A total of four brown algae (, , and ) with phytosterol, polysaccharides and polyphenols were reported in the nine studies. The review sheds light on the pathways of particulate matter travelling into respiratory systems and causing inflammation, and on the mechanisms of actions of algae in inhibiting inflammation. Limitations and future directions are also discussed. More research is needed to investigate the potential of algae as anti-inflammatory agents against PM in in vivo and in vitro experimental models, as well as clinically.
Topics: Air Pollutants; Animals; Anti-Inflammatory Agents; Humans; Particulate Matter; Phaeophyceae; Respiratory Tract Diseases
PubMed: 34070821
DOI: 10.3390/md19060317 -
Current Topics in Medicinal Chemistry 2021Nutraceuticals are food or component of food that do not only promote health but also help in recovering and combating health disorders. Algae are microorganisms that...
Nutraceuticals are food or component of food that do not only promote health but also help in recovering and combating health disorders. Algae are microorganisms that are used as supplements used in treating health disorders. They are rich in essential fatty acids, antioxidant pigments, and other micronutrients. These algae are gaining importance as functional components in the green synthesis of metal nanoparticles and applications in fabrics incorporated antimicrobial agents and pharmaceuticals. The present review focus on the distinctive algal components that are beneficial in biomedical applications. It also focuses on the research techniques to enrich the macronutrients and micronutrients by altering growth conditions and susceptible nutritional factors. A diagram model for a systematic review is utilized for this search. The research is conducted through the following databases: PubMed, Web of Science, Scopus, and Science Direct. Results: Here in this review, current reviewers put forward the importance of microalgae and other algae as alternative marine nutrient sources of dietary supplements for human consumption. In this context, extrinsic and intrinsic environmental parameter manipulative studies by eminent research groups to enhance the nutrient composition of these marine creatures are focused on in this study. Some costeffective approach-based techniques for industrial output have also been manifested. The role of algae as bio-inspired material for the production of biosynthetic metal nanoparticles, water-soluble polymers, bioplastic, antimicrobials, antifouling agents has been incurred as research interests in the past decades. In spite of being so impressive as nutraceuticals and bio-inspired material components, research gaps still exist. The purpose of the manuscript is to cover such gaps and show a new paradigm of biomedical applications.
Topics: Biomedical Research; Biomimetic Materials; Dietary Supplements; Humans; Microalgae
PubMed: 34030613
DOI: 10.2174/1568026621666210524095925