scholarly journals Bioremediation of Per- and Poly-Fluoroalkyl Substances (PFAS) by Synechocystis sp. PCC 6803: A Chassis for a Synthetic Biology Approach

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1300
Author(s):  
Francesca Marchetto ◽  
Marco Roverso ◽  
Davide Righetti ◽  
Sara Bogialli ◽  
Francesco Filippini ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Industrialized Countries ◽  
Long Term Effects ◽  
High Concentration ◽  
Treatment Processes ◽  
Batch Systems ◽  
Wide Range ◽  
Photosynthetic Organism ◽  
Synechocystis Sp

One of the main concerns in industrialized countries is represented by per- and poly-fluoroalkyl substances (PFAS), persistent contaminants hardly to be dealt with by conventional wastewater treatment processes. Phyco-remediation was proposed as a green alternative method to treat wastewater. Synechocystis sp. PCC6803 is a unicellular photosynthetic organism candidate for bioremediation approaches based on synthetic biology, as it is able to survive in a wide range of polluted waters. In this work, we assessed the possibility of applying Synechocystis in PFAS-enriched waters, which was never reported in the previous literature. Respirometry was applied to evaluate short-term toxicity of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), which did not affect growth up to 0.5 and 4 mg L−1, respectively. Continuous and batch systems were used to assess the long-term effects, and no toxicity was highlighted for both compounds at quite high concentration (1 mg L−1). A partial removal was observed for PFOS and PFOA, (88% and 37%, with removal rates of about 0.15 and 0.36 mg L−1 d−1, respectively). Measurements in fractionated biomass suggested a role for Synechocystis in the sequestration of PFAS: PFOS is mainly internalized in the cell, while PFOA is somehow transformed by still unknown pathways. A preliminary bioinformatic search gave hints on transporters and enzymes possibly involved in such sequestration/transformation processes, opening the route to metabolic engineering in the perspective application of this cyanobacterium as a new phyco-remediation tool, based on synthetic biology.

Effects of long-term ionic and osmotic stress conditions on photosynthesis in the cyanobacterium Synechocystis sp. PCC 6803

2005 ◽  
Vol 32 (9) ◽  
pp. 807 ◽  
Author(s):  
Saowarath Jantaro ◽  
Paula Mulo ◽  
Tove Jansén ◽  
Aran Incharoensakdi ◽  
Pirkko Mäenpää
Keyword(s):  
Osmotic Stress ◽  
Stress Component ◽  
D1 Protein ◽  
Long Term Effects ◽  
High Concentration ◽  
High Concentrations ◽  
Synechocystis Sp ◽  
Halotolerant Cyanobacterium ◽  
Pcc 6803

Salinity is considered to be one of the most severe problems in worldwide agricultural production, but the published investigations give contradictory results of the effect of ionic and osmotic stresses on photosynthesis. In the present study, long-term effects of both ionic and osmotic stresses, especially on photosynthesis, were investigated using the moderately halotolerant cyanobacterium Synechocystis sp. PCC 6803. Our results show that the PSII activity and the photosynthetic capacity tolerated NaCl but a high concentration of sorbitol completely inhibited both activities. In line with these results, we show that the amount of the D1 protein of PSII was decreased under severe osmotic stress, whereas the levels of PsaA / B and NdhF3 proteins remained unchanged. However, high concentrations of sorbitol stress led to a drastic decrease of both psbA (encoding D1) and psaA (encoding PsaA) transcripts, suggesting that severe osmotic stress may abolish the tight coordination of transcription and translation normally present in bacteria, at least in the case of the psaA gene. Taken together, our results indicate that the osmotic stress component is more detrimental to photosynthesis than the ionic one and, furthermore, under osmotic stress, the D1 protein appears to be the target of this stress treatment.

Long-term Effects of Triazol Growth Regulators on Stem Elongation of Rhododendron and Kalmia

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 436E-436
Author(s):  
Martin P.N. Gent
Keyword(s):  
Dose Response ◽  
Growth Regulator ◽  
Stem Elongation ◽  
Spray Application ◽  
Long Term Effects ◽  
Potted Plants ◽  
Response Coefficient ◽  
Wide Range ◽  
Second Year

The persistence of effects of paclobutrazol or uniconazol on stem elongation was determined for several years after large-leaf Rhododendron and Kalmia latifolia were treated with a single-spray application of these triazol growth-regulator chemicals. Potted plants were treated in the second year from propagation, and transplanted into the field in the following spring. The elongation of stems was measured in the year of application and in the following 2 to 4 years. Treatments with a wide range of doses were applied in 1991, 1992, or 1995. For all except the most-dilute applications, stem elongation was retarded in the year following application. At the highest doses, stem growth was inhibited 2 years following application. The results could be explained by a model of growth regulator action that assumed stem elongation was inversely related to amount of growth regulator applied. The dose response coefficient for paclobutrazol was less than that for uniconazol. The dose that inhibited stem elongation one-half as much as a saturating dose was about 0.5 and 0.05 mg/plant, for paclobutrazol and uniconazol, respectively. The dose response coefficient decreased exponentially with time after application, with an exponential time constant of about 2/year. The model predicted a dose of growth regulator that inhibited 0.9 of stem elongation immediately after application would continue to inhibit 0.5 of stem elongation in the following year.

Long-term effects of manure application on grain yield under different cropping systems and ecological conditions in China

2008 ◽  
Vol 147 (1) ◽  
pp. 31-42 ◽  
Author(s):  
H. ZHANG ◽  
M. XU ◽  
F. ZHANG
Keyword(s):  
Grain Yield ◽  
Cropping Systems ◽  
Long Term Effects ◽  
Manure Application ◽  
Organic C ◽  
Wide Range ◽  
Long Term Experiments ◽  
Continuous Maize ◽  
Yield Trends

SUMMARYRice (Oryza sativaL.), wheat (Triticum aestivumL.) and maize (Zea maysL.) are the main crops grown in China. Applying organic manures is an important practice in sustaining soil fertility and agricultural productivity in these cropping systems. The current paper presents the effects of manure application on grain yields in nine long-term experiments that consist of one continuous maize, four wheat–maize and four rice-based cropping systems across a wide range of agro-ecological regions in China. The study shows that regular manure application can increase soil organic carbon (SOC) and grain yield across all the sites. Overall, regular use of manure results in larger increases in SOC in the maize and wheat–maize systems than in the rice-based systems. Application of manure tends to increase the grain yield in the maize and wheat–maize systems during the final years, but increases the grain yield in the rice-based systems during the initial years of the long-term experiments. There is only one site that shows significant improvement in the yield trend in association with the application of manure. The effects of manure on yield trends are probably determined by the initial yield and/or the ‘organic C effect’ that may cause gradual improvements in SOC and soil physical properties.

scholarly journals The Effectiveness of Employment Vouchers: A Simple Approach

2000 ◽  
Vol 1 (4) ◽  
pp. 385-419 ◽  
Author(s):  
J. Michael Orszag ◽  
Dennis J. Snower
Keyword(s):  
Optimal Policy ◽  
Policy Design ◽  
Unemployment Benefits ◽  
Government Budget ◽  
Long Term Effects ◽  
Short Term ◽  
Wide Range ◽  
The Government ◽  
Hiring And Firing

Abstract This paper explores the optimal design of subsidies for hiring unemployed workers (`employment vouchers' for short) in the context of a simple dynamic model of the labour market. Focusing on the short-term and long-term effects of the vouchers on employment and unemployment, the analysis shows how the optimal policy depends on the rates of hiring and firing, and on the problems of displacement and deadweight. It also examines the roles of the government budget constraint and of the level of unemployment benefits in optimal policy design. We calibrate the model and evaluate the effectiveness of employment vouchers in reducing unemployment for a wide range of feasible parameters.

Long-Term Effects in Models with Temporal Dependence

2016 ◽  
Vol 24 (2) ◽  
pp. 243-262 ◽  
Author(s):  
Laron K. Williams
Keyword(s):  
Conflict Behavior ◽  
Binary Outcomes ◽  
International Studies ◽  
Long Term Effects ◽  
Temporal Dependence ◽  
Parliamentary Democracies ◽  
Explanatory Variables ◽  
Wide Range ◽  
Repeated Events

A dominant trend in models with binary outcomes is to control for unmodeled duration dependence by including temporal dependence variables. A second, distinct trend is to interpret both the short- and long-term effects of explanatory variables in autoregressive models. While the first trend is nearly ubiquitous in models with binary outcomes, the second trend has yet to be applied consistently beyond models with continuous outcomes. While scholars use temporal splines and cubic polynomials to model the underlying hazard rate, they have neglected the fact that this causes the explanatory variables to have a long-term effect (LTE) by modifying the future values of the temporal dependence variables. In this article, I propose a simple technique that estimates a wide range of probabilistic LTEs in models with temporal dependence variables. These effects can range from simple LTEs for a one-time change in an explanatory variable to more complex scenarios where effects change in magnitude with time and compound across repeated events. I then replicate Clare's (2010, Ideological fractionalization and the international conflict behavior of parliamentary democracies.International Studies Quarterly54:965–87) examination of the influence of government fractionalization on conflict behavior to show that failing to interpret the results within the context of temporal dependence underestimates the total impact of fractionalization by neglecting LTEs.

scholarly journals The role of oxidative stress, inflammation and acetaminophen exposure from birth to early childhood in the induction of autism

2017 ◽  
Vol 45 (2) ◽  
pp. 407-438 ◽  
Author(s):  
William Parker ◽  
Chi Dang Hornik ◽  
Staci Bilbo ◽  
Zoie E. Holzknecht ◽  
Lauren Gentry ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Early Childhood ◽  
Early Development ◽  
Long Term Effects ◽  
Small Children ◽  
Factors Associated ◽  
Wide Range ◽  
And Oxidative Stress

The wide range of factors associated with the induction of autism is invariably linked with either inflammation or oxidative stress, and sometimes both. The use of acetaminophen in babies and young children may be much more strongly associated with autism than its use during pregnancy, perhaps because of well-known deficiencies in the metabolic breakdown of pharmaceuticals during early development. Thus, one explanation for the increased prevalence of autism is that increased exposure to acetaminophen, exacerbated by inflammation and oxidative stress, is neurotoxic in babies and small children. This view mandates extreme urgency in probing the long-term effects of acetaminophen use in babies and the possibility that many cases of infantile autism may actually be induced by acetaminophen exposure shortly after birth.

scholarly journals Ecotoxicity of Wastewater from Medical Facilities: A Review

2018 ◽  
Vol 49 (1) ◽  
pp. 26-31
Author(s):  
A. Cidlinová ◽  
Z. Wittlingerová ◽  
M. Zimová ◽  
T. Chrobáková ◽  
A. Petruželková
Keyword(s):  
Human Health ◽  
Complex Mixture ◽  
Aquatic Organisms ◽  
Hazardous Substances ◽  
Health It ◽  
Long Term Effects ◽  
Low Concentrations ◽  
Wide Range ◽  
Medical Facilities

Abstract Wastewater from medical facilities contains a wide range of chemicals (in particular pharmaceuticals, disinfectants, heavy metals, contrast media, and radionuclides) and pathogens, therefore it constitutes a risk to the environment and human health. Many micropollutants are not efficiently eliminated during wastewater treatment and contaminate both surface water and groundwater. As we lack information about the long-term effects of low concentrations of micropollutants in the aquatic environment, it is not possible to rule out their adverse effects on aquatic organisms and human health. It is, therefore, necessary to focus on the evaluation of chronic toxicity in particular when assessing the environmental and health risks and to develop standards for the regulation of hazardous substances in wastewater from medical facilities on the basis of collected data. Wastewater from medical facilities is a complex mixture of many compounds that may have synergetic, antagonistic or additive effects on organisms. To evaluate the influence of a wide range of pollutants contained in the effluents from medical facilities on aquatic ecosystems, it is necessary to determine their ecotoxicity.

Children and Political Violence: An Overview

1994 ◽  
Vol 17 (4) ◽  
pp. 669-674 ◽  
Author(s):  
Ed Cairns
Keyword(s):  
Political Violence ◽  
Special Section ◽  
Stress And Coping ◽  
Cross Cultural ◽  
Cultural Work ◽  
Future Research ◽  
Long Term Effects ◽  
Wide Range ◽  
And Coping

The papers presented in this special section provide an introduction to the area of research on the effects of political violence on children. The articles cover a wide range of topics from the well-researched question of stress and coping to the less often investigated questions of the development of aggression, the long-term effects of political violence, and the evaluation of attempts at reconciliation. In addition, they represent those geographical areas which at present dominate work in this area the Middle East, Northern Ireland, and South Africa. They also illustrate emerging debates concerning resilience versus vulnerability and the effectiveness of outsiders versus insiders as investigators. The research reported here also points to the need for more cross-cultural work. Finally, it is argued that there is a need to understand the collective nature of political violence. This has implications not only for future research methods but, more importantly, for the development of a theoretical basis that is needed for work in this area.

Long-term effects of engineered nanoparticles on enzyme activity and functional bacteria in wastewater treatment plants

2015 ◽  
Vol 72 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Xiong Zheng ◽  
Haining Huang ◽  
Yinglong Su ◽  
Yuanyuan Wei ◽  
Yinguang Chen
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Engineered Nanoparticles ◽  
Ammonia Oxidizing Bacteria ◽  
Long Term Effects ◽  
Gene Expressions ◽  
Key Enzymes ◽  
Functional Bacteria ◽  
Wide Range

Abstract The pervasive use of engineered nanoparticles (NPs) in a wide range of fields raises concerns about their potential environmental impacts. Previous studies confirmed that some NPs had already entered wastewater treatment plants (WWTPs). Wastewater nutrient removal depends on the metabolisms of activated sludge bacteria and their related key enzymes. Therefore, this study compared the possible influences of Al2O3, SiO2, TiO2, and ZnO NPs on the key enzymes activities and microbial community structures involved in wastewater treatment facilities. It was found that long-term exposure to these NPs significantly affected the microbial communities and changed the relative abundances of key functional bacteria, such as ammonia-oxidizing bacteria. Also, the gene expressions and catalytic activities of essential enzymes, such as ammonia monooxygenase, nitrite oxidoreductase, nitrate reductase, and nitrite reductase, were decreased, which finally resulted in a lower efficiency of biological nitrogen removal.

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