Effect of naphthalene and aqueous crude oil extracts on the green flagellate Chlamydomonas angulosa. II. Photosynthesis and the uptake and release of naphthalene

1975 ◽  
Vol 53 (2) ◽  
pp. 118-126 ◽  
Author(s):  
C. Soto ◽  
J. A. Hellebust ◽  
T. C. Hutchinson
Keyword(s):  
Crude Oil ◽  
Photosynthetic Capacity ◽  
Open Systems ◽  
Complete Loss ◽  
Original Medium ◽  
Rate Of Recovery ◽  
Green Flagellate ◽  
Saturated Media ◽  
Closed Systems ◽  
Actual Loss

Comparisons have been made of the effects of crude oil extracts and naphthalene on the photosynthesis of the alga Chlamydomonas angulosa. The addition of the hydrocarbon naphthalene to C. angulosa cultures causes an immediate and almost complete loss of photosynthetic capacity. When cells that have been incubated in closed systems containing naphthalene-saturated media are transferred to open systems which allow loss by volatilization of naphthalene, the rate of recovery of photosynthesis is inversely proportional to the length of incubation in the closed system with naphthalene. Incubation of cells in open systems with media containing aqueous crude oil extracts has no significant effect on their photosynthetic capacity as compared with that of cells incubated in control media. However, the photosynthetic capacity is decreased when cells are incubated in closed systems with media containing aqueous crude oil extracts. This is followed by a gradual recovery with time of incubation after treatment in the closed systems.Experiments using labelled naphthalene indicate that C. angulosa cells accumulate naphthalene from the medium in closed systems for up to 7 days. When such cells are transferred to fresh media not containing naphthalene, there is an almost immediate loss of the aromatic hydrocarbon from the cells. However, when cells are retained in their original medium after opening the culture system to allow naphthalene to escape, the decrease in naphthalene content per cell appears dependent upon resumption of cell division and occurs in a stepwise manner, which suggests cell retention rather than an actual loss of naphthalene to the medium.

Effect of naphthalene and aqueous crude oil extracts on the green flagellate Chlamydomonas angulosa. I. Growth

1975 ◽  
Vol 53 (2) ◽  
pp. 109-117 ◽  
Author(s):  
C. Soto ◽  
J. A. Hellebust ◽  
T. C. Hutchinson ◽  
T. Sawa
Keyword(s):  
Crude Oil ◽  
Closed System ◽  
Generation Time ◽  
Open Systems ◽  
Crude Oils ◽  
Lag Phase ◽  
Aqueous Extracts ◽  
System A ◽  
Green Flagellate ◽  
Closed Systems

Spills of crude oil and various refined fractions are an increasing threat to organisms both in marine and in freshwater situations. The present study is concerned with the effects of aqueous crude oil extracts and naphthalene on one organism, the green flagellate Chlamydomonas angulosa, grown under controlled conditions. Tests were carried out under conditions allowing relatively free evaporation and volatilization of the hydrocarbons (open systems) and in closed systems in which hydrocarbon loss was minimized (closed systems).In open systems, 61% of the Chlamydomonas angulosa cells were killed when saturated naphthalene was initially present in the medium. The generation time of the survivors was, however, the same as the controls. In a closed system a much higher percentage of the cells was killed, but a shorter generation time was observed when growth resumed. A prolonged lag phase was characteristic of all naphthalene treatments.The effect of aqueous extracts of crude oils was also tested using different crude oils, fresh and aged extracts, as well as open and closed systems. Extracts were almost always inhibitory, but the effects were less severe than those obtained with naphthalene. The possible implications are discussed.

Effect of naphthalene and aqueous crude-oil extracts on the green flagellate Chlamydomonas angulosa. VI. Phosphate uptake and retention

1985 ◽  
Vol 63 (4) ◽  
pp. 829-833 ◽  
Author(s):  
T. C. Hutchinson ◽  
C. Soto ◽  
J. A. Hellebust
Keyword(s):  
Crude Oil ◽  
Phosphate Uptake ◽  
Culture Media ◽  
Large Fraction ◽  
Basal Medium ◽  
Atomic Ratio ◽  
Net Uptake ◽  
Green Flagellate ◽  
Saturated Media ◽  
Reactive Phosphorus

Chlamydomonas angulosa when grown in normal Bold's basal medium (BBM) (1.7 mM Pi) has a very high cell P content (120 fg-at. P∙cell−1) and low C: P atomic ratio (35: 1) and is only able to show net Pi uptake in media with Pi concentrations higher than 0.1 mM when grown in the light. The presence of light enhances net phosphate uptake or decreases net phosphate loss under all external Pi concentrations. Cells transferred to low-Pi media will, however, grow rapidly while reducing their cell P to almost 1/10 of the initial level, indicating that most of the cell P in cells grown in high-P media represents reserve P, probably in the form of polyphosphates. The presence of naphthalene and crude-oil components in the culture media decreases net uptake of Pi at high external Pi concentrations and increases the rate of Pi loss at low external concentrations. Naphthalene present at 100% saturation level in BBM causes rapid loss of a large fraction of cell P under all conditions tested. The phosphorus lost appears as reactive phosphorus in the medium, suggesting that cell polyphosphates are rapidly converted to Pi, which then leaks out of the cells in response to the presence of saturating naphthalene concentrations in the medium. BBM with 50% naphthalene saturation causes much less loss of cell P under most of the incubation conditions, and net uptake can take place at the highest external Pi concentrations tested in the light. Media saturated with crude oil are even less effective than 50% naphthalene saturated media in causing P efflux, or in reducing net Pi uptake, although at low external P concentrations, uptake of P is decreased compared with the control.

Effect of naphthalene and aqueous crude-oil extracts on the green flagellate Chlamydomonas angulosa. VII. Nitrate and methylamine uptake and retention

1985 ◽  
Vol 63 (4) ◽  
pp. 834-840 ◽  
Author(s):  
J. A. Hellebust ◽  
C. Soto ◽  
T. C. Hutchinson
Keyword(s):  
Crude Oil ◽  
Nitrate Uptake ◽  
Prolonged Exposure ◽  
Basal Medium ◽  
Transport Activity ◽  
Uptake Capacity ◽  
Short Term ◽  
Initial Uptake Rate ◽  
Green Flagellate ◽  
Saturated Media

Chlamydomonas angulosa grows equally well on nitrate and ammonium as sources of nitrogen. The presence of ammonium decreases nitrate uptake by less than 10% in short-term experiments. The presence of nitrate has no significant effect on short-term uptake of the ammonium analogue methylamine. Cells grown in nitrate media possess considerable methylamine uptake capacity during early exponential growth. This uptake capacity falls rapidly as the cells enter the declining growth phase. When cells are transferred to nitrogen-deficient media, the uptake capacity for methylamine increases threefold to fourfold in 24 h. The half-saturation constants (Km) for nitrate and methylamine uptake of this alga are 0.4 mM and 90 μM, respectively. When C. angulosa cells are transferred from control Bolds basal medium (BBM) to 50% naphthalene saturated or aqueous crude oil saturated media, the initial uptake rate for nitrate increases by a factor of two or decreases by a factor of one-third, respectively, as compared with that of cells transferred to control BBM. However, cells incubated in closed incubation systems with naphthalene or aqueous crude oil saturated media for 3 days lose nitrate when resuspended in control media. Cells transferred to media containing naphthalene up to 20% saturation show no immediate decrease in methylamine transport, while higher naphthalene concentrations cause an immediate decrease in transport activity. However, cells incubated in 50% naphthalene saturated media in a closed system for 2–4 h actually show increased methylamine transport activity when the incubation system is opened to allow escape of the hydrocarbon. Prolonged exposure to 50% naphthalene saturated media, however, causes progressive loss of transport activity.

Expertise as a Form of Knowledge: A Response to Quast

2020 ◽  
Vol 42 (2) ◽  
pp. 431-442
Author(s):  
Steve Fuller
Keyword(s):  
Social Epistemology ◽  
Open Systems ◽  
Epistemic Standard ◽  
Closed Systems ◽  
The Difference

Abstract Christian Quast has presented what he describes as a ‘role-functional’ account of expertise as a form of knowledge that purports to take into account prior discussions within recent analytic social epistemology and allied fields. I argue that his scrupulousness results in a confused version of the role-functional account, which I try to remedy by presenting a ‘clean’ account that clearly distinguishes such an account from what Quast calls a ‘competence-driven’ one. The key point of my account is that ‘competence’ pertains to knowledge in closed systems and ‘expertise’ in open systems. I observe that the invocation of ‘reliability’ as an epistemic standard simply serves to confuse the difference between the competence-driven and role-functional accounts.

6. Such quantities of sand

2014 ◽  
pp. 102-117
Author(s):  
Christopher Hall
Keyword(s):  
Carbon Dioxide ◽  
Circular Economy ◽  
Carbon Dioxide Emissions ◽  
Energy Supply ◽  
Open Systems ◽  
Human History ◽  
Material Flows ◽  
Material Resources ◽  
World Energy ◽  
Closed Systems

‘Such quantities of sand’ looks at sustainability and considers three features of the global materials system that need fixing: carbon dioxide emissions, world energy supply, and finite material resources. All societies, however diverse, are comprehensively and universally dependent on material artefacts. The scale of global material flows is enormous, and now greater than for all of human history. In a finite world, there are limits and so it is wise, on some timescale, to favour a circular economy of closed systems (repair, re-use, recycle) over open systems (extract, make, use, discard). Whatever else we do, it helps if we reduce the rate of flow of materials through the economy (use less, use longer).

Investigating the Mixing Efficiencies of Liquid-to-Liquid Chemical Injection Manifolds for Aquatic Invasive Species Management

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Thomas J. Zolper ◽  
Aaron R. Cupp ◽  
David L. Smith
Keyword(s):  
Invasive Species ◽  
Large Scale ◽  
Open Systems ◽  
Mixing Time ◽  
Water Injection ◽  
The United States ◽  
Aquatic Invasive Species ◽  
Chemical Treatments ◽  
Invasive Organisms ◽  
Closed Systems

Aquatic invasive species (AIS) have spread throughout the United States via major rivers and tributaries. Locks and dams positioned along affected waterways, specifically lock chambers, are being evaluated as potential management sites to prevent further expansion into new areas. Recent research has shown that infusion of chemicals (e.g., carbon dioxide) into water can block or kill several invasive organisms and could be a viable option at navigational structures such as lock chambers because chemical infusion would not interfere with vessel passage or lock operation. Chemical treatments near lock structures will require large-scale fluid-mechanic systems and significant energy. Mixing must extend to all stagnation regions within a lock structure to prevent the passage of an invasive fish. This work describes the performance of both wall- and floor-based CO2-infused-water to water injection manifolds targeted for lock structures in terms of mixing time, mixing homogeneity, injection efficiency, and operational power requirements. Both systems have strengths and weaknesses so selection recommendations are given for applications such as open systems and closed systems.

scholarly journals Open Prebiotic Environments Drive Emergent Phenomena and Complex Behavior

Life ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
Nathaniel Wagner ◽  
David Hochberg ◽  
Enrique Peacock-Lopez ◽  
Indrajit Maity ◽  
Gonen Ashkenasy
Keyword(s):  
Open Systems ◽  
Complex Behavior ◽  
Working Models ◽  
Emergent Phenomena ◽  
Systems Chemistry ◽  
Wide Range ◽  
Closed Systems ◽  
Prebiotic Environments ◽  
Far From Equilibrium ◽  
And Function

We have been studying simple prebiotic catalytic replicating networks as prototypes for modeling replication, complexification and Systems Chemistry. While living systems are always open and function far from equilibrium, these prebiotic networks may be open or closed, dynamic or static, divergent or convergent to a steady state. In this paper we review the properties of these simple replicating networks, and show, via four working models, how even though closed systems exhibit a wide range of emergent phenomena, many of the more interesting phenomena leading to complexification and emergence indeed require open systems.

Surface flow of granular materials: model and experiments in heap formation

2001 ◽  
Vol 441 ◽  
pp. 255-264 ◽  
Author(s):  
D. V. KHAKHAR ◽  
ASHISH V. ORPE ◽  
PETER ANDRESÉN ◽  
J. M. OTTINO
Keyword(s):  
Flow Rate ◽  
Open Systems ◽  
Static Friction ◽  
Surface Flow ◽  
Two Dimensional ◽  
Surface Flows ◽  
Industrial Practice ◽  
Natural Systems ◽  
Closed Systems ◽  
Good Agreement

Granular surface flows are important in industrial practice and natural systems, but the understanding of such flows is at present incomplete. We present a combined theoretical and experimental study of quasi-two-dimensional heap formation by pouring particles continuously at a point. Two cases are considered: open systems and closed systems. Experimental results show that the shear rate in the flowing layer is nearly independent of the mass flow rate, and the angle of static friction at the bed–layer interface increases with flow rate. Predictions of the model for the flowing layer thickness and interface angles are in good agreement with experiments.

E-Cigarettes: Policy Options and Legal Issues Amidst Uncertainty

2015 ◽  
Vol 43 (S1) ◽  
pp. 23-26 ◽  
Author(s):  
Nancy Kaufman ◽  
Margaret Mahoney
Keyword(s):  
Smoking Cessation ◽  
Propylene Glycol ◽  
Open System ◽  
Closed System ◽  
Open Systems ◽  
Delivery Systems ◽  
Legal Issues ◽  
Policy Options ◽  
Electronic Nicotine Delivery Systems ◽  
Closed Systems

E-cigarettes, sometimes referred to as ENDS (Electronic Nicotine Delivery Systems), include a broad range of products that deliver nicotine via heating and aerosolization of the drug. ENDS come in a variety of forms, but regardless of form generally consist of a solution containing humectant (e.g., propylene glycol or glycerol), flavorings, and usually nicotine (some solutions do not contain nicotine); a battery-powered coil that heats the solution into an aerosol (usually referred to as vapor) in an atomizing chamber; and a mouthpiece through which the user draws the vapor into the mouth and lungs. The devices may be closed systems containing prefilled cartridges, or open systems, where the user manually refills a 1-2 ml. tank with solution. What started as closed-system cigarette-shaped devices marketed as an adjunct for smoking cessation, has transitioned rapidly to literally thousands of hip and funky-designed open-system hookah pens, vape pens, and modifiable devices. For younger people, these forms are the “in” thing, while traditional cigarette-shaped devices are “out.”

Volatility of Antioxidants and Antiozonants II. Effect on Rubber Testing

1965 ◽  
Vol 38 (1) ◽  
pp. 134-139 ◽  
Author(s):  
R. B. Spacht ◽  
W. S. Hollingshead ◽  
H. L. Bullard ◽  
D. C. Wills
Keyword(s):  
Vapor Pressure ◽  
Open Systems ◽  
Accelerated Aging ◽  
Series Data ◽  
Oxygen Absorption ◽  
Accelerated Tests ◽  
Oxygen Bomb ◽  
Closed Systems

Abstract In the first paper of this series data were presented on the volatility and vapor pressure of eight antioxidants. The present work attempts to show how volatility-affects the performance of an antioxidant, particularly in accelerated aging tests. The usual accelerated tests are of two types: those using closed systems such as the air bomb, the oxygen bomb, and oxygen absorption, and those using open systems such as air oven aging and creep.

Sign in / Sign up

Export Citation Format

Share Document