Analysis of the Response of Hypolimnetic Phytoplankton in Continuous Culture to Increased Light or Phosphorus Using Track Autoradiography

1980 ◽  
Vol 37 (3) ◽  
pp. 434-441 ◽  
Author(s):  
R. Knoechel ◽  
F. deNoyelles Jr.
Keyword(s):  
Continuous Culture ◽  
Carbon Fixation ◽  
Common Species ◽  
Total Carbon ◽  
Experimental Lakes Area ◽  
Phosphorus Enrichment ◽  
Species Response ◽  
Ankistrodesmus Falcatus ◽  
Wide Range ◽  
Track Autoradiography

Phytoplankton from the hypolimnetic biomass peak in Lake 266SW (Experimental Lakes Area, northwestern Ontario) was subjected to conditions of increased light or phosphorus in continuous culture. Phosphorus enrichment increased total carbon fixation 16% relative to the control; however, the particulate fraction was initially depressed and the phytoplankton biomass was less than 2% greater after 10 d. The high light culture displayed 21% higher final biomass despite a 13% decline in total carbon fixation which was primarily due to reduced extracellular release. The 21 most common species demonstrated a wide range of positive and negative biomass responses to the experimental perturbations; however, the three dominant chrysophyte species all responded positively to higher light. Detection of population biomass changes provided a direct and accurate means of quantifying perturbation effects provided the species response was stable over several days. Measurement of carbon uptake rates of species through track autoradiography provided the additional sensitivity and temporal resolution needed to monitor low level or variable responses. Synedra radians exhibited a lengthy lag period before demonstrating a strong positive response to phosphorus enrichment, while Dinobryon sertularia shifted from neutral to strongly negative and then strongly positive within a 3-d period. These results illustrate the inadequacy of short-term bioassays for the prediction of long-term perturbation effects.Key words: growth rate, primary production, Ankistrodesmus falcatus, Dinobryon sertularia, Synedra radians

scholarly journals Phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in continuous culture

1972 ◽  
Vol 127 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. G. Bolton ◽  
A. C. R. Dean
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Continuous Culture ◽  
Activity Profile ◽  
Glucose Effect ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Wide Range ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

1. Phosphatase synthesis was studied in Klebsiella aerogenes grown in a wide range of continuous-culture systems. 2. Maximum acid phosphatase synthesis was associated with nutrient-limited, particularly carbohydrate-limited, growth at a relatively low rate, glucose-limited cells exhibiting the highest activity. Compared with glucose as the carbon-limiting growth material, other sugars not only altered the activity but also changed the pH–activity profile of the enzyme(s). 3. The affinity of the acid phosphatase in glucose-limited cells towards p-nitrophenyl phosphate (Km 0.25–0.43mm) was similar to that of staphylococcal acid phosphatase but was ten times greater than that of the Escherichia coli enzyme. 4. PO43−-limitation derepressed alkaline phosphatase synthesis but the amounts of activity were largely independent of the carbon source used for growth. 5. The enzymes were further differentiated by the effect of adding inhibitors (F−, PO43−) and sugars to the reaction mixture during the assays. In particular, it was shown that adding glucose, but not other sugars, stimulated the rate of hydrolysis of p-nitrophenyl phosphate by the acid phosphatase in carbohydrate-limited cells at low pH values (<4.6) but inhibited it at high pH values (>4.6). Alkaline phosphatase activity was unaffected. 6. The function of phosphatases in general is discussed and possible mechanisms for the glucose effect are outlined.

scholarly journals First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

2018 ◽  
Author(s):  
Bhavya P. Sadanandan ◽  
Jang Han Lee ◽  
Ho Won Lee ◽  
Jae Joong Kaang ◽  
Jae Hyung Lee ◽  
...  
Keyword(s):  
Sea Ice ◽  
Nitrogen Uptake ◽  
N Uptake ◽  
Total Carbon ◽  
The Arctic ◽  
Carbon And Nitrogen ◽  
Uptake Rates ◽  
Wide Range ◽  
Small Phytoplankton

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 μm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labelling experiments for the first time as part of the NABOS (Nansen and Amundsen Basins Observational System) program during August 21 to September 22, 2013. The depth integrated C, NO3−, and NH4+ uptake rates by small phytoplankton showed a wide range from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3−, and NH4+ was varied from 24 to 89 %, 32 to 89 %, and 28 to 89 %, respectively. The turnover times for NO3− and NH4+ by small phytoplankton during the present study point towards the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3−. Relatively, higher C and N uptake rates by small phytoplankton obtained during the present study at locations with less sea ice concentrations points towards the possibility of small phytoplankton thrive under sea ice retreat under warming conditions. The high contributions of small phytoplankton towards the total carbon and nitrogen uptake rates suggest capability of small size autotrophs to withstand in the adverse hydrographic conditions introduced by climate change.

scholarly journals Effects of pyrolysis parameters on the yield and properties of biochar from pelletized sunflower husk

2018 ◽  
Vol 44 ◽  
pp. 00197 ◽  
Author(s):  
Katarzyna Wystalska ◽  
Krystyna Malińska ◽  
Renata Włodarczyk ◽  
Olga Chajczyk
Keyword(s):  
Food Processing ◽  
Chemical Properties ◽  
Total Carbon ◽  
Physical And Chemical Properties ◽  
Wide Range ◽  
Agricultural Applications ◽  
Agriculture And Food ◽  
Pyrolysis Of Biomass ◽  
Physical And Chemical ◽  
And Chemical Properties

Pyrolysis of biomass residues from agriculture and food processing industry allows production of biochars with diverse physical and chemical properties for a wide range of applications in agriculture and environmental protection. Biochars produced from pelletized sunflower husks through slow pyrolysis in the range of temperatures (480–580°C) showed total carbon of 70.53%–81.96%, total nitrogen of 1.2%, alkaline pH (9.37–10.32), low surface area (0.93–2.91 m2 g-1) and porosity of 13.23–15.43%. Higher pyrolysis temperatures resulted in lower biochar yields. With the increase in temperature the content of organic matter, nitrogen, Ca and Mg decreased whereas the increase in temperature resulted in higher contents of total carbon and phosphorus. Produced biochars showed potential for agricultural applications.

Interferons in the treatment of human cancer.

1984 ◽  
Vol 2 (4) ◽  
pp. 336-352 ◽  
Author(s):  
J M Kirkwood ◽  
M S Ernstoff
Keyword(s):  
Recombinant Dna ◽  
Human Cancer ◽  
Clinical Results ◽  
Common Species ◽  
Current Phase ◽  
Recombinant Dna Technology ◽  
Disease States ◽  
Wide Range

The interferons are the best known of biologic antineoplastic agents. Progress with the clinical application of interferons to cancer has been slow and complicated by the need for attention to a new spectrum of therapeutic and toxic effects manifest by the interferons. This summary of current phase I and II trial results with the interferons establishes their clinical potential. The maximally tolerated dosages of the most common species of interferon alpha produced in eukaryotic cells as well as by recombinant DNA technology in bacteria are now described in a variety of different disease states. "Naturally" produced eukaryotic as well as bacterially synthesized interferons have a similar, wide range of biologic effects in vitro and in vivo. Antiviral, antiproliferative, immunologic, and enzymologic functions of the interferons relevant to antineoplastic functions are under study. Knowledge of these mechanisms should improve the clinical results obtained in human cancer. Species and subspecies differences in the activity of interferons may lead to selective use of the pure interferon subspecies, alone or in combination. The use of the interferons and other antineoplastic biologics, such as antibody or chemotherapy, are subsequent goals that are now on the horizon.

Discordance between measured and calculated total carbon dioxide

1990 ◽  
Vol 36 (12) ◽  
pp. 2093-2096 ◽  
Author(s):  
J P Ungerer ◽  
M J Ungerer ◽  
W J Vermaak
Keyword(s):  
Small Variation ◽  
Total Carbon ◽  
Excellent Correlation ◽  
Acid Base ◽  
Absolute Minimum ◽  
Sample Handling ◽  
Wide Range ◽  
Acid Base Status ◽  
Analytical Variation ◽  
Range Of Values

Abstract Recent studies on the agreement and correlation between measured and calculated total CO2 (TCO2) have yielded conflicting results. Pre-analytical variation could have been partially responsible. While keeping such variables at an absolute minimum, we found excellent correlation (r = 0.98) in 88 samples, with only a small variation in agreement between measured and calculated TCO2 values (SD = 1.1 mmol/L), which could be a function of variation in apparent pK (pK'). A subsequent evaluation of 913 consecutive samples, routinely analyzed, yielded similar results. These results suggest that some of the discrepancies reported in the literature could be ascribable to differences in sample types and sample handling. Rigid control of pre-analytical procedures is therefore a prerequisite in studies on this topic. The two methods were found to agree over a wide range of values, such that either of them could be used to evaluate clinical acid-base status accurately.

Crustacean Plankton Communities in Forty-Five Lakes in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 231-244 ◽  
Author(s):  
Kazimierz Patalas
Keyword(s):  
Common Species ◽  
Medium Size ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Lake Morphology ◽  
Diaptomus Oregonensis ◽  
Crustacean Plankton ◽  
Limnocalanus Macrurus ◽  
Zooplankton Communities ◽  
Plankton Communities

Zooplankton communities were characterized on the basis of samples taken in summer as vertical net hauls in the central part of lakes. Twenty-eight species of crustaceans were found in the 45 lakes studied. The highest number of species as well as the highest numbers of individuals (per unit of area) usually occurred in the largest deepest lakes with most transparent water.The most common species were: Bosmina longirostris, Tropocyclops prasinus mexicanus, Mesocyclops edax, Diaptomus minutus, Holopedium gibberum, and Cyclops bicuspidatus thomasi. Daphnids were rather scarcely represented.Senecella calanoides, Limnocalanus macrurus, and Diaptomus sicilis were confined to rather deeper lakes, whereas Diaptomus oregonensis was found mostly in smaller shallower lakes and Diaptomus leptopus in very small, but relatively deep lakes. Diaptomus minutus and C. b. thomasi, though widely distributed, showed a preference for deeper lakes, whereas T. p. mexicanus tended towards smaller shallower lakes.In particular lakes, the number of dominants ranged between 1 and 5, but three dominants per lake was the most commonly encountered case. The simplest community was composed of one cyclopoid, though the most common consisted of one cyclopoid, one diaptomid, and one cladoceran.Four types of communities were distinguished, each of them characteristic for a group of lakes of specific size and depth: (I) in the largest and deepest lakes (389–1007 ha of area, 30–117 m maximum depth); (II) in lakes of medium size and depth (6.5–200 ha, 4.8–33 m); (III) in small and very shallow lakes (3.1–28 ha, 2.7–7.3 m); (IV) in very small lakes with medium depth (1.3–3.7 ha, 6.1–12.8 m).The high degree of similarity between the plankton communities of the Experimental Lakes Area (ELA) and southern Ontario, as well as of some Great Lakes, suggest that they all basically belong to the same zoogeographical area.The fact that most species were distributed evenly throughout ELA may indicate the relative uniformity of the area. In ELA, lake morphology is mainly responsible for defining the type of community.

Protein Synthesis by Lake Plankton Measured Using in situ Carbon Dioxide and Sulfate Assimilation

1987 ◽  
Vol 44 (12) ◽  
pp. 2102-2117 ◽  
Author(s):  
Russell L. Cuhel ◽  
David R. S. Lean
Keyword(s):  
Carbon Dioxide ◽  
Protein Synthesis ◽  
Carbon Fixation ◽  
Total Carbon ◽  
Light Limitation ◽  
Sulfate Assimilation ◽  
Sulfate Uptake ◽  
Chl A ◽  
Total Sulfate

Sequential 4- to 6-h in situ measurements of carbon dioxide and sulfate uptake showed midday deepening of the depth of Pmax and photoinhibition of upper water column samples. Analysis of subcellular fractions accentuated total uptake measurements, with net protein synthesis providing a direct measure of growth. The percentage of carbon assimilated into protein was smallest at the depth of maximum photosynthesis and increased with light limitation. Summed incubations agreed well with all-day deployments for total carbon fixation and protein synthesis. Assimilation numbers were consistently low (<2.5 g C∙g Chl a−1∙h-1 with integrated (0–20 m) areal production of 616–1467 mg C∙m−2 and 7.5–32.4 mg S∙m−2 during the light day. Nonreductive sulfate assimilation (predominantly ester-SO4−) accounted for up to 40% of the total sulfate uptake when diatoms predominated. Protein synthesis measured with 35S (200–1000 mg protein∙m−2 during the light day) increased 57–89% overnight. Hourly rates were similar during light and scotophase incubations. Night metabolism substantially altered the biochemical composition (e.g. protein, lipid, and carbohydrate) of the plankton with respect to newly incorporated carbon. Combined plant-specific H14CO3− and general microbial 3SSO42− techniques suggested algal dominance in the mixed layer.

scholarly journals Glucose transport as rate-limiting step in the growth of Escherichia coli on glucose

1976 ◽  
Vol 156 (2) ◽  
pp. 477-480 ◽  
Author(s):  
D Herbert ◽  
H L Kornberg
Keyword(s):  
Escherichia Coli ◽  
Continuous Culture ◽  
Glucose Transport ◽  
Growth Rates ◽  
Glucose Limitation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Wide Range ◽  
Rate Limiting

Over a wide range of growth rates, two strains of Escherichia coli growing aerobically in continuous culture under glucose limitation utilized glucose at rates identical with those at which cells harvested from the chemostats transported [14C]glucose.

Volatile organic compounds in barite-hosted fluid inclusions from the 3.5 Ga old Dresser Formation, Western Australia

2020 ◽  
Author(s):  
Volker Thiel ◽  
Jan-Peter Duda ◽  
Alfons M. van den Kerkhof ◽  
Joachim Reitner ◽  
Helge Mißbach
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Western Australia ◽  
Fluid Inclusions ◽  
Carbon Fixation ◽  
Solid Phase ◽  
Inorganic Compounds ◽  
Wide Range ◽  
Volatile Organic ◽  
Artefact Formation

&lt;p&gt;The c. 3.5 Ga Dresser Formation of the East Pilbara Craton (Western Australia) contains large amounts of blackish barite. These rocks produce an intense sulfidic odor when crushed, resulting from abundant primary fluid inclusions. In part, the black barites are interbedded with sulfidic stromatolites. Using Raman spectroscopy, microthermometry, and two different online GC&amp;#8211;MS approaches, we characterized in detail the chemical composition of the barite-hosted fluid inclusions. Our GC&amp;#8211;MS techniques were based on (i) thermodecrepitation at 150-250&amp;#176;C and (ii) solid phase microextraction (SPME)&amp;#8211;GC&amp;#8211;MS at reduced temperature (50&amp;#176;C), thereby minimizing external contamination and artefact formation. Major fluid inclusion classes yielded mainly H&lt;sub&gt;2&lt;/sub&gt;O, CO&lt;sub&gt;2&lt;/sub&gt;, and H&lt;sub&gt;2&lt;/sub&gt;S in varying abundance, along with minor amounts of COS and &amp;#160;CS&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;, and CH&lt;sub&gt;4&lt;/sub&gt; (&lt; 1%). Notably, we also detected a wide range of volatile organic compounds, including short&amp;#8211;chain ketones and aldehydes, thiophenes, and various organic (poly)sulfides. Some of these compounds (CH&lt;sub&gt;3&lt;/sub&gt;SH, acetic acid) have previously been invoked as initials agents for carbon fixation under primordial conditions, but up to now their presence had not been observed in Precambrian materials. Based on our findings, we hypothesize that hydrothermal seepage of organic and inorganic compounds during Dresser times provided both, catabolic and anabolic substrates for early microbial metabolisms.&lt;/p&gt;

scholarly journals A 40-million-year history of atmospheric CO 2

2013 ◽  
Vol 371 (2001) ◽  
pp. 20130096 ◽  
Author(s):  
Yi Ge Zhang ◽  
Mark Pagani ◽  
Zhonghui Liu ◽  
Steven M. Bohaty ◽  
Robert DeConto
Keyword(s):  
Middle Miocene ◽  
Carbon Fixation ◽  
Middle Eocene ◽  
Ice Sheet ◽  
Algal Growth ◽  
Equatorial Atlantic ◽  
Antarctic Ice Sheet ◽  
The Past ◽  
Wide Range

The alkenone– p CO 2 methodology has been used to reconstruct the partial pressure of ancient atmospheric carbon dioxide ( p CO 2 ) for the past 45 million years of Earth's history (Middle Eocene to Pleistocene epochs). The present long-term CO 2 record is a composite of data from multiple ocean localities that express a wide range of oceanographic and algal growth conditions that potentially bias CO 2 results. In this study, we present a p CO 2 record spanning the past 40 million years from a single marine locality, Ocean Drilling Program Site 925 located in the western equatorial Atlantic Ocean. The trends and absolute values of our new CO 2 record site are broadly consistent with previously published multi-site alkenone–CO 2 results. However, new p CO 2 estimates for the Middle Miocene are notably higher than published records, with average p CO 2 concentrations in the range of 400–500 ppm. Our results are generally consistent with recent p CO 2 estimates based on boron isotope-pH data and stomatal index records, and suggest that CO 2 levels were highest during a period of global warmth associated with the Middle Miocene Climatic Optimum (17–14 million years ago, Ma), followed by a decline in CO 2 during the Middle Miocene Climate Transition (approx. 14 Ma). Several relationships remain contrary to expectations. For example, benthic foraminiferal δ 18 O records suggest a period of deglaciation and/or high-latitude warming during the latest Oligocene (27–23 Ma) that, based on our results, occurred concurrently with a long-term decrease in CO 2 levels. Additionally, a large positive δ 18 O excursion near the Oligocene–Miocene boundary (the Mi-1 event, approx. 23 Ma), assumed to represent a period of glacial advance and retreat on Antarctica, is difficult to explain by our CO 2 record alone given what is known of Antarctic ice sheet history and the strong hysteresis of the East Antarctic Ice Sheet once it has grown to continental dimensions. We also demonstrate that in the Neogene with low CO 2 levels, algal carbon concentrating mechanisms and spontaneous biocarbonate–CO 2 conversions are likely to play a more important role in algal carbon fixation, which provides a potential bias to the alkenone– p CO 2 method.

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