Effects of nitrogen limitation on uptake of inorganic carbon and specific activity of ribulose-1,5-bisphosphate carboxylase/oxygenase in green microalgae

1991 ◽  
Vol 69 (5) ◽  
pp. 1146-1150 ◽  
Author(s):  
John Beardall ◽  
Simon Roberts ◽  
Jenny Millhouse
Keyword(s):  
Growth Rate ◽  
Key Words ◽  
Growth Rates ◽  
Nitrogen Limitation ◽  
Inorganic Carbon ◽  
Marked Decrease ◽  
Specific Activity ◽  
Green Microalgae ◽  
Bisphosphate Carboxylase ◽  
Cell Basis

The effects of nitrogen limitation on the characteristics of inorganic carbon-dependent O2 evolution have been examined in the green microalgae Chlorella emersonii and Gloeomonas sp. When cells were grown under 5% CO2 or air, decreasing the growth rate (increasing nitrogen limitation) caused a decrease in maximum rates of photosynthetic O2 evolution, although when expressed on a per cell basis such changes were only evident at growth rates below 0.16 day−1. Severe nitrogen limitation also caused a marked decrease in k1/2 (CO2) in light- and CO2-dependent O2 evolution. Although values for this parameter were not as low as for low CO2 grown cells with a fully induced CO2-concentrating mechanism, they were less than one-half the corresponding values from cells with the mechanism fully repressed. Nitrogen-limitation also resulted in decreases in the activity and cellular content of ribulose-1,5-bisphosphate carboxylase/oxygenase. The changes to activity and levels of this enzyme were not equivalent so the specific activity decreased dramatically between growth rates of 0.57 and 0.25 day−1. Similar effects were noted in Gloeomonas and in air-grown Chlorella. The results are discussed in relation to regulation of CO2 uptake and assimilation in microalgae. Key words: microalgae, CO2 assimilation, nitrogen limitation, Rubisco, Chlorella.

Growth rate and antibiotic sensitivities of conidium and selfed-oospore progenies of heterothallic Pythium splendens

1994 ◽  
Vol 72 (11) ◽  
pp. 1709-1712 ◽  
Author(s):  
L. Y. Guo ◽  
W. H. Ko
Keyword(s):  
Growth Rate ◽  
Key Words ◽  
Growth Rates ◽  
Antibiotic Sensitivity ◽  
Rate Sensitivity ◽  
Phenotypic Characteristic ◽  
Polygenic Inheritance ◽  
Pythium Splendens

Isolate 167F of Pythium splendens and its four selfed-oospore isolates gave rise to conidium progeny similar to their respective parents in growth rate. However, oospore progeny from these isolates displayed considerable variation in this phenotypic characteristic. These isolates also showed similarity in conidium progeny and dissimilarity in selfed-oospore progeny in sensitivity to streptomycin and chloramphenicol. Among the 117 oospore cultures obtained from isolate 167F, resistance to streptomycin and chloramphenicol was negatively correlated with the growth rates. Results from this study suggest the polygenic inheritance with alternate alleles at each locus for growth rate, sensitivity to streptomycin, and sensitivity to chloramphenicol. Key words: Pythium splendens, conidium progeny, oospore progeny, growth rate, antibiotic sensitivity.

scholarly journals Regulation of the Cellulosomal celS (cel48A) Gene of Clostridium thermocellum Is Growth Rate Dependent

2003 ◽  
Vol 185 (10) ◽  
pp. 3042-3048 ◽  
Author(s):  
Tali W. Dror ◽  
Ely Morag ◽  
Adi Rolider ◽  
Edward A. Bayer ◽  
Raphael Lamed ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Clostridium Thermocellum ◽  
Nitrogen Limitation ◽  
Rnase Protection Assay ◽  
Crystalline Cellulose ◽  
Carbon Limitation ◽  
Transcriptional Level ◽  
Continuous Cultures ◽  
Rnase Protection

ABSTRACT Clostridium thermocellum produces an extracellular multienzyme complex, termed cellulosome, that allows efficient solubilization of crystalline cellulose. One of the major enzymes in this complex is the CelS (Cel48A) exoglucanase. The regulation of CelS at the protein and transcriptional levels was studied using batch and continuous cultures. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses indicated that the amount of CelS in the supernatant fluids of cellobiose-grown cultures is lower than that of cellulose-grown cultures. The transcriptional level of celS mRNA was determined quantitatively by RNase protection assays with batch and continuous cultures under carbon and nitrogen limitation. The amount of celS mRNA transcripts per cell was about 180 for cells grown under carbon limitation at growth rates of 0.04 to 0.21 h−1 and 80 and 30 transcripts per cell for batch cultures at growth rates of 0.23 and 0.35 h−1, respectively. Under nitrogen limitation, the corresponding levels were 110, 40, and 30 transcripts/cell for growth rates of 0.07, 0.11, and 0.14 h−1, respectively. Two major transcriptional start sites were detected at positions −140 and −145 bp, upstream of the translational start site of the celS gene. The potential promoters exhibited homology to known sigma factors (i.e., σA and σB) of Bacillus subtilis. The relative activity of the two promoters remained constant under the conditions studied and was in agreement with the results of the RNase protection assay, in which the observed transcriptional activity was inversely proportional to the growth rate.

scholarly journals Signals of aging associated with lower growth rates in Kluyveromyces lactis cultures under nitrogen limitation

2014 ◽  
Vol 60 (9) ◽  
pp. 605-612
Author(s):  
Lygia Fátima da Mata Corrêa ◽  
Frederico José Vieira Passos ◽  
Marlene Isabel Vargas Viloria ◽  
Olindo Assis Martins Filho ◽  
Andréa Teixeira de Carvalho ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Rates ◽  
Nitrogen Limitation ◽  
Specific Growth ◽  
Kluyveromyces Lactis ◽  
Continuous Cultures ◽  
Lower Growth ◽  
Nitrogen Concentrations ◽  
Apoptosis Markers

The effects of aging on the specific growth rate of Kluyveromyces lactis cultures, as a function of (NH4)2SO4 concentration, were evaluated. The growth kinetic parameters maximum specific growth rate and saturation constant for (NH4)2SO4 were calculated to be 0.44 h−1 and 0.15 mmol·L−1, respectively. Batch cultures were allowed to age for 16 days without influence of cell density or starvation. The specific growth rates of these cultures were determined each day and decreased as the population aged at different nitrogen concentrations. Aging signals (N-acetylglucosamine content of the cell wall, cell dimensions, and apoptosis markers) were measured. Apoptosis markers were detected after 5 days at limiting (NH4)2SO4 concentrations (0.57, 3.80, and 7.60 mmol·L−1) but only after 8 days at a nonlimiting (NH4)2SO4 concentration (38.0 mmol·L−1). Similarly, continuous cultures of K. lactis performed under nitrogen limitation and, at lower dilution rates, accumulated cells exhibiting aging signals. The results demonstrate that aging affects growth rate and raise the question of whether nitrogen limitation accelerates aging. Because aging is correlated with growth rate, and each dilution rate of the continuous cultures tends to select and accumulate cells with a respective age, cultures growing at lower growth rates can be useful to investigate yeast physiological responses, including aging.

scholarly journals High ribulose-1,5-bisphosphate carboxylase/oxygenase content in northern diatom species

2019 ◽  
Author(s):  
A. C. Gerecht ◽  
G. K. Eriksen ◽  
M. Uradnikova ◽  
H. C. Eilertsen
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Growth Rates ◽  
Total Protein ◽  
High Growth ◽  
Cellular Protein ◽  
Diatom Species ◽  
Bisphosphate Carboxylase ◽  
Total Cellular Protein

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is a fundamental enzyme in CO2-fixation in photoautotrophic organisms. Nonetheless, it has been recently suggested that the contribution of this enzyme to total cellular protein is low in phytoplankton, including diatoms (< 6%). Here we show that RuBisCO content is high in some diatom species isolated from northern waters (> 69°N). Two species contained the highest RuBisCO levels ever reported for phytoplankton (36% of total protein). These high RuBisCO requirements do not increase these species’ requirements for nitrogen and do not impart a fitness disadvantage in terms of growth rate. On the contrary, high RuBisCO levels in psychrophilic diatoms may be a necessary mechanism to maintain high growth rates at low temperature at which enzymatic rates are low.

Comparison of copper sulphate pentahydrate growth rates determined by different methods

1990 ◽  
Vol 55 (7) ◽  
pp. 1691-1707 ◽  
Author(s):  
Miloslav Karel ◽  
Jiří Hostomský ◽  
Jaroslav Nývlt ◽  
Axel König
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Fluidized Bed ◽  
Growth Rates ◽  
Copper Sulphate ◽  
Crystal Growth Rate ◽  
Effect Of Temperature ◽  
Rotating Disc ◽  
Shape Factors ◽  
Data Treatment

Crystal growth rates of copper sulphate pentahydrate (CuSO4.5 H2O) determined by different authors and methods are compared. The methods included in this comparison are: (i) Measurement on a fixed crystal suspended in a streaming solution, (ii) measurement on a rotating disc, (iii) measurement in a fluidized bed, (iv) measurement in an agitated suspension. The comparison involves critical estimation of the supersaturation used in measurements, of shape factors used for data treatment and a correction for the effect of temperature. Conclusions are drawn for the choice of values to be specified when data of crystal growth rate measurements are published.

Measurement of growth rates for single crystals and pressed tablets of CuSO4.5 H2O on a rotating disc

1989 ◽  
Vol 54 (11) ◽  
pp. 2951-2961 ◽  
Author(s):  
Miloslav Karel ◽  
Jaroslav Nývlt
Keyword(s):  
Growth Rate ◽  
Single Crystal ◽  
Single Crystals ◽  
Growth Rates ◽  
Diffusion Coefficients ◽  
Preferred Orientation ◽  
Rotating Disc ◽  
Dissolution Rates ◽  
Rates Of Growth ◽  
Good Agreement

Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.

scholarly journals Accuracy of State-Level Surveillance during Emerging Outbreaks of Respiratory Viruses: A Model-Based Assessment

2021 ◽  
pp. 0272989X2110222
Author(s):  
Yuwen Gu ◽  
Elise DeDoncker ◽  
Richard VanEnk ◽  
Rajib Paul ◽  
Susan Peters ◽  
...  
Keyword(s):  
Growth Rate ◽  
Data Collection ◽  
Disease Progression ◽  
Health Care Providers ◽  
Growth Rates ◽  
State Level ◽  
Future Research ◽  
Care Providers ◽  
State Surveillance ◽  
First Come First Serve

It is long perceived that the more data collection, the more knowledge emerges about the real disease progression. During emergencies like the H1N1 and the severe acute respiratory syndrome coronavirus 2 pandemics, public health surveillance requested increased testing to address the exacerbated demand. However, it is currently unknown how accurately surveillance portrays disease progression through incidence and confirmed case trends. State surveillance, unlike commercial testing, can process specimens based on the upcoming demand (e.g., with testing restrictions). Hence, proper assessment of accuracy may lead to improvements for a robust infrastructure. Using the H1N1 pandemic experience, we developed a simulation that models the true unobserved influenza incidence trend in the State of Michigan, as well as trends observed at different data collection points of the surveillance system. We calculated the growth rate, or speed at which each trend increases during the pandemic growth phase, and we performed statistical experiments to assess the biases (or differences) between growth rates of unobserved and observed trends. We highlight the following results: 1) emergency-driven high-risk perception increases reporting, which leads to reduction of biases in the growth rates; 2) the best predicted growth rates are those estimated from the trend of specimens submitted to the surveillance point that receives reports from a variety of health care providers; and 3) under several criteria to queue specimens for viral subtyping with limited capacity, the best-performing criterion was to queue first-come, first-serve restricted to specimens with higher hospitalization risk. Under this criterion, the lab released capacity to subtype specimens for each day in the trend, which reduced the growth rate bias the most compared to other queuing criteria. Future research should investigate additional restrictions to the queue.

scholarly journals StalGrowth—A Program to Estimate Speleothem Growth Rates and Seasonal Growth Variations

Geosciences ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 187
Author(s):  
Rolf Vieten ◽  
Francisco Hernandez
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Environmental Parameters ◽  
Ion Concentration ◽  
Radiometric Dating ◽  
Seasonal Growth ◽  
Climate Signal ◽  
Show Evidence ◽  
Cave Monitoring ◽  
Calcium Ion Concentration

Speleothems are one of the few archives which allow us to reconstruct the terrestrial paleoclimate and help us to understand the important climate dynamics in inhabited regions of our planet. Their time of growth can be precisely dated by radiometric techniques, but unfortunately seasonal radiometric dating resolution is so far not feasible. Numerous cave environmental monitoring studies show evidence for significant seasonal variations in parameters influencing carbonate deposition (calcium-ion concentration, cave air pCO2, drip rate and temperature). Variations in speleothem deposition rates need to be known in order to correctly decipher the climate signal stored in the speleothem archive. StalGrowth is the first software to quantify growth rates based on cave monitoring results, detect growth seasonality and estimate the seasonal growth bias. It quickly plots the predicted speleothem growth rate together with the influencing cave environmental parameters to identify which parameter(s) cause changes in speleothem growth rate, and it can also identify periods of no growth. This new program has been applied to multiannual cave monitoring studies in Austria, Gibraltar, Puerto Rico and Texas, and it has identified two cases of seasonal varying speleothem growth.

scholarly journals Effect of Light Intensity and Quality on Growth Rate and Composition of Chlorella vulgaris

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Maria N. Metsoviti ◽  
George Papapolymerou ◽  
Ioannis T. Karapanagiotidis ◽  
Nikolaos Katsoulas
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Chlorella Vulgaris ◽  
Lipid Content ◽  
Growth Rates ◽  
Solar Irradiance ◽  
White Led ◽  
Microalgal Biomass ◽  
Nm Range ◽  
Effect Of Light

In this research, the effect of solar irradiance on Chlorella vulgaris cultivated in open bioreactors under greenhouse conditions was investigated, as well as of ratio of light intensity in the 420–520 nm range to light in the 580–680 nm range (I420–520/I580–680) and of artificial irradiation provided by red and white LED lamps in a closed flat plate laboratory bioreactor on the growth rate and composition. The increase in solar irradiance led to faster growth rates (μexp) of C. vulgaris under both environmental conditions studied in the greenhouse (in June up to 0.33 d−1 and in September up to 0.29 d−1) and higher lipid content in microalgal biomass (in June up to 25.6% and in September up to 24.7%). In the experiments conducted in the closed bioreactor, as the ratio I420–520/I580–680 increased, the specific growth rate and the biomass, protein and lipid productivities increased as well. Additionally, the increase in light intensity with red and white LED lamps resulted in faster growth rates (the μexp increased up to 0.36 d−1) and higher lipid content (up to 22.2%), while the protein, fiber, ash and moisture content remained relatively constant. Overall, the trend in biomass, lipid, and protein productivities as a function of light intensity was similar in the two systems (greenhouse and bioreactor).

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