scholarly journals Isolation, growth, and nitrogen fixation rates of the Hemiaulus-Richelia (diatom-cyanobacterium) symbiosis in culture

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10115
Author(s):  
Amy E. Pyle ◽  
Allison M. Johnson ◽  
Tracy A. Villareal
Keyword(s):  
Nitrogen Fixation ◽  
Growth Rates ◽  
Maximum Growth ◽  
Light Level ◽  
Light Saturation ◽  
Nitrogen Fixers ◽  
Successful Isolation ◽  
Saturation Kinetics ◽  
Marine Symbiosis ◽  
Multiple Strains

Nitrogen fixers (diazotrophs) are often an important nitrogen source to phytoplankton nutrient budgets in N-limited marine environments. Diazotrophic symbioses between cyanobacteria and diatoms can dominate nitrogen-fixation regionally, particularly in major river plumes and in open ocean mesoscale blooms. This study reports the successful isolation and growth in monocultures of multiple strains of a diatom-cyanobacteria symbiosis from the Gulf of Mexico using a modified artificial seawater medium. We document the influence of light and nutrients on nitrogen fixation and growth rates of the host diatom Hemiaulus hauckii Grunow together with its diazotrophic endosymbiont Richelia intracellularis Schmidt, as well as less complete results on the Hemiaulus membranaceus-R. intracellularis symbiosis. The symbioses rates reported here are for the joint diatom-cyanobacteria unit. Symbiont diazotrophy was sufficient to support both the host diatom and cyanobacteria symbionts, and the entire symbiosis replicated and grew without added nitrogen. Maximum growth rates of multiple strains of H. hauckii symbioses in N-free medium with N2 as the sole N source were 0.74–0.93 div d−1. Growth rates followed light saturation kinetics in H. hauckii symbioses with a growth compensation light intensity (EC) of 7–16 µmol m−2s−1and saturation light level (EK) of 84–110 µmol m−2s−1. Nitrogen fixation rates by the symbiont while within the host followed a diel pattern where rates increased from near-zero in the scotophase to a maximum 4–6 h into the photophase. At the onset of the scotophase, nitrogen-fixation rates declined over several hours to near-zero values. Nitrogen fixation also exhibited light saturation kinetics. Maximum N2 fixation rates (84 fmol N2 heterocyst−1h−1) in low light adapted cultures (50 µmol m−2s−1) were approximately 40–50% of rates (144–154 fmol N2 heterocyst−1h−1) in high light (150 and 200 µmol m−2s−1) adapted cultures. Maximum laboratory N2 fixation rates were ~6 to 8-fold higher than literature-derived field rates of the H. hauckii symbiosis. In contrast to published results on the Rhizosolenia-Richelia symbiosis, the H. hauckii symbiosis did not use nitrate when added, although ammonium was consumed by the H. hauckii symbiosis. Symbiont-free host cell cultures could not be established; however, a symbiont-free H. hauckii strain was isolated directly from the field and grown on a nitrate-based medium that would not support DDA growth. Our observations together with literature reports raise the possibility that the asymbiotic H. hauckii are lines distinct from an obligately symbiotic H. hauckii line. While brief descriptions of successful culture isolation have been published, this report provides the first detailed description of the approaches, handling, and methodologies used for successful culture of this marine symbiosis. These techniques should permit a more widespread laboratory availability of these important marine symbioses.

Reassessment of Maximum Growth Rates for C3 and C4 Crops

1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growing Season ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Crop Growth ◽  
Close Inspection ◽  
Similar Difference ◽  
Photosynthetic Efficiencies

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.

Single Crystal Silicon Carbide On Silicon Using A Supersonic Gas Jet Of Methylsilane

1997 ◽  
Vol 483 ◽  
Author(s):  
S. A. Ustin ◽  
C. Long ◽  
L. Lauhon ◽  
W. Ho
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Single Crystal Silicon ◽  
Maximum Growth ◽  
X Ray Diffraction ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Supersonic Molecular Beam ◽  
Transmission Electron

AbstractCubic SiC films have been grown on Si(001) and Si(111) substrates at temperatures between 600 °C and 900 °C with a single supersonic molecular beam source. Methylsilane (H3SiCH3) was used as the sole precursor with hydrogen and nitrogen as seeding gases. Optical reflectance was used to monitor in situ growth rate and macroscopic roughness. The growth rate of SiC was found to depend strongly on substrate orientation, methylsilane kinetic energy, and growth temperature. Growth rates were 1.5 to 2 times greater on Si(111) than on Si(001). The maximum growth rates achieved were 0.63 μm/hr on Si(111) and 0.375μm/hr on Si(001). Transmission electron diffraction (TED) and x-ray diffraction (XRD) were used for structural characterization. In-plane azimuthal (ø-) scans show that films on Si(001) have the correct 4-fold symmetry and that films on Si(111) have a 6-fold symmetry. The 6-fold symmetry indicates that stacking has occurred in two different sequences and double positioning boundaries have been formed. The minimum rocking curve width for SiC on Si(001) and Si(111) is 1.2°. Fourier Transform Infrared (FTIR) absorption was performed to discern the chemical bonding. Cross Sectional Transmission Electron Microscopy (XTEM) was used to image the SiC/Si interface.

Dynamic Predictive Model for Growth of Bacillus cereus from Spores in Cooked Beans

2017 ◽  
Vol 81 (2) ◽  
pp. 308-315 ◽  
Author(s):  
Vijay K. Juneja ◽  
Abhinav Mishra ◽  
Abani K. Pradhan
Keyword(s):  
Bacillus Cereus ◽  
Growth Rates ◽  
Linear Models ◽  
Growth Models ◽  
Maximum Growth ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Growth Data ◽  
Three Phase ◽  
Primary Model

ABSTRACT Kinetic growth data for Bacillus cereus grown from spores were collected in cooked beans under several isothermal conditions (10 to 49°C). Samples were inoculated with approximately 2 log CFU/g heat-shocked (80°C for 10 min) spores and stored at isothermal temperatures. B. cereus populations were determined at appropriate intervals by plating on mannitol–egg yolk–polymyxin agar and incubating at 30°C for 24 h. Data were fitted into Baranyi, Huang, modified Gompertz, and three-phase linear primary growth models. All four models were fitted to the experimental growth data collected at 13 to 46°C. Performances of these models were evaluated based on accuracy and bias factors, the coefficient of determination (R2), and the root mean square error. Based on these criteria, the Baranyi model best described the growth data, followed by the Huang, modified Gompertz, and three-phase linear models. The maximum growth rates of each primary model were fitted as a function of temperature using the modified Ratkowsky model. The high R2 values (0.95 to 0.98) indicate that the modified Ratkowsky model can be used to describe the effect of temperature on the growth rates for all four primary models. The acceptable prediction zone (APZ) approach also was used for validation of the model with observed data collected during single and two-step dynamic cooling temperature protocols. When the predictions using the Baranyi model were compared with the observed data using the APZ analysis, all 24 observations for the exponential single rate cooling were within the APZ, which was set between −0.5 and 1 log CFU/g; 26 of 28 predictions for the two-step cooling profiles also were within the APZ limits. The developed dynamic model can be used to predict potential B. cereus growth from spores in beans under various temperature conditions or during extended chilling of cooked beans.

Dynamic energy analysis to assess maximum growth rates in developing power generation capacity: case study of India

Energy Policy ◽  
2004 ◽  
Vol 32 (2) ◽  
pp. 281-287 ◽  
Author(s):  
Jyotirmay Mathur ◽  
Narendra Kumar Bansal ◽  
Hermann-Joseph Wagner
Keyword(s):  
Power Generation ◽  
Growth Rates ◽  
Energy Analysis ◽  
Maximum Growth ◽  
Generation Capacity

scholarly journals Interactions Between the Kleptoplastidic Dinoflagellate Shimiella gracilenta and Several Common Heterotrophic Protists

2021 ◽  
Vol 8 ◽  
Author(s):  
Sang Ah Park ◽  
Hae Jin Jeong ◽  
Jin Hee Ok ◽  
Hee Chang Kang ◽  
Ji Hyun You ◽  
...  
Keyword(s):  
Growth Rates ◽  
Ingestion Rate ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Prey Concentration ◽  
Ingestion Rates ◽  
Oxyrrhis Marina ◽  
Planktonic Food ◽  
Moderate Growth ◽  
Algal Prey

The newly described dinoflagellate, Shimiella gracilenta, is known to survive for approximately 1 month on the plastids of ingested prey cells during starvation, indicating kleptoplastidy. To understand the population dynamics of this dinoflagellate in marine planktonic food webs, its growth and mortality rate due to predation should be assessed. Thus, we investigated the feeding occurrence of eight common heterotrophic protists on S. gracilenta. We also determined the growth and ingestion rates of Oxyrrhis marina and the naked ciliate, Rimostrombidium sp. on S. gracilenta as a function of the prey concentration. The common heterotrophic dinoflagellates (HTDs) Gyrodinium dominans, O. marina, and Pfiesteria piscicida and a naked ciliate Rimostrombidium sp. were able to feed on S. gracilenta; whereas the HTDs Aduncodinium glandula, Gyrodinium jinhaense, Oblea rotunda, and Polykrikos kofoidii were not. Shimiella gracilenta supported positive growth of O. marina and Rimostrombidium sp. but did not support that of G. dominans and P. piscicida. With increasing prey concentrations, the growth and ingestion rates of O. marina and Rimostrombidium sp. on S. gracilenta increased and became saturated. The maximum growth rates of O. marina and Rimostrombidium sp. on S. gracilenta were 0.645 and 0.903 day−1, respectively. Furthermore, the maximum ingestion rates of O. marina and Rimostrombidium sp. on S. gracilenta were 0.11 ng C predator day−1 (1.6 cells predator−1 day−1) and 35 ng C predator day−1 (500 cells predator−1 day−1), respectively. The maximum ingestion rate of O. marina on S. gracilenta was lower than that on any other algal prey reported to date, although its maximum growth rate was moderate. In conclusion, S. gracilenta had only a few common heterotrophic protist predators but could support moderate growth rates of the predators. Thus, S. gracilenta may not be a common prey species for diverse heterotrophic protists but may be a suitable prey for a few heterotrophic protists.

Clostridium tyrobutyricum Strains Show Wide Variation in Growth at Different NaCl, pH, and Temperature Conditions

2012 ◽  
Vol 75 (10) ◽  
pp. 1791-1795 ◽  
Author(s):  
MARJO RUUSUNEN ◽  
ANU SURAKKA ◽  
HANNU KORKEALA ◽  
MIIA LINDSTRÖM
Keyword(s):  
Growth Rates ◽  
Maximum Growth ◽  
Control Measures ◽  
Clostridium Tyrobutyricum ◽  
Food Control ◽  
Acid Fermentation ◽  
Temperature Conditions ◽  
Physiological Diversity ◽  
Nacl Concentration ◽  
Different Strains

Outgrowth from Clostridium tyrobutyricum spores in milk can lead to butyric acid fermentation in cheeses, causing spoilage and economical loss to the dairy industry. The aim of this study was to investigate the growth of 10 C. tyrobutyricum strains at different NaCl, pH, and temperature conditions. Up to 7.5-fold differences among the maximum growth rates of different strains in the presence of 2.0% NaCl were observed. Five of 10 strains were able to grow in the presence of 3.0% NaCl, while a NaCl concentration of 3.5% was completely inhibitory to all strains. Seven of 10 strains were able to grow at pH 5.0, and up to 4- and 12.5-fold differences were observed among the maximum growth rates of different strains at pH 5.5 and 7.5, respectively. The maximum growth temperatures varied from 40.2 to 43.3°C. The temperature of 10°C inhibited the growth of all strains, while 8 of 10 strains grew at 12 and 15°C. Despite showing no growth, all strains were able to survive at 10°C. In conclusion, wide variation was observed among different C. tyrobutyricum strains in their ability to grow at different stressful conditions. Understanding the physiological diversity among the strains is important when designing food control measures and predictive models for the growth of spoilage organisms in cheese.

Group I Clostridium botulinum Strains Show Significant Variation in Growth at Low and High Temperatures

2009 ◽  
Vol 72 (2) ◽  
pp. 375-383 ◽  
Author(s):  
KATJA HINDERINK ◽  
MIIA LINDSTRÖM ◽  
HANNU KORKEALA
Keyword(s):  
Growth Rates ◽  
Significant Variation ◽  
Clostridium Botulinum ◽  
Maximum Growth ◽  
Type B ◽  
Strain Variation ◽  
Optimum Growth Temperature ◽  
Group I ◽  
Botulinum Type ◽  
The Difference

The minimum and maximum growth temperatures of 23 group I Clostridium botulinum strains of the toxin types A, AB, B, and F were determined. Moreover, the maximum growth rates at 20, 37, and 42°C of the same strains were recorded. The minimum growth temperatures varied from 12.8 to 16.5°C, whereas the maximum growth temperatures showed even wider variation, from 40.9 to 48.0°C. At 20 and 37°C, a twofold difference in maximum growth rates between the slowest and the fastest growing strains was found; at 42°C the difference was more than 30-fold. As expected, all strains grew significantly slower at 20°C than at 37°C. However, eight type B strains grew substantially faster at 42°C than they did at 37°C. These findings indicate that the optimum growth temperature for some group I C. botulinum type B strains is higher than the temperature of 37°C that is generally accepted. A significant correlation between maximum growth rates at 42°C and maximum growth temperatures was found for type B and F strains, whereas for type A strains no such correlation could be found. Strain variation was particularly high for the type B strains, reflecting the wide genetic diversity of this toxin type. The significant variation between strains of group I C. botulinum may have an impact on inoculation studies and predictive modeling when assessing the safety of foods.

Influence of Sediment Disturbance and Water Flow on the Growth of the Soft-Shell Clam,Mya arenariaL.

1990 ◽  
Vol 47 (9) ◽  
pp. 1655-1663 ◽  
Author(s):  
Craig W. Emerson
Keyword(s):  
Water Flow ◽  
Growth Rates ◽  
Free Stream ◽  
Maximum Growth ◽  
Coastal Development ◽  
Low Flow ◽  
Stream Velocity ◽  
Soft Shell Clam ◽  
Sediment Disturbance ◽  
Soft Shell

The importance of sediment disturbance and water flow to the production of the soft-shell clam, Mya arenaria, was assessed in laboratory flumes by measuring growth rates of clams exposed to a gradation of bed shear stress, free-stream velocity, and frequency and depth of sediment disturbance over a 10-m period. In the absence of sediment disturbance, growth of soft-tissue was directly proportional to both free-stream (U) and shear (U*) velocity (r2 = 0.64 and 0.72, respectively). It was suggested that increased organic seston flux linked higher water flow to higher growth. In all treatments, maximum growth rates were observed with daily disturbance of the top centimeter of sediment. No level of disturbance resulted in growth rates lower than those of undisturbed clams in low flow (U = 0.4 cm∙s−1, U* = 0.1 cm∙s−1). The stimulation of growth under maximum sediment disturbance was removed when U exceeded ~3 cm∙s−1(U* = 0.7 cm∙s−1). An energy budget for M. arenaria indicated that the amount of organic material suspended during sediment disturbance was insufficient to account for the increased growth in clams subjected to high levels of disturbance. It was suggested that the sediment disturbance associated with intense clam harvesting, and changes in local hydrography resulting from coastal development, may be responsible for some of the unexplained growth variation in commercial clam stocks.

Kinetics And Morphology Of Homoepitaxial Cvd Growth On Diamond (100) And (111)

1995 ◽  
Vol 416 ◽  
Author(s):  
R. E. Rawles ◽  
W. G. Morris ◽  
M. P. D’Evelyn
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Chemical Vapor ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Arrhenius Behavior ◽  
Oriented Growth ◽  
Relative Growth Rates ◽  
Cvd Growth ◽  
Hot Filament

ABSTRACTGrowth rates for homoepitaxy of diamond (100) and (111) by hot-filament chemical vapor deposition were measured via in situ Fizeau interferometry and the surface morphologies were subsequently characterized by atomic force microscopy (AFM). (100)-oriented growth from 0.5% CH4 in H2 exhibited pure Arrhenius behavior, with an activation energy of 17±1 kcal/mol, up to a substrate temperature of 1100°C. Addition of oxygen to the feed gas resulted in an increased growth rate below 900°C, a maximum growth rate between 900 and 1000°C, and etching (of diamond) above 1050 - 1100°C. However, the presence of oxygen apparently had less effect on the surface morphology than did the (100)-to-(111) growth rate parameter α, determined directly from the relative growth rates of (100) and (111) substrates mounted side by side. During homoepitaxial growth from 0.5% CH4 in H2 at 875°C of ca. 1-micron-thick films,α = was 2.2 without oxygen and 1.3 for growth with 0.14% O2. The (100) film grown with α = 2.2 was quite smooth, while that with α = 1.3 was covered by numerous hillocks and penetration twins. AFM analysis revealed surprisingly little difference between the (111) films despite the considerable difference in α. Implications of these results for the growth mechanism are discussed.

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