ADAPTATION OF RUMEN BACTERIA TO SODIUM AND MONENSIN

1984 ◽  
Vol 64 (5) ◽  
pp. 351-353 ◽  
Author(s):  
R. I. MACKIE ◽  
P. G. BAHRS ◽  
J. J. THERION
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Key Words ◽  
Chemostat Culture ◽  
Rumen Bacteria ◽  
Ruminococcus Albus ◽  
Selenomonas Ruminantium

Rumen bacteria were able to adapt to concentrations of Na+ > 300 mM. This is higher than that normally found in the rumen (< 200 mM Na+). In chemostat culture both Selenomonas ruminantium and Ruminococcus albus adapted to the effects of Na+ and monensin. Substrate yields slowly decreased before reaching steady state values. Key words: Monensin, Na+, growth rate, substrate yield, rumen bacteria, adaptation

Sebatian Metoksiaromatik Sebagai Substrat Pertumbuhan dan Pengaruh Enzim Demetilase dalam Acetobacterium Woodii DSM 1030

2012 ◽  
Author(s):  
Mohd. Sahaid Hj. Kalil ◽  
Muhammad Zaki ◽  
Wan Mohtar Wan Yusoff ◽  
Mohammad Ramlan Mohd. Salleh
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Sole Carbon Source ◽  
Specific Growth ◽  
Chemostat Culture ◽  
Carbon Sources ◽  
Syringic Acid ◽  
Organic Substrate ◽  
Acetobacterium Woodii ◽  
Vanilic Acid

Penyelidikan ini bertujuan untuk menyaring substrat organik bagi untuk penghasilan sel–sel A. woodii teraruh demetilase. Pertumbuhan A. woodii dilakukan dalam medium “Balch” yang mengandungi sumber karbon berbeza dalam keadaan anaerobik. Sebanyak sebelas substrat telah diuji iaitu anisol, 2– dan 3–metoksifenol, asid vanilik, asid siringik, asid 2,3,4–, 2,4,5– dan 3,4,5–trimetoksi benzoik, 2,3,4–, 2,4,5– dan 3,4,5–trimetoksi benzil alkohol. 2–metoksifenol merupakan substrat terbaik untuk pertumbuhan A. woodii pada kadar pertumbuhan spesifik 0.14 j–1. Penghasilan sel–sel teraruh demetilase dilakukan dalam kultur kemostat pada kadar pencairan (D) 0.0j–1. Sel-sel pada keadaan mantap dituai dalam keadaan anaerobik dan dipekatkan sebelum digunakan. Pertumbuhan A. woodii didapati maksimum dengan menggunakan kepekatan 0.62 g/L 2–metoksifenol sebagai sumber karbon tunggal. Tindak balas penyahmetilan oleh sel–sel A. woodii meningkat sebanyak 78% apabila 2–metoksifenol sebanyak 0.31 g/L ditambah dalam medium yang mengandungi fruktosa (1% w/v) semasa kultur kemostat. Kata kunci: tindak balas penyahmetilan; demetilase; sel-sel tertuai; metosiaromatik, Acetobacteriumwoodii The objective of this project was to screen organic substrate suitable for the growth of A. woodii, and as for the production of demethylase. A. woodii was grown in “Balch” medium containing different carbon sources. Eleven substrates were tested including anisole, 2– and 3–methoxyphenol, vanilic acid, syringic acid, 2,3,4–, 2,4,5– and 3,4,5–trimethoxy benzoic acid and 2,3,4–, 2,4,5– and 3,4,5–trimethoxy benzyl alcohol. It was found that 2–methoxyphenol was the best substrate with a specific growth rate of 0.14 h–1. The production of demethylase induced cells was carried out in a chemostat culture at a dilution rate (D) of 0.08 h–1. Cells were harvested at steady state of growth and concentrated before use. Optimal concentration of 2–methoxvphenol as the sole carbon source was 0.62 g/L. Demethylation reaction of 0.31 g/L 2–methoxyphenol by induced culture increases 78% relative to the chemostat culture containing only fructose. Key words: Demethylation reaction; demethylase; harvested cells; methoxyaromatic; Acetobacteriumwoodii

Growth kinetics of Escherichia coli with galactose and several other sugars in carbon-limited chemostat culture

1999 ◽  
Vol 46 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Urs Lendenmann ◽  
Mario Snozzi ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Steady State ◽  
Specific Growth Rate ◽  
Growth Kinetics ◽  
Specific Growth ◽  
Chemostat Culture ◽  
Monod Model ◽  
E Coli ◽  
Kinetics Of

Kinetic models for microbial growth describe the specific growth rate (μ) as a function of the concentration of the growth-limiting nutrient (s) and a set of parameters. A typical example is the model proposed by Monod, where μ is related to s using substrate affinity (Ks) and the maximum specific growth rate (μmax). The preferred method to determine such parameters is to grow microorganisms in continuous culture and to measure the concentration of the growth-limiting substrate as a function of the dilution rate. However, owing to the lack of analytical methods to quantify sugars in the microgram per litre range, it has not been possible to investigate the growth kinetics of Escherichia coli in chemostat culture. Using an HPLC method able to determine steady-state concentrations of reducing sugars, we previously have shown that the Monod model adequately describes glucose-limited growth of E. coli ML30. This has not been confirmed for any other sugar. Therefore, we carried out a similar study with galactose and found steady-state concentrations between 18 and 840 μg·L-1 for dilution rates between 0.2 and 0.8·h-1, respectively. With these data the parameters of several models giving the specific growth rate as a function of the substrate concentration were estimated by nonlinear parameter estimation, and subsequently, the models were evaluated statistically. From all equations tested, the Monod model described the data best. The parameters for galactose utilisation were μmax = 0.75·h-1 and Ks = 67 μg·L-1. The results indicated that accurate Ks values can be estimated from a limited set of steady-state data when employing μmax measured during balanced growth in batch culture. This simplified procedure was applied for maltose, ribose, and fructose. For growth of E. coli with these sugars, μmax and Ks were for maltose 0.87·h-1, 100 μg·L-1; for ribose 0.57·h-1, 132 μg·L-1, and for fructose 0.70·h-1, 125 μg·L-1. Key words: monod model, continuous culture, galactose, glucose, fructose, maltose, ribose.

Effect of growth rate on the eicosapentaenoic acid and docosahexaenoic acid content of Isochrysis galbana in chemostat culture

1994 ◽  
Vol 41 (1) ◽  
pp. 23-27 ◽  
Author(s):  
E. Molina Grima ◽  
J. A. S�nchez P�rez ◽  
F. Garc�a Camacho ◽  
J. M. Fern�ndez Sevilla ◽  
F. G. Aci�n Fern�ndez
Keyword(s):  
Growth Rate ◽  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Acid Content ◽  
Chemostat Culture ◽  
Isochrysis Galbana

Effect of growth rate on the physiological rates of a chemostat-grown rotifer Encentrum linnhei

1988 ◽  
Vol 68 (1) ◽  
pp. 165-177 ◽  
Author(s):  
J. M. Scott
Keyword(s):  
Growth Rate ◽  
Oxygen Consumption ◽  
Steady State ◽  
Respiration Rate ◽  
Clearance Rate ◽  
Ingestion Rate ◽  
Physiological State ◽  
Growth Efficiency ◽  
Theoretical Figure ◽  
Marine Rotifer

The physiological rates of a normally omnivorous marine rotifer, Encentrum linnhei, were measured under the steady-state chemostat conditions in which the physiological state of the food-algae was kept constant whilst the rotifer growth rate was changed to preset levels. The specific clearance rate ranged between 50 and 100 μl/μg rotifer C/day (1.5–3.0 μ/rot/day) and varied hyperbolically with growth rate, a similar curve was obtained with the specific ingestion rate which varied between 1–2 μg C/μg rot C/day. A mean respiration rate of 0.45 μg C/μg rot C/day was obtained from oxygen consumption measurements. About 60‰ of ingested energy was found to be egested as paniculate matter and 9–4 °0 dissipated as heat, the latter comparing with a theoretical figure of 4–5‰.From rates, transfer efficiencies were obtained giving a mean net growth efficiency (K2) of 38‰ and a mean overall growth efficiency (K1 of 15‰. A curvilinear increase of Kl with growth rate contrasts with linear and hyperbolic responses found with brachionid rotifers.

scholarly journals Constitutively Up-regulated Carbon Metabolism is an Adaptation to Low Temperature in the Antarctic Psychrophile Chlamydomonas sp. UWO241

2021 ◽  
Author(s):  
Marina Cvetkovska ◽  
Beth Szyszka-Mroz ◽  
Nina Malczewski ◽  
David Smith ◽  
Norman P. A. Huner
Keyword(s):  
Growth Rate ◽  
Heat Stress ◽  
Steady State ◽  
Temperature Stress ◽  
Natural Habitat ◽  
Soluble Sugars ◽  
Physiological Characteristic ◽  
Rate Characteristic ◽  
The Antarctic ◽  
Chlamydomonas Sp

The Antarctic alga Chlamydomonas sp. UWO241 is an obligate psychrophile that thrives in the cold but is unable to survive at moderate, seemingly innocuous temperatures. We dissect the responses of UWO241 to temperature stress using global metabolomic approaches. UWO241 exhibits slow growth at 4°C, a temperature closest to its natural habitat, and faster growth at higher temperatures of 10-15°C. We demonstrate that the slower growth-rate characteristic of UWO241 at 4⁰C is not necessarily a hallmark of stress. UWO241 constitutively accumulates high levels of protective metabolites including soluble sugars, polyamines and antioxidants at a range of steady-state temperatures. In contrast, the mesophile Chlamydomonas reinhardtii accumulates these metabolites only during cold stress. Despite low growth rates, 4°C-grown UWO241 cultures had a higher capacity to respond to heat stress (24°C) and accumulated increased amounts of antioxidants, lipids and soluble sugars, when compared to cultures grown at 10-15°C. We conclude that the slower growth rate and the unique psychrophilic physiological characteristic of UWO241 grown at 4⁰C result in a permanently re-routed steady-state metabolism, which contributes to its increased resistance to heat stress. Our work adds to the growing body of research on temperature stress in psychrophiles, many of which are threatened by climate change.

scholarly journals Vegetative growth of Umbrella Leaf Palm, Johannesteijsmannia lanceolata in Angsi Forest Reserve, Malaysia

1970 ◽  
Vol 12 ◽  
pp. 11-20
Author(s):  
M. Z. Rozainah ◽  
U. R. Sinniah
Keyword(s):  
Growth Rate ◽  
Key Words ◽  
Vegetative Growth ◽  
Forest Reserve ◽  
Vegetative Phenology

A study of an acaulescent palm, Johannesteijsmannia  lanceolata J. Dransfield was carried out in Angsi Forest Reserve Negeri Sembilan Malaysia for a period of 19 months A total of 32 adults, 24 juveniles and 32 seedlings from 3 different plots were censused every two weeks. The results showed that the average numbers of new leaves entering the crown with in the study period (19months) were: 3.3, 2.6 and 1.3 for 2.1, 1.6 and 0.8 leaves per year for adult juvenile and seedling, respectively. From the calculation it was discovered that the time spent by each leaf in the crown before it died was 8.8 years for adult and 8.4 years for juvenile. Key words: Johannesteijsmannia; Growth rate; Vegetative phenology; Arecaceae doi: 10.3126/eco.v12i0.3190 Ecoprint: An International Journal of Ecology 12: 11-20, 2005

Environmentally Assisted Cracking of Subsea Pipelines in Oil & Gas Production Environments—Effect of Static Loading

CORROSION ◽  
10.5006/2896 ◽  
2020 ◽  
Vol 76 (3) ◽  
pp. 312-323
Author(s):  
Ramgopal Thodla ◽  
Feng Gui ◽  
Colum Holtam
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Steady State ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Tip ◽  
Metal Dissolution ◽  
Low Frequencies ◽  
Static Crack

Fatigue crack growth rate of line pipe steels in sour environments typically exhibits a steady-state value at low frequencies. However, in highly inhibited sour environments, there is no evidence of a steady-state fatigue crack growth at low frequencies. This is likely a result of static crack growth rate at Kmax. Stable static crack growth measured under constant stress intensity factor (K) conditions in inhibited sour environments was in the range of 10−7 mm/s to 10−8 mm/s. The crack growth rate in inhibited sour environments is likely associated with crack tip processes associated with metal dissolution/film formation and associated hydrogen evolution. The results obtained were modeled based on a crack tip strain rate based approach, where the rate limiting step was the metal dissolution/FeS formation and the corresponding hydrogen generation reaction.

ASSESSMENT OF COMPLETELY PELLETED DIETS FOR PERFORMANCE TESTING OF RAMS

1986 ◽  
Vol 66 (3) ◽  
pp. 817-820
Author(s):  
J. S. WALTON ◽  
B. W. McBRIDE ◽  
N. A. MARTINEAU ◽  
T. D. BURGESS
Keyword(s):  
Growth Rate ◽  
Key Words ◽  
Performance Test ◽  
Performance Testing ◽  
Ingestive Behavior ◽  
Test Procedures

Completely pelleted diets were fed to rams under a facsimile of Ontario Ram Performance Test procedures. Twenty rams were fed for 50 d on completely pelleted rations without impairment of growth rate and without any effects on rumen health or ingestive behavior. Key words: R.O.P. testing, rams, pelleted feeds, growth rate, rumen lining

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