scholarly journals Determination of Specific Growth Rate by Measurement of Specific Rate of Ribosome Synthesis in Growing and Nongrowing Cultures of Acinetobacter calcoaceticus

2007 ◽  
Vol 74 (3) ◽  
pp. 901-903 ◽  
Author(s):  
Matthew R. Cutter ◽  
Peter G. Stroot
Keyword(s):  
Growth Rate ◽  
16S Rrna ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Acinetobacter Calcoaceticus ◽  
Microbial Populations ◽  
Specific Rate ◽  
Ribosome Synthesis ◽  
Good Agreement

ABSTRACT RT-RiboSyn measures the specific rate of ribosome synthesis in distinct microbial populations by measuring the generation rate of precursor 16S rRNA relative to that of mature 16S rRNA when precursor 16S rRNA processing is inhibited. Good agreement was demonstrated between specific rate of ribosome synthesis and specific growth rate of Acinetobacter calcoaceticus.

The effect of specific growth rate on protein synthesis and secretion in the filamentous fungus Trichoderma reesei

Microbiology ◽  
2005 ◽  
Vol 151 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Tiina M. Pakula ◽  
Katri Salonen ◽  
Jaana Uusitalo ◽  
Merja Penttilä
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Specific Growth Rate ◽  
Trichoderma Reesei ◽  
Growth Rates ◽  
Protein Production ◽  
Specific Growth ◽  
Synthesis Rate ◽  
Specific Rate ◽  
Specific Growth Rates

Trichoderma reesei was cultivated in chemostat cultures on lactose-containing medium. The cultures were characterized for growth, consumption of the carbon source and protein production. Secreted proteins were produced most efficiently at low specific growth rates, 0·022–0·033 h−1, the highest specific rate of total protein production being 4·1 mg g−1 h−1 at the specific growth rate 0·031 h−1. At low specific growth rates, up to 29 % of the proteins produced were extracellular, in comparison to only 6–8 % at high specific growth rates, 0·045–0·066 h−1. To analyse protein synthesis and secretion in more detail, metabolic labelling of proteins was applied to analyse production of the major secreted protein, cellobiohydrolase I (CBHI, Cel7A). Intracellular and extracellular labelled CBHI was quantified and analysed for pI isoforms in two-dimensional gels, and the synthesis and secretion rates of the molecule were determined. Both the specific rates of CBHI synthesis and secretion were highest at low specific growth rates, the optimum being at 0·031 h−1. However, at low specific growth rates the secretion rate/synthesis rate ratio was significantly lower than that at high specific growth rates, indicating that at low growth rates the capacity of cells to transport the protein becomes limiting. In accordance with the high level of protein production and limitation in the secretory capacity, the transcript levels of the unfolded protein response (UPR) target genes pdi1 and bip1 as well as the gene encoding the UPR transcription factor hac1 were induced.

Estimating Bacterial Growth Parameters by Means of Detection Times

1999 ◽  
Vol 65 (2) ◽  
pp. 732-736 ◽  
Author(s):  
József Baranyi ◽  
Carmen Pin
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Bacterial Growth ◽  
Specific Growth ◽  
Growth Parameters ◽  
Physiological State ◽  
Cell Number ◽  
Maximum Specific Growth Rate ◽  
Specific Rate ◽  
The Individual

ABSTRACT We developed a new numerical method to estimate bacterial growth parameters by means of detection times generated by different initial counts. The observed detection times are subjected to a transformation involving the (unknown) maximum specific growth rate and the (known) ratios between the different inoculum sizes and the constant detectable level of counts. We present an analysis of variance (ANOVA) protocol based on a theoretical result according to which, if the specific rate used for the transformation is correct, the transformed values are scattered around the same mean irrespective of the original inoculum sizes. That mean, termed the physiological state of the inoculum,α̂, and the maximum specific growth rate, μ, can be estimated by minimizing the variance ratio of the ANOVA procedure. The lag time of the population can be calculated as λ = −ln α̂/μ; i.e. the lag is inversely proportional to the maximum specific growth rate and depends on the initial physiological state of the population. The more accurately the cell number at the detection level is known, the better the estimate for the variance of the lag times of the individual cells.

scholarly journals Determination of Suitable Water Salinity and Live Food in The Rearing of Eel (Anguilla bicolor) Fry

2008 ◽  
Vol 7 (1) ◽  
pp. 71
Author(s):  
. Sutrisno
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Conversion Ratio ◽  
Live Food ◽  
Water Salinity ◽  
Food Conversion ◽  
Food Conversion Ratio

<p>This study was conducted to determine suitable water salinity and live food in the rearing of eel,  <em>Anguilla bicolor </em>fry.  Eel fry in weight of 0.15±0.008 g/tail were reared at controlled tank at density of 2 fish liter<sup>-1</sup> for 42 days.  Experiment was devided into two steps.  In the first step of experiment, eel fry were reared at different water salinity, i.e., 0; 5; 10 and 15 ppt.  Fish were fed on <em>Tubifex</em> at satiation.  The best result from the first experiment was then used in the second step of study to examine proper live food for eel fry.  Fish were fed on live food (<em>Tubifex</em>, <em>Artemia</em>, or <em>Spirulina</em>) at 10% body weight.  Survival rate, specific growth rate and food conversion ratio were observed.  The result of experiment showed that survival rate of eel fry reared in water salinity of 5 ppt (100%), 10 (96%) and 15 ppt (97%) was higher (p<0.05) compared to that of 0 ppt (58%).  Specific growth rate was also higher (p<0.05) in fish reared in water salinity of 5 (2.33%), 10 (1.65%) and 15 ppt (1.57%) compared to that of 0 ppt (0.022%).  Survival rate and specific growth rate of fish at treatment of 5, 10 and 15 ppt were insignificantly different (p>0.05).  The best food conversion ratio was also being obtained at treatment of 5 ppt (3.36), followed repectively by 10 ppt (5.11), 15 ppt (5.70) and 0 ppt (21.11).  No different survival rate of eel fry by feeding on different live food was obtained.  Higher specific growth rate was achieved at feeding of <em>Artemia</em> (2.82% per day), followed respectively by <em>Tubifex </em>(1.85% per day) and <em>Spirulina </em>(0.15% per day).  Food coversion ratio in each treatment was 4.42, 2.77 and 134.33, respectively.</p> <p>Keywords:  eel, salinity, live food</p> <p> </p> <h5>ABSTRAK</h5> <p>Penelitian dilakukan dengan tujuan untuk mengetahui salinitas air dan jenis pakan alami yang tepat dalam pemeliharaan benih ikan sidat <em>(Anguilla bicolor)</em>. Benih sidat dengan berat rata-rata 0,15±0,008 g/ekor dipelihara selama 42 hari pada wadah terkontrol dengan kepadatan 2 ekor/liter. Penelitian dibagi kedalam dua tahap. Pada tahap pertama benih sidat diperlihara pada media dengan salinitas 0; 5, 10 dan 15 ppt.  Pakan alami berupa cacing sutera diberikan secara satiasi.  Salinitas terbaik hasil penelitian tahap pertama digunakan pada penelitian tahap kedua untuk mengetahui jenis pakan alami (cacing sutera <em>Tubifex</em>, <em>Artemia</em>, atau <em>Spirulina</em>) yang cocok untuk benih sidat.  Pakan diberikan sebanyak 10% bobot tubuh.   Paramater yang diamati meliputi sintasan, laju pertumbuhan spesifik dan efisiensi pakan.  Hasil penelitian menunjukkan  bahwa sintasan benih ikan sidat yang dipelihara pada salinitas 5 (100%), 10 (96%) dan 15 ppt (97%) lebih tinggi (p<0,05) daripada yang dipelihara pada salinitas 0 ppt (58%).  Laju pertumbuhan spesifik juga lebih tinggi (p<0,05) pada benih yang dipelihara pada salinitas 5 (2,33%), 10 (1,65%) dan 15 ppt (1,57%) dibandingkan dengan salinitas 0 ppt (0,022%).  Sintasan dan laju pertumbuhan spesifik antara perlakuan 5, 10 dan 15 ppt tidak berbeda nyata (p>0,05). Konversi pakan terbaik juga diperoleh pada perlakuan 5 ppt (3,36), diikuti berturut-turut 10 ppt (5,11), 15 ppt (5,70) dan 0 ppt (21,11).  Pemberian pakan alami yang berbeda tidak berpengaruh terhadap sintasan benih sidat, tetapi berpengaruh terhadap pertumbuhan.  Pemberian <em>Artemia</em> memberikan laju pertumbuhan spesifik tertinggi, yaitu 2,82%/hari, <em>Tubifex </em>(1,85%/hari) dan <em>Spirulina </em>(0,15%/hari).  Konversi pakan tiap perlakuan berturut-turut adalah  4,42; 2,77 dan 134,33.</p> Kata kunci:  ikan sidat, salinitas, pakan alami

The Growth of Brown Trout (Salmo Trutta Linn.)

1946 ◽  
Vol 22 (3-4) ◽  
pp. 130-144
Author(s):  
MARGARET E. BROWN
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Rapid Growth ◽  
Salmo Trutta ◽  
Specific Growth ◽  
Condition Factor ◽  
Specific Rate ◽  
Annual Growth Rate ◽  
Size Hierarchy ◽  
Rate Of Growth

1. Two-year-old trout were grown in environments where the following factors were controlled: temperature, amount and intensity of illumination, rate of flow, composition and aeration of the water, quality and quantity of food and amount of living space. 2. The specific growth rate of an individual depended on its size relative to that of the others in the group. It is suggested that subgroups of four or five individuals existed within the size hierarchy and were reorganized at intervals of about 3 months. 3. There was an optimum degree of crowding for rapid growth, and overcrowding led to lower appetite and efficiency of utilization of food, while under-crowded trout ate and grew erratically. 4. In spite of constant environmental conditions, all the fish had an annual growth-rate cycle, with an autumn check, a spring maximum, rapid summer growth and another autumn check, which coincided with maturation of the gonads when they became 3 years old. 5. Individual specific growth rates fluctuated over periods of 4-6 weeks, and rapid growth in length alternated with rapid growth in weight. The specific rate of growth in length was directly proportional to the condition factor. The amount of food eaten, the efficiency of utilization of food and the specific rate of growth in weight varied with the condition factor and were maximal for a factor of about 1·10. 6. The growth-rate fluctuations were exaggerated and the efficiency was greater when the food supply was restricted. At the maintenance level the change in weight was directly proportional to the amount of food eaten. The maintenance requirement decreased, relatively, with increase in body weight. 7. The mean specific growth rate was higher with less than 12 hr. per diem of the standard illumination.

The Growth of Brown trout (Salmo Trutta Linn.)

1946 ◽  
Vol 22 (3-4) ◽  
pp. 118-129
Author(s):  
MARGARET E. BROWN
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Rates ◽  
Salmo Trutta ◽  
Specific Growth ◽  
Specific Rate ◽  
Size Hierarchy ◽  
Living Space ◽  
Brown Trout Salmo Trutta ◽  
Specific Growth Rates

1. Groups of trout fry of the same parentage were grown in environments where the following factors were controlled: temperature, amount and intensity of illumination, rate of water flow, aeration and chemical composition of the water, amount of living space and quality of food supply. They were allowed to eat as much as they would, and individual weights were recorded during the first 8 months after the beginning of feeding. 2. There was soon an increase in the range of individual weight in each group of fry, and thereafter the larger fry grew faster than smaller ones. When the larger fry were removed, the smaller ones grew at an increased specific rate, and when larger fry were added, the smaller ones grew more slowly. It is suggested that a ‘size hierarchy’ was established within each group, and an individual's specific growth rate depended on its position in the order of decreasing weight. 3. There was an optimum degree of crowding for maximum productivity. Compared with the fry in this group, the specific growth rates of individuals in larger, more crowded groups depended on the number of fish of larger size, while in smaller, less crowded groups, individuals grew at rates depending on the proportion of fish which were larger and smaller. 4. Alevin weight had little effect on the specific growth rates of fry. 5. There were differences between the growth histories of fry derived from alevins of the same weight and descended from the same father but different mothers (all of the same stock, age and size). 6. The specific growth rates decreased as the fry grew older, but there was no correlation between body weight and specific growth rate, except for the size hierarchy effect within each group. This effect had a greater influence on the size of individual fry than had either alevin weight or heredity.

scholarly journals Growth Kinetics of Hyphomicrobium and Thiobacillus spp. in Mixed Cultures Degrading Dimethyl Sulfide and Methanol

2010 ◽  
Vol 76 (16) ◽  
pp. 5423-5431 ◽  
Author(s):  
Alexander C. Hayes ◽  
Steven N. Liss ◽  
D. Grant Allen
Keyword(s):  
Growth Rate ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Specific Growth Rate ◽  
Growth Kinetics ◽  
Growth Rates ◽  
Dimethyl Sulfide ◽  
Specific Growth ◽  
Rrna Gene ◽  
Kinetics Of

ABSTRACT The growth kinetics of Hyphomicrobium spp. and Thiobacillus spp. on dimethyl sulfide (DMS) and methanol (in the case of Hyphomicrobium spp.) in an enrichment culture created from a biofilter cotreating DMS and methanol were studied. Specific growth rates of 0.099 h−1 and 0.11 h−1 were determined for Hyphomicrobium spp. and Thiobacillus spp., respectively, growing on DMS at pH 7. These specific growth rates are double the highest maximum specific growth rate for bacterial growth on DMS reported to date in the literature. When the pH of the medium was decreased from pH 7 to pH 5, the specific growth rate of Hyphomicrobium spp. decreased by 85%, with a near 100-fold decline in the yield of Hyphomicrobium 16S rRNA gene copies in the mixed culture. Through the same pH shift, the specific growth rate and 16S rRNA gene yield of Thiobacillus spp. remained similar. When methanol was used as a substrate, the specific growth rate of Hyphomicrobium spp. declined much less over the same pH range (up to 30%) while the yield of 16S rRNA gene copies declined by only 50%. Switching from an NH4 +-N-based source to a NO3 −-N-based source resulted in the same trends for the specific growth rate of these microorganisms with respect to pH. This suggests that pH has far more impact on the growth kinetics of these microorganisms than the nitrogen source. The results of these mixed-culture batch experiments indicate that the increased DMS removal rates observed in previous studies of biofilters cotreating DMS and methanol are due to the proliferation of DMS-degrading Hyphomicrobium spp. on methanol at pH levels not conducive to high growth rates on DMS alone.

scholarly journals Microbial Interactions between Amylolytic and Non-Amylolytic Lactic Acid Bacteria Strains Isolated during the Fermentation of Pozol

2021 ◽  
Author(s):  
Sandra Bolaños-Nuñez ◽  
Jorge A. Santiago-Urbina ◽  
Jean-Pierre Guyot ◽  
Gloria Díaz-Ruiz ◽  
Carmen Wacher
Keyword(s):  
Growth Rate ◽  
Lactic Acid ◽  
Specific Growth Rate ◽  
Kinetic Parameters ◽  
Acid Production ◽  
Specific Growth ◽  
Lactic Acid Production ◽  
Amylolytic Activity ◽  
Specific Rate ◽  
Acid Yield

Pozol is a Mexican beverage prepared from fermented nixtamalized maize dough. To contribute to understanding its complex microbial ecology, the effect of inoculating on MRS-starch pure and mixed cultures of amylolytic Sii-25124 and non-amylolytic W. confusa 17, isolated from pozol, were studied on their interactions and fermentation parameters. These were compared with L. plantarum A6, an amylolytic strain isolated from cassava. Microbial growth, kinetic parameters, amylolytic activity, lactic acid production, and hydrolysis products from starch fermentation were measured. The population dynamics were followed by qPCR. L. plantarum A6 showed higher enzymatic activity, lactic acid, biomass production, and kinetic parameters than pozol LAB in pure cultures. Mixed culture of each pozol LAB with L. plantarum A6 showed a significant decrease in amylolytic activity, lactic acid yield, specific growth rate, and specific rate of amylase production. The interaction between Sii-25124 and W. confusa 17 increased the global maximum specific growth rate (&micro;), the lactic acid yield from starch (Ylac/s), lactic acid yield from biomass (Ylac/x), and specific rate of lactic acid production (qlac) by 15, 30, 30, and 40%, respectively compared with the pure culture of Sii-25124. Interactions between the two strains are essential for this fermentation.

scholarly journals Dynamics Modeling of Nitrogen Compounds in Microalgae Cells. 2. Chemostat

2019 ◽  
Vol 14 (2) ◽  
pp. 450-463 ◽  
Author(s):  
A.S. Lelekov ◽  
R.P. Trenkenshu
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Nitrogen Compounds ◽  
Specific Rate ◽  
Dynamics Modeling ◽  
Cell Content ◽  
Classical Models ◽  
Species Specific ◽  
Maximum Specific Rate

The work focuses on dynamics modeling of nitrogen compounds in microalgae cells under chemostat conditions. The analysis of classical models (Michaelis-Menten, Monod, Droop), which describe the kinetics of substrate-dependent growth of microalgae, was carried out. Classical models are shown to be applicable provided that the physicochemical parameters of the medium such as temperature, cell irradiation, etc are constant. As an alternative approach, the possibility of using linear splines in kinetics modeling of nitrate absorption by microalgae is shown. For the conditions of the chemostat, particular solutions for the generalized model of the dynamics of nitrogen compounds in the cells of microalgae considered in the first part of the work were obtained, and boundary conditions for the culture growth at unlimited nitrogen were determined. For limited growth, the equation for both the dependence of the specific growth rate on the intracellular nitrogen content, which coincides in form with the Droop model and the dependence of the specific growth rate on the extracellular concentration of nitrogen, which coincides in form with the Monod model were obtained. The species-specific coefficients of the equations such as the maximum specific rate of nitrogen absorption, the maximum specific rate of synthesis of structural components, the maximum content of reserve forms of nitrogen, the minimum share of structural forms of nitrogen in the total cell content were determined.

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