scholarly journals Dependence of the element composition ofK. pneumoniae on the steady-state specific growth rate

1982 ◽  
Vol 24 (6) ◽  
pp. 1445-1449 ◽  
Author(s):  
A. A. Esener ◽  
J. A. Roels ◽  
N. W. F. Kossen
1999 ◽  
Vol 46 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Urs Lendenmann ◽  
Mario Snozzi ◽  
Thomas Egli

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.


Aquaculture ◽  
2008 ◽  
Vol 274 (1) ◽  
pp. 87-95 ◽  
Author(s):  
S. Millot ◽  
M.-L. Bégout ◽  
J. Person-Le Ruyet ◽  
G. Breuil ◽  
C. Di-Poï ◽  
...  

2010 ◽  
Vol 45 (11) ◽  
pp. 1800-1807 ◽  
Author(s):  
S. Chenikher ◽  
J.S. Guez ◽  
F. Coutte ◽  
M. Pekpe ◽  
P. Jacques ◽  
...  

2012 ◽  
Vol 48 (2) ◽  
pp. 382-386 ◽  
Author(s):  
Juan Aguirre ◽  
Mª Rosa Rodríguez ◽  
Rodrigo González ◽  
Gonzalo García de Fernando

1999 ◽  
Vol 70 (1-3) ◽  
pp. 323-333 ◽  
Author(s):  
Marcel Janssen ◽  
Tjibbe Chris Kuijpers ◽  
Bram Veldhoen ◽  
Michel Brik Ternbach ◽  
Johannes Tramper ◽  
...  

2013 ◽  
Vol 48 (6) ◽  
pp. 645-650 ◽  
Author(s):  
Cleujosí da Silva Nunes ◽  
Gilberto Moraes ◽  
Fernando Fabrizzi ◽  
Araceli Hackbarth ◽  
Gustavo Alberto Arbeláez-Rojas

The objective of this work was to evaluate the effect of sustained swimming and dietary protein levels on growth and hematological responses of juvenile pacu (Piaractus mesopotamicus). A completely randomized design was used in a 3x2 factorial arrangement, with three levels of dietary protein (24, 28, and 32% crude protein), two rearing conditions (sustained swimming or motionless water), and 15 replicates. Fish were subjected to sustained swimming at the velocity of two body lengths per second (2 BL s-1), for 45 days. The level of dietary protein and the swimming conditions affected the performance, growth, and hematological profile of pacu. Swimming conditions influenced nutritional factors, increasing daily weight gain, specific growth rate, number of erythrocytes, mean corpuscular volume, and mean corpuscular hemoglobin. Fish under sustained swimming and fed with 24% crude protein showed better growth performance, with higher specific growth rate (4.11±0.88) and higher daily weight gain (2.19±0.47 g per day). Sustained swimming can increase the productive performance of pacu and simultaneously reduce dietary protein levels.


Author(s):  
Dio Patria Yustysi ◽  
Fajar Basuki ◽  
Titik Susilowati ◽  
Tristiana Yuniarti

ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh dari hibridisasi ikan nila Pandu F6 dengan nila Nilasa terhadap karakter reproduksinya dan performa benih yang dihasilkan. Penelitian ini dilakukan dengan metode eksperimental menggunakan Rancangan Acak Lengkap (RAL) dengan 4 perlakuan dan 3 kali ulangan. Perlakuan dalam penelitian ini: perlakuan A (Pandu F6 ♀><Pandu F6 ♂), B (Nilasa ♀><Nilasa ♂), C (Pandu F6 ♀>< Nilasa ♂), dan D (Nilasa ♀><Pandu F6 ♂). Data yang diamati meliputi fekunditas, daya tetas telur, diameter dan bobot telur, panjang dan bobot larva TL, panjang dan bobot larva lepas kuning telur, kelulushidupan, laju pertumbuhan spesifik, konversi pakan dan kualitas air. Hasil penelitian menunjukan nilai terbaik pada fekunditas sebesar 1191,67 ± 239,45 butir/200 g, daya tetas telur sebesar 80,93 ± 3,90%, kelulushidupan sebesar 81,55 ± 7,54%, laju pertumbuhan spesifik sebesar 7,26 ± 0,25, konversi pakan 0,54 ± 0,02 didapatkan pada perlakuan C, akan tetapi untuk diameter dan bobot telur, panjang dan bobot larva Kuning Telur, dan panjang dan bobot larva lepas kuning telur tidak berbeda nyata. Hasil tersebut menunjukan bahwa hibridisasi (perlakuan C) memberikan pengaruh yang nyata (P < 0,05) terhadap fekunditas, daya tetas telur, kelulushidupan, laju pertumbuhan spesifik, dan konversi pakan tetapi tidak berpengaruh terhadap diameter dan bobot telur, panjang dan bobot larva, dan panjang dan bobot larva lepas kuning telur. Kata kunci: Hibridisasi, Ikan Nila, Karakter Reproduksi, Performa Benih  ABSTRACT This research aims to know the influence of hybridization tilapia fish Pandu F6 with nila Nilasa against the character of the reproduction and seed performance. This research was conducted with the experimental method using Random Design complete (RAL) with 4 treatments and three replicates. The treatments in this study: the treatment A (Pandu F6 F6 ♀ >< Pandu ♂), B (Nilasa ♀>< Nilasa ♂), C (Pandu F6 ♀>< Nilasa ♂), and D (Nilasa ♀ >< Pandu F6 ♂). The observed data covering fecundity, hatching rate, egg size, yolk sack larva length and weight, length and weight of the egg yolk off larvae, survival rate, specific growth rate, feed conversion rate, and water quality. The results showed the best value on the fecundity of 1191.67±239.45 eggs/200 g, Hatching rate 80.93 ± 3.90%, Survival rate of 81.55 ± 7.54%, specific growth rate of 7.26 ± 0.25, conversion fodder 0.54 ± 0.02 obtained at the treatment C, but for the diameter and weight of egg, larval length and weight TL, and the length and weight of the yolk egg off larvae for each treatment do not differ markedly. The results showed that hybridization (treatment C) gives a real influence (P < 0.05) of fecundity,hatching rate, survival rate but not with the egg size, larva weight and length, and the length and weight of larvae off yolk. Water quality on the spawning, hatching eggs and larvae found on the maintenance of a decent range for tilapia fish farming Keywords: hybridization, tilapia fish, character of the reproduction, seed performance 


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