Competition between strains of Escherichia coli with and without plasmid RP4 during chemostat growth

1991 ◽  
Vol 37 (7) ◽  
pp. 509-512 ◽  
Author(s):  
Zuhair Numan ◽  
W. A. Venables ◽  
J. W. T. Wimpenny
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Key Words ◽  
Growth Kinetic ◽  
Initial Period ◽  
Kinetic Constants ◽  
Continuous Cultures ◽  
The Difference ◽  
Selection Of ◽  
Period Of Oscillation

Escherichia coli strains J53(nal) and J53(RP4) were grown together in glucose-limited continuous cultures. Based on the measured growth kinetic constants of the two strains, take-over of the cultures by J53(RP4) was predicted. However, in practice, an initial period of predominance by J53(RP4) was always followed by a prolonged period in which relative numerical proportions of the two strains oscillated widely. This period of oscillation was removed or greatly reduced when the difference between the predicted growth-rate potentials of the two strains was increased by selection of a chemostat-adapted variant of J53(RP4). Key words: competition, chemostat, plasmid, Escherichia coli.

Phase Formation and Growth Kinetics of an Interface Layer in Ni/SiC

2008 ◽  
Vol 600-603 ◽  
pp. 631-634
Author(s):  
Kenichiro Terui ◽  
Atsuko Sekiguchi ◽  
Hiroshi Yoshizaki ◽  
Junichi Koike
Keyword(s):  
Growth Rate ◽  
Late Stage ◽  
Growth Kinetic ◽  
Early Stage ◽  
Interface Reaction ◽  
Interface Layer ◽  
Nickel Silicide ◽  
Composition And Structure ◽  
The Difference ◽  
Kinetics Of

The reaction behavior and growth kinetic of reaction layer were investigated in the Ni contact to n-type 6H-SiC. Annealing was performed at temperature in the range between 800 and 1000 °C for 1 to 240 minutes in Ar atmosphere. The interface reaction of Ni/SiC starts with Ni diffusion into SiC. Ni3Si is initially precipitated and subsequently forms the continuous layer of d-Ni2Si. Kirkendall voids are formed at the reaction front. Carbon is segregated in the interface layer of nickel silicide. The growth rate of the interface layer follows a parabolic law, meaning that the growth rate is controlled by diffusion. The growth occurs in two steps at all examined temperatures: a fast growth is followed by a slow growth. In addition, in the late stage, the growth rate changes dramatically below and above 850°C. The observed growth kinetic can be explained by the difference of Ni diffusivity and the required concentration change for phase transition depending on the phase composition and structure. The d-Ni2Si is formed in the early stage, while the e-Ni3Si2 and q-Ni2Si are formed in the late stage below and above 850°C, respectively.

scholarly journals Patogen Penyakit Busuk Buah Kakao: Karakter dan Patogenisitas Phytophthora palmivora Isolat Asal Pakuwon, Sukabumi

2021 ◽  
Vol 8 (1) ◽  
pp. 49
Author(s):  
Wartono Wartono ◽  
Efi Taufiq
Keyword(s):  
Growth Rate ◽  
Average Length ◽  
Petri Dish ◽  
Phytophthora Palmivora ◽  
Pathogenicity Test ◽  
Mating Types ◽  
Randomized Design ◽  
The Difference ◽  
Colony Shape ◽  
Selection Of

Phytophthora palmivora (Butl.)<em> is a major obstacle in cocoa cultivation worldwide. The study aimed to determine the morphological character and pathogenicity of P. palmivora Pakuwon isolate. The study was carried out from November 2020 to January 2021, which consisted of 3 activities e.g. (1) pathogen isolation, tests on growth rate and colony formation, and stimulation of sporangia, zoospore, and clamydospore formation, which was performed  in CMA, PDA, and mung bean media. The parameters observed were colony shape, growth rate, shape and size of sporangia, papillae, and sporangiophores, also chlamydospore and hyphal diameters; (2) To determine the possibility of different mating types, two isolates were grown on CMA medium in one petri dish; (3) The pathogenicity test, using a detached fruit assay by inoculating the cocoa pods with mycelium plug and zoospores. The patogenicity test was conducted in a completely randomized design with 4 replications, and the parameter observed was the area of </em><em>the spot. The isolation obtained 3 isolates, the mycelium of all three isolates showed white in color, cottony, and  no pattern in shape. The diameters of hyphae and chlamydospores were 5.6 - 6.3 mm and 39.0 - 43.2 mm, respectively. The sporangia were ovoid, ellipsoid, subsperic, obpyriform, and irregular. Sporangia measured 5.6 - 60.1 mm in length and 30.4 - 32.9 mm in width. Papillae were obviously visible with an average length of 6.8 mm. Test on mating types showed no oospores formed. PPkw1 isolates showed higher growth rates and more pathogenic than PPkw2 and PPkw3. The difference of pathogenicity of each </em>P. palmivora<em> isolates originated from Pakuwon can be used for selection of cocoa resistance in the future.</em>

scholarly journals Detection of Uropathogens by Using Chromogenic Media (Hicrome UTI agar), CLED agar and other Conventional Media

1970 ◽  
Vol 6 (1) ◽  
pp. 46-50 ◽  
Author(s):  
R Parveen ◽  
SK Saha ◽  
SM Shamshuzzaman ◽  
AL Rashid ◽  
A Chowdhury ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Key Words ◽  
Blood Agar ◽  
Macconkey Agar ◽  
Isolation And Identification ◽  
Enterococcus Spp ◽  
Presumptive Identification ◽  
Agar Media ◽  
Better Than

This study was undertaken to find media better than routinely used media in isolation of uropathogens.Three hundred urine samples having pus cells >_ 5/ HPF were enrolled for the study. Comparison of isolation and identification of uropathogens among HiCrome UTI Agar media, 5% Sheep Blood agar & MacConkey agar and CLED agar media were done. Among them 95(31.67%) samples showed single growth, 6 (2%) showed mixed growth and 199 (66.67%) showed no growth. Rate of presumptive identification of organisms in primary culture plate were high in HiCrome UTI agar media. For Escherichia coli, it was 94.20% whereas in CLED agar it was 79.71% and by Blood agar and MacConkey agar media in combination it was 82.61%. All the Enterococcus spp. were identified in HiCrome UTI agar media, 33.33% in CLED agar media but none in Blood agar and MacConkey agar media. Among the mixed growth, 100% organisms were identified on HiCrome UTI Agar media due to distinct colour produced by the different organisms, whereas in one (16.67%) sample (mixed Esch.coli and Pseudomonas spp.) organisms were identified on other three media. Key words: UTI; Uropathogen; HiCrome UTI Agar media DOI: 10.3329/fmcj.v6i1.7411 Faridpur Med. Coll. J. 2011;6(1): 46-50

A DIFFERENCE IN WEIGHT REDUCES FIGHTING WHEN UNACQUAINTED NEWLY WEANED PIGS FIRST MEET

1987 ◽  
Vol 67 (4) ◽  
pp. 951-960 ◽  
Author(s):  
JEFFREY RUSHEN
Keyword(s):  
Growth Rate ◽  
Aggressive Behavior ◽  
Key Words ◽  
Coefficient Of Variation ◽  
Weaned Pigs ◽  
Common Procedure ◽  
Variation Formula ◽  
Weight Variation ◽  
The Common ◽  
The Difference

The mixing of weaned pigs from different litters was observed so that the effect of a large difference in bodyweight on fighting could be examined. When 5- to 6-wk-old pigs met in pairs for 1 h, fights were longer and biting more frequent if the difference in weight between the pigs was small (< 0.5 kg) than if it was large (> 3.0 kg). In groups of four 5- to 6-wk-old pigs taken from different litters, fighting was more prolonged during 2 h after mixing if there was little weight variation in the group (coefficient of variation [Formula: see text]) than if there was large weight variation (coefficient of variation [Formula: see text]). When groups of four pigs were formed by taking one large and one small pig from each of two litters, the longest duration of fighting occurred between the two large pigs. Significantly less fighting occurred between the large and small pigs and between the two smaller pigs. Subordinate pigs were less likely to retaliate against the dominant pigs if the weight difference was large. It seemed that the presence of large pigs in the group inhibited fighting between equally matched smaller pigs. I suggest the common procedure of mixing pigs matched for weight exacerbates the initial fighting but how this affects growth rate will depend on the level of competition over food. Key words: Pigs, aggressive behavior, weight variation, mixing

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

The selection of optimum fermentation condition for improved expression of sumo-il11 in escherichia coli

2015 ◽  
Vol 37 (1se) ◽  
Author(s):  
Nguyen Thi Quy ◽  
Duong Thu Huong ◽  
Dang Thi Ngoc Ha ◽  
Le Thi Thu Hong ◽  
Do Thi Huyen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Fermentation Condition ◽  
Selection Of
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