Growth characteristics of three Mallomonas species (silica-scaled chrysophytes) at different temperatures and pH

2007 ◽  
Vol 25 (1-2) ◽  
pp. 113-118
Author(s):  
Kyung Lak Lee ◽  
Ho-Sung Yoon ◽  
Yong Jae Kim ◽  
Han Soon Kim
Keyword(s):  
Growth Characteristics ◽  
Scaled Chrysophytes ◽  
Different Temperatures

scholarly journals Cultivation and Growth Characteristics of a Diverse Group of Oligotrophic Marine Gammaproteobacteria

2004 ◽  
Vol 70 (1) ◽  
pp. 432-440 ◽  
Author(s):  
Jang-Cheon Cho ◽  
Stephen J. Giovannoni
Keyword(s):  
Growth Characteristics ◽  
Rrna Gene ◽  
Natural Seawater ◽  
Nutrient Media ◽  
Physiological Properties ◽  
The Pacific ◽  
Single Clade ◽  
High Nutrient ◽  
Different Temperatures ◽  
The Pacific Ocean

ABSTRACT Forty-four novel strains of Gammaproteobacteria were cultivated from coastal and pelagic regions of the Pacific Ocean using high-throughput culturing methods that rely on dilution to extinction in very low nutrient media. Phylogenetic analysis showed that the isolates fell into five rRNA clades, all of which contained rRNA gene sequences reported previously from seawater environmental gene clone libraries (SAR92, OM60, OM182, BD1-7, and KI89A). Bootstrap analyses of phylogenetic reliability did not support collapsing these five clades into a single clade, and they were therefore named the oligotrophic marine Gammaproteobacteria (OMG) group. Twelve cultures chosen to represent the five clades were successively purified in liquid culture, and their growth characteristics were determined at different temperatures and dissolved organic carbon concentrations. The isolates in the OMG group were physiologically diverse heterotrophs, and their physiological properties generally followed their phylogenetic relationships. None of the isolates in the OMG group formed colonies on low- or high-nutrient agar upon their first isolation from seawater, while 7 of 12 isolates that were propagated for laboratory testing eventually produced colonies on 1/10 R2A agar. The isolates grew relatively slowly in natural seawater media (1.23 to 2.63 day−1), and none of them grew in high-nutrient media (>351 mg of C liter−1). The isolates were psychro- to mesophilic and obligately oligotrophic; many of them were of ultramicrobial size (<0.1 μm3). This cultivation study revealed that sporadically detected Gammaproteobacteria gene clones from seawater are part of a phylogenetically diverse constellation of organisms mainly composed of oligotrophic and ultramicrobial lineages that are culturable under specific cultivation conditions.

Growth rates of Rhizobium trifolii and Rhizobium lupini in sterilized soils

1968 ◽  
Vol 19 (6) ◽  
pp. 919 ◽  
Author(s):  
M/S Chowdhury ◽  
KC Marshall ◽  
CA Parker
Keyword(s):  
Sandy Soil ◽  
Growth Rates ◽  
Host Plants ◽  
Sandy Loam ◽  
Growth Characteristics ◽  
Rhizobium Trifolii ◽  
Optimum Temperature ◽  
Different Temperatures ◽  
Rhizobium Lupini

The growth characteristics of Rhizobium trifolii and R. lupini in a sterilized infertile sandy soil were studied at different temperatures. R. trifolii grew at a faster rate than R. lupini at all temperatures up to 30°C. The optimum temperature for growth for both species was found to be approximately 30°. Temperatures higher than 35° were found to be lethal for both species, the cells of R. trifolii being the more sensitive. In a fertile sandy loam the growth rates of both species were improved, the effect being more pronounced with R. lupini. The presence of the appropriate host plants in the sterilized infertile sand resulted in faster growth rates in both species, particularly R. lupini.

GROWTH CHARACTERISTICS AND COMPETITIVE PARAMETERS OF MICROCYSTIS AERUGINOSA AND SCENDESMUS QUADRICAUDA AT DIFFERENT TEMPERATURES

2009 ◽  
Vol 32 (5) ◽  
pp. 720-727 ◽  
Author(s):  
Zhong-Ming ZHENG ◽  
Pei-Feng BAI ◽  
Kai-Hong LU ◽  
Chun-Hua JIN ◽  
Liang ZHANG
Keyword(s):  
Microcystis Aeruginosa ◽  
Growth Characteristics ◽  
Different Temperatures

scholarly journals Growth Modeling Kinetics of Aspergillus flavus in Dried Jujube at Different Temperatures

2021 ◽  
Author(s):  
Yiming Guo ◽  
Hua Ji
Keyword(s):  
Growth Rate ◽  
Growth Kinetic ◽  
Lag Time ◽  
Growth Characteristics ◽  
Optimal Temperature ◽  
Different Temperatures ◽  
Lag Period ◽  
Storage Methods ◽  
Kinetics Of

Dried jujube is a characteristic fruit of Xinjiang. Aspergillus is one of the main pathogens that causes mold on dried jujube, and A. flavus is a toxin-producing species, the aflatoxin produced by A. flavus is extremely toxic and carcinogenic. In this study, the growth kinetic models of A. flavus isolated from red jujube at different temperatures and times were fitted to Huang model and linear equation respectively, the Cardinal model was used to describe the growth rate and lag time of A. flavus on dried jujube agar. It turned out that 30–35 °C was the optimal temperature for growing A. flavus, so dried jujube should avoid storing in this temperature range. The kinetic model established in this study will help to understand the growth characteristics of A. flavus, and lay a foundation for evaluating the quality of stored dried jujube and predictions of shelf life, which are conducive to optimizing storage methods for dried jujube. It can be judged according to the value of Af and Bf, the Huang model had a better fitting effect than the Baranyi model, The two models all had the highest growth rate at 35 °C, and A. flavus grew more vigorously and the lag period shortened as the temperature was increased. The secondary Cardinal model had a good fitting effect on the growth rate and lag time, and the secondary Ratkowsky model had a good fitting effect on the growth rate. This study may have theoretical and application value to strengthen the safety of jujube storage in the future.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

1989 ◽  
Vol 47 ◽  
pp. 450-451
Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Surface Defects ◽  
Pure Metal ◽  
Device Fabrication ◽  
Native Oxide ◽  
Metal Thin Films ◽  
Recent Developments ◽  
Different Temperatures ◽  
Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

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