scholarly journals A critical intracellular concentration of fully reduced non-methylated folate polyglutamates prevents macrocytosis and diminished growth rate of human cell line K562 in culture

1983 ◽  
Vol 214 (2) ◽  
pp. 465-470 ◽  
Author(s):  
D Watkins ◽  
B A Cooper
Keyword(s):  
Growth Rate ◽  
Cell Line ◽  
Culture Medium ◽  
K562 Cells ◽  
Optimal Growth ◽  
Human Cell Line ◽  
Intracellular Concentration ◽  
Folate Concentration ◽  
Rate Of Growth ◽  
Optimal Growth Rate

Growth rate of human leukaemic cell line K562 was independent of intracellular folate concentration when this was greater than 1.5 microM. When intracellular folate concentration was less than 1.5 microM, the rate of growth was proportional to the logarithm of intracellular concentration of non-methylated fully reduced folates, but not to the logarithm of the intracellular concentration of N5-methyltetrahydropteroylglutamate. Intracellular folate concentration sufficient to support an optimal growth rate was maintained by either DL-N5-formyltetrahydropteroylglutamate or DL-N5-methyltetrahydropteroylglutamate at a 100-fold lower concentration than pteroylglutamate. Addition of hypoxanthine to culture medium partially restored growth of folate-depleted cells: thymidine had no effect on growth rate either alone or in combination with thymidine. Folate-depleted cells with diminished growth rate were larger than replete cells, but did not have megaloblastic morphology. The mitotic index was not decreased in cultures with diminished growth rate. The rate of growth and cell size of K562 cells is thus dependent on a critical intracellular concentration of non-methylated tetrahydrofolates, which may be maintained by different concentrations of either reduced folates or pteroylglutamate.

scholarly journals Improvement of K562 Cell Line Transduction by FBS Mediated Attachment to the Cell Culture Plate

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Maryam Abbasalipour ◽  
Mohammad Ali Khosravi ◽  
Sirous Zeinali ◽  
Hossein Khanahmad ◽  
Morteza Karimipoor ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Line ◽  
K562 Cells ◽  
Human Cell Line ◽  
Transduction Efficiency ◽  
Simple Method ◽  
Clinical Phase ◽  
Gene Insertion ◽  
Coated Plate ◽  
Fetal Bovine

Lentiviral vectors have been used for gene therapy in the clinical phase in recent years. These vectors provide a tool for gene insertion, deletion, or modification in organisms. The K562 human cell line has been used extensively in hematopoietic research. Despite its broad application, it is hard-to-transfection and transduction. So, this study presents a simple method to increase the transduction efficiency of K562 cells with a low multiplicity of infection (MOI) of the virus particle. For this purpose, 24-well plate was coated by 300μl fetal bovine serum (FBS) before seeding. Then 2×104K562 cells were seeded in each FBS coated plate. After 24h, K562 cells were attached and doubled. Different amount of lentivirus-based GFP vector according to MOI (5, 10, 15, and 20) along with 8μg polybrene was added to the attached K562 cells and after 6h cells and viral particle complex were spinfected. Then cells were returned to the plate and incubated in 37°C overnight. After 48h transduction efficiency was established by measuring the GFP-expressing cells by flow cytometry. Flow cytometry analysis showed that, after plate treatment by FBS, 64.5% transduction rate in K562 cells was achieved at MOI=20. Therefore, this method can be an effective and simple way to increase the lentiviral transduction rate for suspended cells such as K562.

Comment: The Optimal Growth Rate of Money

1968 ◽  
Vol 76 (4, Part 2) ◽  
pp. 876-880 ◽  
Author(s):  
Robert W. Clower
Keyword(s):  
Growth Rate ◽  
Optimal Growth ◽  
Optimal Growth Rate

scholarly journals Characterization of Colletotrichum acutatum Isolates Causing Anthracnose of Almond and Peach in California

1997 ◽  
Vol 87 (9) ◽  
pp. 979-987 ◽  
Author(s):  
J. E. Adaskaveg ◽  
R. J. Hartin
Keyword(s):  
Growth Rate ◽  
South Carolina ◽  
Dna Sequences ◽  
Optimal Growth ◽  
Colletotrichum Acutatum ◽  
Similar Response ◽  
Mature Fruit ◽  
Causal Organism ◽  
Conidial Morphology ◽  
Optimal Growth Rate

The causal organism responsible for the recent outbreak of almond and peach anthracnose in California was identified and characterized as Colletotrichum acutatum. Isolates of C. acutatum from almond were found to be similar to California strawberry isolates and South Carolina peach and apple isolates of C. acutatum based on conidial morphology, temperature relationships, fungicide sensitivity, and polymerase chain reaction (PCR) methods using DNA species-specific primers. On almond, blossoms and immature or mature fruit were affected by the disease, causing direct losses of crop. On peach, the disease was observed only on mature fruit. Pathogenicity of almond and peach isolates of C. acutatum was demonstrated on wound- and nonwound-inoculated almond or peach fruit by fulfilling Koch's postulates. Conidial morphology of isolates was variable, depending on the medium or substrate used to culture the isolates. Isolates of C. acutatum from strawberry, almond, and peach were grouped together based on a similar response to temperature, with an optimal growth rate at 25°C (generally less than 10 mm/day), whereas isolates of C. gloeosporioides from citrus and papaya had an optimal growth rate at 30°C (generally greater than 10 mm/day). In fungicide disk assays, isolates of C. acutatum from strawberry, peach, and apple, as well as almond and peach isolates from California, were less sensitive to benomyl at 300, 600, or 1,200 μg/ml. In contrast, C. gloeosporioides isolates from citrus and papaya were very sensitive to benomyl at all concentrations evaluated. All isolates of both species were sensitive to captan (300, 600, or 1,200 μg/ml). Oligonucleotide primers were synthesized for C. acutatum, C. fragariae, or C. gloeosporioides using published DNA sequences from the internal transcribed spacer 1 region of ribosomal DNA. Thirty-two Colletotrichum isolates from almond fruit produced DNA products with a C. acutatum primer (CaInt-2) that matched products and approximate molecular weight of known C. acutatum isolates. No PCR products were produced with primers for C. gloeosporioides or C. fragariae. Isolates from citrus and papaya produced DNA products only with primers from C. gloeosporioides or C. fragariae. Thus, worldwide, anthracnose of almonds may be caused by either C. gloeosporioides, as previously reported, or by C. acutatum, as indicated in this study.

Linear Stability Analysis in a Compressible Axisymmetric Swirling Jet

2014 ◽  
Vol 574 ◽  
pp. 15-20
Author(s):  
Zhi Wei Guo ◽  
Si Min Shen ◽  
Wei Min Feng ◽  
Bo Fu Wang
Keyword(s):  
Growth Rate ◽  
Stability Analysis ◽  
Linear Stability ◽  
Previous Analysis ◽  
Optimal Growth ◽  
Flow Dynamics ◽  
Swirl Number ◽  
Swirling Jet ◽  
Optimal Growth Rate ◽  
The Stability

Temporal linear stability of a compressible axisymmetric swirling jet is investigated. The present work extends a previous analysis to include the effects of swirl number on the stability of flow dynamics. Results obtained show that the optimal growth rate of disturbance for azimuthal wavenumber n = -1 is larger than that for n = -2 while the corresponding frequencies for both n increases as axial wavenumber increases. As swirl number q increases, the optimal growth rate of disturbance also increases. What is more, there is an optimal swirl number for small axial wavenumbers, which is different from the situation for medium and large axial wavenumbers.

The effect of copper sulphate on the growth of the alga Chlorella

1977 ◽  
Vol 66 (03) ◽  
pp. 169-177 ◽  
Author(s):  
Victor A. Moss ◽  
J. Alan Roberts ◽  
H. Keith ◽  
L. Simpson
Keyword(s):  
Growth Rate ◽  
Copper Sulphate ◽  
Culture Medium ◽  
Rate Of Growth ◽  
General Growth ◽  
Growth Stimulant ◽  
Effect Of Copper ◽  
Fresh Culture Medium ◽  
Fresh Culture

Summary• The actions of dilutions and potencies of copper sulphate on the growth of Chlorella were studied in order to determine whether a potency of copper sulphate was beneficial to a culture of Chlorella which had been poisoned by copper sulphate.• The growth rate of Chlorella in Chu 10 culture medium was greatly reduced by a concentration of copper sulphate of 10−5 Molar (M). Algae grown in Moyse culture medium, which contain 3·2×10−7 M copper sulphate, were less sensitive to copper sulphate. Chlorella whose growth had been inhibited by copper sulphate was, when resuspended in fresh culture medium, more sensitive to further added copper sulphate than normal algae.• Potencies of copper sulphate prepared in the laboratory, in the concentration range 4c (4×10−8 M) to 15c had no effect on the growth of either normal or poisoned algae.• Several batches of a 15c potency prepared by A. Nelson & Co., Ltd. increased the rate of growth of both unpoisoned and poisoned algae. These results are attributed to the fact that the batches of potency contained a general growth stimulant, rather than to a stimulatory homœopathic action of the potency itself which would have affected the poisoned algae only.

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