Chromosome doubling in a Rosa rugosa Thunb. hybrid by exposure of in vitro nodes to oryzalin: the effects of node length, oryzalin concentration and exposure time

2007 ◽  
Vol 26 (11) ◽  
pp. 1977-1984 ◽  
Author(s):  
J. F. Allum ◽  
D. H. Bringloe ◽  
A. V. Roberts
Keyword(s):  
Exposure Time ◽  
Chromosome Doubling ◽  
Rosa Rugosa

scholarly journals Optimization of the Colchicine Dropper Technique for Use in Vitro with Fragaria vesca

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 856C-856
Author(s):  
Bob Bors ◽  
J. Alan Sullivan
Keyword(s):  
Exposure Time ◽  
Chromosome Doubling ◽  
Initial Study ◽  
Fragaria Vesca ◽  
In Vitro Germination ◽  
True Leaf ◽  
Cotyledon Stage ◽  
Upward Growth ◽  
Growth Of Seedlings

Previous research has optimized the colchicine dropper technique for chromosome doubling under greenhouse conditions. In recent years, in vitro germination of cut strawberry achenes has greatly increased germination rates. Combining the two techniques would be especially useful when chromosome doubling is desired for interspecific hybridization. Fragaria vesca was chosen for initial study. Treatments included colchicine levels of 0%, 1%, 2%, 3%, 4%, or 5% (w/v); exposure time to colchicine was from 6 to 16 to 26 hours; application was at the cotyledon stage or after the first true leaf formed; presence or absence of 3 g activated charcoal/liter; and presence or absence of DMSO. Media consisted of MS salts and vitamins, 30 g sucrose/liter, and 2.5 g phytogel/liter. Charcoal enhanced upward growth of seedlings, thus allowing better placement of colchicine droplets. Reduced exposure time and application at the first true-leaf stage allowed higher levels of colchicine to be used without greatly reducing the vigor of treated seedlings.

Methods of experimental polyploidization and their use in apple breeding

2020 ◽  
Vol 62 ◽  
pp. 85-90
Author(s):  
L. V. Tashmatova ◽  
O. V. Matsneva ◽  
T. M. Khromova ◽  
V. V. Shakhov
Keyword(s):  
Exposure Time ◽  
Cell Walls ◽  
Prolonged Exposure ◽  
Ornamental Plants ◽  
Colchicine Treatment ◽  
Apple Trees ◽  
Open Ground ◽  
High Concentrations ◽  
Diploid Gametes

The article presents methods of experimental polyploidy of fruit, berry and ornamental plants. The purpose of this review is to highlight the problems and prospects of polyploidization of plants in the open ground and in vitro culture and the possibility of their application for apple trees. For the purpose of obtaining apple tetraploids as donors of diploid gametes, seed seedlings were treated with a solution of colchicine in concentrations of 0.1-0.4 % for 24 and 48 hours. Colchicine concentrations of 0.3 % and 0.4 % at 48 hours of treatment had a detrimental eff ect on their development. As a result, tetraploids and chimeras were obtained from seeds from free pollination of the varieties Orlik, Svezhest, Kandil Orlovsky, as well as from seeds obtained from crossing the varieties Svezhest×Bolotovskoe, Moskovskoe Оzherel’e×Imrus, Girlyanda×Venyaminovskoe. The optimal concentration of colchicine was 0.1 %. Methods of colchicine treatment have been studied: 1) adding to the nutrient medium, colchicine concentration: 0.01%, 0.02%, exposure time 24h-19 days; 2) applying amitotic solution to the growth point, colchicine concentration: 0.1 %, 0.2 %, exposure time 24h-7 days. To increase the penetration of colchicine through the cell walls, a 0.1 % dimexide solution was used. Studies have shown that high concentrations and prolonged exposure to colchicine reduce the viability of explants.

scholarly journals 1222. Are Reduced Concentrations of Chlorine-Based Disinfectants Effective Against Candida auris?

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S439-S439
Author(s):  
Jessica Kumar ◽  
Jennifer Cadnum ◽  
Y Karen Ng Wong ◽  
Thriveen Sankar Chittoor Mana ◽  
Heba Alhmidi ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Exposure Time ◽  
Environmental Protection Agency ◽  
Simulated Patient ◽  
Patient Room ◽  
Candida Auris ◽  
Colony Forming Units ◽  
Sodium Dichloroisocyanurate

Abstract Background Currently, sporicidal disinfectants such as bleach are recommended for daily and terminal disinfection of the rooms of patients with Candida auris colonization and/or infection. However, bleach and other chlorine-based disinfectants can have adverse effects on surfaces and personnel. Disinfectant solutions with reduced chlorine concentrations are commonly used for other pathogens, but it is not known if diluted or alternative products maintain efficacy against C. auris both in vitro and in vivo. Methods We tested the efficacy of different concentrations of a sodium dichloroisocyanurate (NaDCC) product and sodium hypochlorite using the method recommended by the Environmental Protection Agency (EPA) for evaluation of the efficacy of liquid disinfectants against C. auris (EPA MLB SOP MB-35-00) and in a simulated patient room. Carriers were exposed to each disinfectant for 1 and 2 minutes. Log reductions were calculated by subtracting viable organisms recovered after disinfectant exposure vs. deionized water controls. Results As shown in the figure, the NaDCC product at 4306 ppm tested with a 2 minute contact time reduced C. auris by ≥5 log10 colony-forming units (CFU) but had reduced efficacy with shorter exposure time or lower concentrations. Sodium hypochlorite was effective with 1 or 2 minute exposure times at a concentration of 6,500 ppm, and was effective at 4,000 ppm with an exposure time of 2 minutes. In the simulated patient room, NaDCC reduced C. auris contamination by ≥6 log10 CFUs on all surfaces. Conclusion A chlorine-based NaDCC product was effective at reducing C. auris. Both NaDCC and sodium hypochlorite products exhibited reduced efficacy at lower concentrations, particularly at concentrations below 4000 ppm. The NaDCC products were also effective in reducing contamination in the simulated patient room. UV-C treatment was an effective adjunct to manual cleaning. Disclosures All authors: No reported disclosures.

scholarly journals Effect of blue laser on viability of Proteus mirabilis

2021 ◽  
pp. 1438-1446
Author(s):  
Mawada M. Funjan
Keyword(s):  
Exposure Time ◽  
Proteus Mirabilis ◽  
Bacterial Species ◽  
Test System ◽  
Blue Laser ◽  
Diffusion Method ◽  
Biochemical Tests ◽  
Burn Wounds ◽  
Antibiotic Susceptibility Test

The usage of blue laser has been considered as a therapeutic approach to prohibit the viability of bacterial species, but there is no agreement about optimum parameters to be used. The aim of this project is to study the influence of blue laser (450 nm) on the viability of the gram-negative bacteria  Proteus mirabilis isolated from burn wounds, using different exposure times (i.e. doses) in vitro. Seventy swab samples were collected from burn wounds of patients admitted to the burns unit in AL-Yarmouk teaching hospital in Baghdad, during the period from June to August 2019. The Bacteria were isolated and identified depending on their culture characteristics, biochemical tests, gram staining, and morphology, being finally confirmed by API 20E Test System. By using the disk diffusion method, susceptibility of the isolates to 12 different antibiotics was examined. One isolate of P. mirabilis was elected according to susceptibility to all antibiotics used.  To prepare bacterial solution, P. mirabilis was mixed with normal saline solution. Dilution of 10-6 cell/ml for p. mirabilis was selected from other serial dilutions. A number of colonies and colony forming units (CFUs/ml) were achieved and correlated to controls.  P. mirabilis was irradiated by blue diode laser (450 nm, 500mw) and exposed to different doses (24, 48, 72, 96, 120J/cm2) corresponding to respective exposure times (4, 8,12,16,20 minutes). The results of antibiotic susceptibility test indicate that the entire isolates of P. mirabilis were multidrug resistant. With the increase in laser dose (exposure times), the number of colonies and  CFUs/ml were reduced, reaching a highest inhibition in CFU/ml  at exposure time of  20 minutes, i.e. a dose of 120J/cm2 , with  irradiance of 0.1 watt/ cm2. No significant reduction was recorded in CFU/ml   at exposure time of 4 min (a dose of 24J/cm2). As a conclusion, the blue laser irradiation at wavelength of 450 nm and 500mw had antibacterial effects on P. mirabilis isolated from burn wounds with irradiance of 0.1watt/cm2 in vitro, as evidenced by the effective reduction in the viability of bacteria at a dose of 120J/cm2 corresponding to exposure time of 20 minutes.

scholarly journals In vitro Induced Mitotic Polyploidy in Drosera capensis L.

2013 ◽  
Vol 46 (4) ◽  
pp. 107-110 ◽  
Author(s):  
Pavla Zahumenicka ◽  
Barbora Sysova ◽  
Ales Holik ◽  
Eloy C. Fernandez
Keyword(s):  
Flow Cytometry ◽  
Survival Rate ◽  
Exposure Time ◽  
Leaf Segments

Abstract The objective of this study was to induce mitotic polyploidization in Drosera capensis. Tetraploid plants of D. capensis were induced successfully by treating leaf segments in vitro with oryzalin solution with four different concentrations (20, 40, 60 or 80 μM) for 12, 24 or 48 hours. Three tetraploid (2n = 4x = 80) plants were obtained in three treatments (20 μM for 48 h, 60 μM for 24 h and 80 μM for 12 h). Tetraploidy was confirmed by flow cytometry. The survival rate of these plants was not significantly influenced by oryzalin concentration or exposure time.

scholarly journals Virucidal Effect of Cold Atmospheric Gaseous Plasma on Feline Calicivirus, a Surrogate for Human Norovirus

2015 ◽  
Vol 81 (11) ◽  
pp. 3612-3622 ◽  
Author(s):  
Hamada A. Aboubakr ◽  
Paul Williams ◽  
Urvashi Gangal ◽  
Mohammed M. Youssef ◽  
Sobhy A. A. El-Sohaimy ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Exposure Time ◽  
Virus Titer ◽  
Feline Calicivirus ◽  
Virucidal Activity ◽  
Human Norovirus ◽  
Gaseous Plasma ◽  
Virucidal Effect ◽  
Unit Reduction

ABSTRACTMinimal food-processing methods are not effective against foodborne viruses, such as human norovirus (NV). It is important, therefore, to explore novel nonthermal technologies for decontamination of foods eaten fresh, minimally processed and ready-to-eat foods, and food contact surfaces. We studied thein vitrovirucidal activity of cold atmospheric gaseous plasma (CGP) against feline calicivirus (FCV), a surrogate of NV. Factors affecting the virucidal activity of CGP (a so-called radio frequency atmospheric pressure plasma jet) were the plasma generation power, the exposure time and distance, the plasma feed gas mixture, and the virus suspension medium. Exposure to 2.5-W argon (Ar) plasma caused a 5.55 log10unit reduction in the FCV titer within 120 s. The reduction in the virus titer increased with increasing exposure time and decreasing exposure distance. Of the four plasma gas mixtures studied (Ar, Ar plus 1% O2, Ar plus 1% dry air, and Ar plus 0.27% water), Ar plus 1% O2plasma treatment had the highest virucidal effect: more than 6.0 log10units of the virus after 15 s of exposure. The lowest virus reduction was observed with Ar plus 0.27% water plasma treatment (5 log10unit reduction after 120 s). The highest reduction in titer was observed when the virus was suspended in distilled water. Changes in temperature and pH and formation of H2O2were not responsible for the virucidal effect of plasma. The oxidation of viral capsid proteins by plasma-produced reactive oxygen and nitrogen species in the solution was thought to be responsible for the virucidal effect. In conclusion, CGP exhibits virucidal activityin vitroand has the potential to combat viral contamination in foods and on food preparation surfaces.

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