The effect of drying on Spirodela polyrhiza turion germination

1981 ◽  
Vol 59 (1) ◽  
pp. 104-105 ◽  
Author(s):  
Lada Malek

Mild drying in air or exposure to the osmoticum polyethylene glycol 6000 at 5, 10, or 20% (w/w) concentration stimulated germination rate of Spirodela polyrhiza (duckweed) turions. Treatment of the turions for several days in polyethylene glycol 6000 induced rapid germination of the turions. This germination response provides a model system for the study of metabolic changes prior to and during turion germination.


2020 ◽  
Vol 13 (5) ◽  
pp. 18
Author(s):  
A. M. S. Oliveira ◽  
A. A. Silva ◽  
M. C. Vasconcelos ◽  
J. A. A. Granja ◽  
J. M. R. Faria ◽  
...  

Physiological conditioning is a technique that consists in controlling the speed of water uptake by seeds, with osmotic solutions, aiming to improve their quality, reducing time and increasing germination rate. Eremanthus erythropappus (D.C.) MacLeish seeds were subjected to priming with polyethylene glycol 6000 (PEG), potassium nitrate (KNO3) and the combination of the two at the concentrations of 0.4; -0.8; -1.0; -1.2 and -1.4 MPa for four, six and eight days. Germination, germination speed index (GSI), emergence, emergence speed index (ESI) and expression of superoxide dismutase (SOD), catalase (CAT) and peroxidase (PO) enzymes were assessed. E. erythropappus seed priming in polyethylene glycol solution with potentials between -0.8 MPa and -1.4 MPa is not satisfactory because it adversely affects germination and reduces the activity of peroxidase and catalase enzymes. The other substances were not significant so there is a need for further research with other substances and / or concentrations



2008 ◽  
pp. 133-138 ◽  
Author(s):  
Sanja Djakovic ◽  
Sanja Ilic ◽  
Jelena Cvejic ◽  
Milica Atanackovic ◽  
Mirjana Antov ◽  
...  

The objective of this study was the investigation of the extractive bioconversion of apigenin-7-O-?-glucoside in camomile ligulate flowers into apigenin by autofermentation in polyethylene glycol 6000/dextran 200000 two-phase system. In 22.5% polyethylene glycol/14% dextran aqueous two-phase system the obtained yield of apigenin in the top phase was 96.5%. In the presence of plant material that partiotioned to the interphase, the yield of apigenin in the top phase was 3.5 times higher in comparison to the model system.



1989 ◽  
Vol 21 (3) ◽  
pp. 255-258 ◽  
Author(s):  
Evangélos Biziagos ◽  
Jacques Passagot ◽  
Jean-Marc Crance ◽  
Robert Deloince

The concentration of cell-culture-adapted hepatitis A virus (HAV) from experimentally contaminated distilled, drinking, waste and seawater was performed by using a filter adsorption-elu-tion method in the following conditions: HAV seeded in water was adsorbed at pH 4.0 to two nitrocellulose membranes (1.2 and 0.45 µm porosity for distilled and tap water or 8.0 and 3.0 µm porosity for waste and seawater), then eluted by 3% beef-extract at pH 8.5 and further concentrated by polyethylene glycol 6000 precipitation. Thus, HAV in 5 to 50 liters of seeded waters was concentrated approximately 1,700 to 17,000 fold with greater than 70% recovery of the initial virus added to the samples.



1996 ◽  
Vol 121 (3) ◽  
pp. 423-429 ◽  
Author(s):  
Lewis W. Jett ◽  
Gregory E. Welbaum ◽  
Ronald D. Morse

Priming, a controlled-hydration treatment followed by redrying, improves the germination and emergence of seeds from many species. We compared osmotic and matric priming to determine which was the most effective treatment for improving broccoli seed germination and to gain a greater understanding of how seed vigor is enhanced by priming. Broccoli (Brassica oleracea L. var. italica) seeds were osmotically primed in polyethylene glycol (PEG 8000) at -1.1 MPa or matrically primed in a ratio of 1.0 g seed:0.8 g synthetic calcium silicate (Micro-Cel E):1.8 ml water at -1.2 MPa. In the laboratory, germination rates and root lengths were recorded from 5 to 42C and 10 to 35C, respectively. Broccoli seeds germinated poorly at >35C. Root growth after germination was more sensitive to temperatures >30C and <15C than radicle emergence. Matric and osmotic priming increased germination rate in the laboratory, greenhouse, and field. However, matric priming had a greater effect on germination and root growth rates from 15 to 30C. Neither priming treatment affected minimum or maximum germination or root growth temperatures. Both priming treatments decreased the mean thermal time for germination by >35%. The greater germination performance of matrically primed seeds was most likely the result of increased oxygen availability during priming, increased seed Ca content, or improved membrane integrity.



1986 ◽  
Vol 32 (6) ◽  
pp. 1020-1022 ◽  
Author(s):  
J A Viedma ◽  
A de la Iglesia ◽  
M Parera ◽  
M T López

Abstract This rapid, sensitive equilibrium turbidimetric immunoassay for quantification of alpha 1-antitrypsin involves a monospecific antibody, polyethylene glycol 6000 to accelerate and enhance the immunoprecipitation reaction, and Tween 20 surfactant to decrease and stabilize the sample-blank values. Turbidity at 334 nm is measured by an automated discrete analyzer. Grossly lipemic, icteric, or hemolyzed samples can be assayed. Correlation with results by radial immunodiffusion (RID) was excellent (r = 0.97, n = 84). Analytical recovery averaged 97.7 (SD 2.9)%. Within-run CVs ranged from 1.6 to 1.9%, between-day CVs from 2.0 to 3.5%. Reference values for healthy adults (n = 147) were determined by parametric estimation (for an assumed normal distribution of untransformed data). The lower limit (g/L) with its 0.90 confidence interval is 1.23 (range 1.18-1.28), the upper limit is 2.15 (2.10-2.20), and the mean is 1.69 g/L.



1995 ◽  
Vol 73 (1-2) ◽  
pp. 116-122 ◽  
Author(s):  
Aldo Milzani ◽  
Isabella DalleDonne ◽  
Roberto Colombo

We show that the modification of actin subdomain 1 by N-ethylmaleimide (NEM), which binds Cys-374 close to the C-terminus of the molecule, inhibits the α-actinin-induced bundling of actin filaments. This effect is not merely related to the block of Cys-374, since N-(1-pyrenyl)iodoacetamide (pyrene-IA) is unable to prevent bundling. Considering that NEM (but not pyrene-IA) influences actin assembly, we suggest that the inhibition of the actin – α-actinin interaction is due to the chemical modification of actin Cys-374 which, by inducing a marked spatial reorganization of actin monomers, is able to modify both the intra- and inter-molecular interactions of this protein. Finally, NEM-modified actin filaments form bundles in the presence of polyethylene glycol 6000 since, in this case, the side by side association of actin filaments does not depend on the accessibility of binding sites nor on the formation of chemical bonds.Key words: chemically modified actin, N-ethylmaleimide, pyrene-IA, Cys-374, actin bundles, α-actinin.



2008 ◽  
Vol 13 (4) ◽  
pp. 302-308 ◽  
Author(s):  
Zhiliang Jiang ◽  
Lili Wei ◽  
Mingjing Zou ◽  
Aihui Liang ◽  
Mianwu Meng

Nanogold, 8 nm in size, was used to label goat antihuman immunoglobulin M (GIgM) to obtain a new immunonanogold resonance scattering (RS) probe (Au-GIgG) for quantitation of trace immunoglobulin M (IgM). The Au-GIgG combined with IgM to form nanogold-labeled immunocomplex causes the RS intensity at 580 nm to be enhanced, in pH 4.49 KH2PO 4-Na2HPO4 buffer and in the presence of polyethylene glycol 6000. The enhanced RS intensity at 580 nm (ΔI580 nm) is proportional to the IgM concentration in the range of 1.5 to 2000 ng/mL, with a lower detection limit of 0.98 ng/mL. The immunonanogold RS assay was used to assay IgM in serum samples, with sensitivity, selectivity, and simplicity. ( Journal of Biomolecular Screening 2008:302-308)



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