Facilitating protein denaturation in organic solvent and the contribution to the promoting dispersion of graphite nanoplatelets in a polymer

The activity of biocatalysts in nonaqueous solvents is related to the interaction of organic solvents with cells or enzymes. The behavior of proteins is strongly dependent on the protonation state of their ionizable groups, which ionization constants are greatly affected by the solvent. Due to the weak ionizing and dissociating powers of common organic solvents, the charge of the protein will change significantly when the protein is transferred from water to common organic solvents, resulting in protein denaturation. In this work, glycerol carbonate (GC) was synthesized, which ionizing and dissociating abilities were very close to those of water. Transesterification activities ofCandida antarcticalipase B (CALB) in GC were comparable to those in water and remained constant during 4-week storage.Bacillus subtilisandSaccharomyecs cerevisiaewere cultured in liquid media containing GC with test tubes. In the medium containing low GC concentration,Bacillus subtilisandSaccharomyecs cerevisiaegrew well as in a medium containing no organic solvent, but, in the medium containing high GC concentration, the growth ofBacillus subtilisandSaccharomyecs cerevisiaewas suppressed. The results suggested that GC is a potential biosolvent, which has great significance to biocatalysis in nonaqueous solvents.

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Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081097 ◽

1978 ◽

Vol 36 (2) ◽

pp. 46-47

Author(s):

Jan Zarzycki ◽

Joseph Szroeder

Keyword(s):

Mammary Gland ◽

Protein Denaturation ◽

Chemical Constituents ◽

Freeze Substitution ◽

Electron Microscopic Examination ◽

Mouse Mammary Gland ◽

Electron Microscopic ◽

Preparation Methods ◽

Microscopic Studies ◽

Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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A Study of the Ultrastructure of Visual Cell Outer Segment Membranes, Using a Water-Miscible Embedding Medium and Differential Staining

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009350x ◽

1972 ◽

Vol 30 ◽

pp. 50-51

Author(s):

Anthony J. Godfrey

Keyword(s):

Outer Segment ◽

Protein Denaturation ◽

Uranyl Acetate ◽

Differential Staining ◽

Visual Cell ◽

Lead Citrate ◽

Chick Retina ◽

Dark Staining ◽

Embedding Medium ◽

The Individual

Aldehyde-fixed chick retina was embedded in a water-containing resin of glutaraldehyde and urea, without dehydration. The loss of lipids and other soluble tissue components, which is severe in routine methods involving dehydration, was thereby minimized. Osmium tetroxide post-fixation was not used, lessening the amount of protein denaturation which occurred. Ultrathin sections were stained with 1, uranyl acetate and lead citrate, 2, silicotungstic acid, or 3, osmium vapor, prior to electron microscope examination of visual cell outer segment ultrastructure, at magnifications up to 800,000.Sections stained with uranyl acetate and lead citrate (Fig. 1) showed that the individual disc membranes consisted of a central lipid core about 78Å thick in which dark-staining 40Å masses appeared to be embedded from either side.

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144. Thermodynamics of the Adsorption of Organic Solvent Vapor from Humidified Air

10.3320/1.2762977 ◽

1999 ◽

Author(s):

D.W. Underhill ◽

K. Kawar

Keyword(s):

Organic Solvent ◽

Solvent Vapor ◽

Humidified Air

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STUDIES ON A NON-MELATONIN PINEAL ANTI-GONADOTROPHIN

Acta Endocrinologica ◽

10.1530/acta.0.0690257 ◽

1972 ◽

Vol 69 (2) ◽

pp. 257-266 ◽

Cited By ~ 38

Author(s):

Bryant Benson ◽

Mary Jane Matthews ◽

Alvin E. Rodin

Keyword(s):

Solvent Extraction ◽

Organic Solvent ◽

Pineal Gland ◽

Gel Filtration ◽

Test System ◽

Pineal Body ◽

Physiological Effects ◽

Organic Solvent Extraction ◽

Gland Function

ABSTRACT Continuing investigation of pineal gland function indicates that the anti-gonadotrophic activity of this organ cannot be attributed solely to the postulated hormone melatonin, the concentration of which is negligible in the pineal body compared to quantities required to produce unequivocal physiological effects. A non-melatonin antigonadotrophic substance recently isolated from bovine pineal glands was further purified by organic solvent extraction, ultrafiltration and gel filtration. Studies of partial blockage of compensatory ovarian hypertrophy in unilaterally ovariectomized Charles River CD-1 mice indicated that this substance is significantly more potent than melatonin in this test system.

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