scholarly journals THE EFFECTS ON BIOLOGICAL MATERIALS OF FREEZING AND DRYING BY VACUUM SUBLIMATION

1954 ◽  
Vol 100 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Donald Greiff ◽  
Henry Pinkerton
Keyword(s):  
Influenza Virus ◽  
Biological Materials ◽  
Continuous Operation ◽  
Virus Suspension ◽  
Vacuum Sublimation ◽  
End Point ◽  
Different Temperatures ◽  
Time Required

A vacuum sublimation apparatus is described which will permit, (a) the removal of water from virus suspensions at temperatures ranging down to –80°C., (b) continuous operation with a minimum of attention from the investigator, (c) sealing off of samples at operating pressures (10–5 mm. Hg), (d) simultaneous lyophilization of aliquot samples at different temperatures, (e) isolation of a portion of the apparatus without disturbing the remainder of the system, and (f) determination of the end-point of sublimation without disturbing the samples. The time required for drying 0.1 ml. of influenza virus suspension was shown to increase markedly with decrease of temperature, 8 days being required for dehydration at –80°C. in contrast to 2 days at –30°C. and 1 day at 0°C.

scholarly journals The mechanism of ciliary movement. III.—The effect of temperature

1923 ◽  
Vol 95 (664) ◽  
pp. 6-15 ◽  
Keyword(s):  
Fine Particles ◽  
Effect Of Temperature ◽  
General Effect ◽  
Ciliary Movement ◽  
Small Glass ◽  
Satisfactory Method ◽  
Different Temperatures ◽  
Time Required ◽  
Rate Of Movement

The general effect of temperature on the rate of ciliary movement has been known for many years. In 1858, Calliburcés(1) determined the rate of movement of the cilia on the frog’s œsophagus, by observing the speed of rotation of a small glass cylinder laid in contact with the ciliated surface; he found that an increase in temperature caused a marked increase in the speed of rotation. Similar results, obtained by various methods, were recorded by Roth (11), Engelmann (2), and Rossbach (10), but in no case were the observations sufficient for quantitative analysis. Owing to the fact that ciliated surfaces are liable to be contaminated by strands of mucus, data based on the speed imparted by the cilia to a revolving drum are liable to considerable experimental error; this error is also increased by the mechanical friction involved by such instruments. The only satisfactory method of estimating the speed of the cilia on the gills of Mytilus appears to be by a determination of the rate of transportation of fine particles over the surface of the tissue; such particles can be watched under the low power of the microscope, and any irregularities due to the presence of mucus can be detected.The method adopted in the following experiments was to determine the time required to move at a uniform rate a very small circular plate of platinum over a distance of 1 cm. The tissue was fixed by glass weights to the bottom of a small glass dish, across the base of which were marked two lines 1 cm. apart. The relative speed at different temperatures was recorded, using the speed at 15° as an arbitrary unit of 100.

scholarly journals A METHOD FOR THE QUANTITATIVE DETERMINATION OF BACTERIOPHAGE

1930 ◽  
Vol 13 (5) ◽  
pp. 557-564 ◽  
Author(s):  
Albert P. Krueger
Keyword(s):  
Quantitative Determination ◽  
Quantitative Estimation ◽  
Quantitative Relationship ◽  
End Point ◽  
Time Required

1. In the case of the staphylococcus and antistaphylococcus phage studied, with the total volume of the mixture being kept constant, there exists a definite quantitative relationship between CPhage and the time required to reduce a particular concentration of growing phage-susceptible bacteria to an arbitrary turbidity end-point. 2. This relationship furnishes a basis for the quantitative estimation of bacteriophage. A method is described having an accuracy within ±5 per cent.

Enhanced information from biological materials through technological improvements in cryo-electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 788-789
Author(s):  
Marc J.C. de Jong ◽  
Wim M. Busing ◽  
Max T. Otten
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Biological Materials ◽  
Electron Crystallography ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
The Many ◽  
Technological Improvements ◽  
Beam Damage

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.

Quantitative Assessment of Soluble Fibrin in Plasma by Affinity Chromatography – A Comparative Study with desAA-Fibrin, desAABB-Fibrin and Fibrinogen

1985 ◽  
Vol 54 (02) ◽  
pp. 533-538 ◽  
Author(s):  
Wilfried Thiel ◽  
Ulrich Delvos ◽  
Gert Müller-Berghaus
Keyword(s):  
Affinity Chromatography ◽  
Calcium Ions ◽  
Quantitative Assessment ◽  
Fluid Phase ◽  
Soluble Fibrin ◽  
Binding Characteristics ◽  
Different Temperatures ◽  
Immobilized Proteins ◽  
Sepharose 4B

SummaryA quantitative determination of soluble fibrin in plasma was carried out by affinity chromatography. For this purpose, desAA-fibrin and fibrinogen immobilized on Sepharose 4B were used at the stationary side whereas batroxobin-induced 125I-desAA-fibrin or thrombin-induced 125I-desAABB-fibrin mixed with plasma containing 131I-fibrinogen represented the fluid phase. The binding characteristics of these mixtures to the immobilized proteins were compared at 20° C and 37° C. Complete binding of both types of fibrin to the immobilized desAA-fibrin was always seen at 20° C as well as at 37° C. However, binding of soluble fibrin was accompanied by substantial binding of fibrinogen that was more pronounced at 20° C. Striking differences depending on the temperature at which the affinity chromatography was carried out, were documented for the fibrinogen-fibrin interaction. At 20° C more than 90% of the applied desAA-fibrin was bound to the immobilized fibrinogen whereas at 37° C only a mean of 17% were retained at the fibrinogen-Sepharose column. An opposite finding with regard to the tested temperature was made with the desAABB-fibrin. Nearly complete binding to insolubilized fibrinogen was found at 37° C (95%) but only 58% of the desAABB-fibrin were bound at 20° C. The binding patterns did not change when the experiments were performed in the presence of calcium ions. The opposite behaviour of the two types of soluble fibrin to immobilized fibrinogen at the different temperatures, together with the substantial binding of fibrinogen in the presence of soluble fibrin to insolubilized fibrin in every setting tested, devaluates affinity chromatography as a tool in the quantitative assessment of soluble fibrin in patients’ plasma.

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