scholarly journals THE CHEMICAL FRACTIONATION OF LYMPHATIC ORGANS

1956 ◽  
Vol 2 (5) ◽  
pp. 557-571
Author(s):  
Eugene L. Hess ◽  
Saima E. Lagg
Keyword(s):  
Electrophoretic Mobility ◽  
Physical Property ◽  
Dry Weight ◽  
Chemical Fractionation ◽  
Palatine Tonsils ◽  
Lymphatic Organs

A method for chemically fractionating lymphatic organs has been described. The method has been shown to be applicable to bovine palatine tonsils, sheep palatine tonsils, and bovine thymus. Approximately 50 per cent of the dry weight of tonsils and about 30 per cent of thymus has been found to be soluble in the 0.15 M NaCl extract. Four components have been isolated which together account for 65 per cent by weight of the material in the extracts. Four other components have been identified and partially defined by means of electrophoretic mobility, solubility, or some other chemical or physical property.

scholarly journals The Chemical Fractionation of Rabbit and Swine Thymus

1957 ◽  
Vol 3 (5) ◽  
pp. 812-815 ◽  
Author(s):  
Eugene L. Hess ◽  
Saima E. Lagg
Keyword(s):  
Small Mammal ◽  
Chemical Fractionation ◽  
Yield Data ◽  
Palatine Tonsils ◽  
Fractionation Procedure ◽  
Calf Thymus

A chemical fractionation procedure, previously found applicable to bovine thymus and bovine and ovine palatine tonsils, was used to fractionate rabbit and hog thymus. With respect to the chemical fractionation steps, yields of fractions, and optical and electrophoretic properties, extracts from hog and rabbit thymus were indistinguishable from similar extracts prepared from calf thymus. The study provides composition and yield data applicable to the thymus of a small mammal readily available in most laboratories.

scholarly journals Canopy Nutrient Allocation in Relation to Incident Light in the Tropical Fruit Tree Borojoa patinoi (Cuatr.)

1993 ◽  
Vol 118 (6) ◽  
pp. 777-785 ◽  
Author(s):  
Jonathan Lynch ◽  
Alonso González
Keyword(s):  
Incident Light ◽  
Dry Weight ◽  
Fruit Tree ◽  
Mineral Nutrient ◽  
Chemical Fractionation ◽  
Nutrient Allocation ◽  
Tropical Fruit ◽  
Local Branching ◽  
Unit Leaf ◽  
Leaf Dry Weight

The relationship of incident photosynthetically active radiation (PAR) and mineral nutrient allocation was evaluated in canopies of Borojoa patinoi (Cuatr.) growing in the Chocó rainforest of Colombia, South America. Allocation of P in the canopy was positively correlated with incident PAR, principally because of increased leaf frequency (number of leaves per unit volume of canopy) brought about by local branching, with a smaller contribution from increased specific leaf weight (SLW, leaf dry weight per unit leaf area). The chemical fractionation of P within leaves did not respond to incident PAR. Canopy N allocation also was positively correlated with incident PAR because of increased leaf frequency and SLW. The N partitioning to soluble protein rather than chlorophyll was positively correlated with incident PAR. The allocation of K, Ca, Mg, S, Mn, and Cu also was positively correlated with incident PAR primarily because of increased leaf frequency and secondarily because of increased SLW. The area of individual leaves and the concentration of nutrients in leaf dry weight were not important in determining nutrient allocation responses to incident PAR. Our observations suggest that leaf frequency caused by local branching, followed by changes in SLW, are the primary determinants of canopy nutrient allocation in this tropical fruit tree.

Distribution and chemical fractionation of arsenic in surficial sediments of the Lami coastal environment in Fiji

2010 ◽  
Vol 28 (1) ◽  
pp. 78 ◽  
Author(s):  
Vimlesh Chand ◽  
Surendra Prasad ◽  
Rajendra Prasad
Keyword(s):  
Graphite Furnace ◽  
Sediment Quality ◽  
Absorption Spectrometry ◽  
Dry Weight ◽  
Strong Acid ◽  
Coastal Environment ◽  
Chemical Fractionation ◽  
Quality Guidelines ◽  
Graphite Furnace Atomic Absorption ◽  
Metal Monitoring

A case of arsenic contamination has recently been detected in the Lami coastal environment during the course of a heavy metal monitoring in Fiji's coastal environment. Twenty two surficial sediment samples were sampled during the 2008–2009 period, extracted for arsenic and analysed using graphite furnace atomic absorption spectrometry. Two sites within the Lami estuary recorded the highest As levels of 334 and 282 mg kg–1 as dry weight in sediments samples, which has greatly exceeded the local and global average background concentrations. Chemical fractionation studies using a standard sequential protocol showed that As is mostly associated with residual (strong acid extractable) phase of the sediments, however significant amounts of As were also detected in bioavailable (exchangeable, water and acid soluble), reducible and oxidisable fractions. Comparison with standard sediment quality guidelines (SQGs) indicate that As levels are likely to be highly toxic to biota, hence further ecotoxicological studies are warranted to evaluate possible environmental effects on the aquatic environment.

scholarly journals SOME PROPERTIES OF PURIFIED PROTHROMBIN AND ITS ACTIVATION WITH SODIUM CITRATE

Blood ◽  
1950 ◽  
Vol 5 (5) ◽  
pp. 421-433 ◽  
Author(s):  
WALTER H. SEEGERS ◽  
ROBERT I. MCCLAUGHRY ◽  
JOHN L. FAHEY
Keyword(s):  
Ammonium Sulfate ◽  
Electrophoretic Mobility ◽  
Sodium Citrate ◽  
Specific Activity ◽  
Dry Weight ◽  
Potassium Citrate ◽  
Potassium Oxalate ◽  
Concentrated Solutions ◽  
Thrombin Activity ◽  
Prothrombin Activation

Abstract Prothrombin preparations were examined by electrophoresis and found to contain approximately 90 per cent of the protein in one component. Such products possess a specific activity of 1,400 units per milligram of dry weight when analyzed with reagents and technics that give a value of 32.9 ± 30 units of prothrombin per cc. of oxalated bovine plasma. The electrophoretic mobility is approximately equivalent to that of α1-globulin. That of thrombin is less. The isoelectric point in 0.1 ionic strength salt solution is near pH 4.2, and for thrombin it is approximately pH 4.8. Analysis of dry preparations indicated 0.96 per cent sulfur, 13.57 per cent nitrogen, 4.58 per cent tyrosine, and 3.33 per cent tryptophane, and no phosphorus was found. The purified material could be activated to thrombin by dissolving the prothrombin in concentrated solutions of sodium citrate, ammonium sulfate, magnesium sulfate, sodium sulfate, potassium citrate, potassium oxalate, and dipotassium hydrogen phosphate. Concentrated solutions of sodium chloride, potassium chloride, ammonium chloride or magnesium chloride do not produce activation. Difficulties were encountered when attempts were made to activate less highly purified prothrombin preparations with sodium citrate. The activation with sodium citrate is autocatalytic, and the yield of thrombin can be increased to a maximum by adding a small amount of 3-methyl-4,6,4'-triaminodiphenyl sulfone to the activation mixture. The sodium citrate concentration must be high, preferably near 25 per cent. A new method for preparing thrombin is based on the use of these principles. During activation the electrophoretic properties of prothrombin change long before appreciable amounts of thrombin activity are found. These changes in electrophoretic properties are associated with a prothrombin derivative which is refractory to the action of the activators calcium plus thromboplastin plus Acglobulin. When activation with sodium citrate is complete almost none of the material which had electrophoretic mobility of prothrombin is found in the electrophoresis boundary patterns. The major portion of the pattern is comprised of two components having mobilities less than prothrombin while a third component with high mobility is especially evident in the descending boundary pattern. Solubility studies indicate that two proteins may possess thrombin activity, but the evidence is not conclusive. An attempt was made to separate the proteins in the thrombin preparation by fractionation with ammonium sulfate, and it was found that their properties are so similar that this procedure is not effective. Thrombin obtained by activation of prothrombin with sodium citrate may be dried from the frozen state and is stable. Prothrombin is not stable after drying in this manner; however, it can be dried with acetone. It is reasoned that since sodium citrate and other salts can produce thrombin from prothrombin, the latter must contain all the structural material needed for the thrombin. For that reason calcium, thromboplastin, and Ac-globulin are regarded as catalysts of prothrombin activation and not as activators which must contribute material substance in prothrombin activation.

Metabolic signalling and the partitioning of resources in plant storage organs

1999 ◽  
Vol 133 (3) ◽  
pp. 243-249 ◽  
Author(s):  
NIGEL G. HALFORD
Keyword(s):  
Dry Weight ◽  
Wild Relatives ◽  
Crop Plants ◽  
Wild Plants ◽  
Young Plant ◽  
Carbon And Nitrogen ◽  
Cultivated Potato ◽  
Metabolic Signalling ◽  
Storage Organs ◽  
Plant Storage

The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

Electron Microscopy of the Nucleic Acid of Mouse Mammary Tumor Virus

1968 ◽  
Vol 26 ◽  
pp. 22-23
Author(s):  
N. H. Sarkar ◽  
Dan H. Moore
Keyword(s):  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Ammonium Acetate ◽  
Dry Weight ◽  
Mouse Tumor ◽  
Mammary Tumor Virus ◽  
Rna Molecules ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
The Subject

Mouse mammary tumor virus (MTV) is believed to contain about 0.8% single stranded ribonucleic acid (RNA). This value of RNA content was estimated on a dry weight basis. The subject of this report is an attempt to visualize the RNA molecules of MTV particles.MTV particles were isolated from RIII mouse (tumor incidence approximately 80%) milk according to the method described by Lyons and Moore. Purified virions from 5 ml of milk were finally suspended in 0.2 ml of PBS, pH 7.4 and was mixed with an equal volume of pronase (5 mg/ml). This mixture was incubated at 37°C for an hour. RNA was extracted three times using freshly prepared cold phenol. It was then treated three times with cold ethyl ether to remove any trace of phenol. The RNA thus extracted was divided into two parts. One part was diluted four fold with 8M urea to avoid aggregation of the molecules. The other part was left untreated. Both samples were then mixed with an equal volume of 1M ammonium acetate, adjusted to pH 8.0 with NH3 containing chymotrypsin at a concentration of 0.01%.

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

A photoelectron microscope study of surfaces

1989 ◽  
Vol 47 ◽  
pp. 10-11
Author(s):  
W. Engel ◽  
M. Kordesch ◽  
A. M. Bradshaw ◽  
E. Zeitler
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Field Strength ◽  
Uv Light ◽  
Physical Property ◽  
Photon Flux ◽  
Mercury Lamp ◽  
Object Surface ◽  
The Sixties ◽  
Physical Features

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.

STEM measurement of subcellular water distributions

1993 ◽  
Vol 51 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
S.Q. Sun ◽  
S-L. Shi ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
Water Content ◽  
Internal Standard ◽  
Dry Weight ◽  
Dry Mass ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Bulk Water ◽  
Inelastic Electron ◽  
Scanning Transmission ◽  
Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

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