Contents Of Tubes Research Articles

Countercurrent Distribution Studies on Hamycin

Hamycin, a polyene antifungal antibiotic, was isolated by use of countercurrent distribution. A pattern was obtained by plotting the absorption at 383 mmu of the contents of the various tubes against the tube numbers. The results indicated that the antibiotic contained three fractions, a major fraction (peak 2) comprising 48% of the total activity and two minor fractions (peak 1 and peak 3) comprising 3.62 and 11.32%, respectively, of the total activity. The solid material was isolated by pooling the contents of the tubes containing the major fraction, concentrating this in vacuo, and cooling. The antibiotic activities of the three peaks were evaluated by use of a cup-plate assay method with Paecilomyces varioti as test organism. All three components showed antibiotic activity; however, the preparation obtained from the major fraction showed approximately a 7-fold increase in antibiotic activity, a doubling of the E(1cm) (1%) value at 383 mmu, and approximately a 2.5-fold decrease in the amino acid content in comparison with the starting material. There was an apparent correlation obtained by plotting the curves of the absorption at 383 mmu of the different tubes comprising the major fraction and their biological activities.

Liquid-liquid, discontinuous, counter-current solvent extraction for determination of trace constituents in geological materials—I: Extraction with solvents lighter than water

A new analytical technique for the determination of trace constituents in silicate rocks has been developed. This consists of the use of liquid-liquid, discontinuous, counter-current, solvent extraction in which the chloro-complexes of a number of elements are extracted into a ketonic solvent. Extraction into methyl isobutyl ketone is followed by spectrographic analysis of the contents of the individual extraction tubes, from which a series of extraction curves is plotted. These curves show that trace constituents of a silicate rock can be separated from the main constituents and can be fractionated from eachother. By the use of a solution of a granite-gneiss in 3 M hydrochloric acid and varying concentrations of this ligand as the aqueous phase in the extraction train, it is shown that a number of trace constituents can be isolated and hence enriched from the rock solution. The method appears to have the advantages of speed, flexibility, relative freedom from contamination and the fact that even weakly-extracted elements may be determined quantitatively. It is suggested that the technique may be suitable not only for the analysis of trace constituents in silicate rocks, but also as a separation method in radioactivation analysis. A further application may be the separation of different oxidation states of the same element, e.g., antimony(III) from antimony(V).

Thermal Inactivation of Heat-Resistant Bacterial Spores in Milk Concentrate at Ultra-High Temperatures

The heat resistance of spores of Bacillus coagulans WH-9, Bacillus stearothermophilus 1518, and Clostridium sporogenes (PA 3679) was determined in 3:1 milk concentrate and 0.067 M phosphate buffer (pH 6.2). Although spore inactivation was predominantly logarithmic, the survivor curves were usually curvilinear during the initial period of heat transfer from the heating medium to the contents of the thermal inactivation tubes. Unlike spores of B. coagulans or PA 3679, those of B. stearothermophilus required an exceedingly high heat activation treatment to obtain maximal spore counts. Also, it was apparent that 3:1 milk concentrate was effective in inhibiting the germination of spores of B. stearothermophilus. Thermal resistance curves based on six D-values, indicated F-values of 1.8, 11.7, and 4.3mm and z-values of 16, 21.9, and 20.3F, respectively, for spores of B. coagulans, B. stearothermophilus, and PA 3679 suspended in 3 :1 milk concentrate. Spores of the three organisms suspended in phosphate buffer showed F-values of 1.7, 10.3, and 3.4mm and z-values of 15.6, 21.2, and 19.7F.The thermal process used in 3:1 milk concentrate, namely 295F for 3.5sec including the come-up time, appears to be adequate to inactivate spores of B. coagulans and PA 3679, even when they are present in large numbers, and spores of B. stearothermophilus if they are present in low numbers.

Note on the equalization of the temperatures of interferometer tubes

This note is a description of two devices used for establishing and maintaining equality and uniformity of temperature for the contents of the twin tubes of Jamin interferometers. According to one method the tubes are closely wound from end to end with spirals of soft copper wire, s.w.g. 18. The other device consists of an aluminium chamber which during idle periods completely encloses the tubes. Shutters, covering the ends of the tubes, are removed prior to the carrying out of measurements.

A modification of the Thunberg methylene blue method with a device for stirring the contents of the vacuum tubes1

A modification of the Thunberg methylene blue method with a device for stirring the contents of the vacuum tubes¹

LIGNIFICATION OF MATURE PHLOEM IN HERBACEOUS TYPES

Secondary growth in the woody stems of gymnosperms and angiosperms often results in the formation of annual rings in the xylem, but in the phloem no similar arrangement of elements is usually to be observed. The sieve tubes, which are generally the principal elements of the phloem, are crushed at the end of each period of growth by the pressure of surrounding cells and tissues. To these changes taking place in the secondary phloem the term obliteration has been applied for a long time. The alterations are initiated by the disappearance of the contents of the sieve tubes at the end of each growth period, soon followed by a crushing and distortion of the sieve tubes, and, in the case of angiosperms, of companion cells also. The sieve plates may be broken down, and the wall of the sieve tube takes on a swollen appearance. In an advanced condition of obliteration, the lumen of the sieve tube entirely disappears, being represented only by a line, and the whole mass of crushed sieve tubes takes on a horn-like consistency. During these changes the structure of the phloem parenchyma does not appear to be affected. The term horn prosenchym (Horngewebe) was applied by Wigand (I863) to such a mass of crushed tissue. The principal facts concerning the transformations undergone by the phloem of woody angiosperms have been generally known since the time of this writer. Previous to this date both -Oudemans (I862) and Rauwenhoff (I869) appear to have described obliterated structures in the phloem, Oudemans in I855, and Rauwenhoff in I859. These two writers, together with Moeller (I875) and Tschirch (I889), showed the crushed tissue to be composed of obliterated sieve tubes. Tschirch pointed out that the sieve tubes, including cambiform cells and companion cells, having lost the principal portion of their contents at the end of the growing season, become pressed together through the turgor of neighboring cells, so that only a small, cleft-shaped lumen remains. He believed that a subsequent thickening of the wall does not take place. De Bary (I884) indicated some doubt as to the extent to which the cambiform cells of the phloem are affected in obliteration, although he described the crilshing of the sieve tubes. Bliesnick (I89I) found that the phloem parenchyma takes no part in obliteration. His conclusions are essentially the same as those of Tschirch with regard to the causes of obliteration. Lignification of sieve plates was found in Clematis, and in another case he mentions that he found complete lignification of the obliterated phloem elements. His results differ from those of previous investigators in that 239

Experiments on a quantitative and qualitative test for anti-beriberi vitamine

In 1912 one of us (C.F.) experimented with the anti-beriberi vitamine to see if it could not act as coferment in alcoholic fermentation. The experiments failed at that time, but now the subject through the work of Williams, Bachmann and Eddy has attained a new interest. Their results seem to prove that vitamine activity can be measured by growth of yeast cells and would permit of dispensing with animal experimentation in the initial stages of vitamine fractionation. Because of the uncertainty of the Bachmann fermentation test, and the complicated procedure of Eddy's test, it was thought desirable to develop a simple macro method. Our procedure is as follows: A yeast suspension is prepared according to the method of Eddy by shaking a loopful of 48 hours yeast culture in a definite amount of Naegeli's solution for 4 hours on a shaking machine. Duplicate tubes are then prepared containing: (1) yeast suspension + Naegeli, (2) vitamine sol. + Naegeli, and (3) vitamine sol. + yeast suspension + Naegeli. The tubes are incubated for 20 hours at 30° and the fermentation then interrupted by heating to 70° for a few minutes. The contents of the test tubes are then transferred to special centrifuge tubes, the bottom part of which ends in a capillary 2% cm. in length and divided in mm. The tubes are centrifuged at 2600 r.p.m. for 15 min. and the reading made without much delay as there is a tendency for the yeast cells to swell up slightly after a time. Sterility during the entire process, excepting centrifugation, is of paramount importance. The results obtained with this method were as follows: The procedure was so well standardized that the controls with yeast suspension alone were practically constant.

The inversion and determination of cane sugar

Sucrose is completely inverted by heating in a solution of picric acid. This fact has been made use of in the estimation of cane sugar in solutions and extracts. After the cane sugar is hydrolyzed by heating with picric acid under properly controlled conditions, the invert sugar formed is determined by a modified Lewis-Benedict colorometric method. Glucose and fructose are determined at the same time.The technic of the method is as follows: 1 c.c. of the clear liquid containing the sugars is transferred to each of two graduated narrow test tubes containing 2 c.c. saturated solution of picric acid. One of the tubes also contains 1 c.c. 20 per cent. sodium carbonate. The two tubes are then immersed into a bath of boiling water. After ten minutes 1 c.c. of 20 per cent. sodium carbonate is also added to the tube containing the acid mixture. After heating for 30 minutes the color in each tube has reached its maximum and they are allowed to cool. The contents of the tubes are diluted to a suitable volume and ma...

A comparative study of the Ehrlich and Salkowski tests for indol production by bacteria

One of the bio-chemical reactions extensively used for the identification of bacterial types is the production of indol from peptone in a peptone-water solution. Of the various tests that might be used for the detection of that substance the one most widely adopted in this country is the so-called Salkowski test (H2SO4 + KNO2). In Germany Bohme (1905) and in England Marshall (1907) have found, after a comparative study, that the Ehrlich reaction (Paradimethylamidobenzaldehyde + HCl) gives more uniform and constant results.This study was undertaken in order to obtain further light on the relative reliability of the two tests. Seventy-five organisms, representing the various members of the colon-typhoid group, were used. Duplicate peptone broth tubes of each strain were incubated at 37° C. for four days. The contents of the tubes was then divided in half and the half portions subjected respectively to the two tests.Twenty-eight of the seventy-five strains were positive in both duplicate tubes with both test...

Studies on the Relation of the Living Cells to the Transpiration and Sap-Flow in Cyperus. II

1. Stems of Cyperus cut and placed in water wither sooner than when a certain portion, not to exceed 20 cm., has been killed by steam. 2. When 20 cm. of the stem are killed by steam, the leaves wither in about 8 days, that is, in about the same time as the control plants. 3. The longer the portion of the stem killed with steam, the sooner the leaves above wither and dry. When 25 to 30 cm. of the stem are killed with steam, the leaves wither in 3-5 days. 4. No matter how long the section killed may be, the leaves on steamed stems never wither quite so quickly as those cut and not placed in water, but under the same conditions of light, temperature, and air moisture. 5. In Cyperus sufficient water to maintain the leaves turgid for 3-18 days will rise through a stem 15-60 cm. high, with a section 5-30 cm. long which has been killed with steam. 6. A certain amount of water is raised through the steamed portion, but it gradually diminishes in quantity from day to day, until the leaves become air dry (about 11 per cent of their dry weight of moisture). 7. The diminished water supply is partly due to a partial blocking of the vessels with a gumlike or resinous substance, which probably owes its origin to the disorganization of the contents of the sieve tubes caused by heating the stems. 8. The withering of the leaves above a steamed portion of the stem is probably caused more by the action of deleterious substances introduced into them from the dead cells than from lack of water. These poisonous substances are probably disorganization products caused by heating with steam. 9. The leaves of rooted plants, grown in nutrient solutions containing sterilized decoctions of the same plant, droop in 3-5 days, discolor and dry in 7-8 days. 10. The withering leaves above a portion of the stem killed with steam show all the symptoms of dying, namely, rapid loss of water after treatment, then a more uniform loss, rounding up and discoloration of the chloroplasts, and contraction of the mesophyll protoplasts. The leaves are apparently drying, not so much from lack of water as on account of the death of the cells from other causes. 11. Judging from the behavior and disorganization of the leaves on a stem, a section of which has been killed with steam, it is evident that this method of killing the cells is not a satisfactory one in order to settle the question as to the relation of the living cells to sapflow. 12. Killing a portion of the stem by applying wax heated to 110⚬ C. causes less apparent disorganization of the cells, less injury to the leaves above, and does not cause a marked immediate decrease in the transpiration. 13. Experiments in which 5-10 cm. of the stem are killed by treatment with picric acid, 95 per cent alcohol, or CuSO4, for 36-48 hours show that sufficient quantities of water may ascend through the poisoned portions to supply the transpiration need for a comparatively long period (90 days), and to allow the development of new branches. 14. Certain poisons (picric acid, chromic acid, and HgCl2) may greatly accelerate the amount of water evaporated in poisoned plants. Not all poisons act alike in this respect; HgCl2 causes the greatest amount of increase in water loss.

Streaming Movements of the Protoplasm in Pollen of Flowers

IT may, perhaps, not be generally known that pollen of flowers affords a convenient example of the circulation of protoplasm. If pollen from a fox-glove be placed in a solution of sugar at ordinary temperature in a drop-slide, the grains sprout within twenty minutes, and grow during several hours at an average rate of 1/10 millimetre per hour. The granules of protoplasm move in opposite streams side by side, turning at the lower end of the tube and inside the grain; the rate of motion may be calculated at I millimetre in one and a half to two minutes. The rapidity and duration of the streaming movement vary in different species; in the pollen of the fox-glove it seldom continues longer than five or six hours, but in that of the bee orchis it may be still observed on the third day, after the tubes have ceased to grow. Protoplasm which has been set free by the bursting of tubes or grains, continues to show signs of life for a longer period. The granular character of the protoplasm is less distinct in some species than in others, but with a sufficiently high power—1/8—a visible motion of the contents of pollen tubes appears to be common.

II. On the structure and development of vascular dentine

The nomenclature and classification of the varieties of dentine have hitherto been based solely upon the appearances discoverable in dried teeth; in the present communication the author seeks to amend and place upon a more satisfactory basis the grouping of these several kinds of dentine, by bringing to bear upon their arrangement observations upon the nature of the contents of those large tubes which give to the tissues their name of “vascular” dentine, and, more especially, observations upon the methods by which they are developed. Vaso-dentine is the term generally used to designate a variety of dentine exceedingly common in the class of Fish, in which the substance of the tooth is permeated by a number of anastomosing tubes, of considerable size, which have been called “medullary’ canals, as they have been supposed to contain pulp-tissue; whilst osteo-dentine is used to designate that variety of vaso-dentine in which the matrix is arranged in concentric layers round the canals, like the laminæ of an Haversian system in bone, and in which spaces like the lacunae of bone occur.