scispace - formally typeset
Search or ask a question

Showing papers on "Incubation published in 1971"


Journal ArticleDOI
TL;DR: In this paper, Wood Mountain loam samples were wetted to 20% moisture using either water, Ca(NO₃)₂, or (NH₄)µSO₆ solutions.
Abstract: Stored and fresh Wood Mountain loam samples were wetted to 20% moisture using either water, Ca(NO₃)₂, or (NH₄)₂SO₄ solutions. Half of the samples were sterilized with ethylene oxide. Fall conditions were imposed by incubating samples at diurual temperatures of 14 to 3C and early spring conditions by slow freezing to −23C followed by incubation at 14 to 3C or 8.5C. Exchangeable NH₄-N, NO₃-N, and microbial counts were determined at appropriate intervals. In the unamended and NO₃-amended soils, freezing followed by 16 days incubation at 14 to 3C had a bactericidal effect and resulted in a much lower rate of nitrification than freezing followed by incubation at 8.5C. Where NH₄ had been added the bactericidal effect was not as great and there was no difference in nitrification between the two incubation temperatures. Incubation at low temperatures impeded nitrification more than ammonification which resulted in an initial buildup of exchangeable NH₄. Ethylene oxide was an effective soil sterilant but caused a small increase in the exchangeable NH₄. Freezing followed by incubation at low temperatures increased the exchangeable NH₄ in sterile soils but did not affect the NO₃ content. There was evidence of an interaction between the length of soil storage and the various treatments (viz, freezing, sterilization, etc.).

99 citations


Journal ArticleDOI
TL;DR: By utilizing a shift down in temperature, biosynthesis of prodigiosin by washed cells could be separated from multiplication of bacteria, and measurements of viable count and of protein, plus other data, indicated that cellular multiplication did not occur in suspensions of washed cells during pigment formation.
Abstract: Maximal amounts of prodigiosin were synthesized in either minimal or complete medium after incubation of cultures at 27 C for 7 days. Biosynthesis of prodigiosin began earlier and the range of temperature for formation was greater in complete medium. No prodigiosin was formed in either medium when cultures were incubated at 38 C; however, after a shift to 27 C, pigmentation ensued, provided the period of incubation at 38 C was not longer than 36 hr for minimal medium or 48 hr for complete medium. Washed, nonpigmented cells grown in either medium at 38 C for 72 hr could synthesize prodigiosin when suspended in saline at 27 C when casein hydrolysate was added. These suspensions produced less prodigiosin at a slower rate than did cultures growing in casein hydrolysate at 27 C without prior incubation at 38 C. Optimal concentration of casein hydrolysate for pigment formation by suspensions was 0.4%; optimal temperature was 27 C. Anaerobic incubation, shift back to 38 C, killing cells by heating, or chloramphenicol (25 mug/ml) inhibited pigmentation. Suspensions of washed cells forming pigment reached pH 8.0 to 8.3 rapidly and maintained this pH throughout incubation for 7 days. Measurements of viable count and of protein, plus other data, indicated that cellular multiplication did not occur in suspensions of washed cells during pigment formation. By this procedure utilizing a shift down in temperature, biosynthesis of prodigiosin by washed cells could be separated from multiplication of bacteria.

97 citations


Journal ArticleDOI
TL;DR: Results are considered evidence for the conclusion that in the chick embryo the pituitary-adrenal axis is established by day 14.5 of incubation, and Pituitary transplants to hypophysectomized embryos partially restored allantoic fluid volumes to normal values.

75 citations


Journal ArticleDOI
TL;DR: In all experiments the specific activity of prolactin in the medium became significantly greater than that in the tissue, and was as high as 2.7 times that of the tissue in some cases.
Abstract: Adenohypophyses (AP) of female rats were exposed to 3H-leucine either in vivo or in vitro, then incubated in vitro. The prolactin (PI) in the tissues and incubation medium was separated and quantified by disc electrophoresis (DE) and densitometry. The PI bands were cut from the gel columns and counted by liquid scintillation procedures. In all experiments the specific activity of prolactin (cpm/μg) in the medium became significantly greater than that in the tissue, and was as high as 2.7 times that of the tissue in some cases. This indicated that prolactin was secreted in vitro from more than one pool, with the newly synthesized (labeled) hormone being rapidly released. One rapid turnover pool was indicated by an increase of as much as 100% in medium PI specific activity between 40 and 70 minutes of incubation of AP labeled in vivo one hour before incubation. This early increase did not occur with AP labeled in vivo 4 hours. Another less rapid turnover pool was suggested by a greater discrepancy between m...

67 citations


Journal ArticleDOI
TL;DR: When an exponentially growing culture of Escherichia coli is cooled to below 8 °C, initiation of protein synthesis appears to be blocked, while the elongation of initiated proteins continues until they are completed, demonstrated by showing that nascent polypeptide chains increase in size during a 5 °C incubation.

64 citations


Journal ArticleDOI
TL;DR: It was concluded that greatest numbers of viable larvae of largest size at yolk exhaustion would occur from incubation at 27.5–29.5‰ S and 6–7 C.
Abstract: Newly fertilized eggs were incubated at 13 combinations of levels of salinity and temperature between 20 and 35‰, and 4.1 and 8.5 C. Average egg density throughout development was 1.0252, and the incubation period ranged from 6.2 to 13.5 days. Larval length at mean hatching time averaged 2.84 mm for all trials. External features of the larvae are described. The percentages of eggs hatching (total hatch) and producing viable larvae (viable hatch) are examined with respect to salinities and temperatures of incubation. Calculated optima were: total hatch 29.47‰ S, 6.65 C; viable hatch 27.93‰ S, 7.00 C. At 6.3, 7.2, and 8.1 C, larvae grew to 5.5–5.7 mm total length prior to exhaustion of yolk 246–393 hr after hatching. It was concluded that greatest numbers of viable larvae of largest size at yolk exhaustion would occur from incubation at 27.5–29.5‰ S and 6–7 C.Laboratory results are related to available hydrographic and meteorological data for a spawning area off the west coast of Vancouver Island. Estimates...

59 citations


Journal ArticleDOI
TL;DR: The results demonstrate complex changes in cerebral amino acid transport during development, with several maxima or minima and with changes in specificity for at least some compounds.
Abstract: — 1 Upon incubation, slices of brain tissue took up fluid; the degree of swelling increased with increasing age. No sweiling occurred in slices from foetal brain. Since this swelling was associated with increases in the inulin space, the percentage of inulin space in slices at the end of incubation increased during brain development. 2 Most of the capacity for ion transport seemed to be absent from foetal brain. In vivo and in slices, Na+ was very high and K+ was very low in comparison to levels at other ages. There was a rapid change around birth, but no significant change at later ages. Upon incubation, Na+ levels increased in other slices, but not in slices of foetal brain. 3 Upon incubation of the slices, ATP levels were restored to levels close to those in the living brain; there were no significant alterations in available energy during development to explain changes in amino acid transport. 4 The composition of the free pool of cerebral amino acids in vivo changed with development, with some compounds (glutamic acid and related compounds) increasing, others (mostly‘essential’amino acids) decreasing, with age. These changes were not linear with time, and the level of a compound might exhibit several peaks during development. 5 The uptake (influx) of taurine, glutamate and glycine into brain slices increased rapidly during the foetal and early neonatal periods, reached a maximum between 2 and 3 weeks of postnatal age and then declined to adult levels. The levels of steady-state uptake with glycine also exhibited a maximal peak at 2-3 weeks of postnatal age. Steady-state uptake of taurine and glutamate reached adult levels by about 3 weeks of age. 6 The pattern of inhibition of amino acid transport by two specific amino acid analogues changed during development for some amino acids (GABA, glycine and glutamate), indicating an alteration in substrate specificity. 7 The results demonstrate complex changes in cerebral amino acid transport during development, with several maxima or minima and with changes in specificity for at least some compounds.

54 citations


Journal Article
TL;DR: The rate of recovery of Pratylenchus brachyurus from cotton roots was enhanced when the tissue was incubated in solutions containing 10 ppm ethoxyethyl mercuric chloride, 50 ppm dihydrostreptomycin sulfate, 50, 100, or 1,000 ppm diisobutylphenoxethyl dimethyl benzyl ammonium chloride, or mixtures of these compounds.
Abstract: The rate of recovery of Pratylenchus brachyurus from cotton roots was enhanced when the tissue was incubated in solutions containing 10 ppm ethoxyethyl mercuric chloride, 50 ppm dihydrostreptomycin sulfate, 50, 100, or 1,000 ppm diisobutylphenoxethyl dimethyl benzyl ammonium chloride, or mixtures of these compounds. Incubation in 10 or 100 ppm zinc sulfate, zinc chloride, or magnesium chloride also enhanced the rate of recovery. Incubation solutions containing 1 or 1,000 ppm zinc chloride or magnesium chloride had no influence on this phenomenon, whereas, 10,000 ppm zinc sulfate, zinc chloride, or magnesium chloride retarded the rate of recovery. A t all incubation intervals during the first 21 days after the roots were removed from soil, the P. brachyurus population consisted of approximately 25% second-stage juveniles, 44% third and fourth-stage juveniles, and 31% females. At least 88% of the second-stage juveniles and 51% of the third and fourth-stage juveniles passed through a single 325-mesh sieve, whereas, 84% of the females collected were retained on a sieve of this mesh. Key Words: Gossypium hirsutum, Extraction, Incubation.

43 citations


Journal ArticleDOI
TL;DR: Results of various gassing levels for the two 4-day periods of 17-20 and 18-21 days respectively involved a fluctuating response to high O2 levels, followed by a decreased resistance, then by a reversal of trend toward a very high resistance in the 13-16 day period.

41 citations


Journal ArticleDOI
TL;DR: The formation of ammonia and changes in the contents of free amino acids have been investigated in slices of guinea pig cerebral cortex incubated under the following conditions: aerobically in glucose‐free saline, an inhibitor of glutamate dehydrogenase, and anaerobic in saline.
Abstract: The formation of ammonia and changes in the contents of free amino acids have been investigated in slices of guinea pig cerebral cortex incubated under the following conditions: (1) aerobically in glucose-free saline; (2) aerobically in glucose-free saline containing 10 mM-bromofuroic acid, an inhibitor of glutamate dehydrogenase (EC 1.4.1.2); (3) aerobically in saline containing 11-1 mM-glucose and (4) anaerobically in glucose-free saline. Ammonia was formed at a steady rate aerobically in glucose-free medium. The formation of ammonia was largely suppressed in the absence of oxygen or in the presence of glucose whereas the inhibitor of glutamate dehydrogenase produced about 50 per cent inhibition. Other inhibitors of glutamate dehydrogenase exerted a similar effect. Ammonia formation was also inhibited by some inhibitors of aminotransferases but not by others. Inhibition was generally more pronounced during the second and third hour of incubation. With the exception of glutamine which decreased slightly, the contents of all amino acids increased markedly during the anaerobic incubation. During aerobic incubation in a glucose-free medium, there was an almost complete disappearance of glutamic acid and GABA. Glutamine also decreased, but to a relatively smaller extent. The content of all other amino acids increased during aerobic incubation in glucose-free medium, although to a lesser extent than under anaerobic conditions. The greater increase of amino acids appearing anaerobically in comparison to the increase or decrease occurring under aerobic conditions corresponded closely to the greater amount of ammonia formed aerobically over that formed anaerobically. This finding is interpreted as indicating a similar degree of proteolysis under anaerobic and aerobic conditions; aerobically, the amino acids are partly metabolized with the concomitant liberation of ammonia. In glucose-supplemented medium, the content of glutamine was markedly increased. The content of glutamate and aspartate remained unchanged, whereas that of some other amino acids increased but to a lesser extent than in the absence of glucose. Proteolysis in the presence of glucose was estimated at about 65 per cent of that in its absence. In the presence of bromofuroate the rate of disappearance of glutamate was unchanged, but there was a larger increase in the content of aspartate and a smaller decrease of GABA and glutamine. Other changes did not differ significantly from those observed in the absence of bromofuroate. We conclude that the metabolism of amino acids in general and of glutamic acid in particular differs according to whether they are already present within the brain slice or are added to the incubation medium. Only the endogenous amino acids appear to be able to serve as precursors of ammonia and as substrates for energy production.

39 citations


Journal Article
TL;DR: It is concluded that immunologic memory can be expressed by both the B- and the T-lymphoid cell lines in the mouse.
Abstract: Transfers of normal and/or immune BALB/c spleen cells into x-irradiated syngeneic recipients were performed in order to characterize further the nature of memory cells. Incubation of the cells with antisera to either the θ-antigen or to mouse immunoglobulin in the presence of C was used to remove selectively T-cells (θ-bearing) or B-cells (Ig-bearing). Primary and secondary responses to Brucella abortus (BA) were reduced by incubation with anti-Ig but were unaffected by removal of T-cells, suggesting the thymus-independence of this response. Responses to sheep erythrocytes (SE) were always greatly inhibited after incubation of the cells with anti-θ, while being reduced to a variable extent by anti-Ig. With DNP-hemocyanin as the antigen, primary and early memory responses were unaffected by anti-θ, whereas the late memory response to this antigen was greatly reduced by such treatment. Addition of equal numbers of untreated normal spleen cells to antisera treated immune spleen cells resulted in minimal reconstitution of the memory responses. Such reconstitution was only obtained by recombination of anti-θ and anti-Ig treated immune spleen cells. It is concluded that immunologic memory can be expressed by both the B- and the T-lymphoid cell lines in the mouse.

Journal ArticleDOI
TL;DR: Reasons are given for considering incubation fluids as artificial extensions of the interstitial fluid of the brain, and for regarding amino acid output from the tissue as a process counterbalancing axoplasmic flow.
Abstract: The content of 12 amino acids in guinea pig cerebral cortical tissues was measured before and after incubation in glucose salines. The incubation caused reltively little change in tissue content, but induced a considerable production and accumulation of amino acids in the incubation medium. The dietarily essential amino acids, found in uncombined form, increased 3 to 6 fold. Glycine and alanine also increased; little change occurred in the quantity of free aspartic and glutamic acids. Amino acids were retained in the tissue in vitro against concentration gradients considerably higher than those estimated to obtain in vivo; by superfusing the tissue, the ratios were further increased. Electrical stimulation of the isolated tissues increased the amino acid accumulating in the medium during incubation, and increased the efflux of radioactive leucine during superfusion. Cycloheximide also increased the efflux of radioactive leucine during superfusion, while colchicine was found to decrease the proportion of total amino acid appearing in superfusates. Reasons are given for considering incubation fluids as artificial extensions of the interstitial fluid of the brain, and for regarding amino acid output from the tissue as a process counterbalancing axoplasmic flow.

Journal ArticleDOI
TL;DR: It is concluded that if soil pentose originates by microbial synthesis it must accumulate slowly by a long process of selective decomposition of a mixture of polysaccharides.
Abstract: Summary Incubation of soil with monosaccharide for 224 days resulted in the evolution of about 80 per cent of the substrate carbon as CO2 and the transformation of 3 per cent to soil sugars whether the substrate was 14C-glucose or xylose and whether the soil was pH 7.4 or pH 5.0. There was no detectable change in the total amounts of individual sugars in the soil during incubation. 14C-glucose and xylose gave the same distribution of radioactivity among the soil sugars : hexoses and 6-deoxy-hexoses were initially well labelled, with glucose having twice the specific activity of the other sugars. As the incubation progressed some activity appeared in the pentoses (the activity in xylose became very low within the first 14 days of the 14C-xylose incubation) and that in the hexoses slowly declined, with glucose no longer predominant. Nevertheless after 448 days the hexoses were still 3–4 times more radioactive than the pentoses. The activity in rhamnose did not decline with time so that eventually it became the most strongly labelled sugar. Incubation of soil with glucose and 14C-acetate showed very little transformation of the acetate to sugars indicating that glucose is not metabolized to C2 compounds before it is transformed to other sugars. Ammo-acids in soil incubated for 7 days with 14C-glucose had much lower levels of radioactivity than hexoses or 6-deoxy-hexoses. It is concluded that if soil pentose originates by microbial synthesis it must accumulate slowly by a long process of selective decomposition of a mixture of polysaccharides.

Journal ArticleDOI
TL;DR: Disc gel electrophoretic patterns showed that breakdown of the salt-soluble proteins had occurred after incubation for 20 days in pork muscle inoculated with Pseudomonas fragi, and most of the proteolytic activity appeared immediately after spoilage occurred.
Abstract: Considerable salt-soluble protein degradation was observed in pork muscle inoculated with Pseudomonas fragi. During a 20-day incubation period at 10 C, the samples proceeded to rank spoilage or putrefaction. There was a large decrease in the salt-soluble protein fraction and a corresponding increase in nonprotein nitrogen. Disc gel electrophoretic patterns showed that breakdown of the salt-soluble proteins had occurred after incubation for 20 days. During incubation for 10 days at 10 C, P. fragi produced large amounts of extracellular proteolytic activity in ground pork. Most of the proteolytic activity appeared immediately after spoilage occurred. However, a significant increase in the ability to hydrolyze casein and a slight increase in the ability to hydrolyze denatured hemoglobin occurred prior to spoilage.

Journal ArticleDOI
TL;DR: Addition of dimethyl sulfoxide (DMSO) to the cytochemical incubation medium for succinate dehydrogenase was attempted to accelerate penetration with consequent shortening of the incubation time, and less heterogeneity in reaction product was obtained in the mitochondria of muscle.
Abstract: Addition of dimethyl sulfoxide (DMSO) to the cytochemical incubation medium for succinate dehydrogenase was attempted to accelerate penetration with consequent shortening of the incubation time. The copper-ferrocyanide medium for demonstration of succinate dehydrogenase activity was applied to fresh and hydroxyadipaldehyde-fixed muscle of the hamster and mouse and the albumen secreting gland cells of the hen oviduct. Cytochemical evidence indicated that DMSO did not seem to inhibit this enzymatic activity. With a shorter incubation time, less heterogeneity in reaction product was obtained in the mitochondria of muscle. The marked heterogeneity found in the reaction in the intracristal space of mitochondria also was diminished with addition of DMSO to the medium. The gland cells, whose ultrastructure was not well preserved with prolonged incubation, showed reductase reaction with the DMSO-containing medium.


Journal ArticleDOI
TL;DR: The active uptake ofl-aspartic acid, glycine andl-lysine by actidione-treated cells ofSaccharomyces cerevisiae was found to be inhibited by anaerobic conditions in the absence of a source of energy, only facilitated diffusion persisting.
Abstract: The active uptake ofl-aspartic acid, glycine andl-lysine by actidione-treated cells ofSaccharomyces cerevisiae was found to be inhibited by anaerobic conditions in the absence of a source of energy, only facilitated diffusion persisting. Similarly, metabolic inhibitors (iodoacetamide, sodium fluoride and potassium sorbate) inhibited the uptake very substantially. 2,4-Dinitrophenol and sodium azide appeared to inhibit the movement of the transport carrier itself, while uranyl ions showed a complex interaction pattern, ranging from inhibition at concentrations of 10−6–10−4m, to stimulation at concentrations of 3×10−4–10−3m, to pronounced inhibition at higher concentrations. The uptake was pH-dependent with optima forl-aspartic acid near pH 4, for glycine near pH 5, forl-lysine near pH 6.5.

Journal ArticleDOI
TL;DR: Rumen fluid from calves 3 to 5 weeks old showed an increase in octadecadienoic acid on incubation at the expense mainly of 18:0 and 18:1, while in calves given dry feed an opposite pattern began to appear at about five weeks, indicating hydrogenating activity.

Journal ArticleDOI
TL;DR: Incubation of Aspergillus ochraceus NRRL 3174 in a medium containing Na(36)Cl incorporated ( 36)Cl into ochratoxin A resulted in the lowest incorporation and the highest incorporation was obtained when the radioactive chloride was added to the medium by the 2nd or 3rd day of incubation.
Abstract: Incubation of Aspergillus ochraceus NRRL 3174 in a medium containing Na36Cl incorporated 36Cl into ochratoxin A. The highest incorporation (0.75 and 0.70%, respectively) was obtained when the radioactive chloride was added to the medium by the 2nd or 3rd day of incubation.

Journal ArticleDOI
Dolan Ct1, Darlene M. Ihrke1
TL;DR: A study of the comparative efficiency of human and sheep sera in producing germ tubes revealed that both were equally effective; however, the cost of commercially obtained sheep serum is about one third that of human serum; thus, it is more economical to use sheep serum.
Abstract: An evaluation of the optimal incubation time for the germ-tube test used in the rapid identification of Candida albicans revealed that a 2-hr. incubation will identify 78% of the strains, whereas a 3-hr. incubation will identify 94% of the strains tested. Extending the incubation to 4 hr. increases the strains identified by only 1%. A study of the comparative efficiency of human and sheep sera in producing germ tubes revealed that both were equally effective. However, the cost of commercially obtained sheep serum is about one third that of human serum; thus, it is more economical to use sheep serum.

Journal ArticleDOI
TL;DR: Nitrogen mineralized during aerobic incubation and NH₄⁺⁻N after incubation of amended soil under waterlogged conditions were among the better predictors of both N uptake and relative increase in N uptake.
Abstract: Biological and chemical methods for obtaining an index of soil N availability to a test crop under different levels of N fertilization were evaluated on 15 Kentucky soils having a range of organic matter contents of 0.72 to 2.79%. Organic matter, N mineralized during aerobic incubation at 30C or 40C for 7 or 14 days, and extractable NH₄⁺⁻N after incubation under waterlogged conditions for 7 or 14 days at 30C and 14 days at 40C were all significantly related to N uptake and relative increase in N uptake by ‘X-1605’ grain sorghum (Sorghum vulgares) during 18 weeks of growth in the greenhouse. When the soils were amended in the laboratory with P and K or P, K, and Ca and incubated under waterlogged conditions, the relationship between extractable NH₄⁺⁻N and N uptake by sorghum improved greatly over unamended soils. Nitrogen mineralized during aerobic incubation and NH₄⁺⁻N after incubation of amended soil under waterlogged conditions were among the better predictors of both N uptake and relative increase in N uptake.

Journal ArticleDOI
TL;DR: It was concluded that light could act to trigger the hatching process and that functioning of this mechanism coincided with the development of the visual system in the chick.

Journal ArticleDOI
TL;DR: It is shown that the oxidation of long chain and short chain fatty acids conforms with the mechanism shown in adult mammalian tissue, and a change in heart mitochondrial composition or function with development is suggested.


Journal ArticleDOI
TL;DR: It is suggested that the development of induced respiration is dependent upon the synthesis of RNA and protein.

Journal ArticleDOI
John S. Elce1
01 Jun 1971-Steroids
TL;DR: The principal water-soluble compound formed on incubation of estradiol and glutathione in the presence of horseradish peroxidase has been assigned the structure of S-(3,17β-dihydroxy-9,10-secoestra-1,3,5(10)-trien-9-one-10-yl)-glutathione (II).

Journal ArticleDOI
12 Mar 1971-Nature
TL;DR: Inactivation of serum by heating always prevented a decrease in the free cholesterol during incubation, and any increase of total and free cholesterol in the serum after incubation with arterial segments could be taken as a measure of egress of cholesterol from the arterial wall.
Abstract: SPERRY1 was the first to demonstrate in vitro esterification of cholesterol, reporting that incubation of human serum and plasma at 37° C for 3 days decreased free cholesterol without changing total cholesterol. He also showed that esterification of free cholesterol during incubation could be inhibited by heating serum to 55°–60° C for 1–2 h, and suggested that this procedure resulted in enzyme inactivation. Glomset and Wright2 showed a similar inhibition of cholesterol esterification after heating serum for 30 min at 56° C; this has been confirmed by others3,4 as well as by us. There is evidence that the heat-labile enzyme is lecithin–cholesterol–acyl–transferase (LCAT) which seems to react preferentially with high density lipoproteins to catalyse the transfer of fatty acids from the 2-position of lecithin to the hydroxyl group of free cholesterol. Murphy4 has demonstrated an equilibrium between free cholesterol of serum and that of the red blood cells, and shown that the flux of free cholesterol from cells to serum increases as the free cholesterol of the serum becomes esterified during incubation. If there was a similar equilibrium between free cholesterol of the serum and of the arterial tissue, the rate of esterification of free cholesterol might be an important factor in similarly allowing more cholesterol to leave the arterial wall. To test this hypothesis segments of human iliac arteries which appeared from gross examination to be free of atherosclerosis were removed at autopsy in sterile conditions, washed with cold saline, stripped of adventitia and the wall turned inside out, so that the intimal surface was then external, and the ends were sewn together6. These arterial segments were used immediately or stored frozen and dried in sterile tubes until needed. Fasting blood samples were drawn from healthy volunteers, without the use of anticoagulants, defibrinated and centrifuged at 3,000g for 10 min. The serum was removed and used immediately for all incubation procedures. The serum was first separated into two large aliquots, one of which was heated at 56° C for 30 min to inactivate LCAT enzyme. Samples of both untreated and inactivated serum were incubated for 6 h at 37° C. The decrease in serum free cholesterol concentration recorded after incubation was a measure of LCAT activity. Inactivation of serum by heating always prevented a decrease in the free cholesterol during incubation. Three iliac arterial segments, equal in size and area, and removed from the same necropsy and prepared as described, were used for subsequent incubation experiments. One segment was first heated at 56° C for 30 min to inactivate any LCAT enzyme from the arterial wall and the other two were untreated. Incubations for 6 h at 37° C were then carried out in the following conditions: 5 ml. aliquots of serum (untreated) were incubated with arterial segments (untreated); a similar untreated aliquot of serum was incubated with an inactivated arterial segment, and an aliquot of inactivated serum was incubated with an untreated arterial segment. Incubations were carried out in small sealed Erlenmeyer flasks to which oxygen had been added. The flasks were placed in a Dubnoff shaker to mix the serum and arterial intima. At the end of incubation arterial segments were carefully lifted and any serum adhering to the intima was allowed to drain off for 15 min. The total and free cholesterol concentrations were then determined by the method of Zak et al.7 on all serum samples for all the conditions described. The data on initial LCAT activity could be used as a measure of the expected decrease in free cholesterol with incubation of serum alone, and any increase of total and free cholesterol in the serum after incubation with arterial segments could be taken as a measure of egress of cholesterol from the arterial wall (Table 1). The decrease in free cholesterol when serum was incubated alone (A) occurs without any significant change in total cholesterol, the slight difference being compatible with a less than 2% error in the technique. Furthermore, the method of inactivation of the LCAT enzyme of the serum was dependable, the decrease in free cholesterol being negligible (B). Whenever arterial segments were incubated with serum, there was an increase in the mean total cholesterol concentration (C, D, E) regardless of prior inactivation. When serum was inactivated before incubation with the arterial wall (C) there was no change in the concentration of free cholesterol, which increased, however, after incubation of untreated serum regardless of any prior inactivation of the arterial wall (D, E). The lower part of Table 1 shows that there was a similar egress of total and free cholesterol from the arterial wall after incubation with untreated serum. The negligible increase of free cholesterol in the inactivated serum (C-B) is significantly different from the other two conditions at the P< 0.001 level. But there are no significant differences in the increase in total cholesterol for all the groups. Thus when LCAT enzyme is absent from the incubation medium, only cholesterol ester seems to leave the arterial wall, whereas when LCAT enzyme is present, virtually only free cholesterol seems to leave the arterial wall.

Journal ArticleDOI
TL;DR: In this paper, the incorporation of 35S-labeled chondroitin sulfate (35S-Ch) into cultured Chinese hamster cells was studied quantitatively and the uptake is characterized as a function of the incubation time, the concentration of 35 S-Ch in the medium, and is dependent on pH and temperature of incubation medium.

Journal ArticleDOI
TL;DR: Embryonic development was slower in injected eggs than in eggs from treated females, and rate of uptake by quail embryos increased throughout the incubation period.
Abstract: Adult female Japanese quail (Coturnix coturnix japonica) were dosed orally with pp'-DDT in order to produce residues of pp'-DDT and pp'-DDE in their eggs. Eggs were incubated and insecticide uptake by the developing embryos and chicks was compared with the results of other authors, who had injected chicken eggs with insecticide solution before incubation. Rate of uptake by quail embryos increased throughout the incubation period. At hatching and 2 days after hatching, the yolk sac was estimated to contain mean amounts of 37% and 7%, respectively, of the total residues in the chick. Quail eggs, without detectable organochlorine residues, were injected with either pp'-DDT or pp'-DDE in olive oil. At 6 days incubation significantly more DDE than DDT was found in the embryo, but this trend had stopped by 10 days incubation. Metabolism of pp'-DDT to pp'DDE was first detected after 9 days incubation. Embryonic development was slower in injected eggs than in eggs from treated females.

Journal ArticleDOI
TL;DR: Residual DMSO can be removed from the cornea prior to transplantation by increasing the time of postthaw incubation in the albumin solution or by incubating in Kinsey medium.