Changes in Flavor Components of Onion by γ-Irradiation

The effect of γ-irradiation on the flavor of Onions (Senshu Yellow) associated with sprout-inhibition has been investigated. The relative amounts of propionaldehyde, n-propyl mercaptan and di-n-propyl disulfide in onions stored for 0, 5, 10, 20 and 30 days, respectively, after irradiation were estimated by measurement of peak areas of gas chromatograms. It was observed that the lachrymatory character and the pungent flavor had been decreased by γ-irradiation (remarkably at 70 and 700 Krads). In this connection, the amounts of propionaldehyde and di-n-propyl disulfide were decreased with increasing radiation dose and storage period at room temperature (20 to 25°C) and at low temperature (4°C). Moreover, it was observed that the sweetness had been decreased by γ-irradiation, but the amount of n-propyl mercaptan was increased with radiation dose and storage period. Therefore it seems that there is no correlation between the sweetness of onion and the amount of n-propyl mercaptan.     

Decomposition Pathways of p-Bromophenol on γ-Irradiation in Aqueous Systems

In order to elucidate the radiolysis mechanism of p-bromophenol, quantitative determination of the radiolysis products was carried out by gas chromatography and polarography. G(?p · BP) and G(Br^?) were 3.86 and 2.58 at neutral pH, and 1.09 and 0.26 at pH 1.0, respectively, This, together with the radical scavenger effects indicated that hydrated electrons contribute principally to the degradation of p-bromophenol through debromination, followed by the formation of dimer and trimer products by phenylation of the resulting p-hydroxyphenyl radical. This chain-like reaction may cause the difference (G-value = 1.28) between G(?p· BP) and G(Br^?). The contribution of OH radicals to G(?p· BP) is known to be small as compared with other aromatic compounds, because of the poor yield of hydroxylated products such as hydroquinone, 4-bromocatechol and 4-bromoresorcinol.     

γ-Irradiation of Barley Seeds and Its Effect on the Phytohormonal Status of Seedlings

We investigated the effect of γ-irradiation (4–50 Gy) of barley seeds (Hordeum vulgare L., cv. Nur) on the content of endogenous phytohormones–stimulators of plant growth and development: indol-3-acetic acid (IAA), indolyl-3-butyric acid (IBA), zeatin and abscisic acid (ABA). The ratio (IAA + IBA + zeatin)/ABA from the third to the seventh day of germination has been measured. It was shown that the changes in the content of phytohormones as a function of the radiation dose were nonlinear. In the dose range of 4–20 Gy, phytohormones balance was changed due to increased content of growth stimulators and decreased ABA content. Using a dose of 50 Gy led primarily to a decrease in the content of growth stimulators and an increase in ABA content, and the ratio (IAA + IBA + zeatin)/ABA shifted toward ABA content.     

Effect of γ-butyrolactone derivative on an artificial membrane

trans-2-(6'Methylheptanol-1'-yl)-3-hydroxymethyl-4-butanolide(II) was shown to increase the passive flux of cations such as Co²⁺ through a black lipid membrane made from ox brain phospholipids. This membranotropic effect appears to be involved in the activity of II towards blocked mutants of streptomycetes as an autoregulator of cytodifferentiation.     

Effect of Continuous γ-Irradiation at Low Doses on Clonogenic Hemopoietic (CFU-S) and Stromal (CFU-F) Cells of Bone Marrow

We studied the effects of low doses of continuous -irradiation (Co⁶⁰, 10 days, mean daily dose power 1.5-2.0 mGy, total dose 15 mGy) on hemopoietic and stromal progenitor cells of murine bone marrow. The content of hemopoietic clonogenic cells representing a younger (CFU-S-11) and more mature (CFU-S-7) categories in the compartment of stem cells was determined in the bone marrow. The state of bone marrow stroma was estimated by the method of in vitro cloning according to the number of progenitor cells that form colonies of fibroblasts (CFU-F) and by the method of ectopic transplantation according to the capacity of stroma of organizing and building new hemopoietic territories. Continuous -irradiation at low doses, that were by one order of magnitude lower than those inducing hermesis, exerted a stimulating effect on both hemopoietic (CFU-S) and stromal (CFU-F) progenitor cells. The number of CFU-S in the compartment of stem cells of the bone marrow markedly increased and they formed larger hemopoietic territories but these cells appeared to create a qualitatively different microenvironment, which stimulated the proliferation of CFU-S.     

Effect of Rifampin on the Development of Ribonucleic Acid Bacteriophage Qβ

The drug rifampin, when added at the time of infection, inhibits synthesis of the phage Qbeta. Both viral ribonucleic acids and viral proteins are made in nearly the same amount as in the absence of rifampin, but the rate of assembly into phage particles is low.     

Isolation of Deficiencies in the Arabidopsis Genome by γ-Irradiation of Pollen

Chromosomal deficiencies are a useful genetic tool in fine-scale genetic mapping and the integration of physical and visible marker genetic maps. Viable overlapping deficiencies may permit gene cloning by subtractive procedures and provide a means of analyzing the functional importance of different chromosomal regions. A method is described for isolation of deficiencies in the Arabidopsis genome which encompass specific loci and other extended chromosomal regions. The technique employs pollen mutagenized by γ-irradiation to pollinate marker lines homozygous for recessive mutations. Deficiencies at specific loci were detected by screening for marker phenotypes in the F(1). Screening for lethal mutations in the F(1)/F(2) confirmed specific deficiencies and revealed other deficiencies that did not overlap the marker loci. Further evidence for such mutations was provided by distorted F(2) segregation of the chromosomal markers linked to putative deficiencies. Maintainable (transmissible) and non-transmissible deficiencies were demonstrated by their pattern of inheritance in subsequent generations.     

Induction of Mutation by γ-Irradiation in the Presence of Oxygen or Nitrogen

The effect of γ-irradiation on Aspergillus nidulans genes depends on the presence of oxygen.     

Effect of γ-radiation on some elements in certain organs of albino rats

Energy-dispersive X-ray fluorescence (EDXRF) was used to determine the concentrations of Ca, Cl, Fe, Ni, P, K, Se, S, and Zn in heart, lung, liver, spleen, and kidney of adult albino rats 2 mo after they were subject to a single gamma γ-radiation dose from⁶⁰Co at 5 gy. In female rats, K levels were significantly higher and the Ca levels significantly lower for the irradiated animals when compared to age-matched nonirradiated controls. Significant differences between irradiated and nonirradiated tissues were observed for other elements, although no sex-related differences could be found. Tissue damage and disturbances of biological functions were observed as a result of γ-irradiation.     

Effect of gabaculine on metabolism and release of γ-aminobutyric acid in synaptosomes

Synaptosomes isolated from mouse brain were incubated with [¹⁴C]glutamate and [³H]-aminobutyric acid ([³H]GABA), and then [¹⁴C]GABA (newly synthesized GABA) and [³H]GABA (newly captured GABA) in the synaptosomes were analysed. (1) the [³H]GABA was rapidly degraded in the synaptosomes, (2) when the synaptosomes were treated with gabaculine (a potent inhibitor of GABA aminotransferase), the degradation of [³H]GABA was strongly inhibited, (3) the gabaculine treatment brough about a significant increase in Ca²⁺-independent release of [³H]GABA with no effect on Ca²⁺-dependent release, (4) no effects of gabaculine on degradation and release of [¹⁴C]GABA were observed. The results indicate that there are at least two pools of GABA in synaptosomes and support the possibilities that GABA taken up into a pool which is under the influence of GABA aminotransferase is released Ca²⁺-independently and that GABA synthesized in another pool which is not under the influence of GABA aminotransferase is released Ca²⁺-dependently.     

Effect of Sterol Type on Structure of Tubules in Sterol + γ-Oryzanol-Based Organogels

The mixture of γ-oryzanol with β-sitosterol forms a network of tubules in edible oil that may serve as an alternative to the network of small crystallites of triglycerides occurring in regular oil structuring. The present experiments demonstrate that the tubules vanish at the melting point of the gel. Moreover, a number of alternative sterols (e.g., ergosterol, stigmasterol, cholesterol, cholestanol) can replace sitosterol in the tubules. The tubule diameter varies between 6.7 and 8.0 nm, the wall thickness between 0.8 and 1.2 nm. The results are consistent with a previously proposed helical ribbon assembly mechanism.     

Effect of γ-irradiation on pasting and emulsification properties of octenyl succinylated rice starches

Octenylsuccinylated (OS) starches from waxy rice or high-amylose rice (28.1% amylose) (DS 0.023 and 0.025, respectively) were gamma-irradiated at 10, 30, or 50kGy and their pasting and thermal properties, crystallinity, and emulsification property were examined. When the OS starches were irradiated, the degrees of substitution gradually decreased as irradiation dose increased. A significant decrease in pasting viscosity was observed with an increase in irradiation dose, indicating the presence of chain degradation induced by the radiation. The melting temperature and enthalpy determined by differential scanning calorimetry increased slightly by irradiating at 10 or 30kGy. Little change in crystallinity was observed in the X-ray diffraction analysis for the OS high-amylose rice starch regardless of irradiation doses, whereas a decrease in crystallinity was observed with the OS waxy starch irradiated at 50kGy. Chain degradation induced by irradiation occurred mainly in the amorphous regions, but some loss of crystallinity occurred when the irradiation was excessive. The OS starches showed greater emulsion capacity and stability than the native counterparts due to their amphipathic nature. The irradiation further improved the emulsification properties of OS starches. The irradiation at 10kGy was optimal, and treating at higher doses decreased the emulsion capacity and stability of the OS starches.     

Effect of γ-Decanolactone on Glutamate Binding in the Rat Cerebral Cortex

Epilepsy is one of the most common neurological disorders. Even though antiepileptic drugs can afford a reasonably satisfactory treatment for 80% of diagnosed patients, chronic intractable epilepsy still affects a significant number of people and more effective and less harmful antiepileptic drugs are needed. Previous studies have shown that -decanolactone has dose-dependent sedative effects, including hypnotic, anticonvulsant and hypothermic properties in mice. The present study reports an inhibitory effect of -decanolactone on glutamate binding (96.8% with 5 mM) in rat cortex membranes. The non competitive nature of glutamate binding inhibition as a neurochemical correlate of the anticonvulsant activity of -decanolactone may be a relevant mode of action for further drug development.     

Effect of prepropeptide replacement on γ-carboxylation and activity of recombinant coagulation factor IX

Biotechnology Letters - Based on observations indicating that the γ-carboxylase enzyme has a lower affinity for the protein C (PC) propeptide and that the γ-carboxylase region in the PC...     

Preferential Loss of Conjugated Carbonyl Compounds in Cooked Pork Fat by γ-Irradiation

Cooked pork fat was irradiated with γ-rays and volatile carbonyl compounds were spectrophotometrically examined after their conversion to 2,4-dinitrophenylhydrazones. The main change was preferential loss of conjugated carbonyls, e.g., deca 2,4-dienal. Under the deaerated condition, non-conjugated carbonyls did not change on irradiation. The loss was insensitive to the presence of oxygen, some electron and cation scavengers, and some excitation quenchers, but was somewhat prevented by the addition of laurylmercaptan or triphenylmethane. Some conjugated aldehydes added to the fat decreased on γ-irradiation. Various solvents were tested instead of the fat and conjugated aldehyde decreased more slowly in unsaturated solvents than in saturated ones. G(-conjugated aldehydes) value was estimated by using crotonaldehyde and the value of 0.8 was obtained.     

Effect of γ-glutamyl cycle inhibitors on brain amino acid transport and utilization

Two inhibitors of the -glutamyl cycle, methionine sulfoximine (MSO) and 2-imidazolidone-4-carboxylic acid (ICA) were administered to C57BL/6J mice. Both agents resulted in a reduced rate of transport of tyrosine from blood to brain and a decreased rate of incorporation of tyrosine from plasma into brain protein. MSO administration also diminished the concentrations of brain tyrosine, dopamine, and norepinephrine. MSO decreased the transport rate of valine by brain as well as the rate of its incorporation into protein when expressed in relation to the plasma specific activity. The results demonstrate a significant role for the -glutamyl cycle in the transport of large neutral amino acids from blood to brain.Presented in part in the April 1977 meeting of the American Academy of Neurology, Atlanta, Georgia.     

Enhancement of Regeneration Potential and Variability by γ-Irradiation in Cultured Cells of Scilla Indica

Induced mutagenesis in callus tissues was studied in the medicinal plant Scilla indica irradiated with different doses of -radiation ranging from 2.5 to 20 Gy. Low doses accelerated the cell division and growth rate of the tissues whereas high doses repressed growth rate and resulted in lethality of tissues. Various cytological and chromosomal abnormalities were observed in the irradiated calli, the degree of which depended upon the dosage. Low doses of irradiation also promoted the regenerating capacity of the calli tissues and plants regenerating from them exhibited better growth and vigour compared to normal plants. High doses led to loss of regenerating capacity and promoted formation of malformed and stunted plants. Cytological study of regenerants revealed both diploid and mixoploid plants but no tetraploids were obtained.     

Effect of the three-dimensional organization of liver cells on the biogenesis of the γ-glutamyltransferase fraction pattern

Context Four gamma-glutamyltransferase (GGT) fractions with different molecular weights (big-, medium-, small- and free-GGT) are detectable in human plasma. Objective Verify if liver cells can release all four GGT fractions and if the spatial cell organization influences their release. Methods Hepatoma (HepG2) and melanoma (Me665/2/60) cells were cultured as monolayers or spheroids. GGT released in culture media was analysed by gel-filtration chromatography. Results HepG2 and Me665/2/60 monolayers released the b-GGT fraction, while significative levels of s-GGT and f-GGT were detectable only in media of HepG2-spheroids. Bile acids alone or in combination with papain promoted the conversion of b-GGT in s-GGT or f-GGT, respectively. Conclusions GGT is usually released as b-GGT, while s-GGT and f-GGT are likely to be produced in the liver extracellular environment by the combined action of bile acids and proteases.