• Food Science and Preservation
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• v.12 no.1
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• pp.48-53
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• 2005

Comparative effects between commercial fumigation (methyl bromide/MeBr, phosphine $gas/PH_3$) and gamma irradiation (5, 10 kGy) on dried red pepper were investigated in terms of it microbiological quality, moisture content Hunter's colors, and UV-visible spectra during storage for 8 months at mom temperature. The non-treated control samples showed total aerobic bacteria as $4.8\times10^5\;CFU/g$ in powdered state and $1.8\times10^2\;CFU/g$ in whole red repper. While yeasts and molds were $1.7\times10^5\;CFU/g$ in powdered pepper and $5.0\times10^2\;CFU/g$ in whole pepper, respectively. The effect of chemical fumigant on microbial decontamination was negligible, whereas irradiation at 5 kGy was proven to reduce the microbial populations by 2 to 3 log cycles that could improve the hygienic quality of powdered pepper. Moisture content of the samples showed no noticeable changes resulting 1mm irradiation or fumigation. Immediately after treatments, irradiation or fumigation reduced Hunter's lightness (L), redness (a), and yellowness (b) of the samples (p<0.05), but there was no difference in color parameters between the control and all treated stoups after 4 months of storage. It was found that storage period was more influential than irradiation or fumigation to changes in moisture and color of dried red pepper and ie powder.

• Food Science and Preservation
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• v.11 no.4
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• pp.431-436
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• 2004

Associated with microbial decontamination and quarantine treatment of dried red pepper, the samples was gamma-irradiated (5, 10 kGy) and fumigated (methyl bromide/MeBr, phosphine/$PH_3$) to compare their Hunter's color (L, a, b, ${\Delta}E$) and sensory properties by types (whole, powder, pericarp, seed) during storage under room conditions($18{\pm}12^{\circ}C$). Whole pepper maintained higher lightness (L value) than other groups, while powdered pepper showed higher redness (a value) during storage. Immediately after treatments there was little difference in the overall color difference (${\Delta}E$) among the groups. After 8 months, a higher redness was observed in $PH_3$ group of whole pepper and 5 kGy group of powdered pepper, respectively(p<0.05). Redness of irradiated pericarps was apparently reduced following 8 months of storage and a similar pattern was found in fumigated samples. The yellowness (b value) of pepper seed was lowest in 10 kGy sample (p<0.05), but insignificant difference was observed among treatment groups with storage time. Sensory properties of whole and powdered peppery were little changed by both treatments under commercial conditions. Sensory scores of irradiated or fumigated samples were higher than that of non-treated control with storage time, which was more significant in the powdered than in the whole samples.

• Korean journal of applied entomology
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• v.53 no.1
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• pp.73-80
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• 2014

Postharvest insect pest control is necessary for agricultural industry including domestic consumer markets and exporting products to meet quarantine issue. Especially, the organic or environmentally friendly agricultural products do not fit to the traditional chemical postharvest treatments mostly using methyl bromide. As an alternative, a physical treatment called CATTS (controlled atmosphere and temperature treatment) has been developed to control various insect and mite pests on apple and several stone fruits. This study was designed to determine the CATTS conditions to control the oriental fruit moth, Grapholita molesta, which is restricted in exporting the infested apples. To apply CATTS on this insect pest, the most heat-tolerant stage was determined. Among the immature stages locating on the fruits, the fifth instar larvae were the most tolerant to $44^{\circ}C$ for 20 min. The ramping rate (the time to increase chamber temperature from $25^{\circ}C$ to $46^{\circ}C$) was positively correlated with the CATTS efficiency under 15% $CO_2$ and 1% $O_2$. After the ramping step, the duration of CATTS was positively correlated with CATTS efficiency. In addition, the CATTS efficiency was highly dependent on the fruit internal temperature at $44^{\circ}C$. From all these parameters, we developed a standard protocol yielding 100% control efficiency of CATTS against apples infested by 4,378 larvae including 2,104 fifth instar individuals.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.33-37
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• 1961

We have shown that carboxy-peptidase destroys the biological activity of angiotensin octa-and deca-peptides. Since Proline occurs as the seventh amino acid from the amino end of the chain and since carboxypeptidase does not cleave proline from a peptid chain, it is evident that the heptapeptid H.asp-arg-val-tyr-ileu-his-pro.OH is formed by this hydrolysis. This peptide must then be biologically inactive. In order to determine whether the phenyl group of the C-terminal amino acid was the necessary requirement for biological activity of the octapeptide, $ala^8$ angiotensin octapeptide(amino acids of peptides numbered from amino end) was synthesized. For this synthesis the four dipeptides were prepared: carbobenzoxy-L-prolyl-L-alanine-P-nitrobenzyl-ester, m.p. $134-135^{\circ}C,$ carbobenzoxy-L-isoleucyl-imidazole benzyl-L-histidine methyl ester, m.p. $114-116^{\circ}C,$ carbobenzoxy-L-valyl-L-tyrosine hydrazide and carbobenzoxy B-benzyl-L-aspartyl-nitro-L-arginine. The first three dipeptides were obtained as crystalline compounds. Imidazole-benzyl-L-histidine was used in the hope that it would block the histidine imidazole against side reactions in steps subsequent to the formation of the C-terminal tetrapeptide. Also, it was through that the imidazole benzylated peptides would be easier to crystallize. This, however, was not the case. The tetrapeptide, carbobenzoxy-L-isoleucyl-L-im, benzyl-histidyl, L-prolyl-L-alanine-nitrobenzyl ester was not obtained in a crystalline form. Neither could the mono-or dihydrobromide of the tetrapeptide free base be induced to crystallize. Carbobenzoxy-L-valyl-L-tyrosine azide was condensed with the tetrapeptide free base to yield the protected hexapeptide; carbobenzoxy-L-valyl-L-tyrosyl-L-isoleucyl-L-im, benzyl, histidyl-L-Prolyl-L-alanine-nitrobenzyl ester. Upon removal of the carbobenzoxy group with hydrogen bromide in acetic acid an amorphous free base hexapeptide ester was obtained. This compound gave the correct C, H, N analysis and contained the six amino acids in the correct ratio. The octapeptide was obtained by condensing this hexapeptide with carbobenzoxy-B-benzyl-L-aspartyl-nitro, L-arginine using the mixed anhydride method of condensation. This amorphous product was proven to be homogenous by chromatography in two solvent systems and upon hydrolysis yielded the eight amino acids in correct ratio. The five protecting groups were removed from the octapeptide by hydrogenolysis over palladium black catalyst. Biological assay of the free peptide indicated that it possessed less than 0.1 per cent of both pressor and oxytocic activity of the phenylalanine8 angiotensin. This suggests that the phenyl group is a point of attachment between angiotensin and its biological receptor site.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.6
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• pp.531-540
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• 2022

Group 1 metabotropic glutamate receptors (mGluRs) can positively affect postsynaptic neuronal excitability and epileptogenesis. The objective of the present study was to determine whether group 1 mGluRs might be involved in synaptically-induced intracellular free Ca²⁺ concentration ([Ca²⁺]_i) spikes and neuronal cell death induced by 0.1 mM Mg²⁺ and 10 µM glycine in cultured rat hippocampal neurons from embryonic day 17 fetal Sprague-Dawley rats using imaging methods for Ca²⁺ and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays for cell survival. Reduction of extracellular Mg²⁺ concentration ([Mg²⁺]_o) to 0.1 mM induced repetitive [Ca²⁺]_i spikes within 30 sec at day 11.5. The mGluR5 antagonist 6-Methyl2-(phenylethynyl) pyridine (MPEP) almost completely inhibited the [Ca²⁺]_i spikes, but the mGluR1 antagonist LY367385 did not. The group 1 mGluRs agonist, 3,5-dihydroxyphenylglycine (DHPG), significantly increased the [Ca²⁺]_i spikes. The phospholipase C inhibitor U73122 significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The IP₃ receptor antagonist 2-aminoethoxydiphenyl borate or the ryanodine receptor antagonist 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate also significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The TRPC channel inhibitors SKF96365 and flufenamic acid significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The mGluR5 antagonist MPEP significantly increased the neuronal cell survival, but mGluR1 antagonist LY367385 did not. These results suggest a possibility that mGluR5 is involved in synaptically-induced [Ca²⁺]_i spikes and neuronal cell death in cultured rat hippocampal neurons by releasing Ca²⁺ from IP₃ and ryanodine-sensitive intracellular stores and activating TRPC channels.

• Journal of Korean Society of Forest Science
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• v.81 no.2
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• pp.156-163
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• 1992

Pinus koraiensis (Pk), P. rigida (Pr) and P. rigida ${\times}$ P. taeda (Pr. t) seedlings in a bare-rooted nursery were artificially inoculated with Pisolithus tinctorius (Pt) and Thelephora terrestris (Tt) to test long term effects of ectomycorrhizal inoculation on host growth. Mycelial inocula of Pt and Tt were mass-cultured in vermiculite-peatmoss mixture and introduced into fumigated nursery soil before seed sowing. Bare-rooted, inoculated seedlings at one to four years of age were outplanted to the field with $P_2O_5$ content of 25 ppm in soil. At the time of outplanting, Pk seedlings(4 years old), Pr seedlings(2 years old), and Pr.t seedlings(1 year old) all infected by Pt were significantly taller by 28%. 26%, and 77%, respectively, than controlled seedlings infected by natural population of mycorrhizal fungi in the non-fumigated plot. Ten years after inoculation or six to nine years after outplanting, Pk seedlings inoculated with Pt were significantly taller by 9% Pr.t seedlings significantly taller by 18%, and Pr slightly Caller by 2%(not significant) than controlled seedlings, suggesting that the stimulatory effect of Pt on host growth gradually declined or became minimal after outplanting. Tt failed to stimulate host growth either in the nursery or in the field, and the survival rate of outplanted seedlings was not different among fungal treatments. Considerable loss of the infected root system during lifting the seedlings for outplanting would be the primary cause of the reduced effect of Pt in the field. Pt infected more than 90% of the fine roots in the fumigated nursery during the first growing season, but Pt assumed to fail to compete successfully with natural population of ectomycorrhizal fungi in the field. It is necessary to select other mycorrhizal fungi which adapt well in both nursery and field.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.316-324
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• 2022

Ethyl formate (EF) is a potent fumigant replacing methyl bromide. The use of EF is limited to a quarantine process. Appling EF to agricultural field as a safe insecticide in greenhouse give us valuable benefits including less residual concern. In this regard, residual pattern after EF fumigation in greenhouse should be undertaken. In the previous study, we have established agricultural control concentration of EF to control pests in a greenhouse. EF was fumigated at 5 g m^-3 level for 2 h. The concentration of EF inside a greenhouse was analyzed to be 4.1-4.3 g m^-3 at 30 min after fumigation. To prepare an analytical method for residues in cucumber crops and soil in the greenhouse, the limit of detection(LOD) of the method was 100ng g^-1 and the limit of quantitation(LOQ) of this method was 300 ng g^-1. R² values of calibration curves for crops and soil were 0.991-0.997. In samples collected immediately after ventilation, EF concentration was determined to be below LOQ level. In addition, EF level was below LOQ in samples collected at 3 h after ventilation except that leaf samples of melon during the flowering period showed a level of 1,068.9 ng g^-1. Taken together, these results indicate that EF used in quarantine can be applied to agricultural fields without residual issue as an effective fumigant for insect pest control.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.193-203
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• 2023

Ethyl formate (EF) is a naturally occurring insecticidal compound and is used to control pests introduced from abroad, in quarantine, by a fumigation method. In particular, it is mainly used as a substitute for methyl bromide and is less toxic to humans and less harmful to plants. This study aimed to investigate the possible acute toxicity of EF to useful organisms, and how to reduce phytotoxicity in watermelon, zucchini, and oriental melon. After fumigation with EF for 2 h, the LC₅₀ values for earthworms, honey bees, and silkworms were 39.9, 7.09, and 17.9g m^-3, respectively. The degree of susceptibility to EF was in the order of earthworms, silkworms, and honey bees based on the LC₅₀ value, and EF fumigation induced stronger acute toxicity to honey bees. Phytotoxicity was observed in watermelon leaves treated with a concentration of 7.5 g m^-3 EF, and when treated with a concentration of 10.0g m^-3, it was confirmed that the edges of watermelon leaves were charred and seemed to be damaged by acids. Zucchini and melon, and other cucurbits, showed strong damage to the leaves when treated with a concentration of 10 g m^-3, and sodium silicate, at concentrations of 10% and 20%, was used to reduce phytotoxicity. Therefore, acute toxicity towards nontarget organisms and phytotoxicity during the fumigation of EF should be reduced for efficient agricultural pest control.