• Journal of Plant Biology
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• 제25권3호
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• pp.135-151
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• 1982

This investigation was carried out to clarify the changes of pigments and soluble protein, and photosystem II activity in the leaves of barley (${SO}_2$-sensitive) and corn (${SO}_2$-resistant) seedlings induced by the ${SO}_2$ fumigation (10, 50ppm). The pH changes of the leaf extract, the content of sulfite and sulfate, the activities of catalase, peroxidase, and polyphenoloxidase were compared in the leaves of barley and corn seedlings induced by ${SO}_2$ fumigation. The results are summarized as follows: An appreciable effect of pH change of leaf extract by ${SO}_2$ fumigation was observed in barley leaves (pH 6.10 to 5.18), but only a small change occurred in corn leaves (pH 5.66 to 5.50). The same pattern of pH changes was recorded when the solution of 0.2N HCl was added to leaf extract, providing lower buffering capacity of the barley leaves than corn leaves. After 2 hours of exposure to 10 ppm ${SO}_2$, the contents of ${SO}^{2-}_3$ and ${SO}^{2-}_4$ were increased in barley leaves, while only ${SO}^{2-}_4$ increased in corn leaves. After fumigation with 10ppm ${SO}_2$ for 2 hours, barley leaves showed significant decreases in activities of catalase, to 17% peroxidase, to 58%, and polyphenoloxidase, to 88%. Corn leaves showed increases in activities of peroxidase, to 136%, and polyphenoloxidase, to 128%. Absorption spectra of pigments obtained from ${SO}_2$-fumigated leaves were gradually decreased with the fumigation time increases, but the decrease was more significant in barley leaves. Fumigation with 50ppm ${SO}_2$ for 2 hours induced the greatest decomposition in carotenoid, followed by chlorophyll a and then chlorophyll b in barley leaves. The ratio of chlorophyll a/b was decreased from 4.1 to 3.6 in barley leaves, but in corn leaves it was maintained almost a constant level(4.9-4.8). The rate of decomposition of chlorophyll and carotenoid in corn leaves was very slow than those in the barley leaves. Fumigation with 50 ppm ${SO}_2$ for 2 hous, decreased the protein content of barley leaves to 59%, and that of corn leaves to 89%, and the extent of decrease in protein content was greater than that of pigments in barley and corn leaves. The rate of DCIP9dichlorophenol indophenol) photoreduction in ${SO}_2$-fumigated leaves was decreased to 18 and 67% in barley and corn leaves, respectively. However, DCIP photoreduction was considerably recovered about 32 and 92% with the addition of DPC(diphenylcarbazide) as an exogenous electron donor in barley and corn leaves, respectively.

• 한국균학회지
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• 제41권3호
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• pp.192-196
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• 2013

진균의 분화과정은 다양한 환경요인에 의하여 영향을 받는다. 모델 사상성 진균인 Aspergillus nidulans의 경우 빛이 존재하거나 높은 염 농도, 비 발효성 당에 의하여 무성분화가 촉진되며 반대로 빛이 없거나 발효성 당이 풍부할 때, 그리고 저산소 조건일 경우 유성분화를 촉진하게 된다. 또한 veA나 nsdD와 같은 유성생식 양성조절유전자들도 유성분화를 유도하는 것으로 알려져 있다. 본 연구에서는 A. nidulans에서 $CO_2$의 농도와 분화패턴의 관계를 알아보고자 하였다. 정상적인 조건에서 $veA^+$ 야생형 균주는 유성생식과 무성생식이 균형을 이룬 상태의 분화를 진행하게 된다. 그러나 5% 정도의 높은 $CO_2$ 조건에서 배양하였을 경우 무성분화는 일어나지 않고 유성생식으로만 분화과정이 일어나게 된다. 뿐만 아니라 이러한 분화 양상은 veA와 nsdD에 의존적으로 일어나게 된다. 고농도의 $CO_2$ 조건이라 할지라도 $veA^-$ 혹은 $nsdD^-$ 돌연변이 균주에서는 유성분화는 일어나지 않고 무성분화만이 일어나는 것을 관찰할 수 있었는데, 이는 $CO_2$ 농도가 높아져도 유성생식에 있어서 이들 유전자의 기능이 필요하다는 것을 시사한다. 또한 5% $CO_2$ 조건은 인간 병원성 진균에게 있어서 사람의 신체 내에 살아남기 위하여 적응하여야 하는 대기 조건으로, 이러한 A. nidulans의 $CO_2$ 농도에 따른 분화양상의 변화는 A. fumigatus와 같은 인간 병원균의 생리, 분화적 변화에 대한 비교분석에 사용될 수 있다.

• 대한임상검사과학회지
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• 제38권3호
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• pp.166-172
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• 2006

Metallo-${\beta}$-lactamase (MBL) can hydrolyze all ${\beta}$-lactams except monobactams and frequently coexists with various antibiotic resistance genes such as aminoglycoside resistance, sulfonamide resistance gene, etc. Therefore, the effective antibiotics against infections by these bacteria are markedly limited or can't even be found. We tried to search in-vitro antimicrobial combinations with synergistic effects for a VIM-2 type MBL producing Pseudomonas aeruginosa, isolated from clinical specimen. On the selection of antibiotic combinations with synergistic effects, we performed a one disk synergy test, modified Pestel's method, in agar without aztreonam (AZT). The bacteriostatic synergistic effects of this tests were scored as $S_1$ (by susceptibility pattern in agar without antibiotics), $S_2$ (by the change of susceptibility in agar with or without antibiotics) and $S_3$ ($S_1$ + $S_2$) and was classified into weak (1 point), moderate (2 points) and strong (3 points) by $S_3$ score. Subsequently, we carried out the time-killing curve for the antibiotic combinations with the strong synergistic bacteriostatic effect. One VIM-2 type MBL producing P. aeruginosa confirmed by the PCR showed all resistance against all ${\beta}$-lactams except AZT, aminoglycoside and ciprofloxacin. In the one disk synergy test, this isolate showed a strong bacteriostatic synergistic effect for the antibiotic combination of AZT and piperacillin-tazobactam (PIP-TZP) or AZT and amikacin (AN). On the time-killing curve after six hours of incubation, the colony forming units (CFUs/mL) of this bacteria in the medium broth with both combination antibiotics were decreased to 1/18.7, 1/17.1 of the least CFUs of each single antibiotics. The triple antibiotic combination therapy including AZT, PIP-TZP and AN was shown to be significantly synergistic after 8 hrs of exposure. In a VIM-2 MBL producing P. aeruginosa with susceptibility for AZT, the triple antibiotic combination therapy including AZT, PIP-TZP and AN may be considered as an alternative antibiotics modality against the infection by some MBL type. But the antimicrobial combination therapy for many more MBL producing isolates is essential to know as soon as possible for the selection of effective treatment against the infection by this bacteria.

• The Korean Journal of Physiology
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• 제22권1호
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• pp.13-29
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• 1988

In order to elucidate the regulatory mechanism of intracellular calcium ion concentrations, contractions or contractures induced by $Na^{+}-removal$, calcium-application or ouabain-treatment as an index of $Na^+/Ca^{2+}$ exchange activity were studied in atrial muscle or vascular smooth muscle (aorta and renal artery) of the rabbit. The magnitude of low sodium contractures in atrial trabeculae increased with sigmoid shape when external sodium concentrations were reduced to sodium-free condition, whereas that of calcium contracture intensified in a parabolic pattern when external calcium concentrations were elevated to 8 mM. $Na^{+}-removal$ contractures were induced in a duration-dependent manner to $K^{+}-free$ exposure and same findings were observed with ouabain treatment. $Na^{+}-free$ contractures were not affected by verapamil treatment, but stimulated by $100{\mu}M\;Mn^{2+}$ and inhibited by high concentrations of $Mn^{2+}\;(2{\sim}8mM)$ in a dose-dependent manner. Ryanodine which is known to suppress the release of calcium from internal store abolished spontaneous twitch contractions induced by $K^{+}-free$ solution, but had no effect on the development $Na^{+}-free$ contractures. Na-free contractures were not always induced in vascular smooth muscle preparations. Contractures by $O\;mM\;Na^+$ were usually seen in aorta, but not often in renal artery.$50\;mM\;K^+$, noradrenaline (NA) and angiotensin II (AII) always evoked very large contraction in all preparations of vascular smooth muscle. Contractures developed by $O\;mM\;Na^+$ were not sensitive to verapamil treatment as in atrial trabeculae, but were abolished by $100{\mu}M\;Mn^{2+}$. In contrast to $Na^{+}-free$ contractures, $Mn^{2+}(100{\mu}M)$ had no effect on the contractures induced by NA or 50 mM$K^+$. Caffeine in the concentration of 10 mM evoked transient contracture in the distal renal artery. The rate of spontaneous relaxation in caffeine contracture was dependent upon the concentrations of external sodium, and had double component of relaxation when the rate of relaxation was plotted in the semilogarithmic scale of relative tension versus time. Especially late components of relaxation had more direct relation to $Na^+$ concentrations. It could be concluded that $Na^+/Ca^{2+}$ exchange mechanism in the heart has a large capacity, inhibited by $Mn^{2+}$ but not by verapamil and ryanodine, while $Na^+/Ca^{2+}$ exchange system in vascular smooth muscle has a very low capacity especially in small artery, inhibited by low concentration of $Mn^{2+}\;(100{\mu}M)$ but not affected by verapamil and ryanodine.

• The Korean Journal of Physiology and Pharmacology
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• 제11권1호
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• pp.1-7
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• 2007

Altered environmental gravity, including both hypo- and hypergravity, may result in space adaptation syndrome. To explore the characteristics of this adaptive plasticity, the expression of immediate early gene c-fos mRNA in the vestibular related tissues following an exposure to hypergravity stimulus was determined in rats. The animals were subjected to a force of 2 g (twice earth's gravity) for 1, 3, or 12 h, and were examined poststimulus at 0, 2, 6, 12, and 24 h. RT-PCR (reverse transcription polymerase chain reaction) and real-time quantitative RT-PCR were adopted to analyze temporal changes in the expression of c-fos mRNA. The hypergravity stimulus increased the expression of c-fos mRNA in the vestibular ganglion, medial vestibular nucleus, inferior vestibular nucleus, hippocampus, cerebellum, and cortex. The peak expression occurred at 0 h poststimulation in animals stimulated with hypergravity for 1 h, and at 6 h poststimulus in those stimulated for 3 h. In contrast, those stimulated for 12 h exhibited dual peaks at 0 and 12 h poststimulus. Bilateral labyrinthectomy markedly attenuated the degree of c-fos mRNA expression. Glutamate receptor antagonist also dramatically attenuated the degree of c-fos mRNA expression. These results indicate that expression of c-fos mRNA in response to hypergravity occurs in the vestibular related tissues of the central nervous system, in which peripheral vestibular receptors and glutamate receptors play an important role. The temporal pattern of c-fos mRNA expression depended on the duration of the hypergravity stimulus.

• Parasites, Hosts and Diseases
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• 제33권3호
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• pp.187-194
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• 1995

정상 흰쥐의 출생 후 연령과 면역억제된 흰쥐의 감염강도에 따른 혈청 내 폐포자충(Pneumocystis carinii)에 대한 항체 형성을 관찰하고자 이 연구를 수행하였다. 폐포자충을 발현시키고 순수분리하여 수용성 항원을 만들고 이를 이용하여 전기영동과 면역이적법(Immunoblot)과 효소면역법(ELISA)을 시행하여 항체반응을 관찰하였다. SDS-PAGE에 의하여 분리된 항원의 단백 질 분획은 20-200 kDa의 범위에서 20개 이상이 관찰되었다. 이들 분획 중에서 인체 양성표준 혈청에 116 kDa 분획이 강하게, 45-55 kDa 및 100 kDa 분획이 약하게 반응하였고, 흰쥐 양성표준 혈청과는 40-45 kDa 분회과 강하게 그리고 50-55 kDa, 116, 200 kDa 분획과 약하게 반응하였다. 연령 별로 이 네 분획과의 반응을 보면 출생 5일-6주까지 양성률 50-100%이고 8주에는 0% 가 되었고, 10주 이후에는 증가하여 40주에 100%가 되었다. 폐포자충의 감염량이 증가하여 감염 강도가 IV인 흰쥐에서는 면역이적으로 측정할만큼 항체를 가진 개체가 없었다. 이러한 정상과 면역 억제된 흰쥐의 혈청반응 유형은 효소면역법에서도 확인할 수 있었다. 네 항원 분획 중 40-45 kDa에 대한 혈청반응이 각 군에서 낮게 관찰되었으나 그 생물학적 의의는 아직 평가하기 어렵다. 이 결과는 흰쥐가 출생하면 모체에서 유래한 혈청 내 항폐포자충 항체를 8주가 경과하면서 모두 소실하고 그 이후에 10주부터 40주에 이르기까지 자연감염에 의해 항체를 서서히 형성하는 것을 의미한다. 면역 억제에 의하여 흰쥐가 항체를 효과적으로 생산하지 못하게 되면 혈청 내 항체량에 반비례하여 폐포자충의 감염량이 늘어난다. 이는 항체에 의해 매개되는 체액면역이 폐포자충의 감염과 직접 관련이 있다는 증거가 된다.

• Pediatric Infection and Vaccine
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• 제4권2호
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• pp.218-224
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• 1997

목 적 : 전 세계적으로 폐구균의 항균제 내성이 증가하고 있고, 우리 나라의 경우 그 어느 나라보다 급속한 폐구균 내성의 증가가 보고 되고 있다. 일반적으로 상기도에 정착되어 있던 폐구균은 부비동염, 중이염, 수막염, 폐렴들을 일으키는 것으로 알려져 있어 저자들은 정상 소아의 구인강에서 폐구균의 보균율을 알아보고 이들의 항균제 내성양상과 DNA분자 형별을 조사하였다. 방 법 : 1997년 4월 서울 한 유치원의 어린이 117명에서 구인강 점막을 면봉으로 도말하여 검체를 얻었다. 이들을 배양후 optochin검사와 capsule에 대한 다가항체를 이용하여 Latex 방법으로 폐구균을 동정하였고, 디스크확산법으로 페니실린, vancomycin, erythromycin, TMP-SMZ에 대한 감수 검사를 시행하였다. 분리된 폐구균에 대하여 액체배지 미량 희석법을 이용하여 페니실린의 MIC값을 구하였다. 또 분리된 폐구균들에 대하여 REP1R-Dt와 REP2-Dt primer를 사용한 rep-PCR법으로 DNA 분자 형별을 시행하였다. 결 과 : 서울지역의 유치원에서 폐구균 보유율은 38%(45/117)였고, 디스크 확산법에 의한 페니실린 내성 폐구균의 비율은 89%(40/45)였고, erythromycin은 91%, TMP/SMZ은 63%였고 vancomycin에는 모두 감수성을 보였다. 그리고 페니실린에 고도 내성균주는 21예로 전체의 47%를 차지하였고 다제내성 폐구균은 64%였다. DNA 분자형은 7가지로 분류할 수 있었고, 이중 3가지 유형이 전체의 78%를 차지하였다. 결 론 : 서울 지역의 건강한 유치원 어린이들이 보유하고 있는 폐구균의 항균제 내성이 예상보다 훨씬 높았고, 이는 이들 어린이들이 빈번한 항균제 노출과 유치원의 밀집환경의 때문이라 추정된다.

• 한국패류학회지
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• 제25권3호
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• pp.223-230
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• 2009

Metallothioneins (MTs) play a key role in metallic homeostasis and detoxification in most living organisms. In an attempt to study the biological functions and significance of MT in a snail, we cloned and partially characterized the MT gene from the left-handed snail, Physa acutawhich has been regarded as a potential biomonitering species for fresh water. The complete cDNA sequence of PaMT cDNA was identified from the expressed sequence tag (EST) sequencing project of Physa acuta. The coding region of 180 bp gives 60 amino acid residues including the initiation methionine and termination codon. Clustering and phylogenic analysis of PaMT with other MT amino acid sequences show that it has some identities to Helix pomatia (60%), Arianta arbustorum (58%), Perna viridis (49%), Mytilus edulis (49%), Bathymodiolus azoricus (49%), Bathymodiolus azoricus (48%) and Bathymodiolus sp. FD-2002 (48%). Time dependent induction for PaMT from P. acuta exposed with cadmium (50 ppb) indicated that PaMT was induced at 4-8 hr after exposure. It remains to further develop PaMTas a potential biomarker for water contamination in fresh water.

• 한국토양비료학회지
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• 제18권4호
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• pp.413-418
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• 1985

질소원(窒素源)을 달리한 배양액(培養液)으로 담배식물의 양분흡수와 생육반응을 조사한 결과 1. $NO_3-N$ 배양액에서 자란식물은 양분 흡수가 크게 촉진되었다. $NH_4-N$ 배양액에서 자란식물보다 $NO_3-N$의 흡수로 무기양(無機陽)이온의 흡수가 현저하게 증가되었고 그중 K의 흡수가 가장컷으며 처리직후부터 빠른 흡수속도로 총질소(總窒素)는 2배(倍), K, Ca, Mg는 모두 3배 이상 높았다. 그리고 $NO_3+NH_4$ 혼합배양액(混合培養液)에서는 $NO_3-N$ 선택흡수(選擇吸收)되는 경향을 보였다. 2. 담배식물이 자란 배양액의 산도(酸度)는 질소원별로 상이(相異)하여 $NO_3-N$ 배양액은 알카리쪽으로 미미하게 변하지만 $NH_4-N$ 배양액에서 산성(酸性)쪽으로 큰 변화를 나타냈고 $NO_3+NH_4$ 혼합액(混合液)도 산성(酸性)쪽으로 변하지만 $NH_4-N$단독배양액보다는 크지 않았다. 3. 담배식물의 생육반응은 $NO_3-N$ 배양액에서 가장 양호하게 나타났으나 $NH_4{^+}$을 함유한 배양액에서는 생육이 부진하였으며 특히 $NH_4-N$ 단독배양액에서는 생육이 거의 정지되었다.

• Journal of Animal Science and Technology
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• 제63권3호
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• pp.531-544
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• 2021

Heat stress (HS) damages health and decreases performance variables in pigs, and if severe enough, causes mortality. However, metabolic changes under HS and recovery following HS are poorly understood. Therefore, this study was aimed to expose the essential mechanisms by which growing pigs respond to HS and the temporal pattern of plasma concentrations (PC) of amino acids (AAs) and metabolites. Crossbred male growing pigs were penned separately and allowed to adapt to thermal-neutral (TN) conditions (20℃ and 80% relative humidity; TN[-1D]). On the first day, all pigs were exposed to HS for 24 h (36℃ and 60% relative humidity), then to TN conditions for 5 days (TN[2D] to TN[5D]). All pigs had ad libitum access to water and 3 kg feed twice daily. Rectal temperature (RT) and feed intake (FI) were determined daily. HS pigs had higher RT (40.72℃) and lower (50%) FI than TN(-1D) pigs (p < 0.01). The PC of indispensable (threonine, valine, and methionine) and dispensable (cysteine and tyrosine) AAs were higher (p < 0.05) in HS than TN(-1D) pigs and remained increased during recovery time. Nonprotein α-aminobutyric acid and β-alanine concentrations were higher (p < 0.05) in HS than TN(-1D) pigs. The metabolite concentration of creatinine was higher (p < 0.01) under HS treatment than other treatments, but that of alanine and leucine remained increased (p < 0.05) through 5 d of recovery. In summary, some major differences were found in plasma AA profiles and metabolites between HS- and TN-condition pigs. This indicates that the HS pigs were forced to alter their metabolism, and these results provide information about mechanisms of acute HS responses relative to the recovery time.