• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.357-366
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• 2019

We first confirmed the involvement of MalQ (4-${\alpha}$-glucanotransferase) in Escherichia coli glycogen breakdown by both in vitro and in vivo assays. In vivo tests of the knock-out mutant, ${\Delta}malQ$, showed that glycogen slowly decreased after the stationary phase compared to the wild-type strain, indicating the involvement of MalQ in glycogen degradation. In vitro assays incubated glycogen-mimic substrate, branched cyclodextrin (maltotetraosyl-${\beta}$-CD: G4-${\beta}$-CD) and glycogen phosphorylase (GlgP)-limit dextrin with a set of variable combinations of E. coli enzymes, including GlgX (debranching enzyme), MalP (maltodextrin phosphorylase), GlgP and MalQ. In the absence of GlgP, the reaction of MalP, GlgX and MalQ on substrates produced glucose-1-P (glc-1-P) 3-fold faster than without MalQ. The results revealed that MalQ led to disproportionate G4 released from GlgP-limit dextrin to another acceptor, G4, which is phosphorylated by MalP. In contrast, in the absence of MalP, the reaction of GlgX, GlgP and MalQ resulted in a 1.6-fold increased production of glc-1-P than without MalQ. The result indicated that the G4-branch chains of GlgP-limit dextrin are released by GlgX hydrolysis, and then MalQ transfers the resultant G4 either to another branch chain or another G4 that can immediately be phosphorylated into glc-1-P by GlgP. Thus, we propose a model of two possible MalQ-involved pathways in glycogen degradation. The operon structure of MalP-defecting enterobacteria strongly supports the involvement of MalQ and GlgP as alternative pathways in glycogen degradation.

• Journal of Microbiology
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• 제34권4호
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• pp.320-326
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• 1996

To analyze the effects of host versus plasmid on survival of 2, 4-degrading bacteria in environmental samples, strains Pseudomonas cepacia/pJP4, Alcaligenes JMP228/pJP4, P. cepacia/p712, and Alcaligenes JMP228/p712 were separately inoculated into samples of field soil, paddy soil, lake water, and river water, and then the changes of their populations were measured. The strains used contained a 2, 4-D degradative plasmid, either pJP4 conferring fast-growing property to the host or p712 conferring slow-growing property, and were resistant to antibiotics such that the inoculated strains could be enumerated against the indigenous microbial populations. In sterile environmental samples, these strains were stably maintained at the levels used for inoculation, except in sterile paddy soil where Alcaligenes JMP228 strains died drapidly. In natural soil samples for four strains declined steadily with time, but in naturla water samples their polulations fell rapidly at the early phase and then remained almost constant. When the environmentla samples were treated with 2, 4-D, P. cepacia/pJP4 and P. cepacia/p712 maintained significant numbers, while Alcaligenes JMP228/pJP4 and Alcaligenes JMP228/p712 declined significantly in most of the samples. The results indicated that the survivability of genetically modified microorganisms could vary depending on the environments and that their abundance in the environments under s2, 4-D selection was markedly influenced by the nature of the 2, 4-D degradative plasmid as well as type of the host strain.

• 유기물자원화
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• 제19권3호
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• pp.73-78
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• 2011

혐기성 수소 발효시 pH는 물질 대사 경로와 수소 생성 미생물의 활성에 직접적으로 영향을 미치는 가장 중요한 요소 중 하나로 알려져 있다. 본 연구는 음식폐기물로부터 운전 pH에 따른 혐기성 회분식수소 발효의 영향을 평가하기 위해 수행하였다. 5 N KOH 용액을 이용하여 초기 pH는 8.0으로 고정하였으며, 운전 pH는 4.7~7.0으로 유지하였다. 운전 pH가 낮을수록 지체 시간은 단축되는 것으로 나타났으며, 최대 수소 발생량은 낮게 나타났다. 운전 pH 4.7일 경우에는 지체 시간이 47.9 h으로 가장 길게 나타났으나, 최대 수소 발생량은 534.4 mL로 가장 높게 나타났다. 운전 pH가 증가함에 따라 지체 시간과 최대 수소 발생량은 감소하였다. 운전 pH 7.0일 경우에는 지체 시간이 4.2 h으로 나타났으며, 최대 수소 발생량은 213.8 mL로 나타났다.

• 대한화학회지
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• 제42권3호
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• pp.277-284
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• 1998

Siloxane tetramer$(Me(CH_2=CH)SiO)_4$를 중심분자로 한 나뭇가지꼴 거대분자(제1세대-제4세대)를 allylmagnesium bromide와 dichloromethylsilane를 이용한 alkenylation과 hydrosilation 반응를 통해 제조하였다. Dichlorosilyl기를 가진 G4세대와 p-bromophenol, p-phenylphenol, lithium phenylethynylide등과의 반응에서 특정기능을 가지는 G4P-BP(Mw: 16,300), G4P-PP(16,121), G4P-PA(11,764) 등이 합성되었다. 새롭게 형성된 나뭇가지꼴 거대분자는 NMR, UV, MALDI mass의 분석에 의해 균일한 구조를 가지고 있음이 확인되었다.

• 한국환경과학회지
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• 제8권2호
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• pp.227-231
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• 1999

This study was conducted to investigate the removal characteristics of $PO_4^{3-}-P$ contained in livestock wastewater using waste concrete. With small particle size, increased dosage and temperature of water, $PO_4^{3-}-P$ was well removed by waste concrete.$PO_4^{3-}-P$ was removed by adsorption reaction in low pH of the primary phase, but the crystallization reaction predominated for increasing pH with passed time. As a result of adapting the adsorption isotherm equation, $PO_4^{3-}-P$ removal was more affected by the crystallization reaction than the adsorption reaction. In the SEM micrograph, there was no evident change on the waste concreter surface. Particle size was plate-phase before reaction but appeared a dense form to progress in the crystallization reaction.

• Journal of Microbiology
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• 제45권6호
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• pp.534-540
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• 2007

The Streptomyces coelicolor A3(2) genome contains six operons (rrnA to F) for ribosomal RNA synthesis. Transcription from rrnD occurs from four promoters (p1 to p4). We found that transcripts from the p1 and p3 promoters were most abundant in vivo in the early exponential phase. However, at later phases of exponential and stationary growth, transcripts from the p1 promoter decreased drastically, with the p3 and p4 transcripts constituting the major forms. Partially purified RNA polymerase supported transcription from the p3 and p4 promoters, whereas pure reconstituted RNA polymerase with core enzyme (E) and the major vegetative sigma factor ${\sigma}^{HrdB}$ ($E{\cdot}{\sigma}^{HrdB}$) did not. In order to assess any potential requirement for additional factor(s) that allow transcription from the p3 and p4 promoters, we fractionated a partially purified RNA polymerase preparation by denaturing gel filtration chromatography. We found that transcription from the p3 and p4 promoters required factor(s) of about 30-35 kDa in addition to RNAP holoenzyme ($E{\cdot}{\sigma}^{HrdB}$). Therefore, transcription from the p3 and p4 promoters, which contain a consensus -10 region but no -35 for ${\sigma}^{HrdB}$ recognition, are likely to be regulated by transcription factor(s) that modulate RNA polymerase holoenzyme activity in S. coelicolor.

• 환경위생공학
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• 제9권2호
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• pp.1-7
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• 1994

Rainwater was collected in Seoul area from January 1991 to December 1993 (over 3years) and by the analysis of the chemical components contained in rainwater, investigated the components that effect on rainwater pH Through the above studies the following conclusions were obtained. 1) Method for Averaging pH Volume weighted method is considered to be acceptable providing that precipitation is measured at the same time when the samples are taken, without precipitation data a simple averaging method should be the next choice. 2) Annual average rainwater pH was 4.98 in 1991, 4.80 in 1992, 4.67 in 1993, measurement range was 3.6-8.1. 3) In the relationship between rainwater pH and rainfall amounts rainwater pH for light rain(<15mm rainfall) was existent in the wide range(pH 4-7), but for heavy rain was corresponded to the annual average values. 4) Annual frequency of pH was Birrndat the frequency($\gamma $) between the density of the [$H^{+}$] and pH in the rainwater(over 3years ), $NO_{3}^{-}$ was excellent and the obtained results was 0.62 in 1992. Also In the correlation coefficient($\gamma $) according to the pH range $SO_{4}^{2-}, NO_{3}^{-}$, were 0.85 ,0.68 at 3.6 $Cl^-$ was 0.99(1993). At 4.1$NO_{3}^{-}(\gamma=0.48)$ in 1992, SO_4^{2-}($\gamma$=0.54), $NO_{3}^{-}(\gamma$=0.72), $Cl^- (\gamma$=0.49) in 1993. 6) pH values gradually increased with increase in $Ca^{2+}/SO_{4}^{2-}$.

• KSBB Journal
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• 제20권1호
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• pp.46-49
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• 2005

생분해성인 curdlan을 아세틸화하여 소수성 약물인 IND의 치료효과를 증진시킬 수 있는 약물전달시스템 개발을 위한 실험을 수행한 결과, IND가 포함된 CAMs를 제조할 수 있었고, IND의 loading efficiency는 $58.44\%$였다. 약물 방출 거동에 영향을 미치는 요인 중 제조한 CAMs의 swelling 특성은 처음 1시간 동안 pH 1.4에서는 아무런 변화가 없었고 PH 7.4에서는 $30\%$의 swelling을 보였고 pH 1.4에서보다 pH 7.4에서의 swelling이 약 3배 높았다. 또한 CAMs로부터 IND의 방출은 pH 1.4에서보다 pH 7.4에서 약 15배 이상 증가하였다. 이러한 결과로 CAMs는 IND의 약물전달시스템으로 유용할 것이며 특히 pH에 의존하는 약물방출 경향을 보였다.

• 대한화학회지
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• 제20권3호
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• pp.221-228
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• 1976

$60{\%}$ dioxane 수용액에서 hydrazonyl bromide의 여러 유도체$(p-H,\;p-CH_3,\;p-OCH_3,\;p-Br,\;p-Cl\;및\;p-NO_2)$의 pH에 따르는 가수분해 반응속도를 $25^{\circ}C$에서 자외선 분광광도법으로 측정하여 넓은 pH 범위에서 잘 맞는 반응속도식을 구하였다. 가수분해 반응속도에 미치는 치한기효과를 검토하기 위하여 Hammett plot한 결과 pH 2 이하에서는 ${\Phi}$ = -0. 94, pH 4 이상에서는 ${\rho}$ = 0.54을 얻었다. pH에 따르는 반응속도 상수의 변화에 미치는 용매효과 브롬음이온효과 및 치환기효과등으로 부터 hydrazonyl bromide의 가수분해는 pH 2 이하에서는 carbonium ion 중간체를 거쳐 반응이 진행되는 $S_N1$ pH 4 이상에서는 hydrazonyl bromide에 직접 hydroxide ion이 반응하는 이른바 $S_N2$반응이 그리고 pH 2와 pH 4 사이에서는 이 두반응이 경쟁적으로 일어남을 알 수 있었다.

• 약학회지
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• 제43권6호
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• pp.789-792
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• 1999

The complete nucleotide sequence of pKH4, a small multidrug resistance (smr) plasmid isolated from multidrug resistant Staphylococcus aureus SA5, was determined. Sequence analysis has revealed that pKH4 has two open reading frames for Rep and Smr proteins. The comparison of the amino acid sequence of Smr protein of pKH4 with those of other Smr proteins of various Staphylococcus showed that Smr protein of pKH4 is a new member of the SMR family.