• Journal of Microbiology and Biotechnology
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• 제27권4호
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• pp.844-855
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• 2017

Phosphate-solubilizing bacteria (PSB) have the ability to dissolve insoluble phosphate and enhance soil fertility. However, the growth and mineral phosphate solubilization of PSB could be affected by exogenous soluble phosphate and the mechanism has not been fully understood. In the present study, the growth and mineral phosphate-solubilizing characteristics of PSB strain Burkholderia multivorans WS-FJ9 were investigated at six levels of exogenous soluble phosphate (0, 0.5, 1, 5, 10, and 20 mM). The WS-FJ9 strain showed better growth at high levels of soluble phosphate. The phosphate-solubilizing activity of WS-FJ9 was reduced as the soluble phosphate concentration increased, as well as the production of pyruvic acid. Transcriptome profiling of WS-FJ9 at three levels of exogenous soluble phosphate (0, 5, and 20 mM) identified 446 differentially expressed genes, among which 44 genes were continuously up-regulated when soluble phosphate concentration was increased and 81 genes were continuously down-regulated. Some genes related to cell growth were continuously up-regulated, which would account for the better growth of WS-FJ9 at high levels of soluble phosphate. Genes involved in glucose metabolism, including glycerate kinase, 2-oxoglutarate dehydrogenase, and sugar ABC-type transporter, were continuously down-regulated, which indicates that metabolic channeling of glucose towards the phosphorylative pathway was negatively regulated by soluble phosphate. These findings represent an important first step in understanding the molecular mechanisms of soluble phosphate effects on the growth and mineral phosphate solubilization of PSB.

• 한국환경농학회지
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• 제26권1호
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• pp.36-41
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• 2007

PDA-calcium phosphate 평판배지를 이용하여 경상남북도 일대의 토양으로부터 인산가용화능이 우수한 사상균을 분리하고 배양특성을 조사하였다. 최종적으로 분리한 인산가용화능이 우수한 사상균 PS-104 균주를 선발하여 형태적 특성을 조사한 결과 이 균주의 분생자는 비가지형으로 끝이 돌출되어 있으며, 균사가 격막으로 형성되는 등의 특징을 갖는 Aspergillus sp. PS-104 균주로 동정되었다. 이 균주의 인광석 분해능이 최대가 되는 최적 배양온도와 pH는 각각 $30^{\circ}C$와 pH 7.0이었다. 이와 같은 배양조건에서 tricalcium phosphate, aluminium phosphate, hydroxyapatite, 인광석 등의 난용성 인산염에 대한 이 균주의 인산가용화능을 살펴보면 최대 인산가용화능은 tricalcium-phosphate 처리구(1,900 ppm)에서, 최소 인산가용화능은 hydroxyapatite 처리구(320 ppm)에서 확인되었다. 또한 이 균주의 인산가용화능은 질소원으로 첨가한 ammonium 염보다 nitrate 염에서 높게 나타났다.

• 공업화학
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• 제3권4호
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• pp.670-677
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• 1992

2, 3-Dibromopropyl alcohol과 chlorophenyl phosphate로 부터 (2, 3-dibromopropyl)phenyl phosphate[DPP]를 합성하고, 또한 DPP에 n-octadecyl chloride를 가하여 (2,3-dibromopropyl)phenyl octadecyl phosphate[DPOP]를 합성하였다. DPP와 DPOP에 각각 유화제를 블렌딩시켜 난연제 DPPF와 DPOPF를 제조하였는데, 모두 o/w(oil in water)유화형 난연제였다. 이 2종류의 난연제를 각종 합성직물에 처리하여 난연성과 인열강도를 측정한 결과 DPPF는 난연성만이, 그리고 DPOPF는 난연성과 유연성 모두 양호하였다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.592-593
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• 2003

I. Objectives The purpose of this study was to compare in vivo the biocompatibility of new calcium phosphate-based root canal sealers(CAPSEAL I, CAPSEAL II) with another type of commercially available calcium phosphate sealer (Apatite Root Sealer type I, Apatite Root Sealer type II) and zinc oxide-eugenol-based sealer (Pulp Canal Sealer EWT) after implantaion in rat subcutaneous tissue. II. Materials and Methods 64 Sprague-Dawley rats were used. There were five groups of three animals each for experimental period of 1, 2, 4, and 12 weeks. The teflon tubes, 5mm in length with an inner diameter of 1.5mm, were washed with ethanol and distilled weter and autoclaved.(omitted)

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.244-252
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• 2007

Escherichia coli has a PhoR-PhoB two-component regulatory system to detect and respond to the changes of environmental phosphate concentration. For the E. coli W3110 strain growing under phosphate-limiting condition, the changes of global gene expression levels were investigated by using DNA microarray analysis. The expression levels of some genes that are involved in phosphate metabolism were increased as phosphate became limited, whereas those of the genes involved in ribosomal protein or amino acid metabolism were decreased, owing to the stationary phase response. The upregulated genes could be divided into temporarily and permanently inducible genes by phosphate starvation. At the peak point showing the highest expression levels of the phoB and phoR genes under phosphate-limiting condition, the phoB- and/or phoR-dependent regulatory mechanisms were investigated in detail by comparing the gene expression levels among the wild-type and phoB and/or phoR mutant strains. Overall, the phoB mutation was epistatic over the phoR mutation. It was found that PhoBR and PhoB were responsible for the upregulation of the phosphonate or glycerol phosphate metabolism and high-affinity phosphate transport system, respectively. These results show the complex regulation by the PhoR-PhoB two-component regulatory system in E. coli.

• 방사선산업학회지
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• 제3권1호
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• pp.39-45
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• 2009

Three mineral phosphate solubilizing (MPS) bacteria where isolated from rhizosphere soil samples of common bean and weed plants. 16S rDNA analysis indicated that the isolate P2 and P3 are closely related to Pantoea dispersa while isolate P4 is closely related to Pantoea terrae. Isolates P2 and P3 recorded $381.60{\mu}g\;ml^{-1}$ and $356.27{\mu}g\;ml^{-1}$ of tricalcium phosphate (TCP) solubilization respectively on 3 days incubation. Isolate P4 recorded the TCP solubilization of $215.85{\mu}g\;ml^{-1}$ and the pH was dropped to 4.44 on 24 h incubation. Further incubation of P4 sharply decreased the available phosphorous to $28.94{\mu}g\;ml^{-1}$ and pH level was raised to 6.32. Gamma radiation induced mutagenesis was carried out at $LD_{99}$ dose of the wild type strains. The total of 14 mutant clones with enhanced MPS activity and 4 clones with decreased activity were selected based on solubilization index (SI) and phosphate solubilization assay. Mutant P2-M1 recorded the highest P-solubilizing potential among any other wild or mutant clones by releasing $504.21{\mu}g\;ml^{-1}$ of phosphorous i.e. 35% higher than its wild type by the end of day 5. A comparative evaluation of TCP solubilization by wild type isolates of Pantoea and their mutants, led to select three MPS mutant clones such as P2-M1, P3-M2 and P3-M4 with a potential to release >$471.67{\mu}g\;ml^{-1}$ of phosphorous from TCP. These over expressing mutant clones are considered as suitable candidates for biofertilization.

• 상하수도학회지
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• 제32권3호
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• pp.253-259
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• 2018

Cu(II) can cause health problem for human being and phosphate is a key pollutant induces eutrophication in rivers and ponds. To remove of Cu(II) and phosphate from solution, chitosan as adsorbent was chosen and used as a form of hydrogel bead. Due to the chemical instability of hydrogel chitosan bead (HCB), the crosslinked HCB by glutaraldehyde (GA) was prepared (HCB-G). HCB-G maintained the spherical bead type at 1% HCl without a loss of chitosan. A variety of batch experiment tests were carried out to determine the removal efficiency (%), maximum uptake (Q, mg/g), and reaction rate. In the single presence of Cu(II) or phosphate, the removal efficiency was obtained to 17 and 16%, respectively. However, the removal efficiency of Cu(II) and phosphate was increased to 50~55% at a mixed solution. The maximum uptake (Q) for Cu(II) and phosphate was enhanced from 11.3 to74.4 mg/g and from 3.34 to 36.6 mg/g, respectively. While the reaction rate of Cu(II) and phosphate was almost finished within 24 and 6 h at single solution, it was not changed for Cu(II) but was retarded for phosphate at mixed solution.

• 미생물학회지
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• 제23권2호
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• pp.90-100
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• 1985

The present study was designed to investigate cellular regulation of phosphate metabolism between catabolically repressed and derepressed states in yeast (Saccharomyces uvarum). The activities of various phospatases and the contents of phosphate compounds were detected according to the culture phase and various phosphate concentrations. As the results, Saccharomyces uvarum derepressed many phosphate metabolizing enzymes such as alkaline phosphatase, acid phosphatase and ATPase more than ten fold simultaneously during catabolic repression (phospgate and sugar starvation). At the same state, the amounts of orthophosphate, nucleotidic labile phosphate and acid soluble polypgosphate were increased, compared to basal levels of normally cultivated cells. $Mg^{++}-stimulated$ type among all phospatases was appeared to have most of the enzyme activity. It could be postulated that $K^+ -stimulated$ alkaline phosphatase was directly or indirectly correlated with the synthesis of acid insoluble polyphosphate $Mg^{++}-stimulated$ phosphatase with the degradation of polyphosphates. In case of cultivation in the medium supplemented with sugar and phosphate (catabolic derepression), phospgatase activities except for alkaline phosphatase were decreased rapidly through the progressive batch culture, After 12 hrs culture, at early exponential phase, the cellular accumulation of acid insoluble polyphosphate increased about 5 fold, compared to those of the starved cells. Under catabolic repression, it could be postulated that intracellular phosphate metabolism was regulated by derepressions of phosphatases. The function of polyphosphate system was shown to compensate the ATP/ADP system as phosphate donor and energy source especially during catabolic repression.

• 한국미생물·생명공학회지
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• 제17권1호
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• pp.46-50
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• 1989

최소 생산배지에 포함된 25mM 이상의 무기인(Inorganic phosphate)은 Cephalosporium acremonium의 생육은 증대시켰으나, cephalosporin C(CPC) 생산은 감소시켰다. Phosphate-starved 휴지세포계를 이용하여 균체내의 ATP, ADP와 AMP를 측정하였다. 그 결과로부터 무기인은 adenylated nucleotide의 농도의 비율로 표시되는 energy charge를 조절하여 CPC 생산성에 영향을 주는 것으로 밝혀졌다. 또한, 무기인에 의한 CPC 생합성은 repression 효과에 의한 것이 아니라 inhibition 효과에 의해 조절받는 것을 알 수 있었다.

• 한국토양비료학회지
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• 제40권5호
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• pp.405-411
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• 2007

본 연구는 감귤원 토양유형별로 고정되어 있는 난용성 인산염함량을 파악하고 이를 생물학적으로 이용하고자 인산가용화 우수미생물을 선발하여 특성을 조사하였다. 토양중 난용성 인산염의 형태별 분포는 Al-P>Ca-P>Fe-P 순으로 화산회토 토양이 비화산회토 보다 많았다. PDA-P배지를 이용하여 인산염 가용화능이 우수한 Bacillus sphaericus를 분리하였으며 pH 4~5와 $30^{\circ}C$에서 생육이 제일 좋았다. Bacillus sphaericus은 $AlPO_4$에서 324.5 ppm, $Ca_{10}(PO_4)_6(OH)_2$에서 334.8 ppm, $Ca_3(PO_4)_2$에서 207.0 ppm의 유리인산을 생성하였으며 인산효소활성은 $35^{\circ}C$에서 배양할 때 높았다. Bacillus sphaericus를 Bentonite 등 담체에 고정 후 온도를 달리하여 7개월 보존기간 동안 밀도변화를 조사한 결과 $10^5c.f.u.\;g^{-1}$ 수준과 인산가용화능을 유지하여 추후 생물비료로 이용이 가능할 것으로 기대된다.