• Journal of Soil and Groundwater Environment
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• v.22 no.2
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• pp.41-51
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• 2017

Microbial processes that bind heavy metals and form minerals are widespread, and they represent a basic aspect of biogeochemistry. Some microorganisms can crystallize minerals by secreting a specific enzyme. In particular, calcite ($CaCO_3$) precipitation is an important part of biomineralization, and has been studied extensively because of its wide application in civil engineering technology. This process provides an effective way to stabilize heavy metals within a relatively stable crystal phase. In this study, biomineralization of calcite by three urea-hydrolyzing indigenous bacterial strains was investigated by microbiological analyses. Three bacterial strains were isolated from the sludge of B mine in Mexico and each bacterial strain was identified by the cellular fatty acid composition and 16S rRNA partial sequencing analysis. The results of the identification analysis showed that these strains were closest to Sporosarcina pasteurii, Kurthia gibsonii, and Paenibacillus polymyxa. We found that the optimum conditions for growth of these indigenous bacteria were $30-40^{\circ}C$ and pH range of 7-8. Microbiological analyses showed the possibility that the bioaccumulated heavy metals ions were deposited around the cell as crystalline carbonate minerals under the optimum conditions. The findings of our study suggest that the indigenous bacterial strains play an important role in heavy metal immobilization.

• BMB Reports
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• v.51 no.4
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• pp.188-193
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• 2018

Caffeoylserotonin (CaS), one derivative of serotonin (5-HT), is a secondary metabolite produced in pepper fruits with strong antioxidant activities. In this study, we investigated the effect of CaS on proliferation and migration of human keratinocyte HaCaT cells compared to that of 5-HT. CaS enhanced keratinocyte proliferation even under serum deficient condition. This effect of CaS was mediated by serotonin 2B receptor (5-HT2BR) related to the cell proliferation effect of 5-HT. We also confirmed that both CaS and 5-HT induced G1 progression via 5-HT2BR/ERK pathway in HaCaT cells. However, Akt pathway was additionally involved in upregulated expression levels of cyclin D1 and cyclin E induced by CaS by activating 5-HT2BR. Moreover, CaS and 5-HT induced cell migration in HaCaT cells via 5-HT2BR. However, 5-HT regulated cell migration only through ERK/AP-1/MMP9 pathway while additional Akt/NF-${\kappa}B$/MMP9 pathway was involved in the cell migration effect of CaS. These results suggest that CaS can enhance keratinocyte proliferation and migration. It might have potential as a reagent beneficial for wound closing and cell regeneration.

• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.8.1-8.8
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• 2023

Objectives: This study was designed to evaluate the parameters of bonding performance to root dentin, including push-out bond strength and dentinal tubular biomineralization, of a hydraulic bioceramic root-end filling material premixed with dimethyl sulfoxide (Endocem MTA Premixed) in comparison to a conventional powder-liquid-type cement (ProRoot MTA). Materials and Methods: The root canal of a single-rooted premolar was filled with either ProRoot MTA or Endocem MTA Premixed (n = 15). A slice of dentin was obtained from each root. Using the sliced specimen, the push-out bond strength was measured, and the failure pattern was observed under a stereomicroscope. The apical segment was divided into halves; the split surface was observed under a scanning electron microscope, and intratubular biomineralization was examined by observing the precipitates formed in the dentinal tubule. Then, the chemical characteristics of the precipitates were evaluated with energy-dispersive X-ray spectroscopic (EDS) analysis. The data were analyzed using the Student's t-test followed by the Mann-Whitney U test (p < 0.05). Results: No significant difference was found between the 2 tested groups in push-out bond strength, and cohesive failure was the predominant failure type. In both groups, flake-shaped precipitates were observed along dentinal tubules. The EDS analysis indicated that the mass percentage of calcium and phosphorus in the precipitate was similar to that found in hydroxyapatite. Conclusions: Regarding bonding to root dentin, Endocem MTA Premixed may have potential for use as an acceptable root-end filling material.

• Journal of Magnetics
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• v.21 no.1
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• pp.20-24
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• 2016

Magnetic properties of bio-magnetic molecule ferritin have been investigated. Two ferritin samples were synthesized under different magnetic fields, 0 and 9.4 T, respectively. This work is focused on the influence of magnetic field on biomineralization process. While magnetization vs. temperature (M-T) data of both samples measured at 1000 Oe are almost identical except for low temperature region (T < 6 K), magnetization vs. field (M-H) data show noticeable difference. From an analysis of M-H data by using a modified Langevin function, we could extract the saturation magnetization $m_0$(T), the effective magnetic moment ${\mu}_{eff}$(T) and the linear susceptibility x(T). The difference between the samples is most prominent in the x(T), whereby the x(T) of the sample prepared at 9.4 T is 1.7 times bigger than that of the other. In addition, from hysteresis and relaxation measurements, we found the sample prepared at 9.4 T showed strikingly smaller coercivity and slower relaxation.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.191-196
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• 2017

Transglutaminase2 (TGM2) is a multi-functional calcium dependent enzyme that affects angiogenesis, apoptosis, differentiation, attachment, and changes in the extracellular matrix. However, its function in periodontal tissue has not yet been studied. The aim of this study was to investigate the association of the TGM2 expression and the modulation of inflammatory mediators in inflamed periodontal ligament (PDL) cells induced by pro-inflammatory cytokines such as Interleukin-$1{\beta}$ and the Tumor necrosis $factor-{\alpha}$. The expression of TGM2 was increased in the inflamed periodontal tissue and PDL cells. Over-expressed TGM2 in the PDL cells increased expression of MMP1, MMP3, IL-6, CXCL8, and PTGS2. Conversely, inhibition of TGM2 activity using LDN27219, a TGM2 inhibitor, resulted in decreased expression of MMP1, MMP3, IL-6, and CXCL8. The mRNA expression was confirmed by RT-PCR and quantified by qRT-PCR. Protein levels were also confirmed by immunofluoroscence staining. These results suggest that TGM2 plays an important role in the regulation of inflammatory mediators which exacerbate tissue damage in inflamed periodontal tissue.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1322-1332
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• 2019

In this paper, we systematically investigated the influence of some selected ligands on the U-phosphate precipitation induced by soil bacteria. These organics are widely ranging from acetate, lactate, salicylate and citrate to oxalate. The results revealed that uranium could be biomineralized on bacteria as $UO_2HPO_4{\cdot}4H_2O$ or $(UO_2)_3(PO_4)_2{\cdot}4H_2O$. The influence of organic ligands on the biomineralization had clear-cut correlations with its complexation abilities to uranyl. It was clearly found that the U-phosphate biomineralization was affected noticeably by the strong ligands (oxalate and citrate). Further study discovered that when the organic ligands were uncompetitive with biotic $PO_4^{3-}$ for uranyl, the transformation of uranyl species from ${\beta}-UO_2(OH)_2$ colloidal particles to free $UO_2^{2+}$-ligands ions could facilitate the U-phosphate biomineralization. However, when the organic ligands competed with biotic $PO_4^{3-}$ for uranyl, the U-phosphate biomineralization were inhibited. Our results highlight the importance of complex interactions of strong organic ligands with uranyl during the bacterial precipitation of U-P compounds and thus for the mobilization and immobilization of radio-nuclides in the nature.

• 한국전자현미경학회:학술대회논문집
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• 1997.05a
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• pp.65-68
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• 1997

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.223-228
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• 2011

To understand the role of hemocytes in the shell repair process, a hole was drilled in the right valves of the Pacific oyster, Crassostrea gigas, and the repair process was observed. Histological observations suggested that the exterior surface of the shell was repaired by aggregated hemocytes. The nuclei of the hemocytes were cleary stained in the regenerated shell while appearing fragmented after calcification at the $7^{th}$ day. Globular calcium granules were genegenerated from the hemocytic monolyer after 6 days of incubation which were morphologically and chemically identical with those from prismatic shell. Our finding suggested that the repaired prismatic shell was composed by aggregated hemocytes and that their endogenous calcium component might support the nucleation of calcium biomineralization during shell repair.

• International Journal of Oral Biology
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• v.39 no.3
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• pp.145-151
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• 2014

During bone remodeling, there is requirement of differentiation of osteoblastic cells. Previously, we identified proteins differentially expressed in soft tissue during bone healing. Of these proteins, we focused the effect of LTF on differentiation of osteoblast. In order to analyze the osteogenic ability of LTF, we treated conditioned media collected from human LTF-stably transfected HEK293T cells into osteoblastic MC3T3-E1. The results showed that the activity and expression of alkaline phosphatase were increased in MC3T3-E1 cells treated with conditioned media containing LTF in dose- and time-dependent manner. At the same time, we observed the significant increase of the expression of osteoblastic genes, such as ALP, BSP, COL1A1, and OCN, and along with matrix mineralization genes, such as DMP1 and DMP2, in LTF conditioned media-treated groups. Moreover, the result of treating recombinant human LTF directly into osteoblastic MC3T3-E1 showed the same pattern of treating conditioned media containing LTF. Our study demonstrated that LTF constitutively enhances osteoblastic differentiation via induction of osteoblastic genes and activation of matrix mineralization in MC3T3-E1 cells.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.213-219
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• 2009

Crystallization experiments were performed by addition of various amino acids into biomineralization mixture of calcium carbonate. Liquid-liquid reaction of calcium carbonate was investigated by mixing calcium chloride, sodium carbonate and additives such as silk fibroin, asparagine, aspartic acid, glutamic acid and glycine. Also, the effects of reaction time, pH and solution concentration were observed. Analysis of crystals was done by FE-SEM, XRD, FT-IR equipments. FE-SEM was used in order to analyze morphology and crystal size. XRD was used to measure peak intensities and presence of $CaCO_3$ crystal. Two kinds of crystals were confirmed by FT-IR spectrum. Crystal distribution with reaction time was identified with measured peak areas of XRD and FT-IR data.