• Title/Summary/Keyword: mechanisms

Search Result 13,273, Processing Time 0.051 seconds

Individual Brand Loyalty and the Self-Corporate Connection Induced by Corporate Associations (기업연상이 소비자의 자아연관성과 개별브랜드의 충성도에 미치는 영향)

  • Choi, Nak-Hwan;Park, Deok-Su
    • Journal of Distribution Science
    • /
    • v.9 no.1
    • /
    • pp.5-15
    • /
    • 2011
  • Research regarding corporate associations in marketing has generally been approached using the association theory. However, limited research investigates the effect of corporate associations on consumer loyalty to individual brands by examining the role of self connectedness with a corporate image. The activation of behavior-related constructs can influence individuals' behaviors without their intention or conscious awareness. A recently developed body of research suggests that self connection can play an important role in affecting subsequent behaviors. Although these effects have received considerable attention, the set of mechanisms involved in self connectedness and loyalty to individual brands is not clear. An active self account in which associative constructs can affect behavior by temporarily altering the active self-concept may lead to behavior or evaluation. If the exposure to a corporate brand can induce consumers' cognitive associations and goal-primed effects through the role of active self accounting, the connectedness between the consumer's self and the corporate brand could be developed and this connectedness could be explained by associative and connection models and the goal priming theory. Therefore, this study investigates the influence of corporate associations on loyalty to individual brands through connections between the corporate and the consumer's self. There are three main purposes of the research. First, theories regarding corporate associations will be explored. Second, theories of self-concept will be investigated and self connectedness with corporate brands will be explored. Third, the effects of the connectedness between the self and the corporation on corporate identification and loyalty to individual brands will be investigated. For the purposes of this research, the types of corporate associations are classified into corporate ability (CA) associations and corporate social responsibility (CSR) associations. Furthermore, the connectedness between the consumer's self and the corporate image are divided into two concepts: the connectedness between the individual self-concept and the corporate identity and the connectedness between social self-concept and the corporate identity. This study suggests the hypotheses that the types of consumer self connections with the corporate image could vary according to the types of corporate associations created and further that the connectedness between the corporate association and the consumer's self-concept have positive effects on loyalty to corporate individual brands. The results of testing these hypotheses are as follows. First, corporate ability associations enhance the connectedness between the consumer's individual self and corporate brands. That is, corporate ability associations influence individual connectedness between the corporate and individual self-concept positively from the viewpoint of the consumer's personal ability and branding success. In addition, corporate social responsibility associations have a positive effect on social connectedness between the corporation and the consumer's social self-concept. Second, the connectedness between the corporate brand and the consumer's self-concept affects identification with the corporation. The consumer's personal self and social self connectedness induces corporate identification. Third, individual self connectedness has a positive effect on loyalty to corporate individual brands, while social self connectedness does not. This also means that individual self connectedness with the corporate image or brand plays a more important role in forming individual brand loyalty than social self connectedness with the corporate does. In addition, social connectedness cannot influence individual brand loyalty until it passes through identification with the corporate. Fourth, consumers who experience identification with a corporate identity also show positive responses to corporate individual brands. That is, consumers also develop loyalties toward individual brands through the corporate identification because self-pursued goals that are induced by corporate associations can be achieved by consuming the individual brands that are sold by the corporate that the consumers identify with.

  • PDF

Repetition of Apoptosis Induced by Amiloride Derivatives in Human Umbilical Vein Endothelial Cells (제대정맥 내피세포에서 Amiloride 유도체에 의한 Apoptosis 반복)

  • Park, Kyu Chang;Park, Kyu Sang;Moon, Soo Jee
    • Clinical and Experimental Pediatrics
    • /
    • v.46 no.1
    • /
    • pp.56-66
    • /
    • 2003
  • Purpose : Human umbilical vein endothelial cells(HUVECs) play an important role in regulating blood flow by releasing vasoactive substances. It has been reported that endothelial impairment and dysfunction might be a primary cause of placental vascular disease, which is manifested clinically as preeclampsia in mother and intrauterine growth restriction in fetus. Furthermore, the frequency of apoptotic changes is increased in umbilical and placental tissues from growth-restricted pregnancies. However, the various mechanisms of umbilical endothelial cell apoptosis have not been broadly proposed. We investigate the effects of amiloride derivatives on apoptotic death of HUVECs and identify their ionic mechanism. Methods : HUVECs were purchased from Clonetics, and cultured on endothelial cell growth medium. MTT assay and flow cytometry were used for assessing cytotoxic effect and confirming the apoptosis. Changes in intracellular ion concentrations were measured with specific fluorescent dyes and fluorescence imaging analysis system. Results : Amiloride derivatives elicited cytotoxic effects on HUVECs with dose-dependent manners and the rank order of potency is HMA($IC_{50}\;11.2{\mu}M$), MIA>EIPA>>amiloride. HMA-induced cytotoxicity is dependent on extra- and intracellular pH, that is, increase extra- and intracellular pH augmented the cytotoxic effects of HMA. HMA dose-dependently reduced intracellular major ions, such as $K^+$ and $Cl^-$. Interestingly, the depletion of intracellular ions induced by HMA was also significantly enhanced at alkaline extracellular pH. Conclusion : Amiloride derivatives induce apoptosis of HUVECs with dose and pH dependent manners. They reduce intracellular $K^+$ and $Cl^-$ concentration, which is also extracellular pH dependent.

Clinical factors causing hyponatremia in patients with mucocutaneous lymph node syndrome (가와사끼병에서 저나트륨혈증의 관련인자에 대한 임상적 고찰)

  • Kim, Soo Yeon;Kim, Hyun Jung;Choi, Jun Seok;Huh, Jae Kyung
    • Clinical and Experimental Pediatrics
    • /
    • v.52 no.3
    • /
    • pp.364-369
    • /
    • 2009
  • Purpose : Clinical and laboratory findings predict a severe outcome for mucocutaneous lymph node syndrome. This study aimed to define the clinical characteristics of Kawasaki disease (KD) patients with hyponatremia and to determine the factors associated with its development. Methods : Retrospective studies were performed on 114 KD patients who received an initial high-dose intravenous immunoglobulin (IVIG, single 2 g/kg/dose) within 10 days of fever onset from January 2006 to February 2008. These patients were divided into 2 groups. Group 1 consisted of 30 (26.3%) patients with hyponatremia, and group 2 consisted of 84 (73.6%) patients without hyponatremia. Clinical manifestations, laboratory results, and echocardiographic findings were compared between the groups. Results : Group 1 patients were more likely to have a coronary artery lesion (53.3% versus 20.2%, P=0.005) and suffered from diarrhea (41.3% versus 14.1%, P=0.007). There was a higher incidence of cardiovascular involvement in group 1 patients, including coronary dilatation (46.6%), valvular regurgitation (13.3%), pericardial effusion (6.7%) and medium-sized aneurysm (6.7%). There were no coronary aneurysms in group 2 patients. Serum C-reactive protein (CRP) was significantly higher in patients with hyponatremia ($12.2{\pm}7.79$ mg/dL versus $7.3{\pm}4.7$ mg/dL, P=0.003) and IVIG-resistant patients were more common in group 1 (13.3% versus 3.6%). Conclusion : These results indicate that hyponatremia in KD occurs in patients exhibiting severe inflammation and was significantly associated with the development of coronary disease. Further studies will be necessary to confirm the pathogenic mechanisms of hyponatremia in KD patients.

IL-12 Regulates B7-H1 Expression in Ovarian Cancer-associated Macrophages by Effects on NF-κB Signalling

  • Xiong, Hai-Yu;Ma, Ting-Ting;Wu, Bi-Tao;Lin, Yan;Tu, Zhi-Guang
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.15 no.14
    • /
    • pp.5767-5772
    • /
    • 2014
  • Background and Aim: B7-H1, a co-inhibitory molecule of the B7 family, is found aberrantly expressed in ovarian cancer cells and infiltrating macrophage/dendritic-like cells, and plays a critical role in immune evasion by ovarian cancer. IL-12, an inducer of Th1 cell development, exerts immunomodulatory effects on ovarian cancer. However, whether IL-12 regulates B7-H1 expression in human ovarian cancer associated-macrophages has not been clarified. Therefore, we investigated the effects of IL-12 on the expression of B7-H1 in ovarian cancer-associated macrophages and possible mechanisms. Methods: PMA induced THP-1-derived macrophages or human monocyte-derived macrophages were treated with recombinant IL-12 (rIL-12) or infected with adenovirus carrying human IL-12 gene (Ad-IL-12-GFP) for 24 h, then cocultured with the SKOV3 ovarian cancer cell line for another 24 h. Macrophages were collected for real-time PCR and Western blot to detect the expression of B7-H1, and activation of the NF-${\kappa}B$ signaling pathway. Moreover, supernatants were collected to assay for IL-12, IFN-${\gamma}$ and IL-10 by ELISA. In addition, monocyte-derived macrophages treated with IFN-${\gamma}$ were cocultured with SKOV3 and determined for the expression of B7-H1. Furthermore, the expression of B7-H1 in monocyte-derived macrophages was also evaluated after blocking NF-${\kappa}B$ signaling. Results: The expression of B7-H1 was significantly upregulated in monocyte-derived macrophages treated with rIL-12 or Ad-IL-12-GFP compared with the control groups (p<0.05), accompanied by a remarkable upregulation of IFN-${\gamma}$ (p<0.05), a marked downregulation of IL-10 (p<0.05) and activation of NF-${\kappa}B$ signaling. However, the upregulation of B7-H1 was inhibited by blocking the NF-${\kappa}B$ signaling pathway (p<0.05). Expression of B7-H1 was also increased (p<0.05) in monocyte-derived macrophages treated with IFN-${\gamma}$ and cocultured with SKOV3. By contrast, the expression of B7-H1 in THP-1-derived macrophages was significantly decreased when treated in the same way as monocyte-derived macrophages (p<0.05), and IL-10 was also significantly decreased but IFN-${\gamma}$ was almost absent. Conclusions: IL-12 upregulates the expression of B7-H1 in monocyte-derived macrophages, which is possible though inducing the secretion of IFN-${\gamma}$ and further activating the NF-${\kappa}B$ signal pathway. However, IL-12 downregulates the expression of B7-H1 in THP-1-derived macrophages, associated with a lack of IFN-${\gamma}$ and inhibition of expression of IL-10.

A Study on Mapping Relations between eBook Contents for Conversion (전자책 문서 변환을 위한 컨텐츠 대응 관계에 관한 연구)

  • 고승규;임순범;김성혁;최윤철
    • The Journal of Society for e-Business Studies
    • /
    • v.8 no.2
    • /
    • pp.99-111
    • /
    • 2003
  • By virtue of diverse advantages derived from digital media, eBook is getting started to use. And many market research agencies have predicted that its market will be greatly expanded soon. But against those expectations, copyright-related problems and the difficulties of its accessing inherited from various eBook content formats become an obstacle to its diffusion. The first problems can be solved by DRM technology. And to solve the second problems, each nation has published its own content standard format. But the domestic standards are useful only the domestic level, they still leave the problems in the national level. The variety of content formats has created a demand for mechanisms that allow the exchange of eBook contents. Therefore we study the mapping relations between eBook contents for conversion. To define the mapping relations, first we extract the mapping both between eBook contents and between normal XML documents. From those mappings, we define seven mapping relations and classify them by cardinality. And we analyze the classified relations, which can be generated by automatic, or not. Using these results, we also classify the eBook content conversion as automatic, semi-automatic, and manual. Besides, we provide the conversion templates for mapping relations for automatic generation of conversion scripts. To show the feasibility of conversion templates, we apply them to the eBook content conversion. Experiment shows that our conversion templates generate the conversion scripts properly. We expected that defined mapping relations and conversion templates can be used not only in eBook content conversion , but also in normal XML document conversion.

  • PDF

A Study on The Content of Liver Protein, Nucleic Acids, and Guanine Deaminase Activity of Mouse During Acute Starvation (급성(急性) 기아(饑餓)마우스의 간단백질(肝蛋白質), 핵산(核酸) 및 Guanine Deaminase 활성(活性)에 관(關)한 연구(硏究))

  • Park, Seung-Hee;Kim, Seung-Won
    • Journal of Nutrition and Health
    • /
    • v.1 no.2
    • /
    • pp.107-115
    • /
    • 1968
  • Number of aspects, not only nutritional but social as well as political involved in human starvation pose nowadays global problems. In order to help establish the minimum nutritional requirements in the daily life of a man and to free people as well from either undernourishment, malnutrition or even starvation many workers have devoted themselves so far on the research programs to know what and how number of metabolic events take place in animals in vivo. It is the purpose of the present paper to examine in effect to what extent both of the protein and nucleic acids (DNA & RNA) together with an enzyme, guanine deaminase, which converts guanine into xanthine and in turn ends up to uric acid as an end product, undergo changes, quantitatively during acute starvation, using the mouse as an experimental animal. The mouse was strictly inhibited from taking foods except drinking water ad libitum and was sacriflced 24, 48, and 72 hours following starvation thus acutely induced. The animals consisted of two experimental groups, one control and another starvation groups, each being consisted of 6-24 mice of whose body weights ranged in the vicinity of 10 g. The animals were sacriflced by a blow on the head, followed by immediate excision of their livers into ice-cold distilled water, washing adherent blood and other contaminant tissues. The liver was minced foramin, by an all-glass homogenizer immersing it in an ice-bath, followed by subsequent fractionatin of the homogenate (10% W/V in 0.25M sucrose solution made up with 0.05M phosphate buffer of pH 7.4). For the liver protein and guanine deaminase assay, the 10% homogenate was centrifuged at 600 x g for 10 minutes to eliminate the nuclear fraction; and for the estimation of DNA and RNA, the homogenate was prepared by the addition of 10% trichloroacetic acid in order to free the homogenate from the acid-soluble fraction, the remaining residue being delipidate by the addition of alcohol and dried in vacuo for later KOH (IN) hydrolysis. The changes in body and liver wegihts during acute starvation were checked gravimetrically. Protein contents in the liver were monitored by the method of Lowry et al; and guanine deaminase activities were followed by the assay of liberated ammonia from the substrate utilizing the Caraway's colorimetry. The extraction of both DNA and RNA was performed by the Schmidt-Thannhauser's method, which was followed by Marmur's method of purification for DNA and by Chargaff's method of purification for RNA. The determinations of both DNA and RNA were carried out by the diphenylamine reaction for the former and by the orcinol reaction for the latter. The following resume was the results of the present work. 1. It was observed that the body as well as liver weights fall abruptly during starvation, and that the loss of body weight showed no statistical correlation with the decreases in the content of liver protein. 2. The content of liver protein and activity of liver guanine deaminase activity as well decline dramatically, and the specific activities of the enzyme (activity/protein), however, decreased gradually as starvation proceeded. 3. Both of the nucleic acids, DNA and RNA, showed decrements in the liver of mouse during acute starvation; the latter, however, being more striking in the decline as compared to the former. 4. The decreases in the liver protein content as resulted from the acute starvation had no statistically significant correlation with the decrements of DNA in the same tissue, but had regressed with a significant statistical correlation with the fall of RNA in the tissue. 5. The decrease in the activity of guanine deaminase in the liver of mouse during acute starvation was functionally more proportional to the decrease in RNA than DNA, and moreover correlated with the changes in the content of the liver protein. 6. The possible mechanisms involved during in this acute starvation as bring the decreases in the contents of DNA, protein, and guanine deaminase were discussed briefly.

  • PDF

The Effect of Risperidone on Serum Prolactin Concentrations (Risperidone이 혈청 Prolactin 농도에 미치는 영향)

  • Cheon, Jin-Sook;Cho, Woong;Oh, Byoung-Hoon
    • Korean Journal of Biological Psychiatry
    • /
    • v.5 no.2
    • /
    • pp.253-262
    • /
    • 1998
  • Objectives : Risperidone, an atypical antipsychitics which blocks both dopaminergic and serotonergic receptors, have a good response to the negative symptoms as well as positive symptoms, and improve cognitive dysfunction of schizophrenic patients. Furthermore, it has few extrapyramidal side effects and tardive dyskinesia. Although it had been reported that the atypical antipsychotics have less effect on prolactin(PRL) than the classical antipsychotics, we could experience PRL-associated symptoms such as amenorrhea, galactorrhea and hyperprolactinemia in practice. Therefore, we tried to identify the sex differences of risperidone-induced hyperprolactinemia, to evaluate factors affecting PRL levels, and to know the association between cognitive disorders and PRL. Methods : The baseline levels of PRL and TSH prior to risperidone administration were measured by enzyme immunoassay method for 50 patients(25 ma-les and 25 females) admitted with schizophrenia, schizoaffective disorder or schizophreniform disorder according to the DSM-IV classification, and the measurements of PRL were repeated on the 2nd and the 4th wks of risperidone administration. Concomitantly, the severity of psychotic symptoms using CGI, BPRS and PANSS, and the cognitive dysfunction using PANSS-CF were assessed prior to, on the 2nd and the 4th wks of risperidone administration. The PRL and TSH levels of 54 healthy controls(29 males and 25 females) who had no medical, neurological and psychiatric illnesses were also evaluated. Furthermore, the correlation with the psychiatric diagnosis, education, age, sex, duration of illnesses, risperidone dosage, duration of risperdone administration, TSH concentration, cognitive function, severity of psychotic symptoms were also identified. Results : 1) The baseline PRL levels of female schizophrenics($74.3{\pm}49.6ng/ml$) were significantly(p<0.005) higher than those of males($36.3{\pm}24.6ng/ml$), which were significantly(p<0.0001 respectively) higher than those of controls(females $16.9{\pm}6.1ng/ml$, males $13.3{\pm}4.9ng/ml$). The PRL levels measured on the 2nd wks(females $133.7{\pm}47.8ng/ml$, males $56.9{\pm}23.6ng/ml$) and on the 4th wks(females $146.1{\pm}45.9ng/ml$, males $70.0{\pm}31.5ng/ml$) after risperidone administration were significantly(p<0.0001 respectively) higher in females. The mean dosages of risperidone on the 2nd wks were $3.8{\pm}1.7mg$(2-6mg) for the females and $4.0{\pm}1.6mg$(2-6mg) for the males, and on the 4th wks were $4.5{\pm}2.1mg$(2-8mg) for the females and $5.4{\pm}2.2mg$(2-8mg) for the males. 2) The rise of PRL levels were positively correlated with increased risperidone dosage in males(${\gamma}$=0.307 on the 2nd wks and ${\gamma}$=0.280 on the 4th wks), while they were not correlated with dosages in females. For the females, the PRL levels were negatively correlated(${\gamma}$=-0.320) with decrease of TSH concentration. The baseline PRL levels were not correlated with age, education, duration of illnesses, psychopathology, cognitive disorders in both males and females, while it was negatively correlated with TSH levels only in females(${\gamma}$=-0.320). 3) The cognitive dysfunction was not correlated with PRL levels in males, while PANSS-CF scores were negatively correlated with PRL levels(${\gamma}$=-0.220 on the 2nd wks and ${\gamma}$=-0.366 on the 4th wks) in females. The psychopathology was positively correlated with cognitive dysfunction in both males and females. Therefore, the risperidone-induced cognitive improvement seemed to be correlated with improvement of psychopathology in both males and females, and with increase in PRL levels only in females. Conclusions : The fact that the serum PRL levels of schizophrenics were higher than those of controls, especially in females suggested that it could be related with risperidone dosage in males and with primary pathological process in females. The risperidone-associated cognitive improvement seemed to be related with general improvement of psychopathology as well as the rise of PRL levels especially in females. The facts that the effect of risperidoneinduced hyperprolactinemia and the cognitive function were more in females suggested that somewhat different mechanisms could be exerted on them.

  • PDF

A Study on the Effect of Chinese University Students' Entrepreneurial Intention: Focused on the Mediating Effect of Entrepreneurial Attitude and Perceived Behavioral Control (중국 대학생들의 창업 의도에 미치는 영향에 관한 연구: 창업 태도와 인지된 행동 통제의 매개효과를 중심으로)

  • Xiu, Shi;Oh, Keun Yeob;Kim, Hyung Jun;Min, Taeki
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.15 no.3
    • /
    • pp.175-189
    • /
    • 2020
  • While there have been many previous studies showing that an entrepreneur's personal characteristics have a significant impact on his intention to start a business, there was relatively little research on the inherent mechanisms for this. Recent researches show that entrepreneur's personal characteristics affect the entrepreneurial intention through entrepreneurial attitude and perceived behavioral control, rather than directly. This study carried out empirical research on 233 Chinese university students on what personal characteristics affect the entrepreneurial intention of Chinese university students, who are actively engaged in start-up activities recently. Based on the theory of planned behavior, we set entrepreneurial attitude and perceived behavioral control as important variables that shape the entrepreneurial intention and formed a model and hypotheses that personal characteristics of a potential entrepreneur(leadership, planning, innovation, sociality) affect the entrepreneurial intention through these two variables. We verified these hypotheses by regression analysis and structural equation model. The analysis confirmed that for Chinese university students the entrepreneurial attitude and perceived behavioral control were important antecedent variables that shape the entrepreneurial intention. It was also shown that leadership and innovation have a positive influence on the entrepreneurial attitude, while leadership and planning raise the level of perceived behavioral control. As a result, leadership forms the entrepreneurial intention through the entrepreneurial attitude and perceived behavior control, and innovation affects the entrepreneurial intention through the entrepreneurial attitude, while planning affects the entrepreneurial intention through perceived behavior control. Therefore, entrepreneurship education that emphasizes leadership, innovation and planning is required for Chinese college students as a potential entrepreneur. These three factors could also be important personal characteristics when choosing a potential entrepreneur.

Corrosion Characteristics of Excavated Bronze Artifacts According to Corrosion Environment (부식 환경에 따른 출토 청동 유물의 부식 특성)

  • Jang, Junhyuk;Bae, Gowoon;Chung, Kwangyong
    • Korean Journal of Heritage: History & Science
    • /
    • v.53 no.1
    • /
    • pp.24-33
    • /
    • 2020
  • In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

Microbial Leaching of Iron from Magnetite (미생물을 이용한 자철석으로부터 철 침출에 관한 연구)

  • Roh, Yul;Oh, Jong-Min;Seo, Yong-Jae;Jang, Hee-Dong
    • Journal of the Mineralogical Society of Korea
    • /
    • v.19 no.4 s.50
    • /
    • pp.265-275
    • /
    • 2006
  • It is in its infancy to use bacteria as a novel biotechnology for leaching precious and heavy metals from raw materials. The objective of this study was to investigate biogeochemical processes of iron leaching from magnetite reduction by iron-reducing bacteria isolated from intertidal flat sediments, southwestern part of Korea. Microbial leaching experiments were performed using commercial magnetite, Aldrich magnetite, in well-defined mediums with and without bacteria. Water soluble Fe production was determined by ICP analysis of bioleached samples in comparison to uninoculated controls, and the resulting precipitated solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The extent of iron leaching from magnetite in the aerobic conditions (Fe = 107 ppm) was higher than that in the anaerobic environments (Fe = 94 ppm). In the anaerobic conditions, Fe(III) in commercial magnetite was also reduced to Fe(II), but no secondary mineral phases were observed. Amorphous iron oxides formed in the medium under aerobic conditions where there was sufficient supply of oxygen from the atmosphere. SEM observation suggests that the reduction process involves dissolution-precipitation mechanisms as opposed to solid state conversion of magnetite to amorphous iron oxides. The ability of bacteria to leach soluble iron and precipitate amorphous iron oxides from crystalline magnetite could have significant implications for biogeochemical processes in sediments where Fe(III) in magnetite plays an important role in the largest pool of electron acceptor as well as the tool as a novel biotechnology for leaching precious and heavy metals from raw materials.