• 대한약리학회지
• /
• 제31권2호
• /
• pp.165-177
• /
• 1995

Dissociated cell cultures from rat embryonic ventral mesencephalon were used to evaluate the mechanisms of $MPP^+$ neurotoxicity. The cells were treated with MPTP or $MPP^+$ and the viability of the cells was assessed biochemically; tyrosine hydroxylase (TH) immunoreactivity, protein, intracellular ATP and lactate content and lipid peroxidation. Also the generation of the intracellular oxidants was measured after loading 2', 7‘-dichlorofluorescin diacetate to the cells. When cultures were exposed to 0.1 mM $MPP^+$, at 2 hour incubation lactate was significantly accumulated in the cells and then the intracellular ATP content and TH immunoreactivity were decreased dose- and time-dependently. But, malondialdehyde as an index for lipid peroxidation was not changed even though the generation of the intracellular oxidants was stimulated by the addition of $MPP^+$. On the other hand, 1 mM MPTP significantly reduced the TH immunoreactivity at 24 hour exposure without any change in the intracellular A TP, lactate and MDA content until 6 hour exposure. And also MPTP inhibited the generation of the intracellular oxidants from control cells and $MPP^+$ exposed cells. These results indicate that cytotoxicity of $MPP^+$ is mediated by inhibiting the mitochondrial energy metabolism rather than generating the intracellular oxidants. And MPTP would have direct action in addition to conveting to the toxic metabolite, $MPP^+$ to exert the toxicity on the dopaminergic neurons.

• Korean Journal of Acupuncture
• /
• 제37권2호
• /
• pp.97-103
• /
• 2020

Objectives : Parkinson's disease, a progressive neurodegenerative disease, is caused by the loss of dopaminergic neurons in the substantia nigra. There is no clear treatment or remedy for Parkinson's disease; therefore, the development of novel therapies related to anti-inflammatory and antioxidant effects is required. This study was performed to evaluate the neuroprotective effect of water extracts from Cervi Cornu (CC) in dopaminergic cells. Methods : We studied effects of CC on apoptosis, cell death and inflammation in SH-SY5Y neuroblastoma cells treated by methylpyridinium ion (MPP+). SH-SY5Y cell line was treated with CC for 24 hours and then 500 μM MPP+ for 18 hours. Results : Cervi Cornu treatment inhibited the decrease in tyrosine hydroxylase (TH) expression and decreased the activation of inflammatory factors mitochondrial cytochrome C oxidase (COX2) and inducible NO synthase (iNOS) against MPP+ neurotoxicity. Apoptosis factors BCL2 associated X, apoptosis regulator (BAX) levels were decreased and B-Cell CLL/Lymphoma 2 (BCL2) levels were increased. Conclusions : These results suggest that CC treatment had neuroprotective effects in the SH-SY5Y neuroblastoma cells against toxicity induced by MPP+. The results suggest new possibilities of CC for the treatment of Parkinson's disease.

• Journal of Microbiology and Biotechnology
• /
• 제25권10호
• /
• pp.1648-1652
• /
• 2015

Azaphilone polyketides are synthesized by iterative non-reducing fungal polyketide synthases (NR-fPKSs) with a C-terminus reductive domain (-R). Several azaphilone biosynthetic gene clusters contain a putative serine hydrolase gene; the Monascus azaphilone pigment (MAzP) gene cluster harbors mppD. The MAzP productivity was significantly reduced by a knockout of mppD, and the MAzP NR-fPKS-R gene (MpPKS5) generated its product in yeast only when co-expressed with mppD. Site-directed mutations of mppD for conserved Ser/Asp/His residues abolished the product formation from the MpPKS5/mppD co-expression. MppD and its homologs are thus proposed as a new protein factor involved in the product formation of NR-fPKS-R.

• IEIE Transactions on Smart Processing and Computing
• /
• 제5권6호
• /
• pp.454-461
• /
• 2016

A maximum power point tracking (MPPT) system with fast-tracked time and high power efficiency is presented in this paper. The proposed MPPT system uses an unbounded binary search (UBS) algorithm that continuously tracks the maximum power point (MPP) with a binary system to follow the MPP under rapid-weather-change conditions. The proposed algorithm can decide the correct direction of the MPPT system while comparing the previous power point with the present power point. And then, by fixing the MPP until finding the next MPP, there is no oscillation of voltage MPP, which maximizes the overall power efficiency of the photovoltaic module. With these advantages, this proposed UBS is able to detect the MPP more effectively. This MPPT system is based on a boost converter with a micro-control unit to control analog-to-digital converters and pulse width modulation. Analysis of this work and experimental results show that the proposed UBS MPPT provides fast, accurate tracking with no oscillation in situations where weather rapidly changes and shadow is caused by all sorts of things. The tracking time is reduced by 87.3% and 66.1% under dynamic-state and steady-state operation, respectively, as compared with the conventional 7-bit perturb and observe technique.

• BMB Reports
• /
• 제51권11호
• /
• pp.590-595
• /
• 2018

Parkinson's disease (PD) is a common chronic neurodegenerative disease mainly caused by the death of dopaminergic neurons. However, no complete pharmacotherapeutic approaches are currently available for PD therapies. 1-methyl-4-phenylpyridinium $(MPP^+)$-induced SH-SY5Y neurotoxicity has been broadly utilized to create cellular models and study the mechanisms and critical aspects of PD. In the present study, we examined the role of a novel azetidine derivative, 3-(naphthalen-2-yl(propoxy)methyl)azetidine hydrochloride (KHG26792), against $MPP^+$-induced neurotoxicity in SH-SY5Y cells. Treatment of KHG26792 significantly attenuated $MPP^+$-induced changes in the protein levels of Bcl-2 and Bax together with efficient suppression of $MPP^+$-induced activation of caspase-3 activity. KHG26792 also attenuated mitochondrial potential and levels of ROS, $Ca^{2+}$, and ATP in $MPP^+$-treated SH-SY5Y cells. Additionally, KHG26792 inhibited the induced production of nitric oxide and malondialdehyde. Moreover, the protective effect of KHG26792 is mediated through regulation of glutathione peroxidase and GDNF levels. Our results suggest a possibility that KHG26792 treatment significantly protects against $MPP^+$-induced neurotoxicity in SH-SY5Y cells and KHG26792 may be a valuable therapeutic agent for the treatment of PD induced by an environmental toxin.

• 한국항행학회논문지
• /
• 제24권4호
• /
• pp.291-298
• /
• 2020

본 연구는 입자 무리 최적화 (PSO; particle swarm optimization) 알고리즘을 이용하여 기존의 MPPT 알고리즘보다 신속하게 MPP를 추적할 수 있는 모델을 제안하였다. 제안 모델은 PSO 알고리즘에서 gbest 및 pbest의 가속 상수를 높게 설정하여 신속하게 MPP 지점을 추적하고 이로 인한 전력 불안정 문제점을 제거하였다. 또한, 일사량의 급격한 변화에 따른 태양광 패널의 전력 변화를 감지하여 알고리즘을 다시 실행하였다. 실험결과, 일사량이 691.5W/m2에 대해서 MPPT 시간이 0.03초와 전력이 131.65로서 기존의 P&O와 INC 알고리즘보다 높은 전력과 빠른 속도로 MPP를 추적하였으며, 일사량 변화에 따라 신속하게 MPP를 추적하였다. 제안 모델은 태양광 패널이 병렬로 연결되어 있는 태양광 발전소에서 부분적인 음영에 의해 전력량의 변화를 감지하였을 경우에도 적용할 수 있다. 본 연구는 MPPT 알고리즘을 개선하기 위해 MFO (moth flame optimization) 및 WOA (whale optimization algorithm)와 같은 최적화 알고리즘에 대한 비교 연구가 필요하다.

• 한국정보기술학회논문지
• /
• 제17권9호
• /
• pp.19-30
• /
• 2019

태양광 발전은 일사량 및 온도 등 외부변화에 따른 안정적이고 효율적인 최대 전력 출력 전력점을 추적하기 위한 MPPT 알고리즘이 필요하다. 본 연구는 인공 신경망을 이용하여 기존 MPPT 알고리즘보다 신속하게 MPP를 추적할 수 있는 모델을 구현하였다. 제안 모델은 인공 신경망의 학습 데이터를 위해 다양한 일사량과 온도의 조합에 대해서 기존 MPPT 알고리즘으로 MPP의 전류와 전압을 찾았다. 획득한 MPP 데이터는 입력 노드를 일사량과 온도로 출력 노드를 전류와 전압으로 하여 학습하였다. 실험결과 일사량과 온도 변화가 있는 0~0.3t 구간에서 추적시간은 기존 알고리즘인 P&O와 InC 그리고 Fuzzy는 각각 잘못된 계산식t, 0.49t 그리고 0.4076t이였으며, 제안 모델은 0.32511t로서 기존 알고리즘 보다 0.1t 이상 신속하게 MPP를 추적하였다.

• BMB Reports
• /
• 제44권5호
• /
• pp.312-316
• /
• 2011

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridium ion (MPP$^+$) have been shown to induce Parkinson's disease-like symptoms as well as neurotoxicity in humans and animal species. Recently, we reported that maintenance of redox balance and cellular defense against oxidative damage are primary functions of the novel antioxidant enzyme cytosolic NADP$^+$-dependent isocitrate dehydrogenase (IDPc). In this study, we examined the role of IDPc in cellular defense against MPP$^+$-induced oxidative injury using PC12 cells transfected with IDPc small interfering RNA (siRNA). Our results demonstrate that MPP$^+$-mediated disruption of cellular redox status, oxidative damage to cells, and apoptotic cell death were significantly enhanced by knockdown of IDPc.

• 전력전자학회논문지
• /
• 제25권1호
• /
• pp.29-36
• /
• 2020

In this study, a variable step algorithm is proposed on the basis of the perturb and observe method. The proposed algorithm can follow the maximum power point (MPP) quickly when solar irradiance changes rapidly. The proposed technique uses the voltage change characteristic at the MPP when the environment changes because of insolation or temperature. The MPP is tracked through the voltage control using a variable step method. This method determines the sudden change of solar irradiance by setting the threshold value and operates in fast tracking mode to track the MPP rapidly. When the operation point reaches the MPP, the mode switches to the variable step mode to minimize the steady state error. In addition, the output disturbance is decreased through the optimization of the control method design. The performance of the proposed MPPT algorithm is verified through simulation and experiment.

• Journal of Microbiology and Biotechnology
• /
• 제29권6호
• /
• pp.897-904
• /
• 2019

Monascus purpureus recombinant mppC and mpp7 knockout strains were subjected to extractive fermentation in the context of azaphilone pigment production. Inclusion of Diaion HP-20 resin resulted in the selective production of unreduced azaphilone congeners, in addition to the early intermediate FK17-P2a, from ${\Delta}mppC$ and ${\Delta}mpp7$ strains that would otherwise mainly produce reduced congeners. Structural determination of two novel unreduced azaphilones from the ${\Delta}mpp7$ strain was accomplished. The unreduced azaphilone compound was converted into the cognate reduced congener in recombinant M. purpureus strains, demonstrating its intermediate role in azaphilone biosynthesis. This study demonstrates the possibility that extractive fermentation with Diaion HP-20 resin can be used to obtain cryptic azaphilone metabolites.