130323 paper study 준섭
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The study aimed to investigate the hypothesis that the P protein influences tyrosine and tyrosinase localization. The results showed that tyrosine transport was not different between wild-type and P mutant melanocytes. While total tyrosinase activity was higher in P mutant cells, tyrosinase localization to melanosomes was impaired. This indicates that P protein plays an important role in localizing and stabilizing tyrosinase in melanosomes, rather than transporting tyrosine.
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![The pink-eyed dilution phenotype in mice arises from mutations in the p gene; in
humans, analogous mutations in the P gene result in oculocutaneous albinism
type 2. Although the molecular mechanisms which underlie this phenotype remain
obscure, it has been postulated that mutations in p result in defective tyrosine
transport into murine melanosomes, resulting in hypopigmentation and
diminished coat color. However, we previously reported no difference in
melanosomal tyrosine transport in unpigmented, melanoblast-like pinkeyed
dilution (pcp/pcp), and in pigmented (melan-a) murine melanocytes. In this study,
we utilized melan-p1 cells, more differentiated pink-eyed dilution ( pcp/p25H)
melanocytes which can be induced to produce melanin, to characterize the
melanogenic lesion(s) more definitively. Uptake of [3H]tyrosine into melan-a
melanosomes did not differ significantly from uptake into melanosomes derived
from melan-p1 melanocytes, further arguing against its critical role as a tyrosine
transporter. Pink-eyed dilution melanocytes incubated in high tyrosine
concentrations became extremely pigmented as they became confluent and
secreted large amounts of black material into the medium. Total cellular tyrosinase
activity in melan-p1 melanocytes was significantly higher than that in melan-a
melanocytes (which are wild-type at the p locus), but the localization of tyrosinase
to melanosomes was impaired in melan-p1 melanocytes compared to melan-a
melanocytes. These results indicate that mechanisms other than deficient tyrosine
transport are involved in the pink-eyed dilution phenotype and that this protein
may serve a chaperone-like or stabilizing function in melanocytes. © 1998
Academic Press](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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Mn ps manuscript
This document summarizes an experiment to isolate tissue plasminogen activator (tPA) from HeLa cell culture broth using magnetic nanoparticles (MNPs). tPA helps break down blood clots and has applications in thrombolytic therapy. The experiment involved binding tPA to MNPs, washing away unbound proteins, then eluting tPA from the MNPs. Absorbance measurements and assays showed tPA was present in the load and spent samples but concentrations were low in the eluates. SDS-PAGE and zymography gels confirmed tPA activity in the load and spent but not eluates, possibly due to low concentrations or protein denaturation during elution. The experiment demonstrated the potential
Trp operon
The document discusses the trp operon in prokaryotes. The trp operon encodes for enzymes involved in the biosynthesis of tryptophan. It consists of 5 structural genes (trpE, trpD, trpC, trpB, trpA) that are regulated by a single promoter. The expression of the operon is controlled by the trp repressor and feedback inhibition via the mechanism of attenuation. When tryptophan levels are high, the trp repressor binds to the operator region and blocks transcription. When levels are low, transcription occurs and the enzymes are produced to synthesize tryptophan via a series of reactions.
Phenylketonuria Essay
This document summarizes research on the diagnostic value and molecular regulatory mechanism of microRNA miR-193a-5p in lung cancer. Meta-analysis of microarrays showed miR-193a-5p has different expression levels in peripheral blood versus tissue, with potential diagnostic value. Bioinformatics analysis identified predicted and validated miR-193a-5p target genes involved in processes like neuron apoptosis, organelle membrane permeability, and tubulin modification. Further research is needed to validate findings and better understand the inverse peripheral and tissue expression of miR-193a-5p in lung cancer.
Trp operon
The trp operon is a group of genes in E. coli bacteria that encodes enzymes for the biosynthesis of tryptophan. It was the first repressible operon discovered in 1953. The trp operon is expressed when tryptophan levels are low and repressed when tryptophan levels are high through a negative feedback mechanism. Specifically, tryptophan binds to the trp repressor, causing a conformational change that allows it to bind to the operator region and prevent transcription. Additionally, the trp operon uses an attenuation mechanism to control expression, where stem loop structures form to allow or prevent transcription depending on tryptophan levels.
GENE REGULATION.pptx
The document summarizes gene regulation in prokaryotes and eukaryotes.
In prokaryotes:
- Genes are organized into operons that are regulated by repressor proteins binding to operator sequences. This allows for coordinated expression of genes in response to environmental conditions, as seen in the lac and tryptophan operons.
In eukaryotes:
- Gene expression is influenced by chromatin structure and modifications to histone proteins like acetylation and methylation that make DNA more or less accessible. DNA methylation can also silence genes. Post-transcriptional mechanisms further regulate gene expression.
Lac operon sohil
The document discusses various mechanisms of gene expression and regulation in prokaryotes and eukaryotes. It explains that gene expression involves the transcription of DNA into mRNA and the translation of mRNA into protein. In prokaryotes, genes may be organized into operons and regulated through repression and induction. The lactose and tryptophan operons are discussed as examples. Eukaryotes have additional complexities in gene expression including RNA processing, alternative splicing, and transport of mRNA. Gene expression is regulated at transcriptional, post-transcriptional, translational, and post-translational levels.
Rna synthesis and processing
1. The document discusses RNA synthesis and processing, including the different types of RNA (mRNA, rRNA, tRNA), the process of transcription, initiation, elongation, and termination.
2. It also covers RNA processing after transcription, including 5' capping, polyadenylation, splicing, and modifications to tRNA, rRNA and other non-coding RNAs.
3. The clinical applications of understanding RNA synthesis and processing are discussed, such as targets for antibiotics, implications for genetic diseases, and miRNA roles in various human health conditions.
The efficiency of extracts of plants that have
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The efficiency of extracts of plants that have
This document summarizes a study that aims to determine the efficiency of melatonin extracts from the Achillea millefolium plant in treating Parkinson's disease rats. The study will involve inducing Parkinson's disease in rats using rotenone injections. The rats will then be given various concentrations of the Achillea melatonin extract via subcutaneous injections daily to observe any reductions in involuntary movements. The objective is to prove that the melatonin extract can help control Parkinson's symptoms by improving dopamine production. It is hypothesized that higher concentrations of the extract will result in less tremors and movements in the rats.
2nd_Med-NS_2020_L9.pptx
This document discusses several neurotransmitters and gliotransmitters:
1. D-serine, which is released by astrocytes and binds to NMDA receptors.
2. Purinergic neurotransmitters like ATP and adenosine, which signal through P1 and P2 receptors and are involved in processes like sleep, epilepsy, and hypoxia.
3. Melatonin, a hormone synthesized from serotonin in the pineal gland that provides circadian timing cues and is implicated in sleep and affective disorders.
4. NAA and NAAG, which are involved in myelin synthesis and trafficking in neurons.
Gene expression
Gene expression in eukaryotes is regulated through various mechanisms including histone modification, DNA methylation, enhancers, and combinations of regulatory proteins. Gene regulation occurs through positive and negative elements that increase or decrease expression. Key examples are the lac and tryptophan operons in prokaryotes, which are regulated by repressors and inducers to control metabolic pathways in response to environmental conditions.
Plegable bm zule chavez.
This document discusses several mechanisms involved in gene expression and regulation at the molecular level. It describes how DNA is transcribed into messenger RNA, which then undergoes processing and modification before being translated into protein. Specifically, it mentions RNA methylation, transfer RNA, and epigenetic factors that can regulate gene expression without changing DNA sequence. The document also provides examples of how mutations in these molecular processes could lead to diseases or defective proteins if not properly regulated by the cell's quality control mechanisms.
Gene expression and regulation
The following topics are discussed
. Prokaryotic gene expression and regulation
Prokaryotic “gene structure”
The basic structure of Operon
Lactose Operon” regulation
Tryptophan Operon” regulation
2. Eukaryotic gene expression and regulation
Eukaryotic gene structure
Regulons
GENE EXPRESSION AND REGULATION.pptx
This document discusses gene expression and regulation. It begins by defining gene expression as the process by which information from a gene is used to create a functional gene product like a protein. This occurs through two main steps - transcription of DNA into mRNA in the nucleus, and translation of mRNA into proteins in the cytoplasm. Regulation of gene expression controls which genes are expressed, such as through the lac operon which expresses lactose metabolism genes only in the presence of lactose. The lac operon provides an example of positive and negative gene regulation through a repressor protein that binds to the operon's DNA to block or allow transcription.
Trp operon
The trp operon contains a cluster of genes involved in tryptophan biosynthesis that are under the control of a single promoter. It was the first repressible operon discovered in E. coli in 1953. The trp operon contains structural genes that encode enzymes for tryptophan synthesis, as well as a promoter, operator, and regulatory genes. Tryptophan acts as an effector molecule that binds to the repressor protein, increasing its affinity for the operator sequence and repressing transcription when tryptophan is present. The trp operon is also regulated by transcriptional attenuation, where tryptophan levels affect the formation of termination or anti-termination hairpin loops in the mRNA.
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131116 paper study 준섭
This document describes methods for stably transfecting cell lines to create new cell lines. It compares the calcium phosphate precipitation method, spontaneous transfection method, and lipofection method. It also details monitoring transfection efficiency by fluorescence microscopy and spectroscopy. Results show the calcium phosphate method worked best for most cell lines tested except HeLa cells. Stable transfection of HeLa cells with a plasmid increased fluorescence over 21 days then plateaued. Plasmid DNA concentration did not correlate with fluorescence yield.
131116 paper study 준섭
This document describes methods for stably transfecting cell lines to create new cell lines. It compares the calcium phosphate precipitation method, spontaneous transfection method, and lipofection method. It also details monitoring transfection efficiency by fluorescence microscopy and spectroscopy. Results show the calcium phosphate method worked best for most cell lines tested except HeLa cells. Stable transfection of HeLa cells with a plasmid increased fluorescence over 21 days then plateaued. Plasmid DNA concentration did not correlate with fluorescence yield.
130907 paper study 준섭
Artemisinic acid inhibits melanogenesis in human melanocytes by reducing cholesterol synthesis. It decreases cholesterol content by downregulating the HMG CoA reductase gene, which is critical for cholesterol synthesis. Artemisinic acid treatment leads to downregulation of the C/EBP α gene, which mediates reduced expression of the HMG CoA reductase gene. This inhibition of cholesterol synthesis attenuates melanogenesis in human melanocytes.
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Melanogenesis proceeds in three steps: production of cysteinyldopas, oxidation to pheomelanin, and production of eumelanin. Dopachrome tautomerase (Dct) catalyzes the tautomerization of dopachrome to increase the ratio of DHICA in eumelanin and eumelanin production. The initial production of cysteinyldopas and subsequent pheomelanin favors pheomelanogenesis over eumelanogenesis as long as cysteinyldopa levels remain high. The reactivity of o-quinones, which are highly reactive, chemically controls the early melanogenesis process.
131116 paper study 준섭
1. The document describes methods for stably transfecting cell lines, including calcium phosphate transfection, lipofection, and spontaneous transfection.
2. It examines the efficiency of transfection for different cell lines using green fluorescent protein and red fluorescent protein plasmids.
3. Results show that calcium phosphate transfection was more efficient than spontaneous transfection for most cell lines tested, except HeLa cells. Stable transfection of HeLa cells over 21 days resulted in gradually increasing fluorescent intensity that then remained constant.
130907 paper study 준섭
Artemisinic acid inhibits melanogenesis in human melanocytes by reducing cholesterol synthesis. It decreases cholesterol content by downregulating the HMG CoA reductase gene, which is critical for cholesterol synthesis. Artemisinic acid treatment leads to downregulation of the C/EBP α gene, which mediates reduced expression of the HMG CoA reductase gene. This inhibition of cholesterol synthesis attenuates melanogenesis in human melanocytes.
130824 paper study 준섭
Melanogenesis proceeds in three steps: production of cysteinyldopas, oxidation to pheomelanin, and production of eumelanin. Dopachrome tautomerase catalyzes the conversion of dopachrome to dihydroxyindole-2-carboxylic acid, increasing eumelanin production. The initial production of cysteinyldopas determines the ratio of pheomelanin to eumelanin, as cysteinyldopas accumulate when cysteine concentrations are above 1 μM and pheomelanogenesis is favored over eumelanogenesis when cysteinyldopa levels exceed 10 μM. O-quinones are highly reactive, readily binding to cysteine residues
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The document summarizes the process of extracting and isolating a compound from the Chinese herbal medicine Erigeron breviscapus that has depigmenting effects. Materials and methods describe culturing cells and conducting inhibition and isolation assays. Through fractionation of the plant extract, the active compound (2Z,8Z)-Matricaria Acid Methyl Ester was isolated. Results show the compound decreased melanin synthesis and tyrosinase expression in cells, demonstrating its potential as a skin whitening agent for treating hyperpigmentation.
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This document investigates the physiological effects of He-Ne laser irradiation on two melanoblast (MB) cell lines - the immature NCCmelb4 and the more differentiated NCCmelan5. The results showed that He-Ne laser irradiation did not affect the growth of either cell line but did induce mobility in the NCCmelb4 cells. It also decreased attachment of NCCmelb4 cells to fibronectin and increased expression of pp125FAK, a protein involved in cell mobility. The laser treatment had little effect on the locomotion of the more differentiated NCCmelan5 cells.
130817 paper 이신애
The document summarizes a study analyzing the binding and cleavage of collagen by MMP-1. Key findings include:
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Paper review 전상귀 20130817
This paper demonstrated using lauryl alcohol as a feedstock for producing sophorolipids using Candida bombicola. Sophorolipids are biosurfactants that have antimicrobial and emulsifying properties. The study found that sophorolipid production was maximized at 96 hours of incubation, with 10% glucose concentration, initial pH of 6.0, and a temperature of 30°C. The produced sophorolipids reduced surface tension more than synthetic surfactants and had good emulsification activity and antibacterial effects against both gram-positive and gram-negative bacteria.
13.8.3 병권
Pmel17 is an important structural component of melanosomes that is present in the limiting membrane of stage I melanosomes and enters intralumenal vesicles. Melanosomes undergo four stages of biogenesis, starting as non-pigmented stage I melanosomes derived from the endosomal system, acquiring internal striations in stage II, depositing melanin pigment in stage III, and becoming fully melanized in stage IV. Melanosome transport requires Rab27a GTPase association with melanosomes and regulation of their movement along microtubules and actin cytoskeleton to the cell periphery.
13.7.27 병권
This document summarizes factors that determine skin color, including melanin, carotene, and hemoglobin. It discusses the architecture of the skin, including the neural crest and melanocytes. It also examines the regulation of constitutive and facultative skin pigmentation, how melanin protects the skin from UV exposure, disorders of skin pigmentation like albinism and vitiligo, and different approaches to regulating skin pigmentation.
130629paper
This document summarizes small interfering RNAs (siRNAs), including their classification, biogenesis, mechanisms of action, and functions. siRNAs are non-coding RNAs 19-28 nucleotides in length that are derived from double-stranded RNA and induce gene silencing through base pairing with target molecules. The document outlines the major classifications of siRNAs and how they are processed from precursor molecules by RNase III enzymes like Dicer and Drosha. It also describes the four mechanisms by which siRNAs carry out gene silencing, including endonucleolytic cleavage, translational repression, transcriptional repression, and DNA elimination.
130629 paper 창하
The study investigated the production of sophorolipids (SLs) by Torulopsis bombicola using different lipid precursors such as glucose, hexadecane, and soybean oil. Liquid chromatography-mass spectrometry analysis showed that hexadecane as a precursor produced a cleaner mixture of predominantly diacetylated lactonic SL isomers with palmitate. Soybean oil as a precursor resulted in SLs corresponding to its fatty acid composition. Production of lactonic SLs increased significantly following addition of the lipid precursors and peaked in stationary phase, while acidic SLs increased gradually. Hexadecane provided the highest SL yield and purity compared to soybean oil and glucose precursors.
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130323 paper study 준섭
- 1. <13.03.23 > INHA UNIVERSITY-김준 섭 ▶Objective : P protein이 Tyrosine과 Tyrosinase의 localization에 영향을 미 친다는 가설에 대한 논문을 알아보기
- 2. The pink-eyed dilution phenotype in mice arises from mutations in the p gene; in humans, analogous mutations in the P gene result in oculocutaneous albinism type 2. Although the molecular mechanisms which underlie this phenotype remain obscure, it has been postulated that mutations in p result in defective tyrosine transport into murine melanosomes, resulting in hypopigmentation and diminished coat color. However, we previously reported no difference in melanosomal tyrosine transport in unpigmented, melanoblast-like pinkeyed dilution (pcp/pcp), and in pigmented (melan-a) murine melanocytes. In this study, we utilized melan-p1 cells, more differentiated pink-eyed dilution ( pcp/p25H) melanocytes which can be induced to produce melanin, to characterize the melanogenic lesion(s) more definitively. Uptake of [3H]tyrosine into melan-a melanosomes did not differ significantly from uptake into melanosomes derived from melan-p1 melanocytes, further arguing against its critical role as a tyrosine transporter. Pink-eyed dilution melanocytes incubated in high tyrosine concentrations became extremely pigmented as they became confluent and secreted large amounts of black material into the medium. Total cellular tyrosinase activity in melan-p1 melanocytes was significantly higher than that in melan-a melanocytes (which are wild-type at the p locus), but the localization of tyrosinase to melanosomes was impaired in melan-p1 melanocytes compared to melan-a melanocytes. These results indicate that mechanisms other than deficient tyrosine transport are involved in the pink-eyed dilution phenotype and that this protein may serve a chaperone-like or stabilizing function in melanocytes. © 1998 Academic Press
- 3. P protein tyrosine transport wild-type : Melan-a (a/a, p/p) P mutant : Melan-p1 (a/a, pcp/p25H) p gene oculocutaneous albinism type 2 mutation <Postulation> <In this study> p gene tyrosine transport X cellular tyrosinase activity : melan-p1 > melan-a melan-p1 : localization of tyrosinase to melanosomes was impaired. <mechanisms> P protein may serve a chaperone-like or stabilizing function in melanocytes.
- 4. tyrosine~! P protein이 tyrosine을 transport할까요? NO~! melanosome •carrier-mediated process •energy-requiring •affected by a pH gradient tyrosinase : melan-p1 cells > melan-a cells melan-p1 : melanogenic enzyme to melanosomes was dramatically impaired p protein plays an important role in localizing and/or stabilizing tyrosinase in the melanosome.
- 5. Cell culture : wild-type : Melan-a (a/a, p/p) C57BL/6 mice P mutant : Melan-p1 (a/a, pcp/p25H) pink eyed dilution mice Tyrosine transport assays : [3H-tyrosine] Subcellular fractionation : tyrosine transport assay, tyrosinase activity Light microscopy Enzyme assays and protein determinations : tyrosine hydroxylase assay Western immunoblotting analysis
- 6. 1. Tyrosine Transport Studies FIG. 1. [3H]Tyrosine uptake into melanosomes derived from melan-a or melan-p1 melanocytes. darker bars : melan-a lighter bars : melan-p1 melan a와 melan-p는 별 차이가 없다. tyrosine transport : 50uM이 10uM 약 2배 tyrosine transport X
- 7. 2. Tyrosine Induction of Melanin Production FIG. 2. Melanin secreted into media by melan-a or melan-p1 melanocytes. (4) melan-p, 1.0 mM tyr. (1) melan-a, 0.2 mM tyr (2) melan-p, 0.2 mM tyr (3) melan-a, 1.0 mM tyr Melanin : melan-p > melan-a tyrosine tyrosine melan-p1 <melanin extracellular medium>
- 8. FIG. 3. Phenotypic appearance of melanocytes cultured at varying concentrations of tyrosine. Bar, 50 um. 2. Tyrosine Induction of Melanin Production <tissue chamber slides> melan-a : relatively stable melan-p1 : tyrosinase dendritic <phenotype>
- 9. 3. Subcellular Distribution of Tyrosinase tyrosine hydroxlase assay tyrosinase activity tyrosinase activity : melan-p1 > melan-a melan-a : melanosome > cell extract (5배) melan-p1 : melanosome < cell extract
- 10. FIG. 4. Tyrosinase in subcellular fractions of melan-a or melan-p1 melanocytes. Ext : total extract of cells MS : melanosomal fraction imimmunoreactive tyrosinase present in cell extracts and in melanosome fractions 3. Subcellular Distribution of Tyrosinase <Western immunoblotting> tyrosinase amount : melan-a > melan-p1 αPEP-7 antibody tyrosinase의 carboxylic tail melanosome에 위치한 tyrosinase를 잘 인지 <conflict>
- 11. •tyrosinase •tyrosinase stability •melanogenic enzymatic functions •melanin production p gene mutation result tyrosinase activity : melan-p1 > melan-a •studies were performed on extracts of tissues •melanocytes are a relatively small percentage of the total population (1-2%) •decreased numbers of mutant elanocytes are present. p protein plays an important role in assembling and stabilizing a complex of melanosomal proteins which includes tyrosinase