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1.
Front Pediatr ; 10: 995167, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36479288

RESUMO

Children with underlying medical conditions potentially develop severe illness from Coronavirus disease 2019 (COVID-19). The use of vaccines against COVID-19 is currently recommended for the pediatric population. The COVID-19 vaccine has a temporal association with the occurrence of myocarditis. Although most patients with COVID-19 vaccination-associated myocarditis (C-VAM) exhibit a mild clinical course and rapid recovery, C-VAM potentially causes electrical instability and sudden cardiac death. Herein, we report the case of a 17-year-old woman who presented with chest pain and syncope following the first dose of the messenger RNA COVID-19 vaccine. The patient's heart function was impaired, and nonsustained ventricular tachycardia was frequent. Cardiac magnetic resonance (CMR) imaging satisfied the criteria for myocarditis. Despite the administration of immunomodulatory drugs, the patient's heart function was not fully restored, and the concentration of cardiac enzymes remained above the normal range. Persistence of late gadolinium enhancement was observed on short-term follow-up CMR imaging. Although most patients with C-VAM exhibit mild symptoms, significant cardiac arrhythmias potentially occur. Furthermore, some patients with C-VAM demonstrate prolonged impaired heart function and sustained late gadolinium enhancement on follow-up CMR imaging. Therefore, monitoring of electrical and functional cardiac abnormalities in patients with C-VAM is crucial and the long-term outcomes and prognosis of patients with C-VAM require further investigation.

2.
Sci Rep ; 11(1): 21203, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34707216

RESUMO

Brain-derived neurotrophic factor (BDNF) regulates diverse brain functions via TrkB receptor signaling. Due to the expression of TrkB receptors, astrocytes can internalize extracellular BDNF proteins via receptor-mediated endocytosis. Endocytosed BDNF can be re-secreted upon stimulation, but the molecular mechanism underlying this phenomenon remains unrecognized. Our study reveals that vesicle-associated membrane protein 3 (Vamp3) selectively regulates the release of endocytic BDNF from astrocytes. By using quantum dot (QD)-conjugated mature BDNF (QD-BDNF) as a proxy for the extracellular BDNF protein, we monitored the uptake, transport, and secretion of BDNF from cultured cortical astrocytes. Our data showed that endocytic QD-BDNF particles were enriched in Vamp3-containing vesicles in astrocytes and that ATP treatment sufficiently triggered either the antero- or retrograde transport and exocytosis of QD-BDNF-containing vesicles. Downregulation of Vamp3 expression disrupted endocytic BDNF secretion from astrocytes but did not affect uptake or transport. Collectively, these results provide evidence of the selective ability of astrocytic Vamp3 to control endocytic BDNF secretion during BDNF recycling.


Assuntos
Astrócitos/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Exocitose , Proteína 3 Associada à Membrana da Vesícula/metabolismo , Animais , Células Cultivadas , Córtex Cerebral/citologia , Endocitose , Camundongos , Camundongos Endogâmicos C57BL , Pontos Quânticos , Proteína 3 Associada à Membrana da Vesícula/genética
3.
Chemosphere ; 284: 131244, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34175516

RESUMO

The purification of hazardous textile dyeing wastewater has exhibited many challenges because it consists of a complex mixture, including dyestuff, additives, and salts. It is necessary to fabricate membranes with enhanced permeability, fouling resistance, stability, and superior dyes and salts removal from wastewater. Incorporating a highly water stable metal-organic framework (MOFs) into membranes would meet the requirements for the efficient purification of textile wastewater. In this study, nanofiltration (NF) membranes are fabricated by incorporating MIL-100 (Fe) into the chitosan (CS) through film casting technique. The effect of MIL-100 (Fe) loadings on chitosan characterized by FT-IR, XRD, contact angle measurement, FESEM-EDS, XPS, zeta potential, and surface roughness analysis. The membrane characterization confirmed the enhanced surface roughness, pore size, surface charge, and hydrophilicity. The CS/MIL-100 (Fe) membrane exhibited an improved pure water flux from 5 to 52 L/m2h as well as 99% rejection efficiency for cationic methylene blue (MB) and anionic methyl orange (MO). We obtained the rejection efficiency trend for the MB mixed salts in the order of MgSO4 (Mg2+ - 51.6%, SO42- - 52.5%) > Na2SO4 (Na+ - 26.3%, SO42- - 29.3%) > CaCl2 (Ca2+ - 21.4%, Cl- - 23.8%) > NaCl (Na+ - 16.8%, Cl- - 19.2%). In addition, the CS/MIL-100 (Fe) composite membrane showed excellent rejection efficiency and antifouling performances with high recycling stability. These stunning results evidenced that the CS/MIL-100 (Fe) nanofiltration membrane is a promising candidate for removing toxic pollutants in the textile dyeing wastewater.


Assuntos
Quitosana , Purificação da Água , Corantes , Membranas Artificiais , Cloreto de Sódio , Espectroscopia de Infravermelho com Transformada de Fourier , Têxteis
4.
Mitochondrial DNA B Resour ; 5(1): 633-634, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33366679

RESUMO

Iksookimia yongdokensis (Actinopterygii, Cypriniformes, Cobitidae) is known as endemic freshwater fish species in Korea. The total length of I. yongdokensis mitogenome is 16,640 bp, consisting of 13 protein-coding genes (PCGs), 22 tRNAs, 2 rRNAs, and 1 control region (D-loop). The gene arrangement and content were identical with previously recorded mitogenomes of Iksookimia species. Phylogenetic analysis using PCGs and rRNA was examined by maximum likelihood method indicated that genus Iksookimia is taxonomically not stable status according to Iksookimia species and Cobitis species were grouped together.

5.
Mitochondrial DNA B Resour ; 5(1): 856-857, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33366783

RESUMO

In this study, we determined the complete mitochondrial genome sequences of cyprinid freshwater fish, Microphysogobio jeoni, belonging to the subfamily Gobioninae in the order Cypriniformes. The complete mitogenome of M. jeoni was 16,602 bp in length and consisted of 13 protein-coding genes (PCGs), 22 tRNAs, and two rRNAs. The gene order was identical with other Microphysogobio species. The overall nucleotide composition of M. jeoni was A + T: 56.1% and G + C: 43.9%, with slightly AT bias. In the phylogenetic tree, M. jeoni and other congeneric species clearly formed a monophyletic clade, and each species distinguished against each other well.

6.
Mitochondrial DNA B Resour ; 5(1): 860-861, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33366785

RESUMO

In this study, the complete mitochondrial genome sequences of Iksookimia hugowolfeldi, Korean loach species, was determined using next-generation sequencing analysis. The complete mitogenome of I. hugowolfeldi has 16,634 bp in length and consists of 13 protein-coding genes (PCGs), 22 tRNAs, two rRNAs, and one control region (D-loop). Both gene orders and characteristics were exactly accord with mitochondrial genome of other species those belong to the family Cobitidae. Phylogenetic analysis revealed that the establishment of taxonomic relationship between Iksookimia and Cobitis has still uncompleted because of the not distinguished as monophyletic status.

7.
Mitochondrial DNA B Resour ; 5(1): 866-868, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-33366788

RESUMO

The Korean catfish, Liobagrus somjinensis, was recorded in 2010 as a new species of genus Liobagrus. The complete mitochondrial DNA sequence of L. somjinensis was sequenced by next-generation sequencing (NGS) analysis. The assembled mitogenome was 16,526 bp in length and encoded 13 protein-coding genes (PCGs), 22 tRNAs, and 2 rRNAs. The gene arrangement, content, and total size were clearly identical with the congeneric species, L. mediadiposalis. Phylogenetic analysis based on nucleotide dataset, consisting PCGs and rRNA genes revealed the taxonomical relationship in species level among the genus Liobagrus.

8.
Exp Neurobiol ; 29(3): 219-229, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32624506

RESUMO

Understanding brain function-related neural circuit connectivity is essential for investigating how cognitive functions are decoded in neural circuits. Trans-synaptic viral vectors are useful for identifying neural synaptic connectivity because of their ability to be transferred from transduced cells to synaptically connected cells. However, concurrent labeling of multisynaptic inputs to postsynaptic neurons is impossible with currently available trans-synaptic viral vectors. Here, we report a neural circuit tracing system that can simultaneously label postsynaptic neurons with two different markers, the expression of which is defined by presynaptic input connectivity. This system, called "cFork (see fork)", includes delivering serotype 1-packaged AAV vectors (AAV1s) containing Cre or flippase recombinase (FlpO) into two different presynaptic brain areas, and AAV5 with a dual gene expression cassette in postsynaptic neurons. Our in vitro and in vivo tests showed that selective expression of two different fluorescence proteins, EGFP and mScarlet, in postsynaptic neurons could be achieved by AAV1-mediated anterograde trans-synaptic transfer of Cre or FlpO constructs. When this tracing system was applied to the somatosensory barrel field cortex (S1BF) or striatum innervated by multiple presynaptic inputs, postsynaptic neurons defined by presynaptic inputs were simultaneously labeled with EGFP or mScarlet. Our new anterograde tracing tool may be useful for elucidating the complex multisynaptic connectivity of postsynaptic neurons regulating diverse brain functions.

9.
Mitochondrial DNA A DNA Mapp Seq Anal ; 31(6): 221-227, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32552121

RESUMO

Genus Zacco specimens collected in this study were classified genetically as five species, Zacco platypus, Z. temminckii, Z. koreanus and two unidentified species, using DNA barcoding analysis based on 655 bp of mitochondrial cytochrome c oxidase subunit I (COI) gene. Two of unidentified species (Z. sp.1 and Z. sp.2) were considered to be unrecorded or new species of genus Zacco according to genetic distances between Zacco species. In addition, we determined a natural hybrid based on polymorphic base at the diagnostic positions displayed on nuclear recombination activating gene 1 (RAG1) gene (965 bp), and estimated paternal and maternal species of natural hybrid comparing phylogenetic tree between COI and RAG1, and Z. sp.1♀ × Z. koreanus♂, Z. sp.2♀ × Z. koreanus♂ and Z. koreanus♀ × Z. sp.1♂ individuals were confirmed. The habitat of natural hybrids of Z. koreanus between Z. sp.1 and Z. sp.2 was identified as Geum and Yeongsan River, respectively. In our data, only F1 hybrid generation was identified; however, generations after F1 hybrid or backcross were not demonstrated.


Assuntos
Núcleo Celular/genética , Cyprinidae/classificação , DNA/genética , Mitocôndrias/genética , Animais , Cruzamento , Quimera , Cyprinidae/genética , Código de Barras de DNA Taxonômico , Feminino , Genes RAG-1/genética , Variação Genética , Masculino , Filogenia , República da Coreia
10.
Nat Commun ; 9(1): 197, 2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-29321469

RESUMO

The original PDF version of this Article omitted to state that "Jeongho Han and Seok-Hyeon Kang contributed equally to this work" in the affiliations section. This has now been corrected in the PDF version of the Article. The HTML version was correct from the time of publication.

11.
Nat Commun ; 8(1): 751, 2017 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-28963494

RESUMO

Superplastic alloys exhibit extremely high ductility (>300%) without cracks when tensile-strained at temperatures above half of their melting point. Superplasticity, which resembles the flow behavior of honey, is caused by grain boundary sliding in metals. Although several non-ferrous and ferrous superplastic alloys are reported, their practical applications are limited due to high material cost, low strength after forming, high deformation temperature, and complicated fabrication process. Here we introduce a new compositionally lean (Fe-6.6Mn-2.3Al, wt.%) superplastic medium Mn steel that resolves these limitations. The medium Mn steel is characterized by ultrafine grains, low material costs, simple fabrication, i.e., conventional hot and cold rolling, low deformation temperature (ca. 650 °C) and superior ductility above 1300% at 850 °C. We suggest that this ultrafine-grained medium Mn steel may accelerate the commercialization of superplastic ferrous alloys.Research in new alloy compositions and treatments may allow the increased strength of mass-produced, intricately shaped parts. Here authors introduce a superplastic medium manganese steel which has an inexpensive lean chemical composition and which is suited for conventional manufacturing processes.

12.
Sci Rep ; 7(1): 3573, 2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28620213

RESUMO

Recently, Fe-Mn twinning-induced plasticity steels with an austenite phase have been the course of great interest due to their excellent combination of tensile strength and ductility, which carbon steels have never been able to attain. Nevertheless, twinning-induced plasticity steels also exhibit a trade-off between strength and ductility, a longstanding dilemma for physical metallurgists, when fabricated based on the two alloy design parameters of stacking fault energy and grain size. Therefore, we investigated the tensile properties of three Fe-Mn austenitic steels with similar stacking fault energy and grain size, but different carbon concentrations. Surprisingly, when carbon concentration increased, both strength and ductility significantly improved. This indicates that the addition of carbon resulted in a proportionality between strength and ductility, instead of a trade-off between those characteristics. This new design parameter, C concentration, should be considered as a design parameter to endow Fe-Mn twinning-induced plasticity steel with a better combination of strength and ductility.

13.
Daru ; 24: 8, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26980217

RESUMO

BACKGROUND: There are still a large variety of microorganisms among aquatic animals which have not been explored for their pharmacological potential. Hence, present study was aimed to isolate and characterize a potent lactic acid bacterium from fresh water fish sample Zacco koreanus, and to confirm its pharmacological potential. METHODS: Isolation of lactic acid bacteria (LAB) from fresh water fish samples was done using serial dilution method. Biochemical identification and molecular characterization of selected LAB isolate 1I1, based on its potent antimicrobial efficacy, was accomplished using API kit and 16S rRNA gene sequencing analysis. Further, 1I1 was assessed for α-glucosidase and tyrosinase inhibitory potential as well as antiviral efficacy against highly pathogenic human influenza virus H1N1 using MDCK cell line in terms of its pharmacological potential. RESULTS: Here, we first time report isolation as well as biochemical and molecular characterization of a lactic acid bacterium Lactobacillus sakei 1I1 isolated from the intestine of a fresh water fish Z. koreanus. As a result, L. sakei 1I1 exhibited potent antimicrobial effect in vitro, and diameter of zones of inhibition of 1I1 against the tested pathogens was found in the range of 13.32 ± 0.51 to 23.16 ± 0.32 mm. Also L. sakei 1I1 at 100 mg/ml exhibited significant (p < 0.05) α-glucosidase and tyrosinase inhibitory activities by 60.69 and 72.59%, in terms of its anti-diabetic and anti-melanogenic potential, respectively. Moreover, L. sakei 1I1 displayed profound anti-cytopathic effect on MDCK cell line when treated with its ethanol extract (100 mg/ml), confirming its potent anti-viral efficacy against H1N1 influenza virus. CONCLUSIONS: These findings reinforce the suggestions that L. sakei 1I1 isolated from the intestine of fresh water fish Z. koreanus might be a candidate of choice for using in pharmacological preparations as an effective drug.


Assuntos
Inibidores Enzimáticos/farmacologia , Peixes/microbiologia , Lactobacillus/isolamento & purificação , Lactobacillus/fisiologia , Monofenol Mono-Oxigenase/antagonistas & inibidores , Animais , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Cães , Água Doce , Inibidores de Glicosídeo Hidrolases/farmacologia , Hipoglicemiantes/farmacologia , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Lactobacillus/genética , Células Madin Darby de Rim Canino/efeitos dos fármacos , Células Madin Darby de Rim Canino/virologia , RNA Ribossômico/análise , Análise de Sequência de RNA/métodos
14.
Front Microbiol ; 7: 2037, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28066360

RESUMO

This study was undertaken to characterize a lactic acid bacterium 4I1, isolated from the freshwater fish, Zacco koreanus. Morphological, biochemical, and molecular characterization of 4I1 revealed it to be Pediococcus pentosaceus 4I1. The cell free supernatant (CFS) of P. pentosaceus 4I1 exhibited significant (p < 0.05) antibacterial effects (inhibition zone diameters: 16.5-20.4 mm) against tested foodborne pathogenic bacteria with MIC and MBC values of 250-500 and 500-1,000 µg/mL, respectively. Further, antibacterial action of CFS of P. pentosaceus 4I1 against two selected bacteria Staphylococcus aureus KCTC-1621 and Escherichia coli O157:H7 was determined in subsequent assays. The CFS of P. pentosaceus 4I1 revealed its antibacterial action against S. aureus KCTC-1621 and E. coli O157:H7 on membrane integrity as confirmed by a reduction in cell viability, increased potassium ion release (900 and 800 mmol/L), reduced absorption at 260-nm (3.99 and 3.77 OD), and increased relative electrical conductivity (9.9 and 9.7%), respectively. Gas chromatography-mass spectrometry (GC-MS) analysis of the CFS of P. pentosaceus 4I1 resulted in the identification of seven major compounds, which included amino acids, fatty acids and organic acids. Scanning electron microscopic-based morphological analysis further confirmed the antibacterial effect of CFS of P. pentosaceus 4I1 against S. aureus KCTC-1621 and E. coli O157:H7. In addition, the CFS of P. Pentosaceus 4I1 displayed potent inhibitory effects on biofilms formation by S. aureus KCTC-1621 and E. coli O157:H7. The study indicates the CFS of P. pentosaceus 4I1 offers an alternative means of controlling foodborne pathogens.

15.
Mol Brain ; 8: 85, 2015 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-26651479

RESUMO

BACKGROUND: Transmembrane protein 106B (TMEM106B) has been identified as a risk factor for frontotemporal lobar degeneration, which is the second most common form of progressive dementia in people under 65 years of age. Mutations in charged multivesicular body protein 2B (CHMP2B), which is involved in endosomal protein trafficking, have been found in chromosome 3-linked frontotemporal dementia. Despite the number of studies on both CHMP2B and TMEM106B in the endolysosomal pathway, little is known about the relationship between CHMP2B and TMEM106B in the endosomal/autophagy pathway. RESULTS: This study found that endogenous TMEM106B was partially sequestered in CHMP2B-positive structures, suggesting its possible involvement in endosomal sorting complexes required for transport (ESCRT)-associated pathways. The role of single nucleotide polymorphisms of TMEM106B (T185, S185, or S134N) in the ESCRT-associated pathways were characterized. The T185 and S185 variants were more localized to Rab5-/Rab7-positive endosomes compared with S134N, while all of the variants were more localized to Rab7-positive endosomes compared to Rab5-positive endosomes. T185 was more associated with CHMP2B compared to S185. Autophagic flux was slightly reduced in the T185-expressing cells compared to the control or S185-expressing cells. Moreover, T185 slightly enhanced the accumulation of EGFR, impairments in autophagic flux, and neurotoxicity that were caused by CHMP2B(Intron5) compared to S185-expressing cells. CONCLUSIONS: These findings suggest that the T185 variant functions as a risk factor in neurodegeneration with endolysosomal defects. This study provides a better understanding of pathogenic functions of TMEM106B, which is a risk factor for the progression of neurodegenerative diseases that are associated with endosomal defects in the aged brain.


Assuntos
Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Endossomos/fisiologia , Demência Frontotemporal/metabolismo , Proteínas de Membrana/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Neurônios/metabolismo , Polimorfismo de Nucleotídeo Único , Transporte Proteico/fisiologia , Animais , Autofagia , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/fisiologia , Endossomos/química , Éxons/genética , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Células HEK293 , Humanos , Imunoprecipitação , Íntrons/genética , Lisossomos/metabolismo , Proteínas de Membrana/genética , Camundongos , Degeneração Neural , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios/patologia , Mapas de Interação de Proteínas , Proteólise , Proteínas Recombinantes de Fusão/metabolismo , Proteínas rab de Ligação ao GTP/análise , Proteínas rab5 de Ligação ao GTP/análise , proteínas de unión al GTP Rab7
16.
Sci Rep ; 4: 5289, 2014 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-24924480

RESUMO

Controlling the orientations of nanomaterials on arbitrary substrates is crucial for the development of practical applications based on such materials. The aligned epitaxial growth of single-walled carbon nanotubes (SWNTs) on specific crystallographic planes in single crystalline sapphire or quartz has been demonstrated; however, these substrates are unsuitable for large scale electronic device applications and tend to be quite expensive. Here, we report a scalable method based on graphoepitaxy for the aligned growth of SWNTs on conventional SiO2/Si substrates. The "scratches" generated by polishing were found to feature altered atomic organizations that are similar to the atomic alignments found in vicinal crystalline substrates. The linear and circular scratch lines could promote the oriented growth of SWNTs through the chemical interactions between the C atoms in SWNT and the Si adatoms in the scratches. The method presented has the potential to be used to prepare complex geometrical patterns of SWNTs by 'drawing' circuits using SWNTs without the need for state-of-the-art equipment or complicated lithographic processes.

17.
Exp Cell Res ; 319(13): 1998-2005, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23742895

RESUMO

Tar-DNA binding protein of 43kDa (TDP-43) has been characterized as a major component of protein aggregates in brains with neurodegenerative diseases such as frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). However, physiological roles of TDP-43 and early cellular pathogenic effects caused by disease associated mutations in differentiated neurons are still largely unknown. Here, we investigated the physiological roles of TDP-43 and the effects of missense mutations associated with diseases in differentiated cortical neurons. The reduction of TDP-43 by siRNA increased abnormal neurites and decreased cell viability. ALS/FTLD-associated missense mutant proteins (A315T, Q331K, and M337V) were partially mislocalized to the cytosol and neurites when compared to wild-type and showed abnormal neurites similar to those observed in cases of loss of TDP-43. Interestingly, cytosolic expression of wild-type TDP-43 with mutated nuclear localization signals also induced abnormal neurtie morphology and reduction of cell viability. However, there was no significant difference in the effects of cytosolic expression in neuronal morphology and cell toxicity between wild-type and missense mutant proteins. Thus, our results suggest that mislocalization of missense mutant TDP-43 may contribute to loss of TDP-43 function and affect neuronal morphology, probably via dominant negative action before severe neurodegeneration in differentiated cortical neurons.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Neuritos/fisiologia , Neurônios/fisiologia , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Forma Celular/genética , Sobrevivência Celular/genética , Células Cultivadas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos , Degeneração Lobar Frontotemporal/genética , Degeneração Lobar Frontotemporal/patologia , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos ICR , Mutação de Sentido Incorreto/fisiologia , Degeneração Neural/genética , Degeneração Neural/metabolismo , Neuritos/metabolismo , Neuritos/patologia , Neurônios/metabolismo , Neurônios/patologia , Transporte Proteico/genética
18.
Biochem Biophys Res Commun ; 421(3): 544-9, 2012 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-22521643

RESUMO

Endosomal sorting complexes required for transport (ESCRTs) regulate a key sorting step of protein trafficking between endosomal compartments in lysosomal degradation. Interestingly, mutations in charged multivesicular body protein 2B (CHMP2B), which is a core subunit of ESCRT-III, have been identified in some neurodegenerative diseases. However, the cellular pathogenesis resulting from CHMP2B missense mutations is unclear. Furthermore, little is known about their functional analysis in post-mitotic neurons. In order to examine their cellular pathogenesis, we analyzed their effects in the endo-lysosomal pathway in post-mitotic neurons. Interestingly, of the missense mutant proteins, CHMP2B(T104N) mostly accumulated in the Rab5- and Rab7-positive endosomes and caused delayed degradation of EGFR as compared to CHMP2B(WT). Furthermore, CHMP2B(T104N) showed less association with Vps4 ATPase and was avidly associated with Snf7-2, a core component of ESCRT-III, suggesting that it may cause defects in the process of dissociation from ESCRT. Of the missense variants, CHMP2B(T104N) caused prominent accumulation of autophagosomes. However, neuronal cell survival was not dramatically affected by expression of CHMP2B(T104N). These findings suggested that, from among the various missense mutants, CHMP2B(T104N) was associated with relatively mild cellular pathogenesis in post-mitotic neurons. This study provided a better understanding of the cellular pathogenesis of neurodegenerative diseases associated with various missense mutations of CHMP2B as well as endocytic defects.


Assuntos
Autofagia , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Lisossomos/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Neurônios/metabolismo , ATPases Associadas a Diversas Atividades Celulares , Adenosina Trifosfatases/metabolismo , Sobrevivência Celular , Células Cultivadas , Receptores ErbB/metabolismo , Humanos , Mitose , Mutação de Sentido Incorreto , Proteólise
19.
Phys Rev Lett ; 102(23): 235504, 2009 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-19658949

RESUMO

Using a novel morphology segregation technique, we observed minority populations ( approximately 3%) of submicron-sized, cluster-dilute fractal-like aggregates, formed in the soot-formation window (fuel-to-air equivalence ratio of 2.0-3.5) of a premixed flame, to have mass fractal dimensions between 1.2 and 1.51. Our observations disagree with previous observations of a universal mass fractal dimension of approximately 1.8 for fractal-like aerosol aggregates formed in the dilute-limit via three-dimensional diffusion-limited cluster aggregation processes. A hypothesis is presented to explain this observation. Subject to verification of this hypothesis, it may be possible to control the fractal dimension and associated properties of aggregates in the cluster-dilute limit through application of a static electric field during the aggregation process.

20.
Anal Chem ; 80(5): 1401-7, 2008 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18254610

RESUMO

The interaction between atmospheric particles and water vapor impacts directly and significantly the effect that these particles exert on the atmosphere. The hygroscopicity of individual particles, which is a quantitative measure of their response to changes in relative humidity, is related to their internal compositions. To properly include atmospheric aerosols in any model requires knowledge of the relationship between particle size, composition, and hygroscopicity. Here we demonstrate the capability to conduct in real time the simultaneous measurements of individual ambient particle hygroscopic growth factors, densities, and compositions using a humidified tandem differential mobility analyzer that is coupled to an ultrasensitive single-particle mass spectrometer. We use as an example the class of particles that are composed of sulfate mixed with oxygenated organics to illustrate how multidimensional single-particle characterization can be extended to yield in addition quantitative information about the composition of individual particles. We show that the data provide the relative concentrations of organics and sulfates, the density of the two fractions, and particle hygroscopicity.

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