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1.
Proc Natl Acad Sci U S A ; 121(27): e2315944121, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38917002

RESUMO

Chronic inflammation is epidemiologically linked to the pathogenesis of gastrointestinal diseases, including inflammatory bowel disease (IBD) and colorectal cancer (CRC). However, our understanding of the molecular mechanisms controlling gut inflammation remains insufficient, hindering the development of targeted therapies for IBD and CRC. In this study, we uncovered C15ORF48/miR-147 as a negative regulator of gut inflammation, operating through the modulation of epithelial cell metabolism. C15ORF48/miR-147 encodes two molecular products, C15ORF48 protein and miR-147-3p microRNA, which are predominantly expressed in the intestinal epithelium. C15ORF48/miR-147 ablation leads to gut dysbiosis and exacerbates chemically induced colitis in mice. C15ORF48 and miR-147-3p work together to suppress colonocyte metabolism and inflammation by silencing NDUFA4, a subunit of mitochondrial complex IV (CIV). Interestingly, the C15ORF48 protein, a structural paralog of NDUFA4, contains a unique C-terminal α-helical domain crucial for displacing NDUFA4 from CIV and its subsequent degradation. NDUFA4 silencing hinders NF-κB signaling activation and consequently attenuates inflammatory responses. Collectively, our findings have established the C15ORF48/miR-147-NDUFA4 molecular axis as an indispensable regulator of gut homeostasis, bridging mitochondrial metabolism and inflammation.


Assuntos
Metabolismo Energético , Microbioma Gastrointestinal , Inflamação , MicroRNAs , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , Camundongos , Metabolismo Energético/genética , Humanos , Inflamação/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Colite/metabolismo , Colite/microbiologia , Colite/genética , Colite/induzido quimicamente , NF-kappa B/metabolismo , Disbiose/metabolismo , Disbiose/microbiologia , Transdução de Sinais , Camundongos Endogâmicos C57BL , Doenças Inflamatórias Intestinais/metabolismo , Doenças Inflamatórias Intestinais/microbiologia , Doenças Inflamatórias Intestinais/genética
2.
Nat Chem Biol ; 20(4): 512-520, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37932527

RESUMO

Short prokaryotic Ago accounts for most prokaryotic Argonaute proteins (pAgos) and is involved in defending bacteria against invading nucleic acids. Short pAgo associated with TIR-APAZ (SPARTA) has been shown to oligomerize and deplete NAD+ upon guide-mediated target DNA recognition. However, the molecular basis of SPARTA inhibition and activation remains unknown. In this study, we determined the cryogenic electron microscopy structures of Crenotalea thermophila SPARTA in its inhibited, transient and activated states. The SPARTA monomer is auto-inhibited by its acidic tail, which occupies the guide-target binding channel. Guide-mediated target binding expels this acidic tail and triggers substantial conformational changes to expose the Ago-Ago dimerization interface. As a result, SPARTA assembles into an active tetramer, where the four TIR domains are rearranged and packed to form NADase active sites. Together with biochemical evidence, our results provide a panoramic vision explaining SPARTA auto-inhibition and activation and expand understanding of pAgo-mediated bacterial defense systems.


Assuntos
Proteínas Argonautas , Bactérias , Proteínas Argonautas/genética , Proteínas Argonautas/química , Proteínas Argonautas/metabolismo , Bactérias/genética , Células Procarióticas/metabolismo , DNA/genética , Ligação Proteica
3.
Appl Microbiol Biotechnol ; 108(1): 99, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38204135

RESUMO

Ectomycorrhizal fungi (EMF) can form symbiotic relationships with plants, aiding in plant growth by providing access to nutrients and defense against phytopathogenic fungi. In this context, factors such as plant assemblages and soil properties can impact the interaction between EMF and phytopathogenic fungi in forest soil. However, there is little understanding of how these fungal interactions evolve as forests move through succession stages. In this study, we used high-throughput sequencing to investigate fungal communities in young, intermediate, and old subtropical forests. At the genus level, EMF communities were dominated by Sebacina, Russula, and Lactarius, while Mycena was the most abundant genus in pathogenic fungal communities. The relative abundances of EMF and phytopathogenic fungi in different stages showed no significant difference with the regulation of different factors. We discovered that interactions between phytopathogenic fungi and EMF maintained a dynamic balance under the influence of the differences in soil quality attributed to each forest successional stage. The community composition of phytopathogenic fungi is one of the strong drivers in shaping EMF communities over successions. In addition, the EMF diversity was significantly related to plant diversity, and these relationships varied among successional stages. Despite the regulation of various factors, the positive relationship between the diversity of phytopathogenic fungi and EMF remained unchanged. However, there is no significant difference in the ratio of the abundance of EMF and phytopathogenic fungi over the course of successions. These results will advance our understanding of the biodiversity-ecosystem functioning during forest succession. KEY POINTS: •Community composition of both EMF and phytopathogenic fungi changed significantly over forest succession. •Phytopathogenic fungi is a key driver in shaping EMF community. •The effect of plant Shannon's diversity on EMF communities changed during the forest aging process.


Assuntos
Agaricales , Micobioma , Micorrizas , Ecossistema , Florestas , Solo
4.
Nucleic Acids Res ; 50(4): 2223-2239, 2022 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-35104889

RESUMO

N 6-Threonylcarbamoyladenosine (t6A) is a universal and pivotal tRNA modification. KEOPS in eukaryotes participates in its biogenesis, whose mutations are connected with Galloway-Mowat syndrome. However, the tRNA substrate selection mechanism by KEOPS and t6A modification function in mammalian cells remain unclear. Here, we confirmed that all ANN-decoding human cytoplasmic tRNAs harbor a t6A moiety. Using t6A modification systems from various eukaryotes, we proposed the possible coevolution of position 33 of initiator tRNAMet and modification enzymes. The role of the universal CCA end in t6A biogenesis varied among species. However, all KEOPSs critically depended on C32 and two base pairs in the D-stem. Knockdown of the catalytic subunit OSGEP in HEK293T cells had no effect on the steady-state abundance of cytoplasmic tRNAs but selectively inhibited tRNAIle aminoacylation. Combined with in vitro aminoacylation assays, we revealed that t6A functions as a tRNAIle isoacceptor-specific positive determinant for human cytoplasmic isoleucyl-tRNA synthetase (IARS1). t6A deficiency had divergent effects on decoding efficiency at ANN codons and promoted +1 frameshifting. Altogether, our results shed light on the tRNA recognition mechanism, revealing both commonality and diversity in substrate recognition by eukaryotic KEOPSs, and elucidated the critical role of t6A in tRNAIle aminoacylation and codon decoding in human cells.


Assuntos
Eucariotos , RNA de Transferência de Isoleucina , Adenosina/genética , Animais , Códon , Eucariotos/genética , Células HEK293 , Humanos , Mamíferos/genética , Conformação de Ácido Nucleico , RNA de Transferência/genética , RNA de Transferência de Metionina
5.
Nucleic Acids Res ; 50(7): 4012-4028, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35357504

RESUMO

METTL8 has recently been identified as the methyltransferase catalyzing 3-methylcytidine biogenesis at position 32 (m3C32) of mitochondrial tRNAs. METTL8 also potentially participates in mRNA methylation and R-loop biogenesis. How METTL8 plays multiple roles in distinct cell compartments and catalyzes mitochondrial tRNA m3C formation remain unclear. Here, we discovered that alternative mRNA splicing generated several isoforms of METTL8. One isoform (METTL8-Iso1) was targeted to mitochondria via an N-terminal pre-sequence, while another one (METTL8-Iso4) mainly localized to the nucleolus. METTL8-Iso1-mediated m3C32 modification of human mitochondrial tRNAThr (hmtRNAThr) was not reliant on t6A modification at A37 (t6A37), while that of hmtRNASer(UCN) critically depended on i6A modification at A37 (i6A37). We clarified the hmtRNAThr substrate recognition mechanism, which was obviously different from that of hmtRNASer(UCN), in terms of requiring a G35 determinant. Moreover, SARS2 (mitochondrial seryl-tRNA synthetase) interacted with METTL8-Iso1 in an RNA-independent manner and modestly accelerated m3C modification activity. We further elucidated how nonsubstrate tRNAs in human mitochondria were efficiently discriminated by METTL8-Iso1. In summary, our results established the expression pattern of METTL8, clarified the molecular basis for m3C32 modification by METTL8-Iso1 and provided the rationale for the involvement of METTL8 in tRNA modification, mRNA methylation or R-loop biogenesis.


Assuntos
Metiltransferases/metabolismo , Mitocôndrias/metabolismo , RNA de Transferência , Processamento Alternativo , Humanos , Metiltransferases/genética , Mitocôndrias/genética , RNA Mensageiro , RNA de Transferência/genética , RNA de Transferência/metabolismo , RNA de Transferência de Treonina/genética
6.
Sensors (Basel) ; 23(11)2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37299778

RESUMO

With the gradual development of and improvement in earthquake early warning systems (EEWS), more accurate real-time seismic intensity measurements (IMs) methods are needed to assess the impact range of earthquake intensities. Although traditional point source warning systems have made some progress in terms of predicting earthquake source parameters, they are still inadequate at assessing the accuracy of IMs predictions. In this paper, we aim to explore the current state of the field by reviewing real-time seismic IMs methods. First, we analyze different views on the ultimate earthquake magnitude and rupture initiation behavior. Then, we summarize the progress of IMs predictions as they relate to regional and field warnings. The applications of finite faults and simulated seismic wave fields in IMs predictions are analyzed. Finally, the methods used to evaluate IMs are discussed in terms of the accuracy of the IMs measured by different algorithms and the cost of alerts. The trend of IMs prediction methods in real time is diversified, and the integration of various types of warning algorithms and of various configurations of seismic station equipment in an integrated earthquake warning network is an important development trend for future EEWS construction.


Assuntos
Terremotos , Algoritmos , Cognição
7.
J Ethn Subst Abuse ; : 1-16, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37261934

RESUMO

Previous studies on social contract reasoning of male substance abusers only examined individuals who are using drugs, and most of them compared social contract and nonsocial contract reasoning, and paid less attention to the characteristics of social contract reasoning of substance abusers during withdrawal. In addition, there is little research on the difference between the standard social contract rules and the switched social contract rules. To further explore this issue, experiment 1 examined the differences between 110 male substance abusers' conditional reasoning for descriptive and social contract rules; Experiment 2 examined the differences between 110 other male substance abusers' conditional reasoning for standard and switched social contracts. Results: (1) for male substance abusers, the performance of social contract conditional reasoning is significantly better than descriptive conditional reasoning; (2) the performance of standard social contract rules is significantly better than that of switched social contract rules.

8.
Nucleic Acids Res ; 48(12): 6445-6457, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32484512

RESUMO

The accuracy in pairing tRNAs with correct amino acids by aminoacyl-tRNA synthetases (aaRSs) dictates the fidelity of translation. To ensure fidelity, multiple aaRSs developed editing functions that remove a wrong amino acid from tRNA before it reaches the ribosome. However, no specific mechanism within an aaRS is known to handle the scenario where a cognate amino acid is mischarged onto a wrong tRNA, as exemplified by AlaRS mischarging alanine to G4:U69-containing tRNAThr. Here, we report that the mischargeable G4:U69-containing tRNAThr are strictly conserved in vertebrates and are ubiquitously and abundantly expressed in mammalian cells and tissues. Although these tRNAs are efficiently mischarged, no corresponding Thr-to-Ala mistranslation is detectable. Mistranslation is prevented by a robust proofreading activity of ThrRS towards Ala-tRNAThr. Therefore, while wrong amino acids are corrected within an aaRS, a wrong tRNA is handled in trans by an aaRS cognate to the mischarged tRNA species. Interestingly, although Ala-tRNAThr mischarging is not known to occur in bacteria, Escherichia coli ThrRS also possesses robust cross-editing ability. We propose that the cross-editing activity of ThrRS is evolutionarily conserved and that this intrinsic activity allows G4:U69-containing tRNAThr to emerge and be preserved in vertebrates to have alternative functions without compromising translational fidelity.


Assuntos
Aminoacil-tRNA Sintetases/metabolismo , Edição de RNA , RNA de Transferência/metabolismo , Alanina/genética , Animais , Evolução Molecular , Células HEK293 , Humanos , RNA de Transferência/genética , Treonina/genética , Vertebrados/genética
9.
J Appl Clin Med Phys ; 23(12): e13746, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35946866

RESUMO

PURPOSE: Diabetic retinopathy (DR) is one of the most serious complications of diabetes, which is a kind of fundus lesion with specific changes. Early diagnosis of DR can effectively reduce the visual damage caused by DR. Due to the variety and different morphology of DR lesions, automatic classification of fundus images in mass screening can greatly save clinicians' diagnosis time. To alleviate these problems, in this paper, we propose a novel framework-graph attentional convolutional neural network (GACNN). METHODS AND MATERIALS: The network consists of convolutional neural network (CNN) and graph convolutional network (GCN). The global and spatial features of fundus images are extracted by using CNN and GCN, and attention mechanism is introduced to enhance the adaptability of GCN to topology map. We adopt semi-supervised method for classification, which greatly improves the generalization ability of the network. RESULTS: In order to verify the effectiveness of the network, we conducted comparative experiments and ablation experiments. We use confusion matrix, precision, recall, kappa score, and accuracy as evaluation indexes. With the increase of the labeling rates, the classification accuracy is higher. Particularly, when the labeling rate is set to 100%, the classification accuracy of GACNN reaches 93.35%. Compared with DenseNet121, the accuracy rate is improved by 6.24%. CONCLUSIONS: Semi-supervised classification based on attention mechanism can effectively improve the classification performance of the model, and attain preferable results in classification indexes such as accuracy and recall. GACNN provides a feasible classification scheme for fundus images, which effectively reduces the screening human resources.


Assuntos
Retinopatia Diabética , Redes Neurais de Computação , Humanos , Fundo de Olho , Retinopatia Diabética/diagnóstico por imagem
10.
Sensors (Basel) ; 22(22)2022 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-36433365

RESUMO

Using sensors embedded in smartphones to study earthquake early warning (EEW) technology can effectively reduce the high construction and maintenance costs of traditional EEW systems. However, due to the impact of human activities, it is very difficult to accurately detect seismic events recorded on mobile phones. In this paper, to improve the detection accuracy of earthquakes on mobile phones, we investigated the suitability of different types of neural network models in seismic event detection. Firstly, we collected three-component acceleration records corresponding to human activities in various scenarios such as walking, running, and cycling through our self-developed mobile application. Combined with traditional strong-motion seismic event records fusing typical mobile phone accelerometer self-noise, all records were used for establishing the training and testing dataset. Finally, two types of neural network models, fully connected and convolutional neural networks, were trained, validated, and tested. The results showed that the accuracy rates of the neural network models were all over 98%, and the precision rate for seismic events and the recall rate for non-earthquake events could both reach 99%, indicating that the introduction of neural networks into the earthquake recognition on smartphones can significantly enhance the accuracy of seismic event recognition. Therefore, we can exceedingly reduce the amount of data transmitted to the processing server, further lowering the load on the server processor and effectively increasing the lead time at each target site for an EEW system.


Assuntos
Terremotos , Smartphone , Humanos , Algoritmos , Redes Neurais de Computação , Reconhecimento Psicológico
11.
Molecules ; 27(19)2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36235209

RESUMO

To extend the application range of L-asparaginase in food pre-processing, the thermostability improvement of the enzyme is essential. Herein, two non-conserved cysteine residues with easily oxidized free sulfhydryl groups, Cys8 and Cys283, of Acinetobacter soli L-asparaginase (AsA) were screened out via consensus design. After saturation mutagenesis and combinatorial mutation, the mutant C8Y/C283Q with highly improved thermostability was obtained with a half-life of 361.6 min at 40 °C, an over 34-fold increase compared with that of the wild-type. Its melting temperature (Tm) value reaches 62.3 °C, which is 7.1 °C higher than that of the wild-type. Molecular dynamics simulation and structure analysis revealed the formation of new hydrogen bonds of Gln283 and the aromatic interaction of Tyr8 formed with adjacent residues, resulting in enhanced thermostability. The improvement in the thermostability of L-asparaginase could efficiently enhance its effect on acrylamide inhibition; the contents of acrylamide in potato chips were efficiently reduced by 86.50% after a mutant C8Y/C283Q treatment, which was significantly higher than the 59.05% reduction after the AsA wild-type treatment. In addition, the investigation of the mechanism behind the enhanced thermostability of AsA could further direct the modification of L-asparaginases for expanding their clinical and industrial applications.


Assuntos
Asparaginase , Cisteína , Acinetobacter , Acrilamida , Asparaginase/química , Asparaginase/genética , Estabilidade Enzimática , Cinética , Temperatura
12.
Appl Microbiol Biotechnol ; 105(13): 5643-5655, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34160646

RESUMO

Brevibacillins are broad-spectrum cationic antimicrobial lipopeptides produced by Brevibacillus laterosporus fmb70 CGMCC 18426. The antibacterial mode of brevibacillins against Salmonella typhimurium CICC 21493 was investigated by quantum chemistry calculation in this study. The addition of LPS, Mg2+, and Ca2+ partially reduced the antimicrobial activity of brevibacillin and brevibacillin V against S. typhimurium, which indicated that the two cationic lipopeptides could bind to LPS and displaced the divalent cations on the LPS network. Release of LPS from S. typhimurium by brevibacillin and brevibacillin V resulted in destroying the dense LPS network and increasing the permeability of the outer membrane. Quantum chemistry calculation analysis revealed that Lys7 is the most critical amino acid residue to destroy the outer membrane. The total average N-H charge difference of the three protonated amino groups (Orn3-NH3, Lys7-NH3, and Lys10-NH3) determined the ability of brevibacillin V to bind LPS stronger than brevibacillin. Calcein complete leakage from liposomes and release of DiSC3-5 from the cytoplasmic membrane (CM) indicated that brevibacillin and brevibacillin V may destroy the CM. Brevibacillin and brevibacillin V exhibited their antimicrobial activities through membrane damages, where the OM permeability with high concentration of 64-256 µg/mL and membrane damage of CM with a low concentration of 4 µg/mL. Our finding might be helpful to understand the broad-spectrum antimicrobial mechanism of cationic lipopeptide and to design the novel antimicrobial peptide. KEY POINTS: • Brevibacillin V had stronger affinity for LPS than brevibacillin. • The N-H charge difference was the key of the difference in the affinity to LPS. • Brevibacillins inhibited Salmonella by displacing the divalent cations on the LPS.


Assuntos
Anti-Infecciosos , Lipopeptídeos , Antibacterianos/farmacologia , Brevibacillus , Lipopeptídeos/farmacologia , Lipopolissacarídeos , Salmonella typhimurium
13.
J Sci Food Agric ; 101(1): 229-239, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32627181

RESUMO

BACKGROUND: Synthetic fungicides are most commonly used for controlling postharvest disease of fruit, although they can cause the emergence of drug-resistant strains, environmental pollution and fruit safety issues. Bacillomycin D (BD), a novel antifungal lipopeptide, and chitosan (CTS) are applied for the preservation of cherry tomato. RESULTS: The combination of BD and CTS showed an additive inhibition on the growth of Rhizopus stolonifer and Botrytis cinerea compared to that of its individual compound. In addition, BD + CTS reduced the incidence of soft rot and gray mold in cherry tomato caused by R. stolonifer and B. cinerea, respectively. Tomato treated with BD + CTS exhibited a lower weight loss and higher firmness and higher contents of total soluble solids, titratable acidity and ascorbic acid compared to those treated with sterile water (control). The kinetics models demonstrated that the shelf life of cherry tomato treated with BD + CTS could be extended by approximately 15 days longer than the control. CONCLUSION: The utilization of BD + CTS provided a novel strategy for reducing postharvest fungal rot and maintaining the storage quality of cherry tomato. © 2020 Society of Chemical Industry.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Botrytis/efeitos dos fármacos , Quitosana/farmacologia , Conservação de Alimentos/métodos , Fungicidas Industriais/farmacologia , Rhizopus/efeitos dos fármacos , Solanum lycopersicum/microbiologia , Botrytis/crescimento & desenvolvimento , Sinergismo Farmacológico , Frutas/química , Frutas/microbiologia , Solanum lycopersicum/química , Doenças das Plantas/microbiologia , Rhizopus/crescimento & desenvolvimento
14.
Appl Microbiol Biotechnol ; 104(8): 3529-3540, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32103313

RESUMO

Malassezia globosa is an opportunistic pathogen that causes various skin disorders, which disturbs people's life all the time, and conventional drugs are not completely satisfactory. Bacillomycin D (BD), an antifungal lipopeptide, could inhibit various fungi growth. However, the reports about its effect on M. globosa were not found yet. In this study, we showed that BD and BD-C16 (fatty acid chain had sixteen carbon atoms) completely inhibited growth of M. globosa at concentration of 64 µg/ml in 15 h, which was confirmed with the observation of irregular morphological change of M. globosa treated with BD. Significantly, the study on the working mechanism showed that BD induced cell death by changing cell membrane permeability and thus promoting the release of cellular contents, which may be mediated by the interaction between BD and ergosterol from membrane. Further study showed that BD reduced the overall content of cellular sterol, and interestingly, the expression of some genes involved in membrane and ergosterol synthesis were significantly upregulated, which was likely to be a feedback regulation. Besides, we found that BD had additive and synergistic effects with ketoconazole and amphotericin B, respectively, on inhibition of M. globosa, suggesting that combination use of BD with other commercial drugs could be a promising strategy to relieve skin disorders caused by M. globosa. KEY POINTS: • BD could efficiently inhibit the growth of M. globosa. • BD increases cell membrane permeability and thus promotes the release of cellular contents. • BD has additive or synergistic effect with other antifungal drugs.


Assuntos
Antifúngicos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Membrana Celular/efeitos dos fármacos , Malassezia/efeitos dos fármacos , Malassezia/crescimento & desenvolvimento , Ergosterol/farmacologia , Testes de Sensibilidade Microbiana , Sorbitol/farmacologia
15.
Int J Mol Sci ; 21(15)2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32752130

RESUMO

The eukaryotic and archaeal translation factor IF5A requires a post-translational hypusine modification, which is catalyzed by deoxyhypusine synthase (DHS) at a single lysine residue of IF5A with NAD+ and spermidine as cofactors, followed by hydroxylation to form hypusine. While human DHS catalyzed reactions have been well characterized, the mechanism of the hypusination of archaeal IF5A by DHS is not clear. Here we report a DHS structure from Pyrococcus horikoshii OT3 (PhoDHS) at 2.2 Å resolution. The structure reveals two states in a single functional unit (tetramer): two NAD+-bound monomers with the NAD+ and spermidine binding sites observed in multi-conformations (closed and open), and two NAD+-free monomers. The dynamic loop region V288-P299, in the vicinity of the active site, adopts different positions in the closed and open conformations and is disordered when NAD+ is absent. Combined with NAD+ binding analysis, it is clear that PhoDHS can exist in three states: apo, PhoDHS-2 equiv NAD+, and PhoDHS-4 equiv NAD+, which are affected by the NAD+ concentration. Our results demonstrate the dynamic structure of PhoDHS at the NAD+ and spermidine binding site, with conformational changes that may be the response to the local NAD+ concentration, and thus fine-tune the regulation of the translation process via the hypusine modification of IF5A.


Assuntos
Oxirredutases atuantes sobre Doadores de Grupo CH-NH/ultraestrutura , Fatores de Iniciação de Peptídeos/ultraestrutura , Processamento de Proteína Pós-Traducional/genética , Pyrococcus horikoshii/ultraestrutura , Sítios de Ligação/genética , Cristalografia por Raios X , Eucariotos/genética , Eucariotos/metabolismo , Lisina/análogos & derivados , Lisina/química , Lisina/genética , Lisina/metabolismo , NAD/química , NAD/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/química , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Fatores de Iniciação de Peptídeos/química , Fatores de Iniciação de Peptídeos/genética , Conformação Proteica , Pyrococcus horikoshii/enzimologia , Espermidina/química , Espermidina/metabolismo
16.
Biochem Biophys Res Commun ; 519(1): 186-191, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31492496

RESUMO

In the process of eukaryotic translation, the formation of preinitiation complex 43S, which consists of a 40S subunit, the eIF2-GTP-Met-tRNAiMet ternary complex, eIF3, eIF1, eIF1A, and eIF5, is essential for translational quality control. Of those factors, eIF5 promotes the hydrolysis of eIF2-bound GTP to release eIF2-GDP in the complex for the recycling of eIF2. eIF5 appears to bind to the ß subunit of eIF2 (eIF2ß) via an interaction between aromatic/acidic residue-rich regions (AA-boxes) in the C-terminal domain of eIF5 (eIF5CTD) and three lysine clusters (K-boxes) in the N-terminal domain of eIF2ß (eIF2ßNTD). However, the details of this interaction are unclear, due to the lack of a structure for the eIF5-eIF2ß complex, and the unavailability of an intact structure of eIF5, in which the AA-boxes are always disordered, with high flexibility. In this study, we solved two crystal structures of eIF5CTD from Candida albicans, which for the first time showed the AA-box2 of eIF5 presenting as an ordered helical structure. The structures exhibited different arrangements of AA-box2 under different pH values, which may reflect the dynamic nature of the interactions of eIF5CTD, and eIF2ßNTD in the preinitiation complex.


Assuntos
Candida albicans/metabolismo , Fator de Iniciação 5 em Eucariotos/química , Fator de Iniciação 5 em Eucariotos/metabolismo , Sequência de Aminoácidos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Homologia Estrutural de Proteína , Relação Estrutura-Atividade , Difração de Raios X
17.
Cell Mol Neurobiol ; 37(5): 817-829, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27581683

RESUMO

Spinal cord injury (SCI) often causes neurological deficits with poor recovery; the treatment, however, is far from satisfaction, and the mechanisms remain unclear. Using immunohistochemistry and western blotting analysis, we found α-synuclein (SNCA) was significantly up-regulated in the spinal caudal segment of rats subjected to spinal cord transection at 3 days post-operation. Moreover, the role of SNCA on neuronal growth and apoptosis in vitro was determined by using overexpressing and interfering SNCA recombined plasmid vectors, and the underlying mechanism was detected by QRT-PCR and western blotting. Spinal neurons transfected with SNCA-shRNA lentivirus gave rise to an optimal neuronal survival, while it results in cell apoptosis in SNCA-ORF group. In molecular level, SNCA silence induced the up-regulation of CNTF and down-regulation of Caspase7/9. Together, endogenous SNCA plays a crucial role in spinal neuronal survival, in which the underlying mechanism may be linked to the regulation both apoptotic genes (Caspase7/9) and CNTF. The present findings therefore provide novel insights into the role of SNCA in spinal cord and associated mechanism, which may provide novel cue for the treatment of SCI in future clinic trials.


Assuntos
Apoptose , Fator Neurotrófico Ciliar/metabolismo , Medula Espinal/metabolismo , Medula Espinal/patologia , alfa-Sinucleína/metabolismo , Animais , Antígenos Nucleares/metabolismo , Sobrevivência Celular , Modelos Animais de Doenças , Feminino , Lentivirus/metabolismo , Fatores de Crescimento Neural/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Fases de Leitura Aberta/genética , RNA Interferente Pequeno/metabolismo , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia , Transfecção , Montagem de Vírus
18.
Neurochem Res ; 41(10): 2585-2597, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27278760

RESUMO

Spinal cord injury (SCI), a severe health problem in worldwide, was commonly associated with functional disability and reduced quality of life. As the expression of brain-derived neurotrophic factor (BDNF) was substantial event in injured spinal cord, we hypothesized whether BDNF-overexpression could be in favor of the recovery of both sensory function and hindlimb function after SCI. By using BDNF-overexpression transgene mice [CMV-BDNF 26 (CB26) mice] we assessed the role of BDNF on the recovery of neurological behavior in spinal cord transection (SCT) model. BMS score and tail-flick test was performed to evaluate locomotor function and sensory function, respectively. Immunohistochemistry was employed to detect the location and the expression of BDNF, NeuN, 5-HT, GAP-43, GFAP as well as CGRP, and the level of p-AKT and AKT were examined through western blot analysis. BDNF overexpressing resulted in significant locomotor functional recovery from 21 to 28 days after SCT, compared with wild type (WT)+SCT group. Meanwhile, the NeuN, 5-HT and GAP-43 positive cells were markedly increased in ventral horn in BDNF overexpression animals, compared with WT mice with SCT. Moreover, the crucial molecular signal, p-AKT/AKT has been largely up-regulated, which is consistent with the improvement of locomotor function. However, in this study, thermal hyperpathia encountered in sham (CB26) group and WT+SCT mice and further aggravated in CB26 mice after SCT. Also, following SCT, the significant augment of positive-GFAP astrocytes and CGRP fibers were found in WT+SCT mice, and further increase was seen in BDNF over-expression transgene mice. BDNF-overexpression may not only facilitate the recovery of locomotor function via AKT pathway, but also contributed simultaneously to thermal hyperalgesia after SCT.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Recuperação de Função Fisiológica/fisiologia , Transdução de Sinais/fisiologia , Traumatismos da Medula Espinal/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Modelos Animais de Doenças , Membro Posterior/metabolismo , Membro Posterior/fisiopatologia , Hiperalgesia/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Atividade Motora/fisiologia , Medula Espinal/metabolismo , Traumatismos da Medula Espinal/fisiopatologia
19.
Hu Li Za Zhi ; 63(4): 70-9, 2016 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-27492297

RESUMO

BACKGROUND: Long-term care institutions have become an option for older people who are dependent in daily living. However, insufficient attention has been focused on assessing the life satisfaction of those currently residing in these institutions in Taiwan. Previous research indicates that group reminiscence may improve the life satisfaction of older adults. However, there is currently no consensus regarding the implementation and evaluation of reminiscence interventions. PURPOSE: To examine the effect of a structured group reminiscence protocol on the life satisfaction of institutionalized older adults. METHODS: The study used a quasi-experimental design. A total of 48 older adults were conveniently recruited from two long-term care institutions in southern Taiwan. The experimental group (n = 23) received 8 weeks of structured-group reminiscence for 40 minutes weekly, while the control group (n = 25) received routine care from the institution. Both groups were evaluated using a life-satisfaction questionnaire before and after the intervention and again four weeks later. RESULTS: Life satisfaction scores were statistically similar on the pre-test and significantly different on both post-test questionnaires for the two groups. The scores for the experimental and control groups were pre-test: 24.22 vs 23.36 (p = .063); post-test I: 27.22 vs 23.32 (p < .001); and post-test II: 26.43 vs 23.00 (p < .001). The mean post-test scores for the experimental group were significantly higher than the pre-test score (p < .001). The generalized estimating equation test showed that the overall score of life satisfaction for the experimental group increased by 0.85-points (p = .042) more than the control group, which is a significant difference. CONCLUSIONS / IMPLICATIONS FOR PRACTICE: The results support that the 8-week structured group reminiscence protocol effectively enhances life satisfaction in older adults. The results of this study may be referenced in the continuing education of nurses working in long-term care institutions in the context of helping nurses organize, facilitate, and evaluate this protocol.


Assuntos
Institucionalização , Satisfação Pessoal , Psicoterapia de Grupo/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino
20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(8): 2312-5, 2015 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-26672315

RESUMO

Basalt is the raw material of basalt fiber. The content of FeO and Fe2O3 has a great impact on the properties of basalt fibers. ICP-OES and dichromate method were used to test total Fe and Fe(2+) in basalt. Suitable instrument parameters and analysis lines of Fe were chosen for ICP-OES. The relative standard deviation (RSD) of ICP-OES is 2.2%, and the recovery is in the range of 98%~101%. The method shows simple, rapid and highly accurate for determination of total Fe and Fe(2+) in basalt. The RSD of ICP-OES and dichromate method is 0.42% and 1.4%, respectively.

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