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1.
ACS Appl Mater Interfaces ; 16(4): 4679-4688, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38241712

RESUMO

Improving the sulfur content in the cathode is essential for achieving high-energy-density all-solid-state lithium-sulfur batteries (ASSLSBs). However, the complex multiinterfaces, akin to the short wooden planks that consist of the cask, severely limit the performance of ASSLSBs with high sulfur content. Since singular approaches fail to optimize these interfaces simultaneously, we propose a synergistic approach using a dual-doped sulfide solid electrolyte (Y2S3 and LiI) and an SbSn alloy sulfur host in this work. The incorporation of Y2S3 in the solid electrolyte serves to improve the electrolyte-electrolyte interfaces and enhance the ionic conductivity, while the inclusion of LiI helps stabilize the electrolyte-anode interface and suppress dendrite formation. Meanwhile, the SbSn alloy sulfur host facilitates the transfer of Li+ at the electrolyte-cathode interfaces. Consequently, the solid-solid interfaces are significantly improved, leading to impressive specific capacities in ASSLSBs with high sulfur content (>44% in the cathode composite) at room temperature (1163.5 mAh g-1) and at 60 °C (1408.7 mAh g-1) during the 50th cycle at 0.05C. This work presents a promising strategy for achieving practical high-performance ASSLSBs.

2.
Br J Cancer ; 129(8): 1238-1250, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37626264

RESUMO

BACKGROUND: Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibition yields differential cellular responses in multiple tumor models due to redundancy in cell cycle. We investigate whether the differential requirements of CDKs in multiple cell lines function as determinant of response to pharmacological agents that target these kinases. METHODS: We utilized proteolysis-targeted chimeras (PROTACs) that are conjugated with palbociclib (Palbo-PROTAC) to degrade both CDK4 and CDK6. FN-POM was synthesized by chemically conjugating pomalidomide moiety with a multi-kinase inhibitor, FN-1501. Patient derived PDAC organoids and PDX model were utilized to investigate the effect of FN-POM in combination with palbociclib. RESULTS: Palbo-PROTAC mediates differential impact on cell cycle in different tumor models, indicating that the dependencies to CDK4 and 6 kinases are heterogenous. Cyclin E overexpression uncouples cell cycle from CDK4/6 and drives resistance to palbo-PROTAC. Elevated expression of P16INK4A antagonizes PROTAC-mediated degradation of CDK4 and 6. FN-POM degrades cyclin E and CDK2 and inhibits cell cycle progression in P16INK4A-high tumor models. Combination of palbociclib and FN-POM cooperatively inhibit tumor cell proliferation via RB activation. CONCLUSION: Resistance to CDK4/6 inhibition could be overcome by pharmacologically limiting Cyclin E/CDK2 complex and proves to be a potential therapeutic approach.

3.
Mol Neurobiol ; 60(11): 6294-6306, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37442859

RESUMO

FERM, RhoGEF, and Pleckstrin domain protein (FARP) mediated RhoGTPase pathways are involved in diverse biological processes, such as neuronal development and tumorigenesis. However, little is known about their role in neural regeneration. We uncovered for the first time that FARP-Rac1 signaling plays an important role in neural regeneration in Dugesia japonica, a planarian that possesses unparalleled regenerative capacities. The planarian FARP homolog DjFARP was primarily expressed in both intact and regenerating brain and pharynx tissue. Functional studies suggested that downregulation of DjFARP with dsRNA in Dugesia japonica led to smaller brain sizes, defects in brain lateral branches, and loss of cholinergic, GABAergic, and dopaminergic neurons in both intact and regenerating animals. Moreover, the Rho GTPase DjRac1 was shown to play a similar role in neural regeneration and maintenance. Rac1 activation assay showed that DjFARP acts as a guanine nucleotide exchange factor (GEF) for DjRac1. Together, these findings indicate that the brain defects seen in DjFARP knockdown animals may be attributable to DjRac1 inactivation. In conclusion, our study demonstrated that DjFARP-DjRac1 signaling was required for the maintenance and proper regeneration of the brain in Dugesia japonica.

4.
Front Mol Neurosci ; 15: 988803, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36172263

RESUMO

Disturbances in the excitatory/inhibitory balance of brain neural circuits are the main source of encephalopathy during neurodevelopment. Changes in the function of neural circuits can lead to depolarization or repeat rhythmic firing of neurons in a manner similar to epilepsy. GABAergic neurons are inhibitory neurons found in all the main domains of the CNS. Previous studies suggested that DjCamkII and DjCaln play a crucial role in the regulation of GABAergic neurons during planarian regeneration. However, the mechanisms behind the regeneration of GABAergic neurons have not been fully explained. Herein, we demonstrated that DjCamkII and DjCaln were mutual negative regulation during planarian head regeneration. DjNFAT exerted feedback positive regulation on both DjCaln and DjCamkII. Whole-mount in situ hybridization (WISH) and fluorescence in situ hybridization (FISH) revealed that DjNFAT was predominantly expressed in the pharynx and parenchymal cells in intact planarian. Interestingly, during planarian head regeneration, DjNFAT was predominantly located in the newborn brain. Down-regulation of DjNFAT led to regeneration defects in the brain including regenerative brain became small and the lateral nerves cannot be regenerated completely, and a decreasein the number of GABAergic neurons during planarian head regeneration. These findings suggest that the feedback loop between DjCaln, DjCamkII, and DjNFAT is crucial for the formation of GABAergic neurons during planarian head regeneration.

5.
Int J Biol Macromol ; 209(Pt A): 1054-1064, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35452697

RESUMO

Freshwater planarian Dugesia japonica is an excellent model organism for investigating stem cell behavior during regeneration. Despite studies showing that numerous genetic factors are involved in regeneration, much more research is required to fully understand the molecular mechanisms that orchestrate regeneration. In this study, we identified an evolutionarily conserved gene DjPtpn11(DjShp2). DjPtpn11 transcripts are expressed in neoblasts and some differentiated cells, with a high expression at the newly formed blastema. Its silencing by RNA interference (RNAi) affected anterior regeneration and inhibited the regeneration of posterior regions, including cholinergic and serotonergic neuron regeneration. In adult planarians, DjPtpn11 knockdown did not affect neoblast survival and proliferation but might prevent the stem cell migration and differentiation through ERK signaling. DjPtpn11 was demonstrated to be necessary for the anterior blastema cell differentiation partially via regulating ERK-DjMkpA activity. DjPtpn11 also influenced posterior specification via DjIslet, suggesting that DjPtpn11 may be involved in regulating the Wnt signaling pathway during the development of posterior blastema. Together, these data identified that DjPtpn11 is an essential modulator for the regeneration of planarians, and it may influence the appropriate differentiation of blastema cells.


Assuntos
Planárias , Animais , Diferenciação Celular/genética , Planárias/genética , Interferência de RNA , Transdução de Sinais/fisiologia , Células-Tronco
6.
ACS Appl Mater Interfaces ; 14(1): 1212-1221, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-34967595

RESUMO

All-solid-state lithium-sulfur batteries (ASSLSBs) have become a promising candidate because of their high energy density and safety. To ensure the high utilization and electrochemical capacity of sulfur in all-solid-state batteries, both the electronic and ionic conductivities of the sulfur cathode should be as high as possible. In this work, an intercalation-conversion hybrid cathode is proposed by distributing sulfur evenly on electroactive niobium tungsten oxide (Nb18W16O93) and conductive carbon nanotubes (CNTs) for achieving high performance ASSLSBs. Herein, Nb18W16O93 shows good electrochemical lithium storage in the hybrid cathode, which could serve as an effective Li-ion/electron conductor for the conversion of sulfur in the discharge/charge processes to achieve a high utilization of sulfur. However, CNTs could further increase the electronic conductivity of the hybrid cathode by constructing good conductive frameworks and suppress the volumetric fluctuation during the interconversion of sulfur and Li2S. With this strategy, the S/Nb18W16O93/CNT cathode achieves a high sulfur utilization of 91% after one cycle activation with a high gravimetric capacity of 1526 mA h g-1. In addition, excellent rate performance is also obtained at 0.5 C with a reversible capacity of 1262 mA h g-1 after 1000 cycles. This work offers a new perspective to develop ASSLSBs.

7.
ACS Appl Mater Interfaces ; 13(29): 34477-34485, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34275286

RESUMO

Glass-ceramic sulfide solid electrolytes like Li7P3S11 are practicable propellants for safe and high-performance all-solid-state lithium-sulfur batteries (ASSLSBs); however, the stability and conductivity issues remain unsatisfactory. Herein, we propose a congener substitution strategy to optimize Li7P3S11 as Li7P2.9Sb0.1S10.75O0.25 via chemical bond and structure regulation. Specifically, Li7P2.9Sb0.1S10.75O0.25 is obtained by a Sb2O5 dopant to achieve partial Sb/P and O/S substitution. Benefiting from the strengthened oxysulfide structural unit of POS33- and P2OS64- with bridging oxygen atoms and a distorted lattice configuration of the Sb-S tetrahedron, the Li7P2.9Sb0.1S10.75O0.25 electrolyte exhibits prominent chemical stability and high ionic conductivity. Besides the improved air stability, the ionic conductivity of Li7P2.9Sb0.1S10.75O0.25 could reach 1.61 × 10-3 S cm-1 at room temperature with a wide electrochemical window of up to 5 V (vs Li/Li+), as well as good stability against Li and Li-In alloy anodes. Consequently, the ASSLSB with the Li7P2.9Sb0.1S10.75O0.25 electrolyte shows high discharge capacities of 1374.4 mAh g-1 (0.05C, 50th cycle) at room temperature and 1365.4 mAh g-1 (0.1C, 100th cycle) at 60 °C. The battery also presents remarkable rate performance (1158.3 mAh g-1 at 1C) and high Coulombic efficiency (>99.8%). This work provides a feasible technical route for fabricating ASSLSBs.

8.
Chem Soc Rev ; 50(17): 9794-9816, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34291273

RESUMO

Fluorescent dyes attached to kinase inhibitors (KIs) can be used to probe kinases in vitro, in cells, and in vivo. Ideal characteristics of the dyes vary with their intended applications. Fluorophores used in vitro may inform on kinase active site environments, hence the dyes used should be small and have minimal impact on modes of binding. These probes may have short wavelength emissions since blue fluorophores are perfectly adequate in this context. Thus, for instance, KI fragments that mimic nucleobases may be modified to be fluorescent with minimal perturbation to the kinase inhibitor structure. However, progressively larger dyes, that emit at longer wavelengths, are required for cellular and in vivo work. In cells, it is necessary to have emissions above autofluorescence of biomolecules, and near infrared dyes are needed to enable excitation and observation through tissue in vivo. This review is organized to describe probes intended for applications in vitro, in cells, then in vivo. The readers will observe that the probes featured tend to become larger and responsive to the near infared end of the spectrum as the review progresses. Readers may also be surprised to realize that relatively few dyes have been used for fluorophore-kinase inhibitor conjugates, and the area is open for innovations in the types of fluorophores used.


Assuntos
Corantes Fluorescentes , Neoplasias , Humanos , Neoplasias/tratamento farmacológico
9.
Biol Open ; 10(6)2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34184734

RESUMO

MicroRNAs (miRNAs) are a class of evolutionarily conserved small non-coding RNAs that regulate gene expression at the translation level in cell growth, proliferation and differentiation. In addition, some types of miRNAs have been proven to be key modulators of both CNS development and plasticity, such as let-7, miR-9 and miR-124. In this research, we found miR-8b acts as an important regulator involved in brain and eyespot regeneration in Dugesia japonica. miR-8b was highly conserved among species and was abundantly expressed in central nervous system. Here, we detected the expression dynamics of miR-8b by qPCR during the head regeneration of D. japonica. Knockdown miR-8b by anti-MIRs method caused severe defects of eyes and CNS. Our study revealed the evolutionary conserved role of miR-8b in the planarian regeneration process, and further provided more research ideas and available information for planarian miRNAs.


Assuntos
Encéfalo , Olho , Regulação da Expressão Gênica , Cabeça , MicroRNAs/genética , Planárias/fisiologia , Regeneração , Animais , Técnicas de Silenciamento de Genes , Fenótipo
10.
Dev Comp Immunol ; 121: 104097, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33831480

RESUMO

ß-Thymosin is a multifunctional peptide ubiquitously expressed in vertebrates and invertebrates. Many studies have found ß-thymosin is critical for wound healing, angiogenesis, cardiac repair, hair regrowth, and anti-fibrosis in vertebrates, and plays an important role in antimicrobial immunity in invertebrates. However, whether ß-thymosin participates in the regeneration of organisms is still poorly understood. In this study, we identified a ß-thymosin gene in Dugesia japonica which played an important role in stem cell proliferation and neuron regeneration during the tissue repair process in D. japonica. Sequencing analysis showed that ß-thymosin contained two conserved ß-thymosin domains and two actin-binding motifs, and had a high similarity with other ß-thymosins of invertebrates. In situ or fluorescence in situ hybridization analysis revealed that Djß-thymosin was co-localized with DjPiWi in the neoblast cells of intact adult planarians and the blastema of regenerating planarians, suggesting Djß-thymosin has a potential function of regeneration. Disruption Djß-thymosin by RNA interference results in a slightly curled up head of planarian and stem cell proliferation defects. Additionally, we found that, upon amputation, Djß-thymosin RNAi-treated animals had impaired regeneration ability, including impaired blastema formation, delayed eyespot formation, decreased brain area, and disrupted central CNS formation, implying Djß-thymosin is an essential regulator of stem cell proliferation and neuron regeneration.


Assuntos
Proteínas de Helminto/metabolismo , Regeneração Nervosa , Neurogênese , Planárias/fisiologia , Timosina/metabolismo , Animais , Proliferação de Células , Proteínas de Helminto/genética , Neurônios/fisiologia , Células-Tronco/fisiologia
11.
Dev Comp Immunol ; 116: 103914, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33137392

RESUMO

The powerful regenerative ability of planarians has long been a concern of scientists, but recently, their efficient immune system has attracted more and more attention from researchers. Gamma-interferon-inducible lysosomal thiol reductase (GILT) is related not only to antigen presentation but also to bacteria invasions. But the systematic studies are not yet to be conducted on the relationship between bacterial infection. Our study reveals for the first time that GILT of planarian (DjGILT) plays an essential role in the clearance of Gram-negative bacteria by conducting H2O2 concentration in planarians. In animals that DjGILT was silenced, it persisted for up to 9 days before all bacteria were cleared, compared with 6 days of the control group. When infected with E. coli and V. anguillarum, the level of H2O2 was significantly increased in DjGILT-silenced planarians, and concomitantly, mRNA level of C-type lectin DjCTL, which modulates agglutination and clearance efficiency of invading bacteria, was decreased. Further study showed that the decrease of H2O2 level led to a significant increase in DjCTL transcripts. Collectively, we proposed a mechanism model for the involvement of GILT gene in bacterial elimination. We have for the first time revealed the specific mechanism of GILT in innate immune response against bacterial infection.


Assuntos
Bactérias Gram-Negativas/imunologia , Proteínas de Helminto/imunologia , Interferon gama/farmacologia , Lisossomos/efeitos dos fármacos , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/imunologia , Planárias/imunologia , Sequência de Aminoácidos , Animais , Escherichia coli/imunologia , Escherichia coli/fisiologia , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/imunologia , Bactérias Gram-Negativas/fisiologia , Proteínas de Helminto/classificação , Proteínas de Helminto/genética , Interações Hospedeiro-Patógeno/imunologia , Peróxido de Hidrogênio/imunologia , Peróxido de Hidrogênio/metabolismo , Imunidade Inata/genética , Imunidade Inata/imunologia , Lisossomos/enzimologia , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/genética , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/metabolismo , Filogenia , Planárias/genética , Planárias/microbiologia , Homologia de Sequência de Aminoácidos , Compostos de Sulfidrila/metabolismo , Vibrio/imunologia , Vibrio/fisiologia
12.
Protein Pept Lett ; 28(6): 612-622, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33319655

RESUMO

Apoptosis, also named programmed cell death, is a highly conserved physiological mechanism. Apoptosis plays crucial roles in many life processes, such as tissue development, organ formation, homeostasis maintenance, resistance against external aggression, and immune responses. Apoptosis is regulated by many genes, among which Apoptosis Inhibitor-5 (API5) is an effective inhibitor, though the structure of API5 is completely different from the other known Inhibitors of Apoptosis Proteins (IAPs). Due to its high expression in many types of tumors, API5 has received extensive attention, and may be an effective target for cancer treatment. In order to comprehensively and systematically understand the biological roles of API5, we summarized the evolution and structure of API5 and its roles in anti-apoptosis in this review.


Assuntos
Proteínas Reguladoras de Apoptose , Apoptose , Proteínas Nucleares , Animais , Apoptose/genética , Apoptose/fisiologia , Humanos , Camundongos , Modelos Moleculares , Conformação Proteica , Ratos
13.
BMC Genomics ; 21(1): 876, 2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33287698

RESUMO

BACKGROUND: Planarians reliably regenerate all body parts after injury, including a fully functional head and central nervous system. But until now, the expression dynamics and functional role of miRNAs and other small RNAs during the process of head regeneration are not well understood. Furthermore, little is known about the evolutionary conservation of the relevant small RNAs pathways, rendering it difficult to assess whether insights from planarians will apply to other taxa. RESULTS: In this study, we applied high throughput sequencing to identify miRNAs, tRNA fragments and piRNAs that are dynamically expressed during head regeneration in Dugesia japonica. We further show that knockdown of selected small RNAs, including three novel Dugesia-specific miRNAs, during head regeneration induces severe defects including abnormally small-sized eyes, cyclopia and complete absence of eyes. CONCLUSIONS: Our findings suggest that a complex pool of small RNAs takes part in the process of head regeneration in Dugesia japonica and provide novel insights into global small RNA expression profiles and expression changes in response to head amputation. Our study reveals the evolutionary conserved role of miR-124 and brings further promising candidate small RNAs into play that might unveil new avenues for inducing restorative programs in non-regenerative organisms via small RNA mimics based therapies.


Assuntos
Planárias , Animais , Sistema Nervoso Central , Sequenciamento de Nucleotídeos em Larga Escala , Planárias/genética , RNA Interferente Pequeno/genética
14.
FASEB J ; 34(12): 16567-16580, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33094857

RESUMO

The growth and differentiation of neurons are critical events in the establishment of proper neuron connectivity and function. Planarians have a remarkable ability to completely regenerate a functional nervous system from a pluripotent stem cell population. Thus, planarians provide a powerful model to identify genes required for neuronal differentiation in vivo. The Wnt/Ca2+ signaling pathway is crucial for cancer development, arousing inflammatory responses, and neurodegeneration. We analyzed the expression patterns and RNAi phenotypes for members of the Wnt/Ca2+ signaling pathway in the planarian, Dugesia japonica. The expression of DjWnt5a, DjPLC-ß, DjCamKII, and DjCaln during regeneration was surprisingly similar and revealing in the regenerated brain. RNAi knockdown of DjWnt5a, DjPLC-ß, DjCamKII, and DjCaln led to defects in regenerated brains including brain partial deletions, incompact phenotypes at the posterior of the new brain, and lateral branches, which could not regenerate. Furthermore, the expressions of GAD and the number of GABAergic neurons decreased. Together, these results suggest that the Wnt/Ca2+ signaling pathway is required for GABAergic neuron regeneration.


Assuntos
Cálcio/metabolismo , Neurônios GABAérgicos/metabolismo , Neurônios GABAérgicos/fisiologia , Planárias/metabolismo , Planárias/fisiologia , Transdução de Sinais/fisiologia , Via de Sinalização Wnt/fisiologia , Animais , Encéfalo/metabolismo , Encéfalo/fisiologia , Diferenciação Celular/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Células-Tronco Pluripotentes/metabolismo , Células-Tronco Pluripotentes/fisiologia
15.
Biochem Biophys Res Commun ; 533(4): 1359-1365, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33059921

RESUMO

A small GTPase, RhoA, plays a variety of functions in the regulation of cellular and developmental events via its downstream effectors, including cytokinesis, cell migration, and phagocytosis. In this study, a novel RhoA-related gene from the planarian Dugesia japonica, DjRhoA, was cloned and characterized. The full-length cDNA of DjRhoA is 869 bp, and the open reading frame encodes a poly-peptide of 194 amino acids. Phylogenetic analysis revealed that DjRhoA clustered with another RhoA-related protein, DjRho2, and located on the base of phylogenetic tree. Whole-mount in situ hybridization results indicated that DjRhoA was expressed in the brain primordia and intestine during regeneration. Knockdown of DjRhoA induces defects in the brain and intestine. These results suggested that DjRhoA was responsible for the regeneration of brain and intestine in Dugesia japonica.


Assuntos
Encéfalo/fisiologia , Intestinos/fisiologia , Planárias/fisiologia , Regeneração/fisiologia , Proteína rhoA de Ligação ao GTP/genética , Animais , Expressão Gênica , Proteínas de Helminto/genética , Filogenia , Planárias/genética , Interferência de RNA , RNA Mensageiro/genética
16.
Cell Biosci ; 10: 111, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974004

RESUMO

BACKGROUND: Acting as a cellular cleaner by packaging and transporting defective proteins and organelles to lysosomes for breakdown, autophagic process is involved in the regulation of cell remodeling after cell damage or cell death in both vertebrate and invertebrate. In human, limitations on the regenerative capacity of specific tissues and organs make it difficult to recover from diseases. Comprehensive understanding on its mechanism within invertebrate have strong potential provide helpful information for challenging these diseases. METHOD: In this study, recent findings on the autophagy function in three invertebrates including planarian, hydra and leech with remarkable regenerative ability were summarized. Furthermore, molecular phylogenetic analyses of DjATGs and HvATGs were performed on these three invertebrates compared to that of Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Mus musculus and Homo sapiens. RESULTS: In comparison with Scerevisiae, C elegans, D melanogaster, M musculus and human, our analysis exhibits the following characteristics of autophagy and its function in regeneration within invertebrate. Phylogenetical analysis of ATGs revealed that most autophagy-related genes (ATGs) were highly similar to their homologs in other species, which indicates that autophagy is a highly conservative biological function in both vertebrate and invertebrate. Structurally, almost all the core amino acids necessary for the function of ATG8 in mammal were observed in invertebrate HvATG8s and DjATG8s. For instance, ubiquitin-like domain as a signature structure in each ATG8, was observed in all ATG8s in three invertebrates. Basically, autophagy plays a key role in the regulation of regeneration in planarian. DjATG8-2 and DjATG8-3 associated with mTOR signaling pathway are sophisticated in the invertebrate tissue/organ regeneration. Furthermore, autophagy is involved in the pathway of neutralization of toxic molecules input from blood digestion in the leech. CONCLUSIONS: The recent investigations on autophagy in invertebrate including planarian, hydra and leech suggest that autophagy is evolutionally conserved from yeast to mammals. The fundamental role of its biological function in the invertebrate contributing to the regeneration and maintenance of cellular homeostasis in these three organisms could make tremendous information to confront life threatening diseases in human including cancers and cardiac disorders.

17.
Mater Sci Eng C Mater Biol Appl ; 114: 111019, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32994025

RESUMO

In biomineralization, organisms have the abilities to produce biominerals with superior properties. One of the most attractive features of biominerals is the presence of the proteins consisting of different contents of amino acids in crystals. In the present work, L-phenylalanine (Phe) was used as an additive for the controllable crystallization of calcium carbonate (CaCO3). The obtained CaCO3 crystals were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), elemental analysis and high-resolution transmission electron microscopy (HRTEM). The experimental results suggest that single calcite crystals are formed at low Phe concentrations. High concentrations of Phe inhibit the nucleation and growth of calcite, and promote the formation of vaterite crystals with solid or hollow structures. The morphology and crystal form of CaCO3 are also significantly affected by the flow rate of CO2. After that, a possible mechanism (competition mechanism) action of Phe in the formation of CaCO3 is proposed. Finally, the effects of temperature on the formation of vaterite were determined to explore the growth mechanism of hexagonal vaterite. The work of controlling the preparation of CaCO3 crystals in the presence of Phe will help us to imitate and learn nature, and bring new insights into understanding bionics. Meanwhile, it provides a new method for the synthesis of CaCO3 biomaterials with different crystal forms and morphologies.


Assuntos
Biomimética , Carbonato de Cálcio , Microscopia Eletrônica de Varredura , Fenilalanina , Difração de Raios X
18.
Elife ; 92020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32538779

RESUMO

The DNA damage response (DDR) is a highly orchestrated process but how double-strand DNA breaks (DSBs) are initially recognized is unclear. Here, we show that polymerized SIRT6 deacetylase recognizes DSBs and potentiates the DDR in human and mouse cells. First, SIRT1 deacetylates SIRT6 at residue K33, which is important for SIRT6 polymerization and mobilization toward DSBs. Then, K33-deacetylated SIRT6 anchors to γH2AX, allowing its retention on and subsequent remodeling of local chromatin. We show that a K33R mutation that mimics hypoacetylated SIRT6 can rescue defective DNA repair as a result of SIRT1 deficiency in cultured cells. These data highlight the synergistic action between SIRTs in the spatiotemporal regulation of the DDR and DNA repair in humans and mice.


Assuntos
Quebras de DNA , Dano ao DNA , Reparo do DNA , Sirtuína 1/fisiologia , Sirtuínas/fisiologia , Acetilação , Animais , Quebras de DNA de Cadeia Dupla , Células HEK293 , Células HeLa , Humanos , Imunoprecipitação , Camundongos , Mutagênese Sítio-Dirigida , Sirtuína 1/metabolismo , Sirtuínas/metabolismo
19.
Biomed Res Int ; 2020: 7164230, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32596359

RESUMO

Planarians are bilaterally symmetric metazoans of the phylum Platyhelminthes. They have well-defined anteroposterior and dorsoventral axes and have a highly structured true brain which consists of all neural cell types and neuropeptides found in a vertebrate. Planarian flatworms are famous for their strong regenerative ability; they can easily regenerate any part of the body including the complete neoformation of a functional brain within a few days and can survive a series of extreme environmental stress. Nowadays, they are an emerging model system in the field of developmental, regenerative, and stem cell biology and have offered lots of helpful information for these realms. In this review, we will summarize the response of planarians to some typical environmental stress and hope to shed light on basic mechanisms of how organisms interact with extreme environmental stress and survive it, such as altered gravity, temperature, and oxygen, and this information will help researchers improve the design in future studies.


Assuntos
Modelos Biológicos , Planárias , Regeneração/fisiologia , Estresse Fisiológico/fisiologia , Animais , Encéfalo/citologia , Encéfalo/fisiologia , Neurônios , Planárias/citologia , Planárias/fisiologia , Células-Tronco
20.
Protein Pept Lett ; 27(11): 1068-1081, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348206

RESUMO

Matrix Metalloproteinases (MMPs) belong to a family of metal-dependent endopeptidases which contain a series of conserved pro-peptide domains and catalytic domains. MMPs have been widely found in plants, animals, and microorganisms. MMPs are involved in regulating numerous physiological processes, pathological processes, and immune responses. In addition, MMPs play a key role in disease occurrence, including tumors, cardiovascular diseases, and other diseases. Compared with invertebrate MMPs, vertebrate MMPs have diverse subtypes and complex functions. Therefore, it is difficult to study the function of MMPs in vertebrates. However, it is relatively easy to study invertebrate MMPs because there are fewer subtypes of MMPs in invertebrates. In the present review, the structure and function of MMPs in invertebrates were summarized, which will provide a theoretical basis for investigating the regulatory mechanism of MMPs in invertebrates.


Assuntos
Matriz Extracelular/enzimologia , Invertebrados/enzimologia , Animais , Matriz Extracelular/genética , Invertebrados/genética , Metaloproteinases da Matriz/classificação , Metaloproteinases da Matriz/genética
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