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2.
Sensors (Basel) ; 22(20)2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36298281

RESUMO

Energy limitation is one of the intrinsic shortcomings of wireless sensor networks (WSNs), although it has been widely applied in disaster response, battlefield surveillance, wildfire monitoring, radioactivity detection, etc. Due to the large amount of energy consumed for data transmission, how to prolong the network lifespan by designing various hierarchical routing protocols has attracted more and more attention. As a result, numerous achievements have emerged successively. However, these presented mechanisms can rarely guarantee the satisfactory quality of service (QoS), while lowering the energy cost level of WSNs. Meanwhile, invulnerability is undoubtedly an excellent quantitative index to assess QoS. Therefore, it is critical to develop a practical routing method to optimize network lifetime by considering both invulnerability and energy efficiency. Game theory is suitable for such a critical problem as it can be used in node or at network level to encourage the decision-making capabilities of WSNs. In this paper, a novel invulnerability-aware clustering routing algorithm (IACRA) using game-theoretic method is proposed to solve the predicament. The core features of the addressed game-theory-based routing protocol include integral invulnerability awareness, optimal cluster head selection in hierarchical routing, distance-aware cluster head discovery, and cluster rotation update mechanism for lifetime optimization. Particularly, the integral network invulnerability based on weighted fusion is constructed for further defining the profit model by combining the invulnerability indicators used to evaluate the local and whole network. Meanwhile, the optimal probability function of every node elected as CH in per cluster is established through the game between invulnerability and node energy consumption. In addition, the cluster update mechanism base on cluster rotation is proposed to avoid the rapid death of nodes with large energy consumption for maximizing network lifetime. The experimental results indicated a significant improvement in energy balance as well as in invulnerability compared with the other three kinds of well-known clustering routing protocols including GEEC (Game-theory-based energy efficient clustering routing protocol), HGTD (Hybrid, game-theory-based distributed clustering protocol), and EEGC (Efficient energy-aware and game-theory-based clustering protocol). Concretely, at the 400 communication rounds, the invulnerability of IACRA was higher than that of GEEC, HGTD, and EEGC by 77.56%, 29.45% and 15.90%, respectively, and the average residual energy of IACRA was 8.61%, 18.35% and 6.36% larger than that of GEEC, HGTD, and EEGC, respectively. Based on these results, the proposed protocol can be utilized to increase the capability of WSNs against deterioration of QoS and energy constraints.


Assuntos
Redes de Comunicação de Computadores , Tecnologia sem Fio , Análise por Conglomerados , Algoritmos , Teoria dos Jogos
3.
RNA Biol ; 18(8): 1085-1098, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-32991234

RESUMO

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas (CRISPR-associated proteins) system represents, in prokaryotes, an adaptive and inheritable immune response against invading DNA. The discovery of anti-CRISPR proteins (Acrs), which are inhibitors of CRISPR-Cas, mainly encoded by phages and prophages, showed a co-evolution history between prokaryotes and phages. In the past decade, the CRISPR-Cas systems together with the corresponding Acrs have been turned into a genetic-engineering tool. Among the six types of CRISPR-Cas characterized so far, type II CRISPR-Cas system is the most popular in biotechnology. Here, we discuss about the discovery, the reported inhibitory mechanisms, and the applications in both gene editing and gene transcriptional regulation of type II Acrs. Moreover, we provide insights into future potential research and feasible applications.


Assuntos
Archaea/genética , Bactérias/genética , Bacteriófagos/genética , Sistemas CRISPR-Cas , Edição de Genes/métodos , Prófagos/genética , Archaea/imunologia , Archaea/virologia , Bactérias/imunologia , Bactérias/virologia , Bacteriófagos/metabolismo , Coevolução Biológica , Biotecnologia/instrumentação , Biotecnologia/tendências , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Humanos , Prófagos/metabolismo , RNA Guia de Cinetoplastídeos/genética , RNA Guia de Cinetoplastídeos/metabolismo , Biologia Sintética/instrumentação , Biologia Sintética/tendências
4.
Phys Chem Chem Phys ; 23(34): 18744-18751, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34612412

RESUMO

The rapid development of electronic devices requires high power storage batteries. However, reported 3D carbon-based materials are semiconductors or metals and are used in Li- or Na-ion batteries with low capacities. Thus, it is of interest to discover whether there is a universal semi-metallic material for use in high performance Li-, Na-, and K-ion batteries. Inspired by the recent synthesis of 3D carbon-based materials, in the research reported here, a 3D regular porous structure (bct-C56) is designed using graphene sheets. The porous carbon-based material has mechanical, dynamic, thermal, and mechanical stabilities. Interestingly, bct-C56 exhibits semi-metallic features with two Dirac nodal surfaces with mirror symmetry, as well as high Fermi velocities, indicating high electron-transport abilities. More excitingly, its theoretical capacities are 743.8, 478.2, and 425.0 mA h g-1, with diffusion barriers of 0.05-0.12, 0.07-0.12, and 0.03-0.05 eV, average OCVs of 0.31, 0.45, and 0.59 V, and volume expansion levels of 1.2%, 0.02%, and 3.1%, in Li-, Na-, and K-ion batteries, respectively. All these excellent characteristics suggest that semi-metallic bct-C56 is a universal anode material for use in metal-ion batteries with a fast charge-discharge rate. In this research, not only was a new material with a Dirac nodal surface feature designed, but it also offers an approach for the creation of high performance and universal metal-ion battery anodes with 3D porous carbon materials.

5.
Angew Chem Int Ed Engl ; 60(20): 11288-11293, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-33709627

RESUMO

Traditional macrocyclic hosts have finite cavity sizes, generally 5-10 Å, which are commonly adaptive to recognize small guests rather than biological macromolecules. Here two water-soluble large-sized quaterphen[n]arenes (WQPns, n=3, 4) were designed and synthesized. These two hosts present significantly distinct recognition abilities. Specifically, they could strongly complex an antimicrobial peptide, pexiganan (PXG) with the association constants (Ka ) of (4.20±0.23)×104  M-1 for PXG/WQP3 and (2.46±0.44)×105  M-1 for PXG/WQP4. Complexation of PXG by WQP3 and WQP4 served to decrease the hemolysis of PXG in rabbit red blood cells in a statistically significant way. Furthermore, host-guest complexation was shown to substantially enhance metabolic stability of PXG in presence of proteinase K, rat plasma and liver or kidney homogenates.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Calixarenos/química , Compostos Macrocíclicos/química , Calixarenos/síntese química , Compostos Macrocíclicos/síntese química , Estrutura Molecular , Estabilidade Proteica
6.
J Nanobiotechnology ; 18(1): 98, 2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32680576

RESUMO

BACKGROUND: In this study, we aimed to design a novel oral insulin delivery system, named "oil-soluble" reversed lipid nanoparticles (ORLN), in which a hydrophilic insulin molecule is encapsulated by a phospholipid (PC) shell and dissolved in oil to prevent the enzymatic degradation of insulin. ORLN was characterized by transmission electron microscopy and dynamic light scattering. RESULTS: In vitro enzymatic stability studies showed higher concentrations of insulin in cells incubated with ORLN-encapsulated insulin than in those incubated with free insulin solution in artificial intestinal fluid (pH 6.5). The protective effect of ORLN was attributed to its special release behavior and the formulation of the PC shell and oil barrier. Furthermore, an in vivo oral efficacy study confirmed that blood glucose levels were markedly decreased after ORLN administration in both healthy and diabetic mice. In vivo pharmacokinetic results showed that the bioavailability of ORLN-conjugated insulin was approximately 28.7% relative to that of the group subcutaneously administered with an aqueous solution of insulin, indicating enhanced oral absorption. CONCLUSIONS: In summary, the ORLN system developed here shows promise as a nanocarrier for improving the oral absorption of insulin.


Assuntos
Portadores de Fármacos , Insulina , Nanopartículas , Fosfolipídeos/química , Administração Oral , Animais , Disponibilidade Biológica , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/farmacologia , Insulina/administração & dosagem , Insulina/química , Insulina/farmacocinética , Insulina/farmacologia , Masculino , Camundongos , Nanopartículas/administração & dosagem , Nanopartículas/química , Ratos Wistar , Solubilidade
7.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 36(1): 50-58, 2019 Feb 25.
Artigo em Zh | MEDLINE | ID: mdl-30887776

RESUMO

The precise recognition of feature points of impedance cardiogram (ICG) is the precondition of calculating hemodynamic parameters based on thoracic bioimpedance. To improve the accuracy of detecting feature points of ICG signals, a new method was proposed to de-noise ICG signal based on the adaptive ensemble empirical mode decomposition and wavelet threshold firstly, and then on the basis of adaptive ensemble empirical mode decomposition, we combined difference and adaptive segmentation to detect the feature points, A, B, C and X, in ICG signal. We selected randomly 30 ICG signals in different forms from diverse cardiac patients to examine the accuracy of the proposed approach and the accuracy rate of the proposed algorithm is 99.72%. The improved accuracy rate of feature detection can help to get more accurate cardiac hemodynamic parameters on the basis of thoracic bioimpedance.

8.
Biol Pharm Bull ; 40(2): 135-144, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28154251

RESUMO

Hydroxysafflor yellow A (HSYA) is an effective ingredient of the Chinese herb Carthamus tinctorius L. The present study investigated the protective effect of HSYA on lipopolysaccharide (LPS)-induced acute respiratory distress syndrome in mice, and the underlying mechanisms involved. HSYA (14, 28, 56 mg/kg) was intraperitoneally injected to mice once daily from day 1 to 10 after LPS administration. HSYA attenuated the body weight loss, the augmented left index and the increase of pathologic changes in pulmonary inflammation caused by LPS. Treatment with HSYA also alleviated increased expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, transforming growth factor (TGF)-ß1, collagen (Col) I, Col III, α-smooth muscle actin (α-SMA), myeloid differentiation (MD)-2, Toll-like receptor 4 (TLR4) and cluster differentiation (CD)14 at the mRNA (RT-PCR) and protein levels (Western blot and enzyme-linked immuno sorbent assay). Moreover, HSYA inhibited the elevated levels of nuclear factor (NF)-κB and α-SMA in lung tissue (immunohistochemistry), and alleviated the slight collagen deposition in pulmonary tissues (Masson's trichrome staining). HSYA inhibited the specific binding of fluorescein isothiocyanate (FITC)-LPS on human lung epithelial cell line (A549) or human umbilical vein cell line (Eahy926) cells (flow cytometry). These findings suggested that HSYA has a protective effect on acute respiratory distress syndrome (ARDS) induced by LPS through blocking the TLR4/NF-κB pathway, and that the TLR4 receptor might be a target of HSYA on the cell membrane.


Assuntos
Carthamus tinctorius , Chalcona/análogos & derivados , Lipopolissacarídeos/toxicidade , Extratos Vegetais/uso terapêutico , Quinonas/uso terapêutico , Síndrome do Desconforto Respiratório/induzido quimicamente , Síndrome do Desconforto Respiratório/tratamento farmacológico , Células A549 , Animais , Chalcona/isolamento & purificação , Chalcona/uso terapêutico , Relação Dose-Resposta a Droga , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Extratos Vegetais/isolamento & purificação , Quinonas/isolamento & purificação , Síndrome do Desconforto Respiratório/patologia
9.
Biol Pharm Bull ; 37(10): 1591-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25056232

RESUMO

Our previous studies found that hydroxysafflor yellow A (HSYA), an active ingredient in Carthamus tinctorius L., has anti-inflammatory and anti-fibrosis properties. In this study, we investigated the effect of HSYA on small airway remodeling (SAR) in a chronic obstructive pulmonary disease (COPD) rat model induced by cigarette smoke and lipopolysaccharide (LPS). SAR is a common lesion in COPD characterized by thickening of the airway wall, mainly by subepithelial fibrosis. In this study the thickness of the small airway was determined by total wall area/basement membrane perimeter (WAt/Pbm). Collagen deposition of the small airway was assessed by Masson's trichrome staining. HSYA significantly attenuated the thickening and collagen deposition of the small airway and inhibited transforming growth factor ß1 (TGF-ß1) mRNA and protein expression in COPD rat. In addition, HSYA inhibited the phosphorylation of p38 mitogen-activated protein kinases (MAPK) in the lung tissue of rat. HSYA can attenuate experimentally induced airway remodeling and this attenuation may be attributed to suppression of TGF-ß1 expression.


Assuntos
Remodelação das Vias Aéreas/efeitos dos fármacos , Chalcona/análogos & derivados , Modelos Animais de Doenças , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Quinonas/farmacologia , Quinonas/uso terapêutico , Remodelação das Vias Aéreas/fisiologia , Animais , Chalcona/farmacologia , Chalcona/uso terapêutico , Masculino , Doença Pulmonar Obstrutiva Crônica/patologia , Ratos , Ratos Wistar
10.
Int J Biol Macromol ; : 134309, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39089544

RESUMO

Plant-derived exosome-like nanovesicles (ELNs) are nano-sized vesicles extracted from edible plants. Lycium ruthenicum Murray (LRM) has been gaining increasing attention due to its nutritional and medicinal value, but the ELNs in LRM has not been reported. In this study, LRM-ELNs were obtained, and the proteins, lipids, microRNAs (miRNAs) and active components in LRM tissues and LRM-ELNs was analyzed by LC-MS/MS, LC-MS, high-throughput sequencing techniques, and physical and chemical analysis. LRM-ELNs can be uptaken by PC12 cells through macropinocytosis and caveolin-mediated endocytosis primarily. Transcriptomic and western blot experiments indicate that LRM-ELNs can inhibit Aß-induced apoptosis in PC12 cells through the MAPK and PI3K/AKT signaling pathways, with miRNAs playing a crucial role. These results indicated that LRM-ELNs have the protection effect on PC12 cells and can be considered as dietary supplements for alleviating neurodegenerative diseases.

11.
Virology ; 594: 110050, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38479071

RESUMO

The SARS-CoV-2 Omicron variant, which was classified as a variant of concern (VOC) by the World Health Organization on 26 November 2021, has attracted worldwide attention for its high transmissibility and immune evasion ability. The existing COVID-19 vaccine has been shown to be less effective in preventing Omicron variant infection and symptomatic infection, which brings new challenges to vaccine development and application. Here, we evaluated the immunogenicity and safety of an Omicron variant COVID-19 inactivated vaccine containing aluminum and CpG adjuvants in a variety of animal models. The results showed that the vaccine candidate could induce high levels of neutralizing antibodies against the Omicron variant virus and binding antibodies, and significantly promoted cellular immune response. Meanwhile, the vaccine candidate was safe. Therefore, it provided more foundation for the development of aluminum and CpG as a combination adjuvant in human vaccines.


Assuntos
Compostos de Alúmen , Vacinas contra COVID-19 , COVID-19 , Animais , Humanos , Alumínio , SARS-CoV-2 , COVID-19/prevenção & controle , Adjuvantes Imunológicos , Imunidade Celular , Anticorpos Neutralizantes , Vacinas de Produtos Inativados , Anticorpos Antivirais
12.
Methods Mol Biol ; 2598: 29-44, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36355283

RESUMO

Experimental data suggests that tissue-specific progenitors are present within hyaline articular cartilage with the potential to contribute to growth, maintenance, and repair. In this chapter, we show how colony-forming progenitor-like cells can be isolated from bovine articular cartilage using differential adhesion to fibronectin. Furthermore, we describe the optimal conditions and factors required to differentiate these progenitor cells to produce hyaline articular cartilage.


Assuntos
Cartilagem Articular , Bovinos , Animais , Condrogênese , Condrócitos , Diferenciação Celular , Células-Tronco , Células Cultivadas
13.
PLoS One ; 18(11): e0294761, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37992123

RESUMO

Reconstruction of the outer ear currently requires harvesting of cartilage from the posterior of the auricle or ribs leading to pain and donor site morbidity. An alternative source for auricular reconstruction is in vitro tissue engineered cartilage using stem/progenitor cells. Several candidate cell-types have been studied with tissue-specific auricular cartilage progenitor cells (AuCPC) of particular interest. Whilst chondrogenic differentiation of competent stem cells using growth factor TGFß1 produces cartilage this tissue is frequently fibrocartilaginous and lacks the morphological features of hyaline cartilage. Recent work has shown that growth factor BMP9 is a potent chondrogenic and morphogenetic factor for articular cartilage progenitor cells, and we hypothesised that this property extends to cartilage-derived progenitors from other tissues. In this study we show monoclonal populations of AuCPCs from immature and mature bovine cartilage cultured with BMP9 produced cartilage pellets have 3-5-fold greater surface area in sections than those grown with TGFß1. Increased volumetric growth using BMP9 was due to greater sGAG deposition in immature pellets and significantly greater collagen accumulation in both immature and mature progenitor pellets. Polarised light microscopy and immunohistochemical analyses revealed that the organisation of collagen fibrils within pellets is an important factor in the growth of pellets. Additionally, chondrocytes in BMP9 stimulated cell pellets had larger lacunae and were more evenly dispersed throughout the extracellular matrix. Interestingly, BMP9 tended to normalise the response of immature AuCPC monoclonal cell lines to differentiation cues whereas cells exhibited more variation under TGFß1. In conclusion, BMP9 appears to be a potent inducer of chondrogenesis and volumetric growth for AuCPCs a property that can be exploited for tissue engineering strategies for reconstructive surgery though with the caveat of negligible elastin production following 21-day treatment with either growth factor.


Assuntos
Cartilagem Articular , Cartilagem da Orelha , Animais , Bovinos , Colágeno Tipo II/metabolismo , Condrogênese/fisiologia , Condrócitos/metabolismo , Diferenciação Celular/fisiologia , Cartilagem Articular/metabolismo , Colágeno/metabolismo , Células Cultivadas
14.
Drug Deliv ; 30(1): 20-27, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36452996

RESUMO

Organophosphorus agents, also known as nerve agents, are very dangerous chemicals that were used as chemical warfare agents. HI-6 is one of the most promising reactivators which is effective in reactivating AChE inhibited by many nerve agents. However, the fast in-vivo clearance of HI-6 became a large barrier for first aid use under some sophisticated circumstances. In this study, PEGylated liposomes loading HI-6 were prepared and evaluated in vitro and in vivo. For PEG-LP-HI-6, the optimal formulation's loading efficiency and encapsulation efficiency were 6.47 ± 0.10% and 71.2 ± 1.15%, respectively. According to the pharmacokinetic results, compared with free HI-6 and LP-HI-6, the intravenous injection of PEG-LP-HI-6 significantly extended t1/2 (1.47 ± 0.29 h), MRT (1.44 ± 0.07 h), and improved the AUC of HI-6 in vivo. Drug concentrations in the CNS also increased after the intravenous administration of PEG-LP-HI-6. For in vivo treatment study, twenty minutes after poison exposure, the survival rate of animals in saline, free HI-6, LP-HI-6 and PEG-LP-HI-6 groups were 0, 0, 30% and 70%, respectively. Compared with the non-PEGylated liposomes group and free HI-6, PEG-LP-HI-6 could prolong the survival time of experimental animals and alleviate the neurotoxic symptoms, which demonstrated great potential as a first-aid strategy for acute organophosphorus agent poisoning.


Assuntos
Agentes Neurotóxicos , Intoxicação por Organofosfatos , Animais , Lipossomos , Primeiros Socorros , Intoxicação por Organofosfatos/tratamento farmacológico
15.
Heliyon ; 9(6): e16518, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37292326

RESUMO

Iridoid is a special class of monoterpenoids, whose basic skeleton is the acetal derivative of antinodilaldehyde with a bicyclic H-5/H-9ß, ß-cisfused cyclopentan pyran ring. They were often existed in Valerianaceae, Rubiaceae, Scrophulariaceae and Labiaceae family, and has various biological activities, such as anti-inflammatory, hypoglycemic, neuroprotection, and soon. In this review, iridoids from Patrinia (Valerianaceae family), and the active ones as well as their mechanisms in recent 20 years were summarized. Up to now, a total of 115 iridoids had been identified in Patrinia, among which 48 had extensive biological activities mainly presented in anti-inflammatory, anti-tumor and neuroprotective. And the mechanisms involved in MAPK, NF-κB and JNK signal pathways. The summary for iridoids and their activities will provide the evidence to exploit the iridoids in Patrinia.

16.
Vaccines (Basel) ; 11(12)2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38140149

RESUMO

There are some concerns about the safety of live attenuated yellow fever vaccines (YF-live), particularly viscerotropic adverse events, which have a high mortality rate. The cellular production of the vaccine will not cause these adverse effects and has the potential to extend applicability to those who have allergic reactions, immunosuppression, and age. In this study, inactivated yellow fever (YF) was prepared and adsorbed with Alum/CpG. The cellular and humoral immunities were investigated in a mouse model. The results showed that Alum/CpG (20 µg/mL) could significantly increase the binding and neutralizing activities of the antibodies against YF. Moreover, the antibody level at day 28 after one dose was similar to that of the attenuated vaccine, but significantly higher after two doses. At the same time, Alum/CpG significantly increased the levels of IFN-γ and IL-4 cytokines.

17.
ACS Synth Biol ; 11(1): 176-190, 2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-34994540

RESUMO

Type II CRISPR-(d)SpCas9 and anti-CRISPR proteins (AcrIIs) show evidence of coevolution and competition for survival between bacteria and phages. In biotechnology, CRISPR-(d)SpCas9 is utilized for gene editing and transcriptional regulation. Moreover, its activity is controlled by AcrIIs. However, studies of dSpCas9/AcrII-based transcription regulation in Saccharomyces cerevisiae are rare. In this work, we used dSpCas9 as a template to engineer new transcription activators. We found that the most performant activation system requires the use of bare dSpCas9 in conjunction with scaffold gRNA (scRNA). This means that activation domains shall not be fused to dSpCas9 but rather interact with scRNA. We showed that a low amount of sgRNA is not a limiting factor in dSpCas9-driven transcription regulation. Moreover, a high quantity of sgRNA does not improve, generally, activation (and repression) efficiency. Importantly, we analyzed the performance of AcrIIA2, AcrIIA4, and AcrIIA5 in S. cerevisiae in depth. AcrIIA4 is the strongest of the three AcrIIs and also the only one able to induce high inhibition at low concentrations. However, the activation domains fused to dSpCas9 hindered interactions with the AcrIIs as well and limited their control of gene transcription regulation, confirming that bare dSpCas9 is the best solution for building synthetic genetic networks in yeast.


Assuntos
RNA Guia de Cinetoplastídeos , Saccharomyces cerevisiae , Sistemas CRISPR-Cas/genética , Edição de Genes , Expressão Gênica , RNA Guia de Cinetoplastídeos/genética , RNA Guia de Cinetoplastídeos/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
18.
Front Bioeng Biotechnol ; 10: 922949, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35721864

RESUMO

CRISPR-Cas systems provide powerful biological tools for genetic manipulation and gene expression regulation. Class 2 systems, comprising type II, type V, and type VI, have the significant advantage to require a single effector Cas protein (Cas9, Cas12, and Cas13 respectively) to cleave nucleic acids upon binding the crRNA. Both Cas9 and Cas12 recognize DNA and induce a double-strand break in it. In contrast, Cas13 bind and cleave RNA exclusively. However, some Cas9 homologs have shown RNase activity as well. Here, we harnessed Nme1Cas9, LwaCas13a, and RfxCas13d to carry out gene downregulation in Saccharomyces cerevisiae by triggering mRNA degradation. To avoid potential DNA damage, we mutated Nme1Cas9 into d16ANme1Cas9 that lost the nuclease activity of the RuvC domain but retained the active HNH domain, able to act on the target DNA strand and, therefore, on the corresponding transcript. Our results showed that d16ANme1Cas9 is a functional RNase in vivo, although with moderate activity since it provoked a fluorescence reduction from 21% to 32%. Interestingly, d16ANme1Cas9 works in a PAM-independent way nor demands helper PAMmer molecules. LwaCas13a and RfxCas13d appeared substantially unfunctional in S. cerevisiae, though they were shown to perform well in mammalian cells. To the best of our knowledge, this is the first report about the working in vivo of a variant of Nme1Cas9 as an RNase and the issues connected with the usage of Cas13 proteins in S. cerevisiae.

19.
J Vis Exp ; (188)2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36342156

RESUMO

Synthetic gene Boolean gates and digital circuits have a broad range of applications, from medical diagnostics to environmental care. The discovery of the CRISPR-Cas systems and their natural inhibitors-the anti-CRISPR proteins (Acrs)-provides a new tool to design and implement in vivo gene digital circuits. Here, we describe a protocol that follows the idea of the "Design-Build-Test-Learn" biological engineering cycle and makes use of dCas9/dCas12a together with their corresponding Acrs to establish small transcriptional networks, some of which behave like Boolean gates, in Saccharomyces cerevisiae. These results point out the properties of dCas9/dCas12a as transcription factors. In particular, to achieve maximal activation of gene expression, dSpCas9 needs to interact with an engineered scaffold RNA that collects multiple copies of the VP64 activation domain (AD). In contrast, dCas12a shall be fused, at the C terminus, with the strong VP64-p65-Rta (VPR) AD. Furthermore, the activity of both Cas proteins is not enhanced by increasing the amount of sgRNA/crRNA in the cell. This article also explains how to build Boolean gates based on the CRISPR-dCas-Acr interaction. The AcrIIA4 fused hormone-binding domain of the human estrogen receptor is the core of a NOT gate responsive to ß-estradiol, whereas AcrVAs synthesized by the inducible GAL1 promoter permits to mimic both YES and NOT gates with galactose as an input. In the latter circuits, AcrVA5, together with dLbCas12a, showed the best logic behavior.


Assuntos
Sistemas CRISPR-Cas , Redes Reguladoras de Genes , Humanos , Regiões Promotoras Genéticas , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Pequeno RNA não Traduzido/genética , RNA Guia de Sistemas CRISPR-Cas
20.
Sci Rep ; 12(1): 20161, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36424406

RESUMO

Bioreactors are one of the most important, basic pieces of equipment in the biopharmaceutical industry. Understanding the effects of mechanical damage and other factors on the physiological state of cells during cell matrix culture is the basis for continuously achieving greater efficiency and higher product quality. In this study, Vero cells were used as a model and apoptosis, senescence, transcriptomics, proteomics, and metabolomics were carried out for analysis at the cellular and molecular levels. The results showed that compared with cells cultured in the simulated natural state, the cells cultured in the basket bioreactor displayed no obvious senescence. Additionally, the proportion of early apoptotic cells increased, but the proportions of damaged, late apoptotic and dead cells did not change significantly. The transcription levels of aminoacyl-tRNA synthetase and cyclin D1 and the expression levels of DNA replication licensing factor, methenyltetrahydrofolate cyclohydrolase, arachidonic acid and other metabolites of cells cultured in the basket bioreactor were significantly increased. These results suggest that DNA replication, protein translation and the metabolic activities in cells cultured in basket bioreactors are more active, which is more conducive to cell amplification and target product production. In this study, the growth and physiological state of cells in a basket bioreactor were characterized at the molecular level for the first time. Additionally, a tool to evaluate the physiological state of cells in a bioreactor was established, which can be used to guide the development and optimization of cell matrix culture conditions in industrial production and improve the production efficiency of the target products.


Assuntos
Reatores Biológicos , Técnicas de Cultura de Células , Animais , Chlorocebus aethiops , Células Vero , Técnicas de Cultura de Células/métodos , Metabolômica , Indústrias
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