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1.
Bioresour Technol ; 293: 122135, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31540787

RESUMO

Microalgae have attracted great attention as a promising sustainable resource for biofuel production. In studies aiming to improve lipid accumulation, many key enzymes involved in lipid biosynthesis were identified and confirmed, but genetic engineering remains a challenge in most species of microalgae. In an alternative approach, various chemical modulators can be used to directly regulate the lipid biosynthesis pathway, with similar effects to gene overexpression and interference approaches, including improving the precursor supply and blocking competing pathways. The produced lipid can be protected from being converted into other metabolites by the chemicals such as lipase inhibitors. In addition, a few chemicals were also demonstrated to greatly influence cell growth and lipid accumulation by indirect regulation of the lipid biosynthesis pathway, such as increasing cell permeability or regulating oxidative stress. Thus, adding chemical modulators can be a useful alternative strategy for improving lipid accumulation in large-scale cultivation of microalgae.


Assuntos
Microalgas , Biocombustíveis , Engenharia Genética , Lipídeos
2.
J Virol ; 93(15)2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31118252

RESUMO

Human noroviruses (huNoVs) recognize histo-blood group antigens (HBGAs) as host susceptibility factors. GII.13 and GII.21 huNoVs form a unique genetic lineage that emerged from mainstream GII NoVs via development of a new, nonconventional glycan binding site (GBS) that binds Lea antigen. This previous finding raised the question of whether the new GII.13/21 GBS really has such a narrow glycan binding spectrum. In this study, we provide solid phenotypic and structural evidence indicating that this new GBS recognizes a group of glycans with a common terminal ß-galactose (ß-Gal). First, we found that P domain proteins of GII.13/21 huNoVs circulating at different times bound three glycans sharing a common terminal ß-Gal, including Lec, lactose, and mucin core 2. Second, we solved the crystal structures of the GII.13 P dimers in complex with Lec and mucin core 2, which showed that ß-Gal is the major binding saccharide. Third, nonfat milk and lactose blocked the GII.13/21 P domain-glycan binding, which may explain the low prevalence of GII.13/21 viruses. Our data provide new insight into the host interactions and epidemiology of huNoVs, which would help in the control and prevention of NoV-associated diseases.IMPORTANCE Evidence from both phenotypic binding assay and structural study support the observed interactions of human noroviruses (huNoVs) with histo-blood group antigens (HBGAs) as receptors or attachment factors, affecting their host susceptibility. GII.13 and GII.21 genotypes form a unique genetic lineage that differs from the mainstream GII huNoVs in their unconventional glycan binding site. Unlike the previous findings that GII.13/21 genotypes recognize only Lea antigen, we found in this study that they can interact with a group of glycans with a common terminal ß-Gal, including Lec, lactose, and mucin core 2. However, this wide glycan binding spectrum in a unique binding mode of the GII.13/21 huNoVs appears not to increase their prevalence, probably due to the existence of decoy glycan receptors in human gastrointestinal tract limiting their infection. Our findings shed light on the host interaction and epidemiology of huNoVs, which would impact the strategy of huNoV control and prevention.

3.
Appl Microbiol Biotechnol ; 103(8): 3239-3248, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30877356

RESUMO

Microalgae are arguably the most abundant single-celled eukaryotes and are widely distributed in oceans and freshwater lakes. Moreover, microalgae are widely used in biotechnology to produce bioenergy and high-value products such as polyunsaturated fatty acids (PUFAs), bioactive peptides, proteins, antioxidants and so on. In general, genetic editing techniques were adapted to increase the production of microalgal metabolites. The main genome editing tools available today include zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs), and the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas nuclease system. Due to its high genome editing efficiency, the CRISPR/Cas system is emerging as the most important genome editing method. In this review, we summarized the available literature on the application of CRISPR/Cas in microalgal genetic engineering, including transformation methods, strategies for the expression of Cas9 and sgRNA, the CRISPR/Cas9-mediated gene knock-in/knock-out strategies, and CRISPR interference expression modification strategies.


Assuntos
Sistemas CRISPR-Cas/genética , Edição de Genes , Microalgas/genética , Proteína 9 Associada à CRISPR/genética , Regulação da Expressão Gênica , Marcação de Genes , Engenharia Genética , RNA Guia/genética , Transformação Genética
4.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1864(4): 552-566, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30308323

RESUMO

Microalgal lipids have drawn great attention as a promising sustainable resource for biodiesel or food supplement production. The development of high-performance strains of microalgae by metabolic engineering is invaluable for increasing the quantity or quality of desired lipids. The synthesis routes of lipids used as biodiesel in microalgae are based on fatty acid synthase (FAS) and triacylglycerols (TAG) biosynthesis pathway. Polyunsaturated fatty acids (PUFAs), including ω-6 and ω-3 fatty acids, are essential nutrients for humans. Notably, microalgae possess two distinct pathways for polyunsaturated fatty acids (PUFAs) biosynthesis, including the desaturase/elongase pathway and the polyketide synthase (PKS) pathway. Thus, it is necessary to identify which biosynthetic pathways are responsible for PUFA synthesis in particular microalgae species. In recent years, various key enzymes and functional domains involved in fatty acid and TAG biosynthesis pathway were identified and potentially regulated by genetic engineering approaches to elevate specific lipids content. In addition, other studies have reported the implementation of strategies to increase lipid accumulation based on increasing acetyl-CoA/NADPH supply, enhancing photosynthetic efficiency, or blocking competing pathways. Furthermore, other efforts have used transcription factor engineering to simultaneously regulate multiple genes related to lipid accumulation. This review summarizes recent research about a variety of microalgae lipid biosynthesis pathways, and discusses multiple gene manipulation strategies that have been employed for specific lipid overproduction in industrial microalgae.


Assuntos
Ácidos Graxos Insaturados/biossíntese , Engenharia Metabólica/métodos , Microalgas/crescimento & desenvolvimento , Engenharia Genética , Metabolismo dos Lipídeos , Microalgas/genética , Microalgas/metabolismo , Fotossíntese , Policetídeo Sintases
5.
Biotechnol Biofuels ; 11: 272, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30305845

RESUMO

Microalgae have drawn great attention as promising sustainable source of lipids and carotenoids. Their lipid and carotenoids accumulation machinery can be trigged by the stress conditions such as nutrient limitation or exposure to the damaging physical factors. However, stressful conditions often adversely affect microalgal growth and cause oxidative damage to the cells, which can eventually reduce the yield of the desired products. To overcome these limitations, two-stage cultivation strategies and supplementation of growth-promoting agents have traditionally been utilized, but developing new highly adapted strains is theoretically the simplest strategy. In addition to genetic engineering, adaptive laboratory evolution (ALE) is frequently used to develop beneficial phenotypes in industrial microorganisms during long-term selection under specific stress conditions. In recent years, many studies have gradually introduced ALE as a powerful tool to improve the biological properties of microalgae, especially for improving the production of lipid and carotenoids. In this review, strategies for the manipulation of stress in microalgal lipids and carotenoids production are summarized and discussed. Furthermore, this review summarizes the overall state of ALE technology, including available selection pressures, methods, and their applications in microalgae for the improved production of lipids and carotenoids.

6.
Virol J ; 15(1): 161, 2018 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-30340611

RESUMO

BACKGROUND: Rotaviruses (RVs) are a major cause of acute children gastroenteritis. The rotavirus P [10] belongs to P[I] genogroup of group A rotaviruses that mainly infect animals, while the rotavirus P [10] was mainly identified from human infection. The rotavirus P [10] is an unusual genotype and the recognition pattern of cellular receptors remains unclear. METHODS: We expressed and purified the RV P [10] VP8* protein and investigated the saliva and oligosaccharide binding profiles of the protein. A homology model of the P [10] VP8* core protein was built and the superimposition structural analysis of P [10] VP8* protein on P [19] VP8* in complex with mucin core 2 was performed to explore the possible docking structural basis of P [10] VP8* and mucin cores. RESULTS: Our data showed that rotavirus P [10] VP8* protein bound to all ABO secretor and non-secretor saliva. The rotavirus P [10] could bind strongly to mucin core 2 and weakly to mucin core 4. The homology modeling indicated that RV P [10] VP8* binds to mucin core 2 using a potential glycan binding site that is the same to P [19] VP8* belonging to P[II] genogroup. CONCLUSION: Our results suggested an interaction of rotavirus P [10] VP8* protein with mucin core 2 and mucin core 4. These findings offer potential for elucidating the mechanism of RV A host specificity, evolution and epidemiology.


Assuntos
Polissacarídeos/química , Proteínas de Ligação a RNA/química , Infecções por Rotavirus/virologia , Rotavirus/genética , Proteínas não Estruturais Virais/química , Sítios de Ligação , Escherichia coli/genética , Gastroenterite/virologia , Humanos , Simulação de Acoplamento Molecular , Mucinas/química , Mucinas/metabolismo , Polissacarídeos/metabolismo , Ligação Proteica , Proteínas de Ligação a RNA/metabolismo , Saliva/química , Saliva/virologia , Análise de Sequência de Proteína , Proteínas não Estruturais Virais/metabolismo
7.
AMB Express ; 8(1): 150, 2018 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-30242564

RESUMO

Enhancing lipid productivity and reducing oxidative damage is essential for lipid overproduction in microalgae. In this study, addition of 20 mg/L fulvic acid (FA) resulted a 34.4% increase of lipid yield in Schizochytrium sp. Furthermore, the cooperative effect of FA and EDTA on cell growth and lipid production was investigated. The combined addition of 20 mg/L FA and 1.0 g/L EDTA yielded a maximal cell dry weight of 130.7 g/L and lipid productivity of 1.16 g/L/h, representing 36.4% and threefold increase over the non-supplemented group, respectively. Moreover, compared with the non-supplemented group, the combined addition strategy exhibited overall lower levels of reactive oxygen species and malondialdehyde, which accompanied with 66.7% and 81.9% higher superoxide dismutase and catalase activity, respectively. Furthermore, a 24.1-37.1% increase of malic enzyme and 19.4-25.2% decrease of phosphoenolpyruvate carboxylase activity was observed during the entire fermentation stage (0-108 h). Results suggested that the combined addition strategy not only enhanced lipid accumulation, but also prevented the lipid peroxidation.

8.
Biotechnol Biofuels ; 11: 249, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30245741

RESUMO

Background: Schizochytrium sp. is a promising strain for the production of docosahexaenoic acid (DHA)-rich oil and biodiesel, and has been widely used in the food additive and bioenergy industries. Oxygen is a particularly important environmental factor for cell growth and DHA synthesis. In general, higher oxygen supply favors lipid accumulation, but could lead to a reduction of the DHA percentage in total fatty acids in Schizochytrium sp. To tackle this problem, it is essential to understand the mechanisms regulating the response of Schizochytrium sp. to oxygen. In this study, we aimed to explore the acclimatization of this DHA producer to different oxygen supply conditions by examining the transcriptome changes. Results: Two different fermentation processes, namely normal oxygen supply condition (shift agitation speeds from 400 rpm to 300 rpm) and high oxygen supply condition (constant agitation speeds: 400 rpm), were designed to study how the fermentation characteristics of Schizochytrium sp. HX-308 were affected by different oxygen supply conditions. The results indicated that high oxygen supply condition resulted in 49% and 37.5% improvement in the maximum cell dry weight (CDW) and total lipid concentration, respectively. However, the DHA percentage in total fatty acids decreased to 35%, which was 31.4% lower than that produced by normal oxygen supply condition. Moreover, transcriptome analysis was performed to explore the effect of the oxygen supply condition on genetic expression and metabolism. The results showed that glycolysis and pentose phosphate pathway metabolism-associated genes (hexokinase, phosphofructokinase, fructose-bisphosphate aldolase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) were substantially upregulated in response to high oxygen supply, resulting in more NADPH was available for Schizochytrium. Specially, high oxygen supply condition also led to genes (Δ6 desaturase, Δ12 desaturase, FAS, ORFA, ORFB, and ORFC) involved in fatty acid biosynthesis upregulation. In addition, a transcriptional upregulation of catalase (CAT) became apparent under high oxygen supply condition, while superoxide dismutase (SOD) and ascorbate peroxidase (APX) were found to be down-regulated. Conclusions: This study is the first to investigate the differences of gene expression at different levels of oxygen availability in the DHA producer Schizochytrium. The results of transcriptome analyses indicated that high oxygen supply condition resulting in more NADPH and acetyl-CoA production for cell growth and lipid synthesis in Schizochytrium. Δ12 desaturase and ORFC showed higher expression levels at high oxygen supply condition, which might be the key regulators for enhancing fatty acid biosynthesis in the future. These results enrich the current knowledge regarding genetic expression and provide important information to enhance DHA production in Schizochytrium sp.

9.
Bioresour Technol ; 269: 32-39, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30149252

RESUMO

Docosahexaenoic acid (DHA) has wide-ranging benefits for normal development of the visual and nervous systems in infants. A sustainable source of DHA production through fermentation using Schizochytrium sp. has been developed. In this paper, we present the discovery of growth-uncoupled DHA production by Schizochytrium sp. and the development of corresponding kinetic models of fed-batch fermentations, which can be used to describe and predict the cell growth and substrate utilization as well as lipid and DHA production. Based on this kinetic model, a predictive model of multi-stage continuous fermentation process was established and used to analyze, optimize and design the process parameters. Optimal predicted processes of two-stage and three-stage continuous fermentation were developed and verified in lab-scale bioreactor based on the predicted process parameters. A successful three-stage continuous fermentation was achieved, which increased the lipid, DHA content and DHA productivity by 47.6, 64.3 and 97.1%, respectively, compared with two-stage continuous fermentation.


Assuntos
Ácidos Docosa-Hexaenoicos/metabolismo , Fermentação , Estramenópilas , Reatores Biológicos , Cinética
10.
Bioresour Technol ; 267: 438-444, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30032058

RESUMO

Lipid accumulation of Schizochytrium sp. can be induced by stress condition, but this stress-induction usually reduce cell growth and cause oxidative damage, which can eventually lower the lipid yield. Here, adaptive laboratory evolution (ALE) combined high salinity was performed to enhance the antioxidant system and lipid accumulation. The final strain ALE150, which was obtained after 150 days, showed a maximal cell dry weight (CDW) of 134.5 g/L and lipid yield of 80.14 g/L, representing a 32.7 and 53.31% increase over the starting strain, respectively. Moreover, ALE150 exhibited an overall higher total antioxidant capacity (T-AOC) and lower reactive oxygen species (ROS) levels than the starting strain. Furthermore, the regulatory mechanisms responsible for the improved performance of ALE150 were analyzed by transcriptomic analysis. Genes related to the antioxidant enzymes and central carbon metabolism were up-regulation. Moreover, the metabolic fluxes towards the fatty acid synthase (FAS) and polyketide synthase (PKS) pathways were also changed.


Assuntos
Lipídeos/biossíntese , Microalgas , Salinidade , Oxirredução , Estresse Oxidativo
11.
Biotechnol Biofuels ; 11: 65, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29563968

RESUMO

Background: Schizochytrium sp. is a marine microalga with great potential as a promising sustainable source of lipids rich in docosahexaenoic acid (DHA). This organism's lipid accumulation machinery can be induced by various stress conditions, but this stress induction usually comes at the expense of lower biomass in industrial fermentations. Moreover, oxidative damage induced by various environmental stresses can result in the peroxidation of lipids, and especially polyunsaturated fatty acids, which causes unstable DHA production, but is often ignored in fermentation processes. Therefore, it is urgent to develop new production strains that not only have a high DHA production capacity, but also possess strong antioxidant defenses. Results: Adaptive laboratory evolution (ALE) is an effective method for the development of beneficial phenotypes in industrial microorganisms. Here, a novel cooperative two-factor ALE strategy based on concomitant low temperature and high salinity was applied to improve the production capacity of Schizochytrium sp. Low-temperature conditions were used to improve the DHA content, and high salinity was applied to stimulate lipid accumulation and enhance the antioxidative defense systems of Schizochytrium sp. After 30 adaptation cycles, a maximal cell dry weight of 126.4 g/L and DHA yield of 38.12 g/L were obtained in the endpoint strain ALE-TF30, which was 27.42 and 57.52% higher than parental strain, respectively. Moreover, the fact that ALE-TF30 had the lowest concentrations of reactive oxygen species and malondialdehyde among all strains indicated that lipid peroxidation was greatly suppressed by the evolutionary process. Accordingly, the ALE-TF30 strain exhibited an overall increase of gene expression levels of antioxidant enzymes and polyketide synthases compared to the parental strain. Conclusion: This study provides important clues on how to overcome the negative effects of lipid peroxidation on DHA production in Schizochytrium sp. Taken together, the cooperative two-factor ALE process can not only increase the accumulation of lipids rich in DHA, but also prevent the loss of produced lipid caused by lipid peroxidation. The strategy proposed here may provide a new and alternative direction for the industrial cultivation of oil-producing microalgae.

12.
Bioresour Technol ; 250: 868-876, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29174352

RESUMO

As one of the most important environmental factors, oxygen is particularly important for synthesis of n-3 polyunsaturated fatty acids (n-3 PUFA) in microalgae. In general, a higher oxygen supply is beneficial for cell growth but obstructs PUFA synthesis. The generation of reactive oxygen species (ROS) under aerobic conditions, which leads to the peroxidation of lipids and especially PUFA, is an inevitable aspect of life, but is often ignored in fermentation processes. Irritability, microalgal cells are able to activate a number of anti-oxidative defenses, and the lipid profile of many species is reported to be altered under oxidative stress. In this review, the effects of oxygen on the PUFA synthesis, sources of oxidative damage, and anti-oxidative defense systems of microalgae were summarized and discussed. Moreover, this review summarizes the published reports on microalgal biotechnology involving direct/indirect oxygen regulation and new bioreactor designs that enable the improved production of PUFA.


Assuntos
Ácidos Graxos Insaturados , Microalgas , Oxigênio , Ácidos Graxos , Ácidos Graxos Ômega-3 , Estresse Oxidativo
13.
Biochem Biophys Res Commun ; 490(1): 22-28, 2017 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-28576493

RESUMO

Rhinovirus C (RV-C), a newly identified group of human rhinoviruses (RVs), is associated with exacerbation of severe asthma. The type I interferon (IFN) response induced by this virus and the mechanisms of evasion of IFN-mediated innate immunity for RV-C remain unclear. In this study, we constructed a full-length cDNA clone of RV-C (LZ651) from a clinical sample. IFN-ß mRNA and protein levels were not elevated in differentiated Human bronchial epithelial (HBE) cells at the air-liquid interface infected with RV-C, except in the early stage of infection. The ability to attenuate IFN-ß activation was ascribed to 3Cpro of RV-C, and the 40-His site of 3Cpro played an important role. Furthermore, RIG-I was degraded by 3Cpro in a caspase-dependent manner and 3Cpro cleaved MAVS at 148 Q/A, which inhibited IFN signaling. Taken together, our results demonstrate the mechanism by which RV-C circumvents the production of type I IFN in infected cells.


Assuntos
Tolerância Imunológica , Imunidade Inata/imunologia , Rhinovirus/imunologia , Células HEK293 , Células HeLa , Humanos , Interferon Tipo I/imunologia
14.
Bioresour Technol ; 223: 141-148, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27788427

RESUMO

Oxygen-mediated cell damage is an important issue in aerobic fermentation. In order to counteract these problems, effect of ascorbic acid on cell growth and docosahexaenoic acid (DHA) production was investigated in Schizochytrium sp. Addition of 9g/L ascorbic acid resulted in 16.16% and 30.44% improvement in cell dry weight (CDW) and DHA yield, respectively. Moreover, the total antioxidant capacity (T-AOC) of cells decreased from 2.17 at 12h to 0 at 60h and did not recover, while ascorbic acid addition could extend the time of arrival zero with the reduced intracellular ROS. However, ROS levels still increased after 72h. Therefore, to further solve the problem of high ROS levels and low T-AOC of cells after 72h, a two-point addition strategy was proposed. With this strategy, DHA yield was further increased to 38.26g/L. This work innovatively investigated the feasibility of manipulating Schizochytrium sp. cultivation through ROS level and T-AOC.


Assuntos
Antioxidantes/metabolismo , Ácidos Docosa-Hexaenoicos/biossíntese , Fermentação , Estresse Oxidativo , Estramenópilas/crescimento & desenvolvimento , Biomassa , Oxigênio
15.
J Gen Virol ; 97(10): 2620-2632, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27543110

RESUMO

Human noroviruses are the most important viral pathogens causing epidemic acute gastroenteritis, in which the GII.4 viruses have been predominant worldwide for the past decades. During 2014-2015 winter season, a new GII.17 variant emerged as the predominant virus in China surpassing the GII.4 virus in causing significantly increased acute gastroenteritis outbreaks. Genome sequences of the new GII.17 variant was determined and compared with other GII.17 noroviruses, revealing residue substitutions at specific locations, including the histo-blood group antigen-binding site and the putative antigenic epitopes. Further study of GII.17 outbreaks focusing on host susceptibility showed that the new GII.17 variant infected secretor individuals of A, B, O and Lewis types. Accordingly, the P particles of the new GII.17 variant bound secretor saliva samples of A, B, O and Lewis types with significantly higher binding signals than those of the P particles of the previous GII.17 variants. In addition, human sera collected from the outbreaks exhibited stronger blockade against the binding of the new GII.17 P particles to saliva samples than those against the binding between the P particles of previous GII.17 variants and saliva samples. Taken together, our data strongly suggested that the new GII.17 variant gained new histo-blood group antigen-binding ability and antigenic features, which may contribute to its predominance in causing human norovirus epidemics.


Assuntos
Infecções por Caliciviridae/virologia , Norovirus/isolamento & purificação , Antígenos de Grupos Sanguíneos/genética , Antígenos de Grupos Sanguíneos/metabolismo , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/genética , Infecções por Caliciviridae/metabolismo , China/epidemiologia , Surtos de Doenças , Evolução Molecular , Fezes/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Humanos , Norovirus/classificação , Norovirus/genética , Filogenia
16.
Biomed Environ Sci ; 29(4): 286-9, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-27241739

RESUMO

Norovirus (NoV) is a pathogen that commonly causes viral diarrhea in children. Studies indicate that NoV recognizes human histo-blood group antigens (HBGAs) as cell attachment factors. In order to explore the correlation between of NoV infection and HBGAs, a cross-sectional study was conducted in children less than five years old who were hospitalized with diarrhea in two areas of China between November 2014 and February 2015. Of the paired stool and saliva samples taken from 424 children, NoV was detected in 24 (6%) children, with viral genotypes GII.3 (n=5), GII.4 (n=14), GII.12 (n=1), and GII.17 (n=4). All of the individuals having NoV infection were either secretors (Lea-b+/Lex-y+) or partial secretors (Lea+b+/Lex+y+) except one GII.3 infection of a non-secretor (Lea+b-/Lex+y-). These results suggest that secretor positive is associated with NoV infection, although non-secretors are not absolutely protected from NoV infection.


Assuntos
Antígenos de Grupos Sanguíneos/genética , Infecções por Caliciviridae/sangue , Infecções por Caliciviridae/complicações , Diarreia/sangue , Diarreia/etiologia , Gastroenterite/sangue , Norovirus/fisiologia , Infecções por Caliciviridae/virologia , Pré-Escolar , China , Estudos Transversais , Diarreia/virologia , Fezes/virologia , Gastroenterite/virologia , Genótipo , Humanos , Lactente
17.
Virology ; 494: 108-18, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27107253

RESUMO

A recent histopathologic study implicated human tonsillar crypt epithelium as an important site for EV71 replication in EV71-caused fatal cases. This study aimed to confirm the susceptibility of human tonsillar epithelium to EV71. Two human tonsillar epithelial cell lines (UT-SCC-60A and UT-SCC-60B) were susceptive to EV71, and PI3K/AKT, p38, ERK1/2, and JNK1/2 signal pathways were activated. Interferon-α, IL-8, IL-1ß, IL-6 and IL-12p40 were induced and regulated by PI3K/AKT, p38, ERK1/2, and JNK1/2 signal pathways. PI3K/AKT pathway activation appeared to suppress the induction of TNF-α, which induced cell survival by inhibiting GSK-3ß. The activation of NF-κB was observed but inhibited by these pathways in EV71 infection. Furthermore, ERK1/2 and JNK1/2 were essential for efficient EV71 replication. Human tonsillar epithelial cells support EV71 replication and display innate antiviral immunity in vitro, indicating that human tonsillar epithelial cells may be novel targets for EV71 infection and replication in vivo.


Assuntos
Citocinas/biossíntese , Enterovirus Humano A/fisiologia , Infecções por Enterovirus/metabolismo , Infecções por Enterovirus/virologia , Células Epiteliais/metabolismo , Células Epiteliais/virologia , Tonsila Palatina/metabolismo , Tonsila Palatina/virologia , Animais , Biomarcadores , Linhagem Celular , Citocinas/genética , Efeito Citopatogênico Viral , Suscetibilidade a Doenças , Células Epiteliais/patologia , Interações Hospedeiro-Patógeno , Humanos , Mediadores da Inflamação/metabolismo , Queratinas/metabolismo , Glicoproteínas de Membrana Associadas ao Lisossomo/metabolismo , Glicoproteínas de Membrana/metabolismo , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Viral , Receptores Depuradores/metabolismo , Transdução de Sinais , Proteínas Virais/genética , Proteínas Virais/metabolismo , Replicação Viral
18.
Bioresour Technol ; 211: 374-81, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27030957

RESUMO

Adaptive laboratory evolution (ALE) is an effective method in changing the strain characteristics. Here, ALE with high oxygen as a selection pressure was applied to improve the production capacity of Schizochytrium sp. Results showed that cell dry weight (CDW) of endpoint strain was 32.4% higher than that of starting strain. But slight lipid accumulation impairment was observed. These major performance changes were accompanied with enhanced isocitrate dehydrogenase enzyme activity and reduced ATP:citrate lyase enzyme activity. And a serious decrease of 62.6% in SDHA 140rpm→170rpm was observed in the endpoint strain. To further study the docosahexaenoic acid (DHA) production ability of evolved strain, fed-batch strategy was applied and 84.34g/L of cell dry weight and 26.40g/L of DHA yield were observed. In addition, endpoint strain produced greatly less squalene than starting strain. This work demonstrated that ALE may be a promising tool in modifying microalga strains.


Assuntos
Ácidos Docosa-Hexaenoicos/biossíntese , Microalgas/efeitos dos fármacos , Oxigênio/farmacologia , Estramenópilas/efeitos dos fármacos , Fermentação , Microalgas/metabolismo , Microalgas/fisiologia , Estramenópilas/metabolismo , Estramenópilas/fisiologia
19.
Sci Rep ; 6: 22361, 2016 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-26924426

RESUMO

Hepatitis A virus (HAV) is a hepatotropic picornavirus that causes acute liver disease worldwide. Here, we report on the identification of a novel hepatovirus tentatively named Marmota Himalayana hepatovirus (MHHAV) in wild woodchucks (Marmota Himalayana) in China. The genomic and molecular characterization of MHHAV indicated that it is most closely related genetically to HAV. MHHAV has wide tissue distribution but shows tropism for the liver. The virus is morphologically and structurally similar to HAV. The pattern of its codon usage bias is also consistent with that of HAV. Phylogenetic analysis indicated that MHHAV groups with known HAVs but forms an independent branch, and represents a new species in the genus Hepatovirus within the family Picornaviridae. Antigenic site analysis suggested MHHAV has a new antigenic property to other HAVs. Further evolutionary analysis of MHHAV and primate HAVs led to a most recent common ancestor estimate of 1,000 years ago, while the common ancestor of all HAV-related viruses including phopivirus can be traced back to 1800 years ago. The discovery of MHHAV may provide new insights into the origin and evolution of HAV and a model system with which to explore the pathogenesis of HAV infection.


Assuntos
Hepatovirus/classificação , Marmota/virologia , Animais , Antígenos Virais , Composição de Bases , Teorema de Bayes , Códon , Epitopos/imunologia , Evolução Molecular , Genoma Viral , Genômica , Genótipo , Hepatovirus/genética , Hepatovirus/imunologia , Hepatovirus/ultraestrutura , Conformação de Ácido Nucleico , Fases de Leitura Aberta , Filogenia , RNA Viral
20.
PLoS One ; 10(8): e0134584, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26274396

RESUMO

Rotaviruses (RVs) are an important cause of severe gastroenteritis in children. It has been found that RV may recognize the histo-blood group antigens (HBGAs) as ligands or receptors and bind HBGAs in a type-dependent manner. In this study, we investigated the binding specificity of VP8* proteins from human rotaviruses (RV) that are prevalent in China including genotypes P[4], P[6], and P[8]. Through the saliva- and oligosaccharide-based binding assays, we found that the VP8* proteins of P[4] and P[8] RV showed similar reactivity with the Leb and H type 1 antigens, while P[6] RV weakly bound the Leb antigen. These findings may facilitate further research into RV host specificity and vaccine development.


Assuntos
Antígenos Virais/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo , Rotavirus/genética , Rotavirus/metabolismo , Adulto , Animais , Antígenos Virais/genética , Antígenos de Grupos Sanguíneos/genética , Criança , Feminino , Gastroenterite/sangue , Gastroenterite/virologia , Genótipo , Humanos , Dados de Sequência Molecular , Ligação Proteica , Proteínas de Ligação a RNA/metabolismo , Coelhos , Rotavirus/imunologia , Infecções por Rotavirus/sangue , Saliva/metabolismo , Saliva/virologia , Proteínas não Estruturais Virais/metabolismo
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