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1.
Mol Biol Evol ; 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31163451

RESUMO

Persian walnut (Juglans regia) is cultivated worldwide for its high-quality wood and nuts, but its origin has remained mysterious because in phylogenies it occupies an unresolved position between American black walnuts and Asian butternuts. Equally unclear is the origin of the only American butternut, J. cinerea. We re-sequenced the whole genome of 80 individuals from 19 of the 22 species of Juglans and assembled the genome of its relatives Pterocarya stenoptera and Platycarya strobilacea. Using phylogenetic-network analysis of single-copy nuclear genes, genome-wide site pattern probabilities, and Approximate Bayesian Computation (ABC) we discovered that J. regia (and its landrace J. sigillata) arose as a hybrid between the American and the Asian lineages and that J. cinerea resulted from massive introgression from an immigrating Asian butternut into the genome of an American black walnut. ABC modelling placed the hybrid origin in the late Pliocene, ∼3.45 Ma, with both parental lineages since having gone extinct in Europe.

2.
Bioinformatics ; 35(20): 4129-4139, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30887023

RESUMO

MOTIVATION: With the abundant medical resources, especially literature available online, it is possible for people to understand their own health status and relevant problems autonomously. However, how to obtain the most appropriate answer from the increasingly large-scale database, remains a great challenge. Here, we present a biomedical question answering framework and implement a system, Health Assistant, to enable the search process. METHODS: In Health Assistant, a search engine is firstly designed to rank biomedical documents based on contents. Then various query processing and search techniques are utilized to find the relevant documents. Afterwards, the titles and abstracts of top-N documents are extracted to generate candidate snippets. Finally, our own designed query processing and retrieval approaches for short text are applied to locate the relevant snippets to answer the questions. RESULTS: Our system is evaluated on the BioASQ benchmark datasets, and experimental results demonstrate the effectiveness and robustness of our system, compared to BioASQ participant systems and some state-of-the-art methods on both document retrieval and snippet retrieval tasks. AVAILABILITY AND IMPLEMENTATION: A demo of our system is available at https://github.com/jinzanxia/biomedical-QA.

3.
Invest Ophthalmol Vis Sci ; 60(4): 1265-1274, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30924851

RESUMO

Purpose: MicroRNA-182 (miR-182) is abundantly expressed in mammalian retinas; however, the association between miR-182 and retinal function remains unclear. In this study, we explored whether miR-182 contributes to functional decline in retinas using a miR-182 depleted mouse. Methods: Electroretinogram (ERG) amplitudes at different ages were measured in miR-182 knockout (KO) mice. The thickness and lamination of retinas were assessed using a color fundus camera and high-resolution optical coherence tomography. Expression levels of key photoreceptor-specific genes and the miR-183/96/182 cluster (miR-183C) were quantified using quantitative real-time PCR. RNA sequencing and light-induced damage were carried out to observe the changes in the retinal transcriptome and sensitivity to light damage in the miR-182 KO mice. Results: The ERG recording reveals that the ERG response amplitude decreased both at early and later ages when compared with control littermates. The expression of some key photoreceptor-specific genes was down-regulated with deletion of miR-182 in retina. RNA sequencing indicated that some biological processes of visual system were affected, and the numbers of potential target genes of miR-182 were presented in the mouse retina using bioinformatics analysis. The miR-182 KO mice were characterized by progressively losing the outer segment after being treated with light-damage exposure. The thickness and lamination of retina as well as compensatory expression of miR-183C showed no apparent changes in retina of miR-182 KO mice under normal laboratory lighting condition. Conclusions: Our findings provided new insights into the relationship between the miR-182 and retinal development and revealed that miR-182 may play a critical role in maintaining retinal function.


Assuntos
Sequência de Bases , MicroRNAs/genética , Retina/fisiopatologia , Degeneração Retiniana/genética , Deleção de Sequência , Animais , Modelos Animais de Doenças , Eletrorretinografia , Angiofluoresceinografia , Imuno-Histoquímica , Luz/efeitos adversos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Lesões Experimentais por Radiação/genética , Lesões Experimentais por Radiação/fisiopatologia , Reação em Cadeia da Polimerase em Tempo Real , Retina/efeitos da radiação , Degeneração Retiniana/fisiopatologia , Tomografia de Coerência Óptica
4.
RNA Biol ; 16(6): 821-829, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30874468

RESUMO

Circular RNAs (circRNAs) belong to an endogenous class of RNA molecules with both ends covalently linked in a circle. Although their expression pattern in the mammalian brain has been well studied, the characteristics and functions of circRNAs in retinas remain unknown. To reveal the whole expression profiles of circRNAs in the neural retina, we investigated retinal RNAs of human, monkey, mouse, pig, zebrafish and tree shrew and detected thousands of circRNAs showing conservation and variation in the retinas across different vertebrate species. We further investigated one of the abundant circRNAs, circPDE4B, identified in human retina. Silencing of circPDE4B significantly inhibited the proliferation of human A549 cells. Functional assays demonstrated that circPDE4B could sponge miR-181C, thereby altering the cell phenotype. We have explored the retinal circRNA repertoires across human and different vertebrates, which provide new insights into the important role of circRNAs in the vertebrate retinas, as well as in related human diseases.


Assuntos
/metabolismo , Retina/metabolismo , Células A549 , Animais , Linhagem Celular , Proliferação de Células/genética , Humanos , Camundongos , MicroRNAs/metabolismo , Vertebrados/genética , Vertebrados/metabolismo
5.
BMC Evol Biol ; 19(1): 35, 2019 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-30691392

RESUMO

BACKGROUND: Among the four bases, guanine is the most susceptible to damage from oxidative stress. Replication of DNA containing damaged guanines results in G to T mutations. Therefore, the mutations resulting from oxidative DNA damage are generally expected to predominantly consist of G to T (and C to A when the damaged guanine is not in the reference strand) and result in decreased GC content. However, the opposite pattern was reported 16 years ago in a study of prokaryotic genomes. Although that result has been widely cited and confirmed by nine later studies with similar methods, the omission of the effect of shared ancestry requires a re-examination of the reliability of the results. RESULTS: When aerobic and obligate aerobic prokaryotes were mixed together and anaerobic and obligate anaerobic prokaryotes were mixed together, phylogenetic controlled analyses did not detect significant difference in GC content between aerobic and anaerobic prokaryotes. This result is consistent with two generally neglected studied that had accounted for the phylogenetic relationship. However, when obligate aerobic prokaryotes were compared with aerobic prokaryotes, anaerobic prokaryotes, and obligate anaerobic prokaryotes separately using phylogenetic regression analysis, a significant positive association was observed between aerobiosis and GC content, no matter it was calculated from whole genome sequences or the 4-fold degenerate sites of protein-coding genes. Obligate aerobes have significantly higher GC content than aerobes, anaerobes, and obligate anaerobes. CONCLUSIONS: The positive association between aerobiosis and GC content could be attributed to a mutational force resulting from incorporation of damaged deoxyguanosine during DNA replication rather than oxidation of the guanine nucleotides within DNA sequences. Our results indicate a grade in the aerobiosis-associated mutational force, strong in obligate aerobes, moderate in aerobes, weak in anaerobes and obligate anaerobes.


Assuntos
Composição de Bases/genética , Células Procarióticas/metabolismo , Aerobiose , Anaerobiose , Humanos , Análise dos Mínimos Quadrados , Filogenia , Análise de Regressão , Reprodutibilidade dos Testes
6.
Proc Natl Acad Sci U S A ; 116(6): 2152-2157, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30659151

RESUMO

What kind of genetic variation contributes the most to adaptation is a fundamental question in evolutionary biology. By resequencing genomes of 80 individuals, we inferred the origin of genomic variants associated with a complex adaptive syndrome involving multiple quantitative traits, namely, adaptation between high and low altitudes, in the vinous-throated parrotbill (Sinosuthora webbiana) in Taiwan. By comparing these variants with those in the Asian mainland population, we revealed standing variation in 24 noncoding genomic regions to be the predominant genetic source of adaptation. Parrotbills at both high and low altitudes exhibited signatures of recent selection, suggesting that not only the front but also the trailing edges of postglacial expanding populations could be subjected to environmental stresses. This study verifies and quantifies the importance of standing variation in adaptation in a cohort of genes, illustrating that the evolutionary potential of a population depends significantly on its preexisting genetic diversity. These findings provide important context for understanding adaptation and conservation of species in the Anthropocene.


Assuntos
Adaptação Biológica , Evolução Biológica , Variação Genética , Aves Canoras/genética , Animais , Meio Ambiente , Genética Populacional , Genoma , Genômica/métodos , Polimorfismo de Nucleotídeo Único , RNA não Traduzido , Seleção Genética , Taiwan
7.
Xenobiotica ; 49(1): 120-126, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29394111

RESUMO

1. Cytochrome P450 3A4 (CYP3A4) is an important member of the cytochrome P450 enzyme superfamily, with 33 allelic variants reported previously. Genetic polymorphisms of CYP3A4 can produce a significant effect on the efficacy and safety of some drugs, so the purpose of this study was to clarify the catalytic characteristics of 22 CYP3A4 allelic isoforms, including 6 novel variants in Han Chinese population, on the oxidative metabolism of amiodarone in vitro. 2. Wild-type CYP3A4*1 and other variants expressed by insect cells system were incubated respectively with 10-500 µM substrate for 40 min at 37 °C and terminated at -80 °C immediately. Then these samples were treated as required and detected with ultra-performance liquid chromatography-tandem mass spectrometry used to analyze its major metabolite desethylamiodarone. 3. Among the 21 CYP3A4 variants, compared with the wild-type, the intrinsic clearance values (Vmax/Km) of two variants were apparently decreased (11.07 and 2.67% relative clearance) while twelve variants revealed markedly increased values (155.20∼435.96%), and the remaining of seven variants exhibited no significant changes in enzyme activity. 4. This is the first time report describing all these infrequent alleles for amiodarone metabolism, which can provide fundamental data for further clinical studies on CYP3A4 alleles.


Assuntos
Amiodarona/metabolismo , Inibidores do Citocromo P-450 CYP3A/metabolismo , Grupo com Ancestrais do Continente Asiático , Citocromo P-450 CYP3A/metabolismo , Humanos , Polimorfismo Genético
8.
Drug Dev Ind Pharm ; 45(1): 27-31, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30156133

RESUMO

OBJECTIVE: To investigate the impact of resveratrol on the metabolism of ibrutinib in vitro and in vivo. METHODS: In vitro, rat liver microsomes (RLM) and human liver microsomes (HLM) were used to study. In vivo, 18 male SD rats were randomly divided into three groups (n = 6): ibrutinib and the multiple dose of 100 mg/kg resveratrol for consecutive 7 days (Group A), ibrutinib and the single dose of 100 mg/kg resveratrol (Group B), ibrutinib (Group C). Processed samples were analyzed by UPLC-MS/MS. RESULTS: Resveratrol showed inhibition on RLM and HLM in vitro. The IC50 of resveratrol was 8.745 µM in RLM and 7.789 µM in HLM. Furthermore, Groups A and B both increased the AUC and reduced the CLz/F. The Cmax of Group A and the MRT(0-t) of Group B were significantly improved. CONCLUSIONS: Resveratrol inhibits the pharmacokinetic of ibrutinib in vitro and in vivo. It is necessary to pay more attention to adjust the dose of the drug when resveratrol is used in combination with ibrutinib.


Assuntos
Antioxidantes/farmacocinética , Pirazóis/farmacocinética , Pirimidinas/farmacocinética , Resveratrol/farmacocinética , Espectrometria de Massas em Tandem/métodos , Animais , Antioxidantes/análise , Cromatografia Líquida de Alta Pressão/métodos , Relação Dose-Resposta a Droga , Interações de Medicamentos/fisiologia , Humanos , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Pirazóis/análise , Pirimidinas/análise , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Resveratrol/análise
9.
Org Lett ; 20(24): 7907-7911, 2018 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-30540196

RESUMO

The first catalytic asymmetric decarboxylative [3 + 2] cycloaddition reaction of ethynylethylene carbonates with malononitrile has been developed successfully by an organo/copper cooperative system. This strategy led to a series of optically active polysubstituted dihydrofurans in good yields with high levels of enantioselectivities (up to 99% yield, 97% ee). The presence of the terminal alkynyl and the cyano group in the dihydrofuran products provides a wide scope for further structural transformations. More importantly, this organo/metal cooperative catalytic system will broaden the substrate scope and enable fundamentally new reactions.

10.
BMC Evol Biol ; 18(1): 126, 2018 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-30157765

RESUMO

BACKGROUND: Temperature is a major determinant of spontaneous mutation, but the precise mode, and the underlying mechanisms, of the temperature influences remain less clear. Here we used a mutation accumulation approach combined with whole-genome sequencing to investigate the temperature dependence of spontaneous mutation in an Escherichia coli strain. Experiments were performed under aerobic conditions at 25, 28 and 37 °C, three temperatures that were non-stressful for the bacterium but caused significantly different bacterial growth rates. RESULTS: Mutation rate did not differ between 25 and 28 °C, but was higher at 37 °C. Detailed analyses of the molecular spectrum of mutations were performed; and a particularly interesting finding is that higher temperature led to a bias of mutation to coding, relative to noncoding, DNA. Furthermore, the temperature response of mutation rate was extremely similar to that of metabolic rate, consistent with an idea that metabolic rate predicts mutation rate. CONCLUSIONS: Temperature affects mutation rate and the types of mutation supply, both being crucial for the opportunity of natural selection. Our results help understand how temperature drives evolutionary speed of organisms and thus the global patterns of biodiversity. This study also lend support to the metabolic theory of ecology for linking metabolic rate and molecular evolution rate.


Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Taxa de Mutação , Mutação/genética , Temperatura Ambiente , Pareamento de Bases/genética , Escherichia coli/crescimento & desenvolvimento , Mutação INDEL/genética
11.
PLoS One ; 13(7): e0197933, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30048461

RESUMO

Deep learning techniques, e.g., Convolutional Neural Networks (CNNs), have been explosively applied to the research in the fields of information retrieval and natural language processing. However, few research efforts have addressed semantic indexing with deep learning. The use of semantic indexing in the biomedical literature has been limited for several reasons. For instance, MEDLINE citations contain a large number of semantic labels from automatically annotated MeSH terms, and for a great deal of the literature, only the information of the title and the abstract is readily available. In this paper, we propose a Boltzmann Convolutional neural network framework (B-CNN) for biomedicine semantic indexing. In our hybrid learning framework, the CNN can adaptively deal with features of documents that have sequence relationships, and can capture context information accordingly; the Deep Boltzmann Machine (DBM) merges global (the entity in each document) and local information through its training with undirected connections. Additionally, we have designed a hierarchical coarse to fine style indexing structure for learning and classifying documents, and a novel feature extension approach with word sequence embedding and Wikipedia categorization. Comparative experiments were conducted for semantic indexing of biomedical abstract documents; these experiments verified the encouraged performance of our B-CNN model.


Assuntos
Aprendizado de Máquina , Processamento de Linguagem Natural , Humanos , Armazenamento e Recuperação da Informação , MEDLINE , Publicações Periódicas como Assunto , Semântica
12.
Exp Mol Med ; 50(4): 53, 2018 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-29700284

RESUMO

Ocular coloboma is a developmental structural defect of the eye that often occurs as complex ocular anomalies. However, its genetic etiology remains largely unexplored. Here we report the identification of mutation (c.331C>T, p.R111C) in the IPO13 gene in a consanguineous family with ocular coloboma, microphthalmia, and cataract by a combination of whole-exome sequencing and homozygosity mapping. IPO13 encodes an importin-B family protein and has been proven to be associated with the pathogenesis of coloboma and microphthalmia. We found that Ipo13 was expressed in the cornea, sclera, lens, and retina in mice. Additionally, the mRNA expression level of Ipo13 decreased significantly in the patient compared with its expression in a healthy individual. Morpholino-oligonucleotide-induced knockdown of ipo13 in zebrafish caused dose-dependent microphthalmia and coloboma, which is highly similar to the ocular phenotypes in the patient. Moreover, both visual motor response and optokinetic response were impaired severely. Notably, these ocular phenotypes in ipo13-deficient zebrafish could be rescued remarkably by full-length ipo13 mRNA, suggesting that the phenotypes observed in zebrafish were due to insufficient ipo13 function. Altogether, our findings demonstrate, for the first time, a new role of IPO13 in eye morphogenesis and that loss of function of IPO13 could lead to ocular coloboma, microphthalmia, and cataract in humans and zebrafish.

13.
Basic Clin Pharmacol Toxicol ; 122(4): 383-387, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29117640

RESUMO

Cytochrome P450 3A4 (CYP3A4) is quantitatively the most important P450 enzyme in adults. It is suggested that CYP3A4 genetic polymorphisms may influence the rate of the metabolism and elimination of CYP3A4 substrates in human beings. Ibrutinib is an anticancer drug and primarily metabolized by CYP3A4. The aim of this study was to systematically investigate the effects of 22 CYP3A4 protein variants on the metabolism of ibrutinib in vitro. When compared with wild-type CYP3A4.1, two variants (CYP3A4.17 and CYP3A4.24) had no detectable enzyme activity; five variants (CYP3A4.10, .11, .18, .23 and .33) exhibited no significant differences; another five variants (CYP3A4.3, .4, .9, .19 and .34) showed increased intrinsic clearance values, while the remaining nine variants (CYP3A4.2, .5, .14, .15, .16, .28, .29, .31 and .32) displayed decreased enzymatic activities in different degrees. As the first study of 22 CYP3A4 protein variants in ibrutinib metabolism, these comprehensive data may help in the clinical assessment of the metabolism and elimination of ibrutinib and also offer a reference to the personalized treatment of ibrutinib in clinic.


Assuntos
Antineoplásicos/metabolismo , Citocromo P-450 CYP3A/genética , Pirazóis/metabolismo , Pirimidinas/metabolismo , Antineoplásicos/uso terapêutico , Citocromo P-450 CYP3A/metabolismo , Ensaios Enzimáticos , Humanos , Transtornos Linfoproliferativos/tratamento farmacológico , Microssomos/enzimologia , Polimorfismo Genético , Medicina de Precisão/métodos , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
14.
New Phytol ; 217(4): 1726-1736, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29178135

RESUMO

Whether species demography and diversification are driven primarily by extrinsic environmental changes such as climatic oscillations in the Quaternary or by intrinsic biological interactions like coevolution between antagonists is a matter of active debate. In fact, their relative importance can be assessed by tracking past population fluctuations over considerable time periods. We applied the pairwise sequentially Markovian coalescent approach on the genomes of 11 temperate Juglans species to estimate trajectories of changes in effective population size (Ne ) and used a Bayesian-coalescent based approach that simultaneously considers multiple genomes (G-PhoCS) to estimate divergence times between lineages. Ne curves of all study species converged 1.0 million yr ago, probably reflecting the time when the walnut genus last shared a common ancestor. This estimate was confirmed by the G-PhoCS estimates of divergence times. But all species did not react similarly to the dramatic climatic oscillations following early Pleistocene cooling, so the timing and amplitude of changes in Ne differed among species and even among conspecific lineages. The population histories of temperate walnut species were not driven by extrinsic environmental changes alone, and a key role was probably played by species-specific factors such as coevolutionary interactions with specialized pathogens.


Assuntos
Mudança Climática , Variação Genética , Genoma de Planta , Juglans/genética , Sequenciamento Completo do Genoma , Sequência de Bases , Fraxinus/genética , Cadeias de Markov , Filogenia , Densidade Demográfica , Populus/genética , Especificidade da Espécie , Fatores de Tempo
15.
Int J Mol Sci ; 17(2)2016 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-26840300

RESUMO

MicroRNAs (miRNAs), a class of single stranded, small (~22 nucleotides), non-coding RNAs, play an important role in muscle development. We focused on the role of the miR-30-5p family during bovine muscle development from previous high-throughput sequencing results and analyzed their expression profiles. MHC and MyoG mRNAs expression as well as their proteins were suppressed in differentiated C2C12 cells, suggesting the importance of miR-30-5p in muscle development. MBNL, the candidate target of miR-30-5p, is an alternative splicing regulation factor. MBNL1 and MBNL3 have opposite effects on muscle differentiation. Our results confirmed that miR-30a-5p and miR-30e-5p repress the expression of MBNL1, MBNL2 and MBNL3, whereas miR-30b-5p inhibits MBNL1 and MBNL2 expression. This provides direct evidence that MBNL expression can be flexibly regulated by miR-30-5p. Previous studies showed that MBNL1 promotes exon inclusion of two muscle-related genes (Trim55 and INSR). Through RNA splicing studies, we found that miR-30-5p had an effect on their alternative splicing, which means miR-30-5p via MBNL1 could be integrated into muscle signaling pathways in which INSR or Trim55 are located. In conclusion, miR-30-5p could inhibit muscle cell differentiation and regulate the alternative splicing of Trim55 and INSR by targeting MBNL. These results promote the understanding of the function of miRNAs in muscle development.


Assuntos
Processamento Alternativo , MicroRNAs/genética , Desenvolvimento Muscular , Proteínas Musculares/genética , Proteínas de Ligação a RNA/metabolismo , Animais , Bovinos , Regulação da Expressão Gênica no Desenvolvimento , Células HEK293 , Humanos , Camundongos , Proteínas Musculares/metabolismo , Proteínas de Ligação a RNA/genética
16.
PLoS One ; 11(2): e0148479, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26863545

RESUMO

Effective book search has been discussed for decades and is still future-proof in areas as diverse as computer science, informatics, e-commerce and even culture and arts. A variety of social information contents (e.g, ratings, tags and reviews) emerge with the huge number of books on the Web, but how they are utilized for searching and finding books is seldom investigated. Here we develop an Integrated Search And Recommendation Technology (IsArt), which breaks new ground by providing a generic framework for searching books with rich social information. IsArt comprises a search engine to rank books with book contents and professional metadata, a Generalized Content-based Filtering model to thereafter rerank books with user-generated social contents, and a learning-to-rank technique to finally combine a wide range of diverse reranking results. Experiments show that this technology permits embedding social information to promote book search effectiveness, and IsArt, by making use of it, has the best performance on CLEF/INEX Social Book Search Evaluation datasets of all 4 years (from 2011 to 2014), compared with some other state-of-the-art methods.


Assuntos
Livros , Bases de Dados Bibliográficas , Ferramenta de Busca , Algoritmos , Árvores de Decisões , Internet , Linguagens de Programação , Software
17.
Stand Genomic Sci ; 10: 125, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26664654

RESUMO

Escherichia coli lab strains K-12 GM4792 Lac(+) and GM4792 Lac(-) carry opposite lactose markers, which are useful for distinguishing evolved lines as they produce different colored colonies. The two closely related strains are chosen as ancestors for our ongoing studies of experimental evolution. Here, we describe the genome sequences, annotation, and features of GM4792 Lac(+) and GM4792 Lac(-). GM4792 Lac(+) has a 4,622,342-bp long chromosome with 4,061 protein-coding genes and 83 RNA genes. Similarly, the genome of GM4792 Lac(-) consists of a 4,621,656-bp chromosome containing 4,043 protein-coding genes and 74 RNA genes. Genome comparison analysis reveals that the differences between GM4792 Lac(+) and GM4792 Lac(-) are minimal and limited to only the targeted lac region. Moreover, a previous study on competitive experimentation indicates the two strains are identical or nearly identical in survivability except for lactose utilization in a nitrogen-limited environment. Therefore, at both a genetic and a phenotypic level, GM4792 Lac(+) and GM4792 Lac(-), with opposite neutral markers, are ideal systems for future experimental evolution studies.

18.
Inorg Chem ; 54(11): 5266-72, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25989178

RESUMO

One novel three-dimensional (3D) 3d-4f metal-organic framework (MOF), [TbZn(L)(CO3)2(H2O)]n (1) [HL = 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine], has been successfully synthesized and structurally characterized. Structural analysis shows that compound 1 features a unique chiral interpenetrating 3D framework for the first time. The resulting crystals of 1 are composed of enantiomers 1a (P41) and 1b (P43), as was clearly confirmed by the crystal structure and the corresponding circular dichroism (CD) analyses of eight randomly selected crystals. The investigations on CD spectra based on every single crystal clearly assigned the Cotton effect signals. The powder X-ray diffraction measurement of 1 after being immersed in common solvents reveals that 1 possess excellent solvent stability. Furthermore, luminescent studies imply that 1 displays highly selective luminescent sensing of aldehydes, such as formol, acetaldehyde, and propanal.

19.
Dalton Trans ; 43(44): 16838-45, 2014 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-25293936

RESUMO

Two novel tetra- and deca-nuclear dysprosium compounds, namely, [Dy4(µ3-OH)2(L)10(bipy)2(H2O)2]n (1) and {[Dy10(µ3-OH)8(L)22(bipy)2(H2O)2]·5H2O}n (2) (L = 3-fluoro-4-(trifluoromethyl)benzoic acid; bipy = 2,2'-bipyridine), have been successfully obtained by hydrothermal reaction at different pH values. The solid state structures of 1 and 2 were established by the single crystal X-ray diffraction technique, and both of them exhibit complicated 1D chains with [Dy4] (1) and [Dy10] (2) cluster units, respectively. Adjacent [Dy4] in 1 and [Dy10] in 2 are connected by two bridging carboxylate groups in the η(1):η(1):µ2 mode. Magnetic studies reveal that they exhibit different magnetic relaxation behaviors with the energy barrier of 23.6 K for 1 and 3.2 K for 2. Interestingly, the large divergence in both the structures and magnetic properties for 1 and 2 only originated from the different pH values in preparing them.

20.
Sci China Life Sci ; 57(2): 188-94, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24448906

RESUMO

Due to the low number of collectable stem cells from single umbilical cord blood (UCB) unit, their initial uses were limited to pediatric therapies. Clinical applications of UCB hematopoietic stem and progenitor cells (HSPCs) would become feasible if there were a culture method that can effectively expand HSPCs while maintaining their self-renewal capacity. In recent years, numerous attempts have been made to expand human UCB HSPCs in vitro. In this study, we report that caffeic acid phenethyl ester (CAPE), a small molecule from honeybee extract, can promote in vitro expansion of HSPCs. Treatment with CAPE increased the percentage of HSPCs in cultured mononuclear cells. Importantly, culture of CD34(+) HSPCs with CAPE resulted in a significant increase in total colony-forming units and high proliferative potential colony-forming units. Burst-forming unit-erythroid was the mostly affected colony type, which increased more than 3.7-fold in 1 µg mL(-1) CAPE treatment group when compared to the controls. CAPE appears to induce HSPC expansion by upregulating the expression of SCF and HIF1-α. Our data suggest that CAPE may become a potent medium supplement for in vitro HSPC expansion.


Assuntos
Ácidos Cafeicos/farmacologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Álcool Feniletílico/análogos & derivados , Cordão Umbilical/efeitos dos fármacos , Células Cultivadas , Citometria de Fluxo , Células-Tronco Hematopoéticas/citologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Técnicas In Vitro , Álcool Feniletílico/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Células-Tronco/metabolismo , Cordão Umbilical/citologia , Regulação para Cima/efeitos dos fármacos
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