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1.
J Biol Phys ; 43(4): 511-524, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28887655

RESUMO

DNA samples are commonly frozen for storage. However, freezing can compromise the integrity of DNA molecules. Considering the wide applications of DNA molecules in nanotechnology, changes to DNA integrity at the molecular level may cause undesirable outcomes. However, the effects of freezing on DNA integrity have not been fully explored. To investigate the impact of freezing on DNA integrity, samples of frozen and non-frozen bacteriophage lambda DNA were studied using optical tweezers. Tension (5-35 pN) was applied to DNA molecules to mimic mechanical interactions between DNA and other biomolecules. The integrity of the DNA molecules was evaluated by measuring the time taken for single DNA molecules to break under tension. Mean lifetimes were determined by maximum likelihood estimates and variances were obtained through bootstrapping simulations. Under 5 pN of force, the mean lifetime of frozen samples is 44.3 min with 95% confidence interval (CI) between 36.7 min and 53.6 min while the mean lifetime of non-frozen samples is 133.2 min (95% CI: 97.8-190.1 min). Under 15 pN of force, the mean lifetimes are 10.8 min (95% CI: 7.6-12.6 min) and 78.5 min (95% CI: 58.1-108.9 min). The lifetimes of frozen DNA molecules are significantly reduced, implying that freezing compromises DNA integrity. Moreover, we found that the reduced DNA structural integrity cannot be restored using regular ligation process. These results indicate that freezing can alter the structural integrity of the DNA molecules.


Assuntos
DNA Viral/química , Congelamento , Estresse Mecânico , Bacteriófago lambda/genética , Pinças Ópticas
2.
J Biol Chem ; 285(31): 23655-64, 2010 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-20511234

RESUMO

Homodimeric H(+)-pyrophosphatase (H(+)-PPase; EC 3.6.1.1) is a unique enzyme playing a pivotal physiological role in pH homeostasis of organisms. This novel H(+)-PPase supplies energy at the expense of hydrolyzing metabolic byproduct, pyrophosphate (PP(i)), for H(+) translocation across membrane. The functional unit for the translocation is considered to be a homodimer. Its putative active site on each subunit consists of PP(i) binding motif, Acidic I and II motifs, and several essential residues. In this investigation structural mapping of these vital regions was primarily determined utilizing single molecule fluorescence resonance energy transfer. Distances between two C termini and also two N termini on homodimeric subunits of H(+)-PPase are 49.3 + or - 4.0 and 67.2 + or - 5.7 A, respectively. Furthermore, putative PP(i) binding motifs on individual subunits are found to be relatively far away from each other (70.8 + or - 4.8 A), whereas binding of potassium and substrate analogue led them to closer proximity. Moreover, substrate analogue but not potassium elicits significant distance variations between two Acidic I motifs and two His-622 residues on homodimeric subunits. Taken together, this study provides the first quantitative measurements of distances between various essential motifs, residues, and putative active sites on homodimeric subunits of H(+)-PPase. A working model is accordingly proposed elucidating the distance variations of dimeric H(+)-PPase upon substrate binding.


Assuntos
Transferência Ressonante de Energia de Fluorescência/métodos , Pirofosfatase Inorgânica/química , Pirofosfatase Inorgânica/fisiologia , Pirofosfatases/química , Motivos de Aminoácidos , Domínio Catalítico , Clostridium tetani/enzimologia , Dimerização , Escherichia coli/enzimologia , Ligantes , Microssomos/metabolismo , Mutação , Sinais Direcionadores de Proteínas , Transporte Proteico , Espectrometria de Fluorescência
3.
J Cell Physiol ; 226(9): 2338-49, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21660957

RESUMO

Honokiol (HNK) is a phenolic compound isolated from the bark of houpu (Magnolia officinalis), a plant widely used in traditional Chinese and Japanese medicine. While substantial evidence indicates that HNK possesses anti-inflammatory activity, its effect on dendritic cells (DCs) during the inflammatory reaction remains unclear. The present study investigates how HNK affects lipopolysaccharide (LPS)-stimulated human monocyte-derived DCs. Our experimental results show that HNK inhibits the inflammatory response of LPS-induced DCs by (1) suppressing the expression of CD11c, CD40, CD80, CD83, CD86, and MHC-II on LPS-activated DCs, (2) reducing the production of TNF-α, IL-1ß, IL-6, and IL-12p70 but increasing the production of IL-10 and TGF-ß1 by LPS-activated DCs, (3) inhibiting the LPS-induced DC-elicited allogeneic T-cell proliferation, and (4) shifting the LPS-induced DC-driven Th1 response toward a Th2 response. Further, our results show that HNK inhibits the phosphorylation levels of ERK1/2, p38, JNK1/2, IKKα, and IκBα in LPS-activated DCs. Collectively, the findings show that the anti-inflammatory actions of HNK on LPS-induced DCs are associated with the NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways.


Assuntos
Compostos de Bifenilo/farmacologia , Diferenciação Celular/efeitos dos fármacos , Células Dendríticas/citologia , Células Dendríticas/imunologia , Inflamação/patologia , Lignanas/farmacologia , Lipopolissacarídeos/farmacologia , Monócitos/citologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citocinas/biossíntese , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/enzimologia , Endocitose/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Fenótipo , Células Th1/citologia , Células Th1/efeitos dos fármacos , Células Th1/metabolismo , Células Th2/citologia , Células Th2/efeitos dos fármacos , Células Th2/metabolismo
4.
Sci Total Environ ; 757: 143766, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33243507

RESUMO

Organic particle dynamics in the surface ocean plays a critical part in the marine carbon cycle. Aggregation of marine organic particles drives their downward transport to support various marine organisms on their transit to the sediments. Extracellular polymeric substances (EPS) from various microbes are a major contributor to the oceanic organic particle pool. The stickiness of EPS is expected to play a determining role in the aggregation process of particles; however, stickiness parameters are usually indirectly estimated through data fitting without direct assessment. Here a magnetic tweezer method was developed to quantitatively assess the stickiness of three model EPS produced by: Amphora sp., (diatom), Emiliania huxleyi (coccolithophore), and Sagittula stellata (bacteria), under different in vitro environmental conditions (salinity or EDTA complexed cations) and surface matrices (EPS-EPS and bare glass). Our results showed the stickiness of three microbial EPS decreasing for S. stellata > E. huxleyi > Amphora sp., in line with their decreasing protein-to-carbohydrate (P/C) ratios (related to their relative hydrophobicity). The data not only emphasize the importance of hydrophobicity on EPS stickiness, but also demonstrates that salinity and the nature of the substrate surface can influence the stickiness. Furthermore, we investigated stickiness between various types of EPS, and the observed selective stickiness of EPS between species may shed light on the interactions among heterogeneous marine microorganisms. Overall, this newly developed system provides a platform to assess the EPS stickiness to advance our understanding of the aggregation and sedimentation process of organic particles that are critical for the fate of organic carbon as well as for biofilm formation and microbial colonization of surfaces in the ocean.


Assuntos
Diatomáceas , Rhodobacteraceae , Matriz Extracelular de Substâncias Poliméricas , Fenômenos Magnéticos
5.
BMC Bioinformatics ; 11: 421, 2010 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-20698961

RESUMO

BACKGROUND: Over the past decade, gene expression microarray studies have greatly expanded our knowledge of genetic mechanisms of human diseases. Meta-analysis of substantial amounts of accumulated data, by integrating valuable information from multiple studies, is becoming more important in microarray research. However, collecting data of special interest from public microarray repositories often present major practical problems. Moreover, including low-quality data may significantly reduce meta-analysis efficiency. RESULTS: M2DB is a human curated microarray database designed for easy querying, based on clinical information and for interactive retrieval of either raw or uniformly pre-processed data, along with a set of quality-control metrics. The database contains more than 10,000 previously published Affymetrix GeneChip arrays, performed using human clinical specimens. M2DB allows online querying according to a flexible combination of five clinical annotations describing disease state and sampling location. These annotations were manually curated by controlled vocabularies, based on information obtained from GEO, ArrayExpress, and published papers. For array-based assessment control, the online query provides sets of QC metrics, generated using three available QC algorithms. Arrays with poor data quality can easily be excluded from the query interface. The query provides values from two algorithms for gene-based filtering, and raw data and three kinds of pre-processed data for downloading. CONCLUSION: M2DB utilizes a user-friendly interface for QC parameters, sample clinical annotations, and data formats to help users obtain clinical metadata. This database provides a lower entry threshold and an integrated process of meta-analysis. We hope that this research will promote further evolution of microarray meta-analysis.


Assuntos
Bases de Dados Genéticas , Análise de Sequência com Séries de Oligonucleotídeos , Algoritmos , Perfilação da Expressão Gênica , Humanos , Internet , Metanálise como Assunto , Controle de Qualidade , Software , Interface Usuário-Computador , Vocabulário Controlado
6.
Forensic Sci Res ; 5(1): 55-63, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32490311

RESUMO

Seeds, the reproductive organs of plants, are common as trace evidence from crime scenes. Seed evidence could be grouped into several categories based on the types of crimes they are associated with, including child abuse, homicides and drugs. Most commonly, seeds are examined microscopically and identified to the plant species level to show a linkage between persons and places. More recently, forensic researchers have evaluated the potential for extracting and typing DNA from seeds to further individualize the samples. As a model system, tomato seeds were examined microscopically after different cooking treatments and assessed for the potential to DNA type seeds for variety identification. A sufficient quantity and quality of DNA were recovered from uncooked, digested and undigested tomato seeds for amplified fragment length polymorphism (AFLP) analysis; however, any form of cooking destroyed the seed DNA. A simple microscopic analysis was able to distinguish between a cooked tomato seed versus an uncooked seed. This article is intended to provide an overview of case examples and current techniques for the forensic examination of seeds as plant-derived evidence.

7.
Radiat Res ; 171(6): 716-24, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19580478

RESUMO

Ultraviolet B (UVB) radiation has strong biological effects and modulates the expression of many genes. The major biological pathways affected by UVB radiation remain controversial. In this work, we used a loop-design microarray approach and applied rigorous statistical analyses to identify differentially regulated genes at 4, 8, 16 or 24 h after UVB irradiation. The most prominent biological categories in lists of differentially regulated gene sets were extracted by functional enrichment analysis. With this approach, we determined that genes participating in two prime cellular processes, the ribosome pathway and the oxidative phosphorylation pathway, were persistently activated after UVB irradiation. Mitochondrial activity assays confirmed increased activity for up to 24 h after UVB irradiation. These results suggest that the persistent activation of ribosome and oxidative phosphorylation pathways may have a key role in UVB-radiation-induced cellular responses. For the first time, the specific cellular pathways that respond to UVB radiation consistently and persistently can be delineated with confidence using a loop-design microarray approach and functional bioinformatics analysis. The results of this study offer further insight into UVB-radiation-induced stress responses.


Assuntos
Expressão Gênica/efeitos da radiação , Fosforilação Oxidativa/efeitos da radiação , Ribossomos/genética , Transdução de Sinais/genética , Raios Ultravioleta , Linhagem Celular , Humanos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Reação em Cadeia da Polimerase , Ribossomos/metabolismo , Fatores de Tempo
8.
In Vitro Cell Dev Biol Anim ; 54(8): 589-599, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30083841

RESUMO

Application of high-dosage UVB irradiation in phototherapeutic dermatological treatments present health concerns attributed to UV-exposure. In assessing UV-induced photobiological damage, we investigated dose-dependent effects of UVB irradiation on human keratinocyte cells (HaCaT). Our study implemented survival and apoptosis assays and revealed an unexpected dose response wherein higher UVB-dosage induced higher viability. Established inhibitors, such as AKT- (LY294002), PKC- (Gö6976, and Rottlerin), ERK- (PD98059), P38 MAPK- (SB203580), and JNK- (SP600125), were assessed to investigate UV-induced apoptotic pathways. Despite unobvious contributions of known signaling pathways in dose-response mediation, microarray analysis identified transcriptional expression of UVB-response genes related to the respiratory-chain. Observed correlation of ROS-production with UVB irradiation potentiated ROS as the underlying mechanism for observed dose responses. Inability of established pathways to explain such responses suggests the complex nature underlying UVB-phototherapy response.


Assuntos
Queratinócitos/efeitos da radiação , Raios Ultravioleta , Acetofenonas/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Benzopiranos/farmacologia , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , Transporte de Elétrons/efeitos da radiação , Flavonoides/farmacologia , Perfilação da Expressão Gênica , Humanos , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Óxido Nítrico/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/metabolismo , Transcrição Gênica/efeitos dos fármacos , Transcrição Gênica/efeitos da radiação , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/efeitos da radiação
9.
Artigo em Inglês | MEDLINE | ID: mdl-27200105

RESUMO

We investigated the syndromes of the Sini decoction pattern (SDP), a common ZHENG in traditional Chinese medicine (TCM). The syndromes of SDP were correlated with various severe Yang deficiency related symptoms. To obtain a common profile for SDP, we distributed questionnaires to 300 senior clinical TCM practitioners. According to the survey, we concluded 2 sets of symptoms for SDP: (1) pulse feels deep or faint and (2) reversal cold of the extremities. Twenty-four individuals from Taipei City Hospital, Linsen Chinese Medicine Branch, Taiwan, were recruited. We extracted the total mRNA of peripheral blood mononuclear cells from the 24 individuals for microarray experiments. Twelve individuals (including 6 SDP patients and 6 non-SDP individuals) were used as the training set to identify biomarkers for distinguishing the SDP and non-SDP groups. The remaining 12 individuals were used as the test set. The test results indicated that the gene expression profiles of the identified biomarkers could effectively distinguish the 2 groups by adopting a hierarchical clustering algorithm. Our results suggest the feasibility of using the identified biomarkers in facilitating the diagnosis of TCM ZHENGs. Furthermore, the gene expression profiles of biomarker genes could provide a molecular explanation corresponding to the ZHENG of TCM.

11.
PLoS One ; 9(11): e111719, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25372711

RESUMO

Detecting periodicity signals from time-series microarray data is commonly used to facilitate the understanding of the critical roles and underlying mechanisms of regulatory transcriptomes. However, time-series microarray data are noisy. How the temporal data structure affects the performance of periodicity detection has remained elusive. We present a novel method based on empirical mode decomposition (EMD) to examine this effect. We applied EMD to a yeast microarray dataset and extracted a series of intrinsic mode function (IMF) oscillations from the time-series data. Our analysis indicated that many periodically expressed genes might have been under-detected in the original analysis because of interference between decomposed IMF oscillations. By validating a protein complex coexpression analysis, we revealed that 56 genes were newly determined as periodic. We demonstrated that EMD can be used incorporating with existing periodicity detection methods to improve their performance. This approach can be applied to other time-series microarray studies.


Assuntos
Perfilação da Expressão Gênica/métodos , Conjuntos de Dados como Assunto , Redes Reguladoras de Genes , Oxirredução , Reprodutibilidade dos Testes , Leveduras/genética , Leveduras/metabolismo
12.
PLoS One ; 9(11): e113424, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25409520

RESUMO

Following an increase in the use of electric appliances that can generate 50 or 60 Hz electromagnetic fields, concerns have intensified regarding the biological effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on human health. Previous epidemiological studies have suggested the carcinogenic potential of environmental exposure to ELF-EMFs, specifically at 50 or 60 Hz. However, the biological mechanism facilitating the effects of ELF-EMFs remains unclear. Cellular studies have yielded inconsistent results regarding the biological effects of ELF-EMFs. The inconsistent results might have been due to diverse cell types. In our previous study, we indicated that 1.5 mT, 60 Hz ELF-EMFs will cause G1 arrest through the activation of the ATM-Chk2-p21 pathway in human keratinocyte HaCaT cells. The aim of the current study was to investigate whether ELF-EMFs cause similar effects in a distinct epidermal keratinocyte, primary normal human epidermal keratinocytes (NHEK), by using the same ELF-EMF exposure system and experimental design. We observed that ELF-EMFs exerted no effects on cell growth, cell proliferation, cell cycle distribution, and the activation of ATM signaling pathway in NHEK cells. We demonstrated that the 2 epidermal keratinocytes responded to ELF-EMFs differently. To further validate this finding, we simultaneously exposed the NHEK and HaCaT cells to ELF-EMFs in the same incubator for 168 h and observed the cell growths. The simultaneous exposure of the two cell types results showed that the NHEK and HaCaT cells exhibited distinct responses to ELF-EMFs. Thus, we confirmed that the biological effects of ELF-EMFs in epidermal keratinocytes are cell type specific. Our findings may partially explain the inconsistent results of previous studies when comparing results across various experimental models.


Assuntos
Campos Eletromagnéticos , Queratinócitos/efeitos da radiação , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proliferação de Células/efeitos da radiação , Células Cultivadas , Quinase do Ponto de Checagem 2/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Células Epidérmicas , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos da radiação , Humanos , Peróxido de Hidrogênio/toxicidade , Queratinócitos/citologia , Queratinócitos/metabolismo , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação , Raios Ultravioleta
13.
PLoS One ; 9(9): e108162, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25244160

RESUMO

Radiation therapy for cancer patients works by ionizing damage to nuclear DNA, primarily by creating double-strand breaks (DSB). A major shortcoming of traditional radiation therapy is the set of side effect associated with its long-range interaction with nearby tissues. Low-energy Auger electrons have the advantage of an extremely short effective range, minimizing damage to healthy tissue. Consequently, the isotope 99mTc, an Auger electron source, is currently being studied for its beneficial potential in cancer treatment. We examined the dose effect of a pyrene derivative 99mTc complex on plasmid DNA by using gel electrophoresis in both aqueous and methanol solutions. In aqueous solutions, the average yield per decay for double-strand breaks is 0.011±0.005 at low dose range, decreasing to 0.0005±0.0003 in the presence of 1 M dimethyl sulfoxide (DMSO). The apparent yield per decay for single-strand breaks (SSB) is 0.04±0.02, decreasing to approximately a fifth with 1 M DMSO. In methanol, the average yield per decay of DSB is 0.54±0.06 and drops to undetectable levels in 2 M DMSO. The SSB yield per decay is 7.2±0.2, changing to 0.4±0.2 in the presence of 2 M DMSO. The 95% decrease in the yield of DSB in DMSO indicates that the main mechanism for DSB formation is through indirect effect, possibly by cooperative binding or clustering of intercalators. In the presence of non-radioactive ligands at a near saturation concentration, where radioactive Tc compounds do not form large clusters, the yield of SSB stays the same while the yield of DSB decreases to the value in DMSO. DSBs generated by 99mTc conjugated to intercalators are primarily caused by indirect effects through clustering.


Assuntos
Dano ao DNA , DNA/efeitos dos fármacos , Compostos de Organotecnécio/farmacologia , Pirenos/farmacologia , Eletroforese em Gel de Ágar , Soluções , Água
14.
PLoS One ; 9(8): e104732, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25111195

RESUMO

In daily life, humans are exposed to the extremely low-frequency electromagnetic fields (ELF-EMFs) generated by electric appliances, and public concern is increasing regarding the biological effects of such exposure. Numerous studies have yielded inconsistent results regarding the biological effects of ELF-EMF exposure. Here we show that ELF-EMFs activate the ATM-Chk2-p21 pathway in HaCaT cells, inhibiting cell proliferation. To present well-founded results, we comprehensively evaluated the biological effects of ELF-EMFs at the transcriptional, protein, and cellular levels. Human HaCaT cells from an immortalized epidermal keratinocyte cell line were exposed to a 1.5 mT, 60 Hz ELF-EMF for 144 h. The ELF-EMF could cause G1 arrest and decrease colony formation. Protein expression experiments revealed that ELF-EMFs induced the activation of the ATM/Chk2 signaling cascades. In addition, the p21 protein, a regulator of cell cycle progression at G1 and G2/M, exhibited a higher level of expression in exposed HaCaT cells compared with the expression of sham-exposed cells. The ELF-EMF-induced G1 arrest was diminished when the CHK2 gene expression (which encodes checkpoint kinase 2; Chk2) was suppressed by specific small interfering RNA (siRNA). These findings indicate that ELF-EMFs activate the ATM-Chk2-p21 pathway in HaCaT cells, resulting in cell cycle arrest at the G1 phase. Based on the precise control of the ELF-EMF exposure and rigorous sham-exposure experiments, all transcriptional, protein, and cellular level experiments consistently supported the conclusion. This is the first study to confirm that a specific pathway is triggered by ELF-EMF exposure.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quinase do Ponto de Checagem 2/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Campos Eletromagnéticos/efeitos adversos , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos da radiação , Transdução de Sinais/efeitos da radiação , Linhagem Celular , Proliferação de Células/efeitos da radiação , Humanos , Transcriptoma/efeitos da radiação
15.
PLoS One ; 8(9): e73311, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24019915

RESUMO

Simian virus 40 (SV40) transforms cells through the suppression of tumor-suppressive responses by large T and small t antigens; studies on the effects of these two oncoproteins have greatly improved our knowledge of tumorigenesis. Large T antigen promotes cellular transformation by binding and inactivating p53 and pRb tumor suppressor proteins. Previous studies have shown that not all of the tumor-suppressive responses were inactivated in SV40-transformed cells; however, the underlying cause is not fully studied. In this study, we investigated the UVB-responsive transcriptome of an SV40-transformed fibroblast (MRC5CVI) and that of its untransformed counterpart (MRC-5). We found that, in response to UVB irradiation, MRC-5 and MRC5CVI commonly up-regulated the expression of oxidative phosphorylation genes. MRC-5 up-regulated the expressions of chromosome condensation, DNA repair, cell cycle arrest, and apoptotic genes, but MRC5CVI did not. Further cell death assays indicated that MRC5CVI was more sensitive than MRC-5 to UVB-induced cell death with increased caspase-3 activation; combining with the transcriptomic results suggested that MRC5CVI may undergo UVB-induced cell death through mechanisms other than transcriptional regulation. Our study provides a further understanding of the effects of SV40 transformation on cellular stress responses, and emphasizes the value of SV40-transformed cells in the researches of sensitizing neoplastic cells to radiations.


Assuntos
Perfilação da Expressão Gênica , Transcriptoma , Raios Ultravioleta , Apoptose , Ciclo Celular , Linhagem Celular Transformada , Reparo do DNA , Fibroblastos/efeitos da radiação , Humanos
16.
J Biol Phys ; 38(1): 113-20, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23277674

RESUMO

Water molecules play critical roles in many biological functions, such as protein dynamics, enzymatic activities, and cellular responses. Previous nuclear magnetic resonance and neutron scattering studies have shown that water molecules bind to specific sites on surfaces and form localized clusters. However, most current experimental techniques cannot measure dynamic behaviors of ordered water molecules on cell-size (10 µm) scale. Recently, the long-distance effect of structured water has been demonstrated by Pollack and his colleagues. Namely, there is a structured water layer near the hydrophilic surface that can exclude solutes (Zheng et al, Adv Colloid Interface Sci 127:19-27, 2006; Pollack 2006, Adv Colloid Interface Sci 103:173-196, 2003). The repelling forces of water clusters inside this exclusion region are investigated in this study. With a laser tweezers system, we found the existence of an unexpected force fields inside the solute-free exclusion zone near a Nafion surface. Our results suggest that the water clusters could transduce mechanical signals on the micrometer range within the exclusion zone. This unexpected inhomogeneous force field near the hydrophilic surface would provide a new insight into cellular activities, leading to a potential new physical chemistry mechanism for cell biology.

17.
Acta Biomater ; 8(7): 2504-16, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22484717

RESUMO

Although various cell encapsulation materials are available commercially for a wide range of potential therapeutic cells, their combined clinical impact remains inconsistent. Synthetic materials such as poly(ethylene glycol) (PEG) hydrogels are mechanically robust and have been extensively explored but lack natural biofunctionality. Naturally derived materials including collagen, fibrin and alginate-chitosan are often labile and mechanically weak. In this paper we report the development of a hybrid biomatrix based on the thiol-ene reaction of PEG diacrylate (PEGdA) and cysteine/PEG-modified gelatin (gel-PEG-Cys). We hypothesized that covalent crosslinking decreases gelatin dissolution thus increasing gelatin resident time within the matrix and the duration of its biofunctionality; at the same time the relative ratio of PEGdA to gel-PEG-Cys in the matrix formulation directly affects hydrogel bulk and local microenvironment properties. Bulk viscoelastic properties were highly dependent on PEGdA concentration and total water content, while gel-PEG-Cys concentration was more critical to swelling profiles. Microviscoelastic properties were related to polymer concentration. The covalently crosslinked gel-PEG-Cys with PEGdA decreased gelatin dissolution out of the matrix and collagenase-mediated degradation. Fibroblasts and keratinocyte increased adhesion density and formed intercellular connections on stiffer hydrogel surfaces, while cells exhibited more cytoplasmic spreading and proliferation when entrapped within softer hydrogels. Hence, this material system contains multiparametric factors that can easily be controlled to modulate the chemical, physical and biological properties of the biomatrix for soft tissue scaffolding and cell presentation to reconstruct lost tissue architecture and physical functionality.


Assuntos
Materiais Biocompatíveis/farmacologia , Técnicas de Cultura de Células/métodos , Fibroblastos/citologia , Queratinócitos/citologia , Compostos de Sulfidrila/farmacologia , Animais , Bovinos , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Imobilizadas/citologia , Células Imobilizadas/efeitos dos fármacos , Cisteína/farmacologia , Dextranos/metabolismo , Elasticidade/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluoresceína-5-Isotiocianato/metabolismo , Gelatina/síntese química , Gelatina/química , Humanos , Queratinócitos/efeitos dos fármacos , Cinética , Teste de Materiais , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Proteólise/efeitos dos fármacos , Ratos , Reologia/efeitos dos fármacos , Soluções , Propriedades de Superfície/efeitos dos fármacos , Sus scrofa , Viscosidade/efeitos dos fármacos
18.
Comput Biol Med ; 42(2): 228-34, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22188791

RESUMO

A number of recent studies have shown that loop-design is more efficient than reference control design. Data analysis for loop-design microarray experiments is commonly undertaken using linear models and statistical tests. These techniques require specialized knowledge in statistical programming. However, limited loop-design web-based tools are available. We have developed the THEME (Tsing Hua Engine of Microarray Experiment) that exploits all necessary data analysis tools for loop-design microarray studies. THEME allows users to construct linear models and to apply multiple user-defined statistical tests of hypotheses for detection of DEG (differentially expressed genes). Users can modify entries of design matrix for experimental design as well as that of contrast matrix for statistical tests of hypotheses. The output of multiple user-defined statistical tests of hypotheses, DEG lists, can be cross-validated. The web platform provides data assessment and visualization tools that significantly assist users when evaluating the performance of microarray experimental procedures. THEME is also a MIAME (Minimal Information About a Microarray Experiment) compliant system, which enables users to export formatted files for GEO (Gene Expression Omnibus) submission. THEME offers comprehensive web services to biologists for data analysis of loop-design microarray experiments. This web-based resource is especially useful for core facility service as well as collaboration projects when researchers are not at the same site. Data analysis procedures, starting from uploading raw data files to retrieving DEG lists, can be flexibly operated with natural workflows. These features make THEME a reliable and powerful on-line system for data analysis of loop-design microarrays. The THEME server is available at http://metadb.bmes.nthu.edu.tw/theme/.


Assuntos
Biologia Computacional/métodos , Perfilação da Expressão Gênica/métodos , Internet , Software , Bases de Dados Genéticas , Modelos Lineares , Análise em Microsséries/métodos
19.
PLoS One ; 7(6): e38650, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22723873

RESUMO

BACKGROUND: Variance in microarray studies has been widely discussed as a critical topic on the identification of differentially expressed genes; however, few studies have addressed the influence of estimating variance. METHODOLOGY/PRINCIPAL FINDINGS: To break intra- and inter-individual variance in clinical studies down to three levels--technical, anatomic, and individual--we designed experiments and algorithms to investigate three forms of variances. As a case study, a group of "inter-individual variable genes" were identified to exemplify the influence of underestimated variance on the statistical and biological aspects in identification of differentially expressed genes. Our results showed that inadequate estimation of variance inevitably led to the inclusion of non-statistically significant genes into those listed as significant, thereby interfering with the correct prediction of biological functions. Applying a higher cutoff value of fold changes in the selection of significant genes reduces/eliminates the effects of underestimated variance. CONCLUSIONS/SIGNIFICANCE: Our data demonstrated that correct variance evaluation is critical in selecting significant genes. If the degree of variance is underestimated, "noisy" genes are falsely identified as differentially expressed genes. These genes are the noise associated with biological interpretation, reducing the biological significance of the gene set. Our results also indicate that applying a higher number of fold change as the selection criteria reduces/eliminates the differences between distinct estimations of variance.


Assuntos
Perfilação da Expressão Gênica , Adulto , Biologia Computacional/métodos , Feminino , Regulação da Expressão Gênica , Variação Genética , Humanos , Placenta/metabolismo , Gravidez
20.
PLoS One ; 7(7): e40824, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22829888

RESUMO

Cordyceps sinensis (CS) has been commonly used as herbal medicine and a health supplement in China for over two thousand years. Although previous studies have demonstrated that CS has benefits in immunoregulation and anti-inflammation, the precise mechanism by which CS affects immunomodulation is still unclear. In this study, we exploited duplicate sets of loop-design microarray experiments to examine two different batches of CS and analyze the effects of CS on dendritic cells (DCs), in different physiology stages: naïve stage and inflammatory stage. Immature DCs were treated with CS, lipopolysaccharide (LPS), or LPS plus CS (LPS/CS) for two days, and the gene expression profiles were examined using cDNA microarrays. The results of two loop-design microarray experiments showed good intersection rates. The expression level of common genes found in both loop-design microarray experiments was consistent, and the correlation coefficients (Rs), were higher than 0.96. Through intersection analysis of microarray results, we identified 295 intersecting significantly differentially expressed (SDE) genes of the three different treatments (CS, LPS, and LPS/CS), which participated mainly in the adjustment of immune response and the regulation of cell proliferation and death. Genes regulated uniquely by CS treatment were significantly involved in the regulation of focal adhesion pathway, ECM-receptor interaction pathway, and hematopoietic cell lineage pathway. Unique LPS regulated genes were significantly involved in the regulation of Toll-like receptor signaling pathway, systemic lupus erythematosus pathway, and complement and coagulation cascades pathway. Unique LPS/CS regulated genes were significantly involved in the regulation of oxidative phosphorylation pathway. These results could provide useful information in further study of the pharmacological mechanisms of CS. This study also demonstrates that with a rigorous experimental design, the biological effects of a complex compound can be reliably studied by a complex system like cDNA microarray.


Assuntos
Cordyceps/química , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Perfilação da Expressão Gênica/métodos , Células Cultivadas , Humanos , Lipopolissacarídeos/farmacologia , Análise de Sequência com Séries de Oligonucleotídeos
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