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1.
Sci Rep ; 13(1): 7705, 2023 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-37173356

RESUMO

Harmony search (HS) is a new swarm intelligent algorithm inspired by the process of music improvisation. Over the past decade, HS algorithm has been applied to many practical engineering problems. However, for some complex practical problems, there are some remaining issues such as premature convergence, low optimization accuracy and slow convergence speed. To address these issues, this paper proposes a novel intelligent global harmony search algorithm based on improved search stability strategy (NIGHS). In the search process, NIGHS uses the adaptive mean of harmony memory library to build a stable trust region around the global best harmony, and proposes a new coupling operation based on linear proportional relation, so that the algorithm can adaptively adjust the ability of exploration and exploitation in the search process and avoid premature convergence. In addition, the dynamic Gauss fine-tuning is adopted in the stable trust region to accelerate the convergence speed and improve the optimization accuracy. The common CEC2017 test functions are employed to test the proposed algorithm, the results show that NIGHS algorithm has a faster convergence speed and better optimization accuracy compared to the HS algorithm and its improved versions.

2.
Eur Radiol ; 33(5): 3435-3443, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36920520

RESUMO

OBJECTIVES: To evaluate a deep learning model for automated and interpretable classification of central canal stenosis, neural foraminal stenosis, and facet arthropathy from lumbar spine MRI. METHODS: T2-weighted axial MRI studies of the lumbar spine acquired between 2008 and 2019 were retrospectively selected (n = 200) and graded for central canal stenosis, neural foraminal stenosis, and facet arthropathy. Studies were partitioned into patient-level train (n = 150), validation (n = 20), and test (n = 30) splits. V-Net models were first trained to segment the dural sac and the intervertebral disk, and localize facet and foramen using geometric rules. Subsequently, Big Transfer (BiT) models were trained for downstream classification tasks. An interpretable model for central canal stenosis was also trained using a decision tree classifier. Evaluation metrics included linearly weighted Cohen's kappa score for multi-grade classification and area under the receiver operator characteristic curve (AUROC) for binarized classification. RESULTS: Segmentation of the dural sac and intervertebral disk achieved Dice scores of 0.93 and 0.94. Localization of foramen and facet achieved intersection over union of 0.72 and 0.83. Multi-class grading of central canal stenosis achieved a kappa score of 0.54. The interpretable decision tree classifier had a kappa score of 0.80. Pairwise agreement between readers (R1, R2), (R1, R3), and (R2, R3) was 0.86, 0.80, and 0.74. Binary classification of neural foraminal stenosis and facet arthropathy achieved AUROCs of 0.92 and 0.93. CONCLUSION: Deep learning systems can be performant as well as interpretable for automated evaluation of lumbar spine MRI including classification of central canal stenosis, neural foraminal stenosis, and facet arthropathy. KEY POINTS: • Interpretable deep-learning systems can be developed for the evaluation of clinical lumbar spine MRI. Multi-grade classification of central canal stenosis with a kappa of 0.80 was comparable to inter-reader agreement scores (0.74, 0.80, 0.86). Binary classification of neural foraminal stenosis and facet arthropathy achieved favorable and accurate AUROCs of 0.92 and 0.93, respectively. • While existing deep-learning systems are opaque, leading to clinical deployment challenges, the proposed system is accurate as well as interpretable, providing valuable information to a radiologist in clinical practice.


Assuntos
Aprendizado Profundo , Disco Intervertebral , Artropatias , Estenose Espinal , Humanos , Estenose Espinal/diagnóstico por imagem , Constrição Patológica , Estudos Retrospectivos , Imageamento por Ressonância Magnética , Vértebras Lombares/diagnóstico por imagem
3.
Molecules ; 28(3)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36770808

RESUMO

Isolates of a variety of fungal plant pathogens (Alternaria radicina ICMP 5619, Cercospora beticola ICMP 15907, Dactylonectria macrodidyma ICMP 16789, D. torresensis ICMP 20542, Ilyonectria europaea ICMP 16794, and I. liriodendra ICMP 16795) were screened for antimicrobial activity against the human pathogenic bacteria Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, Mycobacterium abscessus, and M. marinum and were found to have some activity. Investigation of the secondary metabolites of these fungal isolates led to the isolation of ten natural products (1-10) of which one was novel, (E)-4,7-dihydroxyoct-2-enoic acid (1). Structure elucidation of all natural products was achieved by a combination of NMR spectroscopy and mass spectrometry. We also investigated the antimicrobial activity of a number of the isolated natural products. While we did not find (E)-4,7-dihydroxyoct-2-enoic acid (1) to have any activity against the bacteria and fungi in our assays, we did find that cercosporin (7) exhibited potent activity against Methicillin resistant Staphylococcus aureus (MRSA), dehydro-curvularin (6) and radicicol (10) exhibited antimycobacterial activity against M. marinum, and brefeldin A (8) and radicicol (10) exhibited antifungal activity against Candida albicans. Investigation of the cytotoxicity and haemolytic activities of these natural products (6-8 and 10) found that only one of the four active compounds, radicicol (10), was non-cytotoxic and non-haemolytic.


Assuntos
Anti-Infecciosos , Produtos Biológicos , Staphylococcus aureus Resistente à Meticilina , Humanos , Produtos Biológicos/farmacologia , Anti-Infecciosos/farmacologia , Fungos , Antibacterianos/química , Bactérias , Candida albicans , Plantas , Testes de Sensibilidade Microbiana
4.
Sci Rep ; 12(1): 21176, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36476639

RESUMO

Many real-world engineering problems need to balance different objectives and can be formatted as multi-objective optimization problem. An effective multi-objective algorithm can achieve a set of optimal solutions that can make a tradeoff between different objectives, which is valuable to further explore and design. In this paper, an improved multi-objective differential evolution algorithm (MOEA/D/DEM) based on a decomposition strategy is proposed to improve the performance of differential evolution algorithm for practical multi-objective nutrition decision problems. Firstly, considering the neighborhood characteristic, a neighbor intimacy factor is designed in the search process for enhancing the diversity of the population, then a new Gaussian mutation strategy with variable step size is proposed to reduce the probability of escaping local optimum area and improve the local search ability. Finally, the proposed algorithm is tested by classic test problems (DTLZ1-7 and WFG1-9) and applied to the multi-objective nutrition decision problems, compared to the other reported multi-objective algorithms, the proposed algorithm has a better search capability and obtained competitive results.

5.
Antibiotics (Basel) ; 11(10)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36290109

RESUMO

Antibiotics have been the cornerstone of modern medicine saving lives by virtue of being able to cure infectious diseases and to prevent infections in those who are immune compromised. Their intense use has led to a surging increase in the incidence of antibiotic-resistant bacteria resulting in a desperate need for antibiotics with new mechanisms of action. As part of our search for new antimicrobials we have screened an in-house library of compounds and identified two 3-substituted-1H-imidazol-5-yl-1H-indoles as weak growth inhibitors (MIC 16 µg/mL) against methicillin-resistant Staphylococcus aureus (MRSA). An extensive library of analogues was prepared using the Van Leusen three-component reaction, biological evaluation of which led to the identification of two analogues (26 and 32) with favorable anti-MRSA activity (MIC ≤ 0.25 µg/mL) which also lacked cytotoxic or hemolytic properties. The screening campaign also identified two derivatives, a phenethyl-indole-imidazole 57 and a 5-phenyl-1H-imidazole 111 that were non-toxic selective antifungals towards Cryptococcus neoformans. These results have identified 3-substituted-1H-imidazol-5-yl-1H-indoles and 5-phenyl-1H-imidazoles as new structural scaffolds for further investigation as anti-MRSA and anti-C. neoformans agents, respectively.

6.
Bioorg Med Chem ; 64: 116762, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35477062

RESUMO

As part of our search for new antimicrobials and antibiotic adjuvants, a series of podocarpic acid-polyamine conjugates have been synthesized. The library of compounds made use of the phenolic and carboxylic acid moieties of the diterpene allowing attachment of polyamines (PA) of different lengths to afford a structurally-diverse set of analogues. Evaluation of the conjugates for intrinsic antimicrobial properties identified two derivatives of interest: a PA3-4-3 (spermine) amide-bonded variant 7a that was a non-cytotoxic, non-hemolytic potent growth inhibitor of Gram-positive Staphylococcus aureus (MRSA) and 9d, a PA3-8-3 carbamate derivative that was a non-toxic selective antifungal towards Cryptococcus neoformans. Of the compound set, only one example exhibited activity towards Gram-negative bacteria. However, in the presence of sub-therapeutic amounts of either doxycycline (4.5 µM) or erythromycin (2.7 µM) several analogues were observed to exhibit weak to modest antibiotic adjuvant properties against Pseudomonas aeruginosa and/or Escherichia coli. The observation of strong cytotoxicity and/or hemolytic properties for subsets of the library, in particular those analogues bearing methyl ester or n-pentylamide functionality, highlighted the fine balance of structural requirements and lipophilicity for antimicrobial activity as opposed to mammalian cell toxicity.


Assuntos
Antibacterianos , Anti-Infecciosos , Abietanos , Adjuvantes Farmacêuticos/farmacologia , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Escherichia coli , Mamíferos , Testes de Sensibilidade Microbiana , Poliaminas/química , Poliaminas/farmacologia , Relação Estrutura-Atividade
7.
Mol Cancer Res ; 19(12): 2046-2056, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34521764

RESUMO

Strengthened DNA repair pathways in tumor cells contribute to the development of resistance to DNA-damaging agents. Consequently, targeting proteins in these pathways is a promising strategy for tumor chemosensitization. Here, we show that the expression of a subset of Fanconi anemia (FA) genes is attenuated in glioblastoma tumor cells deficient in methylthioadenosine phosphorylase (MTAP), a common genetic alteration in a variety of cancers. Subsequent experiments in cell line models of different cancer types illustrate that this reduced transcription of FA genes can be recapitulated by blockage of Protein Arginine Methyltransferase 5 (PRMT5), a promising therapeutically targetable epigenetic regulator whose enzymatic activity is compromised in MTAP-deficient cells. Further analyses provide evidence to support that PRMT5 can function as an epigenetic regulator that contributes to the increased expression of FA genes in cancer cells. Most notably and consistent with the essential roles of FA proteins in resolving DNA damage elicited by interstrand crosslinking (ICL) agents, PRMT5 blockage, as well as MTAP loss, sensitizes tumor cells to ICL agents both in vitro and in xenografts. Collectively, these findings reveal a novel epigenetic mechanism underlying the upregulated expression of FA genes in cancer cells and suggest that therapeutically targeting PRMT5 can have an additional benefit of chemosensitizing tumor cells to ICL agents. IMPLICATIONS: PRMT5 positively regulates the expression of FA genes. Inhibition of PRMT5 attenuates FA-dependent DNA repair pathway and sensitizes tumor cells to ICL agents.


Assuntos
Epigênese Genética/genética , Anemia de Fanconi/genética , Expressão Gênica/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Masculino , Camundongos , Camundongos Nus
8.
ChemMedChem ; 16(3): 513-523, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33090655

RESUMO

The discovery of new antibiotic adjuvants is an attractive option for overcoming antimicrobial resistance. We have previously reported the discovery of a bis-6-bromoindolglyoxylamide derivative of spermine as being able to enhance the action of antibiotics against Gram-negative bacteria but suffers from being cytotoxic and red-blood cell haemolytic. A series of analogues was prepared exploring variation of the indolglyoxylamide unit, to include indole-3-acrylic, indole-3-acetic and indole-3-carboxylate units, and evaluated for antibiotic enhancing properties against a range of Gram-negative bacteria, and for intrinsic antimicrobial, cytotoxic and haemolytic properties. Two spermine derivatives, bearing 5-bromo-indole-3-acetic acid (17) and 5-methoxy-indole-3-acrylic acid (14) end groups were found to exhibit good to moderate antibiotic adjuvant activities for doxycycline towards the Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae, but with more modest intrinsic antimicrobial activity and greatly reduced cytotoxic and haemolytic properties. The mechanism of action of the latter derivative identified its ability to disrupt the outer membranes of bacteria and to inhibit the AcrAB-TolC efflux pump directly or by inhibiting the proton gradient.


Assuntos
Antibacterianos/farmacologia , Ácidos Indolacéticos/farmacologia , Indóis/farmacologia , Espermina/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Ácidos Indolacéticos/química , Indóis/química , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Espermina/síntese química , Espermina/química , Relação Estrutura-Atividade
9.
Molecules ; 25(11)2020 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-32545320

RESUMO

In an effort to gain more understanding on the structure activity relationship of pseudoceratidine 1, a di-bromo pyrrole spermidine alkaloid derived from the marine sponge Pseudoceratina purpurea that has been shown to exhibit potent biofouling, anti-fungal, antibacterial, and anti-malarial activities, a large series of 65 compounds that incorporated several aspects of structural variation has been synthesised through an efficient, divergent method that allowed for a number of analogues to be generated from common precursors. Subsequently, all analogues were assessed for their antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Overall, several compounds exhibited comparable or better activity than that of pseudoceratidine 1, and it was found that this class of compounds is generally more effective against Gram-positive than Gram-negative bacteria. Furthermore, altering several structural features allowed for the establishment of a comprehensive structure activity relationship (SAR), where it was concluded that several structural features are critical for potent anti-bacterial activity, including di-halogenation (preferable bromine, but chlorine is also effective) on the pyrrole ring, two pyrrolic units in the structure and with one or more secondary amines in the chain adjoining these units, with longer chains giving rise to better activities.


Assuntos
Alcaloides/síntese química , Antibacterianos/síntese química , Produtos Biológicos/química , Poríferos/química , Alcaloides/química , Alcaloides/farmacologia , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Halogenação , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
10.
Artigo em Inglês | MEDLINE | ID: mdl-34804348

RESUMO

At NASA Goddard Space Flight Center, we have been developing spaceborne lidar instruments for space sciences. We have successfully flown several missions in the past based on mature diode pumped solid-state laser transmitters. In recent years, we have been developing advanced laser technologies for applications such as laser spectroscopy, laser communications, and interferometry. In this article, we will discuss recent experimental progress on these systems and instrument prototypes for ongoing development.

11.
Bioorg Med Chem ; 27(10): 2090-2099, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30975502

RESUMO

The combination of increased incidence of drug-resistant strains of bacteria and a lack of novel drugs in development creates an urgency for the search for new antimicrobials. Initial screening of compounds from an in-house library identified two 6-bromoindolglyoxylamide polyamine derivatives (3 and 4) that exhibited intrinsic antimicrobial activity towards Gram-positive bacteria, Staphylococcus aureus and S. intermedius with polyamine 3 also displaying in vitro antibiotic enhancing properties against the resistant Gram-negative bacterium Pseudomonas aeruginosa. A series of 6-bromo derivatives (5-15) were prepared and biologically evaluated, identifying analogues with enhanced antibacterial activity towards Escherichia coli and with moderate to excellent antifungal properties. Polyamine 3, which includes a spermine chain, was the most potent of the series - its mechanism of action was attributed to rapid membrane permeabilization and depolarization in both Gram-positive and Gram-negative bacteria.


Assuntos
Antibacterianos/química , Anti-Infecciosos/química , Poliaminas/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Linhagem Celular , Sobrevivência Celular , Farmacorresistência Bacteriana/efeitos dos fármacos , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Fungos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Indóis/química , Testes de Sensibilidade Microbiana , Poliaminas/farmacologia
12.
J Biosoc Sci ; 51(3): 418-435, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30289091

RESUMO

The effects of marriage between biological relatives on the incidence of childhood genetic illness and mortality are of major policy significance, as rates of consanguinity exceed 50% in various countries. Empirical research on this question is complicated by the fact that consanguinity is often correlated with poverty and other unobserved characteristics of households, which may have independent effects on mortality. This study has developed an instrumental variables empirical strategy to re-examine this question, based on the concept that the availability of unmarried cousins of the opposite gender at the time of marriage creates quasi-random variation in the propensity to marry consanguineously. Using primary data collected in Bangladesh in 2006-07 and Pakistan in 2009-10, the study found that previous estimates of the impact of consanguinity on child health were biased and falsely precise. The study also empirically investigated the social and economic causes of consanguinity (including marital quality) and concludes that marrying a cousin can have positive economic effects for one's natal family, by allowing deferral of dowry payments until after marriage.


Assuntos
Consanguinidade , Nível de Saúde , Fatores Socioeconômicos , Bangladesh , Criança , Saúde da Criança/estatística & dados numéricos , Correlação de Dados , Feminino , Doenças Genéticas Inatas/epidemiologia , Doenças Genéticas Inatas/mortalidade , Humanos , Masculino , Casamento , Paquistão , Taxa de Sobrevida
13.
J Natl Cancer Inst ; 111(7): 664-674, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30423141

RESUMO

BACKGROUND: The LKB1 tumor suppressor gene is commonly inactivated in non-small cell lung carcinomas (NSCLC), a major form of lung cancer. Targeted therapies for LKB1-inactivated lung cancer are currently unavailable. Identification of critical signaling components downstream of LKB1 inactivation has the potential to uncover rational therapeutic targets. Here we investigated the role of INSL4, a member of the insulin/IGF/relaxin superfamily, in LKB1-inactivated NSCLCs. METHODS: INSL4 expression was analyzed using global transcriptome profiling, quantitative reverse transcription PCR, western blotting, enzyme-linked immunosorbent assay, and RNA in situ hybridization in human NSCLC cell lines and tumor specimens. INSL4 gene expression and clinical data from The Cancer Genome Atlas lung adenocarcinomas (n = 515) were analyzed using log-rank and Fisher exact tests. INSL4 functions were studied using short hairpin RNA (shRNA) knockdown, overexpression, transcriptome profiling, cell growth, and survival assays in vitro and in vivo. All statistical tests were two-sided. RESULTS: INSL4 was identified as a novel downstream target of LKB1 deficiency and its expression was induced through aberrant CRTC-CREB activation. INSL4 was highly induced in LKB1-deficient NSCLC cells (up to 543-fold) and 9 of 41 primary tumors, although undetectable in all normal tissues except the placenta. Lung adenocarcinomas from The Cancer Genome Atlas with high and low INSL4 expression (with the top 10th percentile as cutoff) showed statistically significant differences for advanced tumor stage (P < .001), lymph node metastasis (P = .001), and tumor size (P = .01). The INSL4-high group showed worse survival than the INSL4-low group (P < .001). Sustained INSL4 expression was required for the growth and viability of LKB1-inactivated NSCLC cells in vitro and in a mouse xenograft model (n = 5 mice per group). Expression profiling revealed INSL4 as a critical regulator of cell cycle, growth, and survival. CONCLUSIONS: LKB1 deficiency induces an autocrine INSL4 signaling that critically supports the growth and survival of lung cancer cells. Therefore, aberrant INSL4 signaling is a promising therapeutic target for LKB1-deficient lung cancers.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteínas Serina-Treonina Quinases/genética , Transcriptoma/genética , Células A549 , Quinases Proteína-Quinases Ativadas por AMP , Animais , Comunicação Autócrina/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Proliferação de Células/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Masculino , Camundongos , Transdução de Sinais/genética , Fatores de Transcrição/genética , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Mol Immunol ; 87: 86-93, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28412548

RESUMO

Over the past decades, a number of prolactin receptor (PRLR) antagonists have been developed, which can be divided into two categories, PRLR analogue and anti-PRLR antibody. However, until now, there have been no commercially available PRLR antagonists. Here, we described a new approach for the preparation of PRLR antagonist, namely internal image anti-idiotypic antibody strategy. The hybridoma technique was used to generate anti-idiotypic antibodies to PRL. Competitive ELISA, competitive receptor-binding analysis and immunofluorescence assay (IFA) were then used to screen and characterize anti-idiotypic antibodies to PRL. One internal image anti-idiotypic antibody, termed MG7, was obtained. A series of experiments demonstrated that MG7 behaved as a typical internal image anti-idiotypic antibody (Ab2ß). MG7 exhibited effective antagonistic activity, which not only inhibited PRL binding to PRLR in a dose-dependent manner but also inhibited PRLR-mediated intracellular signalling. Furthermore, MG7 also blocked Nb2 cell proliferation induced by PRL. The current study suggests that MG7 has the potential application in the PRL/PRLR-related studies in future. In addition, this work also suggests that the internal image anti-idiotypic antibody may represent a novel strategy for the development of PRLR antagonist.


Assuntos
Anticorpos Anti-Idiotípicos/imunologia , Receptores da Prolactina/antagonistas & inibidores , Receptores da Prolactina/imunologia , Animais , Anticorpos Monoclonais/imunologia , Ligação Competitiva/imunologia , Células CHO , Proliferação de Células/fisiologia , Cricetinae , Cricetulus , Hibridomas/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Fosforilação/imunologia , Prolactina/imunologia , Ligação Proteica/imunologia , Transdução de Sinais/imunologia
15.
Int J Biochem Cell Biol ; 68: 101-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26369868

RESUMO

In general, traditional growth hormone receptor antagonist can be divided into two major classes: growth hormone (GH) analogues and anti-growth hormone receptor (GHR) antibodies. Herein, we tried to explore a new class of growth hormone receptor (GHR) antagonist that may have potential advantages over the traditional antagonists. For this, we developed a monoclonal anti-idiotypic antibody growth hormone, termed CG-86. A series of experiments were conducted to characterize and evaluate this antibody, and the results from a competitive receptor-binding assay, Enzyme Linked Immunosorbent Assays (ELISA) and epitope mapping demonstrate that CG-86 behaved as a typical Ab2ß. Next, we examined its antagonistic activity using in vitro cell models, and the results showed that CG-86 could effectively inhibit growth hormone receptor-mediated signalling and effectively inhibit growth hormone-induced Ba/F3-GHR638 proliferation. In summary, these studies show that an anti-idiotypic antibody (CG-86) has promise as a novel growth hormone receptor antagonist. Furthermore, the current findings also suggest that anti-idiotypic antibody may represent a novel strategy to produce a new class of growth hormone receptor antagonist, and this strategy may be applied with other cytokines or growth factors.


Assuntos
Anticorpos Monoclonais/farmacologia , Hormônio do Crescimento/metabolismo , Receptores da Somatotropina/antagonistas & inibidores , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/química , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Ligação Competitiva , Células CHO , Linhagem Celular , Proliferação de Células , Cricetulus , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos , Expressão Gênica , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/imunologia , Ratos , Receptores da Somatotropina/genética , Receptores da Somatotropina/imunologia , Transdução de Sinais
16.
Proc Natl Acad Sci U S A ; 112(39): 12175-80, 2015 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-26324907

RESUMO

Although natural products have been a particularly rich source of human medicines, activity-based screening results in a very high rate of rediscovery of known molecules. Based on the large number of natural product biosynthetic genes in microbial genomes, many have proposed "genome mining" as an alternative approach for discovery efforts; however, this idea has yet to be performed experimentally on a large scale. Here, we demonstrate the feasibility of large-scale, high-throughput genome mining by screening a collection of over 10,000 actinomycetes for the genetic potential to make phosphonic acids, a class of natural products with diverse and useful bioactivities. Genome sequencing identified a diverse collection of phosphonate biosynthetic gene clusters within 278 strains. These clusters were classified into 64 distinct groups, of which 55 are likely to direct the synthesis of unknown compounds. Characterization of strains within five of these groups resulted in the discovery of a new archetypical pathway for phosphonate biosynthesis, the first (to our knowledge) dedicated pathway for H-phosphinates, and 11 previously undescribed phosphonic acid natural products. Among these compounds are argolaphos, a broad-spectrum antibacterial phosphonopeptide composed of aminomethylphosphonate in peptide linkage to a rare amino acid N(5)-hydroxyarginine; valinophos, an N-acetyl l-Val ester of 2,3-dihydroxypropylphosphonate; and phosphonocystoximate, an unusual thiohydroximate-containing molecule representing a new chemotype of sulfur-containing phosphonate natural products. Analysis of the genome sequences from the remaining strains suggests that the majority of the phosphonate biosynthetic repertoire of Actinobacteria has been captured at the gene level. This dereplicated strain collection now provides a reservoir of numerous, as yet undiscovered, phosphonate natural products.


Assuntos
Actinobacteria/química , Actinobacteria/genética , Produtos Biológicos/química , Descoberta de Drogas/tendências , Genoma Bacteriano/genética , Genômica/métodos , Ácidos Fosforosos/análise , Sequência de Bases , Descoberta de Drogas/métodos , Biblioteca Gênica , Genômica/tendências , Dados de Sequência Molecular , Análise de Sequência de DNA
17.
Int J Mol Sci ; 13(8): 10143-10153, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22949852

RESUMO

The epigenetic effects on DNA methylation, histone modification, and expression of non-coding RNAs (including microRNAs) of environmental chemicals such as bisphenol A (BPA) and phthalates have expanded our understanding of the etiology of human complex diseases such as cancers and diabetes. Multiple lines of evidence from in vitro and in vivo models have established that epigenetic modifications caused by in utero exposure to environmental toxicants can induce alterations in gene expression that may persist throughout life. Epigenetics is an important mechanism in the ability of environmental chemicals to influence health and disease, and BPA and phthalates are epigenetically toxic. The epigenetic effect of BPA was clearly demonstrated in viable yellow mice by decreasing CpG methylation upstream of the Agouti gene, and the hypomethylating effect of BPA was prevented by maternal dietary supplementation with a methyl donor like folic acid or the phytoestrogen genistein. Histone H3 was found to be trimethylated at lysine 27 by BPA effect on EZH2 in a human breast cancer cell line and mice. BPA exposure of human placental cell lines has been shown to alter microRNA expression levels, and specifically, miR-146a was strongly induced by BPA treatment. In human breast cancer MCF7 cells, treatment with the phthalate BBP led to demethylation of estrogen receptor (ESR1) promoter-associated CpG islands, indicating that altered ESR1 mRNA expression by BBP is due to aberrant DNA methylation. Maternal exposure to phthalate DEHP was also shown to increase DNA methylation and expression levels of DNA methyltransferases in mouse testis. Further, some epigenetic effects of BPA and phthalates in female rats were found to be transgenerational. Finally, the available new technologies for global analysis of epigenetic alterations will provide insight into the extent and patterns of alterations between human normal and diseased tissues. In vitro models such as human embryonic stem cells may be extremely useful in bettering the understanding of epigenetic effects on human development, health and disease, because the formation of embryoid bodies in vitro is very similar to the early stage of embryogenesis.


Assuntos
Compostos Benzidrílicos/farmacologia , Epigênese Genética , Regulação da Expressão Gênica/efeitos dos fármacos , Fenóis/farmacologia , Ácidos Ftálicos/farmacologia , Animais , Metilação de DNA , Feminino , Humanos , Camundongos , Regiões Promotoras Genéticas , Ratos
18.
J Acoust Soc Am ; 132(1): 507-17, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22779497

RESUMO

Based on the Gabor transform, a metric is developed and applied to automatically identify bird species from a sample of 568 digital recordings of songs/calls from 67 species of birds. The Gabor frequency-amplitude spectrum and the Gabor time-amplitude profile are proposed as a means to characterize the frequency and time patterns of a bird song. An approach based on template matching where unknown song clips are compared to a library of known song clips is used. After adding noise to simulate the background environment and using an adaptive high-pass filter to de-noise the recordings, the successful identification rate exceeded 93% even at signal-to-noise ratios as low as 5 dB. Bird species whose songs/calls were dominated by low frequencies were more difficult to identify than species whose songs were dominated by higher frequencies. The results suggest that automated identification may be practical if comprehensive libraries of recordings that encompass the vocal variation within species can be assembled.


Assuntos
Ruído , Aves Canoras/fisiologia , Vocalização Animal/fisiologia , Animais , Análise de Fourier , Mascaramento Perceptivo/fisiologia , Espectrografia do Som , Fatores de Tempo
19.
Methods Mol Biol ; 873: 127-49, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22528352

RESUMO

Human embryonic stem cell (hESC) lines have been derived from the inner cell mass of blastocysts. Five hESC lines have been derived from 32 discarded blastocysts in Taiwan, and these lines have since been continuously cultured on mitotically inactivated mouse embryonic fibroblasts as feeder in the hESC medium for more than 44 passages and underwent freezing/thawing processes. All of five hESC lines expressed characteristic undifferentiated hESC markers such as SSEA-4, TRA-1-81, alkaline phosphatase, TERT, transcription factors POU5F1 (OCT4), and NANOG. The hESC lines T1 and T3 possess normal female karyotypes, whereas lines T4 and T5 are normal male, but line T2 is male trisomy 12 (47XY,+12). The hESC lines T1, T2, T3, and T5 were able to produce teratomas in SCID mice, and line T4 could only form embryoid bodies in vitro. Global gene expression profiles of single colonies of these five hESC lines were analyzed using Affymetrix human genome U133 plus 2.0 GeneChip. The results showed that 4,145 transcripts, including 19% of unknown functions, were detected in all five hESC lines. Comparison of the 4,145 genes commonly expressed in the five hESC lines with those genes expressed in teratoma produced by hESC line T1 and placenta revealed 40 genes exclusively expressed in all five hESC lines. These 40 genes include the previously reported stemness genes such as POU5F1 (OCT4), NANOG, TDGF1 (CRIPTO), SALL4, LECT1, and BUB1 responsible for self-renewal and pluripotent differentiation. The global gene expression analysis also indicated that the TGFß/activin branch components inhibin BC, ACVR2A, ACVR1 (ALK2), TGFBR1 (ALK5), and SMAD2 were found to be highly expressed in undifferentiated states of these five hESC lines and decreased upon differentiation. The epigenetic states and expression of 32 known imprinted genes in these five hESC lines and/or differentiated derivatives were also investigated. In short, the hESC nature of these five hESC lines is supported by the undifferentiated state, extensive renewal capacity, and pluripotency, including the ability to form teratomas and/or embryoid bodies; and these cell lines will be useful for research on human embryonic stem cell biology and drug development/toxicity testing. The epigenetic states and expression of imprinted genes in hESC lines should be thoroughly studied after extended culture and upon differentiation in order to understand epigenetic stability in hESC lines before their clinical applications.


Assuntos
Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Perfilação da Expressão Gênica/métodos , Linhagem Celular , Feminino , Humanos , Cariótipo , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Taiwan
20.
Gene ; 494(1): 85-91, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22173104

RESUMO

Plastics are widely used in modern life, and their unbound chemicals bisphenol A and phthalates can leach out into the surrounding environment. BPA and PAEs have recently attracted the special attention of the scientific community, regulatory agencies and the general public because of their high production volume, widespread use of plastics, and endocrine-disrupting effects. In The Comparative Toxicogenomics Database, BPA and five most frequently curated PAEs (DEHP/MEHP and DBP/BBP/MBP) were found to have 1932 and 484 interactions with genes/proteins, respectively. Five of their top ten toxicity networks were found to be involved in inflammation, and their top ten diseases included genital, prostatic, endomentrial, ovarian and breast diseases. BPA and PAEs were found to exhibit similar toxicogenomics and adverse effects on human health owning to their 89 common interacting genes/proteins. These 89 genes/proteins may serve as biomarkers to assay the toxicities of different chemicals leached out from the widely used plastics.


Assuntos
Fenóis/toxicidade , Ácidos Ftálicos/toxicidade , Compostos Benzidrílicos , Bases de Dados como Assunto , Exposição Ambiental , Humanos , Inflamação/induzido quimicamente , Toxicogenética
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