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1.
Environ Sci Technol ; 58(22): 9525-9535, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38758591

RESUMO

While the ecological role that Trichodesmium sp. play in nitrogen fixation has been widely studied, little information is available on potential specialized metabolites that are associated with blooms and standing stock Trichodesmium colonies. While a collection of biological material from a T. thiebautii bloom event from North Padre Island, Texas, in 2014 indicated that this species was a prolific producer of chlorinated specialized metabolites, additional spatial and temporal resolution was needed. We have completed these metabolite comparison studies, detailed in the current report, utilizing LC-MS/MS-based molecular networking to visualize and annotate the specialized metabolite composition of these Trichodesmium blooms and colonies in the Gulf of Mexico (GoM) and other waters. Our results showed that T. thiebautii blooms and colonies found in the GoM have a remarkably consistent specialized metabolome. Additionally, we isolated and characterized one new macrocyclic compound from T. thiebautii, trichothilone A (1), which was also detected in three independent cultures of T. erythraeum. Genome mining identified genes predicted to synthesize certain functional groups in the T. thiebautii metabolites. These results provoke intriguing questions of how these specialized metabolites affect Trichodesmium ecophysiology, symbioses with marine invertebrates, and niche development in the global oligotrophic ocean.


Assuntos
Trichodesmium , Trichodesmium/metabolismo , Golfo do México , Cianobactérias/metabolismo , Eutrofização , Cromatografia Líquida , Espectrometria de Massas em Tandem
2.
Oncologist ; 25(5): e816-e832, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32219909

RESUMO

PURPOSE: This article reports on the long-term impact of radiotherapy adapted to stage, histology, and previous resection in a large cohort of patients with intestinal lymphoma (iL) treated with definitive or adjuvant curative-intent radiation therapy (RT) ± chemotherapy (CHOP, MCP, or COP). PATIENTS AND METHODS: In two consecutive prospective study designs, 134 patients with indolent (stage IE-IIE) or aggressive (stage IE-IVE) iL were referred to 61 radiotherapeutic institutions between 1992 and 2003. Patients with indolent iL received extended field (EF) 30 Gy (+10 Gy boost in definitive treatment); patients with aggressive iL received involved field (IF) (EF) 40 Gy by means of stage-, histology-, and operation-adapted radiation fields. RESULTS: The patients had median age 58 years and were predominantly male (2:1). Histology showed aggressive prevalence (1.6:1), stage IE-to-stage IIE ratio of iL 1.04:1, and localized stages-to-advanced stages ratio of aggressive lymphoma 23:1. Median follow-up was in total 11.7 years: 10.0 years in the first study, GIT (GastroIntestinal-Tract) 1992, and 11.8 years in the second study, GIT 1996. Lymphoma involvement was predominantly a single intestinal lesion (82.1%). Decrease of radiation field size from EF to IF in stage I aggressive iL from GIT 1992 to GIT 1996 resulted in a nonsignificant partial reduction of chronic toxicity while maintaining comparable survival rates (5-year overall survival 87.9 vs. 86.7%, 10-year overall survival 77.4 vs. 71.5%) with nonsignificant difference in event-free survival (5-year event-free survival 82.6 vs. 86.7%, 10-year event-free survival 69.7 vs. 71.5%) and lymphoma-specific survival (5-year lymphoma-specific survival 90.1 vs. 91.9%, 10-year lymphoma-specific survival 87.6% vs. 91.9%). Comparative dose calculation of two still available indolent duodenal lymphoma computed tomography scans revealed lower radiation exposure to normal tissues from applying current standard involved site RT (ISRT) 30 Gy in both cases. CONCLUSION: RT adapted to stage, histology, and resection in multimodal treatment of iL, despite partially decreasing field size (EF to IF), achieves excellent local tumor control and survival rates. The use of modern RT technique and target volume with ISRT offers the option of further reduction of normal tissue complication probability. IMPLICATIONS FOR PRACTICE: Although patients with intestinal lymphoma (iL) are heterogeneous according to histology and subtype, they benefit from radiotherapy. Prospective study data from 134 patients with indolent iL (stage IE-IIE) or aggressive iL (stage IE-IVE) show 100% tumor control after definitive or adjuvant curative-intent radiation therapy ± chemotherapy. Radiation treatment was applied between 1992 and 2003. Median follow-up in total was 11.7 years. No radiotherapy-associated death occurred. Relapse developed in 15.7% of the entire cohort; distant failure was more frequent than local (4:1). Normal tissue complication probability can be further improved using modern involved site radiation therapy techniques.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Linfoma não Hodgkin , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Combinada , Seguimentos , Humanos , Linfoma não Hodgkin/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Estudos Prospectivos
3.
J Nat Prod ; 81(11): 2576-2581, 2018 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-30369239

RESUMO

Cyanobufalins A-C (1-3), a new series of cardiotoxic steroids, have been discovered from cyanobacterial blooms in Buckeye Lake and Grand Lake St. Marys in Ohio. Compounds 1-3 contain distinctive structural features, including geminal methyl groups at C-4, a 7,8 double bond, and a C-16 chlorine substituent that distinguish them from plant- or animal-derived congeners. Despite these structural differences, the compounds are qualitatively identical to bufalin in their cytotoxic profiles versus cell lines in tissue culture and cardiac activity, as demonstrated in an impedance-based cellular assay conducted with IPSC-derived cardiomyocytes. Cyanobufalins are nonselectively toxic to human cells in the single-digit nanomolar range and show stimulation of contractility in cardiomyocytes at sub-nanomolar concentrations. The estimated combined concentration of 1-3 in the environment is in the same nanomolar range, and consequently more precise quantitative analyses are recommended along with more detailed cardiotoxicity studies. This is the first time that cardioactive steroid toxins have been found associated with microorganisms in an aquatic environment. Several factors point to a microbial biosynthetic origin for the cyanobufalins.


Assuntos
Cianobactérias/metabolismo , Proliferação Nociva de Algas , Coração/efeitos dos fármacos , Toxinas Biológicas/toxicidade , Humanos
4.
J Nat Prod ; 81(6): 1368-1375, 2018 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-29847132

RESUMO

Four new microcystin congeners are described including the first three examples of microcystins containing the rare doubly homologated tyrosine residue 2-amino-5-(4-hydroxyphenyl)pentanoic acid (Ahppa) (1-4). Large-scale harvesting and biomass processing allowed the isolation of substantial quantities of these compounds, thus enabling complete structure determination by NMR as well as cytotoxicity evaluation against selected cancer cell lines. The new Ahppa-toxins all incorporate Ahppa residues at the 2-position, and one of these also has a second Ahppa at position 4. The two most lipophilic Ahppa-containing microcystins showed 10-fold greater cytotoxic potency against human tumor cell lines (A549 and HCT-116) compared to microcystin-LR (5). The presence of an Ahppa residue in microcystin congeners is difficult to ascertain by MS methods alone, due to the lack of characteristic fragment ions derived from the doubly homologated side chain. Owing to their unexpected cytotoxic potency, the potential impact of the compounds on human health should be further evaluated.


Assuntos
Citotoxinas/química , Citotoxinas/farmacologia , Microcistinas/química , Microcistinas/farmacologia , Microcystis/química , Tirosina/química , Células A549 , Linhagem Celular Tumoral , Células HCT116 , Humanos , Ácidos Pentanoicos/química , Ácidos Pentanoicos/farmacologia
5.
Tetrahedron Lett ; 58(43): 4066-4068, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-32189813

RESUMO

Mass spectrometry-guided isolation of the lipophilic extract of Trichodesmium bloom material led to the isolation and structure characterization of a new thiazole-containing di-chlorinated polyketide (1). The structure of 1 was deduced using 1D and 2D NMR analysis, high-resolution mass spectrometry analysis and complementary spectroscopic procedures. Trichothiazole A possesses interesting structural features, such as a terminal alkyne, two vinyl chlorides and a 2,4-disubstituted thiazole. Trichothiazole A showed moderate cytotoxicity to Neuro-2A cells (EC50: 13.3 ± 1.1 µM).

6.
Dis Aquat Organ ; 123(2): 87-99, 2017 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-28262632

RESUMO

Fish die-offs are important signals in tropical marine ecosystems. In 2010, a mass mortality of pufferfish in Hawaii (USA) was dominated by Arothron hispidus showing aberrant neurological behaviors. Using pathology, toxinology, and field surveys, we implicated a series of novel, polar, marine toxins as a likely cause of this mass mortality. Our findings are striking in that (1) a marine toxin was associated with a kill of a fish species that is itself toxic; (2) we provide a plausible mechanism to explain clinical signs of affected fish; and (3) this epizootic likely depleted puffer populations. Whilst our data are compelling, we did not synthesize the toxin de novo, and we were unable to categorically prove that the polar toxins caused mortality or that they were metabolites of an undefined parent compound. However, our approach does provide a template for marine fish kill investigations associated with marine toxins and inherent limitations of existing methods. Our study also highlights the need for more rapid and cost-effective tools to identify new marine toxins, particularly small, highly polar molecules.


Assuntos
Doenças dos Peixes/induzido quimicamente , Toxinas Marinhas/toxicidade , Tetraodontiformes , Animais , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/mortalidade , Doenças dos Peixes/patologia , Havaí/epidemiologia , Toxinas Marinhas/química
7.
Mar Drugs ; 15(1)2017 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-28067831

RESUMO

In an effort to isolate and characterize bioactive secondary metabolites from Trichodesmium thiebautii blooms, collected cyanobacteria biomass was subjected to bioassay-guided extraction and fractionation using the human colon cancer cell line HCT-116, resulting in the isolation and subsequent structure characterization of a linear polyketide trichophycin A (1). The planar structure of 1 was completed using 1D and 2D NMR spectroscopy and high-resolution electrospray ionization mass spectrometry (HRESIMS). Trichophycin A was moderately toxic against the murine neuroblastoma cell line Neuro-2A (EC50: 6.5 µM) and HCT-116 cells (EC50: 11.7 µM). Trichophycin A was significantly more cytotoxic than the previously isolated polyketides trichotoxin A and trichotoxin B. These cytotoxicity observations suggest that toxicity may be related to the polyol character of these polyketide compounds.


Assuntos
Cianobactérias/química , Policetídeos/química , Trichodesmium/química , Animais , Peptídeos Catiônicos Antimicrobianos , Linhagem Celular Tumoral , Células HCT116 , Humanos , Espectroscopia de Ressonância Magnética/métodos , Camundongos , Neuroblastoma/tratamento farmacológico , Peptídeos/química , Peptídeos/farmacologia , Policetídeos/farmacologia , Espectrometria de Massas por Ionização por Electrospray/métodos
8.
Mar Drugs ; 15(7)2017 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-28665343

RESUMO

Bioassay-guided isolation of the lipophilic extract of Trichodesmium thiebautii bloom material led to the purification and structure characterization of two new hybrid polyketide-non-ribosomal peptide (PKS-NRPS) macrocyclic compounds, tricholides A and B (1 and 2). A third macrocyclic compound, unnarmicin D (3), was identified as a new depsipeptide in the unnarmicin family, given its structural similarity to the existing compounds in this group. The planar structures of 1-3 were determined using 1D and 2D NMR spectra and complementary spectroscopic and spectrometric procedures. The absolute configurations of the amino acid components of 1-3 were determined via acid hydrolysis, derivitization with Marfey's reagent and HPLC-UV comparison to authentic amino acid standards. The absolute configuration of the 3-hydroxydodecanoic acid moiety in 3 was determined using a modified Mosher's esterification procedure on a linear derivative of tricharmicin (4) and additionally by a comparison of 13C NMR shifts of 3 to known depsipeptides with ß-hydroxy acid subunits. Tricholide B (2) showed moderate cytotoxicity to Neuro-2A murine neuroblastoma cells (EC50: 14.5 ± 6.2 µM).


Assuntos
Antineoplásicos/isolamento & purificação , Peptídeos Cíclicos , Peptídeos/isolamento & purificação , Trichodesmium/química , Animais , Peptídeos Catiônicos Antimicrobianos , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Neuroblastoma/tratamento farmacológico , Peptídeos/química , Peptídeos/farmacologia
9.
Am J Hematol ; 91(9): 923-30, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27312795

RESUMO

Primary mediastinal B-cell lymphoma (PMBL) is an entity of B-cell lymphoma distinct from the other molecular subtypes of diffuse large B-cell lymphoma (DLBCL). We investigated the prevalence, specificity, and clinical relevance of mutations of XPO1, which encodes a member of the karyopherin-ß nuclear transporters, in a large cohort of PMBL. PMBL cases defined histologically or by gene expression profiling (GEP) were sequenced and the XPO1 mutational status was correlated to genetic and clinical characteristics. The XPO1 mutational status was also assessed in DLBCL, Hodgkin lymphoma (HL) and mediastinal gray-zone lymphoma (MGZL).The biological impact of the mutation on Selective Inhibitor of Nuclear Export (SINE) compounds (KPT-185/330) sensitivity was investigated in vitro. XPO1 mutations were present in 28/117 (24%) PMBL cases and in 5/19 (26%) HL cases but absent/rare in MGZL (0/20) or DLBCL (3/197). A higher prevalence (50%) of the recurrent codon 571 variant (p.E571K) was observed in GEP-defined PMBL and was associated with shorter PFS. Age, International Prognostic Index and bulky mass were similar in XPO1 mutant and wild-type cases. KPT-185 induced a dose-dependent decrease in cell proliferation and increased cell-death in PMBL cell lines harboring wild type or XPO1 E571K mutant alleles. Experiments in transfected U2OS cells further confirmed that the XPO1 E571K mutation does not have a drastic impact on KPT-330 binding. To conclude the XPO1 E571K mutation represents a genetic hallmark of the PMBL subtype and serves as a new relevant PMBL biomarker. SINE compounds appear active for both mutated and wild-type protein. Am. J. Hematol. 91:923-930, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Carioferinas/genética , Linfoma de Células B/genética , Mutação , Receptores Citoplasmáticos e Nucleares/genética , Acrilatos/farmacologia , Adolescente , Adulto , Idoso , Biomarcadores , Linhagem Celular Tumoral , Feminino , Perfilação da Expressão Gênica , Doença de Hodgkin/genética , Humanos , Hidrazinas/farmacologia , Carioferinas/antagonistas & inibidores , Carioferinas/fisiologia , Linfoma de Células B/mortalidade , Linfoma de Células B/patologia , Masculino , Neoplasias do Mediastino/genética , Neoplasias do Mediastino/mortalidade , Pessoa de Meia-Idade , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/fisiologia , Análise de Sequência de DNA , Triazóis/farmacologia , Adulto Jovem , Proteína Exportina 1
10.
Tetrahedron Lett ; 57(52): 5864-5867, 2016 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-32153305

RESUMO

NMR-guided fractionation of the lipophilic extract of Trichodesmium thiebautii filaments led to the isolation of a phenyl-containing chlorinated polyketide (1) and an alkyne-containing analogue (2). Comparison of spectroscopic and spectrometric data of 1 with the data of the previously reported trichotoxin, strongly suggested that these metabolites were identical and supports a structural revision of trichotoxin and its designation as trichotoxin A. In addition, we report the isolation and characterization of the alkyne-containing analogue trichotoxin B (2). Absolute configuration of 1 and 2 is proposed based on spectroscopic comparison to a close structural analog.

11.
BMC Cancer ; 15: 220, 2015 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-25885064

RESUMO

BACKGROUND: Up to 50% of penile squamous cell carcinomas (pSCC) develop in the context of high-risk human papillomavirus (HR-HPV) infection. Most of these tumours have been reported to show basaloid differentiation and overexpression of tumour suppressor protein p16(INK4a). Whether HPV-triggered carcinogenesis in pSCC has an impact on tumour aggressiveness, however, is still subject to research. METHODS: In tissue specimens from 58 patients with surgically treated pSCC between 1995 and 2012, we performed p16(INK4a) immunohistochemistry and DNA extraction followed by HPV subtyping using a PCR-based approach. The results were correlated with histopathological and clinical parameters. RESULTS: 90.4% of tumours were of conventional (keratinizing) subtype. HR-HPV DNA was detected in 29.3%, and a variety of p16(INK4a) staining patterns was observed in 58.6% of samples regardless of histologic subtype. Sensitivity of basaloid subtype to predict HR-HPV positivity was poor (11.8%). In contrast, sensitivity and specificity of p16(INK4a) staining to predict presence of HR-HPV DNA was 100% and 57%, respectively. By focussing on those samples with intense nuclear staining pattern for p16(INK4a), specificity could be improved to 83%. Both expression of p16(INK4a) and presence of HR-HPV DNA, but not histologic grade, were inversely associated with pSCC tumour invasion (p = 0.01, p = 0.03, and p = 0.71). However, none of these correlated with nodal involvement or distant metastasis. In contrast to pathological tumour stage, the HR-HPV status, histologic grade, and p16(INK4a) positivity failed to predict cancer-specific survival. CONCLUSIONS: Our results confirm intense nuclear positivity for p16(INK4a), rather than histologic subtype, as a good predictor for presence of HR-HPV DNA in pSCC. HR-HPV / p16(INK4a) positivity, independent of histological tumour grade, indicates a less aggressive local behaviour; however, its value as an independent prognostic indicator remains to be determined. Since local invasion can be judged without p16(INK4a)/HPV-detection on microscopic evaluation, our study argues against routine testing in the setting of pSCC.


Assuntos
Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/patologia , Inibidor p16 de Quinase Dependente de Ciclina/genética , Papillomaviridae/genética , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/virologia , Neoplasias Penianas/etiologia , Neoplasias Penianas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/mortalidade , DNA Viral , Expressão Gênica , Genótipo , Humanos , Imuno-Histoquímica , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Neoplasias Penianas/mortalidade
12.
Mar Drugs ; 13(1): 65-75, 2014 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-25548974

RESUMO

Aquatic microbes produce diverse secondary metabolites with interesting biological activities. Cytotoxic metabolites have the potential to become lead compounds or drugs for cancer treatment. Many cytotoxic compounds, however, show undesirable toxicity at higher concentrations. Such undesirable activity may be reduced or eliminated by using lower doses of the cytotoxic compound in combination with another compound that modulates its activity. Here, we have examined the cytotoxicity of four microbial metabolites [ethyl N-(2-phenethyl) carbamate (NP-1), Euglenophycin, Anabaenopeptin, and Glycolipid 652] using three in vitro cell lines [human breast cancer cells (MCF-7), mouse neuroblastoma cells (N2a), and rat pituitary epithelial cells (GH4C1)]. The compounds showed variable cytotoxicity, with Euglenophycin displaying specificity for N2a cells. We have also examined the modulatory power of NP-1 on the cytotoxicity of the other three compounds and found that at a permissible concentration (125 µg/mL), NP-1 sensitized N2a and MCF-7 cells to Euglenophycin and Glycolipid 652 induced cytotoxicity.


Assuntos
Adjuvantes Farmacêuticos/uso terapêutico , Antineoplásicos/uso terapêutico , Produtos Biológicos/uso terapêutico , Glicolipídeos/uso terapêutico , Animais , Antineoplásicos/administração & dosagem , Produtos Biológicos/administração & dosagem , Produtos Biológicos/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral/efeitos dos fármacos , Glicolipídeos/administração & dosagem , Humanos , Células MCF-7/efeitos dos fármacos , Toxinas Marinhas/administração & dosagem , Toxinas Marinhas/uso terapêutico , Camundongos , Neuroblastoma/tratamento farmacológico , Peptídeos Cíclicos/administração & dosagem , Peptídeos Cíclicos/uso terapêutico , Piperidinas/administração & dosagem , Piperidinas/uso terapêutico , Ratos , Água do Mar/microbiologia , Tiazóis/administração & dosagem , Tiazóis/uso terapêutico
13.
Cell Death Dis ; 15(5): 323, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724507

RESUMO

Richter's syndrome (RS) is the transformation of chronic lymphocytic leukemia (CLL) into a high-grade B-cell malignancy. Molecular and functional studies have pointed out that CLL cells are close to the apoptotic threshold and dependent on BCL-2 for survival. However, it remains undefined how evasion from apoptosis evolves during disease transformation. Here, we employed functional and static approaches to compare the regulation of mitochondrial apoptosis in CLL and RS. BH3 profiling of 17 CLL and 9 RS samples demonstrated that RS cells had reduced apoptotic priming and lower BCL-2 dependence than CLL cells. While a subset of RS was dependent on alternative anti-apoptotic proteins and was sensitive to specific BH3 mimetics, other RS cases harbored no specific anti-apoptotic addiction. Transcriptomics of paired CLL/RS samples revealed downregulation of pro-apoptotic sensitizers during disease transformation. Albeit expressed, effector and activator members were less likely to colocalize with mitochondria in RS compared to CLL. Electron microscopy highlighted reduced cristae width in RS mitochondria, a condition further promoting apoptosis resistance. Collectively, our data suggest that RS cells evolve multiple mechanisms that lower the apoptotic priming and shift the anti-apoptotic dependencies away from BCL-2, making direct targeting of mitochondrial apoptosis more challenging after disease transformation.


Assuntos
Apoptose , Leucemia Linfocítica Crônica de Células B , Mitocôndrias , Proteínas Proto-Oncogênicas c-bcl-2 , Humanos , Leucemia Linfocítica Crônica de Células B/patologia , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Mitocôndrias/metabolismo , Masculino , Feminino , Pessoa de Meia-Idade
14.
Environ Sci Technol ; 47(6): 2728-36, 2013 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-23402624

RESUMO

A major impediment to understanding the impact of environmental stress, including toxins and other pollutants, on organisms, is that organisms are rarely challenged by one or a few stressors in natural systems. Thus, linking laboratory experiments that are limited by practical considerations to a few stressors and a few levels of these stressors to real world conditions is constrained. In addition, while the existence of complex interactions among stressors can be identified by current statistical methods, these methods do not provide a means to construct mathematical models of these interactions. In this paper, we offer a two-step process by which complex interactions of stressors on biological systems can be modeled in an experimental design that is within the limits of practicality. We begin with the notion that environment conditions circumscribe an n-dimensional hyperspace within which biological processes or end points are embedded. We then randomly sample this hyperspace to establish experimental conditions that span the range of the relevant parameters and conduct the experiment(s) based upon these selected conditions. Models of the complex interactions of the parameters are then extracted using machine learning tools, specifically artificial neural networks. This approach can rapidly generate highly accurate models of biological responses to complex interactions among environmentally relevant toxins, identify critical subspaces where nonlinear responses exist, and provide an expedient means of designing traditional experiments to test the impact of complex mixtures on biological responses. Further, this can be accomplished with an astonishingly small sample size.


Assuntos
Inteligência Artificial , Meio Ambiente , Poluentes Ambientais/toxicidade , Modelos Biológicos , Animais , Linhagem Celular , Camundongos
15.
Environ Sci Technol ; 45(17): 7503-9, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21740025

RESUMO

Trichodesmium is a suspected toxin-producing nonheterocystous cyanobacteria ubiquitous in tropical, subtropical, and temperate seas. The genus is known for its ability to fix nitrogen and form massive blooms. In oligotrophic seas, it can dominate the biomass and be a major component of oceanic primary production and global nitrogen cycling. Numerous reports suggest Trichodesmium-derived toxins are a cause of death of fish, crabs, and bivalves. Laboratory studies have demonstrated neurotoxic effects in T. thiebautii cell extracts and field reports suggest respiratory distress and contact dermatitis of humans at collection sites. However, Trichodesmium toxins have not been identified and characterized. Here, we report the extraction of a lipophilic toxin from field-collected T. thiebautii using a purification method of several chromatographic techniques, nuclear magnetic resonance (NMR), mass spectroscopy (MS), and Fourier transformed-infrared spectroscopy (FT-IR). Trichotoxin has a molecular formula of C(20)H(27)ClO and a mass of 318 m/z and possesses cytotoxic activity against GH(4)C(1) rat pituitary and Neuro-2a mouse neuroblastoma cells. A detection method using liquid chromatography/mass spectrometry (LC/MS) was developed. This compound is the first reported cytotoxic natural product isolated and fully characterized from a Trichodesmium species.


Assuntos
Cloro/química , Cianobactérias/química , Peptídeos/isolamento & purificação , Água do Mar/microbiologia , Animais , Peptídeos Catiônicos Antimicrobianos , Humanos , Estrutura Molecular , Peptídeos/química , Peptídeos/toxicidade
16.
Biochem Biophys Res Commun ; 403(3-4): 275-81, 2010 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-21073864

RESUMO

Compounds with anti-angiogenic properties are useful in combating cancer by preventing new blood vessel formation to support the tumor. In this report we introduce a rapid method for screening potential anti-angiogenic compounds in a model system that stimulates the production of secondary defense chemicals in plants. This methodology identified an inducible vascular factor (IVF3), which was found to be inhibitory in all of the model systems tested. Thyme plants were exposed to highly vascular mint plants and the methanol extracts were analyzed by reverse phase HPLC. The thyme compounds induced by the invading mint tissue, and not present in the thyme plants grown alone, were tested in a vertical plate assay measuring root length as a quantitative assay for drug sensitivity. The HPLC-purified extract, referred to as IVF3, reduced the growth of root vascular tissue compared to the control and vehicle control, and 50% as well as known angiogenesis inhibitors, VEGF receptor tyrosine kinase inhibitor and amiloride hydrochloride. Extracted compounds that were effective inhibitors of plant roots were assayed in Madin Darby canine kidney epithelial cells (MDCK) for toxicity, and in human umbilical vein endothelial cells (HUVEC) for their effect on migration. IVF3 was effective at limiting HUVEC migration in VEGF-stimulated cultures. In vivo video capture of intersegmental vessel circulation between 48 and 72 h post fertilization in the developing vasculature of zebrafish embryos showed IVF3 also significantly reduced ISV functional circulation. This report demonstrates the anti-angiogenic effects of IVF3 extract in endothelial cells and in an intact vertebrate model for angiogenesis.


Assuntos
Inibidores da Angiogênese/isolamento & purificação , Inibidores da Angiogênese/farmacologia , Células Endoteliais/efeitos dos fármacos , Thymus (Planta)/química , Veias Umbilicais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/farmacologia , Inibidores da Angiogênese/química , Animais , Movimento Celular , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Cães , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Humanos , Metanol/química , Neovascularização Fisiológica/efeitos dos fármacos , Veias Umbilicais/citologia
17.
Microb Ecol ; 59(4): 646-57, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20309538

RESUMO

Vibrio coralliilyticus is a global marine pathogen that has been found to cause disease in several marine organisms, including corals. This study is the first report of the isolation of V. coralliilyticus from a diseased Caribbean octocoral, Pseudopterogorgia americana. Five sister phylotypes were positively identified using 16S rRNA gene sequencing, recA probes specific for V. coralliilyticus, and rep-PCR fingerprinting. The antimicrobial resistance was compared between pathogenic strains of V. coralliilyticus and the Caribbean strains. First, the antimicrobial resistance of V. coralliilyticus-type strain ATCC BAA-450 was determined using an agar-overlay antimicrobial bioassay at 24 degrees C and 27 degrees C, temperatures which are relevant to its known temperature-dependent virulence. From 108 distinct bacteria isolated from P. americana, 12 inhibited the V. coralliilyticus-type strain at 24 degrees C and five at 27 degrees C. Next, the phenotypic comparison of two Caribbean phylotypes and three V. coralliilyticus reference strains against a subset of 30 bacteria demonstrated a similar resistance trend. At both temperatures, the reference strains were inhibited by three bacteria isolates, while the Caribbean strains were inhibited by four to nine bacteria. Additionally, V. coralliilyticus-type strain ATCC BAA-450 and one of the Caribbean strains were inhibited by a higher number of bacteria at 24 degrees C compared with 27 degrees C. Together, these results highlight that V. coralliilyticus strains have antimicrobial resistance to the majority of coral-associated bacteria tested, which may be temperature-dependent in some strains. Furthermore, all V. coralliilyticus strains tested showed multi-drug resistance to a range of 11-16 (out of 26) commercial antibiotics. This study establishes V. coralliilyticus in association with a Caribbean octocoral and demonstrates its resistance to the antimicrobial activity of coral-associated bacteria and to commercial antibiotics.


Assuntos
Antozoários/microbiologia , Farmacorresistência Bacteriana , Vibrio/genética , Animais , Antibacterianos/farmacologia , Região do Caribe , Impressões Digitais de DNA , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/genética , Vibrio/efeitos dos fármacos , Vibrio/isolamento & purificação
18.
Respiration ; 78(2): 203-8, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19246874

RESUMO

BACKGROUND: Specimens from transbronchial lung biopsies lack sufficient quality due to crush artifact and are generally too small for diagnosis of diffuse lung diseases. Flexible cryoprobes have been shown to be useful in therapeutic bronchoscopy. We introduce a novel technique for obtaining lung biopsies bronchoscopically, using a flexible cryoprobe. OBJECTIVES: The purpose of this study was to show the feasibility of using a cryoprobe to obtain lung biopsies during flexible bronchoscopy. METHODS: Forty-one patients with radiographic signs of diffuse lung disease were selected for transbronchial biopsy. During flexible bronchoscopy, conventional transbronchial biopsies using forceps were done first. Then a flexible cryoprobe was introduced into the selected bronchus under fluoroscopic guidance. Once brought into position, the probe was cooled and then retracted with the frozen lung tissue being attached on the probe's tip. The tissue was processed for histology. After establishing a diagnosis, the specimen area was measured using a digital morphometry system. RESULTS: We evaluated the biopsy samples of 41 patients. The mean specimen area was 5.82 mm(2) (0.58-20.88 mm(2)) taken by forceps compared to 15.11 mm(2) obtained using the cryoprobe (2.15-54.15 mm(2), p < 0.01). Two patients had a pneumothorax which resolved with tube thoracostomy. Biopsy-associated bleeding did not require any intervention. Transbronchial cryobiopsy contributed in a substantial number of cases to a definitive diagnosis. CONCLUSIONS: Transbronchial cryobiopsy is a novel technique which allows to obtain large biopsy samples of lung parenchyma that exceed the size and quality of forceps biopsy samples. Prospective trials are needed to compare this technique with surgical lung biopsy for diagnosis of diffuse lung diseases.


Assuntos
Biópsia/instrumentação , Broncoscopia/métodos , Criocirurgia , Pulmão/patologia , Biópsia/métodos , Humanos , Pneumopatias/diagnóstico , Estudos Retrospectivos
19.
Int Biodeterior Biodegradation ; 63(4): 529-532, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23874076

RESUMO

Methods used to deter biofouling of underwater structures and marine vessels present a serious environmental issue and are both problematic and costly for government and commercial marine vessels worldwide. Current antifouling methods include compounds that are toxic to aquatic wildlife and marine ecosystems. Dihydrooroidin (DHO) was shown to completely inhibit Halomonas pacifica biofilms at 100 µM in a static biofilm inhibition assay giving precedence for the inhibition of other marine-biofilm-forming organisms. Herein we present DHO as an effective paint-based, non-cytotoxic, antifouling agent against marine biofouling processes in a marine mesocosm.

20.
Food Chem Toxicol ; 123: 9-15, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30300722

RESUMO

A mini-survey of 29 different foods produced by 21 different Indian manufacturers was conducted for the presence of aflatoxins B1, B2, G1 and G2, aflatoxin M1 and deoxynivalenol. The products were purchased from local markets in Kolkata, India and commonly used in the complementary feeding of infants and toddlers in India. Using a previously established direct competitive enzyme-linked immunoassay for this analysis we show that 100% of the samples contained aflatoxin M1 at levels exceeding the recommended European Union levels of 25 ng kg-1 by more than an order of magnitude. Also, several (66%) of them contained detectable concentrations of deoxynivalenol with two samples (6.9%) exceeding European Union guidelines for baby food products (200 µg kg-1) and 51.7% samples with DON levels that can lead to dietary intake higher than 1  µg kg-1 recommended by the joint FAO/WHO expert committee on food additives. None of the samples contained aflatoxins B1, B2, G1 and G2. The results, therefore, suggest that complementary feeding can put Indian infants and toddlers at risk of simultaneous exposures to deoxynivalenol and aflatoxin M1 and warrant an urgent in-depth research to track, increase surveillance and reduce mycotoxin contamination of baby foods manufactured in India.


Assuntos
Aflatoxina M1/análise , Contaminação de Alimentos/análise , Tricotecenos/análise , Pré-Escolar , Feminino , Humanos , Índia , Lactente , Alimentos Infantis/análise , Fenômenos Fisiológicos da Nutrição do Lactente , Masculino , Inquéritos e Questionários
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