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1.
Forensic Sci Int ; 354: 111908, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38096750

RESUMO

INTRODUCTION AND OBJECTIVES: To investigate the epidemiological characteristics, clinic-pathological findings and recent use of substances of abuse and prescribed drugs in sexual activity-related sudden death (SArSD). METHODS: Multicenter population-based study on forensic autopsies conducted in 27 provinces of Spain over 12 years (2010-2021). RESULTS: Out of 18046 autopsied natural deaths, 64 cases (0.35 %) of SArSD were investigated (87 % males). Women were younger than males (50.5 ± 13.4 years vs 37.2 ± 14.2; p = 0.017). Sudden cardiac deaths (SCD) accounted for 87 % of cases. Ischemic heart disease was the predominant pathology (58 %), mainly affecting men ≥ 36 years of age. Cerebral haemorrhage (8 %) and asthma (5 %) were the leading non-cardiac causes. In young adults, SADS (36 %) and asthma (27 %) were the main causes The disease responsible of SCD was diagnosed in life in 7 subjects. In 64 % there were cardiovascular risk factors, mainly obesity. Toxicological analysis detected illicit drugs (23 %), mainly cocaine, medications for erectile dysfunction (9 %), and ethanol ≥ 0.5 g/L (8 %). Deaths occurred usually in the context of heterosexual intercourse and during or immediately after sexual activity. The most common location was at home (63 %). In 12 men the sexual partner was a sex worker. CONCLUSIONS: SArSD has a low incidence in the general population affecting middle-aged males during intercourse with a heterosexual partner. It is of cardiovascular origin, mainly due to ischemic heart disease that frequently remained silent during life. There is a frequent association with obesity, use of cocaine (and, to a lesser extent, medications for erectile dysfunction) and performing unconventional sexual practices. Forensic investigation is useful for developing prevention strategies.


Assuntos
Asma , Cocaína , Disfunção Erétil , Isquemia Miocárdica , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Humanos , Feminino , Disfunção Erétil/complicações , Comportamento Sexual , Morte Súbita Cardíaca/epidemiologia , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/patologia , Autopsia , Obesidade/complicações , Causas de Morte
2.
Bioresour Technol ; 359: 127490, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35724909

RESUMO

The low tolerance of marine microalgae to ammonium and hyposalinity limits their use in urban wastewater (UWW) treatments. In this study, using the marine microalga Amphidinium carterae, it is demonstrated for the first time that this obstacle can be overcome by introducing a zeolite-based adsorption step to obtain a tolerable UWW stream. The maximum ammonium adsorption capacities measured in the natural zeolite used are among the highest reported. The microalga grows satisfactorily in mixtures of zeolite-treated UWW and seawater at a wide range of proportions, both with and without adjusting the salinity, as long as the ammonium concentration is below the threshold tolerated by the microalgae (6.3 mg L-1). A proof of concept performed in 10-L bubble column photobioreactors with different culture strategies, including medium recycling, showed an enhanced biomass yield relative to a control with no UWW. No noticeable effect was observed on the production of specialty metabolites.


Assuntos
Compostos de Amônio , Microalgas , Zeolitas , Adsorção , Compostos de Amônio/metabolismo , Biomassa , Microalgas/metabolismo , Fotobiorreatores , Águas Residuárias , Zeolitas/metabolismo
3.
Rev Esp Quimioter ; 35(1): 50-62, 2022 Feb.
Artigo em Espanhol | MEDLINE | ID: mdl-34859658

RESUMO

OBJECTIVE: To analyse and compare 30-day mortality prognostic power of several biomarkers (C-reactive protein, procalcitonin, lactate and suPAR) in patients seen in emergency departments (ED) due to infections. Secondly, if these could improve the accuracy of systemic inflammatory response syndrome (SIRS) and quick Sepsis-related Organ Failure Assessment (qSOFA). METHODS: A prospective, observational and analytical study was carried out on patients who were treated in an ED of one of the eight participating hospitals. An assessment was made of 32 independent variables that could influence mortality at 30 days. They covered epidemiological, comorbidity, functional, clinical and analytical factors. RESULTS: The study included 347 consecutive patients, 54 (15.6%) of whom died within 30 days of visiting the ED. SUPAR has got the best biomarker area under the curve (AUC)-ROC to predict mortality at 30 days of 0.836 (95% CI: 0.765-0.907; P <.001) with a cut-off > 10 ng/mL who had a sensitivity of 70% and a specificity of 86%. The score qSOFA ≥ 2 had AUC-ROC of 0.707 (95% CI: 0.621-0.793; P < .001) with sensitivity of 53% and a specificity of 89%. The mixed model (suPAR > 10 ng/mL plus qSOFA ≥ 2) has improved the AUC-ROC to 0.853 [95% CI: 0.790-0.916; P < .001] with the best prognostic performance: sensitivity of 39% and a specificity of 97% with a negative predictive value of 90%. CONCLUSIONS: suPAR showed better performance for 30-day mortality prognostic power from several biomarkers in the patients seen in ED due to infections. Score qSOFA has better performance that SRIS and the mixed model (qSOFA ≥ 2 plus suPAR > 10 ng/mL) increased the ability of qSOFA.


Assuntos
Receptores de Ativador de Plasminogênio Tipo Uroquinase , Sepse , Biomarcadores , Serviço Hospitalar de Emergência , Humanos , Prognóstico , Estudos Prospectivos , Curva ROC
4.
Geobiology ; 16(1): 49-61, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29076282

RESUMO

Cyanobacteria have long been thought to induce the formation of Ca-carbonates as secondary by-products of their metabolic activity, by shifting the chemical composition of their extracellular environment to conditions favoring mineral precipitation. Some cyanobacterial species forming Ca-carbonates intracellularly were recently discovered. However, the environmental conditions under which this intracellular biomineralization process can occur and the impact of cyanobacterial species forming Ca-carbonates intracellularly on extracellular carbonatogenesis are not known. Here, we show that these cyanobacteria can form Ca-carbonates intracellularly while growing in extracellular solutions undersaturated with respect to all Ca-carbonate phases, that is, conditions thermodynamically unfavorable to mineral precipitation. This shows that intracellular Ca-carbonate biomineralization is an active process; that is, it costs energy provided by the cells. The cost of energy may be due to the active accumulation of Ca intracellularly. Moreover, unlike cyanobacterial strains that have been usually considered before by studies on Ca-carbonate biomineralization, cyanobacteria forming intracellular carbonates may slow down or hamper extracellular carbonatogenesis, by decreasing the saturation index of their extracellular solution following the buffering of the concentration of extracellular calcium to low levels.


Assuntos
Carbonato de Cálcio/metabolismo , Cyanothece/metabolismo , Cálcio/metabolismo , Técnicas de Cultura , Cyanothece/crescimento & desenvolvimento
5.
Transplant Proc ; 46(6): 2096-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25131115

RESUMO

Lesions produced in the graft mucosa due to harvesting, storage, and implantation must be graduated to assess the subsequent protocolized biopsy specimens. The aim is to identify type and intensity of graft mucosal lesions observed immediately after implantation. Congestion, hemorrhage, microthrombi, neutrophilic infiltrates, shortening of villi, epithelial detachment, erosion, and crypt loss were separately evaluated by two pathologists in mucosal biopsy specimens from 13 grafts. Each change was assessed as normal, mild, moderate, or severe and by splintering the summation of points a global score was designed. Cold ischemia time was registered. Correlation between the pathologists' evaluations and between final preservation injury degree and cold ischemia time was determined using the "index of correlation rho (ρ)" (Spearman's test). The same changes were assessed in 19 biopsy specimens from day 2 to day 6 (3.6 ± 1.1) to determine their evolution. Congestion was found in 7 biopsy specimens, microthrombi in 2, hemorrhage in 4, neutrophils in 6, villous atrophy in 8, epithelial detachment in 9, erosions in 2 and/or crypt loss in 2. The maximum degree of preservation injury was expressed as intense congestion and hemorrhage associated with epithelial detachment and villous atrophy. The global preservation score was grade 3 in 2 cases, grade 2 in 5, grade 1 in 2, and grade 0 in 4. There was positive correlation (ρ = 0.915) in the evaluation between pathologists (P < .01), total agreement in 9 biopsy specimens, and partial agreement (only 1 point disagreement) in 4. Mean cold ischemia time was 327 ± 101 min. (135-480). There was positive correlation (ρ = 0.694) between preservation score and cold ischemia time (P < .01). In the follow-up biopsy procedures, histological injury decreased by at least one grade in every case. Additionally, karyorrhexis was observed in 3 grafts and very occasional apoptosis in 2 others. This scale achieves good reproducibility and allows graduate preservation injury in intestinal transplantation.


Assuntos
Mucosa Intestinal/patologia , Intestino Delgado/patologia , Intestino Delgado/transplante , Preservação de Órgãos/efeitos adversos , Transplantes/patologia , Biópsia , Isquemia Fria/efeitos adversos , Humanos , Mucosa Intestinal/lesões , Preservação de Órgãos/métodos , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Transplantes/lesões
6.
Transplant Proc ; 46(6): 2099-101, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25131116

RESUMO

C4d deposits are predictive of humoral rejection in kidney and heart transplantation. The aim of this study was to identify C4d deposit patterns in intestinal mucosa of the grafts on biopsy specimens obtained immediately after implantation and to detect if it could be a valuable tool to predict humoral or acute rejection. A second objective was to search for a statistically significant relationship between positive C4d deposition and other collected variables. Thirteen immediately post-transplantation mucosal graft biopsy specimens, formalin fixed, underwent immunohistochemical stain for C4d deposits. Diffuse intense staining of capillary endothelium was considered positive and absent, focal or weak stains as negative. Preservation injury grade and cold ischemia times were registered for each case. Donor-specific preformed antibodies were detected by complement dependent cytotoxicity serologic technique (crossmatching). Another 19 endoscopic follow-up biopsy specimens from days 2 to 6 were also evaluated. Statistical studies were made using the index of correlation ρ (Spearman's test). Diffuse intense C4d deposits were observed in 2 grafts, focal and weak in 5, and completely negative in 6. The mean cold ischemia time was 327 ± 101 minutes. Two cases showed diffuse positive deposits, 1 had a positive crossmatch and the cold ischemia time was 360 minutes whereas the other had not preformed antibodies and its cold ischemia time was 475 minutes. Humoral or acute rejection was not observed in follow-up mucosal biopsy specimens. There was no statistically significant relationship between the C4d deposition, cold ischemia time, crossmatching results, and preservation injury degree. In conclusion, C4d deposition was not a helpful tool for diagnosis of humoral rejection and prediction of acute rejection during the early post-transplantation period.


Assuntos
Complemento C4b/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Intestinos/transplante , Transplantes/metabolismo , Transplantes/patologia , Biópsia , Tipagem e Reações Cruzadas Sanguíneas , Estudos de Coortes , Isquemia Fria , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/metabolismo , Rejeição de Enxerto/patologia , Humanos , Intestinos/patologia , Valor Preditivo dos Testes , Fatores de Risco
7.
Geobiology ; 11(1): 55-71, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23205581

RESUMO

Lipid biomarkers and their stable carbon isotopic composition, as well as 16S rRNA gene sequences, were investigated in sediment cores from active seepage zones in the Sea of Marmara (Turkey) located on the active North Anatolian Fault, to assess processes associated with methane turnover by indigenous microbial communities. Diagnostic (13) C-depleted archaeal lipids of anaerobic methane oxidizers were only found in one core from the South of Çinarcik Basin and consist mainly of archaeol, sn-2 hydroxyarchaeol and various unsaturated pentamethylicosenes. Concurrently, abundant fatty acids (FAs) and a substantial amount of monoalkylglycerolethers (MAGEs), assigned to sulphate-reducing bacteria, were detected with strong (13) C-depletions. Both microbial lipids and their δ(13) C values suggest that anaerobic oxidation of methane with sulphate reduction (AOM/SR) occurs, specially in the 10- to 12-cm depth interval. Lipid biomarker results accompanied by 16S rRNA-based microbial diversity analyses showed that ANME-2 (ANME-2a and -2c) archaea and Desulfosarcina/Desulfococcus and Desulfobulbus deltaproteobacterial clades are the major AOM assemblages, which indicate a shallow AOM community at high methane flux. Apart from the typical AOM lipid biomarker pattern, a (13) C-depleted diunsaturated hydrocarbon, identified as 7,14-tricosadiene, occurred in the inferred maximum AOM interval at 10-12 cm depth. Its isotopic fingerprint implies that its microbial precursor occurs in close association with the AOM communities. Interestingly, the presence of 7,14-tricosadiene coincides with the presence of the so-far uncultured bacterial Candidate Division JS1, often detected in AOM areas. We propose the hypothesis that the JS1 bacterial group could be the potential source of (13) C-depleted tricosadiene. Future testing of this hypothesis is essential to fully determine the role of this bacterial group in AOM.


Assuntos
Archaea/genética , Archaea/metabolismo , Bactérias/genética , Bactérias/metabolismo , Metabolismo dos Lipídeos , Metano/metabolismo , Archaea/classificação , Archaea/isolamento & purificação , Bactérias/classificação , Bactérias/isolamento & purificação , Biodiversidade , Biomarcadores/análise , Clonagem Molecular , DNA Arqueal/genética , DNA Arqueal/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Mar Mediterrâneo , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Análise de Sequência de RNA , Homologia de Sequência , Turquia
8.
Artigo em Inglês | LILACS | ID: lil-621567

RESUMO

An analytical method based on capillary electrophoresis (CE) with a partially aqueous electrolyte system was developed to enable the free fatty acids of Brazil nut oil to be identified in cosmetic formulations. In this study, a gel cream formulation was developed and its oil phase was extracted with a mixture of chloroform-methanol-water (1:2:0.8 v/v/v). The chloroform layer was saponified with a methanolic solution of NaOH (0.5 mol L-1) at 75-80 °C for 25 minutes. Experiments were carried out on a Beckman PACE/MDQ CE system (Fullerton, CA, USA) equipped with an on-column, diode-array detection system set at 254 nm and at 25ºC. The electrolyte consisted of 12.5 mmol L-1 sodium tetraborate buffer pH 7.0, 12.5 mmol L-1 polyoxyethylene 23-lauryl ether, 7.5 mmol L-1 sodium dodecylbenzenesulfonate (used as chromophore for indirect UV detection) and acetonitrile (35% v/v). The proposed method allowed the separation and identification of the fatty acids of Brazil nut oil in a cosmetic gel cream, as well as enabling possible interference by the oily phase components in the formulation to be identified.


Um método de análise por eletroforese capilar com sistema de eletrólito parcialmente aquoso foi desenvolvido para identificar os ácidos graxos livres do óleo de Castanha do Brasil em formulações cosméticas. No presente trabalho foi desenvolvida uma formulação cosmética (gel creme) cuja fase oleosa foi extraída com uma mistura de clorofórmio-metanol-água (1:2:0.8 v/v/v). A camada de clorofórmio, foi saponificada com solução de NaOH em metanol (0,5 mol L-1) a 75-80 °C durante 25 minutos. Os experimentos foram realizados em sistema de eletroforese capilar Beckman PACE/MDQ (Fullerton, CA, USA), com detecção de arranjo de diodos a 254 nm e a 25 ºC. O eletrólito utilizado foi 12,5 mmol L-1 de tetraborato de sódio tampão a pH 7,0, 12,5 mmol L-1 de éter de polioxietileno 23-lauril, 7,5 mmol L-1 de dodecilbenzenosulfonato de sódio (utilizado como agente cromóforo para detecção UV indireta) e acetonitrila (35% v/v). O método proposto permitiu a separação e a identificação dos ácidos graxos do óleo de Castanha do Brasil em formulações cosméticas, bem como possibilitou a identificação de interferências presentes na fase oleosa da formulação.


Assuntos
Cosméticos , Eletroforese Capilar , Ácidos Graxos
9.
Epidemiol Infect ; 136(11): 1552-5, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18205974

RESUMO

Nine cases of brucellosis were identified in the city of Elche (Comunidad Valenciana, Spain) in two families of Moroccan immigrants. All of the patients had drunk unpasteurized raw milk from goats. Brucella melitensis biovar 3 was identified in clinical specimens. Preventive measures for brucellosis should be implemented among immigrant populations in Spain.


Assuntos
Brucella melitensis/isolamento & purificação , Brucelose/epidemiologia , Surtos de Doenças , Leite/microbiologia , Adolescente , Adulto , Animais , Brucella melitensis/classificação , Emigrantes e Imigrantes , Feminino , Cabras , Humanos , Masculino , Espanha/epidemiologia
11.
J Pharm Biomed Anal ; 39(3-4): 764-8, 2005 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-15936163

RESUMO

A high performance liquid chromatographic (HPLC) and a ultraviolet derivative spectrophotometric (UVDS) methods were developed and validated for the quantitative determination of hydroquinone (HQ) in gels and creams containing this compound as a unique active principle. Validation parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD) and limit of quantitation (LOQ) were determined. HPLC was carried out by reversed phase technique on a RP-18 column with a mobile phase composed of methanol and water (20:80, v/v). The linearity in the range of 6.0-30.0 microg/mL present a correlation coefficient (r) of 0.9999, calculated by least square method. The LOD and LOQ were 0.08 and 0.26 microg/mL, respectively. Based on the preliminary spectrophotometric profile of HQ, a signal at 302.0 nm of the first derivative spectrum (1D302.0) was found adequate for validation. The linearity between signal 1D302.0 and concentration of HQ in the range of 10.0-26.0 microg/mL in sulfuric acid (0.1N) present a correlation coefficient (r) of 0.9999. The LOD and LOQ were 0.14 and 0.46 microg/mL, respectively. Statistical analysis by t- and F-tests, showed no significant difference at 95% confidence level between the two proposed methods.


Assuntos
Química Farmacêutica/métodos , Cromatografia Líquida de Alta Pressão/métodos , Indústria Farmacêutica/métodos , Hidroquinonas/análise , Espectrofotometria Ultravioleta/métodos , Calibragem , Géis , Metanol/análise , Análise de Regressão , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de Tempo , Raios Ultravioleta , Água/química
12.
Neuroepidemiology ; 24(4): 221-9, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15832060

RESUMO

We tested the feasibility of a fully automated brain MRI voxel count technique--automated labeling pathway (ALP)--in a sample of 15 demented and 13 cognitively normal women (age 75-85 years) participating to the Cardiovascular Health Study (CHS). We hypothesized that ALP would replicate well-established findings of the anatomical correlates of dementia. In particular, we hypothesized that ALP volumetric measures would: (1) significantly differ between cognitively normal and demented women in those brain areas that are established markers for diagnosis of dementia (temporal and medial temporal lobes, hippocampus, amygdala and parahippocampus) but not in other brain areas (e.g., occipital lobe, visual cortex, motor cortex) and (2) correlate with visual ratings of brain disease which have been previously collected as part of the CHS. ALP required minimal operator intervention (input of brain images and verification of misalignments) and employed computer time of about 1 h per brain. ALP detected significant focal volumetric differences in the limbic system (p values between groups for hippocampus and parahippocampus: 0.002 and 0.005, respectively), temporal lobe (p < 0.0001) and caudate (p = 0.009), but not in other brain areas (e.g. occipital lobe, visual or motor cortex). Furthermore, ALP measures of medial temporal lobe atrophy strongly correlated with CHS visual ratings of ventricular enlargement (r(2) = 0.6, p = 0.002 for medial temporal lobe). In conclusion, ALP-detected focal brain atrophy was strongly associated with dementia. Because of its fully automated design, ALP technique is an ideal candidate to assess whether volumetric measures of specific areas can discriminate dementia better than currently available measures of global brain atrophy in large epidemiological studies.


Assuntos
Encéfalo/patologia , Demência/patologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética/métodos , Idoso , Idoso de 80 Anos ou mais , Escolaridade , Estudos de Viabilidade , Feminino , Nível de Saúde , Humanos , Tamanho do Órgão , Reprodutibilidade dos Testes
13.
Rev. diagn. biol ; 52(4): 280-284, oct. 2003. tab, graf
Artigo em Es | IBECS | ID: ibc-35253

RESUMO

Los objetivos planteados en el presente estudio son, evaluar el grado de control glucémico a largo plazo de pacientes diabéticos de nuestra área sanitaria en función de la glicohemoglobina (HbA1c), según los criterios definidos por el European NIDDM Policy Group, así como evaluar una de las complicaciones crónicas más frecuentes de los diabéticos, la afectación renal, mediante la cuantificación de microalbuminuria (MA) como marcador precoz para predecir el desarrollo de nefropatía diabética en dichos pacientes, y de esta forma permitir que se inicien tratamientos destinados a revertir o enlentecer su progresión hacia la enfermedad renal. Los resultados que se presentan se obtuvieron del análisis de HbA1c de sangre procedentes de 6374 pacientes diabéticos, y del análisis de las muestras de orina procedentes de 2961 pacientes diabéticos. De los pacientes a los que se les midió la HbA1c, 1803 (28,2 por ciento) presentaban resultados óptimos (8 por ciento). De los pacientes a los que se les midió la microalbuminuria, 1997 (67,4 por ciento) presentaban valores de microalbuminuria negativas (01,9 mg/dl), 520 (17,5 por ciento) presentaban valores altos (2,0-5,7 mg/dl) y 444 (14,9 por ciento) presentaban valores muy altos de microalbuminuria (>5,7 mg/dl). La frecuencia de microalbuminuria (32,4 por ciento) encontrada en nuestro estudio es similar a la hallada en otros estudios, por lo que habrá que incidir en este grupo de población, con una atención integral e individual de dichos pacientes en los que la determinación de microalbuminuria tiene interés pronóstico en los diabéticos tipo 1 en los que anuncia una nefropatía diabética. También permite evaluar un riesgo de naturaleza cardiovascular. En los diabéticos tipo 2, la microalbuminuria predice una mortalidad prematura, estando asociada a factores de riesgo cardiovasculares clásicos, no específicos de la diabetes, aunque frecuentemente, más precoces y más graves como hipertensión arterial y dislipemias (AU)


Assuntos
Feminino , Masculino , Humanos , Albuminúria/etiologia , Diabetes Mellitus/metabolismo , Hemoglobinas Glicadas/análise , Nefropatias Diabéticas/diagnóstico , Hipertensão/diagnóstico , Hiperlipidemias/diagnóstico
14.
FEMS Microbiol Ecol ; 36(2-3): 193-202, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11451524

RESUMO

To contribute to the understanding of deep-sea planktonic communities, we explored the prokaryotic diversity of a 3000 m deep site at the Antarctic Polar Front using molecular methods. Bacterial 16S rDNA-amplified sequences corresponded to the as yet uncultivated groups SAR11, within the alpha-Proteobacteria, and SAR324, within the delta-Proteobacteria, as well as to the gamma-Proteobacteria, Cytophagales, Planctomyces, Gram-positives, and the group of environmental sequences SAR406. Among them, gamma-proteobacterial sequences were the most abundant and diverse. Within Archaea, and using six different primer sets for 16S rDNA amplification, only euryarchaeotal sequences were retrieved. Most of them clustered with the Thermoplasma-related marine groups II and III, but some corresponded to a recently described group of marine sequences emerging at the base of haloarchaea. Our data suggest that gamma-Proteobacteria and Euryarchaeota may be dominant elements in terms of genetic diversity of the two prokaryotic domains in this deep-sea pelagic area.

15.
Nature ; 409(6820): 603-7, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11214316

RESUMO

Phylogenetic information from ribosomal RNA genes directly amplified from the environment changed our view of the biosphere, revealing an extraordinary diversity of previously undetected prokaryotic lineages. Using ribosomal RNA genes from marine picoplankton, several new groups of bacteria and archaea have been identified, some of which are abundant. Little is known, however, about the diversity of the smallest planktonic eukaryotes, and available information in general concerns the phytoplankton of the euphotic region. Here we recover eukaryotes in the size fraction 0.2-5 microm from the aphotic zone (250-3,000 m deep) in the Antarctic polar front. The most diverse and relatively abundant were two new groups of alveolate sequences, related to dinoflagellates that are found at all studied depths. These may be important components of the microbial community in the deep ocean. Their phylogenetic position suggests a radiation early in the evolution of alveolates.


Assuntos
Variação Genética , Plâncton/genética , Animais , Regiões Antárticas , Células Eucarióticas , Dados de Sequência Molecular , Oceanos e Mares , Filogenia , Plâncton/classificação , RNA Ribossômico 18S/genética
16.
Environ Microbiol ; 3(1): 72-8, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11225725

RESUMO

During our study of the 16S rRNA gene sequence-based archaeal diversity of a deep-sea site located at a 3,000 m depth at the Antarctic Polar Front, we detected several phylotypes ascribed to already known Group II and III Euryarchaeota, and a cluster of distinct sequences that branched off at the base of haloarchaea. The position of this lineage (marine Group IV) was very robust using distance (neighbour-joining) and maximum-likelihood methods. Subsequently, we designed specific primers for the detection of this archaeal group in other marine environments using polymerase chain reaction amplification and sequence comparison. Group IV archaea were found in the Antarctic area (across a gradient from the Southern ocean to the South Atlantic), and also in North Atlantic and Mediterranean waters. In all oceanic locations, Group IV archaea were never detected in surface waters, but were vertically distributed in the deepest part of the water column.


Assuntos
Archaea/isolamento & purificação , Água do Mar/microbiologia , Regiões Antárticas , Archaea/classificação , Archaea/crescimento & desenvolvimento , Oceano Atlântico , DNA Bacteriano/análise , DNA Ribossômico/análise , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/análise , Análise de Sequência de DNA
17.
Int J Syst Evol Microbiol ; 51(Pt 6): 2211-2219, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11760964

RESUMO

The phylum Euglenozoa consists of three distinct groups: the euglenoids, diplonemids and kinetoplastids. The phylogenetic position of the diplonemids within this phylum remains unsettled, since both morphological and molecular data produce weak and contradictory results. It is shown here that taxonomic sampling, G+C content bias, mutational saturation and differences of evolutionary rate among lineages are major factors affecting the topology of the small-subunit rRNA euglenozoan tree. When these problems are minimized by using a larger diplonemid sampling (including a sequence of environmental origin) and correcting for G+C bias (by using both paralinear distances or an unbiased dataset), a diplonemids+euglenoids sisterhood is retrieved. Bootstrap support for this relationship is still moderate, but it is retrieved by all analysis methods, overcoming previously reported disagreements. In addition, the inclusion of a large number of euglenoid sequences in the analysis improves some phylogenetic relationships within this group. Some problematic taxa, such as the species Khawkinea quartana, are now placed with high bootstrap support and monophyly is found for two interesting groups (the photosynthetic genera Eutreptia+Eutreptiella and the loricate genera Strombomonas+Trachelomonas), although with weak statistical support.


Assuntos
Eucariotos/classificação , Eucariotos/genética , Filogenia , Animais , Composição de Bases , DNA Ribossômico/genética , Euglênidos/genética , Evolução Molecular , Dados de Sequência Molecular , RNA Ribossômico/genética , Água do Mar/parasitologia , Análise de Sequência de DNA
18.
J Bacteriol ; 182(17): 4998-5000, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10940047

RESUMO

We present evidence that, in contrast to plasmids from other hyperthermophilic archaea, which are in the relaxed to positively supercoiled state, plasmid pGS5 (2.8 kb) from Archaeoglobus profundus is negatively supercoiled. This might be due to the presence of a gyrase introducing negative supercoils, since gyrase genes are present in the genome of its close relative A. fulgidus, and suggests that gyrase activity predominates over reverse gyrase whenever the two topoisomerases coexist in cells.


Assuntos
Archaeoglobus/genética , DNA Arqueal , DNA Super-Helicoidal , Plasmídeos , Archaeoglobus/crescimento & desenvolvimento
19.
Bioessays ; 22(8): 738-46, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10918304

RESUMO

During heat shock and cold shock, plasmid DNA supercoiling changes transiently both in mesophilic bacteria and in hyperthermophilic archaea, despite a different overall topology (negative supercoiling versus relaxation to positive supercoiling). Transient changes in DNA supercoiling might be essential to generate the stress response, but they could also be a consequence of the physical effects of temperature on cellular components. Indeed, both appear intertwined. Comparison of the mechanisms acting in the two biological systems suggests that the dependence on temperature of the activity of different DNA topoisomerases, as well as of protein binding, are key factors for the control of DNA topology during stress, which may in turn be relevant for the expression of stress-induced genes.


Assuntos
DNA Super-Helicoidal/química , Temperatura Baixa , DNA Arqueal/química , DNA Bacteriano/química , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/química , Temperatura Alta , Conformação de Ácido Nucleico , Plasmídeos/química , Sulfolobus/química
20.
Science ; 288(5474): 2212-5, 2000 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-10864870

RESUMO

Despite a rapid increase in the amount of available archaeal sequence information, little is known about the duplication of genetic material in the third domain of life. We identified a single origin of bidirectional replication in Pyrococcus abyssi by means of in silico analyses of cumulative oligomer skew and the identification of an early replicating chromosomal segment. The replication origin in three Pyrococcus species was found to be highly conserved, and several eukaryotic-like DNA replication genes were clustered around it. As in Bacteria, the chromosomal region containing the replication terminus was a hot spot of genome shuffling. Thus, although bacterial and archaeal replication proteins differ profoundly, they are used to replicate chromosomes in a similar manner in both prokaryotic domains.


Assuntos
Cromossomos de Archaea/metabolismo , Replicação do DNA/genética , DNA Arqueal/biossíntese , Genoma Arqueal , Pyrococcus/genética , Pyrococcus/metabolismo , Proteínas de Saccharomyces cerevisiae , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Bactérias/genética , Bactérias/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Sequência Conservada , DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células Eucarióticas/metabolismo , Evolução Molecular , Genes Arqueais , Complexo de Reconhecimento de Origem , Puromicina/farmacologia , Origem de Replicação
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