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1.
Mar Pollut Bull ; 198: 115856, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38061146

RESUMO

As deposit feeders contribute to bioremediation and nutrient recycling in sediments, positively impacting water and sediment quality, holothurians are candidate organisms for multitrophic aquaculture. This study aimed to investigate the potential of Holothuria poli to reduce the environmental footprint of fish farms through a benthocosm experiment. The experimental setup included four benthocosms with holothurians(H+) and four without (H-). The 58-day experiment included two phases: constant organic enrichment and recovery. In order to simulate the organic enrichment sediment conditions under a typical fish farm, a mixture of fish feces and fish feed pellets was added. Results showed that holothurians effectively reduced organic matter and H2S and increased redox, RPD depth and sediment oxygenation, thereby preventing anoxic conditions. Also, during the recovery phase, holothurians facilitated rapid sediment recovery, while the sediments without holothurians remained organic-enriched until the end of the experiment. The study emphasizes the significance of holothurians in mitigating the impacts of aquaculture on sediment conditions and so promoting environmental sustainability.


Assuntos
Aquicultura , Pepinos-do-Mar , Animais , Aquicultura/métodos , Pesqueiros , Peixes , Oxirredução , Sedimentos Geológicos , Monitoramento Ambiental/métodos
2.
Biology (Basel) ; 12(12)2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38132346

RESUMO

Ocean acidification (OA) and ocean warming (OW) are potential obstacles to the survival and growth of marine organisms, particularly those that rely on calcification. This study investigated the single and joint effects of OA and OW on sea cucumber Apostichopus japonicus larvae raised under combinations of two temperatures (19 °C or 22 °C) and two pCO2 levels (400 or 1000 µatm) that reflect the current and end-of-21st-century projected ocean scenarios. The investigation focused on assessing larval development and identifying differences in gene expression patterns at four crucial embryo-larval stages (blastula, gastrula, auricularia, and doliolaria) of sea cucumbers, using RNA-seq. Results showed the detrimental effect of OA on the early development and body growth of A. japonicus larvae and a reduction in the expression of genes associated with biomineralization, skeletogenesis, and ion homeostasis. This effect was particularly pronounced during the doliolaria stage, indicating the presence of bottlenecks in larval development at this transition phase between the larval and megalopa stages in response to OA. OW accelerated the larval development across four stages of A. japonicus, especially at the blastula and doliolaria stages, but resulted in a widespread upregulation of genes related to heat shock proteins, antioxidant defense, and immune response. Significantly, the negative effects of elevated pCO2 on the developmental process of larvae appeared to be mitigated when accompanied by increased temperatures at the expense of reduced immune resilience and increased system fragility. These findings suggest that alterations in gene expression within the larvae of A. japonicus provide a mechanism to adapt to stressors arising from a rapidly changing oceanic environment.

3.
Pathogens ; 12(11)2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-38003742

RESUMO

Klebsiella pneumoniae is one of the leading causes of nosocomial infections. It has been estimated that nosocomial infection by Klebsiella pneumoniae comprises 3-8% of all nosocomial infections. Klebsiella pneumoniae bloodstream infections (BSIs) occur worldwide with varying mortality. Resistant strains, like those producing extended-spectrum beta-lactamases (ESBL) and carbapenemases, are becoming increasingly common, especially in hospital settings, posing therapeutic challenges. In this article, we aimed to study the epidemiology and risk factors of BSIs due to resistant Klebsiella pneumoniae strains in the period 1 January 2014-31 December 2018 at the Nicosia General Hospital, the largest tertiary hospital in Cyprus. Data on demographics, co-morbidities, prior hospitalization, prior intensive care unit (ICU) admission, previous antimicrobial use, nosocomial acquisition of the infection, the presence of a prosthetic device or surgery, and the primary site of infection were retrospectively recorded. Associations between the detection of ESBL Klebsiella pneumoniae BSIs and factors/covariates were examined using logistic regression. This study involved 175 patients with BSI caused by Klebsiella pneumoniae. Of these, 61 BSIs were caused by ESBL strains, 101 by non-ESBL, and 13 by carbapenem-resistant (CR) strains. In univariable analyses, age, sex, heart disease, antimicrobial use during current admission, previous hospitalization (ward or ICU), and primary BSI were associated with the presence of an ESBL strain. Antibiotic use during current admission and heart disease remained statistically significantly associated with ESBL Klebsiella pneumoniae BSI in multivariable models. Antibiotic use during current admission, respiratory infection, and a recent history of surgery were more prevalent among CR Klebsiella pneumoniae BSI patients than among non-CR Klebsiella pneumoniae BSI patients. Our study showed that recent antimicrobial use and heart disease were associated with BSI due to ESBL-producing Klebsiella pneumoniae. This finding could inform clinical practice in hospital settings.

4.
Mar Pollut Bull ; 194(Pt A): 115418, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37611338

RESUMO

The implementation of sustainable system designs in aquaculture comprises the biological treatment of pollutants. In order to test the potential of Holothuria (Roweothuria) poli as a candidate for bioremediation of aquaculture wastes, the effect of this species on the benthic microbial activity was studied. Two experimental treatments, with and without holothuroids, were allocated in two benthocosms, each one containing four replicate tanks with undisturbed sediment and a volume of water above it. It was anticipated that H. poli could affect the overall assimilative capacity of the aquaculture effluent system either through the consumption of particulate organic matter or through the stimulation of benthic microbial metabolism. Indeed, the results indicated that the microbial activity related to the mineralization of the N and C was significantly different between the treatments verifying our hypothesis that deposit-feeders that move above or inside the sediment matrix can accelerate the depletion of organic matter through bioturbation.


Assuntos
Aquicultura , Poluentes Ambientais , Biodegradação Ambiental , Material Particulado , Água
5.
Pathogens ; 9(11)2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33238551

RESUMO

BACKGROUND: Outbreaks of acute hepatitis A (AHA) have recently been reported in Europe among men who have sex with men (MSM). The aim of this work was to evaluate, for the first time, trends in the reported cases of AHA in Cyprus over the last seven years. METHODS: We retrospectively studied all people reported with AHA in Cyprus between January 2013 and December 2019. Demographic data, type of transmission, vaccination status for HAV, laboratory and clinical data were analyzed. RESULTS: The asnalysis involved 33 AHA cases (age 32.7 ± 17.4 years, 78.8% males). An increase in AHA reports was observed between July 2017 and June 2018 when more than a third (n = 13) of the cases of the period 2013-2019 were reported. The reporting rate of AHA doubled from 0.52 cases per 100,000 population (before July 2017) to 1.12 cases per 100,000 population (July 2017-June 2018). The male/female (M/F) ratio increased from one in 2013 to eight in 2018. CONCLUSION: An increase in AHA reports occurred in Cyprus between July 2017 and June 2018. Many cases with AHA in that period were MSM. Enhanced surveillance and timely public health interventions, like vaccination and awareness promotion, are important for preventing future outbreaks.

6.
Mar Pollut Bull ; 153: 110997, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32275546

RESUMO

The present study aimed to compare anthropogenic impacts in three Mediterranean ports (Cagliari-Italy, Heraklion-Greece, El-Kantatoui-Tunisia) employing benthic macrofaunal indices, used in the context of the European Water Framework Directive. Sampling stations were selected within ports according to sector usage categorization and sampled over three seasons. Benthic indices calculated include M-AMBI, BENTIX, BQI and BQI_Family. Comparisons were made between the indices values and ecological status (ES) of each station within and between ports. Overall, few statistically significant differences were observed across different seasons or different stations with the same usage within or across ports. The ES of sampling stations in the leisure/fishing and passenger/cargo ships sectors was mostly "good" or "moderate", while the shipyard sector had "poor" ES. The results suggest that the indices used were suitable for assessing the ES of Mediterranean ports, led to comparable results even across different countries and contribute to the adaptation of specific port monitoring guidelines.


Assuntos
Ecossistema , Monitoramento Ambiental , Animais , Grécia , Invertebrados , Itália , Estações do Ano , Tunísia
7.
Mar Environ Res ; 150: 104752, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31326679

RESUMO

The effects of the abrupt input of high quantities of dissolved inorganic nitrogen and phosphorus on prokaryotic and eukaryotic microbial plankton were investigated in an attempt to simulate the nutrient disturbances caused by eutrophication and climate change. Two nutrient levels were created through the addition of different quantities of dissolved nutrients in a mesocosm experiment. During the developed blooms, compositional differences were found within bacteria and microbial eukaryotes, and communities progressed towards species of faster metabolisms. Regarding the different nutrient concentrations, different microbial species were associated with each nutrient treatment and community changes spanned from the phylum to the operational taxonomic unit (OTU) level. Network analyses revealed important differences in the biotic connections developed: more competitive relationships were established in the more intense nutrient disturbance and networks of contrasting complexity were formed around species of different ecological strategies. This work highlights that sudden disturbances in water column chemistry lead to the development of entirely different microbial food webs with distinct ecological characteristics.


Assuntos
Eucariotos , Microbiota , Código de Barras de DNA Taxonômico , Eutrofização , Nitrogênio , Nutrientes , Fósforo
8.
Brain Inj ; 33(9): 1257-1261, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31293186

RESUMO

Background and aims: Pre-hospital delay is a crucial factor that determines the eligibility for intravenous thrombolysis in patients with acute ischemic stroke. We aimed to evaluate the time to presentation at the emergency department (ED) and the factors that affect this time. Patients and methods: We prospectively studied 682 patients who were admitted with acute ischemic stroke (43.3% men, age 79.9 ± 6.6 years). Results: The median time to presentation at the ED was 2.1 h (range 0.15 to 168 h); 68.8% of the patients arrived within 4.5 h and 56.5% arrived within 3 h from the onset of symptoms. Independent predictors of presentation within 4.5 h were the use of emergency medical services (EMS) for transportation to the hospital (OR 2.61, 95% CI 1.38-4.94, p = .003), family history of cardiovascular disease (CVD)(OR 4.0 0,95%CI 1.61-12.23, p = .006) and the absence of history of smoking (OR 2.49, 95% CI 1.13-5.42, p = .021). Independent predictors of presentation within 3 h were the use of EMS for transportation to the hospital (OR 6.24, 95% CI 2.52-16.63, p = .0001), family history of CVD (OR 3.07, 95% CI 1.14-9.43, p = .03), and a moderately severe stroke at admission (OR vs. minor stroke 0.38, 95% CI 0.16-0.87, p = .02). Conclusions: A considerable proportion of patients with acute ischemic stroke arrives at the ED after the 4.5-h threshold for performing intravenous thrombolysis. Non-smokers, patients with a family history of CVD, with moderately severe stroke and those who use the EMS are more likely to arrive on time.


Assuntos
Isquemia Encefálica/terapia , Serviços Médicos de Emergência/estatística & dados numéricos , Acidente Vascular Cerebral/terapia , Tempo para o Tratamento , Idoso , Idoso de 80 Anos ou mais , Serviço Hospitalar de Emergência , Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco
9.
Mar Environ Res ; 140: 10-17, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29843909

RESUMO

Marine habitat assessment using indicator species through Species Distribution Modeling (SDM) was investigated. The bivalves: Corbula gibba and Flexopecten hyalinus were the indicator species characterizing disturbed and undisturbed areas respectively in terms of chlorophyll a concentration in Greece. The habitat suitability maps of these species reflected the overall ecological status of the area. The C. gibba model successfully predicted the occurrence of this species in areas with increased physical disturbance driven by chlorophyll a concentration, whereas the habitat map for F. hyalinus showed an increased probability of occurrence in chlorophyll-poor areas, affected mainly by salinity. We advocate the use of C. gibba as a proxy for eutrophication and the incorporation of this species in monitoring studies through SDM methods. For the Mediterranean Sea we suggest the use of F. hyalinus in SDM as an indicator of environmental stability and a possible forecasting tool for salinity fluctuations.


Assuntos
Ecossistema , Monitoramento Ambiental/métodos , Biodiversidade , Conservação dos Recursos Naturais , Ecologia , Eutrofização , Grécia , Mar Mediterrâneo , Salinidade
10.
Sci Total Environ ; 605-606: 637-645, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28672252

RESUMO

A mesocosm experiment was performed to study benthic-pelagic coupling under a eutrophication gradient. Nine mesocosms were deployed in the facilities of the Hellenic Center for Marine Research in Crete, in the Eastern Mediterranean. The mesocosms were 4m deep, containing 1.5m3 of coastal water and, at the bottom, they included 85l of undisturbed sediment, collected from a semi-impacted area in the port of Heraklion, Crete. A eutrophication gradient was created by adding nutrients in the water column (Low and High) and the experiment lasted 58days. Water column and sediment environmental variables were measured at regular intervals. The results indicate that sedimentation caused by eutrophication in the water column affected sediment geochemical variables but in most cases a time lag was observed between the trophic status of the water column and the response of the sediment. Additionally, in the High eutrophication treatment, several fluctuations were observed and the system did not recover within the experimental duration, as opposed to the Low treatment which showed fewer fluctuations and signs of recovery.

11.
Cardiovasc Revasc Med ; 18(4): 245-249, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28214141

RESUMO

OBJECTIVES: We sought to assess the feasibility and safety of same-day discharge (SDD) after complex percutaneous coronary intervention (PCI) using a forearm approach. BACKGROUND: SDD has been shown to be safe after elective, low-risk PCI. However, the feasibility and safety of SDD in more complex patients and lesions has received limited study. METHODS: We retrospectively reviewed 1190 elective PCIs that were performed between January 2013 and December 2015 at the Red Cross General Hospital. RESULTS: Of the 1190 PCIs, 166 (13.9%) were complex (bifurcations, vein and arterial grafts, unprotected left main, last remaining vessel, chronic total occlusions, or with utilization of rotational atherectomy or hemodynamic support). As compared with non-complex cases, complex cases were associated with older age, male gender, higher prevalence of diabetes mellitus and prior coronary artery bypass graft surgery, lower prevalence of smoking, higher utilization of femoral access and 7F guiding catheters, higher contrast utilization and fluoroscopy dose, longer fluoroscopy time, more stents per lesion, more frequent single vessel treatment and non-complete revascularization, and treatment with ticagrelor and bivalirudin. Among the patients who underwent complex PCI (n=166), twenty eight (16.9%) were discharged the same day. SDD after complex PCI was associated with younger age and more frequent use of forearm access. The 30-day incidence of major adverse cardiac events after complex PCI was 0% vs 3.6% (p=0.59) in patients with SDD vs. overnight hospitalization. CONCLUSIONS: SDD is feasible and safe in selected patients undergoing elective complex PCI using the forearm approach.


Assuntos
Doença da Artéria Coronariana/terapia , Antebraço/irrigação sanguínea , Longevidade , Alta do Paciente , Intervenção Coronária Percutânea/métodos , Idoso , Idoso de 80 Anos ou mais , Doença da Artéria Coronariana/diagnóstico , Estudos de Viabilidade , Feminino , Grécia , Hospitais Gerais , Humanos , Masculino , Pessoa de Meia-Idade , Segurança do Paciente , Intervenção Coronária Percutânea/efeitos adversos , Sistema de Registros , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
12.
Metabolism ; 67: 99-105, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28081783

RESUMO

BACKGROUND AND AIMS: Stress hyperglycemia is frequent in patients with acute ischemic stroke. However, it is unclear whether stress hyperglycemia only reflects stroke severity or if it is directly associated with adverse outcome. We aimed to evaluate the prognostic significance of stress hyperglycemia in acute ischemic stroke. METHODS: We prospectively studied 790 consecutive patients who were admitted with acute ischemic stroke (41.0% males, age 79.4±6.8years). The severity of stroke was assessed at admission with the National Institutes of Health Stroke Scale (NIHSS). Stress hyperglycemia was defined as fasting serum glucose levels at the second day after admission ≥126mg/dl in patients without type 2 diabetes mellitus (T2DM). The outcome was assessed with adverse outcome rates at discharge (modified Rankin scale between 2 and 6) and with in-hospital mortality. RESULTS: In the total study population, 8.6% had stress hyperglycemia. Patients with stress hyperglycemia had more severe stroke. Independent predictors of adverse outcome at discharge were age, prior ischemic stroke and NIHSS at admission whereas treatment with statins prior to stroke was associated with favorable outcome. When the NIHSS was removed from the multivariate model, independent predictors of adverse outcome were age, heart rate at admission, prior ischemic stroke, log-triglyceride (TG) levels and stress hyperglycemia, whereas treatment with statins prior to stroke was associated with favorable outcome. Independent predictors of in-hospital mortality were atrial fibrillation (AF), diastolic blood pressure (DBP), serum log-TG levels and NIHSS at admission. When the NIHSS was removed from the multivariate model, independent predictors of in-hospital mortality were age, AF, DBP, log-TG levels and stress hyperglycemia. CONCLUSION: Stress hyperglycemia does not appear to be directly associated with the outcome of acute ischemic stroke. However, given that patients with stress hyperglycemia had higher prevalence of cardiovascular risk factors than patients with normoglycemia and that glucose tolerance was not evaluated, more studies are needed to validate our findings.


Assuntos
Isquemia Encefálica/sangue , Isquemia Encefálica/terapia , Hiperglicemia/sangue , Acidente Vascular Cerebral/sangue , Acidente Vascular Cerebral/terapia , Idoso , Idoso de 80 Anos ou mais , Glicemia/análise , Isquemia Encefálica/mortalidade , Diabetes Mellitus Tipo 2/sangue , Feminino , Mortalidade Hospitalar , Hospitalização , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Masculino , Prognóstico , Estudos Prospectivos , Estresse Fisiológico , Acidente Vascular Cerebral/mortalidade , Resultado do Tratamento , Triglicerídeos/sangue
13.
Cardiovasc Revasc Med ; 18(4): 241-244, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28089776

RESUMO

OBJECTIVES: The aim of this study is to identify possible predictors for same day discharge (SDD) after percutaneous coronary interventions (PCI). BACKGROUND: Same day discharge after PCI is becoming more and more appealing and patient's selection criteria are being formulated. METHODS: A retrospective analysis was performed in all PCI procedures from January 2013 until December 2015. Patients were discharged the same day (SDD group) or had at least one overnight stay (non-SDD group). The decision of SDD or not was on treating physician discretion. We evaluated predictors of SDD decision by a logistic regression analysis. RESULTS: One thousand one hundred sixty eight procedures were performed from our department during the study period: 308 patients (26.4%) were discharged the same day (SDD group) and the rest 860 procedures (73.6%) had at least one overnight stay (non-SDD group). Multivariate analysis revealed that forearm approach (OR=5.498, CI: 2.067-14.629; p=<0.001), patient's residency proximal to the hospital (OR=4.543, CI: 2.406-8.580; p<0.001), completion of the procedure before 13,00p.m. (OR=3.437, CI: 1.789-0.6.601; p<0.001) and the success of the performed procedure (OR=1.125, CI 1.043-2.135; p=0.044) were positive predictors of SDD, while presentation with non-ST elevation myocardial infarction or unstable angina (OR=0.542, CI: 0.268-0.872; p<0.010) and amount of contrast used (OR=0.910, CI: 0.852-0.969; p<0.030) were negative predictors of SDD. CONCLUSION: In retrospect, both procedural and demographic details play a crucial role in patient selection for same day discharge post coronary percutaneous intervention.


Assuntos
Doença da Artéria Coronariana/terapia , Longevidade , Alta do Paciente , Intervenção Coronária Percutânea , Idoso , Distribuição de Qui-Quadrado , Tomada de Decisão Clínica , Doença da Artéria Coronariana/diagnóstico , Técnicas de Apoio para a Decisão , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Seleção de Pacientes , Intervenção Coronária Percutânea/efeitos adversos , Valor Preditivo dos Testes , Sistema de Registros , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
14.
Eur J Case Rep Intern Med ; 4(5): 000606, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30755946

RESUMO

AIMS: Lemierre syndrome is a life-threating condition characterized by recent oropharyngeal infection, internal jugular vein thrombosis, and anaerobic septicemia. It is usually caused by Fusobacterium necrophorum. METHODS: A young Romanian male presented with fever and rigors, mild tachypnea, hypoxia, sore throat, decayed teeth, and tenderness of the left carotid triangle. Laboratory examination indicated severe sepsis with disseminated intravascular coagulation, acute renal failure, and acute respiratory distress syndrome while the Doppler ultrasonography of the carotids revealed left internal jugular venous thrombosis. The patient was administered piperacillin/tazobactam and vancomycin intravenously, doxycycline orally, and anti-coagulation by enoxaparin based on the diagnosis of Lemierre syndrome. Meanwhile, he was complicated by bilateral diffuse pulmonary cavities and encapsulated pleural effusions and so transcutaneous drainage was performed. The patient was discharged after a month and continued his treatment with oral phenoxypenicillin and doxycycline until full radiographic improvement. He was switched to oral anti-coagulation by vitamin-K antagonists and was referred to a hematologist, a vascular-surgeon, and a dentist. RESULTS: Streptococcus gordonii was isolated from the patient's blood and pleural fluid cultures and serology for Rickettsial spp. IgM was positive. Thrombophilia genetic tests revealed three minor mutations for fibrinogen-455, plasminogen activator inhibitor-1, and methylenetetrahydrofolate reductase. According to the literature, S. gordonii is not usually a causative agent and Rickettsial spp. have as yet not been correlated with Lemierre syndrome. The failure of left jugular vein recanalization shows a possible causative role of the underlying thrombophilic predisposition. DISCUSSION: Because of the syndrome's rarity and the atypical microorganisms isolated in this case, increased awareness is advised for its diagnosis and the underlying mechanisms involved in its genesis. The role of anti-coagulation is debatable. LEARNING POINTS: Very rare condition. Medical practitioners should be vigilant in its diagnosis since septic jugular vein thrombophlebitis could be misdiagnosed as neck lymphadenitis.Duration of antibiotic therapy and additional anticoagulation treatment are still under discussion.Underlying thrombophilia predisposition should be excluded.

15.
Biodivers Data J ; (4): e10071, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27932921

RESUMO

BACKGROUND: The benthic macrofaunal biodiversity of the southeastern Mediterranean is considerably understudied compared to other Mediterranean regions. Monitoring biodiversity in this area is crucial as this region is particularly susceptible to biological invasions and temperature alteration. Historical biodiversity data could provide a useful baseline for monitoring potential changes and provide informarion to support a better understanding of the possible effects of anthropogenic activities on marine benthic communities. NEW INFORMATION: In this study, performed under the LifeWatchGreece Research Infrastructure, we present historical benthic occurrence data obtained from the sampling expedition carried out in 1933 by Adolf Steuer in the coastal area around Alexandria, Egypt, eastern Mediterranean. The occurrences were geo-referenced to more than 170 stations, mostly located in the area of Alexandria, and the nearby coasts and lakes. All records were digitized and species names were cross-checked and taxonomically updated using the World Register of Marine Species. The outcome clearly shows that such initiatives can reveal an unexpected amount of highly valuable biodiversity information for "data-poor" regions.

16.
Sci Rep ; 6: 29286, 2016 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-27404551

RESUMO

Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.


Assuntos
Luz , Fotossíntese , Plâncton/fisiologia , Animais , Processos Autotróficos , Biomassa , Ecossistema , Processos Heterotróficos , Mar Mediterrâneo , Especificidade de Órgãos , Comportamento Predatório
17.
Radiat Prot Dosimetry ; 172(1-3): 230-237, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27344061

RESUMO

High-dose assessments using the conventional dicentric assay are essentially restricted to doses up to 5 Gy and only to lymphocytes that succeed to proceed to first post-exposure mitosis. Since G2-checkpoint activation facilitates DNA damage recognition and arrest of damaged cells, caffeine is used to release G2-blocked lymphocytes overcoming the mitotic index and dicentric yield saturation problems, enabling thus dicentric analysis even at high-dose exposures. Using the fluorescence in situ hybridization technique with telomere and centromere peptide nucleic acid probes, the released lymphocytes, identified as metaphases with decondensed chromosomes following 1.5 h caffeine treatment, show increased yield of dicentrics compared to that obtained in lymphocytes that reach metaphase without G2-checkpoint abrogation by caffeine. Here, a 3-h caffeine/colcemid co-treatment before harvesting at 55 h post-exposure is used so that the dicentric analysis using Giemsa staining is based predominantly on lymphocytes released from the G2-block, increasing thus dicentric yield and enabling construction of a dose-response calibration curve with improved precision of high-dose estimates.


Assuntos
Cafeína/administração & dosagem , Aberrações Cromossômicas/efeitos da radiação , Análise Citogenética/métodos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Linfócitos/efeitos da radiação , Radiometria/métodos , Bioensaio/métodos , Células Cultivadas , Relação Dose-Resposta à Radiação , Pontos de Checagem da Fase G2 do Ciclo Celular/genética , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Humanos , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Artigo em Inglês | MEDLINE | ID: mdl-26520380

RESUMO

The frequency of dicentric chromosomes in human peripheral blood lymphocytes at metaphase is considered as the "gold-standard" method for biological dosimetry and, presently, it is the most widely used for dose assessment. Yet, it needs lymphocyte stimulation and a 2-day culture, failing the requirement of rapid dose estimation, which is a high priority in radiation emergency medicine and triage biodosimetry. In the present work, we assess the applicability of cell fusion mediated premature chromosome condensation (PCC) methodology, which enables the analysis of radiation-induced chromosomal aberrations directly in non-stimulated G0-lymphocytes, without the 2-day culture delay. Despite its advantages, quantification of an exposure by means of the PCC-method is not currently widely used, mainly because Giemsa-staining of interphase G0-lymphocyte chromosomes facilitates the analysis of fragments and rings, but not of dicentrics. To overcome this shortcoming, the PCC-method is combined with fluorescence in situ hybridization (FISH), using simultaneously centromeric/telomeric peptide nucleic acid (PNA)-probes. This new approach enables an accurate analysis of dicentric and centric ring chromosomes, which are formed within 8h post irradiation and will, therefore, be present in the blood sample by the time it arrives for dose estimation. For triage biodosimetry, a dose response curve for up to 10Gy was constructed and compared to that obtained using conventional metaphase analysis with Giemsa or centromeric/telomeric PNA-probes in metaphase. Since FISH is labor intensive, a simple PCC-method scoring Giemsa-stained fragments in excess of 46 was also assessed as an even more rapid approach for triage biodosimetry. First, we studied the rejoining kinetics of fragments and constructed a dose-response curve for 24h repair time. Then, its applicability was assessed for four different doses and compared with the PCC-method using centromeric/telomeric PNA-probes, through the evaluation of speed of analysis and minimum number of cells required for dose estimation and categorization of exposed individuals.


Assuntos
Centrômero/genética , Aberrações Cromossômicas , Linfócitos/efeitos da radiação , Ácidos Nucleicos Peptídicos/genética , Radiometria/métodos , Corantes Azur , Células Cultivadas , Sondas de DNA/genética , Humanos , Hibridização in Situ Fluorescente , Linfócitos/citologia , Fase de Repouso do Ciclo Celular , Telômero/genética , Triagem/métodos
19.
Mar Pollut Bull ; 101(2): 784-93, 2015 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-26478459

RESUMO

Biological and geochemical variables in the water column and sediments were monitored along a transect of a mussel farm located in a transitional environment in Maliakos Gulf, a semi-enclosed gulf in eastern Mediterranean. Analyses of water, sediment and macrofauna samples were used to calculate ecological status indicators in the context of the European Water Framework Directive. The water column ecological status was "Poor" or "Bad" showing little change with distance from the farm, but the ecological status of the benthic communities was found to be "Good," although there were quantitative changes in macrofaunal indices with distance from the farm.


Assuntos
Aquicultura/métodos , Bivalves , Meio Ambiente , Animais , Ecossistema , Monitoramento Ambiental , Mar Mediterrâneo , Qualidade da Água
20.
PLoS One ; 10(10): e0141071, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26496714

RESUMO

A large data set from the Eastern Mediterranean was analyzed to explore the relationship between seawater column variables and benthic community status. Our results showed a strong quantitative link between the seawater column variables (Chlorophyll a and Eutrophication Index) and various indicators describing benthic diversity and community composition. The percentage of benthic opportunistic species increased significantly in the stations with high trophic status of the seawater column and so did the strength of the coupling between values of seawater column and benthic indicators. The Eutrophication Index threshold level of 0.85, separating the "Bad and Poor" from "Moderate to High" conditions could serve as an acceptable critical value above which there is a readily observable change in benthic community composition.


Assuntos
Clorofila/análise , Monitoramento Ambiental , Eutrofização , Sedimentos Geológicos/química , Água do Mar/química , Biodiversidade , Clorofila A , Interpretação Estatística de Dados , Ecossistema , Humanos , Nitrogênio/análise , Fósforo/análise , Poluentes Químicos da Água/análise
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