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1.
Compr Psychiatry ; 122: 152367, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36774803

RESUMO

BACKGROUND: Intermittent Explosive Disorder (IED) is a disorder primarily of aggression, defined by recurrent behavioral outbursts out of proportion to provocations or stressors. IED first appears in childhood and adolescence. This study examines the underlying childhood environment of those with IED, particularly familial and school-related factors. METHODS: Adult participants from a larger study completed diagnostic assessments and a battery of self-report measures. Group assignment was based on the assessment: 1) IED diagnosis; 2) non-IED psychiatric diagnosis; and 3) no significant psychiatric history. Groups were compared on factors of parental demographics, intrafamilial aggression, lifetime syndromal and personality diagnoses, neurodevelopmental and learning difficulties, childhood peer relationships, and juvenile legal issues. RESULTS: Significant patterns emerged specific to IED for not being raised by both parents, greater physical aggression to participant, and greater degree of fighting with peers by age ten. LIMITATIONS: The retrospective, and cross-sectional, nature of the study, which prevent the making of causal inferences, and the basic nature of the questions asked of participants which limit a more nuanced interpretation of the data. A further limitation is bias associated with self-reported responses. CONCLUSIONS: Results suggest the prevalence childhood adversaries may be linked with IED; the childhood environment of those with IED likely is substantially more tumultuous than individuals with or without other psychiatric disorders.


Assuntos
Transtornos Disruptivos, de Controle do Impulso e da Conduta , Adolescente , Adulto , Humanos , Estudos Transversais , Estudos Retrospectivos , Agressão/psicologia , Pais
2.
J Stroke Cerebrovasc Dis ; 31(9): 106665, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35901588

RESUMO

INTRODUCTION: Transient ischaemic attack (TIA) clinics are important for secondary prevention of fatal or disabling stroke. Non-adherence to prescribed medications is an important reason for treatment failure but difficult to diagnose. This study ascertained the utility of a novel biochemical tool in the objective biochemical diagnosis of non-adherence. METHODS: One-hundred consecutive urine samples collected from patients attending the TIA clinic, at a tertiary centre, were analysed for presence or absence of prescribed cardiovascular medications using liquid chromatography-mass spectrometry (LC-MS/MS). Patients were classified as adherent or non-adherent, respectively. Demographic and clinical characteristics were compared between the two cohorts. Univariate regression analyses were performed for individual variables and model fitting was undertaken for significant variables. RESULTS: The mean duration of follow-up from the index event was 31 days [standard deviation (SD): 18.9]. The overall rate of non-adherence for at least one medication was 24%. In univariate analysis, the number of comorbidities [3.4 (SD: 1.9) vs. 2.5 (1.9), P = 0.032] and total number of all prescribed medications [6.0 (3.3) vs 4.4 (2.1), P = 0.032] were higher in the non-adherent group. On multivariate analysis, the total number of medications prescribed correlated with increased non-adherence (odds ratio: 1.27, 95% Confidence Intervals: 1.1-1.5, P = 0.01). CONCLUSIONS: LC-MS/MS is a clinically useful tool for the diagnosis of non-adherence. Nearly a quarter of TIA patients were non-adherent to their cardiovascular medications Addressing non-adherence early may reduce the risk of future disabling cardiovascular events.


Assuntos
Fármacos Cardiovasculares , Ataque Isquêmico Transitório , Acidente Vascular Cerebral , Fármacos Cardiovasculares/efeitos adversos , Cromatografia Líquida/métodos , Humanos , Ataque Isquêmico Transitório/diagnóstico , Ataque Isquêmico Transitório/tratamento farmacológico , Ataque Isquêmico Transitório/prevenção & controle , Prevenção Secundária , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/prevenção & controle , Espectrometria de Massas em Tandem/métodos
3.
Br J Haematol ; 189(1): 54-66, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32064593

RESUMO

Peripheral T-cell lymphomas (PTCL) comprise a heterogeneous group of aggressive lymphoproliferative disorders almost all of which are associated with poor clinical outcomes. Angioimmunoblastic T-cell lymphoma (AITL) and some peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) have similarities to normal CD4+ T-cell subsets in their gene expression profiles. A cell of origin model is, therefore, emerging and is likely to be refined in the future. Follicular helper (Tfh) T cells are now established as the cell of origin of AITL and about 20% of PTCL-NOS. Sequencing studies have identified recurrent genetic alterations in epigenetic modifiers, T-cell receptor signalling pathway intermediates or RHOA, most commonly a specific mutation leading to RHOA G17V. While PTCL-NOS remains a diagnosis of exclusion, advances in genomics have identified subgroups expressing transcription factors TBX 21 (Th1-like origin) and GATA3 (Th2-like origin). These findings suggest new biomarkers and new therapeutic avenues including the hypomethylating agent azacytidine, or inhibitors of proximal T-cell receptor (TCR) signalling and potentially certain monoclonal antibodies. The advances over the past few years, therefore, prompt stratified medicine approaches to test biologically based treatments and determine the clinical utility of the new disease classifications.


Assuntos
Epigênese Genética/imunologia , Regulação Neoplásica da Expressão Gênica/imunologia , Linfoma de Células T Periférico , Mutação de Sentido Incorreto , Proteínas de Neoplasias , Linfócitos T Auxiliares-Indutores/imunologia , Proteína rhoA de Ligação ao GTP , Humanos , Linfoma de Células T Periférico/classificação , Linfoma de Células T Periférico/genética , Linfoma de Células T Periférico/imunologia , Linfoma de Células T Periférico/terapia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/imunologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/imunologia
4.
Anesthesiology ; 123(3): 548-56, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26068069

RESUMO

BACKGROUND: Malignant hyperthermia (MH) is triggered by reactions to anesthetics. Reports link nonanesthetic-induced MH-like reactions to a variety of disorders. The objective of the authors was to retrospectively investigate the reasons for referrals for MH testing in nonanesthetic cases and assess their phenotype. In addition, the response to the administration of oral dantrolene in nonanesthetic probands with positive caffeine-halothane contracture test (CHCT) was investigated. METHODS: Following institutional research ethics board approval, probands without reaction to anesthesia, who underwent CHCT, were selected. Clinical details and response to dantrolene were analyzed. RESULTS: In total, 87 of 136 (64%) patients referred for nonanesthetic indications tested positive to the CHCT. Of these, 47 with a high creatine kinase (CK), 9 with exercise-induced rhabdomyolysis and/or exercise intolerance, 2 with high CK and exercise-induced rhabdomyolysis and/or exercise intolerance, 15 with postviral chronic fatigue, and 14 with muscle weakness of unknown etiology had a positive CHCT. These patients had a higher CK compared with those with negative CHCT. Oral dantrolene improved the musculoskeletal symptoms in 28 of 34 (82%) CHCT-positive patients. Response to treatment was associated with a significantly higher pretreatment CK and a greater posttreatment CK reduction. CONCLUSIONS: A positive CHCT may represent more than simply an anesthetic-related disorder. Individuals with positive CHCTs may exhibit muscle symptoms without exposure to MH-triggering anesthetics. Oral dantrolene may be useful in alleviating these symptoms.


Assuntos
Anestésicos Inalatórios/efeitos adversos , Cafeína/efeitos adversos , Dantroleno/uso terapêutico , Halotano/efeitos adversos , Hipertermia Maligna/tratamento farmacológico , Adolescente , Adulto , Idoso , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/diagnóstico , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/tratamento farmacológico , Feminino , Humanos , Masculino , Hipertermia Maligna/diagnóstico , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
5.
Psychoneuroendocrinology ; 151: 106070, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36863129

RESUMO

BACKGROUND: The role of the hypothalamic-pituitary-adrenal (HPA) axis in human aggressive behavior is poorly characterized, though some studies report that, unlike depression, circulating or salivary levels of cortisol are low compared with controls. METHODS: In this study, we collected three salivary cortisol levels (two in the morning and one in the evening) on three separate days in 78 adult study participants with (n = 28) and without (n = 52) prominent histories of impulsive aggressive behavior. Plasma C-Reactive Protein (CRP) and Interleukin-6 (IL-6) were also collected in most study participants. Aggressive study participants meet DSM-5 criteria for Intermittent Explosive Disorder (IED) while non-aggressive participants either had a history of a psychiatric disorder or no such history (Controls). RESULTS: Morning, but not evening, salivary cortisol levels were significantly lower in IED (p < 0.05), compared with control, study participants. In addition, salivary cortisol levels correlated with measures of trait anger (partial r = -0.26, p < 0.05) and aggression (partial r = -0.25, p < 0.05) but not with measures of impulsivity, psychopathy, depression, history of childhood maltreatment, or other tested variables that often differ in individuals with IED. Finally, plasma CRP levels correlated inversely with morning salivary cortisol levels (partial r = -0.28, p < 0.05); plasma IL-6 levels showed a similar, though not statistically significant (rp = -0.20, p = 0.12) relationship with morning salivary cortisol levels. CONCLUSION: The cortisol awakening response appears to be lower in individuals with IED compared with controls. In all study participants, morning salivary cortisol levels correlated inversely with trait anger, trait aggression, and plasma CRP, a marker of systemic inflammation. This suggests the present of a complex interaction between chronic-low level inflammation, the HPA axis, and IED that warrants further investigation.


Assuntos
Transtornos Disruptivos, de Controle do Impulso e da Conduta , Hidrocortisona , Adulto , Humanos , Sistema Hipotálamo-Hipofisário , Interleucina-6 , Sistema Hipófise-Suprarrenal , Agressão/fisiologia , Inflamação , Sujeitos da Pesquisa
6.
J Psychiatr Res ; 163: 413-420, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37276645

RESUMO

INTRODUCTION: The modified Taylor Aggression Paradigm (TAP) has been used to study impulsive aggression in experimental designs and has been relatively successful in addressing critiques of aggression paradigms; however, little has been done to examine the potential of using the TAP as a direct measure of aggression. This study aimed to explore the psychometric properties of the TAP behavioral indexes as measures of aggression. METHODS: A community sample of 962 adults were divided into three groups based on diagnostic assessments: Intermittent Explosive Disorder; Non-Aggressive Psychiatric Disorder; or healthy controls. Participants then completed the TAP and self-report measures to assess construct validity. A subset of 47 participants completed a second TAP within one year to assess reliability. TAP indexes were based on number of "extreme" shocks selected (high shock index), average shock levels selected (mean shock index), and shocks levels selected without provocation (unprovoked aggression). RESULTS: Overall, TAP indexes were consistent and reliable. IED participants had the highest high shock and mean shock indexes of all groups (X2 = 49.93, p < 0.001). High shock index was related to trait aggression (ß = 0.184, p < 0.001) after including covariates; mean shock index had a trending association with trait anger (ß = 0.102, p = 0.059). CONCLUSION: TAP behavioral indexes demonstrated promising psychometrics as a measure of aggression. High shock index appears to be more strongly associated with aggressive behavior; mean shock index may better measure general hostile responding. Future research might include comparisons specifically with impulse control disorders.


Assuntos
Transtornos Disruptivos, de Controle do Impulso e da Conduta , Comportamento Impulsivo , Adulto , Humanos , Reprodutibilidade dos Testes , Agressão , Transtornos Disruptivos, de Controle do Impulso e da Conduta/diagnóstico , Ira
7.
Microb Cell Fact ; 11: 96, 2012 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-22830315

RESUMO

Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5) and DHA (C22:6) and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.


Assuntos
Ácidos Graxos Ômega-3/biossíntese , Microalgas/metabolismo , Animais , Organismos Aquáticos/metabolismo , Suplementos Nutricionais/análise , Cadeia Alimentar , Humanos , Engenharia Metabólica , Microalgas/genética
8.
Cancers (Basel) ; 14(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35406544

RESUMO

Transforming growth factor-beta (TGFB) is a critical regulator of normal haematopoiesis. Dysregulation of the TGFB pathway is associated with numerous haematological malignancies including myelofibrosis, acute myeloid leukaemia, and lymphoid disorders. TGFB has classically been seen as a negative regulator of proliferation in haematopoiesis whilst stimulating differentiation and apoptosis, as required to maintain homeostasis. Tumours frequently develop intrinsic resistant mechanisms to homeostatic TGFB signalling to antagonise its tumour-suppressive functions. Furthermore, elevated levels of TGFB enhance pathogenesis through modulation of the immune system and tumour microenvironment. Here, we review recent advances in the understanding of TGFB signalling in B-cell malignancies with a focus on the tumour microenvironment. Malignant B-cells harbour subtype-specific alterations in TGFB signalling elements including downregulation of surface receptors, modulation of SMAD signalling proteins, as well as genetic and epigenetic aberrations. Microenvironmental TGFB generates a protumoural niche reprogramming stromal, natural killer (NK), and T-cells. Increasingly, evidence points to complex bi-directional cross-talk between cells of the microenvironment and malignant B-cells. A greater understanding of intercellular communication and the context-specific nature of TGFB signalling may provide further insight into disease pathogenesis and future therapeutic strategies.

9.
J Psychiatr Res ; 155: 518-525, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36191520

RESUMO

A Lifetime History of Experienced Aggression and a Lifetime History of Witnessed Aggression assessment was developed and its psychometric properties examined in a modest sample of individuals with and without history of psychopathology. Following this, the two assessments were administered to 400 subjects with or without histories of major psychiatric and personality disorders. These studies demonstrated good to excellent psychometric properties as well as evidence of convergent and divergent validity. Since both assessments quantify the occurrence of aggressive behaviors directed at a person and the occurrence of aggressive behaviors witnessed, the researchers propose that these assessments represents a needed modular assessment of aggression in the environment for behavioral science research.


Assuntos
Agressão , Transtornos da Personalidade , Agressão/psicologia , Humanos , Transtornos da Personalidade/diagnóstico , Transtornos da Personalidade/psicologia , Psicometria
10.
Arch Suicide Res ; 26(3): 1060-1071, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33275544

RESUMO

We examined whether the analgesic effect of alcohol mediates the association between alcohol and deliberate self-harm (DSH) using data from a larger study on alcohol effects. Men (n = 106) and women (n = 104) low-risk alcohol drinkers (ages M = 26.00, SD = 6.98) recruited from the community who had no suicide attempt or episode of deliberate self-harm within the past year were randomly assigned to either a placebo drink condition or a drink calibrated to reach approximately .050%, .075%, or .100% blood alcohol concentration. Notable within-condition BAC variability, as well as overlap between conditions, suggested that BAC would be a more accurate indicator of intoxication compared to condition assignment. Pain tolerance was assessed by increasingly intense 1-s shocks delivered via fingertip electrodes. Self-reported pain associated with the pain tolerance index was also examined. A laboratory task of DSH, the Self-Aggression Paradigm, was then completed, with DSH operationalized as the number of self-administered shocks the participant was led to believe were twice the intensity of his or her pain tolerance and could cause "minor tissue damage that would quickly heal." A negative binomial parallel mediational model for count data revealed that pain tolerance, but not self-report pain, mediated the effect of alcohol on DSH. As such, the current study provides preliminary experimental evidence that the analgesic effect of alcohol is partially responsible for link between alcohol intoxication and deliberate self-harm.


Assuntos
Intoxicação Alcoólica , Comportamento Autodestrutivo , Analgésicos , Concentração Alcoólica no Sangue , Feminino , Humanos , Masculino , Dor , Fatores de Risco
11.
J Cannabis Res ; 4(1): 51, 2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36138416

RESUMO

BACKGROUND: Hemp (Cannabis sativa L.) is a producer of cannabinoids. These organic compounds are of increasing interest due to their potential applications in the medicinal field. Advances in analytical methods of identifying and quantifying these molecules are needed. METHOD: This study describes a new method of cannabinoid separation from plant material using gas chromatography-mass spectrometry (GC-MS) as the analytical tool to detect low abundance cannabinoids that will likely have implications for future therapeutical treatments. A novel approach was adopted to separate trichomes from plant material to analyse cannabinoids of low abundance not observed in raw plant extract. Required plant sample used for analysis was greatly reduced compared to other methods. Derivatisation method was simplified and deconvolution software was utilised to recognise unknown cannabinoid compounds of low abundance. RESULTS: The method produces well-separated spectra and allows the detection of major and minor cannabinoids. Ten cannabinoids that had available standards could be identified and quantified and numerous unidentified cannabinoids or pathway intermediates based on GC-MS spectra similarities could be extracted and analysed simultaneously with this method. CONCLUSIONS: This is a rapid novel extraction and analytical method from plant material that can identify major and minor cannabinoids using a simple technique. The method will be of use to future researchers seeking to study the multitude of cannabinoids whose values are currently not understood.

12.
Am J Obstet Gynecol ; 204(6): 546.e10-7, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21481833

RESUMO

OBJECTIVE: The objective of the study was to explore the maternal-fetal pharmacokinetics of intraamniotic (IA), intravenous (IV), or intramuscular (IM) administration of erythromycin or azithromycin in a pregnant sheep model. STUDY DESIGN: Pregnant ewes of 115-121 days' gestation received a single maternal IV infusion (5 mg/kg over 60 min), a single IM injection, or a single IA injection (3.2 mg/kg fetal weight) of either erythromycin lactobionate or azithromycin. Maternal/fetal blood and amniotic fluid (AF) samples were collected across 48 h for macrolide assay by liquid chromatography and tandem mass spectrometry. RESULTS: Maternal administration achieved therapeutic maternal plasma macrolide concentrations (≥0.5 µg/mL) with low concentrations in AF equivalent to less than 7% transfer; fetal plasma levels were even lower (<1.5% transfer). The IA administration achieved therapeutic concentrations in AF and sustained for 48 h, with poor maternal-fetal transfer (<1% maternal, <0.3% fetal). Modest pharmacokinetic differences were evident between erythromycin and azithromycin. CONCLUSION: Maternal macrolide administration achieves subtherapeutic concentrations in AF or fetal plasma, whereas a single IA injection achieves therapeutic concentrations in AF but not in maternal-fetal circulations. Combined maternal and single IA administration of macrolides may be a more effective regimen for treatment of intrauterine, but not fetal, infection.


Assuntos
Âmnio/metabolismo , Antibacterianos/farmacocinética , Azitromicina/farmacocinética , Eritromicina/farmacocinética , Feto/metabolismo , Líquido Amniótico/química , Animais , Antibacterianos/administração & dosagem , Antibacterianos/sangue , Azitromicina/administração & dosagem , Azitromicina/sangue , Eritromicina/administração & dosagem , Eritromicina/sangue , Feminino , Sangue Fetal , Injeções , Injeções Intramusculares , Injeções Intravenosas , Gravidez , Ovinos , Distribuição Tecidual
13.
Arch Suicide Res ; 24(sup1): 231-242, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30636569

RESUMO

Research supports the notion that alcohol intoxication is a risk factor for deliberate self-harm (DSH). However, the underlying mechanisms for this relationship are poorly understood. We aimed to determine whether alcohol-induced dissociation mediated alcohol's effects on DSH. We used data from a dose-response study of alcohol intoxication and DSH to test the proposed model. Participants were assigned to reach target blood alcohol concentrations (BAC) ranging from 0.00% through 0.10% and then completed a behavioral measure of DSH. Dissociation was assessed using the Alcohol Dissociative Experiences Scale. BAC predicted both dissociation and DSH, but dissociation did not predict DSH. Although research on clinical populations suggests dissociation is related to DSH, our findings suggest dissociation does not mediate the effects of alcohol on self-harm.


Assuntos
Intoxicação Alcoólica/psicologia , Transtornos Dissociativos/psicologia , Comportamento Autodestrutivo/psicologia , Adulto , Concentração Alcoólica no Sangue , Feminino , Humanos , Masculino , Análise de Mediação , Pessoa de Meia-Idade , Fatores de Risco , Adulto Jovem
14.
Blood Adv ; 4(15): 3586-3593, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32761231

RESUMO

High-dose methotrexate (HD-MTX) is increasingly used as prophylaxis for patients with diffuse large B-cell lymphoma (DLBCL) at high risk of central nervous system (CNS) relapse. However, there is limited evidence to guide whether to intercalate HD-MTX (i-HD-MTX) between R-CHOP-21 (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone given at 21-day intervals) or to give it at the end of treatment (EOT) with R-CHOP-21. We conducted a retrospective, multicenter analysis of 334 patients with DLBCL who received CNS prophylaxis with i-HD-MTX (n = 204) or EOT HD-MTX (n = 130). Primary end points were R-CHOP delay rates and HD-MTX toxicity. Secondary end points were CNS relapse rate, progression-free survival, and overall survival. The EOT group had more patients with a high CNS international prognostic index (58% vs 39%; P < .001) and more concurrent intrathecal prophylaxis (56% vs 34%; P < .001). Of the 409 cycles of i-HD-MTX given, 82 (20%) were associated with a delay of next R-CHOP (median, 7 days). Delays were significantly increased when i-HD-MTX was given after day 9 post-R-CHOP (26% vs 16%; P = .01). On multivariable analysis, i-HD-MTX was independently associated with increased R-CHOP delays. Increased mucositis, febrile neutropenia, and longer median inpatient stay were recorded with i-HD-MTX delivery. Three-year cumulative CNS relapse incidence was 5.9%, with no differences between groups. There was no difference in survival between groups. We report increased toxicity and R-CHOP delay with i-HD-MTX compared with EOT delivery but no difference in CNS relapse or survival. Decisions on HD-MTX timing should be individualized and, where i-HD-MTX is favored, we recommend scheduling before day 10 of R-CHOP cycles.


Assuntos
Neoplasias do Sistema Nervoso Central , Linfoma Difuso de Grandes Células B , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Ciclofosfamida/efeitos adversos , Doxorrubicina/efeitos adversos , Humanos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Metotrexato/efeitos adversos , Recidiva Local de Neoplasia/tratamento farmacológico , Estudos Retrospectivos , Rituximab/efeitos adversos , Vincristina/efeitos adversos
15.
J Exp Bot ; 60(6): 1691-702, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19342428

RESUMO

A select set of microalgae are reported to be able to catalyse photobiological H(2) production from water. Based on the model organism Chlamydomonas reinhardtii, a method was developed for the screening of naturally occurring H(2)-producing microalgae. By purging algal cultures with N(2) in the dark and subsequent illumination, it is possible to rapidly induce photobiological H(2) evolution. Using NMR spectroscopy for metabolic profiling in C. reinhardtii, acetate, formate, and ethanol were found to be key compounds contributing to metabolic variance during the assay. This procedure can be used to test algal species existing as axenic or mixed cultures for their ability to produce H(2). Using this system, five algal isolates capable of H(2) production were identified in various aquatic systems. A phylogenetic tree was constructed using ribosomal sequence data of green unicellular algae to determine if there were taxonomic patterns of H(2) production. H(2)-producing algal species were seen to be dispersed amongst most clades, indicating an H(2)-producing capacity preceded evolution of the phylum Chlorophyta.


Assuntos
Clorófitas/genética , Clorófitas/metabolismo , Hidrogênio/metabolismo , Filogenia , Clorófitas/classificação , Clorófitas/isolamento & purificação , DNA de Algas/genética , DNA Ribossômico/genética , Luz , RNA Ribossômico 18S/genética , Água do Mar
16.
Eukaryot Cell ; 7(11): 1965-79, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18708561

RESUMO

Photobiological hydrogen production using microalgae is being developed into a promising clean fuel stream for the future. In this study, microarray analyses were used to obtain global expression profiles of mRNA abundance in the green alga Chlamydomonas reinhardtii at different time points before the onset and during the course of sulfur-depleted hydrogen production. These studies were followed by real-time quantitative reverse transcription-PCR and protein analyses. The present work provides new insights into photosynthesis, sulfur acquisition strategies, and carbon metabolism-related gene expression during sulfur-induced hydrogen production. A general trend toward repression of transcripts encoding photosynthetic genes was observed. In contrast to all other LHCBM genes, the abundance of the LHCBM9 transcript (encoding a major light-harvesting polypeptide) and its protein was strongly elevated throughout the experiment. This suggests a major remodeling of the photosystem II light-harvesting complex as well as an important function of LHCBM9 under sulfur starvation and photobiological hydrogen production. This paper presents the first global transcriptional analysis of C. reinhardtii before, during, and after photobiological hydrogen production under sulfur deprivation.


Assuntos
Clorófitas/genética , Clorófitas/metabolismo , Perfilação da Expressão Gênica , Hidrogênio/metabolismo , Fotossíntese , Enxofre/metabolismo , Proteínas de Algas/genética , Proteínas de Algas/metabolismo , Aminoácidos/metabolismo , Clorófitas/efeitos da radiação , Complexos de Proteínas Captadores de Luz/genética , Complexos de Proteínas Captadores de Luz/metabolismo , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Biossíntese de Proteínas , Transcrição Gênica
17.
PLoS One ; 7(5): e37382, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22629387

RESUMO

Current knowledge suggests that the mechanisms by which plants communicate information take numerous forms. Previous studies have focussed their attention on communication via chemicals, contact and light; other methods of interaction between plants have remained speculative. In this study we tested the ability of young chilli plants to sense their neighbours and identify their relatives using alternative mechanism(s) to recognised plant communication pathways. We found that the presence of a neighbouring plant had a significant influence on seed germination even when all known sources of communication signals were blocked. Furthermore, despite the signalling restriction, seedlings allocated energy to their stem and root systems differently depending on the identity of the neighbour. These results provide clear experimental evidence for the existence of communication channels between plants beyond those that have been recognized and studied thus far.


Assuntos
Capsicum/fisiologia , Raízes de Plantas/metabolismo , Transdução de Sinais/fisiologia , Capsicum/crescimento & desenvolvimento , Capsicum/metabolismo , Germinação , Luz
18.
Plant Signal Behav ; 7(10): 1346-8, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22902698

RESUMO

Over the last two decades, important insights into our understanding of plant ecology and the communicative nature of plants have not only confirmed the existence of a wide range of communication means used by plants, but most excitingly have indicated that more modalities remain to be discovered. In fact, we have recently found that seeds and seedlings of the chili plant, Capsicum annuum, are able to sense neighbors and identify relatives using alternative mechanisms beyond previously studied channels of plant communication. In this addendum, we offer a hypothetical mechanistic explanation as to how plants may do this by quantum-assisted magnetic and/or acoustic sensing and signaling. If proven correct, this hypothesis prompts for a re-interpretation of our current understanding of plasticity in germination and growth of plants and more generally, calls for developing a new perspective of these biological phenomena.


Assuntos
Acústica , Fenômenos Magnéticos , Fenômenos Fisiológicos Vegetais , Ecossistema , Publicações , Sementes/fisiologia
19.
PLoS One ; 7(7): e40751, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22792403

RESUMO

Microalgae have been widely reported as a promising source of biofuels, mainly based on their high areal productivity of biomass and lipids as triacylglycerides and the possibility for cultivation on non-arable land. The isolation and selection of suitable strains that are robust and display high growth and lipid accumulation rates is an important prerequisite for their successful cultivation as a bioenergy source, a process that can be compared to the initial selection and domestication of agricultural crops. We developed standard protocols for the isolation and cultivation for a range of marine and brackish microalgae. By comparing growth rates and lipid productivity, we assessed the potential of subtropical coastal and brackish microalgae for the production of biodiesel and other oil-based bioproducts. This study identified Nannochloropsis sp., Dunaniella salina and new isolates of Chlorella sp. and Tetraselmis sp. as suitable candidates for a multiple-product algae crop. We conclude that subtropical coastal microalgae display a variety of fatty acid profiles that offer a wide scope for several oil-based bioproducts, including biodiesel and omega-3 fatty acids. A biorefinery approach for microalgae would make economical production more feasible but challenges remain for efficient harvesting and extraction processes for some species.


Assuntos
Água Doce , Microalgas/isolamento & purificação , Microalgas/metabolismo , Triglicerídeos/biossíntese , Biocombustíveis , Ácidos Graxos/química , Microalgas/genética , Microalgas/crescimento & desenvolvimento , Filogenia , RNA Ribossômico 18S/genética
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