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1.
Nature ; 608(7923): 558-562, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35948632

RESUMO

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.


Assuntos
Mudança Climática , Fósforo , Floresta Úmida , Solo , Árvores , Clima Tropical , Aclimatação , Dióxido de Carbono/metabolismo , Dióxido de Carbono/farmacologia , Sequestro de Carbono , Cátions/metabolismo , Cátions/farmacologia , Mudança Climática/estatística & dados numéricos , Modelos Biológicos , Nitrogênio/metabolismo , Nitrogênio/farmacologia , Fósforo/metabolismo , Fósforo/farmacologia , Solo/química , Árvores/efeitos dos fármacos , Árvores/metabolismo , Incerteza
2.
NMR Biomed ; 37(5): e5108, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38273732

RESUMO

Functional MRI (fMRI) and MRS (fMRS) can be used to noninvasively map cerebral activation and metabolism. Recently, hyperpolarized 13C spectroscopy and metabolic imaging have provided an alternative approach to assess metabolism. In this study, we combined 1H fMRI and hyperpolarized [1-13C]pyruvate MRS to compare cerebral blood oxygenation level-dependent (BOLD) response and real-time cerebral metabolism, as assessed with lactate and bicarbonate labelling, during nicotine stimulation. Simultaneous 1H fMRI (multislice gradient echo echo-planar imaging) and 13C spectroscopic (single slice pulse-acquire) data were collected in urethane-anaesthetized female Sprague-Dawley rats (n = 12) at 9.4 T. Animals received an intravenous (i.v.) injection of either nicotine (stimulus; 88 µg/kg, n = 7, or 300 µg/kg, n = 5) or 0.9% saline (matching volume), followed by hyperpolarized [1-13C]pyruvate injection 60 s later. Three hours later, a second injection was administered: the animals that had previously received saline were injected with nicotine and vice versa, both followed by another hyperpolarized [1-13C]pyruvate i.v. injection 60 s later. The low-dose (88 µg/kg) nicotine injection led to a 12% ± 4% (n = 7, t-test, p ~ 0.0006 (t-value -5.8, degrees of freedom 6), Wilcoxon p ~ 0.0078 (test statistic 0)) increase in BOLD signal. At the same time, an increase in 13C-bicarbonate signal was seen in four out of six animals. Bicarbonate-to-total carbon ratios were 0.010 ± 0.004 and 0.018 ± 0.010 (n = 6, t-test, p ~ 0.03 (t-value -2.3, degrees of freedom 5), Wilcoxon p ~ 0.08 (test statistic 3)) for saline and nicotine experiments, respectively. No increase in the lactate signal was seen; lactate-to-total carbon was 0.16 ± 0.02 after both injections. The high (300 µg/kg) nicotine dose (n = 5) caused highly variable BOLD and metabolic responses, possibly due to the apparent respiratory distress. Simultaneous detection of 1H fMRI and hyperpolarized 13C-MRS is feasible. A comparison of metabolic response between control and stimulated states showed differences in bicarbonate signal, implying that the hyperpolarization technique could offer complimentary information on brain activation.


Assuntos
Imageamento por Ressonância Magnética , Ácido Pirúvico , Ratos , Feminino , Animais , Imageamento por Ressonância Magnética/métodos , Ácido Pirúvico/metabolismo , Nicotina/farmacologia , Ratos Sprague-Dawley , Bicarbonatos/metabolismo , Isótopos de Carbono/metabolismo , Ácido Láctico/metabolismo
3.
J Appl Microbiol ; 135(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38444193

RESUMO

AIM: This study aimed to compare and characterize the resistance profile and the presence of extended-spectrum beta-lactamase (ESBL) related genes in Escherichia coli isolated from healthy finishing pigs fed with or without antibiotics in their diets. METHODS AND RESULTS: A total of 27 ceftiofur-resistant E. coli isolates were obtained from 96 healthy pigs. The antibiotic resistance profile was tested, and all 27 isolates were classified as multidrug-resistant (MDR). A high proportion of isolates were resistant to cephalosporins, ampicillin, ciprofloxacin, and tetracyclines. The ESBL production was observed in 85% of isolates by double-disc synergy test. The MDR-E. coli isolates harbored ESBL genes, such as blaTEM, blaCTX-M-1, blaCTX-M-2, and blaCTX-M-8,25. In addition, other antibiotics resistance genes (ARGs) were also detected, such as sul2, ant(3″)-I, tetA, and mcr-1. The mobilization of the blaCTX-M gene was confirmed for nine E. coli isolates by conjugation assays. The presence of blaCTX-M on mobile genetic elements in these isolates was demonstrated by Southern blot hybridization, and the resistance to cephalosporins was confirmed in the transconjugants. Our results indicate the prevalence of CTX-M-producing E. coli strains harboring mobile genetic elements in the normal microbiota of healthy pigs. CONCLUSIONS: These findings highlight the significance of ESBL genes as a global health concern in livestock and the potential spread of antimicrobial resistance to other members of the gastrointestinal tract microbiota.


Assuntos
Infecções por Escherichia coli , Escherichia coli , Animais , Suínos , Gado , Prevalência , beta-Lactamases/genética , beta-Lactamases/metabolismo , Cefalosporinas/farmacologia , Antibacterianos/farmacologia , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/veterinária , Farmacorresistência Bacteriana Múltipla/genética , Plasmídeos
4.
Chemphyschem ; 24(19): e202300100, 2023 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-37431722

RESUMO

This paper reports the synthesis, characterization and in vivo application of water-soluble supramolecular contrast agents (Mw: 5-5.6 kDa) for MRI obtained from ß-cyclodextrin functionalized with different kinds of nitroxide radicals, both with piperidine structure (CD2 and CD3) and with pyrrolidine structure (CD4 and CD5). As to the stability of the radicals in presence of ascorbic acid, CD4 and CD5 have low second order kinetic constants (≤0.05 M-1 s-1 ) compared to CD2 (3.5 M-1 s-1 ) and CD3 (0.73 M-1 s-1 ). Relaxivity (r1 ) measurements on compounds CD3-CD5 were carried out at different magnetic field strength (0.7, 3, 7 and 9.4 T). At 0.7 T, r1 values comprised between 1.5 mM-1 s-1 and 1.9 mM-1 s-1 were found while a significant reduction was observed at higher fields (r1 ≈0.6-0.9 mM-1 s-1 at 9.4 T). Tests in vitro on HEK293 human embryonic kidney cells, L929 mouse fibroblasts and U87 glioblastoma cells indicated that all compounds were non-cytotoxic at concentrations below 1 µmol mL-1 . MRI in vivo was carried out at 9.4 T on glioma-bearing rats using the compounds CD3-CD5. The experiments showed a good lowering of T1 relaxation in tumor with a retention of the contrast for at least 60 mins confirming improved stability also in vivo conditions.


Assuntos
Meios de Contraste , Ciclodextrinas , Camundongos , Ratos , Humanos , Animais , Meios de Contraste/toxicidade , Meios de Contraste/química , Células HEK293 , Imageamento por Ressonância Magnética/métodos , Oxirredução
5.
Am J Public Health ; 113(12): 1263-1266, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37797279

RESUMO

Racial/ethnic disparities in the administration of mpox vaccine in Fulton County, Georgia, threatened to undermine the effectiveness of the response. To counteract this inequity, the Fulton County Board of Health partnered with local agencies serving Black and Latino men who have sex with men to coordinate efforts and reserve blocks of time for clients of these agencies to receive a vaccine. The disparities were reversed and approached equity with case rates. (Am J Public Health. 2023;113(12):1263-1266. https://doi.org/10.2105/AJPH.2023.307416).


Assuntos
Disparidades em Assistência à Saúde , Mpox , Vacina Antivariólica , Humanos , Masculino , Georgia , Hispânico ou Latino , Grupos Raciais , Mpox/prevenção & controle , Negro ou Afro-Americano
6.
Int J Mol Sci ; 24(22)2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-38003438

RESUMO

Rett Syndrome is an X-linked neurodevelopmental disorder (RTT; OMIM#312750) associated to MECP2 mutations. MeCP2 dysfunction is seen as one cause for the deficiencies found in brain-derived neurotrophic factor (BDNF) signaling, since BDNF is one of the genes under MeCP2 jurisdiction. BDNF signaling is also dependent on the proper function of the adenosinergic system. Indeed, both BDNF signaling and the adenosinergic system are altered in Mecp2-null mice (Mecp2-/y), a representative model of severe manifestation of RTT. Considering that symptoms severity largely differs among RTT patients, we set out to investigate the BDNF and ADO signaling modifications in Mecp2 heterozygous female mice (Mecp2+/-) presenting a less severe phenotype. Symptomatic Mecp2+/- mice have lower BDNF levels in the cortex and hippocampus. This is accompanied by a loss of BDNF-induced facilitation of hippocampal long-term potentiation (LTP), which could be restored upon selective activation of adenosine A2A receptors (A2AR). While no differences were observed in the amount of adenosine in the cortex and hippocampus of Mecp2+/- mice compared with healthy littermates, the density of the A1R and A2AR subtype receptors was, respectively, upregulated and downregulated in the hippocampus. Data suggest that significant changes in BDNF and adenosine signaling pathways are present in an RTT model with a milder disease phenotype: Mecp2+/- female animals. These features strengthen the theory that boosting adenosinergic activity may be a valid therapeutic strategy for RTT patients, regardless of their genetic penetrance.


Assuntos
Fator Neurotrófico Derivado do Encéfalo , Síndrome de Rett , Animais , Feminino , Humanos , Camundongos , Adenosina/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Estudos Transversais , Modelos Animais de Doenças , Proteína 2 de Ligação a Metil-CpG/genética , Proteína 2 de Ligação a Metil-CpG/metabolismo , Camundongos Knockout , Síndrome de Rett/metabolismo
7.
Environ Monit Assess ; 194(7): 482, 2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35668330

RESUMO

Bananas are a worldwide cultivated crop and one of the main agricultural activities in Brazil. The banana orchards cultivated in the region of São Paulo State are under native areas of the Atlantic Forest biome. The Atlantic Forest has suffered agricultural and urban pressure for many years. Banana crops require soil management and superficial vegetation removal in the first cycles. We conducted a study aiming to understand the impact of long-standing banana cultivation in the Atlantic forest region. Soil samples in banana plantations (EBP) and forest remnants (FR) were collected from trenches with 0- to 100-cm layers. The soil bulk density in EBP until 30-cm depth was 12.76% higher than that in FR. Quantifications of macropores and micropores in FR reached values higher than those in EBP. The results showed that carbon stocks decreased from the top to the deeper layers. Thirty years after the conversion, the FR treatment accumulated 28.23% more carbon than EBP. Considering our results, it was evident that changes in physical and chemical properties reflected the negative impacts of the banana plantations, cropped through conventional management, when converted from forest even in regard to a remnant one. These findings, showed for the first time, lead us to understand the soil management of banana plantations, following conventional agriculture systems, as a potential carbon stock reducer and a factor resulting in the loss of soil quality in the region. Additionally, our data can be used by environmentalists and government policymakers to promote environmental sustainability.


Assuntos
Musa , Solo , Agricultura , Brasil , Carbono/análise , Monitoramento Ambiental , Florestas , Solo/química
8.
New Phytol ; 230(1): 116-128, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33341935

RESUMO

Soil nutrient availability can strongly affect root traits. In tropical forests, phosphorus (P) is often considered the main limiting nutrient for plants. However, support for the P paradigm is limited, and N and cations might also control tropical forests functioning. We used a large-scale experiment to determine how the factorial addition of nitrogen (N), P and cations affected root productivity and traits related to nutrient acquisition strategies (morphological traits, phosphatase activity, arbuscular mycorrhizal colonisation and nutrient contents) in a primary rainforest growing on low-fertility soils in Central Amazonia after 1 yr of fertilisation. Multiple root traits and productivity were affected. Phosphorus additions increased annual root productivity and root diameter, but decreased root phosphatase activity. Cation additions increased root productivity at certain times of year, also increasing root diameter and mycorrhizal colonisation. P and cation additions increased their element concentrations in root tissues. No responses were detected with N addition. Here we showed that rock-derived nutrients determined root functioning in low-fertility Amazonian soils, demonstrating not only the hypothesised importance of P, but also highlighting the role of cations. The changes in fine root traits and productivity indicated that even slow-growing tropical rainforests can respond rapidly to changes in resource availability.


Assuntos
Fósforo , Clima Tropical , Cátions , Florestas , Nitrogênio/análise , Raízes de Plantas/química , Solo , Árvores
9.
Neurobiol Dis ; 145: 105043, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32798727

RESUMO

Rett syndrome (RTT; OMIM#312750) is mainly caused by mutations in the X-linked MECP2 gene (methyl-CpG-binding protein 2 gene; OMIM*300005), which leads to impairments in the brain-derived neurotrophic factor (BDNF) signalling. The boost of BDNF mediated effects would be a significant breakthrough but it has been hampered by the difficulty to administer BDNF to the central nervous system. Adenosine, an endogenous neuromodulator, may accomplish that role since through A2AR it potentiates BDNF synaptic actions in healthy animals. We thus characterized several hallmarks of the adenosinergic and BDNF signalling in RTT and explored whether A2AR activation could boost BDNF actions. For this study, the RTT animal model, the Mecp2 knockout (Mecp2-/y) (B6.129P2 (C)-Mecp2tm1.1Bird/J) mouse was used. Whenever possible, parallel data was also obtained from post-mortem brain samples from one RTT patient. Ex vivo extracellular recordings of field excitatory post-synaptic potentials in CA1 hippocampal area were performed to evaluate synaptic transmission and long-term potentiation (LTP). RT-PCR was used to assess mRNA levels and Western Blot or radioligand binding assays were performed to evaluate protein levels. Changes in cortical and hippocampal adenosine content were assessed by liquid chromatography with diode array detection (LC/DAD). Hippocampal ex vivo experiments revealed that the facilitatory actions of BDNF upon LTP is absent in Mecp2-/y mice and that TrkB full-length (TrkB-FL) receptor levels are significantly decreased. Extracts of the hippocampus and cortex of Mecp2-/y mice revealed less adenosine amount as well as less A2AR protein levels when compared to WT littermates, which may partially explain the deficits in adenosinergic tonus in these animals. Remarkably, the lack of BDNF effect on hippocampal LTP in Mecp2-/y mice was overcome by selective activation of A2AR with CGS21680. Overall, in Mecp2-/y mice there is an impairment on adenosinergic system and BDNF signalling. These findings set the stage for adenosine-based pharmacological therapeutic strategies for RTT, highlighting A2AR as a therapeutic target in this devastating pathology.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Receptor A1 de Adenosina/metabolismo , Receptor A2A de Adenosina/metabolismo , Síndrome de Rett/metabolismo , Transdução de Sinais/fisiologia , Animais , Hipocampo/metabolismo , Proteína 2 de Ligação a Metil-CpG , Camundongos , Camundongos Knockout , Receptor trkB/metabolismo , Síndrome de Rett/genética
10.
Vet Anaesth Analg ; 46(1): 79-83, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30528215

RESUMO

OBJECTIVE: To evaluate the anaesthetic effects of three different alfaxalone doses to induce anaesthesia in goldfish. STUDY DESIGN: Prospective, randomized, clinical study. ANIMALS: Thirty goldfish undergoing skin scraping, gill examination and stool collection. METHODS: Each fish was transferred to an individual 4 L induction tank and randomly allocated into one of three groups (n = 10), in which alfaxalone was administered at concentrations of 6, 7 or 9 mg L-1. The depth of anaesthesia was evaluated by approach reaction, equilibrium, opercular movement and reaction to tactile stimuli. Sedation, light anaesthesia, surgical anaesthesia and recovery times were recorded. Data were analyzed with analysis of variance. A p value <0.05 was considered significant. RESULTS: Surgical anaesthesia was achieved in all fish. Goldfish induced with alfaxalone 7 and 9 mg L-1 showed a mild excitement phase. Time to sedation of the 6 mg L-1 dose (5.89 ± 0.40 minutes) was significantly longer compared to the 7 mg L-1 (3.97 ± 0.40 minutes) and 9 mg L-1 doses (3.94 ± 0.40 minutes). Times to light anaesthesia and surgical anaesthesia of the 9 mg L-1 dose (7.65 ± 1.04 and 9.60 ± 1.84 minutes, respectively) were significantly faster compared with those of the 6 mg L-1 dose (13.79 ± 1.04 and 19.75 ± 1.84 minutes, respectively) and the 7 mg L-1 dose (13.55 ± 1.04 and 21.24 ± 1.84 minutes, respectively). No significant differences were recorded in recovery time. Cessation of opercular movement was recorded in two fish induced with 7 mg L-1 and in two induced with 9 mg L-1. No mortality occurred. CONCLUSIONS: and clinical relevance Alfaxalone is a reliable agent for immersion anaesthesia in goldfish. Immersion in water containing 6 mg alfaxalone L-1 provided smooth induction of anaesthesia, and no obvious side effects were encountered. Higher doses shortened induction time and caused respiratory depression and excitatory movements.


Assuntos
Anestesia/veterinária , Anestésicos/farmacologia , Carpa Dourada/fisiologia , Pregnanodionas/farmacologia , Anestésicos/administração & dosagem , Animais , Relação Dose-Resposta a Droga , Imersão , Pregnanodionas/administração & dosagem , Distribuição Aleatória , Resultado do Tratamento
11.
Biochim Biophys Acta ; 1819(3-4): 349-55, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24459737

RESUMO

Candida albicans is the most prevalent human fungal pathogen. To successfully propagate an infection, this organism relies on the ability to change morphology, express virulence-associated genes and resist DNA damage caused by the host immune system. Many of these events involve chromatin alterations that are crucial for virulence. This review will focus on the studies that have been conducted on how chromatin function affects pathogenicity of C. albicans and other fungi. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.


Assuntos
Candida albicans/patogenicidade , Cromatina/fisiologia , Candidíase/genética , Candidíase/microbiologia , Reparo do DNA/fisiologia , Instabilidade Genômica , Interações Hospedeiro-Patógeno/genética , Humanos , Transcrição Gênica/fisiologia , Virulência/genética
12.
Neurobiol Learn Mem ; 113: 55-61, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24161888

RESUMO

We investigate whether the extinction of inhibitory avoidance (IA) learning can be subjected to endogenous state-dependence with systemic injections of epinephrine (E), and whether endogenous norepinephrine (NE) and the nucleus tractus solitarius (NTS)→locus coeruleus→hippocampus/amygdala (HIPP/BLA) pathway participate in this. Rats trained in IA were submitted to two sessions of extinction 24 h apart: In the first, the animals were submitted to a training session of extinction, and in the second they were tested for the retention of extinction. Saline or E were given i.p. immediately after the extinction training (post-extinction training injections) and/or 6 min before the extinction test (pre-extinction test). Post-extinction training E (50 or 100 µg/kg) induced a poor retrieval of extinction in the test session of this task unless an additional E injection (50 µg/kg) was given prior to the extinction test. This suggested state-dependence. Muscimol (0.01 µg/side) microinfused into the NTS prior to the extinction test session blocked E-induced state-dependence. Norepinephrine (NE, 1 µg/side) infused bilaterally into NTS restores the extinction impairment caused by post-extinction training i.p. E. In animals with bilateral NTS blockade induced by muscimol, NE (1 µg/side) given prior to the extinction test into the CA1 region of the dorsal hippocampus or into the basolateral amygdala restored the normal extinction levels that had been impaired by muscimol. These results suggest a role for the NTS→locus coeruleus→HIPP/BLA pathway in the retrieval of extinction, as it has been shown to have in the consolidation of inhibitory avoidance and of object recognition learning.


Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem da Esquiva/fisiologia , Epinefrina/fisiologia , Extinção Psicológica/fisiologia , Hipocampo/fisiologia , Locus Cerúleo/fisiologia , Norepinefrina/fisiologia , Transdução de Sinais/fisiologia , Núcleo Solitário/fisiologia , Tonsila do Cerebelo/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Epinefrina/administração & dosagem , Extinção Psicológica/efeitos dos fármacos , Medo/fisiologia , Agonistas de Receptores de GABA-A/administração & dosagem , Agonistas de Receptores de GABA-A/farmacologia , Hipocampo/efeitos dos fármacos , Locus Cerúleo/efeitos dos fármacos , Masculino , Muscimol/administração & dosagem , Muscimol/farmacologia , Norepinefrina/administração & dosagem , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Núcleo Solitário/efeitos dos fármacos
13.
Biochim Biophys Acta ; 1819(3-4): 349-55, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21888998

RESUMO

Candida albicans is the most prevalent human fungal pathogen. To successfully propagate an infection, this organism relies on the ability to change morphology, express virulence-associated genes and resist DNA damage caused by the host immune system. Many of these events involve chromatin alterations that are crucial for virulence. This review will focus on the studies that have been conducted on how chromatin function affects pathogenicity of C. albicans and other fungi. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.

14.
Bioorg Med Chem Lett ; 23(10): 2853-9, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23587423

RESUMO

The histone acetyltransferase Rtt109 is the sole enzyme responsible for acetylation of histone H3 lysine 56 (H3K56) in fungal organisms. Loss of Rtt109 renders fungal cells extremely sensitive to genotoxic agents, and prevents pathogenesis in several clinically important species. Here, via a high throughput chemical screen of >300,000 compounds, we discovered a chemical inhibitor of Rtt109 that does not inhibit other acetyltransferase enzymes. This compound inhibits Rtt109 regardless of which histone chaperone cofactor protein (Asf1 or Vps75) is present, and appears to inhibit Rtt109 via a tight-binding, uncompetitive mechanism.


Assuntos
Inibidores Enzimáticos/farmacologia , Histona Acetiltransferases/antagonistas & inibidores , Proteínas de Saccharomyces cerevisiae/antagonistas & inibidores , Saccharomyces/enzimologia , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Histona Acetiltransferases/metabolismo , Estrutura Molecular , Proteínas de Saccharomyces cerevisiae/metabolismo , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-Atividade
15.
Proc Natl Acad Sci U S A ; 107(4): 1594-9, 2010 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-20080646

RESUMO

Candida albicans is a ubiquitous opportunistic pathogen that is the most prevalent cause of hospital-acquired fungal infections. In mammalian hosts, C. albicans is engulfed by phagocytes that attack the pathogen with DNA-damaging reactive oxygen species (ROS). Acetylation of histone H3 lysine 56 (H3K56) by the fungal-specific histone acetyltransferase Rtt109 is important for yeast model organisms to survive DNA damage and maintain genome integrity. To assess the importance of Rtt109 for C. albicans pathogenicity, we deleted the predicted homolog of Rtt109 in the clinical C. albicans isolate, SC5314. C. albicans rtt109(-/-) mutant cells lack acetylated H3K56 (H3K56ac) and are hypersensitive to genotoxic agents. Additionally, rtt109(-/-) mutant cells constitutively display increased H2A S129 phosphorylation and elevated DNA repair gene expression, consistent with endogenous DNA damage. Importantly, C. albicans rtt109(-/-) cells are significantly less pathogenic in mice and more susceptible to killing by macrophages in vitro than are wild-type cells. Via pharmacological inhibition of the host NADPH oxidase enzyme, we show that the increased sensitivity of rtt109(-/-) cells to macrophages depends on the host's ability to generate ROS, providing a mechanistic link between the drug sensitivity, gene expression, and pathogenesis phenotypes. We conclude that Rtt109 is particularly important for fungal pathogenicity, suggesting a unique target for therapeutic antifungal compounds.


Assuntos
Candida albicans/enzimologia , Candidíase/microbiologia , Histona Acetiltransferases/metabolismo , Animais , Candida albicans/genética , Candida albicans/crescimento & desenvolvimento , Candida albicans/patogenicidade , Sobrevivência Celular , Reparo do DNA , DNA Fúngico/genética , DNA Fúngico/metabolismo , Feminino , Regulação Fúngica da Expressão Gênica , Histona Acetiltransferases/genética , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Espécies Reativas de Oxigênio/metabolismo
16.
Int J Clin Pediatr Dent ; 16(1): 147-152, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37020764

RESUMO

Hartsfield syndrome is a rare and unique clinical combination of ectrodactyly and holoprosencephaly (HPE) with or without cleft lip and palate, as well as various additional characteristics. Although several genes responsible for HPE and ectrodactyly have been identified, the genetic origin of Hartsfield syndrome remains unknown, as there are few reports in the literature. The objective of this case report is to present dentofacial abnormalities in an 11-year-old boy with Hartsfield syndrome, who presented mental retardation, hearing loss, bilateral hand and foot ectrodactyly, HPE, and solitary median maxillary central incisor (SMMCI) besides 12 dental ageneses. How to cite this article: P Reis PM, Faber J, O Rosa JS, et al. Solitary Median Maxillary Central Incisor in Hartsfield Syndrome: A Case Report. Int J Clin Pediatr Dent 2023;16(1):147-152.

17.
Behav Brain Res ; 437: 114129, 2023 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-36179804

RESUMO

Evidence has demonstrated the hippocampal cholinergic system and the mammalian target of rapamycin (mTOR) participation during the memory formation of aversive events. This study assessed the role of these systems in the hippocampus for the extinction memory process by submitting male Wistar rats to fear-motivated step-down inhibitory avoidance (IA). The post-extinction session administration of the nicotinic and muscarinic cholinergic receptor antagonists, mecamylamine and scopolamine, respectively, both at doses of 2 µg/µl/side, and rapamycin, an mTOR inhibitor (0.02 µg/µl/side), into the CA1 region of the dorsal hippocampus, impaired the IA extinction memory. Furthermore, the nicotinic and muscarinic cholinergic receptor agonists, nicotine and muscarine, respectively, had a dose-dependent effect on the IA extinction memory when administered intra-CA1, immediately after the extinction session. Nicotine (0.6 µg/µl/side) and muscarine (0.02 µg/µl/side), respectively, had no effect, while the higher doses (6 and 2 µg/µl/side, respectively) impaired the IA extinction memory. Interestingly, the co-administration of muscarine at the lower dose blocked the impairment that was induced by rapamycin. This effect was not observed when nicotine at the lower dose was co-administered. These results have demonstrated the participation of the cholinergic receptors and mTOR in the hippocampus for IA extinction, and that the cholinergic agonists had a dose-dependent effect on the IA extinction memory. This study provides insights related to the behavioural aspects and the neurobiological properties underlying the early stage of fear-motivated IA extinction memory consolidation and suggests that there is hippocampal muscarinic receptor participation independent of mTOR in this memory process.


Assuntos
Aprendizagem da Esquiva , Extinção Psicológica , Medo , Hipocampo , Memória , Receptores Colinérgicos , Serina-Treonina Quinases TOR , Animais , Masculino , Ratos , Aprendizagem da Esquiva/fisiologia , Medo/fisiologia , Hipocampo/metabolismo , Muscarina/farmacologia , Antagonistas Muscarínicos/farmacologia , Nicotina/farmacologia , Ratos Wistar , Receptores Colinérgicos/metabolismo , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Extinção Psicológica/fisiologia , Memória/fisiologia
18.
Naunyn Schmiedebergs Arch Pharmacol ; 396(7): 1535-1545, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36790483

RESUMO

Morphine is among the most powerful analgesics and pain-relieving agents. However, its addictive properties limit their medical use because patients may be susceptible to abuse and reinstatement. Morphine addiction occurs because of dopamine release in the mesolimbic brain area, implying in an increase in oxidative stress. Ferulic acid (FA), a phenolic phytochemical found in a variety of foods, has been reported to exert antioxidant and neuroprotective effects; however, its low bioavailability makes its nano-encapsulated form a promising alternative. This study aimed to evaluate the protective effects of a novel nanosystem with FA on morphine reinstatement and the consequent molecular neuroadaptations and oxidative status in the mesolimbic region. Rats previously exposed to morphine in conditioned place preference (CPP) paradigm were treated with ferulic acid-loaded nanocapsules (FA-Nc) or nonencapsulated FA during morphine-preference extinction. Following the treatments, animals were re-exposed to morphine to induce the reinstatement. While morphine-preference extinction was comparable among all experimental groups, FA-Nc treatment prevented morphine reinstatement. In the dorsal striatum, while morphine exposure increased lipid peroxidation (LP) and reactive species (RS), FA-Nc decreased LP and FA decreased RS levels. Morphine exposure increased the dopaminergic markers (D1R, D3R, DAT) and ΔFosB immunoreactivity in the ventral striatum; however, FA-Nc treatment decreased D1R, D3R, and ΔFosB and increased D2R, DAT, and NRF2. In conclusion, FA-Nc treatment prevented the morphine reinstatement, promoted antioxidant activity, and modified the dopaminergic neurotransmission, NRF2, and ΔFosB, what may indicate a neuroprotective and antioxidant role of this nanoformulation.


Assuntos
Dopamina , Morfina , Ratos , Animais , Morfina/farmacologia , Fator 2 Relacionado a NF-E2 , Antioxidantes/farmacologia , Encéfalo
19.
Front Microbiol ; 14: 1291930, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38075857

RESUMO

Extracellular vesicle (EV) production by bacteria is an important mechanism for microbial communication and host-pathogen interaction. EVs of some bacterial species have been reported to contain nucleic acids. However, the role of small RNAs (sRNAs) packaged in EVs is poorly understood. Here, we report on the RNA cargo of EVs produced by the pig pathogen Actinobacillus pleuropneumoniae, the causal agent of porcine pleuropneumonia, a disease which causes substantial economic losses to the swine industry worldwide. The EVs produced by aerobically and anaerobically grown bacteria were only slightly different in size and distribution. Total cell and outer membrane protein profiles and lipid composition of A. pleuropneumoniae whole cell extracts and EVs were similar, although EVs contained rough lipopolysaccharide compared to the smooth form in whole cells. Approximately 50% of Galleria mellonella larvae died after the injection of EVs. RNAseq, RT-PCR, protection from nuclease degradation, and database searching identified previously described and 13 novel A. pleuropneumoniae sRNAs in EVs, some of which were enriched compared to whole cell content. We conclude that A. pleuropneumoniae EVs contain sRNAs, including those known to be involved in virulence, and some with homologs in other Pasteurellaceae and/or non-Pasteurellaceae. Further work will establish whether the novel sRNAs in A. pleuropneumoniae EVs play any role in pathogenesis.

20.
Pharmacol Biochem Behav ; 218: 173427, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35810923

RESUMO

In psychostimulant drug addiction, relapse is the most concerning outcome to be managed, considering there is no approved treatment for this neuropsychiatric condition. Here, we investigated the effects of the CBD treatment on the relapse behavior triggered by stress, after being submitted to the amphetamine (AMPH)-induced conditioned place preference (CPP) in rats. To elucidate the mechanisms of action underlying the CBD treatment, we evaluated the neuroadaptations on dopaminergic and endocannabinoid targets in the ventral striatum (VS) and ventral tegmental area (VTA) of the brain. Animals received d,l-AMPH (4 mg/kg, i.p.) or vehicle in the CPP paradigm for 8 days. Following the first CPP test, animals were treated with CBD (10 mg/kg, i.p.) or its vehicle for 5 days and subsequently submitted to forced swim stress protocol to induce AMPH-CPP relapse. Behavioral findings showed that CBD treatment prevented AMPH-reinstatement, also exerting anxiolytic activity. At the molecular level, in the VTA, CBD restored the CB1R levels decreased by AMPH-exposure, increased NAPE-PLD, and decreased FAAH levels. In the VS, the increase of D1R and D2R, as well as the decrease of DAT levels induced by AMPH were restored by CBD treatment. The current outcomes evidence a substantial preventive action of the CBD on the AMPH-reinstatement evoked by stress, also involving neuroadaptations in both dopaminergic and endocannabinoid systems in brain areas closely involved in the addiction. Although further studies are needed, these findings support the therapeutic potential of CBD in AMPH-relapse prevention.


Assuntos
Anfetamina , Canabidiol , Anfetamina/farmacologia , Animais , Canabidiol/farmacologia , Dopamina , Endocanabinoides/farmacologia , Ratos , Recidiva
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