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Obesity is a major cause of nonalcohol fatty liver disease (NAFLD), which is characterized by hepatic fibrosis, lipotoxicity, inflammation, and apoptosis. Previous studies have shown that an imbalance in the autonomic nervous system is closely related to the pathogenesis of NAFLD. In this study, we investigated the effects of pyridostigmine (PYR), a cholinesterase (AChE) inhibitor, on HFD-induced liver injury and explored the potential mechanisms involving mitochondrial damage and oxidative stress. A murine model of HFD-induced obesity was established using the C57BL/6 mice, and PYR (3 mg/kg/d) or placebo was administered for 20 weeks. PYR reduced the body weight and liver weight of the HFD-fed mice. Additionally, the serum levels of IL-6, TNF-α, cholesterol, and triglyceride were significantly lower in the PYR-treated versus the untreated mice, corresponding to a decrease in hepatic fibrosis, lipid accumulation, and apoptosis in the former. Furthermore, the mitochondrial morphology improved significantly in the PYR-treated group. Consistently, PYR upregulated ATP production and the mRNA level of the mitochondrial dynamic factors OPA1, Drp1 and Fis1, and the mitochondrial unfolded protein response (UPRmt) factors LONP1 and HSP60. Moreover, PYR treatment activated the Keap1/Nrf2 pathway and upregulated HO-1 and NQO-1, which mitigated oxidative injury as indicated by decreased 8-OHDG, MDA and H2 O2 levels, and increased SOD activity. Finally, PYR elevated acetylcholine (ACh) levels by inhibiting AChE, and upregulated the α7nAChR and M3AChR proteins in the HFD-fed mice. PYR alleviated obesity-induced hepatic injury in mice by mitigating mitochondrial damage and oxidative stress via α7nAChR and M3AChR.
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Doença Hepática Crônica Induzida por Substâncias e Drogas , Hepatopatia Gordurosa não Alcoólica , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Brometo de Piridostigmina/farmacologia , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Doença Hepática Crônica Induzida por Substâncias e Drogas/complicações , Doença Hepática Crônica Induzida por Substâncias e Drogas/metabolismo , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , Fígado/metabolismo , Estresse Oxidativo , Cirrose Hepática/metabolismo , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Dieta , Dieta Hiperlipídica/efeitos adversosRESUMO
Transposable elements (TEs) occupy nearly 40% of mammalian genomes and, whilst most are fragmentary and no longer capable of transposition, they can nevertheless contribute to cell function. TEs within genes transcribed by RNA polymerase II can be copied as parts of primary transcripts; however, their full contribution to mature transcript sequences remains unresolved. Here, using long and short read (LR and SR) RNA sequencing data, we show that 26% of coding and 65% of noncoding transcripts in human pluripotent stem cells (hPSCs) contain TE-derived sequences. Different TE families are incorporated into RNAs in unique patterns, with consequences to transcript structure and function. The presence of TE sequences within a transcript is correlated with TE-type specific changes in its subcellular distribution, alterations in steady-state levels and half-life, and differential association with RNA Binding Proteins (RBPs). We identify hPSC-specific incorporation of endogenous retroviruses (ERVs) and LINE:L1 into protein-coding mRNAs, which generate TE sequence-derived peptides. Finally, single cell RNA-seq reveals that hPSCs express ERV-containing transcripts, whilst differentiating subpopulations lack ERVs and express SINE and LINE-containing transcripts. Overall, our comprehensive analysis demonstrates that the incorporation of TE sequences into the RNAs of hPSCs is more widespread and has a greater impact than previously appreciated.
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Retrovirus Endógenos/genética , Elementos Nucleotídeos Longos e Dispersos/genética , Células-Tronco Pluripotentes/metabolismo , Transcriptoma , Linhagem Celular , Humanos , RNA não Traduzido/genética , Proteínas de Ligação a RNA/metabolismoRESUMO
A photoactivated gas detector operated at room temperature was microfabricated using a simple hydrothermal method. We report that the photoactivated gas detector can detect toluene using a UV illumination of 2 µW/cm². By ultraviolet (UV) illumination, gas detectors sense toluene at room temperature without heating. A significant enhancement of detector sensitivity is achieved because of the high surface-area-to-volume ratio of the morphology of the coral-like ZnO nanorods arrays (NRAs) and the increased number of photo-induced oxygen ions under UV illumination. The corresponding sensitivity (ΔR/R0) of the detector based on coral-like ZnO NRAs is enhanced by approximately 1022% compared to that of thin-film detectors. The proposed detector greatly extends the dynamic range of detection of metal-oxide-based detectors for gas sensing applications. We report the first-ever detection of toluene with a novel coral-like NRAs gas detector at room temperature. A sensing mechanism model is also proposed to explain the sensing responses of gas detectors based on coral-like ZnO NRAs.
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PURPOSE: Gastro-esophageal reflux disease is common in patients with type 2 diabetes. A common treatment is the co-administration of proton-pump inhibitors (PPIs) and metformin. To date, however, the effects of co-administration of PPIs, which inhibit organic cation transporter (OCT) activity, on the action of metformin (a well-known substrate of OCTs) have not been clearly demonstrated. METHODS: This was a randomized, double-blind, two-way crossover, placebo-controlled trial. Healthy male volunteers (n = 20) received metformin (single dose 1,000 mg on day 1 and single dose 750 mg on day 2, with a 12-h interval) co-administered with placebo or with lansoprazole (30 mg). Plasma concentrations of metformin were measured up to 24 h after the second dose. The glucose-lowering effects of metformin were evaluated by the oral glucose tolerance test before and after each single dose of metformin within the 2-day period. RESULTS: Lansoprazole increased the mean metformin maximum plasma concentration and area under the plasma concentration-time curve from zero to 24 h after the second dosing by 15 and 17 %, respectively (P < 0.05). Moreover, lansoprazole prolonged the metformin elimination half-life from 3.9 to 4.5 h and decreased its renal clearance by 13 % (P < 0.05). However, lansoprazole had no effect on the maximum glucose level and the area under the serum glucose concentration-time curve of metformin. CONCLUSIONS: Collectively, we found a modest pharmacokinetic drug interaction between lansoprazole and metformin, which suggests that the concomitant use of these drugs should be appropriately monitored. Further studies are warranted to assess changes in metformin pharmacokinetics in patients with diabetes receiving long-term lansoprazole therapy.
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Antiulcerosos/farmacologia , Hipoglicemiantes/farmacocinética , Lansoprazol/farmacologia , Metformina/farmacocinética , Proteínas de Transporte de Cátions Orgânicos/antagonistas & inibidores , Inibidores da Bomba de Prótons/farmacologia , Adulto , Glicemia/análise , Estudos Cross-Over , Método Duplo-Cego , Interações Medicamentosas , Teste de Tolerância a Glucose , Voluntários Saudáveis , Humanos , Hipoglicemiantes/sangue , Hipoglicemiantes/farmacologia , Hipoglicemiantes/urina , Masculino , Metformina/sangue , Metformina/farmacologia , Metformina/urinaRESUMO
BACKGROUND: Cardiometabolic index (CMI) is a novel marker of diabetes mellitus. However, few studies have examined its association with gestational diabetes mellitus (GDM) risk. This study aimed to explore the association between CMI and GDM risk among pregnant women in the United States. METHODS: We performed a cross-sectional study utilizing data recorded in the National Health and Nutrition Examination Survey database from 1999 to 2018. Univariate and multivariate logistic regression, restricted cubic splines (RCS), sensitivity, and subgroup analyses were performed to clarify the relationship between CMI and GDM risk. RESULTS: A total of 710 pregnant women were recruited, among whom 113 were diagnosed with GDM based on established criteria. This population showed a significant association between a higher CMI value and GDM (odds ratio: 1.75, 95% confidence interval: 1.03-2.99, P = 0.038). RCS regression analysis identified a linear relationship between CMI and GDM (P-value < 0.001, P-nonlinear = 0.702). Sensitivity analysis further confirmed the validity of this relationship. Subgroup analysis indicated a positive association between CMI and GDM among women who drink or smoke and Mexican Americans. CONCLUSION: This study demonstrates a significant positive association between CMI and GDM risk, suggesting that a higher CMI predicts GDM incidence during pregnancy. Further research is required to investigate the CMI index as an early predictor of GDM.
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Metabolic reprogramming is a hallmark of cancer and is crucial for cancer progression, making it an attractive therapeutic target. Understanding the role of metabolic reprogramming in cancer initiation could help identify prevention strategies. To address this, we investigated metabolism during acinar-to-ductal metaplasia (ADM), the first step of pancreatic carcinogenesis. Glycolytic markers were elevated in ADM lesions compared with normal tissue from human samples. Comprehensive metabolic assessment in three mouse models with pancreas-specific activation of KRAS, PI3K, or MEK1 using Seahorse measurements, nuclear magnetic resonance metabolome analysis, mass spectrometry, isotope tracing, and RNA sequencing analysis revealed a switch from oxidative phosphorylation to glycolysis in ADM. Blocking the metabolic switch attenuated ADM formation. Furthermore, mitochondrial metabolism was required for de novo synthesis of serine and glutathione (GSH) but not for ATP production. MYC mediated the increase in GSH intermediates in ADM, and inhibition of GSH synthesis suppressed ADM development. This study thus identifies metabolic changes and vulnerabilities in the early stages of pancreatic carcinogenesis. Significance: Metabolic reprogramming from oxidative phosphorylation to glycolysis mediated by MYC plays a crucial role in the development of pancreatic cancer, revealing a mechanism driving tumorigenesis and potential therapeutic targets. See related commentary by Storz, p. 2225.
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Metaplasia , Neoplasias Pancreáticas , Animais , Humanos , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/genética , Camundongos , Metaplasia/metabolismo , Metaplasia/patologia , Glicólise , Carcinogênese/metabolismo , Células Acinares/metabolismo , Células Acinares/patologia , Fosforilação Oxidativa , Glutationa/metabolismo , Reprogramação Celular , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Masculino , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Reprogramação MetabólicaRESUMO
We are grateful to the authors for providing additional data to demonstrate the presence of domestic cat hepadnavirus in lymphoma tissues [...].
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Hepadnaviridae , Linfoma , Gatos , Animais , Linfoma/veterináriaRESUMO
Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic and lethal disease. Gasdermins are primarily associated with necrosis via membrane permeabilization and pyroptosis, a lytic pro-inflammatory type of cell death. In this study, GSDMC upregulation during PDAC progression is reported. GSDMC directly induces genes related to stemness, EMT, and immune evasion. Targeting Gsdmc in murine PDAC models reprograms the immunosuppressive tumor microenvironment, rescuing the recruitment of anti-tumor immune cells through CXCL9. This not only results in diminished tumor initiation, growth and metastasis, but also enhances the response to KRASG12D inhibition and PD-1 checkpoint blockade, respectively. Mechanistically, it is discovered that ADAM17 cleaves GSDMC, releasing nuclear fragments binding to promoter regions of stemness, metastasis, and immune evasion-related genes. Pharmacological inhibition of GSDMC cleavage or prevention of its nuclear translocation is equally effective in suppressing GSDMC's downstream targets and inhibiting PDAC progression. The findings establish GSDMC as a potential therapeutic target for enhancing treatment response in this deadly disease.
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The aim of this study is to investigate a food effect on the single-dose pharmacokinetics and tolerability of clinofibrate tablets in 12 Chinese healthy volunteers. The authors evaluated the effect of being under a fasting or fed state at the time of drug intake on the single-dose of clinofibrate 400 mg tablets in a randomized, balanced, single-dose, two-treatment (fed and fasting), two-period, two-sequence study design with a 7-day washout period. The end points were the maximum plasma drug concentration (Cmax) and areas under the plasma-concentration curve (AUC) for 72 hours exposure (AUC0-72) and total exposure (AUC0-∞). All participants completed the whole study without side effects being observed. The Cmax mean of clinofibrate glucuronides and parent clinofibrate were 21.91, 17.85 µ/ml for the fasting state and 13.14, 11.25 µ/ml for the fed state, respectively. The AUC0-72 and AUC0-∞ of clinofibrate glucuronides and parent clinofibrate were 381.60, 307.07 µ/ ml and 404.55, 342.24 µ/ml for the fasting state and 379.02, 321.14 µ/ml and 432.24, 351.80 µ/ml for the fed state. The authors showed that food intake was associated with a significant decrease in Cmax, but no significant change in AUC values.
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Interações Alimento-Droga , Fenoxiacetatos/farmacocinética , Adulto , Área Sob a Curva , Estudos Cross-Over , Feminino , Humanos , Masculino , Fenoxiacetatos/efeitos adversos , ComprimidosRESUMO
Ectopic ATP synthase complex (eATP synthase), located on cancer cell surface, has been reported to possess catalytic activity that facilitates the generation of ATP in the extracellular environment to establish a suitable microenvironment and to be a potential target for cancer therapy. However, the mechanism of intracellular ATP synthase complex transport remains unclear. Using a combination of spatial proteomics, interaction proteomics, and transcriptomics analyses, we find ATP synthase complex is first assembled in the mitochondria and subsequently delivered to the cell surface along the microtubule via the interplay of dynamin-related protein 1 (DRP1) and kinesin family member 5B (KIF5B). We further demonstrate that the mitochondrial membrane fuses to the plasma membrane in turn to anchor ATP syntheses on the cell surface using super-resolution imaging and real-time fusion assay in live cells. Our results provide a blueprint of eATP synthase trafficking and contribute to the understanding of the dynamics of tumor progression.
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Mitocôndrias , Neoplasias , Humanos , Mitocôndrias/metabolismo , Membrana Celular/metabolismo , Membranas Mitocondriais/metabolismo , Neoplasias/metabolismo , Trifosfato de Adenosina/metabolismo , Microambiente TumoralRESUMO
We write to comment on Piewbang C et al [...].
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Doenças do Gato , Hepadnaviridae , Linfoma , Animais , Gatos , Linfoma/veterináriaRESUMO
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a profoundly aggressive and fatal cancer. One of the key factors defining its aggressiveness and resilience against chemotherapy is the existence of cancer stem cells (CSCs). The important task of discovering upstream regulators of stemness that are amenable for targeting in PDAC is essential for the advancement of more potent therapeutic approaches. In this study, we sought to elucidate the function of the nuclear receptor subfamily 5, group A, member 2 (NR5A2) in the context of pancreatic CSCs. METHODS: We modeled human PDAC using primary PDAC cells and CSC-enriched sphere cultures. NR5A2 was genetically silenced or inhibited with Cpd3. Assays included RNA-seq, sphere/colony formation, cell viability/toxicity, real-time PCR, western blot, immunofluorescence, ChIP, CUT&Tag, XF Analysis, lactate production, and in vivo tumorigenicity assays. PDAC models from 18 patients were treated with Cpd3-loaded nanocarriers. RESULTS: Our findings demonstrate that NR5A2 plays a dual role in PDAC. In differentiated cancer cells, NR5A2 promotes cell proliferation by inhibiting CDKN1A. On the other hand, in the CSC population, NR5A2 enhances stemness by upregulating SOX2 through direct binding to its promotor/enhancer region. Additionally, NR5A2 suppresses MYC, leading to the activation of the mitochondrial biogenesis factor PPARGC1A and a shift in metabolism towards oxidative phosphorylation, which is a crucial feature of stemness in PDAC. Importantly, our study shows that the specific NR5A2 inhibitor, Cpd3, sensitizes a significant fraction of PDAC models derived from 18 patients to standard chemotherapy. This treatment approach results in durable remissions and long-term survival. Furthermore, we demonstrate that the expression levels of NR5A2/SOX2 can predict the response to treatment. CONCLUSIONS: The findings of our study highlight the cell context-dependent effects of NR5A2 in PDAC. We have identified a novel pharmacological strategy to modulate SOX2 and MYC levels, which disrupts stemness and prevents relapse in this deadly disease. These insights provide valuable information for the development of targeted therapies for PDAC, offering new hope for improved patient outcomes. A Schematic illustration of the role of NR5A2 in cancer stem cells versus differentiated cancer cells, along with the action of the NR5A2 inhibitor Cpd3. B Overall survival of tumor-bearing mice following allocated treatment. A total of 18 PDX models were treated using a 2 x 1 x 1 approach (two animals per model per treatment); n=36 per group (illustration created with biorender.com ).
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Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Animais , Camundongos , Transdução de Sinais , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Linhagem Celular Tumoral , Recidiva Local de Neoplasia/patologia , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Células-Tronco Neoplásicas/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Neoplasias PancreáticasRESUMO
Subsequently to the publication of the above article, an interested reader drew to the authors' attention that the OGD + HYSA and OGD + HYSA + AKBA plots in Fig. 5B on p. 1507 appeared to share a similar patterning with respect to many of the data points. The authors have re-examined their original data and realize that they made inadvertent errors during the assembly of this figure. The FCS files were read and analyzed by FlowJo cell analysis software. The authors have carefully examined the raw data (fcs files), and have identified the errors that occurred when applying the setting to all files and saving the resulting fluorescence data to dot-plot graphs. The corrected version of Fig. 5, showing the correct flow cytometric analysis data in Fig. 5B and a re-evaluation of the quantification of the data in the associated bar chart, is shown on the next page. Note that the errors made during the assembly of this figure did not affect the major conclusions reported in the paper. All the authors have agreed to this Corrigendum, and thank the Editor of International Journal of Molecular Medicine for allowing them the opportunity to publish this. The authors regret these errors went unnoticed prior to the publication of the paper, and apologize to the readership for any confusion that this may have caused. [the original article was published in International Journal of Molecular Medicine 37: 1501-1510, 2016; DOI: 10.3892/ijmm.2016.2571].
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Chronic hepatitis and hepatocellular carcinoma (HCC) caused by the hepadnavirus hepatitis B virus (HBV) are significant causes of human mortality. A hepatitis-B-like virus infecting cats, domestic cat hepadnavirus (DCH), was reported in 2018. DCH DNA is hepatotropic and detectable in feline blood or serum (3.2 to 12.3%). Detection of HBV DNA has been reported in sera from 10% of free-roaming dogs in Brazil, whereas 6.3% of sera from dogs in Italy tested positive for DCH DNA by real-time quantitative PCR (qPCR). If DCH, HBV, or another hepadnavirus is hepatotropic in dogs, a role for such a virus in the etiology of canine idiopathic chronic hepatitis (CH) or HCC warrants investigation. This study investigated whether DCH DNA could be detected via qPCR in blood from dogs in Hong Kong and also whether liver biopsies from dogs with confirmed idiopathic CH or HCC contained hepadnaviral DNA using two panhepadnavirus conventional PCRs (cPCR) and a DCH-specific cPCR. DCH DNA was amplified from 2 of 501 (0.4%) canine whole-blood DNA samples. A second sample taken 6 or 7 months later from each dog tested negative in DCH qPCR. DNA extracted from 101 liver biopsies from dogs in Hong Kong or the USA, diagnosed by board-certified pathologists as idiopathic CH (n = 47) or HCC (n = 54), tested negative for DCH DNA and also tested negative using panhepadnavirus cPCRs. This study confirms that DCH DNA can be detected in canine blood by qPCR, although at a much lower prevalence than that reported previously. We identified no evidence to support a pathogenic role for a hepadnavirus in canine idiopathic CH or HCC.
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Carcinoma Hepatocelular , Hepadnaviridae , Neoplasias Hepáticas , Animais , Biópsia , Carcinoma Hepatocelular/veterinária , Gatos , DNA Viral/genética , Cães , Hepadnaviridae/genética , Vírus da Hepatite B/genética , Hepatite Crônica , Hong Kong , HumanosRESUMO
Background: Carbapenems are considered the last line of defence against bacterial infections, but their high consumption and the resulting antibacterial resistance are an increasing global concern. In this context, the Chinese health authority issued an expert consensus on the clinical applications of carbapenems. However, the long- and short-term effects of the expert consensus on carbapenem use are not clear. Methods: This study was conducted in Shaanxi, a northwest province of China. We collected all available carbapenem procurement data between January 2017 and December 2020 from the Provincial Drug Centralized Bidding Procurement System. A quasi-experimental interrupted time series analysis was used to evaluate the longitudinal effectiveness of expert consensus by measuring the change in the Defined Daily Dosesper 1,000 inhabitants per day (DID), the percentage of carbapenem expenditures to total antimicrobial expenditure, the total carbapenem expenditure, and the defined daily cost (DDDc). We used Stata SE version 15.0 for data analysis, and p < 0.05 was considered statistically significant. Results: After the distribution of the expert consensus, the level (p = 0.769) and trend (p = 0.184) of DID decreased, but the differences were not statistically significant. The percentage of carbapenem expenditures to total antimicrobial expenditure decreased abruptly (p < 0.001) after the intervention, but the long-term trend was still upward. There was no statistically significant relationship between the release of the expert consensus and carbapenem expenditure in the long term, but there was a decreasing trend (p = 0.032). However, the expert consensus had a positive impact on the economic burden of carbapenem usage in patients, as the level (p < 0.001), and trend (p = 0.003) of DDDc significantly decreased. Conclusion: The long-term effects of the distribution of the expert consensus on the use and expenditure of carbapenems in public health institutions in Shaanxi Province were not optimal. It is time to set up more administrative measures and scientific supervision to establish a specific index to limit the application of carbapenems.
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This study develops an operationally easy, efficient, and general 1,2-trans beta-selective glycosylation reaction that proceeds in the absence of a C2 acyl function. This process employs chemically stable thioglycosyl donors and low substrate concentrations to achieve excellent beta-selectivities in glycosylation reactions. This method is widely applicable to a range of glycosyl substrates irrespective of their structures and hydroxyl-protecting functions. This low-concentration 1,2-trans beta-selective glycosylation in carbohydrate chemistry removes the restriction of using highly reactive thioglycosides to construct 1,2-trans beta-glycosidic bonds. This is beneficial to the design of new strategies for oligosaccharide synthesis, as illustrated in the preparation of the biologically relevant beta-(1-->6)-glucan trisaccharide, beta-linked Gb(3) and isoGb(3) derivatives.
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The aim of the present study was to assess whether dietary advanced glycation end products (AGEs) induce testicular dysfunction. Using a BALB/c mouse model, AGE intake and serum levels were found to increase in AGE diet-treated mice relative to the controls. Histopathological damage was detected in the testes and epididymides of the AGE diet-induced mice. The total number of epididymal sperm decreased, and increased abnormal sperm rate was found in the mice. Moreover, the mice testes showed an increased level of the receptor for AGEs (RAGE) and malondialdehyde (MDA). Using a Sprague-Dawley rat model, AGE diet-induced rats showed 3- to 4-fold higher AGE intake than the controls. In these rats, higher serum and sperm MDA levels, decreased epididymal sperm numbers, and increased abnormal sperm rates were also observed. Silymarin, a natural AGE inhibitor, was found to restore these AGE-induced phenomena. Concluding from the above findings, dietary AGEs may promote testicular dysfunction.
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Epididimo/citologia , Produtos Finais de Glicação Avançada/metabolismo , Espermatogênese , Espermatozoides/citologia , Testículo/citologia , Animais , Epididimo/metabolismo , Masculino , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Ratos , Ratos Sprague-Dawley , Receptor para Produtos Finais de Glicação Avançada/genética , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Contagem de Espermatozoides , Espermatozoides/metabolismo , Testículo/metabolismoRESUMO
The phycosphere of phytoplankton harbors a diversity of microbes that can potentially interact with the host phytoplankton cells. In spite of increasing reports regarding the interactions between some model phytoplankton and bacteria, there remain many unknowns regarding interactions between the dinoflagellate Akashiwo sanguinea and its phycosphere bacteria. Here we used both cultivation and metagenomic sequencing methods to investigate the microbial community composition in A. sanguinea batch cultures under various growth conditions. The microbial community dynamics under different growth stages and nutrient (nitrogen and iron) depletion scenarios were determined by Illumina MiSeq sequencing of 16S rRNA gene amplicons. Rhodobacteraceae, Alteromonadaceae and Flavobacteriaceae were the main bacterial families and varied significantly under different states of the host A. sanguinea. Selective fluorescence in situ hybridization was also performed to label Rhodobacterales and Alteromonas clade bacteria to confirm their attachment to A. sanguinea cells under confocal laser scanning microscopy. Plate streaking protocol isolated 19 bacterial strains from A. sanguinea cultures, identified through 16S rRNA analysis. Most culturable strains (11 of 19) belonged to Rhodobacteraceae consistent with Illumina MiSeq sequencing data. The possible interaction pathway between these epibiotic bacteria and A. sanguinea in the phycosphere is also discussed.
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Bactérias/isolamento & purificação , Dinoflagellida/crescimento & desenvolvimento , Dinoflagellida/microbiologia , Bactérias/classificação , Bactérias/genética , Proliferação Nociva de Algas , Sequenciamento de Nucleotídeos em Larga Escala , Hibridização in Situ Fluorescente , Microbiota , Filogenia , Fitoplâncton/microbiologiaRESUMO
Inexpensive and readily available sulfonic acids, p-toluenesulfonic acid, and sulfuric acid are versatile and efficient catalysts for the peracetylation of a broad spectrum of carbohydrate substrates in good yield and in a practical time frame. Three appealing features in sulfonic acid-catalyzed acetylation of free sugars were explored including (1) suppression of furanosyl acetate formation for D-galactose and L-fucose; (2) high yielding chemoselective acetylation of sialic acid under appropriate conditions; and (3) peracetylation of amino sugars with different amino protecting functions. Simple one-pot two step acetylation-thioglycosidation methods for the expeditious synthesis of p-tolyl per-O-acetyl thioglycosides were also delineated.