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1.
Toxins (Basel) ; 16(6)2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38922174

RESUMO

Despite the fact that the first red tide reported on the coasts of the Iberian Peninsula was due to Lingulodinium polyedra, knowledge about their frequency and, particularly, about the environmental conditions contributing to bloom initiation is still scarce. For this reason, L. polyedra bloom episodes were observed and studied in three Galician rias during the summer season based on the 1993-2008 record database period; additionally, samples were collected in summer 2008. Proliferations of L. polyedra occurred in the rias of Ares and Barqueiro in June and August, respectively, while in the Ria of Coruña, they persisted from the end of June to early September. Red tides developed when the surface temperature reached 17 °C, with "seasonal thermal window" conditions, and when salinities were ≥30, i.e., an "optimal salinity window"; when these parameters were lower than these thresholds, cyst germination decreased. A cyst transport mechanism from sediments to the surface must also exist; this mechanism was found to be natural (tidal currents) in the ria of Barqueiro or anthropogenic (dredging) in the rias of Ares and Coruña. Surface temperatures during summer were usually favorable for cyst germination (85 to 100%) during the 1993-2008 period; however, water temperatures below 10 m depth only rarely reached the 17 °C threshold (2 to 18%). During this 16-year period, dredging activities could explain 71% (Coruña) and 44% (Ares) of the recorded bloom events. When a bloom episode developed in early summer, favorable conditions did not lead to a new red tide, probably due to the lag period required by cysts for germination. Moreover, blooms did not develop when high densities of diatoms (>1,000,000 cells·L-1) remained in the water column as a result of summer upwelling pulses occurring in specific years. The temperature-sediment disturbance pattern found in this study provides a useful tool for the prevention of eventual risks resulting from red tides of this dinoflagellate.


Assuntos
Dinoflagellida , Proliferação Nociva de Algas , Temperatura , Dinoflagellida/crescimento & desenvolvimento , Espanha , Estações do Ano , Monitoramento Ambiental , Água do Mar , Sedimentos Geológicos , Salinidade
2.
Psychophysiology ; 61(6): e14537, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38333910

RESUMO

Savoring is a positive emotion up-regulation technique that can increase electrocortical and self-reported valence and arousal to positive and neutral pictures, with effects persisting to increase response to the same stimuli when encountered later. Outside of the lab, emotion regulation techniques that persist to affect not just encounters with the same stimuli but also encounters with similar, but previously unencountered stimuli should save individuals time and effort. Here, we used event-related potentials and picture ratings to test whether savoring would generalize to similar, but previously unseen positive pictures. To this end, 89 participants (56 female; M age = 18.96 years, SD = 1.87) were asked to savor positive pictures from one category (e.g., happy people) and to view positive pictures from another category (e.g., cute animals), as well as to view neutral pictures (e.g., plants). In a subsequent passive picture viewing task, participants viewed novel pictures from all three categories (i.e., happy people, cute animals, plants). In the first task, savoring was effective for pictures of animals throughout picture presentation, but only for pictures of people during the later part of picture presentation. In the second task, savoring generalized to novel pictures of animals, though this was only evident in the early portion of picture processing (and for self-reported ratings). Therefore, savoring holds promise as a useful technique for increasing positive emotion in everyday life, though more work is needed to understand whether effects may vary depending on different types of picture content.


Assuntos
Eletroencefalografia , Potenciais Evocados , Humanos , Feminino , Masculino , Adolescente , Adulto Jovem , Potenciais Evocados/fisiologia , Adulto , Regulação Emocional/fisiologia , Generalização Psicológica/fisiologia , Emoções/fisiologia , Nível de Alerta/fisiologia , Reconhecimento Visual de Modelos/fisiologia
6.
Pediatr Surg Int ; 39(1): 80, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36631569

RESUMO

PURPOSE: Nowadays, the standard therapy for patients with short bowel syndrome is parenteral nutrition (PN). Various growth factors have been tested to achieve weaning from prolonged PN administration. We evaluated the effect of hepatocyte growth factor (HGF) on structural intestinal adaptation and cell proliferation in a rat model of SBS. METHODS: Thirty Sprague-Dawley rats were divided into three groups; group A rats (sham) underwent bowel transection, group B rats underwent a 75% bowel resection, and group C rats underwent the same procedure but were treated postoperatively with HGF. Histopathologic parameters of intestinal adaptation were determined, while microarray and rt-PCR analyses of ileal RNA were also performed. RESULTS: Treatment with HGF resulted in significant increase in body weight, while the jejunal and ileal villus height and crypt depth were increased in HGF rats (36%, p < 0.05 and 27%, p < 0.05 respectively). Enterocyte proliferation was also significantly increased in HGF rats (21% p < 0.05). Microarray and quantitative rt-PCR analyses showed that the genes hgfac, rac 1, cdc42, and akt 1 were more than twofold up-regulated after HGF treatment. CONCLUSION: HGF emerges as a growth factor that enhances intestinal adaptation. The future use of HGF may potentially reduce the requirement for PN in SBS patients.


Assuntos
Adaptação Fisiológica , Fator de Crescimento de Hepatócito , Síndrome do Intestino Curto , Animais , Ratos , Modelos Animais de Doenças , Fator de Crescimento de Hepatócito/farmacologia , Fator de Crescimento de Hepatócito/uso terapêutico , Mucosa Intestinal/metabolismo , Intestinos/patologia , Modelos Teóricos , Ratos Sprague-Dawley , Síndrome do Intestino Curto/tratamento farmacológico , Síndrome do Intestino Curto/metabolismo
7.
Genes (Basel) ; 13(12)2022 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-36553594

RESUMO

Background: Chemoresistance is a significant barrier to combating head and neck cancer, and decoding this resistance can widen the therapeutic application of such chemotherapeutic drugs. This systematic review and meta-analysis explores the influence of microRNA (miRNA) expressions on chemoresistance in head and neck cancers (HNC). The objective is to evaluate the theragnostic effects of microRNA expressions on chemoresistance in HNC patients and investigate the utility of miRNAs as biomarkers and avenues for new therapeutic targets. Methods: We performed a comprehensive bibliographic search that included the SCOPUS, PubMed, and Science Direct bibliographic databases. These searches conformed to a predefined set of search strategies. Following the PRISMA guidelines, inclusion and exclusion criteria were framed upon completing the literature search. The data items extracted were tabulated and collated in MS Excel. This spreadsheet was used to determine the effect size estimation for the theragnostic effects of miRNA expressions on chemoresistance in HNC, the hazard ratio (HR), and 95% confidence intervals (95% CI). The comprehensive meta-analysis was performed using the random effects model. Heterogeneity among the data collected was assessed using the Q test, Tau2, I2, and Z measures. Publication bias of the included studies was checked using the Egger's bias indicator test, Orwin and classic fail-safe N test, Begg and Mazumdar rank collection test, and Duval and Tweedie's trim and fill methods. Results: After collating the data from 23 studies, dysregulation of 34 miRNAs was observed in 2189 people. These data were gathered from 23 studies. Out of the 34 miRNAs considered, 22 were up-regulated, while 12 were down-regulated. The TaqMan transcription kits were the most used miRNA profiling platform, and miR-200c was seen to have a mixed dysregulation. We measured the overall pooled effect estimate of HR to be 1.516 for the various analyzed miRNA at a 95% confidence interval of 1.303-1.765, with a significant p-value. The null hypothesis test's Z value was 5.377, and the p-value was correspondingly noted to be less than 0.0001. This outcome indicates that the risk of death is determined to be higher in up-regulated groups than in down-regulated groups. Among the 34 miRNAs that were investigated, seven miRNAs were associated with an improved prognosis, especially with the overexpression of these seven miRNAs (miR15b-5p, miR-548b, miR-519d, miR-1278, miR-145, miR-200c, Hsa- miR139-3p). Discussion: The findings reveal that intricate relationships between miRNAs' expression and chemotherapeutic resistance in HNC are more likely to exist and can be potential therapeutic targets. This review suggests the involvement of specific miRNAs as predictors of chemoresistance and sensitivity in HNC. The examination of the current study results illustrates the significance of miRNA expression as a theragnostic biomarker in medical oncology.


Assuntos
Neoplasias de Cabeça e Pescoço , MicroRNAs , Humanos , Biomarcadores Tumorais/genética , MicroRNAs/genética , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/genética , Prognóstico
8.
Vet Res Forum ; 13(3): 349-356, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36320308

RESUMO

Ovine pulmonary adenocarcinoma (OPA) is a model of human lung cancer and fatal viral disease that causes neoplasia in sheep respiratory cells. In the current study, 986 lung samples was inspected in the slaughterhouse, and finally twenty OPA lung organs were clinically diagnosed and five healthy lung organs were assigned as the control sample. Three SSCP patterns were detected for the affected lungs animals in comparison with the healthy lungs. In addition, sequencing results indicated three different single point mutations in exon 4 of TP53 within infected lungs, whereas no mutations were observed in exon 9 of this gene. Real-time PCR results showed up-regulation of the TP53 gene in all the infected lung cells compared to healthy cells. There was significant correlation between the mutations in exon 4 and OPAand can be used as a useful tool in determining the mechanism of lung cancer.

9.
Eur J Pharmacol ; 932: 175230, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36027983

RESUMO

Cancer is one of the most common and dreaded diseases affecting the vastness of society. Unfortunately, still some people die especially when cancer is not diagnosed and thus caught early enough. On the other hand, using available chemo- or radiotherapy may result in serious side effects. Therefore, cancer-specific medications seem to be the most desired and safe therapy. Knowing that some cancers are characterized by overexpression of specific receptors on the cell surface, target-mediated drugs could serve as a unique and effective form of therapy. In line with this, recently dopaminergic receptors were presented important in cancer therapy as several dopaminergic ligands revealed their efficacy in tumor growth reduction as well as in apoptosis mediation. Unfortunately, the indication of whether DA receptor agonists or antagonists are the best choices in cancer treatment is quite difficult, since both of them may exert either pro- or anticancer effects. In this review, we analyze the therapeutic efficacy of compounds, both of exogenous and endogenous origin, targeting dopaminergic receptor-expressing cancers.


Assuntos
Antagonistas de Dopamina , Neoplasias , Dopamina , Agonistas de Dopamina , Humanos , Ligantes , Neoplasias/tratamento farmacológico , Receptores Dopaminérgicos , Receptores de Dopamina D1/agonistas
10.
Front Cell Infect Microbiol ; 12: 935806, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35846769

RESUMO

Chronic inflammation is known to contribute to various human cancers. Porphyromonas gingivalis (P. gingivalis), is a gram-negative oral keystone pathogen that may cause severe periodontitis and expresses several virulence factors to affect the host immune system. Periodontitis is a chronic infectious disease that while progression, may cause loss of attachment and destruction of the tooth supporting tissues. Prostate cancer is one of the most common malignancies in men. Increasing evidence links periodontitis with prostate cancer, however the mechanisms explaining this relationship remain unclear. The aim of this study was to investigate the expression and signaling pathway of programmed death ligand 1 (PD-L1) in a prostate cancer cell line after infection with P. gingivalis and stimulation with P. gingivalis components to reveal the mechanism of tumor-induced immune evasion associated with bacterial infection in the tumor environment. Prostate cancer cells were infected with different concentrations of viable P. gingivalis and treated with different concentrations of heat-killed P. gingivalis and P. gingivalis cell components, including the total membrane fraction, inner membrane fraction, outer membrane fraction, cytosolic fraction and peptidoglycan (PGN). Chemical inhibitors were used to block different important molecules of signaling pathways to assess the participating signal transduction mechanisms. PD-L1 expression was detected by Western blot after 24 h of infection. PD-L1 was demonstrated to be upregulated in prostate cancer cells after infection with viable and with heat-killed P. gingivalis membrane fractions. Also isolated PGN induced PD-L1 up-regulation. The upregulation was mediated by the NOD1/NOD2 signaling pathway. No upregulation could be detected after treatment of the cells with P. gingivalis lipopolysaccharide (LPS). These results indicate, that chronic inflammatory disease can contribute to tumor immune evasion by modifying the tumor microenvironment. Thus, chronic infection possibly plays an essential role in the immune response and may promote the development and progression of prostate cancer.


Assuntos
Periodontite , Neoplasias da Próstata , Antígeno B7-H1/metabolismo , Humanos , Masculino , Periodontite/microbiologia , Porphyromonas gingivalis , Microambiente Tumoral , Regulação para Cima
12.
Rev. bras. cir. cardiovasc ; Rev. bras. cir. cardiovasc;37(3): 370-379, May-June 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1376533

RESUMO

ABSTRACT Introduction: The objective of this study is to investigate the protective mechanism of dexmedetomidine (Dex) in myocardial ischemia/reperfusion (MIR)-induced acute lung injury (ALI) of diabetic rats by inhibiting hypoxia-inducible factor-1α (HIF-1α). Methods: Initially, healthy male Sprague Dawley rats were treated with streptozocin to induce diabetes. Then, three weeks after the induction, Dex or lentiviral vector (LV)-HIF-1α was injected into the rats 30 minutes prior to the MIR modeling. After four weeks, lung tissues were harvested for pathological changes observation and the wet/dry weight (W/D) ratio determination. Afterwards, oxidative stress indicators and pro-inflammatory factors were measured. In addition, HIF-1α expression was assessed by immunohistochemistry and western blot analysis. Results: Dex could suppress inflammatory cell infiltration, improve lung tissue structure, reduce pathological score and the W/D ratio, and block oxidative stress and inflammatory response in MIR-induced ALI of diabetic rats. Besides, Dex could also inhibit HIF-1α expression. Moreover, Dex + LV-HIF-1α reversed the protective role of Dex on diabetic MIR-induced ALI. Conclusion: Our study has made it clear that Dex inhibited the upregulation of HIF-1α in diabetic MIR-induced ALI, and thus protect lung functions by quenching the accumulation of oxygen radical and reducing lung inflammatory response.

13.
Avicenna J Med Biotechnol ; 14(1): 89-94, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35509367

RESUMO

Background: Prostate Cancer (PCa) is the major reason for the high mortality rates among men worldwide. In fact, current therapeutic approaches are not successful. It appears that discovering more effective methods considering several parameters such as availability, low cost, and no toxicity to normal cells is one of the biggest challenges for interested researchers. Green tea (extracted from the plant Camellia sinensis) with high level of polyphenolic compounds and as the most globally consumed beverage has attracted considerable interest. MicroRNAs (or miRNAs) were considered as novel tools in cancer therapy which modulate various biological events in cell by regulation of gene expression. The aim of the current study was to evaluate the antitumor activity of green tea in LNCaP cells through up-regulation of miR-181a expression. Methods: First, LNCaP cells were cultured and by using quantitative real time PCR (qRT-PCR) and western blot methods, the expression levels of Bax and BCL2 were analyzed. Next, a 3D cell culture model was applied to evaluate the expression of miRNA-181a in LNCaP cells. Results: It was shown that green tea induced cellular apoptosis. The high number of apoptotic nuclei was also shown by using DAPI staining. The inhibition of tumor growth was revealed by analyzing the size and number of spheroids. Also, up-regulation of miR-181a expression in LNCaP cells was revealed after treatment with green tea. Conclusion: Our results are helpful to design antitumor regimens based on consumption of green tea through up-regulation of miRNA-181a expression and induction of apoptosis.

14.
Braz J Cardiovasc Surg ; 37(3): 370-379, 2022 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-35605218

RESUMO

INTRODUCTION: The objective of this study is to investigate the protective mechanism of dexmedetomidine (Dex) in myocardial ischemia/reperfusion (MIR)-induced acute lung injury (ALI) of diabetic rats by inhibiting hypoxia-inducible factor-1α (HIF-1α). METHODS: Initially, healthy male Sprague Dawley rats were treated with streptozocin to induce diabetes. Then, three weeks after the induction, Dex or lentiviral vector (LV)-HIF-1α was injected into the rats 30 minutes prior to the MIR modeling. After four weeks, lung tissues were harvested for pathological changes observation and the wet/dry weight (W/D) ratio determination. Afterwards, oxidative stress indicators and pro-inflammatory factors were measured. In addition, HIF-1α expression was assessed by immunohistochemistry and western blot analysis. RESULTS: Dex could suppress inflammatory cell infiltration, improve lung tissue structure, reduce pathological score and the W/D ratio, and block oxidative stress and inflammatory response in MIR-induced ALI of diabetic rats. Besides, Dex could also inhibit HIF-1α expression. Moreover, Dex + LV-HIF-1α reversed the protective role of Dex on diabetic MIR-induced ALI. CONCLUSION: Our study has made it clear that Dex inhibited the upregulation of HIF-1α in diabetic MIR-induced ALI, and thus protect lung functions by quenching the accumulation of oxygen radical and reducing lung inflammatory response.


Assuntos
Lesão Pulmonar Aguda , Dexmedetomidina , Diabetes Mellitus Experimental , Traumatismo por Reperfusão Miocárdica , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/etiologia , Lesão Pulmonar Aguda/prevenção & controle , Animais , Dexmedetomidina/farmacologia , Dexmedetomidina/uso terapêutico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/patologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Pulmão/patologia , Masculino , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Ratos , Ratos Sprague-Dawley , Transdução de Sinais
15.
Proc Biol Sci ; 289(1970): 20212772, 2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35259989

RESUMO

Climate change has led to intensification and poleward migration of the Southeastern Pacific Anticyclone, forcing diverging regions of increasing, equatorward and decreasing, poleward coastal phytoplankton productivity along the Humboldt Upwelling Ecosystem, and a transition zone around 31° S. Using a 20-year dataset of barnacle larval recruitment and adult abundances, we show that striking increases in larval arrival have occurred since 1999 in the region of higher productivity, while slower but significantly negative trends dominate poleward of 30° S, where years of recruitment failure are now common. Rapid increases in benthic adults result from fast recruitment-stock feedbacks following increased recruitment. Slower population declines in the decreased productivity region may result from aging but still reproducing adults that provide temporary insurance against population collapses. Thus, in this region of the ocean where surface waters have been cooling down, climate change is transforming coastal pelagic and benthic ecosystems through altering primary productivity, which seems to propagate up the food web at rates modulated by stock-recruitment feedbacks and storage effects. Slower effects of downward productivity warn us that poleward stocks may be closer to collapse than current abundances may suggest.


Assuntos
Mudança Climática , Ecossistema , Cadeia Alimentar , Oceanos e Mares , Fitoplâncton
16.
Genes (Basel) ; 12(12)2021 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-34946979

RESUMO

Background: The microRNAs (miRNAs) are small noncoding single-stranded RNAs typically 19-25 nucleotides long and regulated by cellular and epigenetic factors. These miRNAs plays important part in several pathways necessary for cancer development, an altered miRNA expression can be oncogenic or tumor-suppressive. Recent experimental results on miRNA have illuminated a different perspective of the molecular pathogenesis of head and neck cancers. Regulation of miRNA can have a detrimental effect on the efficacy of chemotherapeutic drugs in both neoadjuvant and adjuvant settings. This miRNA-induced chemoresistance can influence the prognosis and survival rate. The focus of the study is on how regulations of various miRNA levels contribute to chemoresistance in head and neck cancer (HNC). Recent findings suggest that up or down-regulation of miRNAs may lead to resistance towards various chemotherapeutic drugs, which may influence the prognosis. Methods: Studies on miRNA-specific chemoresistance in HNC were collected through literary (bibliographic) databases, including SCOPUS, PubMed, Nature, Elsevier, etc., and were systematically reviewed following PRISMA-P guidelines (Preferred Reporting Items for Systematic Review and Meta-analysis Protocol). We evaluated various miRNAs, their up and downregulation, the effect of altered regulation on the patient's prognosis, resistant cell lines, etc. The data evaluated will be represented in the form of a review and meta-analysis. Discussion: This meta-analysis aims to explore the miRNA-induced chemoresistance in HNC and thus to aid further researches on this topic. PROSPERO registration: CRD42018104657.


Assuntos
Resistencia a Medicamentos Antineoplásicos , Neoplasias de Cabeça e Pescoço , MicroRNAs , Humanos , Biomarcadores Tumorais/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/genética , MicroRNAs/genética , Prognóstico , Taxa de Sobrevida , Revisões Sistemáticas como Assunto , Metanálise como Assunto
17.
Front Cell Neurosci ; 15: 743532, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34720881

RESUMO

CD146 is cell adhesion molecule and is implicated in a variety of physiological and pathological processes. However, the involvement of CD146 in peripheral nerve regeneration has not been studied yet. Here, we examine the spatial and temporal expression pattern of CD146 in injured mouse sciatic nerve via high-throughput data analysis, RT-PCR and immunostaining. By microarray data analysis and RT-PCR validation, we show that CD146 mRNA is significantly up-regulated in the nerve bridge and in the distal nerve stump following mouse sciatic nerve transection injury. By single cell sequencing data analysis and immunostaining, we demonstrate that CD146 is up-regulated in Schwann cells and cells associated with blood vessels following mouse peripheral nerve injury. Bioinformatic analysis revealed that CD146 not only has a key role in promoting of blood vessel regeneration but also regulates cell migration. The biological function of CD146 in Schwann cells was further investigated by knockdown of CD146 in rat primary Schwann cells. Functional assessments showed that knockdown of CD146 decreases viability and proliferation of Schwann cells but increases Schwann cell migration. Collectively, our findings imply that CD146 could be a key cell adhesion molecule that is up-regulated in injured peripheral nerves to regulate peripheral nerve regeneration.

18.
World J Nucl Med ; 20(3): 316-318, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34703403

RESUMO

We present a case of Grade II, well-differentiated rectal neuroendocrine tumor in a 39-year-old patient. Following different sequential treatment modalities, the disease progressed both on metabolic (18F-fluorodeoxyglucose positron emission tomography-computed tomography [18F-FDG PET/CT]) and somatostatin receptor (SSTR)-imaging (68Ga-DOTA-Tyr3-octreotate [68Ga-DOTATATE] PET/CT), and the patient received three cycles of peptide receptor radiotherapy (PRRT). Two years later, upon new progression due to the appearance of metabolically active, 68Ga-DOTATATE PET/CT-negative liver lesions, targeted treatment with everolimus was introduced. Further morphologic and metabolic progression occurred 4 months after everolimus initiation, however, this time liver lesions demonstrated increased SSTR-expression on68Ga-DOTATATE PET/CT. Thus, the patient became eligible for a second PRRT course.

19.
Proc Natl Acad Sci U S A ; 118(37)2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34504000

RESUMO

Ecologists are still puzzled by the diverse population dynamics of herbivorous small mammals that range from high-amplitude, multiannual cycles to stable dynamics. Theory predicts that this diversity results from combinations of climatic seasonality, weather stochasticity, and density-dependent food web interactions. The almost ubiquitous 3- to 5-y cycles in boreal and arctic climates may theoretically result from bottom-up (plant-herbivore) and top-down (predator-prey) interactions. Assessing, empirically, the roles of such interactions and how they are influenced by environmental stochasticity has been hampered by food web complexity. Here, we take advantage of a uniquely simple High Arctic food web, which allowed us to analyze the dynamics of a graminivorous vole population not subjected to top-down regulation. This population exhibited high-amplitude, noncyclic fluctuations-partly driven by weather stochasticity. However, the predominant driver of the dynamics was overcompensatory density dependence in winter that caused the population to frequently crash. Model simulations showed that the seasonal pattern of density dependence would yield regular 2-y cycles in the absence of stochasticity. While such short cycles have not yet been observed in mammals, they are theoretically plausible if graminivorous vole populations are deterministically bottom-up regulated. When incorporating weather stochasticity in the model simulations, cyclicity became disrupted and the amplitude was increased-akin to the observed dynamics. Our findings contrast with the 3- to 5-y population cycles that are typical of graminivorous small mammals in more complex food webs, suggesting that top-down regulation is normally an important component of such dynamics.


Assuntos
Arvicolinae/fisiologia , Mudança Climática , Cadeia Alimentar , Herbivoria , Plantas/metabolismo , Dinâmica Populacional , Estações do Ano , Animais , Regiões Árticas , Ecossistema
20.
Cell Biosci ; 11(1): 75, 2021 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-33865438

RESUMO

Hepatitis B virus (HBV) infection remains a major health issue worldwide and the leading cause of cirrhosis and hepatocellular carcinoma (HCC). It has been reported previously that HBV invasion can extensively alter transcriptome, the proteome of exosomes and host cell lipid rafts. The impact of HBV on host proteins through regulating their global post-translational modifications (PTMs), however, is not well studied. Viruses have been reported to exploit cellular processes by enhancing or inhibiting the ubiquitination of specific substrates. Nevertheless, host cell physiology in terms of global proteome and ubiquitylome has not been addressed yet. Here by using HBV-integrated HepG2.2.15 model cell line we first report that HBV significantly modify the host global ubiquitylome. As currently the most widely used HBV cell culture model, HepG2.2.15 can be cultivated for multiple generations for protein labeling, and can replicate HBV, express HBV proteins and secrete complete HBV Dane particles, which makes it a suitable cell line for ubiquitylome analysis to study HBV replication, hepatocyte immune response and HBV-related HCC progression. Our previous experimental results showed that the total ubiquitination level of HepG2.2.15 cell line was significantly higher than that of the corresponding parental HepG2 cell line. By performing a Ubiscan quantification analysis based on stable isotope labeling of amino acids in cell culture (SILAC) of HepG2.2.15 and HepG2 cell lines, we identified a total of 7188 proteins and the protein levels of nearly 19% of them were changed over 2-folds. We further identified 3798 ubiquitinated Lys sites in 1476 host proteins with altered ubiquitination in response to HBV. Our results also showed that the global proteome and ubiquitylome were negatively correlated, indicating that ubiquitination might be involved in the degradation of host proteins upon HBV integration. We first demonstrated the ubiquitination change of VAMP3, VAMP8, DNAJB6, RAB8A, LYN, VDAC2, OTULIN, SLC1A4, SLC1A5, HGS and TOLLIP. In addition, we described 5 novel host factors SLC1A4, SLC1A5, EIF4A1, TOLLIP and BRCC36 that efficiently reduced the amounts of secreted HBsAg and HBeAg. Overall, the HBV-mediated host proteome and ubiquitylome change we reported will provide a valuable resource for further investigation of HBV pathogenesis and host-virus interaction networks.

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