RESUMO
Batten disease, the most prevalent form of neurodegeneration in children, is caused by mutations in the CLN3 gene, which encodes a lysosomal transmembrane protein. CLN3 loss leads to significant accumulation of glycerophosphodiesters (GPDs), the end products of glycerophospholipid catabolism in the lysosome. Despite GPD storage being robustly observed upon CLN3 loss, the role of GPDs in neuropathology remains unclear. Here, we demonstrate that GPDs act as potent inhibitors of glycerophospholipid catabolism in the lysosome using human cell lines and mouse models. Mechanistically, GPDs bind and competitively inhibit the lysosomal phospholipases PLA2G15 and PLBD2, which we establish to possess phospholipase B activity. GPDs effectively inhibit the rate-limiting lysophospholipase activity of these phospholipases. Consistently, lysosomes of CLN3-deficient cells and tissues accumulate toxic lysophospholipids. Our work establishes that the storage material in Batten disease directly disrupts lysosomal lipid homeostasis, suggesting GPD clearance as a potential therapeutic approach to this fatal disease.
Assuntos
Glicoproteínas de Membrana , Lipofuscinoses Ceroides Neuronais , Camundongos , Animais , Criança , Humanos , Glicoproteínas de Membrana/metabolismo , Chaperonas Moleculares/metabolismo , Lipofuscinoses Ceroides Neuronais/genética , Lipofuscinoses Ceroides Neuronais/metabolismo , Lipofuscinoses Ceroides Neuronais/patologia , Lisossomos/metabolismo , Fosfolipases/metabolismo , Glicerofosfolipídeos/metabolismo , Fosfolipídeos/metabolismoRESUMO
Group A rotaviruses (RVAs) are a major cause of severe enteritis in humans and animals. RVAs have been identified in several animal species and their genetic diversity, the segmented nature of their RNA genome and the ability to spill over from one species to another can generate new RVA strains. In this study, we investigated the genome constellations of an unusual, rare, bovine RVA strain, G15P[21], identified from a farm with neonatal diarrhoea of calves in 2006. In parallel, the genome constellations of other RVA strains with different G/P types identified from the same farm in the same time span (2006-2008) were analysed. The genome constellation of strain K53 was G15-P[21]-I2-R2-C2-M2-A13-N2-T9-E2-H3 and was similar, overall, to that of the other bovine RVA strains (G6/10-P[11]-I2-R2-C2-M2-A13-N2-T6-E2-H3) with the exception of the NSP3 segment (T9 vs T6). This study describes RVA genomes with different genotype combinations isolated at a farm and also contributes to the understanding of the diversity and evaluation of rotavirus in a global context.
Assuntos
Infecções por Rotavirus , Rotavirus , Bovinos , Animais , Humanos , Recém-Nascido , Rotavirus/genética , Infecções por Rotavirus/veterinária , Fazendas , Genoma Viral , Filogenia , GenótipoRESUMO
Group A rotaviruses (RVAs) infect a wide variety of mammalian and avian species. Animals act as a potential reservoir to RVA human infections by direct virion transmission or by contributing genes to reassortants. Here, we report the molecular characterization of a rare human RVA strain Ni17-46 with a genotype G15P[14], isolated in Japan in 2017 during rotavirus surveillance in a paediatric outpatient clinic. The genome constellation of this strain was G15-P[14]-I2-R2-C2-M2-A13-N2-T9-E2-H3. This is the first report of an RVA with G15 genotype in humans, and sequencing and phylogenetic analysis results suggest that human infection with this strain has zoonotic origin from the bovine species. Given the fact that this strain was isolated from a patient with gastroenteritis and dehydration symptoms, we must take into account the virulence of this strain in humans.
Assuntos
Gastroenterite/virologia , Genoma Viral , Infecções por Rotavirus/virologia , Rotavirus , Zoonoses Virais/virologia , Adolescente , Animais , Bovinos/virologia , Feminino , Genótipo , Humanos , Japão , Rotavirus/genética , Rotavirus/isolamento & purificaçãoRESUMO
G-protein coupled estrogen receptor 1 (GPER1) is a novel type of estrogen receptor. Several studies have shown that it has an anti-inflammatory action,which plays an important role in remyelination and cognitive ability adjustment. However, whether it is involved in the development of temporal lobe epilepsy (TLE) is still unknown. The present study established a TLE model by intraperitoneal injection of lithium chloride (3 mmol/kg) and pilocarpine (50 mg/kg) in rats to study the effect of GPER1 in the synaptic plasticity during the development of temporal lobe epilepsy. A microinjection cannula was implanted into the lateral ventricle region of rats via a stereotaxic instrument. G-1 is the specific GPER1 agonist and G15 is the specific GPER1 antagonist. The G1 or G15 and Dimethyl sulfoxide were injected into the rat brains in the intervention groups and control group, respectively. After G1 intervention, the learning and memory abilities and hippocampal neuron damage in epileptic rats were significantly improved, while G15 weakened the neuroprotective effect of GPER1. Meanwhile, G1 controlled the abnormal formation of hippocampal mossy fiber sprouting caused by seizures, and participated in the regulation of synaptic plasticity by reducing the expression of Synapsin I and increasing the expression of gephyrin. Inhibitory synapse gephyrin may play a significant role in synaptic plasticity.
Assuntos
Epilepsia do Lobo Temporal/metabolismo , Plasticidade Neuronal/fisiologia , Receptores Acoplados a Proteínas G/metabolismo , Animais , Epilepsia do Lobo Temporal/induzido quimicamente , Epilepsia do Lobo Temporal/etiologia , Epilepsia do Lobo Temporal/patologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Aprendizagem/efeitos dos fármacos , Cloreto de Lítio , Masculino , Proteínas de Membrana/metabolismo , Memória/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Pilocarpina , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Sinapsinas/metabolismoRESUMO
BACKGROUND: Hepatic fibrosis is the final pathway of chronic liver disease characterized by excessive accumulation of extracellular matrix (ECM), which eventually develop into cirrhosis and liver cancer. Emerging studies demonstrated that Saikosaponin-d (SSd) exhibits a protective role in liver fibrosis. However, the mechanism underlying anti-liver fibrosis of SSd in vivo and in vitro remains unclear. METHODS AND RESULTS: Transforming growth factor (TGF)-ß and carbon tetrachloride (CCl4) were used for creating liver fibrosis model in vitro and in vivo, respectively. The role of SSd in regulating liver fibrosis was assessed through Sirius red and Masson staining, and IHC assay. We found that SSd attenuated remarkably CCl4-induced liver fibrosis as evidenced by decreased collagen level, and decreased expression of fibrotic markers Col 1 and α-SMA. Meanwhile, SSd repressed autophagy activation as suggested by decreased BECN1 expression and increased p62 expression. Compared with HSCs from CCl4-treated group, the primary HSCs from SSd-treated mice exhibited a marked inactivation of autophagy. Mechanistically, SSd treatment enhanced the expression of GPER1 in primary HSCs and in TGF-ß-treated LX-2 cells. GPER1 agonist G1 repressed autophagy activation, whereas GPER1 antagonist G15 activated autophagy and G15 also damaged the function of SSd on suppressing autophagy, leading to subsequent increased levels of fibrotic marker level in LX-2 cells. CONCLUSIONS: Our findings highlight that SSd alleviates hepatic fibrosis by regulating GPER1/autophagy pathway.
Assuntos
Cirrose Hepática/tratamento farmacológico , Ácido Oleanólico/análogos & derivados , Receptores de Estrogênio/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Saponinas/farmacologia , Animais , Autofagia/fisiologia , Tetracloreto de Carbono/farmacologia , Células Cultivadas , China , Fibrose , Células Estreladas do Fígado/efeitos dos fármacos , Células Estreladas do Fígado/metabolismo , Humanos , Fígado/metabolismo , Cirrose Hepática/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ácido Oleanólico/metabolismo , Ácido Oleanólico/farmacologia , Saponinas/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismoRESUMO
Female-specific subpopulation of myelinated Ah-type baroreceptor neurons (BRNs) in nodose ganglia is the neuroanatomical base of sexual-dimorphic autonomic control of blood pressure regulation, and KCa1.1 is a key player in modulating the neuroexcitation in nodose ganglia. In this study we investigated the exact mechanisms underlying KCa1.1-mediated neuroexcitation of myelinated Ah-type BRNs in the presence or absence of estrogen. BRNs were isolated from adult ovary intact (OVI) or ovariectomized (OVX) female rats, and identified electrophysiologically and fluorescently. Action potential (AP) and potassium currents were recorded using whole-cell recording. Consistently, myelinated Ah-type BRNs displayed a characteristic discharge pattern and significantly reduced excitability after OVX with narrowed AP duration and faster repolarization largely due to an upregulated iberiotoxin (IbTX)-sensitive component; the changes in AP waveform and repetitive discharge of Ah-types from OVX female rats were reversed by G1 (a selective agonist for estrogen membrane receptor GPR30, 100 nM) and/or IbTX (100 nM). In addition, the effect of G1 on repetitive discharge could be completely blocked by G15 (a selective antagonist for estrogen membrane receptor GPR30, 3 µM). These data suggest that estrogen deficiency by removing ovaries upregulates KCa1.1 channel protein in Ah-type BRNs, and subsequently increases AP repolarization and blunts neuroexcitation through estrogen membrane receptor signaling. Intriguingly, this upregulated KCa1.1 predicted electrophysiologically was confirmed by increased mean fluorescent intensity that was abolished by estrogen treatment. These electrophysiological findings combined with immunostaining and pharmacological manipulations reveal the crucial role of KCa1.1 in modulation of neuroexcitation especially in female-specific subpopulation of myelinated Ah-type BRNs and extend our current understanding of sexual dimorphism of neurocontrol of BP regulation.
Assuntos
Estrogênios/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Neurônios/metabolismo , Gânglio Nodoso/metabolismo , Pressorreceptores/metabolismo , Animais , Estrogênios/deficiência , Feminino , Neurônios/efeitos dos fármacos , Ovariectomia , Ovário/citologia , Ovário/cirurgia , Pressorreceptores/efeitos dos fármacos , Quinolinas/farmacologia , Ratos Sprague-DawleyRESUMO
Transcription and translation retrieve and operationalize gene encoded information in cells. These processes are not instantaneous and incur significant delays. In this paper we study Goodwin models of both inducible and repressible operons with state-dependent delays. The paper provides justification and derivation of the model, detailed analysis of the appropriate setting of the corresponding dynamical system, and extensive numerical analysis of its dynamics. Comparison with constant delay models shows significant differences in dynamics that include existence of stable periodic orbits in inducible systems and multistability in repressible systems. A combination of parameter space exploration, numerics, analysis of steady state linearization and bifurcation theory indicates the likely presence of Shilnikov-type homoclinic bifurcations in the repressible operon model.
Assuntos
ÓperonRESUMO
Cisplatin is the major chemotherapeutic drug in gastric cancer, particularly in treating advanced gastric cancer. Tumour cells often develop resistance to chemotherapeutic drugs, which seriously affects the efficacy of chemotherapy. GPR30 is a novel oestrogen receptor that is involved in the invasion, metastasis and drug resistance of many tumours. Targeting GPR30 has been shown to increase the drug sensitivity of breast cancer cells. However, few studies have investigated the role of GPR30 in gastric cancer. Epithelial-mesenchymal transition (EMT) has been shown to be associated with the development of chemotherapeutic drug resistance. In this study, we demonstrated that GPR30 is involved in cisplatin resistance by promoting EMT in gastric cancer. GPR30 knockdown resulted in increased sensitivity of different gastric cancer (GC) cells to cisplatin and alterations in the epithelial/mesenchymal markers. Furthermore, G15 significantly enhanced the cisplatin sensitivity of GC cells while G1 inhibited this phenomenon. In addition, EMT occurred when AGS and BGC-823 were treated with cisplatin. Down-regulation of GPR30 with G15 inhibited this transformation, while G1 promoted it. Taken together, these results revealed the role of GPR30 in the formation of cisplatin resistance, suggesting that targeting GPR30 signalling may be a potential strategy for improving the efficacy of chemotherapy in gastric cancer.
Assuntos
Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Receptores de Estrogênio/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Linhagem Celular Tumoral , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , HumanosRESUMO
We present an analysis of two Haken-Kelso-Bunz (HKB) oscillators coupled by a neurologically motivated function. We study the effect of time delay and weighted self-feedback and mutual feedback on the synchronization behavior of the model. We focus on identifying parameter regimes supporting experimentally observed decrease in oscillation amplitude and loss of anti-phase stability that has inspired the development of the HKB model. We show that a combination of cross-talk and nonlinearity in the coupling, along with physiologically relevant time delay, is able to quantitatively account for both drop in oscillation amplitude and loss of anti-phase stability in a frequency dependent manner. Furthermore, we demonstrate that the transition between discrete and rhythmic movements could be captured by this model. To this end, we carry out theoretical and numerical analysis of the emergence of in-phase and anti-phase oscillations.
RESUMO
Electrical coupling between neurons is broadly present across brain areas and is typically assumed to synchronize network activity. However, intrinsic properties of the coupled cells can complicate this simple picture. Many cell types with electrical coupling show a diversity of post-spike subthreshold fluctuations, often linked to subthreshold resonance, which are transmitted through electrical synapses in addition to action potentials. Using the theory of weakly coupled oscillators, we explore the effect of both subthreshold and spike-mediated coupling on synchrony in small networks of electrically coupled resonate-and-fire neurons, a hybrid neuron model with damped subthreshold oscillations and a range of post-spike voltage dynamics. We calculate the phase response curve using an extension of the adjoint method that accounts for the discontinuous post-spike reset rule. We find that both spikes and subthreshold fluctuations can jointly promote synchronization. The subthreshold contribution is strongest when the voltage exhibits a significant post-spike elevation in voltage, or plateau potential. Additionally, we show that the geometry of trajectories approaching the spiking threshold causes a "reset-induced shear" effect that can oppose synchrony in the presence of network asymmetry, despite having no effect on the phase-locking of symmetrically coupled pairs.
RESUMO
The present study assessed the participation of membrane G-protein coupled estrogen receptor 1 (GPER-1) and gonadotropin releasing hormone 1 (GnRH-1) receptor in the display of lordosis induced by intracerebroventricular (icv) administration of G1, a GPER-1 agonist, and by unesterified 17ß-estradiol (free E2). In addition, we assessed the participation of both estrogen and progestin receptors in the lordosis behavior induced by G1 in ovariectomized (OVX), E2-benzoate (EB)-primed rats. In Experiment 1, icv injection of G1 induced lordosis behavior at 120 and 240min. In Experiment 2, icv injection of the GPER-1 antagonist G15 significantly reduced lordosis behavior induced by either G1 or free E2. In addition, Antide, a GnRH-1 receptor antagonist, significantly depressed G1 facilitation of lordosis behavior in OVX, EB-primed rats. Similarly, icv injection of Antide blocked the stimulatory effect of E2 on lordosis behavior. In Experiment 3, systemic injection of either tamoxifen or RU486 significantly reduced lordosis behavior induced by icv administration of G1 in OVX, EB-primed rats. The results suggest that GnRH release activates both estrogen and progestin receptors and that this activation is important in the chain of events leading to the display of lordosis behavior in response to activation of GPER-1 in estrogen-primed rats.
Assuntos
Estradiol/farmacologia , Postura/fisiologia , Receptores de Estrogênio/fisiologia , Receptores Acoplados a Proteínas G/agonistas , Receptores LHRH/fisiologia , Receptores de Progesterona/fisiologia , Comportamento Sexual Animal/efeitos dos fármacos , Animais , Feminino , Antagonistas de Hormônios/farmacologia , Mifepristona/farmacologia , Oligopeptídeos/farmacologia , Ratos , Ratos Sprague-Dawley , Comportamento Sexual Animal/fisiologia , Tamoxifeno/farmacologiaRESUMO
We obtain formulae for the expected number and height distribution of critical points of smooth isotropic Gaussian random fields parameterized on Euclidean space or spheres of arbitrary dimension. The results hold in general in the sense that there are no restrictions on the covariance function of the field except for smoothness and isotropy. The results are based on a characterization of the distribution of the Hessian of the Gaussian field by means of the family of Gaussian orthogonally invariant (GOI) matrices, of which the Gaussian orthogonal ensemble (GOE) is a special case. The obtained formulae depend on the covariance function only through a single parameter (Euclidean space) or two parameters (spheres), and include the special boundary case of random Laplacian eigenfunctions.
RESUMO
Estradiol rapidly modulates hippocampal synaptic plasticity and synaptic transmission; however, the contribution of the various estrogen receptors to rapid changes in synaptic function is unclear. This study examined the effect of estrogen receptor selective agonists on hippocampal synaptic transmission in slices obtained from 3-5-month-old wild type (WT), estrogen receptor alpha (ERαKO), and beta (ERßKO) knockout female ovariectomized mice. Hippocampal slices were prepared 10-16 days following ovariectomy and extracellular excitatory postsynaptic field potentials were recorded from CA3-CA1 synaptic contacts before and following application of 17ß-estradiol-3-benzoate (EB, 100 pM), the G-protein estrogen receptor 1 (GPER1) agonist G1 (100 nM), the ERα selective agonist propyl pyrazole triol (PPT, 100 nM), or the ERß selective agonist diarylpropionitrile (DPN, 1 µM). Across all groups, EB and G1 increased the synaptic response to a similar extent. Furthermore, prior G1 application occluded the EB-mediated enhancement of the synaptic response and the GPER1 antagonist, G15 (100 nM), inhibited the enhancement of the synaptic response induced by EB application. We confirmed that the ERα and ERß selective agonists (PPT and DPN) had effects on synaptic responses specific to animals that expressed the relevant receptor; however, PPT and DPN produced only a small increase in synaptic transmission relative to EB or the GPER1 agonist. We demonstrate that the increase in synaptic transmission is blocked by inhibition of extracellular signal-regulated kinase (ERK) activity. Furthermore, EB was able to increase ERK activity regardless of genotype. These results suggest that ERK activation and enhancement of synaptic transmission by EB involves multiple estrogen receptor subtypes.
Assuntos
Estradiol/farmacologia , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Estrogênios/farmacologia , Hipocampo/efeitos dos fármacos , Receptores de Estrogênio/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Antagonistas do Receptor de Estrogênio/farmacologia , Receptor alfa de Estrogênio/agonistas , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/agonistas , Receptor beta de Estrogênio/genética , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Hipocampo/fisiologia , Camundongos Knockout , Nitrilas/farmacologia , Ovariectomia , Fenóis/farmacologia , Propionatos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Receptores de Estrogênio/antagonistas & inibidores , Receptores de Estrogênio/genética , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/genética , Técnicas de Cultura de TecidosRESUMO
We have hypothesized that estradiol enhances basal forebrain cholinergic function and cognitive performance, at least in part, via activation of the novel estrogen receptor GPR30. Here we evaluated the effects of estradiol, G-1 (a selective GPR30 agonist), and tamoxifen (TAM; an ERα/ERß antagonist that also acts as a GPR30 agonist), on acetylcholine (ACh) release in the hippocampus, as well as the ability to block the effects of 17ß-estradiol (E) or TAM with the GPR30 antagonist G-15. Note that G-1 was included to evaluate the effects of selectively activating GPR30, whereas TAM was included to differentiate effects of E associated with activation of GPR30 vs. ERα or ERß. The study was designed to test effects on potassium-stimulated release, as well as on ACh release stimulated by feeding. Effects of feeding were included because the tasks we used previously to demonstrate beneficial effects of E on cognitive performance were motivated by food reward, and we hypothesized that E may enhance performance by increasing ACh release in association with that reward. Ovariectomized rats were treated for 1week, and ACh release was evaluated using in vivo microdialysis. In addition, rats were fed at the same time daily for several days and were fasted overnight prior to microdialysis. For each rat, ACh release was evaluated under basal conditions, in response to feeding, and in response to elevated potassium. Both feeding and elevated potassium increased ACh release in the hippocampus. In response to feeding, E, G-1, and TAM all significantly increased the percent change in release. The effects of E and TAM were blocked by G-15, and the effects of combining E+TAM did not differ significantly from the effects of E or TAM alone. In response to elevated potassium, E, and TAM significantly increased the percent change in ACh release. G-1 produced a slightly lesser effect. The effect of TAM was reduced by G-15, but the effect of E was not. These findings suggest that activation of GPR30 is both necessary and sufficient to account for the effects of E on ACh release associated with feeding. In contrast, activation of GPR30 appears to be sufficient, but may not be necessary for increased release associated with elevated potassium. The changes associated with feeding are consistent with the effects of E, G-1 and G-15 on acquisition of a spatial learning task previously described. These data confirm and extend previous reports, and support a hypothesis wherein E treatment can improve learning on specific tasks by activating GPR30 and enhancing ACh release in association with food reward.
Assuntos
Acetilcolina/metabolismo , Estradiol/farmacologia , Hipocampo/metabolismo , Receptores Acoplados a Proteínas G/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Condicionamento Operante/efeitos dos fármacos , Estradiol/metabolismo , Antagonistas de Estrogênios/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Feminino , Hipocampo/efeitos dos fármacos , Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Tamoxifeno/farmacologiaRESUMO
This paper analyses the effects of containment measures and monetary and fiscal responses on US financial markets during the Covid-19 pandemic. More specifically, it applies fractional integration methods to analyse their impact on the daily S&P500, the US Treasury Bond Index (USTB), the S&P Green Bond Index (GREEN) and the Dow Jones (DJ) Islamic World Market Index (ISLAM) over the period 1/01/2020-10/03/2021. The results suggest that all four indices are highly persistent and exhibit orders of integration close to 1. A small degree of mean reversion is observed only for the S&P500 under the assumption of white noise errors and USTB with autocorrelated errors; therefore, market efficiency appears to hold in most cases. The mortality rate, surprisingly, seems to have affected stock and bond prices positively with autocorrelated errors. As for the policy responses, both the containment and fiscal measures had a rather limited impact, whilst there were significant announcement effects which lifted markets, especially in the case of monetary announcements. There is also evidence of a significant, positive response to changes in the effective Federal funds rate, which suggests that the financial industry, mainly benefiting from interest rises, plays a dominant role.
RESUMO
Four GH16 family ß-agarases (GH16A, GH16B, GH16C, and GH16D), originated from an agarolytic bacterium Cellvibrio sp. KY-GH-1, were expressed in an Escherichia coli system and their activities were compared. Only GH16B (597 amino acids, 63.8 kDa), with N-terminal 22-amino acid signal sequence, was secreted into the culture supernatant and demonstrated a robust endolytic agarose hydrolyzing activity for producing neoagarotetraose (NA4) and neoagarohexaose (NA6) as end products. The optimal temperature and pH for the enzyme activity were 50 °C and 7.0, respectively. The enzyme was stable up to 50 °C and over a pH range of 5.0-8.0. The kinetic parameters, including Km, Vmax, kcat, and kcat/Km, of GH16B ß-agarases for agarose were 14.40 mg/mL, 542.0 U/mg, 576.3 s-1, and 4.80 × 106 s-1 M-1, respectively. The addition of 1 mM MnCl2 and 15 mM tris(2-carboxyethyl)phosphine enhanced the enzymatic activity. When agarose or neoagaro-oligosaccharides were used as substrates, the end products of enzymatic catalysis were NA4 and NA6, whereas agaropentaose was produced along with NA4 and NA6 when agaro-oligosaccharides were used as substrates. Treatment of 9%[w/v] melted agarose with the enzyme (1.6 µg/mL) under continuous magnetic stirring at 50 °C for 14 h resulted in efficient agarose liquefaction into NA4 and NA6. Purification of NA4 and NA6 from the enzymatic hydrolysate (9%[w/v] agarose, 20 mL) via Sephadex G-15 column chromatography yielded ~ 650 mg NA4/~ 900 mg NA6 (i.e., ~ 85.3% of the theoretical maximum yield). These findings suggest that the recombinant thermostable GH16B ß-agarase is useful for agarose liquefaction to produce NA4 and NA6.
RESUMO
The empirical research that is presented herein deals with the process of transferring negative impulses in capital markets during the subprime crisis (contagion, comovements, crisis transmission and shocks). A significant and positive contribution of the research conducted is the demonstration of how the wavelet analysis can be used in examining the various responses of the financial markets. The first stage of the research involved an analysis of the response of seven European markets (CAC40, DAX, FTSE100, IBEX, ATHEX, BUX and WIG20 indexes) to the proceedings in the US market, exemplified by the Dow Jones Industrial Average Index. The second stage involved examining the relationships of strong European markets (CAC40, DAX, FTSE100), and then the impact that the strongest German market DAX had on four other and weaker European markets - two from Western Europe (IBEX, ATHEX) and two from Central-Eastern Europe (BUX and WIG20). This article presents a methodological approach to transfer impulses on capital markets.
RESUMO
We consider the imaginary Gaussian multiplicative chaos, i.e. the complex Wick exponential µ ß : = : e i ß Γ ( x ) : for a log-correlated Gaussian field Γ in d ≥ 1 dimensions. We prove a basic density result, showing that for any nonzero continuous test function f, the complex-valued random variable µ ß ( f ) has a smooth density w.r.t. the Lebesgue measure on C . As a corollary, we deduce that the negative moments of imaginary chaos on the unit circle do not correspond to the analytic continuation of the Fyodorov-Bouchaud formula, even when well-defined. Somewhat surprisingly, basic density results are not easy to prove for imaginary chaos and one of the main contributions of the article is introducing Malliavin calculus to the study of (complex) multiplicative chaos. To apply Malliavin calculus to imaginary chaos, we develop a new decomposition theorem for non-degenerate log-correlated fields via a small detour to operator theory, and obtain small ball probabilities for Sobolev norms of imaginary chaos.
RESUMO
Pepper root rot is a serious soil-borne disease that hinders pepper production, and efforts are being made to identify biological agents that can prevent and control pepper root rot. Our group recently discovered and produced a biological agent, named G15, which reduces the diversity and richness of fungi and bacteria when applied to pepper fields. In the soil of the G15-treatment condition, the pathogenic fungus Fusarium was inhibited, while the richness of beneficial bacteria Rhodanobacter was increased. Also, the ammonia nitrogen level was decreased in the G15-treatment soil, and the pH, total carbon, and total potassium levels were increased. Compared to the control condition, pepper yield was increased in the treatment group (by 16,680 kg acre-1). We found that G15 could alter the microbial community structure of the pepper rhizosphere. These changes alter the physical and chemical properties of the soil and, ultimately, improve resistance to pepper root rot and increase pepper yield.
RESUMO
Research has shown that cartilage containing chondroitin sulfate and protein presents versatile bioactivities. Chondroitin sulfate in cartilage is beneficial to activate the immune system while the protein/peptide has not been fully understood. The current study investigated the antioxidant and anti-inflammatory properties of ethanol-soluble hydrolysates of sturgeon cartilage (ESCH) prepared through hot-pressure, enzymatic hydrolysis and ethanol extraction. UV spectrum, IR and agarose gel electrophoresis results suggested the successful exclusion of chondroitin sulfate from peptides. Nitric oxide (NO) floods in cells activated by inflammation. It was inhibited when administrated with ESCH. To further explain the observed anti-inflammatory activity, ESCH was separated with Sephadex G-15 into 3 components, among which F3 showed a higher NO inhibition rate and significantly reduced the production of the proinflammatory cytokine IL-6. In addition, the yield of IL-10 increased. Western blotting suggested that F3 downregulated the NO content and IL-6 level by suppressing Mitogen-activated protein kinases (MAPK) channels. Moreover, both ESCH and F3 showed DPPH and ABTS free radical scavenging abilities which was possibly related to the anti-inflammatory property. These results indicated that ESCH behaved anti-inflammatory and antioxidant activities. Cartilage may be a good source to produce anti-inflammatory peptides.