62 research outputs found
Four Flavonoid Compounds from Phyllostachys edulis Leaf Extract Retard the Digestion of Starch and Its Working Mechanisms
Bamboo
leaf extract
as a food additive has been used for preventing
the oxidation of food. In the present study, we investigated the influence
of Phyllostachys edulis leaf extract
on starch digestion. Orientin, isoorientin, vitexin, and isovitexin
were determined as its α-amylase inhibitory constituents. An
inhibitory kinetics experiment demonstrated that they competitively
inhibit α-amylase with <i>K</i><sub>i</sub> values
of respectively 152.6, 11.5, 569.6, and 75.8 ÎĽg/mL. Molecular
docking showed the four flavones can interact with the active site
of α-amylase, and their inhibitory activity was greatly influenced
by the glucoside linking position and 3′-hydroxyl. Moreover,
the results of starch–iodine complex spectroscopy, X-ray diffraction,
and scanning electron microscopy indicated that P.
edulis flavonoids retard the digestion of starch not
only through interaction with digestive enzymes, but also through
interaction with starch. Thus, P. edulis leaf extract can be potentially used as a starch-based food additive
for adjusting postprandial hyperglycemia
Nanomechanical Characterization of Micellar Surfactant Films via Atomic Force Microscopy at a Graphite Surface
In this work, we
study the mechanical properties of sodium dodecyl
sulfate (SDS) and dodecylamine hydrochloride (DAH) micellar films
at a graphite surface via atomic force microscopy (AFM). Breakthrough
forces for these films were measured using silicon nitride cantilevers
and were found to be 1.1 ± 0.1 nN for a 10 mM DAH film and 3.0
± 0.3 nN for a 10 mM SDS film. For 10 mM SDS films, it was found
that the addition of 1.5 mM of NaCl, Na<sub>2</sub>SO<sub>4</sub>,
or MgCl<sub>2</sub> produced a 50–70% increase in the measured
breakthrough force. Similar results were found for 10 mM DAH films
when NaCl and MgCl<sub>2</sub> were added. A model was developed on
the basis of previous work on lipid films and CMC data gathered via
spectrofluorometry measurements to predict the change in normalized
breakthrough forces with added salt concentrations for SDS and DAH
films. Using this model, it was found that the activation volume required
to initiate the breakthrough was roughly 0.4 nm<sup>3</sup> for SDS
and 0.3 nm<sup>3</sup> for DAH, roughly the volume of a single molecule.
Normalized breakthrough force data for SDS films with added MgCl<sub>2</sub> showed an unexpected dip at low added salt concentrations.
The model was adapted to account for changing activation volumes,
and a curve of activation volume versus magnesium concentration was
obtained, showing a minimum volume of 0.21 nm<sup>3</sup>. The addition
of 0.2 mM SDS to a 10 mM DAH solution was found to double the measured
breakthrough force of the film. Images taken of the surface showed
a phase change from cylindrical hemimicelles to a planar film that
may have produced the observed differences. The pH of the bulk solution
was varied for both 10 mM SDS and DAH films and was found to have
little effect on the breakthrough force
Comparison of Regulation Mechanisms of Five Mulberry Ingredients on Insulin Secretion under Oxidative Stress
The
effects of mulberry ingredients including 1-deoxynojrimycin
(DNJ), resveratrol (RES), oxyresveratrol (OXY), cyanidin-3-glucoside
(C3G), and cyanidin-3-rutinoside (C3R) on insulin secretion under
oxidative stress were investigated. The results revealed that they
had distinct effects on insulin secretion in H<sub>2</sub>O<sub>2</sub>-induced MIN 6 cells, especially DNJ, C3G, and C3R, while RES and
OXY showed modest effects in low dose (12.5 ÎĽM). The mechanisms
were demonstrated in signal pathway that after treatment with DNJ,
C3G, and C3R, the expressions of glucokinase (GK) were up-regulated,
leading to intracellular ATP accumulation and insulin secretion. They
also bound to glucagon-like peptide-1 receptor (GLP-1R), improved
GLP-1R, duodenal homeobox factor-1 (PDX-1) expression, and stimulated
insulin secretion. Moreover, ROS production was inhibited, followed
by a decreasing apoptosis rate, while RES and OXY accelerated the
apoptosis at high dose (50 ÎĽM). This work expounded the potential
mechanisms of mulberry ingredients on insulin secretion, indicating
the potential application in the intervention against hyperglycemia
Multiple Comparisons of Glucokinase Activation Mechanisms of Five Mulberry Bioactive Ingredients in Hepatocyte
Glucokinase
(GK) activity, which is rapidly regulated by glucokinase
regulatory protein (GKRP) in the liver, is crucial for blood glucose
homeostasis. In this paper, the GK activation mechanisms of 1-deoxynojrimycin
(DNJ), resveratrol (RES), oxyresveratrol (OXY), cyanidin-3-glucoside
(C3G), and cyanidin-3-rutinoside (C3R) were compared. The results
revealed that DNJ, RES, C3G, and C3R could differently improve glucose
consumption and enhance intracellular GK activities. DNJ and RES significantly
promoted GK translocation at 12.5 ÎĽM, whereas other ingredients
showed moderate effects. DNJ, C3G, and C3R could rupture intramolecular
hydrogen bonds of GK to accelerate its allosteric activation at early
stage. RES and OXY could bind to a “hydrophobic pocket”
on GK to stabilize the active GK at the final stage. Otherwise, RES,
OXY, C3G, and C3R could interact with GKRP at the F1P binding site
to promote GK dissociation and translocation. Enzymatic assay showed
that RES (15–50 μM) and OXY (25–50 μM) could
significantly enhance GK activities, which was caused by their binding
properties with GK. Moreover, the most dramatic up-regulation effects
on GK expression were observed in C3G and C3R groups. This work expounded
the differences between GK activation mechanisms, and the new findings
would help to develop new GK activators
A new flavonoid from the aerial parts of <i>Andrographis paniculata</i>
<div><p>A new flavonoid, 7,8-dimethoxy-2′-hydroxy-5-<i>O</i>-β-d-glucopyranosyloxyflavone (<b>1</b>), along with 15 known flavonoids (<b>2–16</b>), was isolated from the aerial parts of <i>Andrographis paniculata</i> Nees. Their structures were elucidated on the basis of chemical and spectroscopic analyses. Most of them have uncommon <i>O</i>-substitution patterns involving 5-, 7-, 8-, 2′-, 3′-, 4′- and 5′-<i>O</i>-substituents. The antiproliferative effects of these flavonoids against human leukaemia HL-60 cells were investigated. Among them, <b>13</b> was the most active, displaying potent antiproliferative activity with IC<sub>50</sub> of 3.50 μM. The structure–activity relationships of these isolated compounds were discussed.</p></div
Bioprocess exploration for thermostable <i>α</i>-amylase production of a deep-sea thermophile <i>Geobacillus</i> sp. in high-temperature bioreactor
<p><i>Geobacillus</i> sp. 4j, a deep-sea high-salt thermophile, was found to produce thermostable α-amylase. In this work, culture medium and conditions were first optimized to enhance the production of thermostable α-amylase by statistical methodologies. The resulting extracellular production was increased by five times and reached 6.40 U/ml. Then, a high-temperature batch culture of the thermophile in a 15 l in-house-designed bioreactor was studied. The results showed that a relatively high dissolved oxygen (600 rpm and 15 l/min) and culture temperature of 60°C facilitated both cell growth and α-amylase production. Thus, an efficient fermentation process was established with initial medium of pH 6.0, culture temperature of 60°C, and dissolved oxygen above 20%. It gave an α-amylase production of 79 U/ml and productivity of 19804 U/l·hr, which were 10.8 and 208 times higher than those in shake flask, respectively. This work is useful for deep-sea high-salt thermophile culture, where efforts are lacking presently.</p
Phenotype of S-Ag specific T cells detected by intracellular cytokine staining
PBMCs from the active BD patients with a response to S-Ag were cultured with or without mixed S-Ag peptides plus anti-CD28 mAb and then were stained and examined by five color FCM. Lymphocytes were first gated using Forward Scatter (FSC) combined with Side Scatter (SSC), and then the CD3CD8 and CD3CD8 cells were gated for analyzing the expression of IFN-γ in CD4 T cells and the expression of IFN-γ in CD8 T cells. Lastly, the expressions of CD69 and CD45RO molecules on IFN-γCD4 and IFN-γCD8 T cells were analyzed, respectively. : The charts show the phenotypic feature of S-Ag specific T cells of one representative active BD patient. : The chart represents the expression of IFN-γ as the percentage of total CD4 or CD8 T cells in six different patients. Data were analyzed by Student’s -test.<p><b>Copyright information:</b></p><p>Taken from "S-antigen specific T helper type 1 response is present in Behcet’s disease"</p><p></p><p>Molecular Vision 2008;14():1456-1464.</p><p>Published online 07 Aug 2008</p><p>PMCID:PMC2496927.</p><p></p
Functional property of S-Ag specific T cells disclosed on the basis of cytokine secretion
PBMCs from all subjects were stimulated with or without mixed S-Ag peptides plus anti-CD28 for 72 h. The culture supernatants were collected and assessed for the production of IFN-γ (), TNF-α (), and IL-17 () by ELISA. The difference in cytokine levels between the negative control and S-Ag stimulation in four groups was analyzed using Student’s -test. The cytokine production by PBMCs upon S-Ag stimulation in each of the four groups was analyzed by ANOVA. Significant statistical difference was set at p<p><b>Copyright information:</b></p><p>Taken from "S-antigen specific T helper type 1 response is present in Behcet’s disease"</p><p></p><p>Molecular Vision 2008;14():1456-1464.</p><p>Published online 07 Aug 2008</p><p>PMCID:PMC2496927.</p><p></p
Capacity Fading Mechanism of the Commercial 18650 LiFePO<sub>4</sub>‑Based Lithium-Ion Batteries: An in Situ Time-Resolved High-Energy Synchrotron XRD Study
In
situ high-energy synchrotron XRD studies were carried out on commercial
18650 LiFePO<sub>4</sub> cells at different cycles to track and investigate
the dynamic, chemical, and structural changes in the course of long-term
cycling to elucidate the capacity fading mechanism. The results indicate
that the crystalline structural deterioration of the LiFePO<sub>4</sub> cathode and the graphite anode is unlikely to happen before capacity
fades below 80% of the initial capacity. Rather, the loss of the active
lithium source is the primary cause for the capacity fade, which leads
to the appearance of inactive FePO<sub>4</sub> that is proportional
to the absence of the lithium source. Our in situ HESXRD studies further
show that the lithium-ion insertion and deinsertion behavior of LiFePO<sub>4</sub> continuously changed with cycling. For a fresh cell, the
LiFePO<sub>4</sub> experienced a dual-phase solid-solution behavior,
whereas with increasing cycle numbers, the dynamic change, which is
characteristic of the continuous decay of solid solution behavior,
is obvious. The unpredicted dynamic change may result from the morphology
evolution of LiFePO<sub>4</sub> particles and the loss of the lithium
source, which may be the cause of the decreased rate capability of
LiFePO<sub>4</sub> cells after long-term cycling
DataSheet_1_Acute stress induces an inflammation dominated by innate immunity represented by neutrophils in mice.docx
It is well known that psychological stress could affect the immune system and then regulate the disease process. Previous studies mostly focused on the effects of chronic stress on diseases and immune cells. How acute stress affects the immune system remains poorly understood. In this study, after 6 hours of restraint stress or no stress, RNA was extracted from mouse peripheral blood followed by sequencing. Through bioinformatics analysis, we found that when compared with the control group, differentially expressed genes in the stress group mainly displayed up-regulated expression. Gene set enrichment analysis results showed that the enriched gene terms were mainly related to inflammatory response, defense response, wounding response, wound healing, complement activation and pro-inflammatory cytokine production. In terms of cell activation, differentiation and chemotaxis, the enriched gene terms were related to a variety of immune cells, among which neutrophils seemed more active in stress response. The results of gene set variation analysis showed that under acute stress, the inflammatory reaction dominated by innate immunity was forming. Additionally, the concentration of serum IL-1β and IL-6 increased significantly after acute stress, indicating that the body was in an inflammatory state. Importantly, we found that acute stress led to a significant increase in the number of neutrophils in peripheral blood, while the number of T cells and B cells decreased significantly through flow cytometric analysis. Through protein-protein interaction network analysis, we screened 10 hub genes, which mainly related to inflammation and neutrophils. We also found acute stress led to an up-regulation of Ccr1, Ccr2, Xcr1 and Cxcr2 genes, which were involved in cell migration and chemotaxis. Our data suggested that immune cells were ready to infiltrate into tissues in emergency through blood vessels under acute stress. This hypothesis was supported in LPS-induced acute inflammatory models. After 48 hours of LPS treatment, flow cytometric analysis showed that the lungs of mice with acute stress were characterized by increased neutrophil infiltration, decreased T cell and B cell infiltration. Immunohistochemical analysis also showed that acute stress led to more severe lung inflammation. If mice received repeat acute stress and LPS stimulation, the survival rate was significantly lower than that of mice only stimulated by LPS. Altogether, acute stress led to rapid mobilization of the immune system, and the body presented an inflammatory state dominated by innate immune response represented by neutrophils.</p
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