Many cellular functions are driven by changes in the intracellular Ca2+ concentration ([Ca2+]i) that are highly organized in time and space. Ca2+ oscillations are particularly important in this respect and are based on positive and negative [Ca2+]i feedback on inositol 1,4,5-trisphosphate receptors (InsP3Rs). Connexin hemichannels are Ca2+-permeable plasma membrane channels that are also controlled by [Ca2+]i. We aimed to investigate how hemichannels may contribute to Ca2+ oscillations. Madin-Darby canine kidney cells expressing connexin-32 (Cx32) and Cx43 were exposed to bradykinin (BK) or ATP to induce Ca2+ oscillations. BK-induced oscillations were rapidly (minutes) and reversibly inhibited by the connexin-mimetic peptides 32Gap27/43Gap26, whereas ATP-induced oscillations were unaffected. Furthermore, these peptides inhibited the BK-triggered release of calcein, a hemichannel-permeable dye. BK-induced oscillations, but not those induced by ATP, were dependent on extracellular Ca2+. Alleviating the negative feedback of [Ca2+]i on InsP3Rs using cytochrome c inhibited BK- and ATP-induced oscillations. Cx32 and Cx43 hemichannels are activated by <500 nm [Ca2+]i but inhibited by higher concentrations and CT9 peptide (last 9 amino acids of the Cx43 C terminus) removes this high [Ca2+]i inhibition. Unlike interfering with the bell-shaped dependence of InsP3Rs to [Ca2+]i, CT9 peptide prevented BK-induced oscillations but not those triggered by ATP. Collectively, these data indicate that connexin hemichannels contribute to BK-induced oscillations by allowing Ca2+ entry during the rising phase of the Ca2+ spikes and by providing an OFF mechanism during the falling phase of the spikes. Hemichannels were not sufficient to ignite oscillations by themselves; however, their contribution was crucial as hemichannel inhibition stopped the oscillations. Many cellular functions are driven by changes in the intracellular Ca2+ concentration ([Ca2+]i) that are highly organized in time and space. Ca2+ oscillations are particularly important in this respect and are based on positive and negative [Ca2+]i feedback on inositol 1,4,5-trisphosphate receptors (InsP3Rs). Connexin hemichannels are Ca2+-permeable plasma membrane channels that are also controlled by [Ca2+]i. We aimed to investigate how hemichannels may contribute to Ca2+ oscillations. Madin-Darby canine kidney cells expressing connexin-32 (Cx32) and Cx43 were exposed to bradykinin (BK) or ATP to induce Ca2+ oscillations. BK-induced oscillations were rapidly (minutes) and reversibly inhibited by the connexin-mimetic peptides 32Gap27/43Gap26, whereas ATP-induced oscillations were unaffected. Furthermore, these peptides inhibited the BK-triggered release of calcein, a hemichannel-permeable dye. BK-induced oscillations, but not those induced by ATP, were dependent on extracellular Ca2+. Alleviating the negative feedback of [Ca2+]i on InsP3Rs using cytochrome c inhibited BK- and ATP-induced oscillations. Cx32 and Cx43 hemichannels are activated by <500 nm [Ca2+]i but inhibited by higher concentrations and CT9 peptide (last 9 amino acids of the Cx43 C terminus) removes this high [Ca2+]i inhibition. Unlike interfering with the bell-shaped dependence of InsP3Rs to [Ca2+]i, CT9 peptide prevented BK-induced oscillations but not those triggered by ATP. Collectively, these data indicate that connexin hemichannels contribute to BK-induced oscillations by allowing Ca2+ entry during the rising phase of the Ca2+ spikes and by providing an OFF mechanism during the falling phase of the spikes. Hemichannels were not sufficient to ignite oscillations by themselves; however, their contribution was crucial as hemichannel inhibition stopped the oscillations.
The efficacy of colistin, the last option against multidrug-resistant (MDR) Gram-negative bacteria, is severely threatened by the prevalence of plasmid- or chromosome-mediated colistin resistance genes. Herein, naringenin has dramatically restored colistin sensitivity against colistin-resistant Klebsiella pneumoniae infection without affecting bacterial viability, inducing resistance and causing obvious cell toxicity. Mechanism analysis reveals that naringenin potentiates colistin activity by multiple strategies including inhibition of mobilized colistin resistance gene activity, repression of two-component system regulation, and acceleration of reactive oxygen species-mediated oxidative damage. A lung-targeted delivery system of naringenin microspheres has been designed to facilitate naringenin bioavailability, accompanied by an effective potentiation of colistin for Klebsiella pneumoniae infection. Consequently, a new recognition of naringenin microspheres has been elucidated to restore colistin efficacy against colistin-resistant Gram-negative pathogens, which may be an effective strategy of developing potential candidates for MDR Gram-negative bacteria infection.
With the standardization and promotion of laparoscopic technology, totally laparoscopic radical gastrectomy (TLRG) has been applied widely. The main difficult points of TLRG focus on digestive tract reconstruction. The common methods of digestive tract reconstruction in TLRG include circular stapler, linear stapler and manual suture. Compared with the circular stapler method and manual suture method, the linear stapler has the advantages of simple operation, better field of vision and larger caliber of anastomotic stoma. This article introduces and evaluates the common anastomotic methods of digestive tract reconstruction with linear stapler in TLRG.
Key words:
Stomach neoplasm; Laparoscopy; Gastrectomy; Anastomosis
Milk thistle is a traditional medicinal herb. Silybin is a medicinal component found in the seed coat of milk thistle, which has liver-protective and anti-cancer properties. Conventional studies have focused on the extraction of silybin with organic reagents, which was inapplicable to the food industry. This study aims to develop a fermented milk containing silybin and protein from the milk thistle seeds. A three step procedure was developed, comprising homogenization of milk thistle seeds, NaHCO3 heat treatment, and microbial fermentation. The silybin was characterized by high performance liquid chromatography, and the protein was quantified and electrophorized. It was found that the homogenization step was essential for the preparation of protein, and the NaHCO3 heat treatment was the crucial step in obtaining silybin. The optimal NaHCO3 treatment settings were 1% NaHCO3, 60°C, and 3 h, and the optimal strains for microbial fermentation were L131 (Rummeliibacillus stabekisii) and RS72 (Lactobacillus plantarum). The silybin yield in the fermented milk reached 11.24-12.14 mg/g seeds, accounting for 72.6-78.4% of the total silybin in the milk thistle seeds, and the protein yield reached 121.8-129.6 mg/g seeds. The fermented milk had a slightly sweet yoghurt-like flavor and could be used as a dietary supplement for silybin and protein.
Transdermal patches of rotigotine, a dopamine agonist of the non-ergoline class, are used to treat the signs and symptoms of Parkinson’s disease. In this study, we have probed the effect of ginseng oral liquid on the efficacy of the rotigotin patch plus amantadine in treating Parkinson’s disease. Measurements of mental behavior, daily activities, and motor function were used to calculate the total effective rate of the treatment that was elevated in the presence of ginseng oral liquid. While ginseng oral liquid lowered the Parkinson’s Disease Questionnaire scores and levels of serum amyloid A and interleukin-12, it augmented apolipoprotein A1. No difference was seen in the incidence of adverse events between the two groups. To sum up, rotigotin patches in association with amantadine and ginseng oral liquid are effective in treating Parkinson’s disease, which can effectively promote the quality of life of patients, decrease clinical symptoms, and reduce inflammatory reactions.
Abstract α-Synuclein inclusions are a pathological hallmark of several neurodegenerative diseases. Although it has been demonstrated a relationship between fibril polymorphism and different pathologies, the molecular origins of polymorphism are not understood. Employing biophysical approaches, we revealed that the conformational state of the monomeric αSyn is responsible for fibril polymorphism: αSyn adopts specific conformations at high NaCl that produce rod fibrils, and different conformations at low NaCl that generate twisted fibrils. Using NMR, we found that the high NaCl conformations establish a polar interaction between the initial part of the NAC region and a wide section of the C-terminus domain. These high NaCl conformations can be commonly promoted by changes in the chemical environment, like NaCl, the presence of Ca 2+ or cellular components, like endotoxins, that alter the interaction NAC/C-terminus domain. Our results provide mechanistic insights that explain how the behavior of the C-terminus domain imparts polymorphism during the fibril formation. Significance Statement The accumulation of the protein α-Synuclein into amyloid aggregates in the brain is a key characteristic of neurodegenerative disorders like Parkinson’s disease and multiple system atrophy. Intensive research has demonstrated that structurally different amyloid fibrils are related to the development of different diseases; however, the molecular mechanisms that originate such fibril diversity from the same protein remain unknown. In this work, we discovered that the conformational state of the monomeric αSyn, regulated by an intramolecular polar interaction NAC region/C-terminus domain, is crucial for the generation of different fibrils. Our results represent the monomeric molecular events behind the diversity of fibrils and open the conformational state of αSyn as a target to understand how the fibrils get formed in the brain.
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