It is desirable to obtain high levels of viable Lacticaseibacillus paracasei, a widely used food probiotic whose antibacterial activity and potential application in milk remain largely ...uninvestigated. Here, we isolated and purified the L. paracasei strain XLK 401 from food-grade blueberry ferments and found that it exhibited strong antibacterial activity against both gram-positive and gram-negative foodborne pathogens, including Staphylococcus aureus, Salmonella paratyphi B, Escherichia coli O157, and Shigella flexneri. Then, we applied alternating tangential flow (ATF) technology to produce viable L. paracasei XLK 401 cells and its cell-free supernatant (CFS). Compared with the conventional fed-batch method, 22 h of ATF-based processing markedly increased the number of viable cells of L. paracasei XLK 401 to 12.14 ± 0.13 log cfu/mL. Additionally, the CFS exhibited good thermal stability and pH tolerance, inhibiting biofilm formation in the abovementioned foodborne pathogens. According to liquid chromatography-mass spectrometry analysis, organic acids were the main antibacterial components of XLK 401 CFS, accounting for its inhibition activity. Moreover, the CFS of L. paracasei XLK 401 effectively inhibited the growth of multidrug-resistant gram-positive Staph. aureus and gram-negative E. coli O157 pathogens in milk, and caused a reduction in the pathogenic cell counts by 6 to 7 log cfu/mL compared with untreated control, thus considerably maintaining the safety of milk samples. For the first time to our knowledge, ATF-based technology was employed to obtain viable L. paracasei on a large scale, and its CFS could serve as a broad-spectrum biopreservative for potential application against foodborne pathogens in milk products.
Transition metal dichalcogenide materials have been explored extensively as catalysts to negotiate the hydrogen evolution reaction, but they often run at a large excess thermodynamic cost. Although ...activating strategies, such as defects and composition engineering, have led to remarkable activity gains, there remains the requirement for better performance that aims for real device applications. We report here a phosphorus-doping-induced phase transition from cubic to orthorhombic phases in CoSe
. It has been found that the achieved orthorhombic CoSe
with appropriate phosphorus dopant (8 wt%) needs the lowest overpotential of 104 mV at 10 mA cm
in 1 M KOH, with onset potential as small as -31 mV. This catalyst demonstrates negligible activity decay after 20 h of operation. The striking catalysis performance can be attributed to the favorable electronic structure and local coordination environment created by this doping-induced structural phase transition strategy.
Nanoelectrodes allow precise and quantitative measurements of important biological processes at the single living‐cell level in real time. Cylindrical nanowire electrodes (NWEs) required for ...intracellular measurements create a great challenge for achieving excellent electrochemical and mechanical performances. Herein, we present a facile and robust solution to this problem based on a unique SiC‐core–shell design to produce cylindrical NWEs with superior mechanical toughness provided by the SiC nano‐core and an excellent electrochemical performance provided by the ultrathin carbon shell that can be used as such or platinized. The use of such NWEs for biological applications is illustrated by the first quantitative measurements of ROS/RNS in individual phagolysosomes of living macrophages. As the shell material can be varied to meet any specific detection purpose, this work opens up new opportunities to monitor quantitatively biological functions occurring inside cells and their organelles.
Nanoelectrodes for biology: A facile and robust strategy for the fabrication of high performance nanowire electrodes (NWEs) was developed. The NWEs allowed the measurement of reactive oxygen and nitrogen species (ROS/RNS) within individual phagolysosomes inside living macrophages.
Mitochondria are believed to be the major source of intracellular reactive oxygen species (ROS). However, in situ, real‐time and quantitative monitoring of ROS release from mitochondria that are ...present in their cytosolic environment remains a great challenge. In this work, a platinized SiC@C nanowire electrode is placed into a single cell for in situ detection of ROS signals from intracellular mitochondria, and antineoplastic agent (paclitaxel) induced ROS production is successfully recorded. Further investigations indicate that complex IV (cytochrome c oxidase, COX) is the principal site for ROS generation, and significantly more ROS are generated from mitochondria in cancer cells than that from normal cells. This work provides an effective approach to directly monitor intracellular mitochondria by nanowire electrodes, and consequently obtains important physiological evidence on antineoplastic agent‐induced ROS generation, which will be of great benefit for better understanding of chemotherapy at subcellular levels.
A platinized SiC@C nanowire electrode with excellent electrochemical and mechanical performance is fabricated and inserted into single cells to monitor reactive oxygen species (ROS) generation from intracellular mitochondria. This allows in situ quantification of paclitaxel‐induced ROS production in real time and identification of the site of which paclitaxel induces mitochondrial ROS generation inside single living cells.
The existence of a homeostatic mechanism regulating reactive oxygen/nitrogen species (ROS/RNS) amounts inside phagolysosomes has been invoked to account for the efficiency of this process but could ...not be unambiguously documented. Now, intracellular electrochemical analysis with platinized nanowire electrodes (Pt‐NWEs) allowed monitoring ROS/RNS effluxes with sub‐millisecond resolution from individual phagolysosomes impacting onto the electrode inserted inside a living macrophage. This shows for the first time that the consumption of ROS/RNS by their oxidation at the nanoelectrode surface stimulates the production of significant ROS/RNS amounts inside phagolysosomes. These results establish the existence of the long‐postulated ROS/RNS homeostasis and allows its kinetics and efficiency to be quantified. ROS/RNS concentrations may then be maintained at sufficiently high levels for sustaining proper pathogen digestion rates without endangering the macrophage internal structures.
Single nanowire electrode amperometry was used to establish that the consumption of ROS/RNS in a phagolysosome leads to a ROS/RNS production. This validates the long‐sought ROS/RNS homeostatic mechanism that was hypothesized to regulate the ROS/RNS intravesicular content during pathogens digestion.
Despite extensive literature on leadership and its impact employee innovative behavior, few studies have explored the relationship between inclusive leadership and employee innovative behavior. To ...address this gap, this study aimed to investigate how inclusive leadership influenced employee innovative behavior by examining perceived organizational support (POS) as a mediator. We used multi-wave and multi-source data collected at 15 companies in China to test our theoretical model. Results revealed that inclusive leadership had significantly positive effects on POS and employee innovative behavior. Furthermore, POS was positively related to employee innovative behavior and partially mediated the relationship between inclusive leadership and employee innovative behavior. We discussed implications and limitations of this study as well as avenues for future research.
Despite the fact that high‐valent nickel‐based oxides exhibit promising catalytic activity for the urea oxidation reaction (UOR), the fundamental questions concerning the origin of the high ...performance and the structure–activity correlations remain to be elucidated. Here, we unveil the underlying enhanced mechanism of UOR by employing a series of prepared cation‐vacancy controllable LiNiO2 (LNO) model catalysts. Impressively, the optimized layered LNO‐2 exhibits an extremely low overpotential at 10 mA cm−2 along with excellent stability after the 160 h test. Operando characterisations combined with the theoretical analysis reveal the activated lattice oxygen in layered LiNiO2 with moderate cation vacancies triggers charge disproportion of the Ni site to form Ni4+ species, facilitating deprotonation in a lattice oxygen involved catalytic process.
Beginning with cation‐vacancy controllable LiNiO2, the origin of the high performance and the structure–activity correlations was studied. The results indicate that lattice oxygen activated by cation vacancies triggered charge disproportionation to form high‐activity Ni4+, resulting in facilitating deprotonation in a lattice oxygen involved catalytic process.
Inorganic–organic hybrid molecular multiferroic and magnetoelectric materials, similar to multiferroic oxide compounds, have recently attracted increasing attention because they exhibit diverse ...architectures, a flexible framework, fascinating physics, and potential magnetoelectric functionalities in novel multifunctional devices such as energy transformation devices, sensors, and information storage systems. Herein, the classification of multiferroicity and magnetoelectricity is briefly outlined and then the recent advances in the multiferroicity and magnetoelectricity of inorganic–organic hybrid molecular materials, particularly magnetoelectricity and the relevant magnetoelectric mechanisms and their categories are summarized. In addition, a personal perspective and an outlook are provided.
Magnetoelectricity plays a huge role in the development of next‐generation devices. Since the discovery of multiferroic properties in inorganic–organic hybrid molecular materials, the related magnetoelectric behaviors have been gradually discovered and advanced at a vigorous pace. This brief development of multiferroicity/magnetoelectricity in inorganic–organic hybrid molecular materials shows their prospect for future development.
Chemical neurotransmission occurs at chemical synapses and endocrine glands, but up to now there was no means for direct monitoring of neurotransmitter exocytosis fluxes and their precise kinetics ...from inside an individual synapse. The fabrication of a novel finite conical nanoelectrode is reported perfectly suited in size and electrochemical properties for probing amperometrically inside what appears to be single synapses and monitoring individual vesicular exocytotic events in real time. This allowed obtaining direct and important physiological evidences which may yield important and new insights into the nature of synaptic communications.
Chemical neurotransmission occurs at chemical synapse, but up to now there was no means for direct monitoring of neurotransmitter exocytosis and its precise kinetics from inside individual infinitesimal synapse. A novel finite conical nanoelectrode is fabricated and used in a newly developed amperometric method (see picture) for probing inside what appears to be single synapses.
Glucose metabolism plays an important role in cell energy supply, and quantitative detection of the intracellular glucose level is particularly important for understanding many physiological ...processes. Glucose electrochemical sensors are widely used for blood and extracellular glucose detection. However, intracellular glucose detection cannot be achieved by these sensors owing to their large size and consequent low spatial resolution. Herein, we developed a single nanowire glucose sensor for electrochemical detection of intracellular glucose by depositing Pt nanoparticles (Pt NPs) on a SiC@C nanowire and further immobilizing glucose oxidase (GOD) thereon. Glucose was converted by GOD to an electroactive product H
2
O
2
which was further electro-catalyzed by Pt NPs. The glucose nanowire sensor is endowed with a high sensitivity, high spatial-temporal resolution and enzyme specificity due to its nanoscale size and enzymatic reaction. This allows the real-time monitoring of the intracellular glucose level, and the increase of the intracellular glucose level induced by a novel potential hypoglycemic agent, reinforcing its potential application in lowering the blood glucose level. This work provides a versatile method for the construction of enzyme-modified nanosensors to electrochemically detect intracellular non-electroactive molecules, which is of great benefit for physiological and pathological studies.
We report for the first time the development of a single nanowire electrochemical sensor for the detection of intracellular glucose levels.
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