Genome-wide transcription landscape of citric acid producing Aspergillus niger in response to glucose gradient.

Aspergillus niger is the main industrial workhorse for global citric acid production. This fungus has complex sensing and signaling pathways to respond to environmental nutrient fluctuations. As the preferred primary carbon source, glucose also acts as a critical signal to trigger intracellular bioprocesses. Currently, however, there is still a knowledge gap in systems-level understanding of metabolic and cellular responses to this vital carbon source. In this study, we determined genome-wide transcriptional changes of citric acid-producing Aspergillus niger in response to external glucose gradient. It demonstrated that external glucose fluctuation led to transcriptional reprogramming of many genes encoding proteins involved in fundamental cellular process, including ribosomal biogenesis, carbon transport and catabolism, glucose sensing and signaling. The major glucose catabolism repressor creA maintained a stable expression independent of external glucose, while creB and creD showed significant downregulation and upregulation by the glucose increase. Notably, several high-affinity glucose transporters encoding genes, including mstA, were greatly upregulated when glucose was depleted, while the expression of low-affinity glucose transporter mstC was glucose-independent, which showed clear concordance with their protein levels detected by in situ fluorescence labeling assay. In addition, we also observed that the citric acid exporter cexA was observed to be transcriptionally regulated by glucose availability, which was correlated with extracellular citric acid secretion. These discoveries not only deepen our understanding of the transcriptional regulation of glucose but also shed new light on the adaptive evolutionary mechanism of citric acid production of A. niger.

Few-layer MoS2 nanosheets vertically supported on Ti3C2-MXene sheets promoting lithium storage performance.

2H phase MoS2 with a two-dimensional nanostructure, high chemical stability and large theoretical capacity has been considered as a potential anode material for lithium-ion batteries. However, some practical problems hinder the direct use of 2H-MoS2 for lithium storage, such as its volume expansion effect that leads to capacity loss and its semiconductor properties that cannot provide sufficient conductivity. Herein, the surface of an MXene with abundant surface groups was modified with CTAB to promote its ability to adsorb MoO42- anions, and then 2H-MoS2 with a few layers was directly grown on the surface of MXene sheets vertically. Thanks to the conductive MXene sheets and the vertically-supported high-capacity MoS2 on them, the as-obtained composite MXene@MoS2 offers enhanced performance in specific capacity, long cycling stability and high rate capability. A reversible specific capacity of 1198 mA h g-1 was retained after 100 cycles at 200 mA g-1 and a specific capacity of 717 mA h g-1 was exhibited at 8000 mA g-1.

Unique Tubular BiOBr/g-C3 N4 Heterojunction with Efficient Separation of Charge Carriers for Photocatalytic Nitrogen Fixation.

The industrial ammonia synthesis process consumes a lot of energy and causes serious environmental pollution. As a sustainable approach for ammonia synthesis, photocatalytic nitrogen reduction employing water as the reducing agent has a lot of potential. A simple surfactant-assisted solvothermal method is used to synthesize g-C3 N4 nanotubes with flower-like spherical BiOBr grown inside and outside (BiOBr/g-C3 N4 , BC). The hollow tubular structure realizes the full use of visible light by the multi-scattering effect of light. Large surface areas and more active sites for N2 adsorption and activation are present in the distinctive spatially dispersed hierarchical structures. Particularly, the quick separation and transfer of electrons and holes are facilitated by the sandwich tubular heterojunctions and tight contact interface of BiOBr and g-C3 N4 . The maximal NH3 generation rate of the BiOBr/g-C3 N4 composite catalysts can reach 255.04 µmol⋅ g-1 ⋅ h-1 , and it is 13.9 and 5.8 times that of pure BiOBr and g-C3 N4 . This work provides a novel method for designing and constructing unique heterojunctions for efficient photocatalytic nitrogen fixation.

The opening of mitochondrial permeability transition pore (mPTP) and the inhibition of electron transfer chain (ETC) induce mitophagy in wheat roots under waterlogging stress.

Mitochondria are crucial for the regulation of intracellular energy metabolism, biosynthesis, and cell survival. And studies have demonstrated the role of mitochondria in oxidative stress-induced autophagy in plants. Previous studies found that waterlogging stress can induce the opening of mitochondrial permeability transition pore (mPTP) and the release of cytochrome c in endosperm cells, which proved that mPTP plays an important role in the programmed cell death of endosperm cells under waterlogging stress. This study investigated the effects of the opening of mPTP and the inhibition of ETC on mitophagy in wheat roots under waterlogging stress. The results showed that autophagy related genes in the mitochondria of wheat root cells could respond to waterlogging stress; waterlogging stress led to the degradation of the characteristic proteins cytochrome c and COXII in the mitochondria of root cells. With the prolongation of waterlogging time, the protein degradation degree and the occurrence of mitophagy gradually increased. Under waterlogging stress, exogenous mPTP opening inhibitor CsA inhibited mitophagy in root cells and alleviated mitophagy induced by flooding stress, while exogenous mPTP opening inducer CCCP induced mitophagy in root cells; exogenous mPTP opening inducer CCCP induced mitophagy in root cells. The electron transfer chain inhibitor antimycin A induces mitophagy in wheat root cells and exacerbates mitochondrial degradation. In conclusion, waterlogging stress led to the degradation of mitochondrial characteristic proteins and the occurrence of mitophagy in wheat root cells, and the opening of mPTP and the inhibition of ETC induced the occurrence of mitophagy.

Constructing NCuS Interface Chemical Bonds over SnS2 for Efficient Solar-Driven Photoelectrochemical Water Splitting.

The restricted charge transfer and slow oxygen evolution reaction (OER) dynamics tremendously hamper the realistic implementation of SnS2 photoanodes for photoelectrochemical (PEC) water splitting. Here, a novel strategy is developed to construct interfacial NCuS bonds between NC skeletons and SnS2 (CuNC@SnS2 ) for efficient PEC water splitting. Compared with SnS2 , the PEC activity of CuNC@SnS2 photoelectrode is tremendously heightened, obtaining a current density of 3.40 mA cm2 at 1.23 VRHE with a negatively shifted onset potential of 0.04 VRHE , which is 6.54 times higher than that of SnS2 . The detailed experimental characterizations and theoretical calculation demonstrate that the interfacial NCuS bonds enhance the OER kinetic, reduce the surface overpotential, facilitate the separation of photon-generated carriers, and provide a fast transmission channel for electrons. This work presents a new approach for modulating charge transfer by interfacial bond design in heterojunction photoelectrodes toward promoting PEC performance and solar energy application.

Oxygen vacancy engineering of novel ultrathin Bi12O17Br2 nanosheets for boosting photocatalytic N2 reduction.

The conversion of N2 to NH3 is one of the most promising processes in maintaining natural life and chemical production. Photocatalytic nitrogen reduction reaction (NRR) has the advantage of clean and sustainable, which is considered to be an ideal synthesis technology. In this work, we report the successful synthesis of Bi12O17Br2 ultrathin nanosheets through simple alkali treatment and solvothermal method. The Bi12O17Br2 ultrathin nanosheets can improve the separation of carriers and the transfer of photogenerated electrons to N2 molecules, thus improving the photocatalytic efficiency. Of note, the higher Bi/Br atomic ratio in Bi12O17Br2 is beneficial to broaden the light absorption edge, and the high concentration of O atoms is easy to produce oxygen vacancies on the surface during the synthesis process of Bi12O17Br2. The abundant oxygen vacancies and high specific surface area enable N2 molecules and water to have powerful chemical adsorption and activation. In addition, the photocatalytic reduction of N2 to NH3 in pure water shows excellent and stable performance, and the average generation rate of NH3 reaches up to 620.5 µmol·L-1·h-1. This study discovers that rich oxygen vacancies and ultrathin morphology may have a significant part in the process of the photocatalytic nitrogen reduction reaction.

A novel sensitive ACNTs-MoO2 SERS substrate boosted by synergistic enhancement effect.

Integrating chemical enhancement (CM) and electromagnetic enhancement (EM) into one substrate is of great significance, but as far as we know, little research has been done on this project. In this paper, the novel bead chain like acidified carbon nanotubes-MoO2 (ACNTs-M) were designed by a simple two-step hydrothermal synthesis method. Benefitting from a good adsorption capacity, chemical enhancement and surface electromagnetic field enhancement effect, ACNTs-M exhibits a stunning SERS performance. The maximum enhancement factor (EF) of 5.13 × 107 is obtained with R6G molecules on ACNTs-M. The limit of detection (LOD) of R6G is 10-10 M. In addition, ACNTs-M also exhibits SERS sensitivity of other organic dyes (CV, RhB and MB). The results of Raman signal enhancement mechanism research verified that the synergy of CM and EM is the reason for the high SERS sensitivity of ACNTs-M. We believe that our work may bring cutting edge of development of stable and highly sensitive nonmetal SERS substrates.

Short-term waterlogging-induced autophagy in root cells of wheat can inhibit programmed cell death.

Autophagy is a pathway for the degradation of cytoplasmic components in eukaryotes. In wheat, the mechanism by which autophagy regulates programmed cell death (PCD) is unknown. Here, we demonstrated that short-term waterlogging-induced autophagy inhibited PCD in root cells of wheat. The waterlogging-tolerant wheat cultivar Huamai 8 and the waterlogging-sensitive wheat cultivar Huamai 9 were used as experimental materials, and their roots were waterlogged for 0-48 h. Waterlogging stress increased the number of autophagic structures, the expression levels of autophagy-related genes (TaATG), and the occurrence of PCD in root cells. PCD manifested as morphological changes in the cell nucleus, significant enhancement of DNA laddering bands, and increases in caspase-like protease activity and the expression levels of metacaspase genes. The autophagy promoter rapamycin (RAPA) reduced PCD levels, whereas the autophagy inhibitor 3-methyladenine (3-MA) enhanced them. The expression levels of TaATG genes and the number of autophagic structures were lower in cortex cells than in stele cells, but the levels of PCD were higher in cortex cells. The number of autophagic structures was greater in Huamai 8 than in Huamai 9, but the levels of PCD were lower. In summary, our results showed that short-term waterlogging induced autophagy which could inhibit PCD. Mechanisms of response to waterlogging stress differed between cortex and stele cells and between two wheat cultivars of contrasting waterlogging tolerance.

Characteristics of clinical studies of summer acupoint herbal patching: a bibliometric analysis.

BACKGROUND: Summer acupoint herbal patching (SAHP) has been widely used in China for thousands of years. This bibliometric analysis aims to provide a comprehensive review of the characteristics of clinical studies on SAHP for any condition. METHODS: We included clinical studies such as randomized clinical trials (RCTs), controlled clinical studies (CCTs), case series (CSs), case reports (CRs), and cross-sectional studies on SAHP for any condition. Six databases were searched from date of inception to March 2015. Bibliometric information and study details such as study type, characteristics of participants, details of the intervention and comparison, and outcome were extracted and analyzed. RESULTS: A total of 937 clinical studies were identified and which were published between 1977 and 2015. This included 404 RCTs, 52 CCTs, 458 CSs, 19 CRs and 4 cross-sectional studies and involved 232,138 participants aged 2 to 90 years from two countries. Almost all studies were from China (936, 99.89%). The five conditions most commonly treated by SAHP were asthma (401, 42.80%), chronic bronchitis (146, 15.58%), allergic rhinitis (117, 12.49%), chronic obstructive pulmonary disease (73, 7.79%), and recurrent respiratory tract infection (42, 4.48%). Among 502 controlled studies, the majority compared SAHP alone with different controls (16 categories, 275 comparisons). The most commonly used controls were western medicine, placebo, traditional Chinese medicine, no treatment and non-pharmaceutical traditional Chinese therapies. Composite outcome measures were the most frequently reported outcome (512, 69.19%). CONCLUSION: A substantial amount of research on SAHP has been published in China and which predominantly focuses on respiratory conditions. The findings from this study can be used to inform further research by highlighting areas of greatest impact for SAHP.