One-step growth of Cu-doped carbon dots in amino-modified carbon nanotube-modified electrodes for sensitive electrochemical detection of BPA

Copper-doped carbon dots and aminated carbon nanotubes (Cu-CDs/NH2-CNTs) nanocomposites were synthesized by a one-step growth method, and the composites were characterized for their performance. An electrochemical sensor for sensitive detection of bisphenol A (BPA) was developed for using Cu-CDs/NH2-CNTs nanocomposites modified with glassy carbon electrodes (GCE). The sensor exhibited an excellent electrochemical response to BPA in 0.2 M PBS (pH 7.0) under optimally selected conditions. The linear range of the sensor for BPA detection was 0.5-160 μM, and the detection limit (S/N = 3) was 0.13 μM. Moreover, the sensor has good interference immunity, stability and reproducibility. In addition, the feasibility of the practical application of the sensor was demonstrated by the detection of BPA in bottled drinking water and Liu Yang River water.

Biological characterization of emerging fungal pathogen Colletotrichum associated with mango (Mangifera indica L.) post-harvest anthracnose from Vietnam

BACKGROUND

Post-harvest anthracnose (PHA) of mango is a devastating disease, which results in huge loss to mango producers and importers. Various species of PHA, diverse pathogenicity, and different resistance towards fungicides make it essential to evaluate the pathogen taxonomic status and biological characterization.

METHODS AND RESULTS

Two strains DM-1 and DM-2 isolated from the fruit of DaQing mango from Vietnam were identified as Colletotrichum fructicola and C. asianum respectively, based on the morphological features, along with the phylogenetic tree of ITS and ApMat combined sequences. The growth status of different Colletotrichum strains under different conditions was analyzed to reveal the biological characteristics. The optimum growth temperature of DM-1 and DM-2 was 28 °C and mycelia grew rapidly in the dark. Both strains could grow in media with pH 4-11, while the optimum pH value was 6. Maltose and soluble starch were the most suitable carbon source for DM-1 and DM-2 respectively, and the peptone was the most suitable nitrogen source for both strains. The lethal temperatures were recorded as 55 °C 5 min for DM-1, and 50 °C 10 min for DM-2.

CONCLUSIONS

To the best of our knowledge, it is the first study reporting the identification of the pathogens: C. fructicola and C. asianum responsible for postharvest fruit anthracnose of mango in Vietnam.

Metabarcode insights into the airborne fungal diversity in the indoor and outdoor environments in archives from Yunnan, Southwestern China

Monitoring dynamics of airborne fungal species and controlling of harmful ones are of vital importance to conservation of cultural relics. However, the evaluation of air quality and the community structure characteristics of microorganisms, especially fungi, in the atmosphere of archives is in a stage of continuous exploration though more than 4,000 archives were constructed in China. Seventy-two air samples were collected in this study under different spatial and weather conditions from the archives of Kunming Medical University, located in the Kunming metropolitan area, Yunnan province, southwestern China. A total of 22 airborne fungal classes, 160 genera and 699 ASVs were identified, the species diversity is on the rise with the strengthening of air circulation with the outside space, and thus the intensive energy metabolism and activity were found in the spaces with window and sunny weather, except for the higher lipid synthesis of indoor samples than that of outdoor ones. Furthermore, there were significant differences in fungal community composition and abundance between sunny and rainy weathers. A considerable number of species have been identified as indicator in various environmental and weather conditions of the archives, and temperature and humidity were thought to have significant correlations with the abundance of these species. Meanwhile, Cladosporium and Alternaria were the dominant genera here, which may pose a threat to the health of archive professionals. Therefore, monitoring and controlling the growth of these fungal species is crucial for both conservation of paper records and health of archive professionals.

Kangfuxin liquid reduces the ultraviolet B-induced photodamage of HaCaT cells by regulating autophagy

Kangfuxin liquid (KFX), an extract of the American cockroach, has been clinically proven to be effective in various skin damage disorders, but there are no reports on its use in photodamage. We explored the effect of KFX on ultraviolet B (UVB)-induced photodamage and whether its mechanism was related to autophagy. We found that KFX treatment reduced UVB-induced reactive oxygen species production and improved the vitality of cells inhibited by UVB irradiation. The expression of LC3 (A/B), which was inhibited after UVB irradiation, could be rescued by KFX treatment. Furthermore, KFX may upregulate the level of cellular autophagy by regulating the AMPK-mTOR signaling pathway. When the autophagy inhibitor wortmannin was used to inhibit autophagy, the protective effect of KFX on cells was diminished or even disappeared. Our study suggests that KFX may resist UVB-mediated oxidative stress damage of HaCaT through the induction of autophagy.

Secondary Metabolites from the Nematode-Trapping Fungus Dactylellina haptotyla YMF1.03409

As a representative nematode-trapping fungus, Dactylellina haptotyla can capture and kill nematodes by producing traps, known as adhesive knobs. In this paper, the strain of D. haptotyla YMF1.03409 was studied by means of medium screening, fermentation, and purification and identification of crude extracts. Eighteen compounds were obtained from D. haptotyla YMF1.03409, including two new metabolites, nosporins C (1) and D (2). The known metabolites were identified to be 3-chloro-4-methoxybenzaldehyde (3), 3-chloro-4-methoxybenzoic acid (4), 2-chloro-1-methoxy-4-(methoxymethyl)benzene (5), 3-hydroxy-3-methyloxindole (6), nicotinic acid (7), succinic acid (8), 3,4-dihydroxybutanoic acid (9), 5'-O-methyladenosine (10), uridine (11), 2'-deoxyuridine (12), thymidine (13), 3-(phenylmethyl)-2,5-morpholinedione (14), methyl-β-D-glucopyranoside (15), 1,2-benzenedicarboxylic acid bis(2-methyl heptyl) ester (16), β-sitosterol (17), and 3β,6α-diol-stigmastane (18). The bioactive assay showed that these compounds had no obvious nematicidal activity against the nematodes Meloidogyne incognita and Panagrellus redivivus.

AfLaeA, a Global Regulator of Mycelial Growth, Chlamydospore Production, Pathogenicity, Secondary Metabolism, and Energy Metabolism in the Nematode-Trapping Fungus Arthrobotrys flagrans

Arthrobotrys flagrans (Duddingtonia flagrans) is a typical nematode-trapping fungus which has been used for nematode biocontrol. The global regulator LaeA is widely distributed in filamentous fungi and plays a crucial role in secondary metabolism and development in addition to pathogenicity in fungal pathogens. In this study, the chromosome-level genome of A. flagrans CBS 565.50 was sequenced and homologous sequences of LaeA were identified in A. flagrans. A. flagrans LaeA (AfLaeA) knockout resulted in slower hyphal growth and a smoother hyphal surface. Importantly, deletion of AfLaeA resulted in the absence of chlamydospores and attenuated glycogen and lipid accumulation in hyphae. Similarly, disruption of the AfLaeA gene led to fewer traps and electron-dense bodies, lower protease activity, and a delay in capturing nematodes. The AfLaeA gene had a large effect on the secondary metabolism of A. flagrans, and both the deletion and overexpression of AfLaeA could yield new compounds, whereas some compounds were lost due to the absence of the AfLaeA. Protein-protein interactions between AfLaeA and another eight proteins were detected. Furthermore, transcriptome data analysis showed that 17.77% and 35.51% of the genes were influenced by the AfLaeA gene on days 3 and 7, respectively. AfLaeA gene deletion resulted in the higher expression level of the artA gene cluster, and multiple differentially expressed genes involved in glycogen and lipid synthesis and metabolism showed opposite expression patterns in wild-type and ΔAfLaeA strains. In summary, our results provide novel insights into the functions of AfLaeA in mycelial growth, chlamydospore production, pathogenicity, secondary metabolism, and energy metabolism in A. flagrans. IMPORTANCE The regulation of biological functions, such as the secondary metabolism, development, and pathogenicity of LaeA, has been reported in multiple fungi. But to date, no study on LaeA in nematode-trapping fungi has been reported. Moreover, it has not been investigated whether or not LaeA is involved in energy metabolism and chlamydospore formation has not been investigated. Especially in the formation mechanism of chlamydospores, several transcription factors and signaling pathways are involved in the production of chlamydospores, but the mechanism of chlamydospore formation from an epigenetic perspective has not been revealed. Concurrently, an understanding of protein-protein interactions will provide a broader perspective on the regulatory mechanism of AfLaeA in A. flagrans. This finding is critical for understanding the regulatory role of AfLaeA in the biocontrol fungus A. flagrans and establishes a foundation for developing high-efficiency nematode biocontrol agents.

Facile UV-Induced Surface Covalent Modification to Fabricate Durable Superhydrophobic Fabric for Efficient Oil-Water Separation

In this work, a durable superhydrophobic fabric was fabricated by using a facile UV-induced surface covalent modification strategy. 2-isocyanatoethylmethacrylate (IEM) containing isocyanate groups can react with the pre-treated hydroxylated fabric, producing IEM molecules covalently grafted onto the fabric's surface, and the double bonds of IEM and dodecafluoroheptyl methacrylate (DFMA) underwent a photo-initiated coupling reaction under UV light radiation, resulting in the DFMA molecules further grafting onto the fabric's surface. The Fourier transform infrared, X-ray photoelectron spectroscopy and scanning electron microscopy results revealed that both IEM and DFMA were covalently grafted onto the fabric's surface. The formed rough structure and grafted low-surface-energy substance contributed to the excellent superhydrophobicity (water contact angle of ~162°) of the resultant modified fabric. Notably, such a superhydrophobic fabric can be used for efficient oil-water separation, for example a high separation efficiency of over 98%. More importantly, the modified fabric exhibited excellent durable superhydrophobicity in harsh conditions such as immersion in organic solvents for 72 h, an acidic or alkali solution (pH = 1-12) for 48 h, undergoing laundry washing for 3 h, exposure to extreme temperatures (from -196° to 120°), as well as damage such as 100 cycles of tape-peeling and a 100-cycle abrasion test; the water contact angle only slightly decreased from ~162° to 155°. This was attributed to the IEM and DFMA molecules grated onto the fabric through stable covalent interactions, which could be accomplished using the facile strategy, where the alcoholysis of isocyanate and the grafting of DFMA via click coupling chemistry were integrated into one-step. Therefore, this work provides a facile one-step surface modification strategy for preparing durable superhydrophobic fabric, which is promising for efficient oil-water separation.

Transplantation of Nurr1-overexpressing neural stem cells and microglia for treating parkinsonian rats

BACKGROUND

Neural stem cells (NSCs) transplantation is considered a promising treatment for Parkinson's disease. But most NSCs are differentiated into glial cells rather than neurons, and only a few of them survive after transplantation due to the inflammatory environment.

METHODS

In this study, neural stem cells (NSCs) and microglial cells both forced with the Nurr1 gene were transplanted into the striatum of the rat model of PD. The results were evaluated through reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunofluorescence analysis.

RESULTS

The behavioral abnormalities of PD rats were improved by combined transplantation of NSCs and microglia, both forced with Nurr1. The number of tyrosine hydroxylase+ cells in the striatum of PD rats increased, and the number of Iba1+ cells decreased compared with the other groups. Moreover, the dopamine neurons differentiated from grafted NSCs could still be detected in the striatum of PD rats after 5 months.

CONCLUSIONS

The results suggested that transplantation of Nurr1-overexpressing NSCs and microglia could improve the inhospitable host brain environments, which will be  a new potential strategy for the cell replacement therapy in PD.

Effect of nicotine from tobacco root exudates on chemotaxis, growth, biocontrol efficiency, and colonization by Pseudomonas aeruginosa NXHG29

Accumulated evidence suggests that root exudates have a major role in mediating plant-microbe interactions in the rhizosphere. Here, we characterized tobacco root exudates (TREs) by GC-MS and nicotine, scopoletin, and octadecane were identified as three main components of TREs. Qualitative and quantitative chemotaxis assays revealed that Pseudomonas aeruginosa NXHG29 with antagonistic activity displayed positive chemotactic responses towards TREs and their three main components (nicotine, scopoletin, octadecane) and its enhanced chemotaxis were induced by these substances in a concentration-dependent manner. Furthermore, following GC-MS and chemotaxis analysis, nicotine was selected as the target for evaluation of the effect on NXHG29 regarding antagonism, growth, root colonization and biocontrol efficiency. Results of in vitro studies showed that nicotine as a sole carbon source could enhance growth of NXHG29 and significantly increased the antagonism of NXHG29. We also demonstrated that nicotine exerted enhancing effects on the colonization ability of NXHG29 on tobacco roots by combining CLSM observations with investigation of population level dynamics by selective dilution plating method. Results from greenhouse experiments suggested nicotine exhibited stimulatory effects on the biocontrol efficiency of NXHG29 against bacterial wilt and black shank on tobacco. The stimulatory effect of nicotine was affected by the concentration and timing of nicotine application and further supported by the results of population level of NXHG29 on tobacco roots. This is the first report on the enhancement effect of nicotine from TREs on an antagonistic bacterium for its root colonization, control of soil-borne pathogens, regarding the chemotaxis and in vitro antagonism and growth.

Microwave-assisted synthesis, computational studies and antibacterial/ anti-inflammatory activities of compounds based on coumarin-pyrazole hybrid

An efficient, high-yield and rapid synthesis of (E)-1,5-dimethyl-4-((2-((substituted-2-oxo-2H-chromen-4-yl)methoxy)naphthalen-1-yl)methyleneamino)-2-phenyl-1,2-dihydropyrazol-3-one derivatives (3a-3i) containing Schiff base structures under microwave-irradiation has been described. Schiff base is a potential target to discover anti-inflammatory chemotherapeutics, material science, catalysis and molecular magnetism. All the newly synthesized compounds (3a-3i) have been characterized by elemental analysis and spectroscopic techniques. The synthesized compounds (3a-3i) were evaluated for their antibacterial activity by agar-well diffusion method and anti-inflammatory activity by egg albumin denaturation method. The compounds (3e) and (3i) exhibit antibacterial effect with minimum inhibitory concentration (MIC) 0.78 µg ml^-1 and MIC 1.562 µg ml^-1 against Gram-positive Staphylococcus aureus bacterial strain compared with standard ciprofloxacin drug (MIC 6.25 µg ml^-1). The compounds (3c) and (3f) exhibited an inhibition of heat-induced protein denaturation at the concentration (31.25 µg ml^-1) as 53.65% and 67.27%, respectively, and these compounds are more active than standard aceclofenac drug (5.50%). Molecular docking study has been performed for all the synthesized compounds with S. aureus dihydropteroate synthetase and results obtained are quite promising.

Seed Set and Natural Regeneration of Dendrocalamus membranaceus Munro after Mass and Sporadic Flowering in Yunnan, China

The flowering periods of woody bamboos, seed set, natural regeneration and death after flowering have been rarely observed and evaluated in the field. Dendrocalamus membranaceus Munro, a tropical woody bamboo mainly distributed in the Yunnan, displayed both sporadic as well as gregarious (mass) flowering and fruited from 2006 to 2013 following severe droughts. The aim of this study is to examine potential differences in seed set and natural regeneration between the two flowering patterns in natural D. membranaceus forests. We investigated and analyzed seed set, seed germination, seedling growth and mortality in both mass and sporadic flowering populations. Observations were made over a period of three years to record changes in bamboo seedling density, height and culm diameter. We observed a low natural seed set ranging from 1.76% to 7.49%, and a relatively high seed germination rate in the nursery from 59.6% to 71.0% for both types of flowering populations. Seeds germinated in 5–7 days after sowing and the germination period lasted 10–15 days. Seed set and germination rates in mass-flowering populations were significantly higher than those of sporadically flowering stands. The seedlings within sporadically flowering populations died within two years. In comparison, seedling mortality in the mass flowering population increased over two periods of observation from 64.92% to 98.89%, yet there was good seedling establishment left over, which showed mean height and mean culm diameter increasing by 1053.25% and 410.71%, respectively, in the second year of observations, and 137.10%, and 217.48%, respectively, in the third year. There are significant differences in seed set, natural regeneration ability and sustainability of bamboo populations between the mass flowering and sporadically flowering populations of D. membranaceus. Sporadic flowering populations failed to produce effective regeneration, while mass flowering populations were able to regenerate successfully. This study provides useful insights for conservation and natural forest management of D. membranaceus. We consider the merits of introducing other genetic provenances towards long-term maintenance of the stand features at sporadically flowering sites; meanwhile, the most economic option for mass flowering stands is to allow natural regeneration to take place through protecting such sites from further disturbance.