Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the ...genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce).
Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed.
The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer.
Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen.
Two skeleton isomers, CaL(H2O)(DMF)2•DMF (1) (H2L=5‐(1,3‐dioxo‐1H‐benzodeisoquinolin‐2(3H)‐yl)isophthalic acid) with a 1 dimensional chain structure and CaL(DMF)1.72• (DMF)0.28 (2) with a 2 ...dimensional layer structure were synthesized. Mechanochromic luminescence studies reveal that 1 and 2 exhibit luminescent red‐shift and blue‐shift respectively under grinding stimuli. The different influence of grinding stimuli on the π⋅⋅⋅π interaction in the two structures are proposed to be the main reason for such different responses. In addition, 1 has a rare broad sensing ability for halogenated hydrocarbons and can distinguish seven halogenated hydrocarbons out of 17 solvents. 1 can also be used for rapid detection of trace water in DMF with a calculated detection limit of 0.0078 v/v %. The relevant recognition mechanism is the decomposition of the structure during the recognition process due to the water instability of the ionic bond. The above results reveal that both compounds have the potential to be used as multi‐stimulus‐responsive materials.
Present here are two framework isomers that exhibit grinding and volatile organic solvent stimulus response properties. In addition, one can also be used to detect H2O in DMF with detection limit of 0.0078 v/v%.
Summary
Glycoside hydrolase 12 (GH12) proteins act as virulence factors and pathogen‐associated molecular patterns (PAMPs) in oomycetes. However, the pathogenic mechanisms of fungal GH12 proteins ...have not been characterized. In this study, we demonstrated that two of the six GH12 proteins produced by the fungus Verticillium dahliae Vd991, VdEG1 and VdEG3 acted as PAMPs to trigger cell death and PAMP‐triggered immunity (PTI) independent of their enzymatic activity in Nicotiana benthamiana. A 63‐amino‐acid peptide of VdEG3 was sufficient for cell death‐inducing activity, but this was not the case for the corresponding peptide of VdEG1. Further study indicated that VdEG1 and VdEG3 trigger PTI in different ways: BAK1 is required for VdEG1‐ and VdEG3‐triggered immunity, while SOBIR1 is specifically required for VdEG1‐triggered immunity in N. benthamiana. Unlike oomycetes, which employ RXLR effectors to suppress host immunity, a carbohydrate‐binding module family 1 (CBM1) protein domain suppressed GH12 protein‐induced cell death. Furthermore, during infection of N. benthamiana and cotton, VdEG1 and VdEG3 acted as PAMPs and virulence factors, respectively indicative of host‐dependent molecular functions. These results suggest that VdEG1 and VdEG3 associate differently with BAK1 and SOBIR1 receptor‐like kinases to trigger immunity in N. benthamiana, and together with CBM1‐containing proteins manipulate plant immunity.
Two conceptual convolutional neural network (CNN) schemes are proposed, developed and analysed for directly decoding nonlinear frequency division multiplexing (NFDM) signals with hardware ...implementation taken into consideration. A serial network scheme with a small network size is designed for small user applications, and a parallel network scheme with high speed is designed for places such as data centres. The work aimed at showing the potential of using CNN for practical NFDM-based fibre optic communication. In the numerical demonstrations, the serial network only occupies 0.5 MB of memory space while the parallel network occupies 128 MB of memory but allows parallel computing. Both network schemes were trained with simulated data and reached more than 99.9% accuracy.
Summary
Fungal transcription factors (TFs) implicated in the regulation of virulence gene expression have been identified in a number of plant pathogens. In Verticillium dahliae, despite its ...agricultural importance, few regulators of transcription have been characterized. In this study, a T‐DNA insertion mutant with significantly reduced virulence towards cotton was identified. The T‐DNA was traced to VdFTF1, a gene encoding a TF containing a Fungal_trans domain. Transient expression in onion epidermal cells indicated that VdFTF1 is localized to the nucleus. The VdFTF1‐deletion strains displayed normal vegetative growth, mycelial pigmentation and conidial morphology, but exhibited significantly reduced virulence on cotton, suggesting that VdFTF1 is required exclusively for pathogenesis. Comparisons of global transcription patterns of wild‐type and VdFTF1‐deletion strains indicated that VdFTF1 affected the expression of 802 genes, 233 of which were associated with catalytic processes. These genes encoded 69 potentially secreted proteins, 43 of which contained a carbohydrate enzyme domain known to participate in pathogenesis during infection of cotton. Targeted gene deletion of one VdFTF1‐regulated gene resulted in significantly impaired vascular colonization, as measured by quantitative polymerase chain reaction, as well as aggressiveness and symptom severity in cotton. In conclusion, VdFTF1, which encodes a TF containing a Fungal_trans domain, regulates the gene expression of plant cell wall degradation enzymes in V. dahliae, which are required for full virulence on cotton.
A series of pleuromutilin derivatives containing alkylamine and nitrogen heterocycle groups were designed and synthesised under mild conditions. The in vitro antibacterial activity of these ...semisynthetic derivatives against four strains of Staphylococcus aureus (MRSA ATCC 43300, S.aureus ATCC 29213, S.aureus AD3, and S.aureus 144) were evaluated by the broth dilution method. Compound 13 was found to have excellent antibacterial activity against MRSA (MIC = 0.0625 μg/mL). Furthermore, compound 13 was further studied by the time-killing kinetics and the post-antibiotic effect approach. In the mouse thigh infection model, compound 13 exhibited superior antibacterial efficacy than that of tiamulin. Meanwhile, compound 13 showed a lower inhibitory effect than that of tiamulin on RAW264.7 and 16HBE cells at the concentration of 10 μg/mL. Molecular docking study revealed that compound 13 can effectively bind to the active site of the 50S ribosome (the binding free energy = −9.66 kcal/mol).
Comprehensive Summary
Cell‐free expression systems have emerged as a versatile and powerful platform for metabolic engineering, biosynthesis and synthetic biology studies. Nevertheless, successful ...examples of the synthesis of complex natural products using this system are still limited. Bicyclomycin, a structurally unique and complex diketopiperazine alkaloid, is a clinically promising antibiotic that selectively inhibits the transcription termination factor Rho. Here, we established a modular cell‐free expression system with cascade catalysis for the biosynthesis of bicyclomycin from a chemically synthesized cyclodipeptide. The six cell‐free expressed biosynthetic enzymes, including five iron‐ and α‐ketoglutarate‐dependent dioxygenases and one cytochrome P450 monooxygenase, were active in converting their substrates to the corresponding products. The co‐expressed enzymes in the cell‐free module were able to complete the related partial pathway. In vitro biosynthesis of bicyclomycin was also achieved by reconstituting the entire biosynthetic pathways (i.e., six enzymes) using the modular cell‐free expression system. This study demonstrates that the modular cell‐free expression system can be used as a robust and promising platform for the biosynthesis of complex antibiotics.
A modular cell‐free expression system was established for the biosynthesis of bicyclomycin from a chemically synthesized cyclodipeptide.
Carbon content constitutes a major fraction of atmospheric particulate matter (PM) and directly influences the earth’s climate and human health. The stable carbon isotope ratios (δ13C) can be used to ...track potential sources and atmospheric processes of carbonaceous aerosols. Previously, determination of δ13C was always conducted in offline carbonaceous aerosol samples. The poor time-resolution results cannot provide information regarding the temporal evolution of δ13C at a short-time scale. In this study, we developed a new system for online measurements of δ13C in atmospheric carbonaceous aerosols by combining a semicontinuous organic carbon/elemental carbon (OC/EC) analyzer and online cavity ring-down spectroscopy (CRDS) (OC/EC analyzer-CRDS). To provide better stability in the determination of δ13C, a carrier gas with CO2 (∼200 ppm) in “balance gas” was used, and Keeling analysis was employed to separate the δ13C signal of the sample from background CO2 gas. Our results showed that the accuracy and absolute precision of the δ13C measurements by the OC/EC analyzer-CRDS system were better than 0.1‰ and 0.5‰, respectively, for the samples containing carbon content more than 5 μg. Furthermore, we employed this system to monitor δ13C (δ13C-TC) in particulate total carbon (TC) with a time resolution of 2–4 h over Beijing in late summer and early autumn, 2019. During the sampling period, the TC concentrations varied from 0.1 to 12.0 μg m–3 with a mean value of 6.0 ± 2.4 μg m–3. The δ13C-TC ranged from −28.2 to −24.2‰ (mean value was −25.9 ± 0.9‰) without significant diurnal variations, suggesting similar contributing sources to TC. Comparing the δ13C signatures of different emissions, we found that liquid fuels and primary and secondary C3 plants were likely the dominant sources of particulate TC. Finally, we found that atmospheric heavy precipitation washed out the aged aerosols from the polluted air, resulting in significant depletion (∼2.4‰) of δ13C-TC in the atmosphere. This paper described a novel system for conducting online measurements of δ13C in atmospheric carbonaceous aerosols and provided us information to better understand the temporal evolution of emission sources and atmospheric processes of carbonaceous aerosols.
A series of pleuromutilin derivatives containing benzimidazole were designed, synthesized, and evaluated for their antibacterial activities against Methicillin-resistant Staphylococcus aureus (MRSA) ...in this study. The in vitro antibacterial activities of the synthesized derivatives against four strains of S. aureus (MRSA ATCC 43300, S. aureus ATCC 29213, S. aureus 144, and S. aureus AD3) were determined by the broth dilution method. Among these derivatives, compound 58 exhibited superior in vitro antibacterial effect against MRSA (minimal inhibitory concentration MIC = 0.0625 μg/mL) than tiamulin (MIC = 0.5 μg/mL). Compound 58 possessed a faster bactericidal kinetic and a longer post-antibiotic effect time against MRSA than tiamulin. Meanwhile, at 8 μg/mL concentration, compound 58 did not display obviously cytotoxic effect on the RAW 264.7 cells. In addition, compound 58 (-2.04 log
CFU/mL) displayed superior in vivo antibacterial efficacy than tiamulin (-1.02 log
CFU/mL) in reducing MRSA load in mice thigh infection model. In molecular docking study, compound 58 can successfully attach to the 50S ribosomal active site (the binding free energy is -8.11 kcal/mol). Therefore, compound 58 was a potential antibacterial candidate for combating MRSA infections.
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