Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense, is one of the most serious diseases of banana. F. oxysporum f. sp. cubense race 1 (Foc1) and race 4 (Foc4) are the most prevalent pathogens of banana cultivars in the world. To understand the differences in the infection processes between Foc1 and Foc4, green fluorescent protein-tagged strains of F. oxysporum f. sp. cubense tropical race 4 (FocTR4) and Foc1 were used to inoculate ‘Brazil Cavendish’ banana. At 2 days postinoculation (dpi), it was observed that the spores and hyphae of both Foc1 and Foc4 attached to the root hairs and root epidermis. At 3 dpi, the hyphae of both Foc1 and Foc4 were found in the vascular tissues of roots. However, Foc4 was observed in the parenchymal cells of banana root, whereas Foc1 was not found in parenchymal cells at 7 dpi. Furthermore, few Foc1 hyphae were observed in a few xylems whereas many more Foc4 hyphae were present in many xylems and phloems. Foc4 was observed in the vascular tissues of banana rhizomes, whereas no Foc1 was found in rhizomes 2 months after inoculation. The attachment process in F. oxysporum f. sp. cubense infection was further studied with scanning electron microscopy. Foc4 was observed to penetrate into banana roots from the intercellular space of the epidermis and wounds, whereas Foc1 mainly penetrated from the wounds but not from the intercellular space of the epidermis. Therefore, direct root penetration and rhizome vascular colonization by F. oxysporum f. sp. cubense are the key steps in the successful infection of Brazil Cavendish.

As fundamental components in innate immunity, antimicrobial peptides (AMPs) hold great potentials in the treatment of persistent infections involving slow-growing or dormant bacteria in which, selective inhibition of prokaryotic bacteria in the context of eukaryotic cells is not only an essential requirement, but also a critical challenge in the development of antimicrobial peptides. To identify the sequence and structural properties critical for antimicrobial activity, a series of peptides varying in sequence, length, hydrophobicity/charge ratio, and secondary structure, were designed and synthesized. Their antimicrobial activities were then tested using Escherichia coli and HEK293 cells, together with several index activities against model membrane, including liposome leakage, fusion, and aggregation. While no evident correlation between the antimicrobial activity and the property of the peptides was observed, common activities against model membrane were nevertheless identified for the active antimicrobial peptides: mediating efficient membrane leakage, negligible membrane fusion and liposome aggregation. Therefore, in addition to identifying one highly active antimicrobial peptide, our study further sheds light on the design principle for these molecules.

Biological membranes are heterogeneous systems. Their functions are closely related to the lipid lateral segregation in the presence of membrane proteins. In this work, we designed two peptides, amphiphilic cationic peptides K3L8K3 and nonamphiphilic peptides K20, and studied their interactions with binary liposomes in different phases (Lα, Lβ', and Lα/Lβ'). As mimics of membrane proteins, both K3L8K3 and K20 can cause the liposomes to aggregate, fuse, or leak. These processes were closely related to the phases of liposomes. For the liposomes in Lα phase, heavy aggregation, fusion, and leakage were observed in the presence of either K20 or K3L8K3. For the liposomes in Lβ' phase, neither K3L8K3 nor K20 can induce fusion or leakage. For the liposomes in Lα/Lβ' phase, K3L8K3 caused the liposomes to aggregate, fuse, and leak, while K20 only led to aggregation. The kinetics of aggregation, fusion, and leakage in each phase were recorded, and they were related to the lipid demixing in the presence of the peptide. Our work not only gained insight into the effect of the lipid demixing on the interactions between peptide and membrane, but also helped in developing drug delivery vehicles with liposomes as the platform.

Distinguishing driver mutations from passenger mutations is critical to the understanding of the molecular mechanisms of carcinogenesis and for identifying prognostic and diagnostic markers as well as therapeutic targets. We reviewed the current approaches and software for identifying driver mutations from passenger mutations including both biology-based approaches and machine-learning-based approaches. We also reviewed approaches to identify driver mutations in the context of pathways or gene sets. Finally, we discussed the challenges of predicting driver mutations considering the complexities of inter- and intra-tumor heterogeneity as well as the evolution and progression of tumors.

A series of photoresponsive dendronized polymers PGn-NB (n = 1, 2, 3) were synthesized by attaching o-nitrobenzyl alcohol-terminated amidoamine dendrons (G1–G3) to the alternating styrene and maleic anhydride copolymer (PSt-alt-PMAh). The structures and the molecular weights of the obtained polymers were characterized by 1H NMR and FTIR measurements. It is found that the coverage degrees of the dendrons are 74%, 42%, and 26%, respectively, indicating that the numbers of the appended dendrons decrease in the order of G1 > G2 > G3 due to the steric hindrance of higher generation dendrons with more branches. The photocleavable behavior of G1–G3 was detected by UV–vis and 1H NMR measurements. As a result, G2 showed a faster cleavage rate compared to G1 and G3. The critical aggregation concentration (CAC) of PGn-NB (n = 1, 2, 3), measured by using pyrene as a fluorescence probe, were 0.05 mg/mL (PG1-NB), 0.01 mg/mL (PG2-NB), and 0.03 mg/mL (PG3-NB), which displayed that the structure of PG2-NB was in favor of forming aggregates at lower concentrations. Light scattering study indicated that both the apparent molecular weight and the chain density of the aggregates formed by PG2-NB decreased with the irradiation time. Atomic force microscope (AFM) measurements also showed that the size of the aggregates increased dramatically from 15 to 70 nm before and after UV irradiation, evidencing that the UV light induced structure change. Nile Reds, as the guest molecules, were loaded in the aggregates from PG2-NB, and the release profiles upon UV stimulus were monitored by the fluorescence spectroscopy.

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Excessive nitrogen (N) application is widespread in Southern China. The effects of N fertilization on soil properties and crop physiology are poorly understood in tropical red loam soil. We conducted a field experiment to evaluate the effect of nitrogen fertilization rates on physiological attributes (chlorophyll, plant metabolic enzymes, soluble matters) on banana leaves, soil properties (soil enzymes, soil organic matter (SOM), soil available nutrients) as well as banana crop yield in a subtropical region of southern China. The N rates tested were 0 (N0), 145 (N145), 248 (N248), 352 (N352), 414 (NFT), and 455 (N455) g N per plant. The correlations among soil factors, leaf physiological factors and crop yield were evaluated. The results indiated that the high rates of N fertilization (NFT and N455) significantly decreased soil available potassium (K) content, available phosphorus (P) content, glutamine synthetase (GS) activity, and soluble protein and sugar contents compared with lower N rates. The N352 treatment had the highest crop yields compared with higher N rates treatments, followed by the N455 treatment. However, there were no significant differences in crop yields among N fertilization treatments. Factor analysis showed that the N352 treatment had the highest integrated score for soil and leaf physiological factors among all treatments. Moreover, the N352 treatment was the most effective in improving carbon and nitrogen metabolism in banana. Crop yield was significantly and positively linearly correlated with the integrated score (r = 0.823, p < 0.05). Path analysis revealed that invertase, SOM and sucrose synthase (SS) had a strong positive effect on banana yield. Canonical correspondence analysis (CCA) suggested that available K, invertase, acid phosphatase and available P were the most important factors impacting leaf physiological attributes. Cluster analysis demonstrated distinct differences in N application treatment related to variations in soil and leaf factors. This study suggested that excessive N fertilization had a negative effect on soil fertility, crop physiology and yield. The lower N rates were more effective in improving crop yield than higher rates of N fertilization. The N rate of 352 g N per plant (N352) was recommended to reduce excess N input while maintaining the higher yield for local farmers’ banana planting.