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Cyclic peptide natural products represent an important class of bioactive compounds and clinical drugs. Enzymatic side-chain macrocyclization of ribosomal peptides is a major strategy developed by nature to generate these chemotypes, as exemplified by the superfamily of ribosomally synthesized and post-translational modified peptides. Despite the diverse types of side-chain crosslinks in this superfamily, the participation of histidine residues is rare. Herein, we report the discovery and biosynthesis of bacteria-derived tricyclic lanthipeptide noursin, which is constrained by a tri amino acid labionin crosslink and an unprecedented histidine-to-butyrine crosslink, named histidinobutyrine. Noursin displays copper-binding ability that requires the histidinobutyrine crosslink and represents the first copper-binding lanthipeptide. A subgroup of lanthipeptide synthetases, named LanKC Hbt , were identified to catalyze the formation of both the labionin and the histidinobutyrine crosslinks in precursor peptides and produce noursin-like compounds. The discovery of the histidinobutyrine-containing lanthipeptides expands the scope of post-translational modifications, structural diversity and bioactivity of ribosomally synthesized and post-translational modified peptides. Cyclic peptides are important bioactive compounds and drugs, synthesised by enzymatic side-chain macrocyclization of ribosomal peptides, which rarely involves histidine residues. Here, the authors report the discovery and biosynthesis of tricyclic lanthipeptide noursin, constrained by a tri amino acid labionin crosslink and histidine-to-butyrine crosslink, which is important for copper binding of noursin.

Most cellular solids presented random structure, while practically periodic models were often used in structure-property relations and numerical models. The finite element method was used to create a 2D random model that replicated the deformation characteristics of cellular models. The influences of porosity and strain rate on the deformation characteristic, energy dissipation mechanisms were investigated. The Poisson’s ratio evolution during compression was also studied. The simulated load-displacement curves were found to be consistent with experimental results, both containing elastic stage, plateau stage, hardening stage and densification stage. The yield load and plateau load were insensitive to the strain rate. In addition, it was also found that the generation and propagation of multiple random shear bands were responsible for the load-displacement characteristic. At the cell/membrane level, four failure modes and corresponding energy dissipation mechanisms were revealed. Moreover, the Poisson’s ratio decreased first and then increased with strain, which right manifested the compressibility of 2D foam in the initial stage and the densification in the end of compression. Meanwhile, the change of the Poisson’s ratio with porosity didn’t follow monotone function relation.

The drop hammer impact test was carried out to investigate the dynamic response of closed-cell Al foams. A relatively reasonable method was also developed to evaluate the velocity sensitivity of cellular material. The typical impact load–displacement curve exhibited two stages containing the initial compression stage and the progressive crushing stage. Three compressive damage behaviors and four failure modes of closed-cell Al foams were revealed, while the effect of velocity on the impact properties and the energy absorption capacity of different specimens were investigated. The results showed that the specific energy absorption of the specimens increased with the increasing density of the specimen and the impact velocity. However, the specimens with higher specific energy absorption seemed not to indicate better cushioning performance due to the shorter crushing displacement. In addition, the uniaxial impact simulation of two-dimensional (2D) Voronoi-based foam specimens was conducted at higher impact velocities. The simulation results of impact properties and deformation behavior agreed reasonably well with the experimental results, exhibiting similar velocity insensitivity of peak loads and deformation morphologies during uniaxial impact.

Clausena lansium (Lour.) Skeels seeds have been shown to have diverse beneficial medical value due to their unique active components. This study analysed the composition of essential oils (EOs) of C. lansium seeds and investigated their potential antifungal effects against Candida strains . A total of forty-six components were identified in all samples by gas chromatography-mass spectrometry (GC–MS). The main components were sabinene, β -phellandrene and 4-terpineol. Thirteen EOs of C. lansium seeds were classified into three clusters based on their components. Cluster analysis showed that the difference between the tropics and subtropics was the greatest. These EOs and the three main chemicals showed different antifungal activities against five Candida species ( C. albicans , C. tropicalis , C. glabrata , C. krusei and C. parapsilosis ). The antifungal activity against C. glabrata and C. krusei was higher than that against other Candida strains. EOs of C. lansium seeds displayed noteworthy antifungal activity against both sensitive and fluconazole-resistant strains, with inhibition zone diameters in the range of 9.4–23.4 mm. Comprehensive analysis illustrated the importance of sabinene, β -phellandrene and 4-terpineol to antifungal activity, and there may be some synergistic effects with other components. These results represent the first report about the correlation between the chemical composition of EOs of C. lansium seeds and antifungal activity. Taken together, the results obtained provide scientific evidence for the traditional use of C. lansium seeds waste.

The recent advent of single-cell RNA sequencing (scRNA-seq) has enabled access to the developmental landscape of a complex organ by monitoring the differentiation trajectory of every specialized cell type at the single-cell level. A main challenge in this endeavor is dissociating plant cells from the rigid cell walls and some species are recalcitrant to such cellular isolation. Here, we describe the establishment of a simple and efficient protocol for protoplast preparation in Chirita pumila, which includes two consecutive digestion processes with different enzymatic buffers. Using this protocol, we generated viable cell suspensions suitable for an array of expression analyses, including scRNA-seq. The universal application of this protocol was further tested by successfully isolating high-quality protoplasts from multiple organs (petals, fruits, tuberous roots, and gynophores) from representative species on the key branches of the angiosperm lineage. This work provides a robust method in plant science, overcoming barriers to isolating protoplasts in diverse plant species and opens a new avenue to study cell type specification, tissue function, and organ diversification in plants.

Point cloud classification is a key technology for point cloud applications and point cloud feature extraction is a key step towards achieving point cloud classification. Although there are many point cloud feature extraction and classification methods, and the acquisition of colored point cloud data has become easier in recent years, most point cloud processing algorithms do not consider the color information associated with the point cloud or do not make full use of the color information. Therefore, we propose a voxel-based local feature descriptor according to the voxel-based local binary pattern (VLBP) and fuses point cloud RGB information and geometric structure features using a random forest classifier to build a color point cloud classification algorithm. The proposed algorithm voxelizes the point cloud; divides the neighborhood of the center point into cubes (i.e., multiple adjacent sub-voxels); compares the gray information of the voxel center and adjacent sub-voxels; performs voxel global thresholding to convert it into a binary code; and uses a local difference sign–magnitude transform (LDSMT) to decompose the local difference of an entire voxel into two complementary components of sign and magnitude. Then, the VLBP feature of each point is extracted. To obtain more structural information about the point cloud, the proposed method extracts the normal vector of each point and the corresponding fast point feature histogram (FPFH) based on the normal vector. Finally, the geometric mechanism features (normal vector and FPFH) and color features (RGB and VLBP features) of the point cloud are fused, and a random forest classifier is used to classify the color laser point cloud. The experimental results show that the proposed algorithm can achieve effective point cloud classification for point cloud data from different indoor and outdoor scenes, and the proposed VLBP features can improve the accuracy of point cloud classification.

Members of the CYCLOIDEA2 (CYC2) clade of the TEOSINTE BRANCHED1, CYCLOIDEA, and PCF transcription factor genes are widely involved in controlling floral zygomorphy, a key innovation in angiosperm evolution, depending on their persistently asymmetric expression in the corresponding floral domains. However, it is unclear how this asymmetric expression is maintained throughout floral development. Selecting Primulina heterotricha as a model, we examined the expression and function of two CYC2 genes, CYC1C and CYC1D. We analyzed the role of their promoters in protein-DNA interactions and transcription activation using electrophoresis mobility shift assays, chromatin immunoprecipitation, and transient gene expression assays. We find that CYC1C and CYC1D positively autoregulate themselves and cross-regulate each other. Our results reveal a double positive autoregulatory feedback loop, evolved for a pair of CYC2 genes to maintain their expression in developing flowers. Further comparative genome analyses, together with the available expression and function data of CYC2 genes in the core eudicots, suggest that this mechanism might have led to the independent origins of floral zygomorphy, which are associated with plant-insect coevolution and the adaptive radiation of angiosperms.

Background Great advances have been achieved in our understanding of flower development and evolution since the establishment of the ABC model. However, it remains a challenge to define the exact context of organ identity in the component interactions of the ABC model. Results Through hybridization, we detected a homeotic mutant in Petrocosmea (Gesneriaceae) uniquely displayed by the ‘petaloid-stamen’ in the third whorl with petal identity. Comparative Real-time PCR analyses demonstrate that both two B-class genes DEF2 and GLO are excessively expressed while the transcripts of the C-class gene PLE are reduced in the third floral whorl in the mutant compared to that in the wild-type F 1 hybrids. Further allele-specific expression (ASE) analyses indicate that an allele-specific change in PgPLE might be responsible for up-regulation of both B-class genes and down-regulation of the C-class gene in the petaloid-stamen mutants. Conclusions Our findings suggest that the petaloid-stamen is consequent upon an evident dosage imbalance between B- and C-class products that is probably triggered by a cis -regulatory change. In addition, the genetic pathway for the floral organ identity might be in parallel with that for the floral symmetry. The extreme variation in hybrids further suggests that interspecific hybridization may represent a major factor for evolutionary innovation and diversification in plants.

Accurate classification systems based on evolution are imperative for biological investigations. The recent explosion of molecular phylogenetics has resulted in a much improved classification of angiosperms. More than five phylogenetic lineages have been recognized from Scrophulariaceae sensu lato since the family was determined to be polyphyletic; however, questions remain about the genera that have not been assigned to one of the segregate families of Scrophulariaceae s.l. Rehmannia Liboschitz and Triaenophora Solereder are such genera with uncertain familial placement. There also is debate whether Triaenophora should be segregated from Rehmannia. To evaluate the phylogenetic relations between Rehmannia and Triaenophora, to find their closest relatives, and to verify their familial placement, we conducted phylogenetic analyses of the sequences of one nuclear DNA (ITS) region and four chloroplast DNA gene regions (trnL-F, rps16, rbcL, and rps2) individually and combined. The analyses showed that Rehmannia and Triaenophora are each strongly supported as monophyletic and together are sister to Orobanchaceae. This relation was corroborated by phytochemical and morphological data. Based on these data, we suggest that Rehmannia and Triaenophora represent the second nonparasitic branch sister to the remainder of Orobanchaceae (including Lindenbergia).

An efficient transformation and regeneration system is essential for functional investigation of developmental genes and related elements in the field of evolutionary developmental biology (evo-devo). Chirita pumila D. Don belongs to the Gesneriaceae family, one of the most basal groups in Lamiales sensu lato, and possesses many tractable biological features including annual habit, small plant size, short generation time, abundant offspring and low chromosome number. In addition, C. pumila has cleistogamous flowers with potential cross-pollination, a special phenomenon first reported herein in Gesneriaceae. Parameters affecting shoot induction and genetic transformation have been evaluated, including plant growth regulators, temperature, antibiotic concentration, pre- and co-culture duration, Agrobacterium cell density and infection time. Polymerase chain reaction and β-Glucuronidase (GUS) activity assays of T0 and T1 plants show that the GUS gene has been introduced into the host with stable and universal expression. The applicability of the transformation system in gene function investigation is further confirmed by transforming a GsNST1B gene from Glycine soja. This transformation system provides a valuable platform for deep function analyses of related genes and elements for a wide range of evo-devo studies, especially in the field of floral evolution, which would develop its potential of being a model organism in Lamiales s. l.