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Plant organ growth and final shape rely on cell proliferation and, particularly, on cell expansion that largely determines the visible growth of plant organs. Arabidopsis (Arabidopsis thaliana) petals serve as an excellent model for dissecting the coordinated regulation of patterns of cell expansion and organ growth, but the molecular signaling mechanisms underlying this regulation remain largely unknown. Here, we demonstrate that during the late petal development stages, SPIKE1 (SPK1), encoding a guanine nucleotide exchange factor, activates Rho of Plants (ROP) GTPase proteins (ROP2, ROP4, and ROP6) to affect anisotropic expansion of epidermal cells in both petal blades and claws, thereby affecting anisotropic growth of the petal and the final characteristic organ shape. The petals of SPK1 knockdown mutants were significantly longer but narrower than those of the wild type, associated with increased anisotropic expansion of epidermal cells at late development stages. In addition, ROP2, ROP4, and ROP6 are activated by SPK1 to promote the isotropic organization of cortical microtubule arrays and thus inhibit anisotropic growth in the petal. Both knockdown of SPK1 and multiple rop mutants caused highly ordered cortical microtubule arrays that were transversely oriented relative to the axis of cell elongation after development stage 11. Taken together, our results suggest a SPK1-ROP-dependent signaling module that influences anisotropic growth in the petal and defines the final organ shape.

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This study is to investigate the subgingival bacterial diversity and community structure in the Uygur subjects with peri-implantitis.Totally 40 cases of gingival crevicular fluid were collected from Uygur subjects and divided into the Control group (healthy implants) and Case group (peri-implantitis), respectively. DNA was extracted, and the sequencing in the 16SrRNA V4-V5 region was conducted on the Illumina Miseq sequencing platform. The 16SrRNA gene clone library was constructed and analyzed.Totally 733,759 valid tags were obtained from these 40 samples. After comparing with the Silva-16S database by the Uparse software, 263 operational taxonomic unit were finally harvested (135 for the Control group and 128 for the Case group). The differential bacteria between these 2 groups at the phylum, class, order, family, and genus levels were Actinobacteria, Actinomycetes, Pasteurellales, Moraxellaceae, and Acinetobacter, respectively. The dominant genera with significantly different distribution between the Control and Case groups included Vibrio, Campylobacter, Granulicatella, Acinetobacter, Micrococcus, and Moraxella. The α diverstiy analysis based on the chao diversity index showed that there was significant difference in the microbiological diversity between these 2 groups. Principal coordinates analysis analysis indicated significant differences in the bacterial community structure between these 2 groups. Cluster analysis showed higher abundance of Micrococcus in the Case group, while higher abundance of Prevotella in the Control group.There are significant differences in the diversity of subgingival bacteria between the Uygur subjects with healthy implants and peri-implantitis. Moraxella, Micrococcus, and Acinetobacter might represent dominant bacteria genera causing peri-implantitis in the Uygur population.

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Polar auxin transport, which is required for the formation of auxin gradients and directional auxin flows that are critical for plant pattern formation, morphogenesis, and directional growth response to vectorial cues, is mediated by polarized sub-cellular distribution of PIN-FORMED Proteins (PINs, auxin efflux carriers), AUX1/AUX1-like proteins (auxin influx facilitators), and multidrug resistance P-glycoproteins (MDR/PGP). Polar localization of these proteins is controlled by both developmental and environmental cues. Recent studies have revealed cellular (endocytosis, transcytosis, and endosomal sorting and recycling) and molecular (PINOID kinase, protein phosphatase 2A) mechanisms underlying the polar distribution of these auxin transport proteins. Both TIR1-mediated auxin signaling and TIR1-independent auxin-mediated endocytosis have been shown to regulate polar PIN localization and auxin flow, implicating auxin as a self-organizing signal in directing polar transport and directional flows.

The oral microbiome has major impacts on oral health and disease. Antimicrobial peptides (AMPs), such as nisin and cecropin, have been widely used as food preservatives or feed additives, and are thus inevitably ingested by consumers through their oral cavity. However, as broad-spectrum antimicrobial reagents, the effect of AMPs on the oral microbiome of consumer's remains poorly characterized. In this study, we performed 16S rDNA high-throughput sequencing to investigate the effect of nisin and cecropin on the oral microbiomes of rats. Our results suggest that although nisin and cecropin have different effects on the oral microbiome of rats, both AMPs impact the composition of oral microbial communities at the phylum and genus levels. Cecropin significantly reduced the diversity and richness of rat oral microbial communities. Notably, the relative abundance of the pathogen Acinetobacter baumannii increased in the oral microbial community of rats fed cecropin-containing feed. In addition, nisin significantly reduced the amount of secretory immunoglobulin A in the saliva of rats.