Transcription factor PbMYB80 regulates lignification of stone cells and undergoes RING finger protein PbRHY1-mediated degradation in pear fruit.

The Chinese white pear (Pyrus bretschneideri) fruit carries a high proportion of stone cells, adversely affecting fruit quality. Lignin is a main component of stone cells in pear fruit. In this study, we discovered that a pear MYB transcription factor, PbMYB80, binds to the promoters of key lignin biosynthesis genes and inhibits their expression. Stable overexpression of PbMYB80 in Arabidopsis showed that lignin deposition and secondary wall thickening were inhibited, and the expression of the lignin biosynthesis genes in transgenic Arabidopsis was decreased. Transient overexpression of PbMYB80 in pear fruit inhibited lignin metabolism and stone cell development, and the expression of some genes in the lignin metabolism pathway was reduced. In contrast, silencing PbMYB80 with VIGS increased the lignin and stone cell content in pear fruit, and increased expression of genes in the lignin metabolism pathway. By screening a pear fruit cDNA library in yeast, we found that PbMYB80 binds to a RING finger (PbRHY1) protein. We also showed that PbRHY1 exhibits E3 ubiquitin ligase activity and degrades ubiquitinated PbMYB80 in vivo and in vitro. This investigation contributes to a better understanding of the regulation of lignin biosynthesis in pear fruit, and provides a theoretical foundation for increasing pear fruit quality at the molecular level.

Risk factors for distal migration of biliary plastic stents and related duodenal injury.

BACKGROUND: The risk factors of duodenal injury from distal migrated biliary plastic stents remain uncertain. The aim of this study was to determine the risk factors of distal migration and its related duodenal injury in patients who underwent placement of a single biliary plastic stent for biliary strictures. METHODS: We retrospectively reviewed all patients with biliary strictures who underwent endoscopic placement of a single biliary plastic stent from January 2006 to October 2017. RESULTS: Two hundred forty-eight patients with 402 endoscopic retrograde cholangiopancreatography procedures were included. The incidence of distal migration was 6.2%. The frequency of duodenal injury was 2.2% in all cases and 36% in cases with distal migration. Benign biliary strictures (BBS), length of the stent above the proximal end of the stricture (> 2 cm), and duration of stent retention (< 3 months) were independently associated with distal migration (p = 0.018, p = 0.009, and p = 0.016, respectively). Duodenal injury occurred more commonly in cases with larger angle (≥ 30°) between the distal end of the stent and the centerline of the patient's body (p = 0.018) or in cases with stent retention < 3 months (p = 0.031). CONCLUSIONS: The risk factors of distal migration are BBS and the length of the stent above the proximal end of the stricture. The risk factor of duodenal injury due to distal migration is large angle (≥ 30°) between the distal end of the stent and the centerline of the patient's body. Distal migration and related duodenal injury are more likely to present during the early period after biliary stenting.

PDA-coated CPT@MIL-53(Fe)-based theranostic nanoplatform for pH-responsive and MRI-guided chemotherapy.

Theranostic nanoplatforms for multimodal diagnosis and treatment of tumors are a current research hotspot in the field of nanomedicine. MOF-based theranostic nanoplatforms integrating drug delivery with magnetic resonance imaging (MRI) have attracted broad attention in cancer diagnosis and therapy. However, due to the poor chemical and colloidal stability of MOFs, as well as their poor biocompatibility, MOF-based theranostic nanoplatforms still face critical challenges in cancer treatment applications. Here, we devised a theranostic nanoplatform based on a bioinspired polydopamine (PDA)-functionalized metal-organic framework MIL-53(Fe) loaded with camptothecin (CPT) for MRI-guided pH-sensitive chemotherapy. On the nanoplatform, MIL-53(Fe) with good biodegradability has large pore volume and showed a high loading content of antitumor drug CPT (43.07%). To overcome the disadvantages of poor aqueous solubility of MIL-53(Fe) and easy photodecomposition of CPT, the CPT-loaded MIL-53(Fe) was coated with a layer of PDA, resulting in theranostic nanoparticles (PDA@CPT@MIL-53(Fe)). The theranostic nanoparticles exhibited excellent stability and pH-sensitive drug release. In vitro toxicity studies showed that the nanoparticles could be efficiently taken up by breast cancer MCF-7 cells and exhibited high cytotoxicity. In vivo antitumor assay showed the great antitumor effect of the theranostic nanoparticles by using a zebrafish xenograft model. Furthermore, the incorporation of Fe affords the PDA@CPT@MIL-53(Fe) with potential MRI; in vitro MRI showed the nanoparticles exhibit an excellent MRI performance with an r2 value up to 50 mM-1 s-1. These results suggest that CPT-loaded MIL-53(Fe) coated with PDA is a promising theranostic platform for MRI imaging and cancer therapy.

Mapping Face Recognition Information Use across Cultures.

Face recognition is not rooted in a universal eye movement information-gathering strategy. Western observers favor a local facial feature sampling strategy, whereas Eastern observers prefer sampling face information from a global, central fixation strategy. Yet, the precise qualitative (the diagnostic) and quantitative (the amount) information underlying these cultural perceptual biases in face recognition remains undetermined. To this end, we monitored the eye movements of Western and Eastern observers during a face recognition task, with a novel gaze-contingent technique: the Expanding Spotlight. We used 2° Gaussian apertures centered on the observers' fixations expanding dynamically at a rate of 1° every 25 ms at each fixation - the longer the fixation duration, the larger the aperture size. Identity-specific face information was only displayed within the Gaussian aperture; outside the aperture, an average face template was displayed to facilitate saccade planning. Thus, the Expanding Spotlight simultaneously maps out the facial information span at each fixation location. Data obtained with the Expanding Spotlight technique confirmed that Westerners extract more information from the eye region, whereas Easterners extract more information from the nose region. Interestingly, this quantitative difference was paired with a qualitative disparity. Retinal filters based on spatial-frequency decomposition built from the fixations maps revealed that Westerners used local high-spatial-frequency information sampling, covering all the features critical for effective face recognition (the eyes and the mouth). In contrast, Easterners achieved a similar result by using global low-spatial-frequency information from those facial features. Our data show that the face system flexibly engages into local or global eye movement strategies across cultures, by relying on distinct facial information span and culturally tuned spatially filtered information. Overall, our findings challenge the view of a unique putative process for face recognition.

Putting culture under the 'spotlight' reveals universal information use for face recognition.

BACKGROUND: Eye movement strategies employed by humans to identify conspecifics are not universal. Westerners predominantly fixate the eyes during face recognition, whereas Easterners more the nose region, yet recognition accuracy is comparable. However, natural fixations do not unequivocally represent information extraction. So the question of whether humans universally use identical facial information to recognize faces remains unresolved. METHODOLOGY/PRINCIPAL FINDINGS: We monitored eye movements during face recognition of Western Caucasian (WC) and East Asian (EA) observers with a novel technique in face recognition that parametrically restricts information outside central vision. We used 'Spotlights' with Gaussian apertures of 2 degrees, 5 degrees or 8 degrees dynamically centered on observers' fixations. Strikingly, in constrained Spotlight conditions (2 degrees and 5 degrees) observers of both cultures actively fixated the same facial information: the eyes and mouth. When information from both eyes and mouth was simultaneously available when fixating the nose (8 degrees), as expected EA observers shifted their fixations towards this region. CONCLUSIONS/SIGNIFICANCE: Social experience and cultural factors shape the strategies used to extract information from faces, but these results suggest that external forces do not modulate information use. Human beings rely on identical facial information to recognize conspecifics, a universal law that might be dictated by the evolutionary constraints of nature and not nurture.