Arabidopsis phosphatase under-producer mutants <i>pup1</i> and <i>pup3</i> contain mutations in the <i>AtPAP10</i> and <i>AtPAP26</i> genes

<div><p>Production and secretion of acid phosphatases (APases) is a hallmark adaptive response of plants to phosphate (Pi) deprivation. Researchers have long hypothesized that Pi starvation-induced APases are involved in internal Pi recycling and remobilization as well as in external Pi utilization. Two phosphatase under-producer (<i>pup</i>) mutants, <i>pup1</i> and <i>pup3</i>, were previously isolated in <i>Arabidopsis</i>. Characterization of these 2 <i>pup</i> mutants provided the first genetic evidence for the above hypothesis. To date, however, the molecular lesions in these 2 <i>pup</i> mutants remain unknown. In this work, we demonstrate that <i>pup1</i> and <i>pup3</i> contain point mutations in the <i>Arabidopsis</i> purple acid phosphatase gene <i>AtPAP10</i> and <i>AtPAP26</i>, respectively. Our results answer a long-standing question about the molecular identity of the <i>PUP1</i> and <i>PUP3</i> genes and corroborate the conclusions from previous studies regarding the function of AtPAP10 and AtPAP26 in plant acclimation to Pi deprivation.</p></div

Integration of Sentence-Level Semantic Information in Parafovea: Evidence from the RSVP-Flanker Paradigm

<div><p>During text reading, the parafoveal word was usually presented between 2° and 5° from the point of fixation. Whether semantic information of parafoveal words can be processed during sentence reading is a critical and long-standing issue. Recently, studies using the RSVP-flanker paradigm have shown that the incongruent parafoveal word, presented as right flanker, elicited a more negative N400 compared with the congruent parafoveal word. This suggests that the semantic information of parafoveal words can be extracted and integrated during sentence reading, because the N400 effect is a classical index of semantic integration. However, as most previous studies did not control the word-pair congruency of the parafoveal and the foveal words that were presented in the critical triad, it is still unclear whether such integration happened at the sentence level or just at the word-pair level. The present study addressed this question by manipulating verbs in Chinese sentences to yield either a semantically congruent or semantically incongruent context for the critical noun. In particular, the interval between the critical nouns and verbs was controlled to be 4 or 5 characters. Thus, to detect the incongruence of the parafoveal noun, participants had to integrate it with the global sentential context. The results revealed that the N400 time-locked to the critical triads was more negative in incongruent than in congruent sentences, suggesting that parafoveal semantic information can be integrated at the sentence level during Chinese reading.</p></div

Grand average of ERP.

<p>Average EEG waveforms from the onset of the critical triads up to 1200 ms thereafter for congruent condition (black line) and incongruent condition (red line) at 8 representative electrodes, one for each AOI. Negativity is plotted upwards.</p

Forty recorded electrodes and 8 AOIs for ANOVA.

<p>ANT, anterior; CEN, central; POS, posterior; L, left hemisphere; R, right hemisphere.</p

Mean amplitude across conditions in each AOI in the analyzed time window.

<p>Mean amplitude across conditions in each AOI in the analyzed time window.</p

Sentence presentation procedure.

<p>Sentences were presented character by character in the center of the screen, flanked by the previous character to the left and the subsequent character to the right. The context verb was either congruent (<i>picked</i>) or incongruent (<i>captured</i>) with the critical noun (melons) in the sentence. Participants were asked to keep their gaze fixated on the central character and to judge the plausibility of the sentence.</p

Scalp distributions in the analyzed time window.

<p>300~500 ms was the N400 time window evoked by the critical triads and 800~1000 ms was the N400 time window evoked by the post-critical triads.</p

Example sentences with English translations.

<p>Example sentences with English translations.</p

3D Characterization of Human Nano-osseointegration by On-Axis Electron Tomography without the Missing Wedge

Three-dimensional (3D) visualization of bone-implant interfaces via electron tomography (ET) has contributed to the novel perspective of nano-osseointegration and offers evidential support for nanoscaled biomaterial surface modification. Conventional single-axis ET provides a relatively large field of view of the human bone to titanium implant interface showing bone structure arrangement near the interface. However, the “missing wedge” associated with conventional single-axis ET leads to artifacts and elongation in the reconstruction, limiting the resolution and fidelity of reconstructions, as well as the ability to extract quantitative information from nanostructured interfaces. On-axis ET, performed by 180° rotation of a needle-shaped sample, is a promising method to solve this problem. In this work, we present the first application of on-axis ET for investigation of human bone and laser-modified titanium implant interfaces without the missing wedge. This work demonstrates a near artifact-free 3D visualization of the nanotopographies of the implant surface oxide layer and bone growth into these features. Complementary electron energy-loss spectroscopy (EELS) mapping was used to illustrate the gradual intermixing of carbon and calcium (characteristic elements of bone) with the nanoscaled oxide layer of the implant surface. Ultimately, this approach serves as direct evidence of nano-osseointegration and as a potential platform to evaluate differently structured implant surfaces

High-Resolution Visualization of the Osteocyte Lacuno-Canalicular Network Juxtaposed to the Surface of Nanotextured Titanium Implants in Human

Osseointegration is controlled by a number of cellular mechanisms. Although factors governing bone formation are well-understood, the maintenance of bone at the bone-implant interface is less clear. Of some interest is the role of osteocytes, which via mechanotransduction are believed to be responsible for mechanical loading-based remodelling events in bone. Using a resin cast etching technique, we investigated the osteocyte lacuno-canalicular network adjacent to nanostructured titanium human dental implants after four years in clinical function. Correlative electron microscopy showed nanoscale osteocyte processes extending directly onto the implant surface. Calcium signal mapping via electron energy loss spectroscopy (EELS) showed apatite ingrowth into the nanotextured surface, while the apatite platelet <i>c</i>-axis was oriented approximately parallel to the collagen fibril direction. Furthermore, Z-contrast electron tomography demonstrated that natural bone-osteocyte and engineered bone-implant interfaces are similar in ultrastructural morphology. The present ultrastructural observation of multiple connections between osteocyte canaliculi and the nanotextured surface oxide suggests that osteocytes contribute toward the maintenance of osseointegration in long-term clinical function