Many multicellular organisms have remarkable capability to regenerate new organs after wounding. As a first step of organ regeneration, adult somatic cells often dedifferentiate to reacquire cell proliferation potential, but mechanisms underlying this process remain unknown in plants. Here we show that an AP2/ERF transcription factor, WOUND INDUCED DEDIFFERENTIATION 1 (WIND1), is involved in the control of cell dedifferentiation in Arabidopsis. WIND1 is rapidly induced at the wound site, and it promotes cell dedifferentiation and subsequent cell proliferation to form a mass of pluripotent cells termed callus. We further demonstrate that ectopic overexpression of WIND1 is sufficient to establish and maintain the dedifferentiated status of somatic cells without exogenous auxin and cytokinin, two plant hormones that are normally required for cell dedifferentiation. In vivo imaging of a synthetic cytokinin reporter reveals that wounding upregulates the B-type ARABIDOPSIS RESPONSE REGULATOR (ARR)-mediated cytokinin response and that WIND1 acts via the ARR-dependent signaling pathway to promote cell dedifferentiation. This study provides novel molecular insights into how plants control cell dedifferentiation in response to wounding.

Neat1 is a non-protein-coding RNA that serves as an architectural component of the nuclear bodies known as paraspeckles. Although cell-based studies indicate that Neat1 is a crucial regulator of gene expression, its physiological relevance remains unclear. Here, we find that Neat1 knockout (KO) mice stochastically fail to become pregnant despite normal ovulation. Unilateral transplantation of wild-type ovaries or the administration of progesterone partially rescued the phenotype, suggesting that corpus luteum dysfunction and concomitant low progesterone were the primary causes of the decreased fertility. In contrast to the faint expression observed in most of the adult tissues, Neat1 was highly expressed in the corpus luteum, and the formation of luteal tissue was severely impaired in nearly half of the Neat1 KO mice. These observations suggest that Neat1 is essential for the formation of the corpus luteum and for the subsequent establishment of pregnancy under a suboptimal condition that has not yet been identified.

It was shown that full-mouth SRP using systemically administered azithromycin was a clinically and bacteriologically useful basic periodontal treatment for severe chronic periodontitis.

The application of erbium:yag laser (Er:YAG) irradiation has been investigated for periodontal therapy. The purpose of this study was to evaluate the effects of Er: YAG laser irradiation on root surfaces using a scanning electron microscope (SEM) and to determine the laser's ability to remove lipopolysaccharides (LPS). Infrared spectrophotometry was used to investigate the effects of the laser on LPS applied to root dentin pellets. Premolare extracted for orthodontic reasons were prepared for this study. The crowns were resected below the cemento-enamel junction, longitudinally sectioned, and the contents of the pulp chamber were removed. Then 15 root tips (5X5X1 mm) were classified into 3 groups of 5 each as follows: group 1, tips without any treatment; group 2, planed tips with the cement layers left untouched; and group 3, planed until the dentin surface was disclosed. The center of each specimen was used as the experimental irradiated area and the peripheral area served as a control. The quantity of vapor delivered by Er: YAG laser was highly increased, and the irradiated areas displayed little morphogenetic changes. The lyophilized sample LPS 0111 B4 from E. coli was then mixed with potassium bromide and pressed into a tablet, which was examined at 4,000-650 Kayser. The lyophilized LPS had a peak at 2.94 µ . LPS on the root dentin pellets was cleared away as much as possible by 150 washings in pyrogen-free water using an ultrasonic cleaner. Five µ of 24 EU LPS solution was dropped on the root dentin pellets, which were then irradiated by the Er: YAG laser, and washed using the ultrasonic cleaner in pyrogen-free water. The amount of the extracted LPS solution was determined by spectrophotometer at 405nm. The Er: YAG laser could remove 83.1% of the LPS. This study suggests that Er:YAG laser irradiation might be useful for root conditioning in periodontal therapy. However, clinical testing is necessary to establish what, if any, utility the Er:YAG laser has as a part of periodontal therapy.

Mmp-20 and Klk4 are the two enamel proteases. Can both enzymes process amelogenin to generate the major cleavage products that accumulate during the secretory stage of amelogenesis? We isolated Mmp-20 and Klk4 from developing pig teeth and used them to digest the tyrosine-rich amelogenin polypeptide (TRAP), the leucine rich-amelogenin protein (LRAP), and five fluorescence peptides. We characterized the digestion products by LC-MSMS, SDS-PAGE, and C18 RP-HPLC monitored with fluorescence and UV detectors. Mmp-20 cleaves amelogenin sequences after Pro162, Ser148, His62, Ala63, and Trp45. These cleavages generate all of the major cleavage products that accumulate in porcine secretory stage enamel: the 23-kDa, 20-kDa, 13-kDa, 11-kDa, and 6-kDa (TRAP) amelogenins. Mmp-20 cleaves LRAP after Pro45 and Pro40, producing the two LRAP products previously identified in tooth extracts. Among these key cleavage sites, Klk4 was only able to cleave after His62. We propose that Mmp-20 alone processes amelogenin during the secretory stage.