Ethylene regulates miRNA-mediated lignin biosynthesis and leaf serration in Arabidopsis thaliana.

microRNAs (miRNAs) regulate target gene expression by pairing to target mRNAs, leading to mRNA degradation or translation inhibition. Out of several miRNAs in Arabidopsis, miR397b and miR857 regulate secondary growth by modulating lignin polymerization and deposition in secondary xylem cells by targeting laccases. Interestingly, the phytohormone ethylene is also suggested to have a role in lignin biosynthesis in tension wood formation. Despite this information, it is not known whether ethylene has any role in controlling secondary growth via miRNAs-mediated pathways. In this study, we elucidate that ethylene acts upstream to the miR397b/miR857-laccases module and negatively regulates lignin biosynthesis by directly activating the expression of both the miRNAs. The binding of EIN3 to the promoter of miR397b is further validated by yeast one-hybrid assay. In addition to its role in lignification, ethylene also regulates leaf serration by directly regulating the expression of NAC transcription factors, like CUP-SHAPED COTYLEDON2 (CUC2) and CUC3. Together, our study suggests a novel mechanism involving ethylene and miRNAs in lignin biosynthesis and leaf serration in Arabidopsis thaliana.

Clinical and Radiographic Analysis of Novabone Putty with Platelet-Rich Fibrin in the Treatment of Periodontal Intrabony Defects: A Randomized Control Trial.

BACKGROUND: Periodontal regeneration remains one of the crucial issues in the field of periodontology. Periodontal intrabony defects could be treated by surgical intervention through various alloplastic bone graft substitutes. The Food and Drug Administration approved, Novabone putty is one of the recently marketed bone graft substitutes, which has been used in the present study. This study also incorporates the placement of platelet-rich fibrin (PRF) in combination with Novabone putty. MATERIALS AND METHODS: Twenty patients were included in the study and were allocated to either Group A or Group B through randomization. Group A included the placement of Novabone putty in the periodontal intrabony defects, whereas Group B included the placement of Novabone putty along with PRF. Statistical analysis of plaque index, gingival index, probing pocket depth, relative attachment level, and intraoral periapical radiographs was performed. RESULTS: Statistical more significant difference (P < 0.05) in probing pocket depth, and relative attachment level was observed in Group B (Novabone putty and PRF) in comparison to Group A (Novabone putty). CONCLUSION: Evaluation of efficacy of Novabone putty along with PRF produced more favorable results in relative attachment level gain and more reduction in probing pocket depth when compared to Novabone putty alone.

Light-regulated expression of terpene synthase gene, AtTPS03, is controlled by the bZIP transcription factor, HY5, in Arabidopsis thaliana.

The terpenoid pathway serves as an essential source of all isoprenoid precursors and metabolites that are of great pharmacological importance. The major enzymes for the synthesis of these diverse molecules is the terpene synthases (TPSs), which catalyse the final step of the synthesis of the important secondary products, the terpenes. Previous studies have reported that the various environmental factors, including light govern the synthesis of terpenoids. However, the molecular components and steps involved in the regulation of synthesis of these molecules have not been studied in detail. In this study, we report that the light regulates the expression of the members of terpene synthase gene family in Arabidopsis thaliana. We demonstrate that ELONGATED HYPOCOTYL (HY5), a basic leucine zipper transcription factor, plays a crucial role in light-mediated transcriptional regulation of terpene synthase, AtTPS03. Expression analysis using hy5-215 mutant and HY5 over-expression lines revealed that HY5 acts as a positive regulator of AtTPS03. Additionally, studies including AtTPS03 Promoter::reporter transgenic lines in wild-type and hy5-215, as well as electrophoretic mobility shift assay (EMSA), suggest an interaction of HY5 with the AtTPS03 promoter. Together, our analysis indicate the requirement for HY5 for light-mediated regulation of AtTPS03 for the terpenoid biosynthesis in Arabidopsis.

Role of 0.5 M mannitol as an adjuvant with lidocaine with or without epinephrine for inferior alveolar nerve block: A randomized control trial.

BACKGROUND: The most commonly used local anesthetic in dentistry is lidocaine. For decades, mannitol is the most widely used agent in the management of raised intracranial pressure and as prophylaxis against acute renal failure surgeries. MATERIAL AND METHODS: 120 patients were randomly divided into four groups, 30 patients in each group. Group A was administered 2% lidocaine with 1:80000 epinephrine; group B, 2% lidocaine with 1:80000 epinephrine and 0.5 M mannitol; group C, 2% lidocaine and 0.5 M mannitol; and group D (control group), 2% lidocaine for achieving local anesthesia. Extraction of lower erupted tooth was done under inferior alveolar nerve block. Parameters taken were onset of anesthesia, duration of anesthesia and pain. Heft-Parker visual analogue scale was taken to evaluate the pain response during procedure after every 10 minutes until complete return of sensation by probing. The Chi-square test was used to compare the pain among the groups. The continuous variables were compared among the groups by one way analysis of variance (ANOVA) followed by Tukey's post-hoc comparison tests. The p-value <0.05 was considered significant. RESULTS: The onset of tingling sensation was higher among the patients of group C (1.53±0.57) than group B (1.50±0.58), group D (1.48±0.51) and group A (1.45±0.62) but difference among the groups was statistically insignificant (p >0.05). The total time in return of sensation was higher among the patients of group C (70.30±4.34) than group A (65.94±3.45), group B (62.23±7.47) and group D (47.70±8.04) but difference among the groups was found to be statistically significant (p=0.0001). There was no significant (p >0.05) difference in the pain at baseline and at start. No pain was found among all the patients from 10 minutes to subsequent time intervals. CONCLUSIONS: Mannitol was effective in increasing the efficacy of lidocaine as an adjuvant to local anesthetic solution in inferior alveolar nerve block. Key words:Inferior alveolar nerve block, lidocaine, local anesthesia, mannitol.