Apical Development Research Articles

Transcriptional landscape of sweetpotato root tip development at the single-cell level

Single-cell transcriptome sequencing (scRNA-seq) is a powerful tool for describing the transcriptome dynamics of plant development but has not yet been utilized to analyze the tissue ontology of sweetpotato. This study established a stable method for isolating single protoplast cells for scRNA-seq to reveal the cell heterogeneity of sweetpotato root tip meristems at the single-cell level. The study analyzed 12,172 single cells and 27,355 genes in the root tips of the sweetpotato variety Guangshu 87, which were distributed into 15 cell clusters. Pseudo-time analysis showed that there were transitional cells in the apical development trajectory of mature cell types from stem cell niches. Furthermore, we identified novel development regulators of sweetpotato tubers via trajectory analysis. The transcription factor IbGATA4 was highly expressed in the adventitious roots during the development of sweetpotato root tips, where it may regulate the development of sweetpotato root tips. In addition, significant differences were observed in the transcriptional profiles of cell types between sweetpotato, Arabidopsis thaliana, and maize. This study mapped the single-cell transcriptome of sweetpotato root tips, laying a foundation for studying the types, functions, differentiation, and development of sweetpotato root tip cells.

Interpretation by literature review of the use of calcium hydroxide as an intra-ductal medication

The effectiveness of calcium hydroxide as an antiseptic agent in endodontics has recently gained relevance, being crucial to ensure optimal results in endodontic treatments. The aim of the study was to interpret the use of calcium hydroxide as an intra-endodontic medication by means of a literature review. A narrative review of the updated literature was performed, with the aim of describing the effects of CaOH and exposing the different clinical procedures in which it is used, as well as the results of its application in endodontic therapy. Clinical trials, meta-analyses and original and published articles from 2018 to 2023, in English or Spanish, were included. It was found that calcium hydroxide plays a key role in endodontics due to its dissociation into calcium and hydroxyl ions, which contributes to its antimicrobial and biological efficacy. Its clinical application is extensive, including preventive endodontics, direct and indirect pulp capping, pulp curettage and pulpotomies, especially in teeth with incomplete apical development. The mechanism behind its antimicrobial action lies in the diffusion of calcium ions and the increase in pH, which limit the rate and enhance the antimicrobial effect in root canals. It was concluded that, for an effective endodontic treatment, it is necessary to eliminate all microorganisms from the root canal. In addition, the microorganism such as E. faecalis has a high resistance to endodontic treatment, which is due to its ability to penetrate into the dentinal tubules, tolerate high alkalinity, and form biofilms

Early ground rolling is highly effective in delaying spikelet initiation in early-sown spring wheat

ABSTRACT Ground rolling delays spikelet initiation and thus would be expected to reduce frost injury in early-sown spring wheat. To characterize the relationship between the timing of rolling and the delay of spikelet initiation, we investigated apical development of early-sown spring wheat plants (Triticum aestivum L. cv. ‘Ayahikari’) rolled at the 1-, 2-, 3-, or 4-leaf stage in three years. All rollings delayed apical development. The delay was largest in plants treated at the 1- or 2-leaf stage: spikelet initiation by 5.0 days, the start of internode elongation by 5.5 days, and jointing by 3.5 days relative to the control. Our results and recent meteorological data suggest that in early cropping of spring wheat in the Tokai region of Japan, the earliest sowing date to avoid frost injury can be advanced by 3 days by rolling.

Treatment Outcome of Regenerative Endodontic Procedures for Necrotic Immature and Mature Permanent Teeth: A Systematic Review and Meta-Analysis Based on Randomised Controlled Trials.

To analyse whether the stage of apical development affects the effectiveness of regenerative endodontic treatment by comparing the outcomes for necrotic mature and immature permanent teeth treated with regenerative endodontic procedures. Multiple databases (PubMed, Cochrane Library, Web of Science, EMBASE and OpenGrey databases) were searched through February 17th, 2022. Inclusion criteria were randomised controlled trials that included treatment of necrotic immature or mature permanent teeth using any regenerative endodontic procedures (REPs) that aimed to achieve pulp revascularisation or regeneration. The Cochrane Risk of Bias 2.0 tool was used to assess risk of bias. The included indicators were asymptomatic sign, success, pulp sensitivity, and discolouration. The extracted data were expressed by percentage for statistical analysis. The random effect model was used to explain the results. Comprehensive Meta-Analysis Version 2 was used to perform the statistical analyses. Twenty-seven RCTs were eligible for inclusion in the meta-analysis. The success rates of necrotic immature and mature permanent teeth were 95.6% (95% CI, 92.4%-97.5%; I2=34.9%) and 95.5% (95%CI, 87.9%-98.4%; I2=0%), respectively. The asymptomatic rates of necrotic immature and mature permanent teeth were 96.2% (95%CI, 93.5%-97.9%; I2=30.1%) and 97.0% (95%CI, 92.6%-98.8%; I2=0%), respectively. The treatment of immature and mature necrotic permanent teeth with REPs yields high success rates and low symptomatic rates. The incidence of positive sensitivity response for electric pulp testing in necrotic immature permanent teeth (25.2% [95% CI, 18.2%-33.8%; I2=0%]) was lower than that in necrotic mature permanent teeth (45.4% [95% CI, 27.2%-64.8%; I2=75.2%]), and this difference was statistically significant. The restoration of pulp sensitivity seems to be more evident in necrotic mature permanent teeth than in necrotic immature permanent teeth. The crown discolouration rate of immature permanent teeth was 62.5% (95% CI, 49.7%-73.8%; I2=76.1%). Necrotic immature permanent teeth have a considerable crown discolouration rate. REPs for both immature and mature necrotic permanent teeth yield high success rates and promote root development. The vitality responses seem to be more evident in necrotic mature permanent teeth than in necrotic immature permanent teeth.

Brassinosteroids promote etiolated apical structures in darkness by amplifying the ethylene response via the EBF-EIN3/PIF3 circuit.

Germinated plants grow in darkness until they emerge above the soil. To help the seedling penetrate the soil, most dicot seedlings develop an etiolated apical structure consisting of an apical hook and folded, unexpanded cotyledons atop a rapidly elongating hypocotyl. Brassinosteroids (BRs) are necessary for etiolated apical development, but their precise role and mechanisms remain unclear. Arabidopsis thaliana SMALL AUXIN UP RNA17 (SAUR17) is an apical-organ-specific regulator that promotes production of an apical hook and closed cotyledons. In darkness, ethylene and BRs stimulate SAUR17 expression by transcription factor complexes containing PHYTOCHROME-INTERACTING FACTORs (PIFs), ETHYLENE INSENSITIVE 3 (EIN3), and its homolog EIN3-LIKE 1 (EIL1), and BRASSINAZOLE RESISTANT1 (BZR1). BZR1 requires EIN3 and PIFs for enhanced DNA-binding and transcriptional activation of the SAUR17 promoter; while EIN3, PIF3, and PIF4 stability depends on BR signaling. BZR1 transcriptionally downregulates EIN3-BINDING F-BOX 1 and 2 (EBF1 and EBF2), which encode ubiquitin ligases mediating EIN3 and PIF3 protein degradation. By modulating the EBF-EIN3/PIF protein-stability circuit, BRs induce EIN3 and PIF3 accumulation, which underlies BR-responsive expression of SAUR17 and HOOKLESS1 and ultimately apical hook development. We suggest that in the etiolated development of apical structures, BRs primarily modulate plant sensitivity to darkness and ethylene.

One Step Apexification in a Resorbed Tooth Using Autologous PRF as Internal Matrix and Biodentine Apical Plug

Apexification is defined as a method to induce a calcific barrier in a root with open apex or the continued apical development of an incompletely formed root in teeth with necrotic pulp tissue. The presented case was of a 26‑year‑old male patient with discoloured tooth associated with external resorption and periapical pathology in relation to the upper front right tooth. Teeth with open apex due to root end resorption pose difficulties during endodontic treatment because of the wide‑open root apex and thin dentin walls. This article describes the procedure of single‑visit apexification using a new calcium silicate‑based material (Biodentine) as an apical barrier along with platelet‑rich fibrin as internal matrix.

Overexpression of HANABA TARANU in cultivated strawberry delays flowering and leads to defective flower and fruit development

Cultivated strawberry is one of the most important horticultural crops in the world, and the fruit yields and economic benefits are largely dependent on the quality of floral initiation and floral organ development. However, the underlying regulatory mechanisms controlling these processes in strawberry are largely unknown. In this study, the function of a GATA transcription factor gene, HANABA TARANU (HAN), in floral initiation and floral organ development was characterized in strawberry. FaHAN is expressed in four whorls of the floral organs. Overexpression (OE) of FaHAN in the strawberry cultivar ‘Benihoppe’ delayed flowering by at least one week by affecting key genes, such as TERMINAL FLOWER 1, APETALA 1…and increased the number of runners. FaHAN-OE plants also showed malformed floral organs, especially the deformed stigmas with disordered arrangement. Several key genes for pistil apical development such as STYLISH, YUCCA 1, and auxin-related genes such as GH3.5, PIN-FORMED 1, which play important roles in pistil primordium development in many plant species, were all down-regulated in FaHAN-OE plants. Further observations showed that the fruit deformity rate was nearly 4-fold higher than in control plants. Together, this study provides a new approach for exploring floral initiation and floral organ development in strawberry.

Radiographic study of the rhizogenesis in Brazilian adolescents and its contribution to dental age estimation

When applied to the examination of the living, methods for dental age estimation are based on clinical (visual or direct) or radiographic (radiographic or indirect) analyses. Two-dimensional (2D) techniques, such as panoramic radiography, or three-dimensional (3D) imaging modalities, such as cone-beam computed tomography, enable the visualization of multiple anatomical structures simultaneously. The development of each structure contributes to the age estimation process by providing age information. This study tested the performance of age information from rhizogenesis for age estimation. The sample consisted of panoramic radiographs of 568 female (n = 284) and male (n = 284) individuals, aged between 12 and 17.99 years. Tooth development was classified according to Demirjian et al. (1973) technique, and the age was calculated with the method of Willems et al. (2001). The average chronological age of each individual was compared with the estimated dental age, allowing the quantification of the error of the method for each age group at intervals of one year each. For both sexes, there was an overestimation of the chronological age in the age group of 12 |— 14.99 years, while age was underestimated in the age group of 16 |— 17.99 years (p < 0.0001). Statistically significant differences between sexes were observed in the age group of 15 |— 17.99 years (p < 0.05). The increasing error of the method in the late stages of root formation suggests that age information from the scarce remaining apical development of the permanent dentition may not be appropriate enough for sufficiently accurate forensic examinations.

Apexification of an infected untreated immature tooth with calplus (Calcium hydroxide paste with Iodoform)

Apexification is a method to induce a calcific barrier across an open apex or the sustained apical development of an incomplete root in teeth with necrotic pulp. Apical closure occurs approximately three years after eruption. Apexification is a treatment option that is done with the aim of apical repair by formation of hard tissue barrier through apex. Conventionally, a calcified barrier is inducted using a calcium hydroxide mixture. Various materials that can be used for apexification include Calcium hydroxide, MTA, Tricalcium phosphate, Dentin chips, Calcium phosphate ceramics and hydroxyapatite and bone morphogenetic proteins. Calcium hydroxide is the most common and traditional material employed for inducing apexification. Multi visit technique requiring 6-24 months to complete by using calcium hydroxide paste with Iodoform.

The cell cycle arrested results in the premature advent of apical leaflets development cessation in Zygophyllum xanthoxylon

The cell cycle arrested results in the premature advent of apical leaflets development cessation in Zygophyllum xanthoxylon

Effects of chemical topping on cotton development, yield and quality in the Yellow River Valley of China

Topping is a cultivation method that is widely practiced due to the indeterminate growth character of cotton (Gossypium hirsutum L.). Among the different methods of accomplishing topping, manual topping is common in the Yellow River Valley of China, although it is time- and labor-intensive. The objective of this study was to characterize the responses of cotton to different topping treatments with respect to development, yield and quality. This study included field experiments from 2015 to 2016 with three different topping methods: manual topping (MT), chemical topping (CT) using mepiquat chloride, and a non-decapitation treatment (NT). We found that the plant height, the number of fruiting branches and the length of upper fruiting branches of cotton treated with CT were significantly lower than NT. The chlorophyll content of cotton treated with CT was not significantly different from NT, but was higher than that of MT in the later season. CT enhanced plant development with reduced endogenous gibberellic acid and abscisic acid contents, and the apical development of the main stem was inhibited. Compared with MT, CT significantly increased the biomass of the vegetative parts. Most importantly, there were no significant differences in the yield or fiber quality between MT and CT. These findings suggested that CT, a simplified and effective topping method, could be utilized as an alternative in the Yellow River Valley of China.

HYPONASTIC LEAVES 1 is required for proper establishment of auxin gradient in apical hooks.

During seedling germination under the soil surface, HYPONASTIC LEAVES 1 regulates apical hook development by modulating the formation of an auxin gradient.

Identification and characterization of miRNAs associated with sterile flower buds in the tea plant based on small RNA sequencing

BackgroundmiRNAs are a type of conserved, small RNA molecule that regulate gene expression and play an important role in the growth and development of plants. miRNAs are involved in seed germination, root development, shoot apical meristem maintenance, leaf development, and flower development by regulating various target genes. However, the role of miRNAs in the mechanism of tea plant flower sterility remains unclear. Therefore, we performed miRNA sequencing on the flowers of fertile male parents, female parents, and sterile offspring.ResultsA total of 55 known miRNAs and 90 unknown miRNAs were identified. In the infertile progeny, 37 miRNAs were differentially expressed; 18 were up-regulated and 19 were down-regulated. miR156, miR157, miR164, miR167, miR169, miR2111 and miR396 family members were down-regulated, and miR160, miR172 and miR319 family members were up-regulated. Moreover, we predicted that the 37 differentially expressed miRNAs target a total of 363 genes, which were enriched in 31 biological functions. We predicted that miR156 targets 142 genes, including ATD1A, SPL, ACA1, ACA2, CKB22 and MADS2.ConclusionWe detected a large number of differentially expressed miRNAs in the sterile tea plant flowers, and their target genes were involved in complex biological processes. Among these miRNAs, the down-regulation of miR156 may be one of the factor in the formation of sterile floral buds in tea plants.

Microrna Regulation of Nodule Zone-Specific Gene Expression In Soybean

Microrna Regulation of Nodule Zone-Specific Gene Expression In Soybean

Biodentine: Material of choice for apexification

Pulp necrosis with incomplete root formation in permanent teeth leads to open apex of the particular tooth which leads to the formation of the periapical pathology. The management of such cases poses a great endodontic challenge. Apexification is the process of induction of calcific barrier across the open apex or the continued apical development in an immature tooth with infected necrotic pulp. The aim of this case report is to share a successful apexification of maxillary central incisors with by using Biodentine without complications.Biodentine is a material of choice for single visit apexification.

Wood development regulators involved in apical growth in Pinus canariensis.

The shoot apical meristem is responsible of seasonal length increase in plants. In woody plants transition from primary to secondary growth is also produced during seasonal apical growth. These processes are controlled by different families of transcription factors. Levels of transcriptomic activity during apical growth were measured by means of a cDNA microarray designed from sequences related to meristematic activity in Pinus canariensis. The identification of differentially expressed genes was performed using a time-course analysis. A total of 7170 genes were differentially expressed and grouped in six clusters according to their expression profiles. We identified master regulators, such as WUSCHEL-like HOMEOBOX (WOX), to be involved in the first stages of apical development, i.e. growth of primary tissues, while other transcription factors, such as Class III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) and KNOTTED-like (KNOX) and BEL1-like (BELL) HOMEODOMAIN proteins, were found to be induced during last stages of apical seasonal development, already with secondary growth. Our results reveal the main expression patterns of these genes during apical development and the transition from primary to secondary stem growth. In particular, the regulatory factors identified play key roles in controlling stem architecture and constitute candidate genes for the study of other development processes in conifers.

Maturogenesis by Pulp Revascularization in an Immature Necrotic Permanent Tooth in a Pediatric Patient: A 15 Month Follow-up Case Report

Endodontic treatment of immature necrotic permanent teeth is clinically challenging and poses a risk of inducing dentin wall fracture or extending gutta-percha into the periapical tissue during root canal filling. Pulp revascularization is a promising alternative for the treatment of such immature necrotic permanent teeth offering great potential to avoid the need for traditional apexification with calcium hydroxide or the need to achieve an artificial apical barrier with mineral trioxide aggregate. Pulp revascularization allows the stimulation of the apical development and the root maturation of immature teeth by physiologically strengthening the canal walls. The present case report describes the case of successful revascularization of the necrotic infected pulp space of an immature permanent maxillary central incisor induced in vivo by stimulation of a blood clot from the periapical tissues into the canal space. Thickening of the canal wall and complete apical closure were confirmed 15 months after the treatment.

SAUR17 and SAUR50 Differentially Regulate PP2C-D1 during Apical Hook Development and Cotyledon Opening in Arabidopsis.

Following germination in the dark, Arabidopsis (Arabidopsis thaliana) seedlings undergo etiolation and develop apical hooks, closed cotyledons, and rapidly elongating hypocotyls. Upon light perception, the seedlings de-etiolate, which includes the opening of apical hooks and cotyledons. Here, we identify Arabidopsis Small Auxin Up RNA17 (SAUR17) as a downstream effector of etiolation, which serves to bring about apical hook formation and closed cotyledons. SAUR17 is highly expressed in apical hooks and cotyledons and is repressed by light. The apical organs also express a group of light-inducing SAURs, as represented by SAUR50, which promote hook and cotyledon opening. The development of etiolated or de-etiolated apical structures requires asymmetric differential cell growth. We present evidence that the opposing actions of SAUR17 and SAUR50 on apical development largely result from their antagonistic regulation of Protein Phosphatase 2C D-clade 1 (PP2C-D1), a phosphatase that suppresses cell expansion and promotes apical hook development in the dark. SAUR50 inhibits PP2C-D1, whereas SAUR17 has a higher affinity for PP2C-D1 without inhibiting its activity. PP2C-D1 predominantly associates with SAUR17 in etiolated seedlings, which shields it from inhibitory SAURs such as SAUR50. Light signals turn off SAUR17 and upregulate a subgroup of SAURs including SAUR50 at the inner side of the hook and cotyledon cells, leading to cell expansion and unfolding of the hook and cotyledons.

The effects of continuously high temperatures on apical development and yield of four varieties of wheat

The aim of the experiment was to examine how wheat responded to an extended period of high temperatures under controlled conditions to supplement field studies with these varieties on Lombok Island. Two Indonesian wheat varieties (Nias and Dewata) and two Australian varieties (Axe and Gladius) were examined in growth room experiments at 3 different temperature regimes 32/23°C, 28/20°C and 25/15°C day/night with 12 h daylight. Temperature and photoperiod were selected to simulate conditions on Lombok Island, at lowland (32/23°C) and highland (28/20°C) sites. A third temperature (25/15°C) was selected to represent the temperature in a more temperate wheat producing area. The rate of plant development increases with the rise of the temperatures up to an optimum temperature and slower after further increases. Despite being exposed to high temperatures from the establishment, the effect of high temperature was more severe during the reproductive stage as seen by the fact that yield was more affected than dry matter accumulation and yield was most strongly related to grain number. Genetic variability in response to heat stress was evident with the Indonesian varieties being more tolerant to high temperatures than Australian varieties. Nias and Dewataproduced higher yield and biomass.

Cell lineage-specific transcriptome analysis for interpreting cell fate specification of proembryos

In Arabidopsis, a zygote undergoes asymmetrical cell division that establishes the first two distinct cell types of early proembryos, apical and basal cells. However, the genome-wide transcriptional activities that guide divergence of apical and basal cell development remain unknown. Here, we present a comprehensive transcriptome analysis of apical and basal cell lineages, uncovering distinct molecular pathways during cell lineage specification. Selective deletion of inherited transcripts and specific de novo transcription contribute to the establishment of cell lineage-specific pathways for cell fate specification. Embryo-related pathways have been specifically activated in apical cell lineage since 1-cell embryo stage, but quick transcriptome remodeling toward suspensor-specific pathways are found in basal cell lineage. Furthermore, long noncoding RNAs and alternative splicing isoforms may be involved in cell lineage specification. This work also provides a valuable lineage-specific transcriptome resource to elucidate the molecular pathways for divergence of apical and basal cell lineages at genome-wide scale.