Nanoleakage of apical sealing using a calcium silicate-based sealer according to canal drying methods.

Objectives: This study investigated the nanoleakage of root canal obturations using calcium silicate-based sealer according to different drying methods. Materials and Methods: Fifty-two extracted mandibular premolars with a single root canal and straight root were selected for this study. After canal preparation with a nickel-titanium rotary file system, the specimens were randomly divided into 4 groups according to canal drying methods (1: complete drying, 2: blot drying/distilled water, 3: blot drying/NaOCl, 4: aspiration only). The root canals were obturated using a single-cone filling technique with a calcium silicate-based sealer. Nanoleakage was evaluated using a nanoflow device after 24 hours, 1 week, and 1 month. Data were collected twice per second at the nanoscale and measured in nanoliters per second. Data were statistically analyzed using the Kruskal-Wallis and Mann-Whitney U-tests (p < 0.05). Results: The mean flow rate measured after 24 hours showed the highest value among the time periods in all groups. However, the difference in the flow rate between 1 week and 1 month was not significant. The mean flow rate of the complete drying group was the highest at all time points. After 1 month, the mean flow rate in the blot drying group and the aspiration group was not significantly different. Conclusions: Within the limitations of this study, the canal drying method had a significant effect on leakage and sealing ability in root canal obturations using a calcium silicate-based sealer. Thus, a proper drying procedure is critical in endodontic treatment.

A Study on Nanoleakage of Apical Retrograde Filling of Premixed Calcium Silicate-Based Cement Using a Lid Technique.

This study aimed to compare the nanoleakage of retrograde fillings with premixed calcium silicate-based putty and mineral trioxide aggregate (MTA), using two different techniques (traditional and Lid). Sixty-four extracted human teeth were decoronated, then root canals and ends were instrumented for retrograde filling and divided into four groups according to the retrograde filling technique: the traditional and the Lid technique. Each group (n = 15) was filled with Ceraseal + Well-Root putty, Well-Root putty, Ceraseal + ProRoot MTA, and ProRoot MTA. The nanoleakage was evaluated using the Nanoflow device (IB Systems) on days 1, 3, 7, 15 and 30. Data were collected twice per second at the nanoscale (nL/s) and calculated after archiving the stabilization of fluid flow. The Kruskal-Wallis and Mann-Whitney U-tests were used for statistical analysis. All groups showed enhanced sealing ability over time. Regardless of filling materials, the Well-Root putty, Ceraseal+Well-Root putty, and Ceraseal+ProRoot MTA groups indicated less nanoleakage than the ProRoot MTA group in the first week of evaluation (p < 0.05). Although all groups did not show significant differences after 2 weeks, the Ceraseal+ProRoot MTA group leaked less than ProRoot MTA on Days 3 and 7 (p < 0.05). The scanning electron microscopic examined good adaptation to the cavity wall, which was similar to nanoleakage results. Premixed calcium silicate-based putty retrograde filling material alone and using the "lid technique" were shown to be faster and less prone to nanoleakage when compared to MTA.

Revised evaluation objectives of the Korean Dentist Clinical Skill Test: a survey study and focus group interviews

PURPOSE: This study aimed to propose a revision of the evaluation objectives of the Korean Dentist Clinical Skill Test by analyzing the opinions of those involved in the examination after a review of those objectives. METHODS: The clinical skill test objectives were reviewed based on the national-level dental practitioner competencies, dental school educational competencies, and the third dental practitioner job analysis. Current and former examinees were surveyed about their perceptions of the evaluation objectives. The validity of 22 evaluation objectives and overlapping perceptions based on area of specialty were surveyed on a 5-point Likert scale by professors who participated in the clinical skill test and dental school faculty members. Additionally, focus group interviews were conducted with experts on the examination. RESULTS: It was necessary to consider including competency assessments for "emergency rescue skills" and "planning and performing prosthetic treatment." There were no significant differences between current and former examinees in their perceptions of the clinical skill test's objectives. The professors who participated in the examination and dental school faculty members recognized that most of the objectives were valid. However, some responses stated that "oromaxillofacial cranial nerve examination," "temporomandibular disorder palpation test," and "space management for primary and mixed dentition" were unfeasible evaluation objectives and overlapped with dental specialty areas. CONCLUSION: When revising the Korean Dentist Clinical Skill Test's objectives, it is advisable to consider incorporating competency assessments related to "emergency rescue skills" and "planning and performing prosthetic treatment."

The obesity paradox in younger adult patients with sepsis: analysis of the MIMIC-IV database.

BACKGROUND: The obesity paradox suggests that individuals with obesity may have a survival advantage against specific critical illnesses, including sepsis. However, whether this paradox occurs at younger ages remains unclear. Therefore, we aimed to investigate whether obesity could improve survival in younger adult patients with sepsis. METHODS: We used clinical data sourced from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients with Sequential Organ Failure Assessment score ≥2 and suspected infection at the time of ICU admission were identified as having sepsis, following the Sepsis-3 definition. Individuals were classified into the obesity (BMI ≥30 kg/m²) and non-obesity (BMI <30 kg/m²) groups. Patients aged <50 and ≥50 years were categorized as younger adult patients and older patients, respectively. RESULTS: Of 73,181 patients in the MIMIC-IV ICU database, 18,120 satisfied the inclusion criteria: 2642 aged <50 years and 15,478 aged ≥50 years. The Kaplan-Meier curve showed that obesity was not associated with an improved mortality rate among younger adult patients with sepsis (log-rank test: P = 0.197), while obesity exhibited a survival benefit in older patients with sepsis (log-rank test: P < 0.001). After propensity score matching, in-hospital mortality did not differ significantly between the obesity and non-obesity groups (13.3% vs. 12.2%; P = 0.457) in the younger adult patients with sepsis. Multivariate logistic regression analysis revealed that BMI was not an independent risk factor for in-hospital mortality in younger adult patients with sepsis (underweight: adjusted odds ratio [aOR] 1.72, P = 0.076; overweight: aOR 0.88, P = 0.437; obesity: aOR 0.93, P = 0.677; and severe obesity: aOR 1.22, P = 0.580, with normal weight as the reference). CONCLUSION: Contrary to findings regarding older patients with sepsis, our findings suggest that the obesity paradox does not apply to younger adult patients with sepsis.

PGRMC1 Ablation Protects from Energy-Starved Heart Failure by Promoting Fatty Acid/Pyruvate Oxidation.

Heart failure (HF) is an emerging epidemic with a high mortality rate. Apart from conventional treatment methods, such as surgery or use of vasodilation drugs, metabolic therapy has been suggested as a new therapeutic strategy. The heart relies on fatty acid oxidation and glucose (pyruvate) oxidation for ATP-mediated contractility; the former meets most of the energy requirement, but the latter is more efficient. Inhibition of fatty acid oxidation leads to the induction of pyruvate oxidation and provides cardioprotection to failing energy-starved hearts. One of the non-canonical types of sex hormone receptors, progesterone receptor membrane component 1 (Pgrmc1), is a non-genomic progesterone receptor associated with reproduction and fertility. Recent studies revealed that Pgrmc1 regulates glucose and fatty acid synthesis. Notably, Pgrmc1 has also been associated with diabetic cardiomyopathy, as it reduces lipid-mediated toxicity and delays cardiac injury. However, the mechanism by which Pgrmc1 influences the energy-starved failing heart remains unknown. In this study, we found that loss of Pgrmc1 inhibited glycolysis and increased fatty acid/pyruvate oxidation, which is directly associated with ATP production, in starved hearts. Loss of Pgrmc1 during starvation activated the phosphorylation of AMP-activated protein kinase, which induced cardiac ATP production. Pgrmc1 loss increased the cellular respiration of cardiomyocytes under low-glucose conditions. In isoproterenol-induced cardiac injury, Pgrmc1 knockout resulted in less fibrosis and low heart failure marker expression. In summary, our results revealed that Pgrmc1 ablation in energy-deficit conditions increases fatty acid/pyruvate oxidation to protect against cardiac damage via energy starvation. Moreover, Pgrmc1 may be a regulator of cardiac metabolism that switches the dominance of glucose-fatty acid usage according to nutritional status and nutrient availability in the heart.

Immunotherapeutic effects of recombinant colorectal cancer antigen produced in tomato fruits.

The production of pharmacological vaccines in plants has been an important goal in the field of plant biotechnology. GA733-2, the protein that is also known as colorectal carcinoma (CRC)-associated antigen, is a strong candidate to produce a colorectal cancer vaccine. Tomato is the one of the major targets for production of an edible vaccine, as tomato is a fruit consumed in fresh form. It also contains high content of vitamins that aid activation of immune response. In order to develop an edible colorectal cancer vaccine, the transgene rGA733-Fc that encodes a fusion protein of GA733-2, the fragment crystallizable (Fc) domain, and the ER retention motif (rGA733-Fc) was introduced into tomato plants (Solanum lycopersicum cv. Micro-Tom). The transgenic plants producing rGA733-Fc (rGA733-FcOX) protein were screened based on stable integration of transgene expression cassette and expression level of rGA733-Fc protein. Further glycosylation pattern analysis revealed that plant derived rGA733-Fc protein contains an oligomannose glycan structure, which is a typical glycosylation pattern found on ER-processing proteins. The red fruits of rGA733-FcOX transgenic tomato plants containing approximately 270 ng/g FW of rGA733-Fc protein were orally administered to C57BL/6 mice. Oral administration of tomato fruits of the rGA733-Fc expressing transgenic plants delayed colorectal cancer growth and stimulated immune responses compared to oral administration of tomato fruits of the h-Fc expressing transgenic plants in the C57BL/6J mice. This is the first study showing the possibility of producing an edible colorectal cancer vaccine using tomato plants. This research would be helpful for development of plant-derived cancer edible vaccines.

Identification of essential element determining fruit-specific transcriptional activity in the tomato HISTIDINE DECARBOXYLASE A gene promoter.

KEY MESSAGE: In SlHDC-A promoter, SlHDC-A core-ES is an essential region for fruit-specific expression and interacts with GATA, HSF and AP1. Triplication of essential region was proposed as a minimal fruit-specific promoter. In plant biotechnology, fruit-specific promoter is an important tool for the improvement and utilization of tomato fruit. To expand our understanding on fruit-specific expression, it is necessary to determine the promoter region involved in fruit-specific transcriptional activity and transcriptional regulations of the promoter. In previous study, we isolated a fruit-specific SlHDC-A core promoter specifically expressed during tomato ripening stages. In this study, we identified SlHDC-A promoter region (SlHDC-A core-ES) that is essential for fruit-specific expression of the SlHDC-A. To understand the molecular mechanisms of fruit-specific expression of the SlHDC-A promoter, we first identified the putative transcription factor binding elements in the SlHDC-A core promoter region and corresponding putative transcription factors which are highly expressed during fruit maturation. Yeast one hybrid analysis confirmed that GATA, HSF, and AP1 interact with the SlHDC-A core-ES promoter region. Further transactivation analysis revealed that expression of the three transcription factors significantly activated expression of a reporter gene driven by SlHDC-A core-ES promoter. These results suggest that GATA, HSF, and AP1 are involved in the fruit-specific expression of SlHDC-A promoter. Furthermore, the synthetic promoter composed of three tandem repeats of SlHDC-A core-ES showed relatively higher activity than the constitutive 35S promoter in the transgenic tomato fruits at the orange stage. Taken together, we propose a new synthetic promoter that is specifically expressed during fruit ripening stage.

Development of a Genome-Edited Tomato With High Ascorbate Content During Later Stage of Fruit Ripening Through Mutation of SlAPX4.

Ascorbate is an essential antioxidant substance for humans. Due to the lack of ascorbate biosynthetic enzyme, a human must intake ascorbate from the food source. Tomato is one of the most widely consumed fruits, thus elevation of ascorbate content in tomato fruits will improve their nutritional value. Here we characterized Solanum lycopersicum ASCORBATE PEROXIDASE 4 (SlAPX4) as a gene specifically induced during fruit ripening. In tomatoes, ascorbate accumulates in the yellow stage of fruits, then decreases during later stages of fruit ripening. To investigate whether SlAPX is involved in the decrease of ascorbate, the expression of SlAPXs was analyzed during fruit maturation. Among nine SlAPXs, SlAPX4 is the only gene whose expression was induced during fruit ripening. Mutation of SlAPX4 by the CRISPR/Cas9 system increased ascorbate content in ripened tomato fruits, while ascorbate content in leaves was not significantly changed by mutation of SlAPX4. Phenotype analysis revealed that mutation of SlAPX4 did not induce an adverse effect on the growth of tomato plants. Collectively, we suggest that SlAPX4 mediates a decrease of ascorbate content during the later stage of fruit ripening, and mutation of SlAPX4 can be used for the development of genome-edited tomatoes with elevated ascorbate content in fruits.

Microbiological survey of Korean mouse facilities from 2014 to 2019.

We surveyed mouse microbiological contamination rates by testing rates for common contaminants using serological, culture, and parasitological methods. A total of 21,292 experimentally housed mice from 206 animal facilities, including hospitals, universities, companies, and research institutes, were tested over a 6-year period from 2014 to 2019. The most commonly found contaminants were various species of nonpathogenic protozoa (47.2%). The most common pathogenic bacteria were Staphylococcus aureus (21.2%), Pasteurella pneumotropica (12.5%), and Pseudomonas aeruginosa (5.8%). Mouse hepatitis virus (6.1%) was detected, but no other viral or bacterial pathogens were found. These results establish that the main pathogens that currently contaminate mouse facilities in Korea are opportunistic pathogens and that contamination with important pathogens, such as those in Categories B or C, has decreased.

Patient discomfort levels during instrumentation procedure using nickel-titanium files with different kinetic movements.

This study evaluated the perceived vibration, noise and discomfort levels associated with two nickel-titanium file systems with different kinetics; reciprocating motion (REC) using WaveOne Gold and continuous rotation motion (CON) using ProTaper NEXT. Forty roots with two canals from maxillary premolar and molar of 40 patients were included. Root canals were instrumented using each system for each canal. Patients were surveyed about the vibration, noise and discomfort experienced using visual analogue scale, and their preference. The responses were statistically analysed using Wilcoxon Signed-Rank test, Mann-Whitney U test and Spearman's rank correlation test at the 95% of significance level. The vibration, noise and discomfort experienced were significantly greater in REC than CON (P < 0.05). In REC, male subjects reported significantly higher vibration than female (P < 0.05). Majority respondents (72.5%) preferred the CON method. The perceived vibration, noise and discomfort were less apparent from the CON than the REC.

A Backward Walking Training Program to Improve Balance and Mobility in Children with Cerebral Palsy.

BACKGROUND: We studied the effects of motor tasks using backward walking training on balance and gait functions of children with cerebral palsy. This was a single-blinded, randomized controlled trial with a crossover design conducted at a single facility. METHODS: Among 12 children with cerebral palsy, the forward (FWG) (n = 6) and backward walking groups (BWG) (n = 6) underwent training three times a week for 4 weeks, 40 min a day. After a 6-week break, the crossover training was conducted. Functional walking variables were measured. Time-Up-and-Go (TUG) test, Figure-8 Walk Test (FW8T), and Pediatric Balance Scale (PBS) were used for measuring balance. RESULTS: Both groups showed significant improvement in walking speed, stride length, and step length. The BWG demonstrated significant improvement in walking speed (p < 0.05) compared with the FWG. The TUG test, FW8T, and PBS showed significant improvement. After the 4-week intervention, both groups displayed a remarkable decrease in TUG duration and FW8T. Both groups also exhibited improvement in the PBS; more so in the BWG. CONCLUSIONS: Backward walking training with motor dual tasks could be a more effective interventional approach than forward walking training to improve balance and walking functions of children with spastic hemiplegia.

Trends and risk factors in severe hypoglycemia among individuals with type 2 diabetes in Korea.

AIMS: Because of the development of new classes of antidiabetic drugs, hypoglycemic events were expected to decrease. We investigated the trends and risk factors for severe hypoglycemia in subjects with type 2 diabetes in Korea. METHODS: We conducted repeated cross-sectional analyses using a Korean National Health Insurance Service-National Sample Cohort from 2006 to 2015. Severe hypoglycemia was defined as hospitalization or a visit to an emergency department with diagnosis of hypoglycemia using ICD-10 codes. RESULTS: During the study period, the prevalence of type 2 diabetes continuously increased. The percentage of patients prescribed metformin and dipeptidyl peptidase-4 inhibitor increased, while the use of sulfonylurea decreased considerably, especially since 2009. The proportion of patients prescribed ≥3 classes of drugs continually increased. Age-standardized incidence of severe hypoglycemia per 1000 patients with diabetes increased from 6.00 to 8.24 between 2006 and 2010, and then fell to 6.49 in 2015. Predictors of severe hypoglycemia included female, older age, comorbidities, polypharmacy, and sulfonylurea or insulin usage. CONCLUSIONS: Trends of severe hypoglycemia were associated with changes in drug classes rather than number of antidiabetic drugs. Relentless efforts to reduce the prescription of drugs with a high risk of hypoglycemia should be implemented, particularly for older women with multiple comorbidities.

Effect of posture control training using virtual reality program on sitting balance and trunk stability in children with cerebral palsy.

OBJECTIVE: We aimed to determine whether the posture control training in the sitting posture using virtual reality (VR) training program affects sitting balance and trunk stability in children with spastic cerebral palsy (CP). METHODS: The experiment was conducted for 4 weeks by randomly allocating 20 children with CP. The experimental group (n = 10) performed balance training in the sitting position using a VR training program, and the control group (n = 10) performed arm reach training in the sitting position. To evaluate static and dynamic sitting balance and trunk stability, the Wii Balance Board and Balancia software, the modified functional reach test, and the Korean version of the Trunk Control Measurement Scale were used. RESULTS: There were significant differences between the two groups in the changes in speed and postural swing distance before and after training (p < 0.05). The mFRT measurement showed significant differences in all directions before and after training between the two groups (p < 0.05). However, there was no significant difference between the two groups in the K-TCMS score. CONCLUSIONS: Posture control training in the sitting position using a VR training program was found to be more effective in improving the sitting balance and trunk stability of children with CP.

Optimization of the human colorectal carcinoma antigen GA733-2 production in tobacco plants.

The colorectal carcinoma-associated protein GA733-2 is one of the representative candidate protein for the development of plant-derived colorectal cancer vaccine. Despite of its significant importance for colorectal vaccine development, low efficiency of GA733-2 production limits its wide applications. To improve productivity of GA733-2 in plants, we here tested multiple factors that affect expression of recombinant GA733-2 (rGA733-2) and rGA733 fused to fragment crystallizable (Fc) domain (rGA733-Fc) protein. The rGA733-2 and rGA733-Fc proteins were highly expressed when the pBINPLUS vector system was used for transient expression in tobacco plants. In addition, the length of interval between rGA733-2 and left border of T-DNA affected the expression of rGA733 protein. Transient expression analysis using various combinations of Agrobacterium tumefaciens strains (C58C1, LBA4404, and GV3101) and tobacco species (Nicotiana tabacum cv. Xanthi nc and Nicotiana benthamiana) revealed that higher accumulation of rGA733-2 and rGA733-Fc proteins were obtained by combination of A. tumefaciens LBA4404 and Nicotiana benthamiana. Transgenic plants generated by introduction of the rGA733-2 and rGA733-Fc expression cassettes also significantly accumulated corresponding recombinant proteins. Bioactivity and stability of the plant-derived rGA733 and rGA733-Fc were evaluated by further in vitro assay, western blot and N-glycosylation analysis. Collectively, we here suggest the optimal condition for efficient production of functional rGA733-2 protein in tobacco system.

The ten amino acids of the oxygen-evolving enhancer of tobacco is sufficient as the peptide residues for protein transport to the chloroplast thylakoid.

KEY MESSAGE: The thylakoid transit peptide of tobacco oxygen-evolving enhancer protein contains a minimal ten amino acid sequences for thylakoid lumen transports. This ten amino acids do not contain twin-arginine, which is required for typical chloroplast lumen translocation. Chloroplasts are intracellular organelles responsible for photosynthesis to produce organic carbon for all organisms. Numerous proteins must be transported from the cytosol to chloroplasts to support photosynthesis. This transport is facilitated by chloroplast transit peptides (TPs). Four chloroplast thylakoid lumen TPs were isolated from Nicotiana tabacum and were functionally analyzed as thylakoid lumen TPs. Typical chloroplast stroma-transit peptides and thylakoid lumen transit peptides (tTPs) are found in N. tabacum transit peptides (NtTPs) and the functions of these peptides are confirmed with TP-GFP fusion proteins under fluorescence microscopy and chloroplast fractionation, followed by Western blot analysis. During the functional analysis of tTPs, we uncovered the minimum 10 amino acid sequence is sufficient for thylakoid lumen transport. These ten amino acids can efficiently translocate GFP protein, even if they do not contain the twin-arginine residues required for the twin-arginine translocation (Tat) pathway, which is a typical thylakoid lumen transport. Further, thylakoid lumen transporting processes through the Tat pathway was examined by analyzing tTP sequence functions and we demonstrate that the importance of hydrophobic core for the tTP cleavage and target protein translocation.

A cone-beam computed tomography study of the prevalence and location of the second mesiobuccal root canal in maxillary molars.

OBJECTIVES: This study aimed to investigate the incidence and location of the second mesiobuccal root (MB2) canal in maxillary molars with the aid of various measuring points and lines using cone-beam computed tomography (CT). MATERIALS AND METHODS: A total of 205 images of patients who underwent cone-beam CT examinations between 2011 and 2015 as part of their dental diagnosis and treatment were included. There were 76 images of the maxillary first molar and 135 images of the maxillary second molar. Canal orifices were detected at -1 mm from the top of the pulpal floor on cone-beam CT images. Image assessment was performed by 2 observers in reformatted image planes using software. Assessments included measurement of the distance between the MB1 and MB2 canals, and the angles between the lines connecting the MB1-MB2 and distobuccal (DB)-palatal (P) canals. The data were analyzed using the student's t-test. RESULTS: The prevalence of the MB2 canal was 86.8% in the first molar and 28.9% in the second molar. The angle between the lines connecting the MB1-MB2 and DB-P canals was 2.3° ± 5.7° in the first molar and -3.95° ± 7.73° in the second molar. The distance between the MB1 and MB2 canals was 2.1 ± 0.44 mm in the first molar and 1.98 ± 0.42 mm in the second molar. CONCLUSIONS: The angles between the lines connecting the MB1-MB2 and DB-P canals was almost parallel. These findings may aid in the prediction of the location of the MB2 canal orifice.

Comparison of vibration characteristics of file systems for root canal shaping according to file length.

OBJECTIVES: No studies have yet assessed vibration characteristics according to endodontic file length. Accordingly, the objective of the present study was to examine the vibration characteristics according to nickel-titanium file length and to compare these characteristics between different file systems. MATERIALS AND METHODS: A total of 45 root canal models were divided into 3 experimental groups (n = 15 each) based on the file system used (ProTaper Gold [PTG], ProTaper Next, or WaveOne Gold [WOG]). Each experimental group was further divided into 3 subgroups according to file length (21, 25, or 31 mm). An electric motor (X-SMART PLUS) was used in the experiment. For each file system, vibrations generated when using a size 25 file were measured and used to calculate the average vibration acceleration. The differences in vibrations were analyzed using 1-way analysis of variance and the Scheffé post hoc test with a confidence interval of 95%. RESULTS: In the PTG file system, significantly lower vibration acceleration was observed when using a 21-mm file than when using a 31-mm file. In the WOG file system, significantly stronger vibration acceleration was observed when using a 31-mm file than when using 21- or 25-mm files. Regardless of the file length, the WOG group exhibited significantly stronger vibration acceleration than the other 2 experimental groups. CONCLUSIONS: In clinical practice, choosing a file with the shortest length possible could help reduce vibrations. Additionally, consideration should be given to vibrations that could be generated when using WOG files with reciprocating motion.

Promoted ABA Hydroxylation by Capsicum annuum CYP707As Overexpression Suppresses Pollen Maturation in Nicotiana tabacum.

Abscisic acid (ABA) is a key signaling molecule that mediates plant response to stress. Increasing evidence indicates that ABA also regulates many aspects of plant development, such as seed germination, leaf development, and ripening. ABA metabolism, including ABA biosynthesis and degradation, is an essential aspect of ABA response in plants. In this study, we identified four cytochrome P450 genes (CaCYP707A1, 2, 3, and 4) that mediate ABA hydroxylation, which is required for ABA degradation in Capsicum annuum. We observed that CaCYP707A-mediated ABA hydroxylation promotes ABA degradation, leading to low levels of ABA and a dehydration phenotype in 35S:CaCYP707A plants. Importantly, seed formation was strongly inhibited in 35S:CaCYP707A plants, and a cross-pollination test suggested that the defect in seed formation is caused by improper pollen development. Phenotypic analysis showed that pollen maturation is suppressed in 35S:CaCYP707A1 plants. Consequently, most 35S:CaCYP707A1 pollen grains degenerated, unlike non-transgenic (NT) pollen, which developed into mature pollen grains. Together our results indicate that CaCYP707A mediates ABA hydroxylation and thereby influences pollen development, helping to elucidate the mechanism underlying ABA-regulated pollen development.