The Arabidopsis katamari2 Mutant Exhibits a Hypersensitive Seedling Arrest Response at the Phase Transition from Heterotrophic to Autotrophic Growth

Young seedlings use nutrients stored in the seeds to grow and acquire photosynthetic potential. This process, called seedling establishment, involves a developmental phase transition from heterotrophic to autotrophic growth. Some membrane-trafficking mutants of Arabidopsis (Arabidopsis thaliana), such as the katamari2 (kam2) mutant, exhibit growth arrest during seedling development, with a portion of individuals failing to develop true leaves on sucrose-free solid medium. However, the reason for this seedling arrest is unclear. In this study, we show that seedling arrest is a temporal growth arrest response that occurs not only in kam2 but also in wild-type (WT) Arabidopsis; however, the threshold for this response is lower in kam2 than in the WT. A subset of the arrested kam2 seedlings resumed growth after transfer to fresh sucrose-free medium. Growth arrest in kam2 on sucrose-free medium was restored by increasing the gel concentration of the medium or covering the surface of the medium with a perforated plastic sheet. WT Arabidopsis seedlings were also arrested when the gel concentration of sucrose-free medium was reduced. RNA sequencing revealed that transcriptomic changes associated with the rate of seedling establishment were observed as early as 4 d after sowing. Our results suggest that the growth arrest of both kam2 and WT seedlings is an adaptive stress response and is not simply caused by the lack of a carbon source in the medium. This study provides a new perspective on an environmental stress response under unfavorable conditions during the phase transition from heterotrophic to autotrophic growth in Arabidopsis.

Stomatal regulators are co-opted for seta development in the astomatous liverwort Marchantia polymorpha

The evolution of special types of cells requires the acquisition of new gene regulatory networks controlled by transcription factors (TFs). In stomatous plants, a TF module formed by subfamilies Ia and IIIb basic helix-loop-helix TFs (Ia-IIIb bHLH) regulates stomatal formation; however, how this module evolved during land plant diversification remains unclear. Here we show that, in the astomatous liverwort Marchantia polymorpha, a Ia-IIIb bHLH module regulates the development of a unique sporophyte tissue, the seta, which is found in mosses and liverworts. The sole Ia bHLH gene, MpSETA, and a IIIb bHLH gene, MpICE2, regulate the cell division and/or differentiation of seta lineage cells. MpSETA can partially replace the stomatal function of Ia bHLH TFs in Arabidopsis thaliana, suggesting that a common regulatory mechanism underlies setal and stomatal formation. Our findings reveal the co-option of a Ia-IIIb bHLH TF module for regulating cell fate determination and/or cell division of distinct types of cells during land plant evolution.

Comprehensive analysis of peptide-coding genes and initial characterization of an LRR-only microprotein in Marchantia polymorpha

In the past two decades, many plant peptides have been found to play crucial roles in various biological events by mediating cell-to-cell communications. However, a large number of small open reading frames (sORFs) or short genes capable of encoding peptides remain uncharacterized. In this study, we examined several candidate genes for peptides conserved between two model plants: Arabidopsis thaliana and Marchantia polymorpha. We examined their expression pattern in M. polymorpha and subcellular localization using a transient assay with Nicotiana benthamiana. We found that one candidate, MpSGF10B, was expressed in meristems, gemma cups, and male reproductive organs called antheridiophores. MpSGF10B has an N-terminal signal peptide followed by two leucine-rich repeat (LRR) domains and was secreted to the extracellular region in N. benthamiana and M. polymorpha. Compared with the wild type, two independent Mpsgf10b mutants had a slightly increased number of antheridiophores. It was revealed in gene ontology enrichment analysis that MpSGF10B was significantly co-expressed with genes related to cell cycle and development. These results suggest that MpSGF10B may be involved in the reproductive development of M. polymorpha. Our research should shed light on the unknown role of LRR-only proteins in land plants.

POS1423 CHARACTERISTICS OF CYTOMEGALOVIRUS-POSITIVE VERSUS NEGATIVE, AND CYTOMEGALOVIRUS-TREATED VERSUS UNTREATED PATIENTS DURING IMMUNOSUPPRESSIVE THERAPY FOR RHEUMATIC DISEASES

Background

Immunosuppressive treatment is a common cause of cytomegalovirus (CMV) reactivation.

Objectives

To elucidate the characteristics of CMV-positive and negative patients during the treatment for rheumatic diseases.

Methods

We retrospectively evaluated consecutive patients admitted to our department from January 2006 to October 2021 whose C7-HRP antigen were measured. We collected their age, sex, primary problem and its lesion, and test results within 3 months before C7-HRP measurement. We also investigated the use of immunosuppressants, and maximum and cumulative dose of administered prednisolone within 6 months before C7-HRP measurement. Maximum and cumulative dose of prednisolone contained methylprednisolone pulse, which was converted into prednisolone equivalent. We investigated the characteristics of CMV-positive and negative patients, and those of CMV-positive patients with or without anti-CMV drug use.

Results

Of a total of 472 patients, 85 were positive and 387 were negative for C7-HRP. The average age was 71.2 vs. 64.4 (p=0.0021). Their male-to-female ratio was 20/65 vs. 120/267 (p=0.0290). The following diseases were significantly common among CMV-positive patients: microscopic polyangiitis (21.2% vs. 3.9%, p<0.0001), adult-onset Still’s disease (7.1% vs. 1.3%, p=0.0002), and systemic sclerosis (4.7% vs. 2.1%, p=0.0273). Significantly common comorbidities of CMV-positive patients were interstitial lung disease (35.3% vs. 16.0%, p<0.0001), nephritis (23.5% vs. 11.6%, p=0.0005), peripheral nervous system disorders (11.8% vs. 5.7%, p=0.0070), alveolar hemorrhage (5.9% vs. 0.8%, p=0.0001), and peripheral circulatory disorders (4.7% vs. 1.6%, p=0.0111). Average neutrophil counts (7720 /μL vs. 6440 /μL, p=0.0001), serum creatinine (1.0 mg/dL vs. 0.9 mg/dL, p=0.0104), and hemoglobin A1c (6.3% vs. 5.7%, p=0.0030) were significantly higher among CMV-positive patients, whereas hemoglobin (10.1 g/dL vs. 11.1 g/dL, p<0.0001), lymphocyte counts (820 /μL vs. 1190 /μL, p<0.0001), platelet counts (233000 /μL vs. 259000 /μL, p<0.0001), and serum albumin (2.9 g/dL vs. 3.4 g/dL, p<0.0001) were lower. Higher maximum dose of prednisolone (534.9 mg/day vs. 135.5 mg/day, p<0.0001), intravenous cyclophosphamide (27.1% vs. 11.4%, p<0.0001), rituximab (9.4% vs. 2.1%, p<0.0001), azathioprine (23.5% vs. 14.2%, p=0.0053), cyclosporin (8.2% vs. 3.6%, p=0.0101) were significantly more often used among CMV-positive patients. Average cumulative dose of prednisolone was 3022.6 mg vs. 1408.7 mg (p<0.0001). We also performed multivariate analysis, including the patients’ age, sex, maximum and cumulative dose of prednisolone, and the use of intravenous cyclophosphamide, rituximab, azathioprine, and cyclosporin. Elderly (p=0.0006), female (p=0.0293), high cumulative dose of prednisolone (p=0.0155), and the use of cyclosporin (p=0.0479) were significantly associated with CMV-positivity. Anti-CMV drug was administered to 63.5% of CMV-positive patients. The average age was significantly higher in anti-CMV-drug-treated patients than untreated patients (73.7 vs. 67.1, p=0.0492). The CMV-treated patients had significantly higher neutrophil counts (8540 /μL vs. 6280 /μL, p<0.0001), erythrocyte sedimentation rate (57.6 mm/h vs. 40.5 mm/h, p<0.0001), and C-reactive protein (5.3 mg/dL vs. 2.6 mg/dL, p<0.0001) than the untreated patients while the other data such as complete blood counts and serum chemistry revealed no significant difference. Average maximum dose of prednisolone was significantly higher in CMV-treated patients (617.1 mg/day vs. 391.1 mg/day, p=0.0261) while average cumulative dose of prednisolone and the use of any other immunosuppressants revealed no significant difference.

Conclusion

Intense immunosuppression, especially with higher dose of glucocorticoids, seemed to be the major risk factor of CMV reactivation. These medications may often require anti-CMV therapy.

Disclosure of Interests

None declared

AB0298 THE RISK OF SULPHA ALLERGY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Sulpha drugs have been used such as sulfasalazine for the treatment of rheumatoid arthritis (RA), and trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment or prevention of pneumocystis pneumonia. However, some patients with RA delay treatment because of allergy to sulpha drugs[1]. We reported that 16.7% of RA patients presented drug allergies[2]. It was not clear what is a risk factor for drug allergies in patients with RA.

Objectives

The aim of this study was to evaluate the clinical features with sulpha allergy in patients with RA.

Methods

We prospectively examined consecutive patients diagnosed with RA in our hospital from March 2021 to January 2022. The patients with RA met the EULAR/ACR 2010 criteria. We included patients with RA with other rheumatic diseases. A careful allergic history was obtained from patients with RA and physical examination performed.

The first analysis was performed on patient baseline laboratory data at diagnosis of patients with RA with or without sulpha allergy. Sulpha allergy (rash, angioedema and anaphylaxis after drug exposure) was allergy to sulfasalazine or TMP-SMX. The second analysis was performed on seven types of allergic reactions: (1) drug allergies other than sulpha drugs (rash, angioedema and anaphylaxis after drug exposure), (2) food allergy (rash, angioedema and anaphylaxis after foods exposure), (3) allergic contact dermatitis such as metals, and other cosmetics, (4) seasonal allergic rhinitis and/or conjunctivitis (AR and/or AC), and AR and/or AC associated with house dust, (5) asthma, and (6) atopic dermatitis.

Results

There were 513 patients with RA in our study. In the first analysis, 17 patients with sulpha allergy and 496 patients without sulpha drugs were enrolled (Table 1). The median ages (with supha allergy and without sulpha allergy) were 66.0 and 72.0 years old (p=0.40). Females were 82.3% and 77.0%(p=0.4). The median observation period was 97.0 and 69.0 months (p=0.20). Patients with other rheumatic diseases were 11.6 and 6.8% (p=0.34).

Table 1.

Characteristics of RA patients at diagnosis of RA

With sulpha allergy (n = 17)Without sulpha allergy (n = 496)PFemale83.4%76.9%0.77Age, year, y66.0 (56.0-78.5)72.0 (60.0-80.0)0.40Observation period, m97.0 (45.5-182.0)69.0 (31.0-123.8)0.20Patients with other rheumatic diseases11.8%6.8%0.34ANA-positive patients(>1:80)52.9%28.2%0.052Anti-SSA antibody-positive patients46.2%18.2%0.02RF-positive patients40.0%66.8%0.049

The RA patients with sulpha allergy had higher positivity rate of anti-nuclear antibody (ANA) (>1:80) (52.9%, 28.2%: p=0.052), higher positivity rate of anti–Sjögren’s-syndrome-related antigen A autoantibody (anti-SSA antibody) than those without sulpha allergies (46.2%, 18.2%: p = 0.02) and lower positivity rate of rheumatoid factor(RF) than those without sulpha allergies (40.0%, 66.8%: p = 0.049).

In the second analysis drug allergies other than sulpha allergy were more frequent in patients with sulpha allergy. Drug allergies other than sulpha allergy were such as antibiotics and nonsteroidal anti-inflammatory drugs. There were no significant differences in other allergies.

Conclusion

Among patients with RA, patients with sulpha allergy had higher positivity rate of ANA and anti-SSA antibody, and lower positivity rate of RF than those without sulpha allergy. RA patients with sulpha allergy had a higher prevalence of the other drug allergies than those other than sulpha allergy.

References

[1]Konishi MH et al. Allergic diseases in adult-onset Still’s disease and rheumatoid arthtitis. Arerugi. 2021; 70: 965-975.

[2]Konishi MH et al. Allergic Disorders and Drug Allergies in Primary Sjögren’s Syndrome and Rheumatoid Arthritis. EULAR 2021.

Disclosure of Interests

None declared

Patterns of nesting behaviour and nesting success for green turtles at Raine Island, Australia

To understand how turtles use the nesting habitat at Raine Island across a nesting season, and how the turtles respond to the restoration of the island’s dune systems, we identified 534 nesting events for 39 green turtles Chelonia mydas across 2 breeding seasons using data derived from satellite tags. Tracked turtles laid between 4 and 10 clutches of eggs. Patterns of nesting success varied between individuals, within and between seasons. Nesting success was higher in 2018-19 (57%) than 2017-18 (45%), and in both years, nesting success was lowest between October and early January (<50%). In 2017-18, increased rainfall in January corresponded with increased nesting success (>50%). The density of female turtles ashore was lower in 2018-19, and likely explains higher nesting success in 2018-19 because competition for nest space was lower. In 2017-18, females had more attempts per clutch, and the attempts were around 90 min longer. Consequently, energy required to lay a clutch of eggs in 2017-18 was significantly higher than in 2018-19, highlighting potential costs of lower nesting success rates on reproductive output. The area of beach re-profiled as an intervention in 2014 and 2017 was a nesting hotspot in 2017-18. However, in 2018-19, the area was not used to the same extent, and the nesting hotspot occurred on the north-eastern unaltered beach. Collectively, the tracking of turtles across the whole nesting season enabled us to assess overall beach use and nesting site fidelity of green turtles at Raine Island. Results will aid future planning and management of beach restoration activities at turtle nesting sites.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Spatiotemporal relationship between auxin dynamics and hydathode development in Arabidopsis leaf teeth

Hydathode is a plant tissue of vascular plants involved in water release called guttation. Arabidopsis hydathodes are found at the tips of leaf teeth and contain three major components: water pores, xylem ends, and small cells. Leaf teeth are known as the main parts for auxin biosynthesis and accumulation during leaf development. However, the detailed spatiotemporal relationship between auxin dynamics and hydathode development is unknown. In this study, we show that auxin biosynthesis and accumulation precede hydathode development. A triple marker line (called YDE line) containing three leaf tooth markers: YUC4:nls-3xGFP (auxin biosynthesis), DR5rev:erRFP (auxin accumulation or maxima), and E325-GFP (hydathode development), was generated, and spatiotemporal confocal microscopic analysis was carried out. The expression area of these markers became larger during leaf development, implying that the hydathode size enlarges as the leaf tooth grows. Detailed observation revealed that the auxin-related markers YUC4:nls-GFP and DR5rev:erRFP were first expressed in the early stage of leaf tooth growth. Then, E325-GFP was expressed partly overlapping with the auxin markers at a later stage. These findings provide new insights into the spatiotemporal relationship between auxin dynamics and hydathode development in Arabidopsis.

Fluorescent protein-based imaging and tissue-specific RNA-seq analysis of Arabidopsis hydathodes

Hydathodes are typically found at leaf teeth in vascular plants and are involved in water release to the outside. Although morphological and physiological analysis of hydathodes has been performed in various plants, little is known about the genes involved in hydathode function. In this study, we performed fluorescent protein-based imaging and tissue-specific RNA-seq analysis in Arabidopsis hydathodes. We used the enhancer trap line E325, which has been reported to express green fluorescent protein (GFP) at its hydathodes. We found that E325-GFP was expressed in small cells found inside the hydathodes (named E cells) that were distributed between the water pores and xylem ends. No fluorescence of the phloem markers pSUC2:GFP and pSEOR1:SEOR1-YFP was observed in the hydathodes. These observations indicate that Arabidopsis hydathodes are composed of three major components: water pores, xylem ends, and E cells. In addition, we performed transcriptome analysis of the hydathode using the E325-GFP line. Microsamples were collected from GFP-positive or -negative regions of E325 leaf margins with a needle-based device (~130 µm in diameter). RNA-seq was performed with each single microsample using a high-throughput library preparation method called Lasy-Seq. We identified 72 differentially expressed genes. Among them, 68 genes showed significantly higher and four genes showed significantly lower expression in the hydathode. Our results provide new insights into the molecular basis for hydathode physiology and development.

Early restenosis and late catch-up phenomenon after newer biodegradable- and durable-polymer drug-eluting stent implantations

Background

It is yet to be known whether mechanisms underlying restenosis in newer-generation durable-polymer (DP) and biodegradable-polymer (BP) drug-eluting stents (DES) are different.

Purpose

This study aims to assess the incidences and predictors of early restenosis and late catch-up phenomenon after newer-generation durable-polymer (DP) and biodegradable-polymer (BP) DES.

Methods

Between 2010 and 2017, 13858 lesions in 6350 patients were treated with DES (4393 BP-DES, 9465 DP-DES). The early-term (within 1 year) and late-term (from 1 to 2 years) follow-up angiographies were scheduled. Late catch-up phenomenon was defined as in-stent restenosis (ISR) in lesions that evaded ISR within 1 year after stent implantation. ISR was defined as angiographic restenosis of more than 50%.

Results

The mean patient age was 71 years, and 76.7% were male. Early-term angiographies were performed in 10955 lesions (79.0%). Of those without early-term ISR, late-term angiographies were performed in 7771 lesions (56.1%). The incidences of mid-term restenosis and late catch-up phenomenon were 6.6% and 3.9%, respectively.

In the multivariate regression analyses, history of diabetes, hemodialysis and previous PCI were independent predictors of both early restenosis and late catch-up phenomenon. Also, some lesion characteristics such as chronic total occlusion, right coronary artery ostial lesion, small vessel (defined as reference diameter &lt;2.5mm), long lesion (defined as lesion length &gt;30mm) and treatment of ISR lesion were independent predictors of both early restenosis and late catch-up phenomenon.

Bifurcation lesion and heavily calcified lesion treated with rotablator were independent risk of early restenosis. Bypass graft lesion was an independent predictor of late catch-up phenomenon.

Early restenosis was observed less frequently in DP-DES than in BP-DES (6.3% versus 7.4%, P=0.012). On the contrary, late catch-up phenomenon was observed more frequently in DP-DES than in BP-DES (4.3% versus 2.9%, P=0.026).

Conclusions

Some lesion characteristics were independent predictors of early restenosis and late catch-up phenomenon after newer-generation DES implantation. The deployment of BP-DES resulted in more early restenosis and less late catch-up phenomenon compared to that of DP-DES.

Early Restenosis and Late Catch-Up

Funding Acknowledgement

Type of funding source: None

Clinical features and prognosis of acute myocardial infarction due to coronary artery embolism

Background

Coronary artery embolism (CE) is one of the important causes of acute coronary syndrome (ACS). The feature of CE is that angiographic evidence of coronary artery embolism and thrombosis without atherosclerotic components. However, the prevalence of CE remains unknown because of the diffifulty to diagnose in the acute settings. A recent retrospective analysis suggested that up to 3% of ACS cases may result from CE.

Purpose

The aim of this study was to elucidate the prevalence, clinical features and long-term outcomes including all-cause and cardiac death.

Methods

We analysed the consecutive 2695 patients with first AMI performed coronary intervention between January 2004 and July 2017. CE was diagnosed by clinical histories and angiographic findings. We retrospectively evaluated the clinical and lesion characteristics and outcomes including all-cause and cardiac death.

Results

The prevalence of CE was 2.0% (n=55; CE group and n=2640; non-CE group), including 8 (15%) patients with multivessel CE. The CE group had higher average age (70.8±14.9 vs. 68.4±12.6, p&lt;0.01), prevalence of female (54% vs. 27%, p&lt;0.01), lower prevalence of smoking (34% vs. 62%, p&lt;0.01). The common causes with CE were atrial fibrillation (47%), and malignant tumor (9%), and cardiomyopathy (5%), and patent foramen ovale (4%). Only 20% of patients with CE were treated with anti-coagulant therapy. The rate of distal infarction site (defined as #4, #8, #14–15) was significantly higher in CE group than non-CE group (54.0% vs. 4.9%, p&lt;0.01). During median follow-up of 53.6 [32.6–77.3] months, CE and thromboembolism recurred in 5 patients (CE: 1 patient, stroke 4 patients). The 4-year incidence of all-cause death was significantly higher in the CE group, but cardiac death was not significantly different between the groups (28.8% vs. 14.8%, p=0.03; 12.8% vs. 5.1%, p=0.11).

Conclusion

Compared with non-CE group, the prevalence of distal infarction site was significantly higher in the CE group, and the incidence of cardiac death is not significantly different.

Funding Acknowledgement

Type of funding source: None

Risk stratification based on academic research consortium high bleeding risk criteria for long-term bleeding event after everolimus-eluting stent implantation

Background

Recently, the Academic Research Consortium for High Bleeding Risk (ARC-HBR) criteria has been suggested as the standard definition of HBR.

Purpose

We aimed to investigate the risk stratification based on ARC-HBR Criteria for long-term bleeding event after everolimus-eluting stent implantation

Methods

The study population comprised 1193 patients treated with EES without in-hospital event between 2010 and 2011. Individual ARC-HBR criteria was retrospectively assessed. Major bleeding were defined as the occurrence of a Bleeding Academic Research Consortium type 3 or 5 bleeding event. The mean follow-up period was 2996±433 days.

Results

There were 656 patients (55.0%) in HBR-groups. Cumulative incidence of major bleeding was significantly higher in HBR-group (8.1% vs 3.4% at 4 year, and 16.2% vs 5.7% at 8 year, P&lt;0.001). Cumulative rate of major bleeding tend to be higher as the number of ARC-HBR criteria increased (≥2 Majors: 24.3%, 1 Major: 17.0%, ≥2 Minors:11.7%, and Non-HBR: 5.7%, P&lt;0.001).

Conclusion

ARC-HBR criteria successfully stratified the long-term bleeding risk after drug-eluting stent implantation in real-world practice.

Funding Acknowledgement

Type of funding source: None

Higher Stomatal Density Improves Photosynthetic Induction and Biomass Production in Arabidopsis Under Fluctuating Light

Stomatal density (SD) is closely associated with photosynthetic and growth characteristics in plants. In the field, light intensity can fluctuate drastically within a day. The objective of the present study is to examine how higher SD affects stomatal conductance (g s ) and CO2 assimilation rate (A) dynamics, biomass production and water use under fluctuating light. Here, we compared the photosynthetic and growth characteristics under constant and fluctuating light among three lines of Arabidopsis thaliana (L.): the wild type (WT), STOMAGEN/EPFL9-overexpressing line (ST-OX), and EPIDERMAL PATTERNING FACTOR 1 knockout line (epf1). ST-OX and epf1 showed 268.1 and 46.5% higher SD than WT (p < 0.05). Guard cell length of ST-OX was 10.0% lower than that of WT (p < 0.01). There were no significant variations in gas exchange parameters at steady state between WT and ST-OX or epf1, although these parameters tended to be higher in ST-OX and epf1 than WT. On the other hand, ST-OX and epf1 showed faster A induction than WT after step increase in light owing to the higher g s under initial dark condition. In addition, ST-OX and epf1 showed initially faster g s induction and, at the later phase, slower g s induction. Cumulative CO2 assimilation in ST-OX and epf1 was 57.6 and 78.8% higher than WT attributable to faster A induction with reduction of water use efficiency (WUE). epf1 yielded 25.6% higher biomass than WT under fluctuating light (p < 0.01). In the present study, higher SD resulted in faster photosynthetic induction owing to the higher initial g s . epf1, with a moderate increase in SD, achieved greater biomass production than WT under fluctuating light. These results suggest that higher SD can be beneficial to improve biomass production in plants under fluctuating light conditions.

Apple latent spherical virus (ALSV)-induced gene silencing in a medicinal plant, Lithospermum erythrorhizon

Lithospermum erythrorhizon is a medicinal plant that produces shikonin, a red lipophilic naphthoquinone derivative that accumulates exclusively in roots. The biosynthetic steps required to complete the naphthalene ring of shikonin and its mechanism of secretion remain unclear. Multiple omics studies identified several candidate genes involved in shikonin production. The functions of these genes can be evaluated using virus-induced gene silencing (VIGS) systems, which have been shown advantageous in introducing iRNA genes into non-model plants. This study describes the development of a VIGS system using an apple latent spherical virus (ALSV) vector and a target gene, phytoene desaturase (LePDS1). Virus particles packaged in Nicotiana benthamiana were inoculated into L. erythrorhizon seedlings, yielding new leaves with albino phenotype but without disease symptoms. The levels of LePDS1 mRNAs were significantly lower in the albino plants than in mock control or escape plants. Virus-derived mRNA was detected in infected plants but not in escape and mock plants. Quantitative PCR and deep sequencing analysis indicated that transcription of another hypothetical PDS gene (LePDS2) also decreased in the defective leaves. Virus infection, however, had no effect on shikonin production. These results suggest that virus-based genetic transformation and the VIGS system silence target genes in soil-grown L. erythrorhizon.

Dynamic Capture and Release of Endoplasmic Reticulum Exit Sites by Golgi Stacks in Arabidopsis

Protein transport from the endoplasmic reticulum (ER) to Golgi stacks is mediated by the coat protein complex COPII, which is assembled at an ER subdomain called ER exit site (ERES). However, the dynamic relationship between ERESs and Golgi stacks is unknown. Here, we propose a dynamic capture-and-release model of ERESs by Golgi stacks in Arabidopsis thaliana. Using variable-angle epifluorescence microscopy with high-temporal-resolution imaging, COPII-component-bound ERESs were detected as punctate structures with sizes of 300–500 nm. Some punctate ERESs are distributed on ER tubules and sheet rims, whereas others gather around a Golgi stack in an ER-network cavity to form a beaded-ring structure. Free ERESs that wander into an ER cavity are captured by a Golgi stack in a cytoskeleton-independent manner. Then, they are released by the Golgi stack for recycling. The dynamic ERES cycling might contribute to efficient transfer of de novo synthesized cargo proteins from the ER to Golgi stacks.

•

VAEM images show dynamic behavior of minimal punctate ERESs

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Most of punctate ERESs are distributed on the ER network tubes

•

Several punctate ERESs contact with a Golgi stack in an ER network cavity

•

ERESs are dynamically captured and released by Golgi stacks

Arabidopsis ECHIDNA protein is involved in seed coloration, protein trafficking to vacuoles, and vacuolar biogenesis

Flavonoids are a major group of plant-specific metabolites that determine flower and seed coloration. In plant cells, flavonoids are synthesized at the cytosolic surface of the endoplasmic reticulum and are sequestered in the vacuole. It is possible that membrane trafficking, including vesicle trafficking and organelle dynamics, contributes to flavonoid transport and accumulation. However, the underlying mechanism has yet to be fully elucidated. Here we show that the Arabidopsis ECHIDNA protein plays a role in flavonoid accumulation in the vacuole and protein trafficking to the vacuole. We found defective pigmentation patterns in echidna seed, possibly caused by reduced levels of proanthocyanidins, which determine seed coloration. The echidna mutant has defects in protein sorting to the protein storage vacuole as well as vacuole morphology. These findings indicate that ECHIDNA is involved in the vacuolar trafficking pathway as well as the previously described secretory pathway. In addition, we found a genetic interaction between echidna and green fluorescent seed 9 (gfs9), a membrane trafficking factor involved in flavonoid accumulation. Our findings suggest that vacuolar trafficking and/or vacuolar development, both of which are collectively regulated by ECHIDNA and GFS9, are required for flavonoid accumulation, resulting in seed coat pigmentation.

Structural and functional relationships between plasmodesmata and plant endoplasmic reticulum-plasma membrane contact sites consisting of three synaptotagmins

Synaptotagmin 1 (SYT1) has been recognised as a tethering factor of plant endoplasmic reticulum (ER)-plasma membrane (PM) contact sites (EPCSs) and partially localises to around plasmodesmata (PD). However, other components of EPCSs associated with SYT1 and functional links between the EPCSs and PD have not been identified. We explored interactors of SYT1 by immunoprecipitation and mass analysis. The dynamics, morphology and spatial arrangement of the ER in Arabidopsis mutants lacking the EPCS components were investigated using confocal microscopy and electron microscopy. PD permeability of EPCS mutants was assessed using a virus movement protein and free green fluorescent protein (GFP) as indicators. We identified two additional components of the EPCSs, SYT5 and SYT7, that interact with SYT1. The mutants of the three SYTs were defective in the anchoring of the ER to the PM. The ER near the PD entrance appeared to be weakly squeezed in the triple mutant compared with the wild-type. The triple mutant suppressed cell-to-cell movement of the virus movement protein, but not GFP diffusion. We revealed major additional components of EPCS associated with SYT1 and suggested that the EPCSs arranged around the PD squeeze the ER to regulate active transport via PD.

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

P1307 An echocardiographic observation over the disappearing process of the prosthetic valve thrombus caused by the inflammatory hypercoagulability; a case report

Background

Whenever fever and inflammatory reaction continue for a while in the patients with a prosthetic valve, than usual, we must keep infective endocarditis in mind. On the other hand, inflammation and thrombosis are well known to coexist often. There are several reports of thrombotic valves associated with inflammation-activated hypercoagulability. Furthermore, C-reactive protein (CRP) has been reported to imply an increased risk of thrombus especially in the presence of an injury on the prosthetic valve.

Case report

We report a case of a 70-year-old male with a leaflet thrombus on the bioprosthetic aortic valve. He suffered from fever, and symptoms of heart failure and was hospitalized for treatment. Blood tests presented that white blood cell count was 4900/μL (neutrophil 81.1%) and CRP 10.82 mg/dL. Infectious endocarditis (IE) was suspected. Transthoracic echocardiography (TTE) was per-formed, however, vegetation and abscess were not found. Noteworthily, the bioprosthetic valve leaflet on the right coronary cusp showed thickening and opening dysfunction (Figure A, parasternal short axis). Mean pressure gradient (mPG) through the aortic valve was 15mmHg and peak velocity (Vmax) 2.7m/s. Blood culture was negative, and his body temperature and CRP were improved by empirical antibiotic administration. The anticoagulation therapy with warfarin was started, he was discharged from the hospital and followed up in the outpatient clinic. TTE after the initiation of anticoagulation therapy, did not reveal any more dysfunction on the bioprosthetic valve (mPG: 9mmHg, Vmax: 2.2m/s) (Figure B, parasternal short axis). The diagnostic and therapeutic process of this case implied success. The opening-dysfunction of prosthetic valve leaflets was reversible and therefore, we concluded that the thickening of the prosthetic valve could be attributed to thrombus adhesion. Computed Tomography (CT) was not performed because he suffered from chronic kidney disease.

Conclusion

Surely, CT is very useful for the evaluation of thrombotic valves in the patients in whom it is permissible to use contrast agent. However, we could successfully evaluate the recovery process of leaflet thrombosis by echocardiography because of a difficult reason of CT use in this case. The prolongation of inflammatory reaction in the patients with a prosthetic valve should keep IE in mind in everyday life. Even if the findings of bacterial infection are obscure, it is more and more important to observe carefully the change of leaflets, whenever an open-dysfunction and a thrombus adhesion of the prosthetic valves exist.

Abstract P1307 Figure.

P702 An unusual echocardiographic finding of protrusive vegetation caused by perivalvular abscess perforation into the left atrium

Background

It is well-known that Infective endocarditis (IE) caused by S. aureus progresses rapidly and is highly destructive. The most often abscess formation after aortic valve replacement (AVR) is the mitral-aortic intervalvular fibrosa (MAIVF). It is difficult to cure MAIVF radically once infection occurs, and then the abscess tends to spread. After abscess formation is once established, IE tends to be widespread, the prognosis is definitely poor unless surgical repairment is executed, and then an emergency surgery is essential and unavoidable for complete cure. We report an unusual case of aortic valve abscess with perforation of vegetation into the left atrium after aortic valve replacement.

Case report

A 77-year-old man underwent the bioprosthetic AVR for aortic valve stenosis one month ago. On the 9th day after discharge, he visited the hospital for the follow-up. At the time, the body temperature was 36.6 ° C, the blood pressure 133/50 mmHg, white blood cell count 10500/μL, and C-reactive protein 3.31 mg/dL. Transthoracic echocardiography (TTE) demonstrated the perivalvular abscesses on the prosthetic aortic valve and mass structures attached to the MAIVF in the left atrium (Figure A, C). He was hospitalized again and had an emergency re-operation. Intraoperative transesophageal echocardiography (TEE) showed a perivalvular abscess on the prosthetic valve, and a high-intensity structure (vegetation like) protruding from the Valsalva Sinus into the left atrium of the MAIVF (Figure B, D). Surgical findings did not reveal any wart on the native valve itself. One-third of the annulus was disrupted. The subvalvular tissue all around was abscessed. Notably, the abscess cavity between NCC and LCC reached MAIVF of the anterior mitral leaflet, and the structure projecting to the left atrium was vegetation. In this case, TTE pointed out a perivalvular abscess of the aortic valve, IE was suspected at the time of outpatient visit at an early stage after discharge, and the spread of inflammation was observed with a high speed beyond the expectation at the time of operation.

Conclusion

Early after the operation, TTE revealed a mass was protruded into the left atrium. Generally, vegetation is soft and flexible in itself. However, in this case, the vegetation was less mobile, and for that reason, abscesses or tumors were suspected. TEE enabled us to obtain anatomically more detailed information and to foresee the left atrial wall repairment at the time of reoperation. We reported an unusual case of IE with solid vegetation attached to the wall and difficult to diagnose.

Abstract P702 Figure.

P248 Changes of atrial septum defect caused by posture during three-dimensional transesophageal echocardiography ( a case of Platypnea-orthodeoxia syndrome)

Background

Platypnea-Orthodeoxia syndrome (POS) is a rare phenomenon which is characterized postural hypoxia due to the intracardiac shunt from right to left through a patent foramen ovale, an atrial septal defect or a pulmonary arteriovenous malformation. POS is often underestimated because the hypoxia by postural change is difficult to be detected. We evaluated three-dimensional transesophageal echocardiography (TEE) to diagnose POS in an elderly patient.

Case report

A 84-year-old woman suffered from repetitive syncope for several years. She undertook twelve leads electrocardiogram (ECG), screening transthoracic echocardiography (TTE), twenty-four hours ECG and treadmill stress ECG, however, the cause of syncope was not identified. After another syncope event happened, she was transferred to the emergency room. Then, the hypoxia caused by sitting position was pointed out for the first time.

Her hypoxia was improved by supine position and oxygen administration. TTE demonstrated no right heart enlargement. Shunt flow was suspected on her atrial septum; however, it was difficult to reveal it by TTE because of her obesity. Therefore, she underwent intravenous saline injection test. In the decubitus position, an intravenous injection of saline under Valsalva maneuver revealed the shunt flow from the right atrium to the left atrium. Her arterial oxygen saturation (SpO2) was 95%. In the sitting position, a visible shunt flow was observed, then her SpO2 dropped to 85%. By TEE, the shunt hole was found in the oval fossa of the atrial septum. TEE was evaluated by different positions. The atrial defect hole became larger in the sitting position (area 1.05cm2) than in the supine position (area 0.43cm2). As a result, the postural change to sitting revealed Platypnea-Orthodeoxia syndrome associated with ASD. The pulmonary blood flow/systemic blood flow ratio (Qp/Qs) was estimated at 1.6. After surgical ASD closure, she was discharged without any symptoms.

Conclusion

Unclearness of TTE and the absence of a right heart overload may lead to misdiagnosis of POS. If a syncope patient caused hypoxia in the only sitting position, detailed echocardiography should be needed to rule out a diagnosis of POS. This is considerably valuable case of three-dimensional TEE confirmed the changes of ASD size by postural change.

Abstract P248 Figure.

P1472 Concealed thrombus in a 12-year-old boy diagnosed by disappearance of intricate comb-like pectinate muscle form in the left atrial appendage

Background

As previously known, patients with prolonged atrial fibrillation often have atrial thrombus. However, in children, cardiogenic embolism due to atrial fibrillation is rare. Also, the diagnosis of residual thrombus in the left atrial appendage is sometimes difficult even by transesophageal echocardiography (TEE). We have obtained a meaningful comparison between TEE findings and surgical specimen of bilateral atrial appendage.

Case report

A 12-year-old boy admitted to the nearby hospital, because of sudden onset of right-side hemiplegia. Till then, he was born at normal weight and grew up without any problem. The electrocardiogram indicated atrial fibrillation. He was transferred to the pediatric cardiology department of a hospital with higher function for the treatment of cardiogenic thromboembolism.

After 72 hours from the onset of first thromboembolism, a new embolic event happened in his left brachial artery. The contrast-enhanced computed tomography (CT) showed thrombus of bilateral atrium and coronary sinus. Consequently, residual thrombus led to the potential risk of additional embolization. Therefore, catheter cerebral thrombectomy was performed, and then surgical thrombectomy for the bilateral atrium was planned. Preoperative CT showed thrombus in the left atrial appendage (LAA). However, intraoperative TEE showed no obvious thrombus in the LAA. Intricate pectinate muscle formation in the left atrial appendage almost disappeared (figure1A), which suspected remaining thrombus. In addition, massive thrombus was seen in the right atrium and coronary sinus. Coronary sinus thrombus was removed as far as possible, and bilateral atrial appendage resection and myocardial biopsy were performed. Simultaneously, modified-Maze was also done. Heart rhythm returned into sinus rhythm after surgery. Pathological findings did not show specific findings of myocarditis or pericarditis.

Until now, the cause of thrombotic factors has not been fully clarified. Although the time of onset is unknown, probably, heart failure was triggered by atrial fibrillation, and consequently thromboembolism occurred. In the resected left atrial appendage, small thrombus remained among pectinate muscle (figure1B); therefore, postoperative anticoagulation should be needed.

Conclusion

We experienced a boy with thrombus in bilateral atrial appendages. In the resected left atrial appendage, multiple small thrombi remained in the pectinate muscle. From our experience, the disappearance of comb-like form in pectinate muscle by TEE suspects the residual thrombus, especially in the case of cardiogenic embolism.

Abstract P1472 Figure.

HIGH STEROL ESTER 1 is a key factor in plant sterol homeostasis

Plants strictly regulate the levels of sterol in their cells, as high sterol levels are toxic. However, how plants achieve sterol homeostasis is not fully understood. We isolated an Arabidopsis thaliana mutant that abundantly accumulated sterol esters in structures of about 1 µm in diameter in leaf cells. We designated the mutant high sterol ester 1 (hise1) and called the structures sterol ester bodies. Here, we show that HISE1, the gene product that is altered in this mutant, functions as a key factor in plant sterol homeostasis on the endoplasmic reticulum (ER) and participates in a fail-safe regulatory system comprising two processes. First, HISE1 downregulates the protein levels of the β-hydroxy β-methylglutaryl-CoA reductases HMGR1 and HMGR2, which are rate-limiting enzymes in the sterol synthesis pathway, resulting in suppression of sterol overproduction. Second, if the first process is not successful, excess sterols are converted to sterol esters by phospholipid sterol acyltransferase1 (PSAT1) on ER microdomains and then segregated in SE bodies.

P2693Late catch-up phenomenon and late-term target lesion revascularization of two-stenting for coronary bifurcation lesions between first and second generation drug-eluting stents

Background

The second generation drug-eluting stent (G2-DES) has been reported as superior to the first generation drug-eluting stent (G1-DES) in mid-term outcomes. However, the late-term outcomes between G1-DES and G2-DES in two-stenting for coronary bifurcation lesions are not well studied.

Purpose

To evaluate the late catch-up phenomenon and late-term target lesion revascularization (TLR) of two-stenting for coronary bifurcation lesions between G1-DES and G2-DES.

Methods

This study included 1133 lesions in 1089 patients undergoing drug eluting stent implantation with two stenting from 2004 to 2016. These consisted of 496 G1-DES implanted lesions and 637 G2-DES implanted lesions. Late-term follow-up angiography was performed without in-stent restenosis (ISR) and TLR at mid-term follow-up in 582 lesions (242 G1-DES lesions and 340 G2-DES lesions). ISR was defined as more than 50% restenosis. Late catch-up phenomenon was defined as ISR without ISR within 1 year following index stent implantation. Late-term TLR was defined as from 1 to 5 year TLR. Bifurcation lesions were defined as the main branch ranging from the proximal stem to the distal main branch with boundaries defined by 5 mm proximal and distal to the stent-implanted area, and the side branch ranging from the bifurcation carina to the distal side branch with boundaries defined by the carina and 5 mm distal to the stent-implanted area.

Results

The median follow-up duration was 5.1 years (the first and third quarters, 3.2 and 7.1 years). The late-catch up phenomenon rate significantly differed between the G1-DES and G2-DES groups (16.9% vs 8.4%, p=0.001). A significant difference in late catch-up between the same two groups was also observed in bifurcation lesions of the main branch (5.0% vs 0.6%, p=0.001) and side branch (10.3% vs 5.6%, p=0.033), respectively. The 5-year cumulative rates also differed between the two groups in TLR (8.2% vs 3.7% log-rank p=0.001), and late-term TLR (7.0% vs 3.6% log-rank p=0.001).

Conclusion

Two-stenting using G2-DES, compared with G1-DES, significantly reduced late-term restenosis and TLR. The restenosis rate in bifurcation area may be associated with differences between two groups in late-term outcome.

P5614The association between tissue morphology assessed with optical coherence tomography and mid and late-term results after percutaneous coronary intervention for in-stent restenosis lesions

Background

It was reported that tissue morphology of in-stent restenosis (ISR) lesions assessed with optical coherence tomography (OCT) had an effect on midterm results including ISR and target lesion revascularization (TLR) rates after percutaneous coronary intervention (PCI). However, little was known about the association between tissue morphology assessed with OCT and late-term results.

Methods

We performed PCI treated with paclitaxel coated balloon (PCB) or drug-eluting stent (DES) for 452 ISR lesions (260 lesions with fibrous plaque and 192 lesions with lipid-laden plaque) using OCT between May 2008 and July 2016. Six- to eight-month (midterm) angiographic follow-up was performed on 422 of the 452 ISR lesions (follow-up rate: 93.4%). Furthermore, eighteen- to twenty-month (late-term) angiographic follow-up was performed on 337 of the 361 ISR lesions (follow-up rate: 93.4%) which were free from midterm TLR. We examined the association between tissue morphology, midterm-results and late-term results including ISR and TLR rates. Fibrous plaque was defined as homogeneous, signal-rich regions with low attenuation. Lipid-laden plaque was defined as diffuse border, signal poor regions with high attenuation.

Results

The patients were 353 men and 69 women, and the mean age was 68.8±9.6 years. PCI were performed with PCB in 285 lesions (PCB group) and DES in 137 lesions (DES group). The figure shows the angiographic midterm results of the 422 lesions and late-term results of the 337 lesions with respect to each tissue morphology and each PCI device. There was no difference in ISR and TLR rates of lesions with both fibrous and lipid-laden plaque at midterm between the two groups. ISR and TLR rates of lesions with lipid-laden plaque at late-term were significantly higher in the PCB group than in the DES group, while there was no difference in ISR and TLR rates of lesions with fibrous plaque at late-term between two groups.

Figure 1

Conclusion

Tissue morphology of ISR lesions might have an impact on outcomes after PCI. Morphological assessment of ISR tissue using OCT might suggest favorable types of PCI for ISR lesions.

P1628Angiopoietin-like protein (Angptl) 2 secreted from epicardial adipose tissue induces atrial myocardial fibrosis

Background

Using excised human left atrial appendage samples, we previously demonstrated that epicardial adipose tissue (EAT) are highly associated with atrial myocardial fibrosis as a substrate of atrial fibrillation (AF). We also reported the relationship between Angptl2 in EAT and atrial fibrosis. However, the mechanism is not clear. The purpose is to clarify the mechanisms underlying the effect of EAT on the atrial myocardium.

Methods

Human peri-left atrial EAT and abdominal subcutaneous adipose tissue (SAT) samples were obtained from 6 cases (2 females, 70.2±13.2 years). 50 mg of EAT and SAT were quickly washed with PBS and centrifuged 1min at 1200rpm. After 3 times this procedures, adipose tissues were cultured in DMEM F12 medium with Fetal bovine Serum (FBS) overnight.

After pre-incubation, EAT and SAT tissues were washed and centrifuge d three times and cultured in medium without FBS for 24hours. Finally, we collected oozed medium (conditioned medium) and used for experiments.

Concentrations of Angptl2 in conditioned medium were measured by ELISA.

To study the effects of conditioned medium, we used “organo-culture” system. Isolated atrium from 8week old male Sprague-Dawley rats were placed on the porous membrane with the endothelial face toward the membrane. After that, loading medium (conditioned medium:culture medium = 1:4), culture medium (control), or recombinant Angptl2 were dropped onto the epicardial face of the atrium once a day and incubated for 7 days (37°C, 5% CO2).

Then, histological and immunohistochemical analysis were performed. We also performed quantitative reverse transcription–polymerase chain reaction (RT–PCR) analysis.

Next, we isolated and cultured neonatal rat fibroblast and loaded Angptl2 for 24 hours.After collected these cells, we performed western blotting analysis.

Results

Atria organo-culture incubated for 7 days with conditioned medium showed global fibrosis. At epicardial side, fibrotic area of EAT group was significantly greater compared to that of SAT and control group (P<0.05).

mRNA of Col1a1, col3a1 and TGFβ1 were significantly increased in EAT group compared with the SAT and control group.

And, the concentration of conditioned medium created from EAT was significant higher than that from SAT (P<0.05).

Then, we dropped 500 ng/ml of recombinant Angptl2 onto the rat atria. Fibrotic area of Angptl22 group significantly greater than that of control with increasing number of α-SMA positive cells, and mRNA of col3a1 and TGFβ1 were significantly increased in Angptl2 group compared with control group.

In cultured fibroblasts, α-SMA and p-ERK expression were increased in Angptl2 group measured by western blotting analysis.

Conclusions

Our results demonstrated that EAT rather than SAT induces atrial myocardial fibrosis. There is a possibility that Angptl2 effused from EAT plays a part in atrial fibrosis thought EAT paracrine effect.

Acknowledgement/Funding

ONO PHARMACEUTICAL CO

Identification of Periplasmic Root-Cap Mucilage in Developing Columella Cells of Arabidopsis thaliana

Plant roots secrete various substances with diverse functions against both plants and microbes in the rhizosphere. A major secretory substance is root-cap mucilage, whose functions have been well characterized, albeit mainly in crops. However, little is currently known about the developmental mechanisms of root-cap mucilage. Here, we show the accumulation and extrusion of root-cap mucilage in Arabidopsis. We found propidium iodide (PI) stainable structures between the plasma membrane and cell wall in the sixth layer of columella cells (c6) from the quiescent center. Ruthenium red staining and PI staining with calcium ions suggested that the structure comprises in part pectin polysaccharides. Electron microscopy revealed that the structure had a meshwork of electron-dense filaments that resembled periplasmic mucilage in other plants. In the c6 cells, we also observed many large vesicles with denser meshwork filaments to periplasmic mucilage, which likely mediate the transport of mucilage components. Extruded mucilage was observed outside a partially degraded cell wall in the c7 cells. Moreover, we found that the Class IIB NAC transcription factors BEARSKIN1 (BRN1) and BRN2, which are known to regulate the terminal differentiation of columella cells, were required for the efficient accumulation of root-cap mucilage in Arabidopsis. Taken together, our findings reveal the accumulation of and dynamic changes in periplasmic mucilage during columella cell development in Arabidopsis.

Biogenesis of leaf endoplasmic reticulum body is regulated by both jasmonate-dependent and independent pathways

Endoplasmic reticulum (ER) bodies are thought to function in plant defense against insects and pathogens. Recently, a new type of ER body referred to as "leaf ER bodies" (L-ER bodies) was identified in Arabidopsis rosette leaves. L-ER bodies accumulate two β-glucosidases, namely PYK10 and BGLU18, which are characteristic of previously described constitutive ER bodies and inducible ER bodies, respectively. However, it is unclear how the biogenesis of L-ER bodies, which are similar to both constitutive and inducible ER bodies, is regulated. In the present study, we show that the biogenesis of L-ER bodies is regulated by both jasmonate (JA)-dependent and -independent pathways. Confocal imaging analysis revealed the presence of L-ER bodies in the JA insensitive mutant coronatine insensitive 1-1 (coi1-1), which lacks the JA receptor COI1. Quantitative reverse transcription polymerase chain reaction analysis revealed that the expression of BGLU18 mainly depends on the JA signaling pathway while that of PYK10 does not. In addition, expression of the ER body related genes NAI1, NAI2, and TSA1 was reduced in the coi1-1 mutant relative to the wild type. Taken together, these findings suggest that JA signaling is not necessary for the formation of L-ER bodies, while it is partially required for gene expression of L-ER body components.

Leaf Endoplasmic Reticulum Bodies Identified in Arabidopsis Rosette Leaves Are Involved in Defense against Herbivory

ER bodies are endoplasmic reticulum (ER)-derived organelles specific to the order Brassicales and are thought to function in plant defense against insects and pathogens. ER bodies are generally classified into two types: constitutive ER bodies in the epidermal cells of seedlings, and wound-inducible ER bodies in rosette leaves. Herein, we reveal a third type of ER body found in Arabidopsis (Arabidopsis thaliana) rosette leaves and designate them "leaf ERbodies" (L-ER bodies). L-ER bodies constitutively occurred in specific cells of the rosette leaves: marginal cells, epidermal cells covering the midrib, and giant pavement cells. The distribution of L-ER bodies was closely associated with the expression profile of the basic helix-loop-helix transcription factor NAI1, which is responsible for constitutive ER-body formation. L-ER bodies were seldom observed in nai1 mutant leaves, indicating that NAI1 is involved in L-ER body formation. Confocal imaging analysis revealed that L-ER bodies accumulated two types of β-glucosidases: PYK10, the constitutive ER-body β-glucosidase; and BETA-GLUCOSIDASE18 (BGLU18), the wound-inducible ER-body β-glucosidase. Combined with the absence of L-ER bodies in the bglu18 pyk10 mutant, these results indicate that BGLU18 and PYK10 are the major components of L-ER bodies. A subsequent feeding assay with the terrestrial isopod Armadillidium vulgare revealed that bglu18 pyk10 leaves were severely damaged as a result of herbivory. In addition, the bglu18 pyk10 mutant was defective in the hydrolysis of 4-methoxyindol-3-ylmethyl glucosinolate These results suggest that L-ER bodies are involved in the production of defensive compound(s) from 4-methoxyindol-3-ylmethyl glucosinolate that protect Arabidopsis leaves against herbivory attack.

Polar Localization of the Borate Exporter BOR1 Requires AP2-Dependent Endocytosis

Boron (B) is an essential element in plants but is toxic when it accumulates to high levels. In root cells of Arabidopsis (Arabidopsis thaliana), the borate exporter BOR1 is polarly localized in the plasma membrane toward the stele side for directional transport of B. Upon high-B supply, BOR1 is rapidly internalized and degraded in the vacuole. The polar localization and B-induced vacuolar sorting of BOR1 are mediated by endocytosis from the plasma membrane. To dissect the endocytic pathways mediating the polar localization and vacuolar sorting, we investigated the contribution of the clathrin adaptor protein, ADAPTOR PROTEIN2 (AP2) complex, to BOR1 trafficking. In the mutants lacking µ- or σ-subunits of the AP2 complex, the polar localization and constitutive endocytosis of BOR1 under low-B conditions were dramatically disturbed. A coimmunoprecipitation assay showed association of the AP2 complex with BOR1, while it was independent of YxxΦ sorting motifs, which are in a cytosolic loop of BOR1. A yeast two-hybrid assay supported the interaction of the AP2 complex µ-subunit with the C-terminal tail but not with the YxxΦ motifs in the cytosolic loop of BOR1. Intriguingly, lack of the AP2 subunit did not affect the B-induced rapid internalization/vacuolar sorting of BOR1. Consistent with defects in the polar localization, the AP2 complex mutants showed hypersensitivity to B deficiency. Our results indicate that AP2-dependent endocytosis maintains the polar localization of BOR1 to support plant growth under low-B conditions, whereas the B-induced vacuolar sorting of BOR1 is mediated through an AP2-independent endocytic pathway.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

A Case of Feline T-cell Lymphoma with Tropism for Striated Muscle and Peripheral Nerve

An 11-year-old female American shorthair cat was presented with a 3-month history of hindlimb ataxia and knuckling of the left forelimb. Clinical abnormalities included weight loss, hyperaesthesia of the neck and back, cardiac murmur and systemic muscle atrophy. The cat died 10 days after the initial presentation and a necropsy examination was performed. Grossly, extensive pale lesions were seen in the wall of the left ventricle and the septum of the heart. There were no detectable masses in the heart, skeletal muscles or peripheral nerves. Histopathological examination revealed diffuse, extensive infiltration of atypical lymphoid cells in the heart; the cardiac muscles were markedly degenerate and atrophic and were replaced by the neoplastic cells. Neoplastic cells with similar morphology were seen in all specimens of the skeletal muscles and peripheral nerves. Clonality analysis of the paraffin wax-embedded heart tissue revealed a monoclonal rearrangement of the gene encoding the T-cell receptor γ chain. Based on these findings, the case was diagnosed as T-cell lymphoma with tropism for striated muscle and peripheral nerve.

The AP-1 Complex is Required for Proper Mucilage Formation in Arabidopsis Seeds

The adaptor protein (AP) complexes play crucial roles in vesicle formation in post-Golgi trafficking. Land plants have five types of AP complexes (AP-1 to AP-5), each of which consists of two large subunits, one medium subunit and one small subunit. Here, we show that the Arabidopsis AP-1 complex mediates the polarized secretion and accumulation of a pectic polysaccharide called mucilage in seed coat cells. Previously, a loss-of-function mutant of AP1M2, the medium subunit of AP-1, has been shown to display deleterious growth defects because of defective cytokinesis. To investigate the function of AP-1 in interphase, we generated transgenic Arabidopsis plants expressing AP1M2-GFP (green fluorescent protein) under the control of the cytokinesis-specific KNOLLE (KN) promoter in the ap1m2 background. These transgenic plants, designated pKN lines, successfully rescued the cytokinesis defect and dwarf phenotype of ap1m2. pKN lines showed reduced mucilage extrusion from the seed coat. Furthermore, abnormal accumulation of mucilage was found in the vacuoles of the outermost integument cells of pKN lines. During seed development, the accumulation of AP1M2-GFP was greatly reduced in the integument cells of pKN lines. These results suggest that trans-Golgi network (TGN)-localized AP-1 is involved in the trafficking of mucilage components to the outer surface of seed coat cells. Our study highlights an evolutionarily conserved function of AP-1 in polarized sorting in eukaryotic cells.

Efficient CRISPR/Cas9-based genome editing and its application to conditional genetic analysis in Marchantia polymorpha

Marchantia polymorpha is one of the model species of basal land plants. Although CRISPR/Cas9-based genome editing has already been demonstrated for this plant, the efficiency was too low to apply to functional analysis. In this study, we show the establishment of CRISPR/Cas9 genome editing vectors with high efficiency for both construction and genome editing. Codon optimization of Cas9 to Arabidopsis achieved over 70% genome editing efficiency at two loci tested. Systematic assessment revealed that guide sequences of 17 nt or shorter dramatically decreased this efficiency. We also demonstrated that a combinatorial use of this system and a floxed complementation construct enabled conditional analysis of a nearly essential gene. This study reports that simple, rapid, and efficient genome editing is feasible with the series of developed vectors.

Synaptotagmin-Associated Endoplasmic Reticulum-Plasma Membrane Contact Sites Are Localized to Immobile ER Tubules

The plant endoplasmic reticulum (ER), which is morphologically divided into tubules and sheets, seems to flow continuously as a whole, but locally, mobile and immobile regions exist. In eukaryotes, the ER physically and functionally interacts with the plasma membrane (PM) at domains called ER-PM contact sites (EPCSs). Extended synaptotagmin family proteins are concentrated in the cortical ER to form one type of EPCS; however, it is unclear whether the localization of extended synaptotagmin corresponds to the EPCS and where in the cortical ER the EPCSs are formed. Here, we analyzed the spatiotemporal localization of SYNAPTOTAGMIN1 (SYT1), a synaptotagmin in Arabidopsis (Arabidopsis thaliana), to investigate the precise distribution of SYT1-associated EPCSs in the cortical ER. Three-dimensional imaging using superresolution confocal live imaging microscopy demonstrated that SYT1 was specifically localized to the ER-PM boundary. Time-lapse imaging revealed that SYT1 was distributed to immobile ER tubules, but not to mobile tubules. Moreover, SYT1 was frequently localized to the edges of ER sheets that were transformed into immobile ER tubules over time. A lower intracellular calcium ion concentration resulted in an increased EPCS area and disrupted the ER network. Finally, SYT1 deficiency caused a reduction of the immobile tubules and enlargement of the ER meshes. Taken together, our findings show that SYT1-associated EPCS are distributed to immobile tubules and play an important role in the formation of the tubular ER network. This provides important insight into the relationship between the function and dynamics/morphology of the cortical ER.

Endoplasmic Reticulum (ER) Membrane Proteins (LUNAPARKs) are Required for Proper Configuration of the Cortical ER Network in Plant Cells

The endoplasmic reticulum (ER) is a large network made of membranous cisternae and tubules, which accounts for a large proportion of the total lipid bilayer endomembrane of the cell. In mammals and yeast, LUNAPARK proteins are preferentially localized at the three-way junctions of the ER network, stabilizing the junctions and establishing the ER architecture. We identified two Arabidopsis homologs and designated them LNPA and LNPB. Subcellular localization analysis with a non-dimerizable type of green fluorescent protein (GFP) revealed that both LNPA and LNPB are predominantly distributed throughout the ER, but not preferentially localized at the three-way junctions. Quantitative analysis of the network in the double mutant lnpa lnpb revealed that deficiency of LNPA and LNPB caused the cortical ER to develop poor ER cisternae and a less dense tubular network. These phenotypes are opposite to those of LNP-deficient mutants of yeast and mammals. Despite the importance of cysteine residues in the zinc finger motif of the yeast LNP homolog (Lnp1p), the corresponding cysteine residues of LNPA were not necessary for the stabilization of ER morphology because replacing the four cysteine residues in the zinc finger motif of the LNPA protein with alanine residues did not affect its function. A significant phenotype of lnpa lnpb is generation of large spherical structures from the ER. Formation of the structures might reduce the amounts of the ER membrane to be used for generating the network, resulting in poor development of the ER network. Taken together, our results suggest that plant LNPs function differently from those in yeast and mammals: they function to distribute ER membranes appropriately throughout the cells.

Plant Vacuoles

Plant vacuoles are multifunctional organelles. On the one hand, most vegetative tissues develop lytic vacuoles that have a role in degradation. On the other hand, seed cells have two types of storage vacuoles: protein storage vacuoles (PSVs) in endosperm and embryonic cells and metabolite storage vacuoles in seed coats. Vacuolar proteins and metabolites are synthesized on the endoplasmic reticulum and then transported to the vacuoles via Golgi-dependent and Golgi-independent pathways. Proprotein precursors delivered to the vacuoles are converted into their respective mature forms by vacuolar processing enzyme, which also regulates various kinds of programmed cell death in plants. We summarize two types of vacuolar membrane dynamics that occur during defense responses: vacuolar membrane collapse to attack viral pathogens and fusion of vacuolar and plasma membranes to attack bacterial pathogens. We also describe the chemical defense against herbivores brought about by the presence of PSVs in the idioblast myrosin cell.

Involvement of Adapter Protein Complex 4 in Hypersensitive Cell Death Induced by Avirulent Bacteria

Plant immunity to avirulent bacterial pathogens is associated with subcellular membrane dynamics including fusion between the vacuolar and plasma membranes, resulting in hypersensitive cell death. Here, we report that ADAPTOR PROTEIN COMPLEX-4 (AP-4) subunits are involved in plant immunity associated with hypersensitive cell death. We isolated a mutant with a defect in resistance to an avirulent strain of Pseudomonas syringae pv. tomato (Pto) DC3000 avrRpm1 from a vacuolar protein sorting mutant library of Arabidopsis (Arabidopsis thaliana). The mutant was identical to gfs4-1, which has a mutation in the gene encoding the AP-4 subunit AP4B. Thus, we focused on AP4B and another subunit, AP4E. All of the mutants (ap4b-3, ap4b-4, ap4e-1, and ap4e-2) were defective in hypersensitive cell death and resistance to Pto DC3000 with the type III effector AvrRpm1 or AvrRpt2, both of which are recognized on the plasma membrane, while they showed slightly enhanced susceptibility to the type-III-secretion-deficient P. syringae strain hrcC On the other hand, both ap4b-3 and ap4b-4 showed no defect in resistance to Pto DC3000 with the type III effector AvrRps4, which is recognized in the cytosol and does not induce hypersensitive cell death. Upon infection with Pto DC3000 avrRpt2, the ap4b-3 and ap4b-4 leaf cells did not show fusion between vacuolar and plasma membranes, whereas the wild-type leaf cells did. These results suggest that AP-4 contributes to cell death-associated immunity, possibly via membrane fusion, after type III effector-recognition on the plasma membrane.

Subcellular localisation of an endoplasmic reticulum-plasma membrane tethering factor, SYNAPTOTAGMIN 1, is affected by fluorescent protein fusion

Membrane contact sites (MCS) have increasingly received attention because of their general role in a number of important cellular processes. SYNAPTOTAGMIN 1 (SYT1) is a tethering factor connecting the endoplasmic reticulum (ER) and the plasma membrane (PM) in plant cells. Confocal microscopy using fluorescent protein fusion is an indispensable tool for studying protein localisation and functions. However, several studies have reported that fluorescent protein dimerisation affects the subcellular localisation of proteins tagged by the fluorescent protein. Here, we investigate the effects of fluorescent protein dimerisation by comparing the subcellular localisation of SYT1 fused with a synthetic GFP (SYT1-sGFP) and SYT1 fused with a monomeric GFP (SYT1-mGFP). SYT1-mGFP was confined to specific domains in the ER, whereas SYT1-sGFP spread along the ER when transiently overexpressed. SYT1-localised regions were suggested to correspond to ER-PM contact sites because of its immobility. Similar results were obtained in the transgenic Arabidopsis, even though SYT1-sGFP and SYT1-mGFP were expressed at comparable levels. It is suggested that SYT1-mGFP more accurately reproduced SYT1 localisation in intact cells because the proportion of persistent area in the ER was more similar between the wild type and the plant expressing SYT1-mGFP than between the wild type and the plant expressing SYT1-sGFP. Taken together, these results suggest that the fusion of sGFP makes SYT1-sGFP form excessive ER-PM contact sites in the ER.