A comparative analysis of attitudes toward genome-edited food among Japanese public and scientific community

Genome editing technologies such as CRISPR/Cas9 have been developed in the last decade and have been applied to new food technologies. Genome-edited food (GEF) is a crucial issue with those new food technologies. Thus, each country has established GEF governance systems to maximize benefits and minimize risks. These emphasize the importance of communicating about GEF to the public. The key concerns are understanding various viewpoints and value perspectives (framings) in science and technology and encouraging and opening communication with the public. Thus, it is essential to understand differences between the public and experts' interests and discuss various framings and effective communication with regard to GEF. Accordingly, this study involved administering a questionnaire to analyze the public's attitudes in Japan and identify gaps between these and expert opinions on GEF. A total of 4000 responses from the public and 398 responses from GEF experts were collected. The study found that the Japanese public has a "wait-and-watch" attitude toward GEF, and the demand for basic information on it is quite high. Moreover, they are apprehensive about proper risk governance systems for GEF. This is despite experts' emphasis on the adequacy of the mechanism, necessity of technology, and trust in the scientific community. Understanding gaps between the public and experts' opinions on and interests in GEF provides essential insight for effective communication and acts as the basis for appropriate governance of emerging science and technology.

Short-term decreased post transplant lymphoproliferative disorder risk after kidney transplantation using two novel regimens

BACKGROUND

Belatacept is employed alongside calcineurin inhibitor (CNI) therapy to prevent graft rejection in kidney transplant patients who are Epstein-Barr virus (EBV) seropositive. Preliminary data suggested that rates of post-transplant lymphoproliferative disorder (PTLD) were higher in individuals treated with belatacept compared to CNI therapy alone.

METHODS

The records of 354 adults who underwent kidney only transplantation from January 2015 through September 2021 at one medical center were evaluated. Patients underwent treatment with either low-doses of mycophenolate, tacrolimus and sirolimus (B⁰, n = 235) or low-doses of mycophenolate, tacrolimus and belatacept (B¹, n = 119). All recipients underwent induction with antithymocyte globulin and a rapid glucocorticosteroid taper. Relevant donor and recipient information were analyzed and endpoints of PTLD were assessed.

RESULTS

There were no cases of PTLD in either cohort within the study period. Recipients in the belatacept cohort experienced lower estimated glomerular filtration rates at 12 months (B⁰: 67.48 vs. B¹: 59.10, p = 0.0014). Graft failure at 12 (B⁰: 1.28% vs. B¹: 0.84%, p = 1.0) and 24 months (B⁰:2.55% vs. B¹: 0.84%, p = 0.431) were similar. There was no difference in rejection rates at 12 (B⁰: 1.27% vs. B¹: 2.52%, p = 0.408) or 24 months (B⁰: 2.12% vs. B¹: 2.52%, p = 1.000). Both groups had similar rates of malignancy, mortality and CMV/BK viremia.

CONCLUSION

Non-belatacept (MMF, tacrolimus and sirolimus) and belatacept-based (MMF, tacrolimus and belatacept) regimens do not appear to pose any increased risk of early onset PTLD. Both cohorts benefited from low rates of rejection, malignancy, mortality and graft failure. Recipients will continue to be monitored as PTLD can manifest as a long-term complication.

IRE1-mediated cytoplasmic splicing and regulated IRE1-dependent decay of mRNA in the liverwort Marchantia polymorpha

The unfolded protein response (UPR) or the endoplasmic reticulum (ER) stress response is a homeostatic cellular response conserved in eukaryotes to alleviate the accumulation of unfolded proteins in the ER. In the present study, we characterized the UPR in the liverwort Marchantia polymorpha to obtain insights into the conservation and divergence of the UPR in the land plants. We demonstrate that the most conserved UPR transducer in eukaryotes, IRE1, is conserved in M. polymorpha, which harbors a single gene encoding IRE1. We showed that MpIRE1 mediates cytoplasmic splicing of mRNA encoding MpbZIP7, a M. polymorpha homolog of bZIP60 in flowering plants, and upregulation of ER chaperone genes in response to the ER stress inducer tunicamycin. We further showed that MpIRE1 also mediates downregulation of genes encoding secretory and membrane proteins in response to ER stress, indicating the conservation of regulated IRE1-dependent decay of mRNA. Consistent with their roles in the UPR, Mpire1 ^ge and Mpbzip7 ^ge mutants exhibited higher sensitivity to ER stress. Furthermore, an Mpire1 ^ge mutant also exhibited retarded growth even without ER stress inducers, indicating the importance of MpIRE1 for vegetative growth in addition to alleviation of ER stress. The present study provides insights into the evolution of the UPR in land plants.

THESEUS1 is involved in tunicamycin-induced root growth inhibition, ectopic lignin deposition, and cell wall damage-induced unfolded protein response

Endoplasmic reticulum (ER) stress activates unfolded protein responses (UPRs), such as promoting protein folding under the control of specific gene expression. Our previous study showed that ER stress induced by ER stress inducers such as tunicamycin (Tm), an inhibitor of N-linked glycan synthesis, causes ectopic lignin deposition in Arabidopsis roots, but the relationship between UPR and ectopic lignin deposition remains unclear. The receptor-like kinase THESEUS1 (THE1) has been shown to sense cell wall damage (CWD) induced in Arabidopsis by cellulose synthase inhibitors such as isoxaben (ISO) and to activate ectopic lignin deposition. In this study, we assessed the involvement of THE1 in ectopic lignin deposition caused by the ER stress inducer Tm. The loss-of-function mutation of THE1, the1-3, suppressed Tm-induced root growth inhibition and ectopic lignin deposition, revealing that THE1 is involved in root growth defects and ectopic lignin deposition caused by ER stress. Similarly, ISO treatment induced ectopic lignin deposition as well as the expression of the UPR marker genes binding protein 3 (BiP3) and ER-localized DnaJ 3b (ERdj3b). Conversely, in the the1-3 mutant, ISO-induced ectopic lignin deposition and the expression of BiP3 and ERdj3b were suppressed. These results showed that THE1 is involved in not only root growth inhibition and ectopic lignin deposition caused by ER stress but also CWD-induced UPR.

Unpaired nucleotides on the stem of microRNA precursor are important for precise cleavage by Dicer-Like1 in Arabidopsis

Dicer-Like1 (DCL1) is a core component of the plant microRNA (miRNA) biogenesis machinery. MiRNA is transcribed as a precursor RNA, termed primary miRNA (pri-miRNA), which is cleaved by DCL1 in two steps to generate miRNA/miRNA* duplex. Pri-miRNA is a single-stranded RNA that forms a hairpin structure with a number of unpaired bases, hereafter called mismatches, on its stem. In the present study, by using purified recombinant Arabidopsis DCL1, we presented evidence that mismatches on the stem of pri-miRNA are important for precise DCL1 cleavage. We showed that a mismatch at the loop-distal side of the end of miRNA/miRNA* duplex is important for efficient cleavage of pri-miRNA in vitro, as previously suggested in planta. On the other hand, mismatches distant from the miRNA/miRNA* duplex region are important for determining the cleavage position by DCL1. The purified DCL1 proteins cleaved mutant pri-miRNA variants without such mismatches at a position at which wild-type pri-miRNA variants are not usually cleaved, resulting in an increased accumulation of small RNA different from miRNA. Therefore, our results suggest that, in addition to the distance from the ssRNA-dsRNA junction, mismatches on the stem of pri-miRNA function as a determinant for precise processing of pri-miRNA by DCL1 in plants.

Kidney transplant surgical director training: Urologists represent a functional alternative to general surgeons

INTRODUCTION

Kidney transplant (KT) directors are general surgeons or urologists. All KT centers must meet established performance standards. However, it has not been established if general surgery and urology led programs have disparate outcomes.

METHODS

Transplant outcomes and donor-recipient characteristics by director training were investigated. Organ Procurement and Transplantation Network (OPTN) directory, program websites were analyzed for surgical director demographics. Scientific Registry of Transplant Recipients (SRTR) 1-year kidney survival and deceased donor (DD) wait-time rankings were evaluated. A retrospective analysis of 142 157 KT recipients from 2010 to 2019 was performed using the United Network for Organ Sharing (UNOS) database.

RESULTS

One hunderd and seventy three (90.6%) KT programs were led by general surgeons. There were no significant differences in gender, ethnicity, region, credentials, or fellowship completion. Recipients undergoing KT with urology led programs were older (P = .002) and had longer wait-times (P < .001). These centers used higher KDPI (.47 vs. .45, P < .001) and higher HLA mismatch (3.92 vs. 3.89, P = .02) kidneys. Urology led centers utilized living donors less frequently (32.1% vs. 35.8%, P < .001) and had longer CIT (15.44 vs. 12.21, P < .001). Both had similar SRTR ranking of 1-year survival and DD wait-time.

CONCLUSION

Most directors were general surgeon. Patient outcomes did not differ by transplant director training. Urologists represent a viable option for KT leadership and recruitment should be encouraged.

Correlation between alterations in blood flow of malignant lymphomas after induction chemotherapies and clinical outcomes: a pilot study utilising contrast-enhanced ultrasonography for early interim evaluation of lymphoma treatment

AIM

To clarify the utility of contrast-enhanced ultrasonography (CEUS) for interim evaluation of response to chemotherapy in lymphoma treatment.

MATERIALS AND METHODS

CEUS was performed both before (day 0) and after the treatment (7 and/or 14 days), and a time-intensity curve was obtained. The patients were divided into two groups (complete remission [CR] group and non-CR group) according to the results of conventional response evaluation, and peak enhancement (PE), time to peak enhancement, perfusion index (PI), the total area under the curve during wash-in (AUC-in), and the total AUC were compared between the groups.

RESULTS

Among 27 patients with various types of lymphoma, the median change ratio of PE and PI at day 7 evaluation were significantly different between the CR group and the non-CR group (0.81 versus 1.39, p=0.017 for PE and 0.92 versus 2.09, p=0.010 for PI). The change ratio of PE < 1.09 (specificity: 86%; sensitivity, 88%) and PI < 1.65 (specificity: 86%; sensitivity: 94%) distinguished CR from non-CR. Patients who achieved a PE change ratio <1.09 or a PI change ratio <1.65 had significantly better estimated progression-free survival (p<0.001).

CONCLUSION

The present study demonstrated that changes in tumour perfusion parameters evaluated with CEUS at 1 week after the treatment initiation were significantly different between lymphoma patients in CR group and non-CR group. Alterations in perfusion parameters evaluated via CEUS could impact the prognosis of lymphoma patients.

Genetic engineering of eggplant accumulating β-carotene in fruit

Genetic engineering of eggplant using fruit-specific EEF48 promoter-driven bacterial PSY gene, crtB, confers β-carotene accumulation in fruit. Eggplant (Solanum melongena L.) is globally cultivated especially in Asia and is an important source of nutrients in the diets of low-income consumers in developing countries. Since fruits of eggplant have low provitamin A carotenoid content, it is expected to develop eggplant with high carotenoid content for combatting vitamin A deficiency. To achieve this, the present study implemented a metabolic engineering strategy to modify the carotenoid biosynthetic pathway in eggplant. Expression analysis of carotenogenic genes in eggplant tissues showed that the expression of the endogenous phytoene synthase (PSY) was low in fruit and callus. Orange-colored calluses were generated from ectopic expression of crtB gene, which encodes bacterial PSY, in eggplant cells. The orange calluses accumulated > 20 μg g^-1 FW of β-carotene, which was approximately 150-fold higher than that of the untransformed calluses. These observations suggest that the PSY expression is the rate-limiting step for β-carotene production in callus and fruit. Since the orange calluses did not regenerate plants, we chose eggplant EEF48 gene, which is presumably expressed in fruit. We amplified its promoter region by TAIL-PCR and showed that the EEF48 promoter is indeed active in eggplant fruit. Subsequently, transgenic eggplant lines having EEF48 promoter-driven crtB were produced. Among the transgenic lines produced, one line set fruit containing 1.50 μg g^-1 FW of β-carotene, which was 30-fold higher than that of the untransformed fruits (0.05 μg g^-1 FW). The self-pollinated progenies showed a 3:1 segregation ratio for the presence and absence of the transgene, which was linked to the β-carotene accumulation in fruit. These results provide a strategy for improvement of carotenoid content in eggplant fruit.

Unfolded protein-independent IRE1 activation contributes to multifaceted developmental processes in Arabidopsis

The Arabidopsis unfolded protein response transducer IRE1 contributes to male gametophyte development using an alternative activation mechanism bypassing the unfolded protein-sensing domain.

In Arabidopsis, the IRE1A and IRE1B double mutant (ire1a/b) is unable to activate cytoplasmic splicing of bZIP60 mRNA and regulated IRE1-dependent decay under ER stress, whereas the mutant does not exhibit severe developmental defects under normal conditions. In this study, we focused on the Arabidopsis IRE1C gene, whose product lacks a sensor domain. We found that the ire1a/b/c triple mutant is lethal, and heterozygous IRE1C (ire1c/+) mutation in the ire1a/b mutants resulted in growth defects and reduction of the number of pollen grains. Genetic analysis revealed that IRE1C is required for male gametophyte development in the ire1a/b mutant background. Expression of a mutant form of IRE1B that lacks the luminal sensor domain (ΔLD) complemented a developmental defect in the male gametophyte in ire1a/b/c haplotype. In vivo, the ΔLD protein was activated by glycerol treatment that increases the composition of saturated lipid and was able to activate regulated IRE1-dependent decay but not bZIP60 splicing. These observations suggest that IRE1 contributes to plant development, especially male gametogenesis, using an alternative activation mechanism that bypasses the unfolded protein-sensing luminal domain.

Deficiency in the double-stranded RNA binding protein HYPONASTIC LEAVES1 increases sensitivity to the endoplasmic reticulum stress inducer tunicamycin in Arabidopsis

Objective

microRNA (miRNA) is a small non-coding RNA that regulates gene expression by sequence-dependent binding to protein-coding mRNA in eukaryotic cells. In plants, miRNA plays important roles in a plethora of physiological processes, including abiotic and biotic stress responses. The present study was conducted to investigate whether miRNA-mediated regulation is important for the endoplasmic reticulum (ER) stress response in Arabidopsis.

Results

We found that hyl1 mutant plants are more sensitive to tunicamycin, an inhibitor of N-linked glycosylation that causes ER stress than wild-type plants. Other miRNA-related mutants, se and ago1, exhibited similar sensitivity to the wild-type, indicating that the hypersensitive phenotype is attributable to the loss-of-function of HYL1, rather than deficiency in general miRNA biogenesis and function. However, the transcriptional response of select ER stress-responsive genes in hyl1 mutant plants was indistinguishable from that of wild-type plants, suggesting that the loss-of-function of HYL1 does not affect the ER stress signaling pathways.

CRISPR/Cas9-mediated homologous recombination in tobacco

KEY MESSAGE

Co-transformation of multiple T-DNA in a binary vector enabled CRISPR/Cas9-mediated HR in tobacco. HR occurred in a limited region around the gRNA target site. In this study, CRISPR/Cas9-mediated homologous recombination (HR) in tobacco (Nicotiana tabacum L. 'SR-1') was achieved using binary vectors comprising two (T1-T2) or three (T1-T2-T3) independent T-DNA regions. For HR donor with the tobacco acetolactate synthase gene, SuRB, T-DNA1 contained ΔSuRBW568L, which lacked the N-terminus region of SuRB and was created by three nucleotide substitutions (ATG to GCT; W568L), leading to herbicide chlorsulfuron (Cs) resistance, flanked by the hygromycin (Hm)-resistant gene. T-DNA2 consisted of the hSpCas9 gene and two gRNA inserts targeting SuRB and An2. For the 2nd HR donor with the tobacco An2 gene encoding a MYB transcription factor involved in anthocyanin biosynthesis, T-DNA3 had a 35S promoter-driven An2 gene lacking the 3rd exon resulting in anthocyanin accumulation after successful HR. After selecting for Hm and Cs resistance from among the 7462 Agrobacterium-inoculated explants, 77 independent lines were obtained. Among them, the ATG to GCT substitution of endogenous SuRB was detected in eight T1-T2-derived lines and two T1-T2-T3-derived lines. Of these mutations, four T1-T2-derived lines were bi-allelic. All the HR events occurred across the endogenous SuRB and 5' homology arm of the randomly integrated T-DNA1. HR of the SuRB paralog, SuRA, was also found in one of the T1-T2-derived lines. Sequence analysis of its SuRA-targeted region indicated that the HR occurred in a limited (< 153 bp) region around the gRNA target site. Even though some T1-T2-T3-derived lines introduced three different T-DNAs and modified the An2 gRNA target site, no signs of HR in the endogenous An2 could be observed.

Isolation and characterization of Leptospira interrogans from two patients with leptospirosis in Western Province, Sri Lanka

Leptospirosis is an endemic infectious disease causing considerable morbidity and mortality in Sri Lanka; however, reports on the isolation of Leptospira from infected patients in Sri Lanka have been largely unavailable since the 1970s. Two isolates were obtained and characterized from 100 blood cultures from leptospirosis-suspected patients. Phylogenic analysis of partial flaB gene sequences identified the isolates as Leptospira interrogans. The patient serum samples from which Leptospira was isolated reacted with the Leptospira serogroups Sejroe and Canicola at a titre of 1 : 200. Exposure to domestic sewage and gutters filled with muddy water was suspected to be the source of infection in these two culture-positive patients. This study reports the successful isolation of pathogenic Leptospira from two patients in Western Province, Sri Lanka.

Interplay between the unfolded protein response and reactive oxygen species: a dynamic duo

Secretory proteins undergo modifications such as glycosylation and disulphide bond formation before proper folding, and move to their final destination via the endomembrane system. Accumulation of unfolded proteins in the endoplasmic reticulum (ER) due to suboptimal environmental conditions triggers a response called the unfolded protein response (UPR), which induces a set of genes that elevate protein folding capacity in the ER. This review aims to establish a connection among ER stress, UPR, and reactive oxygen species (ROS), which remains an unexplored topic in plants. For this, we focused on mechanisms of ROS production originating from ER stress, the interaction between ER stress and overall ROS signalling process in the cell, and the interaction of ER stress with other organellar ROS signalling pathways such as of the mitochondria and chloroplasts. The roles of the UPR during plant hormone signalling and abiotic and biotic stress responses are also discussed in connection with redox and ROS signalling.

Constitutive BiP protein accumulation in Arabidopsis mutants defective in a gene encoding chloroplast-resident stearoyl-acyl carrier protein desaturase

The unfolded protein response (UPR) occurs when protein folding and maturation are disturbed in the endoplasmic reticulum (ER). During the UPR, a number of genes including those encoding ER-resident molecular chaperones are induced. In Arabidopsis, BiP3 has been used as a UPR marker gene whose expression is strongly induced in response to ER stress. In this study, we mutagenized Arabidopsis plants expressing β-glucuronidase (GUS) gene under the control of BiP3 promoter and isolated a mutant that exhibits strong GUS activity without treatment with ER stress inducers. By whole genome sequencing, we identified a causal gene in the mutant as SUPPRESSOR OF SALICYLIC ACID INSENSITIVITY2 (SSI2), which encodes stearoyl-acyl carrier protein desaturase that converts stearic acids to oleic acids in the chloroplasts. In addition to GUS proteins, the ssi2 mutant accumulates endogenous BiP3 proteins without treatment by any stress reagents. Interestingly, although the degree of endogenous BiP3 protein accumulation in the ssi2 mutant was comparable to that in wild-type plants treated with the ER stress inducer tunicamycin, much less BiP3 transcripts were detected in the ssi2 mutant compared to tunicamycin-treated wild-type plants. Our finding suggests a genetic link between fatty acid metabolism in the chloroplasts and ER functions.

Activation of the Arabidopsis membrane-bound transcription factor bZIP28 is mediated by site-2 protease, but not site-1 protease

The unfolded protein response (UPR) is a homeostatic cellular response conserved in eukaryotic cells to alleviate the accumulation of unfolded proteins in the endoplasmic reticulum (ER). Arabidopsis bZIP28 is a membrane-bound transcription factor activated by proteolytic cleavage in response to ER stress, thereby releasing its cytosolic portion containing the bZIP domain from the membrane to translocate into the nucleus where it induces the transcription of genes encoding ER-resident molecular chaperones and folding enzymes. It has been widely recognized that the proteolytic activation of bZIP28 is mediated by the sequential cleavage of site-1 protease (S1P) and site-2 protease (S2P). In the present study we provide evidence that bZIP28 protein is cleaved by S2P, but not by S1P. We demonstrated that wild-type and s1p mutant plants produce the active, nuclear form of bZIP28 in response to the ER stress inducer tunicamycin. In contrast, tunicamycin-treated s2p mutants do not accumulate the active, nuclear form of bZIP28. Consistent with these observations, s2p mutants, but not s1p mutants, exhibited a defective transcriptional response of ER stress-responsive genes and significantly higher sensitivity to tunicamycin. Interestingly, s2p mutants accumulate two membrane-bound bZIP28 fragments with a shorter ER lumen-facing C-terminal domain. Importantly, the predicted cleavage sites are located far from the canonical S1P recognition motif previously described. We propose that ER stress-induced proteolytic activation of bZIP28 is mediated by the sequential actions of as-yet-unidentified protease(s) and S2P, and does not require S1P.

A 64-bp sequence containing the GAAGA motif is essential for CaMV-35S promoter methylation in gentian

This study investigated sequence specificity and perenniality of DNA methylation in the cauliflower mosaic virus (CaMV) 35S promoter of transgenic gentian (Gentiana triflora×G. scabra) plants. Unlike conventional transgene silencing models, 35S promoter hypermethylation in gentian is species-specific and occurs irrespective of the T-DNA copy number and genomic location. Modified 35S promoters were introduced into gentian, and single-copy transgenic lines were selected for methylation analysis. Modified 35S promoter lacking a core (-90) region [35S(Δcore)] in gentian conferred hypermethylation and high levels of de novo methylation of the CpHpH/CpCpG sites in the 35S enhancer regions (-298 to -241 and -148 to -85). Therefore, promoter transcription may not be an absolute requirement for the methylation machinery. In vitro, de novo methylation persisted for more than eight years. In another modified 35S promoter, two "GAAGA" motifs (-268 to -264 and -135 to -131) were replaced by "GTTCA" in the two highly de novo methylated regions. It did not support hypermethylation and showed transgene expression. A 64-bp fragment of the 35S enhancer region (-148 to -85) was introduced into gentian and the resultant transgenic lines analyzed. The 64-bp region exhibited hypermethylation at the CpG/CpWpG sites, but the CpHpH/CpCpG methylation frequency was lower than those of the unmodified 35S- and 35S(Δcore) promoters. Nevertheless, a distinct CpHpH/CpCpG methylation peak was found in the 64-bp region of all single-copy transgenic lines. These results suggest that the 64-bp region may contain an element required for 35S methylation but insufficient for high de novo methylation compared with those in the unmodified 35S and 35S(Δcore) promoters.

Overexpression of the endoplasmic reticulum stress-inducible gene TIN1 causes abnormal pollen surface morphology in Arabidopsis

The unfolded protein response (UPR) or the endoplasmic reticulum (ER) stress response occurs when folding and maturation of secretory and membrane proteins are impaired in the ER. The UPR induces a number of genes that encode ER-localized molecular chaperones and folding enzymes to increase folding capacity in the ER. We have identified Tunicamycin Induced 1 (TIN1), an Arabidopsis gene that is highly induced during the UPR. We have shown that TIN1 protein is localized in the ER but its physiological function remains to be elucidated. In the present study we generated and analyzed transgenic Arabidopsis plants expressing TIN1 under CaMV35S promoter to obtain insights into the physiological role of TIN1. We found that although TIN1-overexpressing plants grew as did wild-type plants under ambient laboratory conditions, their pollen grains exhibited abnormal surface morphology. The result suggests a specific role of TIN1 in secretion of proteins and/or lipids during pollen development.

Inositol-requiring enzyme 1 affects meristematic division in roots under moderate salt stress in Arabidopsis

The unfolded protein response (UPR) mitigates stress caused by accumulation of unfolded proteins in the endoplasmic reticulum (ER). Inositol-requiring enzyme 1 (IRE1) is the most conserved sensor of the UPR with ribonuclease activity that mediates cytoplasmic splicing and decay of mRNA encoding secretory and membrane proteins. In the present study, we demonstrate that the Arabidopsis mutant defective in two IRE1 genes exhibit retarded growth of primary roots under moderate salt stress, although such grow retardation is not observed in wild type plants. Microscopic observation showed decrease in the number of meristematic cells in the mutant under salt stress. This finding suggests that IRE1 plays a role in the maintenance of root meristems under salt stress. Possible connections between the function of IRE1 and the salt sensitivity are discussed.

Effect of light and auxin transport inhibitors on endoreduplication in hypocotyl and cotyledon

Enhancement of endoreduplication in dark-grown hypocotyl is a common feature in dicotyledonous polysomatic plants, and TIBA-mediated inhibition of the endoreduplication is partially due to abnormal actin organization. Many higher plant species use endoreduplication during cell differentiation. However, the mechanisms underlying this process have remained elusive. In this study, we examined endoreduplication in hypocotyls and cotyledons in response to light in some dicotyledonous plant species. Enhancement of endoreduplication was found in the dark-grown hypocotyls of all the polysomatic species analyzed across five different families, indicating that this process is a common feature in dicotyledonous plants having polysomatic tissues. Conversely, endoreduplication was enhanced in the light-grown cotyledons in four of the five species analyzed. We also analyzed the effect of a polar auxin transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA) on endoreduplication in hypocotyl and cotyledon tissues of radish (Raphanus sativus L. var. longipinnatus Bailey). TIBA was found to inhibit and promote endoreduplication in hypocotyls and cotyledons, respectively, suggesting that the endoreduplication mechanism differs in these organs. To gain insight into the effect of TIBA, radish and spinach (Spinacia oleracea L.) seedlings were treated with a vesicle-trafficking inhibitor, brefeldin A, and an actin polymerization inhibitor, cytochalasin D. Both of the inhibitors partially inhibited endoreduplication of the dark-grown hypocotyl tissues, suggesting that the prominent inhibition of endoreduplication by TIBA might be attributed to its multifaceted role.

Tunicamycin-induced inhibition of protein secretion into culture medium of Arabidopsis T87 suspension cells through mRNA degradation on the endoplasmic reticulum

The N-glycosylation inhibitor tunicamycin triggers endoplasmic reticulum stress response and inhibits efficient protein secretion in eukaryotes. Using Arabidopsis suspension cells, we showed that the reduced secretion of mannose-binding lectin 1 (MBL1) protein by tunicamycin is accompanied by a significant decrease in MBL1 mRNA, suggesting that mRNA destabilization is the major cause of the inhibition of protein secretion in plants.

Highly sensitive fluorescence detection of metastatic lymph nodes of gastric cancer with photo-oxidation of protoporphyrin IX

BACKGROUND

The establishment of a precise and rapid method to detect metastatic lymph nodes (LNs) is essential to perform less invasive surgery with reduced gastrectomy along with reduced lymph node dissection. We herein describe a novel imaging strategy to detect 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence in excised LNs specifically with reduced effects of tissue autofluorescence based on photo-oxidation of PpIX. We applied the method in a clinical setting, and evaluated its feasibility.

METHODS

To reduce the unfavorable effect of autofluorescence, we focused on photo-oxidation of PpIX: Following light irradiation, PpIX changes into another substance, photo-protoporphyrin, via an oxidative process, which has a different spectral peak, at 675 nm, whereas PpIX has its spectral peak at 635 nm. Based on the unique spectral alteration, fluorescence spectral imaging before and after light irradiation and subsequent originally-developed image processing was performed. Following in vitro study, we applied this method to a total of 662 excised LNs obtained from 30 gastric cancer patients administered 5-ALA preoperatively.

RESULTS

Specific visualization of PpIX was achieved in in vitro study. The method allowed highly sensitive detection of metastatic LNs, with sensitivity of 91.9% and specificity of 90.8% in the in vivo clinical trial. Receiver operating characteristic analysis indicated high diagnostic accuracy, with the area under the curve of 0.926.

CONCLUSIONS

We established a highly sensitive and specific 5-ALA-induced fluorescence imaging method applicable in clinical settings. The novel method has a potential to become a useful tool for intraoperative rapid diagnosis of LN metastasis.

CaMV-35S promoter sequence-specific DNA methylation in lettuce

KEY MESSAGE

We found 35S promoter sequence-specific DNA methylation in lettuce. Additionally, transgenic lettuce plants having a modified 35S promoter lost methylation, suggesting the modified sequence is subjected to the methylation machinery. We previously reported that cauliflower mosaic virus 35S promoter-specific DNA methylation in transgenic gentian (Gentiana triflora × G. scabra) plants occurs irrespective of the copy number and the genomic location of T-DNA, and causes strong gene silencing. To confirm whether 35S-specific methylation can occur in other plant species, transgenic lettuce (Lactuca sativa L.) plants with a single copy of the 35S promoter-driven sGFP gene were produced and analyzed. Among 10 lines of transgenic plants, 3, 4, and 3 lines showed strong, weak, and no expression of sGFP mRNA, respectively. Bisulfite genomic sequencing of the 35S promoter region showed hypermethylation at CpG and CpWpG (where W is A or T) sites in 9 of 10 lines. Gentian-type de novo methylation pattern, consisting of methylated cytosines at CpHpH (where H is A, C, or T) sites, was also observed in the transgenic lettuce lines, suggesting that lettuce and gentian share similar methylation machinery. Four of five transgenic lettuce lines having a single copy of a modified 35S promoter, which was modified in the proposed core target of de novo methylation in gentian, exhibited 35S hypomethylation, indicating that the modified sequence may be the target of the 35S-specific methylation machinery.

The polar auxin transport inhibitor TIBA inhibits endoreduplication in dark grown spinach hypocotyls

We addressed the question of whether an additional round of endoreduplication in dark-grown hypocotyls is a common feature in dicotyledonous plants having endopolyploid tissues. Ploidy distributions of hypocotyl tissues derived from in vitro-grown spinach (Spinacia oleracea L. cv. Atlas) seedlings grown under different light conditions were analyzed by flow cytometry. An additional round of endoreduplication (represented by 32C cells) was found in the dark-grown hypocotyl tissues. This response was inhibited by light, the intensity of which is a crucial factor for the inhibition of endoreduplication. The higher ploidy cells in cortical tissues of the dark-grown hypocotyls had larger cell sizes, suggesting that the additional round of endoreduplication contributes to hypocotyl elongation. More importantly, a polar auxin transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA), strongly inhibits endoreduplication, not only in spinach but also in Arabidopsis. Because other polar auxin transport inhibitors or an auxin antagonist show no or mild effects, TIBA may have a specific feature that inhibits endoreduplication.

Sugar Responsible and Tissue Specific Expression of a Gene Encoding AtCIPK14, anArabidopsisCBL-Interacting Protein Kinase

Expression of AtCIPK14 (an Arabidopsis CBL-interacting protein kinase 14) was induced by metabolic sugars. Two A/T-rich sequences similar to elements involved in sugar-inducible expression of other genes were found within the -183 bp 5' region of the AtCIPK14 promoter that was responsible for the sugar induction. Histochemical analysis using a reporter gene indicated vascular-specific expression of AtCIPK14.

An attempt to detect siRNA-mediated genomic DNA modification by artificially induced mismatch siRNA in Arabidopsis

Although tremendous progress has been made in recent years in identifying molecular mechanisms of small interfering RNA (siRNA) functions in higher plants, the possibility of direct interaction between genomic DNA and siRNA remains an enigma. Such an interaction was proposed in the ‘RNA cache’ hypothesis, in which a mutant allele is restored based on template-directed gene conversion. To test this hypothesis, we generated transgenic Arabidopsis thaliana plants conditionally expressing a hairpin dsRNA construct of a mutated acetolactate synthase (mALS) gene coding sequence, which confers chlorsulfuron resistance, in the presence of dexamethasone (DEX). In the transgenic plants, suppression of the endogenous ALS mRNA expression as well as 21-nt mALS siRNA expression was detected after DEX treatment. After screening >100,000 progeny of the mALS siRNA-induced plants, no chlorsulfuron-resistant progeny were obtained. Further experiments using transgenic calli also showed that DEX-induced expression of mALS siRNA did not affect the number of chlorsulfuron-resistant calli. No trace of cytosine methylation of the genomic ALS region corresponding to the dsRNA region was observed in the DEX-treated calli. These results do not necessarily disprove the ‘RNA cache’ hypothesis, but indicate that an RNAi machinery for ALS mRNA suppression does not alter the ALS locus, either genetically or epigenetically.

Plant transducers of the endoplasmic reticulum unfolded protein response

The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response.

Plant transducers of the endoplasmic reticulum unfolded protein response

The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response.

Growth rates of abdominal aortic aneurysms in Japanese patients observed in one institute

AIM

The aim of this paper was to investigate the growth rate of abdominal aortic aneurysms (AAA) in Japanese patients.

METHODS

We retrospectively studied patients conservatively followed with infrarenal AAA in terms of AAA diameter measured using computed tomography (CT) in our hospital between 1999 and 2009. The AAA surgery criterion in our institute was a diameter ≥ 5.0 cm or a growth rate ≥5 mm/year. We estimated operation-free ratios by initial AAA diameter and changes in AAA growth rates. Patients with an initial AAA diameter < 5.0 cm were divided into 2 groups. Patients with AAA that met the criteria for surgery were classified into the expansion group, and those remaining into the non-expansion group. Their AAA growth rates were compared.

RESULTS

The group consisted of 124 patients (average age, 73.7±8.6 years (range 54-92)) who had at least 2 recorded AAA measurements. The average follow-up period was 3.0±2.2 years (range 0.3-10.2). There were no cases of rupture during follow-up. Twenty-six patients (21.0%) underwent surgery (open replacement [N.=20]; endovascular abdominal aneurysm repair [N.=6]). The growth rate determined from the initially measured diameter was significantly faster in AAAs measuring 5.0-5.4 cm than in AAAs measuring 4.5-4.9 cm (P=0.01). More than 90% of patients with an initial AAA diameter <5.0 cm were observed conservatively for 2 years or more. However, more than half of the patients with an initial AAA diameter ≥4.0 cm needed surgery within 5 years. The growth rates of AAAs for each size during growth were significantly faster when the AAA diameter was 4.5-4.9 cm than when it was 4.0-4.4 cm (P=0.006), and when the AAA diameter was 5.0-5.4 cm than when it was 4.5-4.9 cm (P = 0.009). The expansion and non-expansion groups consisted of 38 (34.2%) and 73 (75.8%) patients, respectively. The AAA growth rate in the expansion group was significantly faster than that in the non-expansion group (3.4±2.2 mm/year vs. 1.4±1.3 mm/year, P=0.0001).

CONCLUSION

It may be considered that the appropriate indication for AAA repair is defined by a diameter of 5.0 cm for Japanese patients. Patients with AAA that is growing continuously by ≥3 mm/year and who have low operative risk may undergo surgery even if their AAA is <5.0 cm.

Arabidopsis IRE1 catalyses unconventional splicing of bZIP60 mRNA to produce the active transcription factor

IRE1 plays an essential role in the endoplasmic reticulum (ER) stress response in yeast and mammals. We found that a double mutant of Arabidopsis IRE1A and IRE1B (ire1a/ire1b) is more sensitive to the ER stress inducer tunicamycin than the wild-type. Transcriptome analysis revealed that genes whose induction was reduced in ire1a/ire1b largely overlapped those in the bzip60 mutant. We observed that the active form of bZIP60 protein detected in the wild-type was missing in ire1a/ire1b. We further demonstrated that bZIP60 mRNA is spliced by ER stress, removing 23 ribonucleotides and therefore causing a frameshift that replaces the C-terminal region of bZIP60 including the transmembrane domain (TMD) with a shorter region without a TMD. This splicing was detected in ire1a and ire1b single mutants, but not in the ire1a/ire1b double mutant. We conclude that IRE1A and IRE1B catalyse unconventional splicing of bZIP60 mRNA to produce the active transcription factor.

Clinical comparison of two different types of bifurcated graft for postoperative baPWV and ABI

AIM

A newly-designed bifurcated graft with the distal end larger than the conventional type has been developed. The purpose of this study was to evaluate the early results of graft replacement using this new graft, and to compare whether the new graft is more advantageous than the conventional graft in terms of peripheral blood flow and arterial stiffness.

METHODS

Records of 36 patients who underwent bifurcated graft replacement for infrarenal abdominal aortic aneurysm (AAA), from May 2003 to September 2006 were reviewed after excluding peripheral arterial disease (ABI > 0.9). Subjects were divided into two groups: group C (N.=20), with implantation of the conventional type and group N (N.=16), with implantation of the new type. We investigated changes in brachial-ankle pulse wave velocity (baPWV) and ankle-brachial pressure index (ABI), measurements being performed preoperatively and postoperatively.

RESULTS

baPWV in the postoperative group as a whole was significantly higher than in the preoperative group (P<0.05), while ABI in the postoperative group was lower than in the preoperative group (P<0.05). In group C, baPWV increased (P<0.05) and ABI decreased (P<0.05) after bifurcated graft replacement, whereas in group N, there were no significant differences in changes of baPWV and ABI.

CONCLUSIONS

This study shows that the new graft reduces the development of arterial stiffness postoperatively compared with the conventional type. These results may predict the new type graft decrease in the risk of morbidity and mortality caused by atherosclerotic disease.

The Arabidopsis membrane-bound transcription factor AtbZIP60 is a novel plant-specific endoplasmic reticulum stress transducer

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) of eukaryotic cells triggers a protective response, termed the ER stress response or the unfolded protein response, to maintain cellular homeostasis. Recently we characterized the Arabidopsis (Arabidopsis thaliana) membrane-bound basic leucine zipper (bZIP) transcription factor AtbZIP60 involved in the ER stress response. We reported that AtbZIP60 is activated by regulated intramembrane proteolysis (RIP), a mechanism by which a membrane-bound transcription factor is released by proteolytic cleavage. We presented evidence that the AtbZIP60 protein resides in the ER membrane under unstressed conditions and is activated by proteolytic cleavage in response to ER stress to translocate into the nucleus where it acts as a transcription factor. Further analysis, however, showed that this cleavage is independent of the function of Arabidopsis homologs of S1P and S2P proteases, which mediate the proteolytic cleavage of the mammalian transcription factor ATF6. Thus AtbZIP60 is an ER stress transducer activated by a novel RIP mechanism that may be unique to plants.

Arabidopsis bZIP60 is a proteolysis-activated transcription factor involved in the endoplasmic reticulum stress response

Proteins synthesized in the endoplasmic reticulum (ER) of eukaryotic cells must be folded correctly before translocation out of the ER. Disruption of protein folding results in the induction of genes for ER-resident chaperones, for example, BiP. This phenomenon is known as the ER stress response. We report here that bZIP60, an Arabidopsis thaliana basic leucine zipper (bZIP) transcription factor with a transmembrane domain, is involved in the ER stress response. When compared with wild-type Arabidopsis plants, homozygous bzip60 mutant plants show a markedly weaker induction of many ER stress-responsive genes. The bZIP60 protein resides in the ER membrane under unstressed condition and is cleaved in response to ER stress caused by either tunicamycin or DTT. The N-terminal fragment containing the bZIP domain is then translocated into the nucleus. Cleavage of bZIP60 is independent of the function of Arabidopsis homologs of mammalian S1P and S2P proteases, which mediate the proteolytic cleavage of the mammalian transcription factor ATF6. In Arabidopsis, expression of the bZIP60 gene and cleavage of the bZIP60 protein are observed in anthers in the absence of stress treatment, suggesting that the ER stress response functions in the normal development of active secretory cells.

NtbZIP60, an endoplasmic reticulum-localized transcription factor, plays a role in the defense response against bacterial pathogens in Nicotiana tabacum

A spermine-based signal transduction pathway plays a defensive role against incompatible pathogens. We identified a novel spermine-responsive cDNA from Nicotiana tabacum that encodes a basic region/leucine zipper protein with a putative transmembrane domain. Identity to Arabidopsis thaliana AtbZIP60 was sufficiently high to name the novel cDNA NtbZIP60. Expression analysis revealed that NtbZIP60 is a component of the spermine-signal pathway, and is also involved in the unfolded protein response (UPR), as demonstrated for AtbZIP60. The gene product, NtbZIP60, localizes to the endoplasmic reticulum (ER) in plant cells; once the putative transmembrane domain is eliminated from the intact protein, it targets the nucleus. The putative processed form of NtbZIP60 transactivates target genes through binding to plant-specific UPR cis-elements. Expression of NbbZIP60, an NtbZIP60 ortholog in Nicotiana benthamiana, was significantly up-regulated at 6 h and later time points upon infection with the non-host pathogen Pseudomonas cichorii, while it was unaffected by infection with the compatible pathogen Pseudomonas syringae pv. tabaci. Furthermore, NbbZIP60-silenced N. benthamiana plants allowed higher multiplication of P. cichorii compared to the control plants. Taken together, the results suggest that this ER-localized transcription factor is involved in the spermine-signal transduction pathway and plays an important role in plant innate immunity.

Current progress and challenges in ocular surface reconstruction using cultivated epithelial sheet transplantation

The cultivated epithelial transplantation is a new surgical modality for treating a variety of severe ocular surface disorders. This type of tissue-engineered epithelial sheet provides a rapid epithelial coverage on the corneal surface that reduces inflammation and postoperative complications. Although cultivated corneal epithelial transplantation is an effective surgical strategy, autologous transplantation is limited to unilateral cases. Autologous cultivated oral mucosal epithelial transplantation (COMET) enables surgeons to reconstruct the ocular surface using autologous, non-ocular surface cells, and has opened a new pathway for treating severe, bilateral ocular surface disorders.