Exploring types of conversational agents for resolving cancer patients' questions and concerns: Analysis of 100 telephone consultations on breast cancer

OBJECTIVE

This study was conducted to investigate the types of conversational agents (CA) that can help address questions and concerns ("lay topics" [LTs]).

METHODS

We analyzed audio recordings of telephone consultations with 100 breast cancer patients and their families. (1) We identified the content and mode of expression of LTs about breast cancer raised during actual telephone consultations. (2) We checked for the presence of clue information (CI) that can help patients resolve their LTs.

RESULTS

None of the 805 LTs of the 100 callers were the same. Treatment-related questions occurred in 70 of the 100 consultations. CIs were present in 52.5% of the LTs.

CONCLUSION

The results suggest that chatbots (a type of CA) that offer CIs are more feasible than chatbots that answer each question directly in cancer consultations. Moreover, it is difficult to answer questions directly because preparing answers to all LTs in a breast cancer consultation is challenging owing to LT differences. Therefore, preparing high-quality CIs focused on treatments is required.

PRACTICE IMPLICATIONS

An increasing number of cancer patients are seeking information to resolve their LTs. CAs can help supplement the limited human resources available if they are supplied with appropriate CIs.

Real-Time Monitoring of Key Gene Products Involved in Rice Photoperiodic Flowering

Flowering is an important biological process through which plants determine the timing of reproduction. In rice, florigen mRNA is induced more strongly when the day length is shorter than the critical day length through recognition of 30-min differences in the photoperiod. Grain number, plant height, and heading date 7 (Ghd7), which encodes a CCT-domain protein unique to monocots, has been identified as a key floral repressor in rice, and Heading date 1 (Hd1), a rice ortholog of the Arabidopsis floral activator CONSTANS (CO), is another key floral regulator gene. The Hd1 gene product has been shown to interact with the Ghd7 gene product to form a strong floral repressor complex under long-day conditions. However, the mRNA dynamics of these genes cannot explain the day-length responses of their downstream genes. Thus, a real-time monitoring system of these key gene products is needed to elucidate the molecular mechanisms underlying accurate photoperiod recognition in rice. Here, we developed a monitoring system using luciferase (LUC) fusion protein lines derived from the Ghd7-LUC and Hd1-LUC genes. We successfully obtained a functionally complemented gene-targeted line for Ghd7-LUC. Using this system, we found that the Ghd7-LUC protein begins to accumulate rapidly after dawn and reaches its peak more rapidly under a short-day condition than under a long-day condition. Our system provides a powerful tool for revealing the accurate time-keeping regulation system incorporating these key gene products involved in rice photoperiodic flowering.

Acetic-acid-induced jasmonate signaling in root enhances drought avoidance in rice

Conferring drought resistant traits to crops is one of the major aims of current breeding programs in response to global climate changes. We previously showed that exogenous application of acetic acid to roots of various plants could induce increased survivability under subsequent drought stress conditions, but details of the metabolism of exogenously applied acetic acid, and the nature of signals induced by its application, have not been unveiled. In this study, we show that rice rapidly induces jasmonate signaling upon application of acetic acid, resulting in physiological changes similar to those seen under drought. The major metabolite of the exogenously applied acetic acid in xylem sap was determined as glutamine-a common and abundant component of xylem sap-indicating that acetic acid is not the direct agent inducing the observed physiological responses in shoots. Expression of drought-responsive genes in shoot under subsequent drought conditions was attenuated by acetic acid treatment. These data suggest that acetic acid activates root-to-shoot jasmonate signals that partially overlap with those induced by drought, thereby conferring an acclimated state on shoots prior to subsequent drought.

Specific region affects the difference in accumulation levels between apple food allergen Mal d 1 and birch pollen allergen Bet v 1 which are expressed in vegetative tissues of transgenic rice

Specific domain of the Mal d 1 was identified to be mainly involved in higher accumulation level in vegetative tissues of transgenic rice than the Bet v 1. Apple food allergen Mal d 1 and birch pollen allergen Bet v 1 belong to the same pathogen related protein 10 (PR10) family. When green fluorescent protein (GFP) fused to either of these allergens was expressed as a secretory protein in transgenic rice by ligating an N terminal signal peptide and a C terminal KDEL ER retention signal under the control of the maize ubiquitin constitutive promoter, the GFP:Mald1 highly accumulated in various tissues, whereas accumulation level of the GFP:Betv1 was remarkably reduced in vegetative tissues except for seed. Analysis by RT-PCR exhibited that there was little difference in their transcript levels, indicating the involvement of post-transcriptional regulation. To investigate the cause of such difference in accumulation levels, deletion analysis of the Mal d 1 and domain swapping between them were carried out in transgenic rice. The results showed that the region between positions 41-90 in the Mal d 1 is predominantly implicated in higher level accumulation in vegetative tissues as well as seed as compared with the Bet v 1. The GFP:Mald1 was localized in oligomeric form within ER lumen or ER-derived particles in vegetative tissues, whereas in seed mainly deposited into novel huge ER-derived protein bodies with the size of 5-10 µm in aleurone cells.

Expression of Flavone Synthase II and Flavonoid 3'-Hydroxylase Is Associated with Color Variation in Tan-Colored Injured Leaves of Sorghum

Sorghum (Sorghum bicolor L. Moench) exhibits various color changes in injured leaves in response to cutting stress. Here, we aimed to identify key genes for the light brown and dark brown color variations in tan-colored injured leaves of sorghum. For this purpose, sorghum M36001 (light brown injured leaves), Nakei-MS3B (purple), and a progeny, #7 (dark brown), from Nakei-MS3B × M36001, were used. Accumulated pigments were detected by using high-performance liquid chromatography: M36001 accumulated only apigenin in its light brown leaves; #7 accumulated both luteolin and a small amount of apigenin in its dark brown leaves, and Nakei-MS3B accumulated 3-deoxyanthocyanidins (apigeninidin and luteolinidin) in its purple leaves. Apigenin or luteolin glucoside derivatives were also accumulated, in different proportions. Differentially expressed genes before and after cutting stress were identified by using RNA sequencing (RNA-seq). Integration of our metabolic and RNA-seq analyses suggested that expression of only flavone synthase II (FNSII) led to the synthesis of apigenin in M36001, expression of both FNSII and flavonoid 3'-hydroxylase (F3'H) led to the synthesis of apigenin and luteolin in #7, and expression of both flavanone 4-reductase and F3'H led to the synthesis of 3-deoxyanthocyanidins in Nakei-MS3B. These results suggest that expression of FNSII is related to the synthesis of flavones (apigenin and luteolin) and the expression level of F3'H is related to the balance of apigenin and luteolin. Expression of FNSII and F3'H is thus associated with dark or light brown coloration in tan-colored injured leaves of sorghum.

Transgenic rice seed expressing flavonoid biosynthetic genes accumulate glycosylated and/or acylated flavonoids in protein bodies

Plant-specialized (or secondary) metabolites represent an important source of high-value chemicals. In order to generate a new production platform for these metabolites, an attempt was made to produce flavonoids in rice seeds. Metabolome analysis of these transgenic rice seeds using liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry was performed. A total of 4392 peaks were detected in both transgenic and non-transgenic rice, 20-40% of which were only detected in transgenic rice. Among these, 82 flavonoids, including 37 flavonols, 11 isoflavones, and 34 flavones, were chemically assigned. Most of the flavonols and isoflavones were O-glycosylated, while many flavones were O-glycosylated and/or C-glycosylated. Several flavonoids were acylated with malonyl, feruloyl, acetyl, and coumaroyl groups. These glycosylated/acylated flavonoids are thought to have been biosynthesized by endogenous rice enzymes using newly synthesized flavonoids whose biosynthesis was catalysed by exogenous enzymes. The subcellular localization of the flavonoids differed depending on the class of aglycone and the glycosylation/acylation pattern. Therefore, flavonoids with the intended aglycones were efficiently produced in rice seeds via the exogenous enzymes introduced, while the flavonoids were variously glycosylated/acylated by endogenous enzymes. The results suggest that rice seeds are useful not only as a production platform for plant-specialized metabolites such as flavonoids but also as a tool for expanding the diversity of flavonoid structures, providing novel, physiologically active substances.

Generation of transgenic rice with reduced content of major and novel high molecular weight allergens

BACKGROUND

Rice seed proteins contain antigens that provoke allergic responses in some individuals with food allergy, particularly in those with cereal allergy, and these antigens can elicit clinical symptoms such as eczema and dermatitis. We previously generated transgenic rice with reduced accumulation of the three major allergens, which dramatically reduced the level of IgE binding from patients' sera. However, the transgenic rice still possesses allergenic reactivity. Recently, two globulin-like proteins were identified as candidates of novel high molecular weight (HMW) IgE-binding proteins that cause rice allergy.

RESULTS

We identified a glucosidase family encoded by four genes as novel HMW rice allergens based on IgE antibody reactivity from individuals with allergy to rice. To further reduce allergenicity, we generated transgenic rice with reduced accumulation of these HMW allergens. We crossed the rice with reduced HMW allergens and with reduced major allergens, and all major and HMW allergens were substantially reduced in the progeny of the crossed rice. Allergen suppression did not significantly alter accumulation patterns of seed storage proteins and protein folding enzymes. The sera of a portion of patients showed low IgE-binding to the crossed line, suggesting that the crossed line is effective for a portion of patients who are allergic to proteins other than major allergens.

CONCLUSIONS

The transgenic rice with reduced levels of all major and HMW allergens is thought to be an option for a portion of allergy patients with hypersensitive responses to various kinds of rice allergens.

Generation mechanism of novel, huge protein bodies containing wild type or hypoallergenic derivatives of birch pollen allergen Bet v 1 in rice endosperm

Tree pollen chimera 7 (TPC7), a hypoallergenic Bet v 1 tolerogen against birch pollen allergy, induces the formation of novel, huge protein bodies (referred to as TPC7 bodies) in rice endosperm, and is accumulated in high level. In the present study, we found that native Bet v 1 and TPC9, analog proteins of TPC7, were also deposited into novel protein bodies in rice endosperm. However, the novel protein bodies in Bet v 1 and TPC9 rice were much smaller and less abundant than those in TPC7 rice, reflected in lower amounts of accumulation of Bet v 1 and TPC9 than that of TPC7. A domain swapping experiment between TPC7 and Bet v 1 revealed that the latter half of TPC7 is important for the formation of the TPC7 body. We found that chaperons and folding enzymes such as BiP and protein disulfide isomerase were localized within the TPC7 body. TPC7 protein was extracted from TPC7 seeds as large aggregates with molecular masses greater than 669 kDa, or approximately 75 kDa under native or semi-native conditions. These TPC7 aggregates are thought to be responsible for the induction of TPC7 body formation. TPC7 accumulated to a maximum level of 550 μg/seed, which amounts to 23% of total seed protein, while Bet v 1 and TPC9 accumulated much lower levels. The TPC7 body represents a promising reservoir, which may serve as a fusion partner for high-level production and sequestering storage of recombinant proteins.

Spatial transcriptomes of iron-deficient and cadmium-stressed rice

Although the genes involved in metal homeostasis have been investigated over the past few decades, many genes related to metal homeostasis remain uncharacterized, and a comprehensive analysis of the expression of these genes is required. In the present study, we investigated the spatial gene expression profile of iron (Fe)-deficient and cadmium (Cd)-stressed Oryza sativa (rice) using laser microdissection and microarray analysis. Roots of Fe-deficient and Cd-stressed rice were separated into the vascular bundle, cortex, and epidermis plus exodermis. In addition, vascular bundles from new and old leaves at the lowest node, which are important for metal distribution, were analyzed separately. The spatial expression patterns were distinct in each tissue type. Fe deficiency and Cd stress also had significant effects on the transcriptomes, although these were less pronounced than the spatial effects. Genes encoding transporters involved in metal homeostasis, proteins associated with heavy metal detoxification, and phytohormone-related proteins were comprehensively investigated. Additionally, cis motifs involved in the regulation of these diverse expression changes in various tissue types were predicted. The spatial transcriptomes presented here provide novel insight into the molecular mechanisms of metal homeostasis.

Tissue-specific transcriptional profiling of iron-deficient and cadmium-stressed rice using laser capture microdissection

Several metals are essential nutrients for plants. However, they become toxic at high levels and deleteriously affect crop yield and quality. We recently reported the spatial gene expression profiles of iron (Fe)-deficient and cadmium (Cd)-stressed rice using laser microdissection and microarray analysis. The roots of Fe-deficient and Cd-stressed rice were separated into the vascular bundle (VB), cortex (Cor), and epidermis plus exodermis (EP). In addition, vascular bundles from new and old leaves at the lowest node, which are important for metal distribution, were analyzed separately (newDC and oldDC, respectively). Genes expressed in a tissue-specific manner in the VB, Cor, EP, newDC, and oldDC formed large clusters. The genes upregulated in all of the VB, Cor, and EP by Fe deficiency formed a substantial cluster that was smaller than the tissue-specific clusters. Significant numbers of genes expressed in newDC or oldDC were also expressed in VB in roots, suggesting that vascular bundles in the lowest nodes and roots have a partially common function. The expression patterns of transporter families involved in metal homeostasis were investigated, and members of each family were either expressed differentially in each tissue or showed different responses to Fe deficiency. One potassium transporter gene, OsHAK22, was upregulated by Fe deficiency in VB, Cor, and EP, suggesting that OsHAK22 is involved in potassium transport associated with mugineic acids secretion.

Development of a novel prediction method of cis-elements to hypothesize collaborative functions of cis-element pairs in iron-deficient rice

BACKGROUND

Cis-acting elements are essential genomic sequences that control gene expression. In higher eukaryotes, a series of cis-elements function cooperatively. However, further studies are required to examine the co-regulation of multiple cis-elements on a promoter. The aim of this study was to propose a model of cis-element networks that cooperatively regulate gene expression in rice under iron (Fe) deficiency.

RESULTS

We developed a novel clustering-free method, microarray-associated motif analyzer (MAMA), to predict novel cis-acting elements based on weighted sequence similarities and gene expression profiles in microarray analyses. Simulation of gene expression was performed using a support vector machine and based on the presence of predicted motifs and motif pairs. The accuracy of simulated gene expression was used to evaluate the quality of prediction and to optimize the parameters used in this method. Based on sequences of Oryza sativa genes upregulated by Fe deficiency, MAMA returned experimentally identified cis-elements responsible for Fe deficiency in O. sativa. When this method was applied to O. sativa subjected to zinc deficiency and Arabidopsis thaliana subjected to salt stress, several novel candidate cis-acting elements that overlap with known cis-acting elements, such as ZDRE, ABRE, and DRE, were identified. After optimization, MAMA accurately simulated more than 87% of gene expression. Predicted motifs strongly co-localized in the upstream regions of regulated genes and sequences around transcription start sites. Furthermore, in many cases, the separation (in bp) between co-localized motifs was conserved, suggesting that predicted motifs and the separation between them were important in the co-regulation of gene expression.

CONCLUSIONS

Our results are suggestive of a typical sequence model for Fe deficiency-responsive promoters and some strong candidate cis-elements that function cooperatively with known cis-elements.

Transgenic rice seed synthesizing diverse flavonoids at high levels: a new platform for flavonoid production with associated health benefits

Flavonoids possess diverse health-promoting benefits but are nearly absent from rice, because most of the genes encoding enzymes for flavonoid biosynthesis are not expressed in rice seeds. In the present study, a transgenic rice plant producing several classes of flavonoids in seeds was developed by introducing multiple genes encoding enzymes involved in flavonoid synthesis, from phenylalanine to the target flavonoids, into rice. Rice accumulating naringenin was developed by introducing phenylalanine ammonia lyase (PAL) and chalcone synthase (CHS) genes. Rice producing other classes of flavonoids, kaempferol, genistein, and apigenin, was developed by introducing, together with PAL and CHS, genes encoding flavonol synthase/flavanone-3-hydroxylase, isoflavone synthase, and flavone synthases, respectively. The endosperm-specific GluB-1 promoter or embryo- and aleurone-specific 18-kDa oleosin promoters were used to express these biosynthetic genes in seed. The target flavonoids of naringenin, kaempferol, genistein, and apigenin were highly accumulated in each transgenic rice, respectively. Furthermore, tricin was accumulated by introducing hydroxylase and methyltransferase, demonstrating that modification to flavonoid backbones can be also well manipulated in rice seeds. The flavonoids accumulated as both aglycones and several types of glycosides, and flavonoids in the endosperm were deposited into PB-II-type protein bodies. Therefore, these rice seeds provide an ideal platform for the production of particular flavonoids due to efficient glycosylation, the presence of appropriate organelles for flavonoid accumulation, and the small effect of endogenous enzymes on the production of flavonoids by exogenous enzymes.

Rice genes involved in phytosiderophore biosynthesis are synchronously regulated during the early stages of iron deficiency in roots

BACKGROUND

The rice transcription factors IDEF1, IDEF2, and OsIRO2 have been identified as key regulators of the genes that control iron (Fe) uptake, including the biosynthesis of mugineic acid-family phytosiderophores (MAs). To clarify the onset of Fe deficiency, changes in gene expression were examined by microarray analysis using rice roots at 3, 6, 9, 12, 24, and 36 h after the onset of Fe-deficiency treatment.

RESULTS

More than 1000 genes were found to be upregulated over a time course of 36 h. Expression of MAs-biosynthetic genes, OsIRO2, and the Fe3+-MAs complex transporter OsYSL15 was upregulated at the 24 h and 36 h time points. Moreover, these genes showed very similar patterns of expression changes, but their expression patterns were completely different from those of a metallothionein gene (OsIDS1) and the Fe2+-transporter genes OsIRT1 and OsIRT2. OsIDS1 expression was upregulated by the 6 h time point. The early induction of OsIDS1 expression was distinct from the other Fe-deficiency-inducible genes investigated and suggested a functional relationship with heavy-metal homeostasis during the early stages of Fe deficiency.

CONCLUSIONS

We showed that many genes related to MAs biosynthesis and transports were regulated by a distinct mechanism in roots. Furthermore, differences in expression changes and timing in response to Fe deficiency implied that different combinations of gene regulation mechanisms control the initial responses to Fe deficiency.

The OsHMA2 transporter is involved in root-to-shoot translocation of Zn and Cd in rice

Zinc (Zn) is an essential micronutrient for plants and humans. Cadmium (Cd) is a Zn analog and one of the most toxic heavy metals to humans. Here we investigated the role of the Zn/Cd transporter OsHMA2. OsHMA2:GFP fusion protein localized to the plasma membrane in onion epidermal cells. The yeast expressing OsHMA2 was able to reverse the growth defect in the presence of excess Zn. The expression of OsHMA2 in rice was observed mainly in the roots where OsHMA2 transcripts were abundant in vascular bundles. Furthermore, Zn and Cd concentrations of OsHMA2-suppressed rice decreased in the leaves, while the Zn concentration increased in the roots compared with the wild type (WT). These results suggest that OsHMA2 plays a role in Zn and Cd loading to the xylem and participates in root-to-shoot translocation of these metals in rice. Furthermore, the Cd concentration in the grains of OsHMA2-overexpressing rice as well as in OsSUT1-promoter OsHMA2 rice decreased to about half that of the WT, although the other metal concentrations were the same as in the WT. A phenotype that reduces only the Cd concentration in rice grains will be very useful for transgenic approaches to food safety.

Development of an efficient agrobacterium-mediated gene targeting system for rice and analysis of rice knockouts lacking granule-bound starch synthase (Waxy) and β1,2-xylosyltransferase

We have developed a high-frequency method for Agrobacterium-mediated gene targeting by combining an efficient transformation system using rice suspension-cultured calli and a positive/negative selection system. Compared with the conventional transformation system using calli on solid medium, transformation using suspension-cultured calli resulted in a 5- to 10-fold increase in the number of resistant calli per weight of starting material after positive/negative selection. Homologous recombination occurred in about 1.5% of the positive/negative selected calli. To evaluate the efficacy of our method, we show in this report that knockout rice plants containing either a disrupted Waxy (granule-bound starch synthase) or a disrupted Xyl (β1,2-xylosyltransferase) gene can be easily obtained by homologous recombination. Study of gene function using homologous recombination in higher plants can now be considered routine work as a direct result of this technical advance.

OsIRO2 is responsible for iron utilization in rice and improves growth and yield in calcareous soil

Iron (Fe) deficiency, a worldwide agricultural problem on calcareous soil with low Fe availability, is also a major human nutritional deficit. Plants induce Fe acquisition systems under conditions of low Fe availability. Previously, we reported that an Fe-deficiency-inducible basic helix-loop-helix (bHLH) transcription factor, OsIRO2, is responsible for regulation of the genes involved in Fe homeostasis in rice. Using promoter-GUS transformants, we showed that OsIRO2 is expressed throughout a plant's lifetime in a spatially and temporally similar manner to the genes OsNAS1, OsNAS2 and TOM1, which is involved in Fe absorption and translocation. During germination, OsIRO2 expression was detected in embryos. OsIRO2 expression in vegetative tissues was restricted almost exclusively to vascular bundles of roots and leaves, and to the root exodermis under Fe-sufficient conditions, and expanded to all tissues of roots and leaves in response to Fe deficiency. OsIRO2 expression was also detected in flowers and developing seeds. Plants overexpressing OsIRO2 grew better, and OsIRO2-repressed plants showed poor growth compared to non-transformant rice after germination. OsIRO2 overexpression also resulted in improved tolerance to low Fe availability in calcareous soil. In addition to increased Fe content in shoots, the overexpression plants accumulated higher amounts of Fe in seeds than non-transformants when grown on calcareous soil. These results suggest that OsIRO2 is synchronously expressed with genes involved in Fe homeostasis, and performs a crucial function in regulation not only of Fe uptake from soil but also Fe transport during germination and Fe translocation to grain during seed maturation.

The spatial expression and regulation of transcription factors IDEF1 and IDEF2

BACKGROUND AND AIMS

Under conditions of low iron availability, rice plants induce genes involved in iron uptake and utilization. The iron deficiency-responsive cis-acting element binding factors 1 and 2 (IDEF1 and IDEF2) regulate transcriptional response to iron deficiency in rice roots. Clarification of the functions of IDEF1 and IDEF2 could uncover the gene regulation mechanism.

METHODS

Spatial patterns of IDEF1 and IDEF2 expression were analysed by histochemical staining of IDEF1 and IDEF2 promoter-GUS transgenic rice lines. Expression patterns of the target genes of IDEF1 and IDEF2 were analysed using transformants with induced or repressed expression of IDEF1 or IDEF2 grown in iron-rich or in iron-deficient solutions for 1 d.

KEY RESULTS

IDEF1 and IDEF2 were highly expressed in the basal parts of the lateral roots and vascular bundles. IDEF1 and IDEF2 expression was dominant in leaf mesophyll and vascular cells, respectively. These expression patterns were similar under both iron-deficient and iron-sufficient conditions. IDEF1 was strongly expressed in pollen, ovaries, the aleurone layer and embryo. IDEF2 was expressed in pollen, ovaries and the dorsal vascular region of the endosperm. During seed germination, IDEF1 and IDEF2 were expressed in the endosperm and embryo. Expression of IDEF1 target genes was regulated in iron-rich roots similar to early iron-deficiency stages. In addition, the expression patterns of IDEF2 target genes were similar between iron-rich conditions and early or subsequent iron deficiency.

CONCLUSIONS

IDEF1 and IDEF2 are constitutively expressed during both vegetative and reproductive stages. The spatial expression patterns of IDEF1 and IDEF2 overlap with their target genes in restricted cell types, but not in all cells. The spatial expression patterns and gene regulation of IDEF1 and IDEF2 in roots are generally conserved under conditions of iron sufficiency and deficiency, suggesting complicated interactions with unknown factors for sensing and transmitting iron-deficiency signals.

The rice transcription factor IDEF1 is essential for the early response to iron deficiency, and induces vegetative expression of late embryogenesis abundant genes

Higher plants maintain iron homeostasis by regulating the expression of iron (Fe)-related genes in accordance with Fe availability. The transcription factor IDEF1 regulates the response to Fe deficiency in Oryza sativa (rice) by recognizing CATGC sequences within the Fe deficiency-responsive cis-acting element IDE1. To investigate the function of IDEF1 in detail, we analyzed the response to Fe deficiency in transgenic rice plants exhibiting induced or repressed IDEF1 expression. Fe-deficiency treatment in hydroponic culture revealed that IDEF1 knock-down plants are susceptible to early-stage Fe deficiency, in contrast to IDEF1-induced plants. Time-course expression analyses using quantitative reverse-transcriptase PCR revealed that the IDEF1 expression level was positively correlated with the level of induction of the Fe utilization-related genes OsIRO2, OsYSL15, OsIRT1, OsYSL2, OsNAS1, OsNAS2, OsNAS3 and OsDMAS1, just after the onset of Fe starvation. However, this overall transactivation mediated by IDEF1 became less evident in subsequent stages. Microarray and in-silico analyses revealed that genes positively regulated by IDEF1, especially at the early stage, exhibit over-representation of CATGC and IDE1-like elements within the proximal promoter regions. These results indicate the existence of early and subsequent responses to Fe deficiency, with the former requiring IDEF1 more specifically. Proximal regions of IDEF1-regulated gene promoters also showed enrichment of RY elements (CATGCA), which regulate gene expression during seed maturation. The expression of several genes encoding late embryogenesis abundant proteins, including Osem, was induced in Fe-deficient roots and/or leaves in an IDEF1-dependent manner, suggesting a possible function of seed maturation-related genes in Fe-deficient vegetative organs.

A novel NAC transcription factor, IDEF2, that recognizes the iron deficiency-responsive element 2 regulates the genes involved in iron homeostasis in plants

Iron is essential for most living organisms, and thus iron deficiency poses a major abiotic stress in crop production. Plants induce iron utilization systems under conditions of low iron availability, but the molecular mechanisms of gene regulation under iron deficiency remain largely unknown. We identified a novel transcription factor of rice and barley, IDEF2, which specifically binds to the iron deficiency-responsive cis-acting element 2 (IDE2) by yeast one-hybrid screening. IDEF2 belongs to an uncharacterized branch of the NAC transcription factor family and exhibits novel properties of sequence recognition. An electrophoretic mobility shift assay and cyclic amplification and selection of targets experiment revealed that IDEF2 predominantly recognized CA(A/C)G(T/C)(T/C/A)(T/C/A) within IDE2 as the core-binding site. IDEF2 transcripts are constitutively present in rice roots and leaves. Repression of the function of IDEF2 by the RNA interference (RNAi) technique and chimeric repressor gene-silencing technology (CRES-T) caused aberrant iron homeostasis in rice. Several genes up-regulated by iron deficiency, including the Fe(II)-nicotianamine transporter gene OsYSL2, were less induced by iron deficiency in the RNAi rice of IDEF2, suggesting that IDEF2 is involved in the regulation of these genes. Many genes with repressed expression in IDEF2 RNAi rice possessed the IDEF2-binding core sites in their promoters, and the flanking sequences were also highly homologous to IDE2. IDEF2 bound to OsYSL2 promoter region containing the binding core site, suggesting direct regulation of OsYSL2 expression. These results reveal novel cis-element/trans-factor interactions functionally associated with iron homeostasis.

The transcription factor IDEF1 regulates the response to and tolerance of iron deficiency in plants

Iron is essential for most living organisms and is often the major limiting nutrient for normal growth. Plants induce iron utilization systems under conditions of low iron availability, but the molecular mechanisms of gene regulation under iron deficiency remain largely unknown. We identified the rice transcription factor IDEF1, which specifically binds the iron deficiency-responsive cis-acting element IDE1. IDEF1 belongs to an uncharacterized branch of the plant-specific transcription factor family ABI3/VP1 and exhibits the sequence recognition property of efficiently binding to the CATGC sequence within IDE1. IDEF1 transcripts are constitutively present in rice roots and leaves. Transgenic tobacco plants expressing IDEF1 under the control of the constitutive cauliflower mosaic virus 35S promoter transactivate IDE1-mediated expression only in iron-deficient roots. Transgenic rice plants expressing an introduced IDEF1 exhibit substantial tolerance to iron deficiency in both hydroponic culture and calcareous soil. IDEF1 overexpression leads to the enhanced expression of the iron deficiency-induced transcription factor gene OsIRO2, suggesting the presence of a sequential gene regulatory network. These findings reveal cis element/trans factor interactions that are functionally linked to the iron deficiency response. Manipulation of IDEF1 also provides another approach for producing crops tolerant of iron deficiency to enhance food and biomass production in calcareous soils.

The rice bHLH protein OsIRO2 is an essential regulator of the genes involved in Fe uptake under Fe-deficient conditions

Iron (Fe) deficiency is a major abiotic stress in crop production. Although responses to Fe deficiency in graminaceous plants, such as increased production and secretion of mugineic acid family phytosiderophores (MAs), have been described, the gene regulation mechanisms related to these responses are largely unknown. To elucidate the regulation mechanisms of the genes related to Fe acquisition in graminaceous plants, we characterized the Fe-deficiency-inducible basic helix-loop-helix transcription factor OsIRO2 in rice. In yeast cells, OsIRO2 functioned as a transcriptional activator. In rice, overexpression of OsIRO2 resulted in increased MAs secretion, whereas repression of OsIRO2 resulted in lower MAs secretion and hypersensitivity to Fe deficiency. Northern blots revealed that the expression of the genes involved in the Fe(III)-MAs transport system was dependent on OsIRO2. The expression of the genes for nicotianamine synthase, a key enzyme in MAs synthesis, was notably affected by the level of OsIRO2 expression. Microarray analysis demonstrated that OsIRO2 regulates 59 Fe-deficiency-induced genes in roots. Some of these genes, including two transcription factors upregulated by Fe deficiency, possessed the OsIRO2 binding sequence in their upstream regions. OsIRO2 possesses a homologous sequence of the Fe-deficiency-responsive cis-acting elements (IDEs) in its upstream region. We propose a novel gene regulation network for Fe-deficiency responses, including OsIRO2, IDEs and the two transcription factors.

Isolation and characterization of IRO2, a novel iron-regulated bHLH transcription factor in graminaceous plants

To clarify the molecular mechanism that regulates iron (Fe) acquisition in graminaceous plants, a time-course analysis of gene expression during Fe deficiency stress was conducted using a rice 22K oligo-DNA microarray. Twenty-one genes for proteins that function in gene regulation were induced by Fe deficiency. Of these genes, a putative basic helix-loop-helix (bHLH) transcription factor gene, named OsIRO2, was strongly expressed in both roots and shoots during Fe deficiency stress. The expression of OsIRO2 was induced exclusively by Fe deficiency, and not by deficiencies in other metals. Expression of the barley HvIRO2 gene, which is a homologue of OsIRO2, was also induced by Fe deficiency. An in silico search revealed that IRO2 is highly conserved among graminaceous plants, which include wheat, sorghum, and maize. The cyclic amplification and selection of targets (CASTing) technique revealed that OsIRO2 bound preferentially to the sequence 5'-ACCACGTGGTTTT-3', and the electrophoretic mobility shift assay revealed 5'-CACGTGG-3' as the core sequence for OsIRO2 binding. Sequences similar to the OsIRO2-binding sequence were found upstream of several genes that are involved in Fe acquisition, such as OsNAS1, OsNAS3, OsIRT1, OsFDH, OsAPT1, and IDS3. The core sequence of the OsIRO2-binding sequence occurred more frequently in the upstream regions of Fe deficiency-inducible genes than in the corresponding regions of non-inducible genes. These results suggest that IRO2 is involved in the regulation of gene expression under Fe-deficient conditions.

A case of drug-induced hypersensitivity syndrome showing transient immunosuppression before viral reactivation during treatment for pemphigus foliaceus

Drug-induced hypersensitivity syndrome (DIHS) is one of the most severe drug adverse reactions, with characteristic biphasic symptoms. Reactivation of human herpesvirus-6 (HHV-6) is frequently observed, although the cause of DIHS is still unknown. A patient developed DIHS during treatment with diaminodiphenylsulphone for pemphigus foliaceus. The number of lymphocytes in his peripheral blood, and titres of serum total IgG and IgM and anti-desmoglein1 antibody transiently decreased just before reactivation of HHV-6, cytomegalovirus and Epstein-Barr virus. This observation suggests that transient suppression of both cellular and humoral immunity may trigger viral reactivation, which leads to the development of the second phase of DIHS.

Improved growth response of antibody/receptor chimera attained by the engineering of transmembrane domain

Structure-based design of antibody/cytokine receptor chimeras has permitted a growth signal transduction in response to non-natural ligands such as fluorescein-conjugated BSA as mimicry of cytokine-cytokine receptor systems. However, while tight on/off regulation is observed in the natural cytokine receptor systems, many chimeras constructed to date showed residual growth-promoting activity in the absence of ligands. Here we tried to reduce the basal growth signal intensity from a chimera by engineering the transmembrane domain (TM) that is thought to be involved in the interchain interaction of natural cytokine receptors. When the retroviral vectors encoding the chimeras with either the wild-type erythropoietin receptor (EpoR) TM or the one bearing two mutations in the leucine zipper motif were transduced to non-strictly interleukin-6-dependent 7TD1 cells, a tight antigen-dependent on/off regulation was attained, also demonstrating the first antigen-mediated genetically modified cell amplification of non-strictly factor-dependent cells. The results clearly indicate that the TM mutation is an effective means to improve the growth response of the antibody/receptor chimera.

Quiet MRI with novel acoustic noise reduction

Fast scan techniques, which are used to reduce scanning times, have raised scanning noise levels in magnetic resonance imaging (MRI) systems, resulting in greater patient discomfort and stress. It is well known that this noise is caused by vibration of the gradient coil due to the Lorentz forces generated by the current in the gradient coil, which is placed in a static magnetic field. We have confirmed that MRI noise can be substantially reduced by sealing the gradient coil in a vacuum chamber to block airborne vibration propagation, by supporting the gradient coil independently to block solid vibration propagation and by decreasing the eddy currents induced in RF coils, the RF shield and the static-field-magnet cryostat. Based on these findings, we have developed a silent MRI system in which scanning noise is markedly reduced under a wide range of scanning conditions.

[Ask-Upmark kidney: a case report]

A case of Ask-Upmark kidney is presented. An 18-year-old male patient referred to this facility presented with symptoms of hypertension, microscopic hematuria and proteinuria. A hormonal study revealed a high plasma renin activity level. Intravenous pyelography and abdominal computed tomography revealed thinning of the cortex with calyceal dilatation. Arteriography revealed a deep cortical groove in the middle portion of the kidney without renal arterial stenosis. Plasma renin activity of the left renal vein was significantly higher than that of the right renal vein. A left simple nephrectomy was performed under the diagnosis of Ask-Upmark kidney. Postoperatively, plasma renin activity returned to the normal range and a decrease in blood pressure was noted. Recent reports have suggested Ask-Upmark kidney to be a consequence of vesicoureteral reflux rather than a true congenital malformation. Our case indicated no evidence of vesicoureteral reflux and suggests that the lesion was congenital rather than acquired.

Accumulation of hypotaurine in tissues and urine of rats fed an excess methionine diet

Hypotaurine increased in some tissues, especially in muscle, and urine of rats fed methionine excess diet. The significant depression of the body weight and food intake of rats caused by excess methionine was remarkably alleviated as previous reports and hypotaurine content in muscle and urine increased further by supplement with glycine to the excess methionine diet.