Molecular mechanisms of self-incompatibility in Brassicaceae and Solanaceae

Self-incompatibility (SI) is a mechanism for preventing self-fertilization in flowering plants. SI is controlled by a single S-locus with multiple haplotypes (S-haplotypes). When the pistil and pollen share the same S-haplotype, the pollen is recognized as self and rejected by the pistil. This review introduces our research on Brassicaceae and Solanaceae SI systems to identify the S-determinants encoded at the S-locus and uncover the mechanisms of self/nonself-discrimination and pollen rejection. The recognition mechanisms of SI systems differ between these families. A self-recognition system is adopted by Brassicaceae, whereas a collaborative nonself-recognition system is used by Solanaceae. Work by our group and subsequent studies indicate that plants have evolved diverse SI systems.

Comprehensive computational analysis of the SRK-SP11 molecular interaction underlying self-incompatibility in Brassicaceae using improved structure prediction for cysteine-rich proteins

Plants employ self-incompatibility (SI) to promote cross-fertilization. In Brassicaceae, this process is regulated by the formation of a complex between the pistil determinant S receptor kinase (SRK) and the pollen determinant S-locus protein 11 (SP11, also known as S-locus cysteine-rich protein, SCR). In our previous study, we used the crystal structures of two eSRK-SP11 complexes in Brassica rapa S8 and S9 haplotypes and nine computationally predicted complex models to demonstrate that only the SRK ectodomain (eSRK) and SP11 pairs derived from the same S haplotype exhibit high binding free energy. However, predicting the eSRK-SP11 complex structures for the other 100 + S haplotypes and genera remains difficult because of SP11 polymorphism in sequence and structure. Although protein structure prediction using AlphaFold2 exhibits considerably high accuracy for most protein monomers and complexes, 46% of the predicted SP11 structures that we tested showed < 75 mean per-residue confidence score (pLDDT). Here, we demonstrate that the use of curated multiple sequence alignment (MSA) for cysteine-rich proteins significantly improved model accuracy for SP11 and eSRK-SP11 complexes. Additionally, we calculated the binding free energies of the predicted eSRK-SP11 complexes using molecular dynamics (MD) simulations and observed that some Arabidopsis haplotypes formed a binding mode that was critically different from that of B. rapa S8 and S9. Thus, our computational results provide insights into the haplotype-specific eSRK-SP11 binding modes in Brassicaceae at the residue level. The predicted models are freely available at Zenodo, https://doi.org/10.5281/zenodo.8047768.

MLPK function is not required for self-incompatibility in the S29 haplotype of Brassica rapa L

S²⁹ haplotype does not require the MLPK function for self-incompatibility in Brassica rapa. Self-incompatibility (SI) in Brassicaceae is regulated by the self-recognition mechanism, which is based on the S-haplotype-specific direct interaction of the pollen-derived ligand, SP11/SCR, and the stigma-side receptor, SRK. M locus protein kinase (MLPK) is known to be one of the positive effectors of the SI response. MLPK directly interacts with SRK, and is phosphorylated by SRK in Brassica rapa. In Brassicaceae, MLPK was demonstrated to be essential for SI in B. rapa and Brassica napus, whereas it is not essential for SI in Arabidopsis thaliana (with introduced SRK and SP11/SCR from related SI species). Little is known about what determines the need for MLPK in SI of Brassicaceae. In this study, we investigated the relationship between S-haplotype diversity and MLPK function by analyzing the SI phenotypes of different S haplotypes in a mlpk/mlpk mutant background. The results have clarified that in B. rapa, all the S haplotypes except the S²⁹ we tested need the MLPK function, but the S²⁹ haplotype does not require MLPK for the SI. Comparative analysis of MLPK-dependent and MLPK-independent S haplotype might provide new insight into the evolution of S-haplotype diversity and the molecular mechanism of SI in Brassicaceae.

Spatiogenetic characterization of S receptor kinase (SRK) alleles in naturalized populations of Raphanus sativus L. var. raphanistroides on Yakushima island

In various coastal areas of Japan, naturalized radish populations are observed. Radish is a cruciferous plant and exhibits self-incompatibility, involving a system controlled by a single locus with multiple S alleles. Although the S allele diversity of radish cultivars and wild radishes has been characterized, the S allele distribution in naturalized populations has not yet been analyzed in relation to the positions of the plants in situ. Here, we show the S allele distribution in naturalized radish populations of Yakushima, a small island in the East China Sea, with positions of the plants. Radish plants were sampled in coastal areas in Yakushima, and their S alleles were detected and characterized. Most of the S alleles had been previously identified in radish cultivars. However, four novel S alleles, which may be unique to Yakushima, were also found. Moreover, seeds in siliques from plants growing in the study areas were sampled, and S allele determination in DNA extracted from these seeds suggested that the plants had exchanged their pollen among their close neighbors. There was also a problem in that the PCR amplification of some SRK alleles was difficult because of their sequence diversity in the naturalized populations, as occurs in cultivars. Our results suggest that the exchange of S alleles between cultivars and naturalized populations occurs and that S alleles in naturalized populations are highly diverse. The methodology established in our study should be applicable to other self-incompatible species to dissect the diversity of S allele distribution in naturalized populations.

Mechanism of self/nonself-discrimination in Brassica self-incompatibility

Self-incompatibility (SI) is a breeding system that promotes cross-fertilization. In Brassica, pollen rejection is induced by a haplotype-specific interaction between pistil determinant SRK (S receptor kinase) and pollen determinant SP11 (S-locus Protein 11, also named SCR) from the S-locus. Although the structure of the B. rapa S₉-SRK ectodomain (eSRK) and S₉-SP11 complex has been determined, it remains unclear how SRK discriminates self- and nonself-SP11. Here, we uncover the detailed mechanism of self/nonself-discrimination in Brassica SI by determining the S₈-eSRK-S₈-SP11 crystal structure and performing molecular dynamics (MD) simulations. Comprehensive binding analysis of eSRK and SP11 structures reveals that the binding free energies are most stable for cognate eSRK-SP11 combinations. Residue-based contribution analysis suggests that the modes of eSRK-SP11 interactions differ between intra- and inter-subgroup (a group of phylogenetically neighboring haplotypes) combinations. Our data establish a model of self/nonself-discrimination in Brassica SI.

Dioctatin Activates ClpP to Degrade Mitochondrial Components and Inhibits Aflatoxin Production

Aflatoxin contamination of crops is a serious problem worldwide. Utilization of aflatoxin production inhibitors is attractive, as the elucidation of their modes of action contributes to clarifying the mechanism of aflatoxin production. Here, we identified mitochondrial protease ClpP as the target of dioctatin, an inhibitor of aflatoxin production of Aspergillus flavus. Dioctatin conferred uncontrolled caseinolytic capacity on ClpP of A. flavus and Escherichia coli. Dioctatin-bound ClpP selectively degraded mitochondrial energy-related proteins in vitro, including a subunit of respiratory chain complex V, which was also reduced by dioctatin in a ClpP-dependent manner in vivo. Dioctatin enhanced glycolysis and alcohol fermentation while reducing tricarboxylic acid cycle metabolites. These disturbances were accompanied by reduced histone acetylation and reduced expression of aflatoxin biosynthetic genes. Our results suggest that dioctatin inhibits aflatoxin production by inducing ClpP-mediated degradation of mitochondrial energy-related components, and that mitochondrial energy metabolism functions as a key determinant of aflatoxin production.

Genetic and tissue-specific RNA-sequencing analysis of self-compatible mutant TSC28 in Brassica rapa L. toward identification of a novel self-incompatibility factor

Self-incompatibility (SI) is a sophisticated system for pollen selectivity to prevent pollination by genetically identical pollen. In Brassica, it is genetically controlled by a single, highly polymorphic S-locus, and the male and female S-determinant factors have been identified as S-locus protein 11 (SP11)/S-locus cysteine-rich protein (SCR) and S-locus receptor kinase (SRK), respectively. However, the overall molecular system and identity of factors in the downstream cascade of the SI reaction remain unclear. Previously, we identified a self-compatible B. rapa mutant line, TSC28, which has a disruption in an unidentified novel factor of the SI signaling cascade. Here, in a genetic analysis of TSC28, using an F₂ population from a cross with the reference B. rapa SI line Chiifu-401, the causal gene was mapped to a genetic region of DNA containing markers BrSA64 and ACMP297 in B. rapa chromosome A1. By fine mapping using an F₂ population of 1,034 plants, it was narrowed down to a genetic region between DNA markers ACMP297 and BrgMS4028, with physical length approximately 1.01 Mbp. In this genomic region, 113 genes are known to be located and, among these, we identified 55 genes that were expressed in the papilla cells. These are candidates for the gene responsible for the disruption of SI in TSC28. This list of candidate genes will contribute to the discovery of a novel downstream factor in the SP11-SRK signaling cascade in the Brassica SI system.

Duplicated pollen-pistil recognition loci control intraspecific unilateral incompatibility in Brassica rapa

In plants, cell-cell recognition is a crucial step in the selection of optimal pairs of gametes to achieve successful propagation of progeny. Flowering plants have evolved various genetic mechanisms, mediated by cell-cell recognition, to enable their pistils to reject self-pollen, thus preventing inbreeding and the consequent reduced fitness of progeny (self-incompatibility, SI), and to reject foreign pollen from other species, thus maintaining species identity (interspecific incompatibility)¹. In the genus Brassica, the SI system is regulated by an S-haplotype-specific interaction between a stigma-expressed female receptor (S receptor kinase, SRK) and a tapetum cell-expressed male ligand (S locus protein 11, SP11), encoded by their respective polymorphic genes at the S locus^2-6. However, the molecular mechanism for recognition of foreign pollen, leading to reproductive incompatibility, has not yet been identified. Here, we show that recognition between a novel pair of proteins, a pistil receptor SUI1 (STIGMATIC UNILATERAL INCOMPATIBILITY 1) and a pollen ligand PUI1 (POLLEN UNILATERAL INCOMPATIBILITY 1), triggers unilateral reproductive incompatibility between plants of two geographically distant self-incompatible Brassica rapa lines, even though crosses would be predicted to be compatible based on the S haplotypes of pollen and stigma. Interestingly, SUI1 and PUI1 are similar to the SI genes, SRK and SP11, respectively, and are maintained as cryptic incompatibility genes in these two populations. The duplication of the SRK and SP11 followed by reciprocal loss in different populations would provide a molecular mechanism of the emergence of a reproductive barrier in allopatry.

Structure of the SHR-SCR heterodimer bound to the BIRD/IDD transcriptional factor JKD

The plant-specific GAI, RGA and SCR (GRAS) family proteins play critical roles in plant development and signalling. Two GRAS proteins, SHORT-ROOT (SHR) and SCARECROW (SCR), cooperatively direct asymmetric cell division and the patterning of root cell types by transcriptional control in conjunction with BIRD/INDETERMINATE DOMAIN (IDD) transcription factors, although precise details of these specific interactions and actions remain unknown. Here, we present the crystal structures of the SHR-SCR binary and JACKDAW (JKD)/IDD10-SHR-SCR ternary complexes. Each GRAS domain comprises one α/β core subdomain with an α-helical cap that mediates heterodimerization by forming an intermolecular helix bundle. The α/β core subdomain of SHR forms the BIRD binding groove, which specifically recognizes the zinc fingers of JKD. We identified a conserved SHR-binding motif in 13 BIRD/IDD transcription factors. Our results establish a structural basis for GRAS-GRAS and GRAS-BIRD interactions and provide valuable clues towards our understanding of these regulators, which are involved in plant-specific signalling networks.

Abstract P2-05-27: Baseline serum CA15-3 levels are associated with prognosis for breast cancer patients with non-complete pathological response to neoadjuvant chemotherapy

Background: It has been well demonstrated that patients who achieved pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) had a favorable prognosis compared with patients who did not (non-pCR). Even though pCR was not attained, reduction in tumor volume after chemotherapy may be associated with improved prognosis for a certain number of patients. However, the association between residual tumor volume and prognosis is not necessarily consistent. In order to identify substitute markers for breast cancer patients with non-pCR after NAC, we investigated the impact of serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA15-3) at baseline as well as post-NAC.

Patients and Methods: Ninety-six breast cancer patients treated with NAC and operated on at the Hyogo College of Medicine were recruited for this study. Serum CEA and CA15-3 were measured prior to chemotherapy as well as at completion of pre-operative treatment. The optimal cutoff points for CEA (1.55ng/m, normal range: &lt;5.0ng/ml) and CA15-3 (13.25U/ml, normal range: &lt;28.0U/ml) for relapse-free survival (RFS) were determined by analyzing the area under receiver operating characteristic curves in another study involving 613 breast cancer patients. Expression levels of Ki67 in samples obtained at pre- and post-NAC were also determined by means of immunohistochemical staining. Pathological complete response was classified as the absence of residual invasive cancer in the breast and lymph nodes. During a 2.13 years median follow-up period, 15 patients suffered relapse.

Results: pCR and non-pCR was attained by 21 and 75 patients, respectively. For the non-pCR patients, serum CEA levels at baseline were classified into high (n=35) and low (n=38) and serum CA15-3 levels at baseline into high (n=31) and low (n=43). RFS of non-pCR patients with high serum CA15-3 levels was significantly worse than of those with low levels (3-year RFS: 0.47 vs 0.93; p=0.0009). RFS for patients with high and low serum levels of CA15-3 after NAC was also significantly different (p=0.037). As for CEA, no significant association with RFS was observed either at baseline or post-NAC. Univariate analysis demonstrated that tumor size and baseline CA15-3 were significant prognostic factors for RFS. Multivariate analysis showed that both tumor size (hazard ratio (HR): 3.88, 95% confidence interval (CI): 1.21-12.35, p=0.023) and baseline CA15-3 (HR: 13.51, 95% CI: 1.74-105.08, p=0.013) were significant and independent risk factors for relapse. As for lymph node metastasis, tumor grade, residual tumor size and pre- and post-NAC Ki67 expression levels of patients with non-pCR showed no significant association with RFS.

Conclusion and discussion: High levels of serum CA15-3 at baseline constituted a significantly worse prognosis for breast cancer patients with non-pCR. Tumor size at baseline but not residual size and baseline CA15-3 seems to suitable as a substitute for prediction of outcome for patients with non-pCR. Our findings suggest that these markers may be useful for identifying patients with poor prognosis who may be candidates for additional adjuvant treatment.

Citation Format: Fujimoto Y, Imamura M, Higuchi T, Nishimukai A, Yanai A, Miyagawa Y, Murase K, Takatsuka Y, Miyoshi Y. Baseline serum CA15-3 levels are associated with prognosis for breast cancer patients with non-complete pathological response to neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-27.

A complex dominance hierarchy is controlled by polymorphism of small RNAs and their targets

In diploid organisms, phenotypic traits are often biased by effects known as Mendelian dominant-recessive interactions between inherited alleles. Phenotypic expression of SP11 alleles, which encodes the male determinants of self-incompatibility in Brassica rapa, is governed by a complex dominance hierarchy^1-3. Here, we show that a single polymorphic 24 nucleotide small RNA, named SP11 methylation inducer 2 (Smi2), controls the linear dominance hierarchy of the four SP11 alleles (S₄₄ > S₆₀ > S₄₀ > S₂₉). In all dominant-recessive interactions, small RNA variants derived from the linked region of dominant SP11 alleles exhibited high sequence similarity to the promoter regions of recessive SP11 alleles and acted in trans to epigenetically silence their expression. Together with our previous study⁴, we propose a new model: sequence similarity between polymorphic small RNAs and their target regulates mono-allelic gene expression, which explains the entire five-phased linear dominance hierarchy of the SP11 phenotypic expression in Brassica.

MYB transcription factor gene involved in sex determination in Asparagus officinalis

Dioecy is a plant mating system in which individuals of a species are either male or female. Although many flowering plants evolved independently from hermaphroditism to dioecy, the molecular mechanism underlying this transition remains largely unknown. Sex determination in the dioecious plant Asparagus officinalis is controlled by X and Y chromosomes; the male and female karyotypes are XY and XX, respectively. Transcriptome analysis of A. officinalis buds showed that a MYB-like gene, Male Specific Expression 1 (MSE1), is specifically expressed in males. MSE1 exhibits tight linkage with the Y chromosome, specific expression in early anther development and loss of function on the X chromosome. Knockout of the MSE1 orthologue in Arabidopsis induces male sterility. Thus, MSE1 acts in sex determination in A. officinalis.

Cullin1-P is an Essential Component of Non-Self Recognition System in Self-Incompatibility in Petunia

Self-incompatibility (SI) in flowering plants is a genetic reproductive barrier to distinguish self- and non-self pollen to promote outbreeding. In Solanaceae, self-pollen is rejected by the ribonucleases expressed in the styles (S-RNases), via its cytotoxic function. On the other side, the male-determinant is the S-locus F-box proteins (SLFs) expressed in pollen. Multiple SLFs collaboratively detoxify non-self S-RNases, therefore, non-self recognition is the mode of self-/non-self discrimination in Solanaceae. It is considered that SLFs function as a substrate-recognition module of the Skp1-Cullin1-F-box (SCF) complex that inactivates non-self S-RNases via their polyubiquitination, which leads to degradation by 26S proteasome. In fact, PhSSK1 (Petunia hybrida SLF-interacting Skp1-like1) was identified as a specific component of SCF^SLF and was shown to be essential for detoxification of S-RNase in Petunia However, different molecules are proposed as the candidate Cullin1, another component of SCF^SLF, and there is as yet no definite conclusion. Here, we identified five Cullin1s from the expressed sequence tags (ESTs) derived from the male reproductive organ in Petunia Among them, only PhCUL1-P was co-immunoprecipitated with S₇-SLF2. In vitro protein-binding assay suggested that PhSSK1 specifically forms a complex with PhCUL1-P in an SLF-dependent manner. Knockdown of PhCUL1-P suppressed fertility of transgenic pollen in cross-compatible pollination in the functional S-RNase-dependent manner. These results suggested that SCF^SLF selectively uses PhCUL1-P. Phylogeny of Cullin1s indicates that CUL1-P is recruited into the SI machinery during the evolution of Solanaceae, suggesting that the SI components have evolved differently among species in Solanaceae and Rosaceae, despite both families sharing the S-RNase-based SI.

Mouth breathing, another risk factor for asthma: the Nagahama Study

BACKGROUND

Allergic rhinitis, a known risk factor for asthma onset, often accompanies mouth breathing. Mouth breathing may bypass the protective function of the nose and is anecdotally considered to increase asthma morbidity. However, there is no epidemiological evidence that mouth breathing is independently associated with asthma morbidity and sensitization to allergens. In this study, we aimed to clarify the association between mouth breathing and asthma morbidity and allergic/eosinophilic inflammation, while considering the effect of allergic rhinitis.

METHODS

This community-based cohort study, the Nagahama Study, contained a self-reporting questionnaire on mouth breathing and medical history, blood tests, and pulmonary function testing. We enrolled 9804 general citizens of Nagahama City in the Shiga Prefecture, Japan.

RESULTS

Mouth breathing was reported by 17% of the population and was independently associated with asthma morbidity. The odds ratio for asthma morbidity was 1.85 (95% CI, 1.27-2.62) and 2.20 (95% CI, 1.72-2.80) in subjects with mouth breathing alone and allergic rhinitis alone, which additively increased to 4.09 (95% CI, 3.01-5.52) when mouth breathing and allergic rhinitis coexisted. Mouth breathing in nonasthmatics was a risk for house dust mite sensitization, higher blood eosinophil counts, and lower pulmonary function after adjusting for allergic rhinitis.

CONCLUSION

Mouth breathing may increase asthma morbidity, potentially through increased sensitization to inhaled allergens, which highlights the risk of mouth-bypass breathing in the 'one airway, one disease' concept. The risk of mouth breathing should be well recognized in subjects with allergic rhinitis and in the general population.

Abstract P2-08-24: High levels of serum C-terminal crosslinking telopeptide of type 1 collagen at baseline are associated with poor prognosis for breast cancer patients

Background: It has been demonstrated that adjuvant treatment using bisphosphonate may reduce recurrence among breast cancer patients. However, these improved prognoses of patients are reportedly limited to breast cancers of estrogen receptor (ER)-positive and postmenopausal women. Although the mechanisms of the effects of bisphosphonate remain unknown, this finding seems to represent support for the hypothesis that suppression of bone resorption by bisphosphonate results in favorable prognoses at least for patients in this subset. In order to determine the prognostic significance of bone resorption in breast cancer patients, we investigated these markers c-terminal crosslinking telopeptide of type I collagen (1CTP) and N-telopeptide of type I collagen (NTX).

Patients and Methods: 469 breast cancer patients were recruited who were operated on Hyogo College of Medicine and histologically confirmed to have invasive carcinoma. Serum 1CTP and NTX were measured preoperatively with the two-antibody radioimmunoassay and enzyme-linked immunosorbent assay methods, respectively, and blood samples were obtained before treatment from patients who were treated with neoadjuvant chemotherapy or endocrine therapy. The area under receiver operating characteristic curves were applied and optimal cutoff values were set at 3.6ng/ml for 1CTP, and 10.55nmolBCE/L premenopausal and 14.05nmolBCE/L postmenopausal for NTX. The relationships between these bone turnover markers and various clinicopathological characteristics were evaluated with the chi square or Fisher's exact test. The log-rank test was used to compare relapse-free survival (RFS) in Kaplan-Meier plots. Associations of RFS were assessed with a Cox proportional-hazards model based on the results of univariate and multivariate analyses. Differences were considered statistically significant if p&lt;0.05.

Results: There were significantly more 1CTP-high patients among postmenopausal women and RFS of 1CTP-high patients was significantly worse than that of 1CTP-low patients (5-year RFS: 0.65 vs 0.86; p=0.0002). Similarly, NTX-high patients were significantly associated with postmenopausal status, but there was no significant association between NTX-high worse RFS (p=0.0976). Multivariate analysis of tumor size, lymph node metastasis and nuclear grade identified 1CTP (hazard ratio: 2.04, 95% confidence interval: 1.13-3.68; p=0.018) as a significant independent prognostic factor. Subset analyses of 1CTP showed that prognosis was consistently worse recognized for postmenopausal (p=0.0002), but not premenopausal (p=0.37) patients. Furthermore, prognosis for 1CTP-high patients was worse for the estrogen receptor (ER)-positive subset (p=0.0005) but not for the ER-negative subset (p=0.22).

Conclusion and discussion: High levels of serum bone resorption markers at baseline were identified as significant unfavorable prognostic factors for breast cancer patients. The prognostic significance of 1CTP seems to be prominent for postmenopausal patients with ER-positive breast cancers. These findings suggest the use of bone-modifying agents as an adjuvant therapy may be beneficial for breast cancer patients, especially for patients with high serum levels of 1CTP.

Citation Format: Imamura M, Nishimikai A, Yanai A, Miyagawa Y, Higuchi T, Ozawa H, Murase K, Takatsuka Y, Miyoshi Y. High levels of serum C-terminal crosslinking telopeptide of type 1 collagen at baseline are associated with poor prognosis for breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-24.

Abstract P6-16-01: Differences in patterns of change of bone turnover markers during treatment with bone-modifying agents of breast cancer patients with bone metastases

Background: Bone-modifying agents have demonstrated their efficacy for treatment by suppressing osteoclast function. The activity of bone-modifying agents can be monitored by means of bone resorption markers such as c-terminal crosslinking telopeptide of type I collagen (1CTP) and N-telopeptide of type I collagen (NTX) as well as bone forming marker bone-specific alkaline phosphatase (BAP). In contrast to these markers which indirectly indicate bone turnover, tartrate-resistant acid phosphatase-5b (Tracp-5b) has been established as a direct marker showing osteoclast number and activity. The aim of this study was to identify the relative significance of these bone turnover markers as indicators of treatment efficacy induced by bone-modifying agents for breast cancer patients with bone metastases.

Patients and Methods: For this study, 52 breast cancer patients with bone metastases treated with bone-modifying agents were recruited. Zoledronic acid and denosumab were administered as bone-modifying agents to 36 and 22 patients, respectively (for 6 patients, denosumab was used after zoledronic acid). Serum Tracp-5b, 1CTP, NTX and BAP were measured with, respectively, the EIA (enzyme immunoassay), RIA (two-antibody radioimmunoassay), ELISA (enzyme-linked immunosorbent assay) and CLEIA (chemiluminescent enzyme immunoassay) method. Blood samples were obtained pretreatment and 1, 3 and 6 months after treatment. Changes in these bone turnover markers were statistically analyzed with Friedman's test, and correlation between serum markers and clinicopathological factors was calculated with Mann-Whitney's test.

Results: Serum tracp-5b decreased significantly after treatment (p&lt;0.0001). The baseline median value of Tracp-5b (457.5mU/dl, range: 173-1630mU/dl) had been reduced to 137mU/dl (91-795mU/dl) 1 month after treatment, but no further reduction was observed after that. For 13 out of 15 patients to whom Tracp-5b was administered, abnormally high levels (above 420mU/dl) decreased to normal range with one month treatment. Serum NTX was also significantly reduced after treatment (p=0.0007). The median baseline value (16.5nmolBCE/L, 6.1-52.2nmolBCE/L) was diminished after 1 month (to 10.9nmolBCE/L, 7.0-49.5nmolBCE/L), and further reduction of NTX was observed after 3 months (9.55nmolBCE/L, 6.4-56.0nmolBCE/L). Similarly, baseline BAP (15.1μg/L, 6.4-81.3μg/L) decreased significantly (p=0.0032), a reduction which was obtained after 3 months (10.15μg/L, 6.1-51.7μg/L), but not after 1 month (13.0μg/L, 7.7-137.0μg/L). On the other hand, reduction in 1CTP was not significant (p=0.83).

Conclusion and discussion: Although baseline values of the bone turnover markers Tracp-5b, NTX and BAP decreased significantly after treatment with bone-modifying agents, the pattern of reduction for these three markers varied. Tracp-5b appears to reflect efficacy of bone-modifying agents most quickly and sensitively, possibly due to its direct link to the number and activity of osteoclasts. These findings may prove usefulness of Tracp-5b when considering the efficacy of various bone-modifying agents in clinical practice.

Citation Format: Higuchi T, Nishimukai A, Yanai A, Miyagawa Y, Murase K, Imamura M, Ozawa H, Takatsuka Y, Miyoshi Y. Differences in patterns of change of bone turnover markers during treatment with bone-modifying agents of breast cancer patients with bone metastases. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-16-01.

Efficient expression of SRK intracellular domain by a modeling-based protein engineering

S-locus protein kinase (SRK) is a receptor kinase that plays a critical role in self-recognition in the Brassicaceae self-incompatibility (SI) response. SRK is activated by binding of its ligand S-locus protein 11 (SP11) and subsequently induced phosphorylation of the intracellular kinase domain. However, a detailed activation mechanism of SRK is still largely unknown because of the difficulty in stably expressing SRK recombinant proteins. Here, we performed modeling-based protein engineering of the SRK kinase domain for stable expression in Escherichia coli. The engineered SRK intracellular domain was expressed about 54-fold higher production than wild type SRK, without loss of the kinase activity, suggesting it could be useful for further biochemical and structural studies.

Stromal cells expressing hedgehog-interacting protein regulate the proliferation of myeloid neoplasms

Aberrant reactivation of hedgehog (Hh) signaling has been described in a wide variety of human cancers including cancer stem cells. However, involvement of the Hh-signaling system in the bone marrow (BM) microenvironment during the development of myeloid neoplasms is unknown. In this study, we assessed the expression of Hh-related genes in primary human CD34⁺ cells, CD34⁺ blastic cells and BM stromal cells. Both Indian Hh (Ihh) and its signal transducer, smoothened (SMO), were expressed in CD34⁺ acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)-derived cells. However, Ihh expression was relatively low in BM stromal cells. Remarkably, expression of the intrinsic Hh-signaling inhibitor, human Hh-interacting protein (HHIP) in AML/MDS-derived stromal cells was markedly lower than in healthy donor-derived stromal cells. Moreover, HHIP expression levels in BM stromal cells highly correlated with their supporting activity for SMO⁺ leukemic cells. Knockdown of HHIP gene in stromal cells increased their supporting activity although control cells marginally supported SMO⁺ leukemic cell proliferation. The demethylating agent, 5-aza-2′-deoxycytidine rescued HHIP expression via demethylation of HHIP gene and reduced the leukemic cell-supporting activity of AML/MDS-derived stromal cells. This indicates that suppression of stromal HHIP could be associated with the proliferation of AML/MDS cells.

Three-dimensional patterns of early acetabular cartilage damage in hip dysplasia; a high-resolutional CT arthrography study

OBJECTIVE

The purpose of this study was to examine the three-dimensional (3D) progression patterns of early acetabular cartilage damage in hip dysplasia using high-resolutional computed tomography (CT) arthrography.

DESIGN

Thirty-two dysplastic hips of 26 Japanese symptomatic females including 21 hips in pre-stage of osteoarthritis (Kellgren-Lawrence (K-L) grade 0; mean patient age, 32.0 years) and 11 hips in early stage of osteoarthritis (K-L grade 1 or 2; mean patient age, 32.8 years) were examined. Isotropic high-resolutional CT arthrography with an image resolution of 0.5 mm in any orthogonal direction was performed. A 3D acetabular cartilage model was generated and we evaluated distribution of cartilage thickness in 12 zones after dividing the weight-bearing area of the hip joint in radial and lateral/medial directions.

RESULTS

In pre-stage of osteoarthritis, significant differences in cartilage thickness were observed between the lateral and medial zones in all radial regions, most prominently in the antero-superior region. In early stage of osteoarthritis, no significant differences in cartilage thickness were observed, except in the most posterior region. The lateral-medial (LM) ratio was defined as cartilage thickness in the lateral zone divided by that in the medial zone, and hips with the LM ratio in the antero-superior region of <1.4 had significantly more extensive involvement of labral tears than hips with the LM ratio of ≥1.4.

CONCLUSIONS

In hip dysplasia, acetabular cartilage damage was probably occurred in the antero-superior lateral area. The LM ratio may be a sensitive index to quantify early cartilage damage associated with extent of labral disorders.

Ex vivo imaging of mouse brain using micro-CT with non-ionic iodinated contrast agent: a comparison with myelin staining

OBJECTIVE

We investigated the use of micro-CT with contrast agent for the non-invasive characterisation of fixed mouse brain tissue specimens as a means to differentiate between grey and white matter.

METHODS

Nine mice were divided into two groups for micro-CT (n=6) and myelin staining (n=3) experiments. Six mice underwent in vivo micro-CT and were then prepared for brain specimens by transcardiac perfusion with paraformaldehyde. The six mouse brains were soaked in two different concentrations of non-ionic iodinated contrast agents (60 and 150 mg ml(-1)). Immersion times used for each concentration of iodine were for 3, 7 and 14 days. Three-dimensional ex vivo micro-CT images were acquired with a resolution of 39 μm(3) to create isotropic images. The other three mice were stained for evaluation of the myelin structure.

RESULTS

Soaking the brains in non-ionic iodinated contrast agent resulted in clear differences in signal between the grey matter, the white matter and the ventricular spaces. The 150 mg ml(-1) contrast agent solution yielded images with better contrast-to-noise ratio (CNR) than 60 mg ml(-1) iodine contrast agent solution. 14 days of soaking yielded images with better CNR than 3 and 7 days. The CT contrast of grey and white matter derived from the iodine-soaked fixed brains was strongly related to tissue myelin.

CONCLUSION

The present study demonstrated that micro-CT can be used to detect the mouse brain myelin structure at 3, 7 and 14 days after fixation using a CT contrast agent.

Typing of O26 enterohaemorrhagic and enteropathogenic Escherichia coli isolated from humans and cattle with IS621 multiplex PCR-based fingerprinting

AIMS

This study evaluated a typing method of O26:H11 enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) based on the variation in genomic location and copy numbers of IS621.

METHODS AND RESULTS

Two multiplex PCRs, targeting either the left (5') or right (3') IS/chromosome junction of 12 IS621 insertion sites and one PCR specific of another truncated copy, were developed. Thirty-eight amplification profiles were observed amongst a collection of 69 human and bovine O26:H11 EHEC and EPEC. Seventy-one per cent of the 45 EHEC and EPEC with identical IS621 fingerprints within groups of two, three or four isolates had >85% pulsed field gel electrophoresis (PFGE) profile similarity, including four groups of epidemiologically related EHEC or EPEC, while most of the groups had <85% similarity between each others. Epidemiologically related EHEC from each of three independent outbreaks in Japan and Belgium also exhibited identical IS621 fingerprints and PFGE profiles.

CONCLUSIONS

The IS621 fingerprinting and the PFGE are complementary typing assays of EHEC and EPEC; though, the former is less discriminatory.

SIGNIFICANCE AND IMPACT OF THE STUDY

The IS621 printing method represents a rapid (24 h) first-line surveillance and typing assay, to compare and trace back O26:H11 EHEC and EPEC during surveys in farms, multiple human cases and outbreaks.

Non-invasive ventilation in severe asthma attack, its possibilities and problems

Asthma attack is characterized by episodic attacks of cough, dyspnea and wheeze occurring due to bronchoconstriction, airway hyperresponsiveness and mucous hypersecretion. Although nationwide clinical guidelines have been published to establish the standard care of asthma, choices in the treatment of fatal asthma attacks remain of clinical significance. Especially, in a severe asthma attack, despite the application of conventional medical treatment, respiratory management is critical. Even though non-invasive ventilation (NIV) has been shown to be effective in a wide variety of clinical settings, reports of NIV in asthmatic patients are scarce. According to a few prospective clinical trials reporting promising results in favour of the use of NIV in a severe asthma attack, a trial of NIV prior to invasive mechanical ventilation seems acceptable and may benefit patients by decreasing the need for intubation and by supporting pharmaceutical treatments. Although selecting the appropriate patients for NIV use is a key factor in successful NIV application, how to distinguish such patients is quite controversial. Larger high quality clinical trails are urgently required to confirm the benefits of NIV to patients with severe asthma attack. In this article, we focus on the body of evidence supporting the use of NIV in asthma attacks and discuss its advantages as well its problems.

Experimental verification of protective effect of hydrogen-rich water against cisplatin-induced nephrotoxicity in rats using dynamic contrast-enhanced CT

Our aim was to assess the protective effect of hydrogen-rich water against cisplatin-induced nephrotoxicity in rats using dynamic contrast-enhanced CT (DCE-CT). DCE-CT studies were performed in 30 rats (8 weeks old) on days 0, 2, 4 and 7 using multidetector row CT. The rats were divided into three groups: a control group (n = 6) with free access to standard water and without cisplatin injection, a non-treatment group (n = 12) with free access to standard water and injected with cisplatin (3.6 mg kg(-1) body weight) intraperitoneally on day 0 and a treatment group (n = 12) with free access to hydrogen-rich water starting from 7 days before cisplatin injection. The contrast clearance per unit renal volume (K(1)) was estimated from the DCE-CT data using the Patlak model. The contrast clearance of the entire kidney (K) was obtained by multiplying K(1) by the renal volume. The serum creatinine level was also measured on day 7. The K(1) and K values normalised by those on day 0 in the treatment group were significantly greater than those in the non-treatment group on days 2, 4 and 7. There were no significant differences in the normalised K value between the treatment and control groups on days 2 and 7. The serum creatinine level in the treatment group was significantly lower than that in the non-treatment group and was not significantly different from that in the control group. This study demonstrated that hydrogen-rich water ameliorates renal dysfunction due to cisplatin-induced nephrotoxicity in rats.

Loading and knee alignment have significant influence on cartilage MRI T2 in porcine knee joints

OBJECTIVE

Physiological magnetic resonance imaging (MRI) under loading or knee malalignment conditions has not been thoroughly investigated. We assessed the influence of static loading and knee alignment on T2 (transverse relaxation time) mapping of the knee femoral cartilage of porcine knee joints using a non-metallic pressure device.

METHODS

Ten porcine knee joints were harvested en bloc with intact capsules and surrounding muscles and imaged using a custom-made pressure device and 3.0-T MRI system. Sagittal T2 maps were obtained (1) at knee neutral alignment without external loading (no loading), (2) under mechanical compression of 140 N (neutral loading), and (3) under the same loading conditions as in (2) with the knee at 10 degrees varus alignment (varus loading). T2 values of deep, intermediate, and superficial zones of the medial and lateral femoral cartilages at the weight-bearing area were compared among these conditions using custom-made software. Cartilage contact pressure between the femoral and tibial cartilages, measured by a pressure-sensitive film, was correlated with cartilage T2 measurements.

RESULTS

In the medial cartilage, mean T2 values of the deep, intermediate, and superficial zones decreased by 1.4%, 13.0%, and 6.0% under neutral loading. They further decreased by 4.3%, 19.3%, and 17.2% under varus loading compared to no loading. In the lateral cartilage, these mean T2 values decreased by 3.9%, 7.7%, and 4.2% under neutral loading, but increased by 1.6%, 9.6%, and 7.2% under varus loading. There was a significant decrease in T2 values in the intermediate zone of the medial cartilage under both neutral and varus loading, and in the superficial zone of the medial cartilage under varus loading (P<0.05). Total contact pressure values under neutral loading and varus loading conditions significantly correlated with T2 values in the superficial and intermediate zones of the medial cartilages.

CONCLUSIONS

The response of T2 to change in static loading or alignment varied between the medial and lateral cartilages, and among the deep, intermediate, and superficial zones. These T2 changes were significantly related to the contact pressure measurements. Our results indicate that T2 mapping under loading allows non-invasive, biomechanical assessment of site-specific stress distribution in the cartilage.

Gibberellin-induced DELLA recognition by the gibberellin receptor GID1

Gibberellins control a range of growth and developmental processes in higher plants and have been widely used in the agricultural industry. By binding to a nuclear receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1), gibberellins regulate gene expression by promoting degradation of the transcriptional regulator DELLA proteins, including GIBBERELLIN INSENSITIVE (GAI). The precise manner in which GID1 discriminates and becomes activated by bioactive gibberellins for specific binding to DELLA proteins remains unclear. Here we present the crystal structure of a ternary complex of Arabidopsis thaliana GID1A, a bioactive gibberellin and the amino-terminal DELLA domain of GAI. In this complex, GID1A occludes gibberellin in a deep binding pocket covered by its N-terminal helical switch region, which in turn interacts with the DELLA domain containing DELLA, VHYNP and LExLE motifs. Our results establish a structural model of a plant hormone receptor that is distinct from the mechanism of the hormone perception and effector recognition of the known auxin receptors.

Proteolysis-independent downregulation of DELLA repression in Arabidopsis by the gibberellin receptor GIBBERELLIN INSENSITIVE DWARF1

This article presents evidence that DELLA repression of gibberellin (GA) signaling is relieved both by proteolysis-dependent and -independent pathways in Arabidopsis thaliana. DELLA proteins are negative regulators of GA responses, including seed germination, stem elongation, and fertility. GA stimulates GA responses by causing DELLA repressor degradation via the ubiquitin-proteasome pathway. DELLA degradation requires GA biosynthesis, three functionally redundant GA receptors GIBBERELLIN INSENSITIVE DWARF1 (GID1a, b, and c), and the SLEEPY1 (SLY1) F-box subunit of an SCF E3 ubiquitin ligase. The sly1 mutants accumulate more DELLA proteins but display less severe dwarf and germination phenotypes than the GA biosynthesis mutant ga1-3 or the gid1abc triple mutant. Interestingly, GID1 overexpression rescued the sly1 dwarf and infertility phenotypes without decreasing the accumulation of the DELLA protein REPRESSOR OF ga1-3. GID1 rescue of sly1 mutants was dependent on the level of GID1 protein, GA, and the presence of a functional DELLA motif. Since DELLA shows increasing interaction with GID1 with increasing GA levels, it appears that GA-bound GID1 can block DELLA repressor activity by direct protein-protein interaction with the DELLA domain. Thus, a SLY1-independent mechanism for GA signaling may function without DELLA degradation.

A quantitative method for estimating hepatic blood flow using a dual-input single-compartment model

The purpose of this study was to investigate the accuracy of a quantitative method for estimating arterial hepatic blood flow and portal hepatic blood flow separately using a dual-input single-compartment model compared with the maximum slope method using computer simulations and clinical data. In computer simulations, the rate constants for the transfer of contrast agent (CA) from the hepatic artery to the liver (K(1a)), from the portal vein to the liver (K(1p)) and from the liver to the blood (k(2)) were estimated from simulated time-density curves with various transit times of CA from the aorta to the liver (tau(a)) and from the portal vein to the liver (tau(p)) using the linear least-squares (LLSQ) method. In clinical studies, dynamic CT data were acquired from 27 patients, and parametric maps of K(1a), K(1p) and k(2) were generated by applying the LLSQ method pixel by pixel. In simulation studies, tau(a) and tau(p) were found to have a large and a small effect on the estimates of K(1a) and K(1p), respectively. In clinical studies, the K(1a) and K(1p) values estimated with the maximum slope method were underestimated by 60+/-29% and 37+/-12%, respectively, compared with those estimated by the LLSQ method. In conclusion, our results suggest that correction of tau(a) is necessary for accurately estimating K(1a) and K(1p). Our method is therefore promising for the evaluation of hepatic blood flow in various liver diseases because it allows us to evaluate arterial hepatic blood flow and portal hepatic blood flow separately and visually.

Two distinct forms of M-locus protein kinase localize to the plasma membrane and interact directly with S-locus receptor kinase to transduce self-incompatibility signaling in Brassica rapa

Many flowering plants possess systems of self-incompatibility (SI) to prevent inbreeding. In Brassica, SI recognition is controlled by the multiallelic gene complex (S-haplotypes) at the S-locus, which encodes both the male determinant S-locus protein 11 (SP11/SCR) and the female determinant S-receptor kinase (SRK). Upon self-pollination, the S-haplotype-specific interaction between the pollen-borne SP11 and the cognate stigmatic SRK receptor induces SI signaling in the stigmatic papilla cell and results in rejection of the self-pollen. Our genetic analysis of a self-compatible mutant revealed the involvement of a cytoplasmic protein kinase, M-locus protein kinase (MLPK), in the SI signaling, but its exact physiological function remains unknown. In this study, we identified two different MLPK transcripts, MLPKf1 and MLPKf2, which are produced using alternative transcriptional initiation sites and encode two isoforms that differ only at the N termini. While MLPKf1 and MLPKf2 exhibited distinct expression profiles, both were expressed in papilla cells. MLPKf1 localizes to the plasma membrane through its N-terminal myristoylation motif, while MLPKf2 localizes to the plasma membrane through its N-terminal hydrophobic region. Although both MLPKf1 and MLPKf2 could independently complement the mlpk/mlpk mutation, their mutant forms that lack the plasma membrane localization motifs failed to complement the mutation. Furthermore, a bimolecular fluorescence complementation assay revealed direct interactions between SRK and the MLPK isoforms in planta. These results suggest that MLPK isoforms localize to the papilla cell membrane and interact directly with SRK to transduce SI signaling.

Global analysis of della direct targets in early gibberellin signaling in Arabidopsis

Bioactive gibberellins (GAs) are phytohormones that regulate growth and development throughout the life cycle of plants. DELLA proteins are conserved growth repressors that modulate all aspects of GA responses. These GA-signaling repressors are nuclear localized and likely function as transcriptional regulators. Recent studies demonstrated that GA, upon binding to its receptor, derepresses its signaling pathway by binding directly to DELLA proteins and targeting them for rapid degradation via the ubiquitin-proteasome pathway. Therefore, elucidating the signaling events immediately downstream of DELLA is key to our understanding of how GA controls plant development. Two sets of microarray studies followed by quantitative RT-PCR analysis allowed us to identify 14 early GA-responsive genes that are also early DELLA-responsive in Arabidopsis thaliana seedlings. Chromatin immunoprecipitation provided evidence for in vivo association of DELLA with promoters of eight of these putative DELLA target genes. Expression of all 14 genes was downregulated by GA and upregulated by DELLA. Our study reveals that DELLA proteins play two important roles in GA signaling: (1) they help establish GA homeostasis by direct feedback regulation on the expression of GA biosynthetic and GA receptor genes, and (2) they promote the expression of downstream negative components that are putative transcription factors/regulators or ubiquitin E2/E3 enzymes. In addition, one of the putative DELLA targets, XERICO, promotes accumulation of abscisic acid (ABA) that antagonizes GA effects. Therefore, DELLA may restrict GA-promoted processes by modulating both GA and ABA pathways.

Global analysis of della direct targets in early gibberellin signaling in Arabidopsis

Bioactive gibberellins (GAs) are phytohormones that regulate growth and development throughout the life cycle of plants. DELLA proteins are conserved growth repressors that modulate all aspects of GA responses. These GA-signaling repressors are nuclear localized and likely function as transcriptional regulators. Recent studies demonstrated that GA, upon binding to its receptor, derepresses its signaling pathway by binding directly to DELLA proteins and targeting them for rapid degradation via the ubiquitin-proteasome pathway. Therefore, elucidating the signaling events immediately downstream of DELLA is key to our understanding of how GA controls plant development. Two sets of microarray studies followed by quantitative RT-PCR analysis allowed us to identify 14 early GA-responsive genes that are also early DELLA-responsive in Arabidopsis thaliana seedlings. Chromatin immunoprecipitation provided evidence for in vivo association of DELLA with promoters of eight of these putative DELLA target genes. Expression of all 14 genes was downregulated by GA and upregulated by DELLA. Our study reveals that DELLA proteins play two important roles in GA signaling: (1) they help establish GA homeostasis by direct feedback regulation on the expression of GA biosynthetic and GA receptor genes, and (2) they promote the expression of downstream negative components that are putative transcription factors/regulators or ubiquitin E2/E3 enzymes. In addition, one of the putative DELLA targets, XERICO, promotes accumulation of abscisic acid (ABA) that antagonizes GA effects. Therefore, DELLA may restrict GA-promoted processes by modulating both GA and ABA pathways.

An efficient method for calculating kinetic parameters in a dual-input single-compartment model

Quantitative measurement of hepatic perfusion has the potential to provide important information in the assessment and management of various liver diseases. The utility of hepatic perfusion characterization relies on the resolution of each component of its dual blood supply, i.e. the hepatic artery and portal vein. In this study, a linear equation was derived by integrating the differential equation describing the kinetic behaviour of contrast agent (CA) in a dual-input single-compartment model, from which the kinetic parameters can be easily obtained using the linear least-squares method. The usefulness of this method was investigated using computer simulations, in comparison with the non-linear least-squares (NLSQ) method. This method calculated the kinetic parameters faster than the NLSQ method by a factor of approximately 10, with almost the same accuracy as the NLSQ method. This method will be useful for analysing the kinetic behaviour of CA in the unique liver environment, especially by generating the functional images of kinetic parameters.

Promotion of medial collateral ligament healing using a high-voltage electrical field

PURPOSE

To assess the biomechanical and histological effects of a high-voltage electrical field on ligament healing.

METHODS

54 male Wistar rats were used. The medial collateral ligaments (MCLs) of 6 rats were measured for normal biomechanical failure load and stiffness. MCLs of the remaining 48 rats were transected and randomly assigned; half were subjected to a high-voltage electrical field for 8 hours a day (experimental group), and the other half were kept under normal conditions (control group). Eight rats from each group were killed 2, 4, and 6 weeks after the transection and their MCLs were tested biomechanically and histologically.

RESULTS

Failure load and stiffness of the MCLs in the experimental group were significantly higher than those in the control group 2 weeks after transection, but not thereafter. At week 2, the granulation tissue completely occupied the space between the cut ends of the MCL in the experimental group, whereas some gaps remained in the control group.

CONCLUSION

A high-voltage electrical field appear to accelerate ligament healing in the initial 2 weeks. Earlier initial healing may allow earlier start of the rehabilitation.

Genetic characterization and functional analysis of the GID1 gibberellin receptors in Arabidopsis

We investigated the physiological function of three Arabidopsis thaliana homologs of the gibberellin (GA) receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) by determining the developmental consequences of GID1 inactivation in insertion mutants. Although single mutants developed normally, gid1a gid1c and gid1a gid1b displayed reduced stem height and lower male fertility, respectively, indicating some functional specificity. The triple mutant displayed a dwarf phenotype more severe than that of the extreme GA-deficient mutant ga1-3. Flower formation occurred in long days but was delayed, with severe defects in floral organ development. The triple mutant did not respond to applied GA. All three GID1 homologs were expressed in most tissues throughout development but differed in expression level. GA treatment reduced transcript abundance for all three GID1 genes, suggesting feedback regulation. The DELLA protein REPRESSOR OF ga1-3 (RGA) accumulated in the triple mutant, whose phenotype could be partially rescued by loss of RGA function. Yeast two-hybrid and in vitro pull-down assays confirmed that GA enhances the interaction between GID1 and DELLA proteins. In addition, the N-terminal sequence containing the DELLA domain is necessary for GID1 binding. Furthermore, yeast three-hybrid assays showed that the GA-GID1 complex promotes the interaction between RGA and the F-box protein SLY1, a component of the SCF(SLY1) E3 ubiquitin ligase that targets the DELLA protein for degradation.

Relationship between variations in the circle of Willis and flow rates in internal carotid and basilar arteries determined by means of magnetic resonance imaging with semiautomated lumen segmentation: reference data from 125 healthy volunteers

BACKGROUND AND PURPOSE

Volume flow rates in the feeding arteries of the brain are measured to evaluate blood flow dynamics in vascular disease. Although these flow values are thought to be effected by anatomic variations in the circle of Willis, few reports have described the effect. This study reports on the relationship between variations in the circle of Willis and volume flow rates in the bilateral internal carotid and basilar arteries of normal volunteers.

METHODS

We prospectively examined 125 healthy volunteers by MR imaging. Variations in the circle of Willis were classified as "textbook" type, hypoplasia of the precommunicating segment of the anterior cerebral artery (A1), hypoplasia of the precommunicating segment of the posterior cerebral artery (P1), or "other." Volume flow rates were measured by 2D cine phase-contrast MR imaging. Lumen boundaries and volume flow rates were semiautomatically determined by pulsatility-based segmentation.

RESULTS

Of the 117 subjects (61 men, 56 women; mean age, 23.6 years) considered suitable for flow measurement, 105 showed textbook type, and 6 each showed A1 hypoplasia and P1 hypoplasia. Total flow rates for the 3 variations were 781 +/- 151 mL/min (mean +/- SD), 744 +/- 119, and 763 +/- 129, respectively. Relative contributions by flow rates of the internal carotid arteries and the basilar artery for the 3 variations were 39.8%:38.9%:21.3%, 31.8%:49.1%:19.0%, and 46.6%:41.6%:11.7%, respectively, showing statistically significant differences.

CONCLUSIONS

Variations in the circle of Willis correlate significantly with relative contributions by the flow rates of the bilateral internal carotid and basilar arteries.

Composite Hypo-Hyper-d-Intermetallic and Interionic Phases as Supported Interactive Electrocatalysts

Interactive, strong interbonding and highly electron conductive nonstoichiometric titanium suboxide catalytic supports, Magneli phases (Ti(n)O(2n-1), on average Ti(4)O(7)), have been used in the electrocatalysis of hydrogen (HELR) and oxygen (OELR) electrode reactions with remarkable consequences and advanced achievements. The theory of hypo-hyper-d-interelectronic bonding of transition metal ions and atoms has been employed for selective ordered grafting and shown to stay in the core of the strong metal-support interaction (SMSI) in heterogeneous catalysis and electrocatalysis, and thereby the substantial cause for the improved synergistic activity of composite (electro)catalysts. The same fundament has been the thermodynamic basis for the thermal production of symmetric intermetallic Laves type phases of nanostructured electrocatalysts, in particular the ones with higher oxophilic properties of hypo-d-elements. Remarkably advanced in electrocatalytic activity, highly monatomically dispersed deposits of Pt upon Magneli phases are shown to be unique and highly promising electrocatalysts for the cathodic oxygen reduction (ORR). Nanostructured Au upon a thin nanocrystalline film of anatase titania has been confirmed by X-ray photoelectron spectroscopy (XPS) as a typical classical paradigm of the SMSI, and at the same time affording the basis for gold with strained d-orbitals, as the reversible hydrogen electrode. Magneli phases have been shown to be the best electrocatalytic supports with unique properties both for low temperature PEM fuel cells (LT PEM FCs) with pronounced CO tolerance and water electrolysis in membrane type hydrogen generators.

Comparison of patient doses in 256-slice CT and 16-slice CT scanners

The 256-slice CT-scanner has been developed at the National Institute of Radiological Sciences. Nominal beam width was 128 mm in the longitudinal direction. When scanning continuously at the same position to obtain four-dimensional (4D) images, the effective dose is increased in proportion to the scan time. Our purpose in this work was to measure the dose for the 256-slice CT, to compare it with that of the 16-slice CT-scanner, and to make a preliminary assessment of dose for dynamic 3D imaging (volumetric cine imaging). Our group reported previously that the phantom length and integration range for dosimetry needed to be at least 300 mm to represent more than 90% of the line integral dose with the beam width between 20 mm and 138 mm. In order to obtain good estimates of the dose, we measured the line-integral dose over a 300 mm range in PMMA (polymethylmethacrylate) phantoms of 160 mm or 320 mm diameter and 300 mm length. Doses for both CT systems were compared for a clinical protocol. The results showed that the 256-slice CT generates a smaller dose than the 16-slice CT in all examinations. For volumetric cine imaging, we found an acceptable scan time would be 6 s to 11 s, depending on examinations, if dose must be limited to the same values as routine examinations with a conventional multidetector CT. Finally, we discussed the studies necessary to make full use of volumetric cine imaging.

Cloning and sequencing of a chitinase gene from Vibrio alginolyticus H-8

A gene from Vibrio alginolyticus H-8, encoding chitinase, designated as chitinase B, was cloned by the shot-gun method using pUC118 and sequenced. The open reading frame consisted of 846 amino acids including a signal peptide. The molecular mass of the enzyme estimated based on the amino acid sequence data was 90 kDa. The N-terminal amino acid sequence of the enzyme was different from that of chitinase C1 which we had previously reported. This cloned chitinase B was considered one out of four chitinases (A, B, D, and E) which had been newly isolated from the culture broth and cell extract of V. alginolyticus H-8. The gene contained a chitin-binding domain and typical conserved regions of chitinases reported previously. The deduced amino acid sequence of the cloned chitinase B showed high sequence homology with the chitinase from V. parahaemolyticus (84% identity) and the chitinase from V. anguillarum (76.6%), but low sequence homology with the chitinase from V. harveyi (24.4%), and the chitodextrinase from V. furnissii (23.9%). Chitinase E found in cell extract is considered an intracellular chitinase which is different from chitodextrinases.