DPSCs regulate epithelial-T cell interactions in oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSF) is a precancerous lesion characterized by fibrous tissue deposition, the incidence of which correlates positively with the frequency of betel nut chewing. Prolonged betel nut chewing can damage the integrity of the oral mucosal epithelium, leading to chronic inflammation and local immunological derangement. However, currently, the underlying cellular events driving fibrogenesis and dysfunction are incompletely understood, such that OSF has few treatment options with limited therapeutic effectiveness. Dental pulp stem cells (DPSCs) have been recognized for their anti-inflammatory and anti-fibrosis capabilities, making them promising candidates to treat a range of immune, inflammatory, and fibrotic diseases. However, the application of DPSCs in OSF is inconclusive. Therefore, this study aimed to explore the pathogenic mechanism of OSF and, based on this, to explore new treatment options.

METHODS

A human cell atlas of oral mucosal tissues was compiled using single-cell RNA sequencing to delve into the underlying mechanisms. Epithelial cells were reclustered to observe the heterogeneity of OSF epithelial cells and their communication with immune cells. The results were validated in vitro, in clinicopathological sections, and in animal models. In vivo, the therapeutic effect and mechanism of DPSCs were characterized by histological staining, immunohistochemical staining, scanning electron microscopy, and atomic force microscopy.

RESULTS

A unique epithelial cell population, Epi1.2, with proinflammatory and profibrotic functions, was predominantly found in OSF. Epi1.2 cells also induced the fibrotic process in fibroblasts by interacting with T cells through receptor-ligand crosstalk between macrophage migration inhibitory factor (MIF)-CD74 and C-X-C motif chemokine receptor 4 (CXCR4). Furthermore, we developed OSF animal models and simulated the clinical local injection process in the rat buccal mucosa using DPSCs to assess their therapeutic impact and mechanism. In the OSF rat model, DPSCs demonstrated superior therapeutic effects compared with the positive control (glucocorticoids), including reducing collagen deposition and promoting blood vessel regeneration. DPSCs mediated immune homeostasis primarily by regulating the numbers of KRT19 + MIF + epithelial cells and via epithelial-stromal crosstalk.

CONCLUSIONS

Given the current ambiguity surrounding the cause of OSF and the limited treatment options available, our study reveals that epithelial cells and their crosstalk with T cells play an important role in the mechanism of OSF and suggests the therapeutic promise of DPSCs.

The role of the social environment on dementia caregivers' pre-death grief: A mixed- methods systematic review

This systematic review examined the role of social environment in pre-death grief experiences of dementia caregivers. Ninety-three Chinese and English articles were included from a comprehensive search of empirical studies using nine databases. Six social environment domains were generated: the person with dementia, dyadic relationship, family members and the wider community, health and social care services, place of care, and social-cultural contexts. A complex interplay between caregivers and their social environments that aggravate and attenuate pre-death grief experiences is evident. Research has focused mainly on the effects of people with dementia and dyadic relationships and has paid modest attention to the effects of family, relatives, and health and social care services. Caregivers' experiences with their friends, fellow caregivers, the wider community, and social-cultural norms are influential but understudied. Future research could adopt a systems thinking approach with sociological perspectives to generate a comprehensive and nuanced understanding of pre-death grief experiences.

From i-coping to we-coping: A retrospective qualitative study on parent-child dyadic coping in widowed families

In a widowed family, the surviving parent and children face the loss together. However, most previous research in bereavement has focused on individual experiences. Although the family perspective has been introduced into the field, neither theories nor empirical research has explored mutual interaction. Dyadic coping reflects the family perspective and has been proven to be an influential factor in couples facing life adversities. Nevertheless, it has not been explored in the context of bereavement-specific stressors, including loss- and restoration-related stressors, nor in the parent-child relationship. This research is the first exploration of parent-child dyadic coping in widowed families in the bereavement context and aims to form a comprehensive conceptualization of parent-child dyadic coping following bereavement. Qualitative semistructured interviews were conducted with 20 parents and children from widowed families in mainland China (11 surviving children and nine widowed parents, representing 19 families). Constructivist grounded theory was used to guide the analysis. The main themes identified were dyadic coping-related cognitions, loss-oriented dyadic coping, restoration-oriented dyadic coping, and contextual factors. Three foci (thou, we, and I) were identified for both loss- and restoration-oriented dyadic coping. A conceptualization model of bereavement dyadic coping within widowed families was developed. This study extends the single I-coping perspective in bereavement coping to a we-coping perspective, provides an interactional- and operational-level knowledge on dual-process coping, acknowledges the bilateral interaction in parent-child relationships, and offers implications for bereavement support practice for widowed families. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Latent class analysis of grief-related beliefs among recently bereaved adults

Grief-related beliefs play an important role in bereavement adjustment. This study aimed to investigate the patterns and correlates of grief-related beliefs among recently bereaved adults (n = 311). Latent class analysis results suggested three meaningful grief belief classes could be identified: the High grief belief class (24.1%), Predominantly counterfactual thoughts class (42.4%), and Low belief class (33.4%). Members in the High grief belief class reported the highest levels of grief symptoms, depression and PTSD symptoms, loneliness, and functional impairment. Compared with the Low belief class, unmarried people, people in poor health, individuals who lost parents, partners, or children, and those who experienced violent or unexpected death were more likely to belong to the High grief belief class. Findings of this study support the importance of examining grief-related cognitions in research and clinical practice, especially counterfactual thoughts about the death, which may need to be specifically screened and targeted in treatment.

Redefining caregiver strain for family caregivers in end-of-life care in Hong Kong

OBJECTIVES

Caregiving for family members at their end of life is stressful. Caregivers' strain, burden, or stress has been measured in various geographical and sociodemographic contexts. The concept of stress, burden, and strain are sometimes used interchangeably. By analysing the factor structure of the Chinese version of the Modified Caregiver Strain Index (C-M-CSI), this study aimed to examine the caregiving strain concept and its demographic correlates.

METHODS

A sample of 453 family caregivers of patients with a terminal illness in Hong Kong was employed. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed. In addition, generalized linear models (GLM) were used to examine the demographic correlates.

RESULTS

The EFA yielded a 3-factor model termed "Perception of Caregiving," "Empathetic Strain," and "Adjustment Demand." This 3-factor model explained 50% of the variance and showed good internal consistency. The CFA confirmed the 3-factor construct with satisfactory internal reliability (χ² [61, N = 226] = 108.86, p < 0.001, CFI = 0.96, TLI = 0.95, SRMR = 0.04, and RMSEA = 0.06). Inspired by this factor structure and concepts of stress and strain from engineering discipline, a new model of caregiver strain is proposed. Additionally, family caregivers of non-cancer patients, who were not living with the patient, or younger were associated negatively with different dimensions of caregiver strain.

SIGNIFICANCE OF RESULTS

The results gave insights into the advancement of the conceptualization of caregiver strain, its multidimensional nature, and process of change, which inform directions for future research and practices.

The connections of physical and psychosocial symptoms among patients with terminal illnesses: A network analysis

BACKGROUND

Patients with terminal illnesses have different symptoms. The goal of palliative care is to alleviate the suffering induced by these symptoms. Available research on symptoms has focused on their prevalence or identification of clusters. Little is known about the central symptoms contributing to the maintenance of the whole system of symptoms or the mechanism of influence between symptoms, particularly between physical and psychosocial symptoms.

AIM

The study used network analysis to explore symptom clusters among patients with terminal illnesses and identify the central symptoms, the bridge symptoms, and pathways between physical and psychosocial symptoms.

DESIGN AND SETTING/PARTICIPANTS

This is a retrospective cohort study using baseline symptom assessment of 677 adults with terminal illnesses receiving care from the Integrated Community End-of-Life Care Support Teams.

RESULTS

Three symptom clusters were identified: physical, psychological, and practical clusters. "Weakness or lack of energy" was identified as the crucial symptom affecting the changes of other symptoms, followed by depression and anxiety. Three connections between the psychological and physical symptoms were identified: anxiety-pain, depression-constipation, and perceived family anxiety-poor appetite pathways. Pathways of practical concern-peace and practical concern-depression were indicated between practical and psychological symptoms.

CONCLUSIONS

This study is the first of its kind to investigate the connections and mechanism of influence between symptoms among patients with terminal illnesses. It offers clear pathways for intervention with the most influential symptoms of weakness, anxiety, and depression.

Growing in Suffering: The Curvilinear Relationship Between Prolonged Grief and Post-traumatic Growth of Recently Bereaved Individual During the COVID-19 Pandemic

The outbreak of the COVID-19 pandemic brought new challenges to mourning and growth of bereaved. The purpose is to explore the relationship between the prolonged grief (PG) symptoms and the post-traumatic growth (PTG) of recently bereaved people during the COVID-19 period, and the mediating role of meaning making. 305 participants were recruited to complete the Posttraumatic Growth Inventory, Inventory of Complicated Grief, and Integration of Stressful Life Experiences Scale. Hierarchical multiple regression analyses and Medcurve in SPSS were adapted to test the hypotheses. The results revealed that there was a curvilinear relationship between PG and PTG and meaning making had a completely mediating effect on this relationship. Different intervention goals - whether alleviating distress or cultivating growth - should be set up according to the level of grief for recently bereaved individuals during COVID-19. More attention should be paid to the role of meaning making in the future clinical practice.

Potential risk factors for acute grief during the COVID-19 pandemic: The mediating role of avoidance processes

Bereavement during the COVID-19 pandemic may have some unique characteristics that become potential risk factors (e.g., absence of grief rituals, no opportunity to say goodbye to the deceased and loneliness caused by social distancing) for acute grief. Avoidance processes could be significant mediators in the context of the pandemic. The current study aimed to investigate whether and how these COVID-19-related risk factors were related to acute grief severity. Bereaved adults (n = 319) who lost significant others during the COVID-19 pandemic completed a self-report questionnaire package measuring COVID-19-related factors, grief severity and depressive and anxious avoidance. Regression analyses suggested that among the three potential risk factors (loneliness, grief rituals and opportunity to say goodbye), loneliness was significantly associated with acute grief after controlling for basic demographic and loss-related information. Structural equation models suggested that depressive avoidance and anxious avoidance partially mediated the associations of loneliness with acute grief severity. The findings indicate that dealing with loss during the COVID-19 pandemic warrants further exploration concerning how potential environmental risk factors may impede adaptation to loss. Depressive and anxious avoidance processes may play important roles in grief interventions for isolated and lonely bereaved people.

The meaning of patient deaths for professional caregivers: A quantitative construct validation

The meaning of patient deaths is key to understanding professional bereavement. To validate its construct, we applied partial least square structural equation modeling (PLS-SEM) to online survey data from 563 Chinese physicians and nurses. Both the personal meaning and professional meaning contribute significantly while not interchangeably to the meaning of patient deaths. In addition to the loss of an acquaintance, the loss of a valuable life, and the loss of a professional goal, patient deaths can also mean trauma, bad luck, identity crisis, a warning, a learning opportunity, and a time to empathize with others' sufferings.

Fear of contamination, perceived social support and physical health of health social workers in Hong Kong: A cross-sectional survey

Hong Kong experienced the SARS pandemic in 2003. Seventeen years later, the Covid-19 pandemic now challenges Hong Kong and the world. This study aims to unveil the impact of the pandemic on health social workers. One hundred and sixty-six health care social workers in Hong Kong were recruited to join a cross-sectional online survey from November 2020 to March 2021. This paper includes the analysis of the demographic information, fear of contamination, resilience, perceived social support and physical health only. Irrespective of the demographic background, the level of fear of contamination, resilience, perceived social support and physical health were similar. The mean scores of the two dimensions of fear of contamination (Harm avoidance: m = 7.49, s.d. = 3.25; Disgust avoidance: m = 7.75, s.d. = 2.90) were higher than those of general public and clinical samples with Obsessive-Compulsive Disorder. No moderation effects were found in resilience and perceived social support in the relationship of fear of contamination and physical health. Instead, direct effects were shown.The impact of the pandemic on health social workers was universal. Psychoeducational programs to alleviate the fear of contamination and organizational-level interventions to improve workplace social support are highly needed.

Dyadic Relationships between a Surviving Parent and Children in Widowed Families: A Systematic Scoping Review

The death of a family member affects not only individual family members but also their relationships and interactions. Grief has been studied mostly as an intrapersonal experience. Adopting the family perspective, this systematic scoping review focused on parent-child relationships in widowed families so as to identify what is already known on this topic and the research gaps for future study. The review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Four databases (Web of Science, Psycinfo, PubMed, and CINAHL Plus) were searched. Search terms were combinations of two concepts: (1) loss of a parent (20 terms) and (2) parent-child (eight terms). 5,419 studies were identified during the search, of which 36 studies were included in the review following two rounds of screening. Four research themes emerged, and the aggregated findings were identified: (a) The surviving parent and children are likely to become closer following the loss of a parent, while other relevant factors need to be taken into account; (b) Better parent-child relationships play a protective role in children's adjustment to loss; (c) The surviving parent and children's adjustment to loss are interdependent; (d) Through parenting, communication style, coping strategy, and other attributes, the surviving parent can influence their children's adjustment. Gender and age differences were identified in parent-child relationships. The findings further justify the importance of a family perspective when conducting research and practice on bereavement. Several research gaps were identified. Existing studies paid insufficient attention to children's agency and bidirectional relationships, and the interaction process and its role underlying parent-child bidirectional causality. A conceptual framework of parent-child relationships in widowed families is proposed based on these findings.

Factors facilitating positive outcomes in community-based end-of-life care: A cross-sectional qualitative study of patients and family caregivers

BACKGROUND

Delivery of community-based end-of-life care for patients and family members has been recognized as an important public health care approach. Despite differences in different healthcare settings and the significance of a person-centered approach, little research has investigated facilitators of community-based end-of-life care from the perspective of service recipients. In particular, there has been limited exploration of strategies to ensure positive outcomes at an operational level.

AIM

To explore factors facilitating positive end-of-life care provision in community-based settings and how these are achieved in practice, from the perspectives of patients and family caregivers.

DESIGN

A qualitative cross-sectional descriptive study was undertaken through semi-structured interviews with patients and family caregivers subjected to thematic analysis.

SETTING/PARTICIPANTS

Ten patients and 16 family caregivers were recruited from an end-of-life community care program provided by four non-governmental organizations in Hong Kong.

RESULTS

Seven core themes were identified: positive emotions about the relationship, positive appraisals of the relationship, care through inquiring about recipients' circumstances, instrumentality of care (i.e. information, coaching on care, practical help, psychological support, multiple activities), comprehensiveness of care (i.e. diversity, post-death care, family-level wellbeing), structure of care (i.e. timely follow-up, well-developed system), and qualities of workers.

CONCLUSIONS

Improvement in service quality might be achieved through alternating the perceptions or emotional reactions of care recipients toward care providers and increased use of sensitive inquiry. Comprehensive care and positive outcomes might be facilitated by addressing the dualities of care by providing diverse choices in pre-death and post-death care.

MicroRNA-29b Promotes Subchondral Bone Loss in TMJ Osteoarthritis

Abnormal subchondral bone remodeling plays important roles during osteoarthritis (OA) pathology. Recent studies show that bone marrow mesenchymal stem cells (BMSCs) in osteoarthritic subchondral bones exhibit a prominent pro-osteoclastic effect that contributes to abnormal subchondral bone remodeling; however, the pathologic mechanism remains unclear. In the present study, we used a mouse model with OA-like change in the temporomandibular joint (TMJ) induced by an experimentally unilateral anterior crossbite (UAC) and found that the level of microRNA-29b (miR-29b), but not miR-29a or miR-29c, was markedly lower in BMSCs from subchondral bones of UAC mice as compared with that from the sham control mice. With an intra-articular aptamer delivery system, BMSC-specific overexpression of miR-29b by aptamer-agomiR-29b rescued subchondral bone loss and osteoclast hyperfunction in UAC mice, as demonstrated by a significant increase in bone mineral density, bone volume fraction, trabecular thickness, and the gene expression of osteocalcin and Runx2 but decreased trabecular separation, osteoclast number and osteoclast surface/bone surface, and the gene expression of cathepsin K, Trap, Wnt5a, Rankl, and Rank as compared with those in the UAC mice treated by aptamer-NC (all P < 0.05). In addition, BMSC-specific inhibition of miR-29b by aptamer-antagomiR-29b exacerbated those responses in UAC mice. Notably, although it primarily affected miR-29b levels in the subchondral bone (but not in cartilage and synovium), BMSC-specific overexpression of miR-29b in UAC mice largely rescued OA-like cartilage degradation, including decreased chondrocyte density, cartilage thickness, and the percentage areas of proteoglycans and type II collagen, while BMSC-specific inhibition of miR-29b aggravated these characteristics of cartilage degradation in UAC mice. Moreover, we identified Wnt5a, but not Rankl or Sdf-1, as the direct target of miR-29b. The results of the present study indicate that miR-29b is a key regulator of the pro-osteoclastic effects of BMSCs in TMJ-OA subchondral bones and plays important roles in the TMJ-OA progression.

SYMMETRIC PETALS 1 Encodes an ALOG Domain Protein that Controls Floral Organ Internal Asymmetry in Pea (Pisum sativum L.)

In contrast to typical radially symmetrical flowers, zygomorphic flowers, such as those produced by pea (Pisum sativum L.), have bilateral symmetry, manifesting dorsoventral (DV) and organ internal (IN) asymmetry. However, the molecular mechanism controlling IN asymmetry remains largely unclear. Here, we used a comparative mapping approach to clone SYMMETRIC PETALS 1 (SYP1), which encodes a key regulator of floral organ internal asymmetry. Phylogenetic analysis showed that SYP1 is an ortholog of Arabidopsis thaliana LIGHT-DEPENDENT SHORT HYPOCOTYL 3 (LSH3), an ALOG (Arabidopsis LSH1 and Oryza G1) family transcription factor. Genetic analysis and physical interaction assays showed that COCHLEATA (COCH, Arabidopsis BLADE-ON-PETIOLE ortholog), a known regulator of compound leaf and nodule identity in pea, is involved in organ internal asymmetry and interacts with SYP1. COCH and SYP1 had similar expression patterns and COCH and SYP1 target to the nucleus. Furthermore, our results suggested that COCH represses the 26S proteasome-mediated degradation of SYP1 and regulates its abundance. Our study suggested that the COCH-SYP1 module plays a pivotal role in floral organ internal asymmetry development in legumes.

MiR-378a-5p inhibits angiogenesis of oral squamous cell carcinoma by targeting KLK4

Oral squamous cell carcinoma (OSCC) is still a leading cause of cancer death owing to distant metastasis, which is largely facilitated by tumor angiogenesis. MicroRNA (miR)-378a-5p and Kallikrein-related peptidase 4 (KLK4) participate in tumorigenesis and tumor metastasis according to previous studies, yet the exact role they play in tumor angiogenesis remains poorly understood. The aim of the present study is to investigate the effect of miR-378a-5p and KLK4 on angiogenesis of OSCC. MTT assay showed that the expression level of miR-378a-5p was negatively correlated with the proliferation of OSCC cells. ELISA and Western blot assay showed that down-regulation of miR-378a-5p promotes VEGF expression. Tube formation and in vivo chicken chorioallantoic membrane (CAM) assay showed that inhibition of miR-378a-5p reduced tube formation of human umbilical vein endothelial cells (HUVECs) and newly formed microvessel. On the contrary, over-expression of KLK4 enhanced angiogenesis of OSCC cells with increased VEGF expression, tube formation activity of HUVECs and newly formed microvessel. Moreover, the dual-luciferase assay validated that KLK4 was a target gene of miR-378a-5p. MiR-378a-5p silencing induced tube formation was suppressed by the downregulation of KLK4. Besides, the activation of Wnt/β-catenin signaling pathway in miR-378a-5p antagomir transfected cells was also blocked by the KLK4 shRNA. To sum up, our study suggests that miR-378a-5p suppressed angiogenesis of OSCC at least partly by the regulation of KLK4.

Love on wings, a Dof family protein regulates floral vasculature in Vigna radiata

BACKGROUND

The interaction among plants and their pollinators has been a major factor which enriched floral traits known as pollination syndromes and promoted the diversification of flowering plants. One of the bee-pollination syndromes in Faboideae with keel blossoms is the formation of a landing platform by wing and keel petals. However, the molecular mechanisms of elaborating a keel blossom remain unclear.

RESULTS

By performing large scale mutagenesis, we isolated and characterized a mutant in Vigna radiata, love on wings (low), which shows developmental defects in petal asymmetry and vasculature, leading to a failure in landing platform formation. We cloned the locus through map-based cloning together with RNA-sequencing (RNA-seq) analysis. We found that LOW encoded a nucleus-localized Dof-like protein and was expressed in the flower provascular and vascular tissues. A single copy of LOW was detected in legumes, in contrast with other taxa where there seems to be at least 2 copies. Thirty one Dof proteins have been identified from the V. radiata's genome, which can be further divided into four Major Cluster of Orthologous Groups (MCOGs). We also showed that ectopic expression of LOW in Arabidopsis driven by its native promoter caused changes in petal vasculature pattern.

CONCLUSIONS

To summarize, our study isolated a legume Dof-like factor LOW from V. radiata, which affects vasculature development in this species and this change can, in turn, impact petal development and overall morphology of keel blossom.

Contribution of biomimetic collagen-ligand interaction to intrafibrillar mineralization

Contemporary models of intrafibrillar mineralization mechanisms are established using collagen fibrils as templates without considering the contribution from collagen-bound apatite nucleation inhibitors. However, collagen matrices destined for mineralization in vertebrates contain bound matrix proteins for intrafibrillar mineralization. Negatively charged, high-molecular weight polycarboxylic acid is cross-linked to reconstituted collagen to create a model for examining the contribution of collagen-ligand interaction to intrafibrillar mineralization. Cryogenic electron microscopy and molecular dynamics simulation show that, after cross-linking to collagen, the bound polyelectrolyte caches prenucleation cluster singlets into chain-like aggregates along the fibrillar surface to increase the pool of mineralization precursors available for intrafibrillar mineralization. Higher-quality mineralized scaffolds with better biomechanical properties are achieved compared with mineralization of unmodified scaffolds in polyelectrolyte-stabilized mineralization solution. Collagen-ligand interaction provides insights on the genesis of heterogeneously mineralized tissues and the potential causes of ectopic calcification in nonmineralized body tissues.

Regulation of compound leaf development in mungbean (Vigna radiata L.) by CUP-SHAPED COTYLEDON/NO APICAL MERISTEM (CUC/NAM) gene

The results provide a significant verification of functional redundancy and diversity of CUC/NAM genes in legumes. The CUP-SHAPED COTYLEDON/NO APICAL MERISTEM (CUC/NAM) orthologs play key roles for plant organ boundary formation and organ development. Here, we performed a forward screen of the gamma irradiation mutagenesis population in mungbean and characterised a mutant, reduced rachis and fused leaflets (rrf1), which gave rise to the formation of compound leaves with reduced rachis and fused leaflets. Map-based cloning revealed that RRF1 encoded a CUC/NAM protein in mungbean. Phylogenetic analysis indicated that legume CUC1/CUC2 genes were classified as belonging to two subclades, and there are different copies of CUC1/CUC2 genes in legumes. Transcriptomic analysis showed that expression levels of a set of developmental regulators, including class I KNOTTED-LIKE HOMEOBOXI (KNOXI) gene and LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene, were altered in rrf1 mutants compared to the wild-type plants. Furthermore, rrf1 genetically interacted with heptafoliate leaflets1 (hel1), a mutant displaying a seven-leaflet compound leaf, to regulate leaf development in mungbean. Our results suggest functional redundancy and diversity of two subclades of CUC1/CUC2 genes in legumes, following the duplication of an ancestral gene.

Genetic control of compound leaf development in the mungbean (Vigna radiata L.)

Many studies suggest that there are distinct regulatory processes controlling compound leaf development in different clades of legumes. Loss of function of the LEAFY (LFY) orthologs results in a reduction of leaf complexity to different degrees in inverted repeat-lacking clade (IRLC) and non-IRLC species. To further understand the role of LFY orthologs and the molecular mechanism in compound leaf development in non-IRLC plants, we studied leaf development in unifoliate leaf (un) mutant, a classical mutant of mungbean (Vigna radiata L.), which showed a complete conversion of compound leaves into simple leaves. Our analysis revealed that UN encoded the mungbean LFY ortholog (VrLFY) and played a significant role in leaf development. In situ RNA hybridization results showed that STM-like KNOXI genes were expressed in compound leaf primordia in mungbean. Furthermore, increased leaflet number in heptafoliate leaflets1 (hel1) mutants was demonstrated to depend on the function of VrLFY and KNOXI genes in mungbean. Our results suggested that HEL1 is a key factor coordinating distinct processes in the control of compound leaf development in mungbean and its related non-IRLC legumes.

Transcriptome-Wide Analysis Reveals the Origin of Peloria in Chinese Cymbidium (Cymbidium sinense)

An orchid flower exhibits a zygomorphic corolla with a well-differentiated labellum. In Cymbidium sinense, many varieties with peloric or pseudopeloric flowers have been bred during centuries of domestication. However, little is known about the molecular basis controlling orchid floral zygomorphy and the origin of these varieties. Here, we studied the floral morphogenesis of C. sinense and transcriptome-wide enriched differentially expressed genes among different varieties. The floral zygomorphy of C. sinense is established in the early developmental process. Out of 27 MIKCC-MADS factors, we found two homeotic MADS genes whose expression was down-regulated in peloric varieties but up-regulated in pseudopeloric varieties. CsAP3-2 expressed in the inner floral organs co-operates with a labellum-specific factor CsAGL6-2, asymmetrically promoting the differentiation of inner tepals. Interestingly, we detected exon deletions on CsAP3-2 in peloric varieties, indicating that loss of B-function results in the origin of peloria. Additional petaloid structures developed when we ectopically expressed these genes in Arabidopsis, suggesting their roles in floral morphogenesis. These findings indicate that the interplay among MADS factors would be crucial for orchid floral zygomorphy, and mutations in these factors may have maintained during artificial selection.

High-Throughput RNA-Seq Data Analysis of the Single Nucleotide Polymorphisms (SNPs) and Zygomorphic Flower Development in Pea (Pisum sativum L.)

Pea (Pisum sativum L.) is a model plant that has been used in classical genetics and organ development studies. However, its large and complex genome has hindered research investigations in pea. Here, we generated transcriptomes from different tissues or organs of three pea accessions using next-generation sequencing to assess single nucleotide polymorphisms (SNPs), and further investigated petal differentially expressed genes to elucidate the mechanisms regulating floral zygomorphy. Eighteen samples were sequenced, which yielded a total of 617 million clean reads, and de novo assembly resulted in 87,137 unigenes. A total of 9044 high-quality SNPs were obtained among the three accessions, and a consensus map was constructed. We further discovered several dorsoventral asymmetrically expressed genes that were confirmed by qRT-PCR among different petals, including previously reported three CYC-like proliferating cell factor (TCP) genes. One MADS-box gene was highly expressed in dorsal petals, and several MYB factors were predominantly expressed among dorsal, lateral, and/or ventral petals, together with a ventrally expressed TCP gene. In sum, our comprehensive database complements the existing resources for comparative genetic mapping and facilitates future investigations in legume zygomorphic flower development.

The CYCLOIDEA-RADIALIS module regulates petal shape and pigmentation, leading to bilateral corolla symmetry in Torenia fournieri (Linderniaceae)

The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3-MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear. Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal-ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like (CYC-like) and RADIALIS-like (RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: TfCYC1, TfCYC2, and TfRAD1. We found that the CYC-RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of TfCYC2 or TfRAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when TfCYC2 was down-regulated or when TfRAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and TfCYC2 binds directly to the regulatory regions of an R2R3-MYB factor gene, TfMYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern. These findings support the existence of a regulatory module that integrates dorsal-ventral patterning and asymmetric corolla pigmentation in T. fournieri.

Efficacy of PARP inhibition in Pde6a mutant mouse models for retinitis pigmentosa depends on the quality and composition of individual human mutations

Retinitis pigmentosa (RP), an inherited blinding disease, is caused by a variety of different mutations that affect retinal photoreceptor function and survival. So far there is neither effective treatment nor cure. We have previously shown that poly(ADP-ribose)polymerase (PARP) acts as a common and critical denominator of cell death in photoreceptors, qualifying it as a potential target for future therapeutic intervention. A significant fraction of RP-causing mutations affect the genes for the rod photoreceptor phosphodiesterase 6A (PDE6A) subunit, but it is not known whether they all engage the same death pathway. Analysing three homozygous point mutations (Pde6a R562W, D670G, and V685M) and one compound heterozygous Pde6a^V685M/R562W mutation in mouse models that match human RP patients, we demonstrate excessive activation of PARP, which correlated in time with the progression of photoreceptor degeneration. The causal involvement of PARP activity in the neurodegenerative process was confirmed in organotypic retinal explant cultures treated with the PARP-selective inhibitor PJ34, using different treatment time-points and durations. Remarkably, the neuroprotective efficacy of PARP inhibition correlated inversely with the strength of the genetically induced insult, with the D670G mutant showing the best treatment effects. Our results highlight PARP as a target for neuroprotective interventions in RP caused by PDE6A mutations and are a first attempt towards personalized, genotype-matched therapy development for RP. In addition, for each of the different mutant situations, our work identifies windows of opportunity for an optimal treatment regimen for further in vivo experimentation and possibly clinical studies.

Systemic administration of strontium or NBD peptide ameliorates early stage cartilage degradation of mouse mandibular condyles

OBJECTIVE

To determine whether mandibular condylar cartilage degradation induced by experimentally abnormal occlusion could be ameliorated via systemic administration of strontium or NBD peptide.

METHODS

Six-week-old female C57BL/6J mice were used. From the seventh day after mock operation or unilateral anterior crossbite (UAC) treatment, the control and UAC mice were further respectively pharmacologically treated for 2 weeks or 4 weeks of saline (CON + Saline and UAC + Saline groups), SrCl2 (CON + SrCl2 and UAC + SrCl2 groups) or NBD peptide (CON + NBD peptide and UAC + NBD peptide groups). Changes in condylar cartilage and subchondral bone were assessed 21 and 35 days after mock operation or UAC procedure by histology and micro-CT. Real-time PCR and/or immunohistochemistry (IHC) were performed to evaluate changes in expression levels of col2a1, aggrecan, ADAMTS-5, tnf-α, il-1β, nfkbia, nuclear factor-kappaB phospho-p65 in condylar cartilage, and rankl/rank/opg in both condylar cartilage and subchondral bone.

RESULTS

Cartilage degradation with decreased col2a1 and aggrecan expression, and increased ADAMTS-5, tnf-α/il1-β, nfkbia and NF-κB phospho-p65 was observed in UAC + Saline groups. Subchondral bone loss with increased osteoclast numbers and decreased opg/rankl ratio was found in UAC + Saline groups compared to age-match CON + Saline groups. Cartilage degradation and subchondral bone loss were reversed by treatment of SrCl2 or NBD peptide while the same dosage in control mice induced few changes in condylar cartilage and subchondral bone.

CONCLUSIONS

The results demonstrate reverse effect of systemic administration of strontium or NBD peptide on UAC-induced condylar cartilage degradation and subchondral bone loss.

Laparoscopic treatment experience of severe acute pancreatitis complicated by peptic ulcer perforation

OBJECTIVE

To explore the clinical effect of emergency laparoscopic repair of perforation and conventional open surgery in the treatment of severe acute pancreatitis (SAP) complicated with peptic ulcer perforation.

PATIENTS AND METHODS

A total of 34 patients diagnosed as severe acute pancreatitis complicated by peptic ulcer perforation were selected as experimental group and a total of 38 patients diagnosed as severe acute pancreatitis complicated by peptic ulcer perforation were selected as control group. The experimental group was treated with emergency laparoscopic perforation repair and the control group was treated with conventional open operation, comparing the difference between the results and the prognosis of the patients.

RESULTS

The success rate of the experimental group and the control group are compared was not statistically significant (p > 0.05). While the operation time, postoperative intestinal function recovery time, the time of drainage tube pulled out and the occurrence of complications in experimental group was significantly lower than those in control group. The survival rate of the experimental group was significantly higher than that of the control group, the recurrence rate was significantly lower than that of the control group (p < 0.05). The high sensitive C reactive protein (hs CRP) and tumor necrosis factor TNF-α levels of the experimental group were significantly lower than those of the control group (p < 0.05).

CONCLUSIONS

Emergency laparoscopic repair of peptic ulcer perforation in the treatment of SAP complicated with perforation is safe and effective, which can reduce the systemic inflammatory response and better than conventional open surgery.

Clinical analysis on argon plasma coagulation (APC) under painless colonoscopy for treatment of patients with colorectal polyp canceration

OBJECTIVE

To investigate the clinical effects of argon plasma coagulation combined high frequency electric knife in treating patients with colorectal polyp canceration.

PATIENTS AND METHODS

56 patients diagnosed with colorectal polyp canceration were divided into control group (n=23) and observation group (n=33). Patients in the control group were treated with high frequency electric band ligation electroexcision while patients in observation group were treated with argon coagulation combined high frequency electric knife therapy. The patients were followed up for 6 months and, then, compared for their clinical effects and prognosis.

RESULTS

The average diameter of the polyp, the ratios of sessile and flat polyps in observation group were significantly higher than those in the control group with p<0.05. While the differences in the ratio of adenomatous polyp, middle and high differentiated as well as leafless polyps between the two groups had no statistical significance with p>0.05. Further, the differences in operation completion rate and polyp resection rate at one time in observation group was significantly higher than those of control group while operative complication rate and operation time was significantly lower than those in the control group with p<0.05. Also, the differences in recurrence in situ and recurrence time did not differ significantly between the two groups.

CONCLUSIONS

Treating colorectal polyps by argon plasma coagulation combined high frequency electric knife could extend polyp resection indication, along with improvement in the operation effect and reduction of complications.

Norepinephrine Regulates Condylar Bone Loss via Comorbid Factors

Degenerative changes of condylar subchondral bone occur frequently in temporomandibular disorders. Although psychologic stresses and occlusal abnormalities have been implicated in temporomandibular disorder, it is not known if these risks represent synergistic comorbid factors that are involved in condylar subchondral bone degradation that is regulated by the sympathetic nervous system. In the present study, chronic immobilization stress (CIS), chemical sympathectomy, and unilateral anterior crossbite (UAC) were sequentially applied in a murine model. Norepinephrine contents in the subjects' serum and condylar subchondral bone were detected by ELISA; bone and cartilage remodeling parameters and related gene expression in the subchondral bone were examined. Subchondral bone loss and increased subchondral bone norepinephrine level were observed in the CIS and UAC groups. These groups exhibited decreased bone mineral density, volume fraction, and bone formation rate; decreased expressions of osterix, collagen I, and osteocalcin; but increased trabecular separation, osteoclast number and surface, and RANKL expression. Combined CIS + UAC produced more severe subchondral bone loss, higher bone norepinephrine level, and decreased chondrocyte density and cartilage thickness when compared to CIS or UAC alone. Sympathectomy simultaneously prevented subchondral bone loss and decreased bone norepinephrine level in all experimental subgroups when compared to the vehicle-treated counterparts. Norepinephrine also decreased mRNA expression of osterix, collagen I, and osteocalcin by mesenchymal stem cells at 7 and 14 d of stimulation and increased the expression of RANKL and RANKL/OPG ratio by mesenchymal stem cells at 2 h. In conclusion, CIS and UAC synergistically promote condylar subchondral bone loss and cartilage degradation; such processes are partially regulated by norepinephrine within subchondral bone.

Wnt5a/Ror2 mediates temporomandibular joint subchondral bone remodeling

Increased subchondral trabecular bone turnover due to imbalanced bone-resorbing and bone-forming activities is a hallmark of osteoarthritis (OA). Wnt5a/Ror2 signaling, which can derive from bone marrow stromal cells (BMSCs), takes a role in modulating osteoblast and osteoclast formation. We showed previously that experimentally unilateral anterior crossbites (UACs) elicited OA-like lesions in mice temporomandibular joints (TMJs), displaying as subchondral trabecular bone loss. Herein, we tested the role of BMSC-derived Wnt5a/Ror2 signaling in regulating osteoclast precursor migration and differentiation in this process. The data confirmed the decreased bone mass, increased tartrate-resistant acid phosphatase (TRAP)-positive cell number, and enhanced osteoclast activity in TMJ subchondral trabecular bone of UAC-treated rats. Interestingly, the osteoblast activity in the tissue of TMJ subchondral trabecular bone of these UAC-treated rats was also enhanced, displaying as upregulated expressions of osteoblast markers and increased proliferation, migration, and differentiation capabilities of the locally isolated BMSCs. These BMSCs showed an increased CXCL12 protein expression level and upregulated messenger RNA expressions of Rankl, Wnt5a, and Ror2. Ex vivo data showed that their capacities of inducing migration and differentiation of osteoclast precursors were enhanced, and these enhanced capabilities were restrained after blocking their Ror2 signaling using small interfering RNA (siRNA) assays. Reducing Ror2 expression in the BMSC cell line by siRNA or blocking the downstream signalings with specific inhibitors also demonstrated a suppression of the capacity of the BMSC cell line to promote Wnt5a-dependent migration (including SP600125 and cyclosporine A) and differentiation (cyclosporine A only) of osteoclast precursors. These findings support the idea that Wnt5a/Ror2 signaling in TMJ subchondral BMSCs enhanced by UAC promoted BMSCs to increase Cxcl12 and Rankl expression, in which JNK and/or Ca(2+)/NFAT pathways were involved and therefore were engaged in enhancing the migration and differentiation of osteoclast precursors, leading to increased osteoclast activity and an overall TMJ subchondral trabecular bone loss in the UAC-treated rats.

Reducing dietary loading decreases mouse temporomandibular joint degradation induced by anterior crossbite prosthesis

OBJECTIVE

Dietary loading has been reported to have an effect on temporomandibular joint (TMJ) remodeling via periodontal-muscular reflex. We therefore examined whether reducing dietary loading decreased TMJ degradation induced by the unilateral anterior crossbite prosthesis as we recently reported.

METHODS

Forty 6-week-old female C57BL/6J mice were randomly divided into two experimental and two control groups. One experimental and one control group received small-size diet and the other two groups received large-size diet. Unilateral anterior crossbite prosthesis was created in the two experimental groups. The TMJ samples were collected 3 weeks after experimental operation. Histological changes in condylar cartilage and subchondral bone were assessed by Hematoxylin & Eosin, toluidine blue, Safranin O and tartrate-resistant acid phosphatase staining. Real-time polymerase chain reaction (PCR) and/or immunohistochemistry were performed to evaluate the expression levels of Collagen II, Aggrecan, a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5) and RANKL/RANK/OPG in TMJ condylar cartilage and/or subchondral bone.

RESULTS

Thinner and degraded cartilage, reduced cartilage cellular density, decreased expression levels of Collagen II and Aggrecan, loss of subchondral bone and enhanced osteoclast activity were observed in TMJs of both experimental groups. However, the cartilage degradation phenotype was less severe and cartilage ADAMTS-5 mRNA was lower while OPG/RANKL ratio in cartilage and subchondral bone was higher in the small-size than large-size diet experimental group. No differences of histomorphology and the tested molecules were found between the two control groups.

CONCLUSIONS

The current findings suggest that a lower level of functional loading by providing small-size diet could reduce TMJ degradation induced by the biomechanical stimulation from abnormal occlusion.

Overexpressed TGF-β in subchondral bone leads to mandibular condyle degradation

Emerging evidence has implied that subchondral bone plays an important role during osteoarthritis (OA) pathology. This study was undertaken to investigate whether abnormalities of the condylar subchondral bone lead to temporomandibular joint (TMJ) OA. We used an osteoblast-specific mutant TGF-β1 transgenic mouse, the CED mouse, in which high levels of active TGF-β1 occur in bone marrow, leading to abnormal bone remodeling. Subchondral bone changes in the mandibular condyles were investigated by micro-CT, and alterations in TMJ condyles were confirmed by histopathological and immunohistochemical analysis. Abnormalities in the condylar subchondral bone, characterized as fluctuant bone mineral density and microstructure and increased but uncoupled activity of osteoclasts and osteoblasts, were apparent in the 1- and 4-month CED mouse groups, while obvious cartilage degradation, in the form of cell-free regions and proteoglycan loss, was observed in the 4-month CED group. In addition, increased numbers of apoptotic chondrocytes and MMP9- and VEGF-positive chondrocytes were observed in the condylar cartilage in the 4-month CED group, but not in the 1-month CED group, compared with their respective age-matched controls. This study demonstrated that progressive degradation of mandibular condylar cartilage could be induced by the abnormal remodeling of the underlying subchondral bone during TMJOA progression.

Occlusal effects on longitudinal bone alterations of the temporomandibular joint

The pathological changes of subchondral bone during osteoarthritis (OA) development in the temporomandibular joint (TMJ) are poorly understood. In the present study, we investigated the longitudinal alterations of subchondral bone using a rat TMJ-OA model developed in our laboratory. Changes in bone mass were examined by micro-CT, and changes in osteoblast and osteoclast activities were analyzed by real-time PCR, immunohistochemistry, and TRAP staining. Subchondral bone loss was detected from 8 weeks after dental occlusion alteration and reached the maximum at 12 weeks, followed by a repair phase until 32 weeks. Although bone mass increased at late stages, poor mechanical structure and lower bone mineral density (BMD) were found in these rats. The numbers of TRAP-positive cells were increased at 12 weeks, while the numbers of osteocalcin-expressing cells were increased at both 12 and 32 weeks. Levels of mRNA expression of TRAP and cathepsin K were increased at 12 weeks, while levels of ALP and osteocalcin were increased at both 12 and 32 weeks. These findings demonstrated that there is an active bone remodeling in subchondral bone in TMJs in response to alteration in occlusion, although new bone was formed with lower BMD and poor mechanical properties.

Differential expression of IGF1, IGFR1 and IGFBP3 in mandibular condylar cartilage between male and female rats applied with malocclusion

This study was designed to investigate the expression differences of insulin-like growth factor-1 (IGF1), IGF type 1 receptor (IGFR1) and IGF-binding protein-3 (IGFBP3) in mandibular condylar cartilage between male and female rats with experimentally created malocclusion. A total of 40 male and 40 female rats were used, and malocclusion was created by moving the first molars mesially and the third molars distally in the experimental group. Animals were killed at the end of the second and fourth weeks. Haematoxylin and eosin (HE) staining was performed to monitor the changes in cartilage morphology and thickness. Immunohistochemistry and real-time PCR were used to detect the expression of IGF1, IGFR1 and IGFBP3. Osteoarthritis (OA)-like changes were observed in the experimental groups, with 2-week females showing larger OA-like regions than 2-week males (P < 0·05). Compared to their age- and sex-matched controls, both 2- and 4-week males in the experimental groups displayed increased cartilage thickness in the posterior regions (P < 0·05). Compared to their age- and sex-matched controls, the expression of IGF1 was lower in 2-week female group (P < 0·05), but higher in 4-week female, 2- and 4-week male experimental groups (P < 0.05). Similarly, the expression of IGFR1 was lower in 2-week female experimental group (P < 0.05), but higher in 2-week male experimental group (P < 0.05). The higher expression of IGFBP3 was observed in 2-week female, 2- and 4-week male experimental groups (P < 0·05). These results indicate that condylar cartilage from male and female rats respond differently to the malocclusion in early stage of OA, with more serious degeneration in females.

Localization of MMP-2, MMP-9, TIMP-1, and TIMP-2 in human coronal dentine

OBJECTIVES

Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play important roles in dentine formation, caries progression and hybrid layer degradation. This study tested the hypothesis that the distribution and concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 are different at different depths of human coronal dentine, including odontoblasts.

METHODS

Protein localization was performed using immunohistochemistry. Co-localization of the MMPs and their inhibitors was conducted using immunofluorescence double labelling. Protein concentrations were measured by ELISA and gelatinolytic potential was assessed with gelatine zymography.

RESULTS

MMP-2 was the main gelatinase in dentine and was concentrated in the odontoblasts, deep dentine and the dentinoenamel junction. TIMP-2 was co-localized with MMP-2 mainly in the odontoblasts but its concentration was low. Both MMP-9 and TIMP-1 showed a decreasing distribution from the deep to the superficial dentine layers; however, the concentration of TIMP-1 was much higher than that of MMP-9. The gelatinolytic potential of dentine protein extracts decreased gradually from deep to superficial dentine.

CONCLUSIONS

The concentrations and distribution patterns of MMP-2, MMP-9, TIMP-1 and TIMP-2, and the gelatinolytic potential of dentine matrix are variable along different dentine depths. Thus, differential collagen degradation potentials may be expected depending upon the depth in which dentine is exposed.

Tetrapod-like Zinc Oxide Whisker Enhancement of Resin Composite

There is an increasing demand for composite resins with both strong antibacterial activity and satisfactory mechanical properties. This study tested the hypothesis that the new antibacterial agent tetrapod-like zinc oxide whisker (T-ZnOw) could simultaneously enhance the antibacterial activity and mechanical properties of a two-component composite resin. The antibacterial activities of the materials were assessed by the broth dilution test and direct contact test. Optical microscopy, scanning electron microscopy, and measurements of the flexural strength, compressive strength, and diametral tensile strength were carried out for mechanical characterization. The results revealed that T-ZnOw provided the resin with strong antibacterial activity and improved mechanical properties in all tested groups. However, the antibacterial activity of the resin with 10% T-ZnOw in the powder component significantly decreased after aging treatment. The incorporation of 5% T-ZnOw into the resin powder was optimal to give appropriate antibacterial activity, long-term antibacterial effectiveness, and mechanical properties.

Enhanced hypotensive, bradycardic, and hypnotic responses to alpha2-adrenergic agonists in spinophilin-null mice are accompanied by increased G protein coupling to the alpha2A-adrenergic receptor

We previously identified spinophilin as a regulator of alpha(2) adrenergic receptor (alpha(2)AR) trafficking and signaling in vitro and in vivo (Science 304:1940-1944, 2004). To assess the generalized role of spinophilin in regulating alpha(2)AR functions in vivo, the present study examined the impact of eliminating spinophilin on alpha(2)AR-evoked cardiovascular and hypnotic responses, previously demonstrated to be mediated by the alpha(2A)AR subtype, after systemic administration of the alpha(2)-agonists 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine (UK14,304) and clonidine in spinophilin-null mice. Mice lacking spinophilin expression display dramatically enhanced and prolonged hypotensive, bradycardic, and sedative-hypnotic responses to alpha(2)AR stimulation. Whereas these changes in sensitivity to alpha(2)AR agonists occur independent of any changes in alpha(2A)AR density or intrinsic affinity for agonist in the brains of spinophilin-null mice compared with wild-type control mice, the coupling of the alpha(2A)AR to cognate G proteins is enhanced in spinophilin-null mice. Thus, brain preparations from spinophilin-null mice demonstrate enhanced guanine nucleotide regulation of UK14,304 binding and evidence of a larger fraction of alpha(2A)AR in the guanine-nucleotide-sensitive higher affinity state compared with those from wild-type mice. These findings suggest that eliminating spinophilin expression in native tissues leads to an enhanced receptor/G protein coupling efficiency that contributes to sensitization of receptor mediated responses in vivo.

Site-Selective Nitration of Tyrosine in Human Serum Albumin by Peroxynitrite

Peroxynitrite, which is formed in biological systems by the reaction of nitric oxide with superoxide anion, is a highly reactive molecule that can lead to cell injury or cell death. Reactions of peroxynitrite under physiological conditions include nitration of tyrosine-containing proteins or peptides, and we have been investigating the behavior of human serum albumin following exposure to peroxynitrite. Peroxynitrite, at relative concentrations ranging from 0.2 to 50 with respect to protein, was added to human serum albumin in buffer at pH 7.2. The resulting mixtures were dialyzed to remove small molecules, dried under vacuum, and then digested with trypsin. The digests were analyzed by high performance liquid chromatography with UV detection at 230 and 354 nm, the latter wavelength being selective for nitrotyrosine. At the higher relative concentrations of peroxynitrite, the 354-nm chromatograms contained a large number of peaks, including at least nine with molecular weights corresponding to nitration of nominal tryptic peptides. Following treatment with the lower relative concentrations of peroxynitrite, however, the 354-nm chromatograms were dominated by only two nitrated peptides; these were identified by comparison of LC retention times and collision-induced decomposition mass spectra as nitro-Y(411)TK(413) and nitro-Y(138)LYEIAR(144). Each of these tyrosines resides in a known reactive site within the protein, i.e., subdomains IIIA and IB, respectively.

O-Ethyl andO-methylN-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)thiocarbamate

In both the title structures, O-ethyl N-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)thiocarbamate, C(17)H(25)NO(10)S, and O-methyl N-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)thiocarbamate, C(16)H(23)NO(10)S, the hexopyranosyl ring adopts the (4)C(1) conformation. All the ring substituents are in equatorial positions. The acetoxymethyl group is in a gauche-gauche conformation. The S atom is in a synperiplanar conformation, while the C-N-C-O linkage is antiperiplanar. N-H.O intermolecular hydrogen bonds link the molecules into infinite chains and these are connected by C-H.O interactions.

Sensitive detection of a plant virus by electrochemical enzyme-linked immunoassay

The electrochemical enzyme-linked immunoassay increases the sensitivity of the detection of cucumber mosaic virus (CMV) by 5-fold compared with the spectrophotometric o-phenylenediamine (OPD) enzyme-linked immunosorbent assay (ELISA). The detection limit for the purified CMV is 1.0 ng/mL and the highest dilution ratio of the infected leaf sap is 1:5.0 x 10(4). The method is based on coupling the oxidation reaction of o-aminophenol (OAP)-H2O2 catalyzed by HRP-IgG conjugate with the electro-reduction of the enzymatic product. The enzymatic product 2-aminophenoxazine-3-one exhibits a sensitive second order derivative linear-sweep voltammetric response at the potential of -0.65 V (vs. Ag/AgCl) in pH 8.0 Britton-Robinson (B-R) buffer solution. So it can be applied to the detection of the plant virus with highly improved sensitivity.

Coordination of the initiation of recombination and the reductional division in meiosis in Saccharomyces cerevisiae

Early exchange (EE) genes are required for the initiation of meiotic recombination in Saccharomyces cerevisiae. Cells with mutations in several EE genes undergo an earlier reductional division (MI), which suggests that the initiation of meiotic recombination is involved in determining proper timing of the division. The different effects of null mutations on the timing of reductional division allow EE genes to be assorted into three classes: mutations in RAD50 or REC102 that confer a very early reductional division; mutations in REC104 or REC114 that confer a division earlier than that of wild-type (WT) cells, but later than that of mutants of the first class; and mutations in MEI4 that do not significantly alter the timing of MI. The very early mutations are epistatic to mutations in the other two classes. We propose a model that accounts for the epistatic relationships and the communication between recombination initiation and the first division. Data in this article indicate that double-strand breaks (DSBs) are not the signal for the normal delay of reductional division; these experiments also confirm that MEI4 is required for the formation of meiotic DSBs. Finally, if a DSB is provided by the HO endonuclease, recombination can occur in the absence of MEI4 and REC104.

[Supercritical fluid extraction and gas chromatographic analysis of four organochlorine pesticides in vegetable]

Supercritical fluid extraction(SFE) of pesticide residues of chlorothalonil, aldrin, dieldrin, and endrin from chives was evaluated. A mixture of vegetable sample: anhydrous magnesium sulfate(2:3) was used for extraction. The extract was analyzed by GC/ECD. The optimum SFE conditions for the pesticides in spiked samples were studied by orthogonal experiment. The chosen conditions were 30.40 MPa, 40 degrees C, 1 min static time, dynamic extraction with 15 mL of CO2, and collection in 3 mL of ethyl acetate. All the pesticides were extracted satisfactorily from their matrix.

Supercritical fluid extraction and off-line clean-up for the analysis of organochlorine pesticide residues in garlic

An approach using supercritical fluid extraction (SFE) followed by clean-up with a AgNO3-loaded Florisil column was utilized for the analysis of four organochlorine pesticides (OCPs) in garlic. The organic sulfur extracted by SFE from garlic was removed by AgNO3 allowing OCPs to be determined by GC-electron-capture detection without interferences. All OCPs recoveries ranged from 85.0% to 110.0% and relative standard deviations were in the range of 3.9-7.2% for spiked samples. The described method may be used to analyze OCPs in garlic on a routine basis.

Improved detection of polycyclic aromatic compounds in complex mixtures by liquid chromatographic fractionation on poly(divinylbenzene) prior to gas chromatography-mass spectrometry. Application to the analysis of diesel particulates

Polycyclic aromatic compounds (PACs) are preferentially retained over other compound classes during high-performance liquid chromatography (HPLC) on poly(divinylbenzene) (PDVB) columns with a dichloromethane mobile phase. PAC retention during HPLC with PDVB/CH2Cl2 is governed by a multi-mode mechanism that has been previously described. This enhanced retention of PACs makes PDVB columns useful for isolating a PAC fraction from highly complex mixtures such as the emissions from fossil-fuels combustion. The cleaned-up PAC fraction yields a simple chromatogram with easily identified and quantified peaks without significant compound loss or danger of contamination. We illustrate the use of this clean-up method for the isolation of the PAC fraction from a standard reference diesel particulate sample.