A pepper RING-finger E3 ligase, CaFIRF1, negatively regulates the high-salt stress response by modulating the stability of CaFAF1

Controlling protein stability or degradation via the ubiquitin-26S proteasome system is a crucial mechanism in plant cellular responses to stress conditions. Previous studies have revealed that the pepper FANTASTIC FOUR-like gene, CaFAF1, plays a positive role in salt tolerance and that, in this process, CaFAF1 protein degradation is delayed. Here, we sought to isolate the E3 ligases potentially responsible for modulating CaFAF1 protein stability in response to salt stress. The pepper RING-type E3 ligase CaFIRF1 (Capsicum  annuum  FAF1  Interacting  RING  Finger protein  1) was found to interact with and ubiquitinate CaFAF1, leading to the degradation of CaFAF1 proteins. In response to high-salt treatments, CaFIRF1-silenced pepper plants exhibited tolerant phenotypes. In contrast, co-silencing of CaFAF1 and CaFIRF1 led to increased sensitivity to high-salt treatments, revealing that CaFIRF1 functions upstream of CaFAF1. A cell-free degradation analysis showed that high-salt treatment suppressed CaFAF1 protein degradation via the 26S proteasome pathway, in which CaFIRF1 is functionally involved. In addition, an in vivo ubiquitination assay revealed that CaFIRF1-mediated ubiquitination of CaFAF1 proteins was reduced by high-salt treatment. Taken together, these findings suggest that the degradation of CaFAF1 mediated by CaFIRF1 has a critical role in pepper plant responses to high salinity.

Devosia rhodophyticola sp. nov. and Devosia algicola sp. nov., isolated from a marine red alga

Two Gram-stain-negative, obligately aerobic, motile rod bacteria, designated as G2-5T and G20-9T, exhibiting catalase- and oxidase-positive activities, were isolated from the phycosphere of a Chondrus species, a marine red alga. Strain G2-5T exhibited optimal growth at 30 °C and pH 5.0-6.0 and in the presence of 0.5-1.0% NaCl. In contrast, strain G20-9T demonstrated optimal growth at 25 °C and pH 6.0 and in the presence of 0.5-1.5% NaCl. Both strains contained ubiquinone-10, summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c), C18 : 0 and 11-methyl-C18 : 1  ω7c, and diphosphatidylglycerol and phosphatidylglycerol as the major respiratory isoprenoid quinone, cellular fatty acids and polar lipids, respectively. The genomic DNA G+C contents were 57.2 mol% for strain G2-5T and 57.5 mol% for strain G20-9T. Strains G2-5T and G20-9T exhibited 98.2 % 16S rRNA gene sequence similarity, along with 82.3 % average nucleotide identity (ANI) and 25.0 % digital DNA-DNA hybridization (dDDH) values, indicating that they represent different species. Phylogenetic analyses based on both 16S rRNA gene and genome sequences revealed that strains G2-5T and G20-9T formed distinct phylogenic lineages within the genus Devosia. Strains G2-5T and G20-9T were most closely related to Devosia limi DSM 17137T and Devosia beringensis S02T with 97.7 and 96.9 % 16S rRNA gene sequence similarities, respectively. The ANI and dDDH values between strains G2-5T and G20-9T and other Devosia species were lower than 73.9 and 19.2 %, respectively, suggesting that they constitute novel species within the genus Devosia. Based on their distinct phenotypic, chemotaxonomic, and molecular characteristics, strains G2-5T and G20-9T represent two novel species of the genus Devosia, for which the names Devosia rhodophyticola sp. nov. (G2-5T=KACC 22601T=JCM 35404T) and Devosia algicola sp. nov. (G20-9T=KACC 22650T=JCM 35405T) are proposed, respectively.

Pepper homeobox abscisic acid signalling-related transcription factor 1, CaHAT1, plays a positive role in drought response

Abscisic acid (ABA) signalling triggers drought resistance mediated by SNF1-related kinase 2s (SnRK2s), which transmits stress signals through the phosphorylation of several downstream factors. However, these kinases and their downstream targets remain elusive in pepper plants. This study aimed to isolate interacting partners of CaSnRK2.6, a homologue of Arabidopsis SnRK2.6/OST1. Among the candidate proteins, we identified a homeodomain-leucine zipper (HD-Zip) class II protein and named it CaHAT1 (Capsicum annuum homeobox ABA signalling related- transcription factor 1). CaHAT1-silenced pepper and -overexpression (OE) transgenic Arabidopsis plants were generated to investigate the in vivo function of CaHAT1 in drought response. Following the application of drought stress, CaHAT1-silenced pepper plants exhibited drought-sensitive phenotypes with reduced ABA-mediated stomatal closure and lower expression of stress-responsive genes compared with control plants. In contrast, CaHAT1-OE transgenic Arabidopsis plants showed the opposite phenotypes, including increased drought resistance and ABA sensitivity. CaHAT1, particularly its N-terminal consensus sequences, was directly phosphorylated by CaSnRK2.6. Furthermore, CaSnRK2.6 kinase activity and CaSnRK2.6-mediated CaHAT1 phosphorylation levels were enhanced by treatment with ABA and drought stress. Taken together, our results indicated that CaHAT1, which is the target protein of CaSnRK2.6, is a positive regulator of drought stress response. This study advances our understanding of CaHAT1-CaSnRK2.6 mediated defence mechanisms in pepper plants against drought stress.

Rhodococcus oxybenzonivorans sp. nov., a benzophenone-3-degrading bacterium, isolated from stream sediment

A Gram-stain-positive, facultative aerobic, oxidase-negative, catalase-positive, non-sporulating, and non-motile bacterium, which degraded benzophenone-3, was isolated from stream sediment collected in the Republic of Korea and designated as strain S2-17T. Cells of this strain were rod-shaped during the early growth phase but became coccoid after the late exponential growth phase. Bacterial growth was observed at 15–37 °C (optimum, 25–30 °C) and pH 6.0–9.5 (optimum, pH 7.5–8.5) and in the presence of 0–9.0 % (w/v) NaCl (optimum, 0–1.0 %). Menaquinone-8 (H2) was the sole isoprenoid quinone, and C16 : 0, C17 : 1  ω8c, summed feature 3 (comprising C16 : 1  ω7c/C16 : 1  ω6c) and C18 : 1  ω9c were the major fatty acids. The cell wall of strain S2-17T contained meso-diaminopimelic acid, and arabinose, galactose and mycolic acid were found in whole-cell hydrolysates, suggesting a chemotype IV cell wall. The G+C content of the genome was 65.6 mol%. Phylogenetic analyses revealed that strain S2-17T formed a phyletic lineage within the genus Rhodococcus and was most closely related to Rhodococcus jostii DSM 44719T (99.2 % 16S rRNA gene sequence similarity). Average nucleotide identity and digital DNA–DNA hybridization values between strain S2-17T and R. jostii DSM 44719T were 82.6 and 26.5 %, respectively, indicating differences between the species. Based on its phenotypic, chemotaxonomic and molecular features, strain S2-17T represents a novel species of the genus Rhodococcus , for which the name Rhodococcus oxybenzonivorans sp. nov. is proposed. The type strain is S2-17T (=KACC 19281T=JCM 32046T).

Massilia soli sp. nov., isolated from soil

A Gram-stain-negative, catalase- and oxidase-positive and aerobic bacterium, designated strain R798T, was isolated from soil in South Korea. Cells were motile rods by means of a single polar flagellum. Growth of strain R798T was observed at 15–35 °C (optimum, 25–30 °C), pH 5.0–8.0 (optimum, 6.0) and 0–1.5 % NaCl (optimum, 0.3 %). Strain R798T contained ubiquinone-8 as the sole isoprenoid quinone, summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c) and C16 : 0 as the major fatty acids and phosphatidylglycerol and phosphatidylethanolamine as the major polar lipids. The DNA G+C content of strain R798T calculated from the whole genome sequence was 63.3 mol%. Phylogenetic analyses based on the 16S rRNA gene and whole genome sequences revealed that strain R798T formed a distinct phyletic lineage within the genus Massilia . Strain R798T was most closely related to Massilia eurypsychrophila B528-3T with a 98.0 % 16S rRNA gene sequence similarity. Average nucleotide identity and digital DNA–DNA hybridization values between strain R798T and the type strain of M. eurypsychrophila were 79.2 and 22.7 %, respectively. Based on the phenotypic, chemotaxonomic and molecular analyses, strain R798T represents a novel species of the genus Massilia , for which the name Massilia soli sp. nov. is proposed. The type strain is R798T (=KACC 22114T=JCM 34601T).

Tobacco ubiquitin-specific protease 12 (NbUBP12) positively modulates drought resistance

Deubiquitination, a type of post-translational modification, cleaves ubiquitin from target proteins, thereby regulating their stability or activity. Deubiquitination enzymes, ubiquitin-specific proteases (UBP/USP), have been reported to be involved in numerous cellular processes in plants, including meristem development, circadian clock regulation, and immunity. In contrast to model plants, however, the functions of UBP in other higher plants remain poorly understood. Here, we isolated a deubiquitination enzyme, ubiquitin-specific protease 12 (NbUBP12), from Nicotiana benthamiana, which shows high sequence homology with the core enzyme regions of UBP12 from other plants. Quantitative reverse-transcription PCR analysis revealed that NbUBP12 gene expression was significantly induced after drought treatment, and its level was higher in seed than in other tissues. Using a virus-induced gene silencing technique, we generated NbUBP12-silenced tobacco plants to analyze NbUBP12 gene function in response to drought stress and found that compared with control plants, NbUBP12-silenced plants exhibited a lower survival rate after exposure to drought stress. In addition, they were characterized by lower leaf surface temperatures and larger stomatal pore size following abscisic acid (ABA) treatment. On the basis of these observations, we suggest that NbUBP12 is involved in modulating drought resistance in N. benthamiana, which is associated with ABA-mediated stomatal closure.

Pepper ubiquitin-specific protease, CaUBP12, positively modulates dehydration resistance by enhancing CaSnRK2.6 stability

Abscisic acid (ABA) is a plant hormone that activates adaptive mechanisms to environmental stress conditions. Plant adaptive mechanisms are complex and highly modulated processes induced by stress-responsive proteins; however, the precise mechanisms by which these processes function under adverse conditions remain unclear. Here, we isolated CaUBP12 (Capsicum annuum ubiquitin-specific protease 12) from pepper (C. annuum) leaves. We show that CaUBP12 expression is significantly induced after exposure to abiotic stress treatments. We conducted loss-of-function and gain-of-function genetic studies to elucidate the biological functions of CaUBP12 in response to ABA and dehydration stress. CaUBP12-silenced pepper plants and CaUBP12-overexpressing Arabidopsis plants displayed dehydration-sensitive and dehydration-tolerant phenotypes, respectively; these phenotypes were characterized by regulation of transpirational water loss and stomatal aperture. Under dehydration stress conditions, CaUBP12-silenced pepper plants and CaUBP12-overexpressing Arabidopsis plants exhibited lower and higher expression levels of stress-related genes, respectively, than the control plants. We isolated a CaUBP12 interaction protein, CaSnRK2.6, which is a homolog of Arabidopsis OST1; degradation of this protein was partially inhibited by CaUBP12. Similar to CaUBP12-silenced pepper plants and CaUBP12-overexpressing Arabidopsis plants, CaSnRK2.6-silenced pepper plants and CaSnRK2.6-overexpressing Arabidopsis displayed dehydration-sensitive and dehydration-tolerant phenotypes, respectively. Our findings suggest that CaUBP12 positively modulates the dehydration stress response by suppressing CaSnRK2.6 protein degradation.

Pepper E3 ligase CaAIRE1 promotes ABA sensitivity and drought tolerance by degradation of protein phosphatase CaAITP1

Plants have developed defense mechanisms to survive in extreme environmental conditions. Abscisic acid (ABA) is a key phytohormone associated with plant adaptation to environmental stress. In this study, we isolated and functionally characterized the pepper RING-type E3 ligase CaAIRE1 (Capsicum annuum ABA Induced RING-type E3 ligase 1) containing the C3HC4-type RING domain. CaAIRE1 was induced by ABA and drought, and CaAIRE1 had E3 ligase activity. CaAIRE1-silenced pepper and CaAIRE1-overexpressing Arabidopsis presented drought-sensitive and drought-tolerant phenotypes, respectively, which were accompanied by altered transpiration water loss and ABA sensitivity. Moreover, we found that CaAIRE1 interacts with and ubiquitinates the pepper type 2C protein phosphatase, CaAITP1 (Capsicum annuum CaAIRE1 Interacting Target Phosphatase 1). A cell-free degradation assay with CaAIRE1-silenced peppers and CaAIRE1-overexpressing Arabidopsis plants revealed that the CaAITP1 protein level was negatively modulated by the expression level of CaAIRE1. In contrast to CaAIRE1, CaAITP1-silenced pepper showed ABA-sensitivity phenotypes. CaAITP1-overexpressing Arabidopsis plants were the most insensitive phenotypes to ABA compared with the wild type and other pepper PP2C-overexpressing plants. Taken together, our data indicate that CaAITP1 plays a major role as a negative modulator in ABA signaling, and CaAIRE1 regulates the ABA signaling and drought response through modulation of CaAITP1 stability.

Post-translational Modifications of bZIP Transcription Factors in Abscisic Acid Signaling and Drought Responses

Under drought stress, plants have developed various mechanisms to survive in the reduced water supply, of which the regulation of stress-related gene expression is responsible for several transcription factors. The basic leucine zippers (bZIPs) are one of the largest and most diverse transcription factor families in plants. Among the 10 Arabidopsis bZIP groups, group A bZIP transcription factors function as a positive or negative regulator in ABA signal transduction and drought stress response. These bZIP transcription factors, which are involved in the drought response, have also been isolated in various plant species such as rice, pepper, potato, and maize. Recent studies have provided substantial evidence that many bZIP transcription factors undergo the post-translational modifications, through which the regulation of their activity or stability affects plant responses to various intracellular or extracellular stimuli. This review aims to address the modulation of the bZIP proteins in ABA signaling and drought responses through phosphorylation, ubiquitination and sumoylation.

Glucose Sensing Materials Based on Carbon Nanotubes for Electrochemical Sensing

There is an urgent need for in situ methods for detecting environmental pollution quickly and accurately. With the development of nanotechnology, a huge potential has been created for the design of highly sensitive sensors with low energy consumption and low costs. If a composite material constructed with carbon nanotubes is used as an electrode in contact with a contaminant, this material undergoes an oxidation-reduction reaction with the contaminant that allows the electrode to function as an electrochemical sensor. This study involved the application of multi-walled carbon nanotubes and modified working electrodes constructed with multi-walled carbon nanotube composites (Ag- and ZnO-multi-walled carbon nanotubes) as electrochemical sensors. These electrodes have good response speed and sensitivity at low concentrations, and they are reusable. To lower the price of these sensors, our goal was to maximize their sensitivity by using the low-cost multiwalled carbon nanotubes in conjunction with silver electroless plating of the multi-walled carbon nanotubes and multi-walled carbon nanotube composites.

The RING finger E3 ligases PIR1 and PIR2 mediate PP2CA degradation to enhance abscisic acid response in Arabidopsis

Recent work has established a core ABA signaling pathway in which A-type PP2C protein phosphatases act as central negative modulators. Although ABA signaling inhibits PP2C activity through ABA-receptor complex, it remains unknown if other mechanisms exist to modulate the level of PP2Cs. Here, we identified a RING domain ubiquitin E3 ligase, PIR1 (PP2CA interacting RING finger protein 1), that interacted with PP2CA. Of the two splicing isoforms, PIR1.2 was isolated from leaf tissue. The PIR1.2 exhibited E3 ligase activity and determined PP2CA stability in the presence of ABA. Consistent with the conclusion that PIR1 promotes ABA signaling by removing PP2CA, a negative modulator, the pir1 knockout mutant displayed an ABA-hyposensitive phenotype. We further showed that PIR2, the closest homologue of PIR1.2, also interacted with PP2CA. Although the pir2 knockout mutant did not display altered ABA response, the pir1-1/pir2 double mutant became more insensitive to ABA than the wild-type or pir1-1 and pir2 single mutants. Using a cell-free degradation assay, ABA promoted degradation of PP2CA, however, such degradation was delayed when incubated with protein extract prepared from the pir1-1/pir2 double mutant. Our data suggest that PIR1 and PIR2 positively modulate ABA signaling by targeting PP2CA for degradation.

Dynamic predictive model for postoperative nausea and vomiting for intravenous fentanyl patient-controlled analgesia

Postoperative nausea and vomiting is the most common side-effect of opioid-based intravenous patient-controlled analgesia. Apfel's simplified risk score is popular but it has some limitations. We developed and validated a dynamic predictive model for nausea or vomiting up to 48 postoperative hours, available as an online web application. Fentanyl was used by 22,144 adult patients for analgesia after non-cardiac surgery under general anaesthesia: we randomly divided them into development (80%) and validation (20%) cohorts, repeated 100 times. We used linear discriminant analysis to select variables for multivariate logistic regression. The incidences of postoperative nausea or vomiting were: 0-48 h, 5691/22,144 (26%); 0-6 h, 2749/22,144 (12%); 6-12 h, 2687/22,144 (12%); 12-18 h, 2624/22,144 (12%); 18-24 h, 1884/22,144 (9%); and 24-48 h, 1082/22,144 (5%). The median (95%CI) area under the receiver operating characteristic curve was 0.72 (0.71-0.73) up to 48 postoperative hours compared with 0.65 (0.64-0.66) for the Apfel model, p < 0.001. The equivalent areas for 0-6 h, 6-12 h, 12-18 h, 18-24 h and 24-48 h were: 0.70 (0.69-0.72); 0.71 (0.69-0.73); 0.69 (0.68-0.71); 0.70 (0.67-0.72); and 0.69 (0.66-0.71), respectively. Our web application allows clinicians to calculate incidences of nausea and vomiting in patients receiving intravenous fentanyl for patient-controlled analgesia.

Roles of pepper bZIP protein CaDILZ1 and its interacting partner RING-type E3 ligase CaDSR1 in modulation of drought tolerance

Abscisic acid (ABA) is a plant hormone that plays a key role in the environmental stress response, especially the induction of ABA-responsive and stress-responsive genes and modulation of the stomatal aperture in response to drought stress. Here, we identified CaDILZ1 (Capsicum annuum Drought-Induced Leucine Zipper 1) belonging to subgroup D of the bZIP protein family; gene functions of this family in response to ABA and drought signaling still remain unknown. CaDILZ1 expression was significantly induced in pepper leaves after exposure to ABA, drought, and NaCl. The CaDILZ1 protein localized in the nucleus of plant cells. In response to drought stress, CaDILZ1-silenced pepper and CaDILZ1-overexpressing Arabidopsis plants exhibited drought-sensitive and drought-tolerant phenotypes, respectively, via altered ABA content, stomatal closure, and expression of ABA-responsive and drought-responsive marker genes. We isolated the RING finger protein CaDSR1 (Capsicum annuum Drought Sensitive RING finger protein 1), which interacted with CaDILZ1 in the nucleus. The CaDSR1 protein exhibited E3 ligase activity and promoted CaDILZ1 degradation via the 26S proteasome pathway. Under drought stress conditions, CaDSR1-silenced pepper and CaDSR1-overexpressing Arabidopsis plants exhibited contrasting phenotypes to those of CaDILZ1-silenced pepper and CaDILZ1-overexpressing Arabidopsis plants. Taken together, our data suggest that CaDSR1 and CaDILZ1 function in ABA-mediated drought stress signaling in pepper plants.

A DEAD-box RNA helicase, RH8, is critical for regulation of ABA signalling and the drought stress response via inhibition of PP2CA activity

Abscisic acid (ABA) is major plant hormone involved in regulating abiotic stress responses. Several studies have established that an ABA-signalling transduction pathway-from ABA perception to response-functions in plant cells. The group A PP2Cs constitute core components of ABA signalling, and they negatively regulate ABA signalling and stress responses. Recent studies have identified and functionally analysed regulators of PP2C activity; however, the precise regulatory mechanisms remain unclear. In the present study, we used a yeast 2-hybrid (Y2H) screening analysis to identify the DEAD-box RNA helicase RH8, which interacted with PP2CA in the nucleus. rh8 knockout mutants exhibited ABA hyposensitivity and drought-susceptible phenotypes characterized by high levels of transpirational water loss via reduced stomatal closure and decreased leaf temperatures. However, rh8/pp2ca double mutants showed ABA hypersensitivity and drought-tolerant phenotypes, indicating that RH8 and PP2CA function in the same ABA-signalling pathway in the drought stress response; moreover, RH8 functions upstream of PP2CA. In vitro phosphatase and kinase assays revealed that RH8 inhibits PP2CA phosphatase activity. Our data indicate that RH8 and its interacting partner PP2CA modulate the drought stress response via ABA-dependent signalling.

Functional analysis of the pepper protein phosphatase, CaAIPP1, and its interacting partner CaAIRF1: Modulation of ABA signalling and the drought stress response

Plant adaptive responses to abiotic stress are coordinated by restriction of plant growth and development. The plant hormone abscisic acid (ABA) is the key regulator of the response to abiotic stress, and its sensitivity determines abiotic stress tolerance levels. We previously showed that the E3 ubiquitin ligase CaAIRF1 functions as a positive regulator of ABA and drought stress via modulation of transcription and stability of the type 2C protein phosphatase CaADIP1. Here, we report the identification and functional analysis of a novel-type 2C phosphatase, CaAIPP1 (Capsicum annuum CaAIRF1 Interacting Protein Phosphatase 1). CaAIPP1 interacted with and was ubiquitinated by CaAIRF1. CaAIPP1 gene expression in pepper leaves was induced by ABA and drought. CaAIPP1 degradation was faster in crude protein extracts from ABA-treated pepper plants than in those from control plants. CaAIPP1-overexpressing plants displayed an ABA-hyposensitive phenotype during seed germination and seedling growth. Moreover, these plants exhibited a drought-sensitive phenotype characterized by high levels of transpirational water loss via decreased stomatal closure and reduced leaf temperatures. Our data indicate that CaAIPP1 is a negative regulator of the drought stress response via ABA-mediated signalling. Our findings provide a valuable insight into the plant defence mechanism that operates during drought stress.

The Pepper RING-Type E3 Ligase CaAIRF1 Regulates ABA and Drought Signaling via CaADIP1 Protein Phosphatase Degradation

Ubiquitin-mediated protein modification occurs at multiple steps of abscisic acid (ABA) signaling. Here, we sought proteins responsible for degradation of the pepper (Capsicum annuum) type 2C protein phosphatase CaADIP1 via the 26S proteasome system. We showed that the RING-type E3 ligase CaAIRF1 (Capsicum annuum ADIP1 Interacting RING Finger Protein 1) interacts with and ubiquitinates CaADIP1. CaADIP1 degradation was slower in crude proteins from CaAIRF1-silenced peppers than in those from control plants. CaAIRF1-silenced pepper plants displayed reduced ABA sensitivity and decreased drought tolerance characterized by delayed stomatal closure and suppressed induction of ABA- and drought-responsive marker genes. In contrast, CaAIRF1-overexpressing Arabidopsis (Arabidopsis thaliana) plants exhibited ABA-hypersensitive and drought-tolerant phenotypes. Moreover, in these plants, CaADIP1-induced ABA hyposensitivity was strongly suppressed by CaAIRF1 overexpression. Our findings highlight a potential new route for fine-tune regulation of ABA signaling in pepper via CaAIRF1 and CaADIP1.

The Pepper WPP Domain Protein, CaWDP1, Acts as a Novel Negative Regulator of Drought Stress via ABA Signaling

Plants are constantly challenged by various environmental stresses, including high salinity and drought, and they have evolved defense mechanisms to counteract the deleterious effects of these stresses. The plant hormone ABA regulates plant growth and developmental processes and mediates abiotic stress responses. Here, we report the identification and characterization of a novel CaWDP1 (Capsicum annuum) protein. The expression of CaWDP1 in pepper leaves was induced by ABA, drought and NaCl treatments, suggesting its role in the abiotic stress response. CaWDP1 proteins show conserved sequence homology with other known WDP1 proteins, and they are localized in the nucleus and cytoplasm. We generated CaWDP1-silenced peppers via virus-induced gene silencing (VIGS). We evaluated the responses of these CaWDP1-silenced pepper plants and CaWDP1-overexpressing (OX) transgenic Arabidopsis plants to ABA and drought. CaWDP1-silenced pepper plants displayed enhanced tolerance to drought stress, and this was characterized by low levels of leaf water loss in the drought-treated leaves. In contrast to CaWDP1-silenced plants, CaWDP1-OX plants exhibited an ABA-hyposensitive and drought-susceptible phenotype, which was accompanied by high levels of leaf water loss, low leaf temperatures, increased stomatal pore size and low expression levels of stress-responsive genes. Our results indicate that CaWDP1, a novel pepper negative regulator of ABA, regulates the ABA-mediated defense response to drought stress.

Identification and functional characterization of the pepper CaDRT1 gene involved in the ABA-mediated drought stress response

Plants are constantly challenged by various environmental stresses, including high salinity and drought, and they have evolved defense mechanisms to counteract the deleterious effects of these stresses. The plant hormone abscisic acid (ABA) regulates plant growth and developmental processes and mediates abiotic stress responses. Here, we identified the Capsicum annuum DRought Tolerance 1 (CaDRT1) gene from pepper leaves treated with ABA. CaDRT1 was strongly expressed in pepper leaves in response to environmental stresses and after ABA treatment, suggesting that the CaDRT1 protein functions in the abiotic stress response. Knockdown expression of CaDRT1 via virus-induced gene silencing resulted in a high level of drought susceptibility, and this was characterized by increased transpirational water loss via decreased stomatal closure. CaDRT1-overexpressing (OX) Arabidopsis plants exhibited an ABA-hypersensitive phenotype during the germinative, seedling, and adult stages. Additionally, these CaDRT1-OX plants exhibited a drought-tolerant phenotype characterized by low levels of transpirational water loss, high leaf temperatures, increased stomatal closure, and enhanced expression levels of drought-responsive genes. Taken together, our results suggest that CaDRT1 is a positive regulator of the ABA-mediated drought stress response.

RING Type E3 Ligase CaAIR1 in Pepper Acts in the Regulation of ABA Signaling and Drought Stress Response

Several E3 ubiquitin ligases have been associated with the response to abiotic and biotic stresses in higher plants. Here, we report that the hot pepper (Capsicum annuum) ABA-Insensitive RING protein 1 gene (CaAIR1) is essential for a hypersensitive response to drought stress. CaAIR1 contains a C3HC4-type RING finger motif, which plays a role for attachment of ubiquitins to the target protein, and a putative transmembrane domain. The expression levels of CaAIR1 are up-regulated in pepper leaves by ABA treatments, drought and NaCl, suggesting its role in the response to abiotic stress. Our analysis showed that CaAIR1 displays self-ubiquitination and is localized in the nucleus. We generated CaAIR1-silenced peppers via virus-induced gene silencing (VIGS) and CaAIR1-overexpressing (OX) transgenic Arabidopsis plants to evaluate their responses to ABA and drought. VIGS of CaAIR1 in pepper plants conferred an enhanced tolerance to drought stress, which was accompanied by low levels of transpirational water loss in the drought-treated leaves. CaAIR1-OX plants displayed an impaired sensitivity to ABA during seed germination, seedling and adult stages. Moreover, these plants showed enhanced sensitivity to drought stress because of reduced stomatal closure and decreased expression of stress-responsive genes. Thus, our data indicate that CaAIR1 is a negative regulator of the ABA-mediated drought stress tolerance mechanism.

The pepper late embryogenesis abundant protein CaLEA1 acts in regulating abscisic acid signaling, drought and salt stress response

As sessile organisms, plants are constantly challenged by environmental stresses, including drought and high salinity. Among the various abiotic stresses, osmotic stress is one of the most important factors for growth and significantly reduces crop productivity in agriculture. Here, we report a function of the CaLEA1 protein in the defense responses of plants to osmotic stress. Our analyses showed that the CaLEA1 gene was strongly induced in pepper leaves exposed to drought and increased salinity. Furthermore, we determined that the CaLEA1 protein has a late embryogenesis abundant (LEA)_3 homolog domain highly conserved among other known group 5 LEA proteins and is localized in the processing body. We generated CaLEA1-silenced peppers and CaLEA1-overexpressing (OX) transgenic Arabidopsis plants to evaluate their responses to dehydration and high salinity. Virus-induced gene silencing of CaLEA1 in pepper plants conferred enhanced sensitivity to drought and salt stresses, which was accompanied by high levels of lipid peroxidation in dehydrated and NaCl-treated leaves. CaLEA1-OX plants exhibited enhanced sensitivity to abscisic acid (ABA) during seed germination and in the seedling stage; furthermore, these plants were more tolerant to drought and salt stress than the wild-type plants because of enhanced stomatal closure and increased expression of stress-responsive genes. Collectively, our data suggest that CaLEA1 positively regulates drought and salinity tolerance through ABA-mediated cell signaling.

Function of ABA in Stomatal Defense against Biotic and Drought Stresses

The plant hormone abscisic acid (ABA) regulates many key processes involved in plant development and adaptation to biotic and abiotic stresses. Under stress conditions, plants synthesize ABA in various organs and initiate defense mechanisms, such as the regulation of stomatal aperture and expression of defense-related genes conferring resistance to environmental stresses. The regulation of stomatal opening and closure is important to pathogen defense and control of transpirational water loss. Recent studies using a combination of approaches, including genetics, physiology, and molecular biology, have contributed considerably to our understanding of ABA signal transduction. A number of proteins associated with ABA signaling and responses—especially ABA receptors—have been identified. ABA signal transduction initiates signal perception by ABA receptors and transfer via downstream proteins, including protein kinases and phosphatases. In the present review, we focus on the function of ABA in stomatal defense against biotic and abiotic stresses, through analysis of each ABA signal component and the relationships of these components in the complex network of interactions. In particular, two ABA signal pathway models in response to biotic and abiotic stress were proposed, from stress signaling to stomatal closure, involving the pyrabactin resistance (PYR)/PYR-like (PYL) or regulatory component of ABA receptor (RCAR) family proteins, 2C-type protein phosphatases, and SnRK2-type protein kinases.

Function of ABA in Stomatal Defense against Biotic and Drought Stresses

The plant hormone abscisic acid (ABA) regulates many key processes involved in plant development and adaptation to biotic and abiotic stresses. Under stress conditions, plants synthesize ABA in various organs and initiate defense mechanisms, such as the regulation of stomatal aperture and expression of defense-related genes conferring resistance to environmental stresses. The regulation of stomatal opening and closure is important to pathogen defense and control of transpirational water loss. Recent studies using a combination of approaches, including genetics, physiology, and molecular biology, have contributed considerably to our understanding of ABA signal transduction. A number of proteins associated with ABA signaling and responses--especially ABA receptors--have been identified. ABA signal transduction initiates signal perception by ABA receptors and transfer via downstream proteins, including protein kinases and phosphatases. In the present review, we focus on the function of ABA in stomatal defense against biotic and abiotic stresses, through analysis of each ABA signal component and the relationships of these components in the complex network of interactions. In particular, two ABA signal pathway models in response to biotic and abiotic stress were proposed, from stress signaling to stomatal closure, involving the pyrabactin resistance (PYR)/PYR-like (PYL) or regulatory component of ABA receptor (RCAR) family proteins, 2C-type protein phosphatases, and SnRK2-type protein kinases.

Expression and Functional Roles of the Pepper Pathogen-Induced bZIP Transcription Factor CabZIP2 in Enhanced Disease Resistance to Bacterial Pathogen Infection

A pepper bZIP transcription factor gene, CabZIP2, was isolated from pepper leaves infected with a virulent strain of Xanthomonas campestris pv. vesicatoria. Transient expression analysis of the CabZIP2-GFP fusion protein in Nicotiana benthamiana revealed that the CabZIP2 protein is localized in the cytoplasm as well as the nucleus. The acidic domain in the N-terminal region of CabZIP2 that is fused to the GAL4 DNA-binding domain is required to activate the transcription of reporter genes in yeast. Transcription of CabZIP2 is induced in pepper plants inoculated with virulent or avirulent strains of X. campestris pv. vesicatoria. The CabZIP2 gene is also induced by defense-related hormones such as salicylic acid, methyl jasmonate, and ethylene. To elucidate the in vivo function of the CabZIP2 gene in plant defense, virus-induced gene silencing in pepper and overexpression in Arabidopsis were used. CabZIP2-silenced pepper plants were susceptible to infection by the virulent strain of X. campestris pv. vesicatoria, which was accompanied by reduced expression of defense-related genes such as CaBPR1 and CaAMP1. CabZIP2 overexpression in transgenic Arabidopsis plants conferred enhanced resistance to Pseudomonas syringae pv. tomato DC3000. Together, these results suggest that CabZIP2 is involved in bacterial disease resistance.

Identification and functional roles of CaDIN1 in abscisic acid signaling and drought sensitivity

Plants frequently face challenges caused by various abiotic stresses, including drought, and have evolved defense mechanisms to counteract the deleterious effects of these stresses. The phytohormone abscisic acid (ABA) is involved in signal transduction pathways that mediate defense responses of plants to abiotic stress. Here, we report a new function of the CaDIN1 protein in defense responses to abiotic stress. The CaDIN1 gene was strongly induced in pepper leaves exposed to ABA, NaCl, and drought stresses. CaDIN1 proteins share high sequence homology with other known DIN1 proteins and are localized in chloroplasts. We generated CaDIN1-silenced peppers and overexpressing transgenic Arabidopsis plants and evaluated their response to ABA and drought stress. Virus-induced gene silencing of CaDIN1 in pepper plants conferred enhanced tolerance to drought stress, which was accompanied by low levels of lipid peroxidation in dehydrated leaves. CaDIN1-overexpressing transgenic plants exhibited reduced sensitivity to ABA during seed germination and seedling stages. Transgenic plants were more vulnerable to drought than that by the wild-type plants because of decreased expression of ABA responsive stress-related genes and reduced stomatal closure in response to ABA. Together, these results suggest that CaDIN1 modulates drought sensitivity through ABA-mediated cell signaling.

Arabidopsis PYL8 Plays an Important Role for ABA Signaling and Drought Stress Responses

Plants are frequently exposed to numerous environmental stresses such as dehydration and high salinity, and have developed elaborate mechanisms to counteract the deleterious effects of stress. The phytohormone abscisic acid (ABA) plays a critical role as an integrator of plant responses to water-limited condition to activate ABA signal transduction pathway. Although perception of ABA has been suggested to be important, the function of each ABA receptor remains elusive in dehydration condition. Here, we show that ABA receptor, pyrabactin resistance-like protein 8 (PYL8), functions in dehydration conditions. Transgenic plants overexpressing PYL8 exhibited hypersensitive phenotype to ABA in seed germination, seedling growth and establishment. We found that hypersensitivity to ABA of transgenic plants results in high degrees of stomatal closure in response to ABA leading to low transpiration rates and ultimately more vulnerable to drought than the wild-type plants. In addition, high expression of ABA maker genes also contributes to altered drought tolerance phenotype. Overall, this work emphasizes the importance of ABA signaling by ABA receptor in stomata during defense response to drought stress.

Stem cell transplantation into the intraventricular space via an Ommaya reservoir in a patient with amyotrophic lateral sclerosis

Stem cells have been highlighted for a possible clinical trial in amyotrophic lateral sclerosis (ALS), and have been employed in SOD1 mice and ALS patients. Human trials for stem cell transplantations have used intrathecal route by lumbar puncture. However, stem cells introduced via lumbar injection would tend to sink downwards rather than ascending to the brain and cervical and thoracic spinal cord. Therefore, we adopted for intraventricular injection via an Ommaya reservoir, and wished to test the practicality of intraventricular stem cell injection in ALS. In the case presented autologous mesenchymal stromal cells (MSCs) were isolated from the bone marrow of a male patient with ALS who underwent insertion of an Ommaya reservoir. Expanded MSCs (hBM-MSCs: dose of 1 X 106 cells/kg) were suspended in autologous CSF and directly transplanted into the ALS patient's lateral ventricle via the Ommaya reservoir. Clinical, laboratory, and radiographic evaluation of the patient revealed no serious adverse effects related to the stem cell therapy. Intraventricular injection with an optimized number of cells is safe, and is a potential route for stem cell therapy in patients with ALS. Intraventricular injection via an Ommaya reservoir makes repetitive injection of stem cells easy and reliable even in far advanced ALS patients.

Functional roles of the protein phosphatase 2C, AtAIP1, in abscisic acid signaling and sugar tolerance in Arabidopsis

Biotic signaling molecules including abscisic acid (ABA) serve as an integrator of abiotic stress including high salinity and drought. Recent studies have led to the identification of an ABA signaling pathway from the ABA receptor to stomatal closure in response to abiotic stress. ABA is linked to ABA receptors and protein phosphatase 2C (PP2C) members. In this study, we reconstituted the ABA signaling pathway as a protein-protein interaction between the RCAR type receptor and AIP1, which is one of the group A PP2C member. Several ABA receptors interact with AIP1 in an ABA dependent or independent manner. aip1 null mutant plants exhibited reduced sensitivity to ABA and glucose during the seed germination and seedling stage. Taken together, these results demonstrated that AIP1 is associated with ABA-mediated cell signaling and function as positive regulators of ABA.

Reduction of pain on injection of propofol: combination of pretreatment of remifentanil and premixture of lidocaine with propofol

BACKGROUNDS AND OBJECTIVE

There is a high incidence of pain following intravenous injection of propofol, and many studies have been conducted to find a way of reducing this. The administration of lidocaine and, recently, remifentanil has also been used for this purpose, but it is only partially effective. Thus, the purpose of this study was to investigate the analgesic effect of a combination of pretreatment with remifentanil and premixture of lidocaine with propofol and to compare either treatment alone during propofol injection in dorsal hand-veins.

METHODS

In a prospective, randomized, double-blinded trial, we studied 141 adult patients scheduled for elective surgery. The combination of pretreatment of remifentanil (0.35 microg kg(-1) min(-1)) and a premixture of lidocaine with propofol (mixture of propofol 1% and lidocaine 1% in a 10:1 ratio) was compared with either treatment alone in the prevention of pain on propofol injection. Pain was assessed on a four-point scale (0=none, 1=mild, 2=moderate, 3=severe) during propofol injection. Patients in Group B received remifentanil (0.35 microg kg(-1) min(-1)) 30 s before the injection of propofol.

RESULTS

The reduction of pain on propofol injection was similar in both the remifentanil pretreatment and lidocaine premixture groups (62.2% vs. 62.2%). Combination therapy was associated with a higher incidence of patients without pain (91.3%) than either treatment alone (P<0.001). On analysing the injection pain scores, we found a significant reduction of the score in the remifentanil and lidocaine Group C compared with the lidocaine Group A (P<0.001) and the remifentanil Group B (P<0.001).

CONCLUSIONS

The combination of pretreatment of remifentanil and premixture of lidocaine with propofol was more effective in reducing the incidence of pain on injection of propofol than either treatment alone.

Intrathecal Implants of Microencapsulated Xenogenic Chromaffin Cells Provide a Long-Term Source of Analgesic Substances

Adrenal medullary chromaffin cells secrete several neuroactive substances including catecholamines and opioid peptides that produce analgesic effects in the central nervous system. This study was designed to investigate whether intrathecal microencapsulated chromaffin cells could release analgesic materials producing antiallodynic effects on the chronic neuropathic pain in rats induced by chronic constriction injury (CCI) of the sciatic nerve. Prior to intrathecal implantation, chromaffin cells were encapsulated with alginate and poly-L-lysine to protect them from the host immune system. Behavior tests were performed before CCI, 1 week later, and at 4, 7, 14, 21, 28 days postimplantation. At the end of study, we performed cerebrospinal fluid (CSF) collection and implant retrieval. We observed that intrathecal implantation of encapsulated xenogenic chromaffin cells reduced the mechanical and cold allodynia in a model of neuropathic pain. CSF levels of catecholamines and metenkephalin in the rats that received implants were higher than the controls. In addition, we observed chronic survival of implants. These results suggested that intrathecal microencapsulated chromaffin cells may represent a new approach to chronic neuropathic pain management.

HCV core protein modulates Rb pathway through pRb down-regulation and E2F-1 up-regulation

It has been recognized that the HCV (hepatitis C virus) core protein plays an important role in hepatocarcinogenesis. The functional inactivation of the Rb pathway appears to be a major event for multi-step cancer carcinogenesis. To elucidate the role of the HCV core protein in hepatocarcinogenesis, we investigated the effect of the HCV core protein on the Rb pathway in both Rat-1 cell lines, stably expressing the HCV core protein and the doxycycline-regulated cell lines. The HCV core stable transfectants showed a dramatic decrease in the pRb levels and E2F-1 up-regulation. In the doxycycline-regulated cell lines, the pRb levels were significantly decreased which are followed by E2F-1 up-regulation. HCV core stable transfectants showed higher cell growth rates and were sensitize to apoptosis. Thus, our results first indicate that the HCV core protein decreases the expression of pRb, thereby allowing E2F-1 to be constitutively active, which is thought to result in rapid cell proliferation or sensitizing to apoptosis.

Failure to induce inhibition of cyclin A and up-regulation of p21 expression in phorbol ester-resistant U937 cells by phorbol ester

Differentiation resistant U937 cells were derived from parental U937 cells by selecting for continuously growing U937 cells in cell cultures continuously exposed to phorbol 12 myristate 13-acetate (PMA). Unlike in other known PMA resistant U937, the basal expression of protein kinase C (PKC) isozymes in these PMA resistant cells (R-U937) was significantly decreased. Subsequent analyses revealed differences between the wild type U937 and the R-U937 cells with respect to G1 phase arrest, which seemed to occur in U937 because of low levels of cdk2 kinase activity. This abolished cdk2 kinase activity is mainly due to inhibition of cdk2 phosphorylation, cyclin A down-regulation and cyclin dependent kinase inhibitor p21 up-regulation. Our data suggest that events down-stream of PKC activation may mediate cell cycle control. Thus, the R-U937 cells could be useful for further PKC mediated cell cycle control studies.

Effect of heat shock on the vascular contractility in isolated rat aorta

Stresses such as heat shock, ischemia, and irradiation have been known to induce heat shock proteins in various tissues. We investigated the effects of heat shock on the vascular contractility by using isolated rat aorta. Rat thoracic aortic rings were mounted in an organ bath maintained at 37 degrees C. For heat shock, aortic ring preparations were exposed to 42 degrees C for either 15 or 45 min (heat shock group), whereas the control group was left at 37 degrees C. Eight hours after heat shock, aortic ring preparations were subjected to contractions with high K(+) membrane-depolarizing solution. After functional study, tissues were frozen for measurement of heat shock protein 70 (HSP70). Heat shock not only increased the expression of HSP70 in the rat aorta, but also augmented contractions to KCl whether endothelium was present or denuded. Short exposure of tissues to 42 degrees C for 15 min did not work either. These results suggest that heat shock increases vascular contractility in isolated aortic strips.