Effect of passive smoking exposure on risk of type 2 diabetes: a systematic review and meta-analysis of prospective cohort studies.

Objective: The effect of passive smoking exposure on the risk of type 2 diabetes has not been systematically studied. A meta-analysis was conducted to assess the association between passive smoking exposure and the risk of diabetes. Methods: We searched three major databases up to 31 October 2022 to identify relevant prospective cohort studies on the association between passive smoking and the risk of type 2 diabetes. The pooled relative risk (RR) and 95% confidence interval (CI) for the association between passive smoking exposure and the risk of type 2 diabetes were analyzed using a fixed-effect model. Results: Ten prospective cohort studies were included in this meta-analysis, with a total of 251,620 participants involved. The pooled RR showed a significantly positive association between nonsmokers exposed to passive smoking and type 2 diabetes as compared to non-smokers who were not exposed to passive smoking [RR = 1.27; 95% CI (1.19, 1.36); p < 0.001]. Sensitivity analysis indicated that the pooled RR was not substantially affected by any of the individual studies. Conclusion: Exposure to passive smoking increases the risk of type 2 diabetes. This study may have a positive effect on the prevention of type 2 diabetes. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023372532.

Plasma metabolomic characterization of premature ovarian insufficiency.

BACKGROUND: Premature ovarian insufficiency (POI) patients are predisposed to metabolic disturbances, including in lipid metabolism and glucose metabolism, and metabolic disorders appear to be a prerequisite of the typical long-term complications of POI, such as cardiovascular diseases or osteoporosis. However, the metabolic changes underlying the development of POI and its subsequent complications are incompletely understood, and there are few studies characterizing the disturbed metabolome in POI patients. The aim of this study was to characterize the plasma metabolome in POI by using ultrahigh-performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) metabolomics and to evaluate whether these disturbances identified in the plasma metabolome relate to ovarian reserve and have diagnostic value in POI. METHODS: This observational study recruited 30 POI patients and 30 age- and body mass index (BMI)-matched controls in the Center for Reproductive Medicine, Department of Gynecology and Obstetrics, Nanfang Hospital, Southern Medical University, from January 2018 to October 2020. Fasting venous blood was collected at 9:00 am on days 2-4 of the menstrual cycle and centrifuged for analysis. An untargeted quantitative metabolomic analysis was performed using UHPLC-MS/MS. RESULTS: Our study identified 48 upregulated and 21 downregulated positive metabolites, and 13 upregulated and 48 downregulated negative metabolites in the plasma of POI patients. The differentially regulated metabolites were involved in pathways such as caffeine metabolism and ubiquinone and other terpenoid-quinone biosynthesis. Six metabolites with an AUC value > 0.8, including arachidonoyl amide, 3-hydroxy-3-methylbutanoic acid, dihexyl nonanedioate, 18-HETE, cystine, and PG (16:0/18:1), were correlated with ovarian reserve and thus have the potential to be diagnostic biomarkers of POI. CONCLUSION: This UHPLC-MS/MS untargeted metabolomics study revealed differentially expressed metabolites in the plasma of patients with POI. The differential metabolites may not only be involved in the aetiology of POI but also contribute to its major complications. These findings offer a panoramic view of the plasma metabolite changes caused by POI, which may provide useful diagnostic and therapeutic clues for POI disease.

Efficacy and safety of remimazolam besylate in bronchoscopy for adults: A multicenter, randomized, double-blind, positive-controlled clinical study.

Background: With the development of fiberoptic bronchoscopy in the diagnosis and treatment of various pulmonary diseases, the anesthesia/sedation requirements are becoming more demanding, posing great challenges for patient safety while ensuring a smooth examination/surgery process. Remimazolam, a brand-new ultra-short-acting anesthetic, may compensate for the shortcomings of current anesthetic/sedation strategies in bronchoscopy. Methods: This study was a prospective, multicenter, randomized, double-blind, parallel positive controlled phase 3 clinical trial. Subjects were randomized to receive 0.2 mg/kg remimazolam besylate or 2 mg/kg propofol during bronchoscopy to evaluate the efficacy and safety of remimazolam. Results: A total of 154 subjects were successfully sedated in both the remimazolam group and the propofol group, with a success rate of 99.4% (95%CI of the adjusted difference -6.7 × 10%-6% to -5.1 × 10%-6%). The sedative effect of remimazolam was noninferior to that of propofol based on the prespecified noninferiority margin of -5%. Compared with the propofol group, the time of loss of consciousness in the remimazolam group (median 61 vs. 48s, p < 0.001), the time from the end of study drug administration to complete awakening (median 17.60 vs. 12.80 min, p < 0.001), the time from the end of bronchoscopy to complete awakening (median 11.00 vs. 7.00 min, p < 0.001), the time from the end of study drug administration to removal of monitoring (median 19.50 vs. 14.50 min, p < 0.001), and the time from the end of bronchoscopy to removal of monitoring (median 12.70 vs. 8.60 min, p < 0.001) were slightly longer. The incidence of Adverse Events in the remimazolam group and the propofol group (74.8% vs. 77.4%, p = 0.59) was not statistically significant, and none of them had Serious Adverse Events. The incidence of hypotension (13.5% vs. 29.7%, p < 0.001), hypotension requiring treatment (1.9% vs. 7.7%, p = 0.017), and injection pain (0.6% vs. 16.8%, p < 0.001) were significantly lower in the remimazolam group than in the propofol group. Conclusion: Moderate sedation with 0.2 mg/kg remimazolam besylate is effective and safe during bronchoscopy. The incidence of hypotension and injection pain was less than with propofol, but the time to loss of consciousness and recovery were slightly longer. Clinical Trial Registration: clinicaltrials.gov, ChiCTR2000039753.

Simvastatin inhibits the inflammation and oxidative stress of human neutrophils in sepsis via autophagy induction.

Simvastatin exerts a protective effect during sepsis (SP) in animal models; however, the underlying mechanism is not completely understood, particularly in human SP. Neutrophils are a critical effector in the host inflammatory response to SP. Therefore, the present study aimed to investigate the effect of simvastatin on neutrophils in human SP. Neutrophils were isolated from the peripheral venous blood of adult patients with SP and healthy volunteers (HP). Cell viability was analyzed using the MTT assay. Intracellular reactive oxygen species (ROS) generation and the concentrations of inflammatory mediators were also assessed using flow cytometry and ELISA. The results demonstrated that the cell viability of neutrophils from the SP group was significantly decreased compared with that in the HP group, and that treatment with simvastatin partly reversed the reduced cell viability. Furthermore, simvastatin administration significantly decreased ROS production and the concentrations of TNF­α and IL­6, which were significantly increased in neutrophils isolated from the SP group. Simvastatin also enhanced autophagy induction, as indicated by the promotion of the conversion of LC3I to LC3II and the increased expression levels of Beclin 1 in SP neutrophils. Treatment with 3­methyladenine, an autophagy inhibitor, completely blocked the protective effects of simvastatin on neutrophils from SP, including the effects of simvastatin on the inhibition of inflammation, oxidative stress and improving cell viability. Collectively, the present study provided evidence for the simvastatin­induced autophagic process of neutrophils involved in human SP, which protects neutrophils and partially attenuates the inflammatory response and oxidative stress. Therefore, the augmentation of neutrophil autophagy may serve as a potential therapeutic target for patients with SP.

Let-7e modulates the proliferation and the autophagy of human granulosa cells by suppressing p21 signaling pathway in polycystic ovary syndrome without hyperandrogenism.

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive-aged women, and its pathogenesis is still under debate. Recent studies suggest crucial roles for microRNAs (miRNAs) in PCOS development. The let-7 family miRNAs constitute the most abundant miRNAs in human granulosa cells (GCs), and plays an important role in follicular development. However, research on the let-7e implications of the non-hyperandrogenic (non-HA) phenotype remains unclear. This study aimed at determining the role of let-7e in the progression of PCOS. We performed quantitative real-time PCR to examine the levels of let-7e in fifty-two non-HA PCOS patients and fifty-two controls. A receiver operating characteristic (ROC) curve were used to reveal the diagnostic value of let-7e in non-HA PCOS. Using an immortalized human granulosa cell line, KGN, we investigated the influence of let-7e on cell proliferation and autophagy. Our data substantiated the expression of let-7e was significantly increased in non-HA PCOS group, and associated with an increased antral follicle count. The ROC curve indicated a major separation between non-HA PCOS group and the control group. Let-7e knockdown suppressed cell proliferation and enhanced cell autophagy by activating p21 pathway. Conversely, let-7e overexpression promoted cell proliferation and inhibited cell autophagy by suppressing p21 pathway. Our results indicate that increased let-7e levels in non-HA PCOS GCs may contribute to excessive follicular activation and growth, thereby involving in the pathogenesis of PCOS. Let-7e may thus be a potential therapeutic target in non-HA PCOS.

Intestinal stricture in Crohn's disease: A 2020 update.

Crohn's disease (CD) is a chronic and relapsing-remitting inflammatory disorder of the gastrointestinal tract. Approximately 70% of patients inevitably develop fibrosis-associated intestinal stricture after 10 years of CD diagnosis, which seriously affects their quality of life. Current therapies play limited role in preventing or reversing the process of fibrosis and no specific anti-fibrotic therapy is yet available. Nearly half of patients thus have no alternative but to receive surgery. The potential mechanisms of intestinal fibrosis remain poorly understood; extracellular matrix remodeling, aberrant immune response, intestinal microbiome imbalance and creeping fat might exert fundamental influences on the multiple physiological and pathophysiological processes. Recently, the emerging new diagnostic techniques have markedly promoted an accurate assessment of intestinal stricture by distinguishing fibrosis from inflammation, which is crucial for guiding treatment and predicting prognosis. In this review, we concisely summarized the key studies published in the year 2020 covering pathogenesis, diagnostic modalities, and therapeutic strategy of intestinal stricture. A comprehensive and timely review of the updated researches in intestinal stricture could provide insight to further elucidate its pathogenesis and identify novel drug targets with anti-fibrotic potentiality.

Organophosphorus insecticide interacts with the pheromone-binding proteins of Athetis lepigone: Implication for olfactory dysfunction.

Athetis lepigone is one of the most severe polyphagous pests, and it has developed resistance to different chemical insecticides. Insects primarily rely on the olfactory system to recognize various environmental chemicals, including xenobiotics such as insecticides. Here, we expressed two A. lepigone pheromone-binding proteins (AlepPBP2 and AlepPBP3), and observed they had higher binding affinities to phoxim than other insecticides, with Ki was 3.30 ±â€¯0.38 µM and 3.27 ±â€¯0.10 µM, respectively. Molecular dynamics simulation, binding mode analysis, and computational alanine scanning showed that six residues (Phe15, Phe39, Ile55, Leu65, Ile97, and Phe122) of AlepPBP2 and three residues (Phe12, Ile52, and Ile134) of AlepPBP3 maybe as potential residues that can change protein ability to bind an organophosphorus insecticide phoxim. Then, we used site-directed mutagenesis assay to mutate these residues into alanine, respectively. Subsequently, the binding assays displayed that Phe15, Phe39, and Ile97 of AlepPBP2, Phe12 and Ile134 of AlepPBP3 caused a significant decrease of AlepPBPs binding ability to phoxim, suggesting they should play crucial roles in the AlepPBPs/phoxim interactions. Our findings could further advance in using PBPs as unique targets to design and develop precise and environmentally-friendly pest control agents with high insecticidal potential using a computer-aided drug design (CADD) approach.

Key Amino Acid Residues Influencing Binding Affinities of Pheromone-Binding Protein from Athetis lepigone to Two Sex Pheromones.

Athetis lepigone is a polyphagous pest found around the world that feeds on maize, wheat, and various other important crops. Although it exhibits a degree of resistance to various chemical insecticides, an effective pest-control method has not yet been developed. The sex pheromone communication system plays an essential role in the mating and reproduction of moths, in which pheromone-binding proteins (PBPs) are crucial genes. In this study, we cloned and purified the protein AlepPBP1 using an E. coli expression system and found it had a higher binding affinity to two sex pheromones of A. lepigone, namely, Z7-12:Ac and Z9-14:Ac (with Ki 0.77 ± 0.10 and 1.10 ± 0.20 µM, respectively), than to other plant volatiles. The binding-mode analysis of protein conformation with equilibrium stabilization was obtained using molecular dynamics (MD) simulation and indicated that hydrophobic interactions involving several nonpolar residues were the main driving force for the binding affinity of AlepPBP1 with sex pheromones. Computational alanine scanning (CAS) was performed to further identify key amino acid residues and validate their binding contributions. Each key residue, including Phe36, Trp37, Val52, and Phe118, was subsequently mutated into alanine using site-directed mutagenesis. Binding assays showed that the efficient binding abilities to Z7-12:Ac (F36A, W37A, and F118A) and Z9-14:Ac (F36A, W37A, V52A, and F118A) were almost lost in the mutated proteins. Our results demonstrated that these key amino acid residues are crucial for determining the binding ability of AlepPBP1 to sex pheromones. These findings provide a basis for the use of AlepPBP1 in the studies as a specific target for the development of novel behavioral antagonists with marked inhibition or mating-disruption abilities using computer-aided drug design (CADD).

Gluconokinase IDNK Promotes Cell Proliferation and Inhibits Apoptosis in Hepatocellular Carcinoma.

PURPOSE: Hepatocellular carcinoma (HCC) is one of the deadliest cancers globally with a poor prognosis. Breakthroughs in the treatment of HCC are urgently needed. This study explored the role of IDNK in the development and progression of HCC. METHODS: IDNK expression was suppressed using short hairpin (shRNA) in BEL-7404 and Huh-7 cells. The expression of IDNK in HCC cells after IDNK knockdown was evaluated by real-time quantitative RT-PCR analysis and Western blot. After IDNK silencing, the proliferation and apoptosis of HCC cells were evaluated by Celigo cell counting, flow cytometry analysis, MTT assay, and caspase3/7 assay. Gene expressions in BEL-7404 cells transfected with IDNK shRNA lentivirus plasmid and blank control plasmid were evaluated by microarray analysis. The differentially expressed genes induced by deregulation of IDNKwere identified, followed by pathway analysis. RESULTS: The expression of IDNK at the mRNA and protein levels was considerably reduced in shRNA IDNK transfected cells. Knockdown of IDNK significantly inhibited HCC cell proliferation and increased cell apoptosis. A total of 1196 genes (585 upregulated and 611 downregulated) were differentially expressed in IDNK knockdown BEL-7404 cells. The pathway of tRNA charging with Z-score = -3 was significantly inhibited in BEL-7404 cells with IDNK knockdown. CONCLUSION: IDNK plays a key role in the proliferation and apoptosis of HCC cells. IDNK may be a candidate therapeutic target for HCC.

Highly Effective and Low-Cost MicroRNA Detection with CRISPR-Cas9.

MicroRNAs have been reported as related to multiple diseases and have potential applications in diagnosis and therapeutics. However, detection of miRNAs remains improvable, given their complexity, high cost, and low sensitivity as of currently. In this study, we attempt to build a novel platform that detects miRNAs at low cost and high efficacy. This detection system contains isothermal amplification, detecting and reporting process based on rolling circle amplification, CRISPR-Cas9, and split-horseradish peroxidase techniques. It is able to detect trace amount of miRNAs from samples with mere single-base specificity. Moreover, we demonstrated that such scheme can effectively detect target miRNAs in clinical serum samples and significantly distinguish patients of non-small cell lung cancer from healthy volunteers by detecting the previously reported biomarker: circulating let-7a. As the first to use CRISPR-Cas9 in miRNA detection, this method is a promising approach capable of being applied in screening, diagnosing, and prognosticating of multiple diseases.

Can Dexmedetomidine Improve Arterial Oxygenation and Intrapulmonary Shunt during One-lung Ventilation in Adults Undergoing Thoracic Surgery? A Meta-analysis of Randomized, Placebo-controlled Trials.

BACKGROUND: One-lung ventilation (OLV) is a common ventilation technology during thoracic surgery that can cause serious clinical problems. We aimed to conduct a meta-analysis to compare oxygenation and intrapulmonary shunt during OLV in adults undergoing thoracic surgery with dexmedetomidine (Dex) versus placebo to assess the influence and safety of using Dex. METHODS: Randomized controlled trials comparing lung protection in patients who underwent thoracic surgery with Dex or a placebo were retrieved from PubMed, EMBASE, MEDLINE, Cochrane Library, and China CNKI database. The following information was extracted from the paper: arterial oxygen partial pressure (PaO2), PaO2/inspired oxygen concentration (PaO2/FiO2, oxygenation index [OI]), intrapulmonary shunt (calculated as Qs/Qt), mean arterial pressure (MAP), heart rate (HR), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, superoxide dismutase (SOD), and malondialdehyde (MDA). RESULTS: Fourteen randomized controlled trials were included containing a total of 625 patients. Compared with placebo group, Dex significantly increased PaO2/FiO2(standard mean difference [SMD] = 0.98, 95% confidence interval [CI] [0.72, 1.23], P < 0.00001). Besides, Qs/Qt (SMD= -1.22, 95% CI [-2.20, -0.23], P = 0.020), HR (SMD= -0.69, 95% CI [-1.20, 0.17], P = 0.009), MAP (SMD= -0.44, 95% CI [-0.84, 0.04], P = 0.030), the concentrations of TNF-α (SMD = -1.55, 95% CI [-2.16, -0.95], P <0.001), and IL-6 (SMD = -1.53, 95% CI [-2.37, -0.70], P = 0.0003) were decreased in the treated group, when compared to placebo group. No significant difference was found in MDA (SMD = -1.14, 95% CI [-3.48, 1.20], P = 0.340) and SOD (SMD = 0.41, 95% CI [-0.29, 1.10], P = 0.250) between the Dex group and the placebo group. Funnel plots did not detect any significant publication bias. CONCLUSIONS: Dex may improve OI and reduce intrapulmonary shunt during OLV in adults undergoing thoracic surgery. However, this conclusion might be weakened by the limited number of pooled studies and patients.

Postoperative serum thioredoxin concentrations correlate with delirium and cognitive dysfunction after hip fracture surgery in elderly patients.

BACKGROUND: Oxidative stress correlates with occurrence and development of postoperative delirium (POD) and cognitive dysfunction (POCD). Thioredoxin (TRX) is a potent anti-oxidant and its circulating concentrations reflect extent of brain injury. We determined the relation of serum TRX concentrations to POD and POCD in elderly patients undergoing hip fracture surgery. METHODS: In this prospective, observatory study, TRX concentrations in preoperative and postoperative serum from 192 patients and serum from 192 controls were measured using an enzyme-linked immunosorbent assay. The relationship between TRX concentrations and risk of POD and POCD was assessed using a multivariate analysis. RESULTS: As compared to the controls, postoperative, but not preoperative serum TRX concentrations were significantly increased in the patients. Furthermore, postoperative TRX concentrations and age were identified as the independent predictors for POD and POCD. Also, area under receiver operating characteristic curve (AUC) of postoperative TRX concentrations was obviously higher than that of age in the prediction of POD and POCD. Additionally, in a combined logistic-regression model, TRX concentrations significantly improved the AUCs of age to predict POD and POCD. CONCLUSIONS: TRX in postoperative serum may be a potential biomarker to predict POD and POCD in elder patients undergoing hip fracture surgery.

The RING finger protein NtRCP1 is involved in the floral transition in tobacco (Nicotiana tabacum).

The transition from the vegetative phase to the reproductive phase is a major developmental process in flowering plants. The underlying mechanism controlling this cellular process remains a research focus in the field of plant molecular biology. In the present work, we identified a gene encoding the C3H2C3-type RING finger protein NtRCP1 from tobacco BY-2 cells. Enzymatic analysis demonstrated that NtRCP1 is a functional E3 ubiquitin ligase. In tobacco plants, expression level of NtRCP1 was higher in the reproductive shoot apices than in the vegetative ones. NtRCP1-overexpressing plants underwent a more rapid transition from the vegetative to the reproductive phase and flowered markedly earlier than the wild-type control. Histological analysis revealed that the shoot apical meristem of NtRCP1-overexpressing plants initiated inflorescence primordia precociously compared to the wild-type plant due to accelerated cell division. Overexpression of NtRCP1 in BY-2 suspension cells promoted cell division, which was a consequence of the shortened G2 phase in the cell cycle. Together, our data suggest that NtRCP1 may act as a regulator of the phase transition, possibly through its role in cell cycle regulation, during vegetative/reproductive development in tobacco plant.

Functional Genetic Variations at the microRNA Binding-Site in the CD44 Gene Are Associated with Risk of Colorectal Cancer in Chinese Populations.

CD44 as one of the most putative stem cell markers plays a key role in many cellular processes, including cancer cell growth and migration. Functional single nucleotide polymorphisms (SNPs) of CD44 may modulate its gene functions and thus cancer risk. In the current study, we investigated if polymorphisms in the 3'-untranslated region (UTR) of CD44 are associated with increased susceptibility to colorectal cancer (CRC) by conducting a case-control study of 946 CRC patients and 989 cancer-free controls. Three polymorphisms (rs13347C/T, rs10836347C/T, rs11821102G/A) in the 3'-UTR of CD44 were genotyped. We found that the variant genotypes (CT and TT) of rs13347 (adjusted odds ratio (OR)=1.79, 95% confidence interval (CI)=1.50-2.17) increased an individual's susceptibility to CRC, compared with rs13347CC homozygous genotypes. We also found that CRC patients with the CT/TT genotype had a 1.6-fold increased risk for developing advanced (stage III + IV) CRC. Furthermore, functional assays showed that the C to T base change at rs13347C/T disrupts the binding site for the microRNA hsa-mir-509-3p, thereby increasing CD44 transcriptional activity and expression level. These findings suggest that the rs13347C/T in microRNA binding site may be potential biomarkers for genetic susceptibility to CRC.

Cotton major latex protein 28 functions as a positive regulator of the ethylene responsive factor 6 in defense against Verticillium dahliae.

In this study, we identified a defense-related major latex protein (MLP) from upland cotton (designated GhMLP28) and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton plants, with higher accumulation in the root. Expression of the GhMLP28 gene was induced by Verticillium dahliae inoculation and was responsive to defense signaling molecules, including ethylene, jasmonic acid, and salicylic acid. Knockdown of GhMLP28 expression by virus-induced gene silencing resulted in increased susceptibility of cotton plants to V. dahliae infection, while ectopic overexpression of GhMLP28 in tobacco improved the disease tolerance of the transgenic plants. Further analysis revealed that GhMLP28 interacted with cotton ethylene response factor 6 (GhERF6) and facilitated the binding of GhERF6 to GCC-box element. Transient expression assay demonstrated that GhMLP28 enhanced the transcription factor activity of GhERF6, which led to the augmented expression of some GCC-box genes. GhMLP28 proteins were located in both the nucleus and cytoplasm and their nuclear distribution was dependent on the presence of GhERF6. Collectively, these results demonstrate that GhMLP28 acts as a positive regulator of GhERF6, and synergetic actions of the two proteins may contribute substantially to protection against V. dahliae infection in cotton plants.

Ectopic expression of a bacterium NhaD-type Na+/H+ antiporter leads to increased tolerance to combined salt/alkali stresses.

AaNhaD, a gene isolated from the soda lake alkaliphile Alkalimonas amylolytica, encodes a Na(+) /H(+) antiporter crucial for the bacterium's resistance to salt/alkali stresses. However, it remains unknown whether this type of bacterial gene may be able to increase the tolerance of flowering plants to salt/alkali stresses. To investigate the use of extremophile genetic resources in higher plants, transgenic tobacco BY-2 cells and plants harboring AaNhaD were generated and their stress tolerance was evaluated. Ectopic expression of AaNhaD enhanced the salt tolerance of the transgenic BY-2 cells in a pH-dependent manner. Compared to wild-type controls, the transgenic cells exhibited increased Na(+) concentrations and pH levels in the vacuoles. Subcellular localization analysis indicated that AaNhaD-GFP fusion proteins were primarily localized in the tonoplasts. Similar to the transgenic BY-2 cells, AaNhaD-overexpressing tobacco plants displayed enhanced stress tolerance when grown in saline-alkali soil. These results indicate that AaNhaD functions as a pH-dependent tonoplast Na(+) /H(+) antiporter in plant cells, thus presenting a new avenue for the genetic improvement of salinity/alkalinity tolerance.

The tobacco BLADE-ON-PETIOLE2 gene mediates differentiation of the corolla abscission zone by controlling longitudinal cell expansion.

The BLADE-ON-PETIOLE (BOP) genes of Arabidopsis (Arabidopsis thaliana) have been shown to play an essential role in floral abscission by specializing the abscission zone (AZ) anatomy. However, the molecular and cellular mechanisms that underlie differentiation of the AZ are largely unknown. In this study, we identified a tobacco (Nicotiana tabacum) homolog of BOP (designated NtBOP2) and characterized its cellular function. In tobacco plants, the NtBOP2 gene is predominantly expressed at the base of the corolla in an ethylene-independent manner. Both antisense suppression of NtBOP genes and overexpression of NtBOP2 in tobacco plants caused a failure in corolla shedding. Histological analysis revealed that the differentiation of the corolla AZ was blocked in the transgenic flowers. This blockage was due to uncontrolled cell elongation at the region corresponding to wild-type AZ. The role of NtBOP2 in regulating cell elongation was further demonstrated in Bright Yellow 2 single cells: perturbation of NtBOP2 function by a dominant negative strategy led to the formation of abnormally elongated cells. Subcellular localization analysis showed that NtBOP2-green fluorescent protein fusion proteins were targeted to both the nucleus and cytoplasm. Yeast two-hybrid, firefly luciferase complementation imaging, and in vitro pull-down assays demonstrated that NtBOP2 proteins interacted with TGA transcription factors. Taken together, these results indicated that NtBOP2 mediated the differentiation of AZ architecture by controlling longitudinal cell growth. Furthermore, NtBOP2 may achieve this outcome through interaction with the TGA transcription factors and via an ethylene-independent signaling pathway.

Impact of hypoxic preconditioning on apoptosis and its possible mechanism in orthotopic liver autotransplantation in rats.

BACKGROUND: Hepatocyte apoptosis is a severe form of cell death after hepatic ischemia-reperfusion injury (HIRI), and its relief is an important issue in liver transplantation. Hypoxic preconditioning (HP) is considered to have protective effects on HIRI. This study was designed to explore the impact of HP on apoptosis and its possible mechanism during orthotopic liver autotransplantation. METHODS: A modified orthotopic liver autotransplantation model was used to simulate HIRI. Sprague-Dawley rats were randomly divided into normal control, autotransplantation (AT) and HP groups. The HP group was subjected to an 8% oxygen atmosphere for 90 minutes before surgery. At 1, 6 and 24 hours after surgery, the rats were killed and their liver tissue was sampled to assess the expression of Bcl-2 protein. The samples were subjected to blood chemistry study, morphological study under a light or transmission electron microscope, and quantitative study of mitochondria. RESULTS: The serum levels of ALT and AST in the HP group were lower than those in the AT group at 1, 6 and 24 hours after orthotopic liver autotransplantation (P<0.05). Bcl-2 protein expression was increased in the HP group at each measurement point (P<0.05). Light microscopy showed that hepatic injury in the AT group was much more severe than in the HP group. Hepatocytes in the AT group showed typical apoptosis signs under a transmission electron microscope. The ultrastructural appearance of hepatocytes in the HP group was much better than in the AT group, and the area, perimeter and diameter of the mitochondria were smaller in the HP group than in the AT group (P<0.05). CONCLUSIONS: Hepatocytes sense and respond to decreased tissue oxygenation. Stimulation by HP relieves apoptosis by upregulating expression of Bcl-2 protein and its protection of mitochondria after orthotopic liver autotransplantation.

[Cloning and characterization of an harpin-encoding gene from Xanthomonas axonopodis pv. glycines required for hypersensitive response on nonhost plant tobacco].

An hpa1 gene was cloned into an expression vector, pET30a(+), from the genomic DNA of Xanthomonas axonopodis pv. glycines (Xag), the causal agent of soybean bacterial pustule, with degenerated primers by polymerase amplification reaction (PCR). The gene product was extracted from the conjugate (BHR-3) of BL21 (DES) with the recombined vector pHR3 after the engineering strain was induced by IPTG in LB medium. The SDS-PAGE gel showed that the gene product was 15.1kD. The product was heat-stable (10 min at 100 degrees C), protease K sensitive, and able to trigger hypersensitive response (HR) in common tobacco, but was unable to elicit HR in NahG transgenic tobacco in which salicylic acid accumulation was abolished. Moreover, the HR elicitation of the protein in tobacco was dispelled by eukayotic metabolic inhibitors, actinomycin D, cycloheximide and LaCl3. The 402 bp hpa1 gene in this study putatively encoded a 133 ammonia acid protein of which glycine (G) was rich with 21.1%. Sequence comparison indicated that the hpa1 gene and its protein was 51.4% - 93.8% identity with those of Xanthomonas oryzae pv. oryzae and other Xanthomonas species and pathovars. Alignments of harpin proteins of Xanthomonas genus displayed that the glycine-rich region with GGG-GG motif was variable. The comparison also showed that the harpin-encoding gene of Xag (nominated here as hpa1(Xag)) did not possess any similarity with that of Erwinia amylovora, Pseudomonas syringae and Ralstonia solanacearum at nucleotide and protein levels. It is concluded that hpa1(Xag) gene encodes an harpin protein which elicits a typical HR in nonhost tobacco.