The impact of arbuscular mycorrhizal fungi and endophytic bacteria on peanuts under the combined pollution of cadmium and microplastics.

It remains unclear how symbiotic microbes impact the growth of peanuts when they are exposed to the pollutants cadmium (Cd) and microplastics (MPs) simultaneously. This study aimed to investigate the effects of endophytic bacteria Bacillus velezens SC60 and arbuscular mycorrhizal fungus Rhizophagus irregularis on peanut growth and rhizosphere microbial communities in the presence of Cd at 40 (Cd40) or 80 (Cd80) mg kg-1 combined without MP or the presence of low-density polyethylene (LDPE) and poly butyleneadipate-co-terephthalate (PBAT). This study assessed soil indicators, plant parameters, and Cd accumulation indicators. Results showed that the application of R. irregularis and B. velezens significantly enhanced soil organic carbon and increased Cd content under the conditions of Cd80 and MPs co-pollution. R. irregularis and B. velezens treatment increased peanut absorption and the enrichment coefficient for Cd, with predominate concentrations localized in the peanut roots, especially under combined pollution by Cd and MPs. Under treatments with Cd40 and Cd80 combined with PBAT pollution, soil microbes Proteobacteria exhibited a higher relative abundance, while Actinobacteria showed a higher relative abundance under treatments with Cd40 and Cd80 combined with LDPE pollution. In conclusion, under the combined pollution conditions of MPs and Cd, the co-treatment of R. irregularis and B. velezens effectively immobilized Cd in peanut roots, impeding its translocation to the shoot.

Mesenchymal stem cell-derived extracellular vesicles in skin wound healing: roles, opportunities and challenges.

Skin wounds are characterized by injury to the skin due to trauma, tearing, cuts, or contusions. As such injuries are common to all human groups, they may at times represent a serious socioeconomic burden. Currently, increasing numbers of studies have focused on the role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in skin wound repair. As a cell-free therapy, MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy. Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures, including the regeneration of vessels, nerves, and hair follicles. In addition, MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization, wound angiogenesis, cell proliferation, and cell migration, and by inhibiting excessive extracellular matrix production. Additionally, these structures can serve as a scaffold for components used in wound repair, and they can be developed into bioengineered EVs to support trauma repair. Through the formulation of standardized culture, isolation, purification, and drug delivery strategies, exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair. In conclusion, MSC-derived EVs-based therapies have important application prospects in wound repair. Here we provide a comprehensive overview of their current status, application potential, and associated drawbacks.

The marriage of immunomodulatory, angiogenic, and osteogenic capabilities in a piezoelectric hydrogel tissue engineering scaffold for military medicine.

BACKGROUND: Most bone-related injuries to grassroots troops are caused by training or accidental injuries. To establish preventive measures to reduce all kinds of trauma and improve the combat effectiveness of grassroots troops, it is imperative to develop new strategies and scaffolds to promote bone regeneration. METHODS: In this study, a porous piezoelectric hydrogel bone scaffold was fabricated by incorporating polydopamine (PDA)-modified ceramic hydroxyapatite (PDA-hydroxyapatite, PHA) and PDA-modified barium titanate (PDA-BaTiO3, PBT) nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. The physical and chemical properties of the Cs/Gel/PHA scaffold with 0-10 wt% PBT were analyzed. Cell and animal experiments were performed to characterize the immunomodulatory, angiogenic, and osteogenic capabilities of the piezoelectric hydrogel scaffold in vitro and in vivo. RESULTS: The incorporation of BaTiO3 into the scaffold improved its mechanical properties and increased self-generated electricity. Due to their endogenous piezoelectric stimulation and bioactive constituents, the as-prepared Cs/Gel/PHA/PBT hydrogels exhibited cytocompatibility as well as immunomodulatory, angiogenic, and osteogenic capabilities; they not only effectively induced macrophage polarization to M2 phenotype but also promoted the migration, tube formation, and angiogenic differentiation of human umbilical vein endothelial cells (HUVECs) and facilitated the migration, osteo-differentiation, and extracellular matrix (ECM) mineralization of MC3T3-E1 cells. The in vivo evaluations showed that these piezoelectric hydrogels with versatile capabilities significantly facilitated new bone formation in a rat large-sized cranial injury model. The underlying molecular mechanism can be partly attributed to the immunomodulation of the Cs/Gel/PHA/PBT hydrogels as shown via transcriptome sequencing analysis, and the PI3K/Akt signaling axis plays an important role in regulating macrophage M2 polarization. CONCLUSION: The piezoelectric Cs/Gel/PHA/PBT hydrogels developed here with favorable immunomodulation, angiogenesis, and osteogenesis functions may be used as a substitute in periosteum injuries, thereby offering the novel strategy of applying piezoelectric stimulation in bone tissue engineering for the enhancement of combat effectiveness in grassroots troops.

Prevalence, predictors, and management for balloon uncrossable or undilatable lesions in patients undergoing percutaneous coronary intervention with in-stent restenosis chronic total occlusion.

Background: Percutaneous coronary intervention for in-stent restenosis (ISR) chronic total occlusion (CTO) has been a great challenge. There are occasions when the balloon is uncrossable or undilatable (BUs) even though the guidewire has passed, leading to failure of the procedure. Few studies have focused on the incidence, predictors, and management of BUs during ISR-CTO intervention. Methods: Patients with ISR-CTO were recruited consecutively between January 2017 and January 2022 and divided into two groups based on the presence of BUs. The clinical data of the two groups (BUs group and non-BUs group) were retrospectively analyzed and compared to explore the predictors and clinical management strategies of BUs. Results: A total of 218 patients with ISR-CTO were included in this study, 23.9% (52/218) of whom had BUs. The percentage of ostial stents, stent length, CTO length, the presence of proximal cap ambiguity, moderate to severe calcification, moderate to severe tortuosity, and J-CTO score were higher in the BUs group than in the non-BUs group (p < 0.05). The technical success rate and the procedural success rate were lower in the BUs group than in the non-BUs group (p < 0.05). Multivariable logistic regression analysis showed that ostial stents (OR: 2.011, 95% CI: 1.112-3.921, p = 0.031), the presence of moderate to severe calcification (OR: 3.383, 95% CI: 1.628-5.921, p = 0.024) and moderate to severe tortuosity (OR: 4.816, 95% CI: 2.038-7.772, p = 0.033) were independent predictors of BUs. Conclusion: The initial rate of BUs in ISR-CTO was 23.9%. Ostial stents, presence of moderate to severe calcification, and moderate to severe tortuosity were independent predictors of BUs.

Interventions and strategies to prevent medical device-related pressure injury in adult patients: A systematic review.

BACKGROUND: Current evidence shows that medical device-related pressure injury (MDRPI) has a high prevalence (10%) and incidence (12%), and much research has been done to prevent MDRPI in recent years. However, to our knowledge, there is limited systematic review available on interventions and strategies to prevent MDRPI. AIM: To synthesise research evidence on interventions and strategies used to prevent MDRPI. METHODS: This systematic review adhered to the PRISMA Guidelines. We searched six databases including Medline, CINAHL, EMBASE, Cochrane library, Web of Science and ProQuest with no restriction to year of publication. Data were extracted and checked by two authors independently. A narrative summary technique was used to describe the findings. Implementation strategies were grouped into six classifications: dissemination/implementation process/integration/capacity building/sustainability/scale-up strategies. RESULTS: Twenty-four peer-reviewed papers met the inclusion criteria, which comprised of 11 quality improvement projects and 13 original research. Types of devices included respiratory devices (non-invasive ventilation mask, CPAP/BiPAP mask, endotracheal tube), gastrointestinal/urinary devices and other devices. Interventions used included the use of dressing, hyperoxygenated fatty acids, full-face mask, training, and/or multidisciplinary education, use of special securement devices or tube holder, repositioning, application of stockinette, early removal and foam ring use. Common implementation strategies included ongoing staff education, audit and standardising documentation or guideline development. CONCLUSION: Much work on MDRPI prevention strategies has been undertaken. There were a variety of devices reported, however, it is evident that higher quality research is needed. RELEVANCE TO CLINICAL PRACTICE: Current evidence shows that interventions including use of dressing or special securement device, repositioning, and training/multidisciplinary education can be beneficial for MDRPI prevention. High-quality research, such as randomised controlled trials are needed to test the effectiveness of the interventions and their implementation strategies. No patient or public contribution.

The Effectiveness of a Self-management Program of Bowel Dysfunction in Patients With Mid and Low Rectal Cancer After Sphincter-Preserving Surgery: A Pilot Randomized Controlled Trial.

BACKGROUND: Most patients with mid and low rectal cancer passively react to bowel symptoms after sphincter-preserving surgery (SPS), and their self-management behaviors are scarce in the Chinese patient population. OBJECTIVE: The aim of this study was to evaluate the effect of a self-management program for bowel symptoms in patients with mid and low rectal cancer after SPS. METHODS: A convenient sampling method was used to recruit patients with mid and low rectal cancer after SPS in gastric wards from 2 tertiary hospitals in Beijing, China. Ninety-five patients (intervention, n = 47; control, n = 48) were recruited. The intervention group received a predetermined self-management program plus routine postoperative care; the control group received only routine care in the ward. Data on patients' bowel symptoms, quality of life, and bowel symptom self-management behaviors were collected at baseline and at 3 and 6 months postoperatively using questionnaires. A generalized estimating equation was adopted to examine group effect and time effect. RESULTS: Bowel symptoms and quality of life in both the intervention and control groups of patients improved significantly 6 months after SPS compared with baseline (time effect, P < .001). The total score of patients' bowel symptom self-management behaviors and the score of the therapeutic domain increased significantly in the intervention group compared with those in the control group (group effect, P = .009). CONCLUSIONS: Self-management programs could help prompt patients' self-management behaviors, but the extent to which they impact patients' bowel symptoms requires further investigation. IMPLICATIONS FOR PRACTICE: The bowel dysfunction self-management program could alter the behavior of patients. It also effectively improves self-management strategies for bowel symptoms.

Electrochemical C-H phosphorylation of arenes in continuous flow suitable for late-stage functionalization.

The development of efficient and sustainable methods for carbon-phosphorus bond formation is of great importance due to the wide application of organophosphorus compounds in chemistry, material sciences and biology. Previous C-H phosphorylation reactions under nonelectrochemical or electrochemical conditions require directing groups, transition metal catalysts, or chemical oxidants and suffer from limited scope. Herein we disclose a catalyst- and external oxidant-free, electrochemical C-H phosphorylation reaction of arenes in continuous flow for the synthesis of aryl phosphorus compounds. The C-P bond is formed through the reaction of arenes with anodically generated P-radical cations, a class of reactive intermediates remained unexplored for synthesis despite intensive studies of P-radicals. The high reactivity of the P-radical cations coupled with the mild conditions of the electrosynthesis ensures not only efficient reactions of arenes of diverse electronic properties but also selective late-stage functionalization of complex natural products and bioactive compounds. The synthetic utility of the electrochemical method is further demonstrated by the continuous production of 55.0 grams of one of the phosphonate products.

Yunmen (LU 2) combined with neck-seven-acupoint acupuncture for arm numbness caused by cervical spondylotic radiculopathy: A case report.

RATIONALE: Cervical spondylotic radiculopathy (CSR) is a common sensory, motor, and reflex disorder. Numbness, a common subjective symptom of CSR, lacks objective quantitative indicators and recognized effective treatments, but is also difficult to recover from. We present a case report describing a traditional acupuncture treatment for CSR, utilizing a special acupuncture method and point, namely the Yunmen point. PATIENT CONCERNS: A 40-year-old woman presented with unilateral arm numbness caused by CSR. DIAGNOSES: A diagnosis of CSR was made in the orthopedic department of a local hospital. INTERVENTIONS: We attempted acupuncture at the Yunmen (LU 2) acupoint combined with neck-seven-acupoint under computed tomographic guidance. OUTCOMES: After 10 times treatment sessions, the patient no longer experienced weakness, coldness, or numbness in the affected upper limb. In addition, the stiffness in the neck and shoulders was reduced. On physical examination, the patient's left brachial plexus traction test was negative; reassessment of the CSR-20-point score scale showed a perfect score, and the visual analog scale score was 0. LESSONS: Our report indicates that acupuncture at the LU 2 acupoint combined with neck-seven-acupoint is effective in treating numbness and coldness of the arm, and other neurological symptoms caused by cervical spondylosis. Moreover, with the appropriate acupuncture technique, the risk of acupuncture at the LU 2 acupoint can be minimized.

Catalyst- and Reagent-Free Formal Aza-Wacker Cyclizations Enabled by Continuous-Flow Electrochemistry.

The development of efficient and sustainable methods to access saturated N-heterocycles is of great importance because of the prevalence of these structures in natural products and bioactive compounds. Pd-catalyzed aza-Wacker type cyclization is a powerful method and provides access to N-heterocycles bearing an alkene moiety available for further synthetic manipulations from readily available materials. Herein we disclose a catalyst- and reagent-free formal aza-Wacker type cyclization reaction for the synthesis of functionalized saturated N-heterocycles. Key to the success is to conduct the reactions in a continuous-flow electrochemical reactor without adding supporting electrolyte or additives. The reactions are characterized by broad tolerance of di-, tri- and tetrasubstituted alkenes.

Guizhi Decoction () Inhibits Cholinergic Transdifferentiation by Regulating Imbalance of NGF and LIF in Salt-Sensitive Hypertensive Heart Failure Rats.

OBJECTIVE: To observe the imbalance of anatomical and functional innervation factors of sympathetic nerves, nerve growth factor (NGF) and leukemia inhibitory factor (LIF), in salt-sensitive hypertensive heart failure rats and to explore the effects of treatment with Guizhi Decoction () on sympathetic remodeling by inhibiting cholinergic transdifferentiation. METHODS: SS-13BN and Dahl salt-sensitive (DS) rats were divided into 3 groups: SS-13BN group (control group, n=9), DS group (model group, n=9) and GS group (Guizhi Decoction, n=9). After 10 weeks of a high-salt diet, the GS group rats were given Guizhi Decoction and other two groups were given saline at an equal volume as a vehicle. After 4 weeks' intragastric administration, rats were executed to detect the relevant indicators. Echocardiography and plasma n-terminal pro-B type natriuretic peptide (NT-proBNP) levels were used to assess cardiac function. Noradrenaline (NA) levels in the plasma and myocardium were detected to evaluate the sympathetic function. NGF and LIF expression were detected in the myocardium by Western blot or quantitative real-time PCR. Double immunofluorescence or Western blot was used to detect tyrosine hydroxylase (TH), choline acetyltransferase (CHAT) and growth associated protein 43 (GAP43) in order to reflect anatomical and functional changes of sympathetic nerves. RESULTS: DS group had anatomical and functional deterioration of sympathetic nerves in the decompensation period of heart failure compared with SS-13BN group. Compared with the DS group, Guizhi Decoction significantly decreased the expression of LIF mRNA/protein (P<0.01), increased the expression of NGF (P<0.05 or P<0.01), enhanced the levels of TH+/GAP43+ and TH+/CHAT+ positive nerve fibers (P<0.01), and improved the protein expression of TH and GAP43 in left ventricle, but had no effect on CHAT (P>0.05). Guizhi Decoction inhibited inflammatory infiltration and collagen deposition of myocardial injury, increased the content of myocardial NA (P<0.05), reduced the plasma NA level (P<0.01), improved cardiac function (P<0.01), and improved weight and blood pressure to some extent (P<0.05), compared with DS group. CONCLUSIONS: Guizhi Decoction could inhibit cholinergic transdifferentiation of sympathetic nerves, improve the anatomical and functional denervation of sympathetic nerves, and delay the progression of decompensated heart failure. The mechanism may be associated with the correction of the imbalance of NGF and LIF.

Xiao-Qing-Long Tang Prevents Cardiomyocyte Hypertrophy, Fibrosis, and the Development of Heart Failure with Preserved Ejection Faction in Rats by Modulating the Composition of the Gut Microbiota.

BACKGROUND: Changes in the gut microbiota are associated with cardiovascular disease progression. Xiao-Qing-Long Tang (XQLT), a traditional herbal formula, has an anti-inflammatory effect and regulates the steady state of the immune system, which is also associated with the progression of heart failure with preserved ejection faction (HFpEF). In this study, we investigated whether XQLT could contribute to prevent the development of HFpEF and whether the modulation of the gut microbiota by this herbal formula could be involved in such effect. METHODS: The gut microbiota, SCFAs, the histology/function of the heart, and systolic blood pressure were examined to evaluate the effect of XQLT on the gut microbiota and the progression of HFpEF after oral administration of XQLT to model rats. Furthermore, we evaluated, through fecal microbiota transplantation experiments, whether the favorable effects of XQLT could be mediated by the gut microbiota. RESULTS: Oral administration of XQLT contributed to the reduction of elevated blood pressure, inflammation, and compensatory hypertrophy, features that are associated with the progression of HFpEF. The gut microbiota composition, SCFA levels, and intestinal mucosal histology were improved after treatment with XQLT. Moreover, fecal transfer from XQLT-treated rats was sufficient to prevent the progression of HFpEF. CONCLUSIONS: These data suggested that XQLT prevented the development of HFpEF in model rats by regulating the composition of the gut microbiota.

Clinical epidemiological survey of gallbladder carcinoma in northwestern China, 2009-2013: 2379 cases in 17 centers.

OBJECTIVE: To analyze the clinical epidemiological characteristics of patients with gallbladder carcinoma recruited from 17 hospitals in five northwestern provinces of China (Shaanxi Province, Gansu Province, Qinghai Province, Ningxia Hui Autonomous Region, and Xinjiang Uygur Autonomous Region) from 2009 to 2013, and to summarize the clinical diagnosis and treatment data of gallbladder carcinoma. METHODS: Clinical information of 2379 patients with gallbladder carcinoma from 17 hospitals in five northwestern provinces of China was retrospectively collected and analyzed using the "Questionnaire for Gallbladder Carcinoma Patients in Northwestern Area of China." All information was verified with EpiData software and analyzed with SPSS 13.0 software. RESULTS: (1) Gallbladder carcinoma accounted for 2.7% (2379/86,609) of all biliary tract diseases during the study period, which was significantly higher than that from 1986 to 1998 (P < 0.001). (2) Gallbladder carcinoma was more prone to occur in elderly women. The male:female incidence ratio was 1.0:2.1, the average age of onset of disease was 63.7 ± 11.3 years, and the incidence was higher in farmers than in other occupational groups. (3) A total of 57.2% (1360/2379) of patients with gallbladder carcinoma also had gallstones. (4) Abdominal pain (1796/2379, 75.5%) and jaundice (727/2379, 30.6%) were the most common clinical manifestations, 81.2% (1527/1881) were positive in those receiving B ultrasound examinations and 90.7% (1567/1727) were positive in those undergoing computed tomography, and 64.5% (1124/1742) of patients with gallbladder carcinoma were positive for carbohydrate antigen (CA) 19-9. (5) The pathological type of gallbladder carcinoma was mainly moderately and poorly differentiated adenocarcinoma with a high degree of malignancy. At admission, 55.1% (1091/1981) of patients had stage IV cancer among patients with TNM staging information; 55.9% (1331/2379) had lymphatic metastasis, 29.7% (706/2379) had bile duct metastasis, and 53.1% (1263/2379) had liver metastasis. (6) A total of 283 patients (283/2379, 11.9%) had incidentally detected gallbladder carcinoma. (7) The rate of radical surgical resection was 30.4% (723/2379). CONCLUSION: The proportion of gallbladder carcinoma in biliary tract diseases in the northwestern area of China was significantly higher from 2009 to 2013 than from 1986 to 1998. Gallbladder carcinoma was common in older women and mainly diagnosed at an advanced stage. Compared with other surveys in different regions, the rate of metastasis in this survey was high, leading to a low resection rate. Populations at high risk should undergo B-ultrasound examinations at regular follow-up intervals to increase the rate of early diagnosis of gallbladder carcinoma.

cGMP Signalling Mediates Water Sensation (Hydrosensation) and Hydrotaxis in Caenorhabditis elegans.

Animals have developed the ability to sense the water content in their habitats, including hygrosensation (sensing humidity in the air) and hydrosensation (sensing the water content in other microenvironments), and they display preferences for specific water contents that influence their mating, reproduction and geographic distribution. We developed and employed four quantitative behavioural test paradigms to investigate the molecular and cellular mechanisms underlying sensing the water content in an agar substrate (hydrosensation) and hydrotaxis in Caenorhabditis elegans. By combining a reverse genetic screen with genetic manipulation, optogenetic neuronal manipulation and in vivo Ca(2+) imaging, we demonstrate that adult worms avoid the wetter areas of agar plates and hypo-osmotic water droplets. We found that the cGMP signalling pathway in ciliated sensory neurons is involved in hydrosensation and hydrotaxis in Caenorhabditis elegans.

Off-response in ASH neurons evoked by CuSO4 requires the TRP channel OSM-9 in Caenorhabditis elegans.

The off-response of ASH neurons had been overlooked until the microfluidic devices were introduced for in vivo imaging of neuronal activity in Caenorhabditis elegans. The mechanisms of ASH off-response were completely unknown. Here we monitored ASH off-response to CuSO4 stimulation by use of microfluidic device and genetically encoded calcium indicator (GECI) - Case12. We found ASH neurons exhibited a multiphasic response to 10 mM and 50 mM CuSO4 of 30-s stimulation duration. ASH off-responding to Cu(2+) had been dramatically reduced in goa-1, mod-5, trpa-1 and egl-8 mutants. Moreover, in osm-9 mutants ASH off-response was completely eliminated. Neuron-specific rescue of osm-9 in ASH neurons restored the off-response and the normal avoidance behavior in worms.

PKG and NHR-49 signalling co-ordinately regulate short-term fasting-induced lysosomal lipid accumulation in C. elegans.

Lysosomes act as terminal degradation organelles to hydrolyse macromolecules derived from both the extracellular space and the cytoplasm. In Caenorhabditis elegans fasting induces the lysosomal compartment to expand. However, the molecular and cellular mechanisms for this stress response remain largely unclear. In the present study, we find that short-term fasting leads to increased accumulation of polar lipids in lysosomes. The fasting response is co-ordinately regulated by EGL-4, the C. elegans PKG (protein kinase G) orthologue, and nuclear hormone receptor NHR-49. Further results demonstrate that EGL-4 acts in sensory neurons to enhance lysosomal lipid accumulation through inhibiting the DAF-3/SMAD pathway, whereas NHR-49 acts in intestine to inhibit lipids accumulation via activation of IPLA-2 (intracellular membrane-associated calcium-independent phospholipase A2) in cytoplasm and other hydrolases in lysosomes. Remarkably, the lysosomal lipid accumulation is independent of autophagy and RAB-7-mediated endocytosis. Taken together, our results reveal a new mechanism for lysosomal lipid metabolism during the stress response, which may provide new clues for investigations of lysosome function in energy homoeostasis.

Exogenous basic fibroblast growth factor inhibits ER stress-induced apoptosis and improves recovery from spinal cord injury.

AIM: To investigate the mechanism of endoplasmic reticulum (ER) stress-induced apoptosis as well as the protective action of basic fibroblast growth factor (bFGF) both in vivo and in vitro. METHODS AND RESULTS: ER stress-induced apoptosis was involved in the injuries of spinal cord injury (SCI) model rat. bFGF administration improved the recovery and increased the survival of neurons in spinal cord lesions in model rat. The protective effect of bFGF is related to the inhibition of CHOP, GRP78 and caspase-12, which are ER stress-induced apoptosis response proteins. bFGF administration also increased the survival of neurons and the expression of growth-associated protein 43 (GAP43), which is related to neural regeneration. The protective effect of bFGF is related to the activation of downstream signals, PI3K/Akt/GSK-3ß and ERK1/2, especially in the ER stress cell model. CONCLUSIONS: This is the first study to illustrate that the role of bFGF in SCI recovery is related to the inhibition of ER stress-induced cell death via the activation of downstream signals. Our work also suggested a new trend for bFGF drug development in central neural system injuries, which are involved in chronic ER stress-induced apoptosis.

A novel fluorescent timer based on bicistronic expression strategy in Caenorhabditis elegans.

Fluorescent timers are useful tools for studying the spatial and temporal cellular or molecular events. Based on the trans-splicing mechanism in Caenorhabditis elegans, we constructed a "fluorescent timer" through bicistronic expression of two fluorescent proteins with different maturation times. When used in vivo, this "timer" changes its color over time and therefore can be used to monitor the activity of the targeted promoters in C. elegans. Using this "timer", we have successfully traced the time-dependent activity of myo-3 promoter which drives expression in body wall muscle and vulval muscle. We found that the myo-3 promoter started to be active about 7 h after egg-laying and sustained its activity in the following hatching process. We have also determined the myo-3 promoter activity during larval development by this "timer". We anticipate that more new "fluorescent timers" with variable time-resolution could be designed by bicistronic expression of different fluorescent protein pairs.

Fabrication of size-controllable ultrasmall-disk electrode: monitoring single vesicle release kinetics at tiny structures with high spatio-temporal resolution.

Size-controllable micron or nano-disk carbon fiber electrode (CFE) is prepared and demonstrated to be excellent for extra-cellular transmitter release detection at tiny structures and vesicle fusion kinetics analysis with high spatio-temporal resolution. An improved electrochemical etching procedure was employed, for the first time, to fabricate cylindrical fiber with controlled micron or nano-diameter. Afterwards, a facile insulation with polypropylene sheath was employed to completely insulate the whole body of the thinned fiber, and an ultrasmall-disk sensing area was finally produced by cutting of the insulated fibers. Scanning electron microscopy (SEM) was employed to characterize the ultrasmall geometry size of the fabricated electrode and to show the tight adherence of the insulation sheath on the fiber. The cut ends of the electrodes were also shown to be smooth, clean and without obvious jagged layer. The fabricated micron or nano-disk carbon electrodes show ideal steady-state voltammetric behavior with satisfying reversibility. Subsequently, the performance of the ultrasmall-disk CFE for amperometric detection of cell secretion was characterized. Results showed that, compared to the conventional micro-disk CFE, the etched small disk CFE possesses higher sensitivity due to its obviously improved signal-to-noise level, which enables minute amounts of 3000 oxidizable molecules to be detectable. The nano-disk CFE was shown to be particularly ideal for analysis of fusion kinetics, due to its avoidance of diffusion broadening of the detected spikes, which is the inherent defect of the conventional micro-CFE technique.

Overexpression of PEMT2 downregulates the PI3K/Akt signaling pathway in rat hepatoma cells.

Phosphatidylethanolamine N-methyltransferase 2 (PEMT2) is an isoform of PEMT that converts phosphatidylethanolamine to phosphatidylcholine in mammalian liver. Overexpression of PEMT2 led to inhibition of proliferation of hepatoma cells [J. Biol. Chem. 269 (1994) 24531]. The present study aims to unravel the molecular mechanism of the reduced proliferation, especially the signaling transducer proteins involved in this process. Thus, we chose PI3K/Akt pathway that is initiated by growth factors and leads to cell survival and proliferation. Rat hepatoma CBRH-7919 cells transfected with pemt2-cDNA showed that: (1) signaling proteins including c-Met, PDGF receptor, PI3K, Akt and Bcl-2 all had reduced expression as shown by Western blotting studies; (2) flow cytometric and DNA ladder assays showed that 22.9% of the pemt2-transfected cells were undergoing apoptosis; (3) the activity of Akt was decreased as shown by Western blotting using antibody directed against p-Akt (Thr308); (4) wortmannin and PD98059, inhibitors of PI3K and MEK, respectively, both inhibited Akt activity, indicating that PI3K and MAPK pathways were merging at Akt in CBRH-7919 cells. The above results suggest that overexpression of PEMT2 strongly downregulated the PI3K/Akt signaling pathway at multiple sites and induced apoptosis. This, at least partly, explains the molecular mechanism of impaired proliferation induced by pemt2 transfection.