OBJECTIVETo investigate the relationship among oxygen concentration, quorum sensing system, type secretion system, and biofilm production of Pseudomonas aeruginosa.

METHODSA total of 23 clinical strains of Pseudomonas aeruginosa were cultured at different levels of environmental oxygen for three days. Then biofilm mass and alginate were quantified. The expression levels of LasI and RhlI were detected by real time polymerase chain reaction (PCR). The secretion of exoenzyme S was examined by Western blot.

RESULTSBoth the biofilm mass (R=0.455, P=0.000) and alginate (R=0.367, P=0.000) were positively correlated with oxygen concentration. Real time PCR showed that the expression levels of LasI and RhlI were not significantly correlated with oxygen concentration (R=0.025, P=0.794; R=-0.044, P=0.653), the production of biofilm (R=0.001, P=0.990; R=0.011, P=0.909), or alginate(R=0.029, P=0.770; R=0.193, P=0.064). Western blot showed that the optimal oxygen concentration range for exoenzyme S secretion of Pseudomonas aeruginosa ranged 10% to 30%.

CONCLUSIONSHyperoxia can promote the production of biofilm and alginate by Pseudomonas aeruginosa. Las/Rhl system may not participate in biofilm production at the early stage due to the low bacteria amount. The increased production of biofilm may inhibit the expression of Type Secretion system and thus inhibit bacterial virulence.

Alginates ; metabolism ; Biofilms ; drug effects ; Oxygen ; metabolism ; Pseudomonas aeruginosa ; metabolism ; physiology ; Quorum Sensing ; drug effects ; physiology

OBJECTIVETo investigate the effects of nitrogen concentration on the camptothecin (CPT) content in Camptotheca acuminata seedlings:

METHODThe seedlings of C. acuminata with 6 pair of leaves were subjected to five nitrogen concentrations treatments by sand culture in a greenhouse. The CPT content in the seedlings was determined by HPLC on the 20th, 35th, 50th, 65th and 80th day respectively.

RESULTThe CPT content in the young leaves of C. acuminata seedlings supplied with different nitrogen concentration was significantly higher than that in other organs (P < 0.01), and it showed a single peak curve with the time course, the highest CPT content was observed on the 50th day after treatment. The CPT content in the young leaves obviously declined with increasing nitrogen concentration, and it reached the highest (6.72%) when nitrogen concentration was 4 mmol x L(-1), equal to 1.1 times that of 16 mmol x L(-1) nitrogen.

CONCLUSIONThe results demonstrate that proper deficient nitrogen stress can significantly enhance CPT accumulation in young leaves of C. acuminata seedlings.

Camptotheca ; drug effects ; metabolism ; Camptothecin ; metabolism ; Chromatography, High Pressure Liquid ; Nitrogen ; pharmacology ; Seedlings ; drug effects ; metabolism

OBJECTIVETo study the effects of shading on photosynthetic physiology and chlorophyll fluorescence of Pinellia ternata.

METHODPlant growth, chlorophyll content, net photosynthetic rate (P(n)) and chlorophyll fluorescence in P. ternata were investigated under different shading treatments (0%, 70% and 90%) when it grew about 15 cm high.

RESULTThe results showed that fresh weight of a tuber, height, leaf length, width, leaf area, specific leaf area (SLA) and contents of chlorophyll content were enhanced after shaded, and chlorophyll a/b rate declined. Compared with control, net photosynthetic rate, light compensation point (LCP) and light saturation point (LSP) of P. ternata decreased after shading, but apparent quantum yield (AQY) increased; quantum yield of PS II (PhiPS II), minimal fluorescence (F(o)), maximal fluorescence (F(m)), intrinsic photochemical efficiency of PS II (F(v)/F(m)) and photochemical quenching coefficient (qP) were enhanced.

CONCLUSIONCompared with control, all data indicated that there were distinctive differences between the height, SLA, chlorophyll content, P(n) and chlorophyll fluorescence characteristics under the shading treatments (70% and 90%), the fresh weight of a tuber increased after 70% shading, and provided better environmental conditions for the growth of P. ternata.

Chlorophyll ; metabolism ; Light ; Photosynthesis ; drug effects ; Pinellia ; metabolism ; radiation effects ; Plant Leaves ; metabolism ; radiation effects

OBJECTIVEIn order to get the method for improving the salt resistance of Lycium ruthenium seeds and seedlings under NaCl stress, the seed germination and physiological characteristics of L. ruthenium seedlings was studied.

METHODSeveral physiological indexes of L. ruthenium seeds under NaCl stress, such as the germination rate (Gr), germination vigor (Gv), germination index (Gi), vigor index (Vi), and relative salt damage rate were measured. Other indexes of the seedlings like relative water contents (RWC) , chlorophyll contents, soluble protein contents, electrolyte leakage, the contents of malondialdehyde (MDA), and peroxidase (POD) were also measured.

RESULTNaCl at lower concentration could promote the seed germination but inhibit the seed germination at higher concentration. After the treatment by CaCl2 at the different concentrations, all germination indexes were increased. With the increase of salt concentration, the relative water contents and the contents of chlorophyll were decreased, the content of MDA and electrolyte leakage were increased. The change trend of POD activity showed the first increase and then decrease with the increase of salt concentration, which was similar to that of the soluble protein. After the treatment by CaCl2, relative water contents, chlorophyll and POD activities were decreased more slowly, and also electrolyte leakage and MDA contents increased slowly.

CONCLUSIONThe CaCl2 could significantly alleviate the damages to the seeds and seedlings of L. ruthenium under NaCl stress, and promote the salt resistance to the seeds and seedlings of L. ruthenium.

Calcium ; pharmacology ; Germination ; drug effects ; Lycium ; drug effects ; metabolism ; physiology ; Seedlings ; drug effects ; metabolism ; physiology ; Seeds ; drug effects ; metabolism ; physiology ; Sodium Chloride ; metabolism

OBJECTIVETo study the effects of extremely low frequency electromagnetic field(ELF EMF) and its combination with lead on the antioxidant system in mouse brain and liver tissues.

METHODMice were exposed to a 50 Hz sinusoidal 0.2 mT or 6.0 mT EMF for 2 weeks. At the same time, some groups were exposed to lead(50 mg/kg). After the exposure, the antioxidant system and cell membrane fluidity in brain and liver were measured.

RESULTSMalondiadehyde(MDA) content in brain and liver increased from the control levels of (1.33 +/- 0.12) and (3.95 +/- 0.21) nmol/mg pro to (1.35 +/- 0.09) and (6.15 +/- 0.28) nmol/mg pro respectively following 0.2 mT exposure, and to (3.98 +/- 0.10) and (6.50 +/- 0.79) nmol/mg pro respectively following 6.0 mT exposure. Total antioxidant capability(T-AOC) in brain and liver decreased from the control levels of (4.39 +/- 0.48) and (2.45 +/- 0.21) U/mg pro to (3.99 +/- 0.39) and (1.92 +/- 0.32) U/mg pro respectively following 0.2 mT, and to (3.12 +/- 0.37) and (1.57 +/- 0.14) U/mg pro respectively following 6.0 mT. GSH content decreased only in liver tissue from the control level of (194.60 +/- 20.93) mg/g pro to (189.24 +/- 5.61) mg/g pro(0.2 mT) and (153.04 +/- 1.18) mg/g pro(6.0 mT). Cellular membrane fluidity decreased from the control levels of (1.396 +/- 0.040) and (2.899 +/- 0.552) to (1.224 +/- 0.190) and (1.894 +/- 0.0761) (0.2 mT), (1.159 +/- 0.179) and (1.516 +/- 0.204)(6.0 mT) respectively. Compared with single EMF exposure(6.0 mT), EMF combined with lead exposure induced remarkable increase in MDA, GSH content and T-AOC and decrease in cell membrane fluidity both in the brain and liver, and increase in SOD activity only in liver.

CONCLUSIONELF EMF might alter the metabolism of free radicals, decrease anti-oxidant capability and enhance lipid peroxidation. The combination of EMF with lead showed synergic effects on lipid peroxidation.

Animals ; Antioxidants ; metabolism ; Brain ; drug effects ; metabolism ; radiation effects ; Electromagnetic Fields ; adverse effects ; Glutathione ; analysis ; Lead ; toxicity ; Lipid Peroxidation ; drug effects ; radiation effects ; Liver ; drug effects ; metabolism ; radiation effects ; Membrane Fluidity ; drug effects ; radiation effects ; Mice ; Superoxide Dismutase ; metabolism

Animals ; Arsenates ; toxicity ; Female ; Kidney ; drug effects ; Lipid Metabolism ; drug effects ; Liver ; drug effects ; Oxidative Stress ; drug effects ; Rats, Wistar

OBJECTIVETo investigate the effects of activated AKT on murine myeloid precursor cells (32D cells), and the effects of IFN-γ on 32D cells and its mechanisms.

METHODSPlasmid transduction was used to enhance the expression of AKT on 32D cells. After the transfected cells treated with IFN-γ for 24 hours, proliferation rate was tested by WST-1, apoptosis by flow cytometry, expression of phosphorylated Erk1/2, Stat3 and phosphorylated Stat3 was determined by Western blot.

RESULTS(1) IFN-γ at low concentration (100 U/ml) enhanced the growth and proliferation of 32D cells, while at high concentration (1000 U/ml) suppressed them. (2) Compared with control groups, low concentration IFN-γ increased (1124 ± 13) Stat3 phosphorylation in 32D-cell, while it high concentration IFN-γ decreased (601 ± 13). 32D cells transfected with activated Akt grew rapidly (0.287 ± 0.010) and had a low apoptotic rate [(9.57 ± 0.17)% (P < 0.05)]. (3) The expression of p-Erk1/2 in transfected 32D-cell was significantly reduced (P < 0.05). (4) Apoptosis rate of IFN-γ treated group was significantly decreased in transfected 32D cells (P < 0.05).

CONCLUSIONSIFN-γ has dual effects on 32D cells, namely, at low concentration enhanced the growth and proliferation of 32D cells, while at high concentration suppressed them. Its mechanisims is possibly through Stat3 pathway. Activated Akt can significantly promote the growth and proliferation of 32D cell and significantly inhibit apoptosis and IFN-γ can regulate cell proliferation and apoptosis through AKT. AKT activation can inhibit the Erk signal pathway, which may be affected by inhibition the modificaton of Raf1.

Animals ; Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Phosphorylation ; drug effects ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; drug effects

OBJECTIVETo observe the effect of curcumin on the expression of Abeta42 and its degrading enzyme NEP in APP/PS1 double transgenic mice.

METHOD3-month old APP/PS1 dtg mice were randomly divided into model group, positive control group and curcumin large, medium and small dose group. After 3 months, Morris water maze, immunohistochemistry, Western blot were applied to detect learning and memory ability of animal.

RESULTBehavior detection, compared with the model group, treatment group showed varying degrees of difference in place navigation test and space exploration experiments (P < 0.01 or P < 0.05). The expression of Abeta42 and its degrading enzyme NEP, Abeta42-positive cells of hippocampus CA1 region significantly increased in model mice as compared with normal control group (P < 0.01).

CONCLUSIONCurcumin can improve learning and memory ability of APP/PS1 double transgenic mice through increasing the expression of Abeta-degrading enzyme NEP and decreasing the expression of Abeta42.

Amyloid beta-Peptides ; drug effects ; metabolism ; Animals ; CA1 Region, Hippocampal ; drug effects ; metabolism ; Curcumin ; pharmacology ; DNA-Directed RNA Polymerases ; drug effects ; metabolism ; Maze Learning ; drug effects ; Memory ; drug effects ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Peptide Fragments ; drug effects ; metabolism

OBJECTIVETo compare the effect of three preparations of xiaoyao formula (xiaoyao capsule, xiaoyao pill and Xiaoyao decoction) on soothing liver and strengthening spleen.

METHODThe liver depression and spleen deficiency rat model were established by forcing swimming, confining movement test and feeding on alternate days. The rats were randomly divided into eight groups, namely the blank group, the model group, the Cisapride group (2.7 mg x kg(-1)), the xiaoyao decoction group (1.62 g x kg(-1)), the xiaoyao pill group (1.62 g x kg(-1)) and the Xiaoyao capsule groups of high dose (3.24 g x kg(-1)), medium dose (1.62 g x kg(-1)) and low dose (0.81 g x kg(-1)), with intragastric administration for 3 weeks. The contents of NE, DA, 5-HT in serum were measured by HPLC-electrochemical detection method. The contents of motilin (MTL) and somatostation (SS) in plasma was determined by radioimmunassay. The expressions of MTL and SS in tissue were determined by immunohistochemical method.

RESULTThe contents of NE and MTL in the xiaoyao decoction group was significantly higher than that in the model group, while the content of 5-HT and SS was significantly lower than that in the model group (P < 0.01). The expression of MTL in the xiaoyao capsule group (1.62 g x kg(-1)) was significantly higher than that in the model group and the contents of 5-HT and SS was significantly lower than that in the model group (P < 0.05). The mean optical density of MTL in gastrointestinal tissue of rats in the xiaoyao decoction group and the xiaoyao capsule group (1.62 g x kg(-1)) was remarkably higher than that in the model group, while the expression of SS was notably lower than that in the model group (P < 0.05).

CONCLUSIONAll of the three preparations of Xiaoyao formula have the effect on soothing liver and strengthening spleen. Xiaoyao decoction shows better effect than xiaoyao capsule with same dosage, while xiaoyao capsule shows better effect than xiaoyao pill with same dosage.

Animals ; Body Weight ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Intestines ; drug effects ; metabolism ; Liver ; drug effects ; metabolism ; Male ; Motilin ; metabolism ; Rats ; Somatostatin ; metabolism ; Spleen ; drug effects ; metabolism ; Stomach ; drug effects ; metabolism

Ca2+ at 1.64 mmol/L markedly increased ethanol tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae. After 9 h of exposure to 20% (V/V) ethanol at 30 degrees C , no viability remained for the control whereas 50.0% remained for the cells both grown and incubated with ethanol in Ca2+ -added medium. Furthermore, when subjected to 15% (V/V) ethanol at 30 degrees C, the equilibrium nucleotide concentration and plasma membrane permeability coefficient (P' ) of the cells both grown and incubated with ethanol in Ca2+ -added medium accounted for only 50.0% and 29.3% those of the control respectively, indicating that adding Ca2+ can markedly reduce plasma membrane permeability of yeast cells under ethanol stress as compared with the control. Meanwhile, high viability levels acquired by the addition of Ca2+ exactly corresponded to the striking decreases in extracellular nucleotide concentration and P' achieved with identical approach. Therefore, the enhancing effect of Ca2+ on ethanol tolerance of this strain is closely related to its ability to decrease plasma membrane permeability of yeast cells subjected to ethanol stress.
Calcium ; pharmacology ; Cell Membrane ; drug effects ; metabolism ; Cell Membrane Permeability ; drug effects ; Ethanol ; pharmacology ; Saccharomyces cerevisiae ; drug effects ; growth & development ; metabolism ; Schizosaccharomyces ; drug effects ; growth & development ; metabolism ; Temperature