Thioredoxin interacting protein drives astrocytic glucose hypometabolism in corticosterone-induced depressive state.

Brain energetics disturbance is a hypothesized cause of depression. Glucose is the predominant fuel of brain energy metabolism; however, the cell-specific change of glucose metabolism and underlying molecular mechanism in depression remains unclear. In this study, we firstly applied 18 F-FDG PET and observed brain glucose hypometabolism in the prefrontal cortex (PFC) of corticosterone-induced depression of rats. Next, astrocytic glucose hypometabolism was identified in PFC slices in both corticosterone-induced depression of rats and cultured primary astrocytes from newborn rat PFC after stress-level corticosterone (100 nM) stimulation. Furthermore, we found the blockage of glucose uptake and the decrease of plasma membrane (PM) translocation of glucose transporter 1 (GLUT1) in astrocytic glucose hypometabolism under depressive condition. Interestingly, thioredoxin interacting protein (TXNIP), a glucose metabolism sensor and controller, was found to be over-expressed in corticosterone-stimulated astrocytes in vivo and in vitro. High TXNIP level could restrict GLUT1-mediated glucose uptake in primary astrocytes in vitro. Adeno-associated virus vector-mediated astrocytic TXNIP over-expression in rat medial PFC suppressed GLUT1 PM translocation, consequently developed depressive-like behavior. Conversely, TXNIP siRNA facilitated GLUT1 PM translocation to recover glucose hypometabolism in corticosterone-exposed cultured astrocytes. Notably, astrocyte-specific knockdown of TXNIP in medial PFC of rats facilitated astrocytic GLUT1 PM translocation, showing obvious antidepressant activity. These findings provide a new astrocytic energetic perspective in the pathogenesis of depression and, more importantly, provide TXNIP as a promising molecular target for novel depression therapy.

Atractylodin inhibits fructose-induced human podocyte hypermotility via anti-oxidant to down-regulate TRPC6/p-CaMK4 signaling.

High fructose has been reported to drive glomerular podocyte oxidative stress and then induce podocyte foot process effacement in vivo, which could be partly regarded as podocyte hypermotility in vitro. Atractylodin possesses anti-oxidative effect. The aim of this study was to explore whether atractylodin prevented against fructose-induced podocyte hypermotility via anti-oxidative property. In fructose-exposed conditionally immortalized human podocytes, we found that atractylodin inhibited podocyte hypermotility, and up-regulated slit diaphragm proteins podocin and nephrin, and cytoskeleton protein CD2-associated protein (CD2AP), α-Actinin-4 and synaptopodin expression, which were consistent with its anti-oxidative activity evidenced by up-regulation of catalase (CAT) and superoxide dismutase (SOD) 1 expression, and reduction of reactive oxygen species (ROS) production. Atractylodin also significantly suppressed expression of transient receptor potential channels 6 (TRPC6) and phosphorylated Ca2+/calmodulin-dependent protein kinase IV (CaMK4) in cultured podocytes with fructose exposure. Additionally, in fructose-exposed podocytes, CaMK4 siRNA up-regulated synaptopodin and reduced podocyte hypermotility, whereas, silencing of TRPC6 by siRNA decreased p-CaMK4 expression, inhibited podocyte hypermotility, showing TRPC6/p-CaMK4 signaling activation in podocyte hypermotility under fructose condition. Just like atractylodin, antioxidant N-acetyl-L-cysteine (NAC) could inhibit TRPC6/p-CaMK4 signaling activation to reduce fructose-induced podocytes hypermotility. These results first demonstrated that the anti-oxidative property of atractylodin may contribute to the suppression of podocyte hypermotility via inhibiting TRPC6/p-CaMK4 signaling and restoring synaptopodin expression abnormality.

Effects of cultural medium on the formation and antitumor activity of polysaccharides by Cordyceps gunnii.

The effects of culture medium composition (i.e., carbon and nitrogen sources) on the growth of mycelia, molecular weight distribution and antitumor activity of intracellular polysaccharides (IPS) from Cordyceps gunnii were investigated. Sucrose and peptone were proved to be the best carbon and nitrogen sources for mycelia growth and remarkably improved IPS production. When the sucrose concentration was 2.0%, the mycelium yield reached up to 15.94±1.26 g/L, but with lower IPS yield; whereas the sucrose concentration was 4.5%, IPS yield reached to a maximum of 138.78±3.89 mg/100 mL. The effects of different carbon/nitrogen (C/N) ratios with equal amounts of carbon source matter on the mycelia and IPS formation were optimized. It found that the yield of mycelia and IPS were both reached to the highest at a C/N ratio of 10:3. In addition, the IPS had the highest macro molecular polysaccharide content and antitumor activity when sucrose concentration was 3.5% and the C/N ratio was 10:1.5. Thus, there was a positive correlation between molecular weight distribution and antitumor activity of IPS by C. gunnii.

Structural properties of polysaccharides from cultivated fruit bodies and mycelium of Cordyceps militaris.

The structural properties of polysaccharides, respectively, obtained from the fermented mycelium and cultivated fruiting bodies of the Cordyceps militaris were investigated and compared in this paper. First, the crude polysaccharides were extracted from the mycelium and the fruiting bodies, respectively. The polysaccharides were successively purified by Sevag and chromatography on Sephadex G-100 column to produce two polysaccharides fractions termed CMPS-II and CBPS-II, respectively. The average molecular weights of CMPS-II and CBPS-II were 1.402×10(3) kDa and 1.273×10(3) kDa, respectively, and they were mainly composed of mannose, glucose and galactose in the mole ratios of 1:28.63:1.41 and 1:12.41:0.74, respectively, for CMPS-II and CBPS-II. Afterward, the structural features of CMPS-II and CBPS-II were investigated by a combination of chemical and instrumental analysis, such as FT-IR, periodate oxidation-Smith degradation, GC-MS, NMR and methylation analysis. The results indicated that structurally, both CMPS-II and CBPS-II were 1,3-branched-galactomannoglucan that had a linear backbone of (1→4)-linked α-D-glucopyranose (Glcp). Congo-red test revealed that CMPS-II and CBPS-II existed as triple-helical chains in 0.05-0.15 M NaOH solution.

Weibull kinetic modeling and nutritional effects of high-hydrostatic-pressure sterilization of soft-packing boiled bamboo shoots.

Application of high-hydrostatic-pressure (HHP) sterilization technology to boiled bamboo shoots was preliminarily discussed. An improved Weibull model that considered pressure and time as independent variables simultaneously for simulating the sterilization result was obtained by fitting the microbial lethal curves with high precision (R 2>0.98). HHP sterilization parameters could be calculated using this model with a certain disinfection rate. For a sterilization rate of 99.5%, treatment with a pressure of 400 MPa for 6 min or 500 MPa for 3 min at room temperature could exterminate all pathogenic microorganisms in boiled bamboo shoots, and control the total number of colonies at a low level below 100 CFU/g. Comparisons of the effects of HHP, high-pressure steam and microwave on the softness and contents of soluble protein and vitamin C of samples were also made. The results showed that the extent of damage of the products' original quality caused by HHP sterilization was less than that caused by the thermal and microwave treatment processes with equivalent sterilization percentages.

The intracellular mechanism of action on Escherichia coli of BF2-A/C, two analogues of the antimicrobial peptide Buforin 2.

In the present study, the antimicrobial peptides BF2-A and BF2-C, two analogues of Buforin 2, were chemically synthesized and the activities were assayed. To elucidate the bactericidal mechanism of BF2-A/C and their different antimicrobial activities, the influence of peptides to E. coli cell membrane and targets of intracellular action were researched. Obviously, BF2-A and BF2-C did not induce the influx of PI into the E. coli cells, indicating nonmemebrane permeabilizing killing action. The FITC-labeled BF2-A/C could penetrate the E. coli cell membrane and BF2-C penetrated the cells more efficiently. Furthermore, BF2-A/C could bind to DNA and RNA respectively, and the affinity of BF2-C to DNA was powerful at least over 4 times than that of BF2-A. The present results implied that BF2-A and BF2-C inhibited the cellular functions by binding to DNA and RNA of cells after penetrating the cell membranes, resulting in the rapid cell death. The structure-activity relationship analysis of BF2-A/C revealed that the cell-penetrating efficiency and the affinity ability to DNA were critical factors for determining the antimicrobial potency of both peptides. The more efficient cell-penetrating and stronger affinity to DNA caused that BF2-C displayed more excellent antimicrobial activity and rapid killing kinetics than BF2-A.

Efficient bioconversion of compactin to pravastatin by the quinoline-degrading microorganism Pseudonocardia carboxydivorans isolated from petroleum-contaminated soil.

Pravastatin is one of the first available statins on the market. The purpose of this study was to isolate and identify the quinoline-degrading microorganism from petroleum-contaminated soil that could bioconvert compactin to pravastatin. There were 10,011 microorganism colonies isolated; five strains showed a higher capability for quinoline biodegradation. These five strains were evaluated for their pravastatin bioconversion ability; Pseudonocardia sp. had the highest efficiency for conversion of compactin to pravastatin. The strain was further identified as Pseudonocardia carboxydivorans PAH4. The bioconversion rates were studied under difference incubation conditions. Pre-incubation in medium containing 0.005% compactin sodium, resulted in the compactin utilization rate of almost 100% in a 1mg/ml compactin-containing medium. The rate of conversion of pravastatin was up to 68% after 6 days of incubation. In conclusion, the results of this study suggest that P. carboxydivorans PAH4 could be considered a candidate for the production of pravastatin on an industrial scale.

Protective effect of green tea (-)-epigallocatechin-3-gallate against the monoamine oxidase B enzyme activity increase in adult rat brains.

OBJECTIVE: Monoamine oxidase B (MAO-B) levels were observed increasing during aging in rat brains. (-)-Epigallocatechin-3-gallate (EGCG) is the major polyphenolic constituent in green tea. The objective of the present study was to investigate the EGCG compound for its effect on preventing an increase in MAO-B activity in rat brains. The total antioxidant capacity and lipid peroxidation of rats were also assessed. METHODS: Rats were assigned to three groups: Control, VE (α-tocopherol), and EGCG. Twenty-four male Long-Evans rats were fed normal diets for a total of 11 wk and test diets for a total of 12 wk. The serum analysis, serum total antioxidant capacity, tissue lipid peroxidation, and monoamine oxidase B enzyme activity were measured. The differences between the groups and between the control and experimental groups were analyzed. The correlation among the experimental results was also analyzed. RESULTS: The serum total antioxidant capacity of the EGCG group was higher than that observed in the Control and VE groups. In rat brains and livers, the lipid peroxidation levels were lower in the VE and EGCG groups compared with Control groups. EGCG and VE groups showed lower MAO-B enzyme activity in rat brains compared with Control groups. In contrast to the brain findings, there were no significant differences in the MAO-B enzyme activity among groups in rat livers. CONCLUSION: The present study first indicates that EGCG supplementation was able to execute a tissue-selective decrease in the brain MAO-B enzyme activity in adult rats, in which it was actualized by way of preventing physiological peroxidation.

Development of real-time and nested RT-PCR to detect astrovirus and one-year survey of astrovirus in Jiangmen City, China.

Human astroviruses (HAstVs) are one of the major viral agents of acute gastroenteritis (AGE) in all age groups, especially in young children. In this study, new one-step real-time RT-PCR and nested RT-PCR assays were developed to detect HAstVs. HAstVs were identified in 46 (8.75%) of 526 stool samples in Jiangmen City over 1 year, including 43 (9.15%) of 470 children and 3 (5.4%) of 56 adults, and HAstV-1 was the most predominant strain. This finding suggests that HAstVs infections are common in Jiangmen City, China. Further detailed molecular epidemiological studies are required for understanding the prevalence of HAstVs infection and gaining knowledge about the circulating genotypes.

Five serum proteins identified using SELDI-TOF-MS as potential biomarkers of gastric cancer.

OBJECTIVE: The aims of this study were to detect serum proteomic patterns in gastric cancer serum samples using Surface-enhanced Laser Desorption/ionization-Time-of-flight-Mass Spectrometry ProteinChip array technology, to screen biomarker candidates, to build diagnostic models and to evaluate their clinical significance. METHODS: Serum samples from patients with gastric cancer and normal healthy control subjects (n = 125) were analysed using surface-enhanced laser desorption/ionization technology. The spectra were generated on weak cation exchange (WCX2) chips, and protein peak clustering and classification analyses were established using Ciphergen Biomarker Wizard and Biomarker Pattern software, respectively. The diagnostic models were developed and validated by discriminant analysis. In addition, the results of the surface-enhanced laser desorption/ionization model were compared with the biomarkers carcinoembryonic antigen and carbohydrate antigen 199 in a subset of samples using a microparticle enzyme immunoassay. RESULTS: Five protein peaks at 2046, 3179, 1817, 1725 and 1929 m/z were automatically chosen as components of the best biomarker pattern for diagnosis of gastric cancer. In addition, we identified a single protein peak at 4665 m/z, which could distinguish between stage I/II and stage III/IV gastric cancer with a specificity and sensitivity of 91.6% (11/12) and 95.4% (21/22), respectively. When this biomarker was validated in the second set of samples, the specificity and sensitivity were 91.7% (11/12) and 86.3% (19/22), respectively. CONCLUSIONS: The present results suggest that serum surface-enhanced laser desorption/ionization protein profiling can distinguish patients with gastric cancer, and in particular stage I/II patients, from normal subjects with a relatively high sensitivity and specificity. Surface-enhanced Laser Desorption/ionization-Time-of-flight-Mass Spectrometry is a potential new diagnostic tool for the screening of gastric cancer.

The membrane action mechanism of analogs of the antimicrobial peptide Buforin 2.

Previously, the antimicrobial peptides BF2-A and BF2-B, two analogs of Buforin 2 that was hypothesized to kill bacteria by entering cells and binding nucleic acids, had been designed based on the structure-activity analysis of Buforin 2. In the present study, BF2-A and BF2-B were chemically synthesized and their activities and lipopolysaccharide affinity were assayed. To elucidate the mechanism of action with cytoplasmic membranes, we subsequently examined the membrane permeability of both peptides in detail. Both peptides showed stronger antimicrobial activities against a broad spectrum of microorganisms than their parent peptide. Interestingly, BF2-A did not cause significant membrane permeabilization for influx of ONPG into cells, and hardly caused the leakage of intracellular macromolecules, probably BF2-A slightly disturbed cell membrane causing the K(+) leakage during peptide crossing phospholipids bilayer. Electron micrographs indicated that the cell membrane treated by BF2-A was still intact within 20min. On the contrary, BF2-B obviously increased the outer and inner membrane permeability, even induced the slight leakage of macromolecules in the cytoplasm. The leakage of cytoplasmic contents was also demonstrated by the electron micrographs. The increase of membrane permeabilization explained why BF2-B displayed better antimicrobial activity and rapid killing kinetics than BF2-A.

Insertion mode of a novel anionic antimicrobial peptide MDpep5 (Val-Glu-Ser-Trp-Val) from Chinese traditional edible larvae of housefly and its effect on surface potential of bacterial membrane.

Antimicrobial molecules from insects may serve as a potentially significant group of antibiotics. To identify the effect of antimicrobial peptides (AMPs) on bacterial membrane and obtain further insight in the mechanism of membrane transport of AMPs, the interaction of surface potential and permeation of a novel antimicrobial peptide MDpep5 (Val-Glu-Ser-Trp-Val) from Chinese traditional edible larvae of housefly was examined using liposomes from bacterial lipids extract. Compared with the cationic AMPs, MDpep5 cannot completely disrupt membrane. The uptake of MDpep5 by bacterial liposomes was dependent on the membrane surface potential. The mutual inhibition of the transport of MDpep5 through the cell membrane was caused by the change in surface potential due to the binding of MDpep5 to the membrane. Furthermore, formation of MDpep5-enriched lipid aggregates could lead to the disorder of the bilayer structure. Based on our experimental data, we propose that MDpep5 initiated its antimicrobial activity by profoundly disordering the structure and affecting physical properties of bacterial membrane when binding to the phospholipid which accounts for its bactericidal activity.

Both inorganic and organic selenium supplements can decrease brain monoamine oxidase B enzyme activity in adult rats.

It has been observed that the levels of brain monoamine oxidase B (MAO-B) increase during ageing. MAO catalyses the oxidative deamination of neurotransmitters, in which the by-product H2O2 is subsequently generated. Se exists naturally in inorganic and organic forms and is considered to play a key role in antioxidation functioning. The objective of the present study was to investigate two chemical forms of Se compounds for their inhibition effect on rat brain MAO-B. The total antioxidant capacity and lipid peroxidation of rats were also examined. The rats (age 7 weeks) were divided into four groups: the control group, tocopherol group (T group, positive control), selenite group (SE group, representing the inorganic Se group) and seleno-yeast group (SY group, representing the organic Se group). The rats were fed for 11 weeks with normal diets and 12 weeks with test diets. The serum total antioxidant capacity of the SE and SY groups was significantly higher than that in the control and T groups. In rat brains and livers, the lipid peroxidation levels were significantly decreased in the T, SE and SY groups. MAO-B activity showed a significant decrease in the T, SE and SY groups in rat brains but no significant change could be noted in the rat livers. In conclusion, the present study indicates that inorganic or organic Se supplementation can decrease the brain MAO-B enzyme activity in adult rats and can be accomplished by the effect of the Se antioxidation capability.

Design and analysis of structure-activity relationship of novel antimicrobial peptides derived from the conserved sequence of cecropin.

We have de novo designed four antimicrobial peptides AMP-A/B/C/D, the 51-residues peptides, which are based on the conserved sequence of cecropin. In the present study, the four peptides were chemically synthesized and their activities assayed. Their secondary structure, amphipathic property, electric field distribution and transmembrane domain were subsequently predicted by bioinformatics tools. Finally, the structure-activity relationship was analyzed from the results of activity experiments and prediction. The results of activity experiments indicated that AMP-B/C/D clearly possessed excellent broad-spectrum activity against bacteria, whereas AMP-A was almost inactive against most of the bacterial strains tested. AMP-B/C/D showed more potent activity against Gram-positive bacteria than against Gram-negative bacteria. By utilizing bioinformatics analysis tools, we found that the secondary structure of the four cation peptides was mainly alpha-helix, and the result of CD spectrum also displayed that all the peptides had considerable alpha-helix in the presence of either 50% TFE or SDS micelles. AMP-C showed much better activity than other peptides against most of the bacteria tested, owing to its remarkable cation property and the amphipathic character of its N-terminal. The study of structure-activity relationship of the designed peptides confirmed that amphipathic structure and high net positive charge were prerequisites for maintaining their activities.

[Molecular epidemiological study of human calicivirus infection in diarrhea children in autumn and winter at a hospital in Guangzhou].

OBJECTIVE: To investigate the epidemiological features of human calicivirus( HuCV) infection in children with diarrhea in a hospital in Guangzhou. METHODS: Stool specimens were collected from children with viral diarrhea diagnosed between October, 2003 and January, 2004 and between October, 2004 and January, 2005. HuCV was detected by means of RT-PCR and sequence analysis of the PCR products. RESULTS: Eighty specimens positive for Norwalk-like viruses (NLVs) were identified from 648 stool specimens, with a positivity rate of 12.35%, and sapporo-like viruses (SLVs) were identified in 2 specimens (0.31%). The monthly NLV positivity rate was 11.74% (Oct.), 14.16% (Nov.), 9. 09% (Dec.) and 13.95% (Jan.), respectively, showing no significant variation in these months. NLVs mainly infected children below 2 years old. Twenty-two strains of NLVs were sequenced and analyzed, and 21 of them were identified as GII and the genotype of 1 strain could not be determined. The prevalent viral population were GII-3 and GII-4 in 2003 and was GII-4 in 2004, and both of the SLVs belong to GI-1. CONCLUSION: NLVs is one of the important pathogens causing sporadic acute gastroenteritis in children admitted in the hospital in Guangzhou, and the prevalent strains are GII-3 and GII-4 , but different prevalent strains are possible in different periods.