To explore the effects of intrauterine infection on early growth and neurobehavioral development in neonatal rats. (E. coli) was inoculated into uterine cervix of pregnant rats with gestation of 15 d to establish the intrauterine infection model, and the effect on the delivery of pregnant rats was observed. The neonatal rat brain tissue was stained with Hematoxylin-Eosin and the cerebral white matter damage was assessed. Immunohistochemical staining and Western blot analysis were performed to evaluate the expression of glial fibrillary acidic protein (GFAP), 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and neurofilament (NF) in pup brains. Birth weight and early growth development indices were monitored,and neurobehavioral tests were performed to access the change of neurobehavioral development in neonatal rats. The white blood cell count increased significantly in the uterus and placenta of the pregnant rats after intrauterine E. coli infection and no significant impact was observed on the delivery of pregnant rats. Weak staining and focal rarefaction of cerebral white matter from rats at P7 in intrauterine infection group were observed. The expression of GFAP markedly increased (<0.05) in infection group, while the level of CNPase and NF in pup brains at P7 significantly decreased (<0.05 or <0.01). Compared with control group, the neonatal rats in infection group had lower birth weight and slower weight gain during the suckling period (<0.05 or <0.01), and the completion times of ear opening, eye opening, surface righting, negative geotaxis, acoustic startle and swimming test in infection group were significantly delayed (<0.05 or <0.01). Intrauterine infection in pregnant rats can induce cerebral white matter damage and retardation of early growth and neurobehavioral development in neonatal rats.
Animals ; Animals, Newborn ; Behavior, Animal ; Body Weight ; Disease Models, Animal ; Escherichia coli ; Escherichia coli Infections ; complications ; physiopathology ; Female ; Glial Fibrillary Acidic Protein ; genetics ; Growth Disorders ; etiology ; Leukoencephalopathies ; etiology ; Pregnancy ; Pregnancy Complications, Infectious ; physiopathology ; Rats ; Rats, Sprague-Dawley

Isolated alkaloids from Coptis chinensis Franch. The compounds were identified as berberine, columbamine, groenlandicine, jatrorrhizine, magnoflorine, corydaldine and ferulic acid methylester. Then measured their bitter degree based on the electronic tongue and evaluated the antibacterial. The results based on the Electronic Tongue showed that berberine, columbamine, groenlandicine and jatrorrhizine have higher bitter degree than magnoflorine and corydaldine. And they also appeared better antibacterial activity on E. coli and S. aureus. The correlation coefficients between bitter degree and the two bacteria antibacterial activity were 0.983 and 0.911. So there was close relationship between the bitter degree and antibacterial activity of bitter components. Thus, it is confirmed further that bitter components are the material foundation of medicinal effectiveness of bitter herbs.
Aporphines ; analysis ; Berberine ; analogs & derivatives ; analysis ; Berberine Alkaloids ; analysis ; Biomedical Research ; instrumentation ; methods ; Coptis ; chemistry ; Drugs, Chinese Herbal ; analysis ; chemistry ; pharmacology ; Electronics ; instrumentation ; methods ; Escherichia coli ; drug effects ; growth & development ; Microbial Sensitivity Tests ; Reproducibility of Results ; Staphylococcus aureus ; drug effects ; growth & development ; Taste

Electrical potentials up to 800 mV can be observed between different metallic dental restorations. These potentials produce fields in the mouth that may interfere with microbial communities. The present study focuses on the impact of different electric field strengths (EFS) on the growth of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) in vitro. Cultures of S. aureus and E. coli in fluid and gel medium were exposed to different EFS. Effects were determined by calculation of viable counts and measurement of inhibition zones. In gel medium, anodic inhibition zones for S. aureus were larger than those for E. coli at all field strength levels. In fluid medium, the maximum decrease in the viable count of S. aureus cells was at 10 V⋅m(-1). Field-treated S. aureus cells presented ruptured cell walls and disintegrated cytoplasm. Conclusively, S. aureus is more sensitive to increasing electric field strength than E. coli.
Bacterial Load ; radiation effects ; Bacteriological Techniques ; Caseins ; Cell Wall ; radiation effects ; Culture Media ; Cytoplasm ; radiation effects ; Electricity ; Escherichia coli ; growth & development ; radiation effects ; Gels ; Humans ; Microbial Viability ; radiation effects ; Microscopy, Electron, Transmission ; Protein Hydrolysates ; Sodium Chloride ; Staphylococcus aureus ; growth & development ; radiation effects ; Water

Photosynthetic CO(2) fixation is the ultimate source of organic carbon on earth and thus is essential for crop production and carbon sequestration. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the first step of photosynthetic CO(2) fixation. However, the extreme low carboxylation efficiency of Rubisco makes it the most attractive target for improving photosynthetic efficiency. Extensive studies have focused on re-engineering a more efficient enzyme, but the effort has been impeded by the limited understanding of its structure-function relationships and the lack of an efficient selection system towards its activity. To address the unsuccessful molecular engineering of Rubisco, we developed an Escherichia coli-based activity-directed selection system which links the growth of host cell solely to the Rubisco activity therein. A Synechococcus sp. PCC7002 Rubisco mutant with E49V and D82G substitutions in the small subunit was selected from a total of 15,000 mutants by one round of evolution. This mutant showed an 85% increase in specific carboxylation activity and a 45% improvement in catalytic efficiency towards CO(2). The small-subunit E49V mutation was speculated to influence holoenzyme catalysis through interaction with the large-subunit Q225. This interaction is conserved among various Rubisco from higher plants and Chlamydomonas reinhardtii. Knowledge of these might provide clues for engineering Rubisco from higher plants, with the potential of increasing the crop yield.
Amino Acid Substitution ; Bacterial Proteins ; chemistry ; genetics ; Carbon Dioxide ; chemistry ; Directed Molecular Evolution ; Escherichia coli ; growth & development ; Ribulose-Bisphosphate Carboxylase ; chemistry ; genetics ; Synechococcus ; enzymology

Crystallography, X-Ray ; Escherichia coli ; metabolism ; Fibroblast Growth Factors ; chemistry ; genetics ; metabolism ; Heparin ; metabolism ; Humans ; Models, Molecular ; Protein Binding ; Protein Isoforms ; chemistry ; metabolism ; Protein Structure, Tertiary ; Recombinant Proteins ; biosynthesis ; chemistry ; genetics ; Sulfates ; chemistry ; metabolism

The study is aimed to investigate the effect of lamivudine on growth and metabolism of three intestinal characteristic bacteria (namely, Bifidobacterium adolescentis, Escherichia coli and Shigella dysenteriae). The growth condition of the three bacteria was quantitatively evaluated by microcalorimetry with four characteristic parameters of the thermal power-time curves, including the growth rate constant (k), thermal power (p), time to peak (t) and calorific value (Q). The results showed that the IC50 value of lamivudine on B. adolescentis was 200 microg x mL(-1), and the IC50 values of lamivudine on S. dysenteriae and E. coli were higher than 3 000 microg x mL(-1) and 6 000 microg x mL(1), respectively. Therefore, lamivudine made different inhibitory effects on the three bacteria, in which the B. adolescentis was most susceptible to lamivudine. This work showed that taking lamivudine chronically is likely to affect the balance of good flora in the intestinal tract, and might increase endotoxin release, leading to inflammation and disease progression in hepatopathy.
Anti-Bacterial Agents ; pharmacology ; Bifidobacterium ; growth & development ; Calorimetry ; Escherichia coli ; growth & development ; Lamivudine ; pharmacology ; Shigella dysenteriae ; growth & development

BACKGROUND: Delayed entry of blood culture bottles is inevitable when microbiological laboratories do not operate for 24 hr. There are few studies reported for prestorage of these bottles. The growth dynamics of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were investigated with respect to various preincubation conditions. METHODS: Fifteen or 150 colony-forming units (CFU) of bacteria were inoculated into standard aerobic or anaerobic blood culture bottles. Bottles were preincubated at 25degrees C or 37degrees C for 0, 2, 4, 8, 12, 24, or 48 hr. The time to detection (TTD) then was monitored using the BacT/Alert 3D system (bioMerieux Inc., USA). RESULTS: Significant difference in TTD was observed following preincubation for 8 hr at 25degrees C vs. 4 hr at 37degrees C for S. aureus, 4 hr at 25degrees C vs. 4 hr at 37degrees C for E. coli, 12 hr at 25degrees C vs. 4 hr at 37degrees C for P. aeruginosa, compared to no preincubation (P<0.005). TTD values did not vary significantly with bacterial CFU or with aerobic or anaerobic bottle type. The BacT/Alert 3D system returned false negatives following preincubation of P. aeruginosa for 48 hr at 25degrees C or 24 hr at 37degrees C. CONCLUSIONS: TTD was mainly affected by preincubation temperature and duration rather than by input CFU quantity or bottle type for the 3 experimental bacteria.
Bacteriological Techniques/instrumentation/*methods ; Culture Media ; Escherichia coli/growth & development/*isolation & purification ; Pseudomonas aeruginosa/growth & development/*isolation & purification ; Staphylococcus aureus/growth & development/*isolation & purification ; Temperature ; Time Factors

To produce recombinant phospholipase A(1) (PLA(1)) by Escherichian coli, the pla gene encoding PLA(1) was amplified from Serratia liquefaciens by PCR and cloned into two vectors pET20-b(+) and pET28-a(+). The two recombinant plasmids were then transformed into E. coli BL21 (DE3) individually to express PLA(1). E. coli BL21(DE3)/pET28a-pla yielded extracellular PLA(1) with an activity of 40.8 U/mL in batch cultivations of shaken flasks by auto-induction, which was accounted for 91% of total enzyme activity. On the basis of primal auto-induction medium, the optimized fermentation medium of PLA(1) contained tryptone 10 g/L, yeast extract 5 g/L, glucose 0.8 g/L, lactose 5 g/L, Na2HPO4 25 mmol/L, KH2PO4 25 mmol/L and 1 mmol/L MgSO4 (final concentration). Glycine (7.5 g/L) was added 6 h after inoculated. After incubated at 37 degrees C for 24 h, extracellular enzyme activity reached 128.7 U/mL.
Cloning, Molecular ; Culture Media ; Escherichia coli ; genetics ; growth & development ; metabolism ; Fermentation ; Lactose ; pharmacology ; Phospholipases A1 ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Serratia liquefaciens ; enzymology

Constructing robust gene circuits is a fundamental work for synthetic biology. Bacteria with suicide gene circuit based on quorum-sensing will kill themselves in a controllable pattern upon certain cell density. In the media of different IPTG inducer concentration, we observed the growth and suicidal behavior of the Escherichia coli. Top10F' with such gene circuit, screened the mutants and determined their mutated loci. The results show that, with higher IPTG concentration, the more wild type bacteria were killed; as well the mutants emerged earlier and spread over the population more quickly. The sequence of plasmids in those mutants revealed that a transposon inserted into the luxR gene and therefore disrupted Quorum-Sensing of these individuals. Furthermore, the insertion sequence of the plasmid can solely result in the mutants escaping from suicide.
Culture Media ; chemistry ; DNA Transposable Elements ; genetics ; Escherichia coli ; genetics ; growth & development ; Gene Expression Regulation, Bacterial ; Genes, Synthetic ; genetics ; Genes, Transgenic, Suicide ; Isopropyl Thiogalactoside ; chemistry ; Mutation ; Quorum Sensing ; genetics ; Repressor Proteins ; genetics ; Trans-Activators ; genetics

OBJECTIVETo obtain 1-4 IgG-like domains of mouse vascular endothelial growth factor receptor 2 (VEGFR2) fusion protein (mVEGFR2D1-4/GST) and identify its antiginicity and biological activity.

METHODSThe gene of mVEGFR2D1-4 was amplified by RT-PCR from 14-days embryos of Balb/c mice. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-mVEGFR2D1-4, which was transformed into E. coli BL21 (DE3) strain for mVEGFR2D1-4/GST expression. The fusion protein was identified by SDS-PAGE and Western blotting, and the antigenicity of the protein purified by affinity chromatography was characterized by ELISA. The VEGF blocking effect of the purified protein in human umbilical vein endothelial cells (HUVECs) were evaluated in in vitro cell cultures.

RESULTSThe mVEGFR2D1-4 gene was obtained, which had an identical sequence to that retrieved in GenBank. The prokaryotic expression vector for mVEGFR2D1-4 was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated the antigenicity of the purified mVEGFR2D1-4 fusion protein, which obviously blocked the effect of VEGF in promoting HUVEC proliferation in vitro.

CONCLUSIONThe mVEGFR2D1-4/GST fusion protein obtained shows a strong antigenicity and biological activity to facilitate further study of active anti-tumor immunotherapy targeting VEGFR2.

Animals ; Cell Proliferation ; Escherichia coli ; genetics ; metabolism ; Female ; Gene Expression ; Genetic Vectors ; Human Umbilical Vein Endothelial Cells ; Humans ; Mice ; Mice, Inbred BALB C ; Plasmids ; Recombinant Fusion Proteins ; genetics ; immunology ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; immunology ; isolation & purification