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

This study is to investigate the effect of Cordyceps sinensis and its cultured mycelia on growth and metabolism of Escherichia coli, and microcalorimetric method was carried out to evaluate its biological activity. The study will provide the basis for the quality control of Cordyceps sinensis. Experimental result will show the effect of natural Cordyceps sinensis and its cultured mycelia on growth and metabolism of Escherichia coli, with index of P(1max) and effective rate (E) by microcalorimetry, the data of experiment were studied by cluster analysis. The results showed that Cordyceps sinensis and its cultured mycelia not only can promote growth and metabolism of Escherichia coli but also can regulate the balance of intestinal microecology efficiently. When the concentrations of samples > 6.0 mg mL(-1), natural Cordyceps sinensis can promote the growth and metabolism of Escherichia coli efficiently (P < 0.05) compared with the control group, and have better dose-effect relationship with concentration (r > 0.9), its cultured mycelia does not show conspicuous auxoaction (P > 0.05) and have not dose-effect relationship with concentration (r < 0.6); when the concentration of samples < 6.0 mg mL(-1), all samples does not show conspicuous auxoaction (P > 0.05). Natural Cordyceps sinensis and its cultured mycelia can be distinguished by cluster analysis. Microcalorimetry has a good prospect on the quality evaluation of the traditional Chinese medicine.
Biological Products ; pharmacology ; Calorimetry ; methods ; Cordyceps ; Escherichia coli ; drug effects ; growth & development ; Microchemistry ; methods ; Mycelium

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

Nutrient agar medium was exposed in 0.085-0.092 T static magnetic fields for 12 h. Then we densities the optical densities at lamda = 600 (OD600) of Escherichia coli, Staphylococcus aureus and Bacillus subtilis in different culturing stage. The results were compared with those of control group in the normal geomagnetic field. The OD600 values of experimental groups of these three kinds of aerobes were significantly higher than those of control groups from 3h to 9h. However, after 11 h, there was no remarkable difference regarding the OD600 values between the two groups. The dissolved oxygen content of nutrient agar medium was determined by microtitration. The dissolved oxygen of nutrient agar medium under static magnetic for 12h increased 15% in average and there was significant difference when compared with the control. The results showed that the ferro-magnetic fields increased the dissolved oxygen content of nutrient agar medium significantly. These findings suggest that the effects of static magnetic fields on Escherichia coli, Staphylococcus aureus and Bacillus subtilis are related to the dissolved oxygen.
Bacillus subtilis ; growth & development ; radiation effects ; Culture Media ; radiation effects ; Escherichia coli ; growth & development ; radiation effects ; Magnetic Fields ; Staphylococcus aureus ; growth & development ; radiation effects

A DNA fragment encoding extracellular domain of mouse epidermal growth factor receptor (EGFR) was obtained by PCR from a previous recombinant plasmid. The DNA fragment was then ligated into prokaryotic expression vector, and expressed in Escherichia Coli. The recombinant protein was purified under denature conditions by affinity chromatography, and refolded with gradient dialysis. The recombinant protein could produce antibodies to recognize extracellular domain and full-length of mouse EGFR, and form homodimer in the presence of EGF detected by western blot analysis. These findings provide evidence that the renatured recombinant extracellular domain of mouse epidermal growth factor receptor is immunogenetic and may be important for further application of this protein in functional and immunological research.
Animals ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; Mice ; Plasmids ; Receptor, Epidermal Growth Factor ; biosynthesis ; chemistry ; genetics ; isolation & purification ; Transfection

The fermentation process of recombinant human Endostatin expression in Escherichia coli BL21 (DE3) was studied. The effects of factors such as concentration of IPTG, induction time, cultivation temperature and feeding strategies were investigated. Beside that, by changing the temperature to 40 degrees C after induction, the high-density cultivation finished in a much shorter period. After 9 hours cultivation, the optical density (OD) at 600 nm reached 140 and the yield of inclusion body was 3 g/L. While E. coli system was used, protein with better activity and stability was obtained. The cost was much lower and the producing process was much steadier. It will meet the demands of the industrial production.
Endostatins ; biosynthesis ; genetics ; Escherichia coli ; genetics ; growth & development ; metabolism ; Fermentation ; Humans ; Protein Engineering ; Recombinant Proteins ; biosynthesis ; genetics ; Thiogalactosides ; chemistry

Recently, an increase in incidences of urinary tract infections in uncircumcised male infants has been reported. However, determining what is the best management for the prepuce of newborns and infants is still to be solved. I investigated prospectively how much foreskins are retracted with age and what correlations it has with urinary tract infection in 122 males children below 15 years of age. Under 6 months of age, the majority of the foreskins were unretractable. As they got older, over 3 years of age, their prepuces became retractable. The incidence of bacteriuria was 11.4% in uncircumcised but none in circumcised and hypospadias. In 8 patients showing bacteriuria, their foreskins were retracted below 25% in length. Among them, 5 patients, in whom E. coli were grown in their urine, showed radiologic renal abnormalities and suffered from high fever indicating systemic infection. However, the other 3 cases infected by Proteus mirabilis in their urine complained of only local penile symptoms.
Adolescent ; Bacteriuria/*microbiology ; Child ; Child, Preschool ; Escherichia coli/isolation & purification ; Escherichia coli Infections/*microbiology ; Human ; Infant ; Male ; Penis/*growth & development/*microbiology ; Prospective Studies ; Proteus Infections/*microbiology ; Proteus mirabilis/isolation & purification ; Urinary Tract Infections/microbiology

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

Bispecific antibodies have been exploited as both cancer immunodiagnostics and cancer therapeutics, which have shown promises in clinical trials in cancer imaging and therapy. To improve the anti-tumor effect, an scDb (bispecific single-chain diabody) was constructed from the variable domain genes of two scFvs (single-chain variable fragment antibodies) directed against human EGFR (epidermal growth factor receptor) and VEGFR2 (vascular endothelial growth factor receptor 2) extracellular domains. The anti-EGFR/ anti-KDR scDb was constructed into pHEN2 plasmid and expressed in Escherichia coli HB2151 host. After purification by one-step affinity chromatography of IMAC, scDb protein was characterized by Western blotting. The yield of scDb protein was 570 microg per liter medium. scDb bound to EGFR as efficiently as the parental antibody scFv-E10, while a little bit weaker than the parental antibody scFv-AK404R when bound to KDR. In conclusion, the scDb protein could bind both EGFR and KDR specifically and could be applied for further anti-tumor research.
Antibodies, Bispecific ; biosynthesis ; genetics ; Escherichia coli ; metabolism ; Humans ; Plasmids ; Protein Binding ; Receptor, Epidermal Growth Factor ; immunology ; Single-Chain Antibodies ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor Receptor-2 ; immunology

The existence of symbiotic relationships between Acanthamoeba and a variety of bacteria is well-documented. However, the ability of Acanthamoeba interacting with host bacterial pathogens has gained particular attention. Here, to understand the interactions of Escherichia coli K1 and E. coli K5 strains with Acanthamoeba castellanii trophozoites and cysts, association assay, invasion assay, survival assay, and the measurement of bacterial numbers from cysts were performed, and nonpathogenic E. coli K12 was also applied. The association ratio of E. coli K1 with A. castellanii was 4.3 cfu per amoeba for 1 hr but E. coli K5 with A. castellanii was 1 cfu per amoeba for 1 hr. By invasion and survival assays, E. coli K5 was recovered less than E. coli K1 but still alive inside A. castellanii. E. coli K1 and K5 survived and multiplied intracellularly in A. castellanii. The survival assay was performed under a favourable condition for 22 hr and 43 hr with the encystment of A. castellanii. Under the favourable condition for the transformation of trophozoites into cysts, E. coli K5 multiplied significantly. Moreover, the pathogenic potential of E. coli K1 from A. castellanii cysts exhibited no changes as compared with E. coli K1 from A. castellanii trophozoites. E. coli K5 was multiplied in A. castellanii trophozoites and survived in A. castellanii cysts. Therefore, this study suggests that E. coli K5 can use A. castellanii as a reservoir host or a vector for the bacterial transmission.
Acanthamoeba castellanii/*microbiology ; Animals ; Disease Reservoirs/*microbiology ; Disease Vectors ; Escherichia coli/growth & development/pathogenicity/*physiology ; Oocysts/microbiology ; Symbiosis/*physiology ; Trophozoites/microbiology