Bacterial therapy has attracted increasing attention due to its special mechanism and abundant applications. With the flourishing development of synthetic biology, therapeutic genes have been introduced into engineering bacteria to improve their antitumor efficacy. However, it is difficult to spatiotemporally control the expression of these therapeutic genes at the tumor site in vivo, thereby considerably limiting the application of engineered bacteria in tumor treatment. To resolve this problem, we constructed a temperature-responsive bacterial strain capable of triggering the expression of exogenous genes in a laser-controllable way. Noxa, a pro-apoptotic protein, is chosen to test the expression of exogenous protein and its anti-tumor effect in engineered bacteria upon laser irradiation. Firstly, Noxa was fused to the C-terminus of the bacterial outer membrane protein cytolysin A (ClyA), and then the recombinant gene fragment ClyA-Noxa was inserted into the temperature-sensitive plasmid pBV220 and the recombinant plasmid was transformed into non-pathogenic Escherichia coli MG1655. Thus, we constructed the engineering strain (TRB@Noxa) that could express Noxa on the bacterial surface. TRB@Noxa could target and colonize the tumor tissue without causing notable host toxicity. The bacterial infection triggered thrombosis in the tumor tissue, resulting in the darkness of tumor sites. In a xenograft mouse tumor model, our strategy demonstrated precise tumor targeting and strong tumor inhibition. In conclusion, we successfully constructed a new engineering bacterial strain TRB@Noxa. TRB@Noxa combined with photothermal therapy could arrest tumor growth in the absence of photosensitizers, which represents an appealing method for antitumor therapy in the future.
Escherichia coli/radiation effects* ; Animals ; Humans ; Lasers ; Mice ; Proto-Oncogene Proteins c-bcl-2/biosynthesis* ; Neoplasms/therapy* ; Genetic Engineering ; Cell Line, Tumor ; Escherichia coli Proteins/genetics*

Objective: Owing to antibiotic abuse and the subsequent development of antibiotic resistance, bacterial infection has become one of the most persistent unresolved problems. New antibacterial agents, especially those that are environmental-friendly, are urgently needed. Methods: Melanin extracted by filtration centrifugation and acid and proteolytic hydrolysis was characterized using UV, FTIR, TEM, and XPS. Photothermal conversion was calculated, and the bacteriostatic effects, and , were assessed by plate counting and ratios (%) of wound areas. Results: Natural melanin hydrolyzed by trypsin had good photothermal conversion effects, which resulted in superior bacteriostatic activities. The extracted melanin along with laser NIR irradiation at 808 nm promoted the healing of wounds infected by drug-resistant bacteria and was biocompatible according to toxicity tests and . Conclusion The present findings indicated a safe and efficient method of developing natural antibacterial agents.
Animal Shells ; chemistry ; Animals ; Anti-Bacterial Agents ; pharmacology ; Escherichia coli ; drug effects ; radiation effects ; Escherichia coli Infections ; drug therapy ; Melanins ; pharmacology ; Mytilus edulis ; chemistry ; Photochemical Processes ; Rats ; Rats, Sprague-Dawley ; Staphylococcal Infections ; drug therapy ; Staphylococcus aureus ; drug effects ; radiation effects ; Wound Healing

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

OBJECTIVEThe growth and repair potential of three typical microorganisms in reclaimed water after UV disinfection was investigated to assess the effects of photo-reactivation and dark repair of microorganisms, and the microbial safety of reclaimed water following this procedure.

METHODSThe growth and repair potential of Escherichia coli, a fecal coliform strain and Bacillus subtilis in the effluent of a biological wastewater treatment plant disinfected by a low-pressure UV lamp were investigated.

RESULTSAny increase in bacterial numbers in the effluent after UV disinfection was due to damage repair. Exposure to photo-reactivating light for 8-10 h after UV irradiation with a dose of 5 mJ/cm(2), the highest percentage of photo-reactivation observed for E. coli and the fecal coliform strain was 29% and 15% respectively. B. subtilis showed little photo-reactivation under these conditions. The percentage of photo-reactivation was related to the UV dose and the photo-reactivating time, and a function was developed to forecast the final concentrations of E. coli and the fecal coliform strain after UV disinfection with possible photo-reactivation.

CONCLUSIONDifferent species of bacteria displayed different responses to UV light and different repair potentials. The repair of indigenous bacteria in wastewater needs to be investigated in future work.

Bacillus subtilis ; radiation effects ; Dose-Response Relationship, Radiation ; Escherichia coli ; radiation effects ; Time Factors ; Ultraviolet Rays ; Waste Disposal, Fluid ; Water Microbiology ; Water Purification

This paper is aimed to provide the methods of quality control and bioassay of traditional Chinese medicine injections including bioassay method. Shuanghuanglian freeze-dried powder for injection (SFPI) was chosen as study object. HPLC-ELSD fingerprints of SFPI had been established and the samples were differentiated by similarity calculation. Meanwhile, biological profiles of SFPI on Escherichia coli had been established by microcalorimetry. The similarity values were calculated using the correlation coefficient, based on quantitative thermo-kinetic parameters (T2m, Tj, I%). The results indicated that HPLC-ELSD fingerprints, which showed content changes of chemical components, could not monitor minimal variation of different samples, especially that of biological pollutants, while biological profiles could sensitively detect antibiotic activity alterations of the samples, which were kept under specific conditions. In conclusion, characterized by two-dimension, microcalorimetry could supply thermograms as biological profiles characterized to describe the bioactivity of drugs. This study could clearly demonstrate that the correlative detection was proposed as an efficient strategy for quality control of SFPI, based on HPLC-ELSD fingerprints and biological profiles, which could detect quality fluctuation of samples early and quickly and predict the potential adverse drug events (ADE) for ensuring clinical safety.
Calorimetry ; Chromatography, High Pressure Liquid ; methods ; Drug Combinations ; Drugs, Chinese Herbal ; administration & dosage ; chemistry ; pharmacology ; Escherichia coli ; drug effects ; Freeze Drying ; Injections ; Light ; Powders ; Quality Control ; Quantitative Structure-Activity Relationship ; Scattering, Radiation

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

Genomic DNA sequence analysis of phytochrome like photoreceptors in a number of bacteria revealed several open reading frames (ORFs) encoding proteins with amino acid sequences homologous to plant phytochromes. The phytochrome like photoreceptors, collectively called bacteriophytochromes, contain an N-terminal domain homologous to the chromophore-binding domain (CBD) of higher plants and a C-terminal domain of histidine kinase domain( HKD). Due to their simple structure, bacteriophytochromes broaden the view of phytochrome evolution and provide us with a simple model to investigate phytochrome-mediated light signal in higher plants. In this report, the bacteriophytochromes from Synechocystis sp. PCC6803 were investigated. The gene cph1 and its fragment cph1 (C-435) were isolated from the Synechocystis sp. PCC6803 genomic DNA by polymerase chain reaction(PCR) using specific primers. Then, the genes were cloned with the vector pBluescript, yielding plasmids pBlu-cphl and pBlu-cph1 ( C-435), before they are subcloned with the vector pET30, using the EcoRV and Xho I restriction sites. pBlu-cph1, pBlu-cph1 (N-435) were cleaved with Sma I and Xho I, and the released genes were ligated to the pET30a fragment. The E. coli [strain BL21 (DE3)] cells containing recombinant pET30a were grown in medium RB at 20 degrees C, and harvested 6 h later after induction with isopropyl thio-beta-D-galactoside (IPTG). Then, reconstitution systems were employed to study the characteristics of the genes. In the reconstitution system, autoassembly of aprotein of phytochrome with PCB was investigated. The chromophore addition was an autocatalytic process. Reconstitution products were red/infrared (R/FR) photochromic, which was similar to that of the phytoehrome in higher plants. How ever, the spectral change ratios (deltaAmax/deltaAmin) of the two fragments differed from each other. It was also shown that PCB was covalently bound to apo-protein via Zn2+ fluoresc ence SDS-PAGE. After irradiation by light of 700 nm, the maximum absorption spectrum o f holo-Cphl was 650nm. The absorption of it after denaturatior in the dark with ur ea in the presence of hydrochloric acid (pH = 2) was 660nm, which was similar with th at of cis-PCB. In addition, after irradiation by light of 650nm, the maximum absorption spectrum of holo-Cph1 was 700nm. The absorption of it after denaturation in the dark with urea in the presence of hydrochloric acid (pH = 2) was 600nm, which was similar with that of trans-PCB. The result showed that the photochromism of phytochrome resulted from the isomerizaation of chromophore (PCB in this report). The reconstitution of Cph1 (C-435) under the same condition supported the conclusion. Fluorescence emission spectrum of the products suggested that bacteriophytochrom e structure with cis-PCB was more stable than that with trans-PCB. The new reconstitution system in this report sets a base for the application of phytochrome as photochromic biomaterials in biosensors. In addition, phytochrome shows great potential in food, cosmetic and biological engineering, etc.
Bacterial Proteins ; biosynthesis ; chemistry ; genetics ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Gene Expression Regulation, Bacterial ; radiation effects ; Genetic Vectors ; Photochemistry ; Phytochrome ; biosynthesis ; chemistry ; genetics ; Protein Kinases ; biosynthesis ; chemistry ; genetics ; Recombinant Proteins ; biosynthesis ; chemistry ; genetics ; Synechocystis ; chemistry