ABSTRACT
The targeting of anti-tumor drugs is an important means of tumor treatment and reducing drug side effects. Oxygen-depleted hypoxic regions in the tumour, which oxygen consumption by rapidly proliferative tumour cells, are generally resistant to therapies. Magnetotactic bacteria (MTB) are disparate array of microorganism united by the ability to biomineralize membrane-encased, single-magnetic-domain magnetic crystals (magnetosomes) of minerals magnetite or greigite. MTB by means of flagella, migrate along geomagnetic field lines and towards low oxygen concentrations. MTB have advantage of non-cytotoxicity and excellent biocompatibility, moreover magnetosomes (BMs) is more powerful than artificial magnetic nanoparticles(MNPs). This review has generally described the biological and physical properties of MTB and magnetosomes, More work deals with MTB which can be used to transport drug into tumor based on aerotactic sensing system as well as the competition of iron which is a key factor to proliferation of tumor. In addition, we summarized the research of magnetosomes, which be used as natural nanocarriers for chemotherapeutics, antibodies, vaccine DNA. Finally, We analyzed the problems faced in the tumor treatment using of MTB and bacterial magnetosomes and prospect development trends of this kind of therapy.
Subject(s)
Bacteria , Ferrosoferric Oxide , Gram-Negative Bacteria , Magnetics , Magnetosomes , Neoplasms/therapyABSTRACT
Objective To verify the feasibility and safety of stomach tumor marker localization based on magnetic tracer technique in dogs.Methods Six male Beagle dogs were examined by gastroscopy.Then tracer magnets were sent to the "tumor" locations assumed in advance and fixed near the "tumors" by endoscopic soft tissue clamp.Laparoscopic gastric tumor localization was performed under general anesthesia 24 hours later.The tracer magnet was placed near the tumor on the surface of the stomach through the operating hole after the conventional establishment of laparoscope puncture parallel mirror to explore the tracer magnet.After the two magnets were attracted,the location of the tracer magnet seen under the laparoscope was the location of the gastric tumor,so as to complete the labeling and positioning of the lesion.Results All the 6 Beagle dogs were successfully implanted with tracer magnets under gastroscopy.Twenty-four hours after the gastroscopy,the pursuit magnet was successfully implanted during laparoscopic surgery.The two magnets automatically attracted each other and formed a sandwich structure of "tracer magnet-gastric wall-pursuit magnet ",which completed the location and identification of gastric tumor under the laparoscopy.Conclusion Gastroscopy combined with laparoscopy based on magnetic tracer technique is simple,accurate,safe and feasible.
ABSTRACT
ABSTRACT Magnetotactic bacteria are mostly microaerophilic found at the interface between oxic-anoxic zones. We report a magnetotactic bacterial strain isolated from an oil refinery sludge sample that grows aerobically in simple chemical growth medium, 9K. They open a new window of isolation of magnetic nanoparticles through an easy natural living system.
ABSTRACT
BACKGROUND:In an additional changing magnetic field, magnetosomes can invade the tumor cells and inhibit their proliferation.OBJECTIVE: To study the effect of targeted delivery of pHSP70-shPLK1/DOX compounds with magnetosome of magnetotactic bacteria on the treatment of osteosarcoma.METHODS: Human osteosarcoma cell U2OS was divided into four groups: group A: magnetosomes of magnetotactic bacteria+pHSP70-shPLK1/DOX complex; group B: magnetosomes of magnetotactic bacteria; group C: magnetosomes of magnetotactic bacteria+pHSP70-shPLK1/DOX complex, combined with magnetic intervention; group D: magnetosomes of magnetotactic bacteria, combined with magnetic intervention. After 12, 24, 48 and 72 hours of culture, the uptake rate of osteosarcoma cells was observed; cell cycle was evaluated by flow cytometry; PLK1 mRNA and protein expression levels were detected by RT-PCR and western blot, respectively; cell proliferation was explored by MTT assay; cell adhesion and invasion were checked by adhesion assay and Transwel chamber assay, respectively; and the apoptosis rate was measured by apoptosis detection Kit.RESULTS AND CONCLUSION: (1) After culture of 12 and 24 hours, the uptake rate was the highest in group D; meanwhile, the uptake rate was the highest in group B after 48 and 72 hours of culture. (2) The ratio of G2/M phase decreased and the ratio of G0/G1 increased gradualy in group A, group C and group D; the G2/M phase ratio of C group was the lowest at each time point, followed by group D, and that of group A was the highest; and the G2/M phase ratio increased gradualy in group B. (3) Folowing 12 and 24 hours of culture, the expression of PLK1 in group B and group D was higher than that in group A and group C (P < 0.05); in addition, the expression of PLK1 in group B was higher than that in the other three groups after 48 and 72 hours of culture (P < 0.05), and the PLK1 level in group D was higher than that in group A and group C (P < 0.05). (4) The proliferation, adhesion and invasion ability in group B were the highest at different time points, but the apoptosis rate was the lowest. Furthermore, the proliferation, adhesion and invasion abilities in group C were the lowest at different time points, and the apoptosis rate was the highest. To conclude, our experimental results show that the targeted delivery of pHSP70-shPLK1/DOX complex by magnetosomes of magnetotactic bacteria can enhance the apoptosis of osteosarcoma cells and inhibit their proliferation and invasion.
ABSTRACT
The culture of Magnetospirillum magneticum WM-1 depends on several control factors that have great effect on the magnetic cells concentration. Investigation into the optimal culture conditions needs a large number of experiments. So it is desirable to minimize the number of experiments and maximize the information gained from them. The orthogonal design of experiments and mathematical statistical method are considered as effective methods to optimize the culture condition of magnetotactic bacteria WM-1 for high magnetic cells concentration. The effects of the four factors, such as pH value of medium, oxygen concentration of gas phase in the serum bottle, C:C (mtartaric acid: msuccinic acid) ratio and NaNO3 concentration, are simultaneously investigated by only sixteen experiments through the orthogonal design L16(44) method. The optimal culture condition is obtained. At the optimal culture condition (pH 7.0, a oxygen concentration 4.0%, C: C (mtartaric acid: msuccinic acid) ratio 1:2 and NaNO3 100 mg l-1), the magnetic cells concentration is promoted to 6.5×107 cells ml-1, approximately 8.3% higher than that under the initial conditions. The pH value of medium is very important factor for magnetic cells concentration. It can be proved that the orthogonal design of experiment is of 90% confidence. The results from the hysteresis of WM-1 shows that Hc = 230 Oe, Ms = 0.9 emu/g dry wt. Cells,and Mr / Ms = 0.50.
ABSTRACT
The culture of Magnetospirillum magneticum WM-1 depends on several control factors that have great effect on the magnetic cells concentration. Investigation into the optimal culture conditions needs a large number of experiments. So it is desirable to minimize the number of experiments and maximize the information gained from them. The orthogonal design of experiments and mathematical statistical method are considered as effective methods to optimize the culture condition of magnetotactic bacteria WM-1 for high magnetic cells concentration. The effects of the four factors, such as pH value of medium, oxygen concentration of gas phase in the serum bottle, C:C (mtartaric acid: msuccinic acid) ratio and NaNO3 concentration, are simultaneously investigated by only sixteen experiments through the orthogonal design L16(44) method. The optimal culture condition is obtained. At the optimal culture condition (pH 7.0, a oxygen concentration 4.0%, C: C (mtartaric acid: msuccinic acid) ratio 1:2 and NaNO3 100 mg l-1), the magnetic cells concentration is promoted to 6.5×107 cells ml-1, approximately 8.3% higher than that under the initial conditions. The pH value of medium is very important factor for magnetic cells concentration. It can be proved that the orthogonal design of experiment is of 90% confidence. The results from the hysteresis of WM-1 shows that Hc = 230 Oe, Ms = 0.9 emu/g dry wt. Cells,and Mr / Ms = 0.50.
ABSTRACT
The culture of Magnetospirillum magneticum WM-1 depends on several control factors that have great effect on the magnetic cells concentration. Investigation into the optimal culture conditions needs a large number of experiments. So it is desirable to minimize the number of experiments and maximize the information gained from them. The orthogonal design of experiments and mathematical statistical method are considered as effective methods to optimize the culture condition of magnetotactic bacteria WM-1 for high magnetic cells concentration. The effects of the four factors, such as pH value of medium, oxygen concentration of gas phase in the serum bottle, C:C (mtartaric acid: msuccinic acid) ratio and NaNO3 concentration, are simultaneously investigated by only sixteen experiments through the orthogonal design L16(44) method. The optimal culture condition is obtained. At the optimal culture condition (pH 7.0, a oxygen concentration 4.0%, C: C (mtartaric acid: msuccinic acid) ratio 1:2 and NaNO3 100 mg l-1), the magnetic cells concentration is promoted to 6.5×107 cells ml-1, approximately 8.3% higher than that under the initial conditions. The pH value of medium is very important factor for magnetic cells concentration. It can be proved that the orthogonal design of experiment is of 90% confidence. The results from the hysteresis of WM-1 shows that Hc = 230 Oe, Ms = 0.9 emu/g dry wt. Cells,and Mr / Ms = 0.50.
ABSTRACT
Magnetotactic bacteria can orient and migrate along ambient geomagnetic field lines because of their intracellular magnetic particles ( referred as magnetosomes) , which comprise nanometer-sized, membrane-bound crystals of the magnetic iron minerals. Magnetosome formation is a mineralization process with very strict biological controls over the accumulation, transportation and nucleation in the cell. This paper describes the current progresses of magnetosome formation and the function of proteins involved in this biomineralization process.