Objective To observe the effect of anti-tumor peptide from Musca domestica larvae on the nucleus, the mitochondrial membrane potential and apoptosis protein cysteinyl aspartic proteinase-3 (caspase-3), and apoptosis of K562 cells. Methods Hoechst33258 fluorescent staining was used to observe the fluorescence intensity under a fluorescence microscope. The peak 5 and 8 components from M. domestica larvae were incubated with the K562 cells and the fluorescence intensity of the K562 cell nuclei was detected. The fluorescent probe rhodamine 123 was used to label the cells, which were observed under LSCM (laser scanning confocal microscope, LSCM) for the intracellular fluorescence intensity of the dye that reflected the mitochondrial membrane potential. And caspase-3 immuosorbent test kit and microplate were used to detect the enzyme activity of caspase-3 in K562 cells. Results It was found that the peak 5 and 8 components from M. domestica larvae, after incubation with the K562 cells, increased the fluorescence intensity of some K562 nuclei, suggesting the occurrence of apoptosis of K562 cells. The fluorescence intensity of the K562 cells incubated with the peak 5 and 8 components from M. domestica larvae and labeled with rhodamine 123 was significantly lower than that of the cells in the control group (t₁=21.30, t₂=196.23, P<0.05), which indicated that the anti-tumor peptide was able to reduce the mitochondrial membrane potential of K562 cells. Also, the content of caspase-3 in the cells in the test group was significantly higher than that in the cells in the control group(t₁=146.92, t₂= 189.56, P<0.05), which suggested that the antitumor peptide could contribute to apoptosis of the K562 cells. Conclusion The anti-tumor peptides in peak 5 and 8 components can damage the cell nucleus, leading to apoptosis of K562 by reducing the mitochondrial membrane potential, activating the caspase-3, and interfering with the physiological function of the cells.

Objective To investigate the effect of Musca domestica larva antimicrobial peptides on the cell membrane of tumor cells K562. Methods Antimicrobial peptides of M. domestica larvae with inhibition activity to K562 were sieved, through some processes that induced by acupuncture with Escherichia coli induction, isolated and purified by trituration, centrifuga1ization, solid phase extraction (SPE) and reversed-phase high-performance liquid chromatography (RP-HPLC), detected activity by MTT colorimetric method and observed light microscope. After treatment with different concentrations of peaks 5 and 8, the viability, morphological changes, morphological changes, membrane fluorescein leakage and destruction of K562 cells were detected by trypan blue excluding test, optical microscope and fluorescence microscope, spectrofluorophotometer, laser confocal microscope (LSCM), respectively. Results Low concentrations (＜50 μ g/ml) of M. domestica antimicrobial peptides resulted in intact viability, little change of cellular structure, a little of fluorescein leakage [(18.95±0.05)-(22.49±0.68)] and few destruction in K562 cells; however, high concentrations (≥50 μg/ml) of M. domestica antimicrobial peptides induced lower viability, cellular form change increased gradually, a great deal of fluoresceinleakage [(62.77±4.08)-(70.81±0.18)], even macromolecular fluorescent element Dextran-FITC could leak through. Conclusion There is a concentration threshold of M. domestica larvae antimicrobial peptides on K562 cell membrane. Low concentrations of M. domestica larvae antimicrobial peptides can cause the membrane leakage increasing of cell membrane, high concentrations can lead to severe damage of cell membrane, respectively. The antimicrobial peptides inhibit the growth of K562 cells through directly killing the cells, and the mechanism is that firstly damage the membrane function, then may expand the holes or inhibit the growth by other ways after entering the cells.

Objective To assess the effects of antimicrobial peptides of Tenebrio molitor Linnaeus on K562 cells, and to compare the inhibitory effects of these peptides and of hydroxyurea on K562 cell proliferation. Methods A flow cytometry was employed to identify the anti-K562 effects of molitor antimicrobial peptides. Five parallel concentrations of the two agents were set up for comparison, and their K562 inhibition rates at different concentrations were determined using the MTT colorimetric assay. The regression equation and IC₅₀ were computed using the SPSS software based on the relations between the concentration and inhibition rates. Results The proportion of cells in G₀/G₁ and G₂/M phase increased, and that of cells in S phase decreased. Statistical differences were only noticed by comparing cells in G₀/G₁ and S phases and the control group (P＜0.01), indicating that antibacterial peptides inhibited DNA synthesis in S phase by G₀/G₁ phase arrest. The IC₅₀ of antibacterial peptides and hydroxyurea were 29.98 and 3644.45 μg/ml, respectively. Conclusion The anti-K562 activity of antibacterial peptides, a result of cell cycle impairment, noticeably outstripped the inhibitory effects of hydroxyurea on K562 cell proliferation. These peptides have a good prospect for practical application in future.

【Abstract】 Objective To isolate and purify the antimicrobial peptides with anti-tumor cell K562 activity from the Tenebrio molitor Linnaeus larvae. Methods Antimicrobial peptides of Tenebrio molitor L.larvae induced by ultrasonic waves were isolated and purified by trituration，centrifuga1ization，solid phase extraction (SPE) and reversed-phase high-performance liquid chromatography (RP?HPLC). Then the antimicrobial peptides with anti-K562 activity were sieved by MTT colorimetric method and light microscope observation. Results Supernatant eluted with 10%, 30%, 80% acetonitrile (ACN) in aqueous solution by solid phase extraction, of which, only 80% was active (P＜0.01). Five anti-tumor peaks appeared after purification by RP-HPLC, which all had strong activity (P＜0.01). Only 9 and 4 peaks could initially identified as antimicrobial peptides, the others still need to be proved. Conclusion There are antimicrobial peptides and anti-ba

【Abstract】 Objective To observe the injury of the antimicrobial peptides with anti-Toxoplasma activity isolated from housefly larvae on the DNA of T.gondii tachyzoites. Methods The antimicrobial peptides of housefly larvae were induced largely by infection and injury, which were isolated and purified by trituration, centrifugalization and column chromatography. Then the antimicrobial peptides with anti-Toxoplasma activity were sieved by methyl thiazolyl tetrazolium colorimetric method and haemacytometry. The DNA contents of T.gondii tachyzoites were detected by flow cytometry （FCM）.  Results From the bar chart of DNA contents, it showed that the difference of distribution between the control group and the experimental group, and tachyzoites in the experimental group were fewer than that in the control group. The tachyzoites in M1 phase were fewer than that in M2 phase in the control group, but the condition was on the contrary in the antimicrobial peptide group. Furthermore, the peak in the M1 stage had an obvious antedisplacement.  Conclusion The antimicrobial peptide isolated from housefly larvae could kill T.gondii by inhibiting the synthesis of DNA.

Objective Isolate and purify the antimicrobial peptides with anti- Toxoplasma activity from the haemlymph of Musca domestica pupa. Methods The antimicrobial peptide of M.domestica pupa were produced largely by infection and injury,which were isolated and purified by trituration, centrifugalization and column chromatography of AKTA ^TM purifier. Then the antimicrobial peptides with anti- Toxoplasma activity were selected by haemacytometry and MTT colorimetric method. Results It was found that there was a ultraviolet absorption peak at 280 nm when retention volume was 9.4 ml through Resource S cationic exchange column chromatography, which had anti- Toxoplasma activity. This protein was collected and purified further with Superdex G75 gel column chromatography. And there were six ultraviolet absorption peaks at 280 nm through Superdex G75 gel column chromatography, and the sixth one had anti- Toxoplasma activity. Conclusion There was an antimicrobial peptide with anti- Toxoplasma activity in the haemlymph of M.domestica pupa.

Objective In this paper,the action of the antimicrobial peptide of adult housefly ( Musca domestica) against some tumor cell was investigated by Flow Cytometer(FCM). Methods The antimicrobial peptides from adult housefly was induced by Escherichia coli with a needle and was isolated and purified by grinding,centrifugalizing and chromatographing,the action of the peptide against tumor cells 109,K562,Daudi and T24 was observed by FCM. Results The present study demonstrated that the peptides could kill above four kinds of tumor cells to some extent,and M1 were all above 85%. Conclusion The antitumor action of antimicrobial peptide of adult housefly could make it possible to develop a new kinds of anti-tumor drug.

Objective To compare the two mothods of isolating the antimicobial peptides from Musca domestica larvae.Mothods Musca domestica larvae were infected with Escherichia coli by a sting,then the antimicrobial peptides were extracted from the insect.After that,the antimicrobial peptides were isolated by grinding,sephadex(G-50) gel filtration.The last,the anticancer activity of the peptides worked upon K562 cell and lymph cell were detected by Flow cytometer(FCM).Results The two kinds of peptides from Musca domestica isolated by the different methods could kill K562 cell to some extent,but they are different in working upon normal cell.Physiological saline influence cell less than the buffer.Conclusion(Buffer could) make a high osmotic pressure and impel cell to death;physiological saline(don't) do as the buffer.

Objective To research the anti-Toxoplasma activity of antimicrobial peptides isolated from Musca domestica. Methods Inoculating larva of housefly with bacterium by sting to promote it to bring about the antimicrobial peptides. Results The anticicrobial peptides extracted from M.domestica could kill the trophozoite of Toxoplasma gondii. Conclusion The antimicrobial peptides extracted from M.domestica have anti-Toxoplasma activity.

IEF/SDS-PAGE was used to analyze the peptides of deltamethrin-resistant and susceptible strains of Musca domestica (L.).IEF/SDS-PAGE revealed difference between the pupae of resistance and that of control strains.A special peptide was found in control strain.The results indicated that insecticides could lead to quality and quantity changes in resistant houseflies.

The pharyngenal armatures of the sandflies are one of the most important taxonomiccharacters.In this paper, four groups of phsryngenal armature in female Phlebotomus chinensis collectedfrom different regions were studied by scanning electron microscopy method.The observation showedthat there were no obvious differences in the four groups and these sandflies belonged to one species.