The practice of phage therapy, which uses bacterial viruses(phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed ...The practice of phage therapy, which uses bacterial viruses(phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice. Conventionally, phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection. Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins. Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections, suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments. Antibacterial therapies, whether phage-or antibiotic-based, each have relative advantages and disadvantages; accordingly, many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection. Although much about phages and human health is still being discovered, the time to take phage therapy serious again seems to be rapidly approaching.展开更多
This study of renaturation by dilution and size exclusion chromstography(SEC) addition of urea to improve yield as well as the initial and final protein concentrations showed that although urea decreased the rate of l...This study of renaturation by dilution and size exclusion chromstography(SEC) addition of urea to improve yield as well as the initial and final protein concentrations showed that although urea decreased the rate of lysozyme refolding,it could suppress protein aggregation to sustain the pathway of correct refolding at high protein concentration;and that there existed an optimum urea concentration in renaturation buffer.Under the above conditions,lysozyme was successfully refolded from initial concentration of up tp 40 mg/mL by dilu-tion and 100 mg/mL by SEC,with the yield of the former being more than 40% and that of the latter being 34.8%.Especislly,under the condition of 30 min iterval time,i.e.τ>2(tR2-tR1),the efficiency was increased by 25% and the renaturation buffer could be recycled for SEC refolding in continuous operation of downstream process.展开更多
AIM: To evaluate the protective effect of lysozyme chloride on betel quid chewing (BQC) aggravated gastric oxidative stress and hemorrhagic ulcer in rats with diabetes mellitus (DM).METHODS: Male Wistar rats were chal...AIM: To evaluate the protective effect of lysozyme chloride on betel quid chewing (BQC) aggravated gastric oxidative stress and hemorrhagic ulcer in rats with diabetes mellitus (DM).METHODS: Male Wistar rats were challenged intravenously with streptozotocin (65 mg/kg) to induce DM. Rats were fed with regular pellet food or BQC-containing diets. After 90 d, rats were deprived of food for 24 h. Rat stomachs were irrigated for 3 h with normal saline or simulated gastric juice. Rats were killed and gastric specimens were harvested.RESULTS: An enhancement of various gastric ulcerogenic parameters, including acid back-diffusion, mucosal lipid peroxide generation, as well as decreased glutathione levels and mucus content, were observed in DM rats. After feeding DM rats with BQC, an exacerbation of these ulcerogenic parameters was achieved. Gastric juice caused a further aggravation of these ulcerogenic parameters. Daily intragastric lysozyme chloride dose-dependently inhibited exacerbation of various ulcerogenic parameters in those BQC-fed DM rats.CONCLUSION: (1) Gastric juice could aggravate both DM and BQC-fed DM rat hemorrhagic ulcer; (2) BQC exacerbated gastric hemorrhagic ulcer in DM rats via enhancing oxidative stress and reducing defensive factors; (3) lysozyme chloride effectively protected BQC aggravated gastric damage in DM rats.展开更多
Oxidative refolding of the denatured/reduced lysozyme was investigated by using weak-cation exchange chromatography (WCX). The stationary phase of WCX binds to the reduced lysozyme and prevented it from forming interm...Oxidative refolding of the denatured/reduced lysozyme was investigated by using weak-cation exchange chromatography (WCX). The stationary phase of WCX binds to the reduced lysozyme and prevented it from forming intermolecular aggregates. At the same time urea and ammonium sulfate were added to the mobile phase to increase the elution strength for lysozyme. Ammonium sulfate can more stabilize the native protein than a common eluting agent, sodium chloride. Refolding of lysozyme by using this WCX is successfully. It was simply carried out to obtain a completely and correctly refolding of the denatured lysozyme at high concentration of 20.0 mg/mL.展开更多
Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties ...Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm^(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.展开更多
[Objective] This study was to investigate the preventive effect of cecropin and lysozyme on skin fester disease in Trionyx sinensis.[Method]By employing intramuscular injection method,the preventive effect of mixtures...[Objective] This study was to investigate the preventive effect of cecropin and lysozyme on skin fester disease in Trionyx sinensis.[Method]By employing intramuscular injection method,the preventive effect of mixtures of cecropin( 10 mg/kg) and lysozyme( 10 mg/kg) and of cecropin( 6 mg/kg) and lysozyme( 5 mg/kg) were challenged on Aeromonas encheleia-caused skin fester disease in T.sinensis.The mortality and relative percent survival were used evaluate the preventive effect of different drugs.The serum agglutination titer,cytophagocytosis and bactericidal activity were detected to compare the effect of drugs on the immunity and disease resistance of T.sinensis.[Result]The residue concentrations of gentamicin and lysozyme in serum were compared to evaluate the side effect of drugs used challenged.The results showed that combined use of cecropin and lysozyme gave the best preventive effect and immunity in T.sinensis,with an extremely significant difference from other treatments( P < 0.01).Analysis of drug residue in serum indicated that lysozyme was completely metabolized 6 days after medication,while gentamicin residue was still observed 12 days later.[Conclusion] The combined application of cecropin and lysozyme showed better preventive effect than antibiotics in fester disease of T.sinensis.Moreover,no drug residue and side effect were observed in the combined use treatment.This method avoids the side effect of antibiotics,worthy of extension at commercial scale.展开更多
Lysozymes can hydrolyze bacteria and play an important role in animal digestion and innate immunity. The cDNA of a chicken-type lysozyme gene (Mdlys) was cloned from housefly (Musca domestica). The 484 bp full-length ...Lysozymes can hydrolyze bacteria and play an important role in animal digestion and innate immunity. The cDNA of a chicken-type lysozyme gene (Mdlys) was cloned from housefly (Musca domestica). The 484 bp full-length cDNA contains a 426 bp open reading frame (ORF) that encodes MdLys of 141 amino acids. Phylogenetic analysis indicated that the MdLys was similar to chicken-type lysozymes. Spatio-temporal expression of Mdlys was analyzed by RT-PCR. The Mdlys transcript can be detected in both midgut and fat body and was expressed at a relatively lower level at the embryo stage. Mdlys mRNA was upregulated 2 h post bacterial challenge, main-tained for 2 to 6 h, and slightly declined from 12 to 24 h post-injection. Western blot analysis showed that MdLys was highly expressed in midgut and was also detected in the hemolymph and fat body. MdLys expression was slightly increased in midgut after challenging with Escherichia coli or Staphylococcus aureus. Its expression was also slightly increased in the fat body after challenging with S. aureus, but no obvious change occurred after E. coli challenge. MdLys expression in the hemolymph was not affected by bacterial challenge. In the developmental stages, MdLys expression levels had no obvious change from the first instar to the pupae stage. There was also no varia-tion under 24 h starvation stress. Recombinant MdLys displayed inhibitory activity against Gram-negative and Gram-positive bacteria. Together, these results suggest that MdLys may play an important role in the innate immunity of houseflies.展开更多
Human lysozyme (HL) inhibits Fusarium oxysporum (FocR4) growth in vitro. To obtaintransgenic bananas (Musa spp.) that are resistant to Panama wilt (F. oxysporum), we introduced an HL genethat is driven by a constituti...Human lysozyme (HL) inhibits Fusarium oxysporum (FocR4) growth in vitro. To obtaintransgenic bananas (Musa spp.) that are resistant to Panama wilt (F. oxysporum), we introduced an HL genethat is driven by a constitutive cauliflower mosaic virus 35S promoter into the banana via Agrobacterium-mediated transformation. PCR confirmed that 51 transgenic plants were obtained. The development ofPanama wilt symptoms were examined after the plants had been grown in pots. The non-transgenic plantsdeveloped typical fusarium symptoms 60 d after FocR4 inoculation, whereas 24 of 51 transgenic plants remained healthy. The transgenic banana plants that showed resistance to FocR4 in the pots were then planted in a field that was heavily infected with FocR4 for further investigation. Eleven of 24 plants developed symptoms before bud emergence; another 11 plants showed symptoms after bud emergence and the remaining two plants, H-67 and H-144, remained healthy and were able to fruit. Northern blotting analysisdemonstrated that H-67 and H-144, bearing the strongest resistance to Panama wilt, had the highest level ofHL expression and that the expression of HL was well correlated with the FocR4 resistance of transgenicplants. We conclude that Agrobacterium-mediated transformation, with the assistance of particlebombardment, is a powerful approach for banana transformation and that a transgenic HL gene can causeresistance of the crop to FocR4 in the field.展开更多
With their hollow morphology and large openings, the as-synthesized porous silica nano-tubes (NTPS), prepared through a sol-gel routine by using nano-sized needle-shaped CaCO3 particles as templates, were used as host...With their hollow morphology and large openings, the as-synthesized porous silica nano-tubes (NTPS), prepared through a sol-gel routine by using nano-sized needle-shaped CaCO3 particles as templates, were used as host for enzyme immobilization. Bioimmobilization study showed that enzyme molecules could not only be adsorbed on the external surface of NTPS but also entrapped in their inner hollow cores, leading to higher enzyme loading capacities of NTPS (more than 350 mg/g silica) in a shorter time, as compared to common porous silica (less than 50 mg/g) and most conventional mesoporous silica materials (less than 100 mg/g).展开更多
Dear Editor,Dense core vesicles(DCVs)are a class of secretory organelle present in a range of different cell types,including neurons,endocrine cells,such as adrenal chromaffin cells and isletβ-cells,and other secreto...Dear Editor,Dense core vesicles(DCVs)are a class of secretory organelle present in a range of different cell types,including neurons,endocrine cells,such as adrenal chromaffin cells and isletβ-cells,and other secretory cells,such as intestinal Paneth cells(Kim et al.,2006).Cargos are packed into immature DCVs as they emerge from the trans-Golgi network.展开更多
基金Supported by Winkler Bacterial Overgrowth Research Fund(in part)
文摘The practice of phage therapy, which uses bacterial viruses(phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice. Conventionally, phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection. Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins. Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections, suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments. Antibacterial therapies, whether phage-or antibiotic-based, each have relative advantages and disadvantages; accordingly, many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection. Although much about phages and human health is still being discovered, the time to take phage therapy serious again seems to be rapidly approaching.
文摘This study of renaturation by dilution and size exclusion chromstography(SEC) addition of urea to improve yield as well as the initial and final protein concentrations showed that although urea decreased the rate of lysozyme refolding,it could suppress protein aggregation to sustain the pathway of correct refolding at high protein concentration;and that there existed an optimum urea concentration in renaturation buffer.Under the above conditions,lysozyme was successfully refolded from initial concentration of up tp 40 mg/mL by dilu-tion and 100 mg/mL by SEC,with the yield of the former being more than 40% and that of the latter being 34.8%.Especislly,under the condition of 30 min iterval time,i.e.τ>2(tR2-tR1),the efficiency was increased by 25% and the renaturation buffer could be recycled for SEC refolding in continuous operation of downstream process.
基金Supported by a grant (NSC 91-2320-B006-103) from National Sciences Council of Taiwan, China
文摘AIM: To evaluate the protective effect of lysozyme chloride on betel quid chewing (BQC) aggravated gastric oxidative stress and hemorrhagic ulcer in rats with diabetes mellitus (DM).METHODS: Male Wistar rats were challenged intravenously with streptozotocin (65 mg/kg) to induce DM. Rats were fed with regular pellet food or BQC-containing diets. After 90 d, rats were deprived of food for 24 h. Rat stomachs were irrigated for 3 h with normal saline or simulated gastric juice. Rats were killed and gastric specimens were harvested.RESULTS: An enhancement of various gastric ulcerogenic parameters, including acid back-diffusion, mucosal lipid peroxide generation, as well as decreased glutathione levels and mucus content, were observed in DM rats. After feeding DM rats with BQC, an exacerbation of these ulcerogenic parameters was achieved. Gastric juice caused a further aggravation of these ulcerogenic parameters. Daily intragastric lysozyme chloride dose-dependently inhibited exacerbation of various ulcerogenic parameters in those BQC-fed DM rats.CONCLUSION: (1) Gastric juice could aggravate both DM and BQC-fed DM rat hemorrhagic ulcer; (2) BQC exacerbated gastric hemorrhagic ulcer in DM rats via enhancing oxidative stress and reducing defensive factors; (3) lysozyme chloride effectively protected BQC aggravated gastric damage in DM rats.
基金This work is supported by the National Natural Science Foundation(No.20175016).
文摘Oxidative refolding of the denatured/reduced lysozyme was investigated by using weak-cation exchange chromatography (WCX). The stationary phase of WCX binds to the reduced lysozyme and prevented it from forming intermolecular aggregates. At the same time urea and ammonium sulfate were added to the mobile phase to increase the elution strength for lysozyme. Ammonium sulfate can more stabilize the native protein than a common eluting agent, sodium chloride. Refolding of lysozyme by using this WCX is successfully. It was simply carried out to obtain a completely and correctly refolding of the denatured lysozyme at high concentration of 20.0 mg/mL.
基金Supported by the National Natural Science Foundation of China(21476086)Guangdong Natural Science Foundation(2014A030312007)
文摘Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm^(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.
文摘[Objective] This study was to investigate the preventive effect of cecropin and lysozyme on skin fester disease in Trionyx sinensis.[Method]By employing intramuscular injection method,the preventive effect of mixtures of cecropin( 10 mg/kg) and lysozyme( 10 mg/kg) and of cecropin( 6 mg/kg) and lysozyme( 5 mg/kg) were challenged on Aeromonas encheleia-caused skin fester disease in T.sinensis.The mortality and relative percent survival were used evaluate the preventive effect of different drugs.The serum agglutination titer,cytophagocytosis and bactericidal activity were detected to compare the effect of drugs on the immunity and disease resistance of T.sinensis.[Result]The residue concentrations of gentamicin and lysozyme in serum were compared to evaluate the side effect of drugs used challenged.The results showed that combined use of cecropin and lysozyme gave the best preventive effect and immunity in T.sinensis,with an extremely significant difference from other treatments( P < 0.01).Analysis of drug residue in serum indicated that lysozyme was completely metabolized 6 days after medication,while gentamicin residue was still observed 12 days later.[Conclusion] The combined application of cecropin and lysozyme showed better preventive effect than antibiotics in fester disease of T.sinensis.Moreover,no drug residue and side effect were observed in the combined use treatment.This method avoids the side effect of antibiotics,worthy of extension at commercial scale.
基金supported by the National High Technology Research and Development Program of China (863 Program) (No. 2007AA09Z425 and 2006AA100311)the Ph.D. Program Foundation of the Ministry of Education of China (No. 20060422034).
文摘Lysozymes can hydrolyze bacteria and play an important role in animal digestion and innate immunity. The cDNA of a chicken-type lysozyme gene (Mdlys) was cloned from housefly (Musca domestica). The 484 bp full-length cDNA contains a 426 bp open reading frame (ORF) that encodes MdLys of 141 amino acids. Phylogenetic analysis indicated that the MdLys was similar to chicken-type lysozymes. Spatio-temporal expression of Mdlys was analyzed by RT-PCR. The Mdlys transcript can be detected in both midgut and fat body and was expressed at a relatively lower level at the embryo stage. Mdlys mRNA was upregulated 2 h post bacterial challenge, main-tained for 2 to 6 h, and slightly declined from 12 to 24 h post-injection. Western blot analysis showed that MdLys was highly expressed in midgut and was also detected in the hemolymph and fat body. MdLys expression was slightly increased in midgut after challenging with Escherichia coli or Staphylococcus aureus. Its expression was also slightly increased in the fat body after challenging with S. aureus, but no obvious change occurred after E. coli challenge. MdLys expression in the hemolymph was not affected by bacterial challenge. In the developmental stages, MdLys expression levels had no obvious change from the first instar to the pupae stage. There was also no varia-tion under 24 h starvation stress. Recombinant MdLys displayed inhibitory activity against Gram-negative and Gram-positive bacteria. Together, these results suggest that MdLys may play an important role in the innate immunity of houseflies.
文摘Human lysozyme (HL) inhibits Fusarium oxysporum (FocR4) growth in vitro. To obtaintransgenic bananas (Musa spp.) that are resistant to Panama wilt (F. oxysporum), we introduced an HL genethat is driven by a constitutive cauliflower mosaic virus 35S promoter into the banana via Agrobacterium-mediated transformation. PCR confirmed that 51 transgenic plants were obtained. The development ofPanama wilt symptoms were examined after the plants had been grown in pots. The non-transgenic plantsdeveloped typical fusarium symptoms 60 d after FocR4 inoculation, whereas 24 of 51 transgenic plants remained healthy. The transgenic banana plants that showed resistance to FocR4 in the pots were then planted in a field that was heavily infected with FocR4 for further investigation. Eleven of 24 plants developed symptoms before bud emergence; another 11 plants showed symptoms after bud emergence and the remaining two plants, H-67 and H-144, remained healthy and were able to fruit. Northern blotting analysisdemonstrated that H-67 and H-144, bearing the strongest resistance to Panama wilt, had the highest level ofHL expression and that the expression of HL was well correlated with the FocR4 resistance of transgenicplants. We conclude that Agrobacterium-mediated transformation, with the assistance of particlebombardment, is a powerful approach for banana transformation and that a transgenic HL gene can causeresistance of the crop to FocR4 in the field.
基金Project supported by the National Natural Science Foundation of China （Nos. 20132020 and 20175026） and Henan Academic Foundation of Science and Technology.
基金The authors gratefully acknowledge funding from the Russian Foundation for Basic Research （project No. 16- 54-53033 to VYK and MVT）, Grant of Russian Federation President （MK-6278.2015.4 to ONY）. IMD gratefully acknowledge funding from the Russian Science Foundation （project No.16-14-10067） for support in the model development and immunological study. TMB was supported by a grant funded jointly by the Biotechnology and Biological Sciences Research Council, the Department For Environment, Food And Rural affairs, the Economic and Social Research Council, the Forestry Commission, the Natural Environment Research Council and the Scottish Government, under the Tree Health and Plant Biosecurity Initiative.
文摘With their hollow morphology and large openings, the as-synthesized porous silica nano-tubes (NTPS), prepared through a sol-gel routine by using nano-sized needle-shaped CaCO3 particles as templates, were used as host for enzyme immobilization. Bioimmobilization study showed that enzyme molecules could not only be adsorbed on the external surface of NTPS but also entrapped in their inner hollow cores, leading to higher enzyme loading capacities of NTPS (more than 350 mg/g silica) in a shorter time, as compared to common porous silica (less than 50 mg/g) and most conventional mesoporous silica materials (less than 100 mg/g).
基金supported by the National Natural Science Foundation of China (81570504, 31471337)
文摘Dear Editor,Dense core vesicles(DCVs)are a class of secretory organelle present in a range of different cell types,including neurons,endocrine cells,such as adrenal chromaffin cells and isletβ-cells,and other secretory cells,such as intestinal Paneth cells(Kim et al.,2006).Cargos are packed into immature DCVs as they emerge from the trans-Golgi network.
