Staphylococcus aureus (S. aureus) is a bacterial pathogen for humans and animals. These bacteria can resist against many antibiotics and this resistance constitute an alarming worldwide human health threat due to the ...Staphylococcus aureus (S. aureus) is a bacterial pathogen for humans and animals. These bacteria can resist against many antibiotics and this resistance constitute an alarming worldwide human health threat due to the morbidity and mortality. Phage therapy is one of the alternative treatments. The aim of this study was to isolate and characterize lytic phages of S. aureus from different wastewater sources in Bobo-Dioulasso, Burkina Faso. Eight strains of S. aureus were isolated from different clinical samples and were used to isolate phages. The isolation and host range of phages were done by the spot test. Phages were purified by the double-layer method. Similar phages after the determination of the host range were characterized using restriction enzymes. A total of 27 phages were obtained after isolation and purification. Nine of the 27 isolates reported a broad host range (≥67%). The results of enzymatic digestion allowed to consider that all phage isolates that presented the same host range and the same genetic fingerprint are the same phage strain;whereas phages that presented the same host range and different genetic fingerprints are different phage strains. Thus, a total of 15 distinct phages isolates specific to S. aureus were characterized. This study highlighted the abundance and lytic capacity of phages isolated from wastewater from Bobo-Dioulasso’s environment against clinical strains of S. aureus. The lytic capacity of these Staphyphages could be an effective alternative tool to combat bacteria multi-resistance.展开更多
As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated...As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study.展开更多
There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of ‘bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, ...There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of ‘bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well(Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specifi c disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay(Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes–from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.展开更多
All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing...All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing bacteria in an algal bloom, it is difficult to isolate the alga-lysing bacteria by existing methods. In this paper, two algae-lysing bacterial strains, P01 and P03, have been isolated from a biosystem immobilized on a sponge that was highly effective in removing algae and microcystins. Their lysing modes and effects on Microcystis aeruginosa have been studied. The results show that the degradation processes of these two strains for M. aeruginosa accorded with a first-order reaction model when the chlorophylla concentration was in the range from 0 to 1000 μgL-1. The degradation rate constants were 0.1067, 0.1274 and 0.2792 for P01 and0.0683, 0.0744 and 0.028 97 for P03, when the bacterial densities were 8.6 × 105, 8.6 × 106 and 8.6 × 107cells mL-1 respectively. Moreover, the two bacterial strains had favourable lytic effects not only on M. aeruginosa , but also on Chlorella and Scene-desmus. Their lytic effect on M. aeruginosa did not require physical cell to cell contact, but proceeded by the production of an extracellular product. The bacterial strains were identified as Bacillus species by PCR amplification of the 16S rRNA gene, BLAST analysis, and comparison with sequences in the GenBank nucleotide database.展开更多
A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path“hyperploid progression-mediated death”targeting retinoblastoma(Rb)or p53-mutants defective i...A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path“hyperploid progression-mediated death”targeting retinoblastoma(Rb)or p53-mutants defective in G1 DNA damage checkpoint.The genetic basis of human cancers was uncovered through the cloning of the tumor suppressor Rb gene.It encodes a nuclear DNA-binding protein whose self-interaction is regulated by cyclin-dependent kinases.A 3Dstructure of Rb dimer is shown,confirming its multimeric status.Rb assumes a central role in cell cycle regulation and the“Rb pathway”is universally inactivated in human cancers.Hyperploidy refers to a state in which cells contain one or more extra chromosomes.Hyperploid progression occurs due to continued cell-cycling without cytokinesis in G1 checkpoint-defective cancer cells.The evidence for the triggering of hyperploid progression-mediated death in RBmutant human retinoblastoma cells is shown.Hence,the very genetic mutation that predisposes to cancer can be exploited to induce lethality.The discovery helped to establish the principle of targeted cytotoxic cancer therapy at the mechanistic level.By triggering the lytic path,targeted therapy with tumor specificity at the genetic level can be developed.It sets the stage for systematically eliminating side effects for cytotoxic cancer therapy.展开更多
Exogenous Vitreoscilla globin gene (vgb), lytic genes of phage A with S amber mutation (S-RRz) and poly(B-hydroxybutyrate) (PHB) biosynthetic genes (phbCAB) were cloned into a same Escherichia coli cell, simultaneousl...Exogenous Vitreoscilla globin gene (vgb), lytic genes of phage A with S amber mutation (S-RRz) and poly(B-hydroxybutyrate) (PHB) biosynthetic genes (phbCAB) were cloned into a same Escherichia coli cell, simultaneously or respectively. Six novel strains containing phbCAB and vgb with or without lytic genes were constructed. Strain VG1 (pTU14), in which vgb, phbCAB and S-RRz could all be successfully expressed, has superior characteristics in cell growth and PHB accumulation, while the results of strains containing vgb and phbCAB without S- RRz were not better than that of strains harbored ph&CAB only. The simultaneous expression of vgb and S- RRz in the recombinant VG1 (pTU14) showed a great potential for low-cost production of PHB.展开更多
Fusarium solani is a necrotrophic parasitic fungus that causes wilt in some plants, causing severe economic losses in some areas of the country. The objective of this work was to analyze the induction of extracellular...Fusarium solani is a necrotrophic parasitic fungus that causes wilt in some plants, causing severe economic losses in some areas of the country. The objective of this work was to analyze the induction of extracellular lytic enzymes produced by a strain of F. solani, isolated from a culture of tomato, in Villa de Arista, S.L.P. México. Polygalacturonase activity has a greater induction time at 10 days, and the xylanase has two times higher activity at 8 and 13 days of incubation at 28?C. Also, the xylanase activities A and B were very stable at 4?C. After 7 days of incubation, it has an activity of 100% and 96%, respectively, while polygalacturonase retains 61% of its initial activity. Both activities are better induced with glutamate and urea as nitrogen sources respectively, and both exhibit an initial pH optimum of 5.5. Finally, we didn’t find cellulase activity in the analyzing conditions.展开更多
Non-secretory myeloma is a rare variety of multiple myeloma. Classical techniques of chronic secretion’s research don’t find any immunoglobulin monoclonal peak in the patient’s blood. Lytic bone lesions are rare in...Non-secretory myeloma is a rare variety of multiple myeloma. Classical techniques of chronic secretion’s research don’t find any immunoglobulin monoclonal peak in the patient’s blood. Lytic bone lesions are rare in this type of myeloma. We report the case of a patient in whom we confirmed multiple myeloma by bone marrow aspiration and we have classified stage III of Durie and Salmon in view of hypercalcemia, anemia, and lytic lesions observed. However, we could not isolate a secretion of monoclonal immunoglobulin in blood but urinary secretion was evident by proteinuria and urinary light chains. The radiographs of our patient found diffuse osteolysis and practice of sternal puncture confirmed multiple myeloma. Our case is original because of rarity on non secretory myeloma particularly with diffuse osteolytic lesion.展开更多
Cystic angiomatosis is a rare, benign, multifocal disorder of bone and viscera. Angiomatous deposits result in bone lysis and organ dysfunction. Bony cystic lesions occur in the axial and proximal appendicular skeleto...Cystic angiomatosis is a rare, benign, multifocal disorder of bone and viscera. Angiomatous deposits result in bone lysis and organ dysfunction. Bony cystic lesions occur in the axial and proximal appendicular skeleton. Lesions may cause bone pain or pathological fracture. Diagnosis is difficult, of exclusion and demands a biopsy. The prognosis varies upon whether the lesions are solely skeletal or there is visceral involvement. A 71-year-old man reports increasing symptoms of painful swelling in the right thoracic wall for over a month. The swelling was bony hard in consistency. Except for his bony swelling, the patient’s physical examination was within normal limits, as were all his laboratory studies. X-ray imagery showed multicystic expansive lytic areas involving the right ribs. Computerized tomography, magnetic resonance imagery and gallium bone scan revealed lytic lesions of multiple right ribs, and cervical, dorsal, lumbar and sacrum iliac spine. A right rib biopsy has shown a cystic formation with endothelial walls. Five years later, the patient remained stable, with no clinical, laboratory or imagilogic progression of disease and without visceral involvement. This case is presented in his rarity and differential diagnosis challenge.展开更多
In order to effectively use of phages as antimicrobial agents for controlling multidrug-resistant E.coli,it is important to understand phage biology.The isolation and research of novel bacteriophages are urgently need...In order to effectively use of phages as antimicrobial agents for controlling multidrug-resistant E.coli,it is important to understand phage biology.The isolation and research of novel bacteriophages are urgently needed for food safety and animal health.Phage is considered as a novel alternative antibacterial agents and a new way of prevent,control and treat pathogens.In this paper,we isolated and characterized a novel lytic phage from chicken samples,named vB_EscP_vE20(in brief vE20).We identified vE20 as belonging to the Podoviridae family through morphological and phylogenetic analysis.It had lytic activities against 24 out of 51 different serotypes of clinical E.coli strains,interestingly it also can lyse Salmonella species,such as Salmonella Enteritidis(S.Enteritidis)and Samonella Typhimu-rium(S.Typhimurium).One step growth curve showed that the latent period and lysis period was 10 min and 60 min,respectively.The burst size of vE20 was about 60 PFU/cell.The phage vE20 survived in a wide range of temperatures(30-60℃)and pH(3-11).The whole genome size of phage vE20 is 77,938 bps,which is double stranded DNA.There are 121 Open reading frame(ORFs)in total,and the GC-content is 42.17%,without virulence-associated,antibiotic and lysogeny related genes.Phage vE20 has high bactericidal activity in killing E.coli EXG20-1 in cultures containing 4×10^(9) cfu/mL in several MOIs culture.The results revealed the promising potential of phage vE20 as attractive candidates for the control of E.coli infections.展开更多
Long-term and stable preservation of bacteriophages is of crucial importance.Although many efforts have been made in the past decades to explore the influence of external factors on bacteriophage preservation,there is...Long-term and stable preservation of bacteriophages is of crucial importance.Although many efforts have been made in the past decades to explore the influence of external factors on bacteriophage preservation,there is still little understanding,and a systematic description is lacking.In this study,we explored the influence of different factors on the preservation of lytic bacteriophage VP3,one of the typing bacteriophages of Vibrio cholerae O1 biotype El Tor,and attempted to optimize its preservation.We examined external factors,including temperature,solution,and cryoprotectant,in stable cooling/freezing conditions or alternate cooling/freezing and thawing.We found that whether in Luria-Bertani(LB)medium or SM buffer,in terms of 20-week stable cooling or freezing,−20℃ was the most damaging while 4℃,−80℃,and−196℃ were protective.Thirteen cycles of alternate cooling/freezing and thawing caused a loss in the survival rates of bacteriophages.The addition of cryoprotectant,glycerol(30%,w/v)or dimethyl sulfoxide(DMSO,10%,w/v)significantly improved the survival rates of bacteriophages preserved at−20℃.However,at 4℃,−80℃,and−196℃,the cryoprotectant effect was only slightly positive or even harmful.In summary,for bacteriophage VP3,the best preservation method is to directly preserve the bacteriophage stocks in LB medium at−80℃ or−196℃ instead of storing them in SM buffer or adding cryoprotectant.Our results provided insights into the external influencing factors on bacteriophage VP3 during preservation at low temperature and can be applied to the optimization of bacteriophage preservation in the future.展开更多
Lytic polysaccharide monooxygenases(LPMOs)are important enzymes that boost the hydrolysis of recalcitrant polysaccharides,such as chitin.They are found extensively in different insect species and are classified as aux...Lytic polysaccharide monooxygenases(LPMOs)are important enzymes that boost the hydrolysis of recalcitrant polysaccharides,such as chitin.They are found extensively in different insect species and are classified as auxiliary activities family 15(AA15)LPMOs(LPMO15).Some of them were identified from the insect midgut and proven to act on chitin.However,knowledge about their physiological roles during insect growth and development remains limited.Here,we found that midgut-specific LPMO15s are widely distributed in different insect orders,such as the orthopteran Locusta migratoria and the lepidopteran Bombyx mori.Using L.migratoria as a model insect,the function of midgut-specific LmLPMO15-3 during development was investigated.Double-stranded RNA-mediated downregulation of LmLPMO15-3 expression at the 4th or 5th instar nymph stage severely decreased the survival rate and resulted in lethal phenotypes.Hematoxylin and eosin staining results indicated that the deficient individuals exhibited incompletely digested peritrophic matrix(PM),which suggested that LmLPMO15-3 is essential for the deconstruction of the PM during molting.This study provides direct evidence of the physiological importance of a midgut-specific LPMO15 during insect development.As L.migratoria is one of the most destructive agricultural pests,LmLPMO15-3 is a potential target for pest management.展开更多
In pH 3.8 acetic acid-sodium acetate （HAC-NaAC） buffer solution, laccase exhibited a strong catalytic effect on the H2O2 oxidation of I- to form I2, and I2 combined with excess I- to form I3- that reacted with catio...In pH 3.8 acetic acid-sodium acetate （HAC-NaAC） buffer solution, laccase exhibited a strong catalytic effect on the H2O2 oxidation of I- to form I2, and I2 combined with excess I- to form I3- that reacted with cationic surfactants of tetradecyl dimethylbenzyl ammonium chloride （TDMAC） to produce the （TDMAC-I3）n association complex particles, which exhibited a strong resonance scattering （RS） peak at 468 nm. Under the chosen conditions, as the concentration of laccase activity increased, the RS intensity at 468 nm （1468 nm） increased linearly. The increased RS intensity A1468 nm was linear to laccase activity in the range of 0.08-0.96 U/mL, with a regression equation of △1468 nm =88.8 U-1.9, and a detection limit of 0.02 U/mL laccase. This proposed method was applied to detect laccase activity in waste water, with satisfactory results.展开更多
Objectives Systemic lupus erythematosus (SLE) is a multifactorial disease. Environmental factors such as viral infection(s) have been proposed as pathaetiological factors. There are particular interests in studying ly...Objectives Systemic lupus erythematosus (SLE) is a multifactorial disease. Environmental factors such as viral infection(s) have been proposed as pathaetiological factors. There are particular interests in studying lymphotropic viruses such as the Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Although previous case reports and in vitro studies suggested that they may have a role, there is no direct evidence that onset of SLE or disease exacerbation is associated with active infection by these viruses. Using the very sensitive polymerase chain reaction (PCR) technique, we tried to find out evidence of active replication of these viruses in patients with SLE. Methods Thirty-four patients with SLE were compared with matched normal controls. Eleven patients were newly diagnosed to have SLE and 18 of the 34 patients had active disease as determined by a SLE Disease Activity Index (SLEDAI) score of ≥10 at the time of study. Results Our results showed no evidence of active replication or reactivation of EBV in the leucocytes amongst the newly diagnosed SLE patients, established SLE patients, patients with SLEDAI ≥10, patients with SLEDAI <10, and control subjects. There was no evidence of CMV infection in any of the subjects studied. The IgG and IgA responses against EBV early antigen (EA) and viral capsid antigen (VCA) were also studied. The IgG and IgA responses against VCA of EBV were increased in patients with SLE when compared with controls. However, there were no differences in these responses among different subgroups of patients. The mechanism of these responses was not apparent but may represent non-specific hyperimmune responses in these patients. There were no differences in the titre of IgG and IgA against EBV EA between the patient groups and controls.Conclusion There is no direct evidence that either EBV or CMV plays a direct role in the onset and/or exacerbation of SLE.展开更多
文摘Staphylococcus aureus (S. aureus) is a bacterial pathogen for humans and animals. These bacteria can resist against many antibiotics and this resistance constitute an alarming worldwide human health threat due to the morbidity and mortality. Phage therapy is one of the alternative treatments. The aim of this study was to isolate and characterize lytic phages of S. aureus from different wastewater sources in Bobo-Dioulasso, Burkina Faso. Eight strains of S. aureus were isolated from different clinical samples and were used to isolate phages. The isolation and host range of phages were done by the spot test. Phages were purified by the double-layer method. Similar phages after the determination of the host range were characterized using restriction enzymes. A total of 27 phages were obtained after isolation and purification. Nine of the 27 isolates reported a broad host range (≥67%). The results of enzymatic digestion allowed to consider that all phage isolates that presented the same host range and the same genetic fingerprint are the same phage strain;whereas phages that presented the same host range and different genetic fingerprints are different phage strains. Thus, a total of 15 distinct phages isolates specific to S. aureus were characterized. This study highlighted the abundance and lytic capacity of phages isolated from wastewater from Bobo-Dioulasso’s environment against clinical strains of S. aureus. The lytic capacity of these Staphyphages could be an effective alternative tool to combat bacteria multi-resistance.
基金supported by the National Natural Science Foundation of China (31160121)the Yunnan Provincial Education Fund project (2013Z138)funded by the Open Research Fund Program of the State Key Laboratory of Virology of China (2013002)
文摘As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study.
文摘There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of ‘bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well(Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specifi c disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay(Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes–from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.
基金This study was supported by the Sino Japan Science Cooperative Program （Grant No.003250103） Special Funds for PhD Research Station of University （Grant No. 20020422045）Science Foundation of Shandong Province （Grant No. Z2003B01 ）.
文摘All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing bacteria in an algal bloom, it is difficult to isolate the alga-lysing bacteria by existing methods. In this paper, two algae-lysing bacterial strains, P01 and P03, have been isolated from a biosystem immobilized on a sponge that was highly effective in removing algae and microcystins. Their lysing modes and effects on Microcystis aeruginosa have been studied. The results show that the degradation processes of these two strains for M. aeruginosa accorded with a first-order reaction model when the chlorophylla concentration was in the range from 0 to 1000 μgL-1. The degradation rate constants were 0.1067, 0.1274 and 0.2792 for P01 and0.0683, 0.0744 and 0.028 97 for P03, when the bacterial densities were 8.6 × 105, 8.6 × 106 and 8.6 × 107cells mL-1 respectively. Moreover, the two bacterial strains had favourable lytic effects not only on M. aeruginosa , but also on Chlorella and Scene-desmus. Their lytic effect on M. aeruginosa did not require physical cell to cell contact, but proceeded by the production of an extracellular product. The bacterial strains were identified as Bacillus species by PCR amplification of the 16S rRNA gene, BLAST analysis, and comparison with sequences in the GenBank nucleotide database.
基金We are grateful to Tri Ngo for assistance with computer-based molecular modeling.Also acknowledged are the faculties at Johns Hopkins University,U.C.Berkeley,Baylor University,Davidson College(alma mater of United States president Woodrow Wilson,Nobel Prize 1919),Hollywood High School(alma mater of Hollywood classics actors,ex.Judy Garland in″The Wizard of Oz″),clinical staff(U.C.San Francisco),and actress in‘The Flying Nun’(Warner Bros.Pictures,Hollywood).City of Hope National Medical Center(National Comprehensive Cancer Network member)was established partly through the assistance of Hollywood's film industries(ex.Warner Bros.Pictures),supported by Hollywood’s renown figures(Frank Sinatra,Bob Hope,Ella Fitzgerald,etc.),visited by United States First Lady Eleanor(Franklin D.Roosevelt presidency),United States presidential candidate Robert F.Kennedy,Queen Elizabeth II(United Kingdom),graced by Pope John Paul II(Vatican,Italy),and supported by numerous distinguished individuals/industries.Its Beckman Research Institute was established by A.Beckman(California Institute of TechnologyBeckman Instruments).
文摘A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path“hyperploid progression-mediated death”targeting retinoblastoma(Rb)or p53-mutants defective in G1 DNA damage checkpoint.The genetic basis of human cancers was uncovered through the cloning of the tumor suppressor Rb gene.It encodes a nuclear DNA-binding protein whose self-interaction is regulated by cyclin-dependent kinases.A 3Dstructure of Rb dimer is shown,confirming its multimeric status.Rb assumes a central role in cell cycle regulation and the“Rb pathway”is universally inactivated in human cancers.Hyperploidy refers to a state in which cells contain one or more extra chromosomes.Hyperploid progression occurs due to continued cell-cycling without cytokinesis in G1 checkpoint-defective cancer cells.The evidence for the triggering of hyperploid progression-mediated death in RBmutant human retinoblastoma cells is shown.Hence,the very genetic mutation that predisposes to cancer can be exploited to induce lethality.The discovery helped to establish the principle of targeted cytotoxic cancer therapy at the mechanistic level.By triggering the lytic path,targeted therapy with tumor specificity at the genetic level can be developed.It sets the stage for systematically eliminating side effects for cytotoxic cancer therapy.
基金Supported by the National Natural Science Foundation of China (No. 29834103, 29876021).
文摘Exogenous Vitreoscilla globin gene (vgb), lytic genes of phage A with S amber mutation (S-RRz) and poly(B-hydroxybutyrate) (PHB) biosynthetic genes (phbCAB) were cloned into a same Escherichia coli cell, simultaneously or respectively. Six novel strains containing phbCAB and vgb with or without lytic genes were constructed. Strain VG1 (pTU14), in which vgb, phbCAB and S-RRz could all be successfully expressed, has superior characteristics in cell growth and PHB accumulation, while the results of strains containing vgb and phbCAB without S- RRz were not better than that of strains harbored ph&CAB only. The simultaneous expression of vgb and S- RRz in the recombinant VG1 (pTU14) showed a great potential for low-cost production of PHB.
文摘Fusarium solani is a necrotrophic parasitic fungus that causes wilt in some plants, causing severe economic losses in some areas of the country. The objective of this work was to analyze the induction of extracellular lytic enzymes produced by a strain of F. solani, isolated from a culture of tomato, in Villa de Arista, S.L.P. México. Polygalacturonase activity has a greater induction time at 10 days, and the xylanase has two times higher activity at 8 and 13 days of incubation at 28?C. Also, the xylanase activities A and B were very stable at 4?C. After 7 days of incubation, it has an activity of 100% and 96%, respectively, while polygalacturonase retains 61% of its initial activity. Both activities are better induced with glutamate and urea as nitrogen sources respectively, and both exhibit an initial pH optimum of 5.5. Finally, we didn’t find cellulase activity in the analyzing conditions.
文摘Non-secretory myeloma is a rare variety of multiple myeloma. Classical techniques of chronic secretion’s research don’t find any immunoglobulin monoclonal peak in the patient’s blood. Lytic bone lesions are rare in this type of myeloma. We report the case of a patient in whom we confirmed multiple myeloma by bone marrow aspiration and we have classified stage III of Durie and Salmon in view of hypercalcemia, anemia, and lytic lesions observed. However, we could not isolate a secretion of monoclonal immunoglobulin in blood but urinary secretion was evident by proteinuria and urinary light chains. The radiographs of our patient found diffuse osteolysis and practice of sternal puncture confirmed multiple myeloma. Our case is original because of rarity on non secretory myeloma particularly with diffuse osteolytic lesion.
文摘Cystic angiomatosis is a rare, benign, multifocal disorder of bone and viscera. Angiomatous deposits result in bone lysis and organ dysfunction. Bony cystic lesions occur in the axial and proximal appendicular skeleton. Lesions may cause bone pain or pathological fracture. Diagnosis is difficult, of exclusion and demands a biopsy. The prognosis varies upon whether the lesions are solely skeletal or there is visceral involvement. A 71-year-old man reports increasing symptoms of painful swelling in the right thoracic wall for over a month. The swelling was bony hard in consistency. Except for his bony swelling, the patient’s physical examination was within normal limits, as were all his laboratory studies. X-ray imagery showed multicystic expansive lytic areas involving the right ribs. Computerized tomography, magnetic resonance imagery and gallium bone scan revealed lytic lesions of multiple right ribs, and cervical, dorsal, lumbar and sacrum iliac spine. A right rib biopsy has shown a cystic formation with endothelial walls. Five years later, the patient remained stable, with no clinical, laboratory or imagilogic progression of disease and without visceral involvement. This case is presented in his rarity and differential diagnosis challenge.
基金supported by National Natural Science Foundation of China(No.31972764)Jiangsu Provincial Key Research and Development Program(No.BE2022361)+1 种基金One belt One road Innovation Cooperation Project of Jiangsu Province(BZ2021009)the Foundation of Coastal Agricultural Science Observation and Experimental Station of Ministry of Agriculture and Rural Affairs(No.YHS202109).
文摘In order to effectively use of phages as antimicrobial agents for controlling multidrug-resistant E.coli,it is important to understand phage biology.The isolation and research of novel bacteriophages are urgently needed for food safety and animal health.Phage is considered as a novel alternative antibacterial agents and a new way of prevent,control and treat pathogens.In this paper,we isolated and characterized a novel lytic phage from chicken samples,named vB_EscP_vE20(in brief vE20).We identified vE20 as belonging to the Podoviridae family through morphological and phylogenetic analysis.It had lytic activities against 24 out of 51 different serotypes of clinical E.coli strains,interestingly it also can lyse Salmonella species,such as Salmonella Enteritidis(S.Enteritidis)and Samonella Typhimu-rium(S.Typhimurium).One step growth curve showed that the latent period and lysis period was 10 min and 60 min,respectively.The burst size of vE20 was about 60 PFU/cell.The phage vE20 survived in a wide range of temperatures(30-60℃)and pH(3-11).The whole genome size of phage vE20 is 77,938 bps,which is double stranded DNA.There are 121 Open reading frame(ORFs)in total,and the GC-content is 42.17%,without virulence-associated,antibiotic and lysogeny related genes.Phage vE20 has high bactericidal activity in killing E.coli EXG20-1 in cultures containing 4×10^(9) cfu/mL in several MOIs culture.The results revealed the promising potential of phage vE20 as attractive candidates for the control of E.coli infections.
基金National Science and Technology Major Project on Important Infectious Diseases Prevention and Control(2018ZX10734404)National Science and Technology Infrastructure of China(National Pathogen Resource Center‐NPRC‐32)+1 种基金National Science and Technology Fundamental Resources Investigation Program of China(2021FY100904)National Nature Science Foundation of China(82161148010‐4,52076140).
文摘Long-term and stable preservation of bacteriophages is of crucial importance.Although many efforts have been made in the past decades to explore the influence of external factors on bacteriophage preservation,there is still little understanding,and a systematic description is lacking.In this study,we explored the influence of different factors on the preservation of lytic bacteriophage VP3,one of the typing bacteriophages of Vibrio cholerae O1 biotype El Tor,and attempted to optimize its preservation.We examined external factors,including temperature,solution,and cryoprotectant,in stable cooling/freezing conditions or alternate cooling/freezing and thawing.We found that whether in Luria-Bertani(LB)medium or SM buffer,in terms of 20-week stable cooling or freezing,−20℃ was the most damaging while 4℃,−80℃,and−196℃ were protective.Thirteen cycles of alternate cooling/freezing and thawing caused a loss in the survival rates of bacteriophages.The addition of cryoprotectant,glycerol(30%,w/v)or dimethyl sulfoxide(DMSO,10%,w/v)significantly improved the survival rates of bacteriophages preserved at−20℃.However,at 4℃,−80℃,and−196℃,the cryoprotectant effect was only slightly positive or even harmful.In summary,for bacteriophage VP3,the best preservation method is to directly preserve the bacteriophage stocks in LB medium at−80℃ or−196℃ instead of storing them in SM buffer or adding cryoprotectant.Our results provided insights into the external influencing factors on bacteriophage VP3 during preservation at low temperature and can be applied to the optimization of bacteriophage preservation in the future.
基金supported by the National Natural Science Foundation of China(31872972,31830076)the Shenzhen Science and Technology Program(KQTD20180411143628272).
文摘Lytic polysaccharide monooxygenases(LPMOs)are important enzymes that boost the hydrolysis of recalcitrant polysaccharides,such as chitin.They are found extensively in different insect species and are classified as auxiliary activities family 15(AA15)LPMOs(LPMO15).Some of them were identified from the insect midgut and proven to act on chitin.However,knowledge about their physiological roles during insect growth and development remains limited.Here,we found that midgut-specific LPMO15s are widely distributed in different insect orders,such as the orthopteran Locusta migratoria and the lepidopteran Bombyx mori.Using L.migratoria as a model insect,the function of midgut-specific LmLPMO15-3 during development was investigated.Double-stranded RNA-mediated downregulation of LmLPMO15-3 expression at the 4th or 5th instar nymph stage severely decreased the survival rate and resulted in lethal phenotypes.Hematoxylin and eosin staining results indicated that the deficient individuals exhibited incompletely digested peritrophic matrix(PM),which suggested that LmLPMO15-3 is essential for the deconstruction of the PM during molting.This study provides direct evidence of the physiological importance of a midgut-specific LPMO15 during insect development.As L.migratoria is one of the most destructive agricultural pests,LmLPMO15-3 is a potential target for pest management.
基金Project supported by the National Natural Science Foundation of China （Nos. 20865002, 20965002）, the Research Funds of Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection （Guangxi Normal University）, Ministry of Education （No. 10012018）.
文摘In pH 3.8 acetic acid-sodium acetate （HAC-NaAC） buffer solution, laccase exhibited a strong catalytic effect on the H2O2 oxidation of I- to form I2, and I2 combined with excess I- to form I3- that reacted with cationic surfactants of tetradecyl dimethylbenzyl ammonium chloride （TDMAC） to produce the （TDMAC-I3）n association complex particles, which exhibited a strong resonance scattering （RS） peak at 468 nm. Under the chosen conditions, as the concentration of laccase activity increased, the RS intensity at 468 nm （1468 nm） increased linearly. The increased RS intensity A1468 nm was linear to laccase activity in the range of 0.08-0.96 U/mL, with a regression equation of △1468 nm =88.8 U-1.9, and a detection limit of 0.02 U/mL laccase. This proposed method was applied to detect laccase activity in waste water, with satisfactory results.
文摘Objectives Systemic lupus erythematosus (SLE) is a multifactorial disease. Environmental factors such as viral infection(s) have been proposed as pathaetiological factors. There are particular interests in studying lymphotropic viruses such as the Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Although previous case reports and in vitro studies suggested that they may have a role, there is no direct evidence that onset of SLE or disease exacerbation is associated with active infection by these viruses. Using the very sensitive polymerase chain reaction (PCR) technique, we tried to find out evidence of active replication of these viruses in patients with SLE. Methods Thirty-four patients with SLE were compared with matched normal controls. Eleven patients were newly diagnosed to have SLE and 18 of the 34 patients had active disease as determined by a SLE Disease Activity Index (SLEDAI) score of ≥10 at the time of study. Results Our results showed no evidence of active replication or reactivation of EBV in the leucocytes amongst the newly diagnosed SLE patients, established SLE patients, patients with SLEDAI ≥10, patients with SLEDAI <10, and control subjects. There was no evidence of CMV infection in any of the subjects studied. The IgG and IgA responses against EBV early antigen (EA) and viral capsid antigen (VCA) were also studied. The IgG and IgA responses against VCA of EBV were increased in patients with SLE when compared with controls. However, there were no differences in these responses among different subgroups of patients. The mechanism of these responses was not apparent but may represent non-specific hyperimmune responses in these patients. There were no differences in the titre of IgG and IgA against EBV EA between the patient groups and controls.Conclusion There is no direct evidence that either EBV or CMV plays a direct role in the onset and/or exacerbation of SLE.
