scholarly journals EndophyticBacillus subtilisStrain E1R-J Is a Promising Biocontrol Agent for Wheat Powdery Mildew

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaoning Gao ◽  
Yufei Gong ◽  
Yunxia Huo ◽  
Qingmei Han ◽  
Zhensheng Kang ◽  
...  
Keyword(s):  
Cell Suspension ◽  
Bacterial Cell ◽  
Crude Protein ◽  
Disease Index ◽  
Conidial Germination ◽  
Bacterial Strains ◽  
Fermentation Liquid ◽  
Bacterial Cell Suspension ◽  
Wheat Leaves ◽  
Germ Tubes

In this study, the biocontrol efficacies of 14 endophytic bacterial strains were tested againstBlumeria graminisf. sp.tritici(Bgt) in pot experiments under greenhouse conditions.Bacillus subtilisstrain E1R-j significantly reduced disease index and exhibited the best control (90.97%). When different formulations of E1R-j were sprayed 24 h beforeBgtinoculation, fermentation liquid without bacterial cell and crude protein suspension displayed the similar effects; and they reduced disease index more than bacterial cell suspension (109 cfu mL−1) and fermentation liquid without protein. The control effects were not significantly different between 1011and 109 cfu mL−1of bacterial cell suspension but were higher than 107 cfu mL−1. Further observations showed that conidial germination and appressorial formation ofBgtwere retarded by spraying E1R-j 24 h beforeBgtinoculation. Compared with the water check, conidial germination and appressorial formation were decreased by 43.3% and 42.7%, respectively. In the treatment with E1R-j, the number of houstoria significantly reduced and the speed of mycelial extension was slowed down in the wheat leaves. Scanning electron microscopy observation revealed that E1R-j significantly suppressed the conidial germination and caused rupture and deformation of germ tubes. On the surface of wheat leaves, mycelia and conidiophores became shrinking.

Factors Affecting the Persistence of Salmonella During the Processing of Poultry

1989 ◽  
Vol 52 (11) ◽  
pp. 829-832 ◽  
Author(s):  
H. S. LILLARD
Keyword(s):  
Electron Microscopy ◽  
Cell Suspension ◽  
Significant Role ◽  
Bacterial Cell ◽  
Water Immersion ◽  
False Negative ◽  
Water Film ◽  
Bacterial Cells ◽  
Factors Affecting ◽  
Bacterial Cell Suspension

Bacteria, including Salmonella, have been shown to attach firmly to poultry skin and meat. Neither fimbriae, flagella, nor electrostatic attraction seem to play a significant role in the mechanism of attachment. Bacterial cells (95%) were shown to be initially entrapped in a water film on the skin, then to migrate to the skin with prolonged immersion in a bacterial cell suspension. Using electron microscopy it was shown that bacteria appear to be entrapped in ridges and crevices which become more pronounced in the skin and muscle following water immersion. This may make bacteria on carcasses inaccessible to bactericides. It was shown that bacteria are firmly attached to poultry skin before broilers arrive at the plant and that high numbers are still recovered after 40 consecutive whole carcass rinses of a single carcass. It was further shown that Salmonella are not always recovered in the first whole carcass rinse and that this method of sampling could result in false negative reports for Salmonella incidence.

scholarly journals Evaluation of non-thermal effect of microwave radiation and its mode of action in bacterial cell inactivation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Priyanka Shaw ◽  
Naresh Kumar ◽  
Sohail Mumtaz ◽  
Jun Sup Lim ◽  
Jung Hyun Jang ◽  
...  
Keyword(s):  
Thermal Effect ◽  
Microwave Radiation ◽  
Bacterial Cell ◽  
Mode Of Action ◽  
Surface Damage ◽  
Peak Frequency ◽  
Viable Count ◽  
Bacterial Inactivation ◽  
Bacterial Strains ◽  
Log Reduction

AbstractA growing body of literature has recognized the non-thermal effect of pulsed microwave radiation (PMR) on bacterial systems. However, its mode of action in deactivating bacteria has not yet been extensively investigated. Nevertheless, it is highly important to advance the applications of PMR from simple to complex biological systems. In this study, we first optimized the conditions of the PMR device and we assessed the results by simulations, using ANSYS HFSS (High Frequency Structure Simulator) and a 3D particle-in-cell code for the electron behavior, to provide a better overview of the bacterial cell exposure to microwave radiation. To determine the sensitivity of PMR, Escherichia coli and Staphylococcus aureus cultures were exposed to PMR (pulse duration: 60 ns, peak frequency: 3.5 GHz) with power density of 17 kW/cm2 at the free space of sample position, which would induce electric field of 8.0 kV/cm inside the PBS solution of falcon tube in this experiment at 25 °C. At various discharges (D) of microwaves, the colony forming unit curves were analyzed. The highest ratios of viable count reductions were observed when the doses were increased from 20D to 80D, which resulted in an approximate 6 log reduction in E. coli and 4 log reduction in S. aureus. Moreover, scanning electron microscopy also revealed surface damage in both bacterial strains after PMR exposure. The bacterial inactivation was attributed to the deactivation of oxidation-regulating genes and DNA damage.

scholarly journals Evaluating the abilities of diverse nitroaromatic prodrug metabolites to exit a model Gram negative vector for bacterial-directed enzyme-prodrug therapy

2020 ◽  
Author(s):  
JVE Chan-Hyams ◽  
JN Copp ◽  
JB Smaill ◽  
AV Patterson ◽  
David Ackerley
Keyword(s):  
Human Cell ◽  
Bacterial Cell ◽  
Bystander Effect ◽  
Cell Transfer ◽  
Bacterial Strains ◽  
Enzyme Prodrug Therapy ◽  
E Coli ◽  
Human Cell Cultures ◽  
Cell To Cell Transfer ◽  
Nitro Reduction

© 2018 Elsevier Inc. Gene-directed enzyme-prodrug therapy (GDEPT) employs tumour-tropic vectors including viruses and bacteria to deliver a genetically-encoded prodrug-converting enzyme to the tumour environment, thereby sensitising the tumour to the prodrug. Nitroreductases, able to activate a range of promising nitroaromatic prodrugs to genotoxic metabolites, are of great interest for GDEPT. The bystander effect (cell-to-cell transfer of activated prodrug metabolites) has been quantified for some nitroaromatic prodrugs in mixed multilayer human cell cultures, however while these provide a good model for viral DEPT (VDEPT) they do not inform on the ability of these prodrug metabolites to exit bacterial vectors (relevant to bacterial-DEPT (BDEPT)). To investigate this we grew two Escherichia coli strains in co-culture; an activator strain expressing the nitroreductase E. coli NfsA and a recipient strain containing an SOS-GFP DNA damage responsive gene construct. In this system, induction of GFP by reduced prodrug metabolites can only occur following their transfer from the activator to the recipient cells. We used this to investigate five clinically relevant prodrugs: metronidazole, CB1954, nitro-CBI-DEI, and two dinitrobenzamide mustard prodrug analogues, PR-104A and SN27686. Consistent with the bystander efficiencies previously measured in human cell multilayers, reduced metronidazole exhibited little bacterial cell-to-cell transfer, whereas nitro-CBI-DEI was passed very efficiently from activator to recipient cells post-reduction. However, in contrast with observations in human cell multilayers, the nitrogen mustard prodrug metabolites were not effectively passed between the two bacterial strains, whereas reduced CB1954 was transferred efficiently. Using nitroreductase enzymes that exhibit different biases for the 2- versus 4-nitro substituents of CB1954, we further showed that the 2-nitro reduction products exhibit substantially higher levels of bacterial cell-to-cell transfer than the 4-nitro reduction products, consistent with their relative bystander efficiencies in human cell culture. Overall, our data suggest that prodrugs may differ in their suitability for VDEPT versus BDEPT applications and emphasise the importance of evaluating an enzyme-prodrug partnership in an appropriate context for the intended vector.

scholarly journals The key bacterial cell division protein FtsZ as a novel antibacterial drug target

2020 ◽  
Author(s):  
Mujeeb Rahman ◽  
Ping Wang ◽  
Na Wang ◽  
Yaodong Chen
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Drug Targets ◽  
Multidrug Resistant ◽  
Antibacterial Drug ◽  
Bacterial Cell Division ◽  
Bacterial Strains ◽  
Antimicrobial Drugs ◽  
Novel Antibiotics

The number of multidrug-resistant bacterial strains is currently increasing; thus, the determination of drug targets for the development of novel antimicrobial drugs is urgently needed. FtsZ, the prokaryotic homolog of the eukaryotic tubulin, is a GTP-dependent prokaryotic cytoskeletal protein that is conserved among most bacterial strains. In vitro studies revealed that FtsZ self-assembles into dynamic protofilaments or bundles, and it forms a dynamic Z-ring at the center of the cell, leading to septation and consequent cell division. The potential role of FtsZ in the blockage of cell division makes FtsZ a highly attractive target for developing novel antibiotics. Researchers have been working on synthetic molecules and natural products as inhibitors of FtsZ. Accumulating data suggest that FtsZ may provide the platform for the development of novel antibiotics. In this review, we summarize recent advances on the properties of FtsZ protein and bacterial cell division, as well as on the development of FtsZ inhibitors.

scholarly journals Effects of natural antimicrobials on bacterial cell hydrophobicity, adhesion, and zeta potential / Vpliv naravnih protimikrobnih snovi na bakterijsko hidrofobnost, adhezijo in zeta potencial

2016 ◽  
Vol 67 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Marija Kurinčič ◽  
Barbara Jeršek ◽  
Anja Klančnik ◽  
Sonja Smole Možina ◽  
Rok Fink ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Bacterial Adhesion ◽  
Bacterial Cell ◽  
Early Stage ◽  
Experimental Studies ◽  
Adhesion Prevention ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Natural Antimicrobials ◽  
Cell Hydrophobicity

Abstract Interactions between bacterial cells and contact materials play an important role in food safety and technology. As bacterial strains become ever more resistant to antibiotics, the aim of this study was to analyse adhesion of selected foodborne bacterial strains on polystyrene surface and to evaluate the effects of natural antimicrobials on bacterial cell hydrophobicity, adhesion, and zeta potential as strategies of adhesion prevention. The results showed strain-specific adhesion rate on polystyrene. The lowest and the highest adhesion were found for two B. cereus lines. Natural antimicrobials ferulic and rosmarinic acid substantially decreased adhesion, whereas the effect of epigallocatechin gallate was neglectful. Similar results were found for the zeta potential, indicating that natural antimicrobials reduce bacterial adhesion. Targeting bacterial adhesion using natural extracts we can eliminate potential infection at an early stage. Future experimental studies should focus on situations that are as close to industrial conditions as possible.

Increased Lipoxygenase Activity is Involved in the Hypersensitive Response of Wheat Leaf Cells Infected with A virulent Rust Fungi or Treated with Fungal Elicitor

1986 ◽  
Vol 41 (5-6) ◽  
pp. 559-563 ◽  
Author(s):  
Carlos A. Ocampo ◽  
Bruno Moerschbacher ◽  
Hans J. Grambow
Keyword(s):  
Hypersensitive Response ◽  
Hypersensitive Reaction ◽  
Rust Fungi ◽  
Lipoxygenase Activity ◽  
Puccinia Graminis ◽  
Compatible Interaction ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Germ Tubes ◽  
Wheat Rust

The hypersensitive reaction in incompatible wheat-rust interactions is characterized by an increase in lipoxygenase activity detectable as early as 28 h after penetration of the pathogen. In contrast, lipoxygenase activity in the compatible interaction did not increase until the onset of sporulation.Lipoxygenase activity also increased following treatment of wheat leaves with an elicitor fraction from germ tubes of Puccinia graminis tritici.

Antibacterial Activities of Antibacterial Proteins/Peptides Isolated from Organs and Mucus of Clarias Gariepinus Reared at High Stocking Density

2012 ◽  
Vol 455-456 ◽  
pp. 455-460 ◽  
Author(s):  
Xiao Mei Wang ◽  
Wei Dai ◽  
Ke Zhing Xing ◽  
Tian Jun Li ◽  
Xin Wang
Keyword(s):  
Molecular Weight ◽  
Antibacterial Activity ◽  
Crude Protein ◽  
Clarias Gariepinus ◽  
Gel Filtration ◽  
Stocking Density ◽  
Antibacterial Activities ◽  
Edwardsiella Tarda ◽  
Bacterial Strains ◽  
Sds Page

. Antibacterial proteins/peptides are important parts of the innate immune system in Clarias gariepinus. To examine potential antibacterial proteins/peptides in organs and mucus of C. gariepinus, crude protein/peptide extracts were isolated with ammonium sulfate precipitation from mucus, skin, gill, suprabranchial organ and intestine. Following further extraction using Sephadex G-50 gel filtration chromatography, the proteins/peptides associated with two absorption peaks (AP1 and AP2) were pooled, respectively, and assayed for their antibacterial activities against Escherichia coli, Aeromonas hydrophila and Edwardsiella tarda. The results showed that AP1 and AP2 from all the sampled tissues and mucus at concentration of 100 mg mL-1 exhibited antibacterial activity against the tested bacterial strains. Differences in antibacterial activity were observed among sample extracts. The protein profiles of AP1 obtained by Tricine-SDS-PAGE gel showed a broad range of peptides/proteins, and molecular weight of the mutual abundant peptide obtained was about 27 kDa. Antibacterial activity of AP2 extracted from intestine was due to peptide with molecular weight of 5.5 kDa.

scholarly journals Combating the melioidosis pathogen using antibiotics in combination with silver nanoparticles

2020 ◽  
Author(s):  
Sathit Malawong ◽  
Saengrawee Thammawithan ◽  
Pawinee Sirithongsuk ◽  
Sawinee Nasompag ◽  
Sakda Daduang ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Cell ◽  
Inhibitory Concentration ◽  
Morphological Changes ◽  
Cell Structure ◽  
Cellular Damage ◽  
Bacterial Strains ◽  
Bacterial Cell Death ◽  
Bactericidal Effects ◽  
Conventional Antibiotics

Abstract Background Melioidosis is an infectious disease caused by the Gram-negative bacillus bacterium, Burkholderia pseudomallei. Due to the emerging resistance of B. pseudomallei to antibiotics, including ceftazidime (CAZ), the development of novel antibiotics and alternative modes of treatment has become an urgent issue. Here, we demonstrate an ability to synergistically increase the efficiency of antibiotics through their combination with silver nanoparticles (AgNPs). Method: Combinations of four conventional antibiotics, including CAZ, imipenem (IMI), meropenem (MER), or gentamicin sulfate (GENT), with AgNPs were tested for their bactericidal effects against three isolates of B. pseudomallei, including 1026b, H777, and 316c, using the microdilution checkerboard method of antibiotic and AgNPs mixing. Morphological changes in the bacteria after treatment with the combined antibiotic-AgNPs was observed using scanning electron microscopy (SEM). Result The combination of four antibiotics with AgNPs gave fractional inhibitory concentration (FIC) index values and fractional bactericidal concentration (FBC) index values ranging from 0.312 to 0.75 µg/mL and 0.252 to 0.625 µg/mL, respectively, against the three isolates of B. pseudomallei. SEM imaging revealed damage to the bacterial cell structure at the minimal inhibitory concentration (MIC) and FIC levels, while extreme severe cellular damage was observed at the FBC level. Surprisingly, at the FBC level, the bacteria produced large amounts of fibers that are the components of biofilm. Conclusion The study clearly shows that most of the combinatorial treatments exhibited synergistic antimicrobial effects against all three isolates of B. pseudomallei. The highest enhancing effect was observed for GENT with AgNPs. We also found that the combination of these antibiotics with AgNPs restored their bactericidal potency in the bacterial strains previously shown to be resistant to the antibiotic. The observed synergistic activities of conventional antibiotics with AgNPs suggest that it might also be possible to achieve equivalent or higher levels of bacterial cell death with lower concentrations of antibiotics using the combined treatments. These results support the use of the antibiotic/AgNPs combination as an alternative design strategy for new therapeutics to more effectively combat melioidosis.

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