scholarly journals Killer Activity of Hanseniaspora uvarum Isolated from Dates Vinegar: Partially Purification and Characterization of Killer Toxin

2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0140
Author(s):  
Hameed Et al.
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Killer Toxin ◽  
Toxin Production ◽  
Antagonistic Activity ◽  
Killer Activity ◽  
E Coli ◽  
Killer Yeast ◽  
Hanseniaspora Uvarum

This study was conducted to isolate and identify killer yeast Hanseniaspora uvarum from dates vinegar and measurement the ability of this yeast to produce killer toxin. The antimicrobial activity of the concentrated supernatant containing partially purified concentrated killer toxin was also detected against several pathogenic bacteria and yeast species, which includes two types of yeast Rhodotorula mucilaginosa and Candida tropicalis and four human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeurginosa. In addition, the antagonistic activity of examined yeast have been studied toward four types of fungi, where two are pathogenic for human Trichophyton mentagrophytes and Trichophyton rubrum and two are plant pathogens Fusarium solani and Sclerotinia sclerotiorum. The results of killer toxin production experiments revealed the ability of yeast to produce killer toxin with molecular weight at 18 kDa by 12 % SDS electrophoresis. The optimal conditions for killer toxin production were studied, and their antimicrobial activity was determined. The results revealed that killer toxin production was increased at 4 % NaCl, the highest inhibtion zone was 20 mm for S. aureus, while the lowest inhibition zone was 7 mm for E. coli. Killer activity was increased at pH 4 and the best inhibtion zone obtained was about 16 mm for K. pneumoniae, while 8 mm for E. coli and C. tropicalis. The temperature was also affect the production of killer toxin, where 25 °C is the best temperature for toxin production of examined yeast, The best killer activity was 21 mm for C. tropicalis. The antagonistic activity of killer yeast H. uvarum toward pathogenic fungal growth was determined and showed killer activity about 61.11, 44.44, 33.33 and 24.44 % against T. mentagrophytes, T.  rubrum, F. solani and S. sclerotiorum in comparison to the control.

scholarly journals Killer Activity of Hanseniaspora uvarum Isolated from Dates Vinegar: Partially Purification and Characterization of Killer Toxin

2019 ◽  
Vol 16 (1) ◽  
pp. 0140
Author(s):  
Hameed Et al.
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Killer Toxin ◽  
Toxin Production ◽  
Antagonistic Activity ◽  
Killer Activity ◽  
E Coli ◽  
Killer Yeast ◽  
Hanseniaspora Uvarum

This study was conducted to isolate and identify killer yeast Hanseniaspora uvarum from dates vinegar and measurement the ability of this yeast to produce killer toxin. The antimicrobial activity of the concentrated supernatant containing partially purified concentrated killer toxin was also detected against several pathogenic bacteria and yeast species, which includes two types of yeast Rhodotorula mucilaginosa and Candida tropicalis and four human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeurginosa. In addition, the antagonistic activity of examined yeast have been studied toward four types of fungi, where two are pathogenic for human Trichophyton mentagrophytes and Trichophyton rubrum and two are plant pathogens Fusarium solani and Sclerotinia sclerotiorum. The results of killer toxin production experiments revealed the ability of yeast to produce killer toxin with molecular weight at 18 kDa by 12 % SDS electrophoresis. The optimal conditions for killer toxin production were studied, and their antimicrobial activity was determined. The results revealed that killer toxin production was increased at 4 % NaCl, the highest inhibtion zone was 20 mm for S. aureus, while the lowest inhibition zone was 7 mm for E. coli. Killer activity was increased at pH 4 and the best inhibtion zone obtained was about 16 mm for K. pneumoniae, while 8 mm for E. coli and C. tropicalis. The temperature was also affect the production of killer toxin, where 25 °C is the best temperature for toxin production of examined yeast, The best killer activity was 21 mm for C. tropicalis. The antagonistic activity of killer yeast H. uvarum toward pathogenic fungal growth was determined and showed killer activity about 61.11, 44.44, 33.33 and 24.44 % against T. mentagrophytes, T.  rubrum, F. solani and S. sclerotiorum in comparison to the control.

The ecological role of killer yeasts in natural communities of yeasts

1987 ◽  
Vol 33 (9) ◽  
pp. 783-796 ◽  
Author(s):  
William T. Starmer ◽  
Philip F. Ganter ◽  
Virginia Aberdeen ◽  
Marc-Andre Lachance ◽  
Herman J. Phaff
Keyword(s):  
Yeast Species ◽  
Kluyveromyces Lactis ◽  
Killer Toxin ◽  
Toxin Production ◽  
Killer Activity ◽  
Killer Yeast ◽  
Killer Toxins ◽  
Naturally Occurring ◽  
Pichia Kluyveri

The killer phenomenon of yeasts was investigated in naturally occurring yeast communities. Yeast species from communities associated with the decaying stems and fruits of cactus and the slime fluxes of trees were studied for production of killer toxins and sensitivity to killer toxins produced by other yeasts. Yeasts found in decaying fruits showed the highest incidence of killing activity (30/112), while yeasts isolated from cactus necroses and tree fluxes showed lower activity (70/699 and 11/140, respectively). Cross-reaction studies indicated that few killer-sensitive interactions occur within the same habitat at a particular time and locality, but that killer-sensitive reactions occur more frequently among yeasts from different localities and habitats. The conditions that should be optimal for killer activity were found in fruits and young rots of Opuntia cladodes where the pH is low. The fruit habitat appears to favor the establishment of killer species. Killer toxin may affect the natural distribution of the killer yeast Pichia kluyveri and the sensitive yeast Cryptococcus cereanus. Their distributions indicate that the toxin produced by P. kluyveri limits the occurrence of Cr. cereanus in fruit and Opuntia pads. In general most communities have only one killer species. Sensitive strains are more widespread than killer strains and few species appear to be immune to all toxins. Genetic study of the killer yeast P. kluyveri indicates that the mode of inheritance of killer toxin production is nuclear and not cytoplasmic as is found in Saccharomyces cerevisiae and Kluyveromyces lactis.

scholarly journals Killer toxin of Saccharomyces cerevisiae Y500-4L active against Fleischmann and Itaiquara commercial brands of yeast

1999 ◽  
Vol 30 (3) ◽  
pp. 253-257 ◽  
Author(s):  
Giselle A.M. Soares ◽  
Hélia H. Sato
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Elevated Temperatures ◽  
Killer Toxin ◽  
Toxin Production ◽  
Chromosomal Dna ◽  
Killer Activity ◽  
Killer Yeast ◽  
Torulopsis Glabrata ◽  
Hansenula Anomala ◽  
Killer Yeasts

The strain Saccharomyces cerevisiae Y500-4L, previously selected from the must of alcohol producing plants and showing high fermentative and killer capacities, was characterized according to the interactions between the yeasts and examined for curing and detection of dsRNA plasmids, which code for the killer character. The killer yeast S. cerevisiae Y500-4L showed considerable killer activity against the Fleischmann and Itaiquara commercial brands of yeast and also against the standard killer yeasts K2 (S. diastaticus NCYC 713), K4 (Candida glabrata NCYC 388) and K11 (Torulopsis glabrata ATCC 15126). However S. cerevisiae Y500-4L showed sensitivity to the killer toxin produced by the standard killer yeasts K8 (Hansenula anomala NCYC 435), K9 (Hansenula mrakii NCYC 500), K10 (Kluyveromyces drosophilarum NCYC 575) and K11 (Torulopsis glabrata ATCC 15126). No M-dsRNA plasmid was detected in the S. cerevisiae Y500-4L strain and these results suggest that the genetic basis for toxin production is encoded by chromosomal DNA. The strain S. cerevisiae Y500-4L was more resistant to the loss of the phenotype killer with cycloheximide and incubation at elevated temperatures (40oC) than the standard killer yeast S. cerevisiae K1.

Killer toxin of Pichia membranifaciens and its possible use as a biocontrol agent against grey mould disease of grapevine

Microbiology ◽  
2004 ◽  
Vol 150 (8) ◽  
pp. 2527-2534 ◽  
Author(s):  
A. Santos ◽  
D. Marquina
Keyword(s):  
Killer Toxin ◽  
Grey Mould ◽  
Toxin Production ◽  
Killer Activity ◽  
Pichia Membranifaciens ◽  
Sds Page ◽  
Toxin Protein ◽  
Killing Action ◽  
Killer Protein ◽  
Potential Use

The use of Pichia membranifaciens CYC 1106 killer toxin against Botrytis cinerea was investigated. This strain exerted a broad-specificity killing action against other yeasts and fungi. At pH 4, optimal killer activity was observed at temperatures up to 20 °C. At 25 °C the toxic effect was reduced to 70 %. The killer activity was higher in acidic medium. Above about pH 4·5 activity decreased sharply and was barely noticeable at pH 6. The killer toxin protein from P. membranifaciens CYC 1106 was purified to electrophoretic homogeneity. SDS-PAGE of the purified killer protein indicated an apparent molecular mass of 18 kDa. Killer toxin production was stimulated in the presence of non-ionic detergents. The toxin concentrations present in the supernatant during optimal production conditions exerted a fungicidal effect on a strain of B. cinerea. The symptoms of infection and grey mould observed in Vitis vinifera plants treated with B. cinerea were prevented in the presence of purified P. membranifaciens killer toxin. The results obtained suggest that P. membranifaciens CYC 1106 killer toxin is of potential use in the biocontrol of B. cinerea.

scholarly journals The Assessment of antimicrobial activity of cerumen (earwax) and antibiotics against pathogenic bacteria isolated from ear pus samples

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Iffat Naz
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Maximum Activity ◽  
Prevalence Data ◽  
Culture Techniques ◽  
E Coli ◽  
Pseudomonas Spp ◽  
Test Organisms ◽  
Staphylococcus Spp

The present study is focused on the assessment of the antimicrobial activity of cerumen and antibiotics against bacteria isolated from ear pus samples. Thus, a total of 50 ear pus samples were collected from infected patients using sterile swabs and were screened using pure culture techniques. Total of 04 different bacterial isolates were identified while, the prevalence data revealed that Pseudomonas spp., were dominant (58%, n = 29) among isolated bacteria followed by Staphylococcus spp., (22%, n = 11), Escherichia coli (14%, n = 7) and Proteus spp., (6%, n = 3). Further, bioassay revealed that Pseudomonas spp., and Staphylococcus spp., were most sensitive to Clindamycin (94.73%) while displayed resistant to Ciprofloxacin and Ampicillin. Similarly, E. coli and Proteus spp., were most sensitive to Ciprofloxacin (92.8-95.21%) as compared to the other antibiotics. Moreover, antibacterial activity of cerumen was also assessed against test organisms and its maximum activity was observed against Pseudomonas spp., (90% equivalent to Clindamycin potency) and Staphylococcus spp., (60% equivalent to Amoxicillin potency) while least effective against E. coli (36%) and Proteus spp., (22%). Thus, it was concluded that the antibacterial activity of cerumen might be due to the presence of potential chemicals i.e. flavonoids and terpenoids.

scholarly journals Antimicrobial effects of fruit sauces on some pathogenic bacteria in vitro and on chicken breast meat

2021 ◽  
Vol 72 (1) ◽  
pp. 2703
Author(s):  
I VAR ◽  
S UZUNLU ◽  
I DEĞIRMENCI
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Diffusion Method ◽  
Chicken Breast ◽  
Type I ◽  
Antimicrobial Effects ◽  
E Coli ◽  
Agar Diffusion

The use of natural food additives is currently a rising trend. In the present study, the aim was to determine the antimicrobial effects of plum, pomegranate, Seville orange and sumac sauces on E. coli O157:H7,E. coli type I,Listeriamonocytogenes, Listeria ivanovii, Salmonella Typhimurium and Staphylococcus aureus. Different concentrations (1%, 10%, 100%, v/v) of the sauces were tested on the studied bacteria in vitro using the agar diffusion and minimal inhibition concentration (MIC) methods. The results showed that the sumac sauce had the highest antimicrobial activity. The Seville orange, plum and pomegranate sauces also exerted antimicrobial activity in descending order. The antimicrobial activity of the fruit sauces was more effective at a concentration of 100% than at 10% and 1%, v/v. The most inhibitory effect was recorded for sumac sauce at a concentration of 100% (v/v) on L.monocytogenesand E. coli O157:H7. The findings of the MIC method aligned with the agar diffusion method. In addition, the in situ(food method) antimicrobial effect of the sauces on the indigenous microflora of chicken breast samples sold in stores was determined. Chicken samples hosting aerobic mesophilic bacteria, coliforms and E. coli were treated for two hours at 4 °C with plum, pomegranate, Seville orange and sumac sauces and were then monitored. The findings revealed that the Seville orange and sumac sauces were the most effective in reducing the indigenous microbial growth on the chicken samples. The plum sauce showed higher antimicrobial activity than pomegranate sauce. The phenolic content and acidity of the samples significantly (P< 0.05) affected the antimicrobial activity both in vitro (agar diffusion and MIC) and in situ (chilled chicken breast). In conclusion, the sumac and Seville orange sauces were found to be the most promising natural antibacterial agents, and their use could be recommended, for example, in catering services to reduce the risk of foodborne illness.

scholarly journals Survey of Toxin–Antitoxin Systems in Erwinia amylovora Reveals Insights into Diversity and Functional Specificity

Toxins ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 206
Author(s):  
Teja Shidore ◽  
Quan Zeng ◽  
Lindsay Triplett
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Erwinia Amylovora ◽  
Plasmid Stability ◽  
Hidden Markov ◽  
Cytoskeletal Proteins ◽  
Type Ii ◽  
Functional Specificity ◽  
E Coli

Toxin–antitoxin (TA) systems are diverse genetic modules with demonstrated roles in plasmid stability, stress management, biofilm formation and antibiotic persistence. However, relatively little is known about their functional significance in plant pathogens. In this study we characterize type II and IV TA systems in the economically important plant pathogen Erwinia amylovora. Hidden Markov Model (HMM) and BLAST-based programs were used to predict the identity and distribution of putative TA systems among sequenced genomes of E. amylovora and other plant-associated Erwinia spp. Of six conserved TA systems tested for function from E. amylovora, three (CbtA/CbeA, ParE/RHH and Doc/PhD) were validated as functional. CbtA was toxic to E. amylovora, but not to Escherichia coli. While the E. coli homolog of CbtA elicits the formation of lemon-shaped cells upon overexpression and targets cytoskeletal proteins FtsZ and MreB, E. amylovora CbtA led to cell elongation and did not interact with these cytoskeletal proteins. Phylogenetic analysis revealed that E. amylovora CbtA belongs to a distinct clade from the CbtA of pathogenic E. coli. This study expands the repertoire of experimentally validated TA systems in plant pathogenic bacteria, and suggests that the E. amylovora homolog of CbtA is functionally distinct from that of E. coli.

Antimicrobial activity of Commercial essential oils on human pathogens

2021 ◽  
pp. 4440-4444
Author(s):  
B. R. Malathy ◽  
Sweetlin Ajitha P ◽  
Sangeetha K. S ◽  
Swetha Thampy ◽  
Kamala G
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Steam Distillation ◽  
Diffusion Method ◽  
Human Pathogens ◽  
Aromatic Plants ◽  
Zone Of Inhibition ◽  
E Coli ◽  
Development Of Resistance

Essential oils (EOs) are natural extracts from the seeds, stems, roots, flowers, bark and other parts of the plant prepared by steam distillation. They are complex, volatile, natural compounds formed by aromatic plants as secondary metabolites. They are known for their bactericidal, virucidal, fungicidal, sedative, anti-inflammatory, analgesic, spasmolytic and locally anesthetic properties. They are generally composed of a combination of substances like terpenes, phenolics, aldehydes or alcohols. The complex composition and different mechanisms of action of EOs may be an advantage over other antimicrobials to prevent the development of resistance of pathogenic bacteria. With this background, the aim of this study was to evaluate the antimicrobial activity of five essential oils like basil, lime, rosemary, thyme and canada balsam against 14 microbes. The effects of essential oil on the selected microbes were determined by agar well diffusion method. The zone of inhibition was observed and measured in millimeter. Essential oils which showed inhibitory diameter >15 mm were further tested to determine the minimum inhibitory concentration (MIC). S. aureus, E. coli, S. mutans, S. sanguinis, C. albicans and M. furfur were inhibited by all essential oils. K. pneumoniae, P. aeruginosa and E .faecalis were inhibited only by thyme and not by other essential oils. The MIC values ranged from 50% to 0.10%. The least MIC value of 0.10% was shown by thyme and basil to S. aureus, thyme to E.coli and all essential oils against C. albicans except lime.

scholarly journals Production, Characterization, and Antimicrobial Activity of Mycocin Produced byDebaryomyces hanseniiDSMZ70238

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Safaa A. S. Al-Qaysi ◽  
Halah Al-Haideri ◽  
Zaid Akram Thabit ◽  
Wijdan Hameed Abd Al-Razzaq Al-Kubaisy ◽  
Jamal Abd Al-Rahman Ibrahim
Keyword(s):  
Antimicrobial Activity ◽  
Trichophyton Rubrum ◽  
Killer Toxin ◽  
Pathogenic Fungi ◽  
Inhibition Zone ◽  
Toxin Production ◽  
Inhibitory Effect ◽  
Curvularia Lunata ◽  
Nacl Concentration ◽  
Inhibition Zones

The present study was conducted to estimate the antimicrobial activity and the potential biological control of the killer toxin produced byD. hanseniiDSMZ70238 against several pathogenic microorganisms. In this study, the effects of NaCl, pH, and temperature, killer toxin production, and antimicrobial activity were studied. The results showed that the optimum inhibitory effect of killer toxin was at 8% NaCl, and the diameters of clear zones were 20, 22, 22, 21, 14, and 13 mm forStaphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes, Candida albicans,andCandida neoformans, respectively. The largest inhibition zones were observed at pH 4.5 with inhibition zone of 16, 18, 17, 18, 11, and 12 mm for the same microorganisms. The results also showed that 25°C is the optimal temperature for toxin killing activity against all targeted microorganisms. In addition, the activity of killer toxin significantly inhibited the growth of fungal mycelia for all target pathogenic fungi and the percentages of inhibition were 47.77, 48.88, 52.22, and 61.11% forTrichophyton rubrum, Alternaria alternata, Trichophyton concentricum,andCurvularia lunata, respectively. The results showed the highest growth rate ofD. hanseniiDSMZ70238 under condition of 8% NaCl concentration, pH 4.5, and 25°C for 72 h.

scholarly journals Phenotypic and Genotypic Characteristics of Enterocin Producing Enterococci against Pathogenic Bacteria

2015 ◽  
Vol 38 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Sandra Mojsova ◽  
Kiril Krstevski ◽  
Igor Dzadzovski ◽  
Zagorka Popova ◽  
Pavle Sekulovski
Keyword(s):  
Antimicrobial Activity ◽  
Pathogenic Bacteria ◽  
Structural Genes ◽  
E Coli ◽  
Technological Potential ◽  
Cheese Industry ◽  
Pcr Method ◽  
Enterocin A ◽  
Genotypic Characteristics ◽  
Enterocin P

AbstractThe study investigated the antimicrobial activity of 13 enterococcal strains (E. faecalis -8, E. faecium-2, E. hirae-2, E. spp.-1) isolated from our traditional cheeses against pathogen microorganisms. Also, it includes the detection of the following enterocin structural genes: enterocin A, enterocin B, enterocin P, enterocin L50A/B, bacteriocin 31, enterocin AS48, enterocin Q, enterocin EJ97 and cytolysin by using PCR method. All isolates inhibited growth of L. monocytogenes and L.innocua. One isolate had a broader antimicrobial activity. None of the isolates showed inhibitory activity against S. enteritidis, E. coli and Y. enterocolitica. The genes enterocin P, cytolysin and enterocin A were the most frequently detected structural genes among the PCR positive strains. No amplification was obtained in two strains E. faecalis-25 and E. faecalis-86. Three different genes were identified in some strains. With the exclusion of strains possessing a virulence factor, such as cytolysin, producers of more than one enterocins could be of a great technological potential as protective cultures in the cheese industry.

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