Keratinolytic potential ofBacillus licheniformisRG1: structural and biochemical mechanism of feather degradation

2005 ◽  
Vol 51 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Priya Ramnani ◽  
Rajni Singh ◽  
Rani Gupta
Keyword(s):  
Bacillus Licheniformis ◽  
Bacterial Adhesion ◽  
Degradation Process ◽  
Bacterial Cells ◽  
Disulfide Bridges ◽  
Feather Degradation ◽  
Keratinolytic Activity ◽  
Disulfide Reductase ◽  
Live Bacterial Cells ◽  
Disulfide Reductases

Keratinolytic Bacillus licheniformis RG1 was used to study the mechanism of keratinolysis. Scanning electron microscopy studies revealed that bacterial cells grew closely adhered to the barbules of feathers, completely degrading them within 24 h. Biochemical studies indicated that the Bacillus strain produced an extracellular protease, which had keratinolytic potential. The extracellular keratinolytic activity (425 U) was synergistically enhanced by the addition of intracellular disulfide reductases (1712 U). However, these enzymes alone (keratinase and disulfide reductase), without live bacterial cells, failed to degrade the feather. Complete feather degradation was obtained only when living bacterial cells were present, emphasizing that bacterial adhesion plays a key role during the degradation process. The bacterial cells probably provide a continuous supply of reductant to break disulfide bridges. In addition, sulfite detected in the extracellular broth during feather degradation indicated that sulfitolysis may also play a role in feather degradation by the bacterium.Key words: Bacillus licheniformis, disulfide reductase, keratinase, sulfitolysis.

Real-time monitoring and inhibition of the activity of carbapenemase in live bacterial cells: application to screening of β-lactamase inhibitors

2020 ◽  
Vol 44 (46) ◽  
pp. 20334-20340
Author(s):  
Han Gao ◽  
Ying Ge ◽  
Min-Hao Jiang ◽  
Cheng Chen ◽  
Le-Yun Sun ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Real Time ◽  
Bacterial Cells ◽  
Real Time Monitoring ◽  
Live Bacterial Cells

Antibiotic resistance mediated by β-lactamases including metallo-β-lactamases (MβLs) has become an emerging threat.

scholarly journals A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial Adhesion and Biofilm Formation

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2771
Author(s):  
Tobias Wieland ◽  
Julia Assmann ◽  
Astrid Bethe ◽  
Christian Fidelak ◽  
Helena Gmoser ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Real Time ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Bovine Mastitis ◽  
Inhibitory Effect ◽  
Thermal Sensor ◽  
Bacterial Cells ◽  
Static Conditions

The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.

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.

scholarly journals Effect of milk chocolate supplementation with lyophilised Lactobacillus cells on its attributes

2010 ◽  
Vol 28 (No. 5) ◽  
pp. 392-406 ◽  
Author(s):  
D. Żyżelewicz ◽  
E. Nebesny ◽  
I. Motyl ◽  
Z. Libudzisz
Keyword(s):  
Ambient Temperature ◽  
High Temperatures ◽  
Functional Food ◽  
Lactobacillus Casei ◽  
Probiotic Bacteria ◽  
Live Cells ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Milk Chocolate ◽  
Live Bacterial Cells

Manufacturing of novel foodstuffs supplemented with live probiotic bacteria has recently been intensively investigated. The supplementation of confectionery with probiotics is troublesome since some unit technological processes are conducted at high temperatures and the products are usually stored at ambient temperature. Our group has developed a method of the production of milk chocolate, sweetened with either sucrose or isomalt and aspartame, containing 32, 36, or 40 g/100 g fat, and supplemented with live cells of probiotic bacterial strains: Lactobacillus casei and paracasei. This new milk chocolate displayed the same sensory properties as the reference, probiotic-free chocolate. The number of live bacterial cells was maintained at the functional level of 10<sup>6</sup> &divide; 10<sup>8</sup> cfu/g after keeping for 12 months irrespective of the temperature. The highest number of live probiotic bacteria survived in the chocolate kept at 4&deg;C. Thus the product can be regarded as functional food.

scholarly journals Adhesion ofE. coliBacteria Cells to Prosthodontic Alloys Surfaces Modified by TiO2Sol-Gel Coatings

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Katarzyna Banaszek ◽  
Witold Szymanski ◽  
Bożena Pietrzyk ◽  
Leszek Klimek
Keyword(s):  
Titanium Dioxide ◽  
Bacterial Adhesion ◽  
Culture Medium ◽  
Bacterial Culture ◽  
Bare Metal ◽  
Bacterial Cells ◽  
E Coli ◽  
Modified Surfaces ◽  
Bare Substrate ◽  
Scanning Electron

The evaluation of the degree of bacteriaE. coliadhesion to modified surfaces of the chosen prosthodontic alloys was presented. The study was carried out on Co-Cr (Wironit), Ni-Cr (Fantocer), and Fe-Cr-Ni (Magnum AN) alloys. Bare substrate as a control and titanium dioxide coated samples were used. The samples were placed for 24 hours in bacterial culture medium. After incubation period, a number of bacterial cells were evaluated by scanning electron microscope. The study revealed that modification of the alloy surfaces by titanium dioxide coating significantly decreases the amount of bacteria adhering to the surfaces and that additionally bare metal alloy substrates have a different degree of susceptibility to bacterial adhesion.

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