scholarly journals Determination of Antibacterial Activity of Cell Free Extracts of Lactobacillus bulgaricus and Streptococcus thermophilus against Local Isolates of E. coli O157:H7

2019 ◽  
Vol 7 (3) ◽  
pp. 22-31
Author(s):  
Zainab M. AlZubaidy
Keyword(s):  
Antibacterial Activity ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
E Coli

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

scholarly journals Evaluation of the Antibacterial Activity of 5-(thiophen-2-yl)-1H-tetrazole and Its Oxime Derivative against ATCC Reference Strains and Strains Isolated from the Hospital Environment of a Provincial Public Hospital in the City of Fez

2021 ◽  
Vol 2 (2) ◽  
pp. 16-24
Author(s):  
Sara Hajib ◽  
Mohamed Hssaini ◽  
Anouar Alami ◽  
Hicham Bekkari ◽  
Najoua Benchemsi ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Resistance ◽  
Antibacterial Activities ◽  
Bactericidal Effect ◽  
Hospital Environment ◽  
Diffusion Method ◽  
E Coli ◽  
Tetrazole Derivatives ◽  
Reference Strains

Bacterial resistance to antibiotics and disinfectants has become a real concern. The hospital presents a favorable environment for the colonization and development of bacteria resistant to antibiotics and disinfectants. The search for new antimicrobial compounds is essential to combat this phenomenon. Tetrazole derivatives may represent a solution due to their interesting antibacterial activity. In this work, two tetrazole derivatives; thiophene-2-carbaldehyde (T2C) and 5-(thiophen-2-yl)-1H-tetrazole (5TPh-1HT), were evaluated for their antibacterial activities against a set of reference strains and strains isolated from the hospital environment. The antibacterial effect was studied by the disc diffusion method and by determination of MIC and MBC. The 5-(thiophen-2-yl)-1H-tetrazole (5TPh-1HT) has a broader spectrum of activity than its oxime derivative (T2C). The latter has bactericidal activity only on gram-negative Escherichia coli, Pseudomonas aeruginosa with MICs ranging from 0.62 mg/ml to 2.5 mg/ml, while 5TPh-1HT has a bactericidal effect on all strains with MICs ranging from 0.62 mg/ml to 1.25 mg/ml. Both products have a significant inhibitory activity on the strains tested in particular E. coli H, S. aureus H, P. aeruginosa and Streptococcus spp A. It was found that these activities vary depending on the microbial strain tested and the product applied.

Antibacterial Activity of Yogurt Starter in Cow and Buffalo Milk

1979 ◽  
Vol 42 (8) ◽  
pp. 664-665 ◽  
Author(s):  
JASJIT SINGH ◽  
ADARSH KHANNA ◽  
BARISH CHANDER
Keyword(s):  
Antibacterial Activity ◽  
Streptococcus Thermophilus ◽  
Buffalo Milk ◽  
Comparative Assessment ◽  
Lactobacillus Bulgaricus ◽  
Cow Milk ◽  
Antagonistic Action ◽  
Pseudomonas Fragi ◽  
Test Organisms ◽  
Pronounced Inhibition

A comparative assessment of the antibacterial activity of pure and mixed-strain cultures of Streptococcus thermophilus and Lactobacillus bulgaricus against Escherichia coli. Staphylococcus aureus, Pseudomonas fragi and Micrococcus flavus was made using cow and buffalo milk. A culture filtrate from S. thermophilus exhibited no antagonistic action against any of the test organisms, irrespective of the type of milk used and the period of incubation. Culture filtrates from L. bulgaricus and the mixed culture caused pronounced inhibition of all the test organisms used. Antibacterial activity of yogurt culture was greater in buffalo than cow milk.

Simultaneous Enumeration of the Characteristic Microorganisms in Yogurt Using the Hydrophobic Grid Membrane Filter System

1990 ◽  
Vol 53 (1) ◽  
pp. 64-66 ◽  
Author(s):  
GEORGE E. MILLARD ◽  
ROBIN C. MCKELLAR ◽  
RICHARD A. HOLLEY
Keyword(s):  
Membrane Filter ◽  
Streptococcus Thermophilus ◽  
Membrane System ◽  
Lactobacillus Bulgaricus ◽  
Excellent Correlation ◽  
Light Blue ◽  
Single Plate ◽  
Dark Blue ◽  
International Dairy Federation

Utilization of the hydrophobic grid membrane system (HGMF) in conjunction with erioglaucine-supplemented tryptone-phytone-yeast extract (TPYE) agar permitted the differential enumeration of Streptococcus thermophilus and Lactobacillus bulgaricus in yogurt. An anaerobic incubation of 42°C resulted in conditions under which streptococcal colonies were light blue and the lactobacillus colonies were a distinct dark blue. Excellent correlation was achieved when the above method was compared with the International Dairy Federation Standard 117:1983 by coincident analysis of 12 commercial yogurts. The method allowed a reliable single plate determination of cocci to rod ratios from 20:1 to 1:5.

scholarly journals Antibacterial Activity and Chemical Composition of Turkish Propolis

2001 ◽  
Vol 56 (11-12) ◽  
pp. 1112-1115 ◽  
Author(s):  
Nevin Keskin ◽  
Selçuk Hazir ◽  
K. Hüsnü Can Baser ◽  
Mine Kürkçüoglu
Keyword(s):  
Antibacterial Activity ◽  
Chemical Compounds ◽  
Antibacterial Activities ◽  
Fatty Acid Esters ◽  
E Coli ◽  
Weak Activity ◽  
Gram Positive Cocci ◽  
Acid Esters

Abstract The antibacterial activities of propolis samples have been examined in vitro, according to the principles accepted for the determination of a similar activity of antibiotics with the use of solid and liquid media. It has been found that propolis extracts showed antibacterial activity through a range of commonly encountered gram positive cocci (5. aureus, beta hem. Streptococus), but had weak activity against gram negative bacteria (E . coli, P. aeruginosa). GC/MS analysis showed that propolis samples contain a variety of chemical compounds in­ cluding aromatic compounds, fatty acid esters and sesquiterpenes.

scholarly journals Obtención, caracterización y evaluación de dos preparados candidatos a probióticos desarrollados con residuos agroindustriales

2018 ◽  
pp. 6487-6499
Author(s):  
José E. Miranda-Yuquilema ◽  
Alfredo Marin-Cárdenas ◽  
Davinia Sánchez-Macías ◽  
Yaneisy García-Hernández
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lactobacillus Acidophilus ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Salmonella Spp ◽  
Kluyveromyces Fragilis ◽  
E Coli

Objetivo. Obtener, caracterizar y evaluar dos biopreparados desarrollados a partir de melaza de caña de azúcar - vinaza de naranja fermentados con levaduras y/o bacterias ácido lácticas. Materiales y métodos. Se utilizó un diseño completamente aleatorizado con cinco repeticiones por tratamiento. Los tratamientos evaluados fueron: T1, Lactobacillus acidophilus, Lactobacillus bulgaricus, Streptococcus thermophilus y T2, las bacterias anteriores más Saccharomyces cerevisiae y Kluyveromyces fragilis (L-4 UCLV). En un sustrato compuesto por melaza- vinaza se inocularon los microorganismos anteriormente mencionados y estos fueron incubados a 37ºC por 24 h. Se les determinaron a los biopreparados los parámetros fisicoquímicos, microbiológico y se realizaron las pruebas in vitro para evaluar la capacidad probiótica. Resultados. Ambos biopreparados presentaron un color marrón oscuro, dulzón y con pH inferior a 4. El comportamiento bromatológicos y microbiológicos fueron mayores (p>0.05) en el T2. En ambos biopreparados la viabilidad fue superior a 92%. En pruebas in vitro, ambos biopreparados fueron resistentes a pH ácido, sales biliares, amplio espectro de actividad antimicrobiana y efecto inhibitorio a la E. coli, Salmonella spp. y S. aureus. Conclusión. Los biopreparados obtenidos a partir de melaza de caña de azúcar-vinaza de naranja fermentados con levaduras y/o bacterias ácido lácticas demostraron propiedades físicoquímicas, microbiológicas apropiadas para productos probióticos. En las pruebas in vitro, se demostró su efecto potencial como probiótico.

Concentration determination of chromatin in unstained resin-embedded sections by means of Z-contrast in STEM

1990 ◽  
Vol 48 (2) ◽  
pp. 186-187
Author(s):  
M. Haider ◽  
B. Bohrmann
Keyword(s):  
Energy Loss ◽  
Freeze Substitution ◽  
Biological Macromolecules ◽  
Local Concentration ◽  
E Coli ◽  
Concentration Determination ◽  
Phosphorous Content ◽  
Z Contrast ◽  
Electron Energy Loss

The technique of Z-contrast in STEM offers the possibility to determine the local concentration of macromolecules like lipids, proteins or DNA. Contrast formation depends on the atomic composition of the particular structure. In the case of DNA, its phosphorous content discriminates it from other biological macromolecules. In our studies, sections of E. coli, the dinoflagellate Amphidinium carterae and Euglena spec. cells were used which were obtained by cryofixation followed by freeze-substitution into acetone with 3% glutaraldehyde. The samples were then embedded either in Lowicryl HM20 at low temperature or in Epon at high temperature. Sections were coated on both sides with 30Å carbon.The DF- and the inelastic image have been recorded simultaneously with a Cryo-STEM. This Cryo-STEM is equipped with a highly dispersive Electron Energy Loss Spectrometer. With this instrument pure Z-contrast can be achieved either with a Filtered DF-image divided by the inelastic image or, as is used in this paper, by dividing the conventional DF-image by an inelastic image which has been recorded with an inelastic detector whose response is dependent on the total energy loss of the inelastically scattered electrons.

Co-expression of recombinant single chain variable fragment recognizing blood antigen fused with sumo and chaperones in Escherichia coli

2018 ◽  
Vol 40 (4) ◽  
Author(s):  
Dang Thi Ngoc Ha ◽  
Le Thi Thu Hong ◽  
Truong Nam Hai
Keyword(s):  
Recombinant Antibody ◽  
Blood Type ◽  
Soluble Form ◽  
Supernatant Fraction ◽  
Blood Group Antigens ◽  
Single Chain ◽  
E Coli ◽  
Recombinant Scfv ◽  
Single Chain Variable Fragments

Single chain variable fragments (scFv) have widely been used in research, diagnosis and treatment, but the scFv is considered as difficult protein for expression in E. coli. In previous studies, we expressed a construction of recombinant single chain variable fragments again antigen specific for blood type A (antiA-scFv) individually or fused with Trx or SUMO. However, soluble fraction was low abandant and only approximately 40% when fused with Trx, the other cases were expressed in form of inclusion body. Therefore, it was difficult for purification, refolding and activity assesment. In thispaper, we demonstrated a suitable construction for soluble production of antiA-scFv fused with SUMO (SM/antiA-scFv) in presence of chaparones. Under fermentation with 0.1 mM IPTG at 20oC, the SM/antiA-scFv was entirely expressed in soluble form. Importantly, after cleavage from SUMO with SUMOprotease, antiA-scFv was still maintained in the supernatant fraction. Therefore, it can help ensure bioactivity and is useful for purification process. To the best of our knowledge, this is the first report showing soluble recombinant scFv fused with SUMO in presence of chaperone for determination of blood group antigens. Thus, this result facilitates the optimal study of soluble expression, purification and bioactivity determination of the antiA-scFv recombinant antibody. 

Antibacterial Activity of Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa

2017 ◽  
Vol 8 (03) ◽  
Author(s):  
Kyoung- Sun Seo ◽  
Seong Woo Jin ◽  
Seongkyu Choi ◽  
Kyeong Won Yun
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Antibacterial Agent ◽  
Methanol Extract ◽  
The Other ◽  
Diffusion Method ◽  
E Coli ◽  
Agar Diffusion ◽  
Agar Diffusion Method ◽  
Crude Methanol Extract

The antibacterial activity of three Cupressaceae plants (Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa) was tested against three bacteria using the agar diffusion method. The ether and ethylacetate fraction of crude methanol extract from the three plants showed potent antibacterial activity against the tested microorganisms. The result showed that Staphylococcus aureus revealed the most sensitivity among the tested bacteria. Thujaoccidentalisether fraction and Thujaorientalis hexane fraction exhibited the highest antibacterial activity against Staphylococcus aureus. E. coli was shown the highest MIC values compared to the other two tested bacteria, which indicates the lowest antibacterial activity against the bacterium. This study promises an interesting future for designing a potentially active antibacterial agent from the three Cupressaceae plants.

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