scholarly journals Structural Characterization of the Millennial Antibacterial (Fluoro)Quinolones—Shaping the Fifth Generation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1289
Author(s):  
Aura Rusu ◽  
Ioana-Andreea Lungu ◽  
Octavia-Laura Moldovan ◽  
Corneliu Tanase ◽  
Gabriel Hancu
Keyword(s):  
Bacterial Resistance ◽  
Structural Characteristics ◽  
Fourth Generation ◽  
Bacterial Strains ◽  
Fifth Generation ◽  
Pharmacokinetic Properties ◽  
Activity Spectrum ◽  
New Generation ◽  
New Compounds

The evolution of the class of antibacterial quinolones includes the introduction in therapy of highly successful compounds. Although many representatives were withdrawn due to severe adverse reactions, a few representatives have proven their therapeutical value over time. The classification of antibacterial quinolones into generations is a valuable tool for physicians, pharmacists, and researchers. In addition, the transition from one generation to another has brought new representatives with improved properties. In the last two decades, several representatives of antibacterial quinolones received approval for therapy. This review sets out to chronologically outline the group of approved antibacterial quinolones since 2000. Special attention is given to eight representatives: besifloxacin, delafoxacin, finafloxacin, lascufloxacin, nadifloxacin and levonadifloxacin, nemonoxacin, and zabofloxacin. These compounds have been characterized regarding physicochemical properties, formulations, antibacterial activity spectrum and advantageous structural characteristics related to antibacterial efficiency. At present these new compounds (with the exception of nadifloxacin) are reported differently, most often in the fourth generation and less frequently in a new generation (the fifth). Although these new compounds’ mechanism does not contain essential new elements, the question of shaping a new generation (the fifth) arises, based on higher potency and broad spectrum of activity, including resistant bacterial strains. The functional groups that ensured the biological activity, good pharmacokinetic properties and a safety profile were highlighted. In addition, these new representatives have a low risk of determining bacterial resistance. Several positive aspects are added to the fourth fluoroquinolones generation, characteristics that can be the basis of the fifth generation. Antibacterial quinolones class continues to acquire new compounds with antibacterial potential, among other effects. Numerous derivatives, hybrids or conjugates are currently in various stages of research.

scholarly journals Insecticidal Activity of Bacteria from Larvae Breeding Site with Natural Larvae Mortality: Screening of Separated Supernatant and Pellet Fractions

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 486 ◽  
Author(s):  
Handi Dahmana ◽  
Didier Raoult ◽  
Florence Fenollar ◽  
Oleg Mediannikov
Keyword(s):  
Biological Control ◽  
Insecticidal Activity ◽  
Breeding Site ◽  
Bacterial Strains ◽  
Activity Prediction ◽  
Pcr Screening ◽  
Breeding Sites ◽  
Insecticide Activity ◽  
New Compounds

Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides are banned due to environmental side effects or are of reduced efficacy due to resistance, biological control, including the use of bacterial strains with insecticidal activity, is of increasing interest and importance. The urgent actual need relies on the discovery of new compounds, preferably of a biological nature. Here, we explored the phenomenon of natural larvae mortality in larval breeding sites to identify potential novel compounds that may be used in biological control. From there, we isolated 14 bacterial strains of the phylum Firmicutes, most of the order Bacillales. Cultures were carried out under controlled conditions and were separated on supernatant and pellet fractions. The two fractions and a 1:1 mixture of the two fractions were tested on L3 and early L4 Aedes albopictus. Two concentrations were tested (2 and 6 mg/L). Larvae mortality was recorded at 24, 48 and 72 h and compared to that induced by the commercialized B. thuringiensis subsp. israelensis. Of the 14 strains isolated, 11 were active against the A. albopictus larvae: 10 of the supernatant fractions and one pellet fraction, and mortality increased with the concentration. For the insecticide activity prediction in three strains of the Bacillus cereus complex, PCR screening of the crystal (Cry) and cytolytic (Cyt) protein families characteristic to B. thuringiensis subsp. israelensis was performed. Most of the genes coding for these proteins’ synthesis were not detected. We identified bacterial strains that exhibit higher insecticidal activity compared with a commercial product. Further studies are needed for the characterization of active compounds.

scholarly journals Biosynthesis and Characterization of Bioplastic Poly-3-hydroxybutyrate from Hydrolyzate of Ulva using Bacillus subtilis rnM

2019 ◽  
Vol 31 (12) ◽  
pp. 2811-2815
Author(s):  
T. Revadhi ◽  
R. Nanthini
Keyword(s):  
Growth Conditions ◽  
Bacterial Strains ◽  
High Temperature And Pressure ◽  
Treatment Conditions ◽  
Wide Range ◽  
Nmr Techniques ◽  
Temperature And Pressure ◽  
Pre Treatment ◽  
New Generation

Biopolymers are a new generation biopolymers, which have wide range of applications. Poly-3-hydroxybutyrate (PHB) is one of the best biopolymers for replacement of non-biodegradable petroleum-based plastic and can be produced from organic wastes source by some bacterial strains under imbalance growth conditions. In present study, hydrolyzate was prepared from biomass of seaweed Ulva by acid pre-treated and used as a feedstock for PHB biosynthesis by Bacillu subtilis rnM. The pre-treatment was carried out by two different pre-treatment conditions such as room temperature and high temperature and pressure (HTP). The hydrolysate prepared by 2 % HCl at HTP supported for the maximum PHB biosynthesis than the other pre-treated conditions. The yield of PHB obtained by B. subtilis rnM when tested with laboratory grade sugars was lower to that achieved with hydrolysate of Ulva sp. The biosynthesized PHB was characterized by TGA, DSC, FTIR, XRD and NMR techniques.

scholarly journals Analysis of pedigree and inbreeding variation of Lithuanian indigenous wattle pigs

2017 ◽  
Vol 24 (2) ◽  
Author(s):  
Rūta Šveistienė ◽  
Violeta Razmaitė
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Fourth Generation ◽  
Effective Population ◽  
The Third ◽  
Fifth Generation ◽  
Sixth Generation ◽  
The Status ◽  
Population Breeding ◽  
New Generation

The objective of the study was to analyse the pedigree of pigs and to determine the level of their inbreeding, effective population size and interval between generations in the nucleus herd of restored and conserved Lithuanian indigenous wattle pig breed. The data of pedigree records on 329 Lithuanian indigenous wattle pigs were used for the analysis. The analysis was performed using the statistical programme PopReport. In the twelfth year of the restored population breeding, the completeness of pedigree in two first generations was 100%, in the third generation it was 99.1%, in the fourth generation 96.6%, in the fifth generation 93.6% and in the sixth generation it was 86.9%. The average interval between the generations was 3 years. From 2003 to 2013, the inbreeding coefficient of the introduced new generation increased by 10%. Due to the inbreeding increase in the last years the effective population size Ne of the nucleus decreased up to 12 and shows the general status of the whole population. The status of the breed remains critical-maintained.

scholarly journals A Novel “回” Pane Structure Multiband Microstrip Antenna for 2G/3G/4G/5G/WLAN/Navigation Applications

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zhen Yu ◽  
Ziheng Lin ◽  
Xiaoying Ran ◽  
Yao Li ◽  
Bing Liang ◽  
...  
Keyword(s):  
Dielectric Material ◽  
Design Method ◽  
Structural Characteristics ◽  
Impedance Matching ◽  
Relative Dielectric Constant ◽  
Fourth Generation ◽  
Wireless Applications ◽  
Fifth Generation ◽  
5G Technologies ◽  
Good Agreement

This work proposes a novel multiband slotted planar antenna with a “回” structure, which is similar to an ancient Chinese window grille structure. The antenna is suitable for wireless applications, including the second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G) technologies, as well as WLAN and navigation applications. The proposed antenna is based on the structural characteristics of a conventional monopole antenna, which combines the advantages of a slit structure and microstrip line structure for feeding. It adopts a circular patch with a slit structure placed in it, which is similar to the Chinese classical pane structure. This structure enables an effective reduction of the size of the antenna. The four-sided “回” gaps change the path of current flow and are coupled to each other, improving the impedance matching and radiation characteristics of the entire target frequency band. The antenna covers the frequency ranges of 1.58–1.77 GHz (12%), 2.1–2.50 GHz (17%), 3.61–4.09 GHz (12%), and 4.75–6.5 GHz (36%), permitting more than 10 wireless applications in these 4 frequency bands. This antenna uses an FR-4 dielectric material; the relative dielectric constant of the dielectric plate is 4.4, and the actual dimensions of the antenna are 85 × 70 × 1.6 mm³. The test and simulation results are in good agreement with each other, thus confirming that the proposed design method meets the requirements of various wireless applications.

scholarly journals Novel Therapeutic Trends in Pneumonia: Antibiotics and Mesenchymal Stem Cells

2021 ◽  
Author(s):  
Jennifer Ly ◽  
Qi Chu ◽  
Li Zhong
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Bacterial Resistance ◽  
Structural Characteristics ◽  
Combined Treatment ◽  
Management Strategies ◽  
Rabbit Model ◽  
Clinical Implementation ◽  
Bacterial Strains ◽  
Cell Therapies

Pneumonia remains a major cause of morbidity and mortality worldwide, especially during COVID-19 pandemic. With the significant global health burden that pneumonia poses, it is es-sential to improve therapeutic and management strategies. The increasing emergence of antibiotic resistant bacterial strains limits options for effective antibiotic use. New antibiotics for treatment of pneumonia may address deficits in current antimicrobial drugs, with an ability to cover both typical, atypical, and resistance pathogen. Several of these newer drugs also have structural characteristics that allow for a decreased propensity in development of bacterial resistance. Po-tential use of stem cell therapies in place of corticosteroid treatments may also offer an im-provement in patient outcomes. Human mesenchymal stem cell treatments have shown efficacy and safety in treating COVID-19 induced pneumonia. Combined treatment with both stem cells and antibiotics in pneumonia in a rabbit model has also shown significantly increased efficacy in comparison to antibiotic treatment alone, presenting yet another possible route for a novel strategy in treating pneumonia, though additional future studies are necessary before clinical implementation. While pneumonia remains a major disease of concern, having newer approved antibiotics as well as novel therapies such as stem cell treatments in the pipeline offers clinicians more options in effectively treating pneumonia.

scholarly journals Thiol and Disulfide Containing Vancomycin Derivatives Against Bacterial Resistance and Biofilm Formation

2021 ◽  
Author(s):  
Inga S. Shchelik ◽  
Karl Gademann
Keyword(s):  
Biofilm Formation ◽  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Resistant Bacteria ◽  
Bacterial Strains ◽  
Antibiotic Resistant ◽  
Promising Strategy ◽  
Vancomycin Resistant ◽  
New Compounds ◽  
Sulfur Containing

Antibiotic-resistant and biofilm-associated infections constitute a rapidly growing issue. The last resort antibiotic vancomycin is under threat, due to the increasing appearance of vancomycin resistant bacteria as well as the formation of biofilms. Herein, we report a series of novel vancomycin derivatives carrying thiol- and disulfide-containing moieties. The new compounds exhibited enhanced antibacterial activity against a broad range of bacterial strains, including vancomycin resistant microbes and Gram-negative bacteria. Moreover, all obtained derivatives demonstrated improved antibiofilm formation activity against VanB resistant Enterococcus compared to vancomycin. This work established a promising strategy for combating drug-resistant bacterial infections or disrupting biofilm formation and advances the knowledge on structural optimization of antibiotics with sulfur-containing modifications.

scholarly journals Novel Therapeutic Trends in Pneumonia: Antibiotics and Mesenchymal Stem Cells

2021 ◽  
Vol 4 (5) ◽  
pp. 01-10
Author(s):  
Li Zhong ◽  
Jennifer Ly ◽  
Qi Chu
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Bacterial Resistance ◽  
Structural Characteristics ◽  
Combined Treatment ◽  
Management Strategies ◽  
Rabbit Model ◽  
Clinical Implementation ◽  
Bacterial Strains ◽  
Cell Therapies

Pneumonia remains a major cause of morbidity and mortality. With the significant global health burden that pneumonia poses, it is essential to improve therapeutic and management strategies. The increasing emergence of antibiotic-resistant bacterial strains limits options for effective antibiotic use. New antibiotics for the treatment of pneumonia may address deficits in current antimicrobial drugs, with an ability to cover both typical, atypical, and resistant pathogens. Several of these newer drugs also have structural characteristics that allow for a decreased propensity for the development of bacterial resistance. The potential use of stem cell therapies in place of corticosteroid treatments may also offer an improvement in patient outcomes. Human mesenchymal stem cell treatments have shown efficacy and safety in treating COVID-19 induced pneumonia. Combined treatment with both stem cells and antibiotics in pneumonia in a rabbit model has also shown significantly increased efficacy in comparison to antibiotic treatment alone. This presents yet another possible route for a novel strategy in treating pneumonia, though additional future studies are necessary before clinical implementation. While pneumonia remains a major disease of concern, having newer approved antibiotics as well as novel therapies such as stem cell treatments in the pipeline offers clinicians more options in effectively treating pneumonia.

scholarly journals Characterization of Xanthomonas euvesicatoria strains pathogens of pepper in Serbia

2010 ◽  
Vol 25 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Maja Ignjatov ◽  
Katarina Gasic ◽  
Milan Ivanovic ◽  
Milan Sevic ◽  
Aleksa Obradovic ◽  
...  
Keyword(s):  
Copper Sulphate ◽  
Bacterial Resistance ◽  
Physiological Characteristics ◽  
Bacterial Strains ◽  
Pepper Leaves ◽  
Xanthomonas Euvesicatoria ◽  
The Republic ◽  
Differential Varieties

During spring and summer of 2008, 101 bacterial strains was isolated from the diseased pepper leaves collected from different pepper growing areas in the Republic of Serbia. The aim of this research was to characterize the isolated strains and determine their taxonomic position according to the most recent nomenclature. Pathogenic, biochemical and physiological characteristics of isolated bacteria were tested using standard bacteriological tests. The pathogen races were determined according to the reaction of differential varieties of Early Calwonder (ECW), their isogenic lines (ECW-10R, ECW-20R, ECW-30R) and Capsicum pubescens. The sensitivity of strains to bactericides was studied in vitro by culturing bacteria on sucrose pepton agar (SPA) plates, amended with filter-sterilized aqueous solution of streptomycin and kasugamycin (50, 100, 200 ppm) or copper-sulphate (100, 200 ppm). Based on pathogenic, biochemical and physiological characteristics, the investigated strains belonged to Xanthomonas euvesicatoria. The reaction of pepper differential varieties indicated that these strains belonged to pepper races P1, P3, P7, P8. Streptomycin resistant strains were not detected, but 6 strains were resistant to kasugamycin (50 ppm) and 13 strains to copper-sulphate (200 ppm), indicating bacterial resistance development.

scholarly journals Design, Synthesis and Characterization of Novel Isoxazole Tagged Indole Hybrid Compounds

2020 ◽  
Vol 18 (1) ◽  
pp. 138-148 ◽  
Author(s):  
Raed A. Al-Qawasmeh ◽  
Louy A. Al-Nazer ◽  
Sarah A. Dawlat-Kari ◽  
Luay Abu-Qatouseh ◽  
Salim S. Sabri ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Bacterial Strains ◽  
Anticancer Activities ◽  
Design Synthesis ◽  
X Ray ◽  
Hybrid Compounds ◽  
Indole Compounds ◽  
New Compounds ◽  
Single Crystal Analysis

AbstractSixteen new isoxazole tagged indole compounds have been synthesized via copper (I) catalyzed click chemistry of the aryl hydroxamoyl chloride and an indole containing alkyne moiety. The chemical structure of the synthesized compounds has been established using various physicochemical techniques. X-ray single crystal analysis of Ethyl 1-((3-phenylisoxazol-5-yl) methyl)-1H-indole-2-carboxylate (8a) has been analyzed. All compounds were tested for their antibacterial and anticancer activities. The activities for the new compounds were weak against both bacterial strains and the cancer cell lines.

Extraction and characterization of sea anemones compound and its Anti bacterial and hemolytic studies

2020 ◽  
Vol 10 (4) ◽  
pp. 93-97
Author(s):  
Anil Kumar A ◽  
Raja Sheker K ◽  
Naveen B ◽  
Abhilash G ◽  
Akila CR
Keyword(s):  
Antibacterial Activity ◽  
Focal Point ◽  
Haemolytic Activity ◽  
Klebsiella Pneumonia ◽  
Bacterial Strains ◽  
Sea Anemones ◽  
Marine Plants ◽  
Heteractis Magnifica ◽  
Trididemnum Solidum

Seas assets that give us a variety of characteristic items to control bacterial, contagious and viral ailment and mostly utilized for malignancy chemotherapy practically from spineless creatures, for example, bryozoans, wipes, delicate corals, coelenterates, ocean fans, ocean bunnies, molluscs and echinoderms. In the previous 30 - 40 years, marine plants and creatures have been the focal point of overall endeavours to characterize the regular results of the marine condition. Numerous marine characteristic items have been effectively exceptional to the last phases of clinical preliminaries, including dolastatin-10, a group of peptides disengaged from Indian ocean rabbit, Dollabella auricularia. Ecteinascidin-743 from mangrove tunicate Ecteinascidia turbinata, Didemnins was isolated from Caribbean tunicate Trididemnum solidum and Conopeptides from cone snails (Conus sp.), and a developing number of up-and-comers have been chosen as promising leads for expanded pre-clinical appraisals. Sea anemones possess numerous tentacles containing stinging cells or cnidocytes. The stinging cells are equipped with small organelles known as nematocysts. The two species of sea anemones namely, Heteractis magnificaandStichodactyla haddoni, were collected from Mandapam coastal waters of Ramanathapuram district, Tamilnadu, India. The Nematocyst was collected and centrifuged, and the supernatant was lyophilized and stored for further analysis. The amount of protein from Heteractis Magnifica and Stichodactyla haddoni was estimated. The crude extract has shown haemolytic activity on chicken blood and goat blood. In the antibacterial activity of the sea anemone against six bacterial strains Staphylococcus aureus, Salmonella typhii, Salmonella paratyphii, Klebsiella pneumonia, Vibrio cholerae, Pseudomonas aeruginosa. Antibacterial activity of H. Magnifica and S.haddoni was measured as the radius of the zone of inhibition.

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