In vitro antibacterial activities and molecular characterization of bacterial species isolated from farmlands against selected pathogens

ABSTRACT Antibiotics with novel mechanisms of action are becoming increasingly important in the battle against bacterial resistance to all currently used classes of antibiotics. Bacterial DNA gyrase and topoisomerase IV (topoIV) are the familiar targets of fluoroquinolone and coumarin antibiotics. Here we present the characterization of two members of a new class of synthetic bacterial topoII ATPase inhibitors: VRT-125853 and VRT-752586. These aminobenzimidazole compounds were potent inhibitors of both DNA gyrase and topoIV and had excellent antibacterial activities against a wide spectrum of problematic pathogens responsible for both nosocomial and community-acquired infections, including staphylococci, streptococci, enterococci, and mycobacteria. Consistent with the novelty of their structures and mechanisms of action, antibacterial potency was unaffected by commonly encountered resistance phenotypes, including fluoroquinolone resistance. In time-kill assays, VRT-125853 and VRT-752586 were bactericidal against Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, and Haemophilus influenzae, causing 3-log reductions in viable cells within 24 h. Finally, similar to the fluoroquinolones, relatively low frequencies of spontaneous resistance to VRT-125853 and VRT-752586 were found, a property consistent with their in vitro dual-targeting activities.

Download Full-text

SureSelect targeted enrichment, a new cost effective method for the whole genome sequencing of Candidatus Liberibacter asiaticus

Scientific Reports ◽

10.1038/s41598-019-55144-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Weili Cai ◽

Schyler Nunziata ◽

John Rascoe ◽

Michael J. Stulberg

Keyword(s):

Whole Genome Sequencing ◽

Molecular Characterization ◽

Genome Sequencing ◽

Whole Genome Sequence ◽

Whole Genome ◽

Genome Coverage ◽

Metagenomic Sample ◽

Liberibacter Asiaticus

AbstractHuanglongbing (HLB) is a worldwide deadly citrus disease caused by the phloem-limited bacteria ‘Candidatus Liberibacter asiaticus’ (CLas) vectored by Asian citrus psyllids. In order to effectively manage this disease, it is crucial to understand the relationship among the bacterial isolates from different geographical locations. Whole genome sequencing approaches will provide more precise molecular characterization of the diversity among populations. Due to the lack of in vitro culture, obtaining the whole genome sequence of CLas is still a challenge, especially for medium to low titer samples. Hundreds of millions of sequencing reads are needed to get good coverage of CLas from an HLB positive citrus sample. In order to overcome this limitation, we present here a new method, Agilent SureSelect XT HS target enrichment, which can specifically enrich CLas from a metagenomic sample while greatly reducing cost and increasing whole genome coverage of the pathogen. In this study, the CLas genome was successfully sequenced with 99.3% genome coverage and over 72X sequencing coverage from low titer tissue samples (equivalent to 28.52 Cq using Li 16 S qPCR). More importantly, this method also effectively captures regions of diversity in the CLas genome, which provides precise molecular characterization of different strains.

Download Full-text

The Proteome of Brain Capillary Endothelial Cells: Toward a Molecular Characterization of an In Vitro Blood–Brain Barrier Model

Expression Profiling in Neuroscience - Neuromethods ◽

10.1007/978-1-61779-448-3_10 ◽

2011 ◽

pp. 161-179 ◽

Cited By ~ 2

Author(s):

Sophie Duban-Deweer ◽

Christophe Flahaut ◽

Yannis Karamanos

Keyword(s):

Endothelial Cells ◽

Molecular Characterization ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Brain Capillary ◽

Blood Brain Barrier Model ◽

Capillary Endothelial Cells ◽

Barrier Model

Download Full-text

Discovery and Characterization of Low-Molecular Weight Inhibitors of Erwinia tracheiphila

Phytopathology ◽

10.1094/phyto-11-19-0440-r ◽

2020 ◽

Vol 110 (5) ◽

pp. 989-998

Author(s):

Cláudio M. Vrisman ◽

Loïc Deblais ◽

Yosra A. Helmy ◽

Reed Johnson ◽

Gireesh Rajashekara ◽

...

Keyword(s):

Pseudomonas Syringae ◽

High Throughput Screening ◽

Pathogenic Bacteria ◽

Bacterial Species ◽

Bacillus Species ◽

Erwinia Tracheiphila ◽

Static Activity ◽

Low Toxicity

Plant pathogenic bacteria in the genus Erwinia cause economically important diseases, including bacterial wilt of cucurbits caused by Erwinia tracheiphila. Conventional bactericides are insufficient to control this disease. Using high-throughput screening, 464 small molecules (SMs) with either cidal or static activity at 100 µM against a cucumber strain of E. tracheiphila were identified. Among them, 20 SMs (SM1 to SM20), composed of nine distinct chemical moiety structures, were cidal to multiple E. tracheiphila strains at 100 µM. These lead SMs had low toxicity to human cells and honey bees at 100 µM. No phytotoxicity was observed on melon plants at 100 µM, except when SM12 was either mixed with Silwet L-77 and foliar sprayed or when delivered through the roots. Lead SMs did not inhibit the growth of beneficial Pseudomonas and Enterobacter species but inhibited the growth of Bacillus species. Nineteen SMs were cidal to Xanthomonas cucurbitae and showed >50% growth inhibition against Pseudomonas syringae pv. lachrymans. In addition, 19 SMs were cidal or static against Erwinia amylovora in vitro. Five SMs demonstrated potential to suppress E. tracheiphila when foliar sprayed on melon plants at 2× the minimum bactericidal concentration. Thirteen SMs reduced Et load in melon plants when delivered via roots. Temperature and light did not affect the activity of SMs. In vitro cidal activity was observed after 3 to 10 h of exposure to these five SMs. Here, we report 19 SMs that provide chemical scaffolds for future development of bactericides against plant pathogenic bacterial species.

Download Full-text

Molecular Characterization of HOXA2 and HOXA3 Binding Properties

Journal of Developmental Biology ◽

10.3390/jdb9040055 ◽

2021 ◽

Vol 9 (4) ◽

pp. 55

Author(s):

Joshua Mallen ◽

Manisha Kalsan ◽

Peyman Zarrineh ◽

Laure Bridoux ◽

Shandar Ahmad ◽

...

Keyword(s):

Transcription Factors ◽

Molecular Characterization ◽

Sequence Motif ◽

Body Parts ◽

Binding Affinities ◽

Binding Properties ◽

Functional Consequences

The highly conserved HOX homeodomain (HD) transcription factors (TFs) establish the identity of different body parts along the antero–posterior axis of bilaterian animals. Segment diversification and the morphogenesis of different structures is achieved by generating precise patterns of HOX expression along the antero–posterior axis and by the ability of different HOX TFs to instruct unique and specific transcriptional programs. However, HOX binding properties in vitro, characterised by the recognition of similar AT-rich binding sequences, do not account for the ability of different HOX to instruct segment-specific transcriptional programs. To address this problem, we previously compared HOXA2 and HOXA3 binding in vivo. Here, we explore if sequence motif enrichments observed in vivo are explained by binding affinities in vitro. Unexpectedly, we found that the highest enriched motif in HOXA2 peaks was not recognised by HOXA2 in vitro, highlighting the importance of investigating HOX binding in its physiological context. We also report the ability of HOXA2 and HOXA3 to heterodimerise, which may have functional consequences for the HOX patterning function in vivo.

Download Full-text

Molecular characterization of the grape seeds extract’s effect against chemically induced liver cancer: In vivo and in vitro analyses

Scientific Reports ◽

10.1038/s41598-018-19492-x ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 31

Author(s):

Alaaeldin Ahmed Hamza ◽

Gehan Hussein Heeba ◽

Hanan Mohamed Elwy ◽

Chandraprabha Murali ◽

Raafat El-Awady ◽

...

Keyword(s):

Liver Cancer ◽

Molecular Characterization ◽

Grape Seeds ◽

Chemically Induced

Download Full-text

Synthesis and Antibacterial Activities of Amidine Substituted Monocyclic β-Lactams

Medicinal Chemistry ◽

10.2174/1573406417666210830122954 ◽

2021 ◽

Vol 17 ◽

Author(s):

Lijuan Zhai ◽

Lili He ◽

Yuanbai Liu ◽

Ko Ko Myo ◽

Zafar Iqbal ◽

...

Keyword(s):

Antibacterial Activity ◽

Bacterial Species ◽

Antimicrobial Effect ◽

Antibacterial Activities ◽

Lead Target ◽

Bacterial Strains ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Clinical Interest

Background: Mononcyclic β-lactams are regarded as the most resistant class of β-lactams against a series of β-lactamases though possess limited antibacterial activity. Aztreonam being the first clinically approved monobactam needs broad-spectrum efficacy through structural modification. Objective: We strive to synthesize a number of monocyclic β-lactams by varying the substituents at N1, C3 and C4 positions of azetidinone ring and study the antimicrobial effect on variable bacterial strains. Methods: Seven new monobactam derivatives 23a-g, containing substituted-amidine moieties linked to the azetidinone ring via thiazole linker, were synthesized through multistep synthesis. The final compounds were investigated for their in vitro antibacterial activities using broth microdilution method, against ten bacterial strains of clinical interest. The minimum inhibitory concentrations (MICs) of newly synthesized derivatives were compared with aztreonam, ceftazidime and meropenem, existing clinical antibiotics. Results: All compounds 23a-g showed higher antibacterial activities (MIC 0.25 µg/mL to 64 µg/mL) against tested strains as compared to aztreonam (MIC 16 µg/mL to >64 µg/mL) and ceftazidime (MIC >64 µg/mL). However all compounds, except 23d, exhibited lower antibacterial activity against all tested bacterial strains as compared to meropenem. Conclusion: Compound 23d showed comparable or improved antibacterial activity (MIC 0.25 µg/mL to 2 µg/mL) to meropenem (MIC 1 µg/mL to 2 µg/mL) in case of seven bacterial species. Therefore, compound 23d may be valuable lead target for further investigations against multi-drug resistant Gram-negative bacteria.

Download Full-text

Characterization of Novel Antimicrobial Peptoids

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.6.1429 ◽

1999 ◽

Vol 43 (6) ◽

pp. 1429-1434 ◽

Cited By ~ 87

Author(s):

Bob Goodson ◽

Anton Ehrhardt ◽

Simon Ng ◽

John Nuss ◽

Kirk Johnson ◽

...

Keyword(s):

Antibacterial Activities ◽

Membrane Disruption ◽

Infection Model ◽

Gram Negative Bacteria ◽

Positional Isomers ◽

Bacterial Growth Inhibition ◽

Alpha Carbon

ABSTRACT Peptoids differ from peptides in that peptoids are composed of N-substituted rather than alpha-carbon-substituted glycine units. In this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition. In vitro, the peptoid CHIR29498 and some of its analogues were active in the range of 3 to 12 μg/ml against a panel of gram-positive and gram-negative bacteria which included isolates which were resistant to known antibiotics. Peptoid antimicrobial activity againstStaphylococcus aureus was rapid, bactericidal, and independent of protein synthesis. β-Galactosidase and propidium iodide leakage assays indicated that the membrane is the most likely target of activity. Positional isomers of an active peptoid were also active, consistent with a mode of action, such as membrane disruption, that does not require a specific fit between the molecule and its target. In vivo, CHIR29498 protected S. aureus-infected mice in a simple infection model.

Download Full-text