Project description:Thermal proteome profiling of E. coli lysate treated with fosfomycin (0.2 mg/ml). Untargeted proteomics with microflow method and with 60 min gradient.
Project description:E.coli ATCC 25922 was overnight grown in 10 ml LB and passaged for 3 h with 1:50 dilution in fresh LB. Treated with tavaborole alone (80 μg/ml, labeled ‘A’) or tavaborole plus amikacin (80 μg/ml +40 μg/ml, labeled ‘AK’) for 6 h, cells were washed in PBS and harvested by centrifugation at 4,000 g, 8 min. After liquid nitrogen flash freezing, cells were stored at -80 °C and transported to company for following experiments
Project description:Genome-wide transcriptional analysis was performed on E. coli K12 exposed to 1 mg/ml of olive vegetation water phenolic extract (OVWPE) in planktonic condition.
Project description:Red fruits are valued for their vitamin C and polyphenol content, but traditional heat preservation methods used in juice and nectar production can significantly reduce these components. Therefore, alternative non-thermal methods are explored to inactivate foodborne pathogens like Escherichia coli while maintaining the nutritional value. However, knowledge about the effects of these technologies on bacterial cells is limited. This study analyzed differentially expressed genes of E. coli ATCC 8739 inoculated in strawberry nectar after exposure to three treatments with two sets of parameters each, namely thermal treatment, high-pressure processing (HPP), and moderate-intensity pulsed electric field (MIPEF). The highest inactivation efficiency was achieved with HPP at 400 MPa, 1 min, reducing microbial counts by 5.0±0.3 log cfu/mL, and thermal treatment at 60°C, 200 s, achieving a reduction of 4.4±0.2 log cfu/mL, while no inactivation was observed with MIPEF at 6 kV/cm. Transcriptomic analysis showed that thermal and HPP treatments caused similar molecular stress responses in E. coli. In both cases, the most overexpressed genes encoded outer membrane proteins, which may lead to the activation of the envelope stress response. Despite no microbial inactivation was revealed after MIPEF treatment, strong transcriptomic responses were observed, particularly in genes related to membrane integrity and metabolic activity. Numerous overexpressed genes associated with ABC transporters, outer membrane proteins, and lipoproteins were identified, which could increase the strain’s virulence. This study provides insights into the stress response mechanisms induced by conventional and novel treatments. Nevertheless, further research is needed to investigate the long-term effects on bacterial populations.
Project description:Apidaecins are a series of proline-rich, 18- to 20-residue antimicrobial peptides produced by insects. They are predominantly active against the gram-negative bacteria. Previous studies mainly focused on the identification of their internal macromolecular targets, few addressed on the action of apidaecins on the molecules, especially proteins, of bacterial cell membrane. In this study, iTRAQ-coupled 2-D LC-MS/MS technique was utilized to identify altered membrane proteins of Escherichia coli cells incubated with one isoform of apidaecins--apidaecin IB. Cell division protease ftsH, an essential regulator in maintenance of membrane lipid homeostasis, was found to be overproduced in cells incubated with apidaecin IB. Its over-expression intensified the degradation of cytoplasmic protein UDP-3-O-acyl-N- acetylglucosamine deacetylase, which catalyzes the first committed step in the biosynthesis of the lipid A moiety of LPS, and thus leaded to the further unbalanced biosynthesis of LPS and phospholipids. Our findings suggested a new antibacterial mechanism of apidaecins and perhaps, by extension, for other proline-rich antimicrobial peptides.
Project description:AimsThe identification and differentiation of antibiotic-resistant bacteria by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) profiling remains a challenge due to the difficulty in detecting unique protein biomarkers associated with this trait. To expand the detectable proteome in antibiotic-resistant bacteria, we describe a method implementing offline LC protein separation/fractionation prior to MALDI-ToF-MS and top-down MALDI-ToF/ToF-MS (tandem MS or MS/MS) for the analysis of several antibiotic-resistant Escherichia coli isolates.Methods and resultsCoupling offline LC with MALDI-ToF-MS increased the number of detected protein signals in the typically analyzed mass regions (m/z 3000-20 000) by a factor of 13. Using the developed LC-MALDI-ToF-MS protocol in conjunction with supervised principal components analysis, we detected a protein biomarker at m/z 9355 which correlated to β-lactam resistance among the E. coli bacteria tested. Implementing a top-down MALDI-ToF/ToF-MS approach, the prefractionated protein biomarker was inferred as a DNA-binding HU protein, likely translated from the blaCMY-2 gene (encoding AmpC-type β-lactamase) in the incompatibility plasmid complex A/C (IncA/C).ConclusionsOur results demonstrate the utility of LC-MALDI-MS and MS/MS to extend the number of proteins detected and perform MALDI-accessible protein biomarker discovery in microorganisms.Significance and impact of the studyThis outcome is significant since it expands the detectable bacterial proteome via MALDI-ToF-MS.
Project description:Immunoaffinity Purifications of Human Argonaute Twelve hours after transfections with mock or with miR-124, we washed each 15-cm plate once with phosphate-buffered saline (usually two plates were used per IP), then added 1 ml of 4 C lysis buffer (150 mM KCl, 25 mM Tris-HCl [pH 7.4], 5 mM Na-EDTA [pH 8.0], 0.5% Nonidet P-40, 0.5 mM DTT, 10 ul protease inhibitor cocktail [Pierce Cat# 78437], 100 U/ml SUPERaseIn [Ambion Cat# AM2694]). Following a 30-min incubation at 4 C, we scraped the plates, combined the lysates, and then spun them at 4 C for 30 min at 14,000 RPM in a microcentrifuge. We collected the supernatant and filtered it through a 0.45-um syringe filter. We froze an aliquot of lysate in liquid nitrogen for reference RNA isolation. We then added 0.22 mg/ml heparin to the lysate. We mixed the lysate with 2.5 mg of Dynal m-280 streptavidin beads (250 ul from original storage solution) coupled to biotinylated 4F9 ago antibody (~12.5 ug), which we equilibrated immediately prior to use by washing twice with 1 ml of lysis buffer. We incubated the beads with the lysate for 2 h at 4 C and then washed the beads twice with 1.25 ml of ice-cold lysis buffer for 5-min each. Five percent of the beads were frozen for SDS PAGE analysis after the second wash. RNA was extracted directly from the remaining beads using lysis buffer from Invitrogen's Micro-to-Midi kit (Invitrogen Cat# 12183-018). We purified RNA from the lysate and RNA extracted from the beads with the Micro-to-Midi kit as per vender's instructions, except that the percentage isopropanol used for binding to the column was 70%, instead of 33%, to promote the binding of small RNAs. RNA was amplified with ambion kit 1755. RNA from total cell lysate was labeled with cy3 and IPd RNA was labeled with cy5
Project description:Genome-wide transcriptional analysis was performed on E. coli K12 exposed to 1 mg/ml of olive vegetation water phenolic extract (OVWPE) in planktonic condition. Three groups of samples were considered: P group (three replicate cultures with OVWPE extract diluted in ethanol 20%), E group (three replicate cultures with ethanol 20% alone) C group (three control replicate cultures). 1 ml of VWPE extract (1 mg/ml), 1 ml of ethanol 20% and 1 ml of LB broth were added respectively to the three groups when the OD600 of each culture reached 0.4. Cultures were sampled (2 ml) at the time of treatment (t1), 20 (t2) and 40 (t3) minutes after treatment.
Project description:Biotechnology has transformed the production of various chemicals and pharmaceuticals due to its efficient and selective processes, but it is inherently limited by its use of live cells as 'biocatalysts.' Cell-free expression (CFE) systems, which use a protein lysate isolated from whole cells, have the potential to overcome these challenges and broaden the scope of biomanufacturing. Implementation of CFE systems at scale will require determining clear markers of lysate activity and developing supplementation approaches that compensate for potential variability across batches and experimental protocols. Towards this goal, we use metabolomics to relate lysate preparation and performance to metabolic activity. We show that lysate processing affects the metabolite makeup of lysates, and that lysate metabolite levels change over the course of a CFE reaction regardless of whether a target compound is produced. Finally, we use this information to develop ways to standardize lysate activity and to design an improved CFE system.