Combination treatment of MCF-7 spheroids by Pseudomonas aeruginosa HI1 levan and cisplatin

Protein aggregation monitoring in cells under oxidative stress: a novel fluorescent probe based on a 7-azaindole-BODIPY derivative

The development of new fluorescent probes as molecular sensors is a critical step for the understanding of molecular mechanisms. BODIPY-based probes offer versatility due to their high fluorescence quantum yields, photostability, and tunable absorption/emission wavelengths. Here, we report the synthesis and evaluation of a novel 7-azaindole-BODIPY derivative to probe hydrophobic proteins as well as protein misfolding and aggregation. In organic solvents, this compound shows two efficiently interconverting emissive excited states. In aqueous environments, it forms molecular aggregates with unique photophysical properties. The complex photophysics of the 7-azaindole-BODIPY derivative was explored for sensing applications. In the presence of albumin, the compound is stabilized in hydrophobic protein regions, significantly increasing its fluorescence emission intensity and lifetime. Similar effects occur in the presence of protein aggregates but not with other macromolecules like pepsin, DNA, Ficoll 40, and coconut oil. Fluorescence lifetime imaging microscopy (FLIM) and two-photon fluorescence microscopy on breast (MCF-7) and lung (A549) cancer cells incubated with this compound display longer fluorescence lifetimes and higher emission intensity under oxidative stress. Synchrotron FTIR micro spectroscopy confirmed that the photophysical changes observed were due to protein misfolding and aggregation caused by the oxidative stress. These findings demonstrate that this compound can serve as a fluorescent probe to monitor protein misfolding and aggregation triggered by oxidative stress.

Prebiotic-mediated gastroprotective potentials of three bacterial levans through NF-κB-modulation and upregulation of systemic IL-17A

This study aimed to investigate whether the gastroprotective effects of three types of bacterial levans are correlated with their prebiotic-associated anti-inflammatory/antioxidant potentials. Three levans designated as LevAE, LevP, and LevZ were prepared from bacterial honey isolates; purified, and characterized using TLC, NMR, and FTIR. The anti-inflammatory properties of levan preparations were assessed in LPS-stimulated RAW 264.7 cell lines, while their safety and gastroprotective potentials were assessed in Wistar rats. The three levans significantly reduced ulcer number (22.29-70.05 %) and severity (31.76-80.54 %) in the ethanol-induced gastric ulcer model compared to the control (P < 0.0001/each), with the highest effect observed in LevAE and levZ (200 mg/each) (P < 0.0001). LevZ produced the highest levels of glutathione; catalase activity, and the lowest MDA levels (P = 0.0001/each). The highest anti-inflammatory activity was observed in LevAE and levZ in terms of higher inhibitory effect on IL-1β and TNF-α production (P < 0.0001 each); COX2, PGE2, and NF-κB gene expression. The three levan preparations also proved safe with no signs of toxicity, with anti-lipidemic properties as well as promising prebiotic activity that directly correlated with their antiulcer effect. This novel study highlights the implication of prebiotic-mediated systemic immunomodulation exhibited by bacterial levans that directly correlated with their gastroprotective activity.

Hibiscus-cisplatin combination treatment decreases liver toxicity in rats while increasing toxicity in lung cancer cells via oxidative stress- apoptosis pathway

Cisplatin (CIS) is a broad-spectrum anti-carcinogen that causes cytotoxic effects both in normal and cancer cells. The purpose of this study was to test whether Hibiscus sabdariffa (HS) extract can reduce CIS-induced hepatotoxicity in rodents and to assess its anticancer activity in vitro. Treatment with HS extract at daily doses of 500 mg/kg before and after a single dose of CIS (10 mg/kg) reduced hepatotoxicity in Wistar male albino rats. HS extract reduced activity of hepatic damage marker enzymes ( i.e. alanine and aspartate aminotransferases), necrosis, and apoptosis in liver tissues of CIS-treated rats. This hepatic protection was associated with reduced oxidative stress in liver tissues. The antioxidant effects of HS were manifested as a normalization of malondialdehyde levels and glutathione levels which were all raised after CIS-induction. In addition, HS treatment resulted in a decrease of catalase, and superoxide dismutase activity. The combined effects of CIS and HS were also studied in two human lung cancer cell lines (A549 and H460). Treatment with HS (20 μg /mL) enhanced the cytotoxic activity of CIS both in A549 and H460 cell lines. Interestingly, HS increased CIS-induced apoptosis and oxidative stress more clearly in A549 cells indicating that HS extract in combination with CIS could increase the efficacy of CIS in the treatment of cancer.

Production and bioactivities of nanoparticulated and ultrasonic-degraded levan generated by Erwinia tasmaniensis levansucrase in human osteosarcoma cells

Levan is a bioactive polysaccharide that can be synthesized by various microorganisms. In this study, the physicochemical properties and bioactivity of levan synthesized by recombinant levansucrase from Erwinia tasmaniensis were investigated. The synthesis conditions, including the enzyme concentration, substrate concentration, and temperature, were optimized. The obtained levan generally appeared as a cloudy suspension. However, it could transform into a hydrogel at concentrations exceeding 10 % (w/v). Then, ultrasonication was utilized to reduce the molecular weight and increase the bioavailability of levan. Dynamic light scattering (DLS) and gel permeation chromatography (GPC) indicated that the size of levan was significantly decreased by ultrasonication, whereas Fourier transform infrared spectroscopy, ¹H-nuclear magnetic resonance, and X-ray powder diffraction revealed that the chemical structure of levan was not changed. Finally, the bioactivities of both levan forms were examined using human osteosarcoma (Saos-2) cells. The result clearly illustrated that sonicated levan had higher antiproliferative activity in Saos-2 cells than original levan. Sonicated levan also activated Toll-like receptor expression at the mRNA level. These findings suggested the important beneficial applications of sonicated levan for the development of cancer therapies.

Evaluation of different bacterial honey isolates as probiotics and their efficient roles in cholesterol reduction

Continue to hypothesize that honey is a storehouse of beneficial bacteria, and the majority of these isolates are levansucrase producers. Accordingly, ten bacterial strains were isolated from different honey sources. Four honey isolates that had the highest levansucrase production and levan yield were identified by the partial sequencing of the 16S rRNA gene as Achromobacter sp. (10A), Bacillus paralicheniformis (2M), Bacillus subtilis (9A), and Bacillus paranthracis (13M). The cytotoxicity of the selected isolates showed negative blood hemolysis. Also, they are sensitive to the tested antibiotics (Amoxicillin + Flucloxacillin, Ampicillin, Gentamicin, Benzathine benzylpenicillin, Epicephin, Vancomycin, Amikacin, and Zinol). The isolates had strong alkaline stability (pHs 9, 11) and were resistant to severe acidic conditions (29-100 percent). The tested isolates recorded complete tolerance to both H₂O₂ and the bile salt (0.3% Oxgall powder) after 24 h incubation. The cell-free supernatant of the examined strains had antifungal activities against C. Albicans with varying degrees. Also, isolates 2M and 13M showed strong activities against S. aureus. The isolates showed strong adhesion and auto-aggregation capacity. Isolate 10A showed the highest antioxidant activity (91.45%) followed by 2M (47.37%). The isolates recorded different catalase and protease activity. All isolates produced cholesterol oxidase and lipase with different levels. Besides, the four isolates reduced LDL (low-density lipoprotein) to different significant values. The cholesterol-reducing ability varied not only for strains but also for the time of incubation. The previous results recommended these isolates be used safely in solving the LDL problem.

Synergistic enzyme cocktail between levansucrase and inulosucrase for superb levan-type fructooligosaccharide synthesis

Inulosucrase (ISC) and levansucrase (LSC) utilise sucrose and produce inulin- and levan-type fructans, respectively. This study aims to propose a new strategy to improve levan-type fructooligosaccharide (L-FOS) production. The effect of ISC/ LSC -mixed reaction was elucidated on L-FOS production. The presence of ISC in the LSC reaction significantly leads to the higher production of L-FOSs as the main products. Furthermore, the different ratios between ISC and LSC affected the distribution of L-FOSs. A greater amount of ISC compared to LSC promoted the synthesis of short-chain L-FOSs. Conversely, when LSC was increased, the synthesis of longer-chain L-FOSs was enhanced. The addition of trisaccharide mixtures obtained from either a single ISC or LSC reaction could enhance L-FOSs synthesis in the LSC reaction. Analysis of these trisaccharides revealed that most species of the oligosaccharides were similar, with 1-kestose being the major one. The supplement of only 1-kestose in the LSC reaction showed similar results to those of the reaction in the presence of trisaccharide mixtures. Moreover, the results were supported by molecular dynamics simulations. This work not only provides an improvement in L-FOS production but also revealed and supported some insights into the mechanism of fructansucrases.

Optimization strategy of Bacillus subtilis MT453867 levansucrase and evaluation of levan role in pancreatic cancer treatment

Pancreatic cancer is the fourth most lethal cancer type worldwide. Due to multiple levan applications including anticancer activities, studies related to levansucrase production are of interest. To our knowledge, levan effect on pancreatic cancer cells has not been tested previously. In this work, among eighteen bacterial honey isolates, Bacillus subtilis MT453867 showed the highest levan yield (33 g/L) and levansucrase production (8.31 U/mL). One-factor-at-a-time technique increased levansucrase activity by 60% when MgSO₄ was eliminated. The addition of 60 g/L banana peels enhanced the enzyme activity (192 U/mL). Placket Burman design determined the media composition for maximum levan yield (54.8 g/L) and levansucrase production (505 U/mL). The identification of levan was confirmed by thin-layer chromatography, Fourier-Transform Infrared spectrometric analysis, ¹³C-nuclear-magnetic resonance, and ¹H-nuclear-magnetic resonance. Both crude and dialyzed levan completely inhibited the pancreatic cancer cell line at 100 ppm with no cytotoxicity on the normal retinal cell line. The LD₅₀ of crude levan was 4833 mg/kg body weight. Levan had strong antioxidant activity and significantly reduced the expression of CXCR4 and MCM7 genes in pancreatic cancer cells with significant DNA fragmentation. In conclusion, Bacillus subtilis MT453867 levan is a promising adjunct to pancreatic-anticancer agents with both anti-cancer and chemoprotective effects.