Due to the emergence of multi-drug resistant strains, development of novel antibiotics has become a critical issue. One promising approach is the use of transition metals, since they exhibit rapid ...and significant toxicity, at low concentrations, in prokaryotic cells. Nevertheless, one main drawback of transition metals is their toxicity in eukaryotic cells. Here, we show that the barriers to use them as therapeutic agents could be mitigated by combining them with silver. We demonstrate that synergism of combinatorial treatments (Silver/transition metals, including Zn, Co, Cd, Ni, and Cu) increases up to 8-fold their antimicrobial effect, when compared to their individual effects, against E. coli and B. subtilis. We find that most combinatorial treatments exhibit synergistic antimicrobial effects at low/non-toxic concentrations to human keratinocyte cells, blast and melanoma rat cell lines. Moreover, we show that silver/(Cu, Ni, and Zn) increase prokaryotic cell permeability at sub-inhibitory concentrations, demonstrating this to be a possible mechanism of the synergistic behavior. Together, these results suggest that these combinatorial treatments will play an important role in the future development of antimicrobial agents and treatments against infections. In specific, the cytotoxicity experiments show that the combinations have great potential in the treatment of topical infections.
The Trichomonas vaginalis 120 kDa protein adhesin (AP120) is induced under iron-rich conditions and has sequence homology with pyruvate:ferredoxin oxidoreductase A (PFO A), a hydrogenosomal enzyme ...that is absent in humans. This homology raises the possibility that, like AP120, PFO might be localized to the parasite surface and participate in cytoadherence. Here, the cellular localization and function of PFO that was expressed under various iron concentrations was investigated using a polyclonal antibody generated against the 50 kDa recombinant C-terminal region of PFO A (anti-PFO50). In Western blot assays, this antibody recognized a 120 kDa protein band in total protein extracts, and proteins with affinity to the surface of HeLa cells from parasites grown under iron-rich conditions. In addition to localization that is typical of hydrogenosomal proteins, PFOs that were expressed under iron-rich conditions were found to localize at the surface. This localization was demonstrated using immunofluorescence and co-localization assays, as well as immunogold transmission electron microscopy. In addition to describing its enzyme activity, we describe a novel function in trichomonal host interaction for the PFO localized on the parasite surface. The anti-PFO50 antibody reduced the levels of T. vaginalis adherence to HeLa cell monolayers in a concentration-dependent manner. Thus, T. vaginalis PFO is an example of a surface-associated cell-binding protein that lacks enzyme activity and that is involved in cytoadherence. Additionally, PFO behaves like AP120 in parasites grown under iron-rich conditions. Therefore, these data suggest that AP120 and PFO A are encoded by the same gene, namely pfo a.
In this work, complete elimination of Escherichia coli and Salmonella typhimurium was achieved in 120 min using a heterogeneous photo-Fenton process under sunlight at pH 6.5 in distilled water. A ...face-centered composite central design 22 with one categoric factor and three replicates at the central point was used to evaluate the effect of iron (III) oxide concentration (0.8–3.4 mg L−1), H2O2 (2–10 mg L−1), and the type of iron oxide phase (maghemite and hematite) on the inactivation of both bacteria. The results showed that the amount of catalyst, H2O2 concentration and their interaction were significant factors (p < 0.05) in the elimination of the microorganisms. Thus, under the best conditions (3.4 mg L−1 of iron (III) oxide and 10 mg L−1 of H2O2) in the experimental ranges, complete inactivation of E. coli and S. typhimurium was achieved (6-log reduction) in 120 min using the photo-Fenton treatment with both iron-oxide phases. Furthermore, the photocatalytic elimination of both bacteria by the photo-Fenton process using hematite and maghemite in secondary-treated wastewater effluent was performed obtaining slower inactivation rates (1.2–5.9 times) than in distilled water due to the matrix effect of the effluent from a wastewater treatment plant. Nevertheless, the process continued to be effective in the effluent, achieving complete bacterial elimination in 150 min using the hematite phase. Additionally, the SEM images of the bacterial cells showed that the heterogeneous photo-Fenton treatment generated permanent and irreversible cell damage, resulting in complete cell death.
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•E. coli and S. typhimurium were eliminated in 120 min by a photo-Fenton process at near-neutral pH.•The amount of Fe3+ and H2O2 were significant variables in bacterial elimination.•The hematite phase was effective in the disinfection of water from WWTP effluent.•SEM images revealed extensive cell damage caused by the photo-Fenton process.•Photo-Fenton treatment prevented bacterial regrowth.
Tilia americana var. mexicana (T. americana) is a plant widely used in Mexico for its medicinal properties on the central nervous system. In the present study, we designed a protocol to investigate ...the neuroprotective effects of non-polar and polar extracts of T. americana on damage induced by cerebral ischaemia in mice. Vehicle or extracts were administered immediately after ischaemia. Functional neurological deficit, survival percentage and infarct area were determined in each experimental group. Results showed that groups treated with non-polar or polar extracts of T. americana had increased survival rate, improved neurological deficits and diminished the infarct area in relation to the ischaemic group. In conclusion, this study confirms the neuroprotective activity of T. americana, suggests a possible synergism between non-polar and polar constituents and supports its potential as a useful aid in the clinical management of stroke.
Finding novel antibiotics and antimicrobial materials has become of great importance to modern society due to the alarming increase in the development of multidrug resistance in various bacterial ...strains. This problem is even more complex when infections involve bacterial strains in stationary metabolic states, since most of the antibiotics found in the market do not have an effect on bacteria in dormant metabolic states. A promising field to aid in the solution of this problem is nanotechnology, since it offers a wide avenue for the development of potential therapeutics, specifically the use of silver metal nanoparticles. Silver nanoparticles have proven to be highly effective antimicrobial agents and excellent candidates to be engineered and designed into clever delivery systems, taking advantage of their rapid and potent toxicity on prokaryotic cells at low concentrations. Metal nanoparticles are most commonly synthetized through one or a series of redox chemical reactions using powerful but environmentally toxic-reducing agents. Therefore, in this work, we propose a biosynthesis method that allows the production of nanoparticles, with homogenous shapes and narrow size distributions, through an environmentally friendly technique that does not produce toxic residues. Here, silver nanoparticles were produced from silver salt (AgNO3) using three different growth culture media residues from E. coli top 10. The three different culture media residues used included LB, LBN, and LBE; all of them displaying a different chemical and nutrient composition. Here, after characterization of the different silver nanoparticles produced with the different media, we demonstrated that the LB culture-conditioned media was the most suitable to produce them since they displayed the most narrow size distribution, with an average 10.6 nm in diameter, a relatively low standard deviation of 5.5 nm, and a narrow UV-vis spectrum absorption peak at 420 nm. The other methods presented larger nanoparticle sizes and broader size distributions. Furthermore, nanoparticles produced with LB Lennox were found to be, at very low concentrations, effective antimicrobial agent against E. coli top 10 at stationary phase. Therefore, these results seem to contribute knowledge linked to the production of antimicrobial nanoparticles (Ag-NPs) through green synthesis and represent a platform to treat infections caused by nongrowing bacteria.
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•Trichomonas vaginalis cathepsin D-like aspartic proteinase (Tv-CatD) belongs to the pepsin family A1 of clan AA.•Tv-CatD is up-regulated by glucose.•Tv-CatD has multiple ...localizations: in vesicles and lysosomes, the Golgi complex, endoplasmic reticulum, and nucleus.•Tv-CatD degrades human hemoglobin.
Trichomonas vaginalis genome encodes ∼440 proteases, six of which are aspartic proteases (APs). However, only one belongs to a clan AA (EC 3.4.23.5), family A1 (pepsin A), cathepsin D-like protease. This AP is encoded by an 1113-bp gene (tv-catd), which translates into a 370-aa residues zymogen of 40.7-kDa and a theoretical pI of 4.6, generating a ∼35 kDa active enzyme after maturation (Tv-CatD). The goal of this study was to identify and analyze the effect of glucose on the expression of Tv-CatD at the transcript and protein levels, subcellular localization, and proteolytic activity. The qRT-PCR assays showed a ∼2-fold increase in tv-catd mRNA under high-glucose (HG) conditions compared to glucose-restriction (GR) conditions. We amplified, cloned, and expressed the tv-catd gene, and purified the recombinant precursor enzyme (Tv-CatDr) to generate a polyclonal antibody (anti-Tv-CatDr). Western blot (WB) and immunolocalization assays showed that glucose increases the amount of Tv-CatD in different subcellular localizations and in in vitro secretions. Additionally, Tv-CatD proteolytic activity was detected in protease-resistant extracts (PREs) using a synthetic fluorogenic peptide specific for cathepsin D/E APs at different pHs and in the presence of AP inhibitors. In a two-dimensional (2-DE) WB analysis of a PRE from parasites grown under GR and HG conditions, an anti-Tv-CatDr antibody detected a 35-kDa protein spot at pI 5.0 identified as the mature Tv-CatD form by mass spectrometry that showed proteolytic activity in 2-DE zymograms copolymerized with hemoglobin under both glucose conditions. Thus, Tv-CatD could be involved in trichomonal hemolysis.
The capacity of Cladosporium cladosporioides biomass for removal of Cr(VI) in aqueous solutions was evaluated. A 2 × 2 factorial experiment design was used to study the effects of pH and biomass ...doses. Lower pH values and larger biomass doses increased the capacity of C. cladosporioides biomass for removal of Cr(VI), reaching a reduction capacity of 492.85 mg g
, a significantly higher value compared to other biomass reported. Cr(VI) removal kinetic rates followed a pseudo-second order model, like other fungal biomass reported previously. The apparent adsorption process was described well by the Freundlich isothermal model. However, determination of total chromium indicated that adsorption of Cr(VI) was followed by a redox reaction that released proportional quantities of Cr(III) into the experimental supernatant, suggesting a parallel adsorption-reduction process. Comparison of Fourier transform infrared spectroscopy spectra of C. cladosporioides biomass before and after the reduction process demonstrated the involvement of positively charged amino groups in the Cr(VI) adsorption-reduction process.
There is a current need to develop low-cost strategies to degrade and eliminate industrially used colorants discharged into the environment. Colorants discharged into natural water streams pose ...various threats, including: toxicity, degradation of aesthetics and inhibiting sunlight penetration into aquatic ecosystems. Dyes and colorants usually have complex aromatic molecular structures, which make them very stable and difficult to degrade and eliminate by conventional water treatment systems. The results in this work demonstrated that heavy metal-resistant Rhodotorula mucilaginosa strain UANL-001L isolated from the northeast region of Mexico produce an exopolysaccharide (EPS), during growth, which has colorant adsorption potential. The EPS produced was purified by precipitation and dialysis and was then physically and chemically characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and chemical elemental analysis. Here, the ability of the purified EPS produced to adsorb methylene blue (MB), which served as a model colorant, is studied. MB adsorption by the EPS is found to follow Langmuir Adsorption Isotherm kinetics at 25°C. Further, by calculating the Langmuir constant the adsorption capabilities of the EPS produced by the Rhodotorula mucilaginosa strain UANL-001L is compared to that of other adsorbents, both, microbially produced and from agroindustrial waste. The total adsorption capacity of the EPS, from the Rhodotorula mucilaginosa strain UANL-001L, was found to be two-fold greater than the best bioadsorbents reported in the literature. Finally, apart from determining which heavy metals stimulated EPS production in the strain, the optimal conditions of pH, heavy metal concentration, and rate of agitation of the growing culture for EPS production, was determined. The EPS reported here has the potential of aiding in the efficient removal of colorants both in water treatment plants and in situ in natural water streams.
Colorrectal Kaposi's sarcoma Soler-Humanes, Rocío; Lobato-Bancalero, Luis Alonso; Sanchiz-Cárdenas, Elena ...
Revista española de enfermedades digestivas
106, Številka:
3
Journal Article
PDF
