A review of the pharmacological applications of lignins provides evidence of their protective role against the development of different diseases. In many cases, the effects of lignins could be ...explained by their antioxidant capacity. Here, we present a systematic review of the literature from the period 2010-2016 which provides information concerning new applications of lignins derived from recent research. The most promising findings are reported, including the methodologies employed and results obtained with lignins or their derivatives which may improve human health. We highlight potential applications in the treatment of obesity, diabetes, thrombosis, viral infections and cancer. Moreover, we report both that lignins can be used in the preparation of nanoparticles to deliver different drugs and also their use in photoprotection.
Nanoparticles have received much attention recently due to their use in cancer therapy. Studies have shown that different metal oxide nanoparticles induce cytotoxicity in cancer cells, but not in ...normal cells. In some cases, such anticancer activity has been demonstrated to hold for the nanoparticle alone or in combination with different therapies, such as photocatalytic therapy or some anticancer drugs. Zinc oxide nanoparticles have been shown to have this activity alone or when loaded with an anticancer drug, such as doxorubicin. Other nanoparticles that show cytotoxic effects on cancer cells include cobalt oxide, iron oxide and copper oxide. The antitumor mechanism could work through the generation of reactive oxygen species or apoptosis and necrosis, among other possibilities. Here, we review the most significant antitumor results obtained with different metal oxide nanoparticles.
Sinorhizobium (Ensifer) fredii (S. fredii) is a rhizobial species exhibiting a remarkably broad nodulation host-range. Thus, S. fredii is able to effectively nodulate dozens of different legumes, ...including plants forming determinate nodules, such as the important crops soybean and cowpea, and plants forming indeterminate nodules, such as Glycyrrhiza uralensis and pigeon-pea. This capacity of adaptation to different symbioses makes the study of the molecular signals produced by S. fredii strains of increasing interest since it allows the analysis of their symbiotic role in different types of nodule. In this review, we analyze in depth different S. fredii molecules that act as signals in symbiosis, including nodulation factors, different surface polysaccharides (exopolysaccharides, lipopolysaccharides, cyclic glucans, and K-antigen capsular polysaccharides), and effectors delivered to the interior of the host cells through a symbiotic type 3 secretion system.
Abstract Nanoparticles with pH-sensitive behavior may enhance the success of chemotherapy in many cancers by efficient intracellular drug delivery. Here, we investigated the effect of a bioactive ...surfactant with pH-sensitive properties on the antitumor activity and intracellular behavior of methotrexate-loaded chitosan nanoparticles (MTX–CS–NPs). NPs were prepared using a modified ionotropic complexation process, in which was included the surfactant derived from Nα ,Nϵ -dioctanoyl lysine with an inorganic lithium counterion. The pH-sensitive behavior of NPs allowed accelerated release of MTX in an acidic medium, as well as membrane-lytic pH-dependent activity, which facilitated the cytosolic delivery of endocytosed materials. Moreover, our results clearly proved that MTX–CS–NPs were more active against the tumor HeLa and MCF-7 cell lines than the free drug. The feasibilty of using NPs to target acidic tumor extracellular pH was also shown, as cytotoxicity against cancer cells was greater in a mildly acidic environment. Finally, the combined physicochemical and pH-sensitive properties of NPs generally allowed the entrapped drug to induce greater cell cycle arrest and apoptotic effects. Therefore, our overall results suggest that pH-sensitive MTX–CS–NPs could be potentially useful as a carrier system for tumor and intracellular drug delivery in cancer therapy.
Reversible phosphorylation is a key mechanism that regulates many cellular processes in prokaryotes and eukaryotes. In prokaryotes, signal transduction includes two-component signaling systems, which ...involve a membrane sensor histidine kinase and a cognate DNA-binding response regulator. Several recent studies indicate that alternative regulatory pathways controlled by Hanks-type serine/threonine kinases (STKs) and serine/threonine phosphatases (STPs) also play an essential role in regulation of many different processes in bacteria, such as growth and cell division, cell wall biosynthesis, sporulation, biofilm formation, stress response, metabolic and developmental processes, as well as interactions (either pathogenic or symbiotic) with higher host organisms. Since these enzymes are not DNA-binding proteins, they exert the regulatory role via post-translational modifications of their protein targets. In this review, we summarize the current knowledge of STKs and STPs, and discuss how these enzymes mediate gene expression in prokaryotes. Many studies indicate that regulatory systems based on Hanks-type STKs and STPs play an essential role in the regulation of various cellular processes, by reversibly phosphorylating many protein targets, among them several regulatory proteins of other signaling cascades. These data show high complexity of bacterial regulatory network, in which the crosstalk between STK/STP signaling enzymes, components of TCSs, and the translational machinery occurs. In this regulation, the STK/STP systems have been proved to play important roles.
The potential antioxidant activity of industrial lignins obtained from different sources and their potential cytotoxic effect on two immortalized cell lines is studied. In addition the stability of ...aqueous preparations of these lignins is studied together with the effect on them of ultraviolet irradiation. The lignins studied show a high antioxidant capacity over a range of concentrations that are not harmful to normal human cells. The stability of the lignin solutions when they are exposed to UVA light is confirmed. These findings suggest new uses for lignins in cosmetic and topical medical formulations. This study aims to demonstrate the antioxidant activity and stability of several lignins from different sources. It assesses their suitability for new commercial applications, mainly in cosmetics and pharmaceuticals, by discarding any possible cytotoxic properties.
Summary
Sinorhizobium fredii HH103 RifR is a broad host‐range rhizobial strain able to nodulate with soybean and Lotus burttii, but it is ineffective with L. japonicus. Here, we study the role of the ...HH103 RifR SyrM protein in the regulation of gene expression and its relevance in symbiosis with those three legumes. RNAseq analyses show that HH103 SyrM is an important transcriptional regulator not only in the presence of inducer flavonoids but also in its absence. Lack of SyrM increases Nod factors production and decreases genistein‐mediated repression of exopolysaccharide production in HH103. In symbiosis, mutation of syrM partially impaired interaction with soybean but improves effectiveness with L. burttii and extends the host‐rage to L. japonicus Gifu. In addition, HH103 syrM mutants enter in both Lotus species by infection threads, whereas HH103 uses the more primitive intercellular infection to enter into L. burttii roots These symbiotic phenotypes were previously observed in two other HH103 mutants affected in symbiotic regulators, nodD2 and nolR, revealing that in S. fredii HH103 numerous transcriptional regulators finely modulate symbiotic gene expression.
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