Natural flavonoids for the prevention of colon cancer: A comprehensive review of preclinical and clinical studies

Flavonoids comprise a group of natural polyphenols consisting of more than 5,000 subtypes mostly existing in fruits and vegetables. Flavonoids consumption could potentially attenuate the incidence and recurrence risk of colorectal cancers through their antiperoxidative, antioxidant, and anti-inflammatory effects. In addition, these compounds regulate the mitochondrial function, balance the bacterial flora and promote the apoptosis process in cancerous cells. However, some previous data failed to show the effectiveness of flavonoids in reducing the risk of colorectal cancer. In this study, we have reviewed the efficacy of different flavonoids subtypes on the risk of colon cancer and molecular mechanisms involved in this process in both clinical and animal studies. In addition, we tried to elucidate the potential synergy between these compounds and current colorectal cancer treatments.     

Distribution of pathogenicity island markers and virulence factors in new phylogenetic groups of uropathogenic <Emphasis Type="Italic">Escherichia coli</Emphasis> isolates

The present study was aimed at investigating the relationship between the new Clermont’s phylogenetic groups, virulence factors, and pathogenicity island markers (PAIs) among uropathogenic Escherichia coli (UPEC) in Iran. This cross-sectional study was carried out on 140 UPEC isolates collected from patients with urinary tract infections in Bushehr, Iran. All isolates were subjected to phylogenetic typing using a new quadruplex-PCR method. The presence of PAI markers and virulence factors in UPEC strains was evaluated by multiplex PCR. The most predominant virulence gene was fimH (85%), followed by iucC (61.4%), papC (38.6%), hlyA (22.1%), cnf-1 (18.6%), afa (10.7%), papG and neuC (each 9.3%), ibeA (3.6%), and sfa/foc (0.7%). The most common phylogenetic group was related to B2 (39.3%), and the least common to A (0.7%). The most prevalent PAI marker was PAI IV536 (77.14%), while markers for PAI III536 (13.57%), PAI IIJ96 (12.86%), and PAI II536 (12.14%) were the least frequent among the UPEC strains. Meanwhile, the PAI IJ96 marker was not detected. There was a significant association between the phylogenetic group B2 and all the studied virulence genes and PAI markers. To our knowledge, this is the first study to compare the relationship between new phylogenetic groups, virulence genes and PAI markers in UPEC strains in Iran. The phylogenetic group B2 was predominantly represented among the studied virulence genes and PAI markers, indicating the preference of particular strains to carry virulence genes.     

Building and deploying a cyberinfrastructure for the data-driven design of chemical systems and the exploration of chemical space

Abstract

The use of modern data science has recently emerged as a promising new path to tackling the complex challenges involved in the creation of next-generation chemistry and materials. However, despite the appeal of this potentially transformative development, the chemistry community has yet to incorporate it as a central tool in every-day work. Our research program is designed to enable and advance this emerging research approach. It is centred around the creation of a software ecosystem that brings together physics-based modelling, high-throughput in silico screening and data analytics (i.e. the use of machine learning and informatics for the validation, mining and modelling of chemical data). This cyberinfrastructure is devised to offer a comprehensive set of data science techniques and tools as well as a general-purpose scope to make it as versatile and widely applicable as possible. It also emphasises user-friendliness to make it accessible to the community at large. It thus provides the means for the large-scale exploration of chemical space and for a better understanding of the hidden mechanisms that determine the properties of complex chemical systems. Such insights can dramatically accelerate, streamline and ultimately transform the way chemical research is conducted. Aside from serving as a production-level tool, our cyberinfrastructure is also designed to facilitate and assess methodological innovation. Both the software and method development work are driven by concrete molecular design problems, which also allow us to assess the efficacy of the overall cyberinfrastructure.     

How Methylammonium Cations and Chlorine Dopants Heal Defects in Lead Iodide Perovskites

Lead tri‐iodide methylammonium (MAPbI₃) perovskite polycrystalline materials show complex optoelectronic behavior, largely because their 3D semiconducting inorganic framework is strongly perturbed by the organic cations and ubiquitous structural or chemical inhomogeneities. Here, a newly developed time‐dependent density functional theory‐based theoretical formalism is taken advantage of. It treats electron–hole and electron–nuclei interactions on the same footing to assess the many‐body excited states of MAPbI₃ perovskites in their pristine state and in the presence of point chemical defects. It is shown that lead and iodine vacancies yield deep trap states that can be healed by dynamic effects, namely rotation of the methylammonium cations in response to point charges, or through slight changes in chemical composition, namely by introducing a tiny amount of chlorine dopants in the defective MAPbI₃. The theoretical results are supported by photoluminescence experiments on MAPbI_3?mCl_m and pave the way toward the design of defect‐free perovskite materials with optoelectronic performance approaching the theoretical limits.     

A Recombinant Probiotic, <Emphasis Type="Italic">Lactobacillus casei,</Emphasis> Expressing the <Emphasis Type="Italic">Clostridium perfringens</Emphasis> α-toxoid,as an Orally Vaccine Candidate Against Gas Gangrene and Necrotic Enteritis

The alpha-toxin is one of the virulence factors of Clostridium perfringens for gas gangrene in humans and animals or necrotic enteritis in poultry. The C-terminal domain of this toxin ( cpa _247-370 ) was synthesized and cloned into pT1NX vector to construct the pT1NX-alpha plasmid. This surface-expressing plasmid was electroporated into Lactobacillus casei ATCC 393, generating the recombinant L. casei strain expressing alpha-toxoid (LC-α strain). Expression of this modified alpha-toxoid was confirmed by SDS-PAGE, immunoblotting, and direct immunofluorescence microscopy. BALB/c mice, immunized orally by the recombinant LC-α strain, elicited mucosal and significantly humoral immune responses (p < 0.05) and developed a protection against 900 MLD/mL of the standard alpha-toxin. This study showed that this recombinant LC-α strain could be a promising vaccine candidate against gas gangrene and necrotic enteritis.     

Turnover of Phospholipids in an Unsaturated Fatty Acid Auxotroph of Escherichia coli

The membrane phospholipids of an unsaturated fatty acid auxotroph of Escherichia coli were found to undergo turnover. These phospholipids were excreted into the culture medium, and were replaced in the cell with newly synthesized phospholipids. Phospholipids of growing cells supplemented with elaidic acid underwent rapid turnover, while those of cells supplemented with oleate, or cis-vaccenate plus palmitoleate, underwent slow turnover. Starvation for required amino acids stimulated this turnover in the latter two cases. Protein was also lost from growing cells. However, after amino acid starvation this loss ceased while phospholipid turnover continued. Electron micrographs of growing cells indicated that large pieces of membrane-like material were separating from the cell surface.