Comparative genomic analysis of Pseudomonas aeruginosa strains susceptible and resistant to carbapenems and aztreonam isolated from patients with healthcare-associated infections in a Mexican hospital.

Pseudomonas aeruginosa (PA) is an important opportunistic pathogen that causes different infections on immunocompromised patients. Within PA accessory genome, differences in virulence, antibiotic resistance and biofilm formation have been described between strains, leading to the emergence of multidrug-resistant strains. The genome sequences of 17 strains isolated from patients with healthcare-associated infections in a Mexican hospital were genomically and phylogenetically analyzed and antibiotic resistance genes, virulence genes, and biofilm formation genes were detected. Fifteen of the 17 strains were resistant to at least two of the carbapenems meropenem, imipenem, and the monobactam aztreonam. The antibiotic resistance (mexA, mexB, and oprM) and the biofilm formation (pslA and pslD) genes were detected in all strains. Differences were found between strains in accessory genome size. The strains had different sequence types, and seven strains had sequence types associated with global high risk epidemic PA clones. All strains were represented in two groups among PA global strains. In the 17 strains, horizontally acquired resistance genes to aminoglycosides and beta-lactams were found, mainly, and between 230 and 240 genes that encode virulence factors. The strains under study were variable in terms of their accessory genome, antibiotic resistance, and virulence genes. With these characteristics, we provide information about the genomic diversity of clinically relevant PA strains.

Optimizing Decellularization of Bovine Ovarian Tissue: Toward a Transplantable Artificial Ovary Scaffold with Minimized Residual Toxicity and Preserved Extracellular Matrix Morphology.

INTRODUCTION: The decellularized extracellular matrix (dECM) from ovarian tissue could be the best scaffold for the development of a transplantable artificial ovary. Typically, dECM from ovarian tissue has been obtained using sodium dodecyl sulfate (SDS), at a concentration of 1% for 24 h. However, SDS can leave residues in the tissue, which may be toxic to the seeded cells. This study aimed to obtain dECM from bovine ovarian tissue using SDS and NaOH at a minimum concentration in the shortest incubation time. METHODS: The respective SDS and NaOH concentrations investigated were 1% and 0.2M; 0.5% and 0.1M; 0.1% and 0.02M, and 0.05% and 0.01M, with 24, 12, and 6 h incubation periods. After the incubation time the tissue was washed in 50 mL of distilled water for 6 h. RESULTS: Histological analysis confirmed decellularization and showed the conservation of collagen fibers in all samples following treatment. Furthermore, the lowest SDS and NaOH concentrations that showed no DNA remaining during electrophoresis analysis were 0.1% and 0.02M when incubated for 24 and 12 h. DNA quantification resulted in ˂ 0.2 ng DNA/mg ovarian tissue using these protocols. Additionally, the coculture of dECM (obtained by 0.1% SDS and 0.02M NaOH for 12 h) with ovarian cells showed that there was no toxic effect for the cells for up to 72 h. CONCLUSION: The protocol involving 0.1% SDS and 0.02M NaOH for 12 h incubation decellularizes bovine ovarian tissue, generating a dECM that preserves the native ECM morphology and is non-toxic to ovarian cells.

Main Group Molecular Switches with Swivel Bifurcated to Trifurcated Hydrogen Bond Mode of Action.

Artificial molecular machines have captured the full attention of the scientific community since Jean-Pierre Sauvage, Fraser Stoddart, and Ben Feringa were awarded the 2016 Nobel Prize in Chemistry. The past and current developments in molecular machinery (rotaxanes, rotors, and switches) primarily rely on organic-based compounds as molecular building blocks for their assembly and future development. In contrast, the main group chemical space has not been traditionally part of the molecular machine domain. The oxidation states and valency ranges within the p-block provide a tremendous wealth of structures with various chemical properties. Such chemical diversity─when implemented in molecular machines─could become a transformative force in the field. Within this context, we have rationally designed a series of NH-bridged acyclic dimeric cyclodiphosphazane species, [(µ-NH){PE(µ-NtBu)2PE(NHtBu)}2] (E = O and S), bis-PV2N2, displaying bimodal bifurcated R21(8) and trifurcated R31(8,8) hydrogen bonding motifs. The reported species reversibly switch their topological arrangement in the presence and absence of anions. Our results underscore these species as versatile building blocks for molecular machines and switches, as well as supramolecular chemistry and crystal engineering based on cyclophosphazane frameworks.

Mechanosynthesis and photophysics of colour-tunable photoluminescent group 13 metal complexes with sterically demanding salen and salophen ligands.

A series of four photoluminescent Al and In complexes were synthesised using an environmentally-benign mechanosynthesis strategy. Sterically crowded 3,5-di-tert-butyl functionalised salophen and salen ligands and their respective complexes have been synthesised in the solid-state and fully characterised. Subsequent photophysics and electrochemistry studies of the resulting complexes suggest that these new group 13 complexes can be viable alternatives to traditional photoluminescent complexes based on expensive and low abundant noble metals. The herein-reported strategy avoids the use of organic solvents and provides a process with low environmental impact and enhanced energy efficiency.

Preparation, Aromaticity, and Bromination of Spiro Iridafurans.

Iridium centers of [Ir(µ-Cl)(C8H14)2]2 (1) activate the Cß(sp2)-H bond of benzylideneacetone to give [Ir(µ-Cl){κ2-C,O-[C(Ph)CHC(Me)O]}2]2 (2), which is the starting point for the preparation of the spiro iridafurans IrCl{κ2-C,O-[C(Ph)CHC(Me)O]}2(PiPr3) (3), [Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2(MeCN)2]BF4 (4), [Ir(µ-OH){κ2-C,O-[C(Ph)CHC(Me)O]}2]2 (5), Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2{κ2-C,N-[C6MeH3-py]} (6), and Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2{κ2-O,O-[acac]} (7). The five-membered rings are orthogonally arranged with the oxygen atoms in trans in an octahedral environment of the iridium atom. Spiro iridafurans are aromatic. The degree of aromaticity and the negative charge of the CH-carbon of the rings depend on ligand trans to the carbon directly attached to the metal. Aromaticity has been experimentally confirmed by bromination of iridafurans with N-bromosuccinimide (NBS). Reactions are sensitive to the degree of aromaticity of the ring and the negative charge of the attacked CH-carbon. Iridafurans can be selectively brominated, when different ligands lie trans to metalated carbons. Bromination of 3 occurs in the ring with the metalated carbon trans to chloride, whereas the bromination of 6 takes place in the ring with the metalated carbon trans to pyridyl. The first gives IrCl{κ2-C,O-[C(Ph)CBrC(Me)O]}{κ2-C,O-[C(Ph)CHC(Me)O]}(PiPr3) (8), which reacts with more NBS to form IrCl{κ2-C,O-[C(Ph)CBrC(Me)O]}2(PiPr3) (9). The second yields Ir{κ2-C,O-[C(Ph)CBrC(Me)O]}{κ2-C,O-[C(Ph)CHC(Me)O]}{κ2-C,N-[C6MeH3-py]} (10). The origin of the selectivity is kinetic, with the rate-determining step of the reaction being the NBS attack. The activation energy depends on the negative charge of the attacked atom; a higher negative charge allows for a lower activation energy. Accordingly, complex 7 undergoes bromination in the acetylacetonate ligand, giving Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2{κ2-O,O-[acacBr]} (11).

Transcriptomic analysis of bell pepper (Capsicum annuum L.) revealing key mechanisms in response to low temperature stress.

BACKGROUND: Bell pepper (Capsicum annuum L.) is one of the most economically and nutritionally important vegetables worldwide. However, its production can be affected by various abiotic stresses, such as low temperature. This causes various biochemical, morphological and molecular changes affecting membrane lipid composition, photosynthetic pigments, accumulation of free sugars and proline, secondary metabolism, as well as a change in gene expression. However, the mechanism of molecular response to this type of stress has not yet been elucidated. METHODS AND RESULTS: To further investigate the response mechanism to this abiotic stress, we performed an RNA-Seq transcriptomic analysis to obtain the transcriptomic profile of Capsicum annuum exposed to low temperature stress, where libraries were constructed from reads of control and low temperature stress samples, varying on average per treatment from 22,952,190.5-27,305,327 paired reads ranging in size from 30 to 150 bp. The number of differentially expressed genes (DEGs) for each treatment was 388, 417 and 664 at T-17 h, T-22 h and T-41 h, respectively, identifying 58 up-regulated genes and 169 down-regulated genes shared among the three exposure times. Likewise, 23 DEGs encoding TFs were identified at T-17 h, 30 DEGs at T-22 h and 47 DEGs at T-42 h, respectively. GO analysis revealed that DEGs were involved in catalytic activity, response to temperature stimulus, oxidoreductase activity, stress response, phosphate ion transport and response to abscisic acid. KEGG pathway analysis identified that DEGs were related to flavonoid biosynthesis, alkaloid biosynthesis and plant circadian rhythm pathways in the case of up-regulated genes, while in the case of down-regulated genes, they pertained to MAPK signaling and plant hormone signal transduction pathways, present at all the three time points of low temperature exposure. Validation of the transcriptomic method was performed by evaluation of five DEGs by quantitative polymerase chain reaction (q-PCR). CONCLUSIONS: The data obtained in the present study provide new insights into the transcriptome profiles of Capsicum annuum stem in response to low temperature stress. The data generated may be useful for the identification of key candidate genes and molecular mechanisms involved in response to this type of stress.

First Confirmed Report of Rhizoctonia solani AG-7 Causing Potato Stem Canker in Mexico.

Rhizoctonia solani, is the causal agent of black scurf and stem canker of potatoes (Solanum tuberosum L.) throughout the world. In November 2021, stem canker symptoms were observed in two potato fields located in Ahome, Sinaloa, Mexico. The disease incidence was estimated up to 15%. For fungal isolation, fragments of symptomatic stems were surface sterilized with 2% sodium hypochlorite for 2 min, rinsed with sterilized distilled water, and blotted dry on sterile filter paper. Fragments were placed on PDA medium and incubated at 25°C in darkness for 4 days. Rhizoctonia-like colonies were consistently obtained and 12 isolates were purified by the hyphal-tip method. Fungal colonies on PDA were white initially and then turned brown, raised, and with entire or undulate edges. Septate hyphae were hyaline, smooth, and branched at right angles with a septum near the point of branching. Microscopic examination by staining with 1% safranin O and 3% KOH solution showed multinucleate cells. The morphological features of the isolates resembled those of Rhizoctonia solani (Sneh et al. 1991). Four representative isolates were selected for molecular analysis and pathogenicity tests. The isolates were deposited in the Culture Collection of Phytopathogenic Fungi at the Research Center for Food and Development (Culiacán, Sinaloa) under accession nos. CCLF267, CCLF274, CCLF277, and CCLF279. For molecular identification, genomic DNA from each of the four isolates was extracted, and the internal transcribed spacer (ITS) region was amplified, and sequenced with the primer pair ITS5/ITS4 (White et al. 1990). The sequences were deposited in GenBank (accession nos. OP784258 to OP784261). Phylogenetic analyses were performed using the Maximum Likelihood method with ITS sequences for anastomosis groups (AG) of Rhizoctonia solani. The phylogenetic tree grouped the four isolates within the R. solani AG-7 clade with high bootstrap support (100%). For pathogenicity tests, certified pathogen-free potato mini-tuber (cv. Fianna) were placed in a polystyrene pot (1 L) filled with a 5 cm layer of a sterile substrate composed of soil and peat moss (2:1 w/w). One rice grain (20 mg) colonized with each isolate was placed 10 mm above the uppermost sprout tip and covered with the sterile substrate (Inokuti et al. 2019). Control plants were inoculated with sterile rice grains. All pots were transferred to a greenhouse where the temperature ranged from 20 to 32°C. Stem necrosis symptoms were observed on all inoculated plants 25 days after emergence, whereas control plants remained symptomless. Pathogenicity test was performed twice with similar results. Fungi were reisolated from the infected stems and found to be morphologically identical to the isolates used for inoculation, thus fulfilling Koch's postulates. The AG-7 has been previously reported to cause potato diseases in South Africa (Truter and Wehner 2004). In Mexico, Carling et al. (1998) reported the presence of an isolate of R. solani AG-7 obtained from a potato tuber-borne sclerotium in Toluca; however, there is no information about the methodology used for the characterization of that isolate. To our knowledge, this is the first confirmed report of R. solani AG-7 causing potato stem canker in Mexico. Our findings improve knowledge about R. solani AGs occurring in potato fields in Mexico. So, further studies should be conducted to investigate the diversity, prevalence, and fungicide sensitivity of AGs distributed in the main potato-producing states in Mexico.

Cytoskeletal proteins: lessons learned from bacteria.

Cytoskeletal proteins are classified as a group that is defined functionally, whose members are capable of polymerizing into higher order structures, either dynamically or statically, to perform structural roles during a variety of cellular processes. In eukaryotes, the most well-studied cytoskeletal proteins are actin, tubulin, and intermediate filaments, and are essential for cell shape and movement, chromosome segregation, and intracellular cargo transport. Prokaryotes often harbor homologs of these proteins, but in bacterial cells, these homologs are usually not employed in roles that can be strictly defined as 'cytoskeletal'. However, several bacteria encode other proteins capable of polymerizing which, although they do not appear to have a eukaryotic counterpart, nonetheless appear to perform a more traditional 'cytoskeletal' function. In this review, we discuss recent reports that cover the structures and functions of prokaryotic proteins that are broadly termed as cytoskeletal, either by sequence homology or by function, to highlight how the enzymatic properties of traditionally studied cytoskeletal proteins may be used for other types of cellular functions; and to demonstrate how truly 'cytoskeletal' functions may be performed by uniquely bacterial proteins that do not display homology to eukaryotic proteins.

Comparison of the Effect of Hydrostatic and Dynamic High Pressure Processing on the Enzymatic Activity and Physicochemical Quality Attributes of 'Ataulfo' Mango Nectar.

The effects of hydrostatic (HHP) and dynamic (HPH) high-pressure treatments on the activity of pectin methylesterase (PME) and polyphenol oxidase (PPO) as well as the physicochemical quality attributes of 'Ataulfo' mango nectar were assessed. HHP reduced PME relative activity by 28% at 100 MPa for 5 min but increased PPO activity almost five-fold. Contrarily, HPH did not affect PME activity, but PPO was effectively reduced to 10% of residual activity at 300 MPa and at three passes. Color parameters (CIEL*a*b*), °hue, and chroma were differently affected by each type of high-pressure processing technology. The viscosity and fluid behavior were not affected by HHP, however, HPH changed the apparent viscosity at low dynamic pressure levels (100 MPa with one and three passes). The viscosity decreased at high shear rates in nectar samples, showing a shear-thinning effect. The results highlight how different effects can be achieved with each high-pressure technology; thus, selecting the most appropriate system for processing and preserving liquid foods like fruit beverages is recommended.

Cytotoxic Activity of Polyphenol Extracts from Three Oregano Species: Hedeoma patens, Lippia graveolens and Lippia palmeri, and Antiproliferative Potential of Lippia graveolens against Two Types of Breast Cancer Cell Lines (MDA-MB-231 and MCF-7).

Oregano infusions have traditionally been used to treat some diseases related to inflammation and cancer; also, some species have shown antiproliferative activity on cancer cell lines, for example, colon and liver, and this has been attributed to its phytochemical profile, mainly its phenolic compounds. This study aimed to evaluate the cytotoxicity and antiproliferative potential of the polyphenols-rich extracts (PRE) of the oregano species H. patens, L. graveolens, and L. palmeri on breast cancer cell lines. The PRE of the three oregano species were obtained from dried leaves. The extract was characterized by determining antioxidant activity, total phenols content, and identifying the profile of phenolic acids and flavonoids by chromatography UPLC-MS/MS. Furthermore, the cytotoxicity of the extracts was evaluated in vitro on a non-cancer cell line of fibroblast NIH3T3 and the antiproliferative potential on the breast cancer cell lines MDA-MB-231 and MCF-7. L. graveolens showed the highest antioxidant capacity and significantly inhibited the proliferation of MCF-7 and MDA-MB-231 cells at non-cytotoxic concentrations in normal cells, with a similar effect to that cisplatin in MDA-MB-231 cells. Therefore, the polyphenol-rich extract from L. graveolens showed the greatest potential to guide future research on the antiproliferative mechanism of action.

Metabolomic Analysis of Phytochemical Compounds from Agricultural Residues of Eggplant (Solanum melongena L.).

The eggplant is a fruit rich in natural products and produced worldwide. However, its cultivation generates a large amount of scarcely used agricultural residues with poor chemical characterization. This study aimed to identify and quantify the metabolome and determine the composition of select phytochemicals and the overall antioxidant capacity of various anatomical parts of the plant. The plant's root, leaf, stem, and fruit were analyzed by quantitative mass spectrometry-based untargeted metabolomics and chemoinformatics, and phytochemicals were quantified by spectrophotometric analysis. Moreover, we determined the total antioxidant capacity of the distinct plant parts to infer a possible biological effect of the plant's metabolites. Various secondary metabolites were identified as terpenes, phenolic compounds, alkaloids, and saponins, distributed throughout the plant. The leaf and fruit presented the highest concentration of phenolic compounds, flavonoids, anthocyanins, and alkaloids, accompanied by the highest antioxidant capacity. Although the stem and root showed the lowest abundance of secondary metabolites, they provided around 20% of such compounds compared with the leaf and fruit. Overall, our study improved the understanding of the eggplant metabolome and concluded that the plant is rich in secondary metabolites, some with antioxidant properties, and shows potential nutraceutical and biopharmaceutical applications.

The impact of quorum sensing on the modulation of phage-host interactions.

Bacteriophages are the most diverse and abundant biological entities on the Earth and require host bacteria to replicate. Because of this obligate relationship, in addition to the challenging conditions of surrounding environments, phages must integrate information about extrinsic and intrinsic factors when infecting their host. This integration helps to determine whether the infection becomes lytic or lysogenic, which likely influences phage spreading and long-term survival. Although a variety of environmental and physiological clues are known to modulate lysis-lysogeny decisions, the social interplay among phages and host populations has been overlooked until recently. A growing body of evidence indicates that cell-cell communication in bacteria and, more recently, peptide-based communication among phage-phage populations, affect phage-host interactions by controlling phage lysis-lysogeny decisions and phage counter-defensive strategies in bacteria. Here, we explore and discuss the role of signal molecules as well as quorum sensing and quenching factors that mediate phage-host interactions. Our aim is to provide an overview of population-dependent mechanisms that influence phage replication, and how social communication may affect the dynamics and evolution of microbial communities, including their implications in phage therapy.

Mechanochemical Synthesis of Tripodal Tris[4-(1,2,3-triazol-5-ylidene)methyl]amine Mesoionic Carbene Ligands and Their Complexation with Silver(I).

The conjugate acids of 1,2,3-triazolylidene mesoionic carbenes can be prepared in a straightforward fashion by alkylation of 1-substituted 1,2,3-triazoles. However, this becomes a much more challenging proposition when other nucleophilic centers are present, which has curtailed the development of ligands containing multiple 1,2,3-triazolylidene donors. Herein, methylation of a series of tris[(1-aryl-1,2,3-triazol-4-yl)methyl]amines possessing both electron-rich and electron-deficient aromatic substituents, using Me3OBF4, is shown to proceed with much higher chemoselectivity under mechanochemical conditions than when conducted in solution. This provides a means to reliably access a series of tricationic tris[4-(1,2,3-triazolium)methyl]amines in good yields. DFT calculations suggest that a potential reason for this change in regioselectivity is the difference between the background dielectric of the DCM solution versus the solid state, which is predicted to have a large effect on the relative thermodynamic driving force for alkylation of the tertiary amine center versus the triazole rings. Homoleptic silver complexes of the triazolylidene ligands derived therefrom, of formulas [Ag3(1a-d)2](X)3 (X- = BF4-, TfO-), have been isolated and fully characterized. In the case of the ligand bearing the smallest aryl substituents, 1b, argentophilic interactions yield a triangular Ag3 core. The [Ag3(1a-d)2](X)3 silver salts are viable agents for transmetalation to other transition metals, demonstrated here for cobalt. In the case of 1a, the complex [CoII(1a)(NCMe)](OTf)2 was obtained. Therein, the bulky mesityl substituents enforce a tetrahedral geometry, in which only the triazolylidene donors of 1a coordinate (i.e., it acts as a tridentate ligand). Transmetalation of the less sterically encumbered ligand 1b yields six-coordinate cobalt(III) complexes, [CoIII(1b)(Cl)(NCMe)](OTf)2 and [CoIII(1b)(NCMe)2](OTf)3, in which the ligand coordinates in a tetradentate fashion. These are the first examples of tris(1,2,3-triazolylidene) ligands containing an additional coordinating heteroatom and, more generally, of tetradentate 1,2,3-triazolylidene ligands. Crucially, we believe that the divergent chemoselectivity under mechanochemical conditions (vs conventional solution-based chemistry) demonstrated herein offers a pathway by which other challenging synthetic targets, including further multidentate carbene ligands, can be prepared in superior yields.

Mechanosynthesis of Higher-Order Cocrystals: Tuning Order, Functionality and Size in Cocrystal Design*.

The ability to rationally design and predictably construct crystalline solids has been the hallmark of crystal engineering research. To date, numerous examples of multicomponent crystals comprising organic molecules have been reported. However, the crystal engineering of cocrystals comprising both organic and inorganic chemical units is still poorly understood and mostly unexplored. Here, we report a new diverse set of higher-order cocrystals (HOCs) based on the structurally versatile-yet largely unexplored-phosph(V/V)azane heterosynthon building block. The novel ternary and quaternary cocrystals reported are held together by synergistic and orthogonal intermolecular interactions. Notably, the HOCs can be readily obtained either via sequential or one-pot mechanochemical methods. Computational modelling methods reveal that the HOCs are thermodynamically driven to form and that their mechanical properties strongly depend on the composition and intermolecular forces in the crystal, offering untapped potential for optimizing material properties.

The crystal structure of the RsbN-σBldN complex from Streptomyces venezuelae defines a new structural class of anti-σ factor.

Streptomyces are filamentous bacteria with a complex developmental life cycle characterized by the formation of spore-forming aerial hyphae. Transcription of the chaplin and rodlin genes, which are essential for aerial hyphae production, is directed by the extracytoplasmic function (ECF) σ factor BldN, which is in turn controlled by an anti-σ factor, RsbN. RsbN shows no sequence similarity to known anti-σ factors and binds and inhibits BldN in an unknown manner. Here we describe the 2.23 Å structure of the RsbN-BldN complex. The structure shows that BldN harbors σ2 and σ4 domains that are individually similar to other ECF σ domains, which bind -10 and -35 promoter regions, respectively. The anti-σ RsbN consists of three helices, with α3 forming a long helix embraced between BldN σ2 and σ4 while RsbN α1-α2 dock against σ4 in a manner that would block -35 DNA binding. RsbN binding also freezes BldN in a conformation inactive for simultaneous -10 and -35 promoter interaction and RNAP binding. Strikingly, RsbN is structurally distinct from previously solved anti-σ proteins. Thus, these data characterize the molecular determinants controlling a central Streptomyces developmental switch and reveal RsbN to be the founding member of a new structural class of anti-σ factor.

Anthocyanin Induction by Drought Stress in the Calyx of Roselle Cultivars.

Abiotic factors can alter the chemical profile of crops and the number of compounds they contain. In this study, the anthocyanin and anthocyanidin contents, determined by ultra-performance liquid chromatography (UPLC-MS/MS), and the colour attributes of the calyces of three cultivars of Hibiscus sabdariffa subjected to three water stress regimes during the stage of physiological maturity were investigated. The total anthocyanin content in calyx increased relative to the control content under a 65% moisture irrigation regime. Among the cultivars, UAN16-2 showed the greatest increases in the contents of cyanidin, delphinidin 3-O-glucoside, cyanidin 3-O-glucoside, and cyanidin 3-O-sambubioside. The content of cyanidin 3-O-sambubioside showed the greatest increase, increasing by 55% relative to the control level. The contents of these compounds are correlated with colour attributes such as luminosity. Water stress under the 33% moisture condition during plant development led to decreased anthocyanin contents in all of the roselle cultivars.

Peptides in Colorectal Cancer: Current State of Knowledge.

Colorectal cancer (CRC) is the second most deadly and the third most commonly diagnosed cancer in the world. CRC treatment is mainly based on surgery, chemotherapy, and even though the probability of complications after surgery is very low, chemo drugs affect the patient's quality of life. Multiple studies have shown a strong correlation between diet and the onset and progression of CRC. Thus, the consumption of dietary nutraceuticals for its treatment and prevention has been suggested as a promising option. Peptides have increasingly become of interest in human health due to their antioxidant, antihypertensive, and anticancer potential. In recent years, there have been extensive reports on peptides with anti-tumor activity, and some studies suggest that peptides modulate cell proliferation, evasion of cell death, and metastasis in malignant cells. Plant-derived peptides such as soybean, bean, and rice have received main attention. In this review, we show evidence of several mechanisms through which bioactive peptides exert anti-tumor activity over in vitro and in vivo CRC models. We also report the current status of major production techniques, as well as limitations and future perspectives. Graphical Abstract.

N-Bridged Acyclic Trimeric Poly-Cyclodiphosphazanes: Highly Tuneable Cyclodiphosphazane Building Blocks.

We have synthesized a completely new family of acyclic trimeric cyclodiphosphazane compounds comprising NH, Ni Pr, Nt Bu and NPh bridging groups. In addition, the first NH-bridged acyclic dimeric cyclophosphazane has been produced. The trimeric species display highly tuneable characteristics so that the distance between the terminal N(H)R moieties can be readily modulated by the steric bulk present in the bridging groups (ranging from ≈6 to ≈10 Å). Moreover, these species exhibit pronounced topological changes when a weak non-bonding NH⋅⋅⋅π aryl interaction is introduced. Finally, the NH-bridged chloride binding affinities have been calculated and benchmarked along with the existing experimental data available for monomeric cyclodiphosphazanes. Our results underscore these species as promising hydrogen bond donors for supramolecular host-guest applications.

Influence of environmental and genetic factors on 3-hydoxypropionaldehyde production by Lactobacillus reuteri.

The influence of environmental factors such as glycerol concentration, time of production, presence of Escherichia coli, and two different strains of Lactobacillus reuteri (ATCC 55730 and ATCC 53608) on 3-hydroxypropionaldehyde (3-HPA) production was analyzed. Additionally, the influence of those factors on gene expression in the 3-HPA production pathway was evaluated. The genes studied were GldC, cbiP, and Lreu_1734. The results of this study showed that the principal environmental factors that influence 3-HPA production are glycerol concentration and Lactobacillus reuteri strain. As glycerol concentration increased, 3-HPA content increased. The greatest 3-HPA concentration (56.6 mM ±5.99) was achieved by L. reuteri ATCC 55730. Gene expression was also affected by environmental factors. Factor that showed the greatest influence were also strain and glycerol concentration. The genes cbiP, GldC, and Lreu_1734 had basal gene expression in glycerol absence; however, glycerol regulated its expression. Glycerol induced overexpression of cbiP and GldC genes (Strain ATCC 53608), probably to ensure its efficient utilization. On the contrary, glycerol concentration suppressed Lre_1734 expression in both analyzed strains, as a mechanism for 3-HPA accumulation. Down-regulation was observed in all the genes tested in strain ATCC 55730, probably due to feedback inhibition by 3-HPA.

Broad Scope Synthesis of Ester Precursors of Nonfunctionalized Chiral Alcohols Based on the Asymmetric Hydrogenation of α,ß-Dialkyl-, α,ß-Diaryl-, and α-Alkyl-ß-aryl-vinyl Esters.

The catalytic asymmetric hydrogenation of trisubstituted enol esters using Rh catalysts bearing chiral phosphine-phosphite ligands (P-OP) has been studied. Substrates covered comprise α,ß-dialkyl, α-alkyl-ß-aryl, and α,ß-diarylvinyl esters, the corresponding hydrogenation products being suitable precursors to prepare synthetically relevant chiral nonfunctionalized alcohols. A comparison of reactivity indicates that it decreases in the order: α,ß-dialkyl > α-alkyl-ß-aryl > α,ß-diaryl. Based on the highly modular structure of P-OP ligands employed, catalyst screening identified highly enantioselective catalysts for α,ß-dialkyl (95-99% ee) and nearly all of α-alkyl-ß-aryl substrates (92-98% ee), with the exception of α-cyclohexyl-ß-phenylvinyl acetate which exhibited a low enantioselectivity (47% ee). Finally, α,ß-diarylvinyl substrates showed somewhat lower enantioselectivities (79-92% ee). In addition, some of the catalysts provided a high enantioselectivity in the hydrogenation of E/Z mixtures (ca. Z/E = 75:25) of α,ß-dialkylvinyl substrates, while a dramatic decrease on enantioselectivity was observed in the case of α-methyl-ß-anisylvinyl acetate (Z/E = 58:42). Complementary deuteration reactions are in accord with a highly enantioselective hydrogenation for both olefin isomers in the case of α,ß-dialkylvinyl esters. In contrast, deuteration shows a complex behavior for α-methyl-ß-anisylvinyl acetate derived from the participation of the E isomer in the reaction.