Induction of cytotoxic effects and changes in DNA methylation-related gene expression in a human fibroblast cell line by the metal-organic framework [H2NMe2]3 [Tb(III)(2,6 pyridinedicarboxylate)3] (Tb-MOF)

Lanthanide metal-organic frameworks (lanthanide MOFs) may be utilized for a variety of environmental and human health applications due to their luminescent properties and high thermal and water stability. However, the cytotoxic and epigenetic effects produced in human cells are not known. Therefore, we evaluated the cytotoxic effects, internalization, and changes in the mRNA abundance of DNA methylation and demethylation enzymes by exposing human fibroblast cells to a metal-organic framework [H₂NMe₂]₃ [Tb(III)(2,6 pyridinedicarboxylate)₃] (Tb-MOF). For this purpose, the cells were exposed to six concentrations (0.05 to 1.6 mg/mL) of Tb-MOF for 48 h. Field emission electron microscopy coupled to linear energy dispersive spectroscopy (FESEM‒EDS) and confocal microscopy analysis were performed. The cytotoxicity was determined with crystal violet and MTT assays. The results demonstrated the internalization of Tb-MOF at concentrations as low as 0.05 mg/mL, as well as concentration-dependent toxicity. Additionally, we detected significant changes in the gene expression levels of DNA methyltransferases and demethylases due to the presence of Tb-MOF, suggesting that Tb-MOF could generate epigenetic changes even at low concentrations. The results of our study may establish a foundation for future research attempting to develop and apply secure nanomaterials (e.g., MOFs) to minimize damage to the environment and human health.

Microencapsulation of Red Sorghum Phenolic Compounds with Esterified Sorghum Starch as Encapsulant Materials by Spray Drying

Phenolic compounds with antioxidant properties are highly sensitive molecules, which limits their application. In response, extruded esterified starch has been proposed as efficient encapsulating material. In this work, we aim to describe the encapsulation of red sorghum phenolic compounds by spray drying using extruded phosphorylated, acetylated and double esterified sorghum starch as wall material. Their respective encapsulation yields were 77.4, 67.4 and 56.8%, and encapsulation efficiency 91.4, 89.7 and 84.6%. Degree of substitution confirmed esterification of the sorghum starch and Fourier transform infrared spectroscopy showed the significant chemical and structural changes in the extruded esterified starch loaded with phenolic compounds. Microcapsules from phosphorylated sorghum starch showed the highest endothermic transition (173.89 °C) and provided a greater protection of the phenolic compounds during storage at 60 °C for 35 days than the other wall materials. Extruded esterified sorghum starch proved to be effective material for the protection of phenolic compounds due to its high encapsulation efficiency and stability during storage.

Synthesis and succinylation of starch nanoparticles by means of a single step using sonochemical energy

In the present research work, esterified nanoparticles with 2-octen-1-ylsuccinic anhydride were synthesized from waxy corn starch, to our knowledge for the first time, in a single step of ultrasonic treatment. First, the ultrasound time to produce non-esterified nanoparticles was studied. The results showed that non-esterified nanoparticles had sizes ranging from 63 to 48 nm, as well as polydispersity indexes (PDI) ranging from 0.458 to 0.224 and ζ-potential values ranging from -16 to -24 mV in ultrasonication times ranging from 20 to 100 min. Succinylated nanoparticles were obtained at 80 min with two degrees of substitution i.e., 0.003 and 0.01, hydrodynamic sizes of 57 and 83 nm, PDI of 0.479 and 0.91, and ζ-potential values of -6.27 and -14.03 mV, respectively. The succinylation of nanoparticles was confirmed by FTIR spectroscopy, and it was possible to elucidate the conversion of amylopectin molecules into amylose blocks. The nanoparticles showed stability during storage in aqueous suspension at 4 °C. By means of the ultrasonic technology, destructuring of the waxy corn starch and, at the same time, the succinylation of the nanoparticles in a total time of 120 min was effectively achieved.

Solvent-free synthesis of 6β-phenylamino-cholestan-3β,5α-diol and (25R)-6β-phenylaminospirostan-3β,5α-diol as potential antiproliferative agents

In this paper is described a synthetic route to 6β-phenylamino-cholestan-3β,5α-diol and (25R)-6β-phenylaminospirostan-3β,5α-diol, starting from cholesterol and diosgenin, respectively. The products were obtained in two steps by epoxidation followed by aminolysis, through an environmentally friendly and solvent-free method mediated by SZ (sulfated zirconia) as catalyst. The use of SZ allows chemo- and regioselective ring opening of the 5,6α-epoxide during the aminolysis reaction eliminating the required separation of the epoxide mixture. The products obtained were spectroscopically characterized by ¹H, PENDANT ¹³C NMR and HETCOR experiments, and complemented with FTIR-ATR and HRMS. The antiproliferative effect of the β-aminoalcohols was evaluated on MCF-7 cells after 48h of incubation, by MTT and CVS assays. These methodologies showed that both compounds have antiproliferative activity, being more active the cholesterol analogue. Additionally, the cell images obtained by Harris' Hematoxylin and Eosin (H&E) staining protocol, evidenced formation of apoptotic bodies due to the presence of the obtained β-aminoalcohols in a dose-dependent manner.

(25R)-16β-Acet-oxy-3β-bromo-23',26-ep-oxy-23',25-dimethyl-5α-cholest-23,23'-en-6-one dichloro-methane monosolvate

The crystal structure of the title compound, C31H45BrO5·CH2Cl2, prepared in six steps from diosgenin, confirmed that the configurations of the stereogenic centers, positions 20S and 25R, remain unchanged during the reaction. The six-membered A, B and C rings have chair conformations. The five-membered ring D has an envelope conformation (with the methyl-substituted C atom fused to ring C as the flap) and the six-membered dihydro-pyran ring E adopts a twist-boat conformation. In the crystal, mol-ecules are linked via C-H⋯O and C-H⋯Cl hydrogen bonds, the latter involving the dichloro-methane solvent mol-ecule, forming a three-dimensional supra-molecular network.

Nosocomial outbreak of Enteroccocus gallinarum: untaming of rare species of enterococci

An unusual increase in infections caused by vancomycin-resistant Enterococcus gallinarum (VREG) was identified in May 2004, in a Colombian tertiary care teaching hospital. A case-control study was subsequently designed to identify risk factors associated with the development of infections due to these organisms. All VREG isolates were subjected to antimicrobial susceptibility testing, vancomycin resistance gene detection and pulsed-field gel electrophoresis (PFGE) typing. Additionally, the presence of genes associated with an acquired pathogenicity island of E. faecalis and a hyl-like gene of E. faecium was assessed by hybridisation assays. Eleven cases of VREG were identified between May through June 2004. VREG was isolated from blood (N=4), surgical secretions (N=4), paranasal sinus secretion (N=1), lung abscess (N=1) and urine (N=1). Infections with VREG were associated with mucositis, hospitalisation in the haematology ward and surgical unit, length of hospital stay prior to culture and invasive procedures within 30 days prior to the culture. Logistic regression found that female sex and hospitalisation in the surgical unit were independent factors for VREG infection. All isolates were identified as E. gallinarum, harboured the vanC1 gene and exhibited indistinguishable restriction patterns by PFGE. Virulence-associated genes were not detected. This is the first documented hospital-wide outbreak of VREG and highlights the fact that uncommon species of enterococci are capable of nosocomial dissemination.

A modified Christensen's urea and CLSI broth microdilution method for testing susceptibilities of six Malassezia species to voriconazole, itraconazole, and ketoconazole

Two supplemented broths (Christensen's urea with 0.1% Tween 80 and 0.5% Tween 40 and RPMI 1640 with 1% glycerol, 1% peptone, 1.8% glucose, and 0.05% Tween 80) were evaluated to determine voriconazole, itraconazole, and ketoconazole MICs for 200 Malassezia sp. isolates. Malassezia globosa and M. restricta were the least susceptible species (MICs at which 90% of the isolates tested were inhibited, 1 to >or=8 microg/ml versus 0.25 to 1 microg/ml).

Regioselective cleavage of rings E and F in sarsasapogenin

Sapogenins from the 25R and 25S series show a marked difference on the E/F regioselectivity of the spiroketal cleavage with BF(3)/Ac(2)O. In contrast to the high yield of single E-ring cleavage products from diosgenin (3) and hecogenin (5), sapogenins of the 25R series (equatorial C-27 methyl), sarsasapogenin (1, 25S series, axial C-27 methyl) yields the corresponding acetyldihydropyran, (25S)-23-acetyl-22,26-epoxy-5beta-cholest-22-ene-3beta,16beta-diyl diacetate (8), two isomeric furostenes: (E)- and (Z)-(25S)-23-acetyl-5beta-furost-22-ene-3beta,26-diyl diacetate (9 and 10) and a third one bearing an additional acetyl group: (E)-(20S,25S)-20,23-diacetyl-5beta-furost-22-ene-3beta, 26-diyl diacetate (11). The structures of the compounds were unambiguously established using two dimensional NMR techniques. The lower E/F selectivity in the cleavage of 1 is attributed to steric hindrance resulting from the axial methyl in F ring on a beta elimination forming the dihydropyran double bond in the major product 8.