A structure–activity relationship study on antiosteoclastogenesis effect of triterpenoids from the leaves of loquat (Eriobotrya japonica)

Our previous results elucidated that the leaves of Eriobotrya japonica possessed the potential to suppress ovariectomy-induced bone mineral density deterioration, and ursolic acid, the major bioactive component in these leaves, suppressed the osteoclast differentiation. The aim of this study was to discover more candidates for development of novel antiosteoclastogenesis agents from the leaves of E. japonica. Phytochemical analysis following a cell-based osteoclastic tartrate-resistant acid phosphatase (TRAP) activity assay revealed 11 more compounds with a potent antiosteoclastogenesis effect. The potency of ursane-type triterpenoids from the leaves of E. japonica prompted us to investigate the structure–activity relationships underlying their antiosteoclastogenesis. The results revealed that both the hydroxyl group at C-3 and the carboxylic group at C-17 played indispensable roles in the antiosteoclastogenesis activity of ursane-type triterpenoids. The configuration at C-3 (a beta-form of the hydroxyl group) was found to be important for this activity. While introducing a hydroxyl group at C-19 increased the inhibitory activity of ursane-type triterpenoids carrying an alpha-form hydroxyl group at C-3. The bioactivity analyses of ursolic acid and oleanolic acid demonstrated that the antiosteoclastogenesis effect of ursolic acid may be related to different positions of the C-29 and C-30 methyl groups on the E-ring, since oleanolic acid showed limited activity. The addition of a hydroxyl group at C-2 would dramatically improve the inhibition of oleanane-type triterpenoids. Collectively, these findings could provide important clues for the improvement of multi-targeted antiosteoclastogenesis agents from the leaves of E. japonica.     

First-principles study on the structures and electronic properties of graphene-supported Nin (n = 1–6) clusters

ABSTRACT

The structural and electronic properties, such as adsorption energy, magnetic property, and charge-transferring process of Ni_n (n?=?1–6) clusters interacting with pristine, strained and defective graphene were investigated by using the density functional theory calculations with the Perdew–Burke–Ernzerhof exchange-correlation energy functional. By introducing strain and defects, the stability of the cluster-graphene system was improved significantly. The magnetic moments increased monotonically for Ni_n clusters on pristine and strained graphene while exhibited an oscillating behaviour for defective graphene. On the other hand, more charges being transferred from Ni_n clusters to defective graphene were observed compared with pristine and strained graphene.     

A preliminary study on the distribution patterns of endemic species of Fulgoromorpha (Hemiptera,?Auchenorrhyncha) in Iran

Iran is known as the most complex and varied country in southwest Asia, in terms of geography, vegetation, climate and consequently biological diversity. The rather high number of recorded endemic species of Fulgoromorpha in Iran indicates a high potential for speciation in some areas.In this study, in order to identify the endemic zones for Fulgoromorpha of Iran, three main biogeographic regions of the country were divided into 13 primary zones, mainly according to the distribution of published and unpublished locality records of endemic species. Using Venn diagrams and cluster analyses on the primary zones, 6 final endemic zones were recognized: Caspian zone, southern slopes of Alborz, Zagros Mountains, Kerman Mountains, Khorasan Mountains, and Baluchestan and Persian Gulf coasts. Then a similarity map was produced for endemic zones using a Multidimensional analysis (Alscal) and the differences between the positions of the same zones in the similarity and geographic maps were discussed.     

A molecular dynamics simulation study of the effect of water–graphene interaction on the properties of confined water

The role of water in determining the structure and stability of biomacromolecules has been well studied. In this work, molecular dynamics simulations have been applied to investigate the effect of surface hydrophobicity on the structure and dynamics of water confined between graphene surfaces. In order to evaluate this effect, we apply various attractive/repulsive water–graphene interaction potentials (hydrophobicity). The properties of confined water are studied by applying a purely repulsive interaction potential between water–graphene (modelled as a repulsive r^?12 potential) and repulsive–attractive forces (modelled as an LJ(12-6) potential). Compared to the case of a purely repulsive graphene–water potential, the inclusion of repulsive–attractive forces leads to formation of sharp peaks for density and the number of hydrogen bonds. Also, it was found that repulsive–attractive graphene–water potential caused slower hydrogen bonds dynamics and restricted the diffusion coefficient of water. Consequently, it was found that hydrogen bond breakage and formation rate with the repulsive r^?12 potential model, will increase compared to the corresponding water confined with the LJ(12-6) potential.     

Binding properties of Ru(II) polypyridyl complexes with poly(U)·poly(A)*poly(U) triplex: the ancillary ligand effect on third-strand stabilization

The binding properties of [RuL₂(mip)]²⁺ {where L is 1,10-phenanthroline (phen) or 4,7-dimethyl-1,10-phenanthrollne (4,7-dmp) and mip is 2′-(3″,4″-methylenedioxyphenyl)imidazo[4′,5′-f][1,10]phenanthroline} with regard to the triplex RNA poly(U)·poly(A)*poly(U) were investigated using various biophysical techniques and quantum chemistry calculations. In comparison with [Ru(4,7-dmp)₂(mip)]²⁺, remarkably higher binding affinity of [Ru(phen)₂(mip)]²⁺ for the triplex RNA poly(U)·poly(A)*poly(U) was achieved by changing the ancillary ligands. The stabilization of the Hoogsteen-base-paired third strand was improved by about 10.9 °C by [Ru(phen)₂(mip)]²⁺ against 6.6 °C by [Ru(4,7-dmp)₂(mip)]²⁺. To the best of our knowledge, [Ru(phen)₂(mip)]²⁺ is the first metal complex able to raise the third-strand stabilization of poly(U)·poly(A)*poly(U) from 37.5 to 48.4 °C. The results reveal that the ancillary ligands have an important effect on third-strand stabilization of the triplex RNA poly(U)·poly(A)*poly(U) when metal complexes contain the same intercalative ligands.     

Effect of the alkaline cations on the stability of the model polynucleotide poly(dG-dC)·poly(dG-dC)

When the model polynucleotide poly(dG-dC)?poly(dG-dC) [polyGC] is titrated with a strong acid (HCl) in unbuffered aqueous solutions containing the chlorides of the alkali metals in the concentration range 0.010?M-0.600?M, two transitions in the absorbance vs. pH plots are evidenced, characterized by the constants pK(a(?)) and pK(a(?)). The limiting values at infinite saline concentrations of these two constants, namely pK(∞)(a(?)) and pK(∞)(a(?)) obtained making use of the "one site saturation constant" equation or, in turn, of the double logarithmic plot: pK(a) vs. log([salt]?1), exhibit a clear dependence on the nature of the cations. The effects of the different alkali cations on the pK(∞)(a) values follow the Hofmeister series. In fact, the pK(∞)(a(?)) and the pK(∞)(a(?)) values are smaller for Li+ and Na+ than for Rb+ and Cs+, with K+ at the border between the two, showing that the transitions require higher concentrations of protons to occur in the presence of high concentrations of the cosmotropic ions.     

Integrated study of fauna and microflora from the Early Devonian (Pragian–Emsian) of northwestern Argentina

The Devonian System in northern Argentina has been broadly analysed, but details of its lithologies, biostratigraphy and fossil content have not been presented in a comprehensive study. We performed the first integrative analysis of the palynological and macrofossil content from the Pescado Formation at the Zenta Range, Argentina. We define a new species of cryptospore and extend the stratigraphic record of the ichnogenus Psammichnites isp. for South America. The stratigraphic ranges of the palynomorphs suggest a time span from the ?late Lochkovian to Pragian–earliest Emsian, but the co-occurrences of key invertebrates narrow the age of the beds to the late Pragian and early Emsian. Moreover, sedimentary analysis indicates a proximal shoreface–foreshore depocenter during this time range for the Zenta region. The contraction phase of the basin during the middle Pragian and Emsian is evidenced by the presence of sand bodies at the top of the column and the higher supply of terrigenous components. During this regression event, a low diversity Malvinokaffric Realm brachiopod assemblage occurs, with dominance of Australospirifer hawkinsi. The predominance of the latter species during this event is coeval with the first decline of the Malvinokaffric Realm in the neighbouring Paraná basin.     

Growth of Pseudomonas chlororaphis on apolyester–polyurethane and the purification andcharacterization of a polyurethanase–esterase enzyme

A Pseudomonas chlororaphis was found to degrade and utilize apolyester polyurethane as a sole carbon and energy source. Polyurethane utilization by P.chlororaphis followed simple Michaelis–Menten kinetics. The K_s and μ_max values were 0.802 mg·ml⁻¹ and 1.316 doublings·h⁻¹, respectively. The enzymes from P. chlororaphis responsible for polyurethanedegradation were found to be extracellular. Analysis of the polyurethane degrading proteins, usingnon-denaturing polyacrylamide gel electrophoresis, revealed three active protein bands with R_f values of 0.25, 0.417 and 0.917. A polyurethane degrading enzyme was purifiedand displayed esterase activity. This enzyme was inhibited by phenylmethylsulfonyl fluoride andhad a molecular weight of 27,000 daltons.     

Effects of α-lipoic acid and myo-inositol supplementation on the oocyte environment of infertile obese women: A preliminary study

Obesity is becoming pandemic and is associated with impaired reproductive potential. Oxidative stress, low-grade chronic inflammation and mitochondrial dysfunctions, which characterize obesity, strongly affect oocyte environment and function.Supplementation with antioxidant and anti-inflammatory compounds has been suggested to improve fertility. Here we evaluated the effect of α-lipoic acid and myo-inositol supplementation on the oocyte environment of infertile obese women.Nineteen normal-weight and twenty-three obese women, infertile for non-ovarian reasons, were recruited. For two months before ovarian stimulation, all women received 400 μg/die folic acid, whereas 15 obese were additionally supplemented with 800 mg α-lipoic acid, 2 g myo-inositol/die.Antioxidant capacity was measured in follicular fluid by enzymatic assay; mitochondrial DNA (mtDNA) content and mRNA levels of two respiratory chain subunits were analyzed in granulosa cells by Real-time PCR.Pregnancy rate was similar between normal-weight and treated obese, and lower in untreated obese patients. Supplemented women showed significantly higher antioxidant levels in follicular fluid compared to the two groups taking only folic acid. Conversely, granulosa cells mtDNA content was decreased in treated and higher in untreated obese patients compared to normal-weight women, suggesting mtDNA increases to compensate for oxidative-stress damages. Reduced expression of respiratory subunits in untreated obese may confirm mitochondria impairment. Interestingly, mtDNA levels inversely correlated to both total and metaphase II oocyte number.In this preliminary study, combined supplementation of α-lipoic acid and myo-inositol in infertile obese women was associated with amelioration in the oxidative status of the oocyte environment, possibly contributing to a higher pregnancy rate.     

Lipase-catalyzed synthesis of poly(ε-caprolactone) and characterization of its solid-state properties

Abstract

Ring-opening polymerization of ε-caprolactone has been successfully conducted using an immobilized form of Candida antarctica lipase B as catalyst. The effects of enzyme concentration, reaction medium, reaction temperature and time on monomer conversion and product molecular weight were investigated. Through optimization of reaction conditions, poly(ε-caprolactone) (PCL) was obtained with 99% monomer conversion and a number-average molecular weight (M_n) of 18870 g/mol. The reaction system was then scaled up, and PCL was synthesized in 78% isolated yield, with M_n and polydispersity index of 41540 g/mol and 1.69, respectively. The solid-state properties of this sample were systematically evaluated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and polarized optical microscopy (POM). The product PCL showed excellent thermal stability, with degradation of the main chain in the temperature range of 280–450°C. Remarkably, this high molecular weight PCL was a typical crystalline polymer with a high degree of crystallinity observed by DSC, WAXD and POM.     

The nature of different influence of Cd<Superscript>2+</Superscript> ions on the conformational equilibrium of triple-stranded polyribonucleotides poly(U)•poly(A)•poly(U) and poly(I)•poly(A)•poly(I) in aqueous solutions

The influence of Cd²⁺ ions on the conformational equilibrium of single-stranded (poly(U), poly(A), poly(I)) and triple-stranded polyribonucleotides (A2I, A2U) in aqueous solutions (0.1 M Na⁺ pH 7) has been investigated using difference UV spectroscopy and thermal denaturation. Analysis of the shape and intensity of the DUV spectra of poly(A), poly(I), and A2I has revealed the presence of two types of complex formed as a result of (i) interaction between Cd²⁺ and the N7 atoms of purines, producing macrochelates; and (ii) binding of Cd²⁺ to the N1 atoms of poly(A) and poly(I). Since Cd²⁺ ions are not bound to heteroatoms of the bases in A2U, the conformation of the structure remains stable up to 0.02 M Cd²⁺. There is a critical Cd²⁺ concentration (～1.5?10^?4 M) above which A2I assumes a new helical conformation with lower thermal stability. It is supposed that, upon the formation of the “metallized” A2I triplex, the Cd²⁺ ions are located inside the triple helix and form bridges between the hypoxanthine and adenine of the homopolynucleotide strands.     

Synthesis of new poly(ether–urethane–urea)s based on amino acid cyclopeptide and PEG: study of their environmental degradation

Conventional polyurethanes (PUs) are among biomaterials not intended to degrade but are susceptible to hydrolytic, oxidative and enzymatic degradation in vivo. Biodegradable PUs are typically prepared from polyester polyols, aliphatic diisocyanates and chain extenders. In this work we have developed a degradable monomer based on α-amino acid to accelerate hard segment degradation. Thus a new class of degradable poly(ether–urethane–urea)s (PEUUs) was synthesized via direct reaction of 4,4′-methylene-bis(4-phenylisocyanate) (MDI), l-leucine anhydride (LA) and polyethylene glycol with molecular weight of 1,000 (PEG-1000) as polyether soft segment. The resulting polymers are environmentally biodegradable and thermally stable. Decomposition temperatures for 5 % weight loss occurred above 300 °C by TGA in nitrogen atmospheres. Some structural characterization and physical properties of these polymers before and after degradation in soil, river water and sludge are reported. The environmental degradation of the polymer films was investigated by SEM, FTIR, TGA, DSC, GPC and XRD techniques. A significant rate of degradation occurred in PEUU samples under river water and sludge condition. The polymeric films were not toxic to E. coli (Gram negative), Staphylococcus aureus and Micrococcus (Gram positive) bacteria and showed good biofilm formation on polymer surface. Our results show that hard segment degraded selectively as much as soft segment and these polymers are susceptible to degradation in soil and water. Thus our study shows that new environment-friendly polyurethane, which can degrade in soil, river water and sludge, is synthesized.     

Isolation and re-association of the subunits from the pro-(carboxypeptidase A)–pro-(proteinase E) binary complex from pig pancreas

The component subunits of the pro-(carboxypeptidase A)–pro-(proteinase E) binary complex from pig pancreas were separated with a high recovery (80–95%) of their original potential activity. The isolated subunits and the reconstituted complex have properties similar to those of the corresponding natural species. The tryptic activation course of the pro-(carboxypeptidase A) subunit is substantially modified when bound to pro-(proteinase E), whereas the activation of pro-(proteinase E) is not dependent on this association.     

Stimuli-responsive materials prepared from carboxymethyl chitosan and poly(γ-glutamic acid) for protein delivery

The development of stimuli-responsive materials in response to the molecules involved in biological processes has gained increased attentions. In this work, carboxymethyl chitosan (CM-chitosan) and poly(γ-glutamic acid) (pGlu) were reacted with a naturally occurring compound, genipin, leading to the formation of genipin-crosslinked CM-chitosan/pGlu conjugates with fluorescence emissions. The genipin-conjugated polymers were sensitive to the oxidation product of glucose, gluconic acid and hydrogen peroxide (H₂O₂). Fluorescence emissions of the polymers were quenched by gluconic acid and H₂O₂. An increase in the hydrodynamic diameter together with the quenching of fluorescence indicated that the genipin-conjugated polymers were self-aggregated into nanoparticles, in response to the stimulus of gluconic acid (but not for H₂O₂). Bovine serum albumin (BSA) could be loaded in the self-aggregated nanoparticles, and the incorporated BSA slowly released from the nanoparticles under hyper-gluconic acid conditions. This material is hence proposed as a stimuli-responsive material for optical sensing and protein delivery purposes.     

Fractionation of functional polystyrenes,poly(ethylene oxide)s and poly(styrene)–b–poly(ethylene oxide) by liquid chromatography at the exclusion–adsorption transition point

The paper reports the fractionation of functional polystyrenes (PSs) and poly(ethylene oxide)s (PEOs) as well as their block copolymers, by liquid chromatography at the exclusion adsorption transition point (EATP–LC), also called “critical conditions” mode. In this specific elution mode (EATP–LC), the fractionation is only governed by the nature and the number of functions attached to the polymer backbone, independent of the molar mass distribution of the whole sample. Functional polystyrenes (α- and/or α,ω-alcohol-, acetal-, aldehyde- and acidic-PS) could be readily separated from non-functional polystyrenes under various chromatographic conditions. The technique also allowed the fractionation of poly(ethylene oxide)s and PS–PEO block copolymers. In the latter cases, moderately polar columns (grafted silica) and water-based polar eluents were required to obtain a satisfactory fractionation.     

Lipoxygenase of the thermophilic bacteria thermoactinomyces vulgaris—properties and study on the active site

• 1.1. A lipoxygenase activity was purified from Thermoactinomyces vulgaris and some of its properties were characterized.
• 2.2. The enzyme showed a temperature activity range of 40–55°C with still significant activity over 60°C.
• 3.3. The pH of activity on linoleic acid had a broad range with an optimum at pH 6.0 and a weaker one at pH 11.0.
• 4.4. On arachidonic acid the pattern was narrow bell-shaped with an optimum at pH 6.5.
• 5.5. The purified lipoxygenase from Th. vulgaris showed an apparent K_m of 1 mM and V_max of 0.84 μmol diene/min/mg protein.
• 6.6. It was inhibited by the oxidation products, 9-HPOD and 13-HPOD.
• 7.7. A 160,000 Da molecular weight of the enzyme was determined by molecular filtration. Methionine, tyrosine, tryptophan and cysteine are apparently involved in its activity.

     

A preliminary checklist of the ants (Hymenoptera,?Formicidae) of Andorra

Within the last decade, checklists of the ant fauna of several European countries have been published or updated. Nevertheless, no ant checklists have hitherto been published for the principality of Andorra, a small landlocked country located in the eastern part of the Pyrenees. This work presents a critical list of the ant species of Andorra based on a review of the literature and on the biological material we collected during several field campaigns conducted in Andorra since the year 2005. Seventy-five species belonging to 21 genera of Formicidae were recorded. Nine species were recorded for the first time in Andorra: Aphaenogaster gibbosa (Latreille, 1798), Camponotus lateralis (Olivier, 1792), Camponotus piceus (Leach, 1825), Formica exsecta Nylander, 1846, Lasius piliferus Seifert, 1992, Tapinoma madeirense Forel, 1895, Temnothorax lichtensteini (Bondroit, 1918), Temnothorax niger (Forel, 1894), Temnothorax nigriceps (Mayr, 1855). The most speciose genera were Formica Linnaeus, 1758 and Temnothorax Forel, 1890 with 14 and 12 species, respectively. The ant fauna of Andorra is mostly dominated by Central European species (some are typical cold climate specialists); however species belonging to the Mediterranean ant fauna were also found. This can be explained by the particular geographic situation of Andorra which is characterized by a high mountain Mediterranean climate.     

A morphometric study of the Abies religiosa–hickelii–guatemalensis complex (Pinaceae) in Guatemala and Mexico

This morphometric study of the geographic variation in the Abies religiosa–hickelii–guatemalensis complex is based on samples from 15 Guatemalan and 12 Mexican populations, two populations of A. religiosa s.str. and A. hickelii s.str., and herbarium specimens of A. hickelii, A. vejarii and varieties of A. guatemalensis. The multivariate methods employed were principal components analysis, and UPGMA clustering. The multivariate and univariate analyses based on 231 operational taxonomic units imply that although morphological differences exist distinct morphospecies cannot be recognized within the A. religiosa–hickelii–guatemalensis complex. A Mantel’s test reports that taxonomic dissimilarities are significantly related to geographic distance. We suggest, therefore, that A. religiosa, A. hickelii and A. guatemalensis are merged so that A. hickelii is referred to as A. religiosa subsp. hickelii (Flous & Gaussen) U. Strandby, K.I. Chr. & M. Sørensen, comb. et stat. nov. and A. guatemalensis as A. religiosa subsp. mexicana (Martínez) U. Strandby, K.I. Chr. & M. Sørensen, comb. nov. According to our analyses A. vejarii cannot retain its status as a separate taxon as the material studied is nested within A. religiosa subsp. mexicana.