Bile acids in asymmetric synthesis and chiral discrimination

An overview on the use of bile acid‐based compounds able to catalyze transformations, control the stereochemical course of a given reaction, recognize and bind other molecules, is presented. The recent developments in inclusion discrimination of chiral and achiral guests and enantioselective recognition achieved by bile acid are described with suitable examples. Chirality 2010. © 2009 Wiley‐Liss, Inc.     

Transfer factor prevents relapses in herpes keratitis patients: A pilot study

Transfer Factor is a dialysable moiety obtained from immune lymphocytes. It has been successfully used for the treatment of several viral infections including labial and genital herpes. In the present study, thirty-three patients with low immune response to HSV antigens and suffering from herpes ocular infections were orally treated with HSV-specific transfer factor (TF). Their relapse index was reduced from 20.1 before treatment to 0.51 after TF administration, with only 6/33 patients relapsing. Although this is not a placebo-controlled-randomized study, the results suggest that TF specific for HSV antigens may be efficacious for preventing relapses of ocular herpes infections as has been the case with genital and labial localisations.Abbreviations CMI Cell-mediated immunity - CMV Cytomegalo-virus - EBV Epstein-Barr virus - HIV Human immunodeficiency virus - HK Herpes keratitis - HSV Herpes simplex virus - IRI Individual relapse index - KU Kerato-uveitis - LMT Leucocyte migration test - LST Lymphocyte stimulation test - MIF Migration inhibition factor - RHK Relapsing herpes keratitis - TF Transfer factor     

Spectrophotometric measurement of hydroxylamine and its O-alkyl derivatives

An easy spectrophotometric method was developed to quantify compounds having an ONH₂ (amino-oxy) function (e.g., hydroxylamine, canaline, O-aminoserine, and amino-oxy acetic acid). Stoichiometric reactions occur, in practice, between the amino-oxy compounds and the aldehydic group of pyridoxal 5′-phosphate in aqueous solution. When the reaction had reached equilibrium the concomitant decrease in absorption at 405 nm was used as the measure of the amino-oxy functions. Thus it is possible to determine amino-oxy compounds at about the same concentration as pyridoxal 5′-phosphate can be measured spectrophotometrically. The present method was applied to follow the enzymic hydrolysis of canavanine to canaline. Based on the measured apparent kinetic constants, a specific way to determine hydroxylamine among its O-alkylethers was advised, as well.     

Animal Rennets as Sources of Dairy Lactic Acid Bacteria

The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions.     

An assessment of red list data for the Pezizomycotina (Ascomycota): Umbria (Italy) as a test case

Abstract

A Red List of all 108 Pezizomycotina (Ascomycota) species recorded in Umbria Region (central Italy) is provided. According to the IUCN categories and criteria, 60.18% of the assessed species are classified as threatened, whereas 12.96% are Near Threatened (NT), 1.86% are Least Concerned (LC) and a noteworthy amount of 25% are Data Deficient (DD). As a consequence of the downlisting applied to the majority of the assessed taxa, according to the guidelines for application of IUCN red list criteria at Regional level, only 1.54% of the threatened species is Critically Endangered (CR), while 46.15% are Endangered (EN) and 52.31% are Vulnerable (VU). Given that the present work represents the first complete regional red list of Pezizomycotina in Italy, and that a national, as well as a European red list do not exist to date, it could be considered as a case study for other Italian Regions as well as for other European countries, aiming at the compilation of a national and European red list of this fungal group mostly overlooked in conservation strategies.     

Cognitive Modulation of Psychophysical,Respiratory and Autonomic Responses to Cold Pressor Test

In healthy subjects with high hypnotisability (highs) under hypnosis, subjectively effective suggestions for analgesia abolish the increases in blood pressure associated with cold pressor test (cpt) by reducing the peripheral vascular resistance. The aim of the present study was to investigate the effects of the suggestions of analgesia on the responses to cpt in healthy highs (n = 22) and in low hypnotisable participants (lows, n = 22) out of hypnosis. Cpt was administered without (CPT) and with suggestions for analgesia (CPT+AN). Psychophysical (pain intensity, pain threshold, cpt duration (time of immersion) and pain tolerance, defined as the difference between cpt duration and pain threshold), respiratory (amplitude and frequency) and autonomic variables (tonic skin conductance, mean RR interval (RR = 1/heart rate), blood pressure, skin blood flow) were studied. The suggestions for analgesia increased cpt duration and RR in both groups, but decreased pain intensity and enhanced pain threshold only in highs; in both groups they did not modulate systolic blood pressure, tonic skin conductance and skin blood flow; thus, increased parasympathetic activity appears responsible for the heart rate reduction induced by suggestions in both groups. In conclusion, our findings show that suggestions modulate pain experience differentially in highs and lows, and are partially effective also in lows. We hypothesize that the mechanisms responsible for the efficacy of suggestions in healthy lows may be involved also in their efficacy in chronic pain patients with low hypnotisability.     

Silver(I) poly(1,2,3-benzotriazolyl)borate complexes containing mono- and bidentate phosphine coligands

New silver(I) derivatives [Ag{H_nB(btz)_4 − n}(PR₃)_x] (n = 1 or 2, x ranging from 1 to 3), containing monodentate tertiary phosphines and anionic poly(benzotriazol-1-yl)borates, have been prepared from the reaction of AgNO₃ with PR₃ (R = Ph, o-tolyl, m-tolyl, p-tolyl, Bns) and K[H₂B(btz)₂], or K[HB(btz)₃] (Hbtz = 1,2,3-benzotriazole). When the reaction between K[H₂B(btz)₂] and AgNO₃ was carried out in the presence of dppe (1,2-bis(diphenylphosphino)ethane), or dppf (1,1′-bis(diphenylphosphino)ferrocene), compounds [Ag{H₂B(btz)₂}]₂(L) (L = dppe or dppf) formed, the diphosphine acting as a bidentate bridging P₂-donor. Solid state and solution properties of all complexes have been investigated through analytical and spectroscopic measurements (IR, ¹H, ³¹P NMR), the ¹H and ³¹P NMR spectra being interpreted in terms of equilibria that involve mono- and di-nuclear complexes. Adducts [Ag{HB(btz)₃}(PPh₃)₃] · (1/2H₂O) and [Ag{H₂B(btz)₂}]₂ (dppf) have been characterised by single crystal X-ray studies. In the former, the HB(btz)₃ is unidentate in an NAgP₃ coordination environment; the latter is a dimer, the dppf bridging the two silver atoms, while the H₂B(btz)₂ ligand, which chelates one silver, bridges to the second also, the array having 2-symmetry.