Bioconversion of soy isoflavones daidzin and daidzein by <Emphasis Type="Italic">Bifidobacterium</Emphasis> strains

Twenty-two strains of Bifidobacterium, representative of eight major species of human origin, were screened for their ability to transform the isoflavones daidzin and daidzein. Most of the strains released the aglycone from daidzin and 12 gave yields higher than 90%. The kinetics of growth, daidzin consumption, and daidzein production indicated that the hydrolytic activity occurred during the growth. The supernatant of the majority of the strains did not release the aglycone from daidzin, suggesting that cell-associated β-glucosidases (β-Glu) are mainly responsible for the metabolism of soybean glyco-conjugates. Cell-associated β-Glu was mainly intracellular and significantly varied among the species and the strains. The lack of β-Glu was correlated with the inability to hydrolyze daidzin. Although S-equol production by anaerobic intestinal bacteria has been established, information on S-equol-producing bifidobacteria is contradictory. In this study, 22 bifidobacteria failed to transform daidzein into reduced metabolites under all the experimental conditions, excluding any role in the reductive pathway of daidzein toward the production of S-equol. These results suggest that selected probiotic strains of Bifidobacterium can be used to speed up the release of daidzein, improving its bioavailability for absorption by colonic mucosa and/or biotransformation to S-equol by other intestinal microorganisms.     

Oviposition of the Colorado potato beetle (Leptinotarsa decemlineata) and natural predation on its egg masses in Bt-expressing fields

Generalist predators are relevant natural enemies of the Colorado potato beetle (CPB) in Europe. In fields of insect resistant genetically modified plants (GMPs), predators could be exposed to toxins either directly (e.g., via pollen), or indirectly through feeding on herbivorous prey. Hence, they represent an important functional group to consider when studying environmental impacts of GMPs. CPB females show a ‘bet-hedging’ strategy in spatial and temporal distribution of eggs, through which the species tries to minimize the risks of progeny loss due to adverse conditions. Experimental fields of GM eggplants expressing Cry3Bb toxin and potatoes expressing Cry1Ab toxin were set up. CPB egg masses were counted on naturally infested plants at four time points during the field season of each crop. To assess predation, newly deposited egg masses were marked at the same dates. Daily visual observations were conducted recording the numbers of intact or preyed eggs and neonate larvae. In both cases, oviposition was similar between GM and control plots, as the number of egg masses per plant and the number of eggs per mass did not differ significantly between treatments. A statistical analysis of the spatial distribution of egg masses revealed a similar aggregation in the potato field, whereas in the eggplant field, the variance of the number of egg masses per plant was smaller than expected in GMP plots. The predation rate was similar between treatments. These results suggest that the ecological function of natural predation on CPB eggs in GM plots was not impaired.     

Comparison of translation loads for standard and alternative genetic codes

Background  

The (almost) universality of the genetic code is one of the most intriguing properties of cellular life. Nevertheless, several variants of the standard genetic code have been observed, which differ in one or several of 64 codon assignments and occur mainly in mitochondrial genomes and in nuclear genomes of some bacterial and eukaryotic parasites. These variants are usually considered to be the result of non-adaptive evolution. It has been shown that the standard genetic code is preferential to randomly assembled codes for its ability to reduce the effects of errors in protein translation.     

Carbonic anhydrase inhibitors: Valdecoxib binds to a different active site region of the human isoform II as compared to the structurally related cyclooxygenase II "selective" inhibitor celecoxib

The high resolution X-ray crystal structure of the adduct of human carbonic anhydrase (CA, EC 4.2.1.1) isoform II (hCA II) with the clinically used painkiller valdecoxib, acting as a potent CA II and cyclooxygenase-2 (COX-2) inhibitor, is reported. The ionized sulfonamide moiety of valdecoxib is coordinated to the catalytic Zn(II) ion with a tetrahedral geometry. The phenyl-isoxazole moiety of the inhibitor fills the active site channel and interacts with the side chains of Gln92, Val121, Leu198, Thr200, and Pro202. Its 3-phenyl group is located into a hydrophobic pocket, simultaneously establishing van der Waals interactions with the aliphatic side chain of various hydrophobic residues (Val135, Ile91, Val121, Leu198, and Leu141) and a strong offset face-to-face stacking interaction with the aromatic ring of Phe131 (the chi1 angle of which is rotated about 90 degrees with respect to what was observed in the structure of the native enzyme and those of other sulfonamide complexes). Celecoxib, a structurally related COX-2 inhibitor for which the X-ray crystal structure was reported earlier, binds in a completely different manner to hCA II as compared to valdecoxib. Celecoxib completely fills the entire CA II active site, with its trifluoromethyl group in the hydrophobic part of the active site and the p-tolyl moiety in the hydrophilic one, not establishing any interaction with Phe131. In contrast to celecoxib, valdecoxib was rotated about 90 degrees around the chemical bond connecting the benzensulfonamide and the substituted isoxazole ring allowing for these multiple favorable interactions. These different binding modes allow for the further drug design of various CA inhibitors belonging to the benzenesulfonamide class.     

Right‐handed fossil humans

Fossil hominids often processed material held between their upper and lower teeth. Pulling with one hand and cutting with the other, they occasionally left impact cut marks on the lip (labial) surface of their incisors and canines. From these actions, it possible to determine the dominant hand used. The frequency of these oblique striations in an array of fossil hominins documents the typically modern pattern of 9 right‐ to 1 left‐hander. This ratio among living Homo sapiens differs from that among chimpanzees and bonobos and more distant primate relatives. Together, all studies of living people affirm that dominant right‐handedness is a uniquely modern human trait. The same pattern extends deep into our past. Thus far, the majority of inferred right‐handed fossils come from Europe, but a single maxilla from a Homo habilis, OH‐65, shows a predominance of right oblique scratches, thus extending right‐handedness into the early Pleistocene of Africa. Other studies show right‐handedness in more recent African, Chinese, and Levantine fossils, but the sample compiled for non‐European fossil specimens remains small. Fossil specimens from Sima del los Huesos and a variety of European Neandertal sites are predominately right‐handed. We argue the 9:1 handedness ratio in Neandertals and the earlier inhabitants of Europe constitutes evidence for a modern pattern of handedness well before the appearance of modern Homo sapiens.     

The beneficial use of ultramicronized palmitoylethanolamide as add-on therapy to Tapentadol in the treatment of low back pain: a pilot study comparing prospective and retrospective observational arms

Background

This pilot study was designed to compare the efficacy of ultramicronized palmitoylethanolamide (um-PEA) as add-on therapy to tapentadol (TP) with TP therapy only in patients suffering from chronic low back pain (LBP).

Methods

This pilot observational study consists in two arms: the prospective arm and the retrospective one. In the prospective arm patients consecutively selected received um-PEA as add-on therapy to TP for 6 months; in the retrospective arm patients were treated with TP only for 6 months. Pain intensity and neuropathic component were evaluated at baseline, during and after 6 months. The degree of disability and TP dosage assumption were evaluated at baseline and after 6 months.

Results

Statistical analysis performed with generalized linear mixed model on 55 patients (30 in the prospective group and 25 in the retrospective group) demonstrated that um-PEA as add-on treatment to TP in patients with chronic LBP, in comparison to TP alone, led to a significantly higher reduction in pain intensity, in the neuropathic component, the degree of disability and TP dosage assumption. No serious side effects were observed.

Conclusion

Overall, the present findings suggest that um-PEA may be an innovative therapeutic intervention as add-on therapy to TP for the management of chronic LBP with a neuropathic component, as well as to improve patient quality of life. Additionally, this combination treatment allowed a reduction in TP dose over time and did not show any serious side effects.

     

NUMB-ing down cancer by more than just a NOTCH

The protein Numb does not live up to its name. This passive-sounding protein is anything but spent. Originally identified as a cell-fate determinant in Drosophila development, Numb received a good deal of attention as an inhibitor of the Notch receptor signaling pathway. It turns out, however, that Numb does a lot more than simply regulate Notch. It has been implicated in a variety of biochemical pathways connected with signaling (it regulates Notch-, Hedgehog- and TP53-activated pathways), endocytosis (it is involved in cargo internalization and recycling), determination of polarity (it interacts with the PAR complex, and regulates adherens and tight junctions), and ubiquitination (it exploits this mechanism to regulate protein function and stability). This complex biochemical network lies at the heart of Numb's involvement in diverse cellular phenotypes, including cell fate developmental decisions, maintenance of stem cell compartments, regulation of cell polarity and adhesion, and migration. Considering its multifaceted role in cellular homeostasis, it is not surprising that Numb has been implicated in cancer as a tumor suppressor. Our major goal here is to explain the cancer-related role of Numb based on our understanding of its role in cell physiology. We will attempt to do this by reviewing the present knowledge of Numb at the biochemical and functional level, and by integrating its apparently heterogeneous functions into a unifying scenario, based on our recently proposed concept of the "endocytic matrix". Finally, we will discuss the role of Numb in the maintenance of the normal stem cell compartment, as a starting point to interpret the tumor suppressor function of Numb in the context of the cancer stem cell hypothesis.     

2,3,7,8-Tetrachlorodibenzo-p-dioxin impairs iron homeostasis by modulating iron-related proteins expression and increasing the labile iron pool in mammalian cells

Cellular iron metabolism is essentially controlled by the binding of cytosolic iron regulatory proteins (IRP1 or IRP2) to iron-responsive elements (IREs) located on mRNAs coding for proteins involved in iron acquisition, utilization and storage. The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is one of the most potent toxins of current interest that occurs as poisonous chemical in the environment. TCDD exposure has been reported to induce a broad spectrum of toxic and biological responses, including significant changes in gene expression for heme and iron metabolism associated with liver injury. Here, we have investigated the molecular effects of TCDD on the iron metabolism providing the first evidence that administration of the toxin TCDD to mammalian cells affects the maintenance of iron homeostasis. We found that exposure of Madin-Darby Bovine Kidney cell to TCDD caused a divergent modulation of IRP1 and IRP2 RNA-binding capacity. Interestingly, we observed a concomitant IRP1 down-regulation and IRP2 up-regulation thus determining a marked enhancement of transferrin receptor 1 (TfR-1) expression and a biphasic response in ferritin content. The changed ferritin content coupled to TfR-1 induction after TCDD exposure impairs the cellular iron homeostasis, ultimately leading to significant changes in the labile iron pool (LIP) extent. Since important iron requirement changes occur during the regulation of cell growth, it is not surprising that the dioxin-dependent iron metabolism dysregulation herein described may be linked to cell-fate decision, supporting the hypothesis of a central connection among exposure to dioxins and the regulation of critical cellular processes. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.