An "artificial tongue" for calibrating solution flow characteristics of taste stimulus delivery systems

An "artificial tongue" is described which can be used to calibratethe stimulus delivery characteristics of flow systems for liquidtaste stimuli. The calibrator, which functions on the basisof conductance measurements, is used to ascertain the behaviourof certain test solutions in the flow system. The test solutionsare so prepared that they mimic the hydraulic properties ofthe stimulus solutions to be used. The special apparatus requiredis neither complex nor costly, and the procedures involved arestraightforward.     

Intrinsic competition between two European egg parasitoids of the brown marmorated stink bug

Following the accidental introduction and spread of the invasive polyphagous agricultural pest Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), the two European egg parasitoids Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae) and Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae) have been investigated for inundative biological control. Since the competititve outcome between the two generalist parasitoids is difficult to predict, intrinsic competition was investigated with a time-course development study. Both species readily oviposited in H. halys eggs containing eggs and early instar larvae of the competitor, but oviposition decreased when eggs contained late instar larvae and pupae. Ooencyrtus telenomicida offspring emergence from multiparasitized eggs was significantly lower than that from rearing controls, independent of the order of parasitization. Anastatus bifasciatus offspring emergence was not influenced by the presence of O. telenomicida when it parasitized as the first species, but emergence was decreased after oviposition in eggs containing O. telenomicida larvae and pupae. There was no indication that O. telenomicida can act as a facultative hyperparasitoid of A. bifasciatus. These results suggest that A. bifasciatus is the superior intrinsic competitor and no or minor negative implications for A. bifasciatus are expected if released in combination with O. telenomicida.     

The behaviour of deoxyhexose trihaloacetimidates in selected glycosylations

Armed deoxyhexose glycosyl donors are very reactive and sometimes too uncontrollably activated in glycosylation reactions; yields can be thereby reduced, especially when unreactive glycosyl acceptors are involved. In this paper, the behaviour of a range of deoxyhexose trihaloacetimidate (trichloro- and N-phenyl trifluoro-) donors is compared in some selected glycosylations towards biologically relevant targets. The selected N-phenyl trifluoroacetimidates often afforded best results in terms of both donor synthesis and glycosylation yield.     

The O-chain structure from the LPS of the bacterium Naxibacter alkalitolerans YIM 31775T

The O-chain polysaccharide of the lipopolysaccharide from the bacterium Naxibacter alkalitolerans strain YIM 31775(T) was characterized. The structure was studied by means of chemical analysis and 2D NMR spectroscopy and shown to be built up by the following tetrasaccharide repeating unit: -->3)-alpha-D-FucpNAc-(1-->2)-beta-D-Quip3NHBu-(1-->2)-alpha-D-Rhap-(1-->)-beta-D-Galp-(1--> where HBu is hydroxy-butanoyl.     

Nef-induced CD4 degradation: a diacidic-based motif in Nef functions as a lysosomal targeting signal through the binding of beta-COP in endosomes

The Nef protein of primate lentiviruses downregulates the cell surface expression of CD4 through a two-step process. First, Nef connects the cytoplasmic tail of CD4 with adaptor protein complexes (AP), thereby inducing the formation of CD4-specific clathrin-coated pits that rapidly endocytose the viral receptor. Second, Nef targets internalized CD4 molecules for degradation. Here we show that Nef accomplishes this second task by acting as a connector between CD4 and the beta subunit of COPI coatomers in endosomes. A sequence encompassing a critical acidic dipeptide, located nearby but distinct from the AP-binding determinant of HIV-1 Nef, is responsible for beta-COP recruitment and for routing to lysosomes. A novel class of endosomal sorting motif, based on acidic residues, is thus revealed, and beta-COP is identified as its downstream partner.     

Mitochondrial Ca2+ homeostasis in health and disease

Although it has long been known that mitochondria possess a complex molecular repertoire for accumulating and releasing Ca2+, only in recent years has a large body of data demonstrated that these organelles promptly respond to Ca(2+)-mediated cell stimulations. In this contribution, we will review the principles of mitochondrial Ca2+ homeostasis and its signaling role in different physiological and pathological conditions.     

Black tea extract supplementation decreases oxidative damage in Jurkat T cells

The purpose of this study was to investigate the protective effect of black tea (BT) extract against induced oxidative damage in Jurkat T-cell line. Cells supplemented with 10 or 25 mg/L BT were subjected to oxidation with ferrous ions. Malondialdehyde (MDA) production as marker of lipid peroxidation, DNA single strand breaks as marker of DNA damage, and modification of the antioxidant enzyme activity, glutathione peroxidase (GPX) were measured. Results show the efficacy of BT polyphenols to decrease DNA oxidative damage and to affect GPX activity (P<0.05), while no effect was shown on MDA production. The succeeding investigation of the activity of caffeine and epigallocatechin gallate demonstrated their antioxidant potential with respect to the cellular markers evaluated. In conclusion, this study supports the protective effect of BT against ferrous ions induced oxidative damage to DNA and the ability of BT to affect the enzyme antioxidant system of Jurkat cells.