The influence of storage on the “chemical age” of red wines

Storage conditions and duration have a considerable influence on wine quality. Optimum temperature and humidity conditions may improve wine quality through ageing, while incorrect or excessively long storage leads to negative results. In order to evaluate the global effects of storage on red wine composition, 20 Sangiovese wines were stored in two different conditions (cellar or house) for a period of 2 years and analysed every 6 months. Untargeted LC–MS analysis showed various putative markers for the type and length of conservation (i.e. pigments, flavanols, pantothenic acid etc.), while targeted LC–MS confirmed and expanded these results within specific metabolic groups. The results of multivariate analysis showed that wines stored in the cellar changed little even after 2 years of storage, while wines stored in typical domestic conditions (house) developed approximately four times faster, reaching a composition similar to wines stored in the cellar for 2 years after just 6 months. The formation of several monosulfonated flavanols during domestic ageing provided the first evidence in wine of a reaction between wine tannins—both catechins and proanthocyanidins—and the exogenous antioxidant bisulfite. Moreover, ageing in domestic conditions appeared to induce an accelerated decrease in wine pigments, while specifically promoting the formation of pinotin A-like pigments and the hydrolysis of flavonol glycosides.     

The action of glutamate and the problem op the “extracellular space” in the retina

Summary Turtle's retinae were incubated in isotonic Ringer and then studied with the electron microscope in order to determine if in these conditions an extracellular space appeared. In the incubated retinae, as in the normal ones no extracellular space was observed. The distance between adjacent membranes is of 120–250 Å and is filled with a cementing material.The Müller cell of the turtle's retina is described. The existence, at the choroidal end of this cell, of villous projections filled with vesicles and the accumulation of mitochondria under these projections would suggest that a process of micropinocytosis takes place in this site, and that it may be metabolically more active. After incubation, Müller cells showed no appreciable changes, in contrast with what happens to astrocytes in incubated slices of CNS (Gerschenfeld et al. 1959).The addition of sodium-l-glutamate to the incubation medium determined a marked swelling of the nervous endings in the inner synaptic layer and a similar though less pronounced change in the ganglion cells. This would indicate that the surcharge of water, sodium and chloride produced by glutamate (Ames 1956) is localized in this layer.The selective action of glutamate on the inner synaptic layer, in contrast with the excellent preservation of the outer synaptic layer, is probably linked to differences in biochemistry and physiology of synapses in these two strata.Work supported by a research grant from the Air Force Office of Scientific Research (5–60), U.S.A.     

The structure of the α-keratin microfibril

Quantitative measurements of the intensity of the meridional reflections in the X-ray-diffraction pattern of alpha-keratin are shown to be consistent with a microfibril structure in which a surface lattice with an axially projected period around 200 A is subject to a periodic interruption with an axially projected period of 470 A. Taken in conjunction with recent evidence on the chemical structure of alpha-keratin and other intermediate filaments this finding enables an elaboration to be made of a model proposed earlier by RDB Fraser, TP MacRae, & E Suzuki (J. Mol. Biol. 108, 435-452, 1976) for the alpha-helical framework of the microfibril. The disposition and connectivity of the helical segments suggested here provides a straightforward explanation of a number of recent physicochemical and electron-microscopical observations on intermediate filaments and provides a starting point for the development of models for the framework of other intermediate filaments.     

The NMR solution structure and characterization of pH dependent chemical shifts of the β-elicitin, cryptogein

The NMR structure of the 98 residue -elicitin, cryptogein, which induces a defence response in tobacco, was determined using 15N and 13C/15N labelled protein samples. In aqueous solution conditions in the millimolar range, the protein forms a discrete homodimer where the N-terminal helices of each monomer form an interface. The structure was calculated with 1047 intrasubunit and 40 intersubunit NOE derived distance constraints and 236 dihedral angle constraints for each subunit using the molecular dynamics program DYANA. The twenty best conformers were energy-minimized in OPAL to give a root-mean-square deviation to the mean structure of 0.82 Å for the backbone atoms and 1.03 Å for all heavy atoms. The monomeric structure is nearly identical to the recently derived X-ray crystal structure (backbone rmsd 0.86 Å for residues 2 to 97) and shows five helices, a two stranded antiparallel -sheet and an -loop. Using 1H,15N HSQC spectroscopy the pKa of the N- and C-termini, Tyr12, Asp21, Asp30, Asp72, and Tyr85 were determined and support the proposal of several stabilizing ionic interactions including a salt bridge between Asp21 and Lys62. The hydroxyl hydrogens of Tyr33 and Ser78 are clearly observed indicating that these residues are buried and hydrogen bonded. Two other tyrosines, Tyr47 and Tyr87, show pKa's >12, however, there is no indication that their hydroxyls are hydrogen bonded. Calculations of theoretical pKa's show general agreement with the experimentally determined values and are similar for both the crystal and solution structures.     

“A stochastic solution of the 3-body problem in chemical kinetics. The termolecular stochastic process I”

It appears to be axiomatic that termolecular and higher order reactions occur relatively rarely. The basis for this judgment seems to lie in the supposition that successful 3-Body collisions of 3 interactive species of molecules cannot occur frequently enought to account for chemical or biochemical transformation. In order to provide a more complete mathematical framework than now exists for examining this hypothesis the probability of effective termolecular “δ-collisions” as a function of time is derived. This amounts to adding to the class of reactions for which stochastic models are now available the termolecular reaction. In common with the unimolecular and bimolecular cases this process is seen to satisfy the criterion of consistency-in-the-mean with respect to deterministic formulations. It is planned next to use the termolecular process and the lower order processes in computer-assistedin numero experimental studies aimed at comparing alternative mechanisms of reaction.     

The Sulfolobus-“Caldariella” group: Taxonomy on the basis of the structure of DNA-dependent RNA polymerases

The similarity of the morphology and of DNA composition, the homology of the component patterns of DNA-dependent RNA polymerases and their immunochemical crossreactivity support the conclusion that several extreme thermoacidophiles are related to each other. We name two new species of the genus Sulfolobus. The first, Sulfolobus solfataricus (DSM 1616 and DSM 1617) has the same GC content in its DNA and the same general properties as S. acidocaldarius, but differs significantly from the latter species in the molecular weights of the 11 components of its RNA polymerase and in the salt requirements of this enzyme. The second, Sulfolobus brierleyi, DSM 1651, differs from S. acidocaldarius in several respects. The cells show much less stability at neutral pH. The GC content is significantly lower. The RNA polymerase lacks two components present in the enzymes from the other species. The residual 9 components show larger size differences from the homologous subunits of the S. acidocaldarius enzyme.Like the enzyme from S. solfataricus, the polymerase from S. brierleyi yields an incomplete immunochemical crossreaction with an antibody against the RNA polymerase from S. acidocaldarius.The isolates DSM 1616 and DSM 1617 of Sulfolobus solfataricus are probably identical with or similar to the Caldariella strains MT 3 and MT 4, isolated by de Rosa et al. (1975).Like all other known archaebacterial RNA polymerases the enzymes from these species are insensitive to rifampicin and streptolydigin.Abbreviations G+C Guanine + Cytosine - HPLC High Performance Liquid Chromatography - S_AB Similarity coefficient between two different RNAs as defined by Fox et al. (1977) - SDS Sodium dodecylsulfate (Sodium laurylsulfate), SSC 0.15 M NaCl, 0.015 M Na Citrate pH 7.4     

The primary structure of the human ϵ-globin gene

We describe the complete nucleotide sequence of the human ?-globin gene including 387 nucleotides of 5′ flanking sequence and 301 nucleotides of 3′ flanking sequence. The arrangement of coding, noncoding and intervening sequences in this gene is entirely consistent with its identification as the embryonic β-like globin gene.     

Absence of “void area” in freeze-etched vesicles of the Alnus crispa var. mollis Fern. root nodule endophyte

Nitrogen-fixing root nodules of Alnus crispa var. mollis Fern. were studied by transmission electron microscopy and by freeze-etching technique. Ultrathin sectioning of septate vesicles of the actinomycetal endophyte showed an electron transparent zone, the so-called void area, between the vesicle cell wall and its encapsulation material. This void area was not observed in the freeze-etching replicas of cryoprotected nodular tissue. It is suggested that the void area is the result of the coming-off of the vesicle cell wall from the capsule and that its formation reflects difficulty in fixing the voluminous mature vesicle of the root nodule endophyte.