Math, science, history, unraveling the mystery—That all started with de novo!

ALL physicists and chemists, with many who, though less directly, are yet no less deeply interested in the subjects opened up by the study of the phenomena of the discharge tube, will rejoice that Sir J. J. Thomson has found time, amid his many preoccupations, to bring out this second edition of his well-known monograph on rays of positive electricity. The output of scientific work is now so enormous that it is difficult to keep pace with it even in one's own special line of study. It would be practi cally impossible, if it were not for the assistance given by books such as this, ever to come abreast once more of a subject in which one has once fallen behind. In writing this clear and authoritative account of the present state of a subject which he has done so much to develop, Sir J. J. Thomson has performed a real service to science. Rays of Positive Electricity and their Application to Chemical Analyses. By Sir J. J. Thomson. (Monographs on Physics.) Second edition. Pp. x+237+ix pl. (London: Longmans, Green and Co., 1921.) 16s. net.

The discharge of electricity through gases is a subject that has had a most wonderful growth, — a growth possibly greater than that of any other single division in physics. With the discovery of cathode rays, X-rays, radioactivity, and rays of positive electricity, a new era was begun. The cathode rays were the first of the above to be brought to our attention, however, but little was known of their properties until the researches of the last decade. About fifteen years ago the wonderful X- or Roentgen rays were discovered. A few years later came that almost revolutionizing discovery of radioactivity, — revolutionizing because we are obliged to change our conceptions regarding the molecule and atom. Another of equal importance because of its bearing upon chemical composition, is afforded by J. J. Thomson's recent investigations on rays of positive electricity.

Shapes of MHC Restriction

The Escherichia coli periplasmic chaperone and peptidyl-prolyl isomerase (PPIase) SurA facilitates the maturation of outer membrane porins. Although the PPIase activity exhibited by one of its two parvulin-like domains is dispensable for this function, the chaperone activity residing in the non-PPIase regions of SurA, a sizable N-terminal domain and a short C-terminal tail, is essential. Unlike most cytoplasmic chaperones SurA is selective for particular substrates and recognizes outer membrane porins synthesized in vitro much more efficiently than other proteins. Thus, SurA may be specialized for the maturation of outer membrane proteins. We have characterized the substrate specificity of SurA based on its natural, biologically relevant substrates by screening cellulose-bound peptide libraries representing outer membrane proteins. We show that two features are critical for peptide binding by SurA: specific patterns of aromatic residues and the orientation of their side chains, which are found more frequently in integral outer membrane proteins than in other proteins. For the first time this sufficiently explains the capability of SurA to discriminate between outer membrane protein and non-outer membrane protein folding intermediates. Furthermore, peptide binding by SurA requires neither an active PPIase domain nor the presence of proline, indicating that the observed substrate specificity relates to the chaperone function of SurA. Finally, we show that SurA is capable of associating with the outer membrane. Together, our data support a model in which SurA is specialized to interact with non-native periplasmic outer membrane protein folding intermediates and to assist in their maturation from early to late outer membrane-associated steps.

The adsorption behaviors of amino acids in short chain peptides were examined. Each amino acid, aliphatic or charged, was inserted between the two tryptophans of a peptide, GWWG. The capacity factors of these peptides on an Ocytl-Sepharose column were measured. The adsorption enthalpies, entropies, and the number of repelled water molecules after adsorption were estimated to analyze the contribution of each different amino acid to its hydrophobic adsorption. The peptides inserted with aliphatic amino acids owned the highest capacity factors but released the least amount of adsorption heat among all the peptides under examination. It was found that the hydrophobic contribution of aliphatic amino acids was derived from the entropy gain by repelling the ordered water surrounding them. The insertion of negatively charged amino acids greatly reduced the capacity factors but still repelled a significant number of water molecules after adsorption. This indicated that the water molecules surrounding ionic amino acids were not orderly aligned. The dehydration cost energy but the water repelling did not offer enough entropy to drive the adsorption. Subsequently, lower retention was obtained from the peptides inserted with negatively charged ionic amino acids. The insertion of lysine increased the adsorption enthalpy but repelled no water molecules after adsorption. It was speculated that the inserted lysine still interacted with hydrophobic ligands but disturbed the interaction between ligands and adjacent tryptophans. Therefore, the adsorption enthalpy increased and the capacity factors decreased. Different amino acids contributed to hydrophobic interaction in different ways. The simultaneous analysis of capacity factor, adsorption enthalpy, adsorption entropy, and the number of repelled water molecules facilitated the understanding of the adsorption processes.

Sweet google O’ mine—The importance of online search engines for MS-facilitated, database-independent identification of peptide-encoded book prefaces: A EUPA YPIC challenge entry

Four steers, average body weight 260±15 kg, fitted with portal catheters were used in a 4×4 Latin Square design to evaluate the influence of dietary protein degradability in the rumen on peptide and amino acid fluxes across the gastrointestinal tract. Dietary protein degradability was regulated by using different protein sources and the diets were calculated to contain 130 g CP/kg and 9·62 MJ ME per kg DM. Plasma concentrations of amino acids were analysed before and after acid hydrolysis of samples first subjected to chemical deproteinization and physical ultrafiltration, and peptide amino acids (PAA) were calculated as the difference between total and free amino acids (FAA). Portal blood flow and arterial concentrations of FAA and PAA were not affected by protein degradability or by diet. Venoarterial concentration difference and net portal flux of FAA tended to increase (P < 0·10) with increase of degradable protein intake. Portal-arterial concentration difference (P < 0·05) and net portal flux (P < 0·10) of PAA increased linearly as dietary protein degradability increased. The proportion of PAA in total amino acid (FAA+PAA) net flux was not modified by dietary protein degradability or by diet, and the mean value as a proportion was 0·32. The major PAA absorbed were glutamate, leucine, aspartate and lysine for all diets, accounting in total for 0·50 of PAA flux. The results demonstrate that PAA may contribute significantly to AA flux across the portal-drained viscera (PDV) of steers, and both FAA and PAA net fluxes can be affected by degradable protein intake.

SummaryThis paper reports the influence of yeast strain, immobilisation and ageing time on the free amino acids and amino acids in peptides of sparkling wine made by the traditional method from the Emir grape variety over a period of 365 days in vintages 2004 and 2005. Four sparkling wines were obtained from the same base wine using yeast strains (both immobilised and free Saccharomyces bayanus and Saccharomyces oviformis). The analysis of variance and cluster revealed that there were significant differences between free amino acids and amino acids in peptides due to ageing time. However, the yeast strain affected most of the free amino acids and amino acids in peptides in only the 2004 vintage. The total amount of free amino acids was higher in the wine made with the S. oviformis compared to S. bayanus. Furthermore, there were no significant differences between the use of immobilised and free yeast in cases of free amino acids and amino acids in peptides.

In this study, the influence of yeast strain, immobilisation, and ageing time with yeast were examined in relation to the amount of free amino acids and amino acids in the peptides of wines. Free and immobilised Saccharomyces bayanus and Saccharomyces cerevisiae yeasts were used in sparkling wine production. Samples from the base wine and sparkling wines were taken at 20, 40, 90, 180, 270 and 365 days of ageing with yeast. It was observed that the majority of differences between wine samples in terms of the amount of free amino acids and amino acids in peptides were due to ageing time. The amount of total free amino acids in wine made with Saccharomyces cerevisiae was higher than in that made with Saccharomyces bayanus. In addition, no differences were observed between free and immobilised yeast in terms of amino acids and amino acids in peptides.

The urokinase-type plasminogen activator receptor (uPAR) sustains cell migration through its capacity to promote pericellular proteolysis, regulate integrin function, and mediate chemotactic signaling in response to urokinase. We have characterized the early signaling events triggered by the Ser-Arg-Ser-Arg-Tyr (SRSRY) chemotactic uPAR sequence. Cell exposure to SRSRY peptide promotes directional migration on vitronectin-coated filters, regardless of uPAR expression, in a specific and dose-dependent manner, with maximal effect at a concentration level as low as 10 nm. A similar concentration profile is observed in a quantitative analysis of SRSRY-dependent cytoskeletal rearrangements, mostly consisting of filamentous structures localized in a single cell region. SRSRY analogues with alanine substitutions fail to drive F-actin formation and cell migration, indicating a critical role for each amino acid residue. As with ligand-dependent uPAR signaling, SRSRY stimulates protein kinase C activity and results in ERK1/2 phosphorylation. The involvement of the high affinity N-formyl-Met-Leu-Phe receptor (FPR) in this process is indicated by the finding that 100 nm N-formyl-Met-Leu-Phe inhibits binding of D2D3 to the cell surface, as well as SRSRY-stimulated cell migration and F-actin polarization. Moreover, cell exposure to SRSRY promotes FPR-dependent vitronectin release and increased uPAR.alphavbeta5 vitronectin receptor physical association, indicating that alphavbeta5 activity is regulated by the SRSRY uPAR sequence via FPR. Finally, we provide evidence that alphavbeta5 is required for SRSRY-dependent ERK1/2 phosphorylation, whereas it is not required for protein kinase C activation. The data indicate that the ability of uPAR to stimulate cell migration and cytoskeletal rearrangements is retained by the SRSRY peptide alone and that it is supported by cross-talk between FPR and alphavbeta5.

Rays of positive electricity and their application to chemical analyses. By Sir J. J. Thomson, O. M. F.R.S. Second edition. Pp. x + 237. London: Longmans, Green and Co., 1921. Price 16s.

The 2007 Benjamin Franklin Medal in Chemistry Presented to Klaus Biemann, Ph.D., of The Massachusetts Institute of Technology Cambridge, Massachusetts

<i>Rays of Positive Electricity and their Application to Chemical Analysis</i> . By Sir J. J. Thomson. Longmans, Green &amp; Co. 1913. Pp. vi+132. Price, $1.40

<i>Rays of Positive Electricity and their Application to Chemical Analysis</i> . By Sir J. J. Thomson. Longmans, Green &amp; Co. 1913. Pp. vi+132. Price, $1.40

Rays of Positive Electricity and their Application to Chemical Analysis. By SIR J. J. THOMSON. Longmans, Green &amp; Co. 1913. Pp. vi+132. Price, $1.40