The role of disulfide bridges in the 3-D structures of the antimicrobial peptides gomesin and protegrin-1: a molecular dynamics study

Some antimicrobial peptides have a broad spectrum of action against many different kinds of microorganisms. Gomesin and protegrin-1 are examples of such antimicrobial peptides, and they were studied by molecular dynamics in this research. Both have a beta-hairpin conformation stabilized by two disulfide bridges and are active against Gram-positive and Gram-negative bacteria, as well as fungi. In this study, the role of the disulfide bridge in the maintenance of the tertiary peptide structure of protegrin-1 and gomesin is analyzed by the structural characteristics of these peptides and two of their respective variants, gomy4 and proty4, in which the four cysteines are replaced by four tyrosine residues. The absence of disulfide bridges in gomy4 and proty4 is compensated by overall reinforcement of the original hydrogen bonds and extra attractive interactions between the aromatic rings of the tyrosine residues. The net effects on the variants with respect to the corresponding natural peptides are: i) maintenance of the original beta-hairpin conformation, with great structural similarities between the mutant and the corresponding natural peptide; ii) combination of positive F and. Ramachandran angles within the hairpin head region with a qualitative change to a combination of positive (F) and negative (.) angles, and iii) significant increase in structural flexibility. Experimental facts about the antimicrobial activity of the gomesin and protegrin-1 variants have also been established here, in the hope that the detailed data provided in the present study may be useful for understanding the mechanism of action of these peptides.

Stochasticity favoring the effects of the R&D strategies of the firms

We present stochastic dynamics on the production costs of Cournot competitions, based on perfect Nash equilibria of nonlinear R&D investment strategies to reduce the production costs of the firms at every period of the game. We analyse the effects that the R&D investment strategies can have in the profits of the firms along the time. We observe that, in certain cases, the uncertainty can improve the effects of the R&D strategies in the profits of the firms due to the non-linearity of the profit functions and also of the R&D parameters.

An Empirical Examination of the R&D Boundaries of the Firm - A Problem-Solving Perspective

We consider, both theoretically and empirically, how different organization modes are aligned to govern the efficient solving of technological problems. The data set is a sample from the Chinese consumer electronics industry. Following mainly the problem solving perspective (PSP) within the knowledge based view (KBV), we develop and test several PSP and KBV hypotheses, in conjunction with competing transaction cost economics (TCE) alternatives, in an examination of the determinants of the R&D organization mode. The results show that a firm’s existing knowledge base is the single most important explanatory variable. Problem complexity and decomposability are also found to be important, consistent with the theoretical predictions of the PSP, but it is suggested that these two dimensions need to be treated as separate variables. TCE hypotheses also receive some support, but the estimation results seem more supportive of the PSP and the KBV than the TCE.

The number and profile of reactive NADH-d and NADPH-d neurons of myenteric plexus of six-month-old rats are different in the cecum portions

Whole-mount preparations were prepared and submitted to NADH-diaphorase and NADPH-diaphorase histochemistry techniques. The myenteric plexus arrangement and the number of neurons were comparatively evaluated among the different portions of the cecum. The neurons from the apical and basal regions were distributed in classes at intervals of 100µm², the means of the corresponding intervals being compared. The ganglia, in both techniques, were often connected by fine bundles, which became thicker in the mesenteric region and in the region next to the cecal ampulla. The number of positive NADH-d neurons was higher than that of NADPH-d neurons in all portions, from both regions. The numbers of reactive NADH-d e NADPH-d neurons were significantly different among the different portions of the cecum, except for the antimesenteric basal and intermediate basal regions, considering the NADH-d neurons. The profile area for the reactive NADH-d e NADPH-d neurons was higher in the apical region than in the basal area. Differences in arrangement, distribution and size of positive NADH-d e NADPH-d neurons in the different cecum portions evidenced the importance of the subdivision of the analyzed organ.

Letter and envelope addressed to Mr. Samuel D. Woodruff of St. Catharines

Letter and envelope addressed to Mr. Samuel D. Woodruff of St. Catharines. The envelope is postmarked St. Catharines, Dec. 31, 1887, Port Robinson, Dec. 31, 1887 and Welland, Dec. 31, 1887. The letter to S.D. Woodruff from Calvin Cudney and it says that he has enclosed $35 in interest, Dec. 29, 1887.

Almanac of S.D. Woodruff of St. Catharines

Almanac of S.D. Woodruff of St. Catharines (soft cover) containing records of items sold to various people, 1858-1866.

Envelope addressed to S.D. Woodruff of St. Catharines

Envelope addressed to S.D. Woodruff of St. Catharines and postmarked Jan. 2, 1886.

Letter on Long Point Company letterhead addressed to W.D. Woodruff of Lincoln Paper Mills

Letter on Long Point Company letterhead addressed to W.D. Woodruff of Lincoln Paper Mills, Merritton, Ontario in which Frank Reid, secretary of Long Point Company encloses a copy of the by-laws and the dates of incorporation, as requested (1 page, typed) [by-laws are not included here], Jan. 18, 1916.

List of inventory of goods in the dwelling of S.D. Woodruff of St. Catharines

List of inventory of goods (6 pages, handwritten) in the dwelling of S.D. Woodruff of St. Catharines. This list was examined by William Walker on Oct. 30, 1862 and compiled on Oct. 27, 1862.

Printed blank from the New York Central and Hudson River Railroad Express Freight Line, New York for shipping packages of brackets and racks to S.D. Woodruff of St. Catharines

Printed blank from the New York Central and Hudson River Railroad Express Freight Line, New York for shipping packages of brackets and racks to S.D. Woodruff of St. Catharines. This document is signed by R.L. Crawford, agent, Aug.11, 1876.

Letter to Mr. W.D. Woodruff of Lincoln Paper Mills, Merritton from P.J. Price of the United Gas Companies

Letter to Mr. W.D. Woodruff of Lincoln Paper Mills, Merritton from P.J. Price of the United Gas Companies, St. Catharines regarding a cheque received from E.J. McIntyre for $200. Included with this letter is an envelope addressed to W.D. Woodruff, Dec. 27, 1910.

Receipt from James D. Tait of St. Catharines for fabrics and trims

Receipt from James D. Tait of St. Catharines for fabrics and trims, Aug. 24, 1886.

Receipt from James D. Tait of St. Catharines for curtain and drapery materials

Receipt from James D. Tait of St. Catharines for curtain and drapery materials, Sept. 21, 1886.