Effects of Protamine Sulfate on Dengue Type 1 Viral Activities

Protamine treatment of type 1 dengue-infected mouse brain suspension resulted in precipitation of several viral specific activities. Complement-fixation activity was almost completely precipitated by protamine. The complement-fixation components recovered in the precipitate were comparable to a non-precipitated reference dengue 1 antigen in their homologous and heterologous reactions. Dengue hemagglutinin was also precipitated by the same treatment. The precipitated hemagglutinin was resolved into three components by buoyant density centrifugation, whose densities were 1.236, 1.215, and 1.178 g/ml, respectively. Three similar HA components were detected in non-protamine treated virus preparations. In both instances the highest-titered HA fraction possessed a buoyant density of 1.21–1.22 g/ml. These HA components were tested in the hemagglutination-inhibition reaction and were proved to be virus-specific. Cesium chloride density gradient centrifugation was shown to be useful for removing possible inhibitor(s) of viral specific hemagglutinin.     

MAJOR CLADES OF THE ANGIOSPERMS

Abstract— Our knowledge of fundamental angiosperm interrelationships is still very incomplete. The absence of a narrowly circumscribed gymnosperm outgroup, ideally the sister group, makes character evaluation, necessary for a cladistic analysis, difficult. According to current views the superorder Magnoliiflorae with a number of other groups, for example the monocotyledons, may represent a complex of families near the base of the angiosperms. Interrelationships of groups within the monocotyledons are much better understood than those between groups within the dicotyledons. A cladogram of monocotyledon orders based on earlier work by R. Dahlgren, H. T. Clifford, and F. N. Rasmussen is presented. A data matrix for a sample of the angiosperms with 61 characters for 49 taxa, mostly magnoliifloran and related families, is presented. The characters are polarized mainly according to the current view that the primitive angiosperm morphotype is a woody dicotyledon with strobiloid flowers. As an alternative the matrix is adjusted following W. C. Burger's conjecture that the primitive angiosperm was a herbaceous monocotyledon with trimerous flowers. Both matrices were run in a computerized parsimony analysis, resulting in numerous equally parsimonious solutions. This result is illustrative of the great homoplasy in the available character information, and also of how little actually is known about fundamental angiosperm interrelationships or phylogeny.     

Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution

In order to study the relationships among mammalian alpha-globin genes, we have determined the sequence of the 3' flanking region of the human alpha 1 globin gene and have made pairwise comparisons between sequenced alpha-globin genes. The flanking regions were examined in detail because sequence matches in these regions could be interpreted with the least complication from the gene duplications and conversions that have occurred frequently in mammalian alpha-like globin gene clusters. We found good matches between the flanking regions of human alpha 1 and rabbit alpha 1, human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and horse alpha 1 and goat II alpha. These matches were used to align the alpha-globin genes in gene clusters from different mammals. This alignment shows that genes at equivalent positions in the gene clusters of different mammals can be functional or nonfunctional, depending on whether they corrected against a functional alpha-globin gene in recent evolutionary history. The number of alpha-globin genes (including pseudogenes) appears to differ among species, although highly divergent pseudogenes may not have been detected in all species examined. Although matching sequences could be found in interspecies comparisons of the flanking regions of alpha- globin genes, these matches are not as extensive as those found in the flanking regions of mammalian beta-like globin genes. This observation suggests that the noncoding sequences in the mammalian alpha-globin gene clusters are evolving at a faster rate than those in the beta-like globin gene clusters. The proposed faster rate of evolution fits with the poor conservation of the genetic linkage map around alpha-globin gene clusters when compared to that of the beta-like globin gene clusters. Analysis of the 3' flanking regions of alpha-globin genes has revealed a conserved sequence approximately 100-150 bp 3' to the polyadenylation site; this sequence may be involved in the expression or regulation of alpha-globin genes.      

P48-Triggered transmembrane signaling transduction of human monocytes:mobilization of calcium ion and activation of protein kinase C(PKC)

INTRODUCTI0NThedifferentiati0nofcelIsalongthemonocyte-macr0phagepathwayandthesig-nalsinvo1vedinthesecel1sacquiringtheabilitytokilltum0rcellsarenotfllllyundersto0d.Wehavebeenstudingamoleculewhichappearst0beanimportantmemberofthecytokinenetworkinvo1vedintheregulati0nmonocyteactivation.ThiscytokinetermedP48wasisolatedfr0mthehllmannullcellleukemiacell1ineReh.IthasbeenpurifiedtohomogeneityandfOundtobedistinctfrominterferongamma,col0nystimulatingfactors(CSFs)andTNFalphaalldbeta[1,2].Func-ti…     

Oligonucleotide fingerprints of RNA species obtained from rhabdoviruses belonging to the vesicular stomatitis virus subgroup.

The relationships among the genomes of various rhabdoviruses belonging to the vesicular stomatitis virus subgroup were analyzed by an oligonucleotide fingerprinting technique. Of 10 vesicular stomatitis viruses, Indiana serotype (VSV Indiana), obtained from various sources, either no, few, or many differences were observed in the oligonucleotide fingerprints of the 42S RNA species extracted from standard B virions. Analyses of the oligonucleotides obtained from RNA extracted from three separate preparations of VSV Indiana defective T particles showed that their RNAs contain fewer oligonucleotides than the corresponding B particle RNA species. The fingerprints of RNA obtained from five VSV New Jersey serotype viruses were easily distinguished from those of the VSV Indiana isolates. Three of the VSV New Jersey RNA fingerprints were similar to each other but quite different from those of the other two viruses. The RNA fingerprints of two Chandipura virus isolates (one obtained from India and one from Nigeria) were also unique, whereas the fingerprint of Cocal virus RNA was unlike that of the serologically related VSV Indiana.     

Formation of recombinants between snowshoe hare and La Crosse bunyaviruses.

Wild-type recombinants were obtained at high frequency from coinfections of BHK cells involving temperature-sensitive, conditional-lethal mutants of snowshoe hare (SSH) and La Crosse (LAC) bunyaviruses. Analyses of two of the recombinants indicated that they have the genome compositions SSH/LAC/SSH and SSH/LAC/LAC for their respective L, M, and S virion RNA species. This evidence, together with that for the genetic stability of the recombinants, indicates that they were derived by segment reassortment of the competent genome pieces of the parental viruses. The SSH/LAC/SSH recombinant appears, from polypeptide analysis, to have the SSH type of nucleocapsid protein (N), whereas the SSH/LAC/LAC recombinant has the LAC nucleocapsid protein, suggesting that the viral S RNA codes for the N protein.     

Performance of a new dynamic model for predicting diurnal time courses of stomatal conductance at the leaf level

Under natural conditions, plants are subjected to continuous changes of irradiance that drive variations of stomatal conductance to water vapour (g_s). We propose a dynamic model to predict the temporal response of g_s at the leaf level using an asymmetric sigmoid function with a unique parameter describing time constants for increasing and decreasing g_s. The model parameters were adjusted to observed data using Approximate Bayesian Computation. We tested the model performance for (1) instant changes of irradiance; or (2) continuous and controlled variations of irradiance simulating diurnal time courses. Compared with the two mostly used steady‐state models, our dynamic model described daily time courses of g_s with a higher accuracy. In particular, it was able to describe the hysteresis of g_s responses to increasing/decreasing irradiance and the resulting rapid variations of intrinsic water‐use efficiency. Compared to the mechanistic model of temporal responses of g_s by Kirschbaum, Gross & Pearcy, for which time constants were estimated with a large variance, our model estimated time constants with a higher precision. It is expected to improve predictions of water loss and water‐use efficiency in higher scale models by using a small number of parameters.     

Rapid accumulation of phosphatidylinositol 4,5-bisphosphate and inositol 1,4,5-trisphosphate correlates with calcium mobilization in salt-stressed arabidopsis

The phosphoinositide phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] is a key signaling molecule in animal cells. It can be hydrolyzed to release 1,2-diacyglycerol and inositol 1,4,5-trisphosphate (IP(3)), which in animal cells lead to protein kinase C activation and cellular calcium mobilization, respectively. In addition to its critical roles in constitutive and regulated secretion of proteins, PtdIns(4,5)P(2) binds to proteins that modify cytoskeletal architecture and phospholipid constituents. Herein, we report that Arabidopsis plants grown in liquid media rapidly increase PtdIns(4,5)P(2) synthesis in response to treatment with sodium chloride, potassium chloride, and sorbitol. These results demonstrate that when challenged with salinity and osmotic stress, terrestrial plants respond differently than algae, yeasts, and animal cells that accumulate different species of phosphoinositides. We also show data demonstrating that whole-plant IP(3) levels increase significantly within 1 min of stress initiation, and that IP(3) levels continue to increase for more than 30 min during stress application. Furthermore, using the calcium indicators Fura-2 and Fluo-3 we show that root intracellular calcium concentrations increase in response to stress treatments. Taken together, these results suggest that in response to salt and osmotic stress, Arabidopsis uses a signaling pathway in which a small but significant portion of PtdIns(4,5)P(2) is hydrolyzed to IP(3). The accumulation of IP(3) occurs during a time frame similar to that observed for stress-induced calcium mobilization. These data also suggest that the majority of the PtdIns(4,5)P(2) synthesized in response to salt and osmotic stress may be utilized for cellular signaling events distinct from the canonical IP(3) signaling pathway.     

Directed discovery of bivalent peptide ligands to an SH3 domain

The Caenorhabditis elegans SEM-5 SH3 domains recognize proline-rich peptide segments with modest affinity. We developed a bivalent peptide ligand that contains a naturally occurring proline-rich binding sequence, tethered by a glycine linker to a disulfide-closed loop segment containing six variable residues. The glycine linker allows the loop segment to explore regions of greatest diversity in sequence and structure of the SH3 domain: the RT and n-Src loops. The bivalent ligand was optimized using phage display, leading to a peptide (PP-G(4)-L) with 1000-fold increased affinity for the SEM-5 C-terminal SH3 domain over that of a natural ligand. NMR analysis of the complex confirms that the peptide loop segment is targeted to the RT and n-Src loops and parts of the beta-sheet scaffold of this SH3 domain. This binding region is comparable to that targeted by a natural non-PXXP peptide to the p67(phox) SH3 domain, a region not known to be targeted in the Grb2 SH3 domain family. PP-G(4)-L may aid in the discovery of additional binding partners of Grb2 family SH3 domains.