Vaccination with the immediate-early protein ICP47 of herpes simplex virus-type 1 (HSV-1) induces virus-specific lymphoproliferation, but fails to protect against lethal challenge

Assessing the immunobiological function of the individual proteins of herpes simplex virus-type 1 (HSV-1) continues to be important in elucidating virus-host interactions and for the rational design of subunit vaccines. In this report, the non-structural, immediate-early protein ICP47 of HSV-1 was examined for its ability to induce virus-specific immune responses. The ICP47 protein, when expressed from a recombinant vaccinia virus or when produced by cell-free, in vitro translation, induced a vigorous HSV-1-specific lymphoproliferative response. However, other common parameters of immunity such as neutralizing antibody, delayed-type hypersensitivity, and class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) were not induced by ICP47. Moreover, mice immunized with vaccinia-expressed ICP47 were unable to survive lethal challenge with virulent HSV, indicating that in spite of its ability to induce significant HSV-1-specific lymphoproliferation, ICP47 appears unable to afford protective immunity in vivo. Possible reasons for this failure and the implications of these results in terms of vaccine design are discussed.

Molecular characterization of gangliotetraosylceramide (GA1) in normal human brain and its developmental change

Several neutral glycosphingolipids have recently been purified from normal human brain to the criterion of migration as homogeneous bands in two different solvent systems. One of these has been permethylated and analyzed by gas chromatography. Stepwise specific exoglycosidase hydrolysis confirms its structure as GAl or Gal beta 1-->3GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->1Cer. The neutral glycosphingolipids of rat CNS have been examined in order to investigate changes in GA1 during critical ages of brain development. Employing the highly sensitive techniques of digoxigenin (DIG) immunostaining and Fluorescence Assisted Carbohydrate Electrophoresis (FACE), we have identified several previously uncharacterized long chain neutral glycosphingolipids in brain and myelin. A major band with Rf close to that of nLcOse5Cer purified from bovine erythrocytes has been identified as GA1 by immuno-TLC using mono-specific polyclonal anti-GA1 antisera. It appears in 5 day-postpartum (P5) developing brain, increases until 21 days (P21) and subsequently declines. This phasic change along with changes in other nonsialylated glycosphingolipids of the developing brain strongly suggests that GA1 and other neutral glycosphingolipids may play a mediator role(s) in brain development and/or myelinogenesis.

Cloning and sequencing of 5' flanking sequence from the gene encoding 2S storage protein, from two Brassica species

Using oligodeoxyribonucleotide primers and the polymerase chain reaction, we have cloned and sequenced about 1.2 kb of upstream sequences from two members of the 2S seed storage protein-encoding gene family from Brassica juncea and B. oleracea. The two sequences bear more than 90% homology and have characteristic seed-specific promoter motifs. The high degree of sequence conservation indicates that this napin-encoding gene family evolved earlier than the divergence of the three primary Brassica species and their amphidiploids, and the sequences have been conserved due to some metabolic constraints in seed development.

Improved bacterial hosts for regulated expression of genes from lambda pL plasmid vectors

The construction and use of a set of Escherichia coli strains with defective lambda prophages that facilitate expression of genes cloned in lambda pL-plasmid vectors is described. These bacteria allow high and regulated expression of such genes, whereas a kanamycin-resistance marker (KmR) on the prophage allows easy identification and genetic transfer from strain to strain. Optimal conditions for examining gene expression with the pL-vector systems using these strains are discussed.

Shuttle cosmid vectors for the trypanosomatid parasite Leishmania

We have developed two shuttle cosmid vectors for the trypanosomatid protozoan parasite Leishmania. Cosmids cLHYG and cLNEO contain hyg and neo markers, conferring resistance to hygromycin B and G418, respectively, replicate extrachromosomally after transfection into promastigotes, and bear a unique BamHI cloning site. To ensure the representation of telomeric sequences, which represent about 5% of the Leishmania genome, random insert DNAs were prepared by shearing followed by blunt-end ligation with BamHI adapters. Representative genomic libraries from Leishmania species representing the four major pathogenic complexes were prepared using cosmid cLHYG. The cosmid libraries were efficiently transfected into Leishmania, and individual cosmids were readily recovered by transformation back into Escherichia coli. The relatively small size of the Leishmania genome (50 Mb) combined with the capacity and transfection efficiency of these cosmid libraries (> 1000 Leishmania transfectants/plate) suggests the feasibility of functional genetic complementation in this parasite.

Design of helix ends. Amino acid preferences, hydrogen bonding and electrostatic interactions

The amino acid sequence and chemical interactions at the ends of 163 helices were surveyed so as better to understand amino acid preferences previously observed [Richardson, J.S. & Richardson, D.C. (1988) Science 240, 1648-1652]. Amino acid preferences differed from the previous survey in some significant details and in ways that might affect the choice of amino acids during the design of a protein helix. The following major conclusions about helix ends were deduced from additional patterns of amino acid occurrence and interactions that were observed. (1) A specific pair of hydrogen bonds is often observed between a glutamic acid (or glutamine) side chain at the N3 position and the N-cap amide hydrogen, and between the N-cap side chain (often threonine) and the N3 amide hydrogen. This reciprocal interaction may be an important means of stabilizing the N-terminal end of a helix. (2) Negatively charged amino acids (aspartic acid and glutamic acid) at the N-terminal end of helices may be more important in stabilizing protein helices than positively charged residues (chiefly lysine) at the C-terminal end. (3) The identity of the residue at the N-cap position is correlated with the backbone conformation at that position. (4) Aspartic acid (or asparagine) at the N2 or N3 position may adopt a conformation that suggests a hydrogen-bonding interaction with the end of the helix, especially when the N-cap side chain does not form a hydrogen bond with the end of the helix.

Serotonergic-cholinergic neurotransmitters' function in brain during cadmium exposure in protein restricted rat

Daily subcutaneous injection of cadmium chloride (0.3 mg/100g bw) for two weeks to normal and protein restricted (5% casein) rats shows significant decrease in 5-HT concentration in cerebellum, medulla oblongata-pons, hypothalamus, striatum-hippocampus, midbrain-thalamus-subthalamus, and cortex in both dietary regimens. No significant change occurs in concentration of ACh in cerebellum, but there is a significant increase in cortex, whereas significant decrease occurs in rest of the discrete regions of brain in both dietary conditions. Results also indicate that the intensity of cadmium effect is more evident in discrete brain regions in protein restricted dietary condition than in the normal group. The inhibitory action of Cd on both neurotransmitters has been discussed.

Biophysical characterization of Vibrio El Tor typing phage e5

Vibrio cholerae typing phage e5, which can lyse only the El Tor strains of V. cholerae, was characterized. The phage had a polyhedral head 51 nm in diameter and a short tail 13 nm in length. It contained 13 structural polypeptides, with the molecular mass of the major component being 50 kDa. Phage chromosome comprised a 38.5-kb linear double-stranded DNA molecule with unique termini, as determined by restriction fragment analysis and electron microscopy, and had a G+C content of 35.5%. A physical map was constructed with the restriction endonucleases HaeII and HpaII. Adsorption of the phage to its host followed a biphasic kinetics and its intracellular growth was characterized by a latent period of 15 min and a burst size of 100 particles per infected cell. The phage was found to be moderately thermotolerant.

Rolling-circle replication of a high-copy BPV-1 plasmid

We investigated the replicating form of a bovine papillomavirus type 1 (BPV-1) deletion mutant by direct electron-microscopic analysis of low molecular weight cellular DNA fractions. The detection of viral plasmid DNA replication intermediates was facilitated by the isolation of a spontaneously transformed mouse cell subclone containing an unusually high viral genome copy number (approx. 1000 per cell), and by employing a slight modification of the Hirt fractionation procedure to reduce the level of contaminating linear chromosomal DNA fragments. We observed exclusively rolling-circle-type viral DNA replication intermediates, at a frequency of detection of approximately one replication intermediate per 200 monomeric circular viral DNA molecules. The demonstration of rolling-circles with longer-than-genome-length tails indicated that this high-copy viral plasmid was not subject to a strict once-per-cell-cycle mode of DNA replication. Our observations provide further evidence in favour of an alternative replication mode of the BPV-1 genome, and may help to explain earlier conflicting findings concerning the mechanism of stable BPV-1 plasmid copy-number-control.

Benzene Forms Hydrogen Bonds with Water

Fully rotationally resolved spectra of three isotopic species of 1:1 clusters of benzene with water (H(2)O, D(2)O, and HDO) were fit to yield moments of inertia that demonstrate unambiguously that water is positioned above the benzene plane in nearly free internal rotation with both hydrogen atoms pointing toward the pi cloud. Ab initio calculations (MP2 level of electron correlation and 6-31 G(**) basis set with basis set superposition error corrections) predict a binding energy D(e) greater, similar 1.78 kilocalories per mole. In both the experimental and theoretical structures, water is situated nearly 1 angstrom within the van der Waals contacts of the monomers, a clear manifestation of hydrogen bond formation in this simple model of aqueous-pi electron interactions.

Ganglio-N-tetraosylceramide (GA1) of bovine and human brain. Molecular characterization and presence in myelin

During our studies of bovine brain neutral glycosphingolipids (Ngsl's), we have purified a compound that co-migrates on thin-layer chromatogram with standard GA1 (purified by acid hydrolysis of GM1) and close to penta- (nLc5Cer) glycosylceramide from bovien erythrocytes. The structure of the purified Ngsl from brain has been established by permethylation and by stepwise exoglycosidase hydrolysis. 600 MHz 1H NMR spectroscopy of the oligosaccharide obtained from the Ngsl after endoglycoceramidase hydrolysis confirms the structure as ganglio-N-tetraosylceramide (GgOse4Cer or GA1) as Gal beta 1----3GalNAc beta 1----4Gal beta 1----4Glc beta 1----1Cer. We have identified GA1 in bovine, rat and human brain and myelin by TLC-immunostaining with monospecific anti-GA1 antiserum.

Hypertonic stress induces alpha B-crystallin expression

Alpha B-crystallin, a major lens protein, was induced in primary cultures of dog lens epithelial cells and glomerular endothelial cells when they were grown under conditions of hypertonic stress. With Western blot analysis using a specific alpha B-crystallin antibody, we observed a significant increase in the concentration of alpha B-crystallin protein in cells grown for 4-6 days in media supplemented with 150 mM NaCl or 250 mM cellobiose. These supplements increased the osmolarity of the medium from 300 to 550-600 mosmol kg-1. Alpha B-crystallin mRNA was also increased reaching a maximum four-fold increase in lens and 16-fold increase in kidney cells within 1-2 days. These studies demonstrate a type of regulation of alpha B-crystallin expression in cells from lenticular and non-lenticular tissues.

Guaranteed convergence in a class of Hopfield networks

A class of symmetric Hopfield networks with nonpositive synapses and zero threshold is analyzed in detail. It is shown that all stationary points have a one-to-one correspondence with the minimal vertex covers of certain undirected graphs, that the sequential Hopfield algorithm as applied to this class of networks converges in at most 2n steps (n being the number of neurons), and that the parallel Hopfield algorithm either converges in one step or enters a two-cycle in one step. The necessary and sufficient condition on the initial iterate for the parallel algorithm to converge in one step are given. A modified parallel algorithm which is guaranteed to converge in [3n/2] steps ([x] being the integer part of x) for an n-neuron network of this particular class is also given. By way of application, it is shown that this class naturally solves the vertex cover problem. Simulations confirm that the solution provided by this method is better than those provided by other known methods.

Direct visualization of plasmid DNA in bacterial cells

The direct visualization of plasmid DNA inside Escherichia coli cells is demonstrated using phase-fluorescence microscopy of DAPI (4',6-diamidino-2-phenylindole)-stained bacteria. Small as well as large plasmids could be detected, both in minicells and in cells of larger size. For large plasmids, even single molecules appeared to be within the detection limit. The fluorescence generated from monomers of small plasmids was probably below this limit, and for these plasmids the observed signals may represent aggregates. The distribution of the fluorescence foci might reflect specific plasmid positioning during partition and/or replication.

Characterization of 2S seed storage protein of Brassica campestris and its antigenic homology with seed proteins of other Cruciferae

The low molecular weight seed storage protein of Brassica campestris has been isolated and its amino acid composition determined. Antibody raised against this low molecular weight protein has been used to compare the antigenic similarity between the low molecular weight storage proteins of different Cruciferae seeds by immunoprecipitation and Western blotting. These studies revealed the existence of antigenically homologous proteins of identical molecular weights in seeds of other Cruciferae but absent in some other dicots like mung bean and tobacco seeds.

Herpes simplex virus type 1-specific cytotoxic T lymphocytes recognize immediate-early protein ICP27

The identity of herpes simplex virus type 1 (HSV-1) antigens that serve as targets for cytotoxic T lymphocytes (CTL) and their ability to induce protective immunity remain uncertain. In this article, we report the identification of the immediate-early protein ICP27 as a CTL antigen in H-2d mice but not in H-2k or H-2b mice. Calculation of the frequencies of H-2d-restricted virus-specific CTL demonstrated that approximately one-fourth of the total HSV-1-specific response was directed against ICP27. To define the location of this CTL epitope, four truncated derivatives of the ICP27 gene which place the epitope in a 217-amino-acid region (amino acids 189 to 406) near the central portion of the protein were constructed. Mice immunized with ICP27 were able both to induce HSV-1-specific CTL and to survive a lethal intraperitoneal challenge with virulent HSV-1. However, neither appreciable antibody nor delayed-type hypersensitivity responses were induced in immunized mice, and they were also unable to clear a local epithelial virus challenge. It appears that ICP27, although capable of inducing several aspects of the immune response, is by itself unable to provide complete immunity.

The Escherichia coli cell cycle: one cycle or multiple independent processes that are co-ordinated?

In the life cycle of a bacterium there are several key processes: cellular growth, chromosome replication and decatenation, nucleoid partition, septum formation, and cell division. These processes have to be carefully controlled and co-ordinated both with respect to each other and to the growth of the cell, and could be viewed as parts of a single cycle in which each step is dependent upon the previous one. Alternatively, they could be independently controlled and carefully tuned to each other without actually constituting a true cycle. In this review, using Escherichia coli as model system, we discuss these two ways of describing the bacterial life cycle. The evidence supporting independent control of the processes is presented, and some of the key questions in the elucidation of the regulation of the bacterial life cycle are discussed.

The E. coli cell cycle and the plasmid R1 replication cycle in the absence of the DnaA protein

In E. coli strain EC::71CW chromosome replication is under the control of the R1 miniplasmid pOU71. A dnaA850::Tn10 derivative of EC::71CW was viable, which confirmed that R1 can replicate in the absence of the DnaA protein. The frequency of initiation of replication was, however, lowered and cell division was severely disturbed due to underreplication of the chromosome. Both replication and cell division could be restored to normal by increasing the production of RepA, the rate-limiting protein for initiation of replication from the integrated R1 origin. Therefore, the RepA protein seems to compensate for the absence of DnaA in the initiation of replication and assembly of replisomes. The role of the DnaA protein in the initiation of DNA replication, and as an overall regulator of the chromosome replication and cell division cycles of E. coli, is discussed in view of these results.

A disialoganglioside of the globo-series from chicken skeletal muscle

We have isolated a disialoganglioside of the globo-series from chicken pectoral muscle. The compound was obtained by extraction followed by ion-exchange and silicic acid column chromatography and judged to be pure by thin-layer chromatography in three solvent systems. The structure of the ganglioside was determined by carbohydrate and ceramide composition analysis, sequential exoglycosidase digestion, methylation analysis, and 500-MHz 1H-NMR spectroscopy to be: (formula; see text) Analysis of the ceramide moiety indicated d18:1 sphingosine as the long-chain base, and C16:0, C18:0, C18:1, and C20:0 as the prevalent fatty acids. This glycolipid is only the second ganglioside of the globo-series, and the first disialo member of the series, found in chicken muscle.

Biogenic amines and ascorbic acid in rat brain following steroid contraceptive treatment

Chronic treatment with steroid contraceptive produced a decrease in dopamine and norepinephrine concentration in discrete brain areas and an increase in ascorbic acid level. We suggest that alteration in the level of biogenic amines by steroid contraceptive may have some functional correlation with the ascorbic acid concentration in rat brain.