bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complete Genome Sequence of Lymphocystis Disease Virus Isolated from China
Authors: Zhang Qi-Ya , Xiao Feng , Xie Jian , Li Zheng-Qiu , Gui Jian-Fang 
Published: June 2004

ABSTRACT

Lymphocystis diseases in fish throughout the world have been extensively described. Here we report the complete genome sequence of lymphocystis disease virus isolated in China (LCDV-C), an LCDV isolated from cultured flounder (
Paralichthys olivaceus
) with lymphocystis disease in China. The LCDV-C genome is 186,250 bp, with a base composition of 27.25% G+C. Computer-assisted analysis revealed 240 potential open reading frames (ORFs) and 176 nonoverlapping putative viral genes, which encode polypeptides ranging from 40 to 1,193 amino acids. The percent coding density is 67%, and the average length of each ORF is 702 bp. A search of the GenBank database using the 176 individual putative genes revealed 103 homologues to the corresponding ORFs of LCDV-1 and 73 potential genes that were not found in LCDV-1 and other iridoviruses. Among the 73 genes, there are 8 genes that contain conserved domains of cellular genes and 65 novel genes that do not show any significant homology with the sequences in public databases. Although a certain extent of similarity between putative gene products of LCDV-C and corresponding proteins of LCDV-1 was revealed, no colinearity was detected when their ORF arrangements and coding strategies were compared to each other, suggesting that a high degree of genetic rearrangements between them has occurred. And a large number of tandem and overlapping repeated sequences were observed in the LCDV-C genome. The deduced amino acid sequence of the major capsid protein (MCP) presents the highest identity to those of LCDV-1 and other iridoviruses among the LCDV-C gene products. Furthermore, a phylogenetic tree was constructed based on the multiple alignments of nine MCP amino acid sequences. Interestingly, LCDV-C and LCDV-1 were clustered together, but their amino acid identity is much less than that in other clusters. The unexpected levels of divergence between their genomes in size, gene organization, and gene product identity suggest that LCDV-C and LCDV-1 shouldn't belong to a same species and that LCDV-C should be considered a species different from LCDV-1.
Potent Neutralizing Serum Immunoglobulin A (IgA) in Human Immunodeficiency Virus Type 2-Exposed IgG-Seronegative Individuals
Authors: Lizeng Qin , Nilsson Charlotta , Sourial Samer , Andersson Sören , Larsen Olav , Aaby Peter , Ehnlund Mariethe , Björling Ewa 
Published: June 2004

ABSTRACTThe mechanisms behind the resistance to human immunodeficiency virus type 2 (HIV-2) infection are still not fully understood. In the present study, we explored the HIV-2-specific humoral serum immunoglobulin A (IgA) immune response in HIV-2-exposed IgG-seronegative (EGSN) individuals. Serum samples from heterosexual EGSN individuals and their known HIV-2-infected partners, as well as controls originating from Guinea-Bissau in Africa, were studied. Antibody reactivity to native and recombinant envelope glycoproteins was investigated, and the capacity of purified serum IgA to neutralize HIV-2SBL6669was tested. Our results showed that 16 of 25 EGSN samples exhibited reactivity against whole HIV-2 antigen, 6 of 25 samples reacted with recombinant gp36 (rgp36), and 3 of 25 samples were positive against HIV-2 rgp105; no reactivity to native HIV-2 gp125 was detected. Purified serum IgA antibodies from both EGSN and HIV-2-positive individuals, but not that from the negative controls, exhibited neutralization of HIV-2SBL6669. The most potent neutralization activity was exhibited by IgA purified from EGSN compared to infected individuals' IgA. The antigenic pattern of the HIV-2-positive partners showed that all serum IgA samples were reactive to whole HIV-2 antigen, and 14 of 15 reacted with rgp36. For rgp105 and gp125, 5 of 15 and 4 of 15 samples exhibited binding, respectively. The serum of the EGSN group had a higher mean IgA concentration than that of the negative controls (P< 0.05). Thus, we describe HIV-2-specific serum IgA antigen reactivity and show a more potent serum IgA-mediated HIV-2-neutralizing activity in EGSN individuals than in HIV-2-infected patients.
Antisense-Mediated Inhibition of Human Immunodeficiency Virus (HIV) Replication by Use of an HIV Type 1-Based Vector Results in Severely Attenuated Mutants Incapable of Developing Resistance
Authors: Lu Xiaobin , Yu Qiao , Binder Gwendolyn K. , Chen Ziping , Slepushkina Tatiana , Rossi John , Dropulic Boro 
Published: June 2004

ABSTRACT

We have constructed a human immunodeficiency virus type 1 (HIV-1)-based lentiviral vector expressing a 937-base antisense sequence against the HIV-1 envelope gene. Transduction of CD4
+
T lymphocytes with this vector results in expression of the therapeutic antisense sequence and subsequent inhibition of productive HIV-1 replication. In this report, we examined the effect of antisense-mediated suppression on the potential development of virus escape mutants using a permissive T-cell line cultured under conditions that over serial passages specifically allowed for generation and amplification of mutants selected for by antisense pressure. In the resulting virus clones, we found a significant increase in the number of deletions at the envelope target region (91% compared to 27.5% in wild-type HIV). Deletions were most often greater than 1 kb in length. These data demonstrate for the first time that during antisense-mediated suppression of HIV, mutants develop as a direct result of selective pressure on the HIV genomic RNA. Interestingly, in clones where deletions were not observed, there was a high rate of A-G transitions in mutants at the antisense target region but not outside this region, which is consistent with those mutations that are predicted as a result of antisense-mediated modification of double-stranded RNA by the enzyme double-stranded RNA-specific adenosine deaminase. These clones were not found to be escape mutants, as their replicative ability was severely attenuated, and they did not replicate in the presence of vector.
Sequencing-Based Detection of Low-Frequency Human Immunodeficiency Virus Type 1 Drug-Resistant Mutants by an RNA/DNA Heteroduplex Generator-Tracking Assay
Authors: Kapoor Amit , Jones Morris , Shafer R. W. , Rhee Soo-Yon , Kazanjian Powel , Delwart Eric L. 
Published: June 2004

ABSTRACTDrug-resistant viruses may be present as minority variants during early treatment failures or following discontinuation of failed antiretroviral regimens. A limitation of the traditional direct PCR population sequencing method is its inability to detect human immunodeficiency virus type 1 (HIV-1) variants present at frequencies lower than 20%. A drug resistance genotyping assay based on the isolation and DNA sequencing of minority HIV protease variants is presented here. A multiple-codon-specific heteroduplex generator probe was constructed to improve the separation of HIV protease genes varying in sequence at 12 codons associated with resistance to protease inhibitors. Using an RNA molecule as probe allowed the simple sequencing of protease variants isolated as RNA/DNA heteroduplexes with different electrophoretic mobilities. The protease gene RNA heteroduplex generator-tracking assay (RNA-HTA) was tested on plasma quasispecies from 21 HIV-1-infected persons in whom one or more protease resistance mutations emerged during therapy or following initiation of salvage regimens. In 11 of 21 cases, RNA-HTA testing of virus from the first episode of virologic failure identified protease resistance mutations not seen by population-based PCR sequencing. In 8 of these 11 cases, all of the low-frequency drug resistance mutations detected exclusively by RNA-HTA during the first episode became detectable by population-based PCR sequencing at the later time point. Distinct sets of protease mutations could be linked on different genomes in patients with high-frequency protease gene lineages. The enhanced detection of minority drug resistance variants using a sequencing-based assay may improve the efficacy of genotype-assisted salvage therapies.
Modulation of p53 Cellular Function and Cell Death by African Swine Fever Virus
Authors: Granja Aitor G. , Nogal María L. , Hurtado Carolina , Salas José , Salas María L. , Carrascosa Angel L. , Revilla Yolanda 
Published: June 2004

ABSTRACT

Modulation of the activity of tumor suppressor p53 is a key event in the replication of many viruses. We have studied the function of p53 in African swine fever virus (ASFV) infection by determining the expression and activity of this transcription factor in infected cells. p53 levels are increased at early times of infection and are maintained throughout the infectious cycle. The protein is transcriptionally active, stabilized by phosphorylation, and localized in the nucleus. p53 induces the expression of p21 and Mdm2. Strikingly, these two proteins are located at the cytoplasmic virus factories. The retention of Mdm2 at the factory may represent a viral mechanism to prevent p53 inactivation by the protein. The expression of apoptotic proteins, such as Bax or active caspase-3, is also increased following ASFV infection, although the increase in caspase-3 does not appear to be, at least exclusively, p53 dependent. Bax probably plays a role in the induction of apoptosis in the infected cells, as suggested by the release of cytochrome
c
from the mitochondria. The significance of p21 induction and localization is discussed in relation to the shutoff of cellular DNA synthesis that is observed in ASFV-infected cells.
An Exposed Domain in the Severe Acute Respiratory Syndrome Coronavirus Spike Protein Induces Neutralizing Antibodies
Authors: Zhou Tong , Wang Hong , Luo Danlin , Rowe Thomas , Wang Zheng , Hogan Robert J. , Qiu Shihong , Bunzel Robert J. , Huang Guoqiang , Mishra Vinod , Voss Thomas G. , Kimberly Robert , Luo Ming 
Published: June 2004

ABSTRACT

Exposed epitopes of the spike protein may be recognized by neutralizing antibodies against severe acute respiratory syndrome (SARS) coronavirus (CoV). A protein fragment (S-II) containing predicted epitopes of the spike protein was expressed in
Escherichia coli
. The properly refolded protein fragment specifically bound to the surface of Vero cells. Monoclonal antibodies raised against this fragment recognized the native spike protein of SARS CoV in both monomeric and trimeric forms. These monoclonal antibodies were capable of blocking S-II attachment to Vero cells and exhibited in vitro antiviral activity. These neutralizing antibodies mapped to epitopes in two peptides, each comprising 20 amino acids. Thus, this region of the spike protein might be a target for generation of therapeutic neutralizing antibodies against SARS CoV and for vaccine development to elicit protective humoral immunity.
Mitotic Chromosome-Binding Activity of Latency-Associated Nuclear Antigen 1 Is Required for DNA Replication from Terminal Repeat Sequence of Kaposi's Sarcoma-Associated Herpesvirus
Authors: Lim Chunghun , Choi Changtaek , Choe Joonho 
Published: June 2004

ABSTRACT
Latency-associated
nuclear antigen 1 (LANA1) of Kaposi's sarcoma-associated
herpesvirus (KSHV) is implicated in the persistence of the viral genome
during latent infection. It has been suggested that LANA1 tethers the
viral genome to the host chromosome and also participates actively in
DNA replication from the terminal repeat of KSHV. Here we show by
mutational analysis that the mitotic chromosome-binding activity of
LANA1 is tightly coupled to its replication activity. Thus, KSHV
appears to have evolved a unique tactic for its stable
maintenance.
Inhibition of Virus Production in JC Virus-Infected Cells by Postinfection RNA Interference
Authors: Orba Yasuko , Sawa Hirofumi , Iwata Hiroshi , Tanaka Shinya , Nagashima Kazuo 
Published: June 2004

ABSTRACT
RNA interference has been applied for the prevention of virus infections in mammalian cells but has not succeeded in eliminating infections from already infected cells. We now show that the transfection of JC virus-infected SVG-A human glial cells with small interfering RNAs that target late viral proteins, including agnoprotein and VP1, results in a marked inhibition both of viral protein expression and of virus production. RNA interference directed against JC virus genes may thus provide a basis for the development of new strategies to control infections with this polyomavirus.
ON THE USE OF A VISUAL CORTICAL SUB-BAND MODEL FOR INTERACTIVE HEURISTIC EDGE DETECTION
Authors: LYON DOUGLAS A. 
Published: June 2004

We present a novel interactive edge detection algorithm that combines A* search with low-level adaptive image processing. The algorithm models the semantically driven interpretation that we hypothesize to occur between the mind and visual cortex in the human brain. The basic idea is that oriented Gabor sub-bands are used to model grating cells in the mammalian visual system. These sub-bands are used during the search for a path to a marker in an image. A domain expert uses image markers to select edges of interest.We demonstrate the system in several image domains. Examples are shown in the areas of photo-interpretation, medical imaging, path planning and general edge finding. The A* search finds a suboptimal result, but executes in a time that is typically 10 to 1,000 times faster than the dynamic programming approach currently used for this type of edge detection.
Single-Crystal Magnetic Study on Guest-Tunable Weak Ferromagnets [M{N(CN)2}2(pyrimidine)](guest) (M = Fe, Co)
Authors: Takagami Naomi , Ishida Takayuki , Nogami Takashi 
Published: June 2004

Abstract
Low-temperature magnets derived from [M{N(CN)2}2(pm)] (M = FeII, CoII) have guest molecules incorporated in the clearance of the three-dimensional framework, where pm stands for pyrimidine. A pm molecule in [Fe{N(CN)2}2(pm)](pm) (1) was characterized as a guest by means of X-ray crystallographic analysis. The guest molecules as well as the host N(CN)2 skeletons are disordered in [Fe{N(CN)2}2(pm)](guest) (guest = EtOH (2), n-PrOH (3), 1/2 n-BuOH (4)) and also in [Co{N(CN)2}2(pm)](guest) (guest = EtOH (5), n-PrOH (6)). The ac and dc magnetic susceptibility measurements on randomly oriented polycrystalline samples of 1–6 revealed that they were weak ferromagnets (canted antiferromagnets) below TN. The single-crystal magnetization measurements clarified the TN’s and the cant angles at 2 K as follows: TN = 5.6 K, θ = 1.3°(H || c) for 1; TN = 3.3 K, θ = 16°(H || c) for 2; TN = ca. 2 K, θ = 7.1°(H || b) for 5. The magnetic ground state seems to be related with single-ion anisotropy of the metal ions and the spin canting may take place as a combined result of the axial or in-plane anisotropy and antiferromagnetic interaction. The incorporated guest molecule tunes the single-ion anisotropy of the host metal ions, and consequently the magnetic phase transition phenomena were drastically different depending on the guest molecules.
Synthesis and Characterization of New trans
N,N′-Disubstituted Macrocyclic “tet a” Ligands and Their Copper(II) and Nickel(II) Complexes: Structural, Electrochemical, Magnetic, and Catalytic Studies
Authors: Sengottuvelan Nallathambi , Saravanakumar Duraisamy , Narayanan Vengidusamy , Kandaswamy Muthusamy , Chinnakali Kandaswamy , Senthilkumar Gopal 
Published: June 2004

Abstract
New trans-disubstituted macrocyclic ligands (L1), trans-1,8-[N,N′-bis{(3-formyl-2-hydroxy-5-methyl)benzyl}]-1,4,8,11-tetraaza-5,5,7,12,12,14-hexamethylcyclotetradecane, and (L2), 1,8-[N,N′-bis{(3-formyl-2-hydroxy-5-methyl)benzyl}]-4,11-dimethyl-1,4,8,11-tetraaza-5,5,7,12,12,14-hexamethylcyclotetradecane, were synthesized. The ligands were characterized by elemental analysis, IR, 1H and 13C NMR spectral analyses. The ligand L1 crystallized as monoclinic in the space group P21/n, and the final R-value was found to be 0.062. Copper(II) and nickel(II) complexes of these ligands were prepared and characterized by elemental analysis, IR, UV–visible, FAB-mass spectral studies. Electrochemical studies of the nickel(II) complexes show one-electron quasireversible reduction around −1.00 to −1.13 V and one-electron quasireversible oxidation around 1.00 to 1.14 V. The copper(II) complexes show one-electron quasireversible reduction around −0.93 to −1.10 V. ESR spectral studies of the copper(II) complexes show hyperfine splitting with a g|| value of 2.31, a g⊥ value of around 2.02 and an A value of 160 G. The magnetic moment values (μeff) of the Cu(II) complexes fall in the range of 1.71 to 1.72 B.M. at room temperature (298 K). The rate-constant values of the catalytic hydrolysis of p-nitrophenyl phosphate for the copper(II) complexes were in the range 6.3 × 10−3 to 12.2 × 10−3 min−1 and for the nickel(II) complexes in the range 10 × 10−3 to 14 × 10−3 min−1. The rate-constant values of the catalytic oxidation of catechol to o-quinone were in the range 9.4 × 10−3 to 13.4 × 10−3 min−1 for the copper(II) complexes. The copper(II) and nickel(II) complexes of ligand L2 have higher catalytic activity than that of ligand L1.
Reaction of Mixed-Ligand Iron–Sulfur Cluster [Fe4(Cp*)3(Ph2C2S2)(μ3-S)3(μ3-S2)] (Cp* = C5Me5) with Methyl Iodide. Synthesis, Structure, and Redox Behavior of [Fe4(Cp*)3(Ph2C2S2)(μ3-S)3(μ3-S2Me)]
Authors: Inomata Shinji , Hitomi Keiichi , Ogino Hiroshi 
Published: June 2004

Abstract
The reaction of the mixed-ligand iron–sulfur cluster [Fe4(Cp*)3(Ph2C2S2)(μ3-S)3(μ3-S2)] ([3]) (Cp* = C5Me5) with iodomethane gave a methylated cluster, [Fe4(Cp*)3(Ph2C2S2)(μ3-S)3(μ3-S2Me)]I ([4]I), in 60% yield. The anion exchange of [4]I with KPF6 gave [4]PF6 as a pure sample. A similar treatment of [3] using iodoethane afforded an ethylated cluster, [Fe4(Cp*)3(Ph2C2S2)(μ3-S)3(μ3-S2Et)]I ([5]I), and oxidized parent cluster [3]I. The reaction of [3] with 2-iodopropane did not give an alkylated cluster. An unreacted cluster [3] was recovered with a small amount of oxidized cluster [3]I. The molecular structure of [Fe4(Cp*)3(Ph2C2S2)(μ3-S)3(μ3-S2Me)] ([4]), which was obtained by the reduction of [4]PF6 with cobaltocene, was determined by an X-ray diffraction study. Crystallographic data are: Monoclinic, P21/a, a = 21.707(2) Å, b = 21.382(2) Å, c = 11.433(1) Å, β = 98.98(1)°, V = 5241.5(9) Å3, Z = 4, and R = 0.067 for 7412 reflections with |Fo| &gt; 3σ(Fo). The methyl group transferred from MeI is located on the singly ligating sulfur atom in the disulfide ligand of the parent cluster [3]. A cyclic voltammogram of [4]PF6 in 0.1 mol dm−3 tetrabutylammonium tetrafluoroborate–CH3CN showed five reversible one-electron redox waves at E1/2 = +1.42 V, +0.92 V, +0.41 V, −0.38 V, and −1.22 V vs SCE, corresponding to 4+/3+, 3+/2+, 2+/1+, 1+/0, and 0/1− charged cluster couples, respectively. An irreversible two-electron reduction wave was also observed at Epc = −1.97 V vs SCE.
Origin of Regioselectivity in Photocycloaddition Reactions of 2-Cyclohexenone with Cycloalkenecarboxylates
Authors: Odo Yuka , Shimo Tetsuro , Hori Kenji , Somekawa Kenichi 
Published: June 2004

Abstract
The regiochemical results in [2 + 2]photocycloaddition of 2-cyclohexenone (1) with 1-cycloalkenecarboxylates (2–4) significantly changed from head-to-head (hh) to head-to-tail (ht) adducts depending on increments of the ring-size, from four to six, of the carboxylates. The root of the drastic regioselective change was inferred from the transition state (TS) analysis of the triplet reactions, including the back-reaction at the PM5 and B3LYP levels. The TS energy of the first step (TS1) is the most important factor for this reaction. The change in TS energies at hh adducts was larger than that at ht adducts. For more detailed analysis, the TS energies of the hh and ht reactions (at the three reactions) were partitioned to the two reactant deformation (Edf) and the interaction (or repulsion, Eint) energies. The Edf and Eint energy changes were found to be dependent on the ring-size of the 1-cycloalkenecarboxylates 2–4. Thus, since the larger ring of 4 has relatively higher TS1 and deformation energies for giving the hh adduct, they may cause the preferential formation of the ht adduct, and result in the significant changes in the ht/hh ratio owing to the ring-size. The root of the significant hh diminution may be the dipole–dipole repulsion between the enone carbonyl and larger carboxylate (4) moieties. The improved PM5 and B3LYP/6-31+G(d) calculations are effective and economical for disclosing the origin of regioselectivity in [2 + 2]photocycloadditions.
Mechanistic Studies on Nitrosation–Deaminocyclization of Mono-Carbamoylated Vicinal Amino Alcohols and Diols: A New Preparative In Situ Formation of Ethanediazo Hydroxide for the Ethylation of Carboxylates under Mild Conditions
Authors: Suzuki Masumi , Sugai Takeshi 
Published: June 2004

Abstract
While the cyclization of N-carbamoylamino alcohols into oxazolidinones via the activation with NO+ underwent smoothly, we found that similar reactions of vicinal diol monocarbamates were very slow. Mechanistic studies by means of time-resolved IR measurements of the former reaction suggested that the initial O-nitrosation was the rate-determining step. Indeed, the introduction of an ethyl group on the nitrogen terminus of diol monocarbamate promoted the desired cyclic carbonate formation. The concomitantly formed ethanediazo hydroxide, the precursor of the protonated form of diazoethane, was evidenced by trapping with p-nitrobenzoic acid as an ethyl ester. The formation of ethyl ester accelerates the reaction in an irreversible manner. Based on an elaboration of the substrates and reaction conditions, 2,3-dimethyl-2,3-butanediol mono-N-ethyl-N-nitrosocarbamate, which is easily prepared in situ from the corresponding ethylcarbamate and t-butyl nitrite, was developed as a new ethylation reagent of various carboxylic acids under mild conditions.
Synthesis and Gas Sensing Properties of Polypyrrole/MoO3-Layered Nanohybrids
Authors: Matsubara Ichiro , Hosono Kouta , Murayama Norimitsu , Shin Woosuck , Izu Noriya 
Published: June 2004

Abstract
Intercalative hybrid materials, comprised of polypyrrole (PPy) chains interleaved with the layers of MoO3, have been synthesized using concomitant ion exchange reaction. The (PPy)xMoO3-pressed pellets show a semiconducting-like transport with an activation energy of 0.2 eV. The MoO3 host layers play a dominant role in the determination of the transport properties of (PPy)xMoO3. The (PPy)xMoO3-pressed pellets show a distinct response to volatile organic compounds (VOCs) by increasing their electrical resistivity, which could be induced by the incorporation of VOC molecules into the interlayers of (PPy)xMoO3. (PPy)xMoO3 exhibits higher sensitivities to polar analytes such as formaldehyde and acetaldehyde, whereas it shows almost no response to toluene and benzene.