bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of Minus-Strand Templates and Replication Complexes Produced by a P23-Cleavage-Defective Mutant of Sindbis Virus
Authors: Mai Junbo , Sawicki Stanley G. , Sawicki Dorothea L. 
Published: June 2009

ABSTRACT

SIN2V is an engineered mutant Sindbis virus (SIN) that is unable to process the P23 cleavage site in polyproteins P123 and P1234 that are translated from the genome after its entry into cells. Unlike wild-type (wt) SIN, it caused minus strands to be made continuously and replication-transcription complex (RTC) activity to be unstable (R. Gorchakov, E. Frolova, S. Sawicki, S. Atasheva, D. Sawicki, and I. Frolov, J. Virol.
82:
6218-6231, 2008). We examined further the effects of P23 on SIN RNA replication and RTC activity. Continuous minus-strand synthesis by SIN2V produced 250% of wt levels of minus strands but accumulated only 110% of wt levels (0.39 pg, or 2.7 × 10
4
molecules of double-stranded RNA per cell). Because SIN2V-infected cells accumulated only 40% of the minus strands that were made, cells must possess some process to limit RTC accumulation. The loss of activity by SIN2V RTC after translation was inhibited was stochastic and not due to their inherent instability, based on finding that activity was lost without the degradation of the minus-strand templates. In addition to their normal functions, P23 RTCs exhibited the novel phenotype of being unable to switch from making less to making more genomes than subgenomic 26S mRNA at late times during infections. Our results lend credence to the hypothesis that nsP2 (and possibly nsP3) possesses functions other than those needed solely for RTC activity and that it may also act with the host to regulate minus-strand synthesis and the stability of the RTC.
The First Virally Encoded Cytochrome P450
Authors: Lamb David C. , Lei Li , Warrilow Andrew G. S. , Lepesheva Galina I. , Mullins Jonathan G. L. , Waterman Michael R. , Kelly Steven L. 
Published: June 2009

ABSTRACT

The genome sequence of the giant virus
Acanthamoeba polyphaga
mimivirus revealed the presence of two putative cytochrome P450 (
CYP
) genes. The product of one of the two predicted
CYP
genes (YP_143162) showed low-level homology to sterol 14-demethylase (CYP51) and contained a C-terminal polypeptide domain of unknown function. YP_143162 expression (without an N-terminal membrane binding domain) in
Escherichia coli
yields a CYP protein which gives a reduced CO difference maximum at 448 nm and was formally demonstrated as the first viral cytochrome P450. Analysis of binding of lipid and sterol substrates indicated no perturbation in CYP heme environment, and an absence of activity was seen when 14-methyl sterols were used as a substrate. The function of the CYP protein and its C-terminal domain remain unknown.
Four Conserved Cysteine Residues of the Hepatitis B Virus Polymerase Are Critical for RNA Pregenome Encapsidation
Authors: Kim Seahee , Lee Jehan , Ryu Wang-Shick 
Published: June 2009

ABSTRACT
Hepadnaviruses replicate via reverse transcription of an RNA template, the pregenomic RNA (pgRNA). Although hepadnaviral polymerase (Pol) and retroviral reverse transcriptase are distantly related, some of their features are distinct. In particular, Pol contains two additional N-terminal subdomains, the terminal protein and spacer subdomains. Since much of the spacer subdomain can be deleted without detrimental effects to hepatitis B virus (HBV) replication, this subdomain was previously thought to serve only as a spacer that links the terminal protein and reverse transcriptase subdomains. Unexpectedly, we found that the C terminus of the spacer subdomain is indispensable for the encapsidation of pgRNA. Alanine-scanning mutagenesis revealed that four conserved cysteine residues, three at the C terminus of the spacer subdomain and one at the N terminus of the reverse transcriptase subdomain, are critical for encapsidation. The inability of the mutant Pol proteins to incorporate into nucleocapsid particles, together with other evidence, argued that the four conserved cysteine residues are critical for RNA binding. One implication is that these four cysteine residues might form a putative zinc finger motif. Based on these findings, we speculate that the RNA binding activity of HBV Pol may be mediated by this newly identified putative zinc finger motif.
Maternal Transmission of Human Immunodeficiency Virus Escape Mutations Subverts HLA-B57 Immunodominance but Facilitates Viral Control in the Haploidentical Infant
Authors: Schneidewind Arne , Tang Yanhua , Brockman Mark A. , Ryland Elizabeth G. , Dunkley-Thompson Jacqueline , Steel-Duncan Julianne C. , St. John M. Anne , Conrad Joseph A. , Kalams Spyros A. , Noel Francine , Allen Todd M. , Christie Celia D. , Feeney Margaret E. 
Published: June 2009

ABSTRACT
Expression of HLA-B57 is associated with restricted replication of human immunodeficiency virus (HIV), but the mechanism for its protective effect remains unknown. If this advantage depends upon CD8 T-cell recognition of B57-restricted epitopes, mother-to-child transmission of escape mutations within these epitopes could nullify its protective effect. However, if the B57 advantage is largely mediated by selection for fitness-attenuating viral mutations within B57-restricted epitopes, such as T242N in TW10-Gag, then the transmission of such mutations could facilitate viral control in the haploidentical infant. We assessed the consequences of B57-associated mutations on replication capacity, viral control, and clinical outcome after vertical transmission in 13 mother-child pairs. We found that expression of HLA-B57 was associated with exceptional control of HIV during infancy, even when mutations within TW10 and most other B57-restricted epitopes were transmitted, subverting the natural immunodominance of HLA-B57. In contrast, most B57-negative infants born to B57-positive mothers progressed rapidly to AIDS. The presence of T242N led to a reproducible reduction in viral fitness, as demonstrated by in vitro assays using NL4-3 constructs encoding p24 sequences from individual mothers and infants. Associated compensatory mutations within p24-Gag were observed to reverse this impairment and to influence the propensity of T242N to revert after transmission to B57-negative hosts. Moreover, primary failure to control viremia was observed in one infant to whom multiple compensatory mutations were transmitted along with T242N. These parallel in vivo and in vitro data suggest that HLA-B57 confers its advantage primarily by driving and maintaining a fitness-attenuating mutation in p24-Gag.
Shedding of Vaccine Viruses with Increased Antigenic and Genetic Divergence after Vaccination of Newborns with Monovalent Type 1 Oral Poliovirus Vaccine
Authors: van der Sanden Sabine , Pallansch Mark A. , van de Kassteele Jan , El-Sayed Nasr , Sutter Roland W. , Koopmans Marion , van der Avoort Harrie 
Published: June 2009

ABSTRACT
For the final stages in the eradication of poliovirus type 1 (P1), the World Health Organization advocates the selective use of monovalent type 1 oral poliovirus vaccine (mOPV1). To compare the immunogenicity of mOPV1 with that of trivalent OPV (tOPV) in infants, a study was performed in Egypt in 2005. Newborns were vaccinated with mOPV1 or tOPV immediately after birth and were challenged with mOPV1 after 1 month. Vaccination with mOPV1 at birth resulted in significantly higher seroconversion against P1 viruses and lower excretion of P1 viruses than vaccination with tOPV. Intratypic differentiation of the viruses shed by the newborns revealed the presence of remarkably high numbers of antigenically divergent (AD) P1 isolates, especially in the mOPV1 study group. The majority of these AD P1 isolates (71%) were mOPV1 challenge derived and were shed by newborns who did not seroconvert to P1 after the birth dose. Genetic characterization of the viruses revealed that amino acid 60 of the VP3 region was mutated in all AD P1 isolates. Isolates with substitution of residue 99 of the VP1 region had significantly higher numbers of nonsynonymous mutations in the VP1 region than isolates without this substitution and were preferentially shed in the mOPV1 study group. The widespread use of mOPV1 has proven to be a powerful tool for fighting poliovirus circulation in the remaining areas of endemicity. This study provides another justification for the need to achieve high vaccination coverage in order to prevent the circulation of AD strains.
Nipah Virus Sequesters Inactive STAT1 in the Nucleus via a P Gene-Encoded Mechanism
Authors: Ciancanelli Michael J. , Volchkova Valentina A. , Shaw Megan L. , Volchkov Viktor E. , Basler Christopher F. 
Published: June 2009

ABSTRACT

The Nipah virus (NiV) phosphoprotein (P) gene encodes the C, P, V, and W proteins. P, V, and W, have in common an amino-terminal domain sufficient to bind STAT1, inhibiting its interferon (IFN)-induced tyrosine phosphorylation. P is also essential for RNA-dependent RNA polymerase function. C is encoded by an alternate open reading frame (ORF) within the common amino-terminal domain. Mutations within residues 81 to 113 of P impaired its polymerase cofactor function, as assessed by a minireplicon assay, but these mutants retained STAT1 inhibitory function. Mutations within the residue 114 to 140 region were identified that abrogated interaction with and inhibition of STAT1 by P, V, and W without disrupting P polymerase cofactor function. Recombinant NiVs were then generated. A G121E mutation, which abrogated inhibition of STAT1, was introduced into a C protein knockout background (C
ko
) because the mutation would otherwise also alter the overlapping C ORF. In cell culture, relative to the wild-type virus, the C
ko
mutation proved attenuating but the G121E mutant virus replicated identically to the C
ko
virus. In cells infected with the wild-type and C
ko
viruses, STAT1 was nuclear despite the absence of tyrosine phosphorylation. This latter observation mirrors what has been seen in cells expressing NiV W. In the G121E mutant virus-infected cells, STAT1 was not phosphorylated and was cytoplasmic in the absence of IFN stimulation but became tyrosine phosphorylated and nuclear following IFN addition. These data demonstrate that the gene for NiV P encodes functions that sequester inactive STAT1 in the nucleus, preventing its activation and suggest that the W protein is the dominant inhibitor of STAT1 in NiV-infected cells.
Significant Influence of the Boreal Summer Monsoon Flow on the Indian Ocean Response during Dipole Events
Authors: Krishnan R. , Swapna P. 
Published: June 2009

Abstract
A majority of positive Indian Ocean dipole (IOD) events in the last 50 years were accompanied by enhanced summer monsoon circulation and above-normal precipitation over central-north India. Given that IODs peak during boreal autumn following the summer monsoon season, this study examines the role of the summer monsoon flow on the Indian Ocean (IO) response using a suite of ocean model experiments and supplementary data diagnostics. The present results indicate that, if the summer monsoon Hadley-type circulation strengthens during positive IOD events, then the strong off-equatorial southeasterly winds over the northern flanks of the intensified Australian high can effectively promote upwelling in the southeastern tropical Indian Ocean and amplify the zonal gradient of the IO heat content response. While it is noted that a strong monsoon cross-equatorial flow by itself may not generate a dipolelike response, a strengthening (weakening) of monsoon easterlies to the south of the equator during positive IOD events tends to reinforce (hinder) the zonal gradient of the upper-ocean heat content response. The findings show that an intensification of monsoonal winds during positive IOD periods produces nonlinear amplification of easterly wind stress anomalies to the south of the equator because of the nonlinear dependence of wind stress on wind speed. It is noted that such an off-equatorial intensification of easterlies over the SH enhances upwelling in the eastern IO off Sumatra–Java, and the thermocline shoaling provides a zonal pressure gradient, which drives anomalous eastward equatorial undercurrents (EUC) in the subsurface. Furthermore, the combination of positive IOD and stronger-than-normal monsoonal flow favors intensification of shallow transient meridional overturning circulation in the eastern IO and enhances the feed of cold subsurface off-equatorial waters to the EUC.
Nonpermissive HLA-DPB1 disparity is a significant independent risk factor for mortality after unrelated hematopoietic stem cell transplantation
Authors: Crocchiolo Roberto , Zino Elisabetta , Vago Luca , Oneto Rosi , Bruno Barbara , Pollichieni Simona , Sacchi Nicoletta , Sormani Maria Pia , Marcon Jessica , Lamparelli Teresa , Fanin Renato , Garbarino Lucia , Miotti Valeria , Bandini Giuseppe , Bosi Alberto , Ciceri Fabio , Bacigalupo Andrea , Fleischhauer Katharina ,   for the Gruppo Italiano Trapianto di Midollo Osseo, Cellule Staminale Ematopoietiche (CSE) e Terapia Cellulare, and the Italian Bone Marrow Donor Registry
Published: June 2009

AbstractThe importance of donor-recipient human leukocyte antigen (HLA)-DPB1 matching for the clinical outcome of unrelated hematopoietic stem cell transplantation (HSCT) is controversial. We have previously described an algorithm for nonpermissive HLA-DPB1 disparities involving HLA-DPB1*0901,*1001,*1701,*0301,*1401,*4501, based on T-cell alloreactivity patterns. By revisiting the immunogenicity of HLA-DPB1*02, a modified algorithm was developed and retrospectively tested in 621 unrelated HSCTs facilitated through the Italian Registry for oncohematologic adult patients. The modified algorithm proved to be markedly more predictive of outcome than the original one, with significantly higher Kaplan-Meier probabilities of 2-year survival in permissive compared with nonpermissive transplantations (55% vs 39%, P = .005). This was the result of increased adjusted hazards of nonrelapse mortality (hazard ratio [HR] = 1.74; confidence interval [CI], 1.19-2.53; P = .004) but not of relapse (HR = 1.02; CI, 0.73-1.42; P = .92). The increase in the hazards of overall mortality by nonpermissive HLA-DPB1 disparity was similar in 10 of 10 (HR = 2.12; CI, 1.23-3.64; P = .006) and 9 of 10 allele-matched transplantations (HR = 2.21; CI, 1.28-3.80; P = .004), both in early-stage and in advanced-stage disease. These data call for revisiting current HLA matching strategies for unrelated HSCT, suggesting that searches should be directed up-front toward identification of HLA-DPB1 permissive, 10 of 10 or 9 of 10 matched donors.
The Influence of Aggregate Interaction and Aging Procedure on Bitumen Aging
Authors: Wu Jiantao , Airey Gordon 
Published: June 2009

Abstract
Bitumen, like many other organic substances, is affected by the presence of oxygen, ultraviolet radiation, and by changes in temperature. These external influences result in the phenomenon known as “aging” and cause changes in the chemical composition and therefore the rheological and mechanical properties of the bitumen. Aging is primarily associated with the loss of volatile components and oxidation of the bitumen during asphalt mixture production (short-term aging) and progressive oxidation of the in-place material in the field (long-term aging). Both factors cause an increase in viscosity (or stiffness) of the bitumen and consequential stiffening of the asphalt mixture. Aging at moderate levels is generally accepted and can even enhance performance, but at significant levels results in embrittlement of the bitumen, significantly affecting its adhesive characteristics and usually resulting in reduced cracking resistance of the asphalt mixture under repeated loading. It has long been recognized that the characteristics of bitumens are affected by the mineral aggregate with which they come into contact and that age hardening is influenced by both the bitumen and the mineral aggregate as reported by Bell and Sosnovske in 1994. This paper investigates the influence of aggregate type and aging procedure on the rheological and chemical fractional properties of aged bitumen. Asphalt mixtures comprising limestone or granite aggregate have been artificially aged in the laboratory and the rheological properties and chemical composition of the recovered bitumen from the mixtures determined after different durations of aging. In addition, the influence of bulk aging versus thin film aging has been assessed on the same bitumen aged in the presence of aggregate.
Performance of Composite Modified Asphalt with Trinidad Lake Asphalt used as Waterproofing Material for Bridge Deck Pavement
Authors: Cao Wei-Dong , Yao Zhan-Yong , Liu Shu-tang , Cui Xin-Zhuang 
Published: June 2009

Abstract
Performance of composite modified asphalt with Trinidad Lake Asphalt (TLA) used as waterproofing material for bridge deck pavement was studied through the shear test, pull-out test, and water permeability test. The results showed that shear strength at 20°C of composite modified asphalt with TLA was affected by the material dosage and the optimum dosage was 1.2 kg/m2. Shear strength at 20°C of composite modified asphalt with TLA increased with the increase of TLA content and then decreased with the further increase of TLA content. However, the shear strength at 50°C shows different results. Based on shear strength at 20°C, the optimum TLA content was 20 % by total weight of composite modified asphalt. Bond strength at 20°C of composite modified asphalt with TLA was very close to that of styrene-butadiene-styrene (SBS) modified asphalt but the bond strength at 50°C of composite-modified asphalt with TLA was 47 % higher than that of SBS modified asphalt. Both composite modified asphalts with TLA and with SBS modified asphalt met the impermeability requirement. Composite modified asphalt with TLA could be used as waterproofing material for bridge deck pavement for better performance.
Testosterone treatment of ovariectomized rats: Effects on lipolysis regulation in adipocytes
Authors: De Pergola Giovanni , Holmäng Agneta , Svedberg Jan , Giorgino Riccardo , Björntorp Per 
Published: June 2009

Abstract.
The effects of testosterone treatment (2 mg every 14 days, for three months) on adipocyte lipolysis of intact (250-300 g body weight) and ovariectomized female rats were studied. Testosterone treatment of intact rats had no effect. Ovariectomy was followed by an increase in fat cell size and a decrease of lipolysis stimulated by isoproterenol, norepinephrine, epinephrine, forskolin, cAMP and isobutylmethylxantine. The number of βadrenergic receptors was reduced. There was, however, no change in the antilipolytic effects of UK 14,304 (alpha2-adrenergic agonist), nicotinic acid, N6-phenylisopropyladenosine or insulin. Testosterone treatment of ovariectomized rats restored the number of β-adrenoceptors and lipolysis stimulated by cAMP and isobutylmethylxantine, but not lipolysis stimulated by catecholamines and forskolin, suggesting a remaining defect in the catalytic unit of adenylate cyclase. These results indicate that ovariectomy is followed by a profound derangement of the lipolytic pathway at several levels, from β-adrenoceptors number to the triglyceride lipase activity. This is partially restored by treatment with testosterone, which, however, has no effect on intact female rats. This study emphasizes the importance of ovarian integrity for the lipolytic regulation and the inability of testosterone to replace ovarian function in this regard or to affect lipolysis in intact female rats.
Early changes in thyroid hormone metabolism in the heart, liver, and brown adipose tissue during the induction of low T3 syndrome in streptozotocin-diabetic rats
Authors: Gøtzsche Liv S. Bjørn-Hansen , Gøtzsche Ole , Flyvbjerg Allan , Boye Niels 
Published: June 2009

Abstract.
In order to elucidate the day-by-day development of low T3 syndrome, we made rats diabetic by an injection of streptozotocin. Untreated controls killed at day 0 and rats treated for 8 days with insulin after they had received streptozotocin served as controls. Subgroups of animals were killed 1, 2, 3, 4 and 8 days after streptozotocin. In serum, heart and liver, T3 was depressed to less than 50% of controls at day 4, whereas the insulin-treated rats differed from controls only as to heart T3. Heart iodothyronine 5'-deiodinase activity was depressed to a minimum at day 3 and depression was not prevented by insulin. Liver iodothyronine 5'-deiodinase activity had not reached a minimum at day 8, and again, insulin treatment did not normalize this parameter. T3 contents and iodothyronine 5'-deiodinase activity in brown adipose tissue did not differ from values in controls at any point of time. Thus, in the rats with low T3 syndrome induced by streptozotocin-diabetes, a lowered iodothyronine 5'-deiodinase activity is not fully inhibited by insulin treatment, whereas the T3 content in the liver is re-established during an observation period of 8 days. A direct toxic effect of streptozotocin seems unlikely as an in vitro study showed no influenze of streptozotocin on iodothyronine 5'-deiodinase activity in the liver. The study thus indicates that iodothyronine 5'-deiodinase activity in the heart and liver is depressed in experimental diabetes, despite near optimal regulation of blood glucose, and we suggest that lowered intracellular T3 production could, after some time, result in a hypothyroid state in different tissues.
Effect of thalidomide on the incidence of iodine-induced and spontaneous lymphocytic thyroiditis and spontaneous diabetes mellitus in the BB/Wor rat
Authors: Lueprasitsakul Wasana , Abend Susan , Alex Sharon , Reinhardt Walter , Appel Michael C. , Braverman Lewis E. 
Published: June 2009

Abstract.
Thalidomide, a derivative of glutamic acid, has immunosuppressive effects and suppresses graft-vs-host disease in the rat and following bone marrow transplantation in man. It is effectively used in the treatment of erythema nodosum leprosum and has a potential therapeutic effect in a variety of autoimmune diseases. In view of these observations, we evaluated the effect of thalidomide on the incidence of spontaneous and iodine-induced lymphocytic thyroiditis and spontaneous insulin dependent diabetes mellitus in the BB/Wor rat. Thalidomide did not suppress the incidence of lymphocytic thyroiditis and serum anti-thyroglobulin antibodies or affect the serum concentrations of T4, T3 and TSH in this rat model. Thalidomide also did not affect the incidence of insulin dependent diabetes mellitus. In contrast to preliminary studies in man and rat demonstrating efficacy in the therapy of autoimmune diseases, thalidomide did not prevent or suppress autoimmune lymphocytic thyroiditis or insulin-dependent diabetes mellitus in the BB/Wor rat.